Sports Physicals

OverviewNeed and cost

In the US alone, millions of athletes undergo preparticipation evaluations, and millions of healthcare hours are spent on performing these evaluations each year. Because the yield of significant abnormalities in this relatively healthy population is low, the cost-effectiveness of these evaluations has been questioned.[1]

Philosophy

The approach to preparticipation evaluations varies depending on the practitioner and practice situation, as well as on the athlete, his or her level of competition, and the institution and its requirements. At this time, 50 of 51 states (including the District of Columbia) require some form of physical evaluation before participation in sports at the high school level, of which some are legal requirements. Some practitioners approach sports physicals as thorough, periodic health evaluations, whereas others consider these evaluations to be risk-based screening examinations. Neither approach is perfect, and no universal standard exists for what constitutes an adequate or appropriate evaluation for this population.

To complicate matters further, the positional statement of the American Medical Association (AMA) regarding such evaluations is vague and may be interpreted in many ways.[2] According to the AMA, every athlete has the right to a thorough preseason evaluation. Typically, these evaluations are not considered substitutes for thorough medical care, and they are described as screening tools with the purpose of identifying high-risk situations.

Main issues

The main athletic assessment issues can be classified into 3 categories: administrative, coaching/athletic, and medical.

Athletic directors are the ones who usually address the administrative issues, which are often based on institutional policy and on local, state, or national laws. These administrative issues involve liabilities, matters to do with insurers, and the rights of athletes to participate in competitive sports. The administrators rely on the physician to assess athletes for compliance with the relevant administrative codes.

The coaching/athletic issues involve both the coaches and athletes. The athletes want medical clearance so they can safely compete and train. If they have a history of injuries or medical problems, the athletes desire information about how to treat or rehabilitate those conditions to improve their performance and safety. Coaches are interested in fielding a team of healthy athletes. When injuries or illness preclude their athletes from competing, coaches need to know the time period that is required for the injury or illness to heal so they can make decisions about finding capable substitutes. Both athletes and coaches depend on the physician to help them in making these types of decisions.

Medical issues are handled by the physician, athlete, coaching staff, and administrators. The goal is to ensure, as completely and accurately as possible, that an athlete with a specific medical condition can compete safely. Achieving this goal is usually straightforward, but a particular situation can become complicated. Although a number of guidelines are available, many are difficult to interpret or implement. Furthermore, some conditions that affect an athlete's participation in sports do not have clear-cut guidelines. The physician's role is vital in these cases. He or she must not only determine the athlete's safety but also assist team coaches in making decisions about administrative and legal matters.

Goals and objectives

The goals of a preparticipation sports evaluation can be summarized as follows:

Determine that the athlete is in general good health.Assess the athlete's present fitness level.Detect conditions that predispose the athlete to new injuries.Evaluate any existing injuries of the athlete.Assess the size and developmental maturation of the athlete.Detect congenital anomalies that increase the athlete's risk of injury.Detect poor preparticipation conditioning that may put the athlete at increased risk.

For excellent patient education resources, visit eMedicineHealth's Healthy Living Center. Also, see eMedicineHealth's patient education articles Walking for Fitness and Strength Training.

NextTiming, Frequency, and Types of EvaluationsTiming of the evaluation

The timing of an athletic preparticipation evaluation is dependent upon the season of the sport. Many evaluations are performed throughout an entire institution that has teams competing in many sports during various seasons. In this circumstance, one approach is to perform the evaluations before each major season. This approach may be optimal for each sport in its season, but it also requires organization and frequent involvement by the medical team. Another approach is to conduct all physical examinations for the institution at the same time each year. Although this approach is more convenient for the medical team, the evaluations may not be optimally timed for all sports.

The optimal timing for the preparticipation sports evaluation is approximately 6 weeks before the onset of the sports season because this period affords time for the further evaluation of any problems that are discovered, if indicated. If treatable problems are detected, some rehabilitation success can be achieved during those 6 weeks. Furthermore, unconditioned athletes may have an opportunity to improve their conditioning in this time and, thus, hopefully prevent other injuries.

If the physical examination is performed less than 6 weeks before the start of a sports season, some athletes may not have time to recover, become conditioned, or complete a specific evaluation that may necessitate medical clearance for play. As a result, athletes may miss part of the sports season. If the preparticipation evaluation is performed earlier, there is time for other conditions to develop, and the findings of the initial evaluation may no longer be up to date.

Frequency of evaluations

No requirements are established for the frequency of these physical evaluations. Approaches vary from annual evaluations to season-specific examinations to single evaluations performed when an athlete enters a sports program.

High schools typically require annual evaluations before a student's participation. These are usually considered valid for the entire academic season and may diminish the number of evaluations needed by multisport athletes.

Many higher-level institutions use thorough initial evaluations upon the student's admission to its athletic programs, with annual follow-up examinations that are focused on particular items and a review of the athlete's medical history. Some of these follow-up examinations may address only the history if the individual is healthy. If abnormalities are detected on the history screening, these problems are evaluated thoroughly.

In a number of organized professional sports, such as football, preseason and postseason physical examinations are the standard.

Types of evaluations

Two extremes exist in the spectrum of the types of athletic preparticipation evaluations: one by the athlete's personal physician and the other by multiple providers in a multistation setting. Either evaluation is adequate if the proper documentation is completed.

At one end of the spectrum is an evaluation in a private office setting or by the athlete's personal physician. These make up a small percentage of all sports evaluations. The private office examination is ideal from the standpoint of continuity of care. Furthermore, the athlete may feel at ease in the surroundings of a familiar physician. The main drawback to this approach is the difficulty of performing many of these evaluations in the office settings.

At the other end of the spectrum of athletic preparticipation examinations is the multistation evaluation, which involves multiple providers and examination-based specialists. In this approach, a primary care physician may review the patient's history; check his or her vital signs; and examine the abdomen, lungs, and genitals. A cardiologist may then examine the heart, a neurologist performs neurologic testing, a physiatrist assesses the athlete's flexibility, and an orthopedist completes the musculoskeletal evaluation.

This multistation approach requires a coordinated effort of many more personnel. These types of evaluations are often performed in gymnasiums, locker rooms, or auditoriums; thus, privacy for the patient is lost. Multistation evaluation is ideal for large volumes of athletes and provides immediate access to a specialist if abnormalities surface. To achieve patient cooperation, personnel such as coaches may assist in supervising athletes who are waiting to be examined. Trainers and therapists are often used to assess vital signs, evaluate visual acuity, and assess flexibility and range of motion. See Table 1 for common requirements for station-based setup.

Table 1. Requirements for Station-Based Preparticipation Physical Evaluations (Open Table in a new window)

Stations Personnel Required

Sign in

Height and weight

Vital signs

Vision

Physical examination*

Medical history review, assessment, and clearance

Ancillary personnel (coach, nurse, community volunteer)

Ancillary personnel

Ancillary personnel

Ancillary personnel

Physician

Physician

Optional

Nutrition

Dental

Injury evaluation†

Flexibility

Body composition

Strength

Speed, agility, power endurance, balance

Dietitian

Dentist

Physician

Athletic trainer, physical therapist

Athletic trainer, exercise physiologist, physical therapist

Athletic trainer, coach, exercise physiologist, physical therapist

Athletic trainer, coach, exercise physiologist

*The physical examination can be subdivided if more than 1 physician is present. Qualified medical personnel may perform the musculoskeletal examination under the direction of a physician. †A station for the evaluation of musculoskeletal injury may be used to provide a more complete evaluation when a musculoskeletal injury is detected during the required musculoskeletal screening examination.

With the multistation approach, a lead physician should be designated. This physician reviews the results from all the stations and signs the needed forms to clear the athlete for play. The lead physician also checks to ensure that nothing is missed and supplies the appropriate personnel information about athletes who have abnormalities, including those who are still able to compete.

PreviousNextHistory

A thorough medical history is the most fruitful tool in the athletic preparticipation evaluation. When completed and thoroughly reviewed, this history supplies most of the information that is needed to decide if an athlete can safely compete in a given sport.

Many established tools are available to facilitate the collection of key medical information. Much research and thought has gone into the forms that are jointly recommended by the American Osteopathic Academy of Sports Medicine (AOASM), the American Academy of Family Physicians (AAFP), the American Medical Society for Sports Medicine (AMSSM), and the American Orthopaedic Society for Sports Medicine (AOSSM). These forms are easily accessible.

An athlete's medical history should focus on the detection of previous and current disease, previous and current injuries, cardiovascular abnormalities, and musculoskeletal abnormalities. If the athlete's medical history suggests the presence of any of these problems, question him or her for further details, and strongly consider other testing to evaluate these problems.

Key issues that must be addressed in a sports medical history include the following:

Demographic data: Updated information is critical, especially in athletes who are minors. Telephone contact numbers are also essential because the authorization to treat specific conditions may be needed. Tetanus status: With any athletic endeavor, the risk of abrasion and laceration increases as the risk of injury increases. All athletes should be current regarding tetanus immunization. History of excessive weight loss or gain: Changes in weight can indicate eating disorders, steroid abuse, and purging behavior. These disorders are seen not only in female athletes in gymnastics, dance, figure skating, and diving, but also in wrestlers and other athletes. History of anaphylactic reactions: This finding is especially important if an athlete has known anaphylaxis with insect bites. Because many sports take place in an outdoor environment, insect bites are possible. If an athlete has such a history of anaphylaxis, he or she can be advised to always keep an anaphylaxis kit at hand. Furthermore, advance knowledge of an athlete's allergy can alert coaches, trainers, and team physicians to be prepared to treat this life-threatening condition. (See also the Medscape Reference article Anaphylaxis.) Recent and previous concussions: Although the mortality rate associated with head injury in sports is low, more evidence regarding the morbidity associated with repetitive head injuries is emerging.[3] Because athletes, especially those in certain sports, are at risk of head trauma, the athlete's concussion history must be assessed to identify individuals who are at risk and to determine whether they should continue playing contact or collision sports. Dizziness or collapse with exertion: Although this symptom has multiple etiologies, the possibility of heart disease and sudden cardiac death warrants an in-depth evaluation of symptoms, when present. (See also the Medscape Reference article Commotio Cordis.) Family history of exercise-related death: This is a historical finding that puts direct relatives at higher risk for the same condition. Therefore, in cases in which a family history of collapse with exercise is found, the athlete should be evaluated in depth. History of asthma: Because asthma is often triggered by exercise or exertion, the severity of the previous episodes should be evaluated further. In addition, adequate instruction about treatment can help prevent dire consequences from this condition. (See also the Medscape Reference articles Exercise-Induced Asthma [in the Sports Medicine Section] and Asthma [in the Pulmonology section].) Loss or dysfunction in 1 of a pair of organs: If the remaining organ of a pair is injured, entire function can be lost. For the most part, this assessment applies to the eyes, kidneys, and testicles. Menstrual history: An abnormality in menstrual function can be a clue to significant underlying medical conditions, including pregnancy, osteoporosis, nutritional deficits, drug abuse, psychiatric conditions, and eating disorders. (See also the Medscape Reference article Female Athlete Triad.) Use of contact lenses, dental appliances, and other devices: It is important to be aware of the athlete's use of any lenses or devices because they may become dislodged during competition, and some items should not be worn during competition. In addition, athletes may wear jewelry or have body piercings; these should be noted and assessed. Recent or recurrent fractures, dislocations, and other injuries: A history of these types of injuries may indicate a condition that requires further treatment or surgery, or it may indicate an abnormality in the athlete's playing mechanics, style, or equipment. Previous heat illness: This finding is important for certain sports that have peak play seasons during hot seasons and for sports that require the use of heavy restrictive equipment. Individuals with 1 episode of heat illness are at high risk of recurrence. (See also the Medscape Reference article Heatstroke.) Source of the history: Because many athletes are minors, their medical and surgical histories must be obtained with a parent or guardian present. If this is not convenient, history forms could be completed and then sent to a parent or legal guardian for his or her signature. Without the parent's or guardian's involvement, the athlete's history cannot always be considered reliable. PreviousNextPhysical Examination

The physical examination must be global and complete because any abnormality can affect an athlete's sports participation. However, the examination is still somewhat focused on screening for major anomalies. The athletic preparticipation physical evaluation includes a medical examination, an orthopedic examination, and performance testing. However, if the athlete's medical history reveals any problems, those problems should be examined thoroughly and not just for the purposes of screening.

A review of the skills of physical examination is beyond the scope of this article. However, the following is a list of areas that should receive specific attention in an athletic preparticipation evaluation.

Height and weight: These measures indicate growth and development and may reflect general fitness (eg, obesity) and pathology (eg, eating disorders). These measures are also valuable in evaluating an athlete's risks for competing at certain levels. For example, these data may be useful in determining if a thin freshman should play varsity football. A common minimum weight for varsity football participation is 120 lb, although this is not a strict guideline. Furthermore, some sports are classified according to the athlete's size or weight, and these measures may affect the athlete's class. Blood pressure (BP): Although a BP measurement is rarely an indication for disqualification from sports, abnormalities are often first noted during the sports physical examination setting. Athletes with BP changes can be referred for follow-up care with a primary physician. Certain sports may cause significant BP elevations, and this may be a reason to limit an athlete's participation. The BP must be evaluated more than once, and normal BPs for the athlete's age must be considered. Rough guidelines are a BP of 125/80 mm Hg or less for those aged 10-15 years and 130/85 mm Hg for those aged 16 years and older. See Table 2. Visual acuity: Visual acuity does not need to be 20/20 for sports participation, but poor vision can affect the athlete's performance and increase the likelihood of injury. If the athlete's visual acuity is abnormal, interventions can be recommended before his or her participation in sports activities. Some recommendations advocate clearance without intervention for any person with visual acuity of 20/40 or better using both eyes. Skin: Certain sports, such as wrestling, disqualify athletes who have infectious dermatoses, which include impetigo, herpes, and forms of tinea. Other conditions (eg, acne, scabies, nevi) can be detected, and the athlete should be counseled in such cases. Eyes: Pupil reactivity and anisocoria should be noted. Knowledge of preexisting abnormalities can be useful information at a later time in case an athlete has a head injury. Heart: Routine auscultation for murmurs or irregular rhythms is indicated, and auscultation should be obtained with the patient in at least 2 positions (usually sitting and supine), which increase the likelihood of detecting subtle abnormalities. A familiarity with the definitive findings of different valvular lesions is essential. The most common cause of sudden cardiac death in athletes is hypertrophic cardiomyopathy, also known as hypertrophic obstructive cardiomyopathy (HOCM) and Brock disease. The classic murmur in this anomaly is a systolic murmur along the left sternal border, which is accentuated by Valsalva maneuvers and standing; the murmur decreases with handgrip and squat maneuvers. These auscultation examinations can reveal many murmurs, which are mostly benign systolic-flow murmurs, but the examiner must have a trained ear to be able determine the need for further evaluation. Abdomen: The abdominal examination should be conducted to assess organomegaly, especially splenomegaly, because of the risk of rupture in contact sports. Genitalia: The need for a genital examination is an area of controversy among sports medicine physicians. This examination can be used for Tanner staging in adolescents to classify athletes by maturity; thus, developmental delays can be detected. The genital examination can also be used to assess males for the presence of a single testicle and to evaluate for the presence of hernias. Some sports physicians omit the genital examination unless the history indicates a single testicle or inguinal or scrotal swelling; the medical history may be adequate for finding these problems. Furthermore, unless hernias are incarcerated, sports participation may not be prohibited. Musculoskeletal: If the screening history is negative, this evaluation can be quickly completed by using the 90-second orthopedic evaluation as outlined below. Note the general body habitus.Assess the cervical range of motion.Assess shoulder function by having the athlete perform shoulder shrugs, abduction to 90°, and internal and external rotation.Visually inspect the forearms and have the athlete supinate and pronate the forearms with his or her elbows flexed to 90°.Evaluate the hands for rotational deformities by asking the athlete to open and close his or her fists and spread the fingers.Have the athlete perform a duck walk to evaluate function of the hips, knees, and ankles.Assess knee extension and patellar tracking.Ask the athlete to toe walk and heel walk.Ask the athlete to touch his or her toes to check for scoliosis.Performance Testing

Coaches and trainers often perform this test, and the physician may not be needed. The main concern in the performance evaluation is assessing the athlete's flexibility and endurance.

Flexibility can be assessed in many ways. Charts and goniometry may be used to compare ranges of motion on the right and left sides. A simple sit-and-reach test can be used to measure general lower-extremity flexibility. This information is useful in planning exercise programs for specific athletes.

Endurance can be measured with timed tests. One such test is a 12-minute run, during which the athlete's ability to complete the test and the distance covered are measured. Another evaluation is a 1.5-mile run, which is similarly used to assess the athlete's ability to complete the test and the time needed to run the distance.

Other tests may include single maximal weight lifting, timed sprinting, broad jumping, and vertical leaping.

Table 2. Classification of Hypertension by Age Group[4] (Open Table in a new window)

Age Group, y Significant Hypertension,

mm Hg

Severe Hypertension,

mm Hg

Systolic BP Diastolic BP Systolic BP Diastolic BP Children

6-9

10-12

122

126

78

82

130

134

86

90

Adolescents

13-15

15-18

136

142

86

92

144

150

92

98

Source: Report of the Second Task Force on Blood Pressure Control in Children, 1987.[4]

PreviousNextOther Screening Evaluations

The role of other screening evaluations before sports participation has been questioned. For the most part, authorities have recommended against random screening with these tools. Some of these tests are expensive, and some have been evaluated and deemed to have no significant advantage over a thorough medical history and physical evaluation. Also, false-positive findings can lead to unnecessary evaluation and investigation, which can have legal implications that set legal precedents.

One evaluation that has been considered for all athletes is electrocardiography to evaluate cardiac rhythm and cardiac size. Echocardiography is also considered a screening tool for detecting anomalies that may place the athlete at risk for sudden cardiac death. The state of Oregon proposed a protocol approach to help teach providers the most useful screening methods and to collect data over time to help focus future efforts.[5] In time, this effort may shed light on alternative approaches to screening young athletes for life-threatening cardiac anomalies.

A study of 964 athletes found abnormalities in 35% of the echocardiograms — 10% of the total deemed to require an echocardiogram. Ultimately, 0.6% of the athletes had conditions that required disqualifications from activity or further treatment or evaluations beyond echocardiography. The echocardiograms revealed no additional abnormalities when added to history, physical examination, and ECG findings.[6]

Urinalysis had long been part of the sports physical evaluation, but this test eventually proved to yield several false-positive results. At one point, complete blood cell (CBC) counts were measured to evaluate for anemias, which are common among elite athletes; however, the findings are of questionable significance at times.

Orthopedic evaluations often include radiography of the cervical spine, especially among football players. The purpose is to try to detect an athlete's risk for spinal cord injury. Studies show that this kind of screening may not be effective.

Most guidelines for athletic preparticipation evaluations do not include the above tests. Some institutions do require such studies, but these tests are generally not good as screening tools, and they should not be performed in patients with an unremarkable medical history. However, when a risk is evident, a full workup should be performed. For example, some clinicians advocate radiography of the cervical spine in athletes with Down syndrome because these individuals have a higher incidence of congenital instability in the upper cervical spine.

(See also the Medscape Reference article Down Syndrome and the Medscape News articles Part I: Clinical Practice Guidelines With Down Syndrome From Birth to 12 Years and Part II: Clinical Practice Guidelines for Adolescents and Young Adults With Down Syndrome: 12-21 Years.)

PreviousNextClearance for Sports Participation

An athlete should be medically cleared for sports participation only after the medical history and physical evaluation are deemed unremarkable. If the history or physical findings raise concerns, a negative complete workup can help in clearing the athlete for participation. Even then, however, the physician must realize that the athlete is only cleared for a specific sport. Sports with different levels of contact, static activity, and dynamic activity have different criteria for participation clearance. A single athlete may qualify to participate in 1 sport but not in another. Likewise, clearance for participation in 1 sport may not apply to another sport or another level of the same sport.

To help clarify the risks of different sports, the American Academy of Pediatrics (AAP) developed 2 sports classifications based on the level of contact and the level of intensity, as determined by the dynamic and static demands of the sport. Neither classification is all-inclusive, but most of the common sports are included. These range from popular sports, such as football, baseball, hockey, soccer, and basketball, to less common sports, such as skiing, sailing, rodeo, and weight lifting. (Note: Although water sports have their own concerns, the AAP does not consider them a category of sports.)

Contact is divided into 3 categories: contact/collision, limited contact, and noncontact (see Table 3).

Intensity is divided into 2 categories: high to moderate intensity and low intensity. Sports with high to moderate intensity can be subdivided into those with high-dynamic and high-static demands, those with high-dynamic and low-static demands, and those with low-dynamic and high-static demands (see Table 4). Low-intensity sports have low-dynamic and low-static demands; these sports include bowling, cricket, curling, golf, and riflery.

Medical clearance for a sport is easily granted in most cases because the athletes' medical histories and physical findings are often unremarkable. However, when an abnormality is detected, the sport and the severity of the abnormality must be considered together in making a decision about an athlete's participation. The AAP addresses common conditions that arise in athletic preparticipation evaluations and discusses how they are related to clearance for different sports (see Table 5). The physician in charge makes 1 of the following 4 choices[7] :

Unrestricted participation for a particular sport: If an athlete is cleared to participate in a contact sport with high dynamic and static demands, the athlete could potentially qualify to participate in any sport. However, this is not always the case. Clearance with notification of the coach, trainer, and team physician: This choice may be selected for athletes with conditions that allow their participation in a sport; however, these athletes may need special treatment on occasion. A good example is an athlete with mild to moderate and well-controlled, exercise-induced asthma. (See also the Medscape Reference article Exercise-Induced Asthma.) Deferred clearance: This category can be used when suspicious symptoms or signs indicate further workup should be conducted in an athlete, who may eventually be cleared. A good example is an athlete with a newly discovered cardiac murmur that has suspicious characteristics or an individual with a recent concussion and postconcussion syndrome. Disqualification: This category is used when a known condition prohibits an athlete's participation in the given sport. Generally, this decision is not reversible for that particular sport; however, the condition may not preclude the athlete's participation in a sport with a lower safety risk.

Sports are classified by contact level in the table below.

Table 3. Classification of Sports by Contact level (Open Table in a new window)

Contact/Collision Sports Limited-Contact Sports Noncontact Sports Basketball

Boxing*

Diving

Field hockey

Football (flag or tackle)

Ice hockey

Lacrosse

Martial arts

Rodeo

Rugby

Ski jumping

Soccer

Team handball

Water polo

Wrestling

Baseball

Bicycling

Cheerleading

Canoeing/kayaking (white water)

Fencing

Field events (high jump, pole vault)

Floor hockey

Gymnastics

Handball

Horseback riding

Racquetball

Skating (ice, inline, roller)

Skiing (cross-country, downhill, water)

Softball

Squash

Ultimate Frisbee

Volleyball

Windsurfing/surfing

Archery

Badminton

Bodybuilding

Canoeing/kayaking (flat water)

Crew/rowing

Curling

Dancing

Field events (discus, javelin, shot put)

Golf

Orienteering

Power lifting

Race walking

Riflery

Rope jumping

Running

Sailing

Scuba diving

Strength training

Swimming

Table tennis

Tennis

Track

Weight lifting

*Participation not recommended by the AAP.[7] The AAFP, AMSSM, AOASM, and AOSSM have no recommendation against boxing.

Table 4. Sports of High to Moderate Intensity (Open Table in a new window)

Sports With High to Moderate Dynamic and Static Demands Sports With High to Moderate Dynamic and Low Static Demands Sports With Low Dynamic and High to Moderate Static Demands Boxing*

Crew/rowing

Cross-country skiing

Cycling

Downhill skiing

Fencing

Football

Ice hockey

Rugby

Running (sprinting)

Speed skating

Water polo

Wrestling

Badminton

Baseball

Basketball

Field hockey

Lacrosse

Orienteering

Table Tennis

Race walking

Racquetball

Soccer

Squash

Swimming

Tennis

Volleyball

Archery

Auto racing

Diving

Equestrian activities

Field events (jumping)

Field events (throwing)

Gymnastics

Karate or judo

Motorcycling

Rodeo

Sailing

Ski jumping

Water skiing

Weight lifting

*Participation not recommended by the AAP.[7] The AAFP, AMSSM, AOASM, and AOSSM have no stand against boxing.

Table 5. Medical Conditions and Sports Participation[7] (Open Table in a new window)

Condition Explanation Participation Atlantoaxial instability (instability of the joint between cervical vertebrae 1 and 2)*The athlete needs evaluation to assess the risk of spinal cord injury during sports participation.Qualified yesBleeding disorder*The athlete needs an evaluation.Qualified yesCarditis (inflammation of the heart)Carditis may result in sudden death with exertion.NoHypertension (high BP)Those athletes with significant essential (unexplained) hypertension should avoid weight lifting and power lifting, body building, and strength training. Those with secondary hypertension (hypertension caused by a previously identified disease) or severe essential hypertension need evaluation.†Qualified yesCongenital heart disease (structural heart defects present at birth) Those athletes with mild forms of congenital heart disease may participate fully. Those with moderate or severe forms and those who have undergone surgery need evaluation.‡Qualified yesDysrhythmia (irregular heart rhythm)The athlete needs evaluation because some types of cardiac dysrhythmia require therapy, make certain sports dangerous, or both. Qualified yesMitral valve prolapse (abnormal heart valve Those athletes with symptoms (chest pain, symptoms of possible dysrhythmia) or evidence of mitral regurgitation (leaking) on physical examination need evaluation. All others may participate fully. Qualified yesHeart murmurIf the murmur is innocent (ie, it does not indicate heart disease), full participation is permitted. Otherwise, the athlete needs an evaluation (see Congenital heart disease and Mitral valve prolapse, above). Qualified yesCerebral palsy*The athlete needs an evaluation.Qualified yesDiabetes mellitus*If the diabetes is well controlled, the athlete can play in all sports with proper attention to diet, hydration, and insulin therapy. Particular attention is needed for activities that last 30 minutes or more. YesDiarrhea§Unless the disease is mild, no participation is permitted because diarrhea may increase the risk of dehydration and heat illness. (See Fever, below.) Qualified noAnorexia nervosa, bulimia nervosaPatients need both medical and psychiatric assessments before sports participation.Qualified yesFunctionally 1-eyed athlete, loss of an eye, detached retina, previous eye surgery, or serious eye injuryA functionally 1-eyed athlete has a best-corrected visual acuity (BCVA) of better than 20/40 in the worse eye. These athletes could experience a significant disability if the better eye is seriously injured, as can those athletes with the loss of an eye. Athletes who have previously undergone eye surgery or who have had a serious eye injury may be at increased risk of injury because of weakened eye tissue. Use of eye guards approved by ASTM International (formerly the American Society for Testing and Materials [ASTM]) and other protective equipment may allow the athlete to participate in most sports, but this approach must be judged on an individual basis. Qualified yesFever§Fever can increase cardiopulmonary effort, reduce maximum exercise capacity, make heat illness more likely, and increase orthostatic hypotension during exercise. In rare cases, fever may accompany myocarditis or other infections that may make exercise dangerous. NoHeat illness, history ofBecause of the increased likelihood of the recurrence of heat illness, the athlete needs an individual assessment to determine the presence of predisposing conditions and to arrange a prevention strategy. Qualified yesHuman immunodeficiency virus (HIV) infection§Because of the apparent minimal risk to others, all sports may be played, as allowed by the patient's state of health. In all athletes, skin lesions should be properly covered, and athletic personnel should use universal precautions when handling blood or body fluids with the presence of visible blood. YesKidney, absence of oneThe athlete with 1 kidney needs individual assessment for contact/collision and limited contact sports.Qualified yesLiver, enlargedIf the liver is acutely enlarged, athletic participation should be avoided because of a risk of rupture. If the liver is chronically enlarged, individual assessment is needed before contact/collision or limited contact sports are played. Qualified yesMalignancy*The athlete needs an individual assessment.Qualified yesMusculoskeletal disordersThe athlete needs an individual assessment.Qualified yesHistory of serious head or spine trauma, severe or repeated concussions, or craniotomyThe athlete needs an individual assessment for participation in contact/collision or limited contact sports and also for noncontact sports if deficits in judgment or cognitions are present. Recent research supports a conservative approach to the management of concussions.[3] Qualified yesConvulsive disorder, well controlledThe risk of convulsions during sports participation is minimal.YesConvulsive disorder, poorly controlledThe athlete needs an individual assessment before participation in contact/collision or limited contact sports. Because a convulsion may pose a risk to the athlete or to others, the following noncontact sports should be avoided: archery, riflery, swimming, weight lifting or power lifting, strength training, and sports involving heights. Qualified yesObesityBecause of the risk of heat illness, obese persons need careful acclimatization and hydration.Qualified yesOrgan transplant recipient*The athlete needs an individual assessment.Qualified yesOvary, absence of oneThe risk of severe injury to the remaining ovary is minimal.YesPulmonary compromise, including cystic fibrosis*The athlete needs an individual assessment, but generally, all sports may be played if oxygenation remains satisfactory during a graded exercise test. Patients with cystic fibrosis need acclimatization and good hydration to reduce the risk of heat illness. Qualified noAsthmaWith proper medication and education, only athletes with the most-severe asthma need to modify their participation.YesAcute upper respiratory infectionUpper respiratory obstruction may affect pulmonary function. Athletes, with the exception of those with mild disease, need an individual assessment. (See Fever, above.) Qualified yesSickle cell diseaseThe athlete needs an individual assessment. In general, if the status of the illness permits, the athlete may play all sports except high-exertion, contact/collision sports. Overheating, dehydration, and chilling must be avoided. Qualified yesSickle cell traitIndividuals with the sickle cell trait (AS) are unlikely to have an increased risk of sudden death or other medical problems during athletic participation in most conditions. Exceptions include the most extreme conditions of heat; humidity; and, possibly, increased altitude. Like all athletes, those with the sickle cell trait should be carefully conditioned, acclimatized, and hydrated to reduce any possible risk. YesSkin boils, herpes simplex, impetigo, scabies, molluscum contagiosumDuring the periods in which the patient is contagious, participation in gymnastics with mats, martial arts, wrestling, or other contact/collision or limited-contact sports is not allowed. Herpes simplex virus is probably not transmitted via mats. Qualified yesSpleen, enlarged§Patients with an acutely enlarged spleen should avoid all sports because of the risk of rupture. Those with chronically enlarged spleens need an individual assessment before playing contact/collision or limited-contact sports. Qualified yesTesticle, absent or undescendedAthletes in certain sports may require a protective cup.YesNote: This table is designed to be understood by medical and nonmedical personnel. In the Explanation column, a notation that the athlete needs an evaluation means that a physician with appropriate knowledge and experience should determine whether an athlete with the listed medical condition can safely participate in a given sport. Unless otherwise noted, these evaluations are generally recommended because of variations in the severity of disease and in the risk of injury in specific sports.[7] *Not discussed in text of the AAP source monograph.

†See Table 4 above.

‡Mild, moderate, and severe congenital heart disease are defined elsewhere (26th Bethesda Conference, Med Sci Sports Exerc, 1994).[8]

§See the APP recommendation[7] as indicated for qualifications by other commentators.

PreviousNextDisqualification From Sports Participation and Its Implications

The decision to disqualify an athlete from sports participation is made in light of the specific sport for which the individual seeks medical clearance to participate. When the situation is vague, the guidelines described above (see Clearance for Sports Participation) can help in clinical decision making about granting clearance.

The AAP guidelines[7] are broad and not specific in many areas. If obscure cardiac defects are detected, the current criterion standard for decision making is the 26th Bethesda Conference on cardiac anomalies and participation in sports.[8] Articles by Torg[9, 10] are often referenced, as well as those of Torg et al[11, 12, 13] for cases involving congenital or acquired cervical spinal deformities. Fortunately, obscure conditions that may require such referencing are rare, and usually, a general guideline like that of the AAP is most often used. This resource is valuable because the associated categorizations (contact and intensity) can be used to make recommendations for the athletes that are denied sports participation.

A pitfall to keep in mind is discouraging athletes from general sports participation when they are disqualified from a particular sport; athletes might still be able to compete in other sports and experience the benefits of participation. Furthermore, an optimistic approach is always important when problems are detected in young and impressionable athletes. Many disqualifying conditions can be resolved or controlled with medical or surgical intervention, enabling future sports participation.

In a study by Rifat et al[14] , the authors showed that the great majority of disqualifications as a result of athletic preparticipation evaluations involved the following 7 findings:

Dizziness with exerciseAsthma historyUnfavorable body mass indexSystolic BP elevationVisual acuity defectPresence of a heart murmurMusculoskeletal abnormality

However, many of these conditions were further evaluated and deemed low risk, and clearance was eventually granted to the affected athletes.

Other conditions can be treated with medical intervention, and the athlete may eventually return to the sport. Other athletes can be redirected to different sports in which they can have a good and safe athletic experience.

PreviousNextConclusion

An athletic preparticipation evaluation can be performed efficiently and thoroughly when protocols and tools are in place. Use of a reliable medical history questionnaire and a good screening physical examination are usually adequate to meet these needs. The following issues should always be emphasized:

Demographic data (eg, name, age, sex, sport, telephone numbers, current medications, allergies to medications)History of exercise-induced loss of consciousnessFamily history of sudden cardiac deathHistory of poorly controlled asthmaHistory of recent or previous concussionsHistory of fractures or major musculoskeletal problemsHistory of heat strokeHistory of environmental anaphylactic reactions, as with insect bitesHistory of loss or dysfunction of 1 of a pair of organsHistory of chronic illness requiring regular physician interventionHistory of drastic weight changeFor females only – First menstrual period, menstrual irregularity, last menstrual periodParental signature on history forms for minors

A focused physical examination should emphasize the following:

Vital signs (eg, height, weight, BP)Visual acuityInfectious dermatosesAnisocoriaWheezingHeart murmurs or irregular heart rhythmsAbdominal organomegaly

If abnormalities are detected during the physical examination, further workup should be pursued as indicated.

Finally, the participation status of the athlete for the specific sport should be determined. The main goals of the athletic preparticipation evaluation are as follows:

To discover any abnormalities that places the individual at sport-specific risk of injuryTo inform the athlete of correctible abnormalities before the start of the sport's seasonTo determine the safety of the athlete's participationTo provide a database that team physicians, coaches, and administrators can use for referenceTo provide a platform of interaction between athletes and physicians

Participation in sports is a benefit to which everyone is entitled. Ensuring an athlete's safety can promote a healthy lifelong habit of physical activity in which the athlete can learn about discipline, teamwork, physical fitness, and camaraderie.

Previous, Sports Physicals

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Female Athlete Triad

Background

With the increase in female participation in sports (much of it attributable to Title IX legislation in the United States),[1, 2] the incidence of a triad of disorders particular to women—the so-called female athlete triad—has also increased.

The female athlete triad, though more common in the athletic population, can also occur in the nonathletic population. However, even though this triad was first described at the 1993 meeting of the American College of Sports Medicine (ACSM),[3, 4] associations between bone mineral density (BMD), stress fractures, eating disorders, and female athletics had been observed for decades before the syndrome was formally named.

The components of the female athlete triad, as put forth by the 1997 ACSM positional stand, consisted of disordered eating, amenorrhea, and osteoporosis.[5] Not all patients have all 3 components of the triad, and newer data suggest that even having only 1 or 2 elements of the triad greatly increases these females’ long-term morbidity.

In addition, a study by Burrows et al has suggested that the current triad components do not identify all at-risk women; rather, the authors suggest that criteria such as exercise-related menstrual alterations, disordered eating, and osteopenia may be more appropriate.[6]

Subsequent research on the female athlete triad culminated in an updated definition published by ACSM in 2007. The 2007 ACSM positional stand looks at each disorder as a point on a continuous spectrum rather than as a severe pathologic endpoint, as follows[7] :

“Disordered eating” has been replaced by a spectrum ranging from “optimal energy availability” to “low energy availability with or without an eating disorder” “Amenorrhea” has been replaced by a spectrum ranging from “eumenorrhea” to “functional hypothalamic amenorrhea” “Osteoporosis” has been replaced by a spectrum ranging from “optimal bone health” to “osteoporosis”

The 2007 ACSM positional stand also emphasizes that energy availability is the cornerstone on which the other 2 components of the triad rest.[7] Without correction of this key component, full recovery from the female athlete triad is not possible.

Often difficult to recognize, the female athlete triad can have a significant impact on morbidity and even mortality in a relatively young segment of the population. Indeed, the full impact of this syndrome may not be realized until these women reach menopause, when bone loss is accelerated.

Significant research of the triad has been ongoing, and emerging data may expand the female athlete triad to a tetrad.[8, 9] This additional research has been examining the relationship of the triad to endothelial dysfunction and the possible increased cardiac risk it athletes may face.[8, 9]

NextPathophysiologyReduced energy availability

The first component of the female athlete triad, energy availability,[7, 10] is defined as “dietary energy intake minus exercise energy expenditure” and is intended to capture those athletes who may have eating and weight concerns but do not have “significant psychopathology” and do not meet the criteria for disordered eating.

The term disordered eating itself was coined to include pathologic eating behaviors that do not meet the strict Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) requirements for anorexia or bulimia; thus, it includes, but is not limited to, anorexia nervosa and bulimia nervosa.

Indeed, disordered eating includes a spectrum of behaviors ranging from simple failure to take in enough food to offset energy expenditure to preoccupation with eating and a profound fear of becoming fat (typically expressed by instituting measures such as food restrictions or the use of diet pills, laxatives, or diuretics).

Menstrual dysfunction

The second component of the triad, menstrual dysfunction,[7] describes the spectrum of menstrual function from eumenorrhea to amenorrhea and enables clinicians to capture a large portion of athletes who may have low estrogen levels but who still experience menstruation.

Menstrual dysfunction includes luteal suppression, anovulation, oligomenorrhea, and primary and secondary amenorrhea. Luteal suppression is marked by a shortened luteal phase and a prolonged follicular phase in which estradiol levels decrease. The cycle length usually does not change; the athlete will continue to ovulate—although it may be later in the cycle—and usually has regular menstruation.

Anovulation is marked by low levels of estradiol and progesterone, which deter follicular development, as well as by an absence of ovulation. Although the circulating hormone levels are decreased, female athletes will often menstruate, some experiencing shortened or prolonged cycles because of the stimulation of their uterine lining by the low levels of estradiol. Oligomenorrhea is defined as “greater than 35 days between cycles.”

Amenorrhea usually refers to secondary amenorrhea, though delayed menarche (primary amenorrhea) can occur in young athletes. By consensus, secondary amenorrhea is defined as the “absence of menstrual cycles lasting more than 3 months after menarche has occurred.” Physicians are cautioned that a full workup should be completed to rule out any other causes of menstrual dysfunction before such dysfunction is attributed to low estradiol levels stemming from low energy availability.[11]

Impaired bone health

The final component of the female athlete triad, bone health,[7, 12] describes a continuum extending from optimal bone health to osteoporosis and focuses on bone strength, which consists of BMD (or bone mineral content) and bone quality.

Bone quality refers to factors related to bone turnover rates (eg, resorption versus formation, microarchitecture or trabeculae, time for maturation of the new bone matrix, and bone geometry and size). Our current inability to measure bone quality leaves one half of the equation for bone health empty and offers an explanation for why some athletes with the same poor BMDs as their colleagues may suffer more fractures. Therefore, dual-energy x-ray absorptiometry is used as a quantitative measure of bone health.

When reporting BMD, T-scores are used for the diagnosis of osteopenia and osteoporosis. However, the T-score measures the standard deviations (SDs) below the mean to predict fracture risks for postmenopausal woman. Concern over mislabeling of our premenopausal athletes, adolescents and children, led the International Society for Clinical Densitometry (ISCD) to issue a positional stand in 2004.[12]

The ISCD’s recommendation is to determine BMD by comparing chronologic age and sex using a Z-score distribution. The Society further recommends that the term osteopenia not be used in describing bone density and that the term osteoporosis be reserved for “low BMDs” with secondary clinical risk factors such as “chronic malnutrition, eating disorders, hypogonadism, glucocorticoid exposure, and previous fractures.”[12]

Athletes with a Z-score 2 SDs below the mean are to be termed “low bone density below the expected range for age” if they are premenopausal women and “low bone density for chronologic age” if they are children. The 2007 ACSM positional stand further defined “low BMD” as “a history of nutritional deficiencies, hypoestrogenism, stress fractures, and/or other secondary clinical risk factors for fracture together with a BMD Z-score between –1.0 and –2.0” and osteoporosis as “secondary clinical risk factors for fracture with a Z-score ≤ –2.0.”[7]

Because most athletes already have a higher BMD than nonathletes, the ACSM also recommends that physicians consider performing further workup for any athlete with a BMD Z-score below -1.0, even in the absence of fracture.[7]

The bones of the lower extremities, pelvis, and vertebrae are the ones most commonly affected by poor bone health in women with the female athlete triad; stress and frank fractures of these areas are the typical manifestations. Peak bone mass is obtained between the ages of 20 and 30 years, with peak bone mineral content reached between the ages of 9 and 20 years.

Menstruating athletes gain approximately 2-4% of bone mass per year, whereas amenorrheic athletes tend to lose 2% of BMD per year. Thus, it is easy to see why athletes who are involved in high-impact sports can still be more susceptible to fractures than their nonathletic and menstruating athletic counterparts. Often these fractures are due to the increased stress sustained by these bones in the course of physical activity. In this respect, athletes with the female athlete triad are not unlike their healthy counterparts. However, those who have the triad or portions of it are more susceptible to multiple fractures, and they are also more likely to sustain fractures in larger, less commonly affected bones (eg, femoral neck, pelvis, and vertebrae).

Endothelial dysfunction

Ongoing research is looking at athletes diagnosed with the female athlete triad and the link to their endothelial dysfunction. Exact pathophysiology and etiology have yet to be established, but repeated studies have shown many athletes with the triad have endothelial dysfunction, which is a strong predictor of coronary artery health and a possible increase in atherosclerotic disease and cardiovascular event rates.[8, 9]

PreviousNextEtiology

The theory behind the female athlete triad is that this syndrome is caused by an energy drain or caloric deficit (ie, the athlete’s energy expenditure exceeds her dietary energy intake).[7, 10] This low energy availability, whether subconscious or conscious, disrupts the hypothalamic-pituitary-ovarian axis, resulting in decreased gonadotropin-releasing hormone (GnRH) pulsatility and low luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels.[13]

These changes eventually lead to decreased estrogen production, causing menstrual dysfunction. The decreased estrogen levels, in turn, affect calcium resorption and bone accretion, causing decreased bone health.

Studies have indicated that 30 kcal/kg of lean body mass is a crucial threshold for maintaining menstrual function[7] ; they have also demonstrated that increasing exercise drastically while covering the energy expenditure with increased caloric intake did not result in disruption of LH pulsatility. Conversely, decreasing an athlete’s caloric intake to less than 30 kcal/kg within 5 days resulted in decreased LH pulsatility. All of these findings support the energy drain theory.

The hormone leptin, which is secreted by adipocytes, has also garnered increased interest. Leptin appears to influence the metabolic rate, and levels are proportional to body mass index (BMI). It may be a significant mediator of reproductive function, and many studies have demonstrated that low levels of leptin correlate positively with amenorrhea and infertility. Furthermore, leptin receptors have been found on hypothalamic neurons involved in the control of GnRH pulsatility and in bone, which may also affect osteoblastic function.

Athletes in some sports that are linked to an aesthetic component or a weight class are more likely to develop the female athlete triad. These athletes often attempt to reach unrealistic weight and body fat goals dictated by their sport, to the detriment of their health.[14, 15, 16, 17]

Emotional stressors can also often be identified as inciting factors in athletes with the triad. The death of a coach or a family member, growth spurts, an illness that prevents training, and other events that an athlete cannot control often lead to disordered eating and excessive training—areas of life that the athlete can control.

For many, moving to a university setting initiates the triad cascade. Some young women move far away from family and friends, and they may carry the added responsibilities of a sports scholarship and a demanding academic workload. Collegiate athletes have the additional pressure of performing to higher competitive standards with a new coach and trainer and alongside athletes who may have had 2-3 years more experience. Not surprisingly, the prevalence of the female athlete triad suddenly increases in college freshmen.

PreviousNextEpidemiology

As noted (see above), though all female athletes are at risk for the female athlete triad or any of its components, sports that have an aesthetic component (eg, ballet, figure skating, or gymnastics) or are tied to a weight class (eg, tae kwon do, judo, or wrestling) have a higher prevalence of affected female athletes.[7, 14, 15, 18, 19]

Obtaining exact epidemiologic data is difficult because of the lack of reporting or gathering of data from athletes. Like individuals with anorexia or bulimia, many athletes with the triad try to hide their symptoms or behavior from friends, family, trainers, or coaches. This is the main reason why diagnosis is so difficult. In fact, the vast majority of cases are diagnosed only after advanced symptoms become apparent. Milder cases may be extremely difficult to diagnose if the physician does not already have a high degree of suspicion.[7, 20, 21, 22, 23]

The prevalence of low energy availability in female athletes is difficult to assess. Multiple factors (eg, the difficulty of gathering accurate caloric intake data from athletes, inability to measure energy expenditure, uncertainty regarding which sports to include or which eating attitude survey to use, and varying definitions of eating disorders) compound the issue.

It is known, however, that an athlete is at increased risk for the spectrum of reduced-to-low energy availability, with or without an eating disorder, if she has a comorbid psychological disorder, such as anxiety, depression, or obsessive compulsive disorder (OCD). In some studies, the incidence of disordered eating in the female athletic population has been estimated to be as high as 62%, with the incidence of anorexia nervosa and bulimia (as defined in DSM-IV) estimated at 4-39%.

The prevalence of menstrual dysfunction is also difficult to assess. Over a number of studies, it has ranged from as low as 6% to as high as 79%, depending on the sport studied, the patient’s age, the definition and assessment of menstrual dysfunction, the use of oral contraceptives, the training volume, and the presence of subclinical menstrual disorders, such as luteal suppression and anovulation. Studies continue to be performed, and it is hoped that more and better data will become available.

The prevalence of impaired bone health, as indicated by reduced BMD, is likewise difficult to assess because of the prohibitively high cost of DXA scans. Osteopenia has been reported to occur in 22-50% of athletes, compared with 12% of nonathletes. Osteoporosis has also been reported in 0-13% of athletes, compared with 2.3% of nonathletes. Now that the ISCD has recommended using Z-scores instead of T-scores, more research will have to be done to obtain accurate data for athletes.

Although good epidemiologic data regarding the female athlete triad are not yet available, there is reason to hope that this will change in the near future. In the meantime, many preparticipation physical questionnaires now include questions about whether the athlete is satisfied with her current weight and about how much weight she would like to gain or lose. Simple inquiries such as these may reveal the first warning signs of the female athlete triad.

PreviousNextPrognosis

For many athletes, the long-term prognosis is good. Few athletes with the female athlete triad are admitted to the hospital for inpatient treatment, and few die from their disease. However, significant long-term morbidity may affect these women later in life.

The diagnosis of the female athlete triad was established in the early 1990s, although this set of symptoms had been noted for years before it was named.[3, 16, 24, 25] However, no long-term data on future problems are available. The first generation of athletes in whom this condition was diagnosed is still years away from menopause. Thus, it is unclear whether osteoporosis occurring at a younger age affects mortality or leads to more advanced osteoporosis later in life or to an increased risk of significant fractures (eg, hip fractures).

For mild to moderate cases of the female athlete triad, some improvement in bone health is thought to occur. The lost BMD is unlikely to be replaced in its entirety, and the bone mass that should have been accumulated during this important time in bone development may or may not be regained. However, many case reports show that bone density does not increase, suggesting that losses may be permanent. Unfortunately, no long-term, double-blind, controlled studies are available (or even performable).

As more information about the female athlete triad and its complications is gathered, everyone involved may better understand the significant morbidity that can occur years or decades after the disease is diagnosed and treated.

PreviousNextPatient Education

Educating athletes may lead to earlier detection of the female athlete triad. If women know that amenorrhea is not a positive sign of hard work but a harbinger of disease, they may seek treatment sooner. Of course, the triad has a secretive nature, and by the time an athlete shows signs of disordered eating, education may not be enough to help these women seek help. If the general athletic population is aware of the signs and symptoms of this disease, the female athlete triad might be caught in its early stages.

Physicians need to do better in educating trainers, coaches, and parents (as well as the athletes themselves). These are the people who will have daily contact with the athlete, and they may be the persons who first raise concerns about a particular individual. Taking the time to talk to the athletic staff about the warning signs may help in preventing the disease or catching it in its early stages.

For patient education resources, see the Osteoporosis and Bone Health Center, the Exercise, Nutrition, and Weight Management Center, and the Women’s Health Center, as well as Anorexia Nervosa, Bulimia, and Amenorrhea.

PreviousProceed to Clinical Presentation , Female Athlete Triad

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Exercise-Induced Asthma

Practice Essentials

Exercise-induced asthma is a condition of respiratory difficulty (bronchoconstriction) that is related to histamine release,[1, 2, 3] is triggered by aerobic exercise, and lasts several minutes. Causes include medical conditions, environmental factors, and medications.[4]

Essential update: American Thoracic Society guidelines for exercise-induced bronchoconstriction

The American Thoracic Society has developed new evidence-based practice guidelines for individuals with exercise-induced bronchoconstriction. These guidelines address its diagnosis, management, and environmental triggers, as well as considerations in elite athletes.[5]

The recommendations in managing exercise-induced bronchoconstriction include the following:

Preexercise administration of an inhaled short-acting beta-agonist (SABA) (about 15 minutes before exercise)Use of a daily inhaled corticosteroid, a daily leukotriene receptor antagonist, or a mast cell stabilizing agent before exercise for patients who continue to exhibit symptoms despite administration of SABA therapy or who require daily or more frequent SABA use Interval or combination warm-up exercise before planned exercise for all patients with exercise-induced bronchoconstriction

Daily use of an inhaled long-acting beta-agonist (LABA) or an inhaled corticosteroid is not recommended as monotherapy in patients with symptoms despite SABA therapy or in patients who require daily or more frequent SABA use.[5]

Signs and symptoms

Symptoms of exercise-induced asthma during or following exercise include the following[1, 3] :

Chest tightness or painCough, shortness of breath, wheezingUnderperformance or poor performance on the field of playFatigue, prolonged recovery timeGastrointestinal discomfort

See Clinical Presentation for more detail.

Diagnosis

The patient's physical examination is often unremarkable in the clinical setting but may have a higher yield on the field or after an exercise challenge.[6]

Examination should include the following areas:

Skin: Note any signs of atopic diseaseHead, ears, eyes, nose, and throat: Note any evidence of acute infection, chronic infection, or allergic/atopic diseasePharynx: Note any mucus, cobblestoning, and/or erythemaNose: Note presence of enlarged turbinates, erythema, and/or congestionSinuses: Note presence of tendernessLungs: Note presence of rales, rhonchi, wheezes, and/or prolonged expiratory phaseHeart: Note presence of murmurs and/or an irregular rhythm

Laboratory tests

Exercise-induced asthma is generally a clinical diagnosis. Laboratory evaluation is usually reserved for equivocal cases, for treatment failures, and to narrow the differential diagnosis.

Laboratory studies used to assess for allergy and infection include the following:

Complete blood count: To determine likelihood of infection and to evaluate eosinophil counts (for allergy)Immunoglobulin E levels, with/without nasal swab for eosinophils: To determine likelihood of allergic diseaseSkin allergen testing/radioallergosorbent test: To help identify specific allergensErythrocyte sedimentation rate or C-reactive protein levels: To evaluate for inflammatory and infectious conditionsSputum analysis and culture: To help identify presence of infection and treatment options for strains of resistant organismsThyroid function tests: To evaluate for thyroid dysfunction if anxiety is suspected of mimicking asthma symptoms

Challenge testing to formalize the diagnosis of exercise-induced asthma includes the following:

Treadmill exercise challenges with preexercise and postexercise pulmonary function levelsInformal exercise challenge: Substitutes for treadmill exercise challenge; heart rate not monitored, and level of work not reliable Pulmonary function testing: To evaluate baseline pulmonary function or allergic asthma; to categorize pulmonary function as obstructive or restrictive disease Bronchoprovocation testing: Positive results indicative of general asthma rather than specific for exercise-induced asthmaEucapnic voluntary hyperventilation: Sensitive and accurate for diagnosis of exercise-induced asthma[7, 8] ; can be applied in a laboratory setting and altered to mimic the environmental conditions of the patient’s specific sport

Imaging studies

Imaging studies are often not indicated in the evaluation of routine exercise-induced asthma. However, the following radiologic studies may be useful for assessing other possibilities in the differential diagnosis: Chest radiography: To evaluate for signs of chronic lung disease (eg, hyperexpansion, scarring, fibrosis, hilar adenopathy), for congestive heart failure and/or valvular heart disease (eg, chamber enlargement, pulmonary edema, vascular or valvular calcification), and for a foreign body Lateral neck radiography/soft-tissue penetration: To evaluate the upper airway for a foreign body or obstructionEchocardiography: To evaluate for cardiac valvular abnormality or global contractile function, as well as dysrhythmia, cardiomegaly, or other heart disease that may manifest during exercise

Procedures

Laryngoscopy can be performed to evaluate for foreign body or other obstruction in the upper airway. Postexercise laryngoscopy can be used to evaluate for vocal cord dysfunction, a condition often mistaken for exercise-induced asthma.

See Workup for more detail.

Management

Treatment of the athlete who is experiencing an acute attack of exercise-induced asthma is the same as in any asthma attack situation and includes immediately removing the patient from competition or play.

The optimal treatment for exercise-induced asthma is to prevent symptomatic onset. After controlling the patient's underlying and contributing factors (eg, respiratory infection, allergy, allergic asthma), a combination of drugs can be used to prevent this condition.[1]

Pharmacotherapy

The basis of treatment for exercise-induced asthma is with preexercise short-acting beta2-agonist administration.[1] There is less of a role for traditional asthma medications (eg, corticosteroids, theophylline) in managing pure exercise-induced asthma.

The following medications are used in the treatment of exercise-induced asthma:

Short-acting beta2-adrenergic agonists (eg, albuterol, pirbuterol, levalbuterol)Long-acting beta2-adrenergic agonists (eg, salmeterol, formoterol)Mast cell stabilizers (eg, cromolyn sodium)Inhaled corticosteroids (eg, flunisolide, beclomethasone dipropionate, ciclesonide, fluticasone, budesonide)Xanthine derivatives (eg, theophylline)Leukotriene receptor antagonists (eg, zafirlukast, montelukast)5-Lipoxygenase inhibitors (eg, zileuton)Adrenergic agents (eg, epinephrine)

Other approaches

Nonpharmacologic measures in the treatment of exercise-induced asthma include the following:

Sports selectionAltering breathing techniques (eg, predominant mouth breathing to nasal breathing)Coordination and timing of warm-up techniques, medication, and competition

See Treatment and Medication for more detail.

[#Treatment] Image library

Asthma treatment. Asthma causes and symptoms. Antigen presentation by the dendritic cell with the lymphocyte and cytokine response leading to airway inflammation and asthma symptoms. NextBackground

Exercise-induced asthma (EIA) is a condition of respiratory difficulty that is related to histamine release,[1, 2, 3] triggered by aerobic exercise, and lasts several minutes (see Pathophysiology). Causes include medical conditions, environmental factors, and medications (see Etiology).[4]

Symptoms of EIA may resemble those of allergic asthma, or they may be much more vague and go unrecognized, resulting in probable underreporting of the disease (see Clinical Presentation). The optimal treatment for EIA is to prevent the onset of symptoms, and the basis of treatment is with preexercise short-acting β2 -agonist administration.[1] Long-acting β2 -agonists and mast cell stabilizers, as well as antileukotriene drugs have also been shown to be effective (see Treatment and Management).[9, 10]

With proper interventions, the prognosis is excellent for athletes with asthma. Most symptoms can be prevented, and performance should not be limited by EIA with proper treatment (see Prognosis).

Exercise-induced urticaria, or exercise-induced anaphylaxis, is often presumed to be related to EIA, even though this condition is extremely rare and unrelated (see Diagnostic Considerations).

Go to Asthma, Pediatric Asthma, Exercise-Induced Anaphylaxis, Angioedema, and Urticaria for more information on these topics.

PreviousNextAnatomy

The problem with the functional anatomy in exercise-induced asthma (EIA) occurs distal to the glottis, in the lower airway. Bronchoconstriction is involved that is distinguishable from laryngospasm, which can occur in other exercise-related conditions. One such example is the condition known as vocal cord dysfunction in which there is paradoxical narrowing of the vocal cords during inspiration, resulting in stridor that is often misconstrued as audible wheezing.[11, 12] Normally, the vocal cords open with inspiration. (Go to Vocal Cord Dysfunction for more information on this topic.)

PreviousNextPathophysiology

EIA usually affects individuals who participate in sports that include an aerobic component. The condition can be seen in any sport, but EIA is much less common in predominantly anaerobic activities. This is likely due to the role of consistent and repetitive air movement through the airways (seen in aerobic sports), which affect airway humidity and temperature. EIA triggers an unknown biochemical and neurochemical pathway, resulting in the bronchospasm, which manifests as the symptoms of the disease.

Although the exact mechanism of EIA is unknown, there are 2 predominant theories as to how the symptom complex is triggered. One is the airway humidity theory, which suggests that air movement through the airway results in relative drying of the airway. This, in turn, is believed to trigger a cascade of events that results in airway edema secondary to hyperemia and increased perfusion in an attempt to combat the drying. The result is bronchospasm.

The other theory is based on airway cooling and assumes that the air movement in the bronchial tree results in a decreased temperature of the bronchi, which may also trigger a hyperemic response in an effort to heat the airway. Again, the result is a spasm in the bronchi.

Many authors believe there may be a combination of the above 2 theories that takes place, but the biochemical or physical pathways that mediate these responses are unclear. Evidence may even exist to support the idea that the resulting cascades are not the inflammatory pathways to which we attribute allergic asthma.

Likewise, certain sports and their environments predispose individuals with asthma to experience EIA. Sports played in cold and dry environments usually result in more symptom manifestation for athletes with this condition. On the other hand, when the environment is warm and humid, the incidence and severity of EIA decrease.

Also see the figure below.

Asthma treatment. Asthma causes and symptoms. Antigen presentation by the dendritic cell with the lymphocyte and cytokine response leading to airway inflammation and asthma symptoms. PreviousNextEtiology

The causes of EIA can be divided into the categories of medical, environmental, and drug related. Eliminating some causes can diminish—but may not eliminate—the athlete's symptoms. EIA may also exist without the presence of any of these causes.

Medical conditions

Poorly controlled asthma results in increased patient symptoms with exercise. Maximizing control of the patient's baseline asthma, when present, is critical in the treatment of EIA.[1] In addition, poorly controlled allergic rhinitis also results in increased patient symptoms with exercise, and secretions resulting from hay fever can aggravate both allergic asthma and EIA.

Viral, bacterial, and other forms of upper respiratory infections also aggravate the symptoms of EIA. Controlling the secretions of these illnesses, as with allergic rhinitis, can make the EIA symptoms much more tolerable.

Environmental factors

Excess of pollens or other allergens in the air can exacerbate the allergic and exercise-induced forms of asthma. Pollutants in the air are irritants to the airways and can lower the threshold for symptomatic bronchospasm.

The chemicals used in certain sports for environmental maintenance can predispose individuals to wheezing and worsen EIA symptoms. These chemicals include the following:

Chlorination in poolsInsecticides and pesticides used to maintain playing fieldsFertilizers and herbicides used to maintain playing fieldsPaints and other decorative substances to enhance the appearance of playing fieldsAsthmogenic agents

Certain medication classifications and specific drugs can provoke or exacerbate bronchial reactivity in EIA, such as the following:

β-blockersAspirinNonsteroidal anti-inflammatory drugs (NSAIDs)DiureticsZanamivirPreviousNextEpidemiology

EIA affects 12-15% of the population. Ninety percent of asthmatic individuals and 35-45% of people with allergic rhinitis experience EIA, but even when those with rhinitis and allergic asthma are excluded, a 3-10% incidence of EIA is seen in the general population.[3]

EIA seems to be more prevalent in some winter or cold-weather sports.[13] Some studies have demonstrated rates as high as 35% or even 50% in competitive-caliber figure skaters, ice hockey players, and cross-country skiers.[14, 7]

PreviousNextPrognosis

The prognosis is excellent for athletes with asthma. With proper interventions, most symptoms can be prevented, and performance should not be limited by EIA if this condition is treated properly. Newly diagnosed young athletes need to be educated that this condition should not be perceived as an insurmountable disability. Using examples of the numerous elite athletes (eg, Jackie Joyner-Kersee [track and field Olympian]; Amy Van Dyken [Olympic swimmer]; Jerome Bettis [former running back for the Pittsburgh Steelers]) with this condition can help young impressionable athletes continue in their endeavors without fear of failure or medical distress.

PreviousNextPatient Education

Patient education is a critical part of the treatment of EIA. Once the diagnosis is made, athletes should be encouraged to continue in their activities with the reassurance that proper treatment can allow for an unhampered performance for most individuals.

In addition to reassurance, it is also important to teach individuals to recognize the signs of an impending attack. Once recognized, individuals should be taught to remove themselves from the aggravating activity and initiate treatment as necessary. This includes education about the proper choice of agents to abort an acute attack (ie, albuterol), but not cromolyn, salmeterol, or an inhaled steroid.

Teaching the proper mechanics of inhalant medication administration is also important, along with, if needed, teaching and demonstrating the proper use of a spacer device to the patient; without the proper mechanics in using such devices, the medication does not reach the area of pathology and does not benefit the athlete.

Education of the coaching staff is also crucial, because coaches need to know that shortness of breath in athletes does not always indicate poor conditioning and that the consequences of ignoring an asthma attack can be serious.

For patient education information, see the Asthma Center, as well as Asthma, Asthma FAQ, and Exercise-Induced Asthma.

PreviousProceed to Clinical Presentation , Exercise-Induced Asthma

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Knee Osteochondritis Dissecans

Background

Osteochondritis dissecans (OCD), by definition, is a disorder of one or more ossification centers, characterized by sequential degeneration or aseptic necrosis and recalcification. OCD lesions involve both bone and cartilage. These lesions differ from acute traumatic osteochondral fractures; however, they may manifest in a similar fashion. OCD lesions also must be differentiated from meniscal pathology. OCD causes 50% of loose bodies in the knee. The etiology of these lesions is multifactorial, including trauma, ischemia, abnormal ossification centers, genetic predisposition, or some combination of these factors. Little agreement exists among researchers regarding the etiology of OCD.

Images of osteochondritis dissecans of the knee are provided below:

Anteroposterior and lateral radiographs of medial femoral condyle osteochondritis dissecans. Anteroposterior radiograph of medial femoral condyle osteochondritis dissecans. Arthroscopic view of medial femoral condyle osteochondritis dissecans, hinged medially. Note the large size and thickness of the fragment. Arthroscopic view of osteochondritis dissecans of the medial femoral condyle. The osteochondral fragment has been elevated from the crater. Note the sclerotic crater with an interposed fibrocartilaginous layer. This lesion has been previously treated with drilling; an old drill hole can be seen faintly at the upper aspect of the crater. Arthroscopic debridement of the osteochondritis dissecans bed to bleeding bone. Replacement of the fragment and temporary Kirschner wire stabilization. Completed osteochondritis dissecans stabilization with 2 Herbert screws. On initial examination, the most lateral defect was comminuted and removed; the larger weight-bearing surface was maintained and stabilized.

In 1558, Ambroïse Paré removed loose bodies from a knee joint. In 1870, Paget described quiet necrosis within the knee. In 1888, König coined the term "osteochondritis dissecans." He proposed this condition was caused by spontaneous necrosis due to trauma.

With the advent of roentgenography, osteochondrotic conditions in other joints, primarily the hip, were recognized. In 1910, Legg, Calvé, and Perthes independently identified a condition of the hip joint in children, which is now known as Legg-Calvé-Perthes disease. In 1921, Waldenström introduced the term coxa plana (ie, disintegration of capital femoral epiphysis.)

Since the introduction of radiography, 50 additional anatomic sites within the body where OCD can occur have been identified.

Recent studies

Tabaddor et al evaluated the efficacy and safety of poly 96L/4D-lactide bioabsorbable copolymer fixation for unstable OCD in 24 adolescents (mean age, 14.4 y). Plain films at an average of 19.2 months after surgery showed interval healing in 9 patients, no significant change in 1, complete healing in 13, and loose bodies with no interval healing in 1. MRIs showed interval healing in 16 of 17 knees at a mean follow-up of 22.4 months.[1]

Pascual-Garrido et al examined the outcomes of surgical procedures for osteochondritis dissecans in 46 adult patients (48 knees), with patients ranging in age from 20 to 49 years. Patients who were treated with surgical cartilage procedures showed durable function and symptomatic improvement at a mean of 4 years follow-up. Patients treated with arthroscopic reduction and internal fixation and loose-body removal had greater improvement in outcome scores than those treated with an osteochondral allograft. Seven knees required revision procedures at a mean follow-up of 14 months.[2]

Adachi et al evaluated the functional and radiographic outcome of retroarticular drilling without bone grafting in 12 patients with juvenile osteochondritis dissecans after 6 months of unsuccessful nonoperative treatment. The mean Lysholm score significantly improved postoperatively (from 72.3 to 95.8). All lesions except 1 healed after retroarticular drilling, and healing was achieved at a mean of 4.4 months on plain radiographs and 7.6 months on magnetic resonance imaging.[3]

Kijowski et al retrospectively compared the sensitivity and specificity of previously described magnetic resonance imaging criteria for the detection of instability in patients with juvenile or adult osteochondritis dissecans of the knee, with arthroscopic findings as the reference standard. Separately, previously described MR imaging criteria for detection of OCD instability were 0-88% sensitive and 21-100% specific for juvenile OCD lesions and 27-54% sensitive and 100% specific for adult OCD lesions. When used together, the criteria were 100% sensitive and 11% specific for instability in juvenile OCD lesions and 100% sensitive and 100% specific for instability in adult OCD lesions. The authors concluded from their findings that previously described MR imaging criteria for OCD instability have high specificity for adult but not juvenile lesions of the knee.[4]

NextEpidemiologyFrequencyUnited StatesThe average age at presentation is 10-20 years, but osteochondritis dissecans may occur in persons of any age group.The male-to-female ratio is 2-3:1.Bilateral involvement is noted in 30-40% of cases.In 85% of cases, lesions are observed on the medial femoral condyle (MFC) of the knee; 15% of cases are observed on the lateral femoral condyle. Of the MFC lesions, 70% occur in the posterolateral aspect. Of patients with OCD, 21-40% have some history of trauma.International

In Sweden, prevalence is reported at the following levels:

In skeletally immature patients, 150 cases per 250,000 people are reported.In skeletally immature female patients, 18 cases per 100,000 people are reported.In skeletally immature male patients, 29 cases per 100,000 people are reported.PreviousNextFunctional Anatomy

In skeletally immature individuals, the vascularity to epiphyseal bone is very good, supporting both osteogenesis and chondrogenesis. With disruption of the epiphyseal vessels, varying degrees and depth of necrosis occur, resulting in a cessation of growth to both osteocytes and chondrocytes. In turn, this pattern leads to nonspecific changes that produce disordered enchondral ossification, resulting in subchondral avascular necrosis or OCD.

Four stages of OCD have been identified, including revascularization and formation of granulation tissue, osteoclasis of necrotic fragments, intertrabecular osteoid deposition, and remodeling of new bone. With delay in the revascularization stage, an osteochondritis dissecans lesion develops. OCD lesions may lead to articular-surface irregularities, which can cause degenerative arthritic changes.

PreviousNextSport Specific Biomechanics

A proposed cause of OCD is an anatomic variation allowing the lateral aspect of the femoral condyle to abut the tibial spine, leading to repetitive localized epiphyseal microtrauma with osteochondral separation and subsequent OCD. This pattern may lead the patient to walk with the tibia externally rotated to avoid this abutment.

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Meniscus Injuries

Background

Our understanding of the meniscus has changed radically in the last century. In 1887, Sutton described the meniscus as "the functionless remains of a leg muscle."[1] Not until 1948 did Fairbanks appreciate that "meniscectomy is not wholly innocuous," in his classic report of postmeniscectomy radiographic changes.[2] Research and knowledge of the meniscus has continued. The critical importance of the meniscus of the knee joint is now understood.

Note the contrasting images below.

Magnetic resonance imaging scan showing a normal meniscus. Magnetic resonance imaging scan showing a torn medial meniscus.

For patient education resources, see the Foot, Ankle, Knee, and Hip Center and Arthritis Center, as well as Knee Pain and Knee Injury.

NextEpidemiologyFrequencyUnited StatesMeniscal injuries may be the most common knee injury. The prevalence of acute meniscal tears is 61 cases per 100,000 persons.The overall male-to-female incidence is approximately 2.5:1. The peak incidence of meniscal injury for males is in those aged 31-40 years. For females, the peak incidence is in those aged 11-20 years. In patients older than 65 years, the rate of degenerative meniscal tears is 60%. Surgical procedures of the meniscus are performed on an estimated 850,000 patients each year.[3] International

Estimates indicate that at least twice the number of meniscus procedures in the United States are performed worldwide.

PreviousNextFunctional Anatomy

The menisci are 2 semilunar wedges in the knee joint positioned between the tibia and the femur. They are essentially extensions of the tibia that act to deepen the articular surfaces of the otherwise relatively flat tibial plateau to accommodate the relatively round femoral condyles. The superior surfaces are concave and in contact with the femoral condyles; the inferior surfaces are flat and conform to the tibial plateaus. The peripheral, convex borders of the menisci are thick and attach to the joint capsule; the opposite border tapers inward to a thin, free edge centrally. Therefore, menisci have a triangular shape in cross section. Each covers approximately two thirds of the corresponding articular surface of the tibia. The medial and lateral menisci each have distinct, individual anatomic characteristics.[4, 5, 6]

The medial meniscus is semicircular or C-shaped and approximately 3.5 cm in length from anterior to posterior. It is asymmetric with a considerably wider posterior horn than anterior horn. Peripherally, the medial meniscus is continuously attached to the joint capsule, with the middle portion being more firmly attached via connection with fibers of the deep medial collateral ligament. It is anchored to the tibia by the coronary (meniscotibial) ligaments.

The posterior horn of the medial meniscus inserts in the posterior intercondylar fossa directly anterior to the posterior cruciate ligament. The anterior horn attachment is more variable, distributed in a 6- to 8-mm area anterior to the anterior cruciate ligament (ACL) tibial attachment in the anterior intercondylar fossa. Some anterior fibers attach over the anterior periphery of the tibial articular surface, and some posterior fibers of the anterior horn merge with the transverse meniscal ligament that connects to the lateral meniscus.

The lateral meniscus is more nearly circular or O-shaped and covers a larger portion of the tibial plateau surface than the medial meniscus. Its length from anterior to posterior is slightly less than the medial meniscus, and it has an almost uniform width. There is attachment to the joint capsule peripherally, except in the region of the middle one third, where there is no attachment but rather a hiatus for the popliteal tendon.

Unlike the medial meniscus, there is no attachment of the lateral meniscus to the lateral collateral ligament, but the lateral meniscus is anchored to the tibia via coronary (meniscotibial) ligaments. Posteriorly, the lateral meniscus is uniquely attached to the medial femoral condyle by meniscofemoral ligaments. These ligaments are highly variable and pass anterior (ligament of Humphrey) and/or posterior (ligament of Wrisberg) to the posterior cruciate ligament. The posterior attachment to the tibia is just anterior to the medial meniscus attachment in the posterior intercondylar fossa. The anterior horn inserts anterior to the lateral tibial spine and in close proximity to the ACL tibial insertion. Some fibers actually may blend into the ACL.

Despite their attachments, both menisci have mobility. The medial meniscus, with excursion of approximately 5 mm, is half as mobile as the lateral meniscus, whose mobility may exceed 10 mm. The anterior horns are more mobile than the posterior horns. This mobility allows for improved conformity of the tibiofemoral joint. Because the posterior horn of the medial meniscus has the least movement, it is at greatest risk for disruption.

The microanatomy of the meniscus is dense fibrocartilage composed of cells and an extracellular matrix of collagen fibers in network. The cells are termed fibrochondrocytes because they appear to be a mixture of fibroblasts and chondrocytes. These cells are responsible for the synthesis and maintenance of the extracellular fibrocartilaginous matrix.

The most abundant component of the menisci is collagen (75%)—mainly type I collagen (>90%) but it also contains types II, III, V, and VI. Collagen fibers are arranged mostly along a longitudinal or circumferential direction, with some interwoven radial and oblique fibers. The circumferential fibers are related directly to the menisci's functional ability to dissipate compressive loads. The other fibers act primarily as ties to enhance structural rigidity and to help prevent longitudinal splitting. The extracellular matrix also includes proteoglycans, glycoproteins, and elastin.

Most meniscal tissue is avascular and depends on passive diffusion and mechanical pumping to provide nutrition to the fibrocytes within the meniscal substance. Arnoczky and Warren demonstrated the important vascular anatomy of the menisci.[7, 8] The limited peripheral blood supply originates from the medial and lateral inferior and superior geniculate arteries. Branches from these vessels give rise to a perimeniscal capillary plexus within the synovium and joint capsule, which, in turn, supplies the meniscus periphery.

Studies have shown that 10-30% of the periphery of the medial meniscus and 10-25% of the lateral meniscus receives a vascular supply; the remainder receives its nutrition from the synovial fluid from passive diffusion and mechanical pumping. A few terminal branches of these vessels, along with the middle geniculate artery through the synovial covering of the anterior and posterior horn attachments, supply increased vascularity to the meniscal horns. The potential for vascular ingrowth is essential for successful meniscal healing and surgical repair. Various zones of the meniscus are described based on the blood supply; the red zone is the well-vascularized periphery, the red-white zone is the middle portion with vascularity peripherally but not centrally, and the white zone is the central avascular portion.

The neuroanatomy of the meniscus is not well described. However, the distribution of neural elements has been demonstrated in essentially the same anatomic distribution as the vascular supply. The anterior and posterior horns are the most richly innervated, and the body innervation follows the pattern along the periphery. Although not entirely clear, these nerve endings are believed to play a role in sensory feedback and proprioception. The greater innervation of the horns of the meniscus reflects the need for feedback at the extremes of flexion and extension, when the meniscal horns are compressed and neural elements are activated.[4, 5, 6]

The meniscus has unique anatomic properties. An understanding of this anatomy is essential to comprehending its important functions, which include load bearing, load and force distribution, joint stability, joint lubrication, and proprioception.[4, 5, 9] One of the primary functions is to provide load bearing across the knee joint. Fifty percent of the compressive load in the knee is transferred by the menisci in extension, whereas up to 85% of the load is transferred at 90° of flexion. The collagen orientation makes this load bearing possible by converting the compressive forces to tensile forces.

Load and forces are distributed across a much larger surface area because of the menisci, which (1) decrease focal contact pressure by increasing the contact area and (2) protect the underlying articular cartilage. Resection of 15-34% of a meniscus may increase contact pressure by more than 350%. Normal knees have 20% better shock-absorbing capacity than meniscectomized knees.

Joint stability is increased because of meniscal structure, which allows increased congruence and conformity between the femoral condyles and tibial plateaus.[4, 5] The wedge-shaped meniscus attached to the tibia serves as a secondary stabilizer. For example, the posterior horn acts as a shim to resist anterior tibial translation relative to the femur. Meniscectomy alone may not increase knee laxity, but it has been shown that in association with ACL deficiency, anterior laxity is increased. Meniscal lubrication occurs by fluid exudation across the surface, much like articular cartilage.

The classification of meniscal tears provides a description of pathoanatomy. The types of meniscus tears are (1) longitudinal tears that may take the shape of a bucket handle if displaced, (2) radial tears, (3) parrot-beak or oblique flap tears, (4) horizontal tears, and (5) complex tears that combine variants of the above.

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Hamstring Injury

Background

This article focuses on injuries to the hamstring muscles. The word "hamstrings" was derived from the fact that it is these muscles by which a butcher would hang a slaughtered pig.

The hamstrings are a group of muscles (ie, semimembranosus, semitendinosus, biceps femoris) located on the back of the upper leg.[1, 2] The hamstrings are a common source of injury and chronic pain in athletes. Injuries to the hamstring muscles primarily occur proximally and laterally, and they usually involve the biceps femoris. The severity of injury to the hamstring muscles is classified according to the following grades:

Grade 1 is a mild strain, with few muscle fibers being torn.Grade 2 is a moderate strain, with a definite loss in strength.Grade 3 is a complete tear of the hamstrings.

Hamstring injuries almost always occur at the proximal myotendinous junction. In the biceps femoris, this junction extends over most of its entire length. Injury usually does not occur within the tendon itself unless there is preexisting pathology.

Bony avulsion at the ischial origin may occur as well, but this is usually associated with sudden, large-force, hip-flexion injuries.[3] Avulsions are commonly seen in individuals who have been involved in waterskiing accidents in which the knee is extended and the hip is suddenly flexed as the skier falls forward.[4]

One study involving 47 football players with hamstring injuries reported an average of 14 days of convalescence before return to play.

For patient education resources, see the Sports Injury Center, Sprains and Strains Center, and Foot, Ankle, Knee, and Hip Center, as well as Muscle Strain and Ruptured Tendon.

Related Medscape topics:

Resource Center Adolescent Medicine

Resource Center Exercise and Sports Medicine

Resource Center Joint Disorders

Resource Center Trauma

Specialty Site Orthopaedics

NextEpidemiologyFrequencyUnited States

As a percentage of lower-extremity injuries, hamstring injuries peak at 33% in persons aged 16-25 years, and they most often occur in sports in which the hamstrings can be stretched eccentrically at high speed.[5, 6, 7, 8, 9, 10] Prime examples of such sporting activities include sprinting, track and field, and other running contact sports, such as football and soccer. Recreational sports such as waterskiing, in which the knee is fully extended during injury, are also common causes of hamstring injuries.[4] One study analyzed data from the National Football League’s Injury Surveillance System and found that a high percentage of hamstring injuries occur in the preseason. Over the 10-year study period, 1716 hamstring strains were noted, with slightly more than 50% occurring during the preseason. Players on the special teams units as well as wide receivers and defensive secondary were found to have an elevated risk for injury.[11]

International

An Australian study involving 1614 individuals with hamstring injuries revealed that such injuries compose 54% of the injuries in rugby, 10% of the injuries in soccer, 14% of the injuries in track, and less than 2% of the injuries in tennis, squash, ballet, and gymnastics.

PreviousNextFunctional Anatomy

The hamstrings are composed of 3 muscles, as follows:

Biceps femoris muscle (long head and short head)Semimembranosus muscleSemitendinosus muscleOrigins and insertions

All of the muscles of the hamstrings originate on the ischial tuberosity. The second head of the biceps femoris (ie, short head) originates medial to the linea aspera on the distal posterior femur.

The short head of the biceps femoris crosses only one joint to insert with the long head of the biceps femoris onto the fibular head and lateral tibial condyle.

The other hamstring muscles cross 2 joints to reach their insertions. The semitendinosus muscle forms the pes anserinus with the sartorius and gracilis tendons to insert on the medial tibial metaphysis. The semimembranosus muscle interweaves with the fibers of the semitendinosus to eventually insert onto the posteromedial tibial condyle.

Innervations

The short head of the biceps femoris muscle is also unique in that it is innervated by the peroneal portion of the sciatic nerve, whereas the long head of the biceps femoris, semimembranosus, and semitendinosus are innervated by the tibial portion of the sciatic nerve.

PreviousNextSport-Specific Biomechanics

In track and field events in which the hamstring is eccentrically contracted, the risk of a hamstring injury can be high. Contact sports such as football can result in contusions of the hamstring muscle.[12, 13] The contusion is superficial when the muscle is contracted on impact, and it is deep when the muscle is relaxed on impact. Waterskiing accidents have an association with proximal, bony avulsions because the individual's knee is extended when the hip undergoes a violent, forceful flexion as he/she falls forward.

Related Medscape topics:

Resource Center Exercise and Sports Medicine

Resource Center Trauma

Specialty Site Orthopaedics

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