Overview of running injuries of the lower extremity

INTRODUCTION — Running is one of the most popular forms of exercise, with approximately 30 to 40 million Americans participating regularly [1-3]. Benefits include improved cardiopulmonary function, reduced risk of obesity and osteoporosis, and enhanced mental health. (See "Overview of the risks and benefits of exercise" and see "Exercise and fitness in the prevention of cardiovascular disease").

Running is not without risk; approximately 35 to 45 percent of participants suffer a running-related injury every year [4]. Since the forces associated with running are largely absorbed by the lower extremity, the majority of injuries occur in the foot and leg. These include intra- and periarticular hip and knee injuries, stress fractures of the tibia, fibula and foot, tendonitis, heel pain, and plantar fasciitis. An overview of lower extremity injuries due to running is presented here.

GENERAL ISSUES — Most running injuries have an insidious onset and are not associated with specific trauma.

Risk factors — Some people beginning a conditioning program are at higher risk of injury. Army recruits represent one group that has been studied to identify potential risk factors. Poor physical fitness, extremes of flexibility (high or low), a prior sedentary lifestyle, and tobacco use are among the factors that increase the risk of exercise related injuries [5]. Malalignment problems such as genu varum, patellar deviations, tibial torsions, and foot pronation may result in overuse injuries.

Among female recreational runners, increasing age may be a risk factors for a new injury. This was illustrated in a study of 844 runners training for a 10 km race [6]. Age greater than 50 years in women was a risk factor and age less than 31 was protective against new injury.

Prior injuries and incomplete rehabilitation may also increase the risk of injury. In the study previously cited [6], one-half of the participants who reported a new injury had previously been injured; 42 percent of these runners reported that they were not completely rehabilitated on starting the 13 week training program. An injury rate of 29.5 percent was recorded across all training clinics surveyed. The knee was the most common site of injury. Every injured runner seeking medical attention should be closely questioned about injury history.

Prevention — Several interventions for prevention of initial or recurrent running related injuries have been evaluated.

Stretching — Traditionally, poor flexibility has been associated with an increased risk of injury. Improved passive and active range of motion can be expected from both passive and active muscle stretching [7]. However, controlled trials have not proven that stretching decreases injury rates. As examples: A trial that randomly assigned 421 runners to an educational intervention regarding warm-up, cool-down, and stretching before and after running did not result in any important difference in the rates of running related injuries between the control and intervention groups (4.9 and 5.5 injuries per 1000 hours of running, respectively) [8]. Another controlled study of the effect of stretching on injury among 901 military recruits revealed no difference in rates of injury; however, the incidence of muscle/tendon injuries and low back pain were significantly lower in the stretching group [9].

A year 2004 meta-analysis by the US Centers for Disease Control and Prevention concluded that there was no statistically significant decrease in risk of total injuries among those who stretched before exercising (OR 0.93, 95% CI 0.78-1.11) [10]. As a result it was concluded that there is insufficient evidence to either encourage or discourage the practice of routine stretching before or after exercise to prevent injury among competitive or recreational athletes.

Distance — Running injuries of the lower extremity are primarily due to training errors and the accumulation of excessive mileage [11]. Reducing the weekly running distance and decreasing the amount of hard surface running may therefore be reasonable suggestions in patients with recurrent running-related injuries. Among 580 habitual runners, running 64.0 km (40 miles) or more per week was the most important predictor of injury for men (odds ratio = 2.9) [12]. Risk also was associated with having had a previous injury in the past year (odds ratio = 2.7), and with having been a runner for less than three years (odds ratio = 2.2).

Footwear — Proper shoe fit and recognition of excessive shoe wear are also important factors in preventing injury. Since the foot often widens with age, shoe size should be reexamined at each time of purchase. Width should be determined while standing. Women, in particular, should be sure that the heel provides adequate support since women's heels typically are much narrower than those of men. The microcellular foam insoles and cushioning may appear normal but can be worn out. New shoes lose approximately 40 percent of their cushioning after running between 250 and 500 miles [13]. The American Podiatric Medical Association recommends running shoes be changed every 350 to 500 miles [14].

Orthoses — Orthoses can be helpful for runners with excessive pronation, leg length discrepancy, patellofemoral disorders, plantar fasciitis, Achilles tendinitis, and shin splints. In one study, most runners preferred a flexible orthosis [15]; however, some practitioners suggest a semiflexible orthosis [16]. For many runners, over the counter orthoses are adequate. Other runners require orthoses which are fabricated from a mold of the patient's feet; podiatrists or orthopedists then send the mold to an orthotist who fabricates the orthotic insert. (See "Rehabilitation program for the lower limb").

Soft insoles — Stress fractures of the tibia may occur in approximately 30 percent of some high-risk groups, such as military recruits undergoing basic training [17]. Systematic reviews of the usefulness of "shock absorbing" soft insoles concluded that the use of this type of orthotic device reduced the risk of stress fracture in "at-risk" individuals (eg, military recruits) [18,19]. Conflicting data exist on the benefit of insoles in running shoes (in contrast to military boots); these are generally designed with built-in shock-absorbing insoles [20].

Ankle braces — Prevention of ankle sprains through the use of ankle braces may also be recommended, particularly for those with histories of prior ankle injuries. A systematic review included 14 randomized trials of external ankle support for mostly active and young individuals [21]. Primary and secondary prevention with semi-rigid braces, air-filled removable casts, and high top shoes were evaluated. A substantial reduction in risk of ankle sprain was seen in those using external support (relative risk 0.53, 95 percent confidence interval 0.40 to 0.69). In addition, the use of pneumatic braces in the rehabilitation of tibial stress fractures significantly reduces the time to recommencing training (weighted mean difference -42.6 days, 95 percent confidence interval -55.8 to -29.4 days) [18].

Evaluation — The general evaluation of the injured runner, independent of a specific evaluation of the site of injury, should include: Information related to training patterns Running experience Weekly mileage Inspection of shoe wear Musculoskeletal examination with an evaluation of the runner's gait and joint alignment, muscle strength, balance and flexibility, and palpation of the soft tissues

Prompt diagnosis in sports medicine is increasingly relying upon magnetic resonance imaging (MRI) for differentiating many lower limb injuries. Where available, MRI may be used to assess runners with injuries of the navicular and tibia for stress fractures and shin splints (see "Shin splints syndrome" below) [22,23]; MRI may also be valuable for unexplained hip and groin pain [24].

Training — A sports therapist can work with the injured athlete to maintain cardiorespiratory endurance during rehabilitation, helping to find an activity that is aerobic in nature, that can be performed at least three times per week for no less than 20 minutes and with a heart rate that is elevated to at least 60 percent of the maximum predicted rate. As healing allows, training can progress to interval, continuous, and full speed play [25].

Treatment — Absolute rest from running, or at least a reduction in pace and running mileage, is the basis of an effective treatment plan for most running-related injuries. Runners can frequently maintain cardiovascular fitness through alternate non-impact activities, like bicycling or swimming. Identifying biomechanical stresses and correcting them is also essential. Although experimental data suggests that active warm-up may be protective against muscle strain injury, the results of clinical research are equivocal [26].

As previously mentioned, a review of proper footwear selection and the use of orthotics for some conditions can be helpful. The use of non-prescription strength doses of nonsteroidal antiinflammatory drugs and acetaminophen may alleviate acute pain. Surgery may be beneficial in selected cases.

FOOT INJURY — Mechanical factors, such as overpronation due to pes planus deformity and microtrauma due to overuse (which may cause stress fractures), are the most important elements associated with foot and ankle injury due to running. The exact site of the pain may help establish the diagnosis (show figure 1A-1C).

Forefoot — Pain in the forefoot may be caused by a stress fracture, arthritis, bursitis, or a neuroma. Stress fracture pain is often felt as a sharp, localized discomfort over a bony surface. Pain over the first metatarsal joint may be due to an underlying osteoarthritis or bursitis involving the first metatarsal phalangeal joint. Hyperextension injury (turf toe) and hallux valgus are other causes of pain at the base of the great toe.

Morton's neuroma is associated with pain and dysesthesia usually felt in the interspace between the third and fourth toes [27] (show figure 2). The diagnosis can be confirmed by noting a clicking sensation (Mulder's sign) when palpating this interspace while simultaneously squeezing all the metatarsal joints. An Intermetatarsal bursitis can cause a similar pain. (See "Nerve entrapment syndromes of the leg and foot" and see "Bursitis: An overview of clinical manifestations, diagnosis, and management").

Midfoot and hindfoot — Although the midfoot is a less common site for pain due to running, pain in this region may be due to stress fracture or plantar fasciitis, which results from an abnormally structured medial arch. These anomalies cause excess mechanical stress (overpronation) to the plantar fascia and its site of insertion into the os calcis.

Overall, plantar fasciitis is one of the most common causes of foot pain in adults. Heel spurs frequently coexist with this condition, representing a secondary response to inflammation [28]. A detailed discussion of the clinical characteristics, diagnosis, and treatment of plantar fasciitis is presented separately. (See "Plantar fasciitis and other causes of heel and sole pain").

ANKLE INJURY — Ankle pain due to running may be the result of sprains, tendonitis, or bursitis involving adjacent structures (show figure 3 and show figure 4).

Sprains — Ankle sprains result from the stretching or tearing of ankle ligaments following inversion or eversion injuries. The ligamentous structures of the medial side of the ankle are much less commonly affected than those of the lateral side, since inversion injury is more common than eversion.

Pain is increased upon ankle inversion with all lateral ankle sprains; the examiner can palpate for tenderness and often determine which portion of the ligament is involved. In contrast, the pain of a medial (deltoid) ligament sprain is accentuated by gentle eversion of the ankle. (See "Ankle sprain" for a detailed discussion concerning the clinical characteristics and treatment of ankle sprains).

Tendonitis — Tendonitis of the ankle area is common since eleven muscles have tendons which cross the ankle. Inflammation and degeneration of a tendon sheath may result from repetitive activity or unaccustomed extraordinary work. In addition, improper footwear often causes injury to the extensor hallucis longus or Achilles tendon.

Tenosynovitis involving the tibialis anterior, tibialis posterior, extensor digitorum longus, or peroneal tendons can occur where the tendons become angulated at the ankle; friction can then cause inflammation of the tendon sheath. A bulbous swelling may occur distally to areas of constriction and is helpful in demonstrating points of constriction.

The posterior tibial tendon is typically involved in a patient with a pronated flat foot. The presenting complaints include an aching mild to moderate pain over the medial ankle and longitudinal arch with weightbearing. Several weeks of persistent pain often have occurred before the patient decides to seek help.

With tendinitis, physical examination frequently reveals tubular swelling of the tendon sheath, tenderness, pain on passive stretching of the tendon and active ankle movement, and normal palpation of the ankle joint. Comparison of findings with the uninvolved side is helpful. (See "Posterior ankle tendinopathies", for a review of the clinical manifestations and treatment of ankle tendinitis).

Achilles tendonitis — Achilles tendonitis is the most common form of tendonitis observed in runners. It can be severe and has been reported to force up to 16 percent of runners to stop running indefinitely [29]. Training errors, such as inappropriate increases in mileage, pace, or hill running, may cause tendon microtears and secondary inflammation.

Affected patients present with pain over the heel. Dorsiflexion of the ankle increases the pain, and a tendon friction rub may be palpable. Pain is noted on palpation of the tendon; there may be soft tissue swelling, redness, and warmth which may involve the adjacent retrocalcaneal bursa.

Treatment options include a rehabilitation regimen, use of topical nitrate ointment. Local injection of glucocorticoids near the tendon may be considered in some cases. Longitudinal tendonotomy may be beneficial for those with refractory tendinitis.(See "Posterior ankle tendinopathies", for a detailed discussion concerning Achilles tendonitis).

The presentation and/or treatment of retrocalcaneal bursitis is similar to Achilles tendinitis; however, those with bursitis may also improve with the addition of a firm "heel cup", which is an orthotic device added to stiffen a shoe's heel counter. (See "Bursitis: An overview of clinical manifestations, diagnosis, and management").

Achilles tendon rupture — Rupture of the Achilles tendon may occur after abrupt calf muscle contraction. This typically occurs in men over the age of 40 who engage sporadically in sports and do not perform a regular leg conditioning program. The patient may note an audible snap, followed by pain in the calf as if struck with a baseball.

On physical examination, the patient may be unable to stand up on the toes. A positive Thompson test (show figure 5) is further evidence of rupture. This test is performed with the patient kneeling on a chair or lying prone on an examination table and the feet hanging over the edge. When the examiner squeezes the calf muscle on the normal side, the foot responds with plantar flexion; on the affected side, there is no foot response.

Urgent orthopedic consultation for immobilization or repair is necessary for patients with tendon rupture. Surgical end-to-end repair performed soon after the injury allows patients to return to their preinjury level of activity in over 90 percent of cases [30]. Percutaneous repair has become an increasingly popular alternative to open repair [31,32]. The success of delayed surgery is less clear; use of allografts and Marlex mesh are under investigation in these cases [33,34]. Extensive postoperative exercise rehabilitation is needed [3].

DISTAL TIBIA-FIBULA INJURY — The causes of pain in the distal tibia-fibula region include the shin splints syndrome (eg, medial tibial stress syndrome), stress fractures, and the exertional compartment syndrome.

Shin splints syndrome — Shin splints syndrome or medial tibial stress syndrome is applied to a complex of pain and discomfort in the lower leg occurring after repetitive overuse. Tibial stress reactions result from a progressive process of injury; it begins with periosteal edema, which leads to marrow involvement, and may culminate in a cortical stress fracture.

Symptoms — Discomfort may emanate from a number of areas (show figure 6 and show figure 1C). These include [35,36]: Lower half of the posteromedial border of the tibia Anterior tibial compartment (containing the tibialis anterior and extensor hallucis longus muscles) Tibia Interosseous membrane region of the foreleg

Patients typically complain of a dull ache followed by a gradually worsening pain. The symptoms are at first relieved by rest, but later become continuous. Accompanying numbness, or loss of sensation over the fourth toe may be noted. The pain usually is confined to the posteromedial portion of the leg, although the site of involvement may be more diffuse; it is much less localized than the pain of stress fractures.

Physical examination — Tenderness can usually be elicited over symptomatic sites during physical examination. Mild swelling and induration may also be evident at the site of tenderness. Sensory or motor nerve deficits suggest a compartment syndrome rather than shin splints (see "Exertional compartment syndrome" below) [36].

Diagnosis — The diagnosis of shin splints syndrome is predominantly clinical and is based upon the history and physical examination. The main diagnostic dilemma often revolves around distinguishing this disorder from a stress fracture. Imaging studies may be necessary in order to make this distinction: Plain films are normal in patients with shin splints syndrome, but may also be normal in those with stress fractures; the latter does not usually produce radiographic changes for two to three weeks, at which time periosteal changes may be seen. Callus formation is typically not apparent until at least four to six weeks after injury (see "Stress fracture" below). Technetium bone scans may show changes within a few days of the injury in patients with either disorder. There often is increased uptake focally in the area of a stress fracture (show bone scan); uptake in patients with shin splints syndrome is less localized and is usually longitudinal involving the posteromedial tibia cortex. Fat-suppressed MRI may be useful in discriminating between stress fracture and shin splints. This was illustrated in a study of twenty-two athletes who had pain in the middle or distal part of their leg during or after sports activity [23]. Result of MRI were compared to those of serial radiographs. Stress fractures were diagnosed when consecutive radiographs showed local periosteal reaction or a fracture line, and shin splints were diagnosed in all the other cases.

In all eight patients with stress fractures, an abnormally wide region of high signal localized to the bone marrow was noted in the coronal fat-suppressed MRI scan. The MRI changes were present prior to periosteal changes on plain radiographs. None of 11 patients with shin splints had this type of bone marrow signal. Instead there were narrower linear high signal areas noted either along the medial posterior surface of the tibia or along the medial bone marrow adjacent to the cortical bone.

Periostitis (often evident on triple phase bone scan or MRI), tears of musculotendinous structures, or ischemic compartment syndromes are additional important diagnostic considerations. Pain out of proportion to the clinical findings is suggestive of a compartment syndrome (see below).

Treatment — RICE is an acronym for the usual care of injuries such as shin splints syndrome that stands for Rest, Ice, Compression of injured tissue, and Elevation. Leg elevation and application of ice packs for 15 minutes at a time are initial treatment measures. Brief rest usually allows the pain to subside, at which time activity may be resumed.

Stretching (lengthening) followed by strengthening exercises directed to the musculature of the involved site of the leg are helpful. (See "Rehabilitation program for the lower limb"). Pelvic, spinal, and lower extremity structure and alignment should be checked for imbalances if the injury is recurrent. (See "Evaluation for subtle structural defects of the lower limb"). Manual techniques such as massage, myofascial release, and pressure applied to trigger/tender points have also been helpful.

The runner should decrease weekly mileage, avoid hard surface running, and shorten the running stride to reduce impact. Changing to shoes with waffle soles and using orthoses with alteration of the heel counter (the hind part of the shoe surrounding the heel) may also be useful in some cases.

Stress fracture — Stress fractures most commonly involve the lower third of the tibia but can also occur in the metatarsals, tarsals, fibula, and sesamoid bones of the foot (show figure 7, show figure 8, show figure 6 and show figure 1C). The etiology is multifactorial, including increased mileage, excessive shoe wear, and running on hard surfaces. In general, stress fractures should be considered an overuse injury to bone. (See "Stress fractures of the tibia and fibula").

In the female runner, components of the "female athlete triad", defined as disordered eating, amenorrhea, and osteoporosis, may be present [37]. A retrospective study of female track-and-field athletes found that those with a history of oligomenorrhea and restrictive eating patterns were six to eight times more likely to suffer a stress fracture [38]. However, measurement of bone turnover is not clinically useful in predicting the likelihood of such fractures [39].

Symptoms — Similar to patients with shin splint syndrome, patients with stress fractures often complain of increasing pain during exercise that subsides with rest. Pain is focal, sharp and exacerbated by weight bearing, and may be referred to sites distant from the fracture. With increasing severity, the pain occurs earlier in the exercise regimen. Some stress fractures, however, may be asymptomatic.

Physical examination — Tenderness and pain is well localized on physical examination. There may be localized swelling without erythema. An intermittent or complete ischemic compartment syndrome should be excluded if pain is out of proportion to the clinical findings.

Diagnosis — Plain radiographs (show radiograph 1) , bone scintigraphy (show bone scan), or magnetic resonance imaging may confirm the diagnosis of stress fracture, although radiographs are often unremarkable in the first two or three weeks following the injury.

Depending on the medical resources available, either triple phase bone scan with technetium or MRI should be considered, but only if pain is severe or longer than 10 days in duration. One study found that MR imaging was more accurate than bone scintigraphy in correlating the degree of bone involvement with clinical symptoms [40]. By comparison, a prospective study evaluating magnetic resonance imaging versus two-phase bone scintigraphy in patients with radiographically negative stress related bone injury found scintigraphy was the superior imaging modality (100 percent sensitivity and specificity) [41].

Treatment — Treatment measures include rest, substitution of sports such as swimming, stretching and strengthening exercises, gentler training, and monitored return to running. (See "Rehabilitation program for the lower limb"). Six weeks of rest is usually sufficient in mild cases. Crutches may be needed if ordinary walking is painful. A fracture shoe is very helpful in cases of metatarsal (March) stress fracture.

As with shin splints syndrome, abnormal biomechanical factors should be recognized and modified. (See "Evaluation for subtle structural defects of the lower limb"). Orthoses are of uncertain value with stress fractures, although there are many anecdotal reports of benefit.

Exertional compartment syndrome — Compartment syndromes are due to increased tissue pressure within a closed muscle compartment that compromises local circulation and neuromuscular function. They require both a constricting envelope (a constricting fascia or cast) and an increase in volume (eg, due to blood, swelling).

Muscle compartments — The leg has four fascial compartments, each enclosed in a constricting fascia (show figure 9) [2]: The anterior tibial compartment contains the tibialis anterior and the extensor hallucis longus muscles. The deep posterior compartment contains the tibialis posterior muscle, the flexor digitorum longus, and the flexor hallucis longus muscles. The lateral compartment contains the fibularis (peroneus) longus and fibularis (peroneus) brevis muscles. The superficial posterior compartment contains the soleus muscle and the two heads of the gastrocnemius muscle.

Compartment syndromes may occur acutely or chronically.

Acute compartment syndrome — An acute syndrome can be induced by limb trauma, drug and alcohol abuse, limb surgery, and limb ischemia. Recognition of this syndrome is important to avoid significant or total loss of neuromuscular function in the affected limb [42].

Increased pain in the anterior compartment following passive flexion of the toes is an early sign of an acute compartment syndrome. Pain, pallor, and pulseless paralysis are late hallmarks of the serious ischemic, posttraumatic syndromes.

Patients with an acute compartmental syndrome may require urgent fasciotomy to alleviate neurovascular symptoms. The outcome is excellent, with more than 90 percent of patients able to return to sports.

Chronic compartment syndrome — A chronic syndrome, resulting from repetitive use, is often confused with other injuries, such as shin splints. Recognition of a chronic compartment syndrome is important since management differs from other lower extremity injuries. Long term neuromuscular sequelae are unlikely in patients with the chronic syndrome unless diabetes or alcohol dependency coexist.

Chronic compartment syndromes may involve the gluteal or quadriceps femoris muscles as well as the lower leg. Exercise normally increases muscle volume and blood flow; further exercise may lead to increased compartment pressure and decreased blood flow.

Patients complain of aching or cramping of the leg in the anatomic distribution of the compartment within 10 to 30 minutes of exercise. There is usually a return to normal function between episodes. Diagnosis — A chronic compartment syndrome may be suspected and differentiated from shin splints when conservative therapy fails to provide relief from recurrent pain with exercise. There may be no diagnostic signs at rest.

Elevated compartment pressure is a confirmatory diagnostic finding for acute or chronic compartment syndromes; pressures are usually >20 mmHg. Pre- and post-exercise compartment pressures can be determined in patients suspected of having a chronic syndrome by using a wick catheter inserted into the suspected compartment [43-45]. Similarly, the central plantar compartment pressure can be determined if a compartment syndrome in the foot is suspected [46,47]. Pre- and post-exercise magnetic resonance imaging using a radiopharmaceutical agent (methoxy isobutyl isonitrile) has also been used to demonstrate and document the location of a chronic compartment syndrome [48]. Treatment — As with the acute syndromes, surgery is also the only effective treatment for chronic compartment syndromes, although the situation in these cases is not urgent [49,50]. Stretching and conditioning exercise should be tried. (See "Rehabilitation program for the lower limb"). One study performed outpatient fasciotomy using local anesthesia in 70 patients with chronic compartment syndromes [49]. Over 90 percent were cured or had significant improvement in symptoms or function at a median follow-up of 4.5 months. The median time to unassisted walking and resumption of conditioned running was 2 and 21 days, respectively.

KNEE PAIN — The knee is the most common site for running injuries. The repetitive stress of running may cause knee pain due to overuse or by activation of a previously dormant knee injury involving the patellofemoral joint, menisci, or soft tissue structures surrounding the knee (show figure 10).

The evaluation of the patient with knee pain commonly involves knee radiographs; these should include weight-bearing anterior and posterior views, a lateral view with the knee in 45 degrees of flexion, and tangential and skyline views of the patella [40]. Magnetic resonance imaging should be considered in the evaluation of persistent knee pain due to a suspected intraarticular process, such as a meniscal injury.

Patellofemoral pain — The patellofemoral pain syndrome has been observed in approximately 25 percent of runners attending a sports medicine clinic [51,52]. It is also referred to as patellofemoral dysfunction or chondromalacia patellae. (See "Evaluation of the adult patient with knee pain").

The pain in this syndrome is attributed to a combination of overtraining and anatomical/biomechanical forces. During the running gait cycle, both ground reaction forces and body impact must be absorbed by the musculoskeletal system. This results in forces equivalent to two to six times body weight being absorbed across the lower extremity [53,54].

Patellofemoral pain is more commonly observed in women because they possess a wider pelvis, thereby increasing femoral anteversion, genu varum, tibial torsion and foot overpronation. Other anatomic variables which enhance the risk for this syndrome include instability of the patella, excessive tightness of the lateral retinaculum, and weakness of the vastus medialis muscle [55].

Symptoms — The pain is described as a diffuse anterior knee discomfort, which is exacerbated by exercise, climbing stairs, or sitting with the knee in a flexed position for an extended period of time. With running, there may be a sense of popping, catching, or the knee giving way.

Physical examination — Physical examination reveals pain with compression of the patella or with forced extension of the knee. The patella may track abnormally within the patellar groove causing crepitation or there may be lateral subluxation (show radiograph 2). The quadriceps and hamstring muscles may atrophy and lose flexibility.

Treatment — Physical therapy is the mainstay of treatment. Patella stabilization braces are often helpful. This is usually a self-limited condition, lasting from months to a few years, with the pain improving slowly as fibrocartilage replaces the degenerating surface of the patella. (See "Evaluation for subtle structural defects of the lower limb" and see "Patellofemoral pain syndrome").

The importance of conservative management was highlighted in a study of 40 young women with patellofemoral pain syndrome [56]. No significant differences were found between the most symptomatic knee and the least symptomatic knee, nor between patients and controls with regard to leg alignment, Q-angle, and leg-heel alignment. Pain was associated with increased activity, suggesting that chronic overloading and temporary overuse of the patellofemoral joint, rather than malalignment, contributed to patellofemoral pain.

Iliotibial band syndrome — The iliotibial band consists of connective tissue that runs from the ilium to the fibula. In patients with this syndrome, an aching or burning pain is felt at the site where the band courses over the lateral femoral condyle and, occasionally, the pain radiates up the thigh toward the hip. There may also be an abnormal shortened iliotibial tract. The tightness of the iliotibial band can be tested for by having the patient lie on the side with the involved side up. The examiner lowers the straight involved leg forward and downward noting any discomfort, tautness, and tenderness, when compared to the uninvolved leg. Risk factors include a varus alignment of the knee, excessive running mileage, worn shoes, or continuous running on uneven terrain [57]. The role of hip abductor weakness which has been noted in runners with this injury is uncertain, but the weakness typically improves with rehabilitation [58].

The treatment of iliotibial band syndrome includes rest, NSAIDs, stretching, physical therapy, and attention to contributing factors, such as shoes, techniques and running surface. Local corticosteroid injection into the areas of tenderness can be helpful, but the patient must refrain from running for at least two weeks following the injection. Anecdotally, some patients have found relief with the use of a pull-on knee sleeve, possible due to a decrease in knee flexion. Rarely, in selected patients, surgical release of the iliotibial band may be beneficial.

PELVIC AND HIP PAIN — Exacerbation of an underlying hip joint disease, such as osteoarthritis, may become apparent, particularly in the older runner or with increases in mileage. Pubic ramus stress fractures may also present with groin pain [59]. Muscle overuse injuries, such as proximal hamstring tendonitis and groin strains, are common in runners. Other lesions, such as acetabular labral tears, hip capsule laxity and instability, chondral lesions, osteonecrosis, ligamentum teres injuries, snapping hip syndrome, iliopsoas bursitis, and loose bodies may be found on MRI or by hip arthroscopy [24].

MUSCLE STRAIN AND TEARS — Injuries to muscle may present in one of four broad clinical categories [60]: Acute Chronic Acute exacerbation of a chronic problem Subclinical alteration of function

Most injuries result in partial disruption of muscle fibers in certain muscle groups; these most commonly include the hamstring, rectus femoris, gastrocnemius, and adductor longus muscles [61]. Symptoms consisting of focal pain and limited flexibility develop acutely or insidiously. A localized hematoma may develop at the site of a sizable muscle tear.



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