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accurate diagnosis and administer the most appropriate treatment so that a more timely return to competition can be achieved.3,6,10,14–16,20,26,28,30,31,35–37,41,43,50,52,56,59,68,71,73

Soccer Injuries

Steven Arsht, Giles R. Scuderi, and Peter D. McCann Soccer is the most popular sport in the world and is the fastest growing team sport in the United States. Because soccer is a contact sport, players are at risk for a number of types of injuries. The average incidence of injury is 10 to 15 per 1000 playing hours. The incidence and severity of injury appears to increase with advancing age, level of play, and frequency of competition. Injuries in young players, however, especially those under the age of 12, are uncommon, and typically do not result in significant lost playing time. Most injuries are caused by direct trauma related to physical contact between players, and up to a third are associated with foul play. Overuse injuries account for 9% to 34% of injuries. Injuries in soccer players most commonly involve the lower extremity, and predominantly affect the ankle and knee, and the muscles of the thigh and calf. Players are more likely to sustain an injury during a game rather than in practice. Center forwards and midfielders have the highest injury rates and goalkeepers are the most likely to sustain upper extremity injuries. Contusions, ligament sprains, and muscle strains account for about 75% of all injuries. Serious, permanently disabling injuries are rare and account for less than 0.1% of injuries at all levels. Female soccer players seem to be more likely than males to be injured in the younger age groups. This difference disappears after puberty, with the exception that knee injuries are about twice as common in women players than in men of the same age and playing level. At all levels of competition, the number and severity of knee injuries, including career-threatening ACL rupture, is greater in female athletes. Knee injuries usually result in the most time lost from participation and are the most common cause for surgery in the soccer player. A thorough understanding of the types of injuries sustained by the soccer player is necessary so that the medical staff can provide a rapid and

HEAD AND NECK A unique aspect of soccer is the purposeful use of the head for advancing and controlling the ball. Because heading the ball is an integral part of soccer, injuries may occur when competing for the airborne ball. Injuries to the head, face, and neck account for between 4% and 22% of all soccer injuries. Most of these injuries are abrasions, minor lacerations, and contusions. More serious injuries such as skull fractures, concussions, epidural hematoma, and cervical spine trauma have been reported. With increasing exposure to the game, the risk and incidence of head injury increases. Accidental blows to the head may occur during the course of competition. Concussions account for roughly 2% to 3% of all soccer injuries, but are probably more common than previously reported. These injuries typically result from a collision with other players, the ground, or the goalpost, and not from intentional heading of the ball. Dental injuries are uncommon, and their occurrence can be diminished by the use of protective mouthguards. Eye injuries such as hyphema, retinal edema, vitreous and retinal hemorrhage, corneal abrasion, traumatic iritis, and retinal tears have all been reported. Prompt ophthalmologic consultation should be strongly considered in players with persistent pain, diplopia, or decreased vision. A comprehensive physical examination of the head and neck is mandatory. If cervical spine injury is suspected, immediate immobilization is required. Depending on the severity of the injury and level of comfort of the treating physician, additional medical expertise can be received through consultation with an ophthalmologist, neurosurgeon, dentist, oral surgeon, otolaryngologist, or plastic surgeon. Significant neurotrauma is rare but should be aggressively evaluated if suspected. If a player has experienced a loss of consciousness, immediate transport to the hospital for a comprehensive neurologic examination, including advanced imaging studies such as a CT scan or MRI, is recommended. Concerns have been raised about the cumulative effects of heading and its relation to brain injury in soccer players. Although some authors attributed neuropsychologic deficits in soccer players to the cumulative effects of heading the ball, other investigators have failed to show any correlation between career heading exposure and the development of a chronic encephalopathy. It is likely that long-term encephalopathic changes result from a combination of acute and chronic injuries, rather than heading the soccer ball.7,8,12,22,25,33,45,46,68,69,70,73

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BACK, TRUNK, AND PELVIS Injuries to the back, trunk, and pelvis are uncommon in soccer and account for less than 10% of all injuries resulting in lost playing time. Complaints of lower back pain are often the result of muscle strains or ligament sprains and typically respond well to conservative treatment. Spondylolysis may be seen in goalkeepers because of the repetitive lumbar hyperextension required in diving saves. Degenerative disc disease and disc herniation are rare. Persistent or recurrent back pain or radicular symptoms should alert the physician that additional diagnostic evaluation is necessary. X-rays, along with advanced imaging studies such as MRI and SPECT scan, are useful.20,68,73 CHRONIC GROIN PAIN Soccer places repetitive stresses on the hip, inner thigh, and lower abdominal musculature, making both acute and chronic injuries in these areas quite common. Recurrent adductor, abdominal, and iliopsoas strains, tendinitis, osteitis pubis, and osteoarthritis are all frequent sources of groin pain in the athlete. Inguinal and femoral hernias and genitourinary and visceral pathology should also be considered in the clinician’s differential diagnosis. Consultation with a general surgeon is often helpful when evaluating an athlete with groin pain. Athletic pubalgia refers to a chronic inguinal or pubica area pain in athletes, which is noted on exertion. The pain appears to be related to weakness in the pelvic floor musculature between the inguinal canal and rectus abdominus insertion. The condition may begin insidiously, however, many athletes describe a hyperextension injury in association with hyperabduction of the thigh, followed by groin pain that is progressive, exacerbated by exertion such as running, and lasting several hours or days afterward. The pain is primarily felt in the inguinal region but can radiate posteriorly to the ischium or superiorly to the lower abdomen. The symptoms are clearly aggravated by activity and relieved by rest. Sit-ups can be painful. In the majority of athletes, the pain causes them to stop competing in sports. On physical exam, pain can be reproduced with active hip flexion, adduction, and internal rotation against resistance. A small percentage of patients will have point tenderness in the inguinal region near the anterior pelvic tubercle or along the adductor tendons near the pubis. The acute management of groin pain is conservative and includes rest, ice, compression, NSAIDs, and massage. If the pain continues for several months and prevents the athlete from competing, then surgical treatment may be considered.14,20,28,30,49,68,71 UPPER EXTREMITY INJURIES Upper extremity injuries account for 5% to 15% of all soccer injuries, and rarely result in lost playing time. These injuries are more common in goalkeepers and

typically occur as a result of contact with the ball. Injuries to the hand are usually caused by player collision, ground contact, foul play in field players, and by direct or indirect trauma in goalkeepers. Indirect noncontact injuries occur when a player falls on the outstretched hand or onto the point of the shoulder. Finger fractures, dislocations, and mallet fingers can occur from ball impacts on the ends of fingers. Forearm fractures, wrist fractures, or sprains may also occur as the goalkeeper attempts to stop oncoming shots. Fractures of the scaphoid or injury to the scapholunate ligament can occur when forced dorsiflexion of the hand and wrist is encountered when the player falls on the outstretched hand or when the goalkeeper attempts to block a shot. If a bony or ligamentous injury is suspected, radiographic and magnetic resonance imaging evaluation is necessary. Acromioclavicular joint separations should be suspected in field players with shoulder pain who give a history of falling onto the point of the shoulder.11,14,20,43,50,68 LOWER EXTREMITY INJURIES Injuries in soccer players most commonly involve the lower extremity, and predominantly affect the ankle and knee and the muscles of the thigh and calf. Overuse injuries such as stress fractures and tendinitis of the leg, ankle, and foot are frequently encountered. The occurrence of foul play puts players at increased risk of serious injury and is directly responsible for approximately 22% to 33% of all soccer injuries.3,6,10,16,20,28,30,41,56,68,71 Contusions Contusions to the thigh and calf are common but rarely result in lost playing time. Contusions of the thigh represent one of the most common contact injuries in soccer, especially in young players. Partial ruptures of the quadriceps muscle can occur as a result of impact against the contracted muscle, such as can occur when one player’s knee hits an opposing player’s thigh. Another cause of quadriceps muscle strains or partial rupture is noncontact overload, such as occurs during sudden explosive contractions in a fast start or sprint. Deep muscle contusions can be disabling and lead to complications such as acute compartment syndrome or myositis ossificans. Myositis ossificans can develop after a deep muscle contusion, particularly in the anterior thigh. Examination reveals a tender, erythematous, firm mass. X-rays demonstrate a fluffy opacity with increased peripheral density. Treatment of deep thigh contusion is conservative, with rest, ice, and anti-inflammatory medication. Massage should be avoided. Passive range of motion and whirlpool therapy can help maintain mobility and should be initiated as early as possible. The use of shin guards reduces the frequency of leg contusions and season-ending tibia fractures, and are now required in many leagues.20,30,68

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Muscle Strains Strains of the hamstrings, adductors, and quadriceps are common in soccer players and can result in extended periods of lost playing time. Frequently overlooked as minor injuries, these strains can become chronic, recurrent injuries that have a great effect on the player’s ability to compete. The treatment is conservative, with rest, ice, compression, and elevation in the first 24 hours to help minimize bleeding and edema. Anti-inflammatory medication can also be helpful. Gentle passive range of motion should be started as soon after the injury as possible, followed by active motion, stretching, and strengthening as soon as tolerated. Soccer players with increased tightness of the hamstring or quadriceps muscles are at increased risk for injury. Players at risk can be identified through formal flexibility testing. Preseason hamstring and quadriceps muscle conditioning, proper warm-up, and pregame stretching can limit the frequency and severity of muscle strains and injuries.3,6,10,14,16,20,28,30,41,56,68,71 Knee Injuries Knee injuries are the most common reason for surgeries in soccer players and can result in significant physical disability and lost playing time. Meniscal tears and ligament injuries in soccer typically result from pivoting or sudden deceleration stresses rather than from direct contact. Articular cartilage or osteochondral injuries are not uncommon and may result from hyperextension loading of the strong shot or kick. Such lesions typically occur in the femoral condyle and should be suspected when a persistent effusion develops in the absence of discrete point tenderness or instability. Isolated posterior cruciate ligament rupture can occur if a player is struck directly against the proximal anterior tibia. Tears of the ACL are generally the most disabling of knee injuries for the soccer player and account for the majority of time lost due to knee injuries. The rate of ACL injuries in women is much higher than in their male counterparts. The majority of cases are traumatic noncontact injuries. These injuries are often a result of overuse, fatigue, physical overload, or inadequate training. Reduced muscle strength may predispose players to noncontact injuries of the knee, especially in youth and lower-skill players. Conditioning and strength training may play an important role in reducing the incidence of knee injuries. A history of prior injury and instability of the knee may predispose soccer players to subsequent major knee injury. The severity of knee injuries increases with age. Contact with opposing players and foul play, such as tackling and kicking, represent additional factors predisposing players to ACL injury. Few soccer players are able to remain competitive with an ACL-deficient knee despite strengthening and bracing. Surgical reconstruction should be recommended for all patients who wish to continue playing competitive soccer. The diagnosis and

management of knee injuries is discussed in detail elsewhere in this book.3,4,6,14,20,23,30,41,50,56,61,62,63,68 Overuse Syndromes of the Knee Iliotibial band friction syndrome, popliteus tendinitis, patellar tendinitis, pes anserine bursitis, and irritation of synovial plicae are common overuse syndromes of the knee seen in soccer players. Subluxing biceps femoris tendons have been reported as a cause of lateral knee pain in soccer players. Iliotibial band syndrome is caused by excessive friction between the iliotibial band and lateral femoral condyle. Players report lateral knee pain that progressively worsens with running after a pain-free start. There is tenderness over the ITB at the lateral femoral condyle. Symptoms may be reproduced with a single-leg squat. Excessive iliotibial band tightness can be determined by the Ober test. Treatment is conservative and consists of relative rest, ice, NSAIDs, ITB stretching, ultrasound, and other local modalities. An occasional bursal injection of corticosteroid may be helpful in chronic cases. In refractory cases, surgical treatment may be necessary. Patellar tendinitis develops from cyclic overloading of the extensor mechanism during jumping and kicking. The player will complain of anterior knee pain inferior to the patella that is most pronounced when competing, running, and kicking. Symptoms will often resolve with a period of rest. On examination, there is tenderness over the inferior pole of the patella. Exacerbation of symptoms can be seen with resisted knee extension. The patellar tendon may feel thickened or swollen. Hamstring tightness and hip flexor weakness may also be seen. Conservative treatment is generally sufficient and should focus on quadriceps, hamstring, and hip flexor strengthening. Relative rest and modalities including ice, ultrasound, and iontophoresis or phonophoresis can be helpful. A short course of nonsteroidal anti-inflammatory medication can be prescribed. Steroid injections should never be given. X-rays should be obtained in the initial evaluation of players with patellar tendinitis. MRI is recommended for evaluation of chronic symptoms and can be helpful in differentiating patellar tendinitis from a partial tear. Chronic tendinitis with pathologic changes within the tendon evident on MRI may respond to surgical treatment.1,24,51,55,57,74 Tibia Fractures A direct kick to the anterior leg is common in soccer and may result in a tibia fracture. Shin guards are helpful in decreasing the incidence of tibia fractures and are effective at decreasing soft-tissue trauma. A fracture should be strongly suspected if an injured player is unable to bear weight and complains of shin pain. Prompt radiographic evaluation is mandatory. Nondisplaced fractures can be treated with a functional fracture brace and progressive

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weight bearing. Displaced or comminuted fractures may require intramedullary nailing. Return to play can be expected after several months. Stress fractures of the tibia can also occur and result in a significant loss of playing time. This condition should be considered in the differential diagnosis when evaluating an athlete with leg pain. The diagnosis and management of tibial stress fractures are discussed elsewhere in this book.5,17 Chronic Exertional Compartment Syndrome Chronic exertional compartment syndrome presents as activity-related leg pain. The anterior compartment is most commonly affected, although the lateral and deep posterior compartments can also be involved. The differential diagnosis includes tibial stress fracture, venous thrombosis, and medial tibial stress syndrome or shin splints. Typically, the athlete will complain of pain during and immediately after exercise, particularly running. The pain is described as aching or cramping, increases with the intensity of exercise, and improves with rest. Symptoms resolve quickly after stopping exercise and are not present during normal activities of daily living. Players may not be able to play through the pain and often will take themselves out of the game. On physical exam, tenderness may be localized to the involved compartment or may be absent, especially if considerable time has lapsed since the exercise session. Examination performed immediately after exercise may reveal a tense, tender area localized near the involved compartment. Fascial herniations may also be noted. Radiographic evaluation is useful in ruling out conditions such as stress fractures, tumors, or periostitis. Pre- and postexercise intracompartmental pressure measurements are diagnostic. Treatment is surgical release of the involved muscle compartment.1 Ankle Sprains Ankle sprains are the most common injuries accounting for lost playing time at all age levels and levels of competition in soccer. The lateral ankle ligaments are the most frequently injured structures and account for the vast majority of injuries sustained by soccer players today. Deltoid and syndesmotic injuries are less common. Sudden and uncontrolled inversion and plantarflexion of the foot and ankle or “rolling” of the ankle that occurs when a player steps awkwardly can result in injury to the lateral supporting structures. Injury is often accompanied by anterolateral ankle pain and swelling. The athlete may have difficulty bearing weight. There is tenderness over the lateral aspect of the ankle. A thorough examination is required to rule out bony and tendinous injuries. Fractures of the fibula, fifth metatarsal, acute traumatic peroneal tendon dislocation or rupture, and osteochondral

injuries can occur and should be considered in the differential diagnosis. X-rays should be obtained to confirm the presence or absence of associated pathology. Stress views may be helpful once the acute period of injury has subsided to objectively document ankle stability. The treatment is conservative and a rehabilitation program should be started as soon as possible to work on proprioception and general strengthening and conditioning of the musculature of the foot and ankle. A soccer player’s ball control depends heavily on ankle and foot coordination. This rehabilitation is critical in reducing the incidence of symptomatic instability, pain, and recurrent ankle sprains in the future. Inadequate treatment and rehabilitation of ankle sprains increases a player’s predisposition to reinjury. It is not unusual for a player to experience persistent pain and swelling for many months after a severe ankle sprain. Players with a history of repeated ankle sprains and residual joint laxity may benefit from taping or bracing. Chronic lateral ankle pain in the athlete who has previously sustained an ankle sprain could be a result of incomplete rehabilitation, lateral talar exostosis, interosseus ligament tears, unrecognized syndesmosis sprain, subtalar instability, meniscoid lesion, anterior tibiotalar impingement, or lateral gutter synovial impingement and evaluation should proceed accordingly. Arthroscopy can be useful in the diagnosis and treatment of these disorders. Players with chronic recurrent ankle sprains and functional instability may be candidates for surgical reconstruction.9,13,14,16,18–21,29,38,40–42,47,53,58,64,68 Athletes with a syndesmotic injury or “high ankle sprain” take longer to return to full activity than those with a typical anterolateral ankle sprain. Athletes describe the foot moving in external rotation and dorsiflexion at the time of injury. Most players immediately recognize that this injury is different from a common ankle sprain. On physical exam, there is less swelling than that seen with a lateral ligament injury. Ecchymosis may be present proximal to the ankle joint. There is tenderness along the lateral aspect of the distal tibia and a positive squeeze test and external rotation stress test. Widening of the syndesmosis on x-ray is diagnostic. Mild sprains can be treated conservatively with ice, elevation, compression, and crutches to minimize weight-bearing activity. Early mobilization is permitted and return to play is possible when the player is comfortable. Return to play can take up to six weeks. Moderate sprains are immobilized and weight bearing is restricted for several weeks. Athletes can be expected to return to sport within 8 to 10 weeks. Severe sprains with syndesmotic diastasis require surgical treatment. Return to sport may take 5 to 6 months. Chronic pain after syndesmotic injury may indicate subtle instability, heterotopic ossification, or soft-tissue impingement.47

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Peroneal Tendon Subluxation or Dislocation Acute peroneal tendon dislocations are rare injuries that are frequently misdiagnosed as lateral ankle sprains. Subluxation or dislocation of the peroneal tendons can be a cause of chronic lateral ankle pain. The injury occurs with forceful ankle dorsiflexion and inversion, causing the superior peroneal retinaculum to tear and the preoneus brevis to dislocate anteriorly. A split-tear in the tendon may occur at the time of injury. Traumatic rupture of both peroneal tendons has been described in soccer players. Symptoms include swelling and tenderness in the lateral retromalleolar region over the peroneal tendons. Having the player actively evert the foot or roll the foot in circles may allow for the tendons to be observed subluxing. Maximal tenderness and swelling are along the posterior aspect of the distal fibula, and the player will be unable or reluctant to dorsiflex and evert against resistance. A “rim” fracture from the lateral ridge of the distal fibula may occasionally be seen on radiographs indicating avulsion of the superior peroneal retinaculum. MRI is useful to evaluate the retinaculum and to assess the integrity of the tendons. Conservative treatment includes the use of a non–weight bearing short leg cast for four weeks. Symptomatic chronic peroneal tendon subluxation is an indication for surgical reconstruction.9,47

Achilles Tendonopathy and Rupture Players with Achilles tendinitis complain of pain over the posterior ankle that is worse with running and jumping. Examination may reveal tenderness over the tendon in the watershed area 4 to 6 cm above the os calcis, with increased warmth, swelling, and crepitus. Tenderness at the posterior heel may indicate insertional tendinitis or retrocalcaneal bursitis. An antalgic gait, painful single toe rise, and variable gastrocnimeus-soleus weakness can also be seen. Chronic symptoms may be indicative of tendon degeneration. Acute, complete ruptures are less common but can occur and are usually associated with a pop, extreme pain and swelling, a palpable defect, and a positive Thompson test. X-rays should be obtained in all cases. MRI can be helpful in defining the extent of the athlete’s injury. Relative rest, ice, stretching, NSAIDs, ultrasound, heel lifts, and orthotics are the mainstay of treatment. A period of immobilization may be helpful in difficult cases. Players with MRI evidence of Achilles tendinosis that has failed an adequate course of immobilization may require exploration of the degenerative tendon. Athletes with chronic partial tears do poorly with conservative treatment and most are unable to return to their preinjury level of competition. Surgical treatment is often successful. It is recommended that elite athletes with Achilles tendon rupture undergo acute surgical reconstruction.2,18

Ankle Impingement Syndromes Anterior Ankle Impingement Syndrome. Impingement syndromes of the foot and ankle are extremely common in soccer players but remain a diagnostic and therapeutic challenge to the clinician. The formation of tibiotalar osteophytes at the anterior part of ankle joint is a common cause of chronic anterior ankle pain in soccer players. In 1950, McMurray48 named the condition “footballer’s ankle,” a condition that is now commonly referred to as anterior ankle impingement syndrome. It has been suggested that this is an overuse type of injury, and that spur formation is related to recurrent ball impact and chronic repetitive microtrauma to the anteromedial aspect of the ankle. Players will complain of anterior ankle pain, particularly with jumping. Diagnosis is confirmed with the findings of limited active and passive dorsiflexion, pain with forced dorsiflexion, and radiographic evidence of spur formation, which is best seen on the lateral ankle x-ray. The initial treatment is conservative. Heel lifts, NSAIDs, and avoidance of excessive dorsiflexion can be helpful. If symptoms persist and the player cannot compete, then surgical excision may be beneficial.14,44,48,54,65,68 Anterolateral Soft-Tissue Impingement. Anterolateral soft-tissue impingement of the ankle is commonly seen as a result of repetitive ankle injury. A hyalinized connective tissue lesion can form in the anterolateral gutter and result in pain and the feeling of instability. A high success rate has been reported with arthroscopic treatment.40 Posterior Impingement Syndrome. Posterior impingement syndrome, also called os trigonum syndrome, involves impaction of the os trigonum and/or the posterior capsular structures between the tibia and calcaneus. Players complain of a vague posterior ankle pain that is worsened by kicking or passive ankle dorsiflexion. Retrocalcaneal tenderness is evident on exam. X-rays are typically negative, but may show a fracture of the posterior talar process. MRI is useful in defining additional pathology, such as a flexor hallucis longus tendinitis. The differential diagnosis of a soccer player with posterior ankle pain should include Achilles tendinitis, retrocalcaneal bursitis, flexor hallucis longus tendinitis, and stress fracture. Chronic posterior impingement of the talocalcaneal joint during instep kicking may result in failure of the synchondrosis to ossify or lead to stress fracture of the posterior talar process. Symptomatic os trigona are treated conservatively. Persistent symptoms may warrant surgical excision.72 Peroneal Tendinitis Attritional tears of the peroneus longus and brevis tendons can occur in the soccer player. More commonly, however, the athlete will experience an acute tendinitis

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or traumatic subluxation of the tendons. Peroneal tendinitis presents with diffuse lateral retromalleolar pain. Differentiation between tendinitis, partial longitudinal tearing of the peroneus brevis, lateral gutter synovial impingement, and peroneal tendon subluxation must be made. A history of subjective ankle instability, weakness, popping, and swelling may be elicited. Players may have an antalgic gait, tenderness in the lateral retromalleolar groove, swelling, crepitus, and pain with passive inversion of the subtalar joint. X-rays are typically negative. MRI is helpful in defining the extent of tendon injury and facilitating surgical planning. The mainstay of treatment of peroneal tendinitis is rest, ice, NSAIDs, and physical therapy. A lateral heel wedge and stirrup brace may also be used. A period of immobilization is helpful in cases that are slow to respond. Recalcitrant cases with MRI evidence of tearing of the peroneal tendons may benefit from surgical exploration and repair. Occult ankle instability may be associated with these injuries and should be assessed.18 Flexor Hallucis Longus Tendinitis Flexor hallucis longus (FHL) tendinitis presents as a medial retromalleolar ankle pain, and develops as a result of repetitive hyperplantarflexion of the ankle during kicking. It can be seen alone or in combination with posterior ankle impingement. On examination, with the ankle dorsiflexed, there is limited dorsiflexion of the great toe and pain. With subsequent plantarflexion of the ankle, there is increased dorsiflexion of the great toe with less discomfort. A local injection of 1% lidocaine that eliminates pain with forced plantarflexion confirms the diagnosis. The physician must differentiate flexor hallucis longus tendinitis from posterior tibial tendinitis, Achilles tendinitis, and retrocalcaneal bursitis. Early treatment of FHL tendinitis is conservative, with NSAIDs, rest, and early restrictive taping of the ankle and first MTP joint. A brief period of immobilization may be required. In refractory cases, surgical debridement may be necessary.18 FOOT INJURIES Midfoot Sprains Sprains of the midfoot can occur as isolated injuries but are usually associated with tarsal or tarsometatarsal fractures. A common mechanism of injury in soccer players occurs when a plantarflexed foot is planted on the ground and is struck from behind by another player. Swelling of the midfoot and inability to bear weight is highly suggestive of a tarsometatarsal joint injury. On examination, there is marked pain with palpation of the midfoot, particularly over the second MTP joint, in conjunction with provocative side-to-side midfoot compression and dorsi-plantar stress of the first and second metatarsal

joints. Weight-bearing radiographs are helpful in assessing tarsal alignment. Excessive pain may prohibit weight-bearing x-ray, in which case a bone scan or CT scan helpful diagnostic studies. Diastasis of the first or second tarsometatarsal joints more than 2 mm requires surgical treatment. In the absence of diastasis, conservative treatment is appropriate and consists of immobilization and restricted weight bearing for 4 to 6 weeks. Medial midfoot sprains take much longer to heal than lateral sprains and return to competition can take up to several months.27,47 Plantar Fasciitis The most common cause of hindfoot pain in sports is plantar fasciitis. Repetitive microtrauma during bursts of sprinting can lead to significant damage to the plantar fascia in soccer players and cause arch or heel pain. It is characterized by the insidious onset of medial plantar heel pain that is worse when getting out of bed in the morning or after sitting for a period of time. Physical exam shows point tenderness at the medial origin of the plantar fascia or distally along the medial longitudinal arch. Heel or plantar arch pain can be reproduced by passively dorsiflexing the toes of the foot. Achilles tendon contracture may be present. X-rays are often negative but may show calcaneal traction spur. Nonsurgical treatment is successful in nearly all cases. A regimen of Achilles tendon and plantar fascia stretching combined with activity modification, NSAIDs, heel cushions or arch supports, a dorsiflexion night splint, and corticosteroid injection may be successful in the majority of players. Recalcitrant cases may benefit from immobilization for several weeks. If symptoms persist beyond 6 to 9 months of appropriate conservative treatment, then surgical release may be indicated.18 Fifth Metatarsal Fractures Fractures of the proximal third of the fifth metatarsal are common in sports that involve significant amounts of running and jumping. Players may present with the insidious onset of a vague, dull ache along the lateral border of the foot that is exacerbated during play and relieved with rest, or with the acute onset of pain along the fifth metatarsal. X-rays may demonstrate an obvious fracture with sclerosis indicating the chronicity of the problem. Typically, a history of prodromal symptoms combined with intramedullary sclerosis and a widened fracture line is indicative of a preexisting stress fracture. Conservative treatment with casting and strict non– weight bearing has been successful; however, there is an increased risk of delayed union, nonunion, and hindfoot stiffness with this treatment. Primary surgical management with intramedullary screw fixation is the treatment of choice in competitive athletes and serves as a more

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reliable and predictable treatment option that allows for a more timely return to competition. Forced inversion of the foot and ankle during competition can result in acute, traumatic fractures of the diaphysis of the fifth metatarsal. Fractures involving the base of the metatarsal can be confused with an ankle sprain, and moderate tenderness along the lateral border of the foot should alert the medical staff that x-ray evaluation is necessary. Conservative treatment is generally sufficient and players may return to competition in six weeks or when comfortable enough to do so.27,34,66 Digital Fractures Contusions to the toes are so common in soccer players that many fractures tend to go unnoticed. Fractures are typically caused by direct trauma from ball strike or contact with another player. Discrete tenderness, swelling, and crepitus discovered while examining the toes should alert the physician to fracture. X-rays are taken to confirm the diagnosis. Phalangeal fractures rarely require surgical intervention, with the great toe being the rare exception. Some phalangeal fractures can be loosely buddy taped to adjacent toes for comfort or simply left alone in a shoe with a wide toe box or stiff sole. Early weight bearing can improve outcome and healing times. Athletes should return to play when comfortable enough to appropriately compete.27 Stress Fractures Stress fractures of the foot and ankle in soccer are most typically seen in elite or professional players with heavy daily training and game schedules. Stress fractures in the forefoot usually involve the second and third metatarsal shafts. Stress fractures of the fourth and fifth metatarsals are less common. Physical exam may demonstrate swelling, tenderness, and pain on passive motion of the involved toe. X-rays may show periosteal reaction in diaphyseal stress fracture but can be negative. Bone scan or MRI can be diagnostic. Conservative treatment with relative rest and avoidance of pain-producing activity is generally successful. Immobilization is rarely necessary. Custom-molded rigid pedal orthosis may be used by the player, who may return to play when comfortable. Refractory cases or those involving the proximal fifth metatarsal may require surgical treatment.18,27 Navicular Stress Fractures Navicular stress fractures present with the insidious onset of forefoot pain that is worse with activity. Players frequently complain of diffuse ankle and midfoot pain during running and kicking. The symptoms are vague and physical findings often are nonspecific. A delay in diagnosis is not uncommon and players are often

misdiagnosed with a forefoot sprain and treated inappropriately for an extended period of time before an accurate diagnosis is obtained. If the diagnosis is suspected and plain radiographs are equivocal, MRI or CT scan can be ordered to confirm the diagnosis. The treatment for early, incomplete, nondisplaced fractures requires the athlete to be immobilized in a short leg cast and prohibited from bearing weight for six weeks, followed by gradual resumption of activity over the next six weeks. A CT scan can be repeated to confirm healing. If progressive healing is evident, return to play may be expected within 12 to 18 weeks from the time treatment was initiated. If there is displacement, delayed union, or nonunion, then surgical treatment will be necessary.18,27,39,67 Calcaneal Stress Fractures Calcaneal stress fractures are infrequent but remain part of the differential diagnosis of heel pain in soccer players. Players may complain of vague symptoms and are often misdiagnosed as having plantar fasciitis, os trigonum, retrocalcaneal bursitis, or Achilles tendinosis. A dense sclerotic line may be seen on x-ray. Bone scan or CT scan will confirm the diagnosis. Stress fractures of the os calcis require at least six weeks of rest. The athlete is instructed to participate in activities, staying below the level of pain. A walking boot can be used and removed to work on range of motion so hindfoot stiffness can be minimized.18,27 Malleolar Stress Fractures Stress fractures involving the medial and lateral malleoli should be considered in soccer players complaining of persistent ankle pain, especially in the setting of recurrent ankle sprains. Distal fibula stress fractures can be confused with ankle sprains or peroneal tenosynovitis. Exquisite point tenderness over the distal fibula or anteromedial tibia is highly suggestive of a stress fracture. X-rays are often negative and MRI or bone scan can be diagnostic. Medial malleoli stress fractures are potentially unstable and are at risk of nonunion. If the fracture is not displaced, then treatment consisting of immobilization and non–weight bearing may suffice; however, if the fracture should displace or be slow to heal, then surgical treatment is recommended. Lateral malleoli stress fractures are more stable and generally heal with conservative treatment.18,27 Sesamoiditis and Sesamoid Fractures Injury to the hallucal sesamoids is common among soccer players. Repetitive microtrauma during loading cycles at the great toe during soccer may lead to stress fractures or avascular necrosis. The presence of a metal stud or cleat directly beneath the first MTP joint on nearly all soccer

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shoes aggravates this problem by increasing local stresses, particularly during the push-off phase of running. Over time, this may lead to increased local ischemia and avascular necrosis with fragmentation of the sesamoid. Stress fractures involving the medial sesamoid are most common and the risk of nonunion is high. There is localized tenderness over the sesamoid that is exacerbated by passive dorsiflexion of the great toe. A local lidocaine injection that results in complete symptomatic relief is diagnostic. Axial radiographs are useful and a bone scan or MRI can provide additional diagnostic support. Treatment is symptomatic, with ice, NSAIDs, and a custom-molded foot othosis. Immobilization is helpful in cases slow to respond. Surgical excision may be considered in recalcitrant cases.18,32,60 Turf Toe Injury to the plantar capsule of the first MTP joint is commonly referred to as “turf toe.” Partial tearing of the plantar capsule of the hallucal MTP joint occurs with repetitive forced hyperdorsiflexion, which may occur during the push-off phase of running in a player wearing a soft and flexible shoe. In chronic cases, the condition is aggravated by push-off and cutting. The severity of the injury may vary, however, and more acute injuries are extremely painful and the player is often too uncomfortable to continue in the game. On examination, there is exquisite tenderness over the plantar aspect of the first MTP joint and the pain is made worse with passive dorsiflexion. Moderate swelling may also be seen. Conservative treatment is generally sufficient, and taping of the toe to prevent excessive dorsiflexion is helpful. A thin steel prefabricated insole or a custom orthosis can also be used. A high incidence of chronic problems are associated with turf toe, such as hallux valgus, hallux rigidis, and chronic pain, reflecting the potential severity and disability resulting from this injury.18 Reverse Turf Toe (Soccer Toe) Acute and chronic capsular damage to the dorsal aspect of the hallucal MTP joint can be seen in soccer players. This typically results from repetitive forced hyperplantarflexion of the joint, especially during instep ball strike, because of the supple nature of the toe box. Significant functional disability can result from the injury, which can compromise push-off, forward drive, running, and jumping. Diagnosis is confirmed by physical exam. There is swelling and tenderness over the hallucal MTP joint and the pain is exacerbated by passive plantarflexion of the joint. Soccer toe responds well to conservative management, which consists of taping, anti-inflammatory medication, ice, and rest, along with a toe strengthening program. Taping to prevent MTP plantarflexion is helpful. A prolonged recovery can be seen and players may be

unable to compete for some time, particularly if the great toe of the dominant foot is involved. Some athletes may experience chronic pain, loss of dorsiflexion, and hallux rigidis.18 Hallux Rigidis Hallux rigidis is a progressive degenerative disorder of the first metatarsalphalangeal joint associated with localized pain, limited motion, and prominent dorsal osteophytes. Post-traumatic arthritis of the hallucal MTP joint can occur as a result of previous fracture, osteochondritis, avascular necrosis, turf toe, or soccer toe. Athletes complain of pain and stiffness in the great toe, which is particularly noticeable while cutting or pushing off. A chronically stiff and tender first MTP joint is found on examination. The pain is exacerbated by forced dorsiflexion of the first MTP joint. X-rays demonstrate dorsal osteophytes and first MTP joint space narrowing. The initial treatment is conservative and consists of rest, NSAIDs, and a custom orthosis or carbon footplate insert. Intraarticular corticosteroid injections may be helpful, but the results are often unpredictable. A cheilectomy or arthrodesis may be necessary in recalcitrant cases. A first MTP joint arthrodesis is recommended for advanced disease in soccer players because of the need for strong push-off during running.18 Subungual Hematoma Most soccer players will sustain numerus subungual hematomas during their careers. These injuries generally involve the great toe as a result of a direct crush by the foot of another player or from the shear stresses of sudden stops and starts as the toe impacts the toe box. For many players, the toenail becomes dystrophic due to the repeated damage to the nail bed. An acute subungual hematoma can be quite painful and the initial treatment should involve releasing the pressure of the blood collected beneath the nail. The nail should be left intact even if it is detached from the nail bed.18 CONCLUSION Most injuries are caused by direct trauma related to physical contact between players. The occurrence of foul play puts players at increased risk for serious injury and is directly responsible for approximately one-third of all soccer injuries. The incidence and severity of injury appears to increase with advancing age, level of play, and frequency of competition. Injuries in soccer players most commonly involve the lower extremity, and predominantly affect the ankle and knee and the muscles of the thigh and calf. Players are more likely to sustain an injury during a game rather than in practice. Contusions, ligament sprains, and muscle strains account for about 75%

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of all injuries. Serious, permanently disabling injuries are rare and account for less than 0.1% of injuries at all levels. At all levels of competition, the number and severity of knee injuries, including career-threatening ACL rupture, is greater in female athletes. Knee injuries usually result in the most time lost from participation and are the most common cause for surgery in the soccer player. Mild head injuries, including lacerations of the scalp, dental, ophthalmologic, and closed head trauma, also represent a significant cause of morbidity. Concussions account for roughly 2% to 3% of all soccer injuries, but are probably more common than previously reported. These injuries typically result from a collision with other players, the ground, or the goalpost, and not from intentional heading of the ball. The development of injury prevention programs and continuing education by the coaching staff in techniques and skills may reduce the incidence of injuries in soccer players over time. Appropriate sport-specific preseason conditioning is helpful in minimizing injuries during the season. It is well known that soccer players with increased tightness of the hamstring or quadriceps muscles are at increased risk for injury. Preseason muscle flexibility testing can identify players at risk so that amendments to the players’ conditioning program can be made and the potential risk of in-season injury reduced. Other factors such as a pregame warm-up with emphasis on stretching, particularly of the adductors, quadriceps, and hamstring muscle groups; a regular cool-down period after training; adequate rehabilitation of specific injuries with sufficient recovery time, including proprioceptive training; the use of protective equipment, such as mouthguards and shin guards; good playing field conditions; and adherence to existing rules and avoidance of foul play, are helpful in minimizing serious injury that could keep the athlete from competition.10,15,28,37,71 REFERENCES 1. Amendola A, Clatworthy M, Magnes S: Overuse injuries of the lower extremity. In Arendt E (ed): OKU Sports Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 365–372. 2. Angermann P, Hovgaard D: Chronic Achilles tendonopathy in athletic individuals: Results of nonsurgical treatment. Foot Ankle Int 20:304–306, 1999. 3. Arendt E, Dick R: Knee injury patterns among men and women in collegiate basketball and soccer. Am J Sports Med 23:694–701, 1995. 4. Bach B, Minihane K: Subluxating biceps femoris tendon: An unusual cause of lateral knee pain in a soccer athlete: A case report. Am J Sports Med 29:93–95, 2001.

5. Bir C, Cassatta S, Janda D: An analysis and comparison of soccer shin guards. Clin J Sports Med 5:95–99, 1995. 6. Bjordal J, Arnoy F, Hannestad B, et al: Epidemiology of anterior cruciate ligament injuries in soccer. Am J Sports Med 25:341–345, 1997. 7. Boden B, Kirkendall D, Garrett W Jr: Concussion incidence in elite college soccer players. Am J Sports Med 26:238–241, 1998. 8. Bruzzone E, Cocito L, Pisani R: Intracranial delayed epidural hematoma in a soccer player: A case report. Am J Sports Med 28:901–903, 2000. 9. Cees C, Verheyen M, Bras J, et al: Rupture of both peroneal tendons in a professional athlete: A case report. Am J Sports Med 28:897–900, 2000. 10. Chomiak J, Junge A, Peterson L, et al: Severe injuries in football players: Influencing factors. Am J Sports Med 28(Suppl 5):S38–S58, 2000. 11. Curtin J, Kay N: Hand injuries due to soccer. Hand 8:93–95, 1976. 12. Daily S, Barsan W: Head injuries in soccer. A case for protective headgear. Physician Sports Med 20:79–85, 1992. 13. Dixon D, Monroe M, Gabel S, et al: Excrescent lesion: A diagnosis of lateral talar exostosis in chronically symptomatic sprained ankles. Foot Ankle Int 20:331–336, 1999. 14. Dvorak J, Junge A: Football injuries and physical symptoms: A review of the literature. Am J Sports Med 28(Suppl):S1–S14, 2000. 15. Dvorak J, Junge A, Chomiak J, et al: Risk factor analysis for injuries in football players: Possibilities for a prevention program. Am J Sports Med 28:S69–S79, 2000. 16. Ekstrand J, Tropp H: The incidence of ankle sprains in soccer. Foot Ankle 11:41–44, 1990. 17. Francisco A, Nightingale R, Guilak F, et al: Comparison of soccer shin guards in preventing tibia fracture. Am J Sports Med 28:227–233, 2000. 18. Frey C, Feder K: Foot and ankle injuries in sports. In Arendt E (ed): OKU Sports Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 379–394. 19. Frey C, Feder K, DiGiovanni C: Arthroscopic evaluation of the subtalar joint: Does sinus tarsi syndrome exist? Foot Ankle Int 20:185–191, 1999. 20. Fried T, Lloyd G: An overview of common soccer injuries: Management and prevention. Sports Med 14:269–275, 1992. 21. Gerber J, Williams G, Scoville C, et al. Persistent disability associated with ankle sprains: A prospective evaluation of an athletic population. Foot Ankle Int 19:653-660, 1998. 22. Green G, Jordan S: Are brain injuries a significant problem in soccer? Clin Sports Med 17:795–809, 1998.

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23. Griffin L, Agel J, Albohm M, et al: Noncontact anterior cruciate ligament injuries: Risk factors and prevention strategies. J Am Acad Orthop Surg 8:141–150, 2000. 24. Griffiths G, Selesnick F: Operative treatment and arthroscopic findings in chronic patellar tendonitis. Arthroscopy 14:836–839, 1998. 25. Guskiewicz K, Marshall S, Broglio S, et al: No evidence of impaired neurocognitive performance in collegiate soccer players. Am J Sports Med 30:157–162, 2002. 26. Hawkins R, Fuller C: An examination of the frequency and severity of injuries and incidents at three levels of professional football. Br J Sports Med 32:326–332, 1998. 27. Heckman J: Fractures and dislocations of the foot. In Rockwood C, Green D, Bucholz R, Heckman J (ed): Fractures in Adults, 4th ed. Philadelphia, Lippincott-Raven, 1996, pp 2267–2405. 28. Heidt R, Sweeterman L, Carlonas R, et al: Avoidance of soccer injuries with preseason conditioning. Am J Sports Med 28:659–662, 2000. 29. Hertel J, Denegar C, Monroe M, et al: Talocrural and subtalar joint instability after lateral ankle sprain. Med Sci Sports Exerc 31:1501–1508, 1999. 30. Inklaar H: Soccer injuries I: Incidence and severity. Sports Med 18:55–73, 1994. 31. Inklaar H: Soccer injuries II: Aetiology and prevention. Sports Med 18:81–93, 1994. 32. Jahss M: The sesamoids of the hallux. Clin Orthop 157:88–96, 1981. 33. Jordan S, Green G, Galanty S, et al: Acute and chronic brain injury in United States national team soccer players. Am J Sports Med 24:205–210, 1996. 34. Josefsson P: Closed treatment of Jones fractures: Good results in 40 cases after 11–26 years. Acta Orthop Scand 65:545–547, 1994. 35. Junge A, Chomiak J, Dvorak J: Incidence of football injuries in youth players: Comparison of players from two European regions. Am J Sports Med 28(Suppl 5):S47, 2000. 36. Junge A, Dvorak J: Influence of definition and data collection on the incidence of injuries in football. Am J Sports Med 28(Suppl):S40–S46, 2000. 37. Junge A, Rosch D, Peterson L, et al: Prevention of soccer injuries: A prospective intervention study in youth amateur players. Am J Sports Med 30:652–659, 2002. 38. Karlsson J Sward L, Andreasson G: The effect of taping on ankle stability: Practical implications. Sports Med 16:210–215, 1993. 39. Khan K: Outcome of conservative and surgical management of navicular stress fractures in athletes. Am J Sports Med 20:657–665, 1992.

40. Lahm A, Erggelet C, Reichelt A: Ankle joint arthroscopy for meniscoid lesions in athletes. Arthroscopy 14:572–575, 1998. 41. Larson E, Jensen P, Jensen P: Long-term outcome of knee and ankle injuries in elite football. Scand J Med Sci Sports 9:285–289, 1999. 42. Liu S, Baker C: Comparison of lateral ankle ligamentous reconstruction procedures. Am J Sports Med 22:313–317, 1994. 43. Luthje P, Nurmi I, Kataja M, et al: Epidemiology and traumatology of injuries in soccer: A prospective study in Finland. Scand J Med Sci Sports 6:180–185, 1996. 44. Massada J: Ankle overuse injuries in soccer players: Morphological adaptation of the talus in the anterior impingement. J Sports Med Phys Fitness 31: 447–451, 1991. 45. Matser J, Kessels A, Jordan B, et al: Chronic traumatic brain injury in professional soccer players. Neurology 51:791–796, 1998. 46. Matser J, Kessels A, Lezak M, et al: Neuropsychological impairment in amateur soccer players. JAMA 282:971–973, 1999. 47. Mazur D, Bartolozzi A: Ankle soft-tissue injuries. In Arendt E (ed): OKU Sports Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 373–378. 48. McMurray T: Footballer’s ankle. J Bone Joint Surg 32B:68–69, 1950. 49. Meyers W, Ricciardi R, Busconi B, et al: Groin pain in the athlete. In Arendt E (ed): OKU Sports Medicine. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 281–290. 50. Morgan B, Oberlander M: An examination of injuries in major league soccer: The inaugural season. Am J Sports Med 29:426–430, 2001. 51. Nichols C: Patellar tendon injuries. Clin Sports Med 11:807–813, 1992. 52. Nielsen A, Yde J: Epidemiology and traumatology of injuries in soccer. Am J Sports Med 17:803–807, 1989. 53. Noakes T, et al: A fivefold reduction in the incidence of recurrent ankle sprains in soccer players using the Sport-Stirrup orthosis. Am J Sports Med 22:601–606, 1994. 54. Ogilvie-Harris D, Mahomed N, Demaziere A: Anterior impingement of the ankle treated by arthroscopic removal of bony spurs. J Bone Joint Surg 75B:437–440, 1993. 55. Orava S, Malinen L, Karpakka J, et al: Results of surgical treatment of unresolved OsgoodSchlatter lesion. Ann Chir Gynaecol 89(4):298–302, 2000. 56. Peterson L, Junge A, Chomiak J, et al: Incidence of football injuries and complaints in different age groups and skill-level groups. Am J Sports Med 28(Suppl 5):51–61, 2000.

CHAPTER 39

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57. Popp J, Yu J, Kaeding C: Recalcitrant patellar tendonitis: Magnetic resonance imaging, histologic evaluation, and surgical treatment. Am J Sports Med 25:218–222, 1997. 58. Povacz P, Unger S, Miller W, et al: A randomized prospective study of operative and nonoperative treatment of injuries of the fibular collateral ligaments of the ankle. J Bone Joint Surg Am 80:345–351, 1998. 59. Powell J, Barber-Foss K: Sex-related injury patterns among selected high school sports. Am J Sports Med 28:385–391, 2000. 60. Richardsom E: Injuries to the hallucal sesamoids in the athlete. Foot Ankle 7:229–244, 1987. 61. Roos H, Ornell M, Gardsell P, et al: Soccer after anterior cruciate ligament injury: An incompatible combination? A national survey of incidence and risk factors and a 7-year follow-up of 310 players. Acta Orthop Scand 66:107–112, 1995. 62. Rozzi S, Lephart S, Gear W, et al: Knee joint laxity and neuromuscular characteristics of male and female soccer and basketball players. Am J Sports Med 27:312–319, 1999. 63. Shelbourne K, Gray T: Anterior cruciate ligament reconstruction with autogenous patellar tendon graft followed by accelerated rehabilitation: A 2–9 year follow-up. Am J Sports Med 25:786–795, 1997. 64. Thacker S, Stroup D, Branche C, et al: The prevention of ankle sprains in sports: A systematic review of the literature. Am J Sports Med 27:753–760, 1999.

65. Tol J, Slim E, van Soest A, et al: The relationship of the kicking action in soccer and anterior ankle impingement syndrome: A biomechanical analysis. Am J Sports Med 30:45–50, 2002. 66. Torg J: Fractures of the base of the fifth metatarsal distal to the tuberosity: classification and guidelines for non-surgical and surgical management. J Bone Joint Surg Am 66:209–214, 1984. 67. Torg J: Stress fractures of the tarsal navicular. J Bone Joint Surg 64:700–712, 1982. 68. Tucker A: Common soccer injuries: Diagnosis, treatment, and rehabilitation. Sports Med 23:21-32, 1997. 69. Tysvaer A: Head and neck injuries in soccer. Impact of minor trauma. Sports Med 14:200–213, 1992. 70. Tysvaer A, Locher E: Soccer injuries to the brain: A neuropsychologic study of former soccer players. Am J Sports Med 19:56–60, 1991. 71. Witvrouw E, Danneels L, Asselman P, et al: Muscle flexibility as a risk factor for developing muscle injuries in male professional soccer players: A prospective study. Am J Sports Med 31:41–46, 2003. 72. Wredemark T, Carlstedt C, Bauer H, et al: Os trigonum syndrome: A clinical entity in ballet dancers. Foot Ankle 11:404–406, 1991. 73. Yde J, Nielsen A: Sports injuries in adolescents’ ball games: Soccer, handball, and basketball. Br J Sports Med 24:51–54, 1990. 74. Yu J, Popp J, Kaeding C, et al: Correlation of MR imaging and pathologic findings in athletes undergoing surgery for chronic patellar tendonitis. Am J Roentgenol 165:115–118, 1995.

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