Hussein Elkousy MD
Gregory Stocks MD
Hip Pain
Anatomy
Three joints make up the pelvic girdle: the hip joint, the sacroiliac joint, and the pubic symphysis. The pubic symphysis and sacroiliac joint allow little motion. The ball-and-socket configuration of the hip is designed to provide stability and mobility for the body.
Several bony prominences act as muscular origins and insertions in the hip and pelvis (Figure 2-1). The anterior superior iliac spine (ASIS) and greater trochanter are easily palpable in most athletes. The ASIS is the origin of the sartorius. The greater trochanter is the insertion of the gluteus medius. The anterior and posterior iliac crest, symphysis pubis, and ischial tuberosity can be palpated in most individuals. The hip adductors originate from the pubis and the hamstring tendons originate from the ischial tuberosity. The anterior inferior iliac spine (AIIS) is the origin of the direct head of the rectus femoris. The lesser trochanter is not palpable, but it is the site of insertion of the iliopsoas tendon.
Although there may be some overlap in the function of some of the muscles of the hip and pelvis, most have a specialized role. The primary hip flexor is the iliopsoas. The gluteus maximus is the most important hip extensor. The hip abductors are the gluteus medius and minimus. The tensor fascia lata and its extension, the iliotibial band, provide additional stability to the hip during single-leg stance. The hip is adducted by a large group of muscles that originates from the pubis and inserts onto the medial femur. These include the adductor longus, adductor magnus, and adductor brevis.
Several muscles cross the hip and knee joint. Muscles that cross two joints are generally more prone to injury. These are the rectus femoris, the hamstrings, and the iliotibial tract.
Several bursae in the hip and pelvis serve to reduce friction between tendons and surrounding structures. Some of the more important are the greater trochanteric, ischial, and iliopsoas bursae. These are common sites of irritation and pain with overuse.
The acetabular labrum is a cartilaginous structure that lines the periphery of the acetabulum and deepens the hip socket by 30%. However, its primary function is to provide squeeze film lubrication to the cartilage of the femoral head. It creates a vacuum phenomenon that contributes to hip stability. The ligamentum teres, which enters the fovea of the femoral head, is not an important source of blood supply to the femoral head in adults. It may, however, contribute to hip stability, limiting external rotation. The hip capsule is tightened in external rotation and extension.
Differential Diagnosis
Diagnosing the etiology of hip pain can be a daunting task. Pain felt in the hip and pelvis may originate from hip structures or it may be referred from structures in the torso or viscera. As such, the Differential Diagnosis is broad and includes pathology of the abdominal viscera, lumbar spine, or genitalia. Differential diagnoses that should be entertained when diagnosing hip pain include meralgia paresthetica, hernia, athletic pubalgia, and piriformis syndrome. This chapter will address only those pathologies directly related to athletic hip injuries: contusions, avulsions, bursitis, stress fractures, and articular derangements.
Contusions About the Hip & Pelvis
Essentials of Diagnosis
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Figure 2-1. Bony prominences of the hip and pelvis and the muscular origins. (Reproduced, with permission, from Anderson K et al: Am J Sports Med 2001; 29:521. ) |
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Prevention
Contusions about the hip and pelvis are an unavoidable consequence of contact sports. Because of the inherent risks involved in greater contact, certain sports, such as football, hockey, or lacrosse, result in more contusions. It is difficult to prevent these injuries. Of course, some measures may be implemented. In football, hockey, and lacrosse, players wear protective padding over hip and pelvic prominences. In addition, wearing other pads, such as shoulder pads, is less likely to result in a contusion to another player. The surface of play can also be a significant factor in injury. For example, although there are no data to support the assertion that fewer contusions occur on natural grass than on artificial turf, this seems to be a commonly held assumption.
Clinical Findings
Each sport and each specific site of injury differs in precise history, but all injuries share the common theme of direct trauma. The most common sites of injury are the bony prominences, although the soft tissue areas of the thigh can also be involved. The commonly affected bony prominences are the iliac crest, the pubic ramus, the greater trochanter, and the ischial tuberosity. Injuries to the iliac crest are often referred to as “hip pointers” and injuries to the soft tissue of the thigh are referred to as a “charley horse.”
The athlete complains of pain over the specific site that is aggravated by direct contact and, often, exacerbated by use of associated muscle groups. Pain may be localized to the hamstrings with ischial tuberosity injuries or to the quadriceps with anterior thigh contusions. Because most of the lower extremity muscles are involved in walking, many of these injuries result in the athlete walking with a limp.
The most reproducible sign is pain with palpation over the site of injury. This occurs with both superficial and deep injuries. Swelling and ecchymosis may be apparent. Patients may have pain with passive stretch of the involved or overlying muscle. Active resistance may also elicit pain. A contusion of the iliac crest, for example, may result in pain with active abduction or passive adduction of the hip. A contusion of the anterior thigh causes pain with knee extension or hip flexion.
Acutely, plain radiographs are generally obtained to rule out a fracture. Contusions will not yield any radiographic findings. The only other useful imaging technique is magnetic resonance imaging (MRI) (Figure 2-2). This may demonstrate a hematoma or an occult fracture not seen on plain radiographs. Generally, however, this is not useful acutely and may be reserved for patients who fail to improve after initial conservative management.
No special tests exist for diagnosing a contusion. However, compartment syndrome should be considered if swelling is profound. In these cases, compartment pressures should be measured. This applies in particular to the proximal thigh and even to the gluteal region. Elevated pressures that warrant treatment should follow general guidelines for compartment syndrome. These include a pressure above 30 mm Hg or a pressure within 30 mm Hg of the diastolic blood pressure. However, it should be noted that even with elevated compartment pressures, these injuries may be treated with observation with good results.
Complications
Complications with contusions are rare. Compartment syndrome may occasionally occur as mentioned. This may result in some muscle fibrosis with associated loss of range of motion. A second possible complication is the development of myositis ossificans (Figure 2-3). This may be avoided by minimizing the period of immobilization after the injury and minimizing the development of a hematoma. The resulting hematoma
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may eventually form a calcified mass. This mass is best assessed with plain radiographs or a computed tomography (CT) scan. It is differentiated from a soft tissue sarcoma by the history of trauma as well as its radiographic appearance. Myositis ossificans develops in a centripetal fashion resulting in a peripheral rim of calcification that subsequently progresses centrally. If it does not cause significant symptoms, it may be ignored. However, if it is symptomatic, it may be resected after it has matured. Maturation is best assessed by bone scan and may require several months to occur.
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Figure 2-2. Coronal and axial magnetic resonance images of muscle contusion. A: Coronal view of acute hematoma and edema of vastus lateralis. B: Axial view of acute injury. C: Coronal view of injury at 3 weeks with hematoma replaced with fluid collection. D: Coronal view at 3.5 months demonstrating resolving injury. (Reproduced, with permission, from Diaz JA et al: Am J Sports Med 2003;31:289. ) |
Treatment
The goals of treatment are return of painless full range of motion and strength in a timely fashion. Initial management is conservative. This entails controlling pain and swelling. These can be managed initially with ice, nonsteroidal antiinflammatory medications, and relative rest. The relative rest may require the use of crutches if weight bearing or walking is painful. This should be done for the first 24–48 hours. The focus should then
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shift to rehabilitation with restoration of range of motion with passive stretching. This may be started initially by immobilizing the involved muscle group in a lengthened or stretched position. This is most commonly done for a proximal quadriceps contusion by keeping the knee in a flexed position. Concomitantly, with the stretching regimen, the surrounding muscle groups are strengthened. Activity is gradually resumed as full range of motion and full strength are obtained.
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Figure 2-3. Myositis ossificans in a 15-year-old boy secondary to a deep anterior thigh contusion. A: Anteroposterior view of the proximal thigh. B:Lateral view of mid thigh. |
Surgery is generally not indicated for contusions. Occasionally, however, a hematoma may need to be surgically decompressed or a compartment syndrome may require fasciotomies.
Some patients may have extensive swelling or may simply fail to progress with conservative management. These patients may have a large hematoma that prevents them from improving rapidly. In these cases, an MRI may be obtained and the hematoma may be aspirated.
Prognosis
The prognosis is excellent for most contusions about the hip and pelvis. The athlete can generally return to full sport activity without limitations.
Return to Play
The time to return to play is difficult to predict with contusions. It depends on the seriousness of the injury, the site of the injury, and the athlete's response to the injury. It ranges from no time off to several weeks off.
Anderson K et al: Hip and groin injuries in athletes. Am J Sports Med 2001;29(4):521. [PMID: 15297126]
Diaz JA et al: Severe quadriceps muscle contusions in athletes. A report of three cases. Am J Sports Med 2003;31(2):289. [PMID: 12642267]
Avulsions About the Pelvis
Essentials of Diagnosis
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Prevention
No definitive data exist to prove that stretching provides any protective benefit against avulsion injuries. However, preparing the muscle–tendon unit for the large loads required to cause an avulsion injury may afford some benefit.
Clinical Findings
Athletes describe an eccentric load to the injured muscle–tendon unit. Pain is acute and may be associated with a pop in a skeletally immature athlete. The mechanism of injury varies with the specific site of injury. For example, an avulsion of the ischium occurs from knee extension and hip flexion. Activities that classically result in these injuries include water skiing and running the hurdles. An avulsion of the AIIS occurs from eccentric hip extension or resistance against forceful flexion of the hip. This may occur with sprinting or kicking. An avulsion of the ASIS may occur from eccentric hip and knee extension.
The athletes complain of pain at the specific site of injury with direct contact and with use of the avulsed muscle–tendon unit. An ischial avulsion injury causes discomfort with sitting. An ASIS injury results in pain when standing erect. Pubic injuries result in groin pain.
Findings from the physical examination are similar to those for contusions. The history plays a large part in differentiating an avulsion injury from a contusion. All injuries may result in ecchymosis, swelling, and tenderness to palpation over the site of injury. Pain is reproduced with passive stretching or active contraction of the injured muscle–tendon unit.
An ischial avulsion injury is tender over the ischium. Pain is elicited with passive hip flexion and varying degrees of knee extension. Resisted knee flexion with an extended hip also causes pain. An avulsion of the AIIS or rectus femoris results in pain with passive hip extension and knee flexion or active hip flexion and knee extension. An avulsion of the ASIS or sartorius results in pain with simultaneous passive hip and knee extension or active hip and knee flexion. An avulsion of the gluteus medius or the greater trochanter results in pain with passive hip adduction or active hip abduction. An avulsion of the lesser trochanter or iliopsoas tendon results in pain with passive hip extension or active hip flexion.
Plain radiographs are useful in the skeletally immature patient. They are usually normal in adult patients unless the injury is chronic or is a recurrence of a childhood injury. Avulsion injuries in skeletally immature patients generally result in apophyseal fractures. These can be seen on plain films (Figure 2-4A). In descending order, the most common avulsion fractures in the skeletally immature athlete are ischial tuberosity, AIIS, and ASIS avulsions (Figure 2-4B). Iliac crest, greater trochanter, lesser trochanter, and pubic avulsions are less frequently seen. The equivalent injury in an adult results in a soft tissue injury not apparent on a plain radiograph (see Table 2-1).
MRI is more useful for the skeletally mature patient. It may demonstrate the site of a muscle or tendon tear, the extent of the tear, and any associated edema or hematoma (Figure 2-5).
Complications
Complications of conservative management include weakness and the potential for reinjury. Specific injuries such as an ischial apophysis avulsion may result in a calcific mass at the site of injury (Figure 2-6). This mass may irritate the sciatic nerve or it may cause discomfort with sitting. This may necessitate surgical intervention to remove the mass. These masses may also form at other sites of injury and may also require delayed surgical removal. Often, a more sinister etiology, such as a malignant tumor, must be considered; therefore, at least a biopsy, and often complete surgical excision, is warranted.
Treatment
Most avulsion injuries are treated nonoperatively. Conservative management involves relative rest with comfortable positioning and the use of crutches for non-weight-bearing activities to minimize pain. Ice and pain medication may be used initially. A gradual stretching regimen is initiated with pain as a guide to the level of activity. As pain dissipates, weight bearing is allowed and full painless range of motion is restored. Isometric exercises are gradually implemented, followed by isotonic strengthening. Activities are gradually increased until full motion and strength are restored.
Many reports have been published specifically addressing injuries in the skeletally immature patient. The consensus is that most injuries should be treated nonoperatively. However, in injuries with greater than 2 cm of displacement of the apophyseal fragment, in particular, injuries to the ischial apophysis, consideration should be given to surgical fixation. This procedure can generally be done using two screws to fix the avulsed apophysis to the ischium (Figure 2-7).
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Figure 2-4. Apophyseal avulsion injuries. A: Left ischial avulsion in a 14-year-old track athlete. B: Right AIIS avulsion fracture in a 15-year-old male sustained while kicking a soccer ball. |
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Table 2-1. Avulsion injuries in the skeletally immature and skeletally mature individual. |
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Soft tissue injuries in adults should also initially be treated nonoperatively. One notable exception, however, involves injuries to the hamstring origin. These have been shown to benefit from surgical repair. This can be done using suture anchors to fix the torn tendon end to the ischium (Figure 2-8).
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Figure 2-5. Hamstring avulsion. A: Sagittal view showing torn tendon end (arrow) and hematoma (asterisk) it, ischial tuberosity. B: Axial view showing hematoma (asterisk) and tendon void. (Reproduced, with permission, from Bencardino JT et al: Top Magn Reson Imaging 2003;14:145. ) |
Prognosis
The prognosis is good for a full recovery. Generally, ischial or hamstring injuries tend to recover more slowly and have a higher likelihood of recurring than injuries to other sites.
Return to Play
Injuries of the origins at the ASIS or AIIS generally recover in 4–6 weeks. Assuming no complications, the time between injury and return to full sport activity may range from several weeks to several months.
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Figure 2-6. Sagittal CT reconstruction of a calcific mass at the level of ischial tuberosity secondary to an old avulsion fracture. The patient presented with pain when sitting. |
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Figure 2-7. Open reduction and internal fixation of a displaced ischial avulsion fracture in a skeletally immature male. Preoperative radiograph is shown in Figure 2-4A. |
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Figure 2-8. Technique of hamstring avulsion repair. A: Skin incision. B: Suture anchor repair of the tendon to ischial tuberosity. (Reproduced, with permission, from Klingele KE et al: Surgical repair of complete hamstring. Am J Sports Med 2002;30:743. ) |
Klingele KE, Sallay PI: Surgical repair of complete proximal hamstring tendon rupture. Am J Sports Med 2002;30(5):742. [PMID: 12239012]
Moeller JL: Pelvic and hip apophyseal avulsion injuries in young athletes. Curr Sports Med Rep 2003;2(2):110. [PMID: 12831668]
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Trochanteric Bursitis
Essentials of Diagnosis
Prevention
Adequate stretching of the iliotibial band and warm up prior to exercise may help prevent trochanteric bursitis, but no data exist to support this.
Clinical Findings
Patients complain of lateral hip pain that may occasionally radiate along the distal lateral thigh. The pain may begin insidiously, but it may occasionally be acute. When it is acute, it can generally be traced to a specific fall or collision and it may be associated with a contusion. Patients may report a snapping sound or sensation in the hip as well.
Trochanteric bursitis is most common in female runners. Because females, in general, have a broader-based pelvis than their male counterparts, they are more susceptible to friction over the greater trochanter. Some runners may identify a causative factor for their symptoms such as an increase in their mileage or an increase in the level of difficulty of their training course. Additionally, if running is done on the road, often only one leg will be affected. This leg is generally the leg on the outer side of the road, which is affected by the drainage slope incorporated into the design of roads. Other provocative activities include lying on the affected side.
The patient is tender over the greater trochanter with direct palpation. Care should be taken to differentiate this from gluteus medius tendinitis. That pain is more proximal and is directly associated with active abduction. The most provocative positions for trochanteric bursitis are external rotation and adduction. The Ober test may demonstrate tightness of the iliotibial band.
Imaging studies are useful only for differential diagnosis. If the diagnosis is straightforward by physical examination, imaging studies are not necessary. Magnetic
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resonance imaging may demonstrate fluid or inflammation in the bursa, but it is generally not needed to make the diagnosis.
Complications
The main complication of trochanteric bursitis is failure to resolve. This may eventually necessitate surgical management.
Treatment
Generally, trochanteric bursitis is managed nonoperatively. The first line of management includes relative rest from precipating activities, iliotibial band and tensor fascia lata stretching, gluteal muscle strengthening, and antiinflammatories. The second line of treatment may include modalities such as iontophoresis and ultrasound. If these fail or if the patient cannot tolerate the symptoms, a steroid injection into the point of maximal tenderness may be of benefit. A majority of patients will improve with conservative management.
Patients rarely require operative intervention for greater trochanteric bursitis. However, if the pain persists in spite of conservative management, surgery may be performed. Several procedures have been described with most focusing on releasing the iliotibial band with or without debridement of the trochanteric bursa. Reports in the literature indicate good success for these procedures with return to full sport activity over several months.
Most procedures involve a longitudinal incision over the greater trochanter. The iliotibial band, gluteus maximus, and tensor fascia lata are identified. The trochanteric bursa lies between the iliotibial band and the greater trochanter. It may be approached by creating a longitudinal incision in the iliotibial band and excising the bursa. Prior to closure of the wound, the iliotibial band may be Z-lengthened or an ellipse of tissue may be excised.
Prognosis
The prognosis is generally good for return to sport activity and resolution of symptoms with conservative management.
Return to Play
No published studies exist in the literature regarding trochanteric bursitis and return to sports. Generally, several days to several months may be required before the athlete is able to return to full uninhibited activity. The athlete can often continue to participate with some discomfort in spite of the symptoms.
Stress Fractures of the Pelvis & Femur
Essentials of Diagnosis
Prevention
Several factors contribute to the development of stress fractures. These can be divided into intrinsic and extrinsic factors. Extrinsic factors include footwear, running surface, and type or intensity of activity. Intrinsic factors include osteopenia and alignment abnormalities such as coxa vara. Many of these factors need to be addressed to prevent the occurrence or recurrence of stress fractures. For long distance running, using well-cushioned running shoes or running on more forgiving surfaces may minimize the incidence of femoral neck stress fractures. Gradually increasing the intensity of training rather than an abrupt increase can minimize the development of all types of stress fractures.
Intrinsic factors are less readily addressed. Alignment issues may be addressed with orthotics. Osteopenia is more common in women athletes and is associated with female athlete triad. This requires more extensive management using medications and diet.
Clinical Findings
Depending on the location of the stress fracture, patients typically complain of pain in the low back, buttock, groin, thigh, or even the knee. The pain is initially noticed after activity, but it may then progress to pain with activity or pain with weight bearing. Athletes usually seek medical advice when the pain interferes with their regimen of exercise or when it occurs with weight bearing. In general, the athlete will not remember any particular trauma.
The physical examination is limited. Patients will tend to walk with an antalgic gait. For sacral or pubic stress fractures, patients will be tender over the site of the
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fracture. For femoral neck stress fractures, there is no specific site of point tenderness. Range of motion of the hip may be reduced due to pain resulting from femoral neck stress fractures. Internal rotation, in particular, may be limited. Sacral stress fractures may be painful with the Patrick test. Pubic stress fractures may involve pain with pelvic compression.
A metabolic workup to evaluate the female patient for osteopenia may be necessary.
Plain radiographic changes may not appear for up to 4 weeks. Findings include cortical hypertrophy, sclerosis, or lucency. Radiographs for a sacral stress fracture would include, at a minimum, an anteroposterior radiograph of the pelvis, an inlet view of the pelvis, and a lateral view of the lumbosacral spine. Radiographs for a pubic stress fracture would require an anteroposterior view, inlet and outlet views, and Judet views of the pelvis. Radiographs for a femoral neck stress fracture would require an anteroposterior radiograph of the pelvis, an anteroposterior radiograph of the hip, and a frog leg view of the hip.
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Figure 2-9. Bone scan of a left sacral stress fracture (arrow). (Reproduced, with permission, from Johnson AW et al: Am J Sports Med 2001;29:498. ) |
A CT scan of the hip or pelvis is useful for all stress fractures of the hip and pelvis. Coronal and sagittal reconstructions are helpful in identifying a fracture. Findings are the same as those expected on plain radiographs including sclerosis, cortical hypertrophy, and a lucent line. A bone scan is useful in identifying increased activity in stress fractures (Figure 2-9). Bone scans have a high sensitivity but low specificity in detecting stress fractures, with false-positive rates up to 30%. In addition, they may be used as a guide for healing and return to sport activity.
MRI is highly sensitive and specific in diagnosing stress fractures. Stress reactions may be differentiated from stress fractures. Both result in edema that is hypointense on T1-weighted images and have increased signal on fat-suppressed T2-weighted images. However, a stress fracture will have a low signal line within the edematous region that may extend to a cortex.
Complications
Femoral neck stress fractures must be considered early in the differential diagnosis and ruled out prior to considering other possibilities due to the potentially devastating results from a missed diagnosis. If the diagnosis is
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missed, the stress fracture may progress to a complete fracture. This is generally more difficult to correct and may require open reduction with internal fixation. Long-term sequelae include delayed union, nonunion, or avascular necrosis. These conditions may necessitate prosthetic replacement or osteotomy of the hip, which both yield a poor result in this active population.
Treatment
Most hip and pelvic stress fractures are managed conservatively. Depending on the site of the fracture and the level of symptoms, the athlete may initially require crutches for non-weight-bearing activities. As the symptoms subside, weight bearing is permitted. Activities are gradually increased with pain as the guide. Stress reactions are treated the same as stress fractures, but recovery is generally faster.
During the period of convalescence, non-weight-bearing conditioning is permitted. This includes swimming, pool exercises, and riding a stationary bicycle if these activities are not painful.
Management of femoral neck stress fractures is dictated by the type of fracture. Generally, they are divided into tension or compression sided fractures. Compression side fractures occur on the inferior cortical surface. Treatment is conservative because they are less likely to result in a complete fracture. Weight bearing is limited depending on the level of pain. Patients who have pain with weight bearing should be placed on crutches and not permitted to bear weight. This may have to be continued for up to 6 weeks. They are then gradually progressed to weight bearing as tolerated if it is painless. The decision to progress to more strenuous activity is difficult and is based on level of pain. Surgery may be indicated in patients who fail to improve with prolonged nonsurgical management.
Tension-sided fractures have a greater potential to progress to a complete fracture. Radiographically, these are found on the superior cortex of the femoral neck. Fractures that progress to a complete fracture are more likely to displace; therefore, they are treated with surgical fixation. Fixation may generally be done percutaneously for incomplete unicortical fractures or for nondisplaced complete fractures. Fluoroscopy is used to place three cannulated screws through the lateral cortex into the femoral head. These screws may range in diameter from 6.0 to 7.3 mm depending on the size of the patient. Typically the screws are placed in a triangular configuration for maximum stability. After internal fixation, the screws may be removed at 6 months to 1 year. This may avoid a more complicated removal at a later time.
Prognosis
The prognosis is good for return to full sport activity for most hip and pelvic stress fractures. The notable exception is tension side femoral neck stress fractures. These must be treated as described above with a guarded prognosis initially.
Return to Play
It may require up to 6 months to return to full sport activity for some athletes with femoral neck fractures. Repeat radiographs or bone scans may be helpful to determine if the fracture has healed sufficiently to allow a return to sport activity. As the weight-bearing status is advanced, radiographs are obtained to ensure that the fracture does not progress.
Bencardino JT et al: Magnetic resonance imaging of the hip: sports-related injuries. Top Magn Reson Imaging 2003;14(2):145. [PMID: 12777887]
Hip Pain with Mechanical Symptoms
Anatomy
The iliopsoas tendon and the anterior acetabular labrum lie within several millimeters of each other. The iliopsoas tendon lies immediately anterior to the anterior hip capsule and labrum (Figure 2-10).These two structures lie in such close proximity that there is a bursal communication between the hip joint and the iliopsoas tendon sheath in 20% of individuals. The acetabular labrum is continuous with the hyaline articular cartilage of the acetabulum (Figure 2-11). In fact, the bony acetabulum and its tidemark extend into the labrum.
Differential Diagnosis
Hip pain associated with mechanical symptoms or snapping has been classified as external, internal, and intraarticular. External snapping hip pain occurs at the greater trochanter and may be associated with trochanteric bursitis. External snapping hip and trochanteric bursitis are described above and will not be discussed further in this section. Internal and intraarticular causes of a snapping hip are discussed in the following sections.
Causes of groin pain other than the iliopsoas tendon and the acetabular labrum should also be considered. These include inguinal hernia, nerve entrapment, lumbar radiculopathy, osteitis pubis, stress fractures of the pelvis or femoral neck, and hip instability. Idiopathic hip instability has been described as a cause of groin pain associated with snapping. Patients with symptomatic hip instability have an abnormal gait. They walk with the leg abducted and externally rotated. Hip pain that is associated with mechanical symptoms of clicking, popping,
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catching, locking, or giving way is often caused by intraarticular pathology or snapping of the iliopsoas tendon. Intraarticular pathology includes tears of the acetabular labrum, loose bodies, synovial chondromatosis, and arthritis. Another source of intraarticular pathology is a “lateral impaction injury,” which may result from a hard fall directly onto the greater trochanter. The force transmitted from the impact can result in full-thickness loss of the articular cartilage of the femoral head or chondronecrosis of the superomedial acetabulum. MRI will show an altered signal within the femoral head that can mimic osteonecrosis and it may occasionally reveal a chondral defect.
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Figure 2-10. Note the close proximity of the iliopsoas tendon and the anterior acetabular labrum, two structures that can be responsible for hip pain felt in the groin associated with mechanical symptoms. (Reproduced, with permission, from Pelsser V et al: AJR Am J Roentgenol 2001;176:67. ) |
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Figure 2-11. Cross section of a normal acetabular labrum. The articular edge of the labrum blends into the hyaline cartilage of the acetabulum. There is a limited blood supply to the periphery of the labrum. (a) Labrum; (b) articular hyaline cartilage; (c) articular cartilage–labrum transition zone; (d) bony acetabulum; (e) tide-mark; (f) hip capsule (cut); (g) capsular recess; (h) group of vessels. (1) Capsular recess; (2) thickness of labrum; (3) width of labrum. (Reproduced, with permission, from Seldes et al: Clin Orthop Relat Res 2001;382:232. ) |
Symptoms from an internal snapping hip are usually of insidious onset, often following a change in workout routine. Repetitive activities involving high hip flexion can be provocative. Plain radiographs of the hip are usually normal. Groin pain with mechanical symptoms in an athlete caused by a labral tear usually follows an acute injury. Pain that does not follow an acute injury can occur in an athlete with a degenerative labral tear, or with an underlying developmental abnormality of the hip such as dysplasia (Figure 2-12) or femoral–acetabular impingement (Figure 2-13). These abnormalities are often apparent on plain radiographs.
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Figure 2-12. An (A) anteroposterior pelvis and (B) false profile view of a 20-year-old male who forfeited a college baseball scholarship due to right hip pain. There is severe acetabular dysplasia of the right hip. The mild dysplasia of the left hip is asymptomatic. |
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Figure 2-13. A 24-year-old right-footed soccer player with right groin pain due to femoral–acetabular impingement. There are typical radiographic findings of loss of the normal concavity of the superior femoral neck. There are also subchondral cysts (arrows) at the junction of the femoral head with the neck. |
Byrd JW: Lateral impact injury. A source of occult hip pathology. Clin Sports Med 2001;20(4):801. [PMID: 11675888]
Kelly BT et al: Hip arthroscopy: current indications, treatment options, and management issues. Am J Sports Med 2003;31(6):1020. [PMID: 14623676]
Seldes RM et al: Anatomy, histologic features, and vascularity of the adult acetabular labrum. Clin Orthop 2001;Feb(382):232. [PMID: 11153993]
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Snapping Hip (Internal Coxa Saltans)
Essentials of Diagnosis
Prevention
Repetitive activities involving high hip flexion are the most common inciting factor leading to a painful internal snapping hip. Elimination of training exercises involving high hip flexion will often allow symptoms to improve. Stretching hip flexors prior to activity may be helpful. Although prevention of an internal snapping hip can be difficult, early recognition of the exacerbating activities, and elimination of these activities from the training routine can decrease the duration and extent of symptoms.
Clinical Findings
Symptoms of a snapping hip usually begin insidiously with a dull, deep catch or “clunk” in the groin with flexion and extension of the hip. The pain can be located anywhere below the ASIS to the hip flexion crease, and is often centered about the AIIS. The symptoms can be described as an uncomfortable vibration, catching, or locking. Runners often describe weakness or dysfunction that is particularly noticeable as they advance the trailing leg. With severe irritation of the iliopsoas tendon, athletes will use their hands to lift the leg as they get onto the examination table or into a car.
A careful history including the specifics of training activities and any change in the workout routine can be helpful in distinguishing a snapping hip from other causes of groin pain. In particular, a labral tear is more often associated with an acute injury or underlying morphologic bony abnormality that is usually evident on plain radiographs.
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Reproduction of snapping or clunking while taking the hip from a flexed, abducted, externally rotated (FABER) position to extension and neutral rotation is diagnostic of an internal snapping hip (Figure 2-14). This maneuver creates tension in the iliopsoas tendon as it is stretched across the iliopectineal eminence of the pelvis and femoral head and neck. The groin pain and clunk are often reproduced with each repetition of this maneuver. In addition to being perceived by the patient, snapping can often be heard and palpated in the groin by the examiner. Repetition of this maneuver will cause soreness in the groin, often characteristic of the athlete's pain.
Groin pain from an anterior labral tear or femoral–acetabular impingement occurs with the opposite maneuver of taking the hip from extension and neutral rotation to flexion, adduction, and internal rotation (FADIR). This maneuver brings the anterior superior femoral head and neck into proximity with the anterior superior acetabular labrum.
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Figure 2-14. A, B: Clunking or snapping with the pictured maneuver can occur at the lesser trochanter, femoral head, superior pubic ramus, or sacroiliac joint. The underlying problem with internal snapping hip is excess tension or inflammation of the iliopsoas mechanism. (Reproduced, with permission, from Dobbs et al: Surgical correction of the snapping iliopsoas tendon in adolescents. J Bone Joint Surg Am 2002;84:420. ) |
MRI of the hip can demonstrate abnormalities of the iliopsoas tendon and bursa, anterior hip capsule, and musculature of the iliopsoas mechanism. Findings are often subtle, so a high strength magnet that provides excellent resolution and imaging of both hips for comparison can be helpful.
Dynamic ultrasound can be diagnostic of snapping hip. This test is operator dependent.
Complications
Tendon rupture following paratendinous iliopsoas cortisone injection has not been reported. Temporary
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exacerbation of symptoms following injection can occur. If symptoms persist following injection the treating physician should consider other causes of groin pain with mechanical symptoms caused by intraarticular pathology. Investigation with MR arthrography may be warranted in this circumstance.
Care must be taken during open surgical intervention for a snapping hip to avoid direct injury to the femoral nerve. When the iliopsoas tendon has been identified, it should be tested with a nerve stimulator prior to recession. The lateral femoral cutaneous nerve is in the field of dissection. The patient should be warned that numbness in the anterior thigh is not uncommon following surgery. Weakness of hip flexion following recession of the iliopsoas tendon is expected, but should be temporary and disappear with rehabilitation. Prolonged weakness has been reported with complete release of the tendon from the lesser trochanter. For this reason, other surgical approaches should be considered in athletes.
Treatment
Avoidance of precipitating activities, particularly hip flexion greater than 90°, and NSAIDs are the mainstay of treatment.
A physical therapy program including stretching can be helpful. Modalities such as cryotherapy and electrical stimulation have been reported to be effective.
Steroid injection can relieve the symptoms of a snapping hip. The injection can be done with ultrasound, CT, or fluoroscopic guidance. A mixture of 40 mg of triamcinolone acetonide (Kenalog), 0.5 mL of 1% lidocaine, and 0.5 mL of 0.5% bupivicaine injected into the tendon sheath has been recommended. The procedure is done under local anesthetic. The spinal needle is placed over the superior medial quadrant of the femoral head and directed into the region of the iliopsoas tendon sheath and underlying bursa. Repeat injection can be performed if the first injection is partially or temporarily effective.
Surgery for a snapping hip is rarely necessary. When conservative measures fail and symptoms warrant, surgical intervention should be considered. The goal of surgery for a snapping hip is to decrease the tension in the iliopsoas tendon as it moves across the front of the hip joint and pelvis during flexion and extension of the hip. A secondary goal of surgery is to maintain the strength of the hip flexors.
Surgical strategies that have been recommended include open release near the insertion of the iliopsoas tendon to the lesser trochanter, open recession of the tendinous portion of the musculotendinous junction proximal to its insertion, and arthroscopic recession at either location. Release at the lesser trochanter has been associated with prolonged weakness of hip flexion. Arthroscopic recession proximal to the lesser trochanter by working through the anterior capsule of the hip joint to access the iliopsoas tendon has been described.
Prognosis
Symptoms from a snapping hip usually improve rapidly if the exacerbating drill or activity is avoided. With modification of activity, NSAIDs, and stretching, the athlete may be able to return to participation within 1–4 weeks. If rapid improvement does not occur, a steroid injection should be considered. The prognosis to full return to activity within 1–2 weeks following injection is good.
Return to Play
Return to elite athletic performance has been reported following surgical recession of the iliopsoas tendon. Recovery of strength sufficient for high level athletic activity is expected to take up to 6 months.
Dobbs MB et al: Surgical correction of the snapping iliopsoas tendon in adolescents. J Bone Joint Surg Am 2002;84-A(3):420. [PMID: 11886912]
Gruen GS et al: The surgical treatment of internal snapping hip. Am J Sports Med 2002;30(4):607. [PMID: 12130417]
Wahl CJ et al: Internal coxa saltans (snapping hip) as a result of overtraining: a report of 3 cases in professional athletes with a review of causes and the role of ultrasound in early diagnosis and management. Am J Sports Med 2004;32(5):1302. [PMID: 15262657]
Labral Injuries
Essentials of Diagnosis
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Figure 2-15. A 17-year-old high school cheerleader with a labral tear of the left hip. |
Prevention
The best way to avoid degenerative labral tears is to avoid repetitive activities that bring the femoral neck in forceful contact with the labrum (Figure 2-15). This is not possible for some athletes whose sports involve extremes of flexion, abduction, or rotation of the hip. Competitive golfers, figure skaters, martial artists, cheerleaders, dancers, and gymnasts cannot avoid these activities during training or competition.
Acute labral tears have been seen in high force or ballistic activities in an undertrained individual such as a high school dancer performing a jump-split or an unconditioned individual performing a leg press with heavy weights. Proper training, with a gradual increase in extreme positions or weights, may help to avoid traumatic labral tears.
It is not uncommon for female athletes to have acetabular dysplasia. The increased hip motion associated with dysplasia may help gymnasts and ballerinas to excel. These athletes may be more prone to injury from
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repetitive activities with extreme ranges of motion in a hip with a hypertrophic labrum and possibly some instability. Labral tears can progress to or be associated with arthritic deterioration of the hip joint, particularly in athletes with underlying dysplasia (Figure 2-16) or femoral–acetabular impingement (Figure 2-17).
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Figure 2-16. A 36-year-old former elite competitive gymnast with left hip pain. Note the mildly dysplastic acetabulum with a large superior-lateral acetabular cyst. This is indicative of separation of the labrum from the hyaline cartilage of the acetabulum. Slight narrowing of the cartilage space is also present. The potential for arthritic deterioration is high. |
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Figure 2-17. A 27-year-old National Football League lineman with right groin pain and difficulty getting down into his stance. There is underlying femoral–acetabular impingement that has caused a labral tear. There are signs of hip arthritis, including narrowing of the cartilage space, osteophytes, and loose bodies. |
Clinical Findings
Pain from a labral tear is usually felt in the groin or anterior hip. Athletes often indicate that their pain is located in front of and around the side of their hip by using the
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extended thumb and index finger or hand to grab the front and side of the hip. This has been called a “positive C-sign” because the extended thumb and index finger make a “C.” Pain from a labral tear can also radiate to or be felt in the buttock or posterior lateral hip region. Anterior labral tears are most common. There may be a correlation between anterior labral tears causing anterior (groin) pain and posterior labral tears causing posterior (buttock) pain.
Hip pain from a labral tear is often associated with mechanical symptoms of painful clicking or popping. Catching and locking can also occur with a torn labrum. As with other hip pathologies, the pain from a labral tear can radiate down the leg, most often from the groin down the anterior thigh toward the knee. It can also radiate down the medial thigh along the adductor muscle group.
Pain from a torn labrum can range from subtle, dull, activity-induced, positional pain that fails to improve with rest to severe constant pain that interferes with activities of daily living. Athletes with a torn labrum will seldom walk with a significant limp or require crutches for ambulation. They will frequently avoid certain positions or activities that provoke symptoms. Provocative positions usually involve flexion, abduction, and rotation of the hip. The positional pain frequently interferes with athletic performance.
Specific traumatic events such as twisting, falling, or other loads on the leg may precede the onset of symptoms. A traumatic labral tear can be caused by the application of force to the hyperextended, externally rotated hip. At times, the onset of symptoms is more insidious, without a sentinel event, particularly with degenerative labral tears. An athlete may experience lingering symptoms from a “groin pull” that are actually caused by a torn labrum.
Physical examination will usually allow the examiner to distinguish athletes with a torn labrum from those with a snapping hip. With the athlete supine, symptoms from a torn labrum are reproduced by bringing the hip into FADIR. This maneuver, which brings the femoral neck into contact with the labrum, is termed the “impingement test.”
Joseph McCarthy has described a variation of the Thomas test that is analogous to McMurray's test for a meniscal tear of the knee. With the athlete supine, both hips are flexed, locking the pelvis. The painful hip is then extended with the hip first in external rotation, then in internal rotation. Reproduction of a painful click constitutes a positive McCarthy sign. Groin pain with a rise in a resistive straight leg has been described as evidence of a labral tear. This test is not specific for a torn labrum however, and can be positive with other causes of intraarticular hip pathology.
It can be challenging to confirm the presence of a torn acetabular labrum with radiographic imaging. Plain radiographs of the hip should be reviewed. An anteroposterior view of the pelvis allows comparison of the affected hip to the opposite side. A frog lateral view of the involved hip should be ordered. In a hip with normal morphology these radiographs will often be normal. These views should be screened for the presence of acetabular dysplasia. Intraosseous cysts, seen in patients with long-standing labral tears, are usually indicative of associated chondromalacia or separation of the junction of the labrum and acetabular cartilage (Figure 2-16). These cysts are most commonly located at the superior lateral edge of the acetabulum.
The most common radiographic abnormality in a hip with femoral–acetabular impingement is a “pistol-grip” deformity, or loss of concavity of the superior and anterior femoral neck (Figure 2-13). This developmental abnormality is associated with degenerative labral tears. Intraosseous cysts in the femoral head located at the anterior superior junction of the head and neck (herniation pits) can be seen in hips with impingement. One study from the Mayo Clinic found that at least one structural abnormality of the hip was detectable on conventional radiographs in 87% of patients with acetabular labral tears. This review included all patients seen over a 6-year period of time and was not specific for labral tears sustained during sport.
Plain MRI is unreliable either in confirming the presence of a torn labrum or in ruling it out. A paralabral cyst is, however, strong indirect evidence of a torn labrum. Accuracy is improved significantly with MR arthrography, the diagnostic test of choice. MR arthrography is technique dependent (Figure 2-18). An arthrogram of the hip with gadolinium should be followed by an MRI done with surface coils, with a high-resolution scanner. A protocol specific for imaging the labrum, with cuts in the oblique sagittal plane of the femoral neck, is helpful (Figure 2-19).
CT scans and bone scans are generally not helpful in confirming the diagnosis of a torn acetabular labrum. Because of the significant false-negative rate of radiographic imaging techniques, including MR arthrography, it is reasonable to recommend hip arthroscopy for an athlete with symptoms and a physical examination suggestive of labral tear, even with a normal MR arthrogram, or without performing MR arthrography.
A hip block, injection of the hip joint with a local anesthetic under fluoroscopic guidance, can be helpful in deciding whether an intraarticular source of pain exists. Temporary relief of typical pain is supportive of intraarticular pathology as the source of the athlete's symptoms (Figure 2-18).
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Figure 2-18. Hip arthrogram performed with fluoroscopic guidance using isovue and gadolinium. The superior lateral edge of the labrum is shown with arrows. Note the dye in the medial acetabular fossa that tracks along the articular cartilage of the hip. Addition of local anesthetic can be useful to confirm the presence of intraarticular pathology. Steroids can be injected at the time of the arthrogram, if clinically indicated. This athlete had a torn labrum that is not seen on the arthrogram, but was visible on the subsequent MRI. |
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Figure 2-19. An MRI protocol specific for the diagnosis of labral tears is helpful. This image demonstrates sagittal cuts that are taken in the oblique plane of the femoral neck. |
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Clinical examination is the most accurate way to diagnose intraarticular pathology in the hip. The diagnostic accuracy of a clinical examination has been compared with MRI, MR arthrography, intraarticular injection, and arthroscopy. With arthroscopy as the gold standard, clinical assessment had a 98% accuracy rate in detecting intraarticular abnormality. MRI demonstrated a 42% false-negative and a 10% false-positive rate and MR arthrography had an 8% false-negative and 20% false-positive rate. Response to intraarticular injection as an indicator of intraarticular abnormality had a reliability of 90%. The study was not specific for labral tears, but included all intraarticular pathology.
Complications
There is no information in the literature regarding the natural history of labral tears. The risk for progressive arthritic deterioration of the hip joint with or without arthroscopic treatment is not known. For this reason, surgical treatment should be reserved for athletes in whom symptoms or restriction of activity are intolerable, or athletic performance is significantly impaired. The mere presence of a torn labrum on MR arthrography does not indicate the need for hip arthroscopy.
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Figure 2-20. An arthroscopic view of the hip demonstrating an anterior labral tear in the cheerleader pictured in Figure 2-15. A posterior superior flap tear of the labrum was debrided during hip arthroscopy with a shaver and flexible thermal probe. (The femoral head is pictured on the bottom, the acetabular fossa is in the lower right-hand corner, the acetabular cartilage is in the middle, and the labrum is on the top left.) |
Complications associated with hip arthroscopy include the risk of surgery with general anesthesia. Iatrogenic injury to the labrum and articular cartilage can occur. Instrument failure or breakage is possible. Traction must be applied to the leg during hip arthroscopy. This places the nerves of the leg at risk for traction injury. Direct injury to the sciatic and lateral femoral cutaneous nerves from portal placement is possible.
Treatment
Labral tears usually do not respond to conservative treatment. Physical therapy can be helpful if there is significant associated muscle spasm or gait abnormality. NSAIDs can reduce associated inflammation, which at times will decrease symptoms. Neither will improve the underlying source of inflammation and mechanical symptoms. Definitive treatment for a torn labrum is hip arthroscopy.
Hip arthroscopy allows visualization of the labral tear, confirming the diagnosis (Figure 2-20). The goal of arthroscopic treatment of a torn labrum is to relieve pain by eliminating the unstable flap tear that causes discomfort (Figure 2-21). The surgeon seeks to debride all torn tissue and leave as much healthy labrum intact as possible (Figure 2-22). Hip arthroscopy also allows
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visualization of other sources of hip pain and mechanical symptoms, including the articular cartilage of the acetabulum and femoral head, the ligamentum teres, and the capsule.
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Figure 2-21. Picture from hip arthroscopy of a 26-year-old physician's assistant with an anterior superior labral tear sustained while rock climbing. (The femoral head is on the bottom, the hip capsule to the left, and the labrum on the right.) |
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Figure 2-22. An arthroscopic picture of a degenerative labral tear in a 33-year-old female former National Collegiate Athletic Association volleyball player. (The femoral head is on the lower right, the labrum is on the top, and the labral tear is to the left.) |
For an athlete with severe and constant hip pain, indicating an inflamed hip joint, there is occasionally a role for intraarticular steroid injection. This is usually a temporizing measure.
Prognosis
The prognosis for arthroscopic treatment of isolated, acute traumatic labral tears is good. Good to excellent results have been reported in 80–90% of patients. Return to competition, even at the elite level, is possible. Persistent popping, particularly with certain positions or activities, is common, even following otherwise successful hip arthroscopy. The athlete facing hip arthroscopy for a torn labrum should be forewarned of this possibility.
The prognosis for athletes with degenerative tears, those associated with repetitive high-risk activities, is relatively poor for return to high level competition. The prognosis is significantly worse if chondromalacia is seen at arthroscopy.
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Figure 2-23. Following successful periacetabular pelvic osteotomy, the now 22-year-old male pictured in Figure 2-12 is pursuing a minor league baseball career. The screws were removed and the osteotomy solidly healed before release to full activity. |
Following hip arthroscopy, athletes remain touch-down weight bearing for a short period of time, usually from 2 days to 2 weeks. Range of motion exercises are emphasized during the first 2–6 weeks following arthroscopy. Return to full athletic activity can usually occur from 6 to 12 weeks following hip arthroscopy.
There is limited information in the literature regarding the prognosis following arthroscopic treatment of a labral tear in an athlete with an underlying bony abnormality. Persistent symptoms would be expected with significant acetabular dysplasia or retroversion, or femoral–acetabular impingement. Surgical treatment to address these problems, such as periacetabular osteotomy (Figure 2-23) or surgical dislocation of the hip, has been described. Surgical dislocation, requiring a trochanteric osteotomy, can also allow repair of a bucket-handle labral tear (Figure 2-24).
Return to Play
There is no information in the literature on return to competitive athletics following these surgical procedures.
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Figure 2-24. A 17-year-old soccer player and football kicker following surgical dislocation of the right hip, removal of the femoral neck impingement lesion, and repair of a bucket-handle labral tear. Right hip pain and popping improved, but the patient was unable to return to sports due to left hip pain. Note the loss of concavity of the left superior femoral neck, and improved concavity of the superior femoral neck of the right hip following surgery for femoral–acetabular impingement. |
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Byrd JW, Jones KS: Diagnostic accuracy of clinical assessment, magnetic resonance imaging, magnetic resonance arthrography, and intra-articular injection in hip arthroscopy patients. Am J Sports Med 2004;32(7):1668. [PMID: 15494331]
O'Leary JA et al: The relationship between diagnosis and outcome in arthroscopy of the hip. Arthroscopy 2001;17(2):181. [PMID: 11172248]
Siebenrock KA et al: Abnormal extension of the femoral head epiphysis as a cause of cam impingement. Clin Orthop 2004;Feb(418):54. [PMID: 15043093]
Wenger DE et al: Acetabular labral tears rarely occur in the absence of bony abnormalities. Clin Orthop 2004;Sep(426):145.