This article provides concise and up-to-date information on the most common hip pathologies that affect adolescent athletes. We cover the evaluation and treatment of avulsion injuries, stress fractures, slipped capital femoral epiphysis (SCFE), femoroacetabular impingement, developmental dysplasia of the hip, Legg-Calve-Perthes disease, and coxa saltans focusing on minimizing advanced imaging and using conservative therapy when applicable. Although this is not an all-encompassing list of disorders, it is key to understand these hip pathologies because these injuries occur commonly and can also have detrimental complications if not diagnosed and addressed early, especially SCFE and femoral neck stress fractures.
Key points
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Adolescents often have referred knee pain with hip pathology; therefore, a physical examination of the hip is necessary during initial evaluation of knee complaints.
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Radiographs are the diagnostic imaging modality of choice with advanced imaging being used when radiographs are equivocal, such as with suspected stress fractures and slipped capital femoral epiphysis (SCFE) (pre-slip).
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Learning radiographic measurements and relationships is necessary for diagnosing hip pathology.
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Early, proper diagnosis and treatment with conservative measures can avoid long-term complications and the need for surgery in many adolescent hip pathologies.
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Failure to diagnosis developmental dysplasia of the hip, femoral neck stress fractures, Legg-calve-Perthes disease, and SCFE can lead to detrimental osteoarthritis, completed fractures and avascular necrosis of the femoral head.
Introduction and etiology
Adolescent hip injuries encompass a wide range of disorders that are the result of not only acute trauma but also the manifestation of abnormal development. They commonly occur at a rate of approximately 53 per 100,000 athlete exposures based on National Collegiate Athletic Association reports. It is important to note that sports involving explosive activities, as seen in soccer, ice hockey, and football, have a higher incidence of hip injuries. The temporal aspect of a person’s hip pain also can provide insightful clues as to the underlying pathology. The acute onset of pain may represent a fracture or soft tissue tear, whereas an insidious onset of pain may be related to developmental anatomy. The location of the athlete’s pain can help determine the source, as groin pain is likely to represent intra-articular pathology. Lateral-based pain should raise concerns for anatomically pertinent pain generators, such as Iliotibial (IT) Band syndrome or abductor fatigue syndrome. In younger patients, it is important to note that pain in the knee may be referred from the hip. Other important historical factors to assess for include the female athlete triad, family history of developmental disorders, or endocrinopathies.
Physical examination
The physical examination of the hip consists of gait analysis, hip range of motion (ROM), muscular strength, and provocative testing to help elucidate a patient’s potential pathology. The first assessment is to determine the ability to weight bear and abnormalities such as an antalgic gait and a Trendelenburg gait. A Trendelenburg gait occurs when there is associated hip abductor weakness and results in lateral trunk flexion to the affected side as the patient shifts their center of gravity to compensate for the associated abductor weakness. Assessing hip ROM, specifically internal and external rotation, should be performed both prone to assess for femoral version, and supine with the hip flexed and extended. Dynamic testing of hip ROM can also be used to identify coxa saltans. Specialized examination maneuvers can be used to assist with differentiation between intra-articular and extra-articular pathologies. Flexion, adduction, and internal rotation (FADIR) is associated with femoroacetabular impingement, especially if there is a loss of associated internal rotation. Painful log roll test with the hip extended has been advocated to raise the suspicion for intra-articular pathology. Flexion, abduction, and external rotation (FABER) can be used to diagnose posterior femoroacetabular impingement (FAI) or sacroiliac syndrome. It is considered positive for hip pathology when it produces groin pain or increased difference (>4 cm) between knee-to-table distance when compared with the contralateral side. In addition, signs of hypermobility, including elevated Beighton Scores or anterior hip pain with the hip externally rotated in extension may help elucidate hip instability as the source of the problem.
Imaging
Imaging of the adolescent hip starts with the following radiographs: an anteroposterior (AP) pelvis, a false profile view, and a frog-leg or Dunn view. The decision to escalate to advanced imaging is mainly necessary for preoperative planning or to rule out injuries not seen on plain films. An MRI is used to visualize soft tissues, bony edema, and osteonecrosis. A computed tomography (CT) scan with 3-dimensional (3D) reconstructions provides improved bony anatomy visualization when compared with radiographs but should be completed with a low-dose protocol to limit radiation exposure.
Apophyseal avulsions
Apophyseal avulsions are a noncontact injury resulting from rapid accelerations and decelerations during high-impact athletics. Repetitive stress on the musculoskeletal unit coupled with the intrinsic weakness of the epiphyseal plates explains why this fracture affects adolescents. The same mechanism, in skeletally mature adults, usually results in a muscle or tendon injury.
This injury typically affects 14-year-old to 17-year-old athletes with a predilection for boys over girls. The most common sports being soccer, football, gymnastics, and track. Acute symptoms include sudden, shooting pain and functional weakness. On examination, edema, ecchymosis, localized tenderness, and pain with passive ROM are often present. , Diagnosis is confirmed with radiographs with the most common locations in decreasing order being the anterior inferior iliac spine (AIIS), the ischial tuberosity, the anterior superior iliac spine (ASIS), the lesser trochanter, and the pubic symphysis ( Table 1 ). The degree of displacement is restricted by the surrounding periosteum and fascia.
| Apophysis | Common Muscle Avulsion |
|---|---|
| Anterior inferior iliac spine (AIIS) | Rectus femoris |
| Ischial tuberosity | Hamstrings |
| Anterior superior iliac spine (ASIS) | Tensor fascia lata, sartorius |
| Lesser trochanter | Iliopsoas |
| Pubic symphysis | Rectus abdominis |
Conservative management is typically chosen for all avulsions with <2 cm of displacement. Rest, ice, and nonsteroidal anti-inflammatory drugs (NSAIDs) are used initially, followed by protection of weight bearing with crutches until symptom resolution. The athlete may return to sports after progressing through physical therapy involving isometric stretching and strengthening exercises. , Traditionally, surgical intervention is reserved for avulsions with >2 cm of displacement due to high risk of developing a symptomatic nonunion, chronic pain, or diminished function. Fixation is achieved by screws or suture anchors depending on surgeon preference and the size of the avulsed fragment. However, a recent meta-analysis by Eberbach and colleagues introduced some controversy to the historical treatment algorithm by showing an improved overall success rate in patients receiving surgery (88%) compared with those undergoing conservative treatment (79%) with a statistically significant return to sports rate of 92% and 80%, respectively. After stratifying using a cutoff of 1.5 cm versus 2.0 cm for operative intervention, their study showed an 84% success rate in operative patients versus 50% in the conservative group ( P = .04).
Stress fractures
Stress fractures occur in 2 generalized categories: fatigue fractures and insufficiency fractures. Fatigue fractures are the result of abnormal forces on normal bone, whereas insufficiency fractures result when normal forces act on abnormal bones. Typically, adolescents develop fatigue fractures due to repetitive microtrauma, whereas elderly patients develop insufficiency fractures. , The femoral neck encompasses 5% to 7% of all adolescent stress fractures, which is secondary only to the tibia. Girls who participate in long-distance running are more likely to develop femoral neck stress fractures than their male counterparts. This higher prevalence in female individuals is also seen in military recruits.
While assessing a female athlete with a femoral neck stress fracture, it is important to evaluate for the female athlete triad, consisting of amenorrhea, nutritional deficiencies or disordered eating, and osteopenia. Other risk factors include corticosteroid use, smoking, and hypermetabolic endocrinopathies. On examination, patients typically develop an insidious, progressive hip pain that may be localized to the groin and is intensified with impact activity. As symptoms worsen, pain will be elicited with hip internal rotation and with the hop test. Early in the disease process, radiographs have a low sensitivity of detecting an abnormality, and a rapid sequence MRI is a more sensitive imaging modality to assess for a stress fracture. Bony edema is what can be best visualized on T2-weighted images, but on T1-weighted sequences the presence and location of a fracture line largely determines the treatment ( Fig. 1 ).
If the fracture remains confined to the compression side, which fortunately for adolescent athletes is more common as compared with tension-sided stress fractures, then conservative therapy can be attempted with toe-touch weight bearing for at least 4 weeks, NSAIDs, and physical therapy to increase core and hip strength. If the adolescent fails conservative treatment or has a fracture line that involves any component of the tension side of the femoral neck, surgical intervention is necessary. Surgical options include either percutaneous screw fixation or other internal fixation devices to prevent propagation of the stress fracture into a complete femoral neck fracture. With either treatment, correcting underlying endocrinopathies, poor nutritional status, and osteoporosis is necessary to prevent future stress fractures and to promote adequate healing.
Slipped capital femoral epiphysis
Slipped capital femoral epiphysis (SCFE) is one of the potentially devastating hip disorders that occurs in adolescent athletes. It has a higher prevalence in African American boys with elevated body mass indexes. Frequently, it is a unilateral process, but it will be evident bilaterally in 20% to 50% of patients. Those who suffer from bilateral disease often have an underlying endocrinopathy, most commonly being hypothyroidism, renal osteodystrophy, growth hormone deficiency, and panhypopituitarism. Younger age (<10 years old) and low height and/or weight (<10th percentile) warrants further workup for an endocrinopathy, as SCFE may be their initial presenting symptom
SCFE occurs most commonly with anterior displacement of the metaphysis relative to the epiphysis, with subsequent retrotorsion of the epiphysis. It has been associated with a pubertal growth spurt, trauma, and relative acetabular retroversion. , Adolescents typically present with an insidious onset of groin pain that is achy in nature and is exacerbated by physical activity. Like many hip disorders in adolescents, this pain can be referred to the knee. On examination, these patients ambulate with an external foot progression angle, have obligate hip external rotation with hip flexion, and have pain on any attempts of hip internal rotation. Per the Loder Classification, the ability to bear weight defines stability. This distinction is important because a stable SCFE has an osteonecrosis rate of less than 10% while an unstable SCFE has osteonecrosis rates reported up to 47%. ,
Plain radiographs, including an AP pelvis and a lateral hip, will show that the Klein line does not intersect the epiphysis ( Fig. 2 ). MRI is sometimes obtained if the radiographs are normal in the “pre-slip” condition. It will demonstrate edema around the physis as evidenced by hyperintensity on T2-weighted sequences and hypointensity on T1-weighted sequences ( Fig. 3 ).
