Hip pain in the adolescent athlete is a common source of functional impairment and can limit athletic performance. In the past, many intra- and extra-articular hip abnormalities went unrecognized and were left untreated because of insufficient diagnostic imaging and limited surgical options. However, over the past 20 years, there has been a tremendous expansion research, and the understanding of the etiology of hip pain among such athletes has grown. Improvements in imaging modalities and technical innovations have led to greater diagnostic insights and creative new treatment strategies. This article explores the etiology and treatment of hip pain in the adolescent athlete.
Key points
- •
A thorough history can often uncover important clues about the etiology of pain, and a well-directed interview is crucial to understanding primary versus secondary pain generators in the hip and pelvis.
- •
The clinician treating hip pain in the adolescent athlete should become familiar with performing a thorough hip examination and interpreting radiographic images. The physician should recognize that a comprehensive hip examination includes evaluation of gait, the spine, abdominovisceral structures, and other musculoskeletal regions.
- •
Hip pain in the adolescent athlete often reflects a number of concomitant pathologies, and a thorough awareness of the distinct characteristics of each is important to establishing a proper diagnosis and treatment strategy.
- •
Biomechanical relationships between the hip joint, periarticular soft tissue envelope, and central pelvic structures must be understood to distinguish between primary pathologies and compensatory injury patterns.
- •
Underlying systemic, rheumatologic, or oncologic conditions should always be considered in the young athlete, even when the injury seems to reflect a musculoskeletal etiology.
Introduction
Establishing an accurate diagnosis for the adolescent athlete with hip pain can be challenging. Complex pathomechanical interactions within the hip joint, compensatory extra-articular injuries, and the central watershed location of the hip often result in an obscure clinical picture without a clear singular diagnosis. Open physes among athletes of this age group are prone to overuse enthesopathies, or traumatic avulsions in higher-energy injuries. Morphologic alterations in the proximal femur or acetabulum can result in anatomic conflict during dynamic activities, and may result in debilitating chondral and labral injuries as a young athlete develops. In addition to physeal injuries and femoroacetabular impingement, repetitive microtrauma, or isolated traumatic events can lead to a number of other soft tissue and bony abnormalities that may contribute to hip pain.
Introduction
Establishing an accurate diagnosis for the adolescent athlete with hip pain can be challenging. Complex pathomechanical interactions within the hip joint, compensatory extra-articular injuries, and the central watershed location of the hip often result in an obscure clinical picture without a clear singular diagnosis. Open physes among athletes of this age group are prone to overuse enthesopathies, or traumatic avulsions in higher-energy injuries. Morphologic alterations in the proximal femur or acetabulum can result in anatomic conflict during dynamic activities, and may result in debilitating chondral and labral injuries as a young athlete develops. In addition to physeal injuries and femoroacetabular impingement, repetitive microtrauma, or isolated traumatic events can lead to a number of other soft tissue and bony abnormalities that may contribute to hip pain.
History
An accurate diagnosis for an adolescent athlete with hip pain can usually be gained through a focused clinical history. Of primary concern is whether the onset of symptoms was acute and caused by a single traumatic event, related to repetitive athletic activities, or unrelated to athletic endeavors altogether. Higher-energy athletic injuries to the hip and pelvis frequently involve the biomechanically vulnerable physes and surrounding soft tissues, rather than deeper intra-articular structures. Young elite-level athletes are under increasing pressure to commit to a single sport at a young age, and train throughout the year to optimize their performance in that sport. The literature is replete with the unfortunate consequences of multiple exposure hours to the skeletally immature athlete. Attritional injuries to the acetabular labrum or articular cartilage, stress reactions/fractures, and injuries to the surrounding myotendinous envelope are injury patterns that are linked to repetitive overuse. Fluctuations of symptoms with a diurnal pattern may reflect an underlying inflammatory, systemic, or rheumatologic condition. Pain that is not reproducible with strenuous activities, is not reported with a predictable pattern, and is associated with other vague constitutional symptoms should prompt concern for an underlying systemic etiology ( Figs. 1 and 2 ). Inquiring about age at symptomatic onset and development of secondary sex characteristics can yield valuable information about the state of skeletal maturity and certain age-specific cues that may aid in making an accurate diagnosis. Legg Calve Perthes (LCP) and slipped capital femoral epiphysis (SCFE) are 2 conditions that have characteristic age associations and may demonstrate many clinical features similar to acetabular labral tears, chondral injuries, or even meniscal–chondral injuries of the knee.
Location
The location of an athlete’s hip pain should always be ascertained and may reveal important clues that reflect the etiology of the primary pain generator. A layer concept has been proposed to help clinicians understand the link between intra- and extra-articular pain generators, pain topography, and compensatory injury patterns. Patients with an intra-articular pain source often describe the location of their pain in a C-shaped arc that courses from the anterior groin, over the lateral hip, to the buttock region. Although many potential injury patterns exist (and may coexist), anterior hip or groin pain should arouse suspicion of anterosuperior (ASIS) or anteroinferior (AIIS) iliac spine apophysitis, iliopsoas or adductor tenosynovitis, symptomatic femoroacetabular impingement (FAI) with anterosuperior chondro–labral injury, or athletic pubalgia.
Lateral hip pain should elicit concern for pathology within the abductor complex (gluteus medius and minimus, common in cross-country runners), trochanteric bursal irritation, or friction from iliotibial band (ITB) contracture. Adolescents with acetabular dysplasia frequently present with lateral hip pain caused by fatigue overload of the abductor complex secondary to poor lateral acetabular containment and stability. Although lateral hip pain has traditionally been associated with extra-articular pain generators, emerging knowledge suggests that intra-articular pathology may contribute to lateral hip pain much more commonly than previously believed. Isolated posterior buttock pain may suggest lumbosacral pathology or deep gluteal pain syndrome with associated entrapment neuritis of the sciatic nerve, piriformis, and short external rotator contracture.
Character/quality
The character and quality of pain may also help designate an appropriate diagnosis. Pain may be sharp and mechanical or dull and aching. Coxa saltans (ie, snapping hip syndrome) may be associated with iliopsoas contracture and tenosynovitis (anterior) or ITB contracture and abrasion (lateral). Patients with symptomatic ITB snapping often complain that their hip is dislocating and usually can reproduce their symptoms. Iliopsoas snapping is common in the setting of atraumatic hip instability because of anterior acetabular deficiency and increased secondary demand on the anterior hip capsule and anterior soft tissue stabilizers. Catching or mechanical locking may result from unstable labral–chondral injury or intra-articular loose bodies. Pain that is of an aching quality may reflect synovitis, myofascial irritation, or stress reaction.
Temporal factors
The duration and factors associated with the production of pain are key elements of a thorough history. Most soft tissue sprains or minor myofascial injuries generally resolve over a 4- to 6-week course and should demonstrate consistent step-wise improvement. Injuries that persist beyond this period should motivate additional workup to evaluate for a more significant injury. Most hip pain is predominantly static or dynamic. Dynamic pain is often reproduced with athletic training or functional sport-specific activities such as cutting, pivoting, impact landing, or explosive ballistic movements. Symptomatic FAI with labral–chondral injury, hip instability, or apophysitis characteristically produce a dynamic type of hip pain. Static pain often occurs in the absence of high-energy motion and may result from compromise of the neuroproprioceptive feedback arc or poor muscular coordination and cocontraction. Static pain may be associated with underlying systemic pain sources (eg, autoimmune, rheumatologic, connective tissue, or dysfunction).
Physical examination
Physical examination of the young athlete with hip pain is essential to further support or refute the suspected diagnosis and gain a greater understanding of the anatomic contributors to hip dysfunction. A meticulous approach to examining the hip has been thoroughly described and proceeds in a layered approach. A complete examination includes evaluation of gait and physical tests in the standing, seated, supine, decubitous (lateral), and prone. Specialized tests are utilized to clarify whether the pain source is intra- or extra-articular.
Gait/standing
Antalgic gait patterns may include a hip-extension avoidance gait with decreased stride length. Limiting push-off and terminal extension is a protective mechanism to minimize pain from anterior capsular contracture and stretch on the irritable anterior soft tissues. Abductor compromise may manifest as a Trendelenburg gait pattern, although this is less common in adolescents groups. Exceptions would include athletes suffering from chronic ITB contracture or snapping and abductor inhibition. Instructing the patient to attempt a single leg lunge may reveal subtle dynamic abductor imbalance manifesting as pelvic drop or lateral trunk flexion upon execution. In the standing position, patients with ITB contracture and snapping can usually reproduce their symptoms, producing a visually impressive snap as the contracted posterior third of the ITB subluxes back and forth across the greater trochanter.
Seated/supine
A seated examination forces the pelvis into a stable position and can be used to evaluate hip range of motion (ROM). Patients with deep gluteal pain syndromes often sit with an avoidance posture that limits direct pressure on the deep gluteal structures. Supine examination focuses on observation of skin and soft tissues for ecchymosis, abrasions, swelling, or gross deformity. High-energy bony or soft tissue avulsion injuries may incur significant disruption of surrounding vascular structures and produce bruising, hematoma, and swelling. Palpation of the iliac crest, ASIS, AIIS, ischium, pubis, and greater trochanteric physes may reveal point tenderness suspicious for avulsion injury. ROM testing should be repeated in the supine position and conducted with the contralateral hemipelvis stabilized. Comparative measurements should be taken and discrepancies noted. Leg lengths should be grossly assessed by comparing the height of the medial malleoli with the pelvis in the relaxed and balanced positions.
Special tests
Special examination tests can be used to differentiate between a variety of intra- or extra-articular pain generators. A log-roll test is useful to detect capsulitis and can also reveal capsular contracture with FAI or severe synovitis. In a supine position, the affected hip is rolled back and forth, with the leg in a neutral position. Pain or limited motion constitutes a positive test. A similar dial test can be performed in the supine position to diagnose capsular laxity in patients with hip instability. An external rotation force is applied to the effected leg and released. Capsular tone is assessed visually as the leg rebounds into internal rotation (IR). Comparative testing is conducted on the contralateral limb, and if rebound IR is limited on the affected leg and is asymmetrical compared with the unaffected hip, the test is considered positive. Anterior impingement testing is generally performed to assess for anterosuperior labral–chondral injury and FAI. The affected hip is brought into flexion past 90° with variable degrees of IR and adduction (FADIR). A test is considered positive when pain is elicited and ROM compromised. The scour test is a dynamic test that places the hip into a similar provocative position with compression and sequential IR and external rotation (ER), producing pain in the presence of intra-articular pathology. FAI may effect the hip anteriorly with FADIR maneuvers or the lateral hip with a more lateral pattern of pathomorphology. Passive abduction with IR or ER would elicit pain and correspond with activity-related symptoms (horseback riding, martial arts, dance). Effectively, the zone of impingement can be dialed in based on the position of anatomic conflict or physical abutment during ROM testing. Pain primarily with straight and deep passive hip flexion may suggest an extra-articular source of impingement between the AIIS and femoral neck, and is common in dancers and martial artists. Manual muscle strength testing should be performed in the supine position with the knee both flexed and extended to isolated strength deficits of the hip flexor complex (tensor fascia lata [TFL] plus iliopsoas (IP) and rectus femoris) versus individual hip flexors.
Pain may also be generated with flexion, abduction, and ER (FABER). Posterior pain with FABER testing is usually associated with sacroilitis, while anterior hip pain is commonly attributed to iliofemoral ligament or iliopsoas contracture and tenosynovitis. A positive FABER test is associated with side-to-side asymmetry in ROM and pain. While performing FABER testing, a dynamic examination can be performed to assess for IP snapping. The hip is slowly brought from a position of slight flexion, abduction, and ER to extension and IR. A reproducible grinding, clicking, or clunking can be palpated and usually heard. This is typically painful for the patient. Pain with resisted abdominal activation and/or hip adduction suggests athletic pubalgia with injury to the rectus abdomens or tendinous origin of the adductor complex. In the supine position, abdominal lower quadrant palpation superior to the inguinal ligament should also be performed to determine if there may be abdominal visceral pathology contributing to pain.
Decubitous/prone
With the patient lying on his or her side in a decubitous position, the abductor and deep gluteal complex can be palpated for points of tenderness indicating trochanteric bursal irritation, gluteus medius/minimus pathology, or piriformis/short external rotator irritation. The sacroiliac joint and lumbosacral spine can also be inspected in the lateral position. Ober test is performed by allowing the affected hip (top hip) to passively extend and assessing for contracture or inability to passively adduct. Manual muscle strength testing should be performed with the knee alternatively extended and flexed to isolate abductor complex strength (knee straight for glut max/TFL plus gluteus medius/minimus) versus isolated gluteus medius/minimus (knee flexed). Prone examination can be conducted to gain further clinical information on the integrity of the common hamstring (biceps femoris, semimembranosis, and semitendinosis), gluteal complex, and the ischial tuberosity.
Imaging
Radiographs
Appropriate imaging of the injured adolescent hip and pelvis begins with a dedicated plain radiographic series. A well centered anteroposterior (AP) pelvis (coccyx centered 1 cm above pubis without rotation) and cross-table or frog leg lateral view are essential for a basic radiographic interpretation of bony structures about the hip. Physeal injuries to the ASIS, iliac crest, ischial tuberosity, pubis, and greater and lesser trochanters can be detected on these views. SI joint narrowing or sclerosis (ankylosing spondylitis), and bony abnormalities of the iliac wings (bony lesions or traumatic injuries) are also apparent with this series. An AP pelvic radiograph provides a crude representation of acetabular version and proximal femoral geometry. Morphologic features characteristic of FAI (ie, Cam-type FAI: aspherical femoral head-neck junction, pistol-grip deformity, or decreased femoral head–neck offset; pincer-type FAI: cross-over sign, acetabular retroversion, ischial spine sign) are grossly depicted on AP and lateral views. Acetabular volume, which is a proxy for femoral head containment or acetabular dysplasia, is represented by measuring a lateral center edge angle (LCEA). A false profile view is better suited to demonstrate ASIS or AIIS avulsion injuries and judge the degree of anterior acetabular coverage (anterior center-edge angle, ACEA). An extended femoral neck or Dunn view can be obtained with the hip flexed 45° or 90° and slightly abducted, to give a more accurate representation of Cam-type FAI variants with their characteristic femoral neck prominence (alpha angle >55°).
Ultrasound
Musculoskeletal ultrasound (MSUS) has emerged as a useful diagnostic tool with the ability to provide real-time dynamic imaging and feedback during provocative testing. Advantages include convenient in-clinic use with the ability to perform diagnostic evaluation of both intra- and extra-articular structures with high definition. Disadvantages of MSUS include user dependence and a significant learning curve. Dynamic impingement and instability testing can be performed in real time with concomitant visualization of key periarticular soft tissues such as ITB and IP. High-fidelity units can detect chondral, labral, and synovial abnormalities with high sensitivity and accuracy, and may eventually supplant the need for magnetic resonance imaging (MRI). MSUS also facilitates procedural interventions such as diagnostic and therapeutic intra- and extra-articular hip injections. Ultrasound-guided diagnostic injections are an extremely useful adjunct to clinical examination and can help identify the primary pain generator for a specific clinical scenario. Once an accurate diagnosis is established, an appropriate treatment strategy can be implemented.
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) offer detailed information regarding the integrity of intra- and extra-articular soft tissue structures about the hip. Traditional 1.5 T (1.5 T) and newer 3 T magnets produce high quality images and remain the gold standard for diagnosing acetabular labral and chondral pathology. Extra-articular injuries to the periarticular soft tissue envelope, stress reactions of the pelvis or hip, and intra-articular pathologies are all demonstrated with high diagnostic yield. The addition of intra-articular contrast, such as gadolinium, may further enhance the diagnostic accuracy of an MRI scan. Several studies have demonstrated higher sensitivity and specificity and potential advantages of MRA over MRI for detection of intra-articular pathologies. However, with advances in imaging techniques and technology (3 T scanners), noncontrast magnetic resonance units are approaching equivalence for detecting intra-articular hip pathology.
Computed Tomography
Computed tomography (CT) scans are most useful for characterization of bony avulsions or morphologic alterations in acetabular or proximal femoral anatomy. In the presence of FAI, CT scans can provide further definition of bony morphology and serve as a useful adjunct to other radiographic studies for preoperative tempting and planning ( Fig. 3 ). Acetabular dysplasia may involve only a portion of the acetabulum or may be more global in its involvement. CT characterization is helpful to determine the severity of the dysplasia and for planning corrective osteotomies. Slices can be made through the distal femur to calculate proximal femoral version and should be considered, along with 3-dimensional reconstructions, to gain a complete understanding of the biomechanical influences on the weight-bearing articular surface of the hip joint.
Full access? Get Clinical Tree
