The assessment of athletic hip injury

Experimental modification of morphology reveals the effects of the zygosphene-zygantrum joint on the range of motion of snake vertebrae

Variation in joint shape and soft tissue can alter range of motion (ROM) and create trade-offs between stability and flexibility. The shape of the distinctive zygosphene-zygantrum joint of snake vertebrae has been hypothesized to prevent axial torsion (twisting), but its function has never been tested experimentally. We used experimental manipulation of morphology to determine the role of the zygosphene-zygantrum articulation by micro-computed tomography (μCT) scanning and 3D printing two mid-body vertebrae with unaltered shape and with the zygosphene digitally removed for four species of phylogenetically diverse snakes. We recorded the angular ROM while manipulating the models in yaw (lateral bending), pitch (dorsoventral bending) and roll (axial torsion). Removing the zygosphene typically increased yaw and dorsal pitch ROM. In the normal vertebrae, roll was <2.5 deg for all combinations of pitch and yaw. Roll increased in altered vertebrae but only for combinations of high yaw and ventral pitch that were near or beyond the limits of normal vertebra ROM. In the prairie rattlesnake and brown tree snake, roll in the altered vertebrae was always limited by bony processes other than the zygosphene, whereas in the altered vertebrae of the corn snake and boa constrictor, roll ROM was unconstrained when the pre- and post-zygapophyses no longer overlapped. The zygosphene acts as a bony limit for yaw and dorsal pitch, indirectly preventing roll by precluding most pitch and yaw combinations where roll could occur and potentially allowing greater forces to be applied across the vertebral column than would be possible with only soft-tissue constraints.

Positive FABER distance test is associated with higher alpha angle in symptomatic patients

PURPOSE

The purpose of this study was to determine the diagnostic value of the flexion abduction external rotation (FABER) distance test (FDT) for the diagnosis of cam-type femoroacetabular impingement (FAI) as defined by alpha angle.

METHODS

For this study, 603 patients with symptomatic, unilateral femoroacetabular impingement were included. Patients with symptoms of hip instability, bilateral symptoms, bilateral surgery, or bilateral alpha angles over 55 were excluded from the analysis. A positive FDT was defined as a difference of 4 cm or more between hips. A pathological cam was defined as an alpha angle of 78° or greater.

RESULTS

The average age was 36.4 ± 12 years, with 344 males and 259 females. Faber distance of the injured hip was correlated with age at surgery (rho = 0.148; p < 0.001). Alpha angle on the injured hip was positively correlated with injured hip FABER distance (rho = 0.276; p < 0.001). The average alpha angle in patients with a positive FABER distance test was 74° (SD = 11°) compared to 68° (SD = 8°) in patients with a negative distance test (p = 0.001). The sensitivity of the FDT to diagnose pathological cam was 0.848 (0.79-0.89) with a negative predictive value of 86% (81-90%).

CONCLUSION

This study demonstrated that the FABER distance test is correlated with the alpha angle and is a good diagnostic exam for pathological cam-type FAI as defined by and alpha angle equal to or greater than 78°.

CLINICAL RELEVANCE

FABER distance test is a simple test that can be used as a screening test to decide if FAI should be suspected and further testing is needed.

LEVEL OF EVIDENCE

III.

Microinstability of the hip: a previously unrecognized pathology

BACKGROUND

Hip microinstability is an established diagnosis; however, its occurrence is still debated by many physicians. Diagnosis of hip microinstability is often challenging, due to a lack of specific signs or symptoms, and patients may remain undiagnosed for long periods. This may lead to early manifestation of degenerative joint disease. Consequently, careful patient and family history must be obtained and diagnostic imaging should follow. After a thorough clinical evaluation of the patient with suspected hip microinstability, the physician should focus on how to improve symptoms and functionality in daily and sports activities.

PURPOSE

The purpose of this review article was to give a current update regarding this diagnosis and to provide a complete diagnostic approach in order to effectively treat hip microinstability.

METHODS

We reviewed the literature on the diagnosis, the non-operative and operative indications for the treatment of this complex and often misdiagnosed pathology.

CONCLUSION

Conservative treatment is considered the best initial approach, though, surgical intervention should be considered if symptoms persist or other hip pathology exists. Successful surgical intervention, such as hip arthroscopy, should focus on restoring the normal anatomy of the hip joint in order to regain its functionality. The role of the hip joint capsule has gained particular research interest during the last years, and its repair or reconstruction during hip arthroscopy is considered necessary in order to avoid iatrogenic hip microinstability. Various capsular closure/plication techniques have been developed towards this direction with encouraging results.

LEVEL OF EVIDENCE

V.

Evaluation of hip pain in young adults

Hip pain is a common complaint in the young, athletic patient population. Primary, intra-articular sources of hip pain are becoming increasingly recognized by primary care providers and sports medicine specialists. Prior to deciding among the various treatment options for the many sources of hip pain in the athletic patient population, the clinician must be able to recognize and accurately diagnose the underlying pathology. Advances in imaging modalities and our understanding of the pathophysiology have improved our ability to accurately understand and diagnose the source of hip pain in this patient population. This review presents a comprehensive strategy for the workup and diagnosis of young, athletic patients presenting with hip pain, and provides the sports medicine specialist with the tools to correlate the patient's history, physical examination, and imaging findings and to treat these challenging patients.

Clinical and radiographic diagnosis of femoroacetabular impingement

Femoroacetabular impingement (FAI) in the adolescent patient is becoming increasingly recognized. A number of morphologic variants can lead to abnormal abutment of the femoral neck against the acetabular rim. Unrecognized FAI can lead to the development of secondary hip disorders including osteoarthritis. FAI is both a clinical and radiographic diagnosis and requires a thorough and complete understanding to diagnose appropriately. A precise history and comprehensive physical examination is paramount. Radiographs and advanced imaging techniques help to confirm the diagnosis.

History and physical examination of the hip: the basics

The history and physical examination of the hip is the key component for evaluation of patients presenting with hip pain. As our understanding of the anatomy and biomechanics of the normal hip vs the pathologic hip advances, the physical examination progresses as well. As with the shoulder and knee examinations, there are critical steps that form the basis of the examination of the hip joint. This hip examination contains 21 steps, which compares well with the shoulder 20 step exam and the knee 33 step exam. Consideration should be given for the hip as comprised of 4 layers: the osseous, capsulolabral, musculotendinous, and neurovascular. The hip represents the link between the upper body and lower body, therefore the fifth layer, the kinematic chain, plays an essential role in treatment recommendations. A clinical evaluation of the hip that incorporates this multifactor thought process will lead to an accurate diagnosis in a timely manner. This paper is a description of the 21 core examinations of a standardized clinical evaluation of the hip.

Hip internal rotation is correlated to radiographic findings of cam femoroacetabular impingement in collegiate football players

PURPOSE

The objective of this study was to determine whether physical examinations (flexion-abduction-external rotation [FABER], impingement, range-of-motion profiles) could be used to detect the bony abnormalities of femoroacetabular impingement (FAI) in an athletic population.

METHODS

We performed a prospective study of 65 male collegiate football players. Both hips were evaluated by 2 orthopaedic surgeons for radiographic signs of FAI. The alpha angle and head-neck offset were measured on frog-leg lateral films. The center-edge angle, acetabular index, crossover sign, and alpha angle were measured on anteroposterior films. Measurements were averaged for both observers. Maximum hip range of motion in flexion (supine) and internal/external rotation (supine, sitting, and prone) was measured with a goniometer. Pain provoked by the impingement and FABER tests was also recorded. Examinations were completed at 2 of 4 stations (2 duplicates), each staffed by 2 clinicians (1 examined and 1 measured). The relation between each range-of-motion and radiographic measure was determined. Data from each station were assessed separately. Only those regressions significant (P < .05) for paired stations were considered clinically significant.

RESULTS

The alpha angle and head-neck offset measured on the frog-leg lateral films were significantly correlated (all P < .01) to supine, sitting, and prone internal rotation for all stations. Correlation coefficients ranged from -0.59 to -0.35 for alpha angle and 0.42 to 0.57 for head-neck offset. Although 95% of the hips had at least 1 radiographic sign of FAI, pain was reported in only 8.5% and 2.3% during the impingement and FABER tests, respectively.

CONCLUSIONS

Internal rotation correlates to radiographic measures of cam FAI in this cohort of collegiate football players. Football players with diminished internal rotation in whom hip pain develops should be evaluated for underlying cam FAI abnormalities.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

An algorithmic approach to mechanical hip pain

BACKGROUND

As our understanding of hip pathology evolves, the focus is shifting toward earlier identification of hip pathology. Therefore, it is vitally important to elucidate intra-articular versus extra-articular pathology of hip pain in every step of the patient encounter: history, physical examination, and imaging.

QUESTIONS/PURPOSES

The objective was to address the following research questions: (1) Can an algorithmic approach to physical examination of a painful non-arthritic hip provide a more accurate diagnosis and improved treatment plan? (2) Does an anatomical layered concept of clinical diagnosis improve diagnostic accuracy? (3) What are the diagnostic tools necessary for the accurate application of a four-layer (osteochondral, inert, contractile, and neuromechanical) diagnosis?

METHODS

An unrestricted computerized search of MEDLINE was conducted. Different terms were used in various combinations.

RESULTS

An algorithmic approach to physical examination of a painful nonarthritic hip, including history, physical examination (specific tests), and advanced imaging allow for better interpretation of debilitating intra- and extra-articular disorders and their effect on core performance. Additionally, it improves our understanding as to how underlying abnormal joint mechanics may predispose the hip joint and the associated hemipelvis to asymmetric loads. These abnormal joint kinematics (layer I) can lead to cartilage and labral injury (layer II), as well as resultant injury to the musculotendinous (layer III) and neural structures (layer IV) about the hip joint and the hemipelvis. The layer concept is a systematic means of determining which structures about the hip are the source of hip pathology and how to best implement treatment.

CONCLUSIONS

A clear understanding of the differential diagnosis of hip pain through a detailed and systematic physical examination, diagnostic imaging assessment, and the interpretation of how mechanical factors can result in such a wide range of compensatory injury patterns about the hip can facilitate the diagnosis and treatment recommendations.

Lateral hip pain in an athletic population: differential diagnosis and treatment options

CONTEXT

Historically, the term greater trochanteric pain syndrome has been used to describe a spectrum of conditions that cause lateral-sided hip pain, including greater trochanteric bursitis, snapping iliotibial band, and/or strains or tendinopathy of the abductor mechanism. Diagnosis of these conditions may be difficult because clinical presentations are variable and sometimes inconclusive. Especially difficult is differentiating intrinsic pain from pain referred to the greater trochanteric region. The purposes of this article are to review the relevant anatomy and pathophysiology of the lateral hip.

EVIDENCE ACQUISITION

Data were collected through a thorough review of the literature conducted through a MEDLINE search of all relevant papers between 1980 and January 2010.

RESULTS

Recent advances in imaging and an improved understanding of pathomechanics have helped to guide the evaluation, diagnosis, and appropriate treatment for patients presenting with lateral hip pain.

CONCLUSION

Various diagnostic tools and treatment modalities can be used to effectively manage the athletic patient presenting with lateral hip pain.

Hip instability

Understanding of the etiology and pathology of hip instability has increased in recent years as new information has emerged regarding the disease processes of the hip. Hip instability, heretofore considered uncommon in clinical practice, is increasingly recognized as a pathologic entity. Instability may be classified as traumatic or atraumatic, and diagnosis is made based on patient history, physical examination, and imaging studies. Plain radiography, MRI, MRI arthrography, and hip instability tests (eg, posterior impingement, dial) can be used to confirm the presence of instability. Nonsurgical management options include physical therapy and protected weight bearing. Surgical intervention, whether arthroscopic or open, is required for large acetabular fractures and refractory instability. Knowledge of the etiology and evolving research of hip instability is essential to understand the spectrum of hip disease.

Evaluation of the hip

The evaluation of the hip has evolved over generations of orthopedic surgeons. A number of diagnostic tests have been described for specific pathologies that include a common base of maneuvers. A consistent hip examination is conducted to screen the hip, back, abdominal, neurovafscular, and neurologic systems and to find any comorbidities that often exist with complex hip pathology. Provided is a comprehensive evaluation of the hip with proposed descriptions of traditional tests along with provocative maneuvers. Through the use of a common set of diagnostic procedures and terminology, there will be improvement in the accuracy of diagnostic exams for determining hip pathology.

Peri-epiphyseal and Overuse Injuries in Adolescent Athletes

CONTEXT

Overuse injuries of the musculoskeletal system in immature athletes are commonly seen in medical practice.

EVIDENCE ACQUISITION

An analysis of published clinical, outcome, and biomechanical studies of adolescent epiphyseal and overuse injuries was performed through 2008 to increase recognition and provide treatment recommendations.

RESULTS

Adolescent athletes can sustain physeal and bony stress injuries. Recovery and return to play occur more swiftly if such injuries are diagnosed early and immobilized until the patient is pain-free, typically about 4 weeks for apophyseal and epiphyseal overuse injuries. Certain epiphyseal injuries have prolonged symptoms with delayed treatment, including those involving the bones in the hand, elbow, and foot. If such injuries are missed, prolonged healing and significant restrictions in athletic pursuits may occur.

CONCLUSION

Some of these injuries are common to all weightbearing sports and are therefore widely recognized. Several are common in gymnastics but are rarely seen in other athletes. Early recognition and treatment of these conditions lead to quicker recovery and so may prevent season-ending, even career-ending, events from occurring.

Acetabular labral tears of the hip: examination and diagnostic challenges

The purpose of this clinical commentary is to provide an evidence-based review of the examination process and diagnostic challenges associated with acetabular labral tears of the hip. Once considered an uncommon entity, labral tears have recently received wider recognition as a source of symptoms and functional limitation. Information regarding acetabular labral tears and their association to capsular laxity, femoral acetabular impingement (FAI), dysplasia of the acetabulum, and chondral lesions is emerging. Physical therapists should understand the anatomical structures of the hip and recognize how the clinical presentation of labral tears is difficult to view isolated from other hip articular pathologies. Clinical examination should consider lumbopelvic and extra-articular pathologies in addition to intra-articular pathologies when assessing for the source of symptoms and functional limitation. If a labral tear is suspected, further diagnostic testing may be indicated. Although up-and-coming evidence suggests that information obtained from patient history and clinical examination can be useful, continued research is warranted to determine the diagnostic accuracy of our examination techniques.

Clinical Examination of the Athletic Hip

This article provides a succinct and complete method for the clinical evaluation of the hip. Included are descriptions of examination tests as well as their relationships to possible pathology of the hip. The examination is divided into five stages: seated, standing, supine, lateral, and prone; with a total of 11 assessment points. The method for evaluation outlined will assist physicians in determining the location and etiology of presenting hip pathologies. As with any examination, practice and repetition are essential to gain an appreciation of what constitutes a normal as well as an abnormal examination.

Neuromuscular Hip Biomechanics and Pathology in the Athlete

Although hip arthroscopic techniques have been developed and evolved over the last 5 to 10 years to help active athletes, the mechanisms of athletic hip injuries across various sports are not well understood. The purpose of this article is to review the literature related to the osseous and ligamentous support as well as the neuromuscular control strategies associated with hip joint mechanics. The neuromuscular contributions to hip stability and mobility with respect to gait will be provided because this data represents the largest body of knowledge regarding hip function. Further, this article will present and describe probable mechanisms of injury in sporting activities most often associated with hip injury in the young athlete.

Acetabular labral tears with underlying chondromalacia: a possible association with high-level running

PURPOSE

The use of hip arthroscopy has helped delineate intra-articular pathology and has enabled clinicians to further elucidate the factors responsible for injuries, such as running. The subtle development of degenerative changes may be a result of repetitive impact loading associated with this sport. This study presents a population of runners with common pathologic acetabular changes.

TYPE OF STUDY

Case series.

METHODS

Eight high-level runners with an average age of 36 years (range, 19 to 45 years) were seen for complaints of increasing hip pain with running without any history of macrotrauma. All of the patients had either run several marathons (4), were triathletes (1), Olympic middle distance runners (1), or had run more than 10 miles per week for longer than 5 years (2). Plain radiographic analysis revealed no degenerative changes and an average center-edge (CE) angle of 36.7 degrees (range, 28 degrees to 44 degrees).

RESULTS

All patients underwent hip arthroscopy with labral debridement. In 6 patients (75%), a chondral injury of the acetabular cartilage underlying the labral tear was noted. In addition, 3 patients had ligamentum teres disruptions.

CONCLUSIONS

It is possible that the development of these tears is the result of subtle instability, which may be exacerbated by running, eventually leading to labral tearing and possible ligamentum teres disruption. While perhaps concurrently, subtle acetabular dysplasia may play a role. Although this study does not confirm an association between running and the development of labral tears or chondral lesions in the hip, it certainly questions whether there is an injury pattern common to this population, a "runner's hip."

LEVEL OF EVIDENCE

Level IV.

An Overview of Hip Injuries in Running

Running has steadily gained in worldwide popularity and is the primary exercise modality for many individuals of all ages. Its low cost, versatility, convenience and related health benefits appeal to men and women of broad cultural, ethnic and economic backgrounds. With more children and adults participating in recreational and competitive running, the incidence of injuries has steadily increased. Most running-related injuries affecting the lower extremities are due to preventable training errors, and some may necessitate medical evaluation or a significant reduction in training. Hip injuries in runners are due to interactions of intrinsic and extrinsic factors that adversely affect the complex regional anatomy. Acute or chronic hip pain presents a diagnostic and therapeutic challenge because the vague, nonspecific symptoms and signs may originate from local, regional or distant foci. Muscle strains and tendonitis are the most common aetiologies of hip pain and typically result from sudden acceleration/deceleration manoeuvres, direction changes or eccentric contractions. Apophysitis and avulsion fractures may affect younger runners and produce localised pain at muscle attachment sites. Iliotibial band syndrome is a common cause of lateral hip and knee symptoms characterised by sharp or burning pain that is exacerbated by activity. Bursitis, due to repetitive activity or acute trauma, may affect the trochanteric, ischial or iliopectineal bursae. Hip osteoarthritis may also produce persistent pain that worsens with running. Stress fractures are potentially serious conditions that affect women more frequently than men. Snapping hip syndrome is a benign condition that results from tight connective tissues' passing repeatedly over the greater trochanter, anterior hip capsule, lesser trochanter, femoral head or iliopectineal eminence. Acetabular labral tears, sports hernias and nerve entrapment syndromes are also potential causes of persistent hip pain in runners. Treatment of hip pain in running should focus not only on addressing the symptoms but also identifying the underlying conditions that precipitated the injury. Injury prevention and comprehensive rehabilitation are essential, since prior hip injuries increase the risk of subsequent ones. Coaches, trainers and medical personal who care for runners should advocate running regimens, surfaces, shoes, technique and individualised conditioning programmes that minimise the risk of initial or recurrent hip injuries.

Chondral degeneration and therapeutic hip arthroscopy

Therapeutic hip arthroscopy for the treatment of chondral degeneration remains controversial. A retrospective cohort study examined 70 patients of mean age 47 (range 22-87) years who had undergone hip arthroscopy and assessed them for evidence of chondral degeneration using radiological and arthroscopic means. Clinical outcome was assessed using a modified Farjo and Glick classification. Thirty-nine patients had evidence of chondral degeneration on arthroscopy with or without radiological diagnosis, and 31 had alternative pathology. If patients were found to have chondral degeneration at arthroscopy, they were significantly more likely to have a poor clinical result than if an alternative diagnosis such as a loose body or labral tear was made (p<0.0001). Patients with evidence of degenerative changes on plain hip radiographs were significantly more likely to have a poor clinical result following hip arthroscopy than patients with unremarkable hip radiographs (p<0.0001). Therapeutic hip arthroscopy for osteoarthritis should be used with caution, as a poor clinical result is significantly more likely compared to other pathologies such as a labral tear or loose body.

The young adult with hip pain: diagnosis and medical treatment, circa 2004

Hip pain in young adults (18-35 years old) often is characterized by nonspecific symptoms, normal imaging studies, and vague findings from the history and physical examination. In younger patients, pain is more likely to be caused by congenital hip dysplasia, athletic injuries, trauma, spondyloarthropathy, and by conditions that first appear during this stage of life, such as rheumatoid arthritis, osteoarthritis, intravenous drug use, alcoholism, or corticosteroid use. The history and physical examination may narrow the diagnosis to intraarticular, extraarticular, or referred sources of pain. Plain radiography and magnetic resonance imaging are the preferred initial imaging procedures. Analyses of the blood, urine, and synovial fluid can be helpful in diagnosing inflammation, infection, and systematic rheumatic disease. Fractures, infection, and ischemic necrosis should be ruled out early because they require immediate treatment to prevent damage to the joint. Hip trauma at a young age increases the risk of osteoarthritis with advancing age, and, unlike most older adults, young adults receiving total hip replacement can expect revision surgery. Medical treatment often involves patient education, physical therapy, and pharmacotherapy. Acetaminophen, nonsteroidal anti-inflammatory drugs, and opioids for pain and antibiotics for infection are the most often prescribed drugs for this population.

Hip arthroscopy: current indications, treatment options, and management issues

The management of hip injuries in athletes has evolved significantly in the past few years with the advancement of arthroscopic techniques. The application of minimally invasive surgical techniques has facilitated relatively rapid returns to sporting activity in both recreational and elite athletes. Recent advancements in both hip arthroscopy and magnetic resonance imaging have elucidated several sources of intraarticular abnormalities that result in chronic and disabling hip symptoms. Many of these conditions were previously unrecognized and, thus, left untreated. Current indications for hip arthroscopy include the presence of symptomatic acetabular labral tears, hip capsule laxity and instability, chondral lesions, osteochondritis dissecans, ligamentum teres injuries, snapping hip syndrome, iliopsoas bursitis, and loose bodies (for example, synovial chondromatosis). Less common indications include management of osteonecrosis of the femoral head, bony impingment, synovial abnormalities, crystalline hip arthropathy (gout and pseudogout), infection, and posttraumatic intraarticular debris. In rare cases, hip arthroscopy can be used to temporize the symptoms of mild-to-moderate hip osteoarthritis with associated mechanical symptoms. This article discusses the current clinical and radiographic methods to detect early hip joint disease and the current indications and surgical techniques of hip arthroscopy.

Acute athletic trauma to the hip and pelvis

Athletic trauma to the hip and pelvis is rare; however, as football players hit harder and skiers ski faster, the incidence of high-energy hip and pelvis trauma can be expected to increase. As the energy of the injury increases, so do the associated risks. Therefore, a thorough understanding of on-field recognition and management is a necessary addition to the armamentarium of the sports medicine physician.