M. Rebecca Leibold, MPT, MTC1, Peter A. Huijbregts, PT, DPT, OCS, FAAOMPT, FCAMT2,
Richard Jensen, PT, PhD3
Abstract: Hip injuries are prevalent, especially within the athletic population. Of the hip injuries in this population, some 18–55% are lesions to the labrum of the hip. Clinical diagnosis of hip labral lesions is difficult because data on prevalence are varied. In addition, data on the prevalence of internal and external risk factors are absent as are data on the correlation of these risk factors with labral lesions, making it difficult to gauge the diagnostic utility. The mechanism of injury is often unknown or not specific to labral lesions. Internal risk factors may remain hidden to physical therapists because in most jurisdictions, ordering imaging tests is not within their scope of practice. Anterior inguinal pain seems highly sensitive for the diagnosis of patients with labral lesions but can hardly be considered specific; data on other pain-related and mechanical symptoms clearly have little diagnostic utility, making these data collected during the patient history almost irrelevant to diagnosis. By way of a comprehensive literature review and narrative and systematic analysis of the methodological quality of the retrieved diagnostic utility studies, this paper aimed to determine a diagnostic physical examination test or test cluster based on current best evidence for the diagnosis of hip labral lesions. Current best evidence indicates that a negative finding for the flexion-adduction-internal rotation test, the flexion-internal rotation test, the impingement provocation test, the flexion-adduction-axial compression test, the Fitzgerald test, or a combination of these tests provides the clinician with the greatest evidence-based confidence that a hip labral lesion is absent. Currently, research has produced no tests with sufficient specificity to help confidently rule in a diagnosis of hip labral lesion. Suggestions for future research are provided.
Key Words: Concurrent Criterion-Related Validity, Hip Labral Lesion, Physical Examination, STARD, Systematic Review.
Hip injuries comprise 5–9% of all injuries sustained by high school athletes1. Hip and groin pain are common reasons for people to seek physical therapy treatment. However, differential diagnosis for these symptoms is complex (Table 1). Injuries to the labrum of the hip constitute one of the possible reasons for hip and groin pain. Narvani et al2 reported that 22% of athletes with groin pain were diagnosed with a labral tear. McCarthy et al3 found that 55% of their patients with mechanical hip pain had a labral tear. Without premortem information available allowing for correlation with symptom status, these same authors also harvested 54 cadaveric acetabula and found that 52% of these had labral lesions3. Santori and Villar4 reported on 412 arthroscopic surgeries for disabling hip pain of >6 months duration: 76 patients (18%) had acetabular labral tears. With the advent of arthroscopic surgery as an accurate means of diagnosis, hip labral injuries have become of growing interest to the medical profession.
However, clinical diagnosis of patients with hip labral lesions is difficult. For one, demographics for patients with labral injuries are highly variable: Ages reported in the literature ranged from 8 to
72, although most patients were in the fourth decade of life2,4-22. Labral lesions may be more common in women. When we combined all studies reviewed in this paper, 60% of patients were women. A higher activity level as found in runners, professional athletes, and those attending the gym 3 times a week has been suggested as a risk factor2,11. In addition, the majority of patients with labral pathology do not recall the mechanism of injury that led to their symptoms. Santori and Villar4 collected data on etiology from 58 of their 76 patients with acetabular labral tears: 29.3% were of unknown etiology, traumatic injury occurred in 25.9%, and in 44.8% the labral lesions were likely degenerative in nature. When patients do recall the mechanism of injury, this may include hyperabduction, twisting, falling, or running, or it may be related to a motor vehicle accident, sports, work, or a direct blow. Other external risk factors noted in the literature include repetitive microtrauma; sports activities that require frequent hip external rotation such as soccer, golf, hockey, karate, and ballet; running; hyperextension with or without external rotation; and dislocation23,24.
There are also internal risk factors; anatomical variations associated with labral lesions are mentioned in the literature (Table 2). Wenger et al25 noted structural abnormalities in 31 patients with labral tears including acetabular retroversion, coxa valga, abnormal Tonnis26 angle, small femoral head-neck offset, and incongruent hips. Peelle et al27 compared radiographs of 78 patients with labral tears confirmed on arthroscopy to those of 22 subjects without hip dysfunction. Of the patients with labral tears, 49% had an osseous abnormality including a lateral center-edge angle <25o, head-neck offset <9 mm, offset ratio <0.17, acetabular retroversion, femoral anteversion, an aspherical femoral head, and a Tonnis osteoarthritis grade (Table 326) of 1 and 2. Patients with labral tears demonstrated significantly smaller lateral center-edge angles (P=0.008), larger Tonnis angles (P=0.02), and a greater probability of acetabular dysplasia (P=0.001) than controls27. Ito et al28 compared 24 patients to 24 control subjects and found that patients had significantly less femoral anteversion (P<0.001); they also noted a significant between-group difference for head-neck offset (P<0.002). Siebenrock et al29 also found patients to have a significantly different head-neck offset when compared to a control group (P=0.01–0.04). Kassarjian et al14 studied 42 hips with an antero-superior labral tear: 93% had an abnormal head-neck offset with a mean angle of 69.7o; abnormal was defined as >55o. Acetabular retroversion, femoral anteversion, and abnormal head-neck offset all increase the chance of labral impingement against the acetabular rim, especially with active hip flexion with or without internal rotation. Two different joint morphologies have been proposed as a cause for femoro-acetabular impingement that may lead to labral failure30. A larger femoral head may lead to “cam” impingement whereby the head prematurely impacts the antero-superior aspect of the acetabular rim during active hip motions causing acetabular cartilage and labral damage. “Pincer” impingement occurs when a normal femoral head is paired with an abnormal acetabulum (e.g., coxa profunda or acetabular retroversion). This type initially affects only the labrum. Further internal risk factors mentioned in the literature include pelvic instability and degeneration, Legg-Calve Perthes disease, slipped capital femoral epiphysis, and a shallow tapering between the femoral head and neck; one study also reported osteonecrosis as a risk factor7,31,32.
The most common symptom in patients with labral pathology is anterior inguinal pain, whereas anterior thigh pain, lateral thigh pain, and buttock pain are less prevalent. Burnett et al7 found that 92% of their patients with labral tears complained of anterior groin pain. Keeney et al15 reported 97 of 102 patients with groin pain and Fitzgerald10 also noted anterior groin pain in 48 patients with confirmed labral tears. Pain level has been recorded as moderate to severe and pain has limited the patient’s activities. Walking, climbing stairs, running, and twisting motions at the hip have been reported as aggravating factors. Two studies also noted that patients had pain at night. Ito et al28 found night pain in 14 of 25 patients and Burnett et al7 reported 71% of their patients had night pain.
Labral lesions may also cause mechanical symptoms. Burnett et al7 reported 89% of patients with labral tears also mentioned a history of a limp. Fitzgerald10 reported 5 of 55 patients had a limp and Keeney et al15 noted that 39 of 102 subjects mentioned a limp. Some but not all patients with labral pathology have reported clicking, catching, or locking of the hip with motion. McCarthy et al20 found that 67% of subjects complained of clicking or locking with hip motion. Of their subjects, 72% had labral tears. However, the authors did not state whether those with clicking indeed had a labral tear. Narvani et al2 re-ported that 4 of 4 patients with labral tears noted clicking, but that 2 patients without labral tears also mentioned clicking. Leunig et al19 reported that 6 of 23 patients with labral tears had locking symptoms. Keeney et al15 found locking or catching in >50% of their patients, and Farjo9 reported that 18 of 28 patients who were found to have labral tears upon arthroscopy had mechanical symptoms. Fitzgerald10 reported that 34 of 64 patients had a click associated with hip pain and were also positive for labral tears.
In summary, data on prevalence of hip labral lesions provided in the literature are highly variable and likely de-pend strongly on the population studied. Exact data on the prevalence of the internal and external risk factors noted are absent as are hard data for correlation with labral lesions, thereby making it difficult to gauge the diagnostic utility. The mechanism of injury is often unknown or not specific to labral lesions. Internal risk factors may remain hidden to physical therapists, because in most jurisdictions ordering imaging tests is not within the scope of practice. Anterior inguinal pain seems highly sensitive for the diagnosis of patients with labral lesions but can hardly be considered specific. Data on other pain-related and mechanical symptoms clearly have little diagnostic utility, making these data collected during the patient history almost irrelevant to diagnosis. However, inaccurate diagnosis may result in prolonged rehabilitation and associated cost. Clinical tests capable of ruling out labral lesions with sufficient diagnostic confidence would prevent unnecessary arthroscopic surgery that is currently required for accurate diagnosis. Physical therapists, especially in a direct access role, are uniquely positioned in the health care system to clinically rule in or rule out a diagnosis of hip labral lesions and to facilitate appropriate management but due to scope of practice legislation, they are limited to history and physical examination in the diagnostic process. Therefore, the goal of this paper is to determine a diagnostic physical examination test or test cluster based on current best evidence for the diagnosis of hip labral lesions.