Clinical and imaging diagnosis of lesions of the labrum acetabulare.

Labral lesions are common findings in residual hip dysplasia, indicating biomechanical decompensation of the hip joint. MR-Arthrography has shown an excellent accuracy of over 90 % to detect these lesions. Nevertheless, so far clinical sings, radiological diagnosis and therapeutical consequences are not well known. In a prospective study, patients suspicious for labral lesions were evaluated using a standard clinical protocol, including history, clinical signs, radiography and MR-Arthrography. Clinical signs were tested by six criteria and two provocation tests. In 11 % patients clinical suspicious was wrong. Best agreement with MR-Arthrography was found for "knife sharp" groin pain (100 %), impingement test (100 %) and painful giving way (83 %). 35 % of patients showed minor (grade 2) and 52 % severe (grade 3 and 4) dysplasia. Independent from grade of dysplasia, no or only slight arthrosis (grade 0 and 1) was found in 64 % of patients. In 16 % a single acetabular cyst could be detected on radiographs, which all could be identified as intraosseous ganglia on MR-Arthrography. Labral lesions type A (post traumatic) were found in 23 % of the patients with only no or minor dysplasia (grade 1 and 2), whereas labral lesions type B (dysplastic) were found in 67 % of the patients with severe dysplasia (grade 3 and 4). Clinical signs for labral lesions are typical but can also be observed in other pathologies of the hip joint. Based on the findings of this study, we recommend radiographic evaluation for dysplasia and MR-Arthrography in patients with clinical suspicion for labral lesions of the hip joint.