Tönnis stage 0 and 1 acetabular rim cartilage injuries: Incidence, grade, location and associated pre-surgical factors

Abstract Introduction and purpose Articular cartilage lesions have a direct effect on the success of surgical treatment. The aim of this study was to determine the prevalence rate, location, grade, and factors associated with acetabular rim articular cartilage lesions in patients undergoing hip arthroscopy. Material and methods A prospective study was conducted by analysing the intraoperative data of 152 hips in 122 patients treated with hip arthroscopy for femoroacetabular impingement from January 2011 to May 2016. The prevalence rate, location, and grade were calculated, as well as the pre-operative factors associated with acetabular rim articular cartilage lesions. Results The mean age of the patients was 38.6 years. The Tonnis grade was 0 in 103 hips, and 1 in 52 hips. Acetabular rim articular cartilage lesions were present in 109 (70.3%) hips. The location of the lesions was superior-anterior. Independent risk factors for the presence of acetabular rim articular cartilage lesions were an alpha-angle equal or greater than 55°, duration of symptoms equal or greater than 20 months, and Tegner activity scale level equal or greater than 6. Discussion Although patients were classified as Tonnis grade 0 and 1, and 3 T MRI reported acetabular lesions in 1.3% of cases, there was a high frequency of acetabular rim cartilage lesions. Knowledge of the independent risk factors associated with acetabular rim articular cartilage lesions may assist the orthopaedic surgeon with the decision to perform hip arthroscopy.