ePoster #715 - ISHA Annual Scientific Meeting 2016

Factors Increasing Risk Of Failure Following Hip Arthroscopy – A Case Control Study

Owain Lloyd Ioan Davies, MA, MBBChir, MRCS, Bangor UNITED KINGDOM
George Grammatopoulos, DPhil, FRCS (Tr&Orth), Reading UNITED KINGDOM
Thomas C.B. Pollard, MD, FRCS (Tr & Orth), Reading UNITED KINGDOM
Antonio (Tony) Andrade, MB BS, FRCS (Tr & Orth), Reading, Berkshire UNITED KINGDOM

Royal Berkshire Hospital NHS Foundation Trust, Reading, Berkshire, UNITED KINGDOM

FDA Status Not Applicable

Summary: Case control study to identify radiological and intra-operative findings associated with increased risk arthroplasty following hip arthroscopy.

Hip arthroscopy may provide the opportunity to treat early osteoarthritis and prevent progression to end-stage disease, but currently up to 35% of patients undergoing hip arthroscopy are converted to arthroplasty within 10-yrs. Understanding which factors predict failure will improve surgical decision-making and consequently the outcome of arthroscopy. The aim of this study was to identify radiological and intra-operative findings associated with increased risk of arthroplasty following hip arthroscopy.

A retrospective case control study from a single UK centre analysing a database of 377 hip arthroscopies performed between 2008 and 2013 was performed. 45 patients that had a hip arthroscopy and subsequently underwent hip arthroplasty (cases) were identified. Controls (n=66), obtained from the same database, were patients with preserved hips matched for age (p=0.6), gender (p=0.5), and follow-up (p=0.1). Clinical information, radiological investigations, operative findings (presence and extent of articular cartilage damage graded by the UCL system, and labral pathology) and procedure performed (labral repair, debridement, osteochondroplasty, microfracture etc.) were reviewed.

Morphological features were important in predicting failure. The cases had higher acetabular and extrusion indices, lower lateral centre-edge-angles, and higher alpha angles compared to controls (p<0.01).

Cases were more likely to have cartilage damage on pre-operative MRI scans (p=0.03), and were more likely to have irreparable labral tears, femoral head cartilage damage and extensive acetabular cartilage damage (p=0.02 respectively).

Patients with signs of dysplasia (acetabular index > 15°) had double the risk of failure (p = 0.008); if they also had cartilage damage on the pre-operative MRI, the risk ratio increased to 4 (p = 0.001). The presence of acetabular articular damage in more than 2 zones doubled the risk of failure (p<0.001). The lowest rate of failure occurred in hips without features of dysplasia and no signs of chondropathy.

Our study confirms that prognosis following hip arthroscopy may be predicted by analysis of joint morphology, evidence of osteoarthritis on preoperative imaging, and intraoperative findings. Consideration of these variables will enhance the success of arthroscopy as a joint-preserving surgical technique.