GANZ PERI-ACETABULAR OSTEOTOMY FOR SYMPTOMATIC HIP DYSPLASIA: THE SCOTTISH EXPERIENCE TO DATE WITH MINIMUM ONE- YEAR FOLLOW-UP

Ganz peri-acetabular osteotomy is commonly used to treat symptomatic hip dysplasia. It aims to increase the load bearing contact area of the hip to reduce the risk of subsequent osteoarthritis. In this study we assess the radiographic and clinical results of the procedure since its introduction to our unit. All patients undergoing Ganz osteotomies at our unit were followed up prospectively. Data collected included patient demographics and pre- and post-operative functional scores (Harris and Non-arthritic hip scores). In addition, acetabular correction was evaluated on pre-and post-operative radiographs (using Centre-Edge angle and Tonnis angle). Complications were also noted. Overall 50 procedures were performed between 2007 and 2013 with median follow-up of 3 years (1–7 years). The majority of patients (90%) were female. Average age at time of surgery was 32 years (17–39). There were significant improvements in pre- and post-operative median functional scores (Modified Harris Hip Score = 52 versus 63, p=0.001), Non-arthritic Hip Score = 49 versus 60, p=0.01). Median Centre Edge Angle improved from 15 degrees pre-operatively (range = 8–19 degrees) to 29 degrees post-operatively (22–36 degrees), p=0.02. Similarly, pre-operative Tonnis angle improved from 19 degrees (16–38) to 7 degrees (2–14), p=0.01. Four patients developed post-operative complications: 1 superficial wound infection, 1deep infection requiring hip washout and antibiotic treatment and 2 patients subsequently requiring total hip replacements. We have shown that the Ganz peri-acetabular osteotomy can be effective for the treatment of painful hip dysplasia improving both functional and radiographic outcomes. However, patient selection is a key factor.