FP5.6 Arthroscopic Core Decompression Compared to Standard Open Technique for Femoral Head Osteonecrosis: Short-Medium Term Outcomes

Introduction: Untreated femoral head osteonecrosis (FHO) leads to devastating hip joint degeneration. In this study, treatment of early FHO with core decompression surgery was compared between arthroscopic and standard open techniques. Perioperative outcomes, conversion to total hip arthroplasty (THA), and functional improvement were assessed.

Method: A retrospective analysis was conducted on patients with Ficat Arlet Stage 1 or 2 FHO who underwent arthroscopic and standard open core decompression between 2015 and 2020. Inclusion criteria were having preoperative imaging available (including pelvic AP, hip lateral direct X-ray imaging and hip MR imaging) and having at least three years of follow-up. Patients with advanced FHO, trauma-related avascular necrosis, hip dysplasia, or prior hip surgery were excluded. Arthroscopic core decompression was performed on twenty-four patients, while twenty-five patients underwent the standard open technique. The minimum follow-up was 3 years. Demographics, radiological measurements, functional improvement in terms of Harris Hip Scores (HHS), complications, and THA rates were compared.

Results: A significantly lower number of THA conversions were observed in the arthroscopic group (5, 20% vs 0, 0%, p=0.02). Baseline characteristics including age, gender, body mass index, follow-up periods, side, LCEA and preoperative symptom durations were similar between groups. Ficat Arlet Stages and preoperative HHS were also similar. Additional pathologies (femoroacetabular impingement, labral tear, synovitis) as diagnosed with preoperative imaging were similar (arthroscopic, 50% vs standard 48%, p=0.89). During arthroscopy, additional procedures (e.g., pincer excision, labral repair) were performed on twenty patients, there were no additional interventions in the standard group. Significant postoperative improvement in HHS was demonstrated in both groups, with higher scores achieved in the arthroscopic group (92.8 vs. 85.4, p<0.001). No major complications were encountered. Minor complications were similar (25% vs. 24%, p=0.93), although temporary pudendal nerve neuropraxia was more frequent with arthroscopy (16.7% vs. 0%, p=0.05).

Conclusion: Arthroscopic core decompression for early FHO may offer advantages over the standard technique. Our study found lower THA conversion rates and improved postoperative function (HHS scores) with arthroscopy. Arthroscopy facilitates treatment of additional pathologies within the joint which may be diagnosed with preoperative MRI or detected intraoperatively. Patients should be informed regarding the potential for temporary pudendal nerve neuropraxia following arthroscopy.

Statistical Analysis: Continuous variables were compared with independent t-test for normally distributed quantitative data and Wilcoxon rank-sum test for non-normally distributed quantitative data. Fisher’s Exact Test for observations with expected frequencies of less than 5. A P value of <0.05 was considered significant.