Total Hip Arthroplasty or Arthroscopy for Pigmented Villonodular Synovitis of the Hip: A Retrospective Study with 3‐Year Follow‐Up at Minimum

OBJECTIVE: Pigment Villonodular synovitis of the hip, a rare pain proliferation of the synovium, was treated successfully with total hip arthroplasty and arthroscopy. Most recent results come from small case series with no study comparing arthroscopy and arthroplasty. In this study, we aimed to show and compare the clinical outcomes of arthroscopy and total hip arthroplasty (THA) in pigment Villonodular synovitis of the hip. METHODS: This was a retrospective clinical trial with data from patients with pigment Villonodular synovitis of the hip between 2010 and 2019. The study included 17 patients in the THA group, and 20 patients in the arthroscopy group. The clinical outcomes were evaluated at 3, 6, and 12 months, at 1 and 2 years, and every 5 years afterward. The clinical efficacy was measured using the Harris hip scores (HHSs) and visual analogue scale (VAS) score. RESULTS: The mean HHS improved from 45.24 ± 10.36 to 78.94 ± 19.11 in the THA group (t = −6.394, P = 0.000) and 45.30 ± 11.08 to 71.60 ± 19.78 (t = −5.187, P = 0.000) in the arthroscopy group from pre‐operation to the final follow‐up. There is no significant difference between the two groups (t = 1.051, P = 0.301). The mean VAS improved from 3.65 ± 0.79 to 0.35 ± 0.70 (t = 12.890, P = 0.000) in the THA group and 4.05 ± 0.94 to 1.35 ± 1.79 (t = 5.979, P = 0.001) in the arthroscopy group postoperatively. There is no significant difference between the two groups (t = 1.329, P = 0.193). Recurrence of PVNS was diagnosed in four patients (20%) of the arthroscopy group and they underwent THA after arthroscopy, and the mean interval was 44.25 ± 6.98 months. All patients reached level 5 muscle strength by the final follow‐up. All the patients' buckling ranges were over 105 degrees. Their internal and external hip rotation was over 15 degrees. Their hip adduction was over 20 degrees, and abduction over 30 degrees. CONCLUSION: Both THA and arthroscopy in the setting of PVNS can improve patients' function and lead to a low rate of local recurrence. By selecting patients well for each approach, one can expect a reasonable result.