Eighty Percent of Patients With Surgical Hip Dislocation for Femoroacetabular Impingement Have a Good Clinical Result Without Osteoarthritis Progression at 10 Years

Abstract

Background We previously reported the 5-year followup of hips with femoroacetabular impingement (FAI) that underwent surgical hip dislocation with trimming of the head-neck junction and/or acetabulum including reattachment of the labrum. The goal of this study was to report a concise followup of these patients at a minimum 10 years. Questions/purposes We asked if these patients had (1) improved hip pain and function; we then determined (2) the 10-year survival rate and (3) calculated factors predicting failure. Methods Between July 2001 and March 2003, we performed surgical hip dislocation and femoral neck osteoplasty and/or acetabular rim trimming with labral reattachment in 75 patients (97 hips). Of those, 72 patients (93 hips [96%]) were available for followup at a minimum of 10 years (mean, 11 years; range, 10-13 years). We used the anterior impingement test to assess pain and the Merle d'Aubigné-Postel score to assess function. Survivorship calculation was performed using the method of Kaplan and Meier and any of the following factors as a definition of failure: conversion to total hip arthroplasty (THA), radiographic evidence of worsening osteoarthritis (OA), or a Merle d'Aubigné-Postel score less than 15. Predictive factors for any of these failures were calculated using the Cox regression analysis. Results At 10-year followup, the prevalence of a positive impingement test decreased from preoperative 95% to 38% (p \ 0.001) and the Merle d'Aubigné-Postel score increased from preoperative 15.3 ± 1.4 (range, 9-17) to 16.9 ± 1.3 (12-18; p \ 0.001). Survivorship of these procedures for any of the defined failures was 80% (95% confidence interval, 72%-88%). The strongest predictors of failure were age [ 40 years (hazard ratio with 95% confidence interval, 5.9 [4.8-7.1], p = 0.002), body mass index [ 30 kg/m 2 (5.5 [3.9-7.2], p = 0.041), a lateral center-edge angle \ 22°o r [ 32°(5.4 [4.2-6.6], p = 0.006), and a posterior acetabular coverage \ 34% (4.8 [3.7-5.6], p = 0.006). Conclusions At 10-year followup, 80% of patients with FAI treated with surgical hip dislocation, osteoplasty, and labral reattachment had not progressed to THA, developed worsening OA, or had a Merle d'Aubigné-Postel score of less than 15. Radiographic predictors for failure were related to over-and undertreatment of acetabular rim trimming. Level of Evidence Level IV, therapeutic study.

Periacetabular Osteotomy Provides Higher Survivorship Than Rim Trimming for Acetabular Retroversion

“…It can be treated by anteverting PAO (Fig. 5A-C) [31,40,41,48] or acetabular rim trimming [2,7,13,29,42] with refixation of the labrum (Fig. 6A-C).…”

“…Reports of isolated open or arthroscopic acetabular rim trimming for acetabular retroversion are not available with a followup of 10 years. Most of the reports have a followup of \ 5 years [4,19,33] or report on ''pincer''-type hips without further specification [1,29,42]. There is only one study comparing the surgical treatments for acetabular retroversion.…”

“…We performed a power analysis for the primary research question regarding survivorship at 10 years followup with a two-sided level of significance of 5%, beta error of 5%, known long-term survivorship of hips undergoing anteverting PAO for acetabular retroversion of 71% with a SD of 17% [39], and known long-term survivorship of hips undergoing surgical hip dislocation of 80% for femoroacetabular impingement (FAI) with a SD of 5% [42] resulting in a minimal sample size of at least 35 hips per group.…”

Is Increased Acetabular Cartilage or Fossa Size Associated With Pincer Femoroacetabular Impingement?

“…We know from mechanical and modeling studies of dysplastic hips that the higher peak contact forces and stresses on articular cartilage from a smaller contact area contribute to early joint degeneration [12,[18][19][20]31]. Iatrogenic creation of a smaller articular surface with excessive acetabular rim trimming during surgical dislocation procedures is associated with poorer clinical and radiographic outcomes at both 5-and 10-year followup [25,26]. Femoral head undercoverage from excessive rim trimming leads to more rapid joint deterioration than inadequately treated pincer impingement [25].…”

“…Iatrogenic creation of a smaller articular surface with excessive acetabular rim trimming during surgical dislocation procedures is associated with poorer clinical and radiographic outcomes at both 5-and 10-year followup [25,26]. Femoral head undercoverage from excessive rim trimming leads to more rapid joint deterioration than inadequately treated pincer impingement [25]. Thus, acetabular rim trimming in deep subtype 2 hips risks decreasing the acetabular articular surface to a precarious threshold that would elevate the joint contact forces and stresses to an unfavorable level.…”