Patients With Borderline Hip Dysplasia Achieve Clinically Significant Outcome After Arthroscopic Femoroacetabular Impingement Surgery: A Case-Control Study With Minimum 2-Year Follow-up

Abstract

Background: There is a growing trend for hip arthroscopists to treat patients with borderline hip dysplasia (BHD) for femoroacetabular impingement syndrome (FAIS) without addressing the acetabular coverage. However, the literature of outcomes and failure rates for these patients is conflicting. Purpose: (1) To identify whether patients with BHD achieved 2-year similar patient-reported outcome, minimal clinically important difference (MCID), and patient acceptable symptomatic state (PASS) when compared with patients without BHD and (2) to identify predictors for achieving the MCID and PASS among patients with BHD who are undergoing hip arthroscopy for FAIS. Study Design: Cohort study; Level of evidence, 3. Methods: Data from consecutive patients who underwent primary hip arthroscopy with routine capsular closure for the treatment of FAIS between January 2012 and January 2017 were collected and retrospectively analyzed. Patients with BHD (lateral center-edge angle [LCEA], 20°-25°) were matched 2:1 by age, sex, and body mass index (BMI) to control patients with normal acetabular coverage (LCEA, >25°-40°). Patient-reported outcome, MCID, and PASS were compared between the groups. Multivariate logistic regression analysis identified significant predictors of achieving the MCID and PASS in the BHD group. Results: The MCID in the BHD group was defined as 9.2, 13.7, 8.5, and 15.2 for the Hip Outcome Score–Activities of Daily Living, Hip Outcome Score–Sport Specific, modified Harris Hip Score, and iHOT-12, respectively. Threshold scores for achieving the PASS in both groups were 87.9, 76.4, 78.1, and 60.0. A total of 112 patients were identified as having BHD (LCEA, 20°-25°) and were matched to 224 controls. Both groups saw statistically significant increases in score averages over the 2-year period; however, the differences between them were not statistically significant ( P > .05 for all). There was no statistical difference in the frequency of the BHD and non-BHD cohorts achieving the MCID on at least 1 threshold score (86.6% vs 85.6%, P = .837) and the PASS (78.6% vs 79.8%, P = .79). There was, however, a statistically significant difference between the rates of patients with and without BHD achieving the PASS on the modified Harris Hip Score threshold (62.5% vs 74.5%, P = .028). The final logistic models demonstrated that lower BMI (odds ratio [OR], 0.872; P = .029), lower preoperative alpha angle (OR, 0.965; P = .014), and female sex (OR, 3.647; P = .03) are independent preoperative predictors of achieving the MCID, while lower preoperative alpha angle (OR, 0.943; P = .018) and self-reported limp (OR, 18.53; P = .007) are independent preoperative predictors of achieving the PASS. Conclusion: Outcome improvements in patients with BHD who are undergoing arthroscopic treatment with capsular closure for FAIS are not significantly different from patients with normal acetabular coverage. Lower BMI, lower alpha angle, absence of limp, and female sex are preoperative predictors of achieving meaningful clinically significant outcome improvements in patients with BHD.

What is the Role of Kinesiophobia and Pain Catastrophizing in Outcomes After Hip Arthroscopy for Femoroacetabular Impingement Syndrome?

“…As such, patients were considered to have achieved MCID if they achieved the respective outcome end point on at least 1 of the administered questionnaires. 49 Our methodology here is in line with adopted and accepted FAI, KINESIOPHOBIA, AND PAIN CATASTROPHIZING e99 methods previously reported and supported in the literature. 45,[49][50][51][52] Statistical Analysis All data were screened to determine whether parametric statistical assumptions were met before analysis.…”

Defining the Clinically Meaningful Outcomes for Arthroscopic Treatment of Femoroacetabular Impingement Syndrome at Minimum 5-Year Follow-up

“…Inclusion criteria consisted of clinical and radiographic diagnosis of symptomatic FAIS, 13 failure of nonoperative management (physical therapy, activity modification, oral anti-inflammatory agents, and intra-articular cortisone injection), and a minimum 5-year follow-up. Exclusion criteria consisted of hip arthroscopy for an indication other than FAIS, previous ipsilateral hip surgery, signs of osteoarthritis (Tönnis grade >1), hip dysplasia (lateral center-edge angle of Wiberg [LCEA] <20°), 1 or a history of pediatric hip disorders (slipped capital femoral epiphysis, developmental hip dysplasia, avascular necrosis, etc).…”

Editorial Commentary: Arthroscopy for Borderline Developmental Dysplasia of the Hip: Selection Determines the Outcomes

“…The most lateral point of the acetabulum rather than the sourcil edge is often used, which would cause a typical mistake with a falsely high LCEA value. 35 Besides, the congenital difference in LCEAs between male and female populations must not be neglected, 1,7 which might have resulted in the superior outcomes of the female BDDH patients shown in the current review by Kuroda et al 25 Although an LCEA slightly less than 25 may represent a significant structural abnormality in male patients, it is possibly a normal anatomic variant in female patients. 1,7,25 This difference clearly indicates a need to set different criteria for BDDH based on sex.…”

“…First, patients with real BDDH should be distinguished and selected. Normally, BDDH is defined by a lateral center-edge angle (LCEA) between 20 and 25 1,2,[10][11][12][13]17,21,23,[29][30][31][32] or between 18 and 25 according to some modifications. [3][4][5][7][8][9]15,18,20,33 Because the diagnosis of BDDH relies primarily on a small range of LCEAs, even a minor offset can cause misdiagnosis, leading to the heterogeneity of the BDDH cohort.…”

“…10,11,20 The advantage of fewer postoperative complications after hip arthroscopic procedures in BDDH patients has been validated in many short-to mid-term follow-up studies. [1][2][3][4][5][6][7][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] Meanwhile, it is apparent that suboptimal outcomes increase as the follow-up period increases and could reach an overall rate of 33% according to a 5-year follow-up study. 8,36 More long-term high-grade evidence is needed to analyze the impact of different characteristics of BDDH patients on their prognosis after arthroscopy to form a detailed description of which BDDH patients can achieve optimal results with arthroscopy.…”