Factors Associated With Disease Progression in the Contralateral Hip of Patients With Symptomatic Femoroacetabular Impingement: A Minimum 5-Year Analysis

Abstract

Background: Femoroacetabular impingement (FAI) is one of the most common causes of hip osteoarthritis, yet the factors controlling disease progression are poorly understood. Purpose: To investigate rates of initial and subsequent symptoms in the contralateral hip of patients with FAI, and identify predictors of disease progression (symptom development and surgical intervention) in the contralateral hip. Study Design: Cohort study; Level of evidence, 2. Methods: This prospective study included a minimum 5-year follow-up of the contralateral hip in 179 patients undergoing FAI surgery. Symptoms (moderate pain) and surgical progression were monitored. Univariate and multivariate analyses compared patient-specific and imaging characteristics of symptomatic patients with those who remained asymptomatic to identify factors associated with disease progression. Results: A total of 150 patients (84% follow-up) were followed for a mean of 7.1 years (range, 5-11 years). Thirty-nine of these patients (26% [39/150]) had contralateral hip symptoms at initial evaluation. Of those without contralateral hip symptoms at initial evaluation, 32% (36/111) had developed contralateral hip symptoms by latest follow-up. Those who developed symptoms during the study period had a lower anteroposterior head-neck offset ratio (0.153 vs 0.165; P = .005), decreased total arc of rotation in 90° of flexion (39.9° vs 51.1°; P = .005), and decreased external rotation in 90° of flexion (28.6° vs 37.1°; P = .003) compared with those who never developed symptoms. Age, sex, body mass index, alpha angle, lateral center-edge angle, internal rotation in flexion, and University of California, Los Angeles (UCLA), activity score were similar between these groups. Those with contralateral symptoms at initial evaluation progressed to contralateral surgery at a rate of 41% (16/39) and those who developed contralateral symptoms during the study period progressed to contralateral surgery at a rate of 28% (10/36). Among those with contalateral hip symptoms (either present initially or developed during study period)), younger age (24.6 vs 34.1 years; P < .001) and baseline UCLA activity score ≥9 (P = .003) were associated with progression to surgery. By Kaplan-Meier analysis, 64%, 54%, and 48% of patients remained free of contralateral hip symptoms at 2, 5, and 10 years. Conclusion: At a mean follow-up of 7.1 years, significant symptoms in the contralateral hip of patients with FAI were present in approximately 50% of patients. FAI disease progression (symptom development and surgical intervention) was associated with decreased hip rotation arc, decreased external rotation, and decreased head-neck offset ratio. In symptomatic patients, younger age and UCLA activity score ≥9 were associated with progression to surgery. These findings represent important factors for patient counseling and risk modeling in FAI.

Modern Hip Arthroscopy for FAIS May Delay the Natural History of Osteoarthritis in 25% of Patients: A 12-Year Follow-up Analysis

“…2 In 1 prospective study of 150 patients who underwent unilateral hip arthroscopy, at the 7.1-year follow-up 75 of 150 patients (50%) had developed symptomatic FAIS and 26 of 150 (17%) went on to surgery. 9 Although no analysis of radiographic progression of arthritis was performed—likely because of the abbreviated time span—this study by Khan et al helped to better contextualize the symptom-based natural history of patients who initially have FAIS.…”

“…Even though not all hips are symmetrically designed, the contralateral hip has been established by Wyles et al 25 to be an appropriate comparison in the literature. Khan et al 9 demonstrated at 7-year follow-up that half the contralateral hips become symptomatic and nearly one-fourth progress to hip arthroscopy, suggesting that there may be more symmetry than expected. It is well established that symptomatology does not always match imaging, but we attempted to mitigate this by confirming that both hips had radiographic features of FAIS in each of the 100 patients.…”

“…The vast majority (91%) of changes were 0 or 1 To ¨nnis grade. Assuming the nonoperative hip to be a valid internal control and surrogate for the natural history of FAIS, as established in 2 key studies by Wyles et al 25 and Khan et al, 9 the natural history of FAIS resulted in radiographic progression of osteoarthritis 48% (48/100) of the time and no change only 52% (52/100) of the time. This statement alone, that nearly half of patients progress to a worse grade of arthritis 12 years later, is meaningful to share when counseling patients who seek to better understand the radiographic course of their pathophysiology.…”

“…With a 74% follow-up at 20 years in a cohort of 172 patients with a mean age of 47 years, patients with radiographic signs of cam and dysplasia were the fastest to progress to THA. Khan et al 9 similarly evaluated the contralateral hip for those who had already undergone hip arthroscopy for FAIS, with 84% follow-up at 7 years, and projected that 52% of contralateral hips would become symptomatic and 23% would undergo arthroscopy at 10 years of follow-up. The purpose of our study was to (1) characterize the natural history of FAIS with respect to radiographic joint degeneration and (2) understand the effect of modern hip arthroscopy indications and techniques by radiographically comparing the hips of patients who had undergone unilateral primary hip arthroscopy with a minimum follow-up of 10 years.…”