Poster 188: The Role of Chondrolabral Junction Breakdown on Functional Outcomes Following Hip Arthroscopy at Minimum Two-Year Follow-Up

Abstract

Objectives:

Intraarticular hip pathologies in non-arthritic hips, including acetabular labral tears and osseous deformities or femoroacetabular impingement (FAI) of the femoral head and acetabulum, have detrimental effects on hip biomechanics, synovial fluid dynamics, and the acceleration of early osteoarthritis. Consequently, prompt treatment of persistent symptoms from labral tears and/or FAI that fail conservative management frequently requires hip arthroscopy. Prior literature has identified older age and more advanced radiographic (e.g., high Tönnis grade) and/or arthroscopic (e.g., higher Outerbridge grade) osteoarthritis as risk factors for poor outcomes following hip arthroscopy. In addition, studies have discussed the significance of “chondrolabral junction” (CLJ) damage on hip arthroscopy outcomes; however, prior literature has considered CLJ damage with reference to chondral or labral damage separately. The specific impact of damage to the transition zone cartilage between the labrum and articular cartilage—the chondrolabral junction—has not been explored. We propose that assessment of CLJ damage through a validated classification system is essential to understand the prognostic impact of this region on functional outcomes following hip arthroscopy and potentially guide future surgical modalities. Thus, the purpose of this study was to conduct a cohort analysis to assess the impact of CLJ damage on clinical functional outcomes at minimum two years following hip arthroscopy.

Methods:

An institutional review board-approved retrospective review of a prospectively collected, single-surgeon database was performed to identify patients who underwent hip arthroscopy for treatment of symptomatic labral tears secondary to FAI. Included patients had failed conservative treatment and had a minimum of two-year follow-up. Patients were excluded if they had any previous hip surgery or advanced osteoarthritis (Tönnis>2). Operative notes and arthroscopic images for consecutive patients were reviewed for evaluation of intraoperative findings, including, most notably, CLJ damage. The previously published Beck classification of transition zone cartilage injury was used to grade CLJ damage for all patients; patients with a grade of 0-2 were stratified into the “mild CLJ damage” cohort, and those with a grade of 3-4 were stratified into the “severe CLJ damage” cohort. Other operative findings collected included Outerbridge classification of the articular cartilage and the Beck classification of labral tears. Preoperative hip and pelvic radiographs were reviewed for all patients. The following patient reported outcome measures (PROMs) were assessed for all patients: International Hip Outcome Tool-33 (iHOT-33), Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sports Specific Subscale (HOS-SSS), Non-Arthritic Hip Score (NAHS), Modified Hip Harris Score (mHHS), and visual analog score (VAS) for pain. Linear mixed effects models adjusted for age, sex, body mass index (BMI), Beck labrum score, labral treatment (debridement versus repair), FAI type, and use of adjuvant treatment for cartilage damage (BMAC or microfracture) were used to compare PROM scores at enrollment, 3 months, 6 months, 1 year, 2 years, and 5 years.

Results:

Overall, 200 patients met inclusion/exclusion criteria, with average follow-up time of 3.63 ± 1.21 years. A total of 96 patients with severe CLJ damage (age: 34.8 ± 10.5 years, BMI: 25.3 ± 3.3 kg/m², 33.3% female) were compared with 104 patients with mild CLJ damage (age: 38.4 ± 11.8 years, BMI: 25.5 ± 4.4 kg/m², 48.0% female) (Table 1). Patients with severe CLJ damage had significantly larger labral tear sizes, higher Beck labrum grades, and higher rates of combined FAI which were surgically treated (P < 0.05 for each; Table 2). Linear mixed effects modeling showed that HOS-ADL, NAHS, and VAS scores were significantly inferior in the severe CLJ group at enrollment and 3-month follow-up; HOS-ADL and NAHS remained significantly lower for the severe CLJ cohort at 6-month and 1-year follow-up. However, by 2-year follow-up, the severe CLJ group only had lower NAHS scores; by 5-year follow-up, there were no differences between cohorts in any reported PROMs (Table 3). Furthermore, at 2- and 5-year follow-up, there were no differences between mild versus severe CLJ cohorts in percentage of patients achieving any clinical thresholds, including minimally clinically important difference (MCID), patient acceptable symptomatic state (PASS), or substantial clinical benefit (SCB) (P > 0.05 for each) (Table 4).

Conclusions:

While patients with severe CLJ damage had worse functional metrics at baseline and through 12 months postoperatively following hip arthroscopy, these differences decreased at 2 years and were mitigated entirely at 5 years. These improvements are further supported by 78 (iHOT-33), 66 (HOS-ADL), 71 (HOS-SSS), 79 (NAHS), and 76 (mHHS) percent of patients with severe CLJ damage achieving MCID for these functional metrics, at 2 years; these percentages did not differ significantly from patients with mild CLJ damage. These data suggest that while significant CLJ breakdown may account for significantly increased pain and decreased functional status upon initial clinical presentation and up to 1 year postoperatively, these patients can improve significantly beyond 1 year and achieve satisfactory functional outcomes at 2 and up to 5 years. These findings have implications for managing patient expectations prior to hip arthroscopy for FAI. Although it may take more than 12 months, patients with severe CLJ damage can be counseled that they are still likely to attain clinically meaningful midterm improvements in functional outcomes following hip arthroscopy for FAI.