Poster 220: Outcomes of Hip Arthroscopy in Patients with Hip-Spine Syndrome: A Matched-Pair Controlled Study with Minimum Two-Year Follow-Up

Abstract

Objectives:

Hip–spine syndrome is a phenomenon commonly seen in the geriatric population presenting with concurrent hip osteoarthritis and lumbar spine degenerative disease. Secondary hip-spine syndrome can develop when compensatory stresses are placed on the lumbosacral spine due to pathologies that limit hip range of motion, such as femoroacetabular impingement (FAI). The literature remains conflicted on the impact of hip arthroscopy in hip-spine syndrome and there is a paucity of studies that report long term outcomes. The purpose of this study was to conduct a matched-pair analysis to assess the effects of lumbar spine pathology on minimum two-year clinical outcomes of patients undergoing hip arthroscopy for FAI.

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 FAI with evidence of concomitant lumbar spine pathology. Importantly, all patients participated in the same postoperative protocol and underwent capsular management via the previously published puncture capsulotomy technique. Additionally, included patients had failed conservative treatment, a minimum of two-year follow-up, and symptoms of low back pain with objective evidence of lumbar pathology (i.e., herniation, degenerative disc disease, stenosis, spondylosis, etc.) at the time of surgery. Patients were excluded if they had any previous hip surgery, evidence of hip dysplasia (lateral center edge angle ≤25°), or advanced osteoarthritis (Tönnis ≥2). Patients in the hip-spine (HS) cohort were matched 1:1 by age within 5 years, body mass index (BMI) within 5.0 kg/m², and sex to a matched control (MC) cohort. The MC cohort lacked subjective or objective evidence of lumbar spine pathology. The following patient- reported outcomes (PROs) were recorded in each cohort: Modified Hip Harris Score (mHHS), International Hip Outcome Tool-33 (iHOT-33), Non-Arthritic Hip Score (NAHS), rates of revision arthroscopy, and conversion to total hip arthroplasty (THA).

Results:

A total of 60 patients with lumbar disease (HS; age = 39.5 ±10.2, BMI = 26.3 ±4.0, 48.3% Female) were matched with 60 control patients (MC; age = 39.4 ±11.6, BMI = 25.7 ±4.1, 48.3% Female). At baseline, all PROs were significantly lower in the HS cohort (all p<0.05). At one-year follow-up, the HS cohort exhibited a greater magnitude of improvement in all PROs, with significant differences in the NAHS (p = 0.006). Additionally, a higher percentage of patients in the HS cohort achieved the minimal clinically important difference (MCID) threshold for all outcome measures at one-year, and a significant difference was identified in the NAHS (p = 0.026; Tables 1&2). At two-year follow-up, all PROs were significantly lower in the HS cohort (all p<0.05), however at three- and five-year follow-up no differences were identified between cohorts in mean PROs, magnitude of improvement, or percentage of patients achieving MCID thresholds (all p>0.05). No significant differences in the rates of revision (0% vs. 0%) or conversion to THA (5.3% vs. 3.4%) were identified between cohorts (all p>0.99).

Conclusions:

While patients with a history of lumbar spine pathology achieved lower short-term outcomes after hip arthroscopy, these differences were mitigated when follow-up was expanded to 3- and 5- years (Figure 1). While the HS cohort exhibited lower baseline PROs at the time of surgical intervention, these patients had an equal or greater magnitude of improvement across all time points. This study’s findings have implications for the shared decision-making process and managing patient expectations prior to undergoing hip arthroscopy for FAI. Although it may take greater than two years, patients with hip-spine syndrome can attain clinically meaningful improvement in hip function following hip arthroscopy for FAI.