Cotter, Eric J.

Abstract Background: Prior studies have evaluated the efficacy of subchondroplasty for the management of subchondral cysts of the knee, yet few studies to date evaluate minimum 2-year outcomes following subchondroplasty of the acetabulum. Purpose: The purpose of this study was to evaluate minimum two-year outcomes following arthroscopic subchondroplasty for the treatment of acetabular subchondral cysts and to identify variables associated with total hip arthroplasty (THA) conversion following subchondroplasty. Study Design: Cases Series, Level of Evidence IV. Methods: A retrospective review of prospectively maintained data was performed on patients who underwent primary hip arthroscopy May 2019 to September 2021 by a single surgeon. Consecutive patients who underwent subchondroplasty for acetabular subchondral cysts with minimum two-year follow-up were identified. Demographics, magnetic resonance imaging (MRI), intraoperative findings, and clinical outcomes were evaluated. Cross-sectional area of the subchondral cysts was measured on MRI. Clinical outcomes included Hip Outcome Score–Activities of Daily Living (HOS-ADL), HOS–Sports Subscale (HOS-SS), international Hip Outcome Score-12 (iHOT-12), and visual analog scale for pain (VAS-Pain). Conversion to THA was recorded. The patients who converted to THA were compared to those who did not. Continuous variables associated with THA conversion were analyzed with receiver operating characteristic (ROC) curves to identify thresholds associated with THA conversion. Results: Twenty-nine patients underwent subchondroplasty for acetabular subchondral cysts with minimum two-year follow up (age: 48.2±11.1 years, body mass index: 29.9±6.6kg/m2, 52.0% female). The THA-free survivorship rate was 62.1%. Patients who achieved THA-free survivorship had smaller subchondral cysts (88.5±59.2 mm2 vs. 147.1±54.8, P=0.013) and a lower prevalence of high-grade femoral head chondral defects (16.7% vs. 54.5%, P=0.048) compared to patients who converted to THA. ROC analysis identified patients with a subchondral cyst <133 mm2 were 21.3 times more likely to achieve THA-free survivorship (P=0.001). The THA-free survivors demonstrated significant improvements across all measured PROs (P≤0.015). Conclusions: Subchondroplasty for acetabular subchondral cysts demonstrated a 62.1% THA-free survivorship at minimum 2-year follow-up, with survivors demonstrating significantly improved PROs. Patients with cysts <133 mm2 were 21.3 times more likely to achieve THA-free survivorship than patients with larger cysts. Keywords: Hip, Acetabulum, Subchondral Cysts, Subchondroplasty

Background: Meniscal allograft transplantation (MAT) has been shown to provide clinical benefits in patients with symptomatic meniscal deficiency in the short term and midterm. There is, however, a paucity of data regarding long-term outcomes after MAT using fresh-frozen allografts and the bridge-in-slot technique. Purpose: To report clinical outcomes and revision rates after primary MAT with fresh-frozen allografts and the bridge-in-slot technique in a large case series of patients at a 10-year minimum follow-up. Study Design: Case series; Level of evidence, 4. Methods: A retrospective review of prospectively collected data was performed on patients undergoing primary MAT between 2001 and 2012. Lysholm, International Knee Documentation Committee subjective form, and Knee injury and Osteoarthritis Outcome Score subscales were collected preoperatively and at 1-, 2-, 5-, and minimum 10-year follow-ups. Cox proportional hazards modeling was used to identify variables associated with reoperation and failure, defined as revision MAT or conversion to arthroplasty. Reoperation was defined as a subsequent surgical intervention on the transplanted meniscus, including partial or total meniscectomy, meniscal repair, or failure as defined in the previous sentence. Results: A total of 174 patients undergoing MAT met the inclusion criteria and were followed for a mean of 12.7 ± 2.7 years (range, 10.0-21.0 years). The mean age at surgery was 28.3 ± 10.1 years. The patients were predominantly female (n = 92; 53%), and medial MAT was the most commonly performed procedure (n = 91; 52%). Concomitant procedures were performed in 115 patients (66%), with the most common procedure being osteochondral allograft transplantation (n = 59; 34%). Patients demonstrated statistically significant postoperative improvements at all time points for all patient-reported outcome measures ( P ≤ .0001). A total of 65 patients (37%) underwent a meniscal reoperation at a mean time of 6.6 ± 5.5 years (range, 0.3-16.7 years) postoperatively. A total of 40 patients (23%) met the criteria for failure at a mean time of 7.3 ± 5.0 years (range, 1.0-17.4 years) after MAT, with 22 of these patients having undergone a previous meniscal reoperation. At the final follow-up, 13 patients (7%) had undergone revision MAT and 27 (15%) had converted to arthroplasty. The MAT survival rates free of meniscal reoperation and failure were 73% and 85% at 10 years and 60% and 72% at 15 years, respectively. At the time of the final follow-up, 86% of patients reported that they were satisfied with their overall postoperative condition. Conclusion: Primary MAT demonstrates efficacy and durability with high rates of patient satisfaction at a minimum 10-year follow-up. Patients should be counseled that although reoperation rates may approach 40% at 15 years, rates of overall revision MAT and conversion to arthroplasty remain low at long-term follow-up.