Poster 285: Two-Year KOOS Improvement after Unloading Treatment With Implantable Shock Absorber in Post-Meniscectomy Patients

Abstract

Objectives: Meniscectomy is a common orthopaedic procedure designed to improve symptoms. However, partial or full meniscectomy can reduce the structure’s ability to absorb and distribute normal joint load, which can result in post-meniscectomy pain. Subjects with and without previous meniscectomy and knee OA were treated with an implantable shock absorber (ISA) to unload the medial compartment. The purpose of this study was to compare subjects with and without previous meniscectomy who were treated with the ISA to evaluate if prior meniscectomy impacted outcomes scores. The objective was to determine if prior meniscectomy impacted two-year KOOS outcomes for patients treated with an implantable shock absorber. Methods: Eighty-one (81) subjects had the ISA implanted, and 23 subjects (28%) previously underwent partial (22) or full (1) medial meniscectomy. Subjects in the medial meniscectomy arm were 50.9 years old compared to 51.4 years old in the non-meniscectomy arm (p=0.8). The two arms were comparable for other baseline demographics, such as BMI, OA disease severity and duration of symptoms. Baseline and 2-year improvements in KOOS subscales were recorded. Results: Subjects with and without previous meniscectomy reported similar improvements in KOOS scores at two years. The post-meniscectomy group reported KOOS Pain improvement of 41.3 points from baseline, compared to a 47.3 point improvement in the non-meniscectomy group (p=0.2584) at two years. Similarly, the meniscectomy group reported a 43.6 improvement in KOOS ADL, compared to a 45.9 point improvement in the non-meniscectomy group (p=0.7075). Subjects reported similarly high levels of improvement in the post-meniscectomy arm compared to the non-meniscectomy group (38.2 vs. 51.4, p=0.1108) on the Sports/Rec Activities scale of KOOS. Through two years, none (0%) of the meniscectomy group underwent a conversion to arthroplasty, and study safety events were comparable between the two arms (p=0.2109). Conclusions: At two years, the implantable shock absorber provided dramatic improvement on KOOS subscales for subjects with prior meniscectomy and knee OA that is comparable to the improvement for subjects without history of meniscectomy. While this study population was more of a general OA population and not a sports-oriented population, the improvement in KOOS Sports/Rec was notable for the post-meniscectomy cohort. Given the attractive safety profile, the ISA is a potential treatment for patients with post-meniscectomy pain, and the treatment should be evaluated further in this population.