Partial Resurfacing of the Knee with the BioPoly Implant: Interim Report at 2 Years.

Nathwani, Dinesh MB, ChB, MSc, FRCS(Tr&Orth); McNicholas, Michael BSc, MB, ChB, FCRS(Ed&Glasg), MD, FRCSEd(Tr&Orth), FFSEM RCSI; Hart, Alister MA, MD, FRCSG(Orth); Miles, Jonathan MD, FCRS(Orth); Bobic, Vladimir MD, FRCSEd
doi: 10.2106/JBJS.OA.16.00011
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Background: Current treatments for focal chondral and osteochondral lesions of the femoral condyle have been associated with variable outcomes. We conducted a clinical trial of the BioPoly RS Partial Resurfacing Knee Implant to address this unmet need.

Methods: We performed a single-arm, prospective study in which 33 patients with focal cartilage lesions affecting the femoral condyle were managed with the BioPoly RS Partial Resurfacing Knee Implant. Knee injury and Osteoarthritis Outcome Score (KOOS) scores, a visual analog scale (VAS) for pain, the Short Form-36 (SF-36) physical component score , and the Tegner activity score were used to assess outcomes preoperatively and at 6 months, 1 year, and 2 years postoperatively. The KOOS outcomes at 2 years were compared with historical outcomes following microfracture treatment.

Results: We found significant and clinically meaningful improvements in the KOOS scores, VAS pain score, and SF-36 physical component score (p < 0.025) when the values at all 3 postoperative time points were compared with the preoperative scores, and we also found significant improvements when the Tegner activity score at 2 years was compared with the preoperative score (p < 0.025). More than half of the cohort of patients had had a previous failure of cartilage-repair procedures. No significant differences were detected between younger patients (<=40 years) and older patients (>40 years). When compared with historical microfracture data, the BioPoly RS Implant demonstrated significantly superior KOOS scores for quality of life and sports.

Conclusions: The present study indicated that the BioPoly RS Partial Resurfacing Knee Implant is safe, that it resulted in significantly improved knee function by 6 months, and that this improvement was sustained for 2 years regardless of patient age. The BioPoly RS Knee Implant allows return to a higher level of sporting activity than microfracture. Additional long-term follow-up is needed to determine the long-term effects of the device.

Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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(C) 2017 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of The Journal of Bone and Joint Surgery, Incorporated.