To demonstrate comparative KOOS Overall outcomes of an interpositional knee meniscus endoprosthesis versus non-surgical controls in the treatment of persistent post meniscectomy knee pain.
242 patients enrolled in a pooled population, randomized controlled trial (RCT) and single-arm study, comparing the investigational device to non-surgical standard of care. Of the first 100 patients enrolled, whose follow-up has exceeded 12 months, 65 patients were treated with the interpositional endoprosthesis device, and 35 were treated non-surgically. Validated KOOS scores at baseline, 6-week, 6-month, and 12-month time points were obtained from all patients. A “clinically significant improvement” was considered to be an increase of 20 KOOS points, (Roos et al.2003). The cohorts were compared at each time point using a two tailed t-test. All baseline cohort demographics and KOOS Overall score were not statistically different (p>0.05).
Improvement in KOOS Overall for the investigational and control cohorts at 6-months and 12-months were 23.0 and 7.6 points, and 28.8 and 11.3 points, respectively (Figure 1). These data show a statistically significant improvement, above the clinically meaningful threshold, in the investigational arm versus the control arm as early as 6 months (p<0.001) and continues through the 12-month timepoint (p<0.001).
At 12 months, 3 (4.6%) investigational vs. 5 (14.3%) control patients were deemed study failures, due to removal of the investigational device, or due to non-surgical control patients requiring surgical intervention, At 12 months, more patients progressed to knee arthroplasty procedures in the non-surgical, control group (n=4, 11.4%) than in the surgical, investigational group (n=1, 1.5%).
These early one year follow-up results of efficacy KOOS Overall score are encouraging. Further study of the clinical outcomes of these patients and their adverse events is ongoing, with long-term results of both the randomized controlled trial and the single-arm study to be reported in the future.