Summary

MACI has clinically significant results with mean post-operative follow-up greater than two years in improving patient reported outcome measures in patients requiring bone grafting.

Abstract

Purpose

Matrix-induced autologous chondrocyte implantation (MACI) is a regenerative procedure aimed to recreate a hyaline-like repair tissue, restoring a biologically and biomechanically valid articular surface with durable clinical results. The purpose of this study is to assess patient reported outcome measures (PROMS) to characterize and elucidate whether the excellent results with the ACI or CACI (autologous bone graft and a periosteal replacement graft) and autologous bone grafting (ABG) sandwich technique can be demonstrated using the MACI graft in place of the previous ACI or CACI “sandwich” procedures.

Methods

& Materials:
A cohort study of a prospectively followed patients was undertaken. The study population included patients who underwent MACI procedures with bony involvement, bone grafting, or sandwich technique with minimum 6-month follow-up. The primary study endpoint was defined as an improvement of pain scores as measured at a minimum of 6M post-operative compared to preoperative value. Secondary endpoints included IKDC, KOOS, Lysholm, and SF-12 scores. All procedures were performed by the senior author, a fellowship-trained sports orthopaedic surgeon. Differences in mean outcomes were assessed using generalized linear mixed model with a Poisson distribution and a random patient effect to account for correlations over time. All P-values were adjusted for multiple comparisons using the Tukey-Kramer method with alpha less than 0.05 considered statistically significant.

Results

16 patients with mean age 25.4 years underwent MACI for symptomatic osteochondral lesions. Mean follow up was 29.8 months (range 5-61 months). 81% of patients had a single defect treated. Differences from pre-operative baseline to most-recent follow-up was collected for each of the following modalities: IKDC (47.84 to 81.25; p < .001), Lysholm (58.19 to 86.31; p < .001), KOOS pain (65.80 to 90.63; p < 0.002), KOOS symptom (59.60 to 83.48; p < 0.002), KOOS ADL (73.35 to 97.06; p < .001), KOOS sports (51.56 to 76.25; p < 0.024), KOS QoL (42.19 to 62.11; p < 0.054), PSF-12 (41.02 to 49.62; p < 0.006), MSF-12 (52.00 to 57.82; p < 0.046). Statistically significant improvements were noted at most recent follow up in 9 of 11 outcome measures. Mean pain frequency improved from 6 to 2 (p < 0.001) while pain severity changed from 3.9 to 2.3 (p = 0.083).

Conclusion

MACI has clinically significant results with mean post-operative follow-up greater than two years in improving patient reported outcome measures in patients requiring bone grafting.