Addition of collagen during medial meniscal root repair (MMRR) may improve meniscal root healing minimising fibrous scar tissue formation. The purpose of this study was to verify the effect of atelocollagen on MMRR using the modified Mason–Allen stitch when compared with that of the conventional pullout repair by assessing the clinical and radiological outcomes.

It was hypothesised that atelocollagen would enhance the healing effect on the meniscal root following MMRR. Moreover, we presumed that MMRR with atelocollagen application might reduce meniscal extrusion by promoting healing.

A total of 47 patients who underwent MMRR using the modified Mason–Allen stitch between 2015 and 2016 were included, and they were divided into group A (atelocollagen application; n=25) and group R (MMRR without atelocollagen application; n=22). The postoperative clinical outcomes, radiological outcomes, and meniscal root healing and medial compartment cartilage status on follow-up magnetic resonance imaging (MRI) were compared between the two groups.

Mean follow-up duration was 26.4±4.8 months in group A and 27.1±5.2 months in group R (p=0.598). Mean duration from surgery to follow-up MRI was 12.5±1.4 months in group A and 12.7±1.2 months in group R (p=0.604). The subjective knee scores improved significantly in both groups at the last follow-up (all, p<0.001). The Kellgren–Lawrence (K–L) grade progressed in 16% and 22.7% in group A and group R, respectively (p=0.351). Follow-up MRI showed progression of cartilage loss in the medial compartment in 28% and 40.9% in group A and group R, respectively (p=0.355). In terms of meniscal root healing, 18 (72%) and 12 (54.5%) patients had complete healing, and 6 (24%) and 8 (36.4%) patients had partial healing in groups A and R, respectively. The mean value of the intra-meniscal signal intensity (IMSI) of the meniscal root based on MRI in group A was significantly lower than that in group R (p<0.001). The medial meniscal extrusion in groups A and R decreased by 0.2±0.1mm and 0.1±0.3mm following MMRR without significant differences (p=0.056 and p=0.229, respectively). The IMSI presented significant negative correlations with the root healing status and significant positive correlations with K–L grade progression (p<0.05).

Atelocollagen application during MMRR yielded lower IMSIs, suggesting better healing, than did conventional pullout root repair. However, this technique could not demonstrate beneficial effects on meniscal extrusion.

III, retrospective case-control study.