Scintigraphic assessment of rabbit knee joints after meniscal allograft transplantation

It has been shown that meniscal allografts show capsular ingrowth in meniscectomized knees. However, it remains to be established whether a transplanted meniscus can prevent degenerative changes in the long term. In the present study, scintigraphy was used to evaluate degenerative changes in rabbit knees after meniscectomy only and after meniscectomy followed by immediate or delayed meniscus transplantation.

Experimental study.

Twenty-eight rabbits were divided into 4 groups. Three rabbits developed infective arthritis and were excluded from the study. In group A (6 animals), 2 rabbits underwent medial meniscectomy, 3 rabbits underwent transplantation with a freshly harvested medial meniscal allograft immediately after meniscectomy, and 1 rabbit underwent a sham operation. In group B (6 rabbits) medial meniscectomy was performed. Group C (6 rabbits) underwent meniscal transplantation immediately after meniscectomy. Group D (7 rabbits) underwent delayed allograft transplantation at 6 weeks after meniscectomy. The animals in group A underwent scintigraphy at 6 weeks after surgery. In the other groups, scintigraphy was performed at 1-year follow-up. Contour changes of the knee joints and uptake of radiolabeled diphosphonate in the subchondral bone were evaluated.

No animals in group A showed any abnormalities scintigraphically. Medial compartment changes in group B were more pronounced than in group C, but this difference was not statistically significant. A significant increase in contour changes of the femoral condyle was seen in group D.

Immediate meniscal allograft transplantation did not result in a significant protecting effect on articular cartilage against osteoarthritic degeneration on a long-term basis. Delayed meniscal transplantation revealed even more degenerative changes of articular cartilage than meniscectomy without transplantation.