Introduction: Lateral meniscectomies lead to degenerative arthritis and therefore meniscus transplantation has been considered. In literature, this procedure appears to have good clinical results. The aim of this study was to evaluate our clinical results at mid-term follow-up and to correlate these results to the morphology and position of the transplanted meniscus.

Material and methods: Twenty-eight patients operated in 4 surgical centers, were retrospectively reviewed following lateral meniscal allograft transplantation. The mean age of the patients was 34 years (range, 18 to 50 years). Before surgery, all these patients suffered of permanent lateral femorotibial pain without radiological knee arthritis. The knees were all stable or stabilized, without axial malalignment of the lower limbs or corrected by a concomitant high tibial osteotomy. Arthroscopic procedure was performed for 9 patients and arthrotomy for 19 patients. Different techniques of fixation of the transplant were used, with or without bone plugs. The associated procedures were 2 ACL reconstruction, 3 high tibial varus osteotomies, and 1 mosaicplasty. The IKDC score were used for the analysis of the functional results. An arthroTDM or an arthro MRI was used to analyse the morphology and position of the transplanted meniscus.

Results: The mean follow-up was 35 months (range, 12 months to 6 years). The mean post-operative subjective IKDC score was 65.5 points (range, 19.5 to 89 points). There were 2 failures associated with a fast arthritic evolution and 2 functional bad results. The others 24 patients (85%) were satisfied or very satisfied, with a real improvement of the pain and the function. Seventeen patients (60%) have started again a sportive activity superior than the one pre-operating. At the last follow-up, all transplanted meniscus have healed, but the morphology and position of the transplanted meniscus was not always normal with absence of the middle segment in 3 cases; its extrusion in 9 cases, a posterior segment shortened or partially hurt in 5 cases and its absence in 3 cases. Better results were associated with good meniscus positioning and morphology.

Discussion: Our works confirm that lateral meniscal allograft is a therapeutic option with favourable results in terms of pain reduction and functional improvement in the medium term for symptomatic patients after lateral meniscectomy. Our results are comparable with those of the literature. The allograft is technically reliable, reproducible notably for the methods of fixation. A long term follow-up is necessary to evaluate the benefit of these grafts on the protection of the cartilage.