Meniscal Allograft Transplantation
Abstract & Commentary
Synopsis: This study evaluates intermediate term results of meniscal allografts. Pain and function improved, however function remained limited and more than one third of the grafts tore during the period of the study.
Source: Rath E, et al. Meniscal allograft transplantation. Two to eight year results. Am J Spts Med. 2001;29(4): 410-414.
We have come full circle in our understanding of the importance of the meniscus in the normal knee. Complete meniscectomy remained the treatment of choice for meniscal tears well into the 1980s. Meniscal repair has only recently become popular, and there is no paucity of meniscal deficient knees in our population. Because of the known likelihood of progressive arthritis in this population, meniscal allograft transplantation has been advocated. Allografts are not a panacea, however. It is a technically difficult procedure to perform, there have been reports of graft shrinkage and tearing, and clinical results are mixed.
In a prospective study, Rath and associates reviewed the results of 27 meniscal allografts transplanted over a period of 7 years. A bone-plug technique was used in all but 1 case. Their inclusion criteria included postmeniscectomy knees with normal or corrected mechanical alignment. Their exclusion criteria was severe degenerative joint disease (including grade IV chondrosis). At an average follow-up of 5.4 years, 22 implants in 18 patients were evaluated using a SF-36 and IKDC evaluation.
Ten patients underwent subsequent arthroscopy, usually for a meniscal tear. The graft completely healed to the bed in all patients. Histological study of retrieved allograft tissue demonstrated decreased cellularity (50%) and decreased staining for PDGF-alpha, TGF-beta, and IGF-1 as compared to normal menisci. At final follow-up for the entire group, SF-36 scores in several categories and IKDC functional scores improved significantly from preoperative values. Rath et al conclude that although meniscal allograft transplantation relieved pain and improved function, it does not result in normal functioning menisci.
Comment by Mark D. Miller, MD
This is an interesting study of a controversial subject. The indications for meniscal allograft transplantation remain as elusive as obtaining consistently good results. There is no question that these grafts heal to the host bed reliably. The issue remains as to how well they function. The present study suggests that we cannot replicate the native menisci, but we can at least give intermediate term clinical improvement for these patients. The tear rate of these grafts is high and the function, as evidenced by these cellular markers, is not normal. Rath et al should be congratulated for their enterprise in evaluating the histology and cellular markers in the retrieved specimens. This is our first glimpse into what is going on functionally with these grafts. The results are not surprising, and mirror clinical experience. The question remains—are they good enough to continue to offer this difficult (both from a technical standpoint and an insurance approval standpoint) procedure?
Dr. Miller, Associate Editor of Sports Medicine Reports, is Associate Professor, UVA Health System, Department of Orthopaedic Surgery, Charlottesville, Va.