Sizing Meniscal Allograft for Transplantation
Meniscectomy has the potential to have devastating long-term consequences in young patients. Many procedures have been developed to address the changes caused by a meniscectomy, including tendon autograft meniscal replacement, meniscal engineering, and meniscal transplantation. Of these, meniscal transplantation has received the most attention and clinical applicability in recent years. It is an evolving technology that has shown clinical and physiologic efficacy in various studies. There have also been numerous techniques and modifications proposed for the transplantation procedure. This continuous refinement has been fueled by ongoing research and the contributions of expert opinion.
Preoperative sizing of the allograft is one aspect of meniscal transplantation that is continually debated. The importance of correct sizing has been considered by many authors and highlighted in recent biomechanical studies completed by Dienst et al. and Alhalki et al. Currently, there are two predominant methods for sizing the allograft: radiographic analysis, as proposed by Pollard et al., and magnetic resonance imaging interpretation as proposed by Haut et al. In Pollard et al.’s method, there is a correction made for magnification, and the width is then calculated on the anteroposterior radiograph of the knee by measuring from the tibial metaphyseal margin to the peak of the tibial eminence. The length is measured on the lateral radiograph and a 70% adjustment is made for the lateral meniscus and an 80% adjustment is made for the medial meniscus. Haut et al. used MRI parameters of the meniscus in order to predict the required allograft size, and most recently Prodromos et al. confirmed the accuracy of MRI in this application. However, the majority of contemporary studies have used radiographic measurements for sizing. Both methods have shown utility; however, they also have substantial standard deviations (SDs) of measurement and relatively large average error rates.
The need for accurate meniscal allograft size estimation and the purported error associated with contemporary sizing methods led us to investigate other feasible techniques for accurately determining the size of the required meniscal allograft. Furthermore, it has recently been suggested that patient height and weight may provide data that can be used to calculate accurate size estimates of meniscal allografts. In the current study, 930 menisci have been analyzed in the context of the donor’s height, weight, and gender. It is our hypothesis that this demographic data can be used to develop a reproducible formula that can be applied to future meniscal allograft sizing.