Morphometric profiles of some grafts commonly used for anterior cruciate ligament reconstruction

Abstract

The Anterior cruciate ligament (ACL) is a vital knee joint ligament that is commonly damaged in sporting activities. Choice of graft type (allograft or autograft) by surgeons is often based on their training and the observed clinical outcomes and success rates in their practices. The quadriceps (QT), patellar (PT) and semitendinosus (ST) tendons are the commonly used grafts for ACL reconstruction. This study presents the morphometric profiles (e.g. the harvestable surface area, tendon length and widths etc.) of the QT, PT and ST. In addition, the tenocyte distribution and collagen deposition of the tendons were also quantified and compared. A total of 79 adult cadavers of South Africans of European Ancestry were used. Dissections of the anterior and medial aspects of the mid-thigh, knee and mid-leg were conducted to expose these tendons. The tendon morphometries were done in situ by tracing the margins and curvatures of the QT or PT on a wax paper. The tracings were scanned and then the morphometries were performed using an ImageJ software. Measurements on the ST were carried out using threads and digital calliper. The length of limb was also measured, and this was used to normalize all the measures. To compare the tendon ultrastructure, tissue samples of the QT, PT and ST were collected from male and female cadavers and then processed for histology. Tenocyte distribution from a H & E– and collagen deposition from a Masson Trichrome– stained sections were analyzed using an ImageJ software. The results showed that all measures produced a high degree of reproducibility using a Lin’s concordance test. The limb length for both limbs was similar in the two sexes and the male limbs were significantly longer than the female. For the QT, there was no side or sex difference in all the measures except for the SDWQT that was sexually dimorphic. Some paired parameters showed a strong correlation (e.g. SDWQT vs CDWQT and SAQT vs LOTQT). For the PT, there was also no significant difference in all the measures for both sides or sexes. Also, some paired parameters showed a strong correlation (SAPT vs LOTPT; SPWPT vs CPWPT; SDWPT vs CDWPT) for both sexes and sides. For the ST, there was similarly no significant difference for all the measures for both sides and sexes. Only a paired parameter showed a strong correlation (C-MTJST vs CST). Finally, tenocyte distributions in the QT and in the ST were significantly higher than in the PT for the female. The male showed no significant difference in the tenocyte distribution across the tendons. Collagen distribution across the tendons was also similar in each sex. Based on the findings of this study, the ST seems to be the preferred graft for an ACL reconstruction. The presented morphometric data on the commonly used grafts for ACL will be useful for preoperative planning of ACL reconstruction surgery and may shed more light into the usability of each graft with respect to healing at the donor site and knee recovery in individuals.