Quantification and comparison of tenocyte distribution and collagen content in the commonly used autografts for anterior cruciate ligament reconstruction

Anterior cruciate ligament is a commonly damaged ligament of the knee. Reconstruction of this ligament usually entails the use of graft harvested from the same subject (i.e., autografts). Several tendons, for example quadriceps, patellar or semitendinosus tendon can be used as an autograft. The composition of the tendons is similar to the anterior cruciate ligament but there is no data that directly compares the compositions of the quadriceps, patellar and semitendinosus tendons. This study quantified and compared the tenocyte distribution and collagen content of these tendons from cadavers of South Africans of European Ancestry. The tenocyte distribution and collagen content were assessed using the ImageJ software. The results showed similarities in the collagen content across the tendons in both sexes (P>0.05). The tenocyte distribution was significantly higher in the quadriceps (P=0.019) or semitendinosus (P=0.016) tendon than in the patellar tendon in the female but no difference was seen in the male (P=0.872). This shows that a large harvestable area may not be directly associated with a more abundant collagen content or tenocyte distribution in the tendon. However, sex-specific tenocyte distribution is an important observation that underpins the possible influence of underlying biological factors on the composition of each tendon and this requires further investigations. In all, this study will contribute to knowledge and assist orthopaedic surgeons in making an informed decision on the choice of graft.