An anatomical and histological study of human meniscal horn bony insertions and peri-meniscal attachments as a basis for meniscal transplantation

Background Allograft meniscal transplantation is an increasingly popular treatment option for the symptomatic young patients with meniscus deficiency. However, many questions still surround it. In this research, we studied the anatomical location and histological structure of human meniscal horn bony insertions and to observe the anatomical morphology and histomorphology of peri-meniscal attachments based on meniscal allograft transplantation.Methods Twenty-two fresh-frozen adult cadaver knees were dissected. The locations of meniscal anterior and posterior horn bony insertions to tibia were measured. The anatomical morphology of peri-meniscal attachments was observed and the histological structure of meniscal horn bony insertions and peri-meniscal attachment were studied by HE staining.Results The anterior horn bony insertion of medial meniscus was (9.19±1.83) mm inferior to the corresponding anterior border of tibial plateau, and (7.81±2.25) mm lateral to the axial line of the medial intercondylar eminence. The posterior horn bony insertion of medial meniscus was in the posterior intercondylar fossa of tibia, located between the anterior fibers of the posterior cruciate ligament (PCL) tibial insertion and anterior border of the tibial posterior intercondylar fossa,and was (5.05±1.18) mm lateral to the axial line of the medial intercondylar eminence. The distance between anterior and posterior horn bony insertions of the lateral meniscus was (13.68±2.19) mm. Anterior horn bony insertion of the lateral meniscus was (3.99±1.27) mm medial to the axial line of the lateral intercondylar eminence, and the posterior horn bony insertion of the lateral meniscus was (5.80±1.36) mm medial to the axial line of the lateral intercondylar eminence. Except for the meniscal horn bony insertions, which is the typical enthesis, we call the attachment of the other parts of menisci as 'peri-meniscal attachment'. The morphological and histological study showed that the main peri-meniscal attachment was the meniscotibial ligament, through which the meniscus attached to the tibia with enthesis structure, and there was only loose connective tissue between menisci and capsule.Conclusions In meniscal allograft transplantation, the traditional meniscal size-matching method which take medial and lateral intercondylar eminences as references is not as accurate as expected. Attention should be taken to locate both anterior and posterior horn tunnels of medial meniscal allograft inferior to the tibia plateau, and to locate anterior and posterior horn tunnels of lateral meniscus close enough (mean 13.68 mm). The best way to reconstruct the peri-meniscal attachment is to suture the allograft to the preserved outer remnant of the original meniscus.