The "oblique popliteal ligament": a macro- and microanalysis to determine if it is a ligament or a tendon.

Introduction. This study investigated the importance of the "oblique popliteal ligament" (OPL), and challenges its alleged ligament status. The currently named OPL is indigenous to the distal semimembranosus (SMT); therefore, by definition is not a ligament inserting from bone to bone. Clinically, a muscle-tendon unit is different then a ligament regarding proprioception and surgery. Methods. Literature search was conducted on texts, journals and websites regarding the formation of the OPL. Dissection of 70 knees included macro analysis, harvesting OPL, distal SMT and LCL samples and performing immunohistochemistry to 16 knees with antibody staining to the OPL, distal SMT and LCL. Results. All but one text claimed the OPL receives fibers from SMT. Macro dissection of 70 knees revealed the OPL forming from the distal SMT (100%). Microanalysis of OPL, distal SMT and LCL samples from 16 knees demonstrated expression of nervous tissue within selected samples. Discussion. No journals or texts have hypothesized that the OPL is a tendon. Clinically it is important we know the type of tissue for purposes of maximizing rehabilitation and surgical techniques. Conclusion. This study suggests the OPL be considered the oblique popliteal tendon as a result of the macro and micro evidence revealed.