Morphologic and Morphometric Evaluation of Oblique Popliteal Ligament - A Clinico-Anatomical Study

Introduction: The oblique popliteal ligament (OPL), chief posterior support of the knee, is an extension of the semimembranosus (SM) tendon and runs superolaterally to the lateral femoral condyle. Due to variations and immense functional value of the OPL, the present study was undertaken to explore the OPL morphology and morphometry. Materials and methods:Thirty cadaveric lower limbs were dissected to observe the OPL in the floor of the popliteal fossa, and its general shape, number of bands and extensions were noted. The morphometry was done using digital callipers in which the length of the upper and lower margins as well as the width of the OPL at the medial and lateral attachments were measured. The width of bands and extensions were also recorded. The mean and standard deviation (SD) of all parameters have been also calculated. Results:The morphological types of the OPL were categorized into four types, which were found in 40%, 50%, 6.6% and 3.3% of specimens, respectively. Types 1 and 2 OPL were band like. Type 1 showed an accessory upper band and type 2, a broad medial attachment. Type 3 was cord like, whereas type 4 was fan like and showed two upper bands. The mean length (upper), length (lower), width of the SM tendon expansion, width at attachment to the medial femoral condyle and width at the lateral attachment were 33.4 mm, 38.41 mm, 8.58 mm, 12.46 mm and 21.42 mm, respectively. Conclusion:The different morphological types of OPL may produce minor alterations in the stability of the knee, especially in trauma. The anatomical knowledge of OPL and its extensions is mandatory for knee surgery in all patients to avoid postoperative complications.