Morphology of Intra-articular Structures and Histology of Menisci of Knee Joint.

Introduction: Menisci and cruciate ligaments are intra-articular structures of knee, and injury to these structures is common. Morphometric data gained in the study will help in analyzing the variations among humans and correlating it with the possibility, location, and type of injuries as well as better interpretation of structures during magnetic resonance imaging and arthroscopy which will further help in reconstructive surgeries of knee.

Materials and Methods: Width and thickness of the medial menisci (MM), lateral menisci (LM), and maximum length and width of anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were taken on twenty knees. Histological examination of menisci was done.

Results: Width of MM was 0.601-0.700 cm at anterior horn (AH) in 45% of cases, 1.000-1.500 cm at posterior horn (PH) in 60% of cases, and 1.000-1.500 cm at body in 30% of cases. Thickness of MM at AH (45%) and PH (40%) was 0.401-0.500 cm and at body (35%) was 0.501-0.600 cm. Width of LM at AH (35%) was 0.801-0.900 cm, at PH (45%) was 0.901-1.000 cm, and at body (35%) was 1.000-1.500 cm. Thickness of LM at AH (45%) was 0.301-0.400 cm, at PH (50%) was 0.401-0.500 cm, and at body (40%) was 0.601-0.700 cm. Length of ACL in maximum percentage of specimens (55%) was 3.01-3.50 cm. Width of ACL in 25% specimens were 0.801-0.900 cm and in another 25% specimens were 1.001-1.500 cm. Length of PCL in maximum percentage of specimens ( 50 %) was 3.51-4.00 cm. Width of PCL in 80 % of specimens was 1.001-1.500 cm. Histological examination of menisci showed fibrocartilage (outer two-thirds) and hyaline cartilage (inner one-third). Orientation of fibers was circumferential with intermingled radial fibers. Fibroblasts, chondrocytes, and unclassified cells were arranged as single, paired, or in rows along the direction of fibers except in hyalinized part. Blood vessels were present toward the peripheral part.

Conclusions: The maximum width of MM was at PH and for LM it was at the body. Maximum thickness was at the body for MM as well as LM. Width of PCL was more as compared to ACL.