Roentgen Examination of the Intercondyloid Fossa of the Knee Joint

Abstract

FROM a clinical standpoint, there are a certain number of cases which present definite intra-articular pathology of the knee joint, in which the roentgen films taken in the usual manner give little or no aid to the clinician. Thus, a view for the visualization of the intercondyloid space and the posterior compartment of the knee joint is essential; the idea was first suggested by Béclère, and later by Frik, in 1932. There are a number of scattered reports in the foreign literature, but we were unable to find any report in the American literature. The value of this view for the interpretation of intercondyloid pathology is so beautifully illustrated that it warrants its publication. The anatomy of the intercondyloid fossa and its contents is an aid in understanding the value of this view for visualization of its contents in diseases. The lower third of the femur has two condyles which are separated behind by the intercondyloid fossa, this fossa being tilted at an angle of 60 degrees. Anteriorly, the lateral condyle is wider and more prominent, while the medial condyle is narrower and longer to compensate for the obliquity of the shaft. When the femur is in the natural position, the inferior surfaces of the condyles are on the same plane and almost parallel for articulation with the upper surfaces on the head of the tibia. The two condyles are continuous in front, forming a smooth trochlear surface for articulation with the patella. The opposed surfaces of the two condyles form the boundaries of the intercondylar fossa and give attachment to the crucial ligaments. The posterior crucial ligament is attached to the fore part of the lateral surface of the medial condyle, and the anterior crucial ligament to the back part of the medial surface of the lateral condyle (Morris). The synovial membrane also projects into the joint and is occupied by fat, which serves as a padding to fill the spaces. The chief of these processes—patellar synovial fold, or the ligamentum mucosum—arises from the infrapatella fat mass. This so-called ligament is the central portion of the large process of the synovial membrane, of which the alar folds form the free margins. It extends from the fatty mass below the patella backward, and upward to the intercondyloid notch of the femur, where it is attached in front of the anterior crucial and lateral to the posterior crucial ligament. This ligament becomes tense in flexion and serves to keep the pad in position when there is positive pressure in the joint (Fisher). A roentgen film taken in the usual manner does not permit the intercondyloid space to be seen, because the anterior portion of the intercondyloid part of the femur is superimposed upon this space. Many times the spines of the tibia are partly covered by this portion of bone.