Knee Capsule Anatomy: An MR Imaging and Cadaveric Study

Abstract

This research focuses on the anatomical insertion of the synovial capsule around the knee. The attachments of the capsule were measured in 50 knee MR imaging studies with large intraarticular effusion. Corresponding measurements were performed in 20 fresh frozen cadaveric specimens, for validation. Femoral and tibial capsular reflections were defined as the distances between the attachment sites of the capsule and the femoral or tibial joint line and they were recorded in three coronal planes (anterior/middle/posterior). On MR imaging, the lateral/medial femoral capsular reflection mean values were 6.5/4.57 cm, 2.74/1.74 cm and 1.52/1.99 cm in the anterior, middle and posterior plane, respectively. MR imaging-based measurements did not differ significantly compared to corresponding cadaveric measurements. The mean values of the lateral/medial tibial capsular reflection on MR imaging were 0.09/0.11 cm, 0.34/0.26 cm and 0.62/0.34 cm in the anterior, middle and posterior plane, respectively. On cadaveric dissection, the maximum mean value was 1.45 cm, measured on the lateral side of the anterior plane. Apart from the lateral aspect of the posterior plane, MR imaging measurements were significantly lower, compared to the corresponding cadaveric measurements. The greatest femoral and tibial capsular reflections were found on the anterior and lateral side of the anterior plane. MR imaging appears to underestimate the distal extent of the knee capsule. Anatomical details of the knee capsule should be considered for safe insertion of external fixator pins.

Quadriceps Muscle and Medial Retinaculum Combinate Effects on Patellar Instability during Knee Flexion

“…The knee joint is a highly mobile joint made up of the tibial-femoral and patellofemoral joints [3], the first consists of two geometrically incongruent bone segments, the femur, and the tibia, which are joined by the condyles of the femur and the tibial plateau, between which the menisci are located [4]. These two bony ends are covered by a strong fibrous capsule which holds them together in synergy with the action of the ligaments, which, combined with the geometry, restrict movement [5,6]. On the other hand, the patellofemoral joint is composed of the patella and the trochlear surface, which are morphologically related, i.e., the patella has an optimised surface for sliding over the femur, which in turn forms a groove that acts as a track for the patella [7].…”