Intra-articular ganglia and cysts of the knee joint are rare and mostly incidental findings in MRI and arthroscopy. During a period of 15 years, nearly 8000 knees were arthroscopically examined. In total, 85 intra-articular soft tissue masses were found within the knee cavity. Of these, 76 were incidental and asymptomatic findings in arthroscopy performed for treatment of osteoarthritic symptoms. Several repeated minor knee traumata were reported in this group but no histories of serious traumatic events. Nine ganglion cysts were obviously solely responsible for the intermittent or chronic non-specific knee discomfort, and classified as symptomatic. There were no histories of previous injury to the knees, no clinical signs of instabilities or meniscal and femoropatellar pathologies, and no associated further intra-articular lesions in arthroscopy. Forty-nine cystic masses originated from the ACL, 16 from the PCL, 12 from the anterior (eight medial, four lateral) and three from the posterior horn of the menisci (two medial, one lateral). Three were located in the infrapatellar fat pad, one arose from a medial plica and one from a subchondral bone cyst. All ganglion cysts were successfully resected or excised using arthroscopic technique. A review of the literature is given and compared with the findings and data of this study.

This study examined ten human adult cadaveric knees to dissect the popliteus muscle-tendon unit (PMTU), including its numerous attachments to other posterior and posterolateral structures, and to determine the effect of tensioning the PMTU on the internal and external rotation, total rotational arcs, and neutral tibial rotation in full extension and 30 degrees, 60 degrees, and 90 degrees of knee flexion. The junction between the popliteus tendon and the fibular head commonly described as the popliteofibular ligament became lax in internal and tense in external tibial rotation. The internal and external rotational arcs increased gradually between extension and 90 degrees of flexion. Tensioning the PMTU resulted in a statistically highly significant internal tibial rotation with decreased internal and increased rotational arcs. The anatomical findings and functional data indicate that the PMTU is an important structure maintaining dorsolateral stability, stabilizing the lateral meniscus, and balancing the neutral tibial rotation.

This study evaluated the correlation between the number of transected posterolateral structures (PLS) and the grade of posterolateral rotational instability, determined the effect of the popliteus muscle-tendon unit on the tibial rotation, and examined the effect of an isolated posterior cruciate ligament (PCL) and combined PCL-PLS reconstruction on knee stability. Sectioning the popliteofibular and lateral collateral ligaments both caused an increase in tibial external rotation. Cutting the PT resulted in a statistically highly significant excessive external rotation and externally shifted neutral position of the tibia over the full range of motion. Tensioning the popliteus muscle-tendon unit led to a statistically highly significant internally shifted neutral tibial rotation and a decreased internal and an increased external rotation without affecting the total rotational arcs. The isolated PCL reconstruction did not affect the external rotation, whereas the combined PCL-PLS reconstruction reset the knee to nearly physiological laxity patterns.

No abstract

No abstract