PubMed Health⌕ Search

Biomedical subjects

Karin Ullrich

Publications and source records attributed to Karin Ullrich.

3 recordsLinked to original sources

Posterolateral aspect and stability of the knee joint. I. Anatomy and function of the popliteus muscle-tendon unit: an anatomical and biomechanical 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.

Adult↗

Posterolateral aspect and stability of the knee joint. II. Posterolateral instability and effect of isolated and combined posterolateral reconstruction on knee stability: a biomechanical study.

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.

Adult↗