MRI Arthroscopy Correlations: Ligaments of the Knee

Ultrasound With Stress for Assessing Injuries to the Medial and Lateral Collateral Ligaments of the Knee

Physical examination of knee ligament injuries often is considered subjective and imprecise as the result of various factors affecting its reliability. Magnetic resonance imaging is widely used but lacks information on ligament function and is costly. Stress radiography is commonly employed, but alternatives are sought because of radiation exposure and the need for a physician's presence during the procedure. Ultrasonography represents a noninvasive, rapid, and cost-effective method for assessing knee injuries. This Technical Note presents stress ultrasonography protocols for evaluating medial and lateral tibiofemoral openings in patients with posteromedial corner and/or posterolateral corner injuries. The ultrasonography examination parameters are detailed for both the medial collateral ligament and lateral collateral ligament evaluation. Studies have associated certain degrees of tibiofemoral opening with knee ligament injuries, aiding surgeons in surgical decision-making. Examination with stress ultrasonography offers a dynamic and reproducible method without adverse effects for patients, potentially expediting the diagnosis and treatment of multiligament knee injuries.

Anatomy and Biomechanics of the Posterior Cruciate Ligament and Their Surgical Implications

Knowledge and understanding of the complex anatomy and biomechanical function of the native posterior cruciate ligament (PCL) is vitally important when evaluating PCL injury and possible reconstruction. The PCL has important relationships with the anterior cruciate ligament, menisci, tibial spines, ligament of Humphrey, ligament of Wrisberg, and the posterior neurovascular structures. Through various experimental designs, the biomechanical role of the PCL has been elucidated. The PCL has its most well-defined role as a primary restraint/stabilizer to posterior stress and it seems this role is greatest at higher degrees of knee flexion. The natural history of high-grade deficiency leads to increased contact pressures and degeneration of both the medial and patellofemoral compartments. There is still considerable debate regarding whether high-level athletes can return to sport at the same level with conservative treatment of a high-grade PCL tear, and whether greater laxity in the knee correlates with decreased subjective and objective outcomes. Poor surgical outcomes after PCL reconstruction have been attributed to many factors, the most common of which include: additional intra-articular pathology, poor fixation methods, insufficient knowledge of PCL anatomy, improper tunnel placement, and poor surgical candidates.