Biomechanical analysis of ACL, PCL, and/or meniscus transection in Turkey: A potential large OA animal model

Osteoarthritis (OA) is a progressive disease characterized by cartilage degradation, subchondral bone remodeling, and osteophyte formation, leading to pain and functional decline. Animal models are crucial for studying injury mechanisms, biomechanical changes, and potential OA treatment. The bipedal turkey model shows promise as a valuable large-animal model due to its arthroscopic feasibility and relevance to traumatic knee injury research. However, the underlying kinematic mechanisms remain poorly understood. This study aimed to elucidate these mechanisms through biomechanical analysis of the turkey knee's response to transection of its crucial static stabilizing structures, including the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and medial meniscus (MM) at flexion angles of 60°, 90°, and 120°. Kinematic measurements, including anterior-posterior displacement and internal-external rotation, were measured pre- and post-arthroscopic transections performed in randomized order. Due to joint subluxation following ACL transection, testing was conducted both from the knee's native and subluxed positions. Results demonstrated the largest kinematic changes at 60° flexion. ACL transection substantially increased anterior translation, often leading to anterior tibial subluxation. Testing from the native position showed significant anterior displacement as the knee transitioned to a subluxed position. In contrast, testing from the subluxed position exhibited increased posterior translation as the tibia moved toward the native position. These findings highlight that dynamic tibial subluxation during gait may alter contact mechanics between the tibia and femur, thereby promoting cartilage degeneration and early-onset OA. The turkey knee model demonstrates clinical relevance for studying PTOA mechanisms and testing therapeutic interventions.