Cartilage Strain Distributions Are Different Under the Same Load in the Central and Peripheral Tibial Plateau Regions.

There is increasing evidence that the regional spatial variations in the biological and mechanical properties of articular cartilage are an important consideration in the pathogenesis of knee osteoarthritis (OA) following kinematic changes at the knee due to joint destabilizing events (such as an anterior cruciate ligament (ACL) injury). Thus, given the sensitivity of chondrocytes to the mechanical environment, understanding the internal mechanical strains in knee articular cartilage under macroscopic loads is an important element in understanding knee OA. The purpose of this study was to test the hypothesis that cartilage from the central and peripheral regions of the tibial plateau has different internal strain distributions under the same applied load.

Macro-, micro- and ultrastructural investigation of how degeneration influences the response of cartilage to loading.

Articular cartilage functions as a load-bearing tissue by virtue of a functional coupling between its hydrated proteoglycan component and its zonally differentiated fibrillar network. How degeneration influences this relationship at the macro-, micro-, and ultrastructural levels is investigated in this study. Healthy bovine patellae (N=9) and patellae exhibiting varying degrees of degeneration (N=16) formed the basis of the study.

Knee kinematics, cartilage morphology, and osteoarthritis after ACL injury.

This review examines a mechanism for the initiation of osteoarthritis after anterior cruciate ligament (ACL) injury by considering the relationship between reported ambulatory changes after ACL injury, cartilage adaptation to load, and the association between cartilage loads during walking and regional variations in cartilage structure and biology. Taken together, these observations suggest that cartilage degeneration after ACL injury could be caused by a kinematic gait change that shifts ambulatory loading applied to cartilage. Such a shift may cause regions of cartilage to become newly loaded, be subjected to altered levels of compression and tension, or become unloaded.

Rotational changes at the knee after ACL injury cause cartilage thinning.

We examined the relationship between specific gait changes after anterior cruciate ligament injury and the progression of osteoarthritis at the knee. The study was done using a finite-element model derived from subject specific three-dimensional cartilage volumes created from magnetic resonance images. Cartilage thinning was predicted using an iterative algorithm based on the octahedral shear stress.

Finite element simulation of early creep and wear in total hip arthroplasty.

Polyethylene wear particulate has been implicated in osteolytic lesion development and may lead to implant loosening and revision surgery. Wear in total hip arthroplasty is frequently estimated from patient radiographs by measurement of penetration of the femoral head into the polyethylene liner. Penetration, however, is multi-factorial, and includes components of wear and deformation due to creep.