Tibiofemoral Joint Contact During the Loading Response Phase of Gait in Individuals With Concurrent Knee Osteoarthritis and Complaints of Joint Instability

Knee osteoarthritis (OA) is one of the most prevalent chronic conditions affecting older adults and commonly leads to pain and functional limitations. Many individuals with knee OA also report episodes of knee instability, which has been shown to adversely affect their ability to perform weight-bearing functional tasks. [1] Recently it was reported that individuals with knee OA and reports of joint instability demonstrate significant reductions in their sagittal and transverse plane rotational knee joint motion. [2] It is conceivable that the decreased rotational joint motion may represent a compensatory attempt to avoid pain and/or to stabilize an unstable knee joint. However, this movement strategy may be problematic in the long term as it could lead to increased compressive loading and a reduction of shock absorption capabilities. Since abnormal rotation is associated with altered joint contact position [3], and the internal/external rotation axis in the normal knee is located on the medial side [4,5], this patient population may exhibit a decreased contact path length in the lateral compartment during the loading response phase of gait. The combination of a reduced contact path length and cartilage loss could in turn lead to a decreased dynamic joint space [6] and concentration of joint stresses responsible for disease progression. Therefore, the objectives of this work were to 1) compare the tibiofemoral joint contact path length and dynamic joint space in the medial and lateral compartments during the loading response phase of gait in individuals with knee OA and complaints of joint instability to a healthy control group and 2) investigate the relationship between these parameters.