People who undergo knee replacement surgery may be at increased risk of falls both prior to and 4 months following their surgery, primarily due to deficits in knee extension strength and lower limb proprioception. Therefore, interventions to reduce the risk of falls should be implemented early after the surgery.

BackgroundFoot posture has long been considered to contribute to the development of lower limb musculoskeletal conditions as it may alter the mechanical alignment and dynamic function of the lower limb. This study compared foot posture in people with and without medial compartment knee osteoarthritis (OA) using a range of clinical foot measures. The reliability of the foot measures was also assessed.MethodsThe foot posture of 32 patients with clinically and radiographically-confirmed OA predominantly in the medial compartment of the knee and 28 asymptomatic age-matched healthy controls was investigated using the foot posture index (FPI), vertical navicular height and drop, and the arch index. Independent t tests and effect size (Cohen's d) were used to investigate the differences between the groups in the foot posture measurements.ResultsSignificant differences were found between the control and the knee OA groups in relation to the FPI (1.35 ± 1.43 vs. 2.46 ± 2.18, p = 0.02; d = 0.61, medium effect size), navicular drop (0.02 ± 0.01 vs. 0.03 ± 0.01, p = 0.01; d = 1.02, large effect size) and the arch index (0.22 ± 0.04 vs. 0.26 ± 0.04, p = 0.04; d = 1.02, large effect size). No significant difference was found for vertical navicular height (0.24 ± 0.03 vs. 0.23 ± 0.03, p = 0.54; d = 0.04, negligible effect size).ConclusionPeople with medial compartment knee OA exhibit a more pronated foot type compared to controls. It is therefore recommended that the assessment of patients with knee OA in clinical practice should include simple foot measures, and that the potential influence of foot structure and function on the efficacy of foot orthoses in the management of medial compartment knee OA be further investigated.

Objective. Increased inflammation and pain are inseparable parts of knee osteoarthritis (OA) that may lead to disuse of the affected limb. The aim of this study was to examine the effects of knee OA on inflammationand atrophy-related genes and proteins in the vastus lateralis muscle of patients with knee OA.Methods. Nineteen patients with knee OA and 14 asymptomatic control subjects matched for age and body mass index underwent strength measurements and a muscle biopsy. Results. Knee OA resulted in greater levels of IL-6 protein (34%; P ‫؍‬ 0.002). The levels of inflammatory kinases, including STAT-3 (187%; P ‫؍‬ 0.002), p65 NF-B (156%; P ‫؍‬ 0.002), and JNK1 (179%; P ‫؍‬ 0.027), were also elevated. Furthermore, elevated expression of gene transcripts encoding MCP-1 (28%; P ‫؍‬ 0.023), TNF␣ (85%; P < 0.001), and SOCS-3 (38%; P ‫؍‬ 0.055) was observed in patients with knee OA compared with control subjects. Patients with knee OA had reduced muscle strength compared with control subjects Conclusion. Gene expression and the protein abundance of numerous muscle markers of inflammation and atrophy were elevated in patients with knee OA, and the increase in muscle inflammation was associated with a reduction in muscle strength. Given the role inflammation markers may play in muscle strength and atrophy, further studies are needed to investigate the effect of exercise intervention on skeletal muscle inflammation.

Australian New Zealand Clinical Trials Registry, www.anzctr.org.au/, ACTRN12608000116325.