Neuromuscular Adaptations Related to Medial Knee Osteoarthritis and Influence of Unloader Braces on Neuromuscular Activity in Knee Osteoarthritis Subjects-A Systematic Review.

ABSTRACT: Unloader braces are a treatment modality for medial compartment knee osteoarthritis. The functional mechanisms involved are not yet fully understood. Therefore, this two-part systematic review examines the following research questions: How is muscle activation altered by medial compartment knee osteoarthritis, and do medial tibio-femoral compartment unloader braces alter muscle activation? If so, could this alteration be part of the unloading mechanism by affecting the altered muscle activity in medial compartment knee osteoarthritis?A systematic literature search was conducted using PubMed, LIVIVO, Web of Science, Google Scholar, and CENTRAL for articles published until August 2023. The first systematic review, examining neuromuscular alterations, identified 703 articles, with a final inclusion of 20. The second systematic review, which evaluated the neuromuscular effects of unloader braces, identified 123 articles with the final inclusion of 3. Individuals with medial compartment knee osteoarthritis demonstrated increased activity and co-contraction of the periarticular knee muscles, whereas medial tibio-femoral compartment unloader braces seemed to reduce activity and co-contraction. In contrast to the belief that unloader braces result in muscle weakness as they decrease muscle activity and co-contraction, our limited insights indicate that they rather might reduce the pathological increase. This may result in joint load reduction due to lower compressive forces. However, further investigation is required.

Combinatory effects of phytoestrogens and exercise on body fat mass and lipid metabolism in ovariectomized female rats.

The purpose of this study was to investigate the combinatory effects of an isoflavone (ISO)-rich diet and exercise on fat mass and lipid metabolism in ovariectomized (OVX) rats. Therefore the female Wistar rats were sedentary, performed an intense treadmill uphill running, received ISOs, or a combination of ISOs and running after ovariectomy. The exercise reduced visceral fat mass, adipocyte size and serum leptin in Sham animals and antagonized the increases of these parameters induced by OVX. ISOs reduced OVX induced increase of serum leptin. The combination of training and ISOs was most effective in reducing serum triglyceride levels. In OVX rats the training stimulated the expression of genes associated with fatty acid synthesis (SREBP-1c and FAS) in adipose tissue, soleus muscle, liver and genes associated with fatty acid oxidation (PPARδ and PGC-1α) in adipose tissue. ISOs stimulated the expression of SREBP-1c and FAS in soleus muscle and PGC-1α in adipose tissue, whereas suppressed hepatic SREBP-1c and FAS expression. Strong additive effects of ISOs combined with the training were observed for PPARδ and PGC-1α expressions in soleus muscle. In conclusion our results demonstrate that both the training and ISOs affect fat mass and fatty acid metabolism in OVX rats. The training seems to have a higher impact than ISO exposure in regulating gene expression in adipose tissue. However, the strongest effects for several of the addressed parameters could be observed in the combination group especially in the soleus muscle. Therefore a combination of training and an ISO-rich diet may have beneficial effects on fatty acid metabolism and could be a concept for the prevention of obesity in postmenopausal females.