Muscle atrophy in osteoarthritis: clinical features, pathological changes, underlying mechanisms, and exercise-based interventions

Background

Osteoarthritis (OA) is a common degenerative disease with cartilage injury as the core pathological phenotype, which has become the leading cause of disability in the elderly. Skeletal muscle is an important organ to maintain the structure and motor function of joints, which is highly related to OA progress. Patients with OA typically exhibit abnormalities in the skeletal muscles surrounding the joints, such as reduced muscle mass and strength. We refer to this condition as OA-related muscle atrophy (hereafter referred to as OAMA). The mechanisms of OAMA are multifactorial and unclear.

Methods

In this narrative review, we summarized relevant research progress of OAMA (i) to review the changes in skeletal muscle of patients with OA, (ii) to review the underlying biological mechanisms of OAMA, (iii) to review the effects of skeletal muscle on OA, and (iv) to provide perspectives on current and potential strategies of OA clinical treatment based on skeletal muscle, especially exercise training.

Results

OAMA may lead to the destruction of joint stability and cartilage homeostasis and then promote the occurrence and development of OA. Clinical manifestations of OAMA are a decline in muscle mass and strength and an abnormal movement pattern. The underlying biological mechanisms of OAMA include chronic inflammation, oxidative stress, ion metabolism, glycolipid metabolism, and epigenetics. The effects of skeletal muscle on OA are skeletal muscle-mediated cartilage damage via biomechanics, muscle-derived secretions, and muscle-derived stem cells.

Conclusions

More preclinical and clinical studies are imperative to study the mechanisms of OAMA and develop potential strategies. We hope that more studies can focus on the skeletal muscle during the OA process, which will be beneficial for delaying OA progression and improving the motor function of OA patients in the future.