Muscle Strength and Function in Knee Osteoarthritis

Knee osteoarthritis is characterised not only by degeneration of articular cartilage but also by profound alterations in periarticular muscle health. Among these, the quadriceps muscle group assumes particular importance for joint stability, shock absorption and functional mobility. In osteoarthritis, chronic joint inflammation, pain and altered joint mechanics trigger arthrogenic muscle inhibition, leading to marked quadriceps weakness, fibre atrophy and neuromuscular junction remodelling. These changes contribute to reduced proprioceptive acuity, impaired gait and an elevated risk of falls. At a molecular level, inflammatory cytokines and proteolytic pathways—mediated by factors such as muscle RING-finger protein-1—accelerate muscle protein breakdown, while diminished satellite cell activity compromises regeneration. Hamstring and calf muscles also undergo adaptive changes that further destabilise the knee. Restoring muscle mass and function is therefore a cornerstone of holistic management, with exercise prescription, neuromuscular re-education and emerging biological interventions all striving to interrupt the cycle of weakness and joint deterioration. This interplay between muscle biology and joint mechanics underlines the global importance of integrated therapeutic strategies to preserve independence and quality of life in individuals with knee osteoarthritis.

Research from Nature Portfolio

One foundational investigation employed an anterior cruciate ligament transection model in rats to explore muscle and neuromuscular junction adaptations in knee osteoarthritis. After eight weeks, researchers observed significant atrophy of the quadriceps and tibialis anterior muscles, accompanied by increased expression of atrophy-related genes and proteins, including muscle RING-finger protein-1. Concurrent remodelling of neuromuscular junction morphology and shifts in acetylcholine receptor subunit composition suggested that synaptic instability contributes to diminished muscle function. The study highlights inflammation-driven alterations at both the cellular and synaptic levels, pointing to potential targets for therapies aimed at preserving muscle integrity and improving functional outcomes in osteoarthritis.

Muscle Strength and Function in Knee Osteoarthritis publication trend

The graph below shows the total number of articles in muscle strength and function in knee osteoarthritis across all publications each year (not limited to Nature Index journals).

Technical terms

Quadriceps: The large muscle group at the front of the thigh responsible for knee extension and dynamic stabilisation.

Arthrogenic muscle inhibition: A reflexive reduction in muscle activation resulting from joint pain or damage.

Neuromuscular junction (NMJ): The synapse where a motor neuron communicates with a muscle fibre to initiate contraction.

Satellite cell: A specialised muscle stem cell that governs post-injury repair and muscle growth.

Muscle RING-finger protein-1 (MuRF-1): An E3 ubiquitin ligase that marks muscle proteins for degradation during atrophy.

References

1. Quadriceps recovery and pain relief in knee osteoarthritis rats by cog polydioxanone filament insertion. Regenerative Biomaterials (2024).
2. Assessment of the Impact of Physical Activity on the Musculoskeletal System in Early Degenerative Knee Joint Lesions in an Animal Model. International Journal of Molecular Sciences (2023).
3. Inter-rater reliability and test-retest reliability of the foot posture index (FPI-6) for assessing static foot posture in elderly female patients with knee osteoarthritis and its association with quadriceps muscle tone and stiffness. Frontiers in Bioengineering and Biotechnology (2024).
4. Knee osteoarthritis induces atrophy and neuromuscular junction remodeling in the quadriceps and tibialis anterior muscles of rats. Scientific Reports (2019).
5. Skeletal Muscle Wasting and Its Relationship With Osteoarthritis: a Mini-Review of Mechanisms and Current Interventions. Current Rheumatology Reports (2019).
6. The effects of pain on quadriceps strength, joint proprioception and dynamic balance among women aged 65 to 75 years with knee osteoarthritis. BMC Geriatrics (2018).