Description

Patients with end stage OA often adopt a sedentary lifestyle causing mobility and functionality decline to avoid joint pain and stiffness. This dysfunctions a series of antioxidant response cascades which eventually leads to muscle atrophy of the knee. Notably, muscle atrophy and weakness (i.e. sarcopenia) often accompanies with OA. However the relationship between these symptoms and OA remains undefined and no strong consensus have been made thus far. Our ongoing longitudinal study on muscle strength and functionality which investigates the prevalence of sarcopenia in end stage OA patient's pre and post operation (Total Knee Replacement) have reflected that 24% with severe knee OA patients also suffered sarcopenia. In addition, these patients also showed a much slower recovery and longer length of stay in hospital after undergoing surgical operation.

The effect of clinical sarcopenia affects our locomotion system in the aging population. Weakness in patients and decline in muscle strength results in significant functional impairment are often seen in the cohort, leading to fragility, falls, fractures and disability.

Many authors have tried to explain the pathophysiology of sarcopenia in an attempt to link the disorder to a molecular or biochemical level in numerous literature. Satellite cells (a myogenic stem cell), Insulin like growth factor 1 (IGF-1) (an important mediator of muscle growth and regeneration affecting muscle function) and fast twitch muscle fibres are three major molecular composites that have been widely studied. Evidence have suggested the close relationship between them and muscle atrophy and weakness. However, these studies have either shown the results from an animal standpoint or they lack specificity and further research is necessary to confirm their role in patients suffering from sarcopenia.

Attempts have also been made to discover the most effective intervention to treat or even eliminate the chances of sarcopenia. Among these studies resistance exercises have been documented the most.

Evidence showed that progressive resistance and aerobic exercises are most beneficial for the prevention and treatment of sarcopenia. Resistant training that such as lifting weights, strength resistance bands, resistance machines has shown to improve protein synthesis in skeletal muscle cells leading to better muscle strength and mass, leading to muscle hypertrophy and promotes muscle power. Our previous knowledge transfer study on developing an aerobic exercise (i.e. Tai Chi Exercise) for end stage OA patients also showed similar positive effects in subjects, decreasing their pain and stiffness symptoms and limitations in physical activity. Though resistance exercise showed promising effects, are safe and strongly advised interventions based on documented and our previous study, the elderly populations often accompanies with other physical symptoms (such as back pain) and diminished fine motor skills that may limit their range of movement in these exercise regimes. In addition, resistive exercises are extremely technical and is essential to execute with proper form to avoid further injury; hence these exercises are unable to perform safely alone at home, making the intervention less autonomous.

Vibration therapy is a noninvasive biophysical modality and has been demonstrated in a number of studies showing multiple positive effects in terms of postural control, balancing ability, circulation and most importantly muscle strength. Two of our previous studies investigated the long term effects on muscle performance and bone quality in using low-magnitude high frequency vibration. Though the results showed that the treatment is an effective method in fall prevention by improving on both frontiers, these two studies' main subject focuses were on the elderly population as a whole. A study pivoting on subjects with co-existing diagnosis of sarcopenia and OA is crucial to investigate the effectiveness of this therapy method. Limited studies have shown positive effects of vibration therapy on osteoarthritis, however, these studies were limited to a single gender (i.e. females) or contained subject recruitment bias or assessment period of less than 6 months. A randomized control trial with a longer assessment period is essential to investigate the true effects of vibration therapy on knee OA patients.