An Assessment of Selected Sensorimotor Parameters and Muscle Performance in Hand Osteoarthritis for the Development of Treatment
Magni, Nicoló Edoardo
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Symptomatic hand osteoarthritis (OA) affects twenty percent of people over the age of 70. Its socioeconomic burden is increasing and despite severe repercussions on people’s quality of life, it has not received as much scientific attention as OA at other joints such as the knee and hip. The need for effective conservative interventions for hand OA has been suggested by several authors. Moreover, in light of recent research at other joints, it is important to assess sensorimotor and muscle impairments and their relation to function to determine the primary needs of a conservative program of rehabilitation. The first study compared selected measures of sensorimotor and muscle performance between people with hand OA and healthy controls. Furthermore, the relationship between these measures and function was assessed. People with hand OA were slower and less accurate in a hand left/right discrimination task and experienced neglect-like symptoms more frequently, suggesting they had a disrupted working body schema. However, no association was found between left/right discrimination performance and measures of hand function. While grip endurance was not different between groups, a significant loss of grip strength and a moderate relationship with self-reported function was identified in people with hand OA. We therefore hypothesised that improving grip strength may have beneficial effects in people with hand OA. To test this hypothesis, we completed a review and meta-analysis of research papers assessing the effectiveness of resistance training interventions on grip strength, pain and function in people with hand OA (Study two). Five studies with 350 participants were included. The findings showed no improvements in grip strength or function and limited effects on joint pain. However, it was apparent that most studies utilised exercise regimes considered inadequate to induce strength changes. In some studies, fear of pain exacerbations or doing further damage to the affected joints led researchers to limit load during the prescribed exercise regimes. The findings suggested that a low intensity exercise alternative may be beneficial to improve muscle strength and function in people with hand OA, while reducing the risk of pain exacerbations and attenuating joint compressive forces. After a subsequent search of the literature for low load strengthening programs, blood flow restriction training (BFR) appeared to be a viable treatment. This intervention has been shown to improve muscle strength and size in young, healthy people while utilising low exercise intensities. It was unclear however, if it was effective and safe in older people or individuals undergoing a period of disuse, as is common in OA. We therefore completed a systematic review and meta-analysis on this topic (Study three). Twenty-four studies, including a total of 485 individuals, were included. Findings suggested that BFR alone decreases the magnitude of strength loss associated with disuse. Furthermore, BFR training was found to be effective in improving strength and muscle size compared to matched low intensity exercise without BFR or a no intervention control. No difference was shown in treatment effects when comparing BFR to traditional high intensity strength training and there were few side effects associated with BFR. Thus, study four assessed the feasibility of BFR training in people with hand OA and compared training effects to a traditional high intensity strength training program (HIT). A six-week intervention was trialled and feasibility issues regarding recruitment potential were identified. These included regional differences in recruitment as well as potential for greater involvement of surgeons in the recruitment process. In patients who joined the study, compliance with treatment was good in both groups and after six weeks of training, pre-exercise joint pain reduced significantly. Both BFR and HIT rarely led to acute exacerbations in joint pain. Pinch strength improved significantly in both groups, while grip strength improved significantly in the BFR group only. The findings from this thesis suggest that people with hand OA present with both sensorimotor and muscle impairments but only grip strength was moderately associated with self-reported function. Both BFR and HIT appear effective in improving muscle strength and do not result in frequent pain exacerbations, with an overall decrease in pre-exercise joint pain intensity over the six-week training period, despite a progressive increase in training volume. Thus, in the future, an appropriately powered randomised controlled trial appears indicated and feasible, although additional strategies may be required to facilitate recruitment. Finally, although not explored in depth in this thesis, findings from study one suggest it is possible that interventions aiming at improving sensorimotor function may reduce symptoms and/or improve functional performance in people with hand OA. However, further research is required to explore these alternative treatment options.