Currently, isometric exercises are widely used to increase muscle strength and endurance. They are also used in rehabilitation protocols for people with limited joint mobility after arthroplasty operations. The paper considers the effect of isometric exercises on the morpho-functional characteristics of muscle cells, cytokine secretion by muscle cells, blood circulation and mass transfer in muscle tissue, as well as on bone remodeling and repair. The existing protocols for early rehabilitation of patients after arthroplasty are not optimal and do not take into account the individual characteristics of patients. To develop effective methods of early rehabilitation of patients after arthroplasty, it is necessary to know the biophysical basis of the influence of isometric exercises on the regeneration of muscle and bone tissue.

Improving the effectiveness of early rehabilitation of elderly patients after hip arthroplasty remains an urgent task. The aim of the study was to evaluate the effectiveness of isometric exercises in early (2 weeks) rehabilitation of elderly patients after hip replacement using blood parameters. The randomized study included ten elderly patients in the control (n = 5) and experimental (n = 5) groups with isometric exercises and rehabilitation techniques that were performed daily from 1 to 12 days after total cement hip arthroplasty. The effectiveness of rehabilitation was assessed by the indices of muscle traumatization (myoglobin, creatine phosphokinase, aspartate aminotransferase, and lactate dehydrogenase concentrations) and systemic inflammation (erythrocyte sedimentation rate, CRP concentrations, and interleukins IL-6, IL-8, and IL-1β) in the blood of patients on the 12th day after surgery. The indices of muscle traumatization and the concentrations of C-reactive protein and leukocytes in blood, as well as the erythrocyte sedimentation rate did not reveal any significant difference between the groups of patients. The difference between the control and experimental groups in terms of restoration of interleukin IL-6, IL-8, and IL-1β concentrations in the blood to the normal range was statistically significant according to Fisher’s exact test (p = 0.042). In general, these results showed that additional isometric exercises provided more effective early rehabilitation of elderly patients after endoprosthesis in comparison with the standard set of exercises and that normalization of the concentration of proinflammatory interleukins, primarily IL-6 and IL-8, can be considered as an objective indicator in assessing the effectiveness of methods of early rehabilitation of elderly patients after hip arthroplasty.

Developing molecular methods for assessing the effectiveness of physical rehabilitation remains a pressing task. Our pilot study aimed to assess the utility of the transcriptome analysis of muscle biopsies in evaluating the efficacy of the isometric exercises (IEs) added to the standard protocol in the early rehabilitation of older patients during the initial two weeks post total hip arthroplasty (THA). Blood concentrations of total leukocytes, neutrophils, IL6, IL8, IL1β, myoglobin, etc. were measured, and transcriptome analysis of rectus femoris biopsies from the operated leg was performed before and after (1 and 12 days) THA in women aged 73–77 years. The additional IEs in the experimental rehabilitation group led to a significant acceleration in the recovery of IL6, IL8, and IL1β blood levels to the normal ranges compared to the control group, as confirmed by a Fisher’s exact test for this cytokine combination. The results of Gene Set Enrichment Analysis and Differentially Expressed Gene Analyses for the muscle biopsies point to accelerated resolution of inflammation, along with enhanced activation of genes associated with angiogenesis, lymphangiogenesis, vasodilation, and vasoconstriction in the experimental rehabilitation group compared to the control group. Thus, IL6, IL8, and IL1β blood levels can serve in combination as molecular indicators of the efficacy of early rehabilitation after THA, and transcriptome analysis of the rectus femoris biopsies of the operated leg allows for the revelation of the molecular indicators of regenerative processes in muscle tissue near the surgery area after THA.