VITAMIN D STATUS AND BONE TURNOVER MARKERS AS PREDICTORS OF FUNCTIONAL RECOVERY AFTER TOTAL HIP ARTHROPLASTY

Total hip arthroplasty contributes to pain reduction and restoration of motor activity; however, the rate of postoperative rehabilitation varies considerably among patients. Vitamin D status and the characteristics of bone remodeling are among the potential factors determining functional outcomes. Objective: to evaluate the clinical and laboratory significance of 25-hydroxyvitamin D, parathyroid hormone, and bone turnover markers in predicting func­tional recovery after total hip arthroplasty. Materials and methods. This prospective study included 75 patients aged 40–80 years who underwent primary total hip arthroplasty. Serum concentrations of 25(OH)D, parathyroid hormone, N-terminal propeptide of type I procollagen, and β-CrossLaps were measured. According to baseline 25(OH)D levels, the patients were divided into a vitamin D insufficiency or deficiency group with levels below 30 ng/mL (n=49) and a sufficient vitamin D status group with levels of 30 ng/mL or higher (n=26). Clinical and functional assessments were performed during the early postoperative period and at 1 and 3 months using the visual analogue scale for pain, Harris Hip Score, WOMAC index, six-minute walk test, Timed Up and Go test, hip flexion range of motion, and muscle strength assessment of the operated limb. Results. The overall sample demonstrated consistent improvement in clin­ical and functional parameters. Pain intensity decreased from 4.3±1.0 to 1.9±0.7 points, the Harris Hip Score increased from 61.4±7.9 to 83.9±7.2 points, and the WOMAC index decreased from 56.8±8.7 to 31.4±6.9 points. The six-minute walking distance increased from 186.5±42.3 to 356.8±54.2 m, while the Timed Up and Go test completion time decreased from 21.4±4.6 to 12.3±2.6 s. At 3 months, patients with 25(OH)D levels below 30 ng/mL had more severe pain, higher WOMAC scores, and lower Harris Hip Scores, six-minute walking distances, ranges of motion, and muscle strength values. This group also demonstrated higher parathyroid hormone and β-CTX levels and a lower P1NP/β-CTX ratio. Insufficient functional recovery was observed in 34.7% of patients with reduced vitamin D status and in 7.7% of patients with 25(OH)D levels of 30 ng/mL or higher. Conclusion. Vitamin D insufficiency and an imbalance in bone turnover markers are associated with less favorable functional recovery after total hip arthroplasty. Combined assessment of 25(OH)D, parathyroid hormone, P1NP, and β-CTX may serve as an additional tool for early risk strati­fication and personalization of medical rehabilitation programs.