Effect of preoperative vitamin D deficiency on functional outcomes after high tibial osteotomy: a retrospective case control study

BACKGROUND: This study aimed to evaluate the effects of vitamin D deficiency on the functional outcomes following a high tibial osteotomy (HTO). METHODS: Clinical data of 209 patients (327 knees) who underwent HTO done by a single surgeon were retrospectively registered for the study. Ninety-four patients (94 knees) who underwent HTO were analyzed. Patients were assigned into two groups according to their preoperative serum vitamin D levels (D- Deficiency and S- Sufficient); < 20 ng/ml (group D, N = 48) and ≥ 20 ng/ml (group S, N = 46) respectively. A subjective form of International Knee Documentation Committee (IKDC) score, mechanical alignment, and cartilage status before and 1 year following HTO were studied between groups. RESULTS: The mean postoperative IKDC score was significantly higher in group S (p = 0.012). Moreover, the difference of IKDC score between pre- and post- HTO was also significantly higher in group S (p = 0.006). Preoperative vitamin D level and IKDC score did not show a significant correlation. Serum vitamin D level was found to be moderately correlated to postoperative IKDC score (r = 0.342 and, p = 0.001). A moderately positive correlation between serum vitamin D level and improvement of IKDC score following osteotomy was appreciated (r = 0.381 and, p < 0.001). CONCLUSION: Patients with vitamin D deficiency had less satisfactory functional outcomes within 1 year from HTO surgery. Our results suggest that preoperative serum vitamin D level is one of the factors affecting the outcome after HTO. We recommended analyzing serum vitamin D levels as part of the routine workup in patients undergoing HTO.