Changes in Glycemic Parameters Following Total Knee Arthroplasty in Patients With Type 2 Diabetes Mellitus: A Retrospective Observational Study in a South Indian Population

Background Knee osteoarthritis (OA) is a major cause of disability among older adults and is frequently associated with type 2 diabetes mellitus (DM). Pain and functional limitation in advanced OA may contribute to reduced mobility and poorer glycemic control. Although total knee arthroplasty (TKA) reliably improves pain and function, changes in glycemic parameters following TKA have not been well characterized. This study evaluated changes in glycemic parameters following TKA in patients with type 2 DM. Methods A retrospective observational study was conducted in patients who underwent primary TKA for tricompartmental OA between January and November 2016. Patients aged >50 years with established type 2 DM receiving an unchanged antidiabetic regimen throughout follow-up were included. Fasting blood glucose (FBS), postprandial blood glucose (PPBS), glycated hemoglobin (HbA1c), and Lower Extremity Activity Scale (LEAS) scores were assessed preoperatively and at 12 months postoperatively. Paired t-tests were used to compare the preoperative and postoperative outcomes, and Pearson correlation analysis was performed to examine the associations between postoperative LEAS scores and glycemic parameters. Results A total of 110 patients met the initial eligibility criteria. Ten patients were excluded from the final analysis because of discontinuation or modification of antidiabetic therapy during follow-up, leaving 100 patients for analysis (46 women and 54 men; mean age, 62 years (range, 55-93)). LEAS scores improved significantly from 7.4±0.9 to 12.8±1.5 (p<0.001). Significant reductions were observed in FBS (139.6±36.1 to 105.5±16.9 mg/dL), PPBS (203.5±40.9 to 149.6±28.8 mg/dL), and HbA1c (7.3±0.9 to 6.6±0.7) (all p<0.001). Postoperative LEAS scores demonstrated significant negative correlations with FBS and PPBS but were not significantly correlated with HbA1c. Conclusions In this selected cohort of patients with type 2 DM who remained on an unchanged antidiabetic regimen, glycemic parameters were observed to be reduced and lower extremity functional status improved at 12 months following TKA compared with baseline. These findings represent an observational association rather than evidence of a causal effect and should be interpreted in the context of the retrospective, uncontrolled study design. Prospective controlled studies are needed to determine the independent relationship between TKA and long-term glycemic outcomes.