The impact of metabolic syndrome on patient-reported outcome measures after primary total knee arthroplasty in osteoarthritis patients

Abstract

Abstract Background As the proportion of patients with metabolic syndrome (MetS) among those undergoing total knee arthroplasty (TKA) for osteoarthritis increases annually, the impact of MetS on patient-reported outcome measures (PROMs) after TKA has been the subject of conflicting research findings. Our goal is to determine the influence of MetS on PROMs during the first year after TKA and its associated trajectory of change. Methods We reviewed data from patients receiving their primary TKA,. Using the full-length X-ray of the patient's lower limb. We calculated the Metabolic Score for Insulin Resistance (MetS-IR) to reflect the severity of metabolic syndrome and used Maximally Selected Test Statistics to divide patients into two groups based on MetS-IR. We analyzed pre- and post-TKA OKS as PROMs and further analyzed OKS pain and function subscores. Results A total of 124 patients were included in the study. The selected cutoff value for MetS-IR was 43. Patients with MetS-IR < 43 were classified as Group 1 (n=79), while those with MetS-IR ≥ 43 were classified as Group 2 (n=45). Patients in Group 2 were younger (63.26±6.23, P<0.05), had poorer preoperative OKS scores (22 (17), P<0.05), more severe intra-articular deformities (JLCA: 6.01±2.99, MAD: 33.11±19.29, P<0.05), and higher levels of inflammation (CRP: 3.67 (2.15), P<0.05). Furthermore, CRP levels remained elevated at 1 month (7.19 (4.42)) and 3 months (5.24 (2.66)) postoperatively. Although postoperative OKS scores were lower in Group 2 than in Group 1, the improvement in OKS was higher in Group 2. Multiple regression analysis showed that MetS-IR was an independent predictor of OKS (β= -0.45, -0.19, -0.17, -0.24, p<0.05) and could predict preoperative, 3-month, 6-month, and 12-month OKS. Conclusion MetS-IR has a better predictive ability for early postoperative outcomes after TKA compared to the clinical classification of metabolic syndrome. Patients with high MetS-IR show greater improvement compared to those with low MetS-IR, however, their OKS levels remain relatively lower. MetS-IR is an independent predictive factor for OKS in OA patients before and after TKA, and a higher preoperative MetS-IR suggests lower postoperative PROMs. These findings may provide valuable insights for improved understanding and management of these patients.