Comparison of the functional results of patients who underwent single-radius total knee prosthesis and multi-radius total knee prosthesis

Objective: The advantage of single-radius (SR) design femoral components is that they create a longer extensor moment arm with a single instantaneous center of rotation located more posteriorly than multi-radius (MR) prostheses. Thus, it has been suggested that it will cause less anterior knee pain and provide more compatible patellofemoral movement. However, there is debate as to whether the SR TDA, which is a newer design, has superior functional results than MR TDA. The aim of this study; to compare the clinical and functional results of SR and MR femoral components in TKA. Patients and Methods: A total of 74 patients who underwent TKA surgery by a single surgeon between 2018 and 2021 with the diagnosis of advanced osteoarthritis were included in the study. The patients were then divided into two groups according to their femoral component design: group SR (38 patients; 2 patients M, 36 patients F; mean age = 68.63 ± 7.68) and group MR (36 patients; 8 patients M, 28 patients F; mean age = 68.06 ± 7.73). The two patient groups were similar in age and body mass index (p > 0.05). Mean follow-up times were 30.39±7.74 (range, 15–45) and 37.92±10.54 (range, 12-48) months, respectively. The follow-up times of those with MR were found to be statistically significantly higher than those with SR (p=0.001; p<0.01). Knee range of motion, VAS, KSS, and KSS function scores were evaluated at the preoperative and final controls of the patients. In addition, anterior knee pain, Kujala score, chair rise test, WOMAC, HSS, and UES-12 were evaluated at the final follow-up. Results: The incidence of anterior knee pain in patients with SR was found to be statistically lower than those with MR (p=0.021; p<0.05). The Kujala score was found to be statistically significantly lower in patients with prosthetic type MR compared to patients with SR (p=0.04; p<0.05). SR patients had significantly better UES-12 (84.33 ± 18.85 and 71.39 ± 24.88; p=0.014; p <0.05) and WOMAC score (93.94 ± 5.84 and 89.89 ± 6.92; p=0.003; p<0.05). There was no difference between the two groups in terms of postoperative ROM, chair rise test, VAS, KSS, KSS function, and HSS (p>0.05). Conclusion: The results of our research showed that good clinical and functional results are obtained with TKA regardless of the femoral component design. SR prostheses show better results than MR prostheses in terms of frequency and severity of anterior knee pain. While there is no difference between femoral designs in terms of knee-specific functional results such as KSS and HSS, the WOMAC score, which measures disease-related functions, provides better clinical results in SR designs.