The effect of total knee prosthesis coronal ali̇gnment angles on functional results and patient satisfaction

Purpose: Total knee prothesis (TKP) is one of the most successful surgical procedures of modern medicine. On the other hand, %20 percent of the patients are dissatisfied with the result. The relationship between the patient satisfaction and TKP alignment angle variations is being examined for a long time. In our daily practice mechanical alignment principles are commonly being used for TKP. Keeping "Hip knee ankle" angle (HKA) inside neutral alignment angles (180°±3°) is the golden standard for mechanical alignment. The main purpose of this study is to evaluate the effect of alignment variations on clinical and functional scores in short and midterm (1 year and above) in the patients having been applied primer posterior stabilized total knee prothesis. Material and methods: 327 knees of 242 patients operated on between the periods of 1.11.2015 and 31.3.2021 at Sakarya University Orthopaedic and Traumatology Department were examined retrospectively. Average follow-up time was 17 months (range12-64) months. To assess patient reported outcome measures("PROMs") Oxford Knee Score (OKS), American Knee Society Score-functional score (KSS-FS), Osteoarthritis Index of Western Ontario and McMaster Universities (WOMAC) forms that filled before the operation and one year after the operation were used. The orthographies and AP-lateral knee XRAYs taken before and after operation. The alignment of the lower extremity before and after the operation and the coronal and sagittal plan alignment of TKP components were measured by independent researchers. The data obtained was statistically compared. Findings: The patients were followed up for an average of 17 months. Preoperative HKA values ​​of almost all patients were measured in varus. It was measured that 231 of 327 knees were not in neutral mechanical alignment and were varus aligned after surgery. It was determined that TKP surgery statistically significantly increased functional scores in all patients. However, when the post-op KSS, post-op OCS and post-op WOMAC values ​​were examined, no statistically significant difference was found between the patients with varus and neutral postoperative HKA alignment values ​​(p values ​​0.004, 0.019, 0.001, respectively) (p>0.05). Results: In our study, it was determined that TDP coronal alignment angle differences did not have a statistically significant effect on patient satisfaction and functional results in the short-medium term. We think that low patient satisfaction after TKP surgery is not caused by angular differences in lower extremity alignment and extensive soft tissue releases to achieve neutral alignment do not contribute to patient functional scores, but are interventions that require experience and carry some risks. Key words knee, alignment, gonartrosis, osteoarthritis, PROM, TKA,