Preoperative lower radiographic osteoarthritis severity in primary total knee arthroplasty increases revision risk by tenfold compared to severe osteoarthritis

BACKGROUND: Dissatisfaction following primary total knee arthroplasty (pTKA) is higher in patients with preoperative low-grade osteoarthritis (OA), but its impact on revision risk remains unclear. QUESTIONS/PURPOSES: This study aimed to identify predictors for revision surgery within 10 years following pTKA, focusing on radiographic severity of OA using the Kellgren-Lawrence (KL) grading system, along with other demographic and radiographic factors. PATIENTS AND METHODS: This retrospective case-control study was conducted at two European tertiary referral centers. The case group included 142 patients who underwent aseptic revision total knee arthroplasty (rTKA) between 2007 and 2023, within 10 years following pTKA. A 2:1 control group of 284 patients who had pTKA between 2011 and 2014, with no revision surgery within 10 years, was selected. Collected data included age, sex, body mass index (BMI), side of surgery, and American Society of Anesthesiologists (ASA) classification. Radiographic data were collected, requiring a preoperative radiograph to assess the KL grade. Univariate analyses identified potential predictors for rTKA, and multivariable logistic regression assessed their relationship with revision risk. RESULTS: Patients requiring rTKA were significantly younger at the time of pTKA. For each additional year of age, the revision risk decreased by 6% (OR 0.94, 95% CI 0.92 to 0.97; p < 0.001). Men were at a fourfold higher risk for revision compared to women (OR 4.01, 95% CI 2.41 to 6.69; p < 0.001). Patients with KL grade 2 OA were ten times more likely to need revision compared to those with KL grade 4 (OR 10.12, 95% CI 5.19 to 19.74; p < 0.001). CONCLUSIONS: Revision surgery risk following pTKA was associated with younger age, male sex, and less severe OA. These results emphasize the importance of appropriate patient selection for pTKA, enabling better identification of high-risk patients and improving preoperative counselling to optimize long-term outcomes. LEVEL OF EVIDENCE: III.