Severity of radiographic osteoarthritis: Association with improved patient reported outcomes following knee arthroplasty

Introduction:The Kellgren and Lawrence (KL) classification for knee osteoarthritis estimates disease severity. Its utility in predicting patient-reported outcomes (PROs) after primary total knee arthroplasty (pTKA) has been suggested. We hypothesized that patients who had higher preoperative KL grades would demonstrate greater improvements in PROs after pTKA.Methods:This was a retrospective review of patients who underwent pTKA between 2016 and 2021. Two observers graded preoperative radiographs (KL1/2, KL3, and KL4). Knee Injury and Osteoarthritis Outcome Score (KOOS) for activities of daily living (KOOS-ADL) and pain (KOOS-Pain) were collected at preoperative and 12-month postoperative visits. Changes in KOOS-ADL (ΔADL) and changes in KOOS-Pain (ΔPain) scores were compared from the preoperative to 12-month postoperative mark across different groups, with the minimal clinically important difference (MCID) for both ΔADL (MCID-ADL) and ΔPain (MCID-Pain) also being calculated. A P-value of < 0.05 was considered statistically significant.Results:A total of 1651 patients were included in the study. The KL3 and KL4 groups exhibited significantly higher ΔADL scores and ΔPain scores compared with the KL1/2 group (P < 0.01). Patients who had KL3 and KL4 were 1.42 (P = 0.03) and 1.88 (P < 0.01) times, respectively, more likely to achieve MCID-ADL compared with those who had KL1/2. Furthermore, patients who had a KL4 were 1.92 times (P < 0.01) more likely to reach MCID-Pain compared with those who had KL1/2.Conclusions:This study determined that patients who had higher preoperative KL grades experienced markedly greater improvements in KOOS-ADL and KOOS-Pain scores than those who had lower KL grades. These findings offer surgeons an objective tool when counseling patients on expected outcomes after pTKA.