Severity Of Radiographic Osteoarthritis: Association with Improved Patient Reported Outcomes Following Knee Arthroplasty

Abstract

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.