Younger patients have less severe radiographic disease and lower reported outcome scores than older patients undergoing total knee arthroplasty

Abstract

Background: Total knee arthroplasty (TKA) has been successful for many younger patients, but some experience residual symptoms or dissatisfaction. We performed this study to assess the relationship between radiographic disease severity and patient demographic features on patient reported TKA outcome scores.

Methods: We compared 100 TKAs performed for 82 patients ≤55years old with 100 gender-matched TKAs performed for 85 patients between 65 and 75years old. These study cases represented 25% and 21%, respectively, of TKAs performed between January 2006 and June 2011. Radiographic disease severity was determined from preoperative weight bearing AP and lateral radiographs. Patient reported outcome instruments (SF-12, Knee Society function, and WOMAC) were assessed for all patients within six months before surgery and postoperatively at a mean of 20months after TKA.

Results: Although younger patients had less mean articular cartilage loss (p<0.01), osteoarthritis severity (p<0.01), and Kellgren-Lawrence grade (p=0.05), they reported lower preoperative scores (p<0.01) exceeding the MCID for SF-12 mental health (8.3 points), WOMAC pain (12.1 points), and WOMAC physical function (6.9 points). While substantial improvement was noted, WOMAC pain scores remained lower than those reported by older TKA patients (11.5 points, p<0.05).

Conclusion: Younger patients with less severe radiographic arthritis experience significant improvement with TKA, but outcome scores do not match those attained by older patients with more severe radiographic disease.

Keywords: Osteoarthritis; Outcome; TKA; Young patient.