The association between radiographic severity and pre-operative function in patients undergoing primary knee replacement for osteoarthritis The Knee, 03/29/2012

Dowsey MM et al. – Osteophytes in the lateral compartment of the knee were associated with pre–operative function in patients with advanced knee osteoarthritis (OA).

• Single centre study examining pre–operative outcomes in a consecutive series of 525 patients who underwent primary knee replacement for OA between January 2006 and December 2007.
• Pre–operative data included: demographics, American Society of Anaesthesiologists (ASA) status and OA in the contralateral knee.
• The International Knee Society (IKS) rating and Short Form–12 (SF–12) were recorded for each patient.
• Pre–operative radiographs were read by a single observer for Kellgren and Lawrence (K&L) grading and Osteoarthritis Research Society International (OARSI) atlas features.
• Multiple linear regression was used to assess the strength of associations between radiographic OA severity and function, adjusting for clinically relevant variables.

• Lateral tibiofemoral osteophyte grade was an independent predictor of pre–operative function as determined by the functional sub–scale of the IKS in patients undergoing primary knee replacement (coefficient=2.58, p=0.033).
• No associations were evident between pre–operative function and modified K&L, joint space narrowing, Ahlbäck attrition and coronal plane deformity.
• Other statistically significant predictors of poorer pre–operative function included: advancing age, female gender, knee pain and poorer SF–12 mental component summary scores which including osteophyte grade accounted for 24.6% of the variation in functional scores, (r=0.496).