The Relationship Between Early-Stage Knee Osteoarthritis and Lower-Extremity Alignment, Joint Laxity, and Subjective Scores of Pain, Stiffness, and Function

Context: Knee osteoarthritis (OA) is a debilitating disease that affects an estimated 27 million Americans. Changes in lower extremity alignment and joint laxity have been found to redistribute the medial and/or lateral loads at the joint. However, the effect that changes in anteroposterior knee-joint laxity have on lower-extremity alignment and function in individuals with knee OA remains unclear. Objective: To examine anteroposterior knee-joint laxity, lower-extremity alignment, and subjective pain, stiffness, and function scores in individuals with early-stage knee OA and matched controls and to determine if a relationship exists among these measures. Design: Case control. Setting: Sports-medicine research laboratory. Participants: 18 participants with knee OA and 18 healthy matched controls. Intervention: Participants completed the Western Ontario McMaster (WOMAC) osteoarthritis questionnaire and were tested for total anteroposterior knee joint laxity (A-P) and knee joint alignment (ALIGN). Main Outcome Measures: WOMAC scores, A-P (mm), and ALIGN (degrees). Results: A significant multivariate main effect for group (Wilks' Lambda = 0.30, F-7,F-26 = 8.58, P < .0001) was found. Knee-OA participants differed in WOMAC scores (P < .0001) but did not differ from healthy controls on ALIGN (P = .49) or total A-P (P = .66). No significant relationships were identified among main outcome measures. Conclusion: These data demonstrate that participants with early-stage knee OA had worse pain, stiffness, and functional outcome scores than the matched controls; however, ALIGN and A-P were no different. There was no association identified among participants' subjective scores, ALIGN, or A-P measures in this study.