The effect of alignment on knee osteoarthritis initiation and progression differs based on anterior cruciate ligament status: data from the Osteoarthritis Initiative.

The impact of knee alignment on knee OA initiation and progression varies based on ACL status. Initial lateral compartment damage or changes in joint kinematics after ACL rupture might account for these findings.Key Points• The relationship between knee alignment and lateral compartment cartilage loss depended on the status of the anterior cruciate ligament in participants with knee osteoarthritis or at risk for knee osteoarthritis.• Valgus alignment was related to lateral compartment cartilage loss in participants with a deficient anterior cruciate ligament.• Varus alignment was related to medial compartment cartilage loss regardless of the status of the anterior cruciate ligament.