Effects of Distally Fixated Versus Nondistally Fixated Leg Extensor Resistance Training on Knee Pain in the Early Period After Anterior Cruciate Ligament Reconstruction

Abstract

Abstract Background and Purpose. Nondistally fixated (ie, what is often referred to as “open kinetic chain” [OKC]) knee extensor resistance training appears to have lost favor for some forms of rehabilitation due partly to concerns that this exercise will irritate the extensor mechanism. In this randomized, single-blind clinical trial, nondistally fixated versus distally fixated (ie, often called “closed kinetic chain” [CKC]) leg extensor training were compared for their effects on knee pain. Subjects. Forty-three patients recovering from anterior cruciate ligament (ACL) reconstruction surgery (34 male, 9 female; mean age=29 years, SD=7.9, range=16–54). Methods. Knee pain was measured at 2 and 6 weeks after ACL reconstruction surgery using visual analog scales in a self-assessment questionnaire and during maximal isometric contractions of the knee extensors. Between test sessions, subjects trained 3 times per week using either OKC or CKC resistance of their knee and hip extensors as part of their physical therapy. Results. No differences in knee pain were found between the treatment groups. Discussion and Conclusion. Open kinetic chain and CKC leg extensor training in the early period after ACL reconstruction surgery do not differ in their immediate effects on anterior knee pain. Based on these findings, further studies are needed using different exercise dosages and patient groups.