Loaded open-kinetic-chain exercises stretch the anterior cruciate ligament more than closed-kinetic-chain exercises: In-vivo assessment of anterior cruciate ligament length change
- Standard of practice for ACL rehabilitation should include both open and close kinetic chain exercises throughout the entire course of treatment.
BACKGROUND & OBJECTIVE
There is no consensus regarding the safety of open kinetic chain (OKC) exercise during the early stages of rehabilitation following ACL reconstruction. Previously, it has been suggested that OKC knee extension at flexion angles ranging from 0 to 50 degrees create an increased shear force at the tibiofemoral joint compared to OKC knee extension at deeper flexion angles and closed kinetic chain (CKC) exercise (1).
Two recent systematic reviews and meta-analyses failed to identify any increased laxity associated with early introduction of OKC exercises (2, 3). However, many clinicians and surgeons remain fearful of OKC (4, 5). The aim of this study is to quantify the amount of strain placed on the ACL graft in both OKC and closed kinetic chain knee exercise.
It is still recommended that the maximally extended position for a weighted (10kg) OKC knee extension is limited to 30 degrees of knee flexion during the early phase of ACL rehabilitation.
The authors recruited 18 healthy subjects (11 men, 7 women), mean age 25, free of injury history or surgery, to participate in an in-vivo study using CT scan, fluoroscopy, and previously validated 3-D mapping models to quantify double bundle ACL