Summery of the best practice evidence for open kinetic chain exercise after ACLR
This briefing document synthesizes information about using Open Kinetic Chain (OKC) exercises during rehabilitation after ACL surgery. It defines OKC exercises, contrasting them with Closed Kinetic Chain exercises, and discusses the timing of when to start OKC exercises post-surgery, noting a shift from purely time-based decisions to criteria-based progression.
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1. Defining OKC and CKC Exercises:
- Closed Kinetic Chain (CKC): Defined as exercises where “the distal aspect of the extremity is attached to a stationary object.”
- Open Kinetic Chain (OKC): In contrast, “OKC exercise modality results in resistive loads being applied to the tibia and transmitted directly to the knee, where only muscles spanning the knee are engaged by exercise… OKC can be defined as a form of single-joint motion exercise in which only distal segment motion occurs with no proximal segment motion.”
2. Timing of OKC Introduction Post-ACLR:
Current recommendations suggest starting OKC exercises around 4 weeks post-surgery. The reviewed studies categorized the start of OKC interventions as:
- Before 4 weeks
- Between 4 and 6 weeks
- After 6 weeks
The median start time across the studies reviewed in the first source was 4 weeks post-surgery, with a range from immediately to 12 weeks.
3. Impact of OKC Exercises on Muscle Strength and Graft Laxity:
- Quadriceps Strength: Significantly higher Limb Symmetry Index (LSI) and Peak Torque to Body Weight ratio (PT/BW) in the OKC + CKC group compared to the CKC-only group (p < .001 for both time points).
- Hamstring Strength: Similarly, the OKC + CKC group showed significantly better hamstring strength LSI and PT/BW at both 3 and 6 months.
- Graft Laxity: Importantly, “No significant difference in laxity was observed between the intervention and control groups at 3 or 6 months.”
