Evaluation of the Effect of Two Exercise Regimes in Producing Forces on Anterior Cruciate Ligaments: A Systematic Review

A Peer Reviewed Publication of the College of Allied Health & Nursing at Nova Southeastern University Dedicated to allied health professional practice and education http://ijahsp.nova.edu Vol.5 No. 2 ISSN 1540-580X Evaluation of the Effect of Two Exercise Regimes in Producing Forces on Anterior Cruciate Ligaments: A Systematic Review Barbara Pumberger Carla van Usen University of South Australia Citation: Pumberger, B., van Usen, C. Evaluation of the Effect of Two Exercise Regimes in Producing Forces on Anterior Cruciate Ligaments: A Systematic Review. The Internet Journal of Allied Health Sciences and Practice. April 2007, Volume 5 Number 2. Abstract Background: Anterior cruciate ligament (ACL) injuries are common. A goal of rehabilitation is to restore functional capacity. Currently, there are contrary opinions regarding the effectiveness of using either closed or open kinetic chain exercises (CKC, OKC) only, or a combination of both, following ACL injury, to obtain the most effective outcome. The debate also reflects the approach which places the least force on the ACL itself. Objective: To identify the evidence of effectiveness of closed versus open kinetic chain exercises, or a combination of both, in anterior cruciate ligament rehabilitation. Methods: A systematic review was undertaken of experimental studies published since 1990. Included studies were on humans with ACL injury. The ACL ligament could be healthy, ruptured, deficient or reconstructed. Studies on animals and cadavers were excluded. The methodological quality of included studies was appraised with the PEDro tool. Studies were graded according to hierarchy level, methodological quality, statistical significance, effect size, and clinical relevance. Recommendations were made on the strength of the body of evidence. The outcome measure of interest was force on the ACL during exercise. Results: 23 eligible studies were included. The majority of studies reflected lower level experimental designs with moderate methodological quality. Three studies showed a significant difference in ACL force comparing CKC and OKC exercises, 11 demonstrated trends towards significant differences in outcome and nine showed no significant differences. Conclusion: There is moderate evidence to recommend CKC exercises or a combination of CKC and OKC exercises, rather than OKC exercises alone, for ACL rehabilitation when considering forces on the ACL. ___________________________________________________________________________________________________ Background a clearer picture of which of these two treatment This systematic review considered the available research approaches alone, or in combination, optimises recovery evidence for best practice in rehabilitation of Anterior by minimising ACL strain during exercise. cruciate ligament ACL injuries, considering strain placed on the ACL during exercise. ACL injuries are common Treatment approaches using OKC and CKC exercises for disorders resulting from workplace or recreational ACL injuries have been subject of debate over the past injuries, which are frequently treated by physiotherapists decade. It was first reported in 1993 that greater anterior using a variety of approaches.1 A common goal after ACL tibial displacement (ATD) occurred during open injury, or reconstruction surgery, is to protect the compared with closed kinetic chain resistance exercises ligament, and strengthen surrounding structures whilst of the knee extensors.3 This facilitated a shift towards reducing forces on the patellofemoral joint.2 Open kinetic CKC training in clinical practice in the following years. chain (OKC) and closed kinetic chain (CKC) exercises Reasons to support a change in rehabilitation are two exercise approaches which are often used in approaches towards CKC training were also provided by rehabilitation programs. There is currently no agreement Fleming, Oksendahl & Beynnon,1 (p.134) such as: in the research literature on whether OKC or CKC exercises produce a better outcome, specifically 1. ‘reducing the anterior-directed intersegmental regarding which exercise places the least stress/strain on forces that act on the tibia relative to the femur the ACL during rehabilitation. Minimising strain protects 2. increasing tibiofemoral compressive forces this important knee structure during rehabilitation, as well 3. increasing co-contraction of the hamstrings as the integrity of entire knee joint. This systematic 4. mimicking functional activities more closely review of the research literature was undertaken to obtain than OKC exercises Evaluation of the Effect of Two Exercise Regimes in Producing Forces on Anterior Cruciate Ligaments: A Systematic Review 2 ____________________________________________________________________________________________________________________________ 5. reducing the incidence of patellofemoral complications’. However, it has since been queried whether the two exercise regimes actually differ in the strain placed on the ACL.4 There are also suggestions that a combination of CKC and OKC exercises could be more effective than one exercise type alone.1,2 There is currently no convincing argument regarding which exercise approach produce the least stress/strain on the ACL.5-7 Thus, a better understanding of the effects of these exercises is required from reviewing the literature. The literature provides a variety of definitions for CKC and OKC exercises, and there is ongoing discussion regarding whether these terms describe these therapeutic exercises appropriately. For the purpose of this systematic review the most common definitions are used. OKC exercises are typically non-weight bearing, and motion occurs independently in one joint with the distal segment free to move, such as when seated knee extension is performed with resistance applied distally. Conversely CKC exercises are typically weight bearing. Movement at one joint, produces movement at several other joints, the terminal segment is normally fixed, and the resistance can be applied proximally and distally. A good example for a CKC exercise would be a squat.8-10 The aim of this systematic review was to review and evaluate the current evidence on the difference in effect of CKC versus OKC exercises, in order to determine if one approach produces less strain on the ACL and therefore should be favoured during rehabilitation. Methods Research question: What is the difference in effect of closed versus open kinetic chain exercises in producing strain on anterior cruciate ligament? Search terminology: Appendix 1 provides details on the search definitions and terms. All possible combinations of search terms were used in the databases. Only evidence available in full text articles in English language was included. Selection criteria: Only experimental studies were included. Eligible studies could comprise studies of OKC with, or without control, CKC with, or without control or CKC compared to OKC exercises (...truncated)