The Effectiveness of Open Versus Closed Kinetic Chain Exercises In Accelerated Rehabilitation After Anterior Cruciate Ligament Reconstructive Surgery: A Systemic Review Malak Azab PT Purpose The purpose of this work was to investigate the effectiveness of OKC compared to CKC in accelerated rehabilitation after anterior cruciate ligament reconstructive surgery. Methods A computerized search of the literature was performed using the following databases: MEDLINE, CINHAL, COCHRANE and PEDro database. The key words for the search were: ACL reconstruction, ACL rehabilitation, open kinetic chain, closed kinetic chain, and exercises. Studies meeting the following criteria were selected for review: (1) Studies were related to open versus closed kinetic chain exercises and their effect in accelerated rehabilitation after anterior cruciate ligament reconstructive surgery. (2) Meta- analysis and randomized controlled trials; and, (3) Published in a peer reviewed source Table 1 summarizes the literature that indicates the effectiveness of OKC versus CKC exercises in accelerated rehabilitation after ACL reconstructive surgery.CitationPurposeSubjectsInterventionsResults Perry et al., This study compared the effects of closed and open knee exercises on knee laxity and functions in patients with ACLD knees. 64 participants with knee anterior Cruciate ligament deficiency. Their age was between (49 males and 15 females). Were randomized to two groups CKC group (n=32); OKC group (n=32). The CKC group received CKC strengthening exercises for the hip and knee extension. The OKC group received OKC knee strengthening exercises for the hip and knee extensor. Strengthening exercises were performed: 3 sets of 20 each session until the wk 4 then 3 sets of 6 at wk 6. The results of this study showed that OKC and CKC knee extensors exercises have no significant differences in their effect on knee laxity and functions with patients with ACLD knees. Morrissey et al., This study compared the effect of CKC and OKC on the level of knee pain in the early stage after ACL reconstruction. 43 subjects with ACL reconstruction surgery, Their age between (9 females and 34 males) were randomized to two treatments groups. Group C (CKC training) (n=21); and Group O (OKC training) (n= 22) Group C received CKC exercises for hip and knee extensors muscles. Group O received resistance for hip and muscle extensors group. all participants received 3 sessions per wk for 4 wks. Resistance exercises were 3 sets of 20 RM in each session with no additional resistance exercises. The results showed that there were no differences between the two groups in muscle performance; also there was no significant change in pain reduction between CKC and OKC groups. The results showed that there were no differences between the two groups in muscle performance; also there was no significant change in pain reduction between CKC and OKC groups. Morrissey et al., This study compared the effect of OKC versus CKC on knee laxity in the early stage following ACLR. 36 participants with ACL reconstructive surgery, with a mean age of 30 were assigned randomly to two groups CKC (18 with 6 F and 12 M) OKC (18 with 1 F and 17 M). CKC group received CKC resistive exercises for the knee and hip extensor. The OKC group received resistive exercises for the hip and knee extensor. Both groups received physical therapy 3T X WK X 4 wks and with 3 sets of 20 repetitions in each session. The results showed no statistically significant differences between OKC and CKC training exercises of knee and hip extensor in the knee laxity or anterior tibial displacements (ATD) in the early period following ACLR. Mikkelsen et al., This study compared CKC program versus a combined program of CKC and OKC for quadriceps hamstring strength, knee laxity, and return to sport after ACLR. This study compared CKC program versus a combined program of CKC and OKC for quadriceps hamstring strength, knee laxity, and return to sport after ACLR. 44 participants with ACL reconstruction with ages between (18- 40) years were assigned randomly to two groups. CKC group (17 M and 5 F) and CKC combined with OKC group (17 M and 5 F). 1 st group received only CKC quadriceps exercises. The 2 nd group received the same quadriceps CKC exercise as in the 1 st group, but from the 6 th wk after the surgery OKC quadriceps exercises were added. The rehabilitation period was for 6 months. There were no significant differences between both groups in knee laxity at 6 month. OKC combined with CKC showed a significant improvement in the concentric and eccentric strength of quadriceps at 6 month, and no difference in strength of hamstring. Combined group returned earlier to sport than CKC group. References 1- Perry MC, Morrissey D, Knight PR, McAuliffe TB, King JB: Knee extensors kinetic chain training in anterior cruciate ligament deficiency. Knee Surg Sports Traumatol Arthro Nov;13(8): Epub 2005 May 5. 2-Morrissey MC, Drechsler WI, Morrissey D, Knight PR, Armstrong PW, McAuliffe TB: Effects of distally fixated versus no distally fixated leg extensor resistance training on knee pain in the early period after anterior cruciate ligament reconstruction. Phys Ther Jan; 82(1): Morrissey MC, Hudson ZL, Drechsler WI, Coutts FJ, Knight PR, King JB: Effects of open versus closed kinetic chain training on knee laxity in the early period after anterior cruciate ligament reconstruction. Knee Surg Sports Traumatol Arthro. 2000; 8(6): Mikkelsen C, Werner S, Eriksson E:Closed kinetic chain alone compared to combined open and closed kinetic chain exercises for quadriceps strengthening after anterior cruciate ligament reconstruction with respect to return to sports: a prospective matched follow-up study. Knee Surg Sports Traumatol Arthro. 2000;8(6): Graham VL, Gehlsen GM, Edwards JA: Electromyographic Evaluation of Closed and Open Kinetic Chain Knee Rehabilitation Exercises. J Athl Train Spring; 28(1): Introduction Anterior cruciate ligament (ACL) injuries are common in athletes. The mechanism of injury usually occurs with deceleration of the planted limb’s tibia in relation to the femur combined with turning around, pivoting, twisting, or changing of direction suddenly (valgus stress at knee joint combined with sudden rotation). The ACL plays a very important part in establishing the functional stability of the knee and is considered a primary restraint to the anterior translation of the tibia on the femur. During the last 10 years there was a move toward favoring closed kinetic chain exercises (CKC) over the open kinetic chain (OKC) exercises in the rehabilitation of the ACL for the following reasons: 1- Decreases the anterior shear forces between tibia and femur; 2- Decrease the compression forces of the tibiofemoral joint; 3- Increase the hamstrings co contraction; 4- CKC exercises are involved in most of our daily living activities than OKC exercises; and, 5- Decrease the complication of patellofemoral joint as chondromalacia, patella maltracking, patella tendenosis, and pre patellar bursitis. One of the very important decisions the clinician has to make is to choose which program is more effective in accelerating the rehabilitation process after an ACL injury. Because of the above reasons we are trying to investigate the effectiveness of CKC versus OKC exercises after ACL reconstruction. CKC exercises replicate most of our daily living activities. A strong quadriceps muscle plays an important role in preventing ACL injury and in accelerating the rehabilitation following ACL reconstruction by preventing the anterior translation of the tibia. Due to the confusion regarding which program is more effective following the anterior cruciate ligament reconstruction (ACLR), it is important to understand the role of quadriceps and hamstring muscles during daily living activities. During the OKC activities (kicking, swimming, wrestling), the hamstrings are considered an ACL protector or agonists, and the quadriceps as antagonists. While as during CKC activities (running, standing, walking, jumping, skiing), the quadriceps plays the role of ACL supporter or main protagonists of ACL. Results Twelve studies were selected according to the mentioned criteria. Five studies investigated the effect of open kinetic chain and closed kinetic chain exercises on knee function, laxity and level of pain in the early stage after ACL reconstruction. Two studies compared different types of CKC exercises in their effect during ACL rehabilitation. Four studies reflect the effect of CKC exercises in accelerated rehabilitation after ACLR and the functional outcome. One study investigated the biomechanics of the knee during OKC and CKC exercises. Discussion This review summarizes the results of twelve studies that investigate the effect of OKC and CKC exercises on knee function, laxity and pain level, different types of CKC exercises, effect of CKC exercises in accelerated rehabilitation after ACLR and the functional outcomes, and the biomechanics of the knee during OKC and CKC exercises. ● Four studies reflect the effect of CKC exercises in accelerated rehabilitation after ACLR and the functional outcome. It was found that CKC exercises have a very important role in strengthening the quadriceps muscle, and they may be protecting the ACL grafts. ● Two studies compared different types of CKC exercises in their effect during ACL rehabilitation. It was found that CKC exercises decrease the anterior shear force so it can be safely used after ACLR. ● One study investigated the biomechanics of the knee during OKC and CKC exercises. And found that OKC exercises plays an important role in strengthening rectus femoris while as CKCE plays an important role in strengthening vasti muscles. ● Five studies investigated the effect of OKC and CKC exercises on knee function, laxity and pain level after ACLR and found that no differences between both programs. Conclusion The review supports that there are no differences between OKC and CKC exercises in their effect on accelerated rehabilitation after ACLR. It can be concluded that combining OKC and CKC exercises could be more effective in accelerated rehabilitation. Recommendation Further randomized clinical trials are needed to be done to determine the best time to starts these exercises and to investigate how and when to combine OKC and CKC exercises to accelerate rehabilitation of ACLR and to provide strong evidence about selective OKC and CKC exercises that could be used in acceleration rehabilitation after ACLR.