Volume 29, Issue 7 (10-2022)                   RJMS 2022, 29(7): 1-10 | Back to browse issues page

Research code: 17148
Ethics code: 93-02-30-24740-104043
Clinical trials code: IRCT 2014090719073N1

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Associate Professor of Sports Medicine, Minimally Invasive Surgery Research Center, Department of Sports and Exercise Medicine, School of Medicine, Hazrat-E Rasool General Hospital, Iran University of Medical Sciences, Tehran, Iran , mazaherinezhad@gmail.com
Abstract:   (1198 Views)
Background & Aims: Patellofemoral pain syndrome (PFPS) is one of the common causes of anterior knee pain, which is related to the intrinsic and extrinsic risk factors that affect the patellofemoral (PF) joint interface. The common causes of PFPS are: PF joint overloading, a disorder of patellar and femoral articular surface, knee muscular imbalance and weakness, an increase of Q angle, excessive subtalar pronation. This pathological chain can produce excessive compressive stress on the patellofemoral joint surface that causes nagging pain that significantly affects patients’ quality of life (QOL) and disability. The main factor of the therapeutic approach in conservative treatment of PFPS is exercise therapy including restoration of power balance quadriceps, improvement of the range of motion, as well as prevention of unequal compressive stresses on the PF joint. Generally, two exercise-based plans: Open kinetic chain (OKC) and closed kinetic chain exercises (CKC), have been employed for managing PFPS. It has been claimed that CKCs may provide more sensory feedback that could be effective in controlling joint stresses compared to OKCs. Quadriceps muscle actuates separately leading to an increase in PF compression stress; whereas muscular co-contraction occurs in CKCs that enhance joint stability and mitigate joint pain.
Despite the existence of some clinical evidence of the effectiveness of the two exercise programs in the treatment of PFPS, there is a scarcity of scientific reports showing which method is most effective. The present study aimed to compare the therapeutic effect of the OKC and CKC exercises on the pain and functional statement in patients with PFPS. 
Methods: This study was designed as a randomized clinical trial with ethical approval of the Research Ethics Committee of Iran University of Medical Sciences. It was conducted on 64 patients with PFPS who were referred to the Clinic of Sports Medicine in Rasoul-e-Akram hospital in Tehran, Iran. Inclusion criteria were: 1) age between 18-70 years, 2) pain in the anterior knee for at least two months with pain intensity equal to or higher than three based on the visual analog scale (VAS), 3) three or more positive clinical signs in the following tests: Clarke's sign, McConnell test, Nobel compression test, Waldron test, and patella in medial or lateral positions, 4) pain arose in at least two of the following situations: Resisted contraction of the quadriceps, squatting, prolonged sitting or kneeling, descending or ascending stairs, 5) normal mental state and 6) not participating in sports programs and physical therapy in the recent three months. On the other hand, exclusion criteria were: 1) history of previous surgery or injury in the knee, 2) history of acute traumatic injuries, 3) history of knee locking, 4) history of patellar dislocation or knee osteoarthritis, 5) history of knee intra-articular injection in the past six months, 6) Osgood-Schlatter disease, 7) unwillingness to participate in the study; 8) uncompleted evaluation programs; 9) any damage to the knee joint during the study and 10) using any therapeutic protocols. Therefore, outcome measurements were consisted of anthropometric parameters which were measured by the standard tools, pain intensity by VAS, 6-minute walking test (6MW test), timed up and go (TUG), sit-up test (numbers of sitting and getting up from a chair in 30 seconds), KUJALA anterior knee pain questionnaire and Functional Index Questionnaire (FIQ) for assessment of lower extremity function. The outcome measurements were carried out at three intervals: The baseline or pre-intervention, the 4th week, and the 8th week. Also, study intervention: A total of 117 patients with PFPS, 64 patients were included and randomly allocated to two groups, with 32 patients in each group. The participants began a 24-session program (three times per week) in each group after the pre-intervention assessment. All groups received the same warm-up exercises. OKC Protocol- the OKC group, received an exercise protocol that consisted of quadriceps setting, straight leg raise (SLR), and knee extension. CKC Protocol- the CKC group, received an exercise protocol that consisted of mini squat, Standing wall sit, and step up. Statistical analysis: The SPSS (version 16; SPSS Inc., Chicago, IL, USA) was reasonably applied to provide the analysis. The normality of data was analyzed using the Kolmogorov-Smirnov test. Independent t-test and repeated measurement were also fulfilled to compare the results over time within and between groups.
Results: Comparing the mean VAS pain score at baseline showed no difference between the OKC and CKC groups. And no difference was revealed in the mean KUJALA anterior knee pain score between the two groups before, one month, and two months after exercises. However, the results for the FIQ test were slightly different. Comparing the mean functional index between the subjects programmed for OKC and CKC exercises, it was presented that the CKC was slightly higher after two months of intervention. Again for the mean 6MW test, TUG test, and sit-up test, the difference was negligible between the two groups.
Conclusion: Findings in the present study showed that by planning both OKC and CKC training programs for eight weeks, a significant improvement in pain intensity and functional expression was achieved. Still, no priorities were determined between the two programs. As indicated by Witvirouw et al., an increase in the torque peak of the functional capacity of knee-related muscles and also pain reduction were found in both exercise groups. In a similar study, excellent results were revealed related to the pain and functionality.Contrary to our observation, Stiene et al., concluded that after an eight-week treatment, the CKC exercises were more effective than the OKC exercises. The above exposed statement suggests that both the OKC and the CKC exercises have been employed to treat the PFPS, but the OKC program seemed more effective in pain relief. Moreover, some studies could not demonstrate a discrepancy between the two exercise types. As indicated in a systematic review no significant differences in improvement of function or reduction of pain were apparent between the two types of exercise in any of the studies. There are significant differences between OKC and CKC protocols regarding action mechanisms and muscular effects. In OKC, a combination in which the terminal joint is free, while in CKC, one in which the terminal joint meets with some considerable external resistance that prohibits or restrains free movement. Also, in OKC, the distal end is opened, whereas, in CKC, the motion of one segment at one joint will produce motion at all other joints in the system in a predictable manner. In CKC exercise, the main basis is an exercise with greater proprioceptive input leading to an increase in proprioceptive ability, increasing joint compressive forces and knee stability, and thus increasing muscular performance. Totally, CKC exercise seemed to be safe because of decreasing shear force and increased muscle co-contraction. Unlikely, some advantages have also been pointed out for OKC versus CKC exercise, including improving strength and increasing ROM at specific joints, correcting strength deficits of specific muscles or joints, and beginning rehabilitation when athletes are not able to perform CKC exercises. It has been demonstrated that OKC and CKC exercises are equally effective in pain reduction and functional improvement. They are strongly recommended as rehabilitation protocols in patients with PFPS. However, why one protocol is superior to another remains controversial and needs further assessment.

 
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Type of Study: Research | Subject: Sports Medicine

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