Full length articleComparing the effects of mechanical perturbation training with a compliant surface and manual perturbation training on joints kinematics after ACL-rupture
Introduction
The anterior cruciate ligament (ACL) is the most injured ligament in the knee joint in athletic individuals, with 250,000 ACL-ruptures occurring annually in the United States [[1], [2], [3]]. Majority of patients with ACL-rupture exhibit dynamic knee instability during a variety of daily living and functional activities [[4], [5], [6], [7]]. Other complications commonly present after ACL-rupture include quadriceps weakness, range of motion deficits, impaired knee function, limb-to-limb movement asymmetry, and altered knee biomechanics [[4], [5], [6], [7]]. These complications, if not resolved, can affect the patients’ ability to participate in dynamic functional activities and may predispose the knee joint to further injuries or the development of joint osteoarthritis [8,9].
The incidence of dynamic knee instability may indicate a failure of the neuromuscular system to provide sufficient stability after ACL-rupture. Patients adapt abnormal gait patterns and decrease the intensity and level of activity participation to counteract experiencing dynamic knee instability [[10], [11], [12], [13]]. The combination of repeated episodes of knee instability and altered knee biomechanics are problematic to joint heath as they may cause further injuries to the intra-articular structures of the knee joint [[14], [15], [16]]. Therefore, rehabilitation treatment programs are needed to target and improve dynamic knee control and limit potentially negative sequelae.
Administering progressive quadriceps strengthening augmented with manual perturbation training have become standard treatments for patients with ACL-rupture who opt for non-operative management [[17], [18], [19]]. Manual perturbation training, type of neuromuscular training exercise, has been shown to be an effective intervention for improving dynamic knee stability and restoring knee motion during gait [[20], [21], [22], [23], [24], [25], [26]]. Administering perturbation training, however, has not been fully integrated into the rehabilitation clinics as part of the ACL rehabilitation training in the United States. Moreover, manual perturbation training is limited to standing position and requires complete engagement, and requires one-on-one treatment by the therapist during the training [27].
Previous studies revealed that athletes alter joints kinematics by increasing joints stiffness when performing physical activities on compliant surfaces [[28], [29], [30], [31]]. Increased joint stiffness might be the result of offsetting the increase in compliance of surfaces and ensuring similar locomotion regardless of the changes in the compliant of the surface [29,31]. This effect was observed in athletes while performing hopping and running activities on compliant surfaces [[28], [29], [30]]. Integrating training programs with compliant surfaces into rehabilitation program after ACL-rupture may help patients with poor neuromuscular control improve dynamic knee stability.
Recently, an automated perturbation device has been developed with an embedded plate that moves vertically, simulating a variably compliant surface. Ultimately, performing high-demand physical activities that include hopping, jumping, and landing activities on a compliant surface may help patients with ACL-rupture to develop successful neuromuscular strategies that improve dynamic knee stability. Mechanical perturbation devices have been integrated into rehabilitation programs and have been shown to help with improve neuromuscular coordination [[32], [33], [34], [35], [36], [37]]. To this end, the effectiveness of administrating mechanical perturbation training with a compliant surface on the joint kinematics after ACL-rupture has not been investigated. Therefore, the aim of this study was to compare the effectiveness of administrating mechanical perturbation training with a compliant surface to manual perturbation training on gait kinematics after an acute ACL-rupture.
Section snippets
Methods
Twelve patients with an acute unilateral ACL rupture and between the ages of 14–55 were enrolled into this preliminary study. Four patients did not complete the study for commuting time, inability to commit the necessary time, experiencing pain during pre-training testing, or voluntarily. Full data set from eight patients who completed the study were included in the analysis of this study. These patients completed 10-sessions of mechanical perturbation training with a compliant surface
Results
No significant differences were found between groups for age, BMI, and time from injury to pre-testing (P>0.19). Additionally, no significant differences were found between groups for kinematic measures (p>0.08) (Table 1).
Discussion
The results of this study indicate that both treatment modes have effects on joints’ kinematics of the injured limb after ACL-rupture. However, mechanical training with a compliant surface induced different effects on joints’ kinematics of the injured limb compared to manual training after ACL-rupture. In general, mechanical group showed a trend of decreasing knee flexion motion, while manual perturbation training increased the angles of knee flexion angles during stance phase of walking.
The
Conclusion
Mechanical perturbation training with a compliant surface induced different effects on joint kinematics compared to manual perturbation training after ACL-rupture. Overall, manual perturbation training improved the hip joint alignment and increased the knee flexion angles, while mechanical perturbation training with a compliant surface decreased the angles of knee joint motion throughout stance phase. Implementing unanticipated mechanical perturbation training with a compliant surface into the
Contributes
ZN, DL, and LSM conceived the idea of this study. ZN and MF conducted the testing and training of patients. ZN analyzed and interpreted the data. All authors contributed to and interpretation of the data and writing of the manuscript. All authors contributed to the rebuttal and revised the final draft of this manuscript.
Conflict of interest
All authors certify that there were no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the manuscript.
Acknowledgments
This pilot study was funded by the National Institutes of Health (NIH/ Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)) (5R44 HD068054). All authors certify that there were no affiliations with or financial involvement in any organization or entity with a direct financial interest in the subject matter or materials discussed in the manuscript. We thank the University of Delaware Physical Therapy clinic (http://sites.udel.edu/ptclinic/) for facilitating
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