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Hamstring Co-Contraction in the Early Stage of Rehabilitation After Anterior Cruciate Ligament Reconstruction: A Longitudinal Study. Song Hongyun,Dai Xuesong,Li Jianhua,Zhu Sunan American journal of physical medicine & rehabilitation OBJECTIVE:Hamstring co-contraction may affect recovery from anterior cruciate ligament reconstruction. The aim of the study was to evaluate the changes in hamstring co-contraction during the early postoperative stages. DESIGN:Twenty-five patients with anterior cruciate ligament reconstruction were followed up for 1-3 mos postoperatively, during which the Lysholm and International Knee Documentation Committee questionnaires were completed and surface electromyograms were assessed during terminal knee extension maximum voluntary contraction and step-up tests. The integrated electromyogram of the tested muscles and co-contraction ratio were analyzed. RESULTS:Co-contraction ratio during terminal knee extension maximum voluntary contraction at 3 mos postoperatively was significantly less than that at 1 mo postoperatively (P < 0.0083), and it did not significantly differ from that of the uninvolved knee. In contrast, the co-contraction ratio during step-up was significantly higher at 2 and 3 mos postoperatively than that before surgery (P < 0.0167) and for the uninvolved knee (P < 0.05). Moreover, the postoperative hamstring co-contraction ratio in patients with a chronic injury was significantly higher during the step-up test than in patients with an early injury (P = 0.017). CONCLUSIONS:Hamstring co-contraction ratio during terminal knee extension maximum voluntary contraction recovers during the early postoperative stages. However, hamstring co-contraction ratio during step-up, which may be related to knee joint proprioception, remains high, particularly for patients with a chronic injury. CLINICAL TRIAL:ChiCTR-COC-17011167. 10.1097/PHM.0000000000000941
Somatosensory Function Influences Aberrant Gait Biomechanics Following Anterior Cruciate Ligament Reconstruction. Blackburn Jonathan T,Pietrosimone Brian,Spang Jeffrey T,Goodwin Jonathan S,Johnston Chris D Journal of orthopaedic research : official publication of the Orthopaedic Research Society Osteoarthritis is common following anterior cruciate ligament reconstruction (ALCR), and aberrant gait biomechanics are considered a primary contributor. Somatosensory dysfunction potentially alters gait biomechanics, but this association is unclear. Therefore, the purposes of this investigation were to compare somatosensory function between limbs and evaluate associations between somatosensory function and gait biomechanics linked to osteoarthritis development in individuals with ALCR. Seventy-three volunteers with ALCR participated. Gait biomechanics (peak vertical ground reaction force magnitude and loading rate, peak internal knee extension and valgus moments, peak knee flexion and varus angles, and quadriceps/hamstrings co-activation) were assessed as subjects walked at their preferred speed. The somatosensory function was assessed via joint position sense error (knee flexion) and vibratory perception threshold (femoral epicondyles, malleoli, and first metatarsal). Though somatosensory function did not differ between the ACLR and contralateral limbs, poorer joint position sense in the ACLR limb was associated with lower loading rates and internal knee extension moments, and greater co-activation. Poorer vibratory perception at the medial and lateral malleoli and first metatarsal head in the ACLR limb was associated with lower loading rates, greater internal knee valgus moments and varus angles, and greater co-activation. Poorer vibratory perception at the medial malleolus and first metatarsal head in the contralateral limb was associated with greater peak knee varus angles and internal knee valgus moments. These results suggest that future research evaluating rehabilitation approaches for improving somatosensory function is warranted as a potential approach for restoring normal gait biomechanics and reducing osteoarthritis risk. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:620-628, 2020. 10.1002/jor.24495
Comparison in Joint-Position Sense and Muscle Coactivation Between Anterior Cruciate Ligament-Deficient and Healthy Individuals. Suarez Tania,Laudani Luca,Giombini Arrigo,Saraceni Vincenzo Maria,Mariani Pier Paolo,Pigozzi Fabio,Macaluso Andrea Journal of sport rehabilitation CONTEXT:Tearing of the anterior cruciate ligament (ACL) may disrupt the ability to recognize the knee position in space during limb-repositioning tasks, which is referred to as joint-position sense (JPS). Impairments in JPS have been shown to be lower during active than passive repositioning tasks, thus suggesting that coactivation patterns of the muscles surrounding the knee might compensate for the disrupted JPS and ensure accurate limb repositioning in ACL-deficient individuals. OBJECTIVE:To investigate muscle coactivation patterns during JPS repositioning tasks in ACL-deficient and healthy individuals. DESIGN:Prospective observational study. SETTING:Functional assessment laboratory. PARTICIPANTS:8 men age 25 ± 8 y with isolated ACL rupture and 10 men age 30 ± 4 y with no history of knee injury. INTERVENTION:JPS was evaluated by means of an electrogoniometer in a sitting position during either passive or active joint-positioning and -repositioning tasks with a 40° target knee angle. MAIN OUTCOME MEASURES:Root mean square (RMS) of the surface electromyogram from the vastus lateralis and biceps femoris muscles was measured during active joint positioning and repositioning. RESULTS:Healthy participants showed a significant decrease in vastus lateralis RMS (-19%) and an increase in biceps femoris RMS (+26%) during joint repositioning compared with positioning. In contrast, ACL-deficient patients showed no modulation in muscle coactivation between joint positioning and repositioning, although they exhibited significantly lower RMS of the vastus lateralis (injured limb, -28%; uninjured limb, -21%) and higher RMS of the biceps femoris (injured limb, +19%; uninjured limb, +30%) than the healthy participants during joint positioning. CONCLUSIONS:The lack of modulation in muscle coactivation patterns between joint positioning and repositioning in ACL-deficient patients might be attributed to disrupted neural control after the injury-related loss of proprioceptive information. These results should be taken into account in the design of rehabilitation protocols with emphasis on muscle coactivation and JPS. 10-1123/jsr.2014-0267
Muscle co-contraction after anterior cruciate ligament reconstruction: Influence of functional level. Lustosa Lygia Paccini,Ocarino Juliana Melo,de Andrade Marco Antônio Percope,Pertence Antonio Eustáquio de Melo,Bittencourt Natalia Franco Netto,Fonseca Sérgio Teixeira Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology BACKGROUND:ACL reconstruction is recommended to improve function in subjects with ligament injuries. However, after surgery, some individuals are not able to return to their pre-injury functional level. The mechanisms related to this incapacity are not well understood. STUDY DESIGN:Cross-sectional study. METHODS:Co-contraction levels were assessed in individuals who returned to their pre-injury functional level and in 10 individuals who were not able to return to full activity after unilateral ACL reconstruction. Electromyography of the vastus lateralis and biceps femoris muscles before and after sudden perturbations applied during the stance phase of walking was used to calculate co-contraction. RESULTS:The involved limb had lower co-contraction pre-perturbation than the non-involved limb in both groups (p=0.049). The co-contraction level post-perturbation was significantly higher in the limited return group than in the full return group (p=0.03). CONCLUSION:Decreased co-contraction in the involved limb before perturbation may be caused by sensorial changes resulting from surgery or injury. Increased co-contraction levels observed in the limited return group after perturbation may be a compensatory mechanism to make up for possible decreased intrinsic stability of the knee joint. CLINICAL RELEVANCE:Increased co-contraction after perturbation does not contribute to knee stability. 10.1016/j.jelekin.2011.09.001
Study on three-dimensional kinematics and electromyography of ACL deficient knee participants wearing a functional knee brace during running. Théoret Daniel,Lamontagne Mario Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA This investigation examined the muscular activity and 3D knee joint kinematic changes of anterior cruciate ligament-deficient (ACLD) participants in the involved leg under bracing condition during running. Different adaptation strategies have been found between patients who can cope with the injury and patients who cannot. One of the expected changes can be the muscle activation characteristic of the injured knee during strenuous activity with and without a functional knee brace. Three-dimensional kinematic and electromyographical (EMG) data were collected from 11 participants for 10 consecutive gait cycles during running on a treadmill under both braced and unbraced conditions. Participants were administered the "Knee Outcome Survey Activities of Daily Living Scale" to distinguish functional and non-functional candidates. No significant differences on 3D kinematics and EMG data were noted between functional and non-functional participants, thus data analysis focused on comparisons of bracing conditions for one combined group. Bracing significantly reduced total range of motion in the frontal and transverse planes (P<0.05). Muscle activity at heel-strike showed a consistent trend to increase for the hamstrings and decrease for the quadriceps under the braced condition when compared to the unbraced condition. Our findings indicate that bracing the ACLD knee alters the kinematics of the injured leg while running. Tendencies toward reductions in quadriceps and increases in hamstrings activity at heel-strike indicate that bracing might have resulted in added stability of the injured knee. The adaptations to bracing found in this preliminary study further support the potential mechanical and proprioceptive contributions of the functional knee brace to protect the ACLD knee. 10.1007/s00167-006-0072-3