Robert J Butler1, Boyi Dai, Nikki Huffman, William E Garrett, Robin M Queen. 1. *Department of Orthopaedic Surgery, Doctor Division of Physical Therapy, Duke University, Durham, North Carolina; †Michael W. Krzyzewski Human Performance Laboratory, Department of Orthopaedic Surgery, Duke University, Durham, North Carolina; ‡Division of Kinesiology and Health, University of Wyoming, Laramie, Wyoming; §Division of PT/OT Services, Duke University Health System, Durham, North Carolina; ¶Department of Orthopaedic Surgery, Duke University, Durham, North Carolina; and ‖Biomedical Engineering and Mechanics, Kevin P. Granata Biomechanics Lab, Virginia Tech, Blacksburg, Virginia.
Abstract
OBJECTIVE: To examine how landing mechanics change in patients after anterior cruciate ligament reconstruction (ACL-R) between 6 months and 12 months after surgery. DESIGN: Case-series. SETTING: Laboratory. PARTICIPANTS: Fifteen adolescent patients after ACL-R participated. INTERVENTIONS: Lower extremity three-dimensional motion analysis was conducted during a bilateral stop jump task in patients at 6 and 12 months after ACL-R. Joint kinematic and kinetic data, in addition to ground reaction forces, were collected at each time point. MAIN OUTCOME MEASURES: During the stop jump landing, the peak joint moments and the initial and peak joint motion at the ankle, knee, and hip were examined. The peak vertical ground reaction force was also examined. RESULTS: Interactions were observed for both the peak knee (P = 0.03) and hip extension moment (P = 0.07). However, only the hip extension moment was symmetrical level at 12 months. Statistically significant (P < 0.05) side-to-side differences existed for the ankle angle at initial contact, peak plantarflexion moment, peak hip flexion angle, and peak impact vertical ground reaction force independent of time. CONCLUSIONS: The findings of this study suggest that sagittal plane moments at the knee and hip demonstrate an increase in symmetry between 6 months and 1 year after ACL-R surgery, however, symmetry of the knee extension moment is not established by 12 months after surgery. The lack of change in the variables across time was unexpected. As a result, it is inappropriate to expect a change in landing mechanics solely as a result of time alone after discharge from rehabilitation.
OBJECTIVE: To examine how landing mechanics change in patients after anterior cruciate ligament reconstruction (ACL-R) between 6 months and 12 months after surgery. DESIGN: Case-series. SETTING: Laboratory. PARTICIPANTS: Fifteen adolescent patients after ACL-R participated. INTERVENTIONS: Lower extremity three-dimensional motion analysis was conducted during a bilateral stop jump task in patients at 6 and 12 months after ACL-R. Joint kinematic and kinetic data, in addition to ground reaction forces, were collected at each time point. MAIN OUTCOME MEASURES: During the stop jump landing, the peak joint moments and the initial and peak joint motion at the ankle, knee, and hip were examined. The peak vertical ground reaction force was also examined. RESULTS: Interactions were observed for both the peak knee (P = 0.03) and hip extension moment (P = 0.07). However, only the hip extension moment was symmetrical level at 12 months. Statistically significant (P < 0.05) side-to-side differences existed for the ankle angle at initial contact, peak plantarflexion moment, peak hip flexion angle, and peak impact vertical ground reaction force independent of time. CONCLUSIONS: The findings of this study suggest that sagittal plane moments at the knee and hip demonstrate an increase in symmetry between 6 months and 1 year after ACL-R surgery, however, symmetry of the knee extension moment is not established by 12 months after surgery. The lack of change in the variables across time was unexpected. As a result, it is inappropriate to expect a change in landing mechanics solely as a result of time alone after discharge from rehabilitation.