Research Recipients

Research Award Details

2015 - POSNA Research Grant

Return to Play and Mid-Term Assessment of Asymmetries Using 3D Motion Analysis Post ACL Reconstruction in Adolescents

Grant Recipient: Matthew Milewski, MD - Clinical Research

Co-Investigators: Sylvia Ounpuu, MSc

Institution:: Connecticut Childrens Med. Ctr.

Presentations & Publications:: Presentations:
1. Giampetruzzi N, et al. Asymmetric knee kinematics and kinetics after ACL reconstruction in adolescent athletes. American Physical Therapy Association (APTA) Combined Sections Meeting. Anaheim, CA. February 17-20th. 2016.

2. Garibay E. et al. Short and mid-term knee kinematic and kinetic symmetry during jumping and hopping tasks after ACL repair. Gait and Clinical Movement Analysis Society (GCMAS) Annual Meeting. Memphis, TN. May 17-20th 2016.

Additional Information:: Summary
The incidence of anterior cruciate ligament (ACL) injury has reached epidemic levels in adolescent athletes who have a particularly high risk of repeat injury. In many cases surgical ACL repair (ACLR) is performed to allow return to physical activity. A critical decision point following surgery is to determine when the athlete is ready to return to play (RTP). The basis of the decision to RTP is symmetry in function and strength between the healthy uninjured knee and the ACLR knee. The purpose of this study was to compare the differences between the healthy and ACLR knees during a variety of tasks including running, hopping and jumping (functional assessment) in terms of the motion and loads on the knee joint in a group of adolescent athletes (15 adolescents). To assist in the interpretation of the difference between the ACLR and healthy knees, healthy adolescents (control group of 15 adolescents) completed the same protocol. To understand if the asymmetries noticed at the initial RTP evaluation change over time, a subgroup of athletes returned to complete the same protocol at about 1 1/5 years following RTP approval. Comprehensive motion analysis techniques were used to measure the 3D movement and loads on the knees during these tasks.

The findings show that a comparison between the mean knee parameters of the ACLR and healthy knees shows increased knee bending and loads on the healthy knee in comparison to the ACLR knee at the time to RTP. A similar analysis for the control group showed less difference between the preferred and non-preferred sides for the same mean knee measures. The differences between sides are more significant for loading parameters than peak knee flexion. These findings suggest that the adolescent athlete at the time of approved RTS may show ongoing asymmetries in knee function.

There were however, significant variations in the assessment of symmetry between sides in both patients and controls when evaluating individual subjects. This was assessed by looking at the frequency of side to side differences that were > 10%. This data showed that peak knee flexion during landing was less likely to show >10% difference between sides in both the ACLR patients and healthy controls in comparison to the knee loading parameters. This finding suggests that a visual assessment of the knee bending may not provide the full picture of landing asymmetry. There were also more subjects who had greater than 10% asymmetry in the control group versus the patient group with respect to all knee parameters. However, this was dependent on the parameter assessed and on the functional assessment task with no specific pattern of findings. Further analysis will be needed to better understand these results.

The subset of patients (8) who came back for a second analysis 2 years following ACLR showed a variety of findings at the initial assessment with symmetry (<10% difference) between ACLR and healthy knee depending on the patient, measurement and functional task. The change in symmetry over time also varied depending on the measurement and functional task. These preliminary results do suggest that the majority of patients do not show increased asymmetry over time. However, in some functional tasks this does occur.

The overall findings suggest that the assessment of symmetry of knee function needs to consider the functional task being evaluated. There was substantial variability in movement from trial to trial especially in unilateral tasks that may limit the use of a symmetry measure as an assessment of optimal function. These preliminary findings, when merged with a larger data set currently being collected, will provide insight into the role of the objective measurement of knee symmetry in helping RTP decisions. Future analysis will also include the assessment of adjacent joints to better understand other aspects of landing asymmetry such as landing strategy differences between sides.