Lower limb biomechanics before and after anterior cruciate ligament reconstruction: A systematic review

This review aimed to synthesise the findings of literature that have assessed the changes in lower limb biomechanics following anterior cruciate ligament (ACL) reconstructive surgery. Systematic searches of CINHAL, MEDLINE, SCOPUS, and SPORTDiscus databases were run. All included studies had presented biomechanical variables pre- and post-surgery for the same participants. Articles were categorised by the analysed movement, and effect sizes were calculated. Fifty-four studies met the inclusion criteria, providing data on gait (n = 31), balance (n = 12), joint position sense (n = 5), stair ambulation (n = 4), pivoting (n = 6), and landing (n = 5). Measures of balance performance and joint position sense showed improvements from pre- to post-surgery. Changes in joint kinematics were inconsistent between studies, however increased knee flexion excursion, and reduced tibial anterior translation and internal rotation post reconstruction were identified. Joint kinetics reduced in magnitude in the early stages after surgery (≤5 weeks), then increased later in recovery (≥24 weeks). Risk of bias assessment identified most articles had a moderate or high risk (low = 5; moderate = 21; high = 11) resulting from participant retention and surgical intervention differences. The results of the review identified that although lower limb biomechanics did alter following reconstruction, few variables provided consistent results across studies and tasks. The low methodological quality of some articles may have contributed to these inconsistent findings. Alternatively, differences across studies may have resulted from individual coping strategies of participants that have previously been suggested to be present before reconstructive surgery, and future research should look to explore individual coping strategies to ACL reconstruction.