Subtle alterations in whole body mechanics during gait following anterior cruciate ligament reconstruction.
Paige E Lin, Susan M Sigward
PMID 30616179WHAT IT FOUND
In 20 people after ACL reconstruction, even when gait looked normal, the surgical limb showed reduced knee motion, lower knee extension moment, smaller backward ground reaction force, and slower forward body movement during early stance.
Key findings
01The surgical limb showed less knee range of motion, lower knee extension moment, smaller backward ground reaction force, and lower forward body movement speed than the non-surgical limb.
02Vertical ground reaction force, lowest center of mass position, and vertical center of mass velocity did not differ between limbs.
03The surgical limb showed different timing patterns: less anti-phase and more in-phase coordination of body movement speed, and less in-phase coordination of ground reaction force.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study included only 20 people at a single time point, so it cannot show how these differences change over time or whether they matter for symptoms, re-injury, or function. The researchers assumed the non-surgical limb represents normal gait mechanics, but they state this may not be accurate. Some participants had previous ACL reconstruction in the other or same knee, and meniscal injuries were included, so the sample was not a clean single-ACL reconstruction group. The center of mass model used trunk and lower extremity segments and accounted for 82% of body mass, but did not include arms and head. Small differences in center of mass velocity may be affected by marker placement and motion capture error, although the authors say timing differences across consecutive points are less likely to be influenced by marker error. The study did not test an intervention, so it cannot tell therapists whether these findings should change treatment.
Declared interests
The authors declared no conflicts of interest. The article metadata lists NIH extramural research support.
The easy way to misread this
Do not conclude that these lab gait differences prove a patient's visually normal gait is clinically abnormal. The study did not test a treatment, did not follow patients over time, and did not link the findings to symptoms, re-injury, or function.