Gait mechanics in chronic ACL deficiency and subsequent repair.

OBJECTIVE To determine how normal gait patterns may change as a result of chronic anterior cruciate ligament deficiency and subsequent reconstructive surgery. DESIGN Gait testing of 10 chronic anterior cruciate ligament deficient subjects prior to and 3 months following reconstructive surgery, and 10 uninjured controls. BACKGROUND There is controversy whether persons with chronic anterior cruciate ligament deficiency develop a "quadriceps avoidance" pattern and how anterior cruciate ligament reconstructive surgery influences gait mechanics in these same individuals. METHODS Gait analysis was employed to determine kinematic, kinetic, and muscle Electromyographic data. RESULTS Prior to surgery, no anterior cruciate ligament deficient subject exhibited a quadriceps avoidance pattern. Following surgery, the subjects exhibited a significantly greater knee extensor moment during early stance as compared to the control group. Prior to and following surgery, anterior cruciate ligament deficient subjects demonstrated a significantly greater hip extensor moment possibly to reduce anterior tibial translation. CONCLUSIONS; These data suggest that (1) development of a quadriceps avoidance pattern is less common than previously reported, (2) anterior cruciate ligament deficient subjects accommodate through alterations of hip joint mechanics, (3) surgical repair significantly alters lower extremity gait patterns, and (4) re-establishment of pre-injury gait patterns takes longer than 3 months to occur. RELEVANCE The results suggest that chronic anterior cruciate ligament deficient subjects do not exhibit a quadriceps avoidance gait pattern. Surgical intervention significantly alters lower extremity gait mechanics in a population that has accommodated to anterior cruciate ligament deficiency.