The effect of tibiotalar alignment on coronal plane mechanics following total ankle replacement.
BACKGROUND
Gait mechanics following total ankle replacement (TAR) have reported improved ankle motion following surgery. However, no studies have addressed the impact of preoperative radiographic tibiotalar alignment on post-TAR gait mechanics. We therefore investigated whether preoperative tibiotalar alignment (varus, valgus, or neutral) resulted in significantly different coronal plane mechanics or ground reaction forces post-TAR.


METHODS
We conducted a non-randomized study of 93 consecutive end-stage ankle arthritis patients. Standard weight-bearing radiographs were obtained preoperatively to categorize patients as having neutral (±4°), varus (≥5° of varus), or valgus (≥5° of valgus) coronal plane tibiotalar alignment. All patients underwent a standard walking assessment including three-dimensional lower extremity kinetics and kinematics preoperatively, 12 and 24 months postoperatively.


RESULTS
A significant group by time interaction was observed for the propulsive vertical ground reaction force (vGRF), coronal plane hip range of motion (ROM) and the peak hip abduction moment. The valgus group demonstrated an increase in the peak knee adduction angle and knee adduction angle at heel strike when compared to the other groups. Coronal plane ankle ROM, knee and hip angles at heel strike, and the peak hip angle exhibited significant increases across time. Peak ankle inversion moment, peak knee abduction moment and the weight acceptance vGRF also exhibited significant increases across time. Neutral ankle alignment was achieved for all patients by 2 years following TAR.


CONCLUSIONS
Restoration of neutral ankle alignment at the time of TAR in patients with preoperative varus or valgus tibiotalar alignment resulted in biomechanics similar to those of patients with neutral preoperative tibiotalar alignment by 24-month follow-up.
['Grier|A Jordan|AJ|', 'Schmitt|Abigail C|AC|', 'Adams|Samuel B|SB|', 'Queen|Robin M|RM|']
D000328:Adult D000843:Ankle Joint D058737:Arthroplasty, Replacement, Ankle D001696:Biomechanical Phenomena D005260:Female D005684:Gait D006801:Humans D008297:Male D008875:Middle Aged D010003:Osteoarthritis D011184:Postoperative Period D016059:Range of Motion, Articular D012189:Retrospective Studies D013628:Talus D013977:Tibia D016896:Treatment Outcome D016474:Weight-Bearing
Tibiotalar alignment Total ankle replacement Outcomes Walking mechanics