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2012 Publications

Does total knee arthroplasty change frontal plane knee biomechanics during gait?by Orishimo KF, Kremenic IJ, Deshmukh AJ, Nicholas SJ, Rodriguez JA. - last modified 2013-07-29 10:22
Clin Orthop Relat Res. 2012 Apr;470(4):1171-6. doi: 10.1007/s11999-011-2196-0. Epub 2011 Nov 29.

 

BACKGROUND:

Dynamic knee varus angle and adduction moments have been reported to be reduced after TKA. However, it is unclear whether this reduction is maintained long term.

QUESTIONS/PURPOSES:

We therefore asked whether (1) the dynamic knee adduction angle and moment remain reduced 1 year after TKA, (2) if changes in adduction moment are related to static alignment and varus angle during gait 6 months and 1 year after TKA, and (3) if these changes in loading pattern are related to changes in Knee Society scores.

METHODS:

We performed gait analysis on 15 patients (17 TKAs) before surgery and 6 months and 1 year after TKA. Weightbearing radiographs were used to assess coronal plane knee alignment.

RESULTS:

TKA corrected static knee alignment from 2.2° (2.5°) varus to 3.5° (2.7°) valgus at 6 months. Peak varus angle during gait was reduced from 9.7° (6.5°) to 3.6° (5.8°) at 6 months and 5.2° (7.6°) at 1 year. Peak adduction moment was reduced to 85% of the preoperative level at 6 months but increased to 94% of the preoperative level at 1 year. We observed a correlation between the increase in dynamic varus angle and increase in adduction moment from the 6-month to 1-year followups.

CONCLUSIONS:

TKA improves knee adduction moment at 6 months, but this effect is lost with time (1 year).

CLINICAL RELEVANCE:

Despite restoration of static knee alignment, knee adduction moment remains high presumably predisposing to medial polyethylene wear as noted by retrieval studies.