Impact of post-operative hip-knee-ankle angle changes on functional outcome of total knee arthroplasty: a prospective longitudinal study


  • Sukanya Palit Department of Anatomy, Jhargram Government Medical College and Hospital, Jhargram, West Bengal, India
  • Tapobrata Guha Roy Department of Community Medicine, R. G. Kar Medical College and Hospital, Kolkata, West Bengal, India



Total knee arthroplasty, Hip-knee-ankle angle, Coronal malalignment, Functional outcome, Mechanical axis


Background: Coronal malalignment as residual varus may have deleterious effects on functional outcomes of total knee arthroplasty. This study aimed at highlighting the impact of postoperative hip-knee-ankle (HKA) angle changes on the functional outcome of total knee arthroplasty.

Methods: 689 total knee arthroplasty (TKA) knees (from 386 patients) with varus postoperative HKA angle were included. HKA angle was measured on standing orthoscanograms. The knees were divided into 5 subgroups according to postoperative HKA angle as: neutral (0±3.0 degrees); mild (3.1-6.0 degrees); moderate (6.1-10.00 degrees); severe (10.1-5.0 degrees); very severe (>15.0 degrees). Functional outcome of TKA in these subgroups was observed by knee society score (KSS), knee society pain score (KSS-P), Oxford knee score (OKS), lower extremity functional scale (LEFS) at 6 months, 1 year, 2 years, 3 years. Statistical analysis was done by statistical package for social sciences (SPSS) version 16; Spearman’s correlation coefficient and Kruskall Wallis test was used to compare the functional outcome of TKA between COHORTs.

Results: 69 knees were present in the mild varus cohort (mean: -1.92), 223 knees in the moderate varus COHORT (mean: -4.77), 260 knees in the moderate varus COHORT (mean: -7.86), 121 knees in the severe varus COHORT (mean: -11.60) and 16 knees in the very severe varus COHORT (mean: -16.54). Mild to moderate varus knees were maximum, but no significant difference in functional outcome between these COHORTs was found by correlation analysis and Kruskall Wallis test.

Conclusions: Changes in postoperative HKA angle (coronal alignment) has no significant impact on functional outcome of TKA.



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