A comparison of radiological and computer navigation measurements of lower limb coronal alignment before and after total knee replacement

N. M J Willcox, J. V. Clarke, B. R K Smith, A. H. Deakin, K. Deep

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32 Citations (Scopus)


We compared lower limb coronal alignment measurements obtained pre- and postoperatively with long-leg radiographs and computer navigation in patients undergoing primary total knee replacement (TKR). A series of 185 patients had their pre- and postimplant radiological and computer-navigation system measurements of coronal alignment compared using the Bland-Altman method. The study included 81 men and 104 women with a mean age of 68.5 years (32 to 87) and a mean body mass index of 31.7 kg/m2 (19 to 49). Pre-implant Bland-Altman limits of agreement were -9.4° to 8.6° with a repeatability coefficient of 9.0°. The Bland-Altman plot showed a tendency for the radiological measurement to indicate a higher level of pre-operative deformity than the corresponding navigation measurement. Post-implant limits of agreement were -5.0° to 5.4° with a repeatability coefficient of 5.2°. The tendency for valgus knees to have greater deformity on the radiograph was still seen, but was weaker for varus knees. The alignment seen or measured intra-operatively during TKR is not necessarily the same as the deformity seen on a standing long-leg radiograph either pre- or post-operatively. Further investigation into the effect of weight-bearing and surgical exposure of the joint on the mechanical femorotibial angle is required to enable the most appropriate intra-operative alignment to be selected. 

Original languageEnglish
Pages (from-to)1234-1240
Number of pages7
JournalJournal of Bone and Joint Surgery, British Volume
Volume94 B
Issue number9
Publication statusPublished - 1 Sep 2012


  • adult
  • article
  • body mass
  • female
  • human
  • infant
  • leg
  • leg malformation
  • major clinical study
  • male
  • priority journal
  • total knee replacement
  • valgus deformity
  • valgus knee
  • varus deformity
  • varus knee
  • weight bearing
  • X ray film

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