The measurement of collateral knee laxity using non-invasive computer-assisted technology

JV Clarke, AH Deakin, AC Nicol, F Picard

Research output: Contribution to journalArticle

Abstract

Computer-assisted technology has provided surgeons with intra-operative quantitative measurement tools that have led to the development of soft-tissue balancing algorithms based on surgeon-applied varus-valgus stress. Unfortunately these forces tend not to be standardised and the resultant algorithms may at best be surgeon-specific. Furthermore, these techniques are only available intra-operatively and rely on the rigid fixation of trackers to bone. The aim of this study was to develop a non-invasive computer-assisted measurement technique and assess the variation in collateral knee laxity measurements between different clinicians.An image-free navigation system was adapted for non-invasive use by developing external mountings for active infrared trackers. A leg model with rigid tracker mountings was designed and manufactured for comparison. Multiple kinematic registrations of alignment were made for both the model and the right leg of a volunteer to quantify the soft tissue artefacts. Repeatability of the system was assessed by performing two registration processes on eight volunteers. Collateral knee laxity was assessed on a single volunteer by 16 participants of varying experience each applying a maximum varus and valgus knee stress. Two surgeons performed repeated examinations to assess intra-observer variation.For repeated registrations of alignment, the SD of the non-invasive mounting (0.8°) was only a third higher than the leg model (0.6°) and the actual range was only 1° larger. The repeated alignment measurements on the volunteers showed a high level of agreement with an intraclass correlation coefficient of 0.93. Varus-valgus stress values showed poor inter-observer variation with a wide range of angles for both varus (1° to 7°) and valgus stress (0.5° to 5°). A Mann-Whitney test between the two sets of repeated tests showed that both varus stress and overall laxity were significantly different (p
LanguageEnglish
Pages388
Number of pages1
JournalJournal of Bone and Joint Surgery, British Volume
Volume93-B
Issue numberSupp III
Publication statusPublished - 1 Jul 2011

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Volunteers
Knee
Technology
Leg
Observer Variation
Biomechanical Phenomena
Artifacts
Bone and Bones
Surgeons

Keywords

  • Computer-assisted technology
  • knee laxity measurements
  • non-invasive measurement technique

Cite this

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The measurement of collateral knee laxity using non-invasive computer-assisted technology. / Clarke, JV; Deakin, AH; Nicol, AC; Picard, F.

In: Journal of Bone and Joint Surgery, British Volume , Vol. 93-B, No. Supp III, 01.07.2011, p. 388.

Research output: Contribution to journalArticle

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