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Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_7 | Pages 48 - 48
1 Jul 2022
Blucher N Fletcher J Platt N Porteous A
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Abstract

Introduction

Controversy exists regarding the optimal tibial coronal alignment in total knee arthroplasty. Many believe navigation or robotics are required to set kinematic alignments or to ensure they remain within ‘safe’ limits e.g. maximum 5° varus on the tibia. Given most navigation or robotic systems require the surgeon to identify the ankle malleoli, this study aimed to radiographically analyse standardly used intra-operative landmarks around the ankle, assessing their value in achieving kinematic alignment / setting safety boundaries.

Materials and Methods

Long leg alignment radiographs were analysed independently by two orthopaedic surgeons at two time points, eight weeks apart. Angles were measured between the long axis of the tibia (TB) and: 1. lateral malleolus (TB-LM), 2. lateral border of the talus (TB-LT) and 3. medial aspect of the medial malleolus (TB-MM). Intra- and inter-rater reliabilities were assessed.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_1 | Pages 15 - 15
1 Jan 2014
Blucher N Holmes G Trinca D Kimani BM Bass A
Full Access

The aim of this study was to validate the SENIAM recommendations for surface electromyography placement(sEMG) over rectus femoris(RF) muscle in healthy children and in children with cerebral palsy(CP) during gait analysis and compare placement using these guidelines to using ultrasonography.

Methods & Results:

The study included 10 healthy children volunteers and 10 CP children volunteers, aged 8–12. All the CP children had spastic diplegia, were GMFCS levels I–II and had not previously undergone surgery.

RF electrodes were placed following SENIAM recommendations. RF was then identified by ultrasound. The distance between the lateral edge of RF and the position of the sEMG electrode as per SENIAM guidelines and the width of RF was measured, to the nearest millimetre. We considered ‘ideal electrode’ position to be at halfway between the edges of RF (i.e. 50%).

The mean percentage difference in distance from the ‘ideal electrode’ position as measured by ultrasound to electrode placement following SEMIAN guidelines was 2.7% in the healthy children group compared with 19.5% in the CP group. By performing unpaired t tests we showed that there was no significant difference between the mean electrode position using SEMIAN guidelines and ‘ideal electrode’ position in the healthy children (p=0.0531), however the mean electrode position using SEMIAN guidelines in the CP patients was significantly different from the ‘ideal electrode’ position (p=0.0001).

Conclusion:

SENIAM recommendations for sEMG electrode placement over RF muscle were validated in 10 healthy children. We showed that ultrasonography improved the accuracy of sEMG electrode placement in children with CP, who can exhibit anatomical variation due to their condition. Accurate electrode placement will ensure that a more accurate signal is recorded which may have a direct clinical bearing on the decision to proceed with surgical intervention.

Level of evidence: II