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Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_14 | Pages 2 - 2
1 Mar 2013
Firth G McMullan M Chin T Graham H
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Purpose of Study

Lengthening of the gastrocsoleus for equinus deformity is commonly performed in orthopaedic surgery. The aim of this study was to describe the precise details of each surgical procedure and assess each biomechanically in cadaver models.

Description of Methods

The surgical anatomy of the gastrocsoleus was investigated and standardized approaches were developed for the procedures described by Baumann, Strayer, Vulpius, Baker, Hoke and White. The biomechanical characteristics of these six procedures were then compared, in three randomized trials, in formalin preserved, human cadaver legs. The lengthening procedures were performed and a measured dorsiflexion force was applied across the metatarsal heads using a torque dynamometer. Lengthening of the gastrocsoleus was measured directly, by measuring the gap between the ends of the fascia or tendon.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXVIII | Pages 183 - 183
1 Sep 2012
Amin A Sproule JA Chin T Daniels TR Younger AS Boyd G Glazebrook M
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Purpose

Total Ankle Replacement (TAR) is increasingly being offered to patients as an alternative to arthrodesis for the operative management of debilitating end-stage ankle arthritis. The Mobility Total Ankle System is a third-generation design consisting of a three component, cementless, unconstrained, mobile-bearing prosthesis. This study reports the early results of a multi-centre prospective study of the Mobility prosthesis. This is the first such report by independent researchers.

Method

The senior authors implanted 86 consecutive Mobility prostheses. The underlying diagnosis was primary OA in 24 ankles, secondary OA in 47 ankles and inflammatory arthritis in 15 ankles. There were 41 males (Mean age 67 / Range 51–87) and 44 females (Mean age 60 / Range 29–72). The mean BMI was 28 (Range 22–36) for males, and 28 (Range 20–39) for females. Previous ankle operations were performed in 24 patients, 22 of which were for fracture fixation.

Ankles were classified according to the COFAS end-stage ankle arthritis classification system. Coronal plane deformity was quantified pre-operatively. Clinical outcome was assessed using the AOFAS hindfoot score. Radiological assessment was performed from weight-bearing radiographs, documenting post-operative alignment, osseous integration, edge-loading and heterotopic bone formation. The mean follow-up time was 40 months (Range 30–60).

Survival analysis was calculated according to the Kaplan-Meier method. Failure was defined as exchange of any component of the TAR, arthrodesis or amputation.


Orthopaedic Proceedings
Vol. 87-B, Issue SUPP_III | Pages 313 - 314
1 Sep 2005
Graham H Altuntas A Selber P Chin T Palamara J Wolfe R Eizenberg N
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Introduction and Aims: We investigated the hypothesis that the effects of muscle-tendon surgery could be controlled or ‘dosed’ by varying the location of intramuscular tenotomy (IMT) or fascial striping within the muscle-tendon unit (MTU). We performed a series of randomised trials in paired cadaver MTUs of tibialis posterior, semitendinosus, gracilis and semimembranosus.

Method: Following dissection of 10 paired cadaver MTUs of the above-mentioned muscles, we performed a series of randomised trials in which each pair of MTUs received a low or high IMT. ‘Low IMT’ was defined as an IMT performed two centimetres proximal to the distal musculotendinous junction. ‘High IMT’ was performed two centimetres distal to the start of the first tendinous fibres in the proximal muscle belly. The force-length characteristics were then determined by tensile load testing until failure on an Instron machine. The load and lengthening at failure for each pair of MTUs were compared by paired t test.

Results: As expected, there were significant differences in the load versus length curves for different muscles and for different simulated surgeries (IMT versus fascial striping). The mean load at failure was significantly lower for all low IMTs compared to high IMTs in all MTUs tested e.g. tibialis posterior: mean difference low versus high = 13N (95% CI 6.8, 19.2 p< 0.001). The lengthening at failure was also greater for low IMTs than for high IMTs. The difference reached statistical significance only in tibialis posterior.

Conclusions: The site of the intramuscular surgery or fascial striping has a direct bearing on the force versus lengthening curve. We hypothesise that the same principle applies during muscle tendon surgery in children with spastic contractures and that it may be possible to graduate surgical lengthening, according to the correction required.