Orthopaedic Biomechanics

Orthopaedic Biomechanics

The service undertook a number of collaborative projects with the Department of Orthopaedic Surgery during the 1980s.

One of these projects, an investigation into the effect of later fracture shift, led to the design and construction of a bone torsion testing machine. The output from the machine’s strain gauge amplifier was sampled using the analogue input of a BBC model B microcomputer. The microcomputer was also used to analyse the resulting data.

Another project was to design an external fracture fixation system that would be easier to fit in the operating theatre and allow for both compression and distraction. Work was also carried out on the understanding the mechanical properties of tendon sutures, developing mathematical models of fracture fixators, and investigating the feasibility of using foil strain gauges on fracture fixators.

A surgical tube saw was designed during the mid-1980s in cooperation with a local orthopaedic surgeon to improve the technique of epiphysiodesis. Epiphysiodesis is the method used to correct moderate, 2 to 5 cm, discrepancies in leg length during childhood. The tube saw offered significant advantages over other existing methods at that time. It enabled a shorter and less traumatic surgical procedure, resulted in a reduced recovery period with no need for the leg to be immobilised in plaster and produced superior cosmetic outcome. The relatively simple equipment was developed over a 10 year period. It continued to be used in surgery for around another 10 years.

Edinburgh’s tradition of research and development in the area of orthopaedic biomechanics continues to this day with the work of the University of Edinburgh’s Department of Orthopaedic Surgery at its Edinburgh Orthopaedic Engineering Centre.

Selected Further Reading

Draper ERC, Strachan RK.

A machine for measuring the torsional properties of long bones.
Engineering in Medicine 1988;17(2):83.
[Abstract; Conference on Rehabilitation and Orthopaedic Engineering, Belfast, 27 March 1987].

Hullin MG, McMaster MJ, Draper ERC, Duff ES.
The effect of Luque segmental sublaminar instrumentation on the rib hump in idiopathic scoliosis.
Spine 1991;16(4):402-408.

Macnicol MF, Krishnan J, Draper ERC.
Epiphyseodesis using a cannulated tube saw: comparison with the Phemister technique.
Journal of Pediatric Orthopaedics Part B 1993;2(1):70-4.

Macnicol MF, Farley RD.
A new cannulated tube saw for epiphysiodesis.
Orthopaedic Product News 1998;Jul/Aug/Sep:18-19.

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Written & compiled by Dr Michael J Dolan, SMART Centre, NHS Lothian, Edinburgh.

First published 15th March 2013. Last updated 24th June 2014. Version 1.1.