Abstract
Aim: To measure the percentage increase in length of the donor graft during rehabilitation from 0 degrees to 120 degrees of elbow flexion and to compare this with the end range strength.
Method: During the troids procedure four metal skin-clips were inserted at the proximal and distal margins of the proximal and distal tibialis posterior tendon weaves creating three intervals for measurement. Lateral x-rays of the humerus with the tube distance at 100cms were taken after five weeks of plaster immobilisation before elbow flexion commenced at a maximum rate of 15 degrees per week. X-rays were repeated when 60 degrees and 120 degrees of flexion obtained and when possible six months post surgery. Elbow torque was measured by the Troidometer throughout the range of motion at similar time intervals. Interval measurement was by a Vidar VRX 12 digital scanner. The Paired T test was used for statistical analysis.
Results: Sixteen arms (nine patients) were entered into the study but complete rehabilitation data were available from only 12 arms and late data from only four. There was a 12.3% average increase between 0 degrees and 60 degrees (range six to 20.6 degrees) and a further 3% increase from 60 degrees to 120 degrees (range −6 degrees to 21 degrees). The most stretch occurred in the distal segment and in bilateral arms the percentage of stretch was similar for each arm. There was no correlation between the percentage of stretch and end range torque or lag.
Conclusions: The Troids transfer restores elbow extension for tetraplegics but an extensor lag often develops which is thought to be from stretching of the donor tendon graft. This study confirmed that tendon stretch occurs but there was wide variation among individuals although similar for each arm in bilateral procedures. An average of 75% of stretch occurred during the 0 degrees to 60 degrees mobilisation. We concluded that tendon stretch is inevitable but is not a major contributor to end range weakness or lag.
The abstracts were prepared by Professor A. J. Thurston. Correspondence should be addressed to him at the Department of Surgery, Wellington School of Medicine, PO Box 7343, Wellington South, New Zealand
