Abstract
Introduction: An ideal screw for subtalar fusion would be designed such that screw thread length in the distal bone would be maximised but without distal perforation, whilst having no threads across the fusion site that would inhibit compression.
Method: Radiographs and clinical assessment of 100 patients who had undergone subtalar fusion were analysed and correlated with the presence or absence of non-union.
In addition, using the characteristics of the inserted screw as a scaleable marker, it was calculated what would have been the optimum length of screw thread in order to maximise screw thread length in the target bone whilst preventing the screw threads being across the fusion site.
Results: There is no correlation between the presence of screw threads across the fusion site and non-union.
Currently available screws have thread lengths that are either too long (breaching the fusion site) or too short for ideal fixation and we propose a different thread length to those currently available.
However, even with current screws, we found no correlation between thread length, thread positioning across the fusion site and non-union.
Correspondence should be addressed to: D. Singh, BOFAS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
