RECONSTRUCTIVE STRATEGIES FOR RADIOULNAR DISSOCIATION - A BIOMECHANICAL STUDY

Radial head fracture combined with disruption of the soft-tissue restr aints to proximal radial migration is defined as radioulnar dissociati on, This injury often involves irreparable radial head fracture. When excised, management has emphasized the use of silicone implants to pre vent proximal migration. However, concerns regarding silicone use led to the search for reconstructive alternatives. The purpose of this stu dy was to compare reconstructive methods for radioulnar dissociation, Biomechanical testing to measure radial displacements under physiologi c loads was performed on fresh-frozen cadavers after radial head resec tion. The central interosseous membrane (IOM) was disrupted to simulat e radioulnar dissociation. This was followed by an orderly reconstruct ive sequence including radial head replacement with both silicone and titanium implants as well as a newly described flexible IOM reconstruc tion, Calculated stiffness values were used for comparison. Silicone i mplants provided no statistical improvement in forearm stiffness compa red with the disrupted membrane state, Significant improvements were a chieved with titanium implants and flexible IOM reconstruction, which restored stiffness to 89% and 94% of normal, respectively, No statisti cal differences were identified between these successful methods. Tita nium implants combined with flexible reconstruction increased stiffnes s to 145% of normal. Further doubt is cast on the role of silicone imp lants in the management of radioulnar dissociation, Titanium implants and flexible IOM reconstruction appear to be wiser reconstructive choi ces.