Reconstructive strategies for radioulnar dissociation: a biomechanical study

Radial head fracture combined with disruption of the soft-tissue restraints to proximal radial migration is defined as radioulnar dissociation. This injury often involves irreparable radial head fracture. When excised, management has emphasized the use of silicone implants to prevent proximal migration. However, concerns regarding silicone use led to the search for reconstructive alternatives. The purpose of this study was to compare reconstructive methods for radioulnar dissociation. Biomechanical testing to measure radial displacements under physiologic loads was performed on fresh-frozen cadavers after radial head resection. The central interosseous membrane (IOM) was disrupted to simulate radioulnar dissociation. This was followed by an orderly reconstructive sequence including radial head replacement with both silicone and titanium implants as well as a newly described flexible IOM reconstruction. Calculated stiffness values were used for comparison. Silicone implants provided no statistical improvement in forearm stiffness compared with the disrupted membrane state. Significant improvements were achieved with titanium implants and flexible IOM reconstruction, which restored stiffness to 89% and 94% of normal, respectively. No statistical differences were identified between these successful methods. Titanium implants combined with flexible reconstruction increased stiffness to 145% of normal. Further doubt is cast on the role of silicone implants in the management of radioulnar dissociation. Titanium implants and flexible IOM reconstruction appear to be wiser reconstructive choices.