Irreducible fractures of distal radius due to tendon interposition are uncommon injuries in adults. Almost all cases of irreducible distal radial fractures have been reported in children with a growing physeal plate. They have been attributed to interposition of various soft tissues including the flexor and extensor tendons [1]-[4].
Manoli [3] reported a case of distal radial epiphyseal injury complicated by entrapment of flexor digitorum profundus tendon causing difficulty in reduction. Extensor tendon interposition between the metaphysis and epiphysis of both the ulna and radius was reported by Karlsson et al [1]. Ooi et al [4] described two consecutive cases of Galeazzi-equivalent fracture in children associated with tendon interposition at the fracture site and reported good functional outcome after open reduction and internal fixation. Periosteal flap causing difficult fracture reduction in Salter Harris type II distal radial injury was reported by Lesko et al [3].
In our case the patient had attained skeletal maturity and sustained this fracture due to high velocity injury. The mechanism of injury due to fall from a motor bike, fracture of both distal radius and ulna, associated soft tissue disruption, and a sheer type fracture configuration of the radius would have caused rupture of the extensor retinaculum and consequent entrapment of the extensor pollicis longus tendon at the fracture site. This was identified by dorsal approach during open reduction. Release of the tendon resulted in satisfactory fracture reduction and follow-up radiographs showed good radiological evidence of union.