There is a higher risk that the tendon of extensor pollicis longus will rupture in undisplaced Colles' type of fracture than in those which are displaced. This difference in incidence is due to the integrity of the extensor retinaculum in undisplaced Colles' type of fracture causing the tendon to be held tight against the fracture callus in the floor of the tunnel which may result in an attrition rupture. In the displaced Colles' fracture the extensor retinaculum is torn from the bone and thus permits the tendon to escape from contact with the fracture site.

Twenty-two patients who underwent an Ellison extra-articular tenodesis for anterolateral instability of the knee, performed by one surgeon (SCC), have been reviewed after a mean follow-up of 59 months. Seventy-seven per cent had a good or excellent result enabling them to return to their pre-injury level of sport. These results compare very favourably with intra-articular repair but are not associated with such severe complications.