All of the following can be the complications of a Malunited Colles fracture, EXCEPT:

olles fracture refers to a fracture dislocation of the inferior radioulnar joint. It is associated with a classical dinner fork deformity. This fracture is associated with all the complications mentioned in the question except the rupture of flexor pollicis tendon. Secondary to colles fracture there is a rupture of extensor pollicis tendon. This occur due to the attrition of the tendon as it glides over the sharp fracture surfaces. It usually occurs 4-6 weeks after the fracture. Ref: Text and Atlas of Complications of Fractures By John Ebneza, Page 50.