Total Distal Radioulnar Joint Research Articles

Implant Arthroplasty for the Distal Radioulnar Joint

The distal radioulnar joint (DRUJ) is a weight-bearing joint; the ulnar head is frequently excised either totally or partially and in some cases is fused because of degenerative, rheumatoid, or posttraumatic arthritis and treated with a "salvage procedure." The result of these procedures is the inability of those patients to lift even minor weight. Articles about these procedures report the ability to pronate and supinate, but they rarely discuss grip strength or lifting capacity. We present an alternative to the salvage procedures that allows full range of motions as well as the ability to grip and lift weights encountered in daily living, such as a gallon of milk. The Aptis total DRUJ replacement prosthesis (Aptis Medical, Louisville, KY), a bipolar self-stabilizing DRUJ endoprosthesis, restores the forearm function. The technique of implantation is presented here.

A STUDY OF FUNCTIONAL OUTCOMES FOLLOWING IMPLANTATION OF A TOTAL DISTAL RADIOULNAR JOINT PROSTHESIS

This paper reports a long-term follow-up measuring pain, range of motion and weight-bearing ability, following implantation of a total distal radioulnar joint prosthesis. This prosthesis differs from excision arthroplasties and ulnar head replacements by replacing all three components of the distal radioulnar joint, viz. the sigmoid notch, the ulnar head and the triangular fibrocartilage. The design allows longitudinal migration of the radius throughout pronation and supination, as well as load bearing of the wrist. Thirty-one patients receiving the prosthesis returned or were interviewed by telephone at a mean of 5.9 (range 4-9) years. Pronation increased from a mean of 65.5 degrees (range 5-90 degrees ) to 74 degrees (range 20-90 degrees ) and supination from 53 degrees (range 5-90 degrees ) to 70 degrees (range 20-90 degrees ) while greatly diminishing and/or eliminating pain. Grip increased from a mean of 10 kg (22 lbs) to 24 kg (52 lbs). Weight bearing was restored or increased in 29 of 31 patients.

WITHDRAWN: A study of functional outcomes following implantation of a total distal radioulnar joint prosthesis

WITHDRAWN: A study of functional outcomes following implantation of a total distal radioulnar joint prosthesis

Does the orientation of the distal radioulnar joint influence the force in the joint and the tension in the interosseous membrane?

Objective. To investigate the effect of change in the orientation of the distal radioulnar joint on the force in the joint and the strain in the interosseous membrane. Design. Biomechanical study in fresh frozen cadavers. Background. The articular surfaces of the distal radioulnar joint may be orientated in parallel with the long axis of the forearm (a Type I joint) or at an oblique angle opening distally to the ulnar side (a Type II joint). Methods. Three cadaveric upper limbs were held on a custom built frame allowing measured rotation and axial loading across the wrist. Measurements of force in the distal radioulnar joint and strain in the interosseous membrane were taken and repeated after replacement of the distal radioulnar joint with prosthetic Type I and Type II joints. Findings. The force in the joint and the strain in the interosseous membrane increased with increasing load across the wrist ( P < 0.0001). The force in the Type I joint was reduced compared to the normal or Type II joint. This difference was greater with increasing load and was significant at 8 kg ( P < 0.001). The strain in the interosseous membrane was maximal at neutral forearm rotation and decreased with increasing pronation and supination. Interpretation. The force in the joint is greater with the Type II distal radioulnar joint. We believe this compressive force increases joint stability and this orientation of the articular surfaces should be considered in the design of a total distal radioulnar joint arthroplasty.