Introduction: Intra-articular malunion with step off and gap formation is claimed to be crucial for radiocarpal degeneration. In addition to well-defined intraarticular malunion, the shape of the distal radius is important for unaffected wrist function. In typical intra-articular fracture patterns with a dorsoulnar and palmar ulnar fragment, alterations of the shape of the articular surface, in a kind of a cavity, without obvious step off can be observed. The aim of the present study is to determine the residual articular deformity following intra-articular radius fractures and to analyze their impact on the final clinical and radiological outcome.
Materials and methods: Eighty one patients with dorsally displaced distal intraarticular radius fractures were followed up for a mean period of 9 years. Surgical treatment of all patients included open reduction, plate fixation and corticocancellous bone grafting. Radiological measurements included palmar tilt, radial inclination and radial shortening as defined by ulnar variance, intra-articular Stepps and the measurement of the anteroposterior distance of the radial joint surface. Clinical assessment included active range of motion (ARM) of the wrist, pain according to a visual analogue scale (VAS), grip power, working ability, Disability of Arm, Shoulder and Hand Score (DASH Score).
Results: Articular malunion in the form of a cavity in the sagittal plane measured 4.8 mm, 1.3 mm more than on the non-injured side. Anteroposterior distance measured 20.6 mm, 2.1 mm more than on the non-injured side. Articular step-off and gap was noticed in 11 patients. At the final follow-up examination, there was a significant difference in articular cavity depth and the anteroposterior distance between arthritis stage I and II. Arthritis stage was associated with the range of motion (ROM) in the sagittal plane, but had no significant influence on the DASH, pain level, grip strength and ROM in the frontal plane.
Conclusion: ORIF leads to predictable results in the restoration of length and form of the distal radius. Increasing the articular cavity depth should be avoided to prevent degenerative arthritis at the radiocarpal joint at long-term follow-up visits.