Carpal Joint Malalignment With Distal Radius Malunion and Factors in Correction After Distal Radius Osteotomy.

PURPOSE: There is a paucity of data regarding recommendations on when to correct for distal radius malunions and if the initial severity of the radiographic outcomes is correlated with the ability to correct to baseline. We evaluated the effects of distal radius corrective osteotomy on preoperative carpal joint malalignment resulting from distal radius malunions, correlated injury severity and osteotomy timing to radiographic outcomes, and developed a straightforward classification system for predicting radiocarpal and midcarpal maladaptive patterns.

METHODS: A retrospective review included 26 patients (27 wrists) who reported initial closed treatment for a distal radius fracture and who subsequently underwent a corrective osteotomy for malunion. Data included patient demographics, range of motion, preoperative fracture deformity, fracture deformity correction, and preoperative and postoperative radiographic measurements of the radiocarpal and midcarpal alignment patterns.

RESULTS: Of 27 dorsally angulated malunions, 16 were classified as type 1 midcarpal adaptation and 11 as type 2 radiocarpal adaptation. The midcarpal group showed significant improvements in distal radius and carpal alignment parameters after surgery, except for the ulnar variance. The radiocarpal group showed significant improvements in distal radius and carpal alignment parameters, except for the radiolunate angle, radioscaphoid angle, and capitolunate angle. The radiocarpal group exhibited an overall decrease in range of motion compared with that of the midcarpal group. Severity of the fracture and time taken from injury to corrective osteotomy correlated with the ability to correct carpal radiographic parameters in dorsally angulated malunions of the distal radius, especially beyond 40 weeks.

CONCLUSIONS: The severity of the initial fracture and time taken from injury to corrective osteotomy correlate with the ability to correct radiographic parameters in dorsally angulated malunions of the distal radius. Early correction of distal radius malunions is recommended, especially in radiocarpal malalignment patterns. A useful analysis for predicting midcarpal and radiocarpal adaptation patterns is the direct measurement of the distal articular surface of the radius to the lunate, termed the relative-radiolunate angle.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.