Radial longitudinal deficiency III and IV present as a short upper limb, functional elbow, and wrist with severe radial and palmar angulation, where the carpus articulates with the radial and palmar edge of the ulna, allowing limited mobility in a nonfunctional position. Surgical treatment aims to correct radial angulation and flexed carpal position, often altering carpal positioning over the distal ulna and impacting wrist mobility. In addition, fixation through distal ulnar epiphysis affects its growth. Although these procedures improve appearance, functionality remains suboptimal. This study describes a novel ulnar osteotomy and extensor carpi ulnaris transfer for the correction of wrist deformity in radial longitudinal deficiency with preservation of ulnocarpal motion and epiphyseal growth. The surgical technique, indications, contraindications, and potential complications are described. Three cases with postoperative follow-ups at 36, 12, and 6 months, evaluating deformity and pre/postsurgical wrist mobility ranges, are reported. A correction was achieved in the forearm-hand angle of 71 to 88 degrees of the initial. The total range of movement, between 50 degrees and 80 degrees, was almost the same before and after the operation in the most anatomic position. In one patient, there was a residual deformity at the dorsoradial border, which showed no progression during the last 6 months of follow-up. For patients with radial longitudinal deficiency, functional outcomes with preserved mobility appear to hold greater significance. The technique described in this study enabled deformity correction while maintaining a wide range of motion. The preservation of the physis in a different orientation is an aspect that will need evaluation in long-term follow-up but offers potential treatment options in the future
due to the unknown of the secondary deformity, it is recommended that the long-term results should be awaited before adoption of this technique.