Forearm malunion resulting from traumatic injuries can lead to reduced pronosupination and instability of the distal radioulnar joint (DRUJ). While children benefit from natural bone remodeling, surgical intervention is more frequently required in adults. When surgical treatment is necessary, corrective osteotomies aim to restore functionality and alleviate pain. However, in cases of complex multiplanar deformities, surgical planning can be technically challenging. Moreover, there is a lack of literature addressing the management of DRUJ instability in these cases.

We present the case of a 52-year-old patient with severe malunions of both forearm bones, characterized by a 10-degree pronation and 5-degree supination, along with chronic DRUJ instability. The patient reported difficulty with daily activities due to limited forearm rotation, pain, and persistent joint instability. The patient underwent corrective surgery, utilizing three-dimensional (3D) planning and patient-specific instruments (PSI) to perform precise osteotomies on both the radius and ulnar shafts. In addition, DRUJ instability was managed conservatively using a 6-week treatment protocol involving bracing and physical therapy, which successfully stabilized the joint. Postoperative assessments at 13 months showed significant improvements, including the absence of pain, increased pronosupination range, and successful bone union, as confirmed by radiographic evaluation.

The role of 3D planning and PSI in orthopaedic surgery has been well-documented, particularly in the management of forearm malunions in pediatric patients and complex malunions of distal radius fractures in adults. Evidence suggests that these technologies improve both surgical and radiographic precision, reduce complications, and enhance long-term outcomes.

This case contributes to the existing body of literature by demonstrating how these tools can be successfully applied to complex both forearm bones malunions with concurrent DRUJ instability in an adult patient.

This case report was conducted in accordance with ethical standards.

Written informed consent for publication of the case details and associated images was obtained from the patient. The patient's identity has been anonymized to maintain confidentiality.

Received: 22 March 2025

Accepted: 16 June 2025

Article published online:
02 July 2025

© 2025. Thieme. All rights reserved.

Thieme Medical Publishers, Inc.
333 Seventh Avenue, 18th Floor, New York, NY 10001, USA