Post-Traumatic Radioulnar Synostosis 17 Years After Forearm Fracture: A Case Report and Literature Review

 Corresponding author: F. Rifki Copyright © 2025 Author(s) retain the copyright of this article. This article is published under the terms of the Creative Commons Attribution License 4.0. Post-Traumatic Radioulnar Synostosis 17 Years After Forearm Fracture: A Case Report and Literature Review F. Rifki 1, *, M. Akhouayri 1, N. Elghoul 1, H. Salahi 1 and A. Azzouzi 2 1 Department of Orthopaedics and Traumatology, Avicenne Military Hospital, Marrakech. 2 Department of Anaesthesia, Avicenne Military Hospital, Marrakech. World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 Publication history: Received on 05 October 2025; revised on 10 November 2025; accepted on 13 November 2025 Article DOI: https://doi.org/10.30574/wjarr.2025.28.2.3831 Abstract Post-traumatic radioulnar synostosis (PRUS) is a rare but debilitating complication of forearm fractures, characterized by osseous fusion between the radius and ulna. We report a case of PRUS that developed 17 years after surgical fixation of a forearm fracture. Surgical excision of the synostosis led to excellent functional recovery. This case highlights the long-term risk of heterotopic ossification after forearm trauma and underscores the importance of meticulous surgical technique and early mobilization. Keywords: Post-traumatic radioulnar synostosis; Heterotopic ossification; Forearm fractures; Surgical excision; Radioulnar fusion; Forearm trauma complications 1. Introduction Post-traumatic radioulnar synostosis (PRUS) is an uncommon but serious complication following fractures or surgical interventions of the forearm. It leads to an osseous bridge between the radius and ulna, resulting in loss of pronationsupination and significant functional limitation. Incidence rates range from 1% to 6%, and risk factors include highenergy trauma, extensive soft-tissue damage, delayed fixation, and reoperation. This report describes a case of proximal PRUS in a patient who sustained a forearm fracture 17 years earlier, had hardware removal one year later, and subsequently developed a mature bony synostosis. Surgical excision provided a good functional outcome with restored range of motion. 2. Case Report A 37-year-old male presented with progressive stiffness of the left forearm. Seventeen years prior, he had sustained a diaphyseal fracture of the radius and ulna, treated with open reduction and internal fixation. The osteosynthesis material was removed one year after fracture consolidation. The patient gradually developed loss of forearm rotation without pain. Clinical examination revealed complete loss of pronation and supination but preserved flexion and extension at the elbow. Neurovascular examination was normal. Plain radiographs and computed tomography (CT) scans showed a mature osseous bridge between the proximal radius and ulna consistent with a type III post-traumatic synostosis (according to the Vince and Miller classification). Surgical excision was performed under general anesthesia using a posterior approach. The bony bridge was completely resected, taking care to preserve the posterior interosseous nerve. Early postoperative mobilization was initiated, and physiotherapy began on the second postoperative day. World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 1131 At follow-up, the patient recovered satisfactory pronation and supination, with no recurrence of synostosis or instability. Histological examination of the resected specimen showed mature lamellar bone without atypia. 3. Discussion Radioulnar synostosis may occur after high-energy fractures, multiple surgeries, or excessive periosteal stripping. Vince and Miller classified post-traumatic synostosis into distal (type I), diaphyseal (type II), and proximal (type III) types. Our case corresponds to a type III lesion. Surgical resection is the standard treatment, preferably delayed until ossification matures (6–12 months post-injury) to reduce recurrence. Giannicola et al. (J Shoulder Elbow Surg, 2019) reported that surgical excision of proximal PRUS yields favorable outcomes when performed with meticulous technique and careful protection of neurovascular structures. Interposition of soft tissue (fascia, fat, or anconeus muscle) may further prevent recurrence. Early postoperative rehabilitation is essential to maintain range of motion. Recurrence remains a concern, particularly when resection is incomplete or performed prematurely. The use of nonsteroidal anti-inflammatory drugs and radiation therapy as prophylaxis remains controversial. Figure 1 Preoperative radiograph showing proximal radioulnar synostosis World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 1132 Figure 2 CT scan confirming osseous bridge between radius and ulna World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 1133 Figure 3 Intraoperative view showing exposure of the synostosis. World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 1134 Figure 4 Postoperative radiograph demonstrating complete excision of the synostosis Figure 5 Full range of motion after surgery World Journal of Advanced Research and Reviews, 2025, 28(02), 1130-1135 1135 4. Conclusion Post-traumatic radioulnar synostosis is a rare but disabling condition. Complete excision of the synostosis, combined with early rehabilitation, can provide excellent functional outcomes. Long-term follow-up is necessary to detect potential recurrence. Compliance with ethical standards Disclosure of conflict of interest No conflict of interest Statement of ethical approval Ethical approval was obtained. Statement of informed consent Informed consent was obtained from all individual participants included in the study. References [1] Giannicola G, Spinello P, Villani C, Cinotti G. Post-traumatic proximal radioulnar synostosis: results of surgical treatment and review of the literature. J Shoulder Elbow Surg. 2019;28(12):1–11. [2] Vince KG, Miller JE. Cross-union complicating fracture of the forearm. Part I: Adults. J Bone Joint Surg Am. 1987;69(5):640–53. [3] Jupiter JB, Ring D. Operative treatment of post-traumatic proximal radioulnar synostosis. J Bone Joint Surg Am. 1998;80(2):248–57.