A Systematic Review of Functional Outcomes Following Surgical and Conservative Management of Congenital Radioulnar Synostosis

Congenital radioulnar synostosis (CRUS) is a rare upper limb malformation causing fixed forearm malposition. Management remains controversial, with no consensus on indications for surgery or the optimal operative technique. This systematic review evaluated reported outcomes of surgical and conservative management of CRUS. A systematic review was conducted in accordance with PRISMA and registered with PROSPERO (CRD42019148014). MEDLINE, Embase, Journals@Ovid, Cochrane, CINAHL, BMJ Case Reports, and Google Scholar were searched to 20 February 2026. Studies of any design reporting management of CRUS were included. Data were extracted on laterality, treatment type, forearm position, functional outcomes, complications, and follow-up. Risk of bias was assessed using Joanna Briggs Institute (JBI) critical appraisal tools. A total of 55 studies were included, comprising 662 patients and 856 forearms; 195 patients (29.5%) had bilateral involvement. Surgical management was reported in 552 patients and conservative management in 110. There was no consistent indication for surgery: some studies used functional limitation while others used fixed pronation thresholds. Surgically treated patients had greater deformity and were more likely to have bilateral disease than those managed non-operatively. Derotational procedures consistently improved resting forearm position, achieving a mean postoperative position of 1° pronation, and were associated with improved functional outcomes. In contrast, simple synostosis resection generally failed to maintain motion because of recurrence, while more complex interposition procedures showed more promising but less reproducible results. Complications were reported in 61 surgically managed patients (11.1%), including nerve palsy, recurrence, loss of alignment, vascular compromise, non-union/delayed union, wound infection, and compartment syndrome. Evidence for CRUS management is limited by low quality, heterogeneous studies. Operative treatment may improve function but carries a meaningful risk of complications. Treatment should therefore be individualised, with decisions based on functional limitation, compensatory shoulder and elbow motion, deformity severity, and bilateral involvement.