Management of Acute Transverse Nondisplaced Distal Radial and Ulnar Diaphysis Fracture with Apex Volar Angulation in a 6-Year-Old
For this 6-year-old with a nondisplaced both-bone forearm fracture with apex volar angulation, immobilize in a long-arm cast for 3 weeks, followed by radiographic reassessment and transition to a short-arm cast or removable splint for an additional 2-3 weeks based on healing progress. 1
Initial Immobilization Strategy
Use a long-arm cast (above-elbow) initially to control rotation and prevent displacement, as both-bone forearm fractures in children require more rigid immobilization than isolated distal radius fractures 1
The total immobilization period should be 3-5 weeks for nondisplaced pediatric forearm fractures, which is shorter than the traditional 6-week protocol used in adults 2, 3
Apex volar angulation is particularly concerning in this fracture pattern because it can lead to volar dislocation of the distal ulna with forearm supination if malunion occurs, making accurate reduction and maintenance of alignment critical 4
Radiographic Monitoring Protocol
Obtain radiographs at 1-2 weeks post-immobilization to confirm maintenance of alignment, as this is when early displacement typically occurs if it's going to happen 5
The AAOS guidelines indicate that reduced frequency of radiographic follow-up does not adversely affect outcomes, but given the apex volar angulation pattern and its potential complications, at least one early follow-up radiograph is prudent 5
Obtain final radiographs at 3 weeks to assess healing before transitioning to less rigid immobilization 6, 2
Acceptable Alignment Parameters
Monitor for any increase in apex volar angulation, as children aged 6 years have substantial remodeling potential but apex volar deformities in the distal radial shaft are prone to causing distal radioulnar joint instability 4
If post-reduction imaging shows radial shortening >3 mm, dorsal tilt >10°, or intra-articular displacement, surgical intervention should be considered per AAOS guidelines, though these criteria were developed primarily for adults 5, 6
In this 6-year-old, accept up to 15° of angulation in the distal radius given the remodeling potential, but be more conservative with apex volar patterns due to the risk of distal ulnar instability 1, 4
Critical Management Pitfalls
Never use a removable splint for this fracture pattern - removable splints are only appropriate for stable, minimally displaced buckle fractures, not both-bone diaphyseal fractures with angulation 7, 8
Apex volar malunion specifically predisposes to volar dislocation of the distal ulna during supination in adolescence, making initial reduction and maintenance of alignment particularly important 4
Initiate active finger motion exercises immediately to prevent stiffness, which does not adversely affect adequately stabilized fractures 7, 8
Transition to Less Rigid Immobilization
After 3 weeks, if radiographs show adequate callus formation and maintained alignment, transition to a short-arm cast or removable splint for an additional 2-3 weeks 1, 2
Total immobilization duration of 5 weeks is typically sufficient for nondisplaced pediatric forearm fractures, with shorter durations (3 weeks) showing equivalent outcomes in some studies 2, 3
Long-Term Monitoring Considerations
Follow this patient into adolescence if any residual apex volar angulation persists, as the two reported cases of volar ulnar dislocation from apex volar radial malunion both occurred in boys who sustained their initial fractures at ages 6 and 8 years 4
If progressive apex volar deformity develops or distal radioulnar joint instability emerges, corrective radial osteotomy at the malunion site is the definitive treatment 4