What are the acceptable radiographic parameters for closed reduction of a closed humeral shaft fracture in a 10‑year‑old child?

Acceptable Radiographic Parameters for Closed Reduction of Humeral Shaft Fracture in a 10-Year-Old

For a 10-year-old child with a closed humeral shaft fracture treated with closed reduction, accept alignment if Baumann's angle is within 4 degrees of the contralateral normal side on intraoperative anteroposterior radiographs.

Critical Radiographic Measurement

• Baumann's angle must be within 4 degrees of the normal contralateral side to prevent cubitus varus deformity and ensure acceptable alignment 1, 2.
• This measurement should be obtained intraoperatively by comparing anteroposterior radiographs of both distal humeri after internal fixation 1, 2.
• If the angles differ by more than 4 degrees, repeat the closed reduction and percutaneous pinning until this criterion is met before leaving the operating room 2.

Evidence Supporting This Standard

• A prospective study of 71 patients with displaced supracondylar fractures demonstrated that strict adherence to the 4-degree Baumann's angle criterion resulted in satisfactory outcomes in 70 of 71 patients (98.6%), with zero cases of cubitus varus deformity at average 2.5-year follow-up 1.
• A second prospective study of 20 children using this same 4-degree criterion achieved excellent or good results in all patients with no cubitus varus deformities at average 17.2-month follow-up 2.

Treatment Algorithm Based on Radiographic Assessment

For Displaced Fractures (Gartland Type II and III):

• Perform closed reduction with percutaneous pin fixation as the primary treatment 3, 4.
• Obtain intraoperative AP radiographs comparing both sides 1, 2.
• Accept reduction only if Baumann's angle is ≤4 degrees difference from normal side 1, 2.
• If criteria not met, repeat reduction and pinning 2.

For Nondisplaced or Subtle Fractures (Gartland Type I):

• Immobilize with posterior splint rather than collar-and-cuff 5.
• Maintain immobilization for approximately 3-4 weeks 5.

Critical Pitfalls to Avoid

• Do not accept inadequate reduction based on subjective assessment alone—always measure Baumann's angle bilaterally 1, 2.
• Do not leave the operating room until the 4-degree criterion is met, as post-operative correction is not possible 2.
• Assess neurovascular status carefully throughout treatment, as vascular compromise can lead to long-term loss of nerve and muscle function 5, 4.
• If closed reduction cannot achieve acceptable alignment despite proper technique, consider that soft-tissue interposition (periosteum, biceps tendon, deltoid muscle) may be preventing reduction and open reduction may be necessary 4, 6.

Additional Considerations for This Age Group

• A 10-year-old has significant but not unlimited remodeling potential, making anatomic reduction more important than in younger children 6.
• The American Academy of Orthopaedic Surgeons acknowledges that criteria for accepting adequate closed reduction require further research, but the 4-degree Baumann's angle criterion represents the best available evidence 7.
• Open reduction is associated with greater elbow stiffness compared to closed reduction with pinning, reinforcing the importance of achieving adequate closed reduction when possible 4.