A 60-year-old woman sustains a distal radius fracture treated with cast immobilization. At 8 weeks, X-ray shows no bridging callus. Which of the following definitions best applies to this situation?
- A Malunion
- B Delayed union ✓
- C Non-union
- D Fibrous union
Correct answer: B. Delayed union
Explanation
Delayed union is defined as failure of a fracture to unite within the expected time frame for that particular bone and fracture type, typically considered >3 months for most long bones, though contextual to fracture site. Non-union is defined after 6 months (or per FDA criteria, >9 months with no radiographic progression for 3 months) when healing has ceased without union. At 8 weeks for a distal radius fracture (expected union 6-8 weeks), delayed union is the correct classification. Malunion implies union in a faulty position; fibrous union is a subtype of non-union.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.