A 28-year-old man sustains a closed tibial shaft fracture managed with an intramedullary nail. At 6 months post-surgery, radiograph shows bridging callus on 3 cortices but no remodelling. He has mild pain on full weight-bearing. This is best described as:

• A Established non-union
• B Delayed union ✓
• C Normal progress — tibial IMN callus routinely appears at 6 months
• D Atrophic non-union

Explanation

Delayed union is defined as a fracture that has not united within the expected timeframe for that particular bone and injury but still shows evidence of ongoing repair (callus formation, absence of sclerosis). For tibial shaft fractures, union is expected by 3–4 months for simple patterns. At 6 months with bridging callus on only 3 cortices (not 4) and residual pain, this represents delayed union — not yet non-union (which requires failure to progress for 6–9 months with sclerotic, rounded fragment ends). Hypertrophic non-union would show abundant, exuberant callus with no bridging.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.