Non-Union & Mal-Union

A non-union is a fracture that has failed to heal — meaning that well past the time the bone should have knitted back together, the X-ray still shows a gap. Non-unions come in three flavors: hypertrophic (the bone is biologically active but the fracture wasn't held still enough), atrophic (the biology itself is failing — the bone isn't trying to heal), or infected. A mal-union is different: the bone healed, but in the wrong position — shortened, angled, or rotated enough to cause pain, an abnormal gait, or accelerated joint wear over time.

• Persistent fracture-site pain — ongoing pain at the original break well beyond the expected healing window, usually several months
• Abnormal motion at the fracture — the bone moves where it shouldn't (non-union), sometimes with a grinding or shifting sensation
• Visible deformity — the limb looks shortened, angled, or twisted compared to the other side (mal-union)
• Compensatory problems — limping, altered gait, or pain in the joints above or below the healed-but-crooked bone

Sequential X-rays over time tell the story — healing should show progressive bridging bone forming across the fracture line. A CT scan is the most sensitive test for confirming non-union — it clearly shows whether bone has bridged the gap. Blood work checks for infection and for metabolic problems that could be slowing healing (vitamin D deficiency, thyroid issues, low calcium). A nuclear medicine bone scan can show whether the bone is still biologically active at the fracture site.

Most established non-unions — and any mal-union that's causing meaningful pain or functional problems — need surgery. The procedure typically combines two things: replacing or revising the fixation hardware to provide better stability, and adding bone graft to provide fresh biology at the fracture site. For mal-unions, an osteotomy (a controlled surgical re-break) is sometimes done first to put the bone back into proper alignment.

External patient-education references and related OSI pages for additional background:

• Britannica — Bone disease (fractures)
• Britannica — Human skeleton
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language