Fracture healing
How a broken bone heals through a haematoma, inflammation, a soft cartilage callus and a hard bony callus that is remodelled into normal bone, and why movement, poor blood supply, infection and smoking can make healing fail.
By the end, you can
- Describe the structure, blood supply and periosteum of a long bone.
- Describe the stages of secondary fracture healing and their approximate timing.
- Explain how the soft callus becomes bone by endochondral ossification.
- Distinguish secondary (callus) healing from primary (direct) healing after rigid fixation.
- Explain the causes and consequences of delayed union, non-union and malunion.
- Recognise the appearances of a healing fracture, the Salter–Harris and Garden classifications and the tests of union, and explain how reduction, fixation, grafting and medicines act on healing.
What it is
Fracture healing is the process by which bone repairs a break and regains its original structure and strength, without leaving a scar. Most fractures heal by secondary healing, through a callus; fractures fixed rigidly with the ends compressed together can heal by primary healing, directly across the gap.
2 types to tell apart
- Secondary (indirect) healing
- With some movement at the fracture, as in a cast: haematoma, inflammation, soft callus, hard callus, remodelling.
- Primary (direct) healing
- With rigid fixation and close contact: osteons cross the fracture directly, without a visible callus.
US spelling: fibres → fibers.
Normal function
Bone and its blood supply
The shaft of a long bone is compact bone, built from cylindrical around central canals that carry . Osteocytes live in tiny spaces and communicate through canaliculi, sensing load.
The outer surface is covered by : a tough fibrous outer layer and an inner layer rich in osteoprogenitor cells that can become bone- or cartilage-forming cells. It is attached by and carries vessels into the bone.
Blood reaches bone from a nutrient artery into the marrow, from the periosteum and from vessels at the ends. A good blood supply and living periosteum are the two things a fracture most needs to heal.
Underlying change · Step 1 of 4
Haematoma and inflammation
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
A soft callus bridges the gap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
Hard callus and remodelling
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
When healing is delayed or fails
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .