Four Main Stages of Healing After Bone Fracture

3. Hard Callus Formation

(2 weeks-6-12 weeks) Cartilage begins to transform into woven bone. It takes longer for lower limbs than upper limbs. It's controlled by release of calcium and phosphorus minerals into the cartilage, forming a hard callus over the fracture site. The end of this is called "fracture union". Gentle weight bearing encourages this process, so removable cast walkers are suggested.

2. Soft Callus Formation

(4 days-3 weeks) Fibroblast cells start to form cartilage to fill the gap-but it's fragile, fracture must be kept immobile (sling or cast)- new blood vessels start to form

1. Inflammation

(3-5 days) There's bleeding in the tissue and the trauma doctor must return bone fragments to place to stem blood flow. A mesh of blood clots between the fragments.

4. Remodeling

(6-12 weeks+) The body lays more hard callus than necessary during bone healing, enlarging the bone. After uniting, bone remodeling occurs and the bone shape becomes normal. The osteoclasts remove unneeded bone and osteoblasts lay bone where needed. Full weight-bearing exercise increases bone strength. Loosely organized woven bone gets replaces by high organized Lamellar bone