What are the stages of bone healing?
When you break a bone where does bleeding normally come from?
Periosteum (Haversian canals) and bone marrow
How does the body react immediately after a bone break?
The sirens go off (mast cells, platelets and basophils). Then their chemical mediators increase vasodilation and cause edema. They also attract phagocytes for debris removal. Neutrophils attract macrophages which release mediators for the PROLIFERATIVE phase.
What cells enter the scene during the proliferative phase of bone healing?
Osteoclasts come in at the end of the inflammatory phase and osteoblasts follow them, building up bone.
A 17 year old basketball player comes to see you after taking a hard fall during a basketball game. You find that he has a hairline fracture in his patella and a sprained ankle. He says he wants to get back to playing as soon as he can. Do you prescribe NSAIDs? If he broke a different bone would you change your decision?
No. The break will take longer to heal if you prescribe NSAIDs because they inhibit COX-1 which decreases the amount of prostaglandins produced and thus decreases proliferative mediators released by macrophages. If he broke a bone with a good blood supply, such as the clavicle, you could prescribe NSAIDs.
Why did this fracture take two weeks to show up?
Osteoclasts chew up the dead bone (died because its blood supply is damaged) after the inflammatory response, causing initial widening of the fracture which makes it more visible. The scaphoid has a poor blood supply so it takes a long time for this to happen.
Why is the fracture fuzzy in this image?
Calcium and phosphate are starting to ossify the osteoid being laid down by the osteoblasts in the proliferative phase.
Why is it a good thing that the bony callus formed on the mid clavicle after a fracture gets remodeled and shaved back down?
The bony callus is stronger than the surrounding bone, however, you don't want a proximal or distal clavicle fracture. Bones have weaker regions for a reason and keeping a stronger callus in an originally weaker region can put other regions at greater risk for fractures.
What is the main difference in bone and tendon repair?
The tendon has a much shorter time period of inflammation
Why are the terms tendinitis and fasciitis wrong?
Tendons and fascia do not have blood supply and cannot become inflamed themselves. Tendinitis is actually just degeneration of the fibers.
What type of physical therapy is good for tendon repair?
That involving eccentric contraction. Eccentric contraction is the most strenuous on your muscles, causing the greatest amount of inflammation, allowing inflammatory mediators to get to injured tendons and initiate repair.
What is prolotherapy?
Injection of platelet rich plasma to the site of tendinitis to increase the inflammatory response and mediate healing of the tendon
Do ligaments or tendons tend to heal better? Why?
Ligaments, they have bone on each side of it which has a good blood supply.