1. Bone Repair Challenge ~Biomedical Engineering~
[ Challenge is stated on last slide. ] 1

2. External Fixation
Temporary fixtures used to stabilize bone and soft tissues at a distance from the injury.
They are used in
severely comminuted
open fractures
to lengthen bone..

3. External Fixation
External fixation may be used when there is severe damage to the tissues.

4. External Fixation
External fixation allow the surgeon to adjust tension in the device as healing progresses.

5. Internal Fixation
Temporary or permanent fixtures directly attached to the bone under the skin for alignment and support.
screws
wires
grafting
pins
rods
nails

6. Internal Fixation
To determine the best repair technique, the break type and location are considered
During surgery, an incision is made over the fractured bone. The bone is placed in proper position and screws, pins or plates are attached to or in the bone temporarily or permanently. Any disrupted blood vessels are tied off or burned (cauterized). If a quantity of bone has been lost because of the fracture, especially if there is a gap between the broken bone ends, the surgeon may decide that a bone graft is essential to avoid delayed healing. If a bone graft is not necessary, the fracture can be repaired by the following methods:
a) one or more screws inserted across the break to hold it
b) a steel plate held by screws drilled into the bone
c) a long fluted metal pin with holes in it, is driven down the shaft of the bone from one end, with screws then passed through the bone and through a hole in the pin
In some cases, after this stabilization, the microsurgical repair of blood vessels and nerves is necessary. The skin incision is then closed.
Source:
Image source: US National Library of Health, National Institutes of Health, Medline Plus, 6

7. Example: Rods, Plates and Screws
Rods are used for alignment and support of long and large bones
Plates hold together loose pieces of bone and support smaller bones
Screws hold plates and rods in place
An internal fixation device may be used to keep fractured bones stabilized and in alignment.
The device is inserted surgically to ensure the bones remain in an optimal position during and after the healing process.
Source:
Image source: US National Library of Medicine, National Institutes of Health, Medline Plus, 7

8. Example: Rods, Screws and Pins
Pins are similar to screws and usually affix a detached piece of bone
Broken right ankle with surgical fixation: A. Pre-operative view of the right lower leg revealing fractures to the distal tibia and fibula
B. Incision into the leg and ankle
C. Placement of screws and an intramedullary rod into the tibia
D. Post-operative view of the fracture hardware in place
[intramedullary rod = a medical device inserted into the bone marrow canal in the center of the long bones, such as femur or tibia]
Source:
pin
Image source: Medical illustration copyright © 2009 Nucleus Medical Art. All rights reserved Used with permission. 8

9. Example Spiral fracture-torsion break
Tibia and fibula broken while skiing and repaired with a rod and pins.
Spiral fracture-torsion break
These are x-rays after surgery, showing along titanium "nail" along the length of the tibia, with pins at either end.
The little dashes are the metal staples used to stitch up the incisions.
Image source: Art’s Spiral Fracture Pix, University of Arizona., Used with permission. 9

10. More Plates and Screws
X-ray example of shattered dog femur that was repaired with a plate and seven screws
A two-year-old dog with a comminuted femoral fracture. [comminuted = a fracture of many small fragments]
The fracture was treated with a bone graft and fixed with a plate and seven screws.
Healing is seen at eight months following surgery.
Image source: David M. Nunamker, University of Pennsylvania School of Veterinary Medicine. Used with permission. 11

11. Bone Grafting Bone grafts may be
harvested from the patient’s own body,
obtained from a bone bank,
made of synthetic material
A nonunion of six months' duration with an intramedullary pin for fixation. On physical examination 90¡ of rotation was felt, so an on-edge half-thickness hip bone graft was applied
x-rays four weeks later
x-rays eight weeks after surgery
bone is repaired (union) 13

12. graft area
Image source: David M. Nunamker, University of Pennsylvania School of Veterinary Medicine. Used with permission.