Question

14 YO Girl Admitted with a Broken Leg History: Nicole Michaelson, a 14-year-old girl, was skiing when she fell and broke her left leg. As she fell, her left leg got caught under the body of another skier who ran into her. An X-ray revealed that the fracture was a compound, tibial-fibular fracture just below the knee. The X-ray also revealed a torn meniscal cartilage in the knee above the fracture. The girl remained in the hospital for 14 days because of an infection of the leg in the area of skin breakage. Her immobilized leg was casted after the infection subsided. She remained in a full leg. length cast for 3 months, after which the upper portion of the cast was removed and she was allowed to start bearing weight on the leg. The bones ultimately healed, but the girl continued to have left knee swelling ("water on the knee") and pain made worse by walking. Arthroscopic examination of the knee revealed a meniscus that was still torn 6 months after her injury. 1. Why was her injury more likely to become infected than a routine fracture of the leg? 2. How does weight-bearing influence the bone repair process you described above? (i.e. what effect does weight-bearing have on the orientation of the Haversian systems?) 3. Why did Nicole's bones heal much more quickly than her cartilage?

Answer 1

1. The injury happened to Nicole is most likely infected than other routine fractures.This is because of the nature of the fracture occurred. The fracture took place is a compound fracture where the bone penetrates surrounding tissues and skin.This is almost a open fracture.Compound fractures are more dangerous than other fractures.These usually takes 3 months to heal and the open compound fractures take more time of to heal extending further 4 to 6 weeks.

2. Weight bearing during fractures actually improves the strength of the bones.Full weight bearing activities promotes the formation of hard callus which helps the fracture to remain and heal.Haversian system or canals is other wise called as late on which contains osteocytes, nerves, lymph fluid, arteries and veins etc.These are actually found in the matrix structure of the bone.Because of the exercises these microscopic structures of the bones changes and gets adapted to the normal process thus repairing or healing the fractures.

3. This is because bones contain many blood vessels that supply blood and oxygen which promotes better healing.Where as cartilage will have only a few in number and thus there will be a poor blood supply.