In vivo loads in the medial compartment of the rabbit knee.

Background: The compressive loads produced in the medial compartment of a rabbit knee during hopping are unknown, and necessary for the development of an animal model to study unicompartmental osteoarthritis.

Methods: In an effort to obtain such data, a surgical procedure was developed to insert a pressure sensor into the medial tibial compartment of a New Zealand white rabbit knee joint, and an inactive sensor of the same thickness into the lateral tibial compartment. After the rabbits recovered from anesthesia, contact pressure was measured as the rabbits hopped.

Findings: The average peak pressure in the medial compartment was 60 N/cm2 (SD 16), a value that corresponds to 39% of the animals' body weight (range: 21-61%, SD 11%).

Interpretation: This is the first report of measured in vivo pressures associated with the load transmitted through the medial compartment of the skeletally mature New Zealand White rabbit, a model frequently used to study the progression of osteoarthritis.