Isometer for determining isometric positioning of ligament transparent - has supporting foot applied to one bone of joint, traction element, spring, holder and indicator

摘要

An isometer (1) for determining the isometric positioning of a ligament transplant has a support foot (18) applied to one of two bones of a joint, a spring acting between a holder joined to the foot and a traction element passing through a bore in one bone and an indicator (10). The indicator shows the elastic spring deformation and is attached to the traction element either directly or via a transmission. The transmission ratio is not proportional to the displacement of the traction element over the displacement distance and the distance of the supporting foot from the holder is adjustable. ADVANTAGE - Enables accurate measurement of how strongly ligament transplant applied to joint is extended when joint is bent.