Development of a Pneumatic Tensioning Device for Gap Measurement during Total Knee Arthroplasty

The goal of total knee arthroplasty (TKA) is to achieve a well-aligned tibiofemoral and patellofemoral joint sur-rounded by a well-balanced soft-tissue envelope.1-3) Soft tissue balancing in TKA should create a symmetric medial and lateral joint gap throughout the range of motion.4) Tight gaps may lead to limited motion, a less than satisfac-tory result, or adverse wear of the polyethylene compo-nent.5) Knee instability has been documented as a cause of pain and poor results after cruciate-retaining or posterior-Background: Despite the importance of soft tissue balancing during total knee arthroplasty (TKA), all estimating techniques are dependent on a surgeon’s manual distraction force or subjective feeling based on experience. We developed a new device for dynamic gap balancing, which can offer constant load to the gap between the femur and tibia, using pneumatic pressure during range of motion. Methods: To determine the amount of distraction force for the new device, 3 experienced surgeons ’ manual distraction force was measured using a conventional spreader. A new device called the consistent load pneumatic tensor was developed on the basi