A Handheld Device for Measurement of Tension: An Aide to Surgeons for Soft Tissue Balance During Orthopedic Surgeries

In a number of orthopaedic surgeries, balancing the tensile forces in the soft tissues surrounding bone is important for good restoration of overall limb function in the patient and a long lasting implant. This paper presents an analytical formulation for a handheld device which can be used to measure tension in the soft tissues surrounding bone. The handheld device can be pushed against a tense segment of any soft tissue to measure the site specific axial tension in the tissue. The device uses an array of three force (or displacement) sensors and estimates the tension in the string based upon an analytical formula that utilizes these three readings. Two different realizations of the device and their experimental results are presented which confirm the theoretical formulation. The developed handheld device can be useful in total knee replacement, ACL repair, shoulder stabilization, patella dislocation, tendon repair, total hip replacement and a number of other orthopaedic surgical procedures.