Even though Total Knee Replacement is a relatively successful operation, still 15% of patients remain unsatisfied with the results and 5% need revision surgery within 10 years (Cho, 2014; Noble et al, 2006). One of the possible explanations is suboptimal balancing of the knee during surgery (Unitt et al, 2008). BIOMET, one of the worlds leading orthopaedic manufacturers presented me and 5 other Integrated Product Design students with the following design goal:
“Design a product that can measure the balance in the knee during a Total Knee Replacement”
Where existing knee balancers need to be placed inside the knee and are limited to measuring at specific points during the operation, Knee Balance is placed externally onto the ankle and upper leg and can measure throughout the entire operation. The combination of force sensors, 9DOF sensors, an inventive casing and intuitive interface design gives the orthopaedic surgeon the opportunity to measure balance and adjust his actions at every moment during surgery, preventing unnecessary soft tissue loss and possibly improve clinical outcome of Total Knee Replacements.
The external placement furthermore provides unique new opportunities for diagnostic, revalidation and research purposes as Knee Balance can also be used before and after surgery, and outside the operation room.
We developed a very innovative product and worked out all details like the embodiment, sustainability, service system, software and interface.
References: Noble PC, Conditt MA, Cook KF, Mathis KB. The John Insall Award: Patient expectations affect satisfaction with total knee arthroplasty. Clin Orthop Relat Res 2006;452:35–43. Unitt et al, 2008 - Short-term outcome in total knee replacement after soft-tissue release and balancing - British Editorial Society of Bone and Joint Surgery – 7