By Moby Parsons, MD

Up to 20% of patients who undergo a traditional knee replacement may be dissatisfied with the results of their surgery due to persistent pain in the joint.  This pain may result from instability, stiffness, inappropriate implant size or improper placement. Traditional implants come in a range of sizes that represent averages across the entire size spectrum. For some patients, however, these average sizes may be either too big or too small if a patient’s anatomy is somewhere in between. In such cases, surgeons have to make compromises  to best fit the implant to the patient and these compromises contribute to postoperative pain or poor function.

Recognizing this problem and the frequency of unsatisfactory outcomes after knee replacement, Conformis has developed and refined the technology of using 3D printing to fabricate patient-specific implants that are designed to exactly match an individual’s anatomy and replicate the form and function of the native knee. Using a conventional CT scan of the knee that includes  some images of the hip and ankle, computer software can calculate the shape and position of the implant that achieves these goals and restores the proper alignment of the leg when the arthritis has caused deformity. Along with creating the implant itself, the manufacturing process also produces the additional parts of the system that ensure the implant is perfectly placed during surgery. These are called cutting jigs, and like the implant, they are designed to exactly fit the patient’s bone during surgery to guide the surgeon in making accurate cuts. Thus, the whole system is customized for each patient!

While other new technologies such as computer navigation and robotic assistance have sought to improve a surgeon’s ability properly implant the knee prosthesis, these advancements still rely on conventional off-the-shelf knee implants. Therefore, while they may succeed in reducing errors in implant positioning, they still fall victim to the compromises that average sized implants must make to fit all patients. Because Conformis addresses both the accuracy of implant placement, as well as the accuracy of implant fit, it represents a true revolutionary step forward in knee replacement surgery that is likely to reduce the number of unsatisfied patients and improve functional outcomes. Based on these merits, we at Seacoast Orthopedics & Sports Medicine, are offering the Conformis knee for suitable candidates for knee replacement surgery.