Although some surgeons see patient-specific orthopedic implants as a step forward in joint care, others say they're a marketing ploy with flaws.
Three surgeons shared with Becker's Spine Review their predictions for the technology over the next 10 years.
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Question: How will patient-specific orthopedic implants evolve in the next decade?
Andrew Bush, MD. Central Carolina Orthopaedic Associates (Sanford, N.C.): Patient specific implants for the general population is nothing but a marketing ploy. Individualized implants made for patients undergoing limb-salvage type of surgeries is an established process and has an important place in patient care. However, for the general population there are several reasons why this concept is flawed:
1. There's the sheer number of patients requiring implants.
2. How would the implant designer know what is the "normal" joint design for a patient? The reason why a patient has been indicated for an implant is because the joint has become affected by arthritis, and is no longer normal. Are we going to be modeling our designer joints from an abnormal joint and "guessing" what it would have looked like when it was normal?
3. As long as the methods of fixation haven’t significantly changed in the past 30 years (cemented or press-fit) then the whole established theory of implantation will remain applicable including the theory of soft-tissue balancing and maintaining the long axis of the lower extremity in either neutral or slight valgus in knee replacement, maintaining appropriate offset in hip replacement, etc. These processes are based on soft tissue tensions and are altered as joints age and deteriorate, and although are addressed and "corrected" during the surgical process, they are not returned to "normal" so a custom implant would no longer really be customized due to the changes made during surgery.
Having performed several hundred robotic assisted joint replacement surgeries, I am of the opinion that robotic assisted surgery is the future of joint replacement surgery. A patient will be best served at our current level of technological development by having a well-designed generic implant that is made from the appropriate materials and is appropriately sized during the robotic procedure, implanted with automated precision that is based on the dynamic force measurements intra-operatively obtained by the computer driven robotic system. It has been shown over the years that a well placed implant will have an expected survivability of 15 to 20 years — any improvement in that expected timeframe would be based on better material development, better fixation method and /or a better method of implant placement.
Ammar Saymeh, DPM. NJ Spine and Wellness (Freehold): The technology behind patient-specific surgical implants will continue to adapt and evolve over the next decade. As we focus our attention to improving patient outcomes, it is without a doubt amongst the most vital aspects of biomedical engineering research in our time. These implants continue to be improved year after year. The goal for both patient and surgeon alike are less revisions and overall increased longevity of the implant. When we hone in on the total ankle arthroplasty, for example, we find a dramatic increase in usage and success rates as the technology behind the implant continues to improve. In addition to an overall improvement in the development of patient specific implants, robotics and 3D-printed prosthesis will play a large role in improving patient outcomes. These patient specific implants will improve the biomechanics of the patient post-operatively. Patients will be able to have a much more active lifestyle and will not be inhibited by the orthopedic implant.
Cory Calendine, MD. Bone and Joint Institute of Tennessee (Franklin): Orthopedic implants will continue to evolve as we develop better tools — more precise, more versatile — to facilitate bony preparation. Gone are the days when we are limited only to a flat saw, a hammer and alignment guides with ankle clamps. However, I am not convinced that patient-specific implants are the final frontier. Patient-specific surgery is to boldly go where no man has gone before.
Speaking specifically of hip and knee replacement, every surgery must be customized and unique to that single patient. The implant is one part of this equation, but a patient's soft tissue is the other. To place a custom implant without accommodating the patient's soft tissue is to err. The challenge is: How do we reveal the patient's soft tissue needs prior to surgery? Or do we develop a way to fabricate a custom implant onsite, during surgery?