[For the purpose of introducing this memo, and not appearing presumptuous in presenting it, following is a summary of my orthopedic credentials: (1) advanced degrees in bioengineering/orthopedic biomaterials (2) former global head of R&D for orthopedic companies during industry career and (3) significant experience in hospital/ASC facilities and surgeon management company worlds. The point is we understand orthopedics, related technologies, facility-side and surgeon issues and concerns related to providing quality patient care. But we also know marketing. Sometimes the latter runs ahead of the former. Our premise is that we all share the responsibility to provide patients with products and technology that facilitate quality care, successful outcomes, and do so in a fiscally responsible manner.]
This is not intended as a patient specific, custom cutting block bashing paper, although it may appear as such to those currently supporting their use. Patient specific cutting blocks may turn out to be a clinically viable alternative that accomplishes the objectives noted above. But there are legitimate questions yet to be answered. I suggest the following points should be part of meaningful discussions on the subject. References include excerpts of an AAOS discussion between surgeons (pro and con), a JBJS article on long term clinical findings on TKR alignment and a published WSJ article on increased incidence of cancer with CT scans. We recognize MRI is typically suggested in the guide development process, but an additional x-ray is required, and there are instances where MRI is not appropriate and CT is used.
1. FDA: FDA expressed public concern over these blocks requiring more information to support their use clinically. Warning letters were sent to several of the Big Five orthopedic companies requiring them to stop producing and using these blocks until that information was provided. Since I initially wrote this, FDA has given 510(k) approval to several.
2. Information that may be construed as misleading: Your attention is directed to website information that some may perceive as too strong or misleading about what these products “may” do. The use of the word “may” in marketing information is a means of promotion, but also allows for disclaimers to help mitigate liability. Patients may not understand that. They tend to read only the first part and not the small print. It is left to surgeons to make sure the patient is informed.
3. Not a “Custom Knee”: Further, it was observed on surgeon and company blogs that some patients feel they are getting a “custom” knee replacement. That is misleading as these alignment guides are adapted to fit standard implants. In some, if not all, the computer program chooses the size for the surgeon based on company data. Thus companies with fewer sizes will default to the closest size available on both femoral and tibial sides. This is far from custom and may not consider other intra-operative sizing issues. The same set of cuts is made on the femur (anterior, distal, posterior and chamfer) and tibia because the same off the shelf implants are used. It should be noted that the same instruments may be used to make the cuts. As one would expect, Internet reports discuss early successes and failures using the guides.
4. No clinical history: In some cases, there isn’t any clinical history demonstrating how the cutting guides improve outcomes. In the U.S., since most of these guides just (or recently) gained approval, we have only short term information with mixed results. This is going to be a problem in the payor world as the battle rages over what is reimbursable and what is not; what produces quality clinical outcomes and what simply adds costs and no value.
5. Fit, form and function: Several of the patient specific cutting guides are pin locators only. The surgeon still has to fit TKR cutting blocks on the pins to make the cuts, as is done with navigation. To accomplish the intended purpose, the guides must fit snugly on the bones dictated by the scan to determine location. This does not always happen with the degree of accuracy intended. We have not seen what happens or how they are used when there are soft tissue anomalies, large osteophytes or image translation errors, all of which are part of TKR procedures. The question needs to be asked how the guides work when the surgeon has to re-cut due to some soft tissue contracture or other deformity. If the argument is they are alignment guides only, then that is how they should be marketed to surgeons and patients.
6. Materials: The guides are fabricated from “medical grade plastics.” High speed instruments, drilling and cutting through such blocks, raise concerns over the addition of foreign body particulate. I have been in many hundreds of TKRs in my career and the “chatter” associated with drills and blades is not insignificant. The fact that the guides are plastic has to do with process fabrication limitations, not necessarily what is the best material. For example, to help avoid this scenario with drill bits, some have inserted metal grommets for drill holes. Early versions had cutting slots directly in the plastic block — not good under any circumstances. Metal shims were added to help the problem. Thus most of the guides today serve as drill guides for locating pins and then standard metal cutting blocks are used to make the bone cuts.
7. Standard instrument set ‘on call’: A set of knee instrument trays must be up sterile, in the field or close by just in case. That is in case the block does not fit or intra-operative changes are made. Patella and other standard instrument trays are always required as one would expect.
8. Time: One proposed advantage is that these guides are said to decrease surgeon and case time, unlike navigation which typically increases time. That is surgeon specific as with any new procedure. Patient time and trouble are clearly increased by requirements for a scan and additional x-ray. It is safe to say for most of us as patients, we do not want to make added trips to an imaging center or hospital if they are not necessary. TKR patients have to wait several weeks to months to get surgery scheduled while custom guides are being fabricated. Because delivery dates on these guides fluctuate, surgery scheduling can be affected at the surgeon’s office and the facility.
9. COSTS: MRI (or CT), long x-ray, the cutting guide itself, patient out of pocket costs and time. These are significant costs that are justified in various ways by the orthopedic manufacturers who sell them. The cutting guides have been shown to cost $800 to $1600 each. The process is akin to what we used for many years called rapid prototyping. That is not new. It is an expensive, time consuming process. So the companies need to pass this along this cost to the facility if they can. The company may eat the cost in a pilot, but that is not sustainable. The patient factor costs can be very significant, including out of pocket expenses like high deductibles assuming their insurance will cover these costs. We suspect some will question the medical necessity of this until proven to add value, not cost, to the result.
In a healthcare economy like ours, the goals ought to be quality outcomes and cost reduction. ANOVA believes those goals are not mutually exclusive. Adding what may be construed as unnecessary costs to the system violates our basic operating premise. Ultimately, clinical follow-up with regard to improved patient outcomes and cost justification will need to be produced to validate ongoing and routine use.
10. Patient safety concerns: Increased exposure to radiation via additional x-ray and CT scan (if MRI is not possible). Patients today are much more cognizant of and concerned about all scans. MRI is not without its concerns.
I hope this summary is helpful and will serve as another layer of information as you evaluate products and technologies to determine what is best for your patients and fiscal management.
Sincerely,
Walter P. Spires, Jr.
Chief Executive Officer
ANOVA Orthopaedic Solutions
Office: 615-457-3311; email: walter.spires@anovaortho.com
Company website: www.anovaortho.com
References:
1. Lombardi AV, Vail, TP. Patient-specific instruments primary TKA: For. Part of symposium B, “Debates on contemporary issues in total knee replacement.” Presented at the 2011 Annual Meeting of the American Academy of Orthopaedic Surgeons. Feb. 15-19, 2011. San Diego. Drs Lombardi and Vail are paid consultants to Biomet and DePuy respectively.
2. “Effect of Postoperative Mechanical Axis Alignment on the Fifteen Year Survival of Modern Cemented Total Knee Replacements,” Paratte MD, Pagnano MD, Trousdale MD, Berry MD, (Mayo Clinic), Journal of Bone and Joint Surgery, 2010:92:2143-9.
3. Wall Street Journal (WSJ.com) article titled, “CT Scans Linked to Cancer,” December 15, 2009.
