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Surgeon education crucial to success of minimally invasive knee arthroplasty
Multinational study showed 95% of patients with uni-knee arthroplasty had high satisfaction rates.
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Many patients set to undergo knee arthroplasty surgery are requesting procedures that are less invasive, leave a smaller scar and allow quicker recovery. However, orthopedic surgeons are unsure what data exist that support such procedures, and for whom they are indicated.
The Knee Committee of the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) recently held a symposium to present scientific information that supports “mini-knee” procedures and meet such demands, but also yield outcomes comparable to total knee arthroplasty. Beyond addressing minimally invasive surgery (MIS), the symposium focused on “reduced-incision” total knee arthroplasty (TKA), according to Christopher E. Ackroyd, FRCS.
He said knee surgeons today should be thinking of these procedures that way — as TKAs done with a reduced incision size — rather than as “mini-knee” arthroplasty surgery.
Respect to indications
“More surgeons in Europe than in the United States choose unicompartmental TKA,” said Philippe Neyret, MD, who chairs the ISAKOS Knee Committee and moderated the symposium held during the 2007 congress.
Neyret told Orthopedics Today, “The better mini-invasive surgery is the most appropriate surgery. That primarily means the right indication. Do enough and not too much.”
Neyret discussed unicompartmental knee arthroplasty (UKA), while David A. Parker, FRACS, presented pros and cons of MIS TKA.
“Mini-incision TKA has been heavily marketed by companies and promoted largely from a number of centers in the United States with little scientific evidence to substantiate claims of markedly improved results,” Parker said. But what is happening is not all negative, he added.
Neyret performs about 150 TKAs and 25 UKAs, annually. He presented results of a study of 253 cemented UKA prostheses (P Uni; Tornier) implanted via either a medial or lateral approach. The prosthesis has an all-polyethylene tibial component.
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| This woman underwent a lateral unicompartmental knee replacement 7 years ago, followed up with a medial bi-uni knee replacement 2 years ago. Images: Neyret P | |
TKA vs. UKA
Of 144 patients followed more than 2 years, 84 had a medial UKA and 60 underwent UKA in the lateral compartment (116 women, 28 men). Few patients had complications; about 9% required revision.
Neyret reported 95.2% were satisfied or very satisfied with the results. Their knee and functional scores improved significantly over time (P<.05); 81% reported occasional or no knee pain postoperatively.
Although most UKAs are performed in the medial compartment, lateral procedures can also be successful using a surgical approach similar to the medial approach, Neyret explained.
According to a study by Neyret and colleagues in Techniques in Knee Surgery, lateral UKA is indicated for unicompartmental arthritis where reducibility of any frontal deformity is possible and the cruciate ligament is intact. Obesity is a contraindication.
“The patient selection guidelines must be strictly respected to obtain satisfactory results,” they wrote in their abstract.
In some cases of lateral femoropatellar osteoarthritis, a lateral unicompartmental knee replacement can also effectively be combined with a lateral facetectomy, Neyret said.
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Image: Parker DA |
“I can emphasize that education is crucial” for lateral UKA, instrumentation he added, noting that the “helps considerably” to improve bone cut accuracy and component positioning.
Bi-uni TKA
Neyret has also performed five bi-unilateral TKAs — a unicompartmental TKA done in the contralateral compartment of a knee previously treated with a unicompartmental TKA.
“The indication is rare in my practice,” said Neyret, noting bi-unicompartmental knee arthroplasty is not for every surgeon or every patient. “I am certain that only surgeons convinced that uni-TKA could be a simple operation with a short stay at the hospital, short rehabilitation will consider a bi-uni. The others will prefer a subsequent TKA.”
Neyret uses the same implants and instruments for bi-uni knee arthroplasty as for UKA, but does not use navigation. He recommends that surgeons consider performing a bi-uni TKA, use the skin incision from the first surgery and just perform an opposite arthrotomy.
Time will tell
Parker presented the possibility for increased complications with minimally invasive TKA and noted that increased operative time is a big disadvantage of these techniques. But he also credited some newer developments in this area for advancing the field of total joint replacement surgery.
“There are certainly a number of principles of improved soft tissue handling and improved instrumentation that I think are an advance,” Parker told Orthopedics Today. “The role of computer navigation for total knee replacement is becoming well-established in improving accuracy, although more time and study is necessary to show this is reflected in improved outcomes,” he said.
Better survivorship after MIS TKA has not yet been demonstrated, Parker added.
He urged orthopedic surgeons to be objective when deciding whether to incorporate these new surgical techniques into their practices and reminded them any surgery they perform should only be as invasive or traumatic as necessary to achieve the goals but not compromise outcomes.
“Less invasive” is a more appropriate concept to consider than “minimally invasive,” Parker said.
“The use of the computer with less invasive surgery should be complementary in that it should minimize the risk of malalignment resulting from reduced visualization, but it does not substitute for careful surgical technique.”
For more information:
- Christopher E. Ackroyd, FRCS, is a member of the Orthopaedics Today International Editorial Board. He can be reached at Avon Orthopaedic Hospital, 2 Clifton Park, Clifton, Bristol, United Kingdom BS8 3BS; 44-117-973-0958; e-mail: Ackroyd@tesco.net. He received royalties from and is a consultant to Stryker.
- Philippe Neyret, MD, can be reached at Hopital de la Croix Rousse, 8 Rue de Margnolles, Lyon, France 69300; 33-472-071989; e-mail: Philippe.neyret@chu-lyon.fr. He received royalties and a consultant to Tornier.
- David A. Parker, FRACS, can be reached at Sydney Orthopaedic, Arthritis & Sports Med, Level 1, 445 Victoria Ave., Chatswood, Sydney, Australia 2067; 61-2-94117700; e-mail: dparker@sydneyortho.com.au. He has no direct financial interest in any products or companies mentioned in the article.
References:
- Holt G, Wheelan K, Gregori A. The ethical implications of recent innovations in knee arthroplasty. J Bone Joint Surg Am. 2006;88:226-229.
- Neyret P, Verdonk RE, Parker DA. Symposium: ISAKOS Knee Committee: Mini-invasive Knee Arthroplasty—Do we have the evidence to back this up? Presented at the 2007 International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine Congress. May 27-31, 2007. Florence.
- Servien E, Aitsiselmi T, Neyret P, Verdonk P. How to select candidates for lateral unicompartmental prosthesis. Techniques in Knee Surgery. 2007;6(1): 51-59.