The goal of less invasive knee replacement surgery is to reduce cutting and trauma to the knee's soft tissues. Some studies show short-term functional outcomes are good, meaning that patients tend to experience less post-surgical pain and regain the use of their knees in a shorter period of time.

See What to Expect After Knee Replacement

Long-term differences are less clear. 1 Stevens-Lapsley JE, Bade MJ, Shulman BC, Kohrt WM, Dayton MR. Minimally Invasive Total Knee Arthroplasty Improves Early Knee Strength But Not Functional Performance: A Randomized Controlled Trial. J Arthroplasty. 2012 Mar 27. [Epub ahead of print] PubMed PMID: 22459124; PubMed Central PMCID: PMC3413785. , 2 "Minimally Invasive and Small Incision Joint Replacement Surgery: What Patients Should Consider." The Knee Society. PDF. ©2005, last reviewed January 2008. Accessed September 17, 2012. It may take many years and dozens of more clinical studies before minimally invasive procedures are shown to have definitively better or worse outcomes than traditional procedures. 3 T. Karachalios, D. Giotikas, N. Roidis, L. Poultsides, K. Bargiotas, and K. N. Malizos, "Total knee replacement performed with either a mini-midvastus or a standard approach: a prospective randomized clinical and radiological trial," Journal of Bone and Joint Surgery B, vol. 90, no 5, pp 584-591, 2008. , 4 Khanna A, Gougoulias N, Longo UG, Maffulli N. Minimally invasive total knee arthroplasty: a systematic review. Orthop Clin North Am. 2009 Oct;40(4):479-89, viii. Review. PubMed PMID: 19773053. , 5 Peter M. Bonutti, Michael G. Zywiel, Slif D. Ulrich, D. Alex Stroh, Thorsten M. Seyler, Michael A. Mont; A Comparison of Subvastus and Midvastus Approaches in Minimally Invasive Total Knee Arthroplasty. The Journal of Bone & Joint Surgery. 2010 Mar;92(3):575-582. doi: 10.2106/JBJS.I.00268

Until more research is done, the decision to have minimally invasive knee replacement surgery must be made on a case-by-case basis. The patient and doctor must consider the pros and cons of minimally invasive surgery as well as other factors, such as whether or not the patient is a good candidate for the surgery, the cost of surgery and recovery time, and the surgeon's experience. These topics are discussed below.

See also Facts and Considerations for Total Knee Replacement


Patient Eligibility for Minimally Invasive Knee Replacement

Total knee replacement is a treatment option for patients whose daily activities are affected by moderate to severe knee arthritis. Traditional knee replacements are available to patients who are healthy enough to undergo surgery, regardless of age or weight. In contrast, minimally invasive knee replacement surgeries tend to have higher complication rates for some people, and therefore prospective patients must meet additional criteria to be eligible.

The best candidates for minimally invasive knee replacement surgery tend to be:

  • Younger (though opinions vary, this generally means patients younger than 65 years).
  • Thin, not obese or overly muscular.
  • Small or medium framed. Those who need larger sized implants seem to have more complications.
  • Without bone and joint deformity, such as severe osteoporosis, knock-knees or bow-legs.
  • Motivated and well-informed about their surgery and rehabilitation.

Patients can investigate their options by seeking a second or third opinion from other surgeons. Ultimately, even if a patient is deemed a good candidate for minimally invasive surgery, it is up to the patient to decide whether to have minimally invasive knee replacement, traditional knee replacement, or no surgery at all.

See Orthopedic Surgeon for Arthritis Treatment


Cost of Minimally Invasive Knee Replacement Surgery

Another potential advantage is financial. A faster recovery and shorter hospital stay translate into thousands of dollars in medical bill savings compared with traditional knee replacement surgery. 6 "Evidence report: minimally invasive surgery for total knee replacement." ECRI Institute, Health Technology Assessment Information Service. April 2011. Accessed September 24, 2012. However, patients who are covered by Medicare or private insurance might see zero or only a small percentage of medical bill savings. (Also, some insurance companies may still consider minimally invasive knee replacement surgery to be "experimental" and not cover it at all. Patients are advised to check with their insurance carriers.)

In addition to medical costs, patients who work may take into account lost wages during their recovery periods. Patients who are able to return to work sooner will experience a shorter lapse in earnings.

Choosing a Surgeon

There is no specific credentialing system that certifies orthopedic surgeons to perform minimally invasive techniques for knee replacement. 6 "Evidence report: minimally invasive surgery for total knee replacement." ECRI Institute, Health Technology Assessment Information Service. April 2011. Accessed September 24, 2012. Therefore, a patient should ask a surgeon:

  • How often does the surgeon perform this specific surgery?
  • What are the surgeon's success and complication rates regarding the specific procedure?
  • What are the possible short- and long-term outcomes?

When weighing the advantages and risks of minimally invasive knee replacement, a surgeon's experience and success with a specific procedure should be considered. 6 "Evidence report: minimally invasive surgery for total knee replacement." ECRI Institute, Health Technology Assessment Information Service. April 2011. Accessed September 24, 2012. , 7 Katz JN, Barrett J, Mahomed NN, Baron JA, Wright RJ, Losina E. Association between hospital and surgeon procedure volume and the outcomes of total knee replacement. J Bone Joint Surg Am. 2004 Sep;86-A(9):1909-16. PubMed PMID: 15342752.

Dr. Vivek Sood is an orthopedic surgeon specializing in joint replacement, reconstructive surgery, foot and ankle, and outpatient total knee surgery. He practices at Bay Area Orthopaedics & Sports Medicine. He went on to receive advanced training in adult joint reconstruction at Rush University Medical Center and in foot and ankle surgery at Mount Sinai Medical Center.