Minimally invasive total knee replacement, such as Zimmer’s Nexgen MIS Knee Implants, involving a smaller incision than standard knee replacement surgery, have recently been questioned by orthopedic surgeons at the American Association of Orthopedic Surgery’s Annual Meeting 2009.

Zimmer’s Nexgen MIS system comes with two sizes of tibial stems, either of which is assembled in-vivo, facilitating minimally invasive surgery.

The procedure, known as “MIS”, involves a smaller 4"-6" incision than the standard knee replacement surgery’s average 8"-10" incision. The surgical procedure is promoted as causing less damage to the tissue surrounding the knee, resulting in a shorter hospital stay, shorter recovery, and even a better-looking scar. While it is possible to implant certain manufacturer’s smaller prostheses through the smaller incision, questions have arisen as to whether the surgery can be performed as well as with the traditional approach, which allows for excellent visualization, component orientation, fixation, and has been associated with remarkable long-term implant survival.

Preliminary independent studies have shown a higher rate of complications with MIS, including poorer positioning of the knee implants, often causing revision surgery within two years.

Short-term results of the MIS procedure claim the advantages of less blood loss, shorter hospitalization, earlier return of function, earlier independent straight leg raise, higher level of patient satisfaction, ability to perform surgery on outpatient basis, increased cost-effectiveness, less need for inpatient rehabilitation post-discharge, less need for assistive devices, a lower incidence of lateral release, and increased range of motion in the short term.

However, most short term studies have been reported by designers and/or advocates of the techniques or systems, or highly experienced specialists in knee surgery. The extent of the surgeon’s training or experience performing MIS may be a potential factor in the high number of early failures, although even leading surgeons have experienced serious complications. Higher complication rates have arisen when the technique is performed by lower-volume surgeons or lower-volume centers. In a study presented at the AAOS Annual Meeting in 20091 of revision knee surgeries performed by five surgeons at three surgical centers over a three year period, 18.6% of the failed implants studied were found to have been originally placed using the MIS approach. Patients who had originally had an MIS approach had a significantly shorter average time before revision surgery was required, due primarily to greater tibial varus, which correlates with increased wear of the polyethylene insert and component loosening. Other complications include less consistent component alignment and longer operative times.

If you are experiencing complications after implantation of a knee prosthesis using a device implanted using the MIS procedure, you may be entitled to recover damages including the medical bills associated with revision surgery. Knee Prostheses designed for use in Minimally Invasive Surgery include the Zimmer Nexgen MIS, Wright Advance with Odyssey Instrumentation, Biomet Vanguard with Microplasty Instrumentation, Smith & Nephew Genesis II Stryker Triathlon PKR, and DePuy Sigma.

If you or someone that you know have been injured or worse as a result of using the MIS procedure, please contact the law offices of Houssiere, Durant & Houssiere, LLP to set up a free consultation with an attorney and medical expert. The attorneys and medical staff at Houssiere Durant and Houssiere LLP have decades of experience in bringing successful suits against medical device companies and is aggressively handling claims against manufactures who have produced and marketed defective implants.