No Advantage with Minimally Invasive Knee Replacement

Physical Therapy in Twin Falls and Buhl for Knee

Are you thinking about having a knee replacement? Wondering whether to stick with the standard surgical procedure or go for the minimally invasive technique? The results of this study concur with others that there really isn't an advantage of one over the other.

That may surprise you since it would make sense that a smaller incision would be better. With a minimally invasive approach, there's less disruption of the surrounding soft tissues and less blood loss.

Some studies have shown that there is a benefit with minimally invasive total knee replacement early on in the post-op period. Patients report less pain, faster recovery of knee motion, and shorter stay in the hospital. But there are other studies that fail to show any benefit of the minimally invasive technique compared to the conventional (full incision) approach.

Where does that leave us? More study is needed until the question of which is better (safer and more effective) can be answered. This present study offers some information when comparing the minimally invasive approach (without computer navigation) with conventional knee arthroplasty. Arthroplasty is another term for replacement.

Patients included were first time knee surgeries. Surgeons who participated had experience performing minimally invasive knee arthroplasties (replacements). The surgeries were performed by several different surgeons at different surgical sites.

Post-operative care and rehab was the same for all patients regardless of the group (conventional versus mini). Discharge from the surgical center or hospital took place on the eighth day. Patients were sent to a rehab unit where they continued their rehabilitation for another two to three weeks before going home.

Results were measured by comparing range-of-motion, pain levels, function scores, and ability to complete daily chores and activities. X-rays were also compared from before to after surgery. Knee implant position and angles were measured using the X-rays to get an idea of the alignment of the knee joint.

After reviewing and comparing all values for each patient group, it was determined that there simply weren't differences in outcomes between the groups. In other words, no advantage was seen with one technique over the other. Does it just boil down to cosmetics then with a smaller incision?

Some experts say that when there is less blood loss (with the minimally invasive technique), there is less risk of infection, shorter hospital stays, and a lower chance of needing a blood transfusion. In this study, there were an equal number of post-operative complications reported between the two groups. So the theoretical advantage of less blood loss was not seen in this study.

Likewise, the minimal gains in motion seen in the minimally invasive group evened out by the time patients were discharged. By day eight, range-of-motion was equal between the two groups. At the six week check-up, there was no significant difference in pain, motion, and function among all the participants.

The authors ended this study a year early because of the remarkable lack of significant differences between the two groups at the end of the first year. They suggest that the minimally invasive approach to total knee replacement doesn't offer significant benefits over the more traditional or conventional approach.

Minimally invasive techniques require additional training on the part of the surgeon. Implant alignment can be a problem for less experienced surgeons. Clinical results appear to be equal between the standard, conventional approach when compared with the minimally invasive surgery. The results of this study don't support the use of minimally invasive knee replacement over the standard surgery.

Reference: N. Wülker, PhD, MD, et al. A Prospective Randomized Study of Minimally Invasive Total Knee Arthroplasty Compared with Conventional Surgery. In The Journal of Bone and Joint Surgery. July, 2010. Vol. 92-A. No. 7. Pp. 1584-1590.

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