Minimally invasive and standard total knee arthroplasty result in similar clinical outcomes at a minimum of five-year follow-up.

ABSTRACT

BACKGROUND: Although a minimally invasive total knee arthroplasty (MIS-TKA)fails to show superior short-term clinical results over a standard technique, the longer-term outcomes remain unknown. OBJECTIVE: Evaluate the intermediate clinical outcomes of MIS-TKA, comparing to those of standard technique. MATERIAL AND METHOD: The authors retrospectively collected data from the patients who underwent uncomplicated total knee arthroplasty between March 2004 and December 2005. Patients with a body mass index (BMI) over 30 kg/m2 or with severe deformity and those who required a complex surgical procedure were excluded. Patients were divided into 2 groups based on the surgical approach: 27patients (31 knees) and 26 patients (33 knees) for the MIS-TKA and standard TKA, respectively. Pre- and perioperative data were collected. Clinical and functional outcomes were followed-up to a minimum of 5 years. RESULTS: The means follow-up in the MIS- and standard TKA groups were 73 and 74 months, respectively. Pre- and perioperative data did not show any differences between the two groups except for more females and lower BMI in the MIS-TKA group. At 2- and 5-year post-operative follow-up, the knee society pain and functional scores improved significantly in both groups (p < 0.001). There were no differences in the postoperative alignment, range of motion and the knee society scores between MIS- and standard TKA. In addition, post-operative complications were similar in both groups (2 manipulations under anesthesia and 1 traumatic rupture of patellar tendon in each group). CONCLUSION: The present study showed that there were no differences in the intermediate-term post-operative function between MIS-TKA and standard TKA in a well-selected patient population. Thus, orthopedic surgeons should not compromise their surgical exposure by using small and unfamiliar surgical technique. Since MIS-technique may increase the postoperative complication rate, a long-term study to evaluate the results of MIS-TKA is still needed.