Minimally Invasive and Standard Total Knee Arthroplasty Result in Similar Clinical Outcomes at a Minimum of Five-Year Follow-Up
Aasis Unnanuntana MD* Chaturong Pornrattanamaneewong MD*, Christopher S. Mow MD**
Affiliation : * Department of Orthopaedic Surgery, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand ** Department of Orthopaedic Surgery, Stanford Hospitals and Clinics, Stanford, CA, USA
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: 27 patients (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 post-
operative complication rate, a long-term study to evaluate the results of MIS-TKA is still needed.
Keywords : Minimally invasive surgery (MIS), Total knee arthroplasty, Clinical outcome, Intermediate-term result
