In order to evaluate the short- and long-term clinical and radiological results of MIS in TKA, a prospective randomized trial was designed in our department. All patients admitted to the department under the care of one surgeon specializing in Joint Replacement surgery were assigned to participate in the study, signed a concern form, and randomly allocated into two groups. For patients of group A, a TKA was performed using the mini mid-vastus approach; for patients of group B the surgery was performed using a conventional medial parapatellar incision. The Genesis II prosthesis and MIS instrumentation were used for all patients.

Pre and postoperative clinical and radiological data were collected for all patients at regular time intervals (pre, 1st d, 3rd d, 6th d, 3rd w, 6th w, 3rd m, 6th m, 9th m, 1st y, and every year thereafter). Early postoperative pain was also evaluated using a VAS scale and the ability of early SLR was also recorded.

Until now 80 patients (40 MIS, 40 Controls) have entered the study with a follow-up of more than 6 months. In 5 patients (12.5%) of group A the MIS surgery was abandoned in favor of conventional surgery due to technical problems.

Patients in MIS group A had knees with greater range of motion at 3 w, 6 w and 3 months, better function at 3 and 6 months, and less blood loss. In contrast, the same patients experienced greater pain during the first 3 postoperative days. Surgery lasted 16 minutes more on average for the MIS group A. On radiological evaluation technical errors were observed in 5 patients of MIS group A.