[Minimally invasive and navigated implantation for total knee arthroplasty: X-ray analysis and early clinical results].

Total knee arthroplasty (TKA) alignment is one of the most important factors in long-term prosthesis survival. Minimally invasive surgical (MIS) procedures are becoming more common. There may be an increased overall complication rate, especially component malpositioning, due to poor visualisation. The disadvantage of restricted visualisation in the less invasive technique can be compensated by a navigation system. This combined procedure is described in this paper. A total of 40 Search Evolution TKAs were implanted using OrthoPilot navigation in the standard manner, and 40 TKAs were implanted using MIS via a subvastus approach. Primary osteoarthritis of the third or fourth degree, without severe valgus deformity, was the indication. These patients were then selected at random as they came to the institution. The results were evaluated radiologically and clinically.Pain, range of motion, gait and function, and the entire clinical score 10 days after the operation were significantly better in the MIS-group. At 6 and 12 weeks postoperatively, these results were no longer statistically significant. Ideal radiological results were obtained in all cases. No differences in limb axis and component alignment were found after the operation between the navigated groups. MIS is technically very demanding. That is why it should be used only in carefully selected cases. Its advantages occur in the first weeks after the surgery. The long-term results must still be determined.