[5-year follow-up study of total knee arthroplasty by means of EMG mapping].

Aim: The objective of the present study was to evaluate the long-term functional results after implantation of a total knee arthroplasty (TKA) objectively and quantitatively.

Method: Functional parameters (muscular coordination, strength and range of motion) and the subjective satisfaction of the patients were measured by means of EMG mapping, isokinetics, ultrasound and a questionnaire in 21 patients with TKA 5.1 years after implantation of the TKA.

Results: 81 % of the investigated patients were subjectively satisfied. The isokinetic results showed a significant improvement of the extensor strength and of the relation between flexors and extensors. Patients who had been more physically active over these 5 years reached significantly better results. The results of EMG mapping showed good overall retention of the satisfactory coordination levels resulting from the initial in-patient rehabilitation. But the coordination patterns demonstrated clear changes showing highly activated areas in the region of the M. vastus medialis. The range of motion and the contraction capacity showed no further improvement compared with the results 26 weeks after implantation of the TKA.

Conclusion: Long-term results after implantation of a TKA showed a good muscular coordination, strength and range of motion. A higher physical activity level led to better functional results and greater overall satisfaction of TKA patients 5 years after implantation.