[Analysis of short-term results of post total knee arthroplasty using TC-Dynamic posterior stabilized prostheses]

To assess the feasibility, safety, and validity of the TC-Dynamic posterior stabilized prostheses implanted in the total knee arthroplasty (TKA).

Twelve knees of 10 patients (the TC-Dynamic group) were followed up, who had been implanted with the TC-Dynamic posterior stabilized prostheses from September 2003 to March 2004. Preoperative KSS knee scores were 16.08 +/- 11.58, function scores 13.75 +/- 19.79, and the range of motion (ROM) of the knee 75.00 +/- 26.46 degrees. Meanwhile, 50 knees of 30 patients (the Scorpio group) were followed up, who had undergone TKA with the Scorpio posterior stabilized prostheses. Preoperative KSS knee scores were 19.48 +/- 9.67, function scores 3.16 +/- 19.82, and the ROM of the knee 80.80 +/- 22.82 degrees. The anteroposterior and lateral X-ray films of each knee were examined before and after operation. The statistical Z-test was used to analyze the differences between the 2 groups in the improvement of the KSS knee scores, function scores, and ROM after operation.

The average of the 130 days' follow-up revealed that the patients implanted with the TC-Dynamic prostheses had an excellent result. In the TC-Dynamic group, the KSS knee scores were 88.83 +/- 4.04 with improved scores of 72.75 +/- 14.47 compared with those before operation; function scores were 79.17 +/- 5.15 with improved scores of 65.42 +/- 19.47; the ROM of the knee was 107.92 +/- 11.57 degrees with increased degrees of 32.92 +/- 32.22 degrees. Meanwhile, in the Scorpio group, the KSS knee scores were 85.68 +/- 7.36 with improved scores of 66.20 +/- 10.44 compared with those before operation; function scores were 71.40 +/- 12.70 with improved scores of 68.24 +/- 25.35; the ROM of the knee was 109.20 +/- 11.13 degrees with increased degrees of 28.40 +/- 26.41 degrees. There was no significant difference in the improvement of the KSS knee scores, function scores, and ROM after operation between the 2 groups (P > 0.01). All the X-ray films of the knees implanted with both the Scorpio prostheses and the TC-Dynamic prostheses were analyzed. No mal-alignment or lucent line with the prostheses was seen in all these X-ray films.

The short-term follow-up indicates that the patients implanted with the TC-Dynamic prostheses have an excellent result. The TC-Dynamic prostheses with a scientific and proper design is more suitable for the Chinese. However, the long-term outcome of the patients implanted with the TC-Dynamic prostheses should be observed in a larger number of TKA operations. The basic surgical principles, including excision of both the cruciate ligaments and correction of the bone deformity with the proper balancing of the soft tissues in flexion and extension, are still crucial to successful TKA and to the long-term high survival rate of the knee prostheses.