[Comparison of short-term result between high-flex and conventional posterior-stabilized prosthesis in total knee...

To compare the short-term result between the high-flex (HF) and conventional posterior-stabilized (PS) prosthesis in total knee arthroplasty (TKA).

From April 2005 to October 2007, 23 cases (27 knees) underwent TKA by HF prosthesis (HF group), and 35 cases (41 knees) underwent TKA by PS prosthesis (PS group). In HF group, there were 2 males (3 knees) and 21 females (24 knees) aged (64.3 +/- 5.6) years, including 20 cases (23 knees) of osteoarthritis and 3 cases (4 knees) of rheumatoid arthritis; body mass index (BMI) was 27.3 +/- 3.9; the course of disease was (5.3 +/- 5.6) years; the Hospital for Special Surgery Scoring System (HSS) score was 58.4 +/- 7.9; the Western Ontario and McMaster universities osteoarthritis index (WOMAC) score was 49.4 +/- 6.9; the maximum knee flex degree was (107.6 +/- 8.3) degrees; and the range of knee motion was (103.5 +/- 7.7) degrees. In PS group, there were 3 males (3 knees) and 32 females (38 knees) aged (65.1 +/- 5.9) years, including 33 cases (39 knees) of osteoarthritis and 2 cases (2 knees) of rheumatoid arthritis; BMI was 27.1 +/- 4.1; the course of disease was (5.1 +/- 4.9) years; HSS score was 60.1 +/- 10.4; WOMAC score was 47.9 +/- 7.2; the maximum knee flex degree was (108.4 +/- 9.7) degrees; and the range of knee motion was (105.9 +/- 11.4) degrees. There were no significant differences in general data between two groups (P > 0.05).

All incisions achieved healing by first intention. No complication of ankylosis, blood vessel and nerve injuries, and prosthesis loosening occurred. All patients were followed up for 24-54 months (average 32.8 months). There were no significant differences in the HSS score, WOMAC score, the maximum knee flex degrees, and the range of knee motion at 3, 12, and 24 months after operation between two groups (P > 0.05), but there were significant differences between pre- and post-operation (P < 0.05). Anterior knee pain occurred in 1 case of HF group and 4 cases of PS group after 24 months, the incidence rates were 3.70% in HF group and 9.76% in PS group, showing significant difference (P < 0.05). The X-ray films showed that no lucent zone around prosthesis and no patella baja were observed, and the force line was excellent.

There is no significant difference in the range of knee motion and clinical scores between the HF prosthesis and the PS prosthesis, but the former's incidence rate of anterior knee pain is lower.