[A new technique determining tibial rotational alignment in total knee arthroplasty]

To compare the two different techniques determining tibial rotational alignment in total knee arthroplasty (TKA) to enhance postoperative effect and reduce complications.

From May 2006 to April 2007, 60 patients (27 males, 33 females, aged 55-78 years) received TKA and randomly divided into 2 groups (n=30): tibial rotational alignment in TKA was determined by medical 1/3 of tibial tubercle in Group A, by medial border of tibial tubercle at 0-9 degrees varus in Group B, by medical 1/3 of tibial tubercle at 20 degrees or greater varus or by the mean line between medial border of tibial tubercle and medical 1/3 of tibial tubercle at 10-19 degrees varus. The angle of rotation of polyethylene cushion was calculated.

The angle of rotation of polyethylene cushion in Group A was (8.4+/-3.8) degrees at 0-9 degrees varus, (3.5+/-2.7) degrees at 10-19 degrees varus and (0+/-2.4) degrees at 20 degrees varus or over, respectively, and there was significant difference (P<0.05). The angle of rotation of polyethylene cushion in Group B was (0+/-2.1) degrees at 0-9 degrees varus, (0+/-2.0) degrees at 10-19 degrees varus and (0+/-1.7) degrees at 20 degrees varus or over, respectively, and there was no significant difference (P>0.05). The angle of rotation of polyethylene cushion averaged (5.6+/-2.8) degrees in Group A and (0+/-1.9) degrees in Group B, showing significant difference (P<0.05).

The range of ideal tibial rotational alignment in TKA was from medial border of the tibial tubercle to medical 1/3 of the tibial tubercle, and is decided by the degree of varus deformities and valgus deformities.