We conclude that motivation and other patient related factors, the implant and the surgeon itself influence the result much more than the approach used for total hip replacement.
Referencing the tibial rotation on a line from the lateral border of the medial third of the tibial tubercle to the center of the tibial tray resulted in a better femoro-tibial alignment than using the medial border of tibial tubercle as landmark. Surgeons using fixed bearings with a high conformity between the inlay and the femoral component should be aware of this effect to avoid premature polyethylene wear.
The femoral component showed a median deviation from the transepicondylar axis of 1,7° (range: 3,1° external rotation to 4,4° internal rotation) in the navigated group and of 1,0° (range: 3,4° external rotation to 4,3° internal rotation) in the conventional implantations. The tibial component showed a much greater range of rotational deviation from the medial third of the tuberosity in median 5,3° (range: 14,9° external rotation to 26° internal rotation) in the navigated group and 4,8° (range: 6,5° external rotation to 23,8° internal rotation) in the conventional implantations.
A total of 186 patients with posttraumatic anterior instability could be clinically re-examined within 1 to 5 years after initial surgery, among which 147 patients underwent an open and 39 patients an arthroscopic Bankart procedure. The median age of this sample was 27 years (interquartile range 21 – 37 years) at initial surgery, 21% of these patients were female.
ROM showed no difference between open and arthroscopic Bankart procedure for abduction and a mild difference for external rotation. 21 of 115 (18%) patients had an external rotation lag of 20° or more after open surgery versus 1 of 34 (3%) after arthroscopic treatment (Fisher p=0,027). The Rowe score demonstrated “good” or “excellent” functional results in 102 of 117 (87%) patients versus 28 of 35 (80%) patients after open versus arthroscopic treatment (Fisher p=0,285).
After obtaining informed consent, 80 patients were randomised to undergo a navigated or conventional total knee replacement. All received a cemented, unconstrained, cruciate-retaining implant with a rotating platform. Full-length standing and lateral radiographs and CT scans of the hip, knee and ankle joint were carried out five to seven days after operation. No notable differences were found between computer-assisted navigation and conventional implantation techniques as regards the rotational alignment of the femoral or tibial components. Although the deviation from the transepicondylar axis was relatively low, there was a considerable range of deviation for the tibial rotational alignment. There was no statistically significant difference regarding the occurrence pattern of outliers in mechanical malalignment but the number of outliers was reduced in the navigated group.