The accuracy of free-hand cup positioning--a CT based measurement of cup placement in 105 total hip arthroplasties.
We studied 105 patients who received a total hip arthroplasty between June 1985 and August 2001 using freehand positioning of the acetabular cup. Using pelvic CT scan and the hip-plan module of SurgiGATE-System (Medivision, Oberdorf, Switzerland), we measured the angles of inclination and anteversion of the cup. Mean inclination angle was 45.8 degrees +/-10.1 degrees (range: 23.0-71.5 degrees ) and mean anteversion angle was 27.3 degrees +/-15.0 degrees (range: -23.5 degrees to 59.0 degrees ). We compared the results to the "safe" position as defined by Lewinnek et al. and found that only 27/105 cups were implanted within the limits of the safe position. We conclude that a safe position as defined by Lewinnek et al. [13] was only achieved in a minority of the cups that were implanted freehand.
Department of Orthopaedic Surgery, University of Duisburg--Essen, Hufelandstrasse 55, 45122, Germany. guido.saxler@uni-essen.de
G
G
Saxler
A
A
Marx
D
D
Vandevelde
U
U
Langlotz
M
M
Tannast
M
M
Wiese
U
U
Michaelis
G
G
Kemper
P A
PA
Grützner
R
R
Steffen
M
M
von Knoch
T
T
Holland-Letz
K
K
Bernsmann
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D036542:Tomography, Spiral Computed / Q000295:instrumentation*; D016896:Treatment Outcome