Cross table lateral radiography for measurement of acetabular cup version.
BACKGROUND
Appropriate orientation of the acetabular cup is an important factor for long-term results of total hip arthroplasty. For measurement of cup version cross-table lateral radiography is frequently used, but the reliability has been questioned. We compared cross table lateral radiography with computed tomography in patients that had undergone primary total hip arthroplasty.


METHODS
The study was prospectively done in 117 patients (117 hips). At 3 months after total hip replacement the acetabular version was measured by cross table lateral radiography and compared to measurements by computed tomography.


RESULTS
By cross table lateral radiography acetabular anteversion was on mean 13.9° with a standard deviation of 10.1° as compared to 17.8°±12.6° by computed tomography. Mean difference was -3.8 with a distribution of measurements of ±13 degrees for 95% of the cases.


CONCLUSIONS
Our study shows that cross table radiography provides acceptable information for clinical use, but has limited use for precise analysis of acetabular cup version.
1 Department of Orthopedics, 2 Department of Radiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Olav
O
Reikeras
1 Department of Orthopedics, 2 Department of Radiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Ragnhild Beate
RB
Gunderson
Accuracy; acetabular component; measurement; precision; total hip; version angle