Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties

Table 1

Landmark errors in millimeters between RSA and CT data and between RSA double examinations after rigid body fitting. For the RSA double examinations markers with an error of the rigid body fitting above 0.35 mm are excluded automatically by the software. This is not the case for the comparison between RSA and CT.

Volume	Mean error	Median	Standard deviation	Minimum	Maximum	95% confidence interval
RSA-CT
Markers in bone	0.27	0.22	0.17	0.02	1.50	0.00–0.61
Markers in prosthesis	0.22	0.18	0.16	0.04	1.08	0.00–0.53
RSA1-RSA2 (double examination)
Markers in bone	0.09	0.07	0.06	0.02	0.26	0.00–0.20
Markers in prosthesis	0.11	0.09	0.06	0.02	0.26	0.00–0.24