Validity, Reliability and Reproducibility of Plain Radiographic Measurements After Total Hip Arthroplasty

Validity, Reliability and Reproducibility of Plain Radiographic Measurements After Total Hip Arthroplasty

In total hip arthroplasty (THA), radiographic preoperative planning and postoperative evaluation of acetabular component, femoral offset (FO) and leg length discrepancy (LLD) require good validity, interobserver reliability and intraobserver reproducibility.

Questions/purposes: (1) Evaluate the validity of the Sundsvall method of FO measurement by comparing it to a standard FO measurement method. (2) Evaluate the interobserver reliability and intraobserver reproducibility of measurement of FO, LLD, acetabular cup inclination and anteversion.

90 patients with primary unilateral osteoarthritis (OA) were included in this prospective study. On postoperative radiographs FO by the Sundsvall method, FO by a standard method, LLD, acetabular cup inclination and anteversion were measured. The interobserver reliability and intraobserver reproducibility were made by three independent observers. The validity and degree of prediction of Sundsvall method are measured by comparing its results with the standard method.

Inclusion Criteria:

• unilateral total hip replacement with either a cemented Lubinus SP II system (Link, Germany) or an uncemented CLS stem and Triology cup (Zimmer, U.S.A).

Exclusion Criteria:

• Patient with secondary (OA), previous spinal, pelvic, or lower limb injuries or fractures were excluded.