Inter- and intra-operator reliability in patient-specific template positioning for total hip arthroplasty: A cadaver study

Background: The implantation of the acetabular cup essentially determines the clinical outcome of total hip arthroplasty. To address this issue, the aim of this study was to build patient-specific instruments (PSIs) with various reference surfaces, followed by in vitro investigations to examine the inter- and intra-operator reliability as well as the overall precision of these patient-specific templates. Methods: Seven human hemi-pelvis specimens were used for this study. After a CT scan, PSIs with different imprint heights were created. The overall precision of the templates and the inter- and intra-operator reliabilities were calculated. Results: Strong differences in precision between the PSI designs could be observed. The desired orientation of the acetabular cup could be adjusted with a precision of up to 1.55°. Conclusion: Based on our results, we believe that the application of the PSI-based acetabular cup positioning in total hip arthroplasty procedures can potentially increase the precision of cup placement.