Hip Int ( 2010 ; : 01) 14 -17 20 © 2010 Wichtig Editore - ISSN 1120-7000 14 14 ORIGINAL ARTICLE INTRODUCTION The aim of hip arthroplasty is to optimize function and to restore leg length and femoral offset. As hip anatomy is highly variable, a careful assessment of leg length and femoral head offset is needed to reproduce normal hip biomechanics. Leg length discrepancy following total hip arthroplasty is a significant source of patient dissatisfac- tion (1). Therefore preoperative planning for total hip ar- throplasty is essential for a successful outcome (2). Digital images using PACS (Picture archiving and communication system) have replaced standard printed films for templat- ing in the UK. Various software packages are employed (3, 4). Digital templating is a method of determining the size and positioning of the prosthesis within the bone to optimise function of the joint. It provides a permanent, ar- chived record of the templating process. Bone conservation makes hip resurfacing an attractive conservative option in the treatment of end-stage arthritis of the hip in young and active patients. The advantages of Birmingham hip resurfacing (BHR) over Total hip re- placement (THA) may result from an increased safe range of movement because of the larger femoral head and en- hanced stability (5). A recent study by Loughhead et al showed that resurfacing does not significantly alter leg length or offset (6). One of the factors which influences the success of BHR is the use of the optimum implant size. The aim of our study was to determine the usefulness of preoperative digital templating in estimating implant sizes in Birmingham hip resurfacing. Preoperative digital templating of Birmingham hip resurfacing Sujith Konan, Faizal Rayan, Geert Meermans, Jan Geurts, Fares S. Haddad Department of Trauma and Orthopaedics, University College Hospital, London - UK ABSTRACT. The aim of our study was to determine the usefulness of preoperative digital templating of Birmingham hip resurfacing (BHR). This prospective cohort of 30 consecutive Birmingham hip resurfacings was templated digitally by two senior hip arthroplasty fellows (GM, JG) independently. A blinded observer then collated information on the actual implant sizes intraoperatively and used this to statistically analyse the correlation (Interclass correlation coefficient) between the digitally templated implant sizes and the actual implant sizes used. A significantly high rate of coincidence between digi- tally templated estimates and the actual implant sizes was noted for both groups of templates. The In- tra class correlation coefficient (ICC) for the acetabular cup in the two groups were 0.798, p=0.013 and 0.870, p=0.0001. For the femoral component, the ICC values in the two groups were 0.888, p=0.005 and 0.784, p=0.003. Similarly a high reliability of digital templating was noted for both acetabular (0.823, 0.888) and femoral components (0.777, 0.8132). In conclusion, digital templating can reliably estimate implant sizes in Birmingham hip resurfacing. KEY WORDS. Birmingham hip resurfacing, Digital templating, Preoperative planning Accepted: July 16, 2009