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báo cáo hóa học:" Accuracy of acetabular cup positioning using imageless navigation"

Tuyển tập các báo cáo nghiên cứu về hóa học được đăng trên tạp chí sinh học quốc tế đề tài : Accuracy of acetabular cup positioning using imageless navigation | Hohmann et al. Journal of Orthopaedic Surgery and Research 2011 6 40 http www.josr-online.eom content 6 1 40 JOURNAL OF ORTHOPAEDIC SURGERY AND RESEARCH RESEARCH ARTICLE Open Access Accuracy of acetabular cup positioning using imageless navigation Erik Hohmann1 2 Adam Bryant3 and Kevin Tetsworth4 5 Abstract Background Correct placement of the acetabular cup is a crucial step in total hip replacement to achieve a satisfactory result and remains a challenge with free-hand techniques. Imageless navigation may provide a viable alternative to free-hand technique and improve placement significantly. The purpose of this project was to assess and validate intra-operative placement values for both inclination and anteversion as displayed by an imageless navigation system to post-operative measurement of cup position using high resolution CT scans. Methods Thirty-two subjects who underwent primary hip joint arthroplasty using imageless navigation were included. The average age was 66.5 years range 32-87 . 23 non-cemented and 9 cemented acetabular cups were implanted. The desired position for the cup was 45 degrees of inversion and 15 degrees of anteversion. A pelvic CT scan using a multi-slice CT was used to assess the position of the cup radiographically. Results Two subjects were excluded because of dislodgement of the tracking pin. Pearson correlation revealed a strong and significant correlation r 0.68 p 0.006 for cup inclination and a moderate non-significant correlation r 0.53 p 0.45 between intra-operative readings and cup placement for anteversion. Conclusions These findings can be explained with the possible introduction of systematic error. Even though the acquisition of anatomic landmarks is simple they must be acquired with great precision. An error of 1 cm can result in a mean anteversion error of 6 degrees and inclination error of 2.5 degrees. Whilst computer assisted surgery results in highly accurate cup placements for inclination anteversion of the cup .