title: Computed tomography-based surgical navigation for hip arthroplasty.
abstract: Component malpositioning and postoperative leg length discrepancy are the most common technical problems associated with total hip arthroplasty (THA). Surgical navigation offers the potential to reduce the incidence of these problems. We reviewed 317 patients (344 hips) that underwent THA using computed tomography-based surgical navigation, including 112 THAs using a simplified method of measuring leg length. Guided by the navigation system, cups were placed in 40.8 degrees +/- 2 degrees of operative abduction (range, 35 degrees -50 degrees) and 30.8 degrees +/- 3.2 degrees (range, 19 degrees -43 degrees) of operative anteversion. We subsequently measured radiographic abduction on plain anteroposterior pelvic radiographs and calculated abduction and anteversion. Radiographically, 97.1 % of the cups were in the safe zone for abduction and 92.4% for anteversion. The mean incision length was less than 8 cm for 327 of the 344 hips. Leg length change measured intraoperatively was 6.6 +/- 4.1 mm (range, -2-22), similar to measurements from the pre- and postoperative magnification-corrected radiographs. Computer assistance during THA increased the consistency of component positioning and allowed reliable measurement of leg length change during surgery.
authors: Center for Computer-Assisted and Reconstructive Surgery, New England Baptist Hospital and Tufts University School of Medicine, Boston, MA 02120, USA.
authors: Timo M
authors: TM
authors: Ecker
authors: Moritz
authors: M
authors: Tannast
authors: Stephen B
authors: SB
authors: Murphy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D021621:Imaging, Three-Dimensional; D007870:Leg Length Inequality / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011857:Radiographic Image Interpretation, Computer-Assisted; D016059:Range of Motion, Articular; D020127:Recovery of Function; D015203:Reproducibility of Results; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome