Computed tomography-based navigation to determine the socket location in total hip arthroplasty of an osteoarthritis hip with a large leg length discrepancy due to severe acetabular dysplasia.
ABSTRACT For osteoarthritis hips due to severe acetabular dysplasia such as Crowe type 3 or 4, placement of the socket is a difficult procedure in total hip arthroplasty. Because the acetabular bone stock is poor, suitable location for the socket is very limited with respect to achieving good coverage with the host bone. A 51-year-old woman who had an osteoarthritis hip with a large leg length discrepancy due to severe acetabular dysplasia required total hip arthroplasty. The purpose of the total hip arthroplasty was to improve the hip disorder as well as to reduce the leg length discrepancy to achieve good gait function. We present technical solutions to aid the surgeons in placing the acetabular socket at the proper location by using computed tomography-based navigation system.
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ABSTRACT: Using a total of 30 cadaveric hips, the accuracy of a fluoroscopy-based computer navigation system for cup placement in total hip arthroplasty (THA) was investigated and an error analysis was carried out. The accuracy of placing the acetabular component within a predefined safe zone using computer guidance was compared to the precision that could be achieved with a freehand approach. Accurate control measurements of the implanted cup were obtained using fiducial-based matching to a pre-operative CT scan with respect to the anterior pelvic plane. A significantly higher number of cups were placed in the safe zone with the help of the navigation system. The variability of cup placement could be reduced for cup abduction but not substantially for cup version. An error analysis of inaccurate landmark reconstruction revealed that the registration of the mid-pubic point with fluoroscopy was a potential source of error. Keeping this pitfall in mind, fluoroscopy-based navigation in THA is a useful tool for registration of the pelvic coordinate system, particularly those points that cannot be reached by direct pointer digitization with the patient in the lateral decubitus position.Computer Aided Surgery 01/2005; 10(5-6):329-36. · 0.78 Impact Factor
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ABSTRACT: Correct orientation of the cup optimizes the range of motion of total hip arthroplasty (THA) and reduces the risk of dislocation, wear, impingement,and pelvic osteolysis. Therefore, CT-based navigation is used to position the acetabular cup precisely in a planned orientation relative to predefined bony landmarks in order to increase the function and longevity of THA. Fourteen patients were operated on using CT-based navigation for acetabular cup positioning. After scanning the patient's pelvis in a preoperative CT, a3-D plan was developed before surgery. Intraoperatively, the CT/3-D model is registered to coincide with the actual position of the patient on the operating table. Mean time for surgery increased by an average of 46 minutes and mean blood loss increased by 140 ml. Positioning of the cup was optimized, ie, it was close to the predefined target. There were no complications related to the use of CT-based navigation. Due to some technical failures at the beginning, two operations were completed manually. CT-based navigation greatly enhanced the precision of cup positioning,thus eliminating malpositioning. Although CT-based navigation does support the surgeon in controlling cup orientation, it increases time for surgery, blood loss, radiation of the patient, and total costs of the whole procedure. Furthermore,navigation of the acetabular cup alone is not sufficient for optimizing the range of motion in THA.Injury 07/2004; 35 Suppl 1:S-A84-9. · 1.93 Impact Factor