Managing bone loss in acetabular revision.
ABSTRACT The management of bone loss encountered during acetabular revision remains challenging. In order to obtain a successful surgical result, preoperative planning is required to estimate the severity and location of bone defects. Most acetabular revisions can be treated with the use of a cementless hemispherical component. However, a successful surgical reconstruction requires component stability. Depending on the degree of bone loss, the surgical reconstruction may require the use of cancellous or structural bone graft, acetabular augmentation, an acetabular cage, a custom implant, or an acetabular transplant.
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ABSTRACT: BACKGROUND: The Paprosky acetabular defect classification is widely used but has not been appropriately validated. Reliability of the Paprosky system has not been evaluated in combination with standardized techniques of measurement and scoring. QUESTIONS/PURPOSES: This study evaluated the reliability, teachability, and validity of the Paprosky acetabular defect classification. METHODS: Preoperative radiographs from a random sample of 83 patients undergoing 85 acetabular revisions were classified by four observers, and their classifications were compared with quantitative intraoperative measurements. Teachability of the classification scheme was tested by dividing the four observers into two groups. The observers in Group 1 underwent three teaching sessions; those in Group 2 underwent one session and the influence of teaching on the accuracy of their classifications was ascertained. RESULTS: Radiographic evaluation showed statistically significant relationships with intraoperative measurements of anterior, medial, and superior acetabular defect sizes. Interobserver reliability improved substantially after teaching and did not improve without it. The weighted kappa coefficient went from 0.56 at Occasion 1 to 0.79 after three teaching sessions in Group 1 observers, and from 0.49 to 0.65 after one teaching session in Group 2 observers. CONCLUSIONS: The Paprosky system is valid and shows good reliability when combined with standardized definitions of radiographic landmarks and a structured analysis. LEVEL OF EVIDENCE: Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.Clinical Orthopaedics and Related Research 02/2013; · 2.79 Impact Factor
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ABSTRACT: The recent interest in hip resurfacing arthroplasty is motivated by its potential advantages over THA. One advantage of hip resurfacing arthroplasty is that it conserves bone on the femoral side; however, it is unclear whether it does so on the acetabular side. We determined whether the amount of acetabular reaming and acetabular bone removal required for hip resurfacing arthroplasty is equal to, less than, or greater than that for THA. We prospectively evaluated the femoral neck size of 180 hips at the time of primary THA in an identical manner to when carrying out a hip resurfacing arthroplasty. Based on the femoral neck measurement, we determined the minimum cup size that would be used and reamer size required if the hip was undergoing a resurfacing. We compared this to the reamer size actually required to prepare the acetabulum for the THA cup. We calculated the difference between the predicted reaming size for resurfacing and the actual reaming size to determine the effect of resurfacing on acetabular bone stock. Overall, 71%, 57%, and 41% of THAs would have had extra acetabular bone removed to implant a hip resurfacing arthroplasty cup with a line-to-line (0-mm), 1-mm, or 2-mm press fit, respectively. When compared to THA, hip resurfacing arthroplasty commonly results in additional acetabular bone resection.Clinical Orthopaedics and Related Research 08/2011; 470(2):541-6. · 2.79 Impact Factor
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ABSTRACT: Background: Conventional radiographs are routinely used to evaluate acetabular bone loss as part of the follow-up in patients who undergo total hip arthroplasty (THA). The objective of this study was to examine the accuracy and specificity of conventional radiographs reviewed by arthroplasty surgeons in detecting acetabular bone loss in patients with prior THA. Methods: Using a cadaveric pelvic model, a defined percentage of bone was incrementally removed from the posterior acetabular column, followed by implantation of uncemented cups into both acetabula. Ten orthopedic arthroplasty surgeons, blinded to the defect sizes, assessed the percentage of bone defect using standard anteroposterior, Judet and oblique conventional radiographs. Results: Observers were unable to accurately grade bone defects using conventional radiographs. For defects less than 50%, observers reported on average a defect of 11%. Although observer estimates of defects 50% or more increased, these treatmentaltering bone deficiencies remained grossly underestimated, with a sensitivity and specificity of 36.6% and 97.6%, respectively. Conclusion: Conventional radiographs reviewed by experienced arthroplasty surgeons do not reliably detect small bone lesions (< 50%). Although more successful in detecting larger bone lesions, surgeons tend to underestimate actual bone loss. Computed tomography scanning may be indicated if accurate estimation of acetabular bone loss is required in patients who have undergone previous THA.Canadian journal of surgery. Journal canadien de chirurgie 10/2012; 55(5):000511-411. · 1.63 Impact Factor