BACKGROUND The saddle prosthesis originally was developed to reconstruct large acetabular defects in revision hip arthroplasty and was used primarily for hip reconstruction after periacetabular... Show moreBACKGROUND The saddle prosthesis originally was developed to reconstruct large acetabular defects in revision hip arthroplasty and was used primarily for hip reconstruction after periacetabular tumor resections. The long-term survival of these reconstructions is unclear. QUESTIONS/PURPOSE We therefore examined the long-term function, complications, and survival in patients treated with saddle prostheses after periacetabular tumor resection. PATIENTS AND METHODS Between 1987 and 2003 we treated 17 patients with a saddle prosthesis after periacetabular tumor resection (12 chondrosarcomas, three osteosarcomas, one malignant fibrous histiocytoma, one metastasis). During followup, 11 patients died, resulting in a median overall survival of 49 months (95% CI, 30-68 months). The remaining six patients were alive without disease (mean followup, 12.1 years; range, 8.3-16.8 years). In one patient the saddle prosthesis was removed after 3 months owing to dislocation and infection. We obtained SF-36 questionnaires, Toronto Extremity Salvage Scores (TESS), and Musculoskeletal Tumor Society (MSTS) scores. RESULTS Thirteen of 17 patients used walking assists for mobilization at last followup: eight patients required two crutches, five needed one crutch, and one did not use any walking aids. The other three patients were not able to mobilize independently and only made bed to chair transfers. The mean hip flexion in the six surviving patients was 60° (range, 40°-100°) at last followup. Local complications were seen in 14 of the 17 patients: nine wound infections, seven dislocations, and two leg-length discrepancies requiring additional surgery. In the five surviving patients with their index prosthesis still in situ, the mean MSTS score at long-term followup was 47% (range, 20%-77%), the mean TESS score was 53% (range, 41%-67%), and the mean composite SF-36 physical and mental component summaries were 43.9 and 50.6, respectively. CONCLUSION Reconstruction with saddle prostheses after periacetabular tumor surgery has a high risk of complications and poor long-term function with limited hip flexion; therefore, we no longer use the saddle prosthesis for reconstruction after periacetabular tumor resections. Show less
Hogervorst, T.; Eilander, W.; Fikkers, J.T.; Meulenbelt, I. 2012
BACKGROUND Less than 1% of all primary TKAs are performed with an all-polyethylene tibial component, although recent studies indicate all-polyethylene tibial components are equal to or better than... Show moreBACKGROUND Less than 1% of all primary TKAs are performed with an all-polyethylene tibial component, although recent studies indicate all-polyethylene tibial components are equal to or better than metal-backed ones. QUESTIONS/PURPOSES We asked whether the metal-backed tibial component was clinically superior to the all-polyethylene tibial component in primary TKAs regarding revision rates and clinical functioning, and which modifying variables affected the revision rate. METHODS We systematically reviewed the literature for clinical studies comparing all-polyethylene and metal-backed tibial components used in primary TKAs in terms of revision rates, clinical scores, and radiologic parameters including radiostereometric analysis (RSA). Meta-regression techniques were used to explore factors modifying the observed effect. Our search yielded 1557 unique references of which 26 articles were included, comprising more than 12,500 TKAs with 231 revisions for any reason. RESULTS Meta-analysis showed no differences between the all-polyethylene and metal-backed components except for higher migration of the metal-backed components. Meta-regression showed strong evidence that the all-polyethylene design has improved with time compared with the metal-backed design. CONCLUSIONS The all-polyethylene components were equivalent to metal-backed components regarding revision rates and clinical scores. The all-polyethylene components had better fixation (RSA) than the metal-backed components. The belief that metal-backed components are better than all-polyethylene ones seems to be based on studies from earlier TKAs. This might no longer be true for modern TKAs. LEVEL OF EVIDENCE Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. Show less
