Gerard A Engh

..As documented in the literature, UKA achieves these goals. Therefore, we cannot only justify UKA as a temporizing procedure, but also as a definitive procedure with long-term results that are comparable to TKA for gonarthrosis...

..The purpose of this paper was to describe synovial entrapment and to determine if design features of the prosthesis predispose patients to the complication...

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..In this study, we tested the hypothesis that conventional polyethylene liners cross-linked by sterilization with gamma radiation in air had better in vivo wear performance than non-cross-linked liners sterilized with gas plasma...

..Our purpose was to determine the loss of thickness in polyethylene tibial inserts that were of the same design but had been sterilized differently...

..It is unclear whether one choice is superior to the other. Polyethylene quality reportedly influences the survivorship of primary TKA, but similar reports are not described for revision TKA...

..We hypothesized that polishing the baseplate surface and sterilizing the insert with means other than gamma radiation in air had reduced the prevalence of osteolysis...

..Besides illustrating deleterious consequences of using gamma-irradiated-in-air polyethylene in medial unicompartmental arthroplasty, our results support reducing varus angulation of the medial tibial plateau and knee at surgery...

..Tray depression under load application and the liftoff on the contralateral side indicated that the tibial stems limited implant rotation and that implant fixation did not deteriorate with time in situ...

..0% to 2.5%, and reoperation rates fell from 8.1% to 5.4%. These data demonstrate that despite modifications made to improve surgical technique across time, a substantial complication rate with this procedure persists...

..New locking mechanism designs directed toward better methods of securing the polyethylene insert to the tibial tray are needed to minimize the generation of particulate wear debris at the modular interface...

..000) and the burnishing score was 3 times greater for MB inserts (P = .000). At more than 5 years in situ, the linear wear measurements were similar for the 2 groups (mean penetration was 0.329 mm for MB and 0.320 mm for fixed bearing)...

..7% vs 1.0%) and the overall reoperation rate (11.3% vs 8.6%) compare unfavorably with those performed with an open technique...

..Recognition is expedited by understanding how shelf life is related to product demand and can be of aid when diagnosing the painful knee...

..4 years. This risk can be minimized by ensuring that implants have not been sterilized with gamma irradiation in air and stored for several years...

..We conclude that revision of a failed metal-backed patellar component to a cemented, all-polyethylene patella is a durable, successful procedure...

..We retrospectively reviewed our experiences with another unicondylar knee system to investigate the relationship between the shelf age of the polyethylene components and clinical outcome...

..This led to complacency toward TKA, thus inhibiting technological advances in the procedure to develop implants for younger and more active patients...

..LEVEL OF EVIDENCE: Level IV, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence...

..Therefore, modular components were examined to determine whether this innovation in TKA was actually contributing to the manifestation of osteolysis...

..Varus-valgus constrained designs cannot provide long-term stability in cases of varus-valgus instability or severe flexion laxity. Such cases are most reliably treated with a linked implant...

..We examined the clinical and radiographic outcomes of a series of revision total knee arthroplasties in which a structural allograft had been used to reconstruct a tibial bone defect encountered at the time of the revision procedure...

..Modular augments did not effectively address the bone loss and instability encountered in many instances at revision surgery. Survivorship of this implant was 79.4% +/- 13.7% at 8 years...

..The results achieved with these surgical options vary for each type of instability. In general, the use of more constrained components to manage unstable knees is favored...

..Unicondylar patients of that era who were fortunate enough to avoid a thin or aged oxidation-prone polyethylene bearing probably have enjoyed superior outcomes...

..Wear of total knee polyethylene has been quantified gravimetrically with thickness measurements and evaluation of surface wear modes. However, these techniques do not localize volumetric wear...

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..This study demonstrates the utility of ASTM F1877-98 in differentiating wear debris particles from different sources...

..See Author Guidelines for a complete description of levels of evidence...

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..Case-based discussion included total knee arthroplasty in the presence of femoral deformity, deficient patellar bone, and patella baja, and treatment of infected total knee arthroplasty...