Early failures of metal-on-metal total hip arthroplasty (THA) occur due to aseptic loosening, metal hypersensitivity reactions, pseudotumor formation, and component seizing. The purpose of this study was to investigate the timing, common modes of failure, clinical outcomes, and incidence of metal-on-metal THA revisions. A review was performed of 80 patients who underwent revision of a failed metal-on-metal THA for any reason. The most common reason for metal-on-metal failure was aseptic acetabular loosening, with a rate of 56.25% (45/80 patients). Early failure of metal-on-metal THAs was noted, with 78% of these revisions being performed within 2 years of the index operation and 92.5% within 3 years. Furthermore, 13% of patients experienced significant localized soft tissue reactions. Mean preoperative Harris Hip Score was 42.35 ± 14.24 and mean postoperative Harris Hip Score was 66.5 ± 23.2 (range, 9.55-95.4), with an average follow-up of 438 ± 492 days (range, 40-2141), or 1.2 years.It is imperative that clinicians be cognizant of the fact that the proposed advantages of metal-on-metal THA are not without potential detrimental sequelae. This article proposes an algorithm to aid in diagnosing the etiology of a painful metal-on-metal THA, as well as 2 classification schemes regarding metal-on-metal THA complications to help direct treatment.

No abstract

Primary care must be reengineered to improve outcomes and affordability. To achieve those goals, WellPoint invested in ten patientcentered medical home pilots that encourage care coordination, preventive care, and shared decision making. Two of the three pilots described in this article-in Colorado and New Hampshire-layer incentive payments for care coordination and quality improvement on top of a traditional fee-for-service payment. The third-in New York-pays doctors an enhanced fee that is tied to achievement of quality levels. Preliminary evaluations show encouraging signs that the Colorado and New Hampshire pilots are meeting some cost, utilization, and quality objectives. A full evaluation in all three states is ongoing. To help enable systemwide transformation, WellPoint is now applying similar payment strategies to primary care practices that may not have the resources to become full-fledged medical homes.

Planning for surgical correction of lower-limb deformity requires assessment of the character and extent of the deformity. Deformity measurements are defined; however, the reliability of these measurements has not been evaluated. This study was conducted to assess the interobserver and intraobserver reliability of lower extremity deformity measurements in the frontal and sagittal planes. Anteroposterior and lateral lower extremity radiographs were evaluated using Paley technique. Statistical analysis included intraclass correlation coefficient (2,1), median absolute difference, range, and agreement within 3 and 5 degrees. Reliability was good to very good for all measurements except for the anterior distal tibial angle, which had moderate reliability. Intraobserver reliability was higher than interobserver reliability, and measurements in the frontal plane had better reliability than measurements in the sagittal plane. Overall, these measurements are a reliable method of assessing lower extremity deformity and should be used to guide treatment and monitor outcome.

Background Implantation of an antibiotic bone cement spacer is used to treat infection of a TKA. Dynamic spacers fashioned with cement-on-cement articulating surfaces potentially facilitate patient mobility and reduce bone loss as compared with their static counterparts, while consisting of a biomaterial not traditionally used for load-bearing articulations. However, their direct impact on patient mobility and wear damage while implanted remains poorly understood. Questions/purposes We characterized patient activity, surface damage, and porous structure of dynamic cementon-cement spacers. Methods We collected 22 dynamic and 14 static knee antibiotic cement spacers at revision surgeries at times ranging from 0.5 to 13 months from implantation. For these patients, we obtained demographic data and UCLA activity levels. We characterized surface damage using the Hood damage scoring method and used micro-CT analysis to observe the internal structure, cracking, and porosity of the cement. Results The average UCLA score was higher for patients with dynamic spacers than for patients with static spacers, with no differences in BMI or age. Burnishing was the only prevalent damage mode on all the bearing surfaces. Micro-CT analysis revealed the internal structure of the spacers was porous and highly inhomogeneous, including heterogeneous dispersion of radiopaque material and cavity defects. The average porosity was 8% (range, 1%-29%) and more than 1 . 2 of the spacers had pores greater than 1 mm in diameter. Conclusions Our observations suggest dynamic, cementon-cement spacers allow for increased patient activity without catastrophic failure. Despite the antibiotic loading and internal structural inhomogeneity, burnishing was the only prevalent damage mode that could be consistently classified with no evidence of fracture or delamination. The porous structure of the spacers varied highly across the surfaces without influencing the material failure.

No abstract

No abstract

No abstract