Breast Tissue Expander With Radiofrequency Identification Port: Assessment of MRI Issues.

OBJECTIVE. Breast tissue expanders with magnetic ports are MRI unsafe, preventing patients from benefiting from the diagnostic capabilities of MRI. A tissue expander was recently developed with a radiofrequency identification (RFID) port used for needle location and expansion that may be acceptable for a patient undergoing MRI. The purpose of this investigation was to evaluate MRI issues using standardized techniques and well-accepted methods for this tissue expander with RFID port. MATERIALS AND METHODS. The breast tissue expander with RFID port (Motiva Flora Tissue Expander, Establishment Labs) was assessed for magnetic field interactions (translational attraction and torque, 3 T), MRI-related heating (1.5 T/64 MHz and 3 T/128 MHz), artifacts (3 T), and functional changes associated with different MRI conditions (1.5 T/64 MHz and 3 T/128 MHz). RESULTS. Magnetic field interactions were minor (deflection angle of 2° and no torque) and thus will not pose a risk. At 1.5 T/64 MHz and 3 T/128 MHz, the highest temperature elevations (1.7°C and 1.9°C, respectively) were physiologically inconsequential. The tissue expander with RFID port exhibited relatively small artifacts on MRI. Exposures of the tissue expander with RFID port to different MRI conditions did not impact the ability to localize the RFID port or to read the electronic serial number. CONCLUSION. The findings indicated that this tissue expander with RFID port is "MR Conditional" for a patient referred for MRI at 1.5 T or 3 T. Importantly, the relatively small artifact associated with this implant offers potential advantages for patients undergoing MRI compared with tissue expanders that have magnetic ports that create substantial signal losses and distortions on MR images.

Cost-effectiveness model comparing dual-mobility to fixed-bearing designs for total hip replacement in France.

BACKGROUND: Instability is among the main causes of total hip arthroplasty (THA) failure. In clinical studies, THA with a dual-mobility cup (THA-DM) decreased the risk of instability after primary THA compared to THA with a fixed-bearing design (THA-FB). However, whether THA-DM is more cost-effective than THA-FB has not been established using Markov modelling with determination of the incremental cost-effectiveness ratio (ICER). The objectives of this work were to: (1) measure the efficiency of these two options, (2) use the nationwide hospital electronic database (PMSI) to estimate direct costs of dislocations and revisions for instability, and (3) conduct deterministic and probabilistic sensitivity analyses to estimate potential mean annual cost-savings in France. HYPOTHESIS: We hypothesised that primary THA-DM was cost-saving compared to primary THA-FB. MATERIAL AND METHODS: In the database, we identified 80,405 patients who had THA in 2009 and we collected their outcomes over 4 years (2009-2012). Cost-effectiveness was assessed based on the costs of resources used for all consequences of prosthetic dislocation and paid for by the statutory health insurance system or other sources. RESULTS: THA-DM was associated with a relative risk of dislocation of 0.4 versus THA-FB. This risk difference translated into 3283 fewer dislocations per 100,000 patients with THA-DM. The corresponding cost-savings for the 140,000 primary THA procedures done in France annually was 39.62 million Euros. A relative risk of 0.2 would yield annual cost-savings of 56.28 million Euros. In the probabilistic sensitivity analysis, THA-DM was the less costly option under all hypotheses, with potential maximum cost-savings of more than 100 million Euros per year in France. DISCUSSION: This comparative cost-effectiveness analysis suggests that THA-DM may induce substantial cost-savings compared to THA-FB. This possibility should be assessed by long-term clinical studies of new-generation DM prostheses.

Incidence and management of hip dislocation in tumour patients with a modular prosthesis of the proximal femur.

PURPOSE: Little data is available about the incidence and especially the management of hip dislocation following the implantation of modular tumor prostheses of the proximal femur. In this retrospective single-centre study we assessed the incidence of hip dislocation following implantation of a proximal femoral modular prosthesis as well as the success of the subsequent surgical or non-surgical treatment in tumor patients. METHODS: Between 1982 and 2008, 166 tumor patients received a modular prosthesis of the proximal femur at our institution. The average age at the time of surgery was 50 ± 20 years (range, six to 84 years). An additional pelvic reconstruction was done in 14 patients. An artificial band for soft tissue reconstruction of the hip was used in 19 patients. The average time of follow-up was 46 ± 64 months (range, one to 277 months). RESULTS: The overall dislocation rate after proximal femoral replacement was 13% after a mean time of seven ± eight months (range, 0.3-33 months) after surgery. Between 1982 and 1986 the dislocation rate was 33% and declined to 9% in subsequent years (1987-2008). Patients who had received an additional pelvic reconstruction had a three fold higher dislocation rate (p <0.05). Patients with closed reduction had a 58% (eight of 12) re-dislocation rate compared to 11% (one of nine) for open reduction (p = 0.0357). CONCLUSIONS: Dislocation of a modular prosthesis of the proximal femur is a common complication, especially in cases with additional pelvic resection with extensive bone and soft-tissue defects. Open surgical management may be more effective in preventing re-dislocation than closed reduction and bracing alone.

Assessment of reactive synovitis in rotating-platform posterior-stabilized design: a 10-year prospective matched-pair MRI study.

This is the first long-term (mean 11.6 years), prospective, matched-pair study (based on age, gender, BMI and UCLA scores) using MAVRIC (multi-acquisition variable-resonance image combination) magnetic resonance imaging to analyze reactive synovitis and osteolysis between rotating-platform posterior-stabilized (RP-PS), fixed-bearing metal-back (FB-MB), and all-polyethylene tibial (APT) in active patients (24 total, 8 in each group, mean age of 64 years, mean UCLA of 8.5) with identical femoral component and polyethylene. Reactive synovitis was observed in 6 RP-PS (75%), all 8 FB-MB (100%), and 6 APT (75%). There was a significant difference between the RP-PS and FB-MB knees in volumetric synovitis (P=0.023). Osteolysis with bone loss more than 4mm was seen in 3 FB-MB, 2 APT and none for RP-PS. These were not statistically significant.

Comparative effectiveness of metal-on-metal and metal-on-polyethylene bearings in Medicare total hip arthroplasty patients.

The purpose of this study was to compare the risk of complication and revision total hip arthroplasty (THA) in Medicare THA patients with different bearings. Using the 100% Medicare database (2005-2009), the adjusted risk of complication and revision THA was calculated for 148,827 THA patients (93,929 metal-on-polyethylene, 49,646 metal-on-metal, 5252 ceramic-on ceramic). Adjusted risk of deep vein thrombosis, dislocation, periprosthetic joint infection (PJI), mechanical loosening, periprosthetic fracture, and revision THA at up to 4 years postoperatively was compared using Cox regression. After adjusting for patient and hospital factors, metal-on-metal bearings were associated with higher risk of PJI (P = .001), mechanical loosening (P < .001), and deep vein thrombosis (P = .031) than metal-on-polyethylene bearings and higher risk of PJI (P = .014) than ceramic-on-ceramic bearings. Overall short-term revision rates did not vary significantly across bearing types, consistent with registry data. The benefits of hard-on-hard bearings in Medicare patients remain unproven, and further study is needed to compare long-term complication and revision rates in Medicare THA patients with different bearing types.

Colonic stents: the modern treatment of colonic obstruction.

Colonic stents traditionally have been used for the management of colorectal cancer, either as a palliative treatment or as a bridge to surgery. More recently, colonic stents have also been advocated as part of the therapy of benign strictures. A number of colonic stents are available worldwide, four of which are made in the USA. These stents are classified as covered or uncovered, with similar clinical applications. Technical and clinical success rates are similar among these different stents, as well as the rate of complications, which mainly consist of obstruction and migration. The deployment systems utilize fluoroscopy, endoscopy, or both. More recently, stents became available that are deployed "through the scope" (TTS) making the procedure faster. However, this advance does not exclude the use of fluoroscopy, particularly in those cases where the direct visualization of the proximal end of the stricture is absent. The increasing experience in the management of colorectal cancer with colonic stents decreases the morbidity and mortality, as well as cost, in comparison with surgical intervention for acute colonic obstruction. Management with colonic stents can also rule out proximal synchronous lesions after initial decompression prior to definitive surgery. Benign conditions may also be treated with stents. A multidisciplinary approach for the use of colonic stents during assessment and management of acute colonic obstruction is necessary in order to achieve a satisfactory outcome, whether that be better quality of life or improved survival.