Sequentially annealed highly crosslinked polyethylenes (HXLPEs) were introduced in total knee replacement (TKR) starting in 2005 to reduce wear and particle-induced osteolysis. Few studies have reported on the clinical performance of HXLPE knees. In this study, we hypothesized that due to the reduced free radicals, sequentially annealed HXLPE would have lower oxidation levels than gamma inert-sterilized controls. 145 tibial components were retrieved at consecutive revision surgeries at 7 different surgical centers. 74 components were identified as sequentially annealed HXLPE (X3, Stryker) while the remainder (n = 71) were conventional gamma inert sterilized polyethylene. The sterilization method was confirmed by tracing the lot numbers by the manufacturer. The conventional inserts were implanted for 1.7 years (Range: 0.0–9.3 years), while the X3 components were implanted 1.1 years (Range: 0.0–4.5 years). Surface damage was assessed using the Hood method. Oxidation analysis was performed in accordance with ASTM 2102 following submersion in boiling heptane for 6 hours to remove absorbed lipids. 30 of the conventional and 29 of the HXLPE inserts were available for oxidation analysis.Introduction
Methods
The purpose of this multicenter study was to assess the oxidative stability, mechanical behavior, wear and reasons for revision of 2nd generation sequentially annealed HXLPE, X3, and compare it to 1st generation XLPE, Crossfire. We hypothesized that X3 would exhibit similar wear rates but lower oxidation than Crossfire. 182 hip liners were consecutively retrieved during revision surgeries at 7 surgical centers and continuously analyzed over the past 12 years in a prospective, multicenter study. 90 were highly crosslinked and annealed (Crossfire; Implanted 4.2±3.4 years, max: 11 years), and 92 were highly crosslinked and annealed in 3 sequential steps (X3; Implanted 1.2±1.5 years; max: 5 years). Oxidation was characterized in accordance with ASTM 2102 using transmission FTIR performed on thin sections (∼200μm) from the superior/inferior axis. Mechanical behavior was assessed via the small punch test (ASTM 2183).Introduction
Methods
The aim of the study was to assess the validity of the new device [BREVIO] [AEND] [Level 2 evidence] in diagnosing carpal tunnel syndrome in the outpatient setting when used by personnel not trained previously in neurophysiologic methods. We prospectively compared the results from a portable handheld automated electroneurodiagnostic devices (AEND) the BREVIO with those from conventional nerve conduction studies. We calculated specificity and sensitivity. We also studied the limits of agreement and correlation between measured latencies. Patient satisfaction with new device was recorded. Twenty-seven participants (42 hands) were tested. The average age was 56.43 years (38-79). There were 16 females and 11 males. The sensitivity and specificity of the BREVIO as compared to conventional methods were 80% and 75% using distal motor latencies; using distal sensory latencies the sensitivity and specificity were 90% and 60% respectively. The limits of agreement between the sensory and motor latencies using Bland Altman plots were good. Similarly there was good correlation between values measured with the Pearson's correlation coefficient. The position of the baseline cursor was questionable in 19 hands. Repositioning the cursor reduced the number of false positive results which would increase the specificity of the device. The average pain score, VAS on a scale of 1-10, with the BREVIO was 1.69 (1-4) and 3.11(1-5) with conventional testing. The average satisfaction rating on a scale of 1-5 was 1.39 with the BREVIO and 2.73 with the conventional nerve conduction testing. The BREVIO is an interesting device. We recommend its use by untrained persons only under the supervision of someone trained in neurophysiology who is aware of potential pitfalls.
