An enhanced protocol to reduce error in electromagnetic tracking of first metatarsophalangeal joint motions

Background: Error associated with markers or sensors surface-mounted onto skin reduces the validity of kinematic models. Extensor tendon excursion at the first metatarsophalangeal joint (MTPJ) has been noted previously to be especially problematic. An enhanced skin mounting protocol is described and validated. Methods: A Fastrak� system was used to obtain kinematic data concurrently from two pairs of sensors mounted on either side of the first MTPJ of nine freshly frozen cadaveric feet. One sensor pair was mounted directly into the medulla of each of the first metatarsal and proximal phalanx of the hallux, with the second pair attached to the skin over the same segments, using each of two mounting protocols. A standard mounting protocol was compared to a new enhanced protocol that secured the sensor on the hallux with a stabilizing cuff. Results: The addition of a stabilizing cuff on the hallux sensor reduced root mean square error in first MTPJα rotations by 1.45°during passive rotation and 1.61°during active rotation compared with the standard protocol (P = 0.008 and 0.028, respectively). The cuff protocol improved CMC reliability coefficients for α rotations from 0.918 to 0.973 for passive MTPJ motion, and from 0.922 to 0.973 for active motion. Conclusion: Securing the hallux mounted sensor with a stabilizing cuff reduced error by more than one-third without reducing first MTPJ total range of motion. © 2005 Elsevier B.V. All rights reserved

Body mass index and complications following major gastrointestinal surgery: A prospective, international cohort study and meta-analysis

Aim Previous studies reported conflicting evidence on the effects of obesity on outcomes after gastrointestinal surgery. The aims of this study were to explore the relationship of obesity with major postoperative complications in an international cohort and to present a metaanalysis of all available prospective data. Methods This prospective, multicentre study included adults undergoing both elective and emergency gastrointestinal resection, reversal of stoma or formation of stoma. The primary end-point was 30-day major complications (Clavien–Dindo Grades III–V). A systematic search was undertaken for studies assessing the relationship between obesity and major complications after gastrointestinal surgery. Individual patient meta-analysis was used to analyse pooled results. Results This study included 2519 patients across 127 centres, of whom 560 (22.2%) were obese. Unadjusted major complication rates were lower in obese vs normal weight patients (13.0% vs 16.2%, respectively), but this did not reach statistical significance (P = 0.863) on multivariate analysis for patients having surgery for either malignant or benign conditions. Individual patient meta-analysis demonstrated that obese patients undergoing surgery formalignancy were at increased risk of major complications (OR 2.10, 95% CI 1.49–2.96, P < 0.001), whereas obese patients undergoing surgery for benign indications were at decreased risk (OR 0.59, 95% CI 0.46–0.75, P < 0.001) compared to normal weight patients. Conclusions In our international data, obesity was not found to be associated with major complications following gastrointestinal surgery. Meta-analysis of available prospective data made a novel finding of obesity being associated with different outcomes depending on whether patients were undergoing surgery for benign or malignant disease