Background: Jones fractures of the proximal fifth metatarsal are predisposed to delayed union and nonunion due to a tenuous blood supply. Solid intramedullary (IM) screw fixation is recommended to improve healing, traditionally followed by delayed weightbearing (DWB). However, early weightbearing (EWB) postoperatively may facilitate functional recovery. The purpose of this study was to compare union rates and time to union after solid IM screw fixation of Jones fractures in patients treated with an EWB protocol to those treated with a DWB protocol, as well as to identify any factors that may be predictive of delayed or nonunion. Methods: True Jones (zone 2 fifth metatarsal base) fractures treated from April 2012 through January 2018 with IM screw fixation and 6 months follow-up were identified (41 fractures in 40 patients; mean ± SD age, 45.3 ± 17.9 years). Patients were divided into EWB and DWB cohorts (within or beyond 2 weeks, respectively). Delayed union (12.5 weeks) was statistically derived from established literature. Union times were compared between cohorts. Regression analyses were conducted to investigate possible confounders contributing to delayed union. There were 20 fractures in the EWB cohort and 21 fractures in the DWB cohort. Results: There was no significant difference in healing times (EWB: 25% by 6th week, 55% by the 12th week, 20% delayed; DWB: 33% by 6th week, 43% by 12th week, 24% delayed; P = .819) or delayed unions (EWB, 20% vs DWB, 24%; P > .999). There were no nonunions. No significant confounding risk factors were identified. Conclusion: Postoperative protocols using early weightbearing following solid IM screw fixation of Jones fractures appear to be safe and do not delay fracture healing or increase the risk of delayed union. Older age may be a risk for delayed union, but larger studies are needed to evaluate this with appropriate power in light of possible confounders. EWB protocols may allow better functional recovery without compromising outcomes by increasing the risk of delayed union. Level of Evidence: Therapeutic level III, retrospective comparative study.
Introduction We hypothesize that respiratory variation in the pulmonary artery tracing predicts fluid responsiveness (primary hypothesis) and that inclusion of multiple physiologic waveforms as well as ventilator settings in a predictive model of fluid responsiveness would lead to improvements in the clinical utility of this class of metrics (secondary hypothesis). Methods Blood pressure tracings were prospectively recorded in 35 patients immediately following cardiac surgery. Fluid bolus administration data, ventilator settings, and cardiac output were recorded prospectively before and after fluid boluses given at the discretion of the treating physician. Results We observed statistically significant but limited relationships between pulmonic (r(2) = .26, P = .0052) and systemic (r(2) = .13, P = .011) pulse pressure variation and changes in cardiac index. A multiparameter estimate of fluid responsiveness, which included respiratory variation in central venous pressure and pulmonary artery pressure, indexed tidal volumes, positive end-expiratory pressure, and mean airway pressure, was also correlated with change in cardiac index (r(2) = .42, P = .0056). Using the area under the curve (AUC) technique to compare specificity and sensitivity, dynamic indicators (AUC = 0.74, 0.67, and 0.81 for systemic arterial respiratory [pulse pressure] variation, pulmonic arterial respiratory [pulse pressure] variation, and the multiparameter estimate, respectively) outperformed static estimates (0.49 and 0.48 for central venous pressure and pulmonary artery diastolic pressure, respectively). Conclusion While integration of multiple physiologic waveforms as well as ventilator parameters improves the predictability of fluid responsive metrics in the setting of lung-protective ventilation, the composite index may still be of limited predictive value.
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