Recent literature demonstrates that the main risk factors for a two-stage exchange failure are as follows: hemodialysis, obesity, multiple previous procedures, diabetes mellitus, corticosteroid therapy, hypoalbuminemia, immunosuppression, rheumatological conditions, coagulation disorders, and infection due to multidrug-resistant (MDR) bacteria or fungal species. Regarding microorganisms, besides Staphylococcus aureus, Streptococcus spp., Enterobacteriaceae species such as Klebsiella pneumoniae and Enterobacter sp., Pseudomonas aeruginosa, or Acinetobacter baumannii, and fungus including Candida sp. are also considered risk factors for a two-stage exchange failure. Resection arthroplasty, arthrodesis, and amputation have a limited role. Chronic suppression is an option for high-risk patients or unfeasible reconstruction. In summary, we report the main risk factors for a two-stage exchange failure and alternative procedures when it occurs. Future research on patient-specific risk factors for a two-stage exchange may aid surgical decision-making and optimization of outcomes.

Background and Objectives: Intraoperative fluoroscopy can be used to increase the accuracy of the acetabular component positioning during total hip arthroplasty. However, given the three-dimensional nature of cup positioning, it can be difficult to accurately assess inclination and anteversion angles based on two-dimensional imaging. The purpose of this study is to validate a novel method for calculating the 3D orientation of the acetabular cup from 2D fluoroscopic imaging. Materials and Methods: An acetabular cup was implanted into a radio-opaque pelvis model in nine positions sequentially, and the inclination and anteversion angles were collected in each position using two methods: (1) a coordinate measurement machine (CMM) was used to establish a digitalized anatomical coordinate frame based on pelvic landmarks of the cadaveric specimen, and the 3D position of the cup was then expressed with respect to the anatomical planes; (2) AP radiographic images were collected, and a mathematical formula was utilized to calculate the 3D inclination and anteversion based on the 2D images. The results of each method were compared, and interrater and intrarater reliably of the 2D method were calculated. Results: Interrater reliability was excellent, with an interclass correlation coefficient (ICC) of 0.988 (95% CI 0.975–0.994) for anteversion and 0.997 (95% CI 0.991–0.999) for inclination, as was intrarater reliability, with an ICC of 0.995 (95% CI 0.985–0.998) for anteversion and 0.998 (95% CI 0.994–0.999) for inclination. Intermethod accuracy was excellent with an ICC of 0.986 (95% CI: 0.972–0.993) for anteversion and 0.993 (95% CI: 0.989–0.995) for inclination. The Bland–Altman limit of agreement, which represents the error between the 2D and 3D methods, was found to range between 2 to 5 degrees. Conclusions: This data validates the proposed methodology to calculate 3D anteversion and inclination angles based on 2D fluoroscopic images to within five degrees. This method can be utilized to improve acetabular component placing intraoperatively and to check component placement postoperatively.

Optimal surgical management of spine trauma will restore blood flow to the ischemic spinal cord. However, spine stabilization may also further exacerbate injury by inducing ischemia. Current electrophysiological technology is not capable of detecting acute changes in spinal cord blood flow or localizing ischemia. Further, alerts are delayed and unreliable. We developed an epidural optical device capable of directly measuring and immediately detecting changes in spinal cord blood flow using diffuse correlation spectroscopy (DCS). Herein we test the hypothesis that our device can continuously monitor blood flow during spine distraction. Additionally, we demonstrate the ability of our device to monitor multiple sites along the spinal cord and axially resolve changes in spinal cord blood flow. DCS-measured blood flow in the spinal cord was monitored at up to three spatial locations (cranial to, at, and caudal to the distraction site) during surgical distraction in a sheep model. Distraction was halted at 50% of baseline blood flow at the distraction site. We were able to monitor blood flow with DCS in multiple regions of the spinal cord simultaneously at *1 Hz. The distraction site had a greater decrement in flow than sites cranial to the injury (median -40 vs. -7%,). This pilot study demonstrated high temporal resolution and the capacity to axially resolve changes in spinal cord blood flow at and remote from the site of distraction. These early results suggest that this technology may assist in the surgical management of spine trauma and in corrective surgery of the spine.

Background: Surgeons typically remain scrubbed in for the duration of a surgical case, while scrub nurses are shift-workers who handoff mid-operation. These handoffs can intuitively create inefficiencies, but currently, no orthopedic research has studied the impact of these handoffs. This study analyzed the effect of intraoperative scrub nurse handoffs on operative times for total joint arthroplasties (TJAs). Methods: A retrospective chart review was performed for primary total hip (THA) and total knee arthroplasties (TKA) performed between May 2014 and May 2018. Operative times, number of scrub nurse handoffs, surgeon, and patient information were collected. A multivariable linear regression was performed to assess the association between patient and surgeon characteristics, intraoperative handoffs, and operative times. Results: A total of 1109 TKA and 1032 THA patients were identified. Multivariable linear regression demonstrated that for TKAs, 1 handoff was associated with a 3.89-minute longer operative time (P value ¼ .02), and 2þ handoffs were associated with a 15.99-minute longer case (P value < .001). For THA patients, 1 handoff was associated with a 6.20-minute longer operative time (P value < .001), and 2þ handoffs were associated with an 18.52-minute longer case (P value < .001). Conclusions: Although causation cannot be established, when controlling for multiple confounders, intraoperative scrub nurse handoffs were associated with statistically significant increases in operative times for TJAs. Optimizing scrub nurse staffing models to decrease intraoperative handoffs could thus have practical ramifications on TJA patients.

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