SUMMARYThis paper highlights the potential of integrating SHM concepts into an external fixator with the aim of using it to assess the healing of a fractured femur. A finite element analysis was first performed on the fixated femur to understand the response of the fixated femur in its fractured and healed state. The underlying mechanics will be used to establish a suitable monitoring strategy for assessment of healing. The results will be supported by a series of experiments using a fixated saw-bone femur, which has been cut to simulate fracture. The cut was filled with epoxy, and the curing of this epoxy was used to simulate healing of the fractured region. The findings lead to an actuation and sensing protocol able to determine the state of union of a fixated long bone. This methodology was tested further by using modelling clay to approximate the mass added by soft tissue surrounding the bone. These results illustrate that the integration of SHM and orthopaedic concepts can provide a quantitative measure that can be used in conjunction with existing techniques for the monitoring of the state of healing of the fracture. This represents a significant potential of reducing or eliminating the qualitative healing assessment.

A B S T R A C T A series of experimental investigations are performed to show the potential of integrating sensing elements into an external fixation for healing assessment of a fracture femur. This investigation is supported by finite element analyses that highlight the fundamental structural dynamics, which enable a stiffness-based healing assessment methodology. A saw-bone femur externally fixated with a Hoffman II will be subjected to an artificial fracture. The healing of the fractured femur is simulated with the curing of epoxy applied to the fractured region. The finite element analyses results will help determine the useful modes for assessing the state of healing of the fracture that can be attributed to the changes in the stiffness of the fixated structure. The findings will be tested against a set of experiments to show how the stiffness-related quantities can be delineated from the dynamic response. The results reported will show distinct changes to the frequency response functions as the epoxy cures demonstrating the potential of integrating sensors onto an external fixation for healing and fracture union assessment.Keywords bone fracture; bone healing assessment; structural health monitoring. N O M E N C L A T U R E(x,y,z) = Cartesian coordinate system ρ = density E = Young's modulus ν = Poisson's ratio f = frequency Z tf ( f ) = transfer function v force (t) = voltage time series from force transducer attached to impactor (load cell) v PVDF (t) = voltage time series from polyvinylidene fluoride sensor (film sensor) vˆf orce f ð Þ = voltage amplitude in frequency domain from force transducer attached to impactor vˆP VDF f ð Þ = voltage amplitude in frequency domain from polyvinylidene fluoride sensor ε(t) = strain time series ε s (f) = strain spectrum i(t) = input force time series Iˆf ð Þ = input force spectrum K force = force constant K PVDF = strain constant

Purpose: To compare serum vitamin D levels and patterns of ultraviolet light and dietary exposure among patients with active and inactive noninfectious uveitis and population controls. Design: Prospective case-control study. All participants (n ¼ 151) underwent serum 25-hydroxy vitamin D measurement and completed a questionnaire on vitamin D intake and ultraviolet light exposure. Serum 25-hydroxy vitamin D levels were compared between active and inactive uveitis groups and with local population estimates. Participants: Adult patients with active and inactive noninfectious uveitis were recruited from 2 Victorian tertiary hospitals and 1 private ophthalmic practice. Methods: Serum 25-hydroxy vitamin D levels were compared between patients with active and inactive uveitis and population-based estimates of serum 25-hydroxy vitamin D levels, stratified by geographic region and season. Vitamin D intakes and exposures based on questionnaire results, including vitamin D supplementation and sunlight exposures on weekdays and weekends, were compared between active and inactive uveitis groups. Main Outcome Measures: Serum vitamin D levels, intake of vitamin D, and exposure to sources of vitamin D. Results: The median level of serum vitamin D in those with active uveitis (n ¼ 74) was 46 nmol/l (interquartile range [IQR], 29e70 nmol/l), significantly lower than in the inactive control group (n ¼ 77) at 64 nmol/l (IQR, 52e79 nmol/l; P < 0.001). The active uveitis group also showed lower median serum vitamin D levels than the local population median of 62 nmol/l (IQR, 46e77 nmol/l). Vitamin D supplementation also was associated significantly with uveitis inactivity (P ¼ 0.026, Kendall's s test). In a subanalysis of vitamin Dedeficient participants, sun exposure was associated significantly with uveitis inactivity (P ¼ 0.014 for weekday and weekend analyses). Conclusions: Participants with active uveitis showed significantly lower serum 25-hydroxy vitamin D levels than inactive uveitis patients and local population-based estimates. Vitamin D supplementation was found to be associated with decreased uveitis activity, as was sun exposure in those with vitamin D deficiency. These results suggest that vitamin D supplementation should be studied as an option for the prevention of uveitis relapse in at-risk patients. Ophthalmology 2020;127:230-237 ª 2019 by the American Academy of Ophthalmology Supplemental material available at www.aaojournal.org. See Commentary on page 238. Uveitis, defined as intraocular inflammation, is the fifth leading cause of vision loss in the United States, causing 10% to 15% of visual impairment in the Western world. 1 Because it commonly affects young people, uveitis has a profound impact on quality-adjusted life-years and a disproportionately high socioeconomic burden. 2 Noninfectious, immunemediated uveitis is the most common form of uveitis in developed countries. 3 Clinically, uveitis can be classified as active or inactive. Recurrent and chronic uveitis are the most problematic and are associated with...

Purpose Four cases of ibrutinib-related uveitis are presented, which are to the best of our knowledge the first in the literature. Possible mechanisms of ibrutinib-mediated uveitis are explored. Observations Case 1 is a 60-year-old female who had been stable on 1 year of ibrutinib for chronic lymphocytic leukaemia. She was diagnosed with ibrutinib-related uveitis, which responded well to topical steroids. Case 2 is a 63-year-old male diagnosed with uveitis after 2 years of ibrutinib treatment for chronic lymphocytic leukaemia. He responded well to topical and oral steroids; however, he continued to have uveitis relapses after weaning steroids. Case 3 is a 69-year-old male diagnosed with uveitis after 18 months of ibrutinib treatment. He was trialed on topical and intravenous steroids, and restarted ibrutinib without worsening of symptoms. Case 4 is a 66-year-old female who developed uveitis after being stable on ibrutinib for 3 years. She responded well to topical steroids. Conclusions and Importance Inflammatory complications of tyrosine kinase inhibitors are well described. While ibrutinib, and other kinase inhibitors, are generally well-tolerated, there are increasing reports of ocular toxicities, including uveitis. It is recommended to monitor patients for potential ocular adverse effects and facilitate rapid ophthalmologic assessment.