X-ray micro-computed tomography in willow reveals tissue patterning of reaction wood and delay in programmed cell death.

BACKGROUND: Variation in the reaction wood (RW) response has been shown to be a principle component driving differences in lignocellulosic sugar yield from the bioenergy crop willow. The phenotypic cause(s) behind these differences in sugar yield, beyond their common elicitor, however, remain unclear. Here we use X-ray micro-computed tomography (µCT) to investigate RW-associated alterations in secondary xylem tissue patterning in three dimensions (3D). RESULTS: Major architectural alterations were successfully quantified in 3D and attributed to RW induction. Whilst the frequency of vessels was reduced in tension wood tissue (TW), the total vessel volume was significantly increased. Interestingly, a delay in programmed-cell-death (PCD) associated with TW was also clearly observed and readily quantified by µCT. CONCLUSIONS: The surprising degree to which the volume of vessels was increased illustrates the substantial xylem tissue remodelling involved in reaction wood formation. The remodelling suggests an important physiological compromise between structural and hydraulic architecture necessary for extensive alteration of biomass and helps to demonstrate the power of improving our perspective of cell and tissue architecture. The precise observation of xylem tissue development and quantification of the extent of delay in PCD provides a valuable and exciting insight into this bioenergy crop trait.

Outcome and complications following revision shoulder arthroplasty : a systematic review and meta-analysis.

AIMS: It is important to understand the rate of complications associated with the increasing burden of revision shoulder arthroplasty. Currently, this has not been well quantified. This review aims to address that deficiency with a focus on complication and reoperation rates, shoulder outcome scores, and comparison of anatomical and reverse prostheses when used in revision surgery. METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) systematic review was performed to identify clinical data for patients undergoing revision shoulder arthroplasty. Data were extracted from the literature and pooled for analysis. Complication and reoperation rates were analyzed using a meta-analysis of proportion, and continuous variables underwent comparative subgroup analysis. RESULTS: A total of 112 studies (5,379 shoulders) were eligible for inclusion, although complete clinical data was not ubiquitous. Indications for revision included component loosening 20% (601/3,041), instability 19% (577/3,041), rotator cuff failure 17% (528/3,041), and infection 16% (490/3,041). Intraoperative complication and postoperative complication and reoperation rates were 8% (230/2,915), 22% (825/3,843), and 13% (584/3,843) respectively. Intraoperative and postoperative complications included iatrogenic humeral fractures (91/230, 40%) and instability (215/825, 26%). Revision to reverse total shoulder arthroplasty (TSA), rather than revision to anatomical TSA from any index prosthesis, resulted in lower complication rates and superior Constant scores, although there was no difference in American Shoulder and Elbow Surgeons scores. CONCLUSION: Satisfactory improvement in patient-reported outcome measures are reported following revision shoulder arthroplasty; however, revision surgery is associated with high complication rates and better outcomes may be evident following revision to reverse TSA. Cite this article: Bone Jt Open 2021;2(8):618-630.

An independent learning method for orthopaedic surgeons performing shoulder ultrasound to identify full-thickness tears of the rotator cuff.

BACKGROUND: There is an evolving interest in shoulder ultrasound performed by orthopaedic surgeons as part of routine clinical assessment of the rotator cuff in a so-called one-stop clinic. This study investigated the accuracy of ultrasound assessment of rotator cuff integrity performed by orthopaedic surgeons without prior experience of ultrasound who were following our proposed learning protocol. METHODS: We studied four surgeons without previous experience with shoulder ultrasound and monitored their ability to evaluate rotator cuff integrity using ultrasound compared with findings at arthroscopy. The surgeons attended a formal training course and were taught a protocol to identify and size full-thickness tears of the rotator cuff. The surgeons performed preoperative scans on the day that patients underwent shoulder arthroscopy. This allowed the surgeons to receive same-day feedback with comparison of arthroscopic images and ultrasound images. RESULTS: One hundred and fifty-nine shoulders were scanned by the surgeons in the study. In the initial training period, surgeons who performed >100 scans demonstrated a sensitivity of 94% and a specificity of 88% (a positive predictive value of 79% and a negative predictive value of 97%) for the identification of a full-thickness tear and agreed with intraoperative sizing of the defect in 84% of the scans. In the later training period, the predictive values showed a sensitivity of 90% and a specificity of 97% (a positive predictive value of 95% and a negative predictive value of 94%) for the identification of a full-thickness tear and agreement with intraoperative sizing for 95% of the scans. CONCLUSIONS: The predictive values obtained in this study for the evaluation of rotator cuff integrity were comparable with published results from experienced radiologists. This study demonstrates the capacity of our proposed learning protocol to train surgeons without previous ultrasound experience to reliably evaluate rotator cuff integrity using ultrasound within fifty to 100 scans.