Background Stemless reverse total shoulder arthroplasty (rTSA) is one of the many modifications of the original Grammont rTSA design. Much has been made of the debate between stemless and stemmed humeral implants for anatomic reverse shoulder arthroplasty (RSA), with less attention awarded to the relatively newer variation in stemless rTSA. Proposed advantages of said design include preserving bone stock, ease of revision, reduced blood loss and shortening surgical times. Methods A systematic search was conducted in accordance with PRISMA guidelines using search engines in PubMed, EMBASE and Cochrane to retrieve all relevant studies. Results Initial search strategies produced 174 studies, of which 15 studies were included for full analysis in this review. This included 657 shoulders in 648 patients (9 bilateral cases). Stemless rTSA lead to significant improvement in functional outcomes and range of movement (ROM) across all studies. Meta-analysis of comparative studies including stemless and stemmed rTSA showed no significant difference in ROM measurements across abduction (Standardized Mean Difference (SMD) -0.17, 95% CI: -1.05, 0.70) or forward flexion (SMD -0.36, 95% CI: -1.23, 0.50). However, there was a statistically significant difference in internal rotation in favor of stemless implants (SMD -0.79, 95% CI: -1.56, -0.03). There was no significant difference in visual analogue score (VAS) between stemmed and stemless designs (SMD -0.31, 95% CI: -2.32, 1.69). Likewise, there was no significant difference in odds ratio (OR) for revision rates (OR 1.02, 95% CI: 0.92, 1.14) or overall complications (OR 0.82, 95% CI: 0.2, 3.42) Across all 15 studies, comparative and non-comparative studies, overall complication rates for stemless rTSA stood at 13.4% and revision rates at 5.5%. Conclusion Stemless rTSA achieves similar functional outcomes to stemmed rTSA designs. Stemless designs achieved superior internal rotation in the comparative studies. Proposed advantages of stemless rTSA including reduced blood loss and lesser surgical times need further research, as does the long-term robustness of this relatively novel design.

Introduction: This study aimed to evaluate infection-free survival and outcomes after two-stage revision surgery for hip periprosthetic joint infection (PJI) performed in a specialised arthroplasty unit over 20 years. Methods: We retrospectively identified 158 hips (154 patients) treated with two-stage revision surgery for hip PJI between 2001 and 2021. We analysed their data and presented their infection-free survival, re-operation rate, mortality, risk factors and complications. Results: The mean follow-up time was 9 (2 to 21.7) years. A total of 22 hips (13.9 %) were re-infected. The infection-free survival was 94.4 % at 2 years, 89.3 % at 5 years, 84.2 % at 10 years, and 82.6 % at 15 and 20 years. The re-operation rate for aseptic causes was 12 %, and the most common cause of re-operation was dislocation (7 %). The cumulative survival for re-operation for aseptic causes was 93.6 % at 2 years, 89.7 % at 5 years, 88.8 % at 10 years, and 82.8 % at 15 and 20 years. The cumulative survival for all-cause re-revision was 88.8 % at 2 years, 80.8 % at 5 years, 74.9 % at 10 years, and 68 % at 15 and 20 years. The mean Western Ontario and McMaster Universities Arthritis Index (WOMAC) hip score significantly improved from 68.3 at the pre-operative stage to 35.9 at 2.1 (2 to 3.3) years, 35.3 at 5.3 (5 to 8.4) years, 38.3 at 11.3 (10–15) years and 43.8 at 18.7 (16.5 to 21.7) years (p<0.01). Duration of antibiotics and gram-negative infection were the only predictive risk factors for re-infection. Conclusion: Our results of the two-stage revision protocol for hip PJI were satisfactory and comparable with the best reported outcomes.

Study Design. Observational serial CT analysis of the lumbar spine in a normal-aging population. Objective. Assess the natural history of IntraDiscal Vacuum Phenomenon and its role in disc degeneration. Summary of Background Data: The natural history of disc degeneration is well described but our understanding of the end stage of pathogenesis remains incomplete. MRI loses accuracy with advanced degeneration, becoming hyporesonant and indistinct. Cadaveric specimens display adaptive changes in the disc with loss of the hydrostatic capacity of the nucleus, increased intra-discal clefts and end-plate impermeability. IDVP is associated with advanced disc degeneration and CT is the optimal modality to visualise this, yet these insights remain unreported. Methods. Subjects only included historic CT abdomen scans of those over 60 years of age without acute or relevant spinal pathology, with a diagnosis of at least one level with IDVP on the original CT scan and all of whom had a similar scan >7 years later. A history of clinically significant back pain was also recorded. Results. CT scans included 360 levels in 29 males and 31 females (mean 68.9 years), displaying 82 levels of IDVP, with a second scan included after a mean of 10.3 years, Most levels displayed the same level of severity (persisted, 45) compared to where some progressed (26), regressed (8) and fused (3) ( P <0.01). There was also an increased incidence, 37/60 (62%) of developing IDVP at another level. Disc heights were reduced with increased severity of IDVP. A record of back pain was evident in 31/60 subjects, which was not significantly worse in those with worsening severity or additional level involvement over the study period. Conclusion. As disc degeneration advances, the associated IDVP persists in most cases, displaying a plateauing of severity over long periods, but rarely with progression to autofusion.

Aditya Billur, Conor McNamee, Benjamin M. Mac Curtain, Neil Wu, Jake M. McDonnell, Julia Wall, Stacey Darwish, Joseph S. Butler

This paper presents a comprehensive overview of the environmental impact of surgical procedures and highlights potential strategies to reduce the associated greenhouse gas emissions. We discuss procurement, waste management, and energy consumption, providing examples of successful interventions in each area. We also emphasize the importance of adopting the Green Theatre Checklist as a useful tool for clinicians aiming to implement sustainable surgical practices.

BACKGROUND CONTEXT:Various statistical approaches exist to delineate learning curves in spine surgery. Techniques range from dividing cases into intervals for metric comparison, to employing regression and cumulative summation (CUSUM) analyses. However, their inherent inconsistencies and methodological flaws limit their comparability and reliability. PURPOSE:To critically evaluate the methodologies used in existing literature for studying learning curves in spine surgery and to provide recommendations for future research. STUDY DESIGN:Systematic literature review. METHODS:A comprehensive literature search was conducted using PubMed, Embase, and Scopus databases, covering articles from January 2010 to September 2023. For inclusion, articles had to evaluate the change in a metric of performance during human spine surgery across time/a case series. Results had to be reported in sufficient detail to allow for evaluation of individual performance rather than group/institutional performance. Articles were excluded if they included cadaveric/nonhuman subjects, aggregated performance data or no way to infer change across a number of cases. Risk of bias was assessed using the Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) tool. Surgical data were simulated using Python 3 and then examined via multiple commonly used analytic approaches including division into consecutive intervals, regression and CUSUM techniques. Results were qualitatively assessed to determine the effectiveness and limitations of each approach in depicting a learning curve. RESULTS:About 113 studies met inclusion criteria. The majority of the studies were retrospective and evaluated a single-surgeon's experience. Methods varied considerably, with 66 studies using a single proficiency metric and 47 using more than 1. Operating time was the most commonly used metric. Interval division was the simplest and most commonly used method yet inherent limitations prevent collective synthesis. Regression may accurately describe the learning curve but in practice is hampered by sample size and model choice. CUSUM analyses are of widely varying quality with some being fundamentally flawed and widely misinterpreted however, others provide a reliable view of the learning process. CONCLUSION:There is considerable variation in the quality of existing studies on learning curves in spine surgery. CUSUM analyses, when correctly applied, offer the most reliable estimates. To improve the validity and comparability of future studies, adherence to methodological guidelines is crucial. Multiple or composite performance metrics are necessary for a holistic understanding of the learning process.

Purpose Intra-Discal Vacuum phenomenon (IDVP) is well-recognised, yet poorly visualised and poorly understood radiological finding in disc degeneration, particularly with regard to its role in spinal alignment. CT analysis of the lumbar spine in an aging population aims to identify patterns associated with IDVP including lumbopelvic morphology and associated spinal diagnoses. Methods An analysis was performed of an over-60s population sample of 2020 unrelated abdominal CT scans, without acute spinal presentations. Spinal analysis included sagittal lumbopelvic reconstructions to assess for IDVP and pelvic incidence (PI). Subjects with degenerative pathologies, including previous vertebral fractures, auto-fusion, transitional vertebrae, and listhesis, were also selected out and analysed separately. Results The prevalence of lumbar spine IDVP was 50.3% (955/1898) and increased with age (125 exclusions). This increased in severity towards the lumbosacral junction (L1L2 8.3%, L2L3 10.9%, L3L4 11.5%, L4L5 23.9%, and L5S1 46.3%). A lower PI yielded a higher incidence of IDVP, particularly at L5S1 ( p < 0.01). A total of 292 patients had IDVP with additional degenerative pathologies, which were more likely to occur at the level of isthmic spondylolisthesis, adjacent to a previous fracture or suprajacent to a lumbosacral transitional vertebra ( p < 0.05). Conclusions This study identified the prevalence and severity of IDVP in an aging population. Sagittal patterns that influence the pattern of IVDP, such as pelvic incidence and degenerative pathologies, provide novel insights into the function of aging spines.

Study Design. Narrative literature review. Objective. The aim of this study was to review published literature discussing sustainable health care and to identify aspects that pertain to spine surgery. Summary of Background Data. In recent years, research has investigated the contribution of surgical specialties to climate change. To our knowledge, no article has yet been published discussing the impact specific to spinal procedures and possible mitigation strategies. Methods. A literature search was performed for the present study on relevant terms across four electronic databases. References of included studies were also investigated. Results. Spine surgery has a growing environmental impact. Investigations of analogous specialties find that procurement is the single largest source of emissions. Carbon-conscious procurement strategies will be needed to mitigate this fully, but clinicians can best reduce their impact by adopting a minimalist approach when using surgical items. Reduced wastage of disposable goods and increased recycling are beneficial. Technology can aid remote access to clinicians, and also enable patient education. Conclusions. Spine-surgery–specific research is warranted to evaluate its carbon footprint. A broad range of measures is recommended from preventative medicine to preoperative, intraoperative, and postoperative spine care. Level of Evidence. 5.