Limb position affects intraoperative assessment of condylar width.

PURPOSE: We sought to define how changes in position and rotation of fluoroscopic imaging may affect the assessment of condylar widening intraoperatively. METHODS: Thirty-three patients with tibial plateau fractures were prospectively identified and included in this study. Fluoroscopic images of the uninjured tibial plateau were obtained in (1) full extension and (2) slight flexion on foam ramp. Beginning with a plateau view, additional views of the tibial plateau were then obtained by rotating the fluoroscope around the knee in 5 degree increments up to 15 degrees in both internal and external rotation. Measurements of distal femoral condylar width (DFW), distal femoral articular width (FAW), proximal tibial articular width (TAW) and lateral plateau width (LPW) were performed. RESULTS: LPW was decreased in flexion compared to extension at all degrees of rotation (p = 0.04-0.00001). There was a trend toward increasing LPW with increasing degrees of internal rotation which reached significance at 15˚ of internal rotation when the knee was flexed. On ANOVA, there was a significant difference of LPW with increasing degree of internal rotation when the knee was in flexion (p = 0.008), but not in extension. There were no differences in DFW, FAW, TAW and DFW/TAW at any point though LPW was decreased in flexion at all degrees of rotation. The FAW/TAW ratio was increased in flexion at all degrees of rotation. DISCUSSION: The knee in flexion will underestimate the measurement of condylar width compared to the knee in full extension, by ~ 2 mm. Rotation of the knee, in comparison, did not have a significant effect on condylar width assessment. LEVEL OF EVIDENCE: Diagnostic II.

Validation of Myc-Associated Protein X (MAX) regulation in growth hormone secreting and nonfunctional pituitary adenoma.

INTRODUCTION: Many patients with growth hormone-secreting pituitary adenoma (GHPA) fail to achieve biochemical remission, warranting investigation into epigenetic and molecular signatures associated with tumorigenesis and hormonal secretion. Prior work exploring the DNA methylome showed Myc-Associated Protein X (MAX), a transcription factor involved in cell cycle regulation, was differentially methylated between GHPA and nonfunctional pituitary adenoma (NFPA). We aimed to validate the differential DNA methylation and related MAX protein expression profiles between NFPA and GHPA. METHODS: DNA methylation levels were measured in 52 surgically resected tumors (37 NFPA, 15 GHPA) at ~100,000 known MAX binding sites derived using ChIP-seq analysis from ENCODE. Findings were correlated with MAX protein expression using a constructed tissue microarray (TMA). Gene ontology analysis was performed to explore downstream genetic and signaling pathways regulated by MAX. RESULTS: GHPA had more hypomethylation events across all known MAX binding sites. Of binding sites defined using ChIP-seq analysis, 1,551 sites had significantly different methylation patterns between the two cohorts; 432 occurred near promoter regions potentially regulated by MAX, including promoters of TNF and MMP9. Gene ontology analysis suggested enrichment in genes involved in oxygen response, immune system regulation, and cell proliferation. Thirteen MAX binding sites were within coding regions of genes. GHPA demonstrated significantly increased expression of MAX protein compared to NFPA. CONCLUSION: GHPA have significantly different DNA methylation and downstream protein expression levels of MAX compared to NFPA. These differences may influence mechanisms involved with cellular proliferation, tumor invasion and hormonal secretion.

Survey Analysis of Orthopedic Call Compensation.

We sought to determine the type, frequency, and compensation details of orthopedic call for orthopedic traumatologists. We administered a 24-question survey to all members of the Orthopaedic Trauma Association regarding the number and type of orthopedic surgeons within the call pool, frequency of call, number of hospitals covered, and compensation for weekday, weekend, holiday, and pediatric calls. A total of 105 orthopedic surgeons replied. The most common number of physicians in the call pool was 6 to 10 (42.9%), whereas the most common number of traumatologists was 0 to 5 (90.5%), with 71.4% taking call at 1 hospital. Further, 56.7% were paid separately for weekday trauma call, with the most common number of call days per week being 2. The most common compensation was $1001 to $1500 (31.6%). For weekend call, 49.5% of physicians were paid separately, with the most common number of weekends on call per year being 11 to 15 (34.3% of replies). For pediatric call, 54.3% of physicians took call, with 28.6% paid separately and 33.3% receiving $0 to $500. For holiday call, 40.2% of physicians were paid separately, with 30.8% receiving $1001 to $1500. We describe the characteristics of traumatology call. Approximately 50% of physicians (range, 28.6%-56.3%) are compensated separately for taking different forms of call (ie, weekday, weekend, holiday). [Orthopedics. 2022;45(5):293-296.].

Radiographic detection of lateral plateau involvement in medial tibial plateau fractures (AO/OTA 41-B1.2, 1.3, 3.2 and 3.3).

PURPOSE: To assess the accuracy of radiographs in detecting the lateral plateau involvement of medial tibial plateau fractures as well as describe the impact of CT on preoperative planning for this specific fracture morphology. METHODS: Radiograph and CT imaging of patients with a Schatzker type IV tibial plateau fractures (AO/OTA 41-B1.2, B1.3 h, B2.2. B3.2, and B3.3) between January 2013 and July 2017 were reviewed by three trauma fellowship-trained orthopedic surgeons to identify fractures of the medial condyle with an intact anterolateral articular surface. RESULTS: Lateral plateau involvement was identified in 16 (37%) radiographs and 26 (61%) CT images (p = 0.051). Radiographic detection of lateral plateau involvement demonstrated a sensitivity of 62% and specificity of 100%, and radiographs were able to predict the recommendation for surgical intervention for lateral plateau involvement with a positive predictive value (PPV) of 75% and a negative predictive value (NPV) of 60% compared to recommendations based on CT imaging. Radiographs predicted a need for a separate surgical approach with PPV of 63% and NPV of 70% when compared to recommendations based on CT images. CONCLUSIONS: Radiographs are reliable in ruling in lateral plateau involvement of medial plateau fractures, but occult lateral articular extension may only be identified in CT imaging for some cases. Surgical planning may be impacted by CT imaging for this fracture morphology, but further study is warranted to evaluate the correlation between preoperative planning and clinical outcomes. LEVEL OF EVIDENCE: III.

Severity of Covid-19 Lockdown Orders Corresponds to Orthopaedic Trauma Volume.

During the Coronavirus Disease 2019 (COVID-19) pandemic, states implemented social distancing guidelines. This study examines the effect of the severity of lockdown orders on orthopaedic trauma volume. Two institutions, one in a state with strict stay home (SH) orders and one in a state with lax social distancing (SD) orders, were examined. Surgical case counts, total orthopaedic case counts, orthopaedic trauma case counts, institution trauma activations, and mechanism of injury data were collected and compared to control periods. For SH versus SD, total surgical cases decreased 48.6% vs. 62%; orthopaedic cases decreased 51.8% vs. 62%, and orthopaedic trauma cases decreased 34% v. 0%. Orthopaedic trauma cases comprised more of both institutions' total cases. Total surgical cases decreased at both SH and SD, but orthopaedic trauma cases did not decrease at SD. More strict social distancing orders correlate with greater reduction in orthopaedic trauma cases. (Journal of Surgical Orthopaedic Advances 31(4):222-225, 2022).

Treatment of tibial plateau fractures with a novel fenestrated screw system for delivery of bone graft substitute.

PURPOSE: The purpose of this study was to describe the incidence of subsidence in patients with AO/OTA 41 (tibial plateau) fractures which were repaired with a novel fenestrated screw system to used to deliver CaPO4 bone substitute material to fill the subchondral void and support the articular reduction. METHODS: Patients with unicondylar and bicondylar tibial plateau fractures were treated according to the usual technique of two surgeons. After fixation, the Zimmer Biomet N-Force Fixation System®, a fenestrated screw that allows for the injection of bone substitute was placed and used for injection of the proprietary calcium phosphate bone graft substitute into the subchondral void. For all included patients, demographic information, operative data, radiographs, and clinic notes were reviewed. Patients were considered to have articular subsidence if one or more of two observations were made when comparing post-operative to their most recent clinic radiographs: > 2 mm change in the distance between the screw and the lowest point of the tibial plateau, > 2 mm change in the distance between the screw and the most superior aspect of the plate. Data were analyzed to determine if there were any identifiable risk factors for complication, reoperation, or subsidence using logistic regression. Statistical significance was set at p < 0.05. RESULTS: 34 patients were included with an average follow-up of 32.03 ± 22.52 weeks. There were no overall differences between height relative to the medial plateau or the plate. Two patients (5.9%) had articular subsidence. Six patients (15.2%) underwent reoperation, two (6%) for manipulations under anaesthesia due to arthrofibrosis, and four (12%) due to infections. There were 6 (19%) total infections as 2 were superficial and required solely antibiotics. One patient had early failure. CONCLUSION: Use of a novel fenestrated screw system for the delivery of CaPO4 BSM results in articular subsidence and complication rates similar to previously published values and appears to be a viable option for addressing subchondral defects in tibial plateau fractures. LEVEL OF EVIDENCE: IV.

Long-Term Tumor Control Rates Following Gamma Knife Radiosurgery for Acoustic Neuroma.

BACKGROUND: Acoustic neuromas (ANs) are benign intracranial tumors that arise from myelin-forming Schwann cells surrounding the vestibular branch of the vestibulocochlear nerve (cranial nerve VIII). Treatment options for AN include observation, radiosurgery, and microsurgical resection. Gamma Knife radiosurgery (GKRS) for AN has well-documented short-term safety and efficacy for carefully selected patients. Recent innovations in GKRS technology may improve long-term outcomes. The aim of this study was to report long-term tumor control and complication rates after GKRS for sporadic AN. METHODS: A retrospective review was performed of patients with sporadic ANs at Keck Hospital of USC who underwent GKRS from 1995 to 2015 with a minimum follow-up of 12 months. RESULTS: Median age at treatment was 63.7 years (range, 19.4-84.2 years). Median follow-up time was 69 months. Median tumor diameter was 17.5 mm (range, 5.0-29.0 mm), and median treatment volume was 2.41 cm3 (range, 0.09-12.8 cm3). Median prescribed dose was 12.50 Gy. Tumor control was achieved in 51 (98.1%) patients over the follow-up period (12-192 months). One patient experienced tumor progression at 22 months after GKRS, requiring surgical intervention, which ultimately resulted in remission. Complications included hearing loss (17.3%), worsened balance/ataxia (7.7%), and hydrocephalus (1.92%). CONCLUSIONS: Patients undergoing GKRS for sporadic ANs had high rates of tumor control over a median follow-up time of >5 years. Improvements in radiosurgery treatment planning were seen in the most recent cohort of patients. GKRS is a safe and effective modality for treating sporadic ANs in selected patients.

Epigenetic Reprogramming Strategies to Reverse Global Loss of 5-Hydroxymethylcytosine, a Prognostic Factor for Poor Survival in High-grade Serous Ovarian Cancer.

Purpose: A major challenge in platinum-based cancer therapy is the clinical management of chemoresistant tumors, which have a largely unknown pathogenesis at the level of epigenetic regulation.Experimental Design: We evaluated the potential of using global loss of 5-hydroxymethylcytosine (5-hmC) levels as a novel diagnostic and prognostic epigenetic marker to better assess platinum-based chemotherapy response and clinical outcome in high-grade serous tumors (HGSOC), the most common and deadliest subtype of ovarian cancer. Furthermore, we identified a targetable pathway to reverse these epigenetic changes, both genetically and pharmacologically.Results: This study shows that decreased 5-hmC levels are an epigenetic hallmark for malignancy and tumor progression in HGSOC. In addition, global 5-hmC loss is associated with a decreased response to platinum-based chemotherapy, shorter time to relapse, and poor overall survival in patients newly diagnosed with HGSOC. Interestingly, the rescue of 5-hmC loss restores sensitivity to platinum chemotherapy in vitro and in vivo, decreases the percentage of tumor cells with cancer stem cell markers, and increases overall survival in an aggressive animal model of platinum-resistant disease.Conclusions: Consequently, a global analysis of patient 5-hmC levels should be included in future clinical trials, which use pretreatment with epigenetic adjuvants to elevate 5-hmC levels and improve the efficacy of current chemotherapies. Identifying prognostic epigenetic markers and altering chemotherapeutic regimens to incorporate DNMTi pretreatment in tumors with low 5-hmC levels could have important clinical implications for newly diagnosed HGSOC disease. Clin Cancer Res; 24(6); 1389-401. ©2017 AACR.