RNA-sequencing predicts a role of androgen receptor and aldehyde dehydrogenase 1A1 in osteosarcoma lung metastases.

One-third of pediatric patients with osteosarcoma (OS) develop lung metastases (LM), which is the primary predictor of mortality. While current treatments of patients with localized bone disease have been successful in producing 5-year survival rates of 65-70%, patients with LM experience poor survival rates of only 19-30%. Unacceptably, this situation that has remained unchanged for 30 years. Thus, there is an urgent need to elucidate the mechanisms of metastatic spread in OS and to identify targetable molecular pathways that enable more effective treatments for patients with LM. We aimed to identify OS-specific gene alterations using RNA-sequencing of extremity and LM human tissues. Samples of extremity and LM tumors, including 4 matched sets, were obtained from patients with OS. Our data demonstrate aberrant regulation of the androgen receptor (AR) pathway in LM and predicts aldehyde dehydrogenase 1A1 (ALDH1A1) as a downstream target. Identification of AR pathway upregulation in human LM tissue samples may provide a target for novel therapeutics for patients with LM resistant to conventional chemotherapy.

Quantitative Real-Time Polymerase Chain Reaction May Serve as a Useful Adjunct to Conventional Culture in The Detection of Cutibacterium acnes in the Glenohumeral Joint: A Study of 100 Consecutive Patients.

Objectives: Synovial fluid or tissue culture is the current gold standard for diagnosis of infection, but Cutibacterium acnes (C. acnes) is a frequent cause of shoulder PJI and is a notoriously fastidious organism. The purpose of this study was to compare quantitative real-time polymerase chain reaction (qRT-PCR) to standard culture as a more rapid, sensitive means of identifying C. acnes from the glenohumeral joint. We hypothesized that qRT-PCR would be more effective than standard culture at identifying C. acnes and would have greater sensitivity and specificity for detecting infection. Methods: This was a prospective observational study with 100 consecutive patients undergoing arthroscopic or open shoulder surgery with known positive and negative controls. Intraoperatively, synovial fluid and tissue was obtained for C. acnes qRT-PCR and results were blinded to the gold standard microbiology cultures. Results: Clinical review demonstrated 3 patients (3%) with positive cultures, none of which were positive for C. acnes. Of the samples tested by the C. acnes qRT-PCR standard curve, 12.2% of tissue samples and 4.5% of fluid samples were positive. Culture sensitivity was 60.0%, specificity was 100.0%, PPV was 100.0%, and NPV was 97.9%. C. acnes qRT-PCR standard curve sensitivity, specificity, PPV, and NPV was 60.0%, 90.3%, 25.0%, and 97.7% respectively for tissue specimens and 0%, 95.2%, 0%, and 95.2% respectively, for fluid specimens. For combination of culture and tissue qRT-PCR, the sensitivity, specificity, PPV and NPV was 100%, 90.3%, 35.7%, and 100%, respectively. Conclusion: We report that qRT-PCR for C. acnes identified the organism more frequently than conventional culture. While these findings demonstrate the potential utility of qRT-PCR, the likelihood of false positive results of qRT-PCR should be considered. Thus, qRT-PCR may be useful as an adjuvant to current gold standard workup of synovial fluid or tissue culture for the diagnosis of infection.

Antioxidant 1 copper chaperone gene expression and copper levels in dog osteosarcoma patients.

Twenty-four dogs with OS underwent limb amputation. Serum, OS tumour, and normal bone were harvested at time of surgery. RNA was extracted and gene expression was performed using quantitative polymerase chain reaction (qPCR). Tissue and blood copper concentrations were also determined with spectrophotometry. Compared to bone, tumour samples had significantly higher expressions of antioxidant 1 copper chaperone (ATOX1, p = .0003). OS tumour copper levels were significantly higher than that of serum (p < .010) and bone (p = .038). Similar to our previous observations in mouse and human OS, dog OS demonstrates overexpression of genes that regulate copper metabolism (ATOX1), and subsequent copper levels. Dogs with OS may provide a robust comparative oncology platform for the further study of these factors, as well as potential pharmacologic interventions.

Early initiation of physical therapy after geriatric hip fracture surgery is associated with shorter hospital length of stay and decreased thirty-day mortality.

INTRODUCTION: While the importance of timely surgery and early mobilization are understood in geriatric fracture populations, the relationship between timing of initiation of physical therapy (PT) postoperatively on length of stay (LOS) and mortality has not been well delineated. The purpose of this investigation was to determine the effect of PT initiated on postoperative day zero (POD0) on LOS and mortality in geriatric hip fracture patients. MATERIALS AND METHODS: Patients aged 60 and over who underwent hip fracture surgery, including arthroplasty or internal fixation, between January 2017 and December 2019 at three affiliated academic hospitals were identified. Retrospective chart review and review of hospital charges were used to determine patient demographics, Charlson Comorbidity Index (CCI), surgery performed, timing of postoperative PT visits, LOS, and mortality. RESULTS: Of 1,551 patients identified that met inclusion criteria, 83 (5.3%) received PT on POD0. Most patients (76.3%) received PT on postoperative day 1 (POD1), and 18.4% received first PT on postoperative day 2 or later (POD2+). Time from admission to surgery, CCI, sex, and BMI did not differ significantly between groups. The age difference between patients in the POD0 and the POD1/POD2+ groups was statistically significant with the mean age in the POD1/2+ group being 2.3 years older than the POD0 group (p=0.045). There was no difference in postoperative length of stay (PLOS) based on type of fixation. The average PLOS was 3.4 days in the POD0 PT group compared to 5.2 days in the POD1 group (p<0.0001) and 8.2 days in the POD2+ group (p<0.0001). The POD0/1 group had significantly lower mortality than the POD2+ group [3.7% vs. 9.8%, OR 0.354 (95% CI 0.217-0.575), p<0.0001]. CONCLUSION: Earlier initiation of PT postoperatively is associated with significantly shorter total and postoperative LOS and initiation of PT before POD2 is associated with decreased 30-day mortality. Each day that initiation of PT is delayed is associated with a two- to three-day increase in LOS.

Prognostic factors and survival of patients undergoing surgical intervention for breast cancer bone metastases.

INTRODUCTION: Bone is the most common distant site of breast cancer metastasis. Skeletal lesions can cause significant morbidity due to pain, pathologic fracture, and electrolyte abnormalities. Current treatment for patients with bone metastases (BoM) from breast cancer is highly personalized and often involves a multidisciplinary approach with chemotherapy, hormone therapy, bone-targeted antiresorptive agents, radiation therapy, and surgery. We have retrospectively collected clinical data from a series of patients with bone metastases to evaluate the clinical characteristics, prognostic factors, and survival patterns of patients with breast cancer BoM receiving standard multimodal therapy. METHODS: A consecutive series of 167 patients with breast cancer BoM treated at a single institution between August 2013 and March 2020 were identified. Clinical information was obtained from the medical record and survival analyses were performed to evaluate patient outcomes and identify prognostic factors. RESULTS: Thirty-seven patients (22%) presented with de novo BoM - bone metastases at the time of breast cancer diagnosis - and were 2.6 times more likely to die within the study period than those with asynchronous BoM (HR = 2.62, p = <0.0001). Patients who received bone-targeted medical therapy were 61% less likely to die after BoM diagnosis than those who did not (HR = 0.39, p = 0.001). Operative stabilization of BoM was more frequently employed in patients with lytic (p = 0.02) or mixed (p = 0.02) tumors than it was for those with blastic lesions. Patients treated with surgery had a lower overall bone metastasis survival than those treated without (p < 0.03). DISCUSSION: These findings reflect the current patterns in metastatic breast cancer treatment and associated outcomes. In a series of 167 consecutive patients, we demonstrate the natural history of breast cancer with BoM being treated with modern multimodal therapy. Understanding these treatment patterns and prognostic factors enhances the provider's ability to counsel patients and direct appropriate treatments.

Distal locking of short cephalomedullary nails decreases varus collapse in unstable intertrochanteric fractures - a biomechanical analysis.

INTRODUCTION: Peritrochanteric fractures are a growing problem and complications relating to operative fixation of these fracture, including varus collapse and screw cutout, are common in elderly osteoporotic patients. We hypothesize that unlocked nails will demonstrate increased varus collapse and inferior construct stiffness in specimens with increased diaphyseal medullary diameter. MATERIALS AND METHODS: Sixteen non-cadaveric osteoporotic biomechanical femur specimens were utilized in this study, with eight specimens having an artificially large femoral canal to represent Dorr C femurs. All femurs were instrumented with a short cephalomedullary nail with and without distal cross-lock screw fixation and had an unstable intertrochanteric fracture created in a repeatable pattern. Specimens underwent cyclic compression to a maximal load of 1000N with segmental motion quantified through the use of visual tracking markers. Statistical comparisons were performed using one-way ANOVA with Tukey post-hoc analysis to determine differences between specific groups. Significance was defined as p<0.05. RESULTS: Unlocked short cephalomedullary nails showed increased varus collapse due to motion of the nail within the femoral canal in capacious femoral canals compared with narrow femoral canals and distally cross-locked nails. The coronal deformation of the wide canal unlocked group (17.9 o±2.6o) was significantly greater in the varus direction than any other fixation under compressive load of 1000N. There was no significant difference in varus angulation between the wide canal or narrow canal locked groups (11.1o±8.7o vs. 8.2o±1.7o respectively, p=0.267). The narrow canal unlocked group (13.7o±2.4o) showed significantly greater varus angulation than the narrow canal locked (p=0.015). The wide canal unlocked group showed significantly greater varus angulation than the wide canal locked group (p=0.003). Motion between the femoral shaft and the cephalomedullary nail (toggling of the nail within the shaft) was significantly greater in narrow or wide canal unlocked specimens, 7.94o±2.13o and 10.2o±1.7o respectively, than in the narrow or wide canal locked specimens, 2.4o±0.2o and 4.2o±0.5o respectively (p<0.05) CONCLUSION: Unlocked short intramedullary fixation for unstable peritrochanteric fractures results in increased varus collapse under axial compression. This study supports the use of distal cross-locking of short intramedullary fixation for unstable peritrochanteric fractures in patients with capacious femoral canals secondary to osteoporosis who might otherwise be as risk for varus collapse, device failure, and malunion.

Evaluating the reoperation rate and hardware durability of three stabilizing implants for 105 malignant pathologic humerus fractures.

INTRODUCTION: Many patients sustaining a malignant pathologic humerus fracture (MPHF) elect for surgical stabilization. Complications prompting reoperation can occur, leading to additional quality of life and financial cost. One common event preceding reoperation is a broken implant (BI). The purpose of this study was to identify the rate of reoperation following surgical stabilization of MPHF with three techniques - photodynamic bone stabilization (PBS), intramedullary nail (IMN), and cemented plate fixation (CPF) - and estimate to what extent improved implant durability might prevent reoperation. MATERIALS AND METHODS: Retrospective data collection was performed, identifying 105 procedures (100 patients) who underwent non-articular MPHF surgery from 2010-2016: 19 PBS, 65 IMN, 21 CPF. All patients were followed for at least two years or until death. RESULTS: Reoperation rates were similar at one year (10.5%,6.2%,4.8%, p = 737), two years (15.8%,6.2%,9.5%, p = 375), and final evaluation (15.8%,7.7%,14.3%, p = 248). The rate of BI for PBS, IMN, and CPF was 10.5%,0%, and 4.8% (p = 049 PBS/IMN) at one year, 15.8%,0%, and 9.5% (p = 010 PBS/IMN) at two years, and 15.8%,0%, and 14.3% (p = 010 IMN/PBS, p = 013 IMN/CPF) at final evaluation. CONCLUSIONS: Reoperation rate was not significantly different at any time point. However, IMN surgery resulted in the lowest rate of broken implants (zero), statistically significant versus PBS at all time periods and versus CPF at final follow-up. PBS may eventually offer selected advantages for MPHF management, but current data suggests fragility must be thoughtfully considered.

Comparison of cachectic and non-cachectic sarcoma patients reveals an important role of Notch signaling in metastasis and myogenesis.

Cancer-associated cachexia is a wasting syndrome that affects up to 50% of cancer patients. It is defined as unintentional weight loss ≥5% over 6 months and characterized by muscle atrophy, fatigue, and anorexia that are refractory to nutritional support. Sarcoma describes a diverse group of malignancies arising from the connective tissues. Sarcoma patients are uniquely susceptible to cancer-associated cachexia given its origins in the musculoskeletal system. Our previous research suggests that sarcoma cells may contribute to sarcoma-associated cachexia (SAC) via establishment of TNF-α-mediated inflammation and dysregulation of muscle homeostasis by abnormal Notch signaling. Here, we examine the role of the Notch pathway and pro-inflammatory cytokines in cells derived from cachectic and non-cachectic human sarcoma patients. We observed increased expression of Notch pathway genes in the cachexia group while no differences in pro-inflammatory cytokines were observed. Co-culture of muscle-derived stem cells (MDSCs) and sarcoma cells demonstrated the inhibition of MDSC maturation with both cachectic and non-cachectic patient cells, corresponding to elevated Pax7 and Notch pathway expression in MDSCs. Our findings suggest that there is no difference in inflammatory profile between cachexia and non-cachexia sarcoma samples. However, Cachectic sarcoma samples express increased Notch that mediates muscle wasting possibly through inhibition of myogenesis.

Tumor Resection Guided by Intraoperative Indocyanine Green Dye Fluorescence Angiography Results in Negative Surgical Margins and Decreased Local Recurrence in an Orthotopic Mouse Model of Osteosarcoma.

BACKGROUND: Surgical resection with negative margins is the foundation of extremity sarcoma management. Failure to achieve negative surgical margins can result in local recurrence (LR), a potentially devastating complication. Indocyanine green (ICG) is a US FDA-approved fluorophore previously used to guide carcinoma resections. We investigated the potential of ICG as an intraoperative guide during experimental sarcoma resection. METHODS: Fifty 6-week-old immunocompetent Balb/c female mice received left proximal tibia paraphyseal injections of 5 × 105 K7M2 murine osteosarcoma cells. Animals were separated into two groups (n = 25 each): (1) ICG-assisted surgical resection; and (2) no ICG-assisted resection. Resections were performed 4 weeks after primary tumor engraftment. All animals received 7.5 ug ICG via retro-orbital injection 12 h prior to surgery. ICG fluorescence measurements and clinical evaluations were performed 4 weeks after resection to detect LR. RESULTS: Eleven of 25 animals from each group developed gross tumors. Four weeks after resection, group 1 had 0/11 tumor recurrences, while group 2 had recurrences in 9/11 (81.8%) experimental mice (p < 0.0002) (Fig. 2). There was a 100% NPV in group 1, and no tumor recurrence with fluorescence-free margins after the primary surgery. Group 2 had a 100% positive predictive value for the development of an LR if any fluorescent signal was present at the surgical margin after resection. CONCLUSION: Intraoperative ICG guidance led to reliably negative surgical margins and a diminished LR rate. Given the benign safety profile of ICG and its prior clinical success, these results could be immediately translatable to the clinical realm.