Hip Preservation and Capanna Reconstruction for Pediatric Proximal Femur Ewing Sarcoma: A Report of 2 Cases.

CASE: This is a first report describing preservation of the femoral head by transcervical resection of proximal femoral Ewing sarcoma in 2 pediatric patients. A unique Capanna reconstruction supported joint salvage. At 1 year, Pediatric Outcomes Data Collection Instrument and Pediatric Toronto Extremity Salvage Score outcomes were excellent. Surveillance magnetic resonance imaging was without evidence of recurrence or impaired perfusion to the femoral head. CONCLUSION: We demonstrate the feasibility of hip joint preservation and maintenance of femoral head viability after transcervical resection of pediatric proximal femur bone sarcomas while preserving the medial circumflex femoral artery. This technique may be a preferred option over joint sacrifice and endoprosthetic replacement in young patients when tumor margins permit.

Thematic analysis of online discussion forums for soft tissue sarcomas.

BACKGROUND AND OBJECTIVES: As there is an increasing reliance on the internet for medical information, patients diagnosed with rare diseases have turned to online community forums to share information about their diagnoses. These forums help patients to gather and share information about their experience with disease. Additionally, these platforms enable patients to build unique connections based on their shared experiences. The objective of this study was to review shared posts in online community forums by individuals with soft tissue sarcomas to better understand commonly discussed themes. This information may improve the physicians' understanding of patients' concerns and feelings at the time of diagnosis and treatment. METHODS: We entered "sarcoma discussion forum" in search engines to identify internet discussion boards. Four major discussion forums were analyzed, and posts written between January 1, 2017 through May 1, 2022 addressing soft tissue sarcomas present in the upper and lower extremities were collected. Each post was analyzed by the two investigators in three steps (open coding, axial coding, and selective coding). RESULTS: A total of 506 posts were included in the final analysis. We used twenty-seven axial codes and four selective codes. Emotional Aspects/Connecting with Others was the most common theme (77 % of posts) followed by Information Support: Treatment (38 % of posts), Information Support: Diagnosis (24 % of posts) and Information Support: Recovery (21 % of posts). CONCLUSIONS: The most prevalent theme was centered on emotional aspects of these patients' journeys, highlighting the importance of providing resources to address emotional support for patients with soft tissue sarcoma and their families. LEVEL IV: Qualitative research study.

Multimodal management of tenosynovial giant cell tumors (TGCT) in the landscape of new druggable targets.

Tenosynovial giant cell tumor (TGCT) is a rare, benign, locally aggressive synovial based neoplastic process that can result in functional debilitation and end-stage arthrtitis. Although surgical resection is the primary treatment modality, novel systemic therapies are emerging as part of the multimodal armamentarium for patients with unresectable or complex disease burden. This review discusses the pathogenesis of TGCT, potential druggable targets and therapeutic approaches. It also evaluates the safety and efficacy of different systemic therapies.

Risk Factors for All-Cause Early Reoperation Following Tumor Resection and Endoprosthetic Reconstruction: A Secondary Analysis from the PARITY Trial.

BACKGROUND: Oncologic resection and endoprosthetic reconstruction of lower-extremity musculoskeletal tumors are complex procedures fraught with multiple modes of failure. A robust assessment of factors contributing to early reoperation in this population has not been performed in a large prospective cohort. The aim of the present study was to assess risk factors for early reoperation in patients who underwent tumor excision and endoprosthetic reconstruction, with use of data from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial. METHODS: Baseline characteristics were assessed, including age, sex, tumor type, tumor location, presence of a soft-tissue mass, diabetes, smoking status, chemotherapy use, and neutropenia. Operative factors were recorded, including operative time, topical antibiotics, silver-coated prosthetics, endoprosthetic fixation, extra-articular resection, length of bone resected, margins, tranexamic acid, postoperative antibiotics, negative-pressure wound therapy, and length of stay. Univariate analysis was utilized to explore the differences between patients who did and did not undergo reoperation within 1 year postoperatively, and a multivariate Cox proportional hazards regression model was utilized to explore the predictors of reoperation within 1 year. RESULTS: A total of 155 (25.7%) of 604 patients underwent ≥1 reoperation. In univariate analysis, tumor type (p < 0.001), presence of a soft-tissue mass (p = 0.045), operative time (p < 0.001), use of negative-pressure wound therapy (p = 0.010), and hospital length of stay (p < 0.001) were all significantly associated with reoperation. On multivariate assessment, tumor type (benign aggressive bone tumor versus primary bone malignancy; hazard ratio [HR], 0.15; 95% confidence interval [CI], 0.04 to 0.63; p = 0.01), operative time (HR per hour, 1.15; 95% CI, 1.10 to 1.23; p < 0.001), and use of negative-pressure wound therapy (HR, 1.93; 95% CI, 1.30 to 2.90; p = 0.002) remained significant predictors of reoperation within 1 year. CONCLUSIONS: Independent variables associated with reoperation within 1 year in patients who underwent tumor resection and endoprosthetic reconstruction included tumor type (benign aggressive bone tumor versus primary bone malignancy), operative time, and use of negative-pressure wound therapy. These results will help to inform patients and surgeons regarding the risk of reoperation by diagnosis and reinforce operative time as a factor influencing reoperation. These results also support further investigation into the use of negative-pressure wound therapy at the time of surgery in this patient population. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Most Patients With Bone Sarcomas Seek Emotional Support and Information About Other Patients' Experiences: A Thematic Analysis.

BACKGROUND: Online discussion forums allow individuals who otherwise may be strangers to create a community where they can seek and share information. Patients with bone sarcomas and their support networks use discussion forums dedicated to cancer support. There is a paucity of published reports regarding the care experience of patients with bone sarcomas because studies on online discussion groups have primarily focused on some of the more common cancers, including breast and prostate cancer. Understanding commonly discussed themes among patients with bone sarcomas would allow treating physicians to have a better understanding of patient concerns when providing patient education and counseling. QUESTION/PURPOSE: We performed this study to review posts from bone sarcoma internet discussion boards to establish common themes related to the care experience of patients with sarcomas. METHODS: Online discussion forums were identified using the search term "sarcoma discussion forum." After identifying 12 websites, we excluded closed forum groups, websites with missing or invalid links to forums, and nonpublic forums, such as groups on Facebook. These websites include profiles and photos that are personal, and sufficient author anonymity could not be achieved for this study. Posts written between January 1, 2012, and May 1, 2022, posted on five discussion boards were reviewed and collected until we reached a point of data saturation in which we agreed that the collection of additional posts would not reveal new themes. Discussion threads were filtered to identify posts pertaining to the most common bone sarcomas: chondrosarcoma, Ewing sarcoma, and osteosarcoma. Grounded theory-the methodology of repeated analyses of qualitative data to identify recurring themes or concepts-was used to analyze posts. Caregiver posts were delineated from patient posts and categorized separately for subgroup analysis. Grounded theory, although a qualitative method, endeavors to integrate the strengths inherent in quantitative methods with qualitative approaches. Grounded theory categorizes words, language, and the meanings these imply and seeks to organize and reduce the data gathered into themes or essences, which, in turn, can be fed into descriptions, models, or theories. Our analysis used three reviews of text to assign and group codes based on repeating ideas or concepts. The first review (open coding) aims to assign codes based on the verbatim text included by the author to capture the specific thoughts and ideas of the post. The second review (axial coding) aims to consolidate the ideas of posts by applying broader concepts to each post. The third and final review (selective coding) aims to further consolidate the themes of each post by trying to embody the main message contained in a post. A total of 570 posts from 139 threads were collected and analyzed using grounded theory. Twenty-five axial codes and four selective codes were created. We defined data saturation by the absence of a new open code in the analysis of a block of 50 posts to ensure that signals of saturation were not accepted too early in the analysis. RESULTS: The four selective codes included emotional aspects or connecting with others, information support: diagnosis, information support: treatment, and information support: recovery. Of these four codes, emotional aspects and connecting with others was the most prevalent theme (78% [445 of 570] of posts) followed by information support: treatment (49% [282 of 570] of posts). Information support: diagnosis and information support: recovery were each captured in 15% of posts. CONCLUSION: Analysis of posts reveals that the two most common themes involve seeking out emotional support and information about the experiences of others with various treatment modalities. Although most of the posts we assessed contained experiential information and emotional support rather than directed medical advice, future studies should assess the accuracy of information shared among online sarcoma forums. CLINICAL RELEVANCE: Physicians caring for patients with sarcomas should not only address patient concerns related to medical care, but also provide emotional support directly and assist patients by providing resources to peer support outlets, including online discussion forums. Although we cannot ascertain the proportion of patients who use online sites given the anonymity of posts included, these findings suggest common experiential themes across patients with sarcomas outside their doctors' offices. It is important that providers be aware of reputable forums to provide as resources for their patients. The Musculoskeletal Tumor Society may further benefit from endorsing one or more of these forums and providing physician oversight to monitor misinformation.

Proximal Femur Replacements for an Oncologic Indication Offer a Durable Endoprosthetic Reconstruction Option: A 40-year Experience.

BACKGROUND: Proximal femur replacements (PFRs) are an effective surgical option to treat primary and metastatic tumors causing large bony defects in the proximal femur. Given the relative rarity of these indications, current studies on PFR for oncologic indications are generally limited by patient volume or relatively short-term follow-up. Because recent advances in systemic therapy have improved the prognosis of patients who undergo limb salvage surgery for musculoskeletal tumors, data on the long-term durability of endoprosthetic reconstructions have become increasingly important. QUESTIONS/PURPOSES: (1) How does the long-term survival of cemented bipolar PFRs compare with patient survival in patients who underwent PFR for benign, aggressive, and metastatic tumors? (2) What are common reasons for revisions of primary PFRs? (3) Which factors are associated with survival of primary PFRs? (4) What is the survivorship free from conversion of bipolar PFRs to THA? METHODS: Between January 1, 1980, and December 31, 2020, we treated 812 patients with an endoprosthetic reconstruction for an oncologic indication. All patients who underwent a primary PFR for an oncologic indication were included in this study. The study cohort consisted of 122 patients receiving a primary PFR. Eighteen patients did not reach a censored endpoint such as death, revision, or amputation within 2 years. Thirty-three patients died within 2 years of their surgery. Of the 122 patients with primary PFRs, 39 did not reach a censored endpoint and have not been seen within the past 5 years. However, the mean follow-up time for these patients was longer than 10 years. The Social Security Death Index was queried to identify any patients who may have died but might not have been captured by our database To allow for adequate follow-up, endoprosthetic reconstructions performed after December 31, 2020 were excluded. The mean age at the time of the index surgery was 48 ± 22 years. The mean follow-up time of surviving patients was 7 ± 8 years. All PFRs were performed using a bipolar hemiarthroplasty with a cemented stem, and all implants were considered comparable. Demographic, oncologic, procedural, and outcome data including prosthesis survival, patient survival, complication rates, and rates of conversion to THA were analyzed. Patient, prosthesis, and limb salvage survival rates were generated, with implant revision as the endpoint and death as a competing risk. Statistical significance was defined as p < 0.05. RESULTS: Generally, patients with benign or low-grade (Stage I) disease outlived their implants (100% patient survival through 30 years; p = 0.02), whereas the opposite was true in patients with high-grade, localized Stage II disease (64% patient survival at 5 years [95% CI 49% to 76%]; p = 0.001) or widespread Stage III metastatic disease (6.2% patient survival at 5 years [95% CI 0.5% to 24%]; p < 0.001). Primary PFR implant survival at 5, 10, 20, and 30 years was 97% (95% CI 90% to 99%), 81% (95% CI 67% to 90%), 69% (95% CI 46% to 84%), and 51% (95% CI 24% to 73%), respectively. Eight percent (10 of 122) of primary PFRs were revised for any reason. The most common causes of revision were aseptic loosening (3% [four of 122]), infection (3% [three of 122]), breakage of the implant (2% [two of 122]), and tumor progression (1% [one of 122]). Follow-up time was the only factor that was associated with revision of primary PFRs. Neither segment length nor stem length were associated with revision of primary. Six percent (seven of 122) of PFRs were converted to THA at a mean 15 ± 8 years from the index procedure. Survivorship free from conversion to THA (accounting for death as a competing risk) was 94% (95% CI 85% to 99%), 86% (95% CI 68% to 94%). and 77% (95% CI 51% to 91%) at 10, 20, and 30 years, respectively. CONCLUSION: Cemented bipolar PFRs for an oncologic indication are a relatively durable reconstruction technique. Given the relative longevity and efficacy of PFRs demonstrated in our study, especially in patients with high-grade or metastatic disease where implant survival until all-cause revision was longer than patient survival, surgeons should continue to seriously consider PFRs in appropriate patients. The relative rarity of these reconstructions limits the number of patients in this study as well as in current research; thus, further multi-institutional collaborations are needed to provide the most accurate prognostic data for our patients. LEVEL OF EVIDENCE: Level III, therapeutic study.

What are the indications and survivorship of tumor endoprosthetic reconstructions for patients with extremity metastatic bone disease?

BACKGROUND AND OBJECTIVES: Given advances in therapies, endoprosthetic reconstruction (EPR) in metastatic bone disease (MBD) may be increasingly indicated. The objectives were to review the indications, and implant and patient survivorship in patients undergoing EPR for MBD. METHODS: A review of patients undergoing EPR for extremity MBD between 1992 and 2022 at two centers was performed. Surgical data, implant survival, patient survival, and implant failure modes were examined. RESULTS: One hundred fifteen patients were included with a median follow-up of 14.9 months (95% confidence interval [CI]: 9.2-19.3) and survival of 19.4 months (95% CI: 13.6-26.1). The most common diagnosis was renal cell carcinoma (34/115, 29.6%) and the most common location was proximal femur (43/115, 37.4%). Indications included: actualized fracture (58/115, 50.4%), impending fracture (30/115, 26.1%), and failed fixation (27/115, 23.5%). Implant failure was uncommon (10/115, 8.7%). Patients undergoing EPR for failed fixation were more likely to have renal or lung cancer (p = 0.006). CONCLUSIONS: EPRs were performed most frequently for renal cell carcinoma and in patients with a relatively favorable survival. EPR was indicated for failed previous fixation in 23.5% of cases, emphasizing the importance of predictive survival modeling. EPR can be a reliable and durable surgical option for patients with MBD.

Cancer-Associated B Cells in Sarcoma.

Despite being one of the first types of cancers studied that hinted at a major role of the immune system in pro- and anti-tumor biology, little is known about the immune microenvironment in sarcoma. Few types of sarcoma have shown major responses to immunotherapy, and its rarity and heterogeneity makes it challenging to study. With limited systemic treatment options, further understanding of the underlying mechanisms in sarcoma immunity may prove crucial in advancing sarcoma care. While great strides have been made in the field of immunotherapy over the last few decades, most of these efforts have focused on harnessing the T cell response, with little attention on the role B cells may play in the tumor microenvironment. A growing body of evidence suggests that B cells have both pro- and anti-tumoral effects in a large variety of cancers, and in the age of bioinformatics and multi-omic analysis, the complexity of the humoral response is just being appreciated. This review explores what is currently known about the role of B cells in sarcoma, including understanding the various B cell populations associated with sarcoma, the organization of intra-tumoral B cells in tertiary lymphoid structures, recent trials in immunotherapy in sarcoma, intra-tumoral immunoglobulin, the pro-tumor effects of B cells, and exciting future areas for research.

Lifelong Imaging Surveillance is Indicated for Patients with Primary Retroperitoneal Liposarcoma.

BACKGROUND: Surveillance imaging of patients with retroperitoneal liposarcoma (RP-LPS) after surgical resection is based on a projected risk of locoregional and distant recurrence. The duration of surveillance is not well defined because the natural history of RP-LPS after treatment is poorly understood. This study evaluated the long-term risk of recurrence and disease-specific survival (DSS) for a cohort of patients with at least 10 years of progression-free survival (10yr-PFS) from their primary resection. METHODS: The prospective University of California, Los Angeles (UCLA) Sarcoma Database identified RP-LPS patients with 10yr-PFS after initial resection. The patients in the 10yr-PFS cohort were subsequently evaluated for recurrence and DSS. The time intervals start at date of initial surgical resection. Cox proportional hazards models were used to determine factors associated with recurrence and DSS. RESULTS: From 1972 to 2010, 76 patients with RP-LPS had at least 10 years of follow-up evaluation. Of these 76 patients, 39 (51%) demonstrated 10yr-PFS. The median follow-up period was 15 years (range 10-33 years). Among the 10yr-PFS patients, 49% (19/39) experienced a recurrence at least 10 years after surgery. Of those who experienced recurrence, 42% (8/19) died of disease. Neither long-term recurrence nor DSS were significantly associated with age, sex, tumor size, LPS subtype, surgical margin, or perioperative treatment with radiation or chemotherapy. CONCLUSION: Patients who have primary RP-LPS treated with surgical resection ± multimodality therapy face a long-term risk of recurrence and disease-specific death unacknowledged by current surveillance imaging guidelines. Among the patients with 10yr-PFS, 49% experienced a recurrence, and 42% of those died of disease. These findings suggest a need for lifelong surveillance imaging for patients with RP-LPS.

A population-based analysis of the presentation and outcomes of pediatric patients with osteosarcoma in Canada: a report from CYP-C.

BACKGROUND: Frequently occurring in adolescents, osteosarcoma is the most common primary malignant bone disease, with a reported 15% of patients who present with metastasis. With advances in imaging and improvements in surgical care, an updated analysis is warranted on the outcomes of pediatric patients with osteosarcoma. METHODS: We completed a retrospective review of pediatric patients who presented with osteosarcoma between 2001 and 2017, using The Cancer in Young People in Canada (CYP-C) national database. Data on 304 patients aged younger than 15 years were analyzed. RESULTS: The proportion of patients who presented with metastasis was 23.0%. The overall 5-year survival (OS) for patients who presented with metastasis was 37.4%. Overall survival and event-free survival (EFS) were lower in these patients than in patients with localized disease (hazard ratio [HR] 4.3, p < 0.0001 and HR 3.1, p < 0.0001). For patients who presented with metastatic disease, the OS for those undergoing an operative intervention was 44.1% compared with 17.6% for those who did not undergo resection (p < 0.0001). CONCLUSION: The proportion of patients who presented with metastatic osteosarcoma in our population is higher than previously reported. Overall outcomes of patients with metastatic disease have not changed. Our data reaffirm a role for surgical resection in patients with metastasis with a need to explore new treatment strategies to improve the overall prognosis of these patients.

Low-Dose Aspirin for Venous Thromboembolism Prophylaxis is Associated With Lower Rates of Periprosthetic Joint Infection After Total Joint Arthroplasty.

BACKGROUND: Aspirin as a venous thromboembolism (VTE) prophylactic agent has been shown to have antistaphylococcal and antibiofilm roles. Optimal acetylsalicylic acid (ASA) dosage would facilitate antimicrobial effects while avoiding over-aggressive inhibition of platelet antimicrobial function. Our purpose was to determine the periprosthetic joint infection (PJI) rate after total joint arthroplasty in patients receiving low-dose ASA (81 mg twice a day), in comparison to high-dose ASA (325 mg twice a day). METHODS: We conducted a retrospective cohort study between 2008 and 2020. Eligible patients were older than 18 years, underwent primary total joint arthroplasty, both total knee arthroplasty and total hip arthroplasty, had a minimum 30-day follow-up, and received a full course ASA as VTE prophylaxis. Patients' records were reviewed for PJI, according to Musculoskeletal Infection Society criteria. Patients were excluded if they underwent revision arthroplasty, had a history of coagulopathy, or had an ASA regimen that was not completed. In total 15,825 patients were identified, 8,761 patients received low-dose ASA and 7,064 received high-dose ASA. RESULTS: The high-dose cohort had a higher PJI rate (0.35 versus 0.10%, P = .001). This relationship was maintained when comparing subgroups comprising total knee arthroplasty (0.32 versus 0.06%, P = .019) or total hip arthroplasty (0.38 versus 0.14%, P = .035) and accounting for potentially confounding demographic and surgical variables (odds ratio = 2.59, 95% CI = 1.15-6.40, P = .028). CONCLUSION: Comparing low-dose to high-dose ASA as a VTE prophylactic agent, low-dose ASA had a lower PJI rate. This may be attributable to a balance of anti-infective properties of ASA and antiplatelet effects.

Does surgical technique influence the burden of lung metastases in patients with pathologic long bone fractures?

BACKGROUND: The aims of this study are to (1) determine whether fixation of metastatic long bone fractures with an intramedullary nail (IMN) influences the incidence of lung metastasis in comparison to arthroplasty or ORIF (Arthro/ORIF); and (2) assess this relationship in primary tumor types; and (3) to assess survival implications of lung metastasis after surgery. METHODS: Retrospective cohort study investigating 184 patients (107 IMN, and 77 Arthro/ORIF) surgically treated for metastatic long bone fractures. Patients were required to have a single surgically treated impending or established pathologic fracture of a long bone, pre-operative lung imaging (lung radiograph or computed tomography) and post-operative lung imaging within 6 months of surgery. Primary cancer types included were breast (n = 70), lung (n = 43), prostate (n = 34), renal cell (n = 37). Statistical analyses were conducted using two-tailed Fisher's exact tests, and Kaplan-Meier survival analyses. RESULTS: Patients treated with IMN and Arthro/ORIF developed new or progressive lung metastases following surgery at an incidence of 34 and 26%, respectively. Surgical method did not significantly influence lung metastasis (p = 0.33). Furthermore, an analysis of primary cancer subgroups did not yield any differences between IMN vs Arthro/ORIF. Median survival for the entire cohort was 11 months and 1-year overall survival was 42.7% (95% CI: 35.4-49.8). Regardless of fixation method, the presence of new or progressive lung metastatic disease at follow up imaging study was found to have a negative impact on patient survival (p < 0.001). CONCLUSIONS: In this study, development or progression of metastatic lung disease was not affected by long bone stabilization strategy. IM manipulation of metastatic long bone fractures therefore may not result in a clinically relevant increase in metastatic lung burden. The results of this study also suggest that lung metastasis within 6 months of surgery for metastatic long bone lesions is negatively associated with patient survival. LEVEL OF EVIDENCE: III, therapeutic study.

Longitudinal survival trends of patients with cancer with surgically managed appendicular metastatic bone disease: systematic review.

BACKGROUND: Advances in systemic cancer therapies have improved survival for patients with metastatic carcinoma; however, it is unknown whether these advances have translated to improved survival for patients with appendicular metastatic bone disease (A-MBD) after orthopedic interventions. We conducted a study to evaluate the trend in overall survival for patients who underwent orthopedic surgery for A-MBD between 1968 and 2018. METHODS: A systematic search of Embase and Medline to identify studies published since 1968 evaluating patients treated with orthopedic surgery for A-MBD was conducted for a previously published scoping review. We used a meta-regression model to assess the longitudinal trends in 1-, 2- and 5-year overall survival between 1968 and 2018. The midpoint year of patient inclusion for each study was used for analysis. We categorized primary tumour types into a tumour severity score according to prognosis for a further meta-regression analysis. RESULTS: Of the 5747 studies identified, 103 were retained for analysis. Meta-regression analysis showed no significant effect of midpoint study year on survival across all time points. There was no effect of the weighted average of tumour severity scores for each study on 1-year survival over time. CONCLUSION: There was no significant improvement in overall survival between 1968 and 2018 for patients with A-MBD who underwent orthopedic surgery. Orthopedic intervention remains a poor prognostic variable for patients with MBD. This finding highlights the need for improved collection of prospective data in this population to identify patients with favourable survival outcomes who may benefit from personalized oncologic surgical interventions.

Thromboembolic complications after surgical fixation of bone metastases: A systematic review.

BACKGROUND: Patients undergoing a major orthopedic surgery for metastatic bone disease (MBD) are at high risk of developing venous thromboembolic (VTE) complications. Despite concerns, there is no consensus on the most effective strategy to prevent VTE in these patients. The purpose of this systematic review was to determine the VTE rate following the surgical management of MBD. METHODS: The databases MEDLINE, EMBASE, and CENTRAL were searched using keywords related to VTE and MBD requiring surgical management. Included studies reported VTE rates in patients with surgically managed MBD. Descriptive statistics and weighted mean totals were calculated. RESULTS: In total, 2082 abstracts were screened, and 29 studies were included. The overall VTE rate was 4.7%. Patients receiving surgery for impending pathologic fracture had a higher rate of VTE (5.6%) compared to patients with acute pathologic fractures (4.2%). Low-molecular-weight heparin was the most used chemoprophylaxis. CONCLUSIONS: Relative to other cancer and orthopedic patients, the VTE rate is extremely high in patients with MBD. The discordant recommendations of thromboprophylaxis, and absence of research in this distinct and more granular surgical oncology subgroup, underpins the challenges associated with developing guidelines to lessen the VTE risks in the MBD patient population.

Outcomes and complications after dual plate vs. single plate fixation of displaced mid-shaft clavicle fractures: A systematic review and meta-analysis.

INTRODUCTION: Open reduction and internal fixation (ORIF) of displaced midshaft clavicle fractures is associated with higher union rates and earlier functional recovery. However, ORIF with plate fixation is associated with complications including implant irritation and implant failure. Dual plate fixation provides fixation in orthogonal planes, and uses a lower profile fixation technique in comparison to pre-contoured and surgeon-contoured small-fragment locking plates, which may be more prominent. The objective of this study was to conduct a systematic review to summarize outcomes and complications associated with surgical fixation of displaced acute midshaft clavicle fractures with dual plate fixation. METHODS: Using a predetermined study protocol in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, the databases MEDLINE, EMBASE, and CENTRAL were searched from inception to 2020 to identify studies reporting outcomes in acute midshaft clavicle fractures treated with dual plate fixation. All clinical studies which reported on outcomes of dual plating in patients with acute midshaft clavicle fractures were included. Baseline demographics, plate fixation constructs, fracture union rates, implant removal rates, maintenance of reduction, symptomatic implant rates, wound complications, and functional outcomes were extracted. All extracted data were recorded, and descriptive statistics were summarized. Meta-analysis was performed on fracture union rates and implant removal rates using random-effects modeling using Mantel-Haenszel weighting. RESULTS: Our literature search identified 2226 unique abstracts, of which eight studies met our study inclusion criteria following review. A total of 278 patients made up of 79.8% male with an average age of 36.0 years were included. The overall dual plate implant removal rate was 4.2% with excellent rates of union reported. Moreover, single plate fixation was associated with a 3.9-fold increased implant removal rate compared to dual plate fixation. CONCLUSION: Results from this systematic review demonstrate that ORIF of displaced midshaft clavicle fractures using a dual plate fixation technique is a viable option to reduce the incidence of implant removal, without negatively impacting the rate of fracture union. LEVEL OF EVIDENCE: Therapeutic Level III.

Is Use of BMP-2 Associated with Tumor Growth and Osteoblastic Differentiation in Murine Models of Osteosarcoma?

BACKGROUND: The putative benefit of rhBMP-2 is in the setting of limb reconstruction using structural allografts, whether it be allograft-prosthetic composites, osteoarticular allografts, or intercalary segmental grafts. There are also potential advantages in augmenting osseointegration of uncemented endoprosthetics and in reducing infection. Recombinant human BMP-2 might mitigate nonunion in structural allograft augmented osteosarcoma limb salvage surgery; however, its use is limited because of concerns about the prooncogenic effects of the agent. QUESTIONS/PURPOSES: (1) To assess if BMP-2 signaling influences osteosarcoma cell line growth. (2) To characterize degree of osteosarcoma cell line osteoblastic differentiation in response to BMP-2. (3) To assess if BMP-2 signaling has a consistent effect on local or systemic tumor burden in various orthotopic murine models of osteosarcoma. METHODS: In this study, 143b, SaOS-2 and DLM8-M1 osteosarcoma cell lines were transfected with BMP-2 cDNA controlled by a constitutive promoter (experimental) or an empty vector (control) using a PiggyBac transposon system. Cellular proliferation was assessed using a quantitative MTT colorimetric assay. Osteoblastic differentiation was compared between control and experimental cell lines using quantitative real-time polymerase chain reaction of the osteoblastic markers connective tissue growth factor, Runx-2, Osterix, alkaline phosphatase and osteocalcin. Experimental and control cell lines were injected into the proximal tibia of either NOD-SCID (143b and SaOS-2 xenograft model), or C3H (DLM8-M1 syngeneic model) mice. Local tumor burden was quantitatively assessed using tumor volume caliper measurements and bioluminescence, and qualitatively assessed using post-mortem ex vivo microCT. Lung metastasis was qualitatively assessed by the presence of bioluminescence, and incidence was confirmed using histology. rhBMP-2 soaked absorbable collagen sponges (experimental) and sterile-H2O soaked absorbable collagen sponges (control) were implanted adjacent to 143b proximal tibial cell line injections to compare the effects of exogenous BMP-2 application with endogenous upregulation. RESULTS: Constitutive expression of BMP-2 increased the in vitro proliferation of 143b cells (absorbance values 1.2 ± 0.1 versus 0.89 ± 0.1, mean difference 0.36 [95% CI 0.12 to 0.6]; p = 0.01), but had no effect on SaOS-2 and DLM8-M1 cell proliferation. In response to constitutive BMP-2 expression, 143b cells had no differences in osteoblastic differentiation, while DLM8-M1 cells downregulated the early marker connective tissue growth factor (mean ΔCt 0.2 ± 0.1 versus 0.6 ± 0.1; p = 0.002) and upregulated the early-mid range marker Runx-2 (mean ΔCt -0.8 ± 0.1 versus -1.1 ± 0.1; p = 0.002), and SaOS-2 cells upregulated the mid-range marker Osterix (mean ΔCt -2.1 ± 0.6 versus -3.9 ± 0.6; p = 0.002). Constitutive expression of BMP-2 resulted in greater 143b and DLM8-M1 local tumor volume (143b: 307.2 ± 106.8 mm versus 1316 ± 387.4 mm, mean difference 1009 mm [95% CI 674.5 to 1343]; p < 0.001, DLM8-M1 week four: 0 mm versus 326.1 ± 72.8 mm, mean difference 326.1 mm [95% CI 121.2 to 531]; p = 0.009), but modestly reduced local tumor growth in SaOS-2 (9.5 x 10 ± 8.3x10 photons/s versus 9.3 x 10 ± 1.5 x 10 photons/s, mean difference 8.6 x 10 photons/s [95% CI 5.1 x 10 to 1.2 x 10]; p < 0.001). Application of exogenous rhBMP-2 also increased 143b local tumor volume (495 ± 91.9 mm versus 1335 ± 102.7 mm, mean difference 840.3 mm [95% CI 671.7 to 1009]; p < 0.001). Incidence of lung metastases was not different between experimental or control groups for all experimental conditions. CONCLUSIONS: As demonstrated by others, ectopic BMP-2 signaling has unpredictable effects on local tumor proliferation in murine models of osteosarcoma and does not consistently result in osteosarcoma cell line differentiation. Further investigations into other methods of safe bone and soft tissue healing augmentation and the use of differentiation therapies is warranted. CLINICAL RELEVANCE: Our results indicate that BMP-2 has the potential to stimulate the growth of osteosarcoma cells that are poorly responsive to BMP-2 mediated osteoblastic differentiation. As this differentiation potential is unpredictable in the clinical setting, BMP-2 may promote the growth of microscopic residual tumor burden after resection. Our study provides further support for the recommendation to avoid the use of BMP-2 after limb-salvage surgery in patients with osteosarcoma.

Acute Disseminated Intravascular Coagulation After Prophylactic Nailing of the Femur in a Patient with Metastatic Prostate Cancer: A Case Report.

CASE: We present a case of acute disseminated intravascular coagulation (DIC) after prophylactic femoral intramedullary stabilization in a patient with metastatic prostate cancer. Preoperative international normalized ratio of 1.4 was attributed to malnutrition, and the patient was not medically optimized. DIC developed 1 hour postoperatively and was managed with blood product resuscitation. At the 4-month follow-up, the patient presented with bilateral pulmonary emboli and was transitioned to palliative care. CONCLUSIONS: DIC after intramedullary stabilization in patients with metastatic bone disease is a rare condition with high mortality rate. Early recognition, blood product resuscitation, and involvement of appropriate subspecialty services are imperative in DIC management.

VIS-IT: Visualizing the Injured Tibia-A Cadaveric Study of Limb Positioning for Posterolateral Tibial Plateau Fracture Visualization.

Posterolateral tibial plateau (PLTP) fractures are often associated with anterior cruciate ligament (ACL) incompetence, such as tibial eminence fractures. Both occur from a pivot shift like mechanism. Malreductions of the tibial plateau most frequently occur in the posterolateral quadrant. Acquiring adequate intraoperative visualization of the PLTP poses a challenge. We hypothesized that visualization of PLTP could be improved by positioning the knee at 110 degrees of flexion with the addition of a varus anterolateral rotatory vector. This position and maneuver take advantage of both the nonisometric nature of the lateral soft tissues and, when present, ACL incompetence. In this cadaveric study, we digitally quantified the percentage of the lateral tibial plateau visualized under different conditions after performing an anterolateral surgical approach with submeniscal arthrotomy. Four conditions were assessed for articular visualization: (1) 30 degrees of knee flexion, (2) 110 degrees of knee flexion, (3) 110-degrees of knee flexion plus varus anterolateral rotatory vector, (4) 110-degrees of knee flexion plus varus anterolateral rotatory vector with ACL sacrifice (ACL incompetence model). In the ACL competent models, maximal lateral tibial plateau exposure was obtained with the knee positioned at 110 degrees of flexion with a varus anterolateral rotatory vector (58.2%, range: 52.9-63.4%). Articular visualization was further improved with the ACL incompetent model (82.4%, range: 77.1-87.7%), modeling a tibial eminence fracture.