Enhancing radiotherapy response via intratumoral injection of the TLR9 agonist CpG to stimulate CD8 T cells in an autochthonous mouse model of sarcoma

Radiation therapy is frequently used to treat cancers including soft tissue sarcomas. Prior studies established that the toll-like receptor 9 (TLR9) agonist cytosine-phosphate-guanine oligodeoxynucleotide (CpG) enhances the response to radiation therapy (RT) in transplanted tumors, but the mechanism(s) remain unclear. Here, we used CRISPR/Cas9 and the chemical carcinogen 3-methylcholanthrene (MCA) to generate autochthonous soft tissue sarcomas with high tumor mutation burden. Treatment with a single fraction of 20 Gy RT and two doses of CpG significantly enhanced tumor response, which was abrogated by genetic or immunodepletion of CD8+ T cells. To characterize the immune response to RT + CpG, we performed bulk RNA-seq, single-cell RNA-seq, and mass cytometry. Sarcomas treated with 20 Gy and CpG demonstrated increased CD8 T cells expressing markers associated with activation and proliferation, such as Granzyme B, Ki-67, and interferon-γ. CpG + RT also upregulated antigen presentation pathways on myeloid cells. Furthermore, in sarcomas treated with CpG + RT, TCR clonality analysis suggests an increase in clonal T-cell dominance. Collectively, these findings demonstrate that RT + CpG significantly delays tumor growth in a CD8 T cell-dependent manner. These results provide a strong rationale for clinical trials evaluating CpG or other TLR9 agonists with RT in patients with soft tissue sarcoma.

Limb Amputations in Cancer: Modern Perspectives, Outcomes, and Alternatives

PURPOSE OF REVIEW

This review summarizes current findings regarding limb amputation within the context of cancer, especially in osteosarcomas and other bony malignancies. We seek to answer the question of how amputation is utilized in the contemporary management of cancer as well as explore current advances in limb-sparing techniques.

RECENT FINDINGS

The latest research on amputation has been sparse given its extensive history and application. However, new research has shown that rotationplasty, osseointegration, targeted muscle reinnervation (TMR), and regenerative peripheral nerve interfaces (RPNI) can provide patients with better functional outcomes than traditional amputation. While limb-sparing surgeries are the mainstay for managing musculoskeletal malignancies, limb amputation is useful as a palliative technique or as a primary treatment modality for more complex cancers. Currently, rotationplasty and osseointegration have been valuable limb-sparing techniques with osseointegration continuing to develop in recent years. TMR and RPNI have also been of interest in the modern management of patients requiring full or partial amputations, allowing for better control over myoelectric prostheses.

Regional anesthesia is associated with improved metastasis free survival after surgical resection of bone sarcomas

There is increasing evidence that perioperative factors, including type of anesthesia, may be an important consideration regarding oncological disease progression. Previous studies have suggested that regional anesthesia can improve oncological outcomes by reducing the surgical stress response that occurs during tumor resection surgery and that may promote metastatic progression. The purpose of this study is to provide the first robust investigation of the impact of adding regional anesthesia to general anesthesia on oncological outcomes following sarcoma resection. One hundred patients with bone sarcoma were retrospectively analyzed in this study. After adjusting for confounding variables such as age and grade of the tumor, patients with bone sarcoma receiving regional anesthesia in addition to general anesthesia during resection had improved metastasis free survival (multivariate hazard ratio of 0.47 and p = 0.034). Future studies are needed to confer the beneficial effect of regional anesthesia, and to further investigate the potential mechanism. Clinical significance: The results from this study provide evidence that regional anesthesia may be advantageous in the setting of bone sarcoma resection surgery, reducing pain while also improving oncological outcomes and should be considered when clinically appropriate.

Open Versus Core Needle Biopsy in Lower-Extremity Sarcoma: Current Practice Patterns and Patient Outcomes

BACKGROUND

Historically, open biopsy (OB) was the gold standard for sarcoma diagnosis. Core needle biopsy (CNB) has become increasingly common. There are limited data evaluating how the type of biopsy impacts definitive surgical resection or postoperative outcomes. The aims of this study were to (1) characterize current international biopsy practice patterns, and (2) evaluate how the type of biopsy performed impacts the resection surgery, infection risk, oncological complications, and patient-reported functional outcome scores.

METHODS

This study was a preplanned secondary analysis of the prospective, multicenter PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) study. Patients with a benign diagnosis, metastatic disease, or no biopsy prior to surgery were excluded. Prospectively collected demographic, biopsy, surgical, and outcome variables were analyzed, and differences between patients undergoing OB and CNB were assessed. Parametric and nonparametric tests were used to compare variables between groups, and the Cox proportional hazards method was used to compare infection-related and oncological outcomes at 1 year. Median functional outcome scores at 1 year were compared.

RESULTS

Four hundred and sixty-four patients met the inclusion criteria. Data were collected from 48 sarcoma centers in 12 countries. CNB was the more utilized biopsy modality overall (57.5%). OB was more common in the U.S. and Canada. The median operative time was significantly longer for patients who underwent OB (324 versus 260 minutes; p < 0.001). Significantly more skin (p < 0.001) and fascial tissue (p < 0.001) were excised in the OB group, which also had a lower rate of primary closure (86.3% versus 92.9%; p = 0.03). There were no differences in surgical site infection or oncological outcomes between the groups at 1-year follow-up.

CONCLUSIONS

CNB was the more common biopsy modality in the PARITY study in most countries. However, OB was more common in the U.S. and Canada. Patients undergoing OB had longer operative times, more excised tissue, and lower rates of primary closure, but this did not translate to differences in infection rates or oncological outcomes, including local recurrence.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Atrx deletion impairs CGAS/STING signaling and increases sarcoma response to radiation and oncolytic herpesvirus

ATRX is one of the most frequently altered genes in solid tumors, and mutation is especially frequent in soft tissue sarcomas. However, the role of ATRX in tumor development and response to cancer therapies remains poorly understood. Here, we developed a primary mouse model of soft tissue sarcoma and showed that Atrx-deleted tumors were more sensitive to radiation therapy and to oncolytic herpesvirus. In the absence of Atrx, irradiated sarcomas had increased persistent DNA damage, telomere dysfunction, and mitotic catastrophe. Our work also showed that Atrx deletion resulted in downregulation of the CGAS/STING signaling pathway at multiple points in the pathway and was not driven by mutations or transcriptional downregulation of the CGAS/STING pathway components. We found that both human and mouse models of Atrx-deleted sarcoma had a reduced adaptive immune response, markedly impaired CGAS/STING signaling, and increased sensitivity to TVEC, an oncolytic herpesvirus that is currently FDA approved for the treatment of aggressive melanomas. Translation of these results to patients with ATRX-mutant cancers could enable genomically guided cancer therapy approaches to improve patient outcomes.

Is a radiological score able to predict resection-grade chondrosarcoma in primary intraosseous lesions of the long bones?

Aims

The preoperative grading of chondrosarcomas of bone that accurately predicts surgical management is difficult for surgeons, radiologists, and pathologists. There are often discrepancies in grade between the initial biopsy and the final histology. Recent advances in the use of imaging methods have shown promise in the ability to predict the final grade. The most important clinical distinction is between grade 1 chondrosarcomas, which are amenable to curettage, and resection-grade chondrosarcomas (grade 2 and 3) which require en bloc resection. The aim of this study was to evaluate the use of a Radiological Aggressiveness Score (RAS) to predict the grade of primary chondrosarcomas in long bones and thus to guide management.

Methods

A total of 113 patients with a primary chondrosarcoma of a long bone presenting between January 2001 and December 2021 were identified on retrospective review of a single oncology centre's prospectively collected database. The nine-parameter RAS included variables from radiographs and MRI scans. The best cut-off of parameters to predict the final grade of chondrosarcoma after resection was determined using a receiver operating characteristic curve (ROC), and this was correlated with the biopsy grade.

Results

A RAS of ≥ four parameters was 97.9% sensitive and 90.5% specific in predicting resection-grade chondrosarcoma based on a ROC cut-off derived using the Youden index. Cronbach's α of 0.897 was derived as the interclass correlation for scoring the lesions by four blinded reviewers who were surgeons. Concordance between resection-grade lesions predicted from the RAS and ROC cut-off with the final grade after resection was 96.46%. Concordance between the biopsy grade and the final grade was 63.8%. However, when the patients were analyzed based on surgical management, the initial biopsy was able to differentiate low-grade from resection-grade chondrosarcomas in 82.9% of biopsies.

Conclusion

These findings suggest that the RAS is an accurate method for guiding the surgical management of patients with these tumours, particularly when the initial biopsy results are discordant with the clinical presentation.

Tumor necrosis is an underappreciated histopathologic factor in the grading of chondrosarcoma

BACKGROUND

Cartilaginous neoplasms can be challenging to grade; there is a need to create an evidence-based rubric for grading. The goal of this study was to identify histopathologic features of chondrosarcoma that were associated with 5-year survival and to compare these to traditional patient, tumor and treatment variables.

METHODS

This was a retrospective review of all patients undergoing surgical resection of a primary chondrosarcoma with at least 2 years of follow up. All specimens were independently reviewed by two pathologists and histopathologic features scored. Univariate and multivariate analyses were performed utilizing Kaplan Meier and proportional hazards methods to identify variables associated with 5-year disease specific survival (DSS) and disease free survival (DFS).

RESULTS

We identified 51 patients with an average follow up of 49 months eligible for inclusion. 30% of tumors were low grade, 45% were intermediate grade, and 25% were high grade. In a univariate analysis considering histopathologic factors, higher tumor mitotic rate (HR 8.9, p < 0.001), tumor dedifferentiation (HR 7.3, p < 0.001), increased tumor cellularity (HR 5.8, p = 0.001), increased tumor atypia (HR 5.8, p = 0.001), LVI (HR 4.7, p = 0.04) and higher tumor necrosis (HR 3.7, p = 0.02) were all associated with worse 5-year DSS. In a multivariate analysis controlling for potentially confounding variables, higher tumor necrosis was significantly associated with disease specific survival survival (HR 3.58, p = 0.035); none of the factors were associated with DFS.

CONCLUSIONS

This study provides an evidence-based means for considering histopathologic markers and their association with prognosis in chondrosarcoma. Our findings suggest that necrosis and LVI warrant further study.

Reconstructive Allograft Preparation for Long Bone Intercalary Segments After Tumor Resections: Toronto Sarcoma Protocol

Background

The Reconstructive Allograft Preparation by Toronto Sarcoma (RAPTORS) protocol is reliable and reproducible without substantially adding to the surgical reconstruction time or cost. Our technique includes clearance of debris, lavage of the medullary canal, pressurized filling of the medullary canal with antibiotic-laden cement for its mechanical and antimicrobial properties, and insertion of cancellous autograft at the allograft-host junctional ends prior to dual-plate compression to fix the allograft into the defect1-3. Our experience with large intercalary allograft reconstruction has demonstrated high rates of long-term success and addresses the most common causes of large allograft failure (infection, fracture, and nonunion)4, as shown in our long-term outcome study1.

Description

Once the tumor is resected, it is used as a template for cutting and shaping the allograft to fit the bone defect and to restore length and anatomy. The frozen allograft is thawed in a container with povidone iodine and bacitracin saline solution until it reaches room temperature. The allograft is size-matched, and clearance of its intramedullary marrow contents is performed with use of curets and intramedullary reamers7. If 1 end of the allograft includes the metaphysis and is covered by dense cancellous bone, we try not to ream through this end because maintaining this metaphyseal cancellous surface will expedite bone healing. The segment is then thoroughly lavaged with "triple wash" solutions to clear out any remaining marrow contents and to ensure sterilization of the allograft. This serial-wash technique involves the use of 3 discrete antiseptic modalities and has been utilized at our institution with low rates of allograft infection. These antiseptic modalities include 10% weight-per-volume povidone iodine diluted 1:1 with normal saline solution, 3% weight-per-volume hydrogen peroxide diluted 1:1 with normal saline solution, and 50,000 units of sterile bacitracin lyophilized powder dissolved in 500 mL of normal saline solution. Following the triple wash, the medullary canal is filled with antibiotic-laden methylmethacrylate bone cement. If both ends are open, the far end of the segment is first plugged with the surgeon's finger or with gauze, or if 1 end is covered with cancellous bone, then retrograde filling of the canal with cement is performed from the open end. The cement is then pressurized to ensure complete filling of the intramedullary space. Before it sets, 1 cm of cement is removed from each open end of the allograft to allow for packing of autograft bone cancellous chips and to ensure that cement does not impede anatomic reduction of the allograft-host bone junction. For this step, cancellous autograft from the iliac crest is harvested with use of a separate sterile surgical setup in order to prevent contamination of the autograft site by instruments used for tumor resection. The cancellous autograft is packed into the space created after recessing the cement at the end(s) of the allograft and, using a bone tamp, the autograft is compressed into this cavity and into the corresponding end of the host long bone in order to improve the healing potential at the allograft-host bone junction(s)8. Finally, a dual compression plate construct is utilized for upper as well as lower-extremity reconstructions in most cases. The cement in the allograft must be completely hardened before drilling into it. The allograft-host bone junctions are sequentially compressed at both the proximal and distal ends to allow for maximal apposition of the osseous surfaces. Only 1 or 2 unicortical screws are placed into the allograft to hold it in place and to facilitate maximal compression at both bone junctions. Patient compliance during postoperative rehabilitation is essential to optimize healing and provide reliable and durable outcomes. Postoperative care following the RAPTORS technique includes limited early rehabilitation and long periods of non-weight-bearing until radiographic union is noted across both bone junctions, followed by gradual resumption of weight-bearing and more aggressive physiotherapy. See the Appendix for further details regarding each step of the procedure.

Alternatives

Intercalary reconstruction alternatives include various biological or endoprosthetic constructs. The other biological reconstruction options include the use of a free vascularized bone graft, distraction osteogenesis, combined vascularized fibula and allograft (i.e., the Capanna technique), or recycled tumor bones. Intercalary prostheses offer another reconstruction option for diaphyseal defects, but their feasibility is more limited in cases of periarticular segments with very short residual medullary canals. In such cases, there may be inadequate stem length for fixation, or the segment may require a custom implant that takes time to design and manufacture, which can be associated with high costs5.

Rationale

Major factors limiting the widespread use of allografts include infection, graft fracture, graft nonunion, and, in some locations, availability4,6. Our technique of allograft preparation with dual compression plating and triple-washing to provide mechanical and antimicrobial protection as well as augmented healing has shown reproducible results with low complication rates compared with the literature.

Expected Outcomes

There have been high rates of long-term allograft survival (84.4%) following intercalary long-bone reconstruction at our institution, with lower complication rates than those presented in the literature.

Important Tips

Transverse osteotomies of the allograft, made perpendicular to the long axis of the diaphysis/anatomical axis, are important to replicate the resected host bone. Transverse osteotomies, while inherently less stable than step-cut ones, allow for adjusting the rotation of the allograft segment as needed for maximal contact and compression, as well as restoration of anatomical limb rotation.It is important to perform meticulous clearance of the intramedullary contents while preserving the endosteal bone and allograft integrity. We would utilize hand-reaming rather than a power drill device, in order to prevent overreaming or breaking through the allograft bone.Place as few unicortical screws as possible into the allograft-cement construct in order to maintain its structural strength and minimize potential sites for vascular ingrowth and bone resorption.

Acronyms & Abbreviations

K-wires = Kirschner wiresW/V = weight per volume.

Intraoperative angiography imaging correlates with wound complications following soft tissue sarcoma resection

For soft tissue sarcoma patients receiving preoperative radiation therapy, wound complications are common and potentially devastating. The purpose of this study was to assess the feasibility of intraoperative indocyanine green fluorescent angiography (ICGA) as a predictor of wound complications in these patients. A consecutive series of patients with soft tissue sarcoma of the extremities or pelvis who received neoadjuvant radiation and a subsequent radical resection received intraoperative ICGA with the SPY PHI device (Stryker Inc.) at the time of closure. Retrospective analysis of fluorescence signal along multiple points of the wound length was performed and quantified. The primary endpoint was wound complication, defined as delayed wound healing or wound dehiscence, within 3 months of surgery. Fourteen patients with preoperative irradiated soft tissue sarcoma were consecutively imaged. There were six patients with wound complications classified as "aseptic" in five cases. Using the ICGA, blinded surgeons correctly predicted wound complications in 75% of cases. During the inflow phase, a mean ratio of normal of 0.62 maximized the area under the curve (AUC = 0.90) for predicting wound complications with a sensitivity of 100% and specificity of 77.4%. During the peak phase, a mean ratio of normal of 0.55 maximized the AUC (0.95) for predicting wound complications with a sensitivity of 88.9% and a specificity of 100%. Intraoperative use of ICGA may help to predict wound complications in patients undergoing resection of preoperatively irradiated soft tissue sarcomas of the extremities and pelvis.

Abstract 1061: Exportin 1 (XPO1) inhibition alone or in combination as a novel therapeutic strategy in osteosarcoma

Background: Osteosarcoma is an aggressive bone cancer in which therapeutic advancements have been limited over the last 30 years, in part due to genomic heterogeneity. The combination of high-throughput drug screening platforms that efficiently pinpoint drug sensitivities with patient-derived cross-species models is an innovative approach to address the critical need to identify novel treatment strategies for osteosarcoma patients.

Methods: We performed high-throughput drug screens on patient-derived osteosarcoma cell lines D418 (canine) and 17-3x (human), followed by validation of the top compounds, to identify drug sensitivities and novel therapeutic combinations.

Results: High-throughput drug screens using 2100 bioactive compounds show that osteosarcoma cell lines D418 and 17-3x exhibited sensitivity to standard-of-care chemotherapy drugs, inhibitors of XPO1 nuclear export, and proteasome inhibitors. The XPO1 inhibitor, verdinexor (VER), and the proteasome inhibitor, bortezomib (BORT), induced dose-dependent cytotoxicity in multiple osteosarcoma cell lines (D418, IC50VER: 3187 nM, IC50BORT: 2.8 nM; 17-3x IC50VER: 679 nM, IC50BORT: 10.9 nM). In addition, dual XPO1 and proteasome inhibition synergistically reduced cell proliferation in D418 (synergy score=12.89) and 17-3x (synergy score=17.87) cell lines (p &lt;0.05). Selinexor (SEL), an FDA approved XPO1 inhibitor used in combination with bortezomib to treat multiple myeloma, also demonstrated dose-dependent single-agent activity in patient-derived osteosarcoma cell lines (D418, IC50SEL: 370 nM; 17-3x IC50SEL: 101 nM). With drug screening of 119 oncology compounds in combination with selinexor in 17-3x cells, XPO1 inhibition again shows synergistic activity with proteasome inhibition in osteosarcoma.

Conclusions: Inhibition of XPO1-mediated nuclear export is a promising therapeutic strategy in osteosarcoma. These effects may be further potentiated when used in combination with other agents, such as proteasome inhibitors. Additional drug screening and validation assays are underway to identify novel synergistic agents for use in combination with XPO1 inhibitors in osteosarcoma.

Citation Format: Laurie Graves, Gabrielle Rupprecht, Erdem Altunel, Etienne M. Flamant, Sneha Rao, Dharshan Sivara, Alexander L. Lazarides, Sarah M. Hoskinson, Maya U. Sheth, Serene Cheng, So Young Kim, Kathryn E. Ware, Anika Agarwal, Mark M. Cullen, Casey Syal, Laura E. Selmic, Jeffrey I. Everitt, Shannon J. McCall, Cindy Eward, Trinayan Kashyap, Marie Maloof, Christopher J. Walker, Yosef Landesman, Lars Wagner, William C. Eward, David S. Hsu, Jason A. Somarelli. Exportin 1 (XPO1) inhibition alone or in combination as a novel therapeutic strategy in osteosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1061.

Is Advanced Imaging to Assess Rotator Cuff Integrity Before Shoulder Arthroplasty Cost-effective? A Decision Modeling Study

BACKGROUND

Shoulder arthroplasty is increasingly performed for patients with symptoms of glenohumeral arthritis. Advanced imaging may be used to assess the integrity of the rotator cuff preoperatively because a deficient rotator cuff may be an indication for reverse shoulder arthroplasty (RSA) rather than anatomic total shoulder arthroplasty (TSA). However, the cost-effectiveness of advanced imaging in this setting has not been analyzed.

QUESTIONS/PURPOSES

In this cost-effectiveness modeling study of TSA, all patients underwent history and physical examination, radiography, and CT, and we compared (1) no further advanced imaging, (2) selective MRI, (3) MRI for all, (4) selective ultrasound, and (5) ultrasound for all.

METHODS

A simple chain decision model was constructed with a base-case 65-year-old patient with a 7% probability of a large-to-massive rotator cuff tear and a follow-up of 5 years. Strategies were compared using the incremental cost-effectiveness ratio (ICER) with a willingness to pay of both USD 50,000 and 100,000 per quality-adjusted life year (QALY) used, in accordance with the Second Panel on Cost-Effectiveness in Health and Medicine. Diagnostic test sensitivity and specificity were extracted from published systematic reviews and meta-analyses, and patient utilities were obtained using the Cost-Effectiveness Analysis Registry from the Center for the Evaluation of Value and Risk in Health. Final patient states were categorized as either inappropriate or appropriate based on the actual rotator cuff integrity and type of arthroplasty performed. Additionally, to evaluate the real-world impact of intraoperative determination of rotator cuff status, a secondary analysis was performed where all patients indicated for TSA underwent intraoperative rotator cuff examination to determine appropriate implant selection.

RESULTS

Selective MRI (ICER of USD 40,964) and MRI for all (ICER of USD 79,182/QALY) were the most cost-effective advanced imaging strategies at a willingness to pay (WTP) of USD 50,000/QALY gained and 100,000/QALY gained, respectively. Overall, quality-adjusted life years gained by advanced soft tissue imaging were minimal: 0.04 quality-adjusted life years gained for MRI for all. Secondary analysis accounting for the ability of the surgeon to alter the treatment plan based on intraoperative rotator cuff evaluation resulted in the no further advanced imaging strategy as the dominant strategy as it was the least costly (USD 23,038 ± 2259) and achieved the greatest health utility (0.99 ± 0.05). The sensitivity analysis found the original model was the most sensitive to the probability of a rotator cuff tear in the population, with the value of advanced imaging increasing as the prevalence increased (rotator cuff tear prevalence greater than 12% makes MRI for all cost-effective at a WTP of USD 50,000/QALY).

CONCLUSION

In the case of diagnostic ambiguity based on physical exam, radiographs, and CT alone, having both TSA and RSA available in the operating room appears more cost-effective than obtaining advanced soft tissue imaging preoperatively. However, performing selective MRI to assess rotator cuff integrity to indicate RSA or TSA is cost-effective if surgical preparedness, patient expectations, and implant availability preclude the ability to switch implants intraoperatively.

LEVEL OF EVIDENCE

Level III, economic and decision analysis.

How Do the Outcomes of Radiation-Associated Pelvic and Sacral Bone Sarcomas Compare to Primary Osteosarcomas following Surgical Resection?

Radiation-associated sarcoma of the pelvis and/or sacrum (RASB) is a rare but challenging disease process associated with a poor prognosis. We hypothesized that patients with RASB would have worse surgical and oncologic outcomes than patients diagnosed with primary pelvic or sacral bone sarcomas. This was a retrospective, multi-institution, comparative analysis. We reviewed surgically treated patients from multiple tertiary care centers who were diagnosed with a localized RASB. We also identified a comparison group including all patients diagnosed with a primary localized pelvic or sacral osteosarcoma/spindle cell sarcoma of bone (POPS). There were 35 patients with localized RASB and 73 patients with POPS treated with surgical resection. Patients with RASB were older than those with POPS (57 years vs. 38 years, p < 0.001). Patients with RASB were less likely to receive chemotherapy (71% for RASB vs. 90% for POPS, p = 0.01). Seventeen percent of patients with RASB died in the perioperative period (within 90 days of surgery) as compared to 4% with POPS (p = 0.03). Five-year disease-specific survival (DSS) (31% vs. 54% p = 0.02) was worse for patients with RASB vs. POPS. There was no difference in 5-year local recurrence free survival (LRFS) or metastasis free survival (MFS). RASB and POPS present challenging disease processes with poor oncologic outcomes. Rates of perioperative mortality and 5-year DSS are worse for RASB when compared to POPS.

Investigating readmission rates for patients undergoing oncologic resection and endoprosthetic reconstruction for primary sarcomas and tumors involving bone

BACKGROUND

Little is known about the drivers of readmission in patients undergoing Orthopaedic oncologic resection. The goal of this study was to identify factors independently associated with 90-day readmission for patients undergoing oncologic resection and subsequent prosthetic reconstruction for primary tumors involving bone.

METHODS

This was a retrospective comparative cohort study of patients treated from 2008 to 2019 who underwent endoprosthetic reconstruction for a primary bone tumor or soft tissue tumor involving bone, as well as those who underwent a revision endoprosthetic reconstruction if the primary endoprosthetic reconstruction was performed for an oncologic resection. The primary outcome measure was unplanned 90-day readmission.

RESULTS

A total of 149 patients were identified who underwent 191 surgeries were for a primary bone or soft tissue tumor. The 90-day readmission rate was 28.3%. Female gender, depression, higher tumor grade, vascular reconstruction, longer procedure duration, longer length of stay (LOS), multiple surgeries during an admission and disposition to a Skilled Nursing Facility were associated with readmission (p < 0.05). In a multivariate analysis, female sex, higher tumor grade and longer procedure duration were independently associated with risk of readmission (p < 0.05).

CONCLUSIONS

Readmission rates are high following endoprosthetic reconstruction for Orthopaedic oncologic resections. Further work is necessary to help minimize unplanned readmissions.

Why Do Patients Undergoing Extremity Prosthetic Reconstruction for Metastatic Disease Get Readmitted?

BACKGROUND

Orthopedic oncology patients are particularly susceptible to increased readmission rates and poor surgical outcomes, yet little is known about readmission rates. The goal of this study is to identify factors independently associated with 90-day readmission for patients undergoing oncologic resection and subsequent prosthetic reconstruction for metastatic disease of the hip and knee.

METHODS

This is a retrospective comparative cohort study of all patients treated from 2013 to 2019 at a single tertiary care referral institution who underwent endoprosthetic reconstruction by an orthopedic oncologist for metastatic disease of the extremities. The primary outcome measure was unplanned 90-day readmission.

RESULTS

We identified 112 patients undergoing 127 endoprosthetic reconstruction surgeries. Metastatic disease was most commonly from renal (26.8%), lung (23.6%), and breast (13.4%) cancer. The most common type of skeletal reconstruction performed was simple arthroplasty (54%). There were 43 readmissions overall (33.9%). When controlling for confounding factors, body mass index >40, insurance status, peripheral vascular disease, and longer hospital length of stay were independently associated with risk of readmission (P ≤ .05).

CONCLUSION

Readmission rates for endoprosthetic reconstructions for metastatic disease are high. Although predicting readmission remains challenging, risk stratification presents a viable option for helping minimize unplanned readmissions.

LEVEL OF EVIDENCE

III.

Extent of tumor fibrosis/hyalinization and infarction following neoadjuvant radiation therapy is associated with improved survival in patients with soft-tissue sarcoma

Introduction

Current standard of care for most intermediate and high‐grade soft‐tissue sarcomas (STS) includes limb‐preserving surgical resection with either neoadjuvant radiation therapy (NRT) or adjuvant radiation therapy. To date, there have been a few studies that attempt to correlate histopathologic response to NRT with oncologic outcomes in patients with STS.

Methods

Using our institutional database, we identified 58 patients who received NRT followed by surgical resection for primary intermediate or high‐grade STS and 34 patients who received surgical resection without NRT but did receive adjuvant radiation therapy or did not receive any radiation therapy. We analyzed four histologic parameters of response to therapy: residual viable tumor, fibrosis/hyalinization, necrosis, and infarction (each ratiometrically determined). Data were stratified into two binary groups. Unadjusted, 5‐ and 10‐year overall survival, and relapsed‐free survival (RFS) were calculated using the Kaplan–Meier method.

Results

Analysis of pathologic characteristics showed that patients treated with NRT demonstrate significantly higher tumor infarction, higher tumor fibrosis/hyalinization, and a lower percent viable tumor compared with patients not treated with NRT (p < 0.0001). Based on Kaplan–Meier curve analysis and multivariate cox proportional hazard model for OS and RFS, patients treated with NRT and showing >12.5% tumor fibrosis/hyalinization have significantly higher overall survival and recurrence‐free survival at 5 and 10 years.

Discussion and Conclusion

We have identified three histopathologic characteristics—fibrosis, hyalinization, and infarction—that may serve as predictive biomarkers of response to NRT for STS patients. Future prospective studies will be needed to confirm this association.

Reverse total shoulder arthroplasty for oncologic reconstruction of the proximal humerus: a systematic review

BACKGROUND

In recent years, there has been growing interest in the use of reverse total shoulder arthroplasty (rTSA) for reconstruction of the proximal humerus after oncologic resection. However, the indications and outcomes of oncologic rTSA remain unclear.

METHODS

We conducted a systematic review to identify studies that reported outcomes of patients who underwent rTSA for oncologic reconstruction of the proximal humerus. Extracted data included demographic characteristics, indications, operative techniques, outcomes, and complications. Weighted means were calculated according to sample size.

RESULTS

Twelve studies were included, containing 194 patients who underwent rTSA for oncologic reconstruction of the proximal humerus. The mean patient age was 48 years, and 52% of patients were male. Primary malignancies were present in 55% of patients; metastatic disease, 30%; and benign tumors, 9%. The mean humeral resection length was 12 cm. The mean postoperative Musculoskeletal Tumor Society score was 78%; Constant score, 60; and Toronto Extremity Salvage Score, 77%. The mean complication rate was 28%, with shoulder instability accounting for 63% of complications. Revisions were performed in 16% of patients, and the mean implant survival rate was 89% at a mean follow-up across studies of 53 months.

CONCLUSIONS

Although the existing literature is of poor study quality, with a high level of heterogeneity and risk of bias, rTSA appears to be a suitable option in appropriately selected patients undergoing oncologic resection and reconstruction of the proximal humerus. The most common complication is instability. Higher-quality evidence is needed to help guide decision making on appropriate implant utilization for patients undergoing oncologic resection of the proximal humerus.

Identifying Modifiable and Non-modifiable Risk Factors of Readmission and Short-Term Mortality in Chondrosarcoma: A National Cancer Database Study

BACKGROUND

Limited data are available to inform the risk of readmission and short-term mortality in musculoskeletal oncology. The goal of this study was to identify factors independently associated with 30-day readmission and 90-day mortality following surgical resection of chondrosarcoma.

METHODS

We retrospectively reviewed 6653 patients following surgical resection of primary chondrosarcoma in the National Cancer Database (2004-2017). Both demographic and clinicopathologic variables were assessed for correlation with readmission and short-term mortality utilizing univariate and multivariate logistic regression modeling.

RESULTS

Of 220 readmissions (3.26%), risk factors independently associated with an increased risk of unplanned 30-day readmission included Charlson-Deyo Comorbidity Index (CDCC) (odds ratio [OR] 1.31; p = 0.027), increasing American Joint Committee on Cancer (AJCC) stage (OR 1.31; p = 0.004), undergoing major amputation (OR 2.38; p = 0.001), and axial skeletal location (OR 1.51; p = 0.028). A total of 137 patients died within 90 days of surgery (2.25%). Risk factors associated with increased mortality included the CDCC (OR 1.60; p = 0.001), increasing age (OR 1.06; p < 0.001), having Medicaid insurance status (OR 3.453; p = 0.005), living in a zip code with a higher educational attainment (OR 1.59; p = 0.003), increasing AJCC stage (OR 2.32; p < 0.001), longer postoperative length of stay (OR 1.015; p = 0.033), and positive surgical margins (OR 2.75; p = 0.001). Although a majority of the cohort did not receive radiation therapy (88.8%), receiving radiotherapy (OR 0.132; p = 0.010) was associated with a decreased risk of short-term mortality.

CONCLUSIONS

Several tumor, treatment, and patient factors can help inform the risk of readmission and short-term mortality in patients with surgically treated chondrosarcoma.

Physician burnout and professional satisfaction in orthopedic surgeons during the COVID-19 Pandemic

BACKGROUND

Burnout and professional satisfaction is an often an overlooked component for healthcare outcomes; the COVID-19 pandemic represents an unprecedented stressor that could contribute to higher levels of burnout.

OBJECTIVES

Our primary objective was to evaluate the association of a battery of fulfillment, job satisfaction change, COVID-19 concerns, and coping measures. Our secondary objective was to determine whether the fulfillment and coping measures differed by gender and by experience levels among a battery of physician specialties.

METHODS

The study was a purposive sample of convenience. Study participants included all trainees and attending orthopedic surgeons from our academic institution; all participants were invited to complete a survey built around a validated measure of professional fulfillment aimed at assessing response to acute change and stressors. We performed univariate statistics and a matrix correlational analysis to correlate different survey domains with variables of interest.

RESULTS

The survey was sent electronically to 138 individuals; 63 surveys were completed (response rate = 45.7%). Twenty-seven (42.8%) individuals met the threshold criteria for fulfillment whereas 10 (15.9%) met the threshold for burnout. We found that surgeon perspectives on COVID-19 were not associated with burnout or professional fulfillment. Burnout was inversely associated with professional fulfillment (R = -0.35). Support seeking was noted to be correlated with professional fulfillment (R = 0.37).

CONCLUSIONS

Stressors related to COVID-19 pandemic were not correlated with physician burnout and fulfillment. This held true even when stratifying by gender and by attending vs. trainee. Continued efforts should be implemented to protect against physician burnout and ensure professional fulfillment for Orthopedic surgeons.

Identifying Modifiable and Non-modifiable Risk Factors of Readmission and Short-Term Mortality in Osteosarcoma: A National Cancer Database Study

BACKGROUND

There are limited data to inform risk of readmission and short-term mortality in musculoskeletal oncology. The goal of this study was to identify factors independently associated with 30-day readmission and 90-day mortality following surgical resection of osteosarcoma.

METHODS

We retrospectively reviewed patients (n = 5293) following surgical resection of primary osteosarcoma in the National Cancer Database (2004-2015). Univariate and multivariate methods were used to correlate variables with readmission and short-term mortality.

RESULTS

Of 210 readmissions (3.97%), risk factors independently associated with unplanned 30-day readmission included comorbidity burden (odds ratio [OR] 2.4, p = 0.042), Medicare insurance (OR 1.9, p = 0.021), and axial skeleton location (OR 1.5, p = 0.029). A total of 91 patients died within 90 days of their surgery (1.84%). Risk factors independently associated with mortality included age (hazard ratio 1.1, p < 0.001), increasing comorbidity burden (OR 6.6, p = 0.001), higher grade (OR 1.7, p = 0.007), increasing tumor size (OR 2.2, p = 0.03), metastatic disease at presentation (OR 8.5, p < 0.001), and amputation (OR 2.0, p = 0.04). Chemotherapy was associated with a decreased risk of short-term mortality (p < 0.001).

CONCLUSIONS

Several trends were clear: insurance status, tumor location and comorbidity burden were independently associated with readmission rates, while age, amputation, grade, tumor size, metastatic disease, and comorbidity burden were independently associated with short-term mortality.

Next-generation sequencing not superior to culture in periprosthetic joint infection diagnosis

AIMS

Use of molecular sequencing methods in periprosthetic joint infection (PJI) diagnosis and organism identification have gained popularity. Next-generation sequencing (NGS) is a potentially powerful tool that is now commercially available. The purpose of this study was to compare the diagnostic accuracy of NGS, polymerase chain reaction (PCR), conventional culture, the Musculoskeletal Infection Society (MSIS) criteria, and the recently proposed criteria by Parvizi et al in the diagnosis of PJI.

METHODS

In this retrospective study, aspirates or tissue samples were collected in 30 revision and 86 primary arthroplasties for routine diagnostic investigation for PJI and sent to the laboratory for NGS and PCR. Concordance along with statistical differences between diagnostic studies were calculated.

RESULTS

Using the MSIS criteria to diagnose PJI as the reference standard, the sensitivity and specificity of NGS were 60.9% and 89.9%, respectively, while culture resulted in sensitivity of 76.9% and specificity of 95.3%. PCR had a low sensitivity of 18.4%. There was no significant difference based on sample collection method (tissue swab or synovial fluid) (p = 0.760). There were 11 samples that were culture-positive and NGS-negative, of which eight met MSIS criteria for diagnosing infection.

CONCLUSION

In our series, NGS did not provide superior sensitivity or specificity results compared to culture. PCR has little utility as a standalone test for PJI diagnosis with a sensitivity of only 18.4%. Currently, several laboratory tests for PJI diagnosis should be obtained along with the overall clinical picture to help guide decision-making for PJI treatment. Cite this article: Bone Joint J 2021;103-B(1):26-31.

The Calpain Gene is Correlated With Metal-on-Metal Hip Replacement Failures

BACKGROUND

Metal-on-metal (MOM) total hip arthroplasty is associated with unacceptable failure rates secondary to metal ion reactions. Efforts to identify which patients will go on to failure have been limited; recently, there has been a suggestion for a potential genetic basis for the increased risk of revision in MOM hip replacements (MOMHRs). The purpose of this study is to determine whether certain immunologic genotypes are predictive of the need for revision in patients with MOM total hip implants.

METHODS

This is a case-control study of all patients undergoing primary MOMHR between September 2002 and January 2012 with a minimum of 5-year follow-up. Our investigational "case" cohort was comprised of patients who underwent revision for MOMHR for a reason other than infection. A single-nucleotide polymorphism (SNP) array analysis was performed to identify a potential genetic basis for failure.

RESULTS

Thirty-two patients (15 case and 17 control) were included in our analysis. All patients in the revision group had a chief complain of pain; revision patients were more likely to have a posterior approach (P = .01) and larger head size (P = .04) than nonrevision patients. No patient or implant characteristics were independently associated with revision in a multivariate analysis. Patients with SNP kgp9316441 were identified as having an increased odds of revision for MOM failure (P < .001).

CONCLUSION

This study identified an SNP, kgp9316441, encoding proteins associated with inflammation and macrophage activation. This SNP was associated with significantly increased odds of revision for MOMHR. Future studies are warranted to validate this gene target both in vitro and in vivo.

LEVEL OF EVIDENCE

III.

Tibiotalocalcaneal Arthrodesis Using a Novel Retrograde Intramedullary Nail

Background. Tibiotalocalcaneal (TTC) arthrodesis is a common treatment option for complex hindfoot pathology. Overall union rates range from 50% to 86% but can be even lower in certain populations. A novel retrograde intramedullary nail has recently been developed. The purpose of this study was to report fusion rates, time to weight-bearing, and complications with the use of the A3 Fusion Nail. Methods. All patients 18 years or older who underwent TTC arthrodesis with an A3 Fusion Nail at a single institution from 2010 to 2015 with a minimum 3-month follow-up were included in this study. Rates of successful fusion, time to union, time to weight-bearing, and complications were evaluated. A total of 20 patients with an average age of 58.1 years and an average follow-up of 12.5 months met inclusion criteria. Results. Successful TTC arthrodesis was achieved in 14 of 20 patients (70%) overall. Average time to union was 8.1 months, and average time to weight-bearing was 6.8 weeks. Of 20 patients, 17 (85%) required femoral head allograft for bulk bone defects, and the union rate in this subset of patients was 76.5%. The rates of revision surgery (10%) and complications were low. Conclusion. The A3 Fusion Nail demonstrated a favorable safety profile and achieved TTC arthrodesis at a rate consistent with historical data despite being used in a patient population at high risk for nonunion. In patients with bulk bone defects at high risk for nonunion, the A3 Fusion Nail demonstrated superior rates of fusion (76.5%) to those reported in the literature (50%).Level of Evidence: Level III: Retrospective cohort study.

A Comparative Oncology Drug Discovery Pipeline to Identify and Validate New Treatments for Osteosarcoma

Simple Summary

Osteosarcoma is a rare bone cancer that occurs primarily in children. The discovery of new treatments for osteosarcoma and other rare cancer types has been severely limited by access to patient samples to study these often-complex diseases. Here we capitalize on naturally-occurring cancers in pet dogs to study the biology of these rare cancers. Using living cells from canine and human patients to test thousands of drugs simultaneously, we identify a unique combination of drugs that disrupts protein degradation and protein trafficking in cancer cells. This drug combination represents a promising new treatment to treat both dogs and people with osteosarcoma.

Abstract

Background: Osteosarcoma is a rare but aggressive bone cancer that occurs primarily in children. Like other rare cancers, treatment advances for osteosarcoma have stagnated, with little improvement in survival for the past several decades. Developing new treatments has been hampered by extensive genomic heterogeneity and limited access to patient samples to study the biology of this complex disease. Methods: To overcome these barriers, we combined the power of comparative oncology with patient-derived models of cancer and high-throughput chemical screens in a cross-species drug discovery pipeline. Results: Coupling in vitro high-throughput drug screens on low-passage and established cell lines with in vivo validation in patient-derived xenografts we identify the proteasome and CRM1 nuclear export pathways as therapeutic sensitivities in osteosarcoma, with dual inhibition of these pathways inducing synergistic cytotoxicity. Conclusions: These collective efforts provide an experimental framework and set of new tools for osteosarcoma and other rare cancers to identify and study new therapeutic vulnerabilities.

Commercially Available Polymerase Chain Reaction Has Minimal Utility in the Diagnosis of Periprosthetic Joint Infection

The use of genetic sequencing modalities in the diagnosis of periprosthetic joint infection (PJI) and the identification of organisms has gained popularity recently. Polymerase chain reaction (PCR) offers timely results for common organisms. The purpose of this study was to compare the accuracy of broad-range PCR, conventional culture, the Musculoskeletal Infection Society (MSIS) criteria, and the recently proposed criteria by Parvizi et al in the diagnosis of PJI. In this retrospective study, aspirate or tissue samples were collected in 104 revision and 86 primary arthroplasties for routine diagnostic workup for PJI and sent to the laboratory for PCR. Concordance along with statistical differences between diagnostic studies were calculated using chi-square test for categorical data. On comparison with the MSIS criteria, concordance was significantly lower for PCR at 64.7% compared with 86.3% for culture (P<.001). There was no significant difference based on diagnosis of prior infection (P=.706) or sample collection method (tissue swab or synovial fluid) (P=.316). Of the 87 patients who met MSIS criteria, only 20 (23.0%) PCR samples had an organism identified. In this series, PCR had little utility as a stand-alone test for the diagnosis of PJI, with a sensitivity of only 23.0% when using MSIS criteria as the gold standard. Polymerase chain reaction also appears to be significantly less accurate than culture in the diagnosis of PJI. Currently, several laboratory tests used for either criteria for PJI diagnosis should be obtained along with the overall clinical picture to help guide decision-making for PJI treatment. [Orthopedics. 2020;43(6):333-338.].

Limb salvage versus amputation in patients with osteosarcoma of the extremities: an update in the modern era using the National Cancer Database

BACKGROUND

Historically, amputation was the primary surgical treatment for osteosarcoma of the extremities; however, with advancements in surgical techniques and chemotherapies limb salvage has replaced amputation as the dominant treatment paradigm. This study assessed the type of surgical resection chosen for osteosarcoma patients in the twenty-first century.

METHODS

Utilizing the largest registry of primary osteosarcoma, the National Cancer Database (NCDB), we retrospectively analyzed patients with high grade osteosarcoma of the extremities from 2004 through 2015. Differences between patients undergoing amputation and patients undergoing limb salvage are described. Unadjusted five-year overall survival between patients who received limb salvage and amputation was assessed utilizing Kaplan Meier curves. A multivariate Cox proportional hazard model and propensity matched analysis was used to determine the variables independently correlated with survival.

RESULTS

From a total of 2442 patients, 1855 underwent limb salvage and 587 underwent amputation. Patients undergoing amputation were more likely to be older, male, uninsured, and live in zip codes associated with lower income. Patients undergoing amputation were also more likely to have larger tumors, more comorbid conditions, and metastatic disease at presentation. After controlling for confounders, limb salvage was associated with a significant survival benefit over amputation (HR: 0.70; p < 0.001). Although this may well reflect underlying biases impacting choice of treatment, this survival benefit remained significant after propensity matched analysis of all significantly different independent variables (HR: 0.71; p < 0.01).

CONCLUSION

Among patients in the NCDB, amputation for osteosarcoma is associated with advanced age, advanced stage, larger tumors, greater comorbidities, and lower income. Limb salvage is associated with a significant survival benefit, even when controlling for significant confounding variables and differences between cohorts.

Defining a textbook surgical outcome for patients undergoing surgical resection of intermediate and high-grade soft tissue sarcomas of the extremities

BACKGROUND

Quality measures for the surgical management soft tissue sarcoma of the extremity are limited. The purpose of this study was to define a textbook surgical outcome (TO) for soft tissue sarcoma of the extremities (STS-E) and to examine its associations with hospital volume and overall survival.

METHODS

All patients in the National Cancer Database undergoing resection of primary STS-E between 2004 and 2015 were identified. The primary outcome was a TO, defined as: hospital length of stay (LOS) <75th percentile, survival >90 days from the date of surgery, no readmission within 30 days of discharge, and negative surgical margins (R0 resection).

RESULTS

Overall, 7658 patients met criteria for inclusion; a TO was achieved in 4291 (56%) patients. Of patients who did not achieve TOs, 51.9% (n = 1748) had an extended LOS, and 47.3% (n = 1591) did not have negative margins. Older age, more medical comorbidities, and non-white or black race were independently associated with not receiving a TO (P = .034). With respect to tumor and treatment characteristics, larger tumor size, lower extremity location and higher grade were independently associated with not receiving a TO (P < .001). Hospital volume was not associated with a TO. TOs conferred a significant survival benefit (hazrds ratio = 0.71 [0.65-0.78], P < .001). A TO was associated with a 27.5% longer survival time (P < .001).

CONCLUSIONS

This study defined a TO in intermediate and high-grade STS-E and demonstrated that this outcome measure is associated with overall survival. Facility volume was not associated with a TO.

Does facility volume influence survival in patients with primary malignant bone tumors of the vertebral column? A comparative cohort study

BACKGROUND CONTEXT

Facility volume has been correlated with survival in many cancers. This relationship has not been established in primary malignant bone tumors of the vertebral column (BTVC).

PURPOSE

To investigate whether facility patient volume is associated with overall survival in patients with primary malignant BTVCs.

STUDY DESIGN

Retrospective comparative cohort.

PATIENT SAMPLE

Adult patients with chordomas, chondrosarcomas, or osteosarcomas of the mobile spine.

OUTCOME MEASURES

Five-year survival.

METHODS

We retrospectively analyzed 733 patients with primary malignant BTVCs in the national cancer database from 2004 through 2015. Univariate and multivariate analyses were used to correlate specific outcome measures with facility volume. Volume was stratified based on cumulative martingale residuals to determine the inflection point of negative to positive impact on survival based on the patient cohort. Long-term survival was compared between patients treated at high and low volume using the Kaplan-Meier method. Only patients with malignant primary tumors were considered eligible for inclusion; patients with incomplete treatment data or benign tumors were excluded.

RESULTS

Patients treated at high-volume centers (HVCs) were younger (p=.0003) and more likely to be insured (p<.0001). There were no significant differences in tumor characteristics. Patients treated at high-volume facilities had improved 5-year survival of 71% versus 58% at low-volume centers (p<.0001). Patients treated at HVCs were more likely to receive surgical treatment (91% vs. 80%, p<.0001); if surgery was performed, they were more likely to undergo an en bloc resection (48% vs. 30%, p<.0001). However, there were no differences in margin status or utilization of radiotherapy or chemotherapy between HVCs and low-volume centers. In a multivariate analysis, facility volume was independently associated with improved survival overall (HR 0.75 [0.58-0.97], p=.03).

CONCLUSIONS

Primary malignant BTVCs are rare, even for HVCs. Despite this, patient survival was significantly improved when treatment was performed at HVCs.

Epidemiologic and survival trends in adult primary bone tumors of the spine

BACKGROUND CONTEXT

Malignant primary spinal tumors are rare making it difficult to perform large studies comparing epidemiologic, survival, and treatment trends. We investigated the largest registry of primary bone tumors, the National Cancer Database (NCDB), to compare epidemiologic and survival trends among these tumors.

PURPOSE

To use the NCDB to describe current epidemiologic trends, treatment modalities, and overall survival rates in patients with chordomas, osteosarcomas, chondrosarcomas, and Ewing sarcomas of the mobile spine. The secondary objective was to determine prognostic factors that impact overall survival rates.

STUDY DESIGN

Retrospective study.

PATIENT SAMPLE

A total of 1,011 patients with primary bone tumors of the spine (377 chordomas, 223 chondrosarcomas, 278 Ewing sarcomas, and 133 osteosarcomas).

OUTCOME MEASURES

Five-year survival.

METHODS

We reviewed the records of 1,011 patients in the NCDB from 2004 through 2015 with histologically confirmed primary osteosarcoma, chondrosarcoma, Ewing sarcoma, or chordoma of the spine. Demographic, clinical, and outcomes data were compiled and compared using chi-squared tests and ANOVA. Long-term survival was compared using the Kaplan-Meier method with statistical comparisons based on the log-rank test. Multivariate analysis was performed to determine survival determinants.

RESULTS

Surgical resection was the primary mode of treatment for chondrosarcoma (90%), chordoma (84%), and osteosarcoma (80%). The treatment for Ewing sarcoma was multimodal involving chemotherapy, radiation therapy, and surgical resection. Five-year survival rates varied significantly with chordomas and chondrosarcomas having the greatest survival (70% and 69%), osteosarcomas having the worse survival (38%), and Ewing having intermediate 5-year survival at 62% (overall log-rank p<.0001). Multivariate analysis demonstrated significantly improved 5-year survival rates with younger age at diagnosis, private insurance status, lower comorbidity score, lower tumor grade, smaller tumor size, surgical resection, and negative surgical margin. Radiation therapy only improved survival for Ewing sarcoma.

CONCLUSIONS

This study provides the most comprehensive description of the epidemiologic, treatment, and survival trends of primary bone tumors of the mobile spine. Second, patient and tumor characteristics associated with improved 5-year survival were identified using a multivariate model.

Prior Hip Arthroscopy Increases Risk for Perioperative Total Hip Arthroplasty Complications: A Matched-Controlled Study

BACKGROUND

Arthroscopic hip surgery is becoming increasingly popular for the treatment of femoroacetabular impingement and labral tears. Reports of outcomes of hip arthroscopy converted to total hip arthroplasty (THA) have been limited by small sample sizes. The purpose of this study was to investigate the impact of prior hip arthroscopy on THA complications.

METHODS

We queried our institutional database from January 2005 and December 2017 and identified 95 hip arthroscopy conversion THAs. A control cohort of 95 primary THA patients was matched by age, gender, and American Society of Anesthesiologists score. Patients were excluded if they had undergone open surgery on the ipsilateral hip. Intraoperative complications, estimated blood loss, operative time, postoperative complications, and need for revision were analyzed. Two separate analyses were performed. The first being intraoperative and immediate postoperative complications through 90-day follow-up and a second separate subanalysis of long-term outcomes on patients with minimum 2-year follow-up.

RESULTS

Average time from hip arthroscopy to THA was 29 months (range 2-153). Compared with primary THA controls, conversion patients had longer OR times (122 vs 103 minutes, P = .003). Conversion patients had a higher risk of any intraoperative complication (P = .043) and any postoperative complication (P = .007), with a higher rate of wound complications seen in conversion patients. There was not an increased risk of transfusion (P = .360), infection (P = 1.000), or periprosthetic fracture between groups (P = .150). When comparing THA approaches independent of primary or conversion surgery, there was no difference in intraoperative or postoperative complications (P = .500 and P = .790, respectively).

CONCLUSION

Conversion of prior hip arthroscopy to THA, compared with primary THA, resulted in increased surgical times and increased intraoperative and postoperative complications. Patients should be counseled about the potential increased risks associated with conversion THA after prior hip arthroscopy.

Traditional Laboratory Markers Hold Low Diagnostic Utility for Immunosuppressed Patients With Periprosthetic Joint Infections

BACKGROUND

Although predictive laboratory markers and cutoffs for immunocompetent patients are well-studied, similar reference ranges and decision thresholds for immunosuppressed patients are less understood. We investigated the utility of typical laboratory markers in immunosuppressed patients undergoing aspiration of a prosthetic hip or knee joint.

METHODS

A retrospective review of adult patients with an immunosuppressed state that underwent primary and revision total joint arthroplasty with a subsequent infection at our tertiary, academic institution was conducted. Infection was defined by Musculoskeletal Infection Society criteria. A multivariable analysis was used to identify independent factors associated with acute (<90 days) and chronic (>90 days) infection. Area under the receiver-operator curve (AUC) was used to determine the best supported laboratory cut points for identifying infection.

RESULTS

We identified 90 patients with immunosuppression states totaling 172 aspirations. Mean follow-up from aspiration was 33 months. In a multivariate analysis, only synovial fluid cell count and synovial percent neutrophils were found to be independently correlated with both acute and chronic infection. A synovial fluid cell count cutoff value of 5679 nucleated cells/mm³ maximized the AUC (0.839) for predicting acute infection, while a synovial fluid cell count cutoff value of 1293 nucleated cells/mm³ maximized the AUC (0.931) for predicting chronic infection.

CONCLUSION

Physicians should be aware of lower levels of synovial nucleated cell count and percentage of neutrophils in prosthetic joint infections of the hip or knee in patients with immunosuppression. Further investigation is necessary to identify the best means of diagnosing periprosthetic joint infection in this patient population.

Algorithm for Management of Periprosthetic Ankle Fractures

BACKGROUND

Evidence on the management of and outcomes from periprosthetic fractures about a total ankle replacement (TAR) are limited. The purpose of this study was to develop an algorithm for the management of patients with postoperative periprosthetic fractures about a TAR.

METHODS

This was a retrospective analysis of patients undergoing a TAR from 2007 through 2017 with a subsequent periprosthetic fracture >4 weeks from index surgery. Implant stability was defined radiographically and intraoperatively where appropriate. Univariate and multivariate analyses were used to identify differences in outcomes. Thirty-two patients were identified with a remote TAR periprosthetic fracture with an average follow-up of 26 months (range, 3-104 months).

RESULTS

Most fractures were located about the medial malleolus (62.5%); the majority of fractures (75%) were deemed to have stable implants. Fractures of the talus always had unstable implants and always required revision TAR surgery (100%, P = .0002). There was no difference in patient-reported outcomes between stable and unstable fractures at an average of 36 months. In a multivariate analysis, fracture location (talus), less time to fracture, and implant type were found to be predictive of unstable implants ( P < .001). Implant stability was independently associated with the need for revision surgery ( P < .049). Nonoperative treatment was independently associated with treatment failure ( P < .001).

CONCLUSION

The majority of stable fractures about a TAR required operative fixation. Management with immobilization was fraught with a high rate of subsequent surgical intervention. We found that fractures about the talus required revision TAR surgery or arthrodesis.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

E-Cadherin Represses Anchorage-Independent Growth in Sarcomas through Both Signaling and Mechanical Mechanisms

CDH1 (also known as E-cadherin), an epithelial-specific cell-cell adhesion molecule, plays multiple roles in maintaining adherens junctions, regulating migration and invasion, and mediating intracellular signaling. Downregulation of E-cadherin is a hallmark of epithelial-to-mesenchymal transition (EMT) and correlates with poor prognosis in multiple carcinomas. Conversely, upregulation of E-cadherin is prognostic for improved survival in sarcomas. Yet, despite the prognostic benefit of E-cadherin expression in sarcoma, the mechanistic significance of E-cadherin in sarcomas remains poorly understood. Here, by combining mathematical models with wet-bench experiments, we identify the core regulatory networks mediated by E-cadherin in sarcomas, and decipher their functional consequences. Unlike carcinomas, E-cadherin overexpression in sarcomas does not induce a mesenchymal-to-epithelial transition (MET). However, E-cadherin acts to reduce both anchorage-independent growth and spheroid formation of sarcoma cells. Ectopic E-cadherin expression acts to downregulate phosphorylated CREB1 (p-CREB) and the transcription factor, TBX2, to inhibit anchorage-independent growth. RNAi-mediated knockdown of TBX2 phenocopies the effect of E-cadherin on CREB levels and restores sensitivity to anchorage-independent growth in sarcoma cells. Beyond its signaling role, E-cadherin expression in sarcoma cells can also strengthen cell-cell adhesion and restricts spheroid growth through mechanical action. Together, our results demonstrate that E-cadherin inhibits sarcoma aggressiveness by preventing anchorage-independent growth. IMPLICATIONS: We highlight how E-cadherin can restrict aggressive behavior in sarcomas through both biochemical signaling and biomechanical effects.

Advanced Patellar Tendinopathy Is Associated With Increased Rates of Bone-Patellar Tendon-Bone Autograft Failure at Early Follow-up After Anterior Cruciate Ligament Reconstruction

Background

Revision anterior cruciate ligament (ACL) reconstruction can be potentially devastating for a patient. As such, it is important to identify prognostic factors that place patients at an increased risk for graft failure. There are no data on the effects of patellar tendinopathy on failure of ACL reconstruction when using a bone-patellar tendon-bone (BPTB) autograft.

Purpose/Hypothesis

The purpose of this study was to investigate the association of patellar tendinopathy with the risk of graft failure in primary ACL reconstruction when using a BPTB autograft. The hypothesis was that patellar tendinopathy would result in higher rates of graft failure when using a BPTB autograft for primary ACL reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

All patients undergoing ACL reconstruction at a single institution from 2005 to 2015 were examined. A total of 168 patients undergoing primary ACL reconstruction with a BPTB autograft were identified. Patients' magnetic resonance imaging scans were reviewed for the presence and grade of patellar tendinopathy by 2 musculoskeletal fellowship-trained radiologists; both were blinded to the aim of the study, patient demographics, surgical details, and outcomes. Patients were divided into 2 groups: failure (defined as presence of symptomatic laxity or graft insufficiency) and success of the ACL graft. Statistical analyses were run to examine the association of patellar tendinopathy with failure of ACL reconstruction using a BPTB autograft.

Results

At a mean follow-up of 18 months, there were 7 (4.2%) patients with graft failure. Moderate or severe patellar tendinopathy was associated with ACL graft failure (P = .011). Age, sex, and side of reconstruction were not associated with the risk of graft failure, although the majority of patients who failed were younger than 20 years. The use of patellar tendons with moderate to severe tendinopathy was associated with a relative risk of ruptures of 6.1 (95% CI, 1.37-27.34) as compared with autograft tendons without tendinopathy.

Conclusion

Moderate or severe patellar tendinopathy significantly increases the risk of graft failure when using a BPTB autograft for primary ACL reconstruction. Patellar tendinopathy should be considered when determining the optimal graft choice for patients undergoing primary ACL reconstruction with autograft tendons.

Tibial Tubercle Osteotomies: a Review of a Treatment for Recurrent Patellar Instability

PURPOSE OF REVIEW

The goal of this review is to provide an overview of current surgical treatment options for tibial tubercle osteotomies as a treatment for recurrent patellofemoral instability. As such we sought to provide the reader with the most current answers to why treatment practices have changed and how this has affected the outcome of surgical treatment for patellar instability.

RECENT FINDINGS

As our understanding of patellofemoral biomechanics have grown, appropriate surgical and non-surgical treatment options have followed suit to address these findings. A clear understanding of the pathomechanics causing the patient's patellar instability is germane to choosing the most appropriate surgical intervention to address this instability. Likewise, understanding the goal of the intervention chosen-e.g., unloading, realignment-is paramount. These surgical techniques may be technically challenging and surgical specialists with experience in these techniques are recommended for optimal outcomes.

Race is an independent predictor of survival in patients with soft tissue sarcoma of the extremities

BACKGROUND

In the United States, race and socioeconomic status are well known predictors of adverse outcomes in several different cancers. Existing evidence suggests that race and socioeconomic status may impact survival in soft tissue sarcoma (STS). We investigated the National Cancer Database (NCDB), which contains several socioeconomic and medical variables and contains the largest sarcoma patient registry to date. Our goal was to determine the impact of race, ethnicity and socioeconomic status on patient survival in patients with soft tissue sarcoma of the extremities (STS-E).

METHODS

We retrospectively analyzed 14,067 STS-E patients in the NCDB from 1998 through 2012. Patients were stratified based on race, ethnicity and socioeconomic status. Univariate and multivariate analyses were used to correlate specific outcomes and survival measures with these factors. Then, long-term survival between groups was evaluated using the Kaplan-Meier (KM) method with comparisons based on the log-rank test. Multiple variables were analyzed between two groups.

RESULTS

Of the 14,067 patients analyzed, 84.9% were white, 11% were black and 4.1% were Asian. Black patients were significantly more likely (7.18% vs 5.65% vs 4.47%) than white or Asian patients to receive amputation (p = 0.027). Black patients were also less likely to have either an above-median education level or an above-median income level (p < 0.001). In addition, black patients were more likely to be uninsured (p < 0.001) and more likely to have a higher Charleson Comorbidity Score than white or Asian patients. Tumors were larger in size upon presentation in black patients than in white or Asian patients (p < 0.001). Black patients had significantly poorer overall survival than did white or Asian patients (p < 0.001) with a KM 5-year survival of 61.4% vs 66.9% and 69.9% respectively, and a 24% higher independent likelihood of dying in a multivariate analysis.

CONCLUSION

This large database review reveals concerning trends in black patients with STS-E. These include larger tumors, poorer resources, a greater likelihood of amputation, and poorer survival than white and Asian patients. Future studies are warranted to help ensure adequate access to effective treatment for all patients.

Novel Use of Active Leptospermum Honey for Ringed Fixator Pin Site Care in Diabetic Charcot Deformity Patients

INTRODUCTION

Open reduction with external fixation (OREF) utilizing fine wire ringed fixators for correction of Charcot deformity has gained popularity over the past decade. Pin site infections are a well-documented complication of external fixation as well as a driver of escalating health care costs. We aimed to demonstrate the safety and efficacy of a novel method of pin site care utilizing active Leptospermum honey-impregnated dressings (MediHoney) in diabetic patients undergoing deformity correction with OREF.

METHODS

Twenty-one diabetic patients with Charcot deformities of the lower extremity were prospectively enrolled and followed for pin site complications following OREF for deformity correction. Active Leptospermum honey dressings were applied at metal-cutaneous interfaces at the end of the OREF procedure and replaced weekly for a total of 8 weeks. Patients were monitored for pin site infections from the time of surgery until external fixator removal. Sixteen consecutive patients receiving standard OREF for Charcot deformities were evaluated retrospectively to serve as a control group.

RESULTS

Of the 21 enrolled patients, 19 underwent OREF and followed up throughout the study period. Treated patients had a mean age of 58.5 years and mean body mass index measuring 33.3 kg/m² as documented prior to surgery. The 15 patients with hemoglobin A1c labs drawn in the 3 months preceding surgery averaged 7.5. Fixators were removed at an average of 12.1 weeks after adequate bony healing. Of the 244 pin sites in 19 patients, 3 pin sites (1.2% of pins) in 2 patients (10.5% of patients) showed evidence of superficial infection. All infections resolved with oral antibiotics. Infection rates were significantly reduced when compared to the standard care control group.

CONCLUSIONS

Pilot data in a prospectively collected case series demonstrate safety and efficacy of active Leptospermum honey-impregnated dressings when used for fine wire ringed fixator pin site care in diabetic Charcot deformity patients. Further investigation in the form of a prospective randomized controlled study is warranted to demonstrate the potential value of this novel intervention.

LEVELS OF EVIDENCE

Level IV.

Midterm Outcomes of a Fixed-Bearing Total Ankle Arthroplasty With Deformity Analysis

BACKGROUND

We present our results with an INBONE I (Wright Medical, Memphis, TN) prosthesis that have a minimum of 4 to 10 years of follow-up and include a preoperative deformity analysis on outcomes.

METHODS

A consecutive series of 149 patients, from 2007 to 2011, at a single institution were enrolled. Pain and patient-reported function were assessed preoperatively and at yearly follow-ups. We analyzed the data for complications, reoperations, and failures (defined as undergoing revision for exchange or removal of one or both metallic components for any reason). Patients were also grouped according to coronal plane tibiotalar alignment; either ≥10 degrees or <10 degrees, and these outcomes were compared. Our follow-up ranged from 48 to 113 months (average 5.9 years).

RESULTS

There was significant improvement ( P < .05) in the visual analog scale for pain, American Orthopaedic Foot & Ankle Society hindfoot scale, Short Musculoskeletal Function Assessment, and Short Form 36-Item Health Survey scores at most recent follow-up. There were 14 implant failures with overall survivorship of 90.6% (135/149). Reasons for failure included cysts/loosening (7), talar subsidence (4), fractured component (1), impingement pain (1), and infection (1). Seventy-two patients (48.3%) with preoperative coronal plane deformity of ≥10 degrees varus or valgus were compared to 78 patients (51.7%) with <10 degrees deformity. There was no difference in patient outcome scores or revision rates between these patient groups. There was a statistically significant difference ( P = .039) in reoperation rates among patients with ≥10 degrees deformity (22.2%) compared to those without such a deformity (37.7%) Conclusion: Patients who underwent INBONE I fixed-bearing total ankle arthroplasty demonstrated significant improvement in outcomes at a mean of 5.9 years. Catastrophic talar component collapse did occur (2.7% of cases), but relatively rarely. The patients with preoperative coronal plane tibiotalar deformity had similar pain relief, function, and need for revision of implant components. Despite the presumed shortcomings of the INBONE I's design, this implant showed promising results, with or without deformity, at midterm follow-up with survivorship of 90.6%.

LEVEL OF EVIDENCE

Level III, comparative study.

A Novel Imaging System Distinguishes Neoplastic from Normal Tissue During Resection of Soft Tissue Sarcomas and Mast Cell Tumors in Dogs

OBJECTIVE

To assess the ability of a novel imaging system designed for intraoperative detection of residual cancer in tumor beds to distinguish neoplastic from normal tissue in dogs undergoing resection of soft tissue sarcoma (STS) and mast cell tumor (MCT).

STUDY DESIGN

Non-randomized prospective clinical trial.

ANIMALS

12 dogs with STS and 7 dogs with MCT.

METHODS

A fluorescent imaging agent that is activated by proteases in vivo was administered to the dogs 4-6 or 24-26 hours before tumor resection. During surgery, a handheld imaging device was used to measure fluorescence intensity within the cancerous portion of the resected specimen and determine an intensity threshold for subsequent identification of cancer. Selected areas within the resected specimen and tumor bed were then imaged, and biopsies (n=101) were obtained from areas that did or did not have a fluorescence intensity exceeding the threshold. Results of intraoperative fluorescence and histology were compared.

RESULTS

The imaging system correctly distinguished cancer from normal tissue in 93/101 biopsies (92%). Using histology as the reference, the sensitivity and specificity of the imaging system for identification of cancer in biopsies were 92% and 92%, respectively. There were 10/19 (53%) dogs which exhibited transient facial erythema soon after injection of the imaging agent which responded to but was not consistently prevented by intravenous diphenhydramine.

CONCLUSION

A fluorescence-based imaging system designed for intraoperative use can distinguish canine soft tissue sarcoma (STS) and mast cell tumor (MCT) tissue from normal tissue with a high degree of accuracy. The system has potential to assist surgeons in assessing the adequacy of tumor resections during surgery, potentially reducing the risk of local tumor recurrence. Although responsive to antihistamines, the risk of hypersensitivity needs to be considered in light of the potential benefits of this imaging system in dogs.

A mouse-human phase 1 co-clinical trial of a protease-activated fluorescent probe for imaging cancer

Local recurrence is a common cause of treatment failure for patients with solid tumors. Intraoperative detection of microscopic residual cancer in the tumor bed could be used to decrease the risk of a positive surgical margin, reduce rates of reexcision, and tailor adjuvant therapy. We used a protease-activated fluorescent imaging probe, LUM015, to detect cancer in vivo in a mouse model of soft tissue sarcoma (STS) and ex vivo in a first-in-human phase 1 clinical trial. In mice, intravenous injection of LUM015 labeled tumor cells, and residual fluorescence within the tumor bed predicted local recurrence. In 15 patients with STS or breast cancer, intravenous injection of LUM015 before surgery was well tolerated. Imaging of resected human tissues showed that fluorescence from tumor was significantly higher than fluorescence from normal tissues. LUM015 biodistribution, pharmacokinetic profiles, and metabolism were similar in mouse and human subjects. Tissue concentrations of LUM015 and its metabolites, including fluorescently labeled lysine, demonstrated that LUM015 is selectively distributed to tumors where it is activated by proteases. Experiments in mice with a constitutively active PEGylated fluorescent imaging probe support a model where tumor-selective probe distribution is a determinant of increased fluorescence in cancer. These co-clinical studies suggest that the tumor specificity of protease-activated imaging probes, such as LUM015, is dependent on both biodistribution and enzyme activity. Our first-in-human data support future clinical trials of LUM015 and other protease-sensitive probes.

A Fluorescence-Guided Laser Ablation System for Removal of Residual Cancer in a Mouse Model of Soft Tissue Sarcoma

The treatment of soft tissue sarcoma (STS) generally involves tumor excision with a wide margin. Although advances in fluorescence imaging make real-time detection of cancer possible, removal is limited by the precision of the human eye and hand. Here, we describe a novel pulsed Nd:YAG laser ablation system that, when used in conjunction with a previously described molecular imaging system, can identify and ablate cancer in vivo. Mice with primary STS were injected with the protease-activatable probe LUM015 to label tumors. Resected tissues from the mice were then imaged and treated with the laser using the paired fluorescence-imaging/ laser ablation device, generating ablation clefts with sub-millimeter precision and minimal underlying tissue damage. Laser ablation was guided by fluorescence to target tumor tissues, avoiding normal structures. The selective ablation of tumor implants in vivo improved recurrence-free survival after tumor resection in a cohort of 14 mice compared to 12 mice that received no ablative therapy. This prototype system has the potential to be modified so that it can be used during surgery to improve recurrence-free survival in patients with cancer.

Rotator cuff tears in young patients: a different disease than rotator cuff tears in elderly patients

BACKGROUND

The purpose of this study was to conduct a systematic review of the literature to evaluate the characteristics of injury and treatment outcomes of rotator cuff tears in young patients.

METHODS

A systematic electronic search was performed for clinical studies evaluating rotator cuff tears in patients younger than 40 years with special emphasis on reporting of injury characteristics and treatment outcomes with a minimum 1-year follow-up.

RESULTS

Twelve studies (involving 336 patients) met inclusion criteria. The mean age of the patients was 28 years (range, 16-40 years), with a mean follow-up of 39 months. There were 2 distinct subgroups. The majority of studies (7 of 10) showed that patients typically had a full-thickness tear with an acute traumatic etiology. However, within the subgroup of elite throwers, 5 of 6 studies demonstrated a majority of tears that were partial thickness stemming from chronic overuse. Rotator cuff repair improved pain and strength in almost all studies reporting on these parameters. Eighty-seven percent of patients reported they were satisfied. However, all studies examining elite throwers showed significant difficulty in returning to play (25%-97%).

CONCLUSIONS

In young patients with rotator cuff tears, there are 2 primary groups. (1) A majority group with rotator cuff tears of traumatic origin responded well to both arthroscopic and open rotator cuff repair in terms of pain relief and self-reported outcomes postoperatively. These patients reported high levels of satisfaction and return to preinjury level of play. (2) A unique subpopulation composed of elite throwers had improved outcomes but suboptimal return to play.

The Use of Radiation Therapy in Well-Differentiated Soft Tissue Sarcoma of the Extremities: An NCDB Review

Objective. This study investigated patterns of utilization of radiation therapy (RT) and correlated this with overall survival by assessing patients with well-differentiated soft tissue sarcoma of the extremity (STS-E) in the National Cancer Database (NCDB). Methods. All patients diagnosed with well-differentiated STS-E between 1998 and 2006 were identified in the NCDB. Patients were stratified by use of surgery alone versus use of adjuvant RT after surgery and analyzed using multivariate analysis, Kaplan-Meier analysis, and propensity matching. Results. 2113 patients with well-differentiated STS-E were identified in the NCDB for inclusion with a mean follow-up time of 74 months. 69% of patients were treated with surgery alone, while 26% were treated with surgery followed by adjuvant RT. Patients undergoing amputation were less likely to receive adjuvant RT. There was no difference in overall survival between patients with well-differentiated STS treated with surgery alone and those patients who received adjuvant RT. Conclusions. In the United States, adjuvant RT is being utilized in a quarter of patients being treated for well-differentiated STS-E. While the use of adjuvant RT may be viewed as a means to facilitate limb salvage, this large national database review confirms no survival benefit, regardless of tumor size or margin status.