Custom three-dimensional printed implants for reconstruction of oncologic pelvic defects.

The use of three-dimensional printed implants in the field of orthopedic surgery has become increasingly popular and has potentiated hip reconstruction in the setting of oncologic resections of the pelvis and acetabulum. In this review, we examine and discuss the indications and technical considerations for custom implant reconstruction of pelvic defects.

Mechanically Triggered Carbon Monoxide Release with Turn-On Aggregation-Induced Emission.

Polymers that release functional small molecules under mechanical stress potentially serve as next-generation materials for catalysis, sensing, and mechanochemical dynamic therapy. To further expand the function of mechanoresponsive materials, the discovery of chemistries capable of small molecule release are highly desirable. In this report, we detail a nonscissile bifunctional mechanophore (i.e., dual mechano-activated properties) based on a unique mechanochemical reaction involving norborn-2-en-7-one (NEO). One property is the release of carbon monoxide (CO) upon pulsed solution ultrasonication. A release efficiency of 58% is observed at high molecular weights (Mn = 158.8 kDa), equating to ∼154 molecules of CO released per chain. The second property is the bright cyan emission from the macromolecular product in its aggregated state, resulting in a turn-on fluorescence readout coincident with CO release. This report not only demonstrates a unique strategy for the release of small molecules in a nonscissile way but also guides future designs of force-responsive aggregation-induced emission (AIE) luminogens.

A prospective real-world study of the diffuse-type tenosynovial giant cell tumor patient journey: A 2-year observational analysis.

BACKGROUND AND OBJECTIVES: Diffuse-tenosynovial giant cell tumor (D-TGCT) is a rare, locally aggressive, typically benign neoplasm affecting mainly large joints, representing a wide clinical spectrum. We provide a picture of the treatment journey of D-TGCT patients as a 2-year observational follow-up. METHODS: The TGCT Observational Platform Project registry was a multinational, multicenter, prospective observational study at tertiary sarcoma centers spanning seven European countries and two US sites. Histologically confirmed D-TGCT patients were categorized as either those who remained on initial treatment strategy (determined at baseline visit) or those who changed treatment strategy with specific changes documented (e.g., systemic treatment to surgery) at the 1-year and/or 2-year follow-up visits. RESULTS: A total of 176 patients were assessed, mean diagnosis age was 38.4 (SD ± 14.6) years; most patients had a knee tumor (120/176, 68.2%). For the 2-year observation period, most patients (75.5%) remained on the baseline treatment strategy throughout, 54/79 patients (68.4%) remained no treatment, 30/45 patients (66.7%) remained systemic treatment, 39/39 patients (100%) remained surgery. Those who changed treatment strategy utilized multimodal treatment options. CONCLUSIONS: This is the first prospectively collected analysis to describe D-TGCT patient treatments over an extended follow-up and demonstrates the need for multidisciplinary teams to determine an optimal treatment strategy.

Long term outcomes of total humeral replacement for oncological reconstructions: A single institution experience.

BACKGROUND: There is a paucity of data on long-term survivorship and outcomes for total humerus replacements (THR) with only two series reporting 10-year survival. PATIENTS AND METHODS: A review of 769 consecutive, prospectively collected endoprosthetic reconstructions for oncological diagnoses at a single-center between 1980 and 2019 was performed. Patients with THRs were isolated and analyzed for outcomes, complications, and modes of failure. RESULTS: Eighteen patients with 20 THR implants were identified. The median follow-up for surviving patients was 148 months (interquartile range [IQR] = 74-194) and 60 months (IQR = 17-155 months) for all patients. Two prostheses required revision for failure, both for symptomatic shoulder dislocation. There were three local recurrences. Revision-free survival at 5, 10, and 15 years was 100%, 86% and 86%, respectively. There were no cases of ulnar component failure, radial nerve palsy, or periprosthetic infection. CONCLUSIONS: THR prosthesis survivorship is comparable to the previous series, with a longer follow-up than has previously been reported. Symptomatic shoulder instability was common (25%), and was the only cause of revision. Reverse total shoulder could be an important way to address this in the future. Local recurrence rates were high, as has been reported elsewhere for THR.

Management of Pigmented Villonodular Synovitis (PVNS): an Orthopedic Surgeon's Perspective.

PURPOSE OF REVIEW: Pigmented villonodular synovitis (PVNS) or tenosynovial giant cell tumor (TGCT) encompasses a wide spectrum of disease and is divided into localized and diffuse variants. Surgical resection remains the principal treatment for nearly all localized type disease and most diffuse type. Recent mechanistic understanding of the disease led to drug discovery that has opened new avenues for patients with recalcitrant disease. In this manuscript, we review the current treatment options for TGCT, presenting outcomes from traditional surgical approaches as well as those from nonsurgical approaches. RECENT FINDINGS: Arthroscopic and/or open surgery remains the mainstay of treatment for TGCT for the vast majority of patients. While radiosynoviorthesis and external beam radiation have been used for recalcitrant disease, recent understanding of the colony stimulating factor 1 receptor (CSF1R) pathway and its paracrine and autocrine role in TGCT has led to the development of targeted inhibitors. Their optimal role and efficacy are unclear due to limited number of high-quality studies and contradictory results; however, recent and ongoing studies suggest there may be a role for their use, especially in diffuse and/or refractory disease. Surgery remains the most common treatment for TGCT, however, there may be an increasing role for adjuvant therapies, including the new targeted agents. Weighing the side effects of these treatments against the symptomatic benefit on a patient-by-patient basis in this benign disease remains critical.

Is Core Needle Biopsy Reliable in Differentiating Between Aggressive Benign and Malignant Radiolucent Bone Tumors?

BACKGROUND: Although there is widespread acceptance of core needle biopsy (CNB) for diagnosing solid tumors, there is reluctance by some clinicians to use CNB for aneurysmal bone cysts (ABCs) as a result of concerns of safety (bleeding, nerve injury, fracture, readmission, or infection) and reliability, particularly to rule out malignant diagnoses like telangiectatic osteosarcoma. This is especially true when CNB tissue is sent from an outside hospital, where the technique used to obtain the tissue may be spurious. QUESTIONS/PURPOSES: (1) Is CNB effective (provided adequate information to indicate appropriate surgical treatment without further open biopsy) as an initial diagnostic test for ABC? (2) Is CNB accurate (pathology consistent with the subsequent definitive surgical pathologic diagnosis) in differentiating between benign lesions such as primary or secondary ABCs and malignant radiolucent lesions such as telangiectatic osteosarcoma? (3) What are the complications of CNB? (4) Is there any difference in the effectiveness or accuracy of CNB performed at outside institutions when compared with a referral center? METHODS: A retrospective study of our musculoskeletal tumor board pathology database (1990-2016) was performed using search criteria "aneurysmal bone cyst" or "telangiectatic osteosarcoma." Only patients undergoing a CNB who proceeded to definitive surgical resection with final pathology were included. Excluding outside CNBs, CNB was performed after presentation at a musculoskeletal tumor board as a result of atypical features on imaging or history concerning for malignancy. Outside CNB tissue was reviewed by our pathologists. If there was sufficient tissue for diagnosis, the patient proceeded to definitive surgery. If not, the patient underwent open biopsy. CNB diagnosis, open biopsy results, and open surgical resection pathology were reviewed. Complications, including bleeding, infection, nerve injury, readmission, or fracture, between the CNB and definitive open surgical procedure (mean 1.6 months) were documented. CNBs were considered "effective" if they yielded pathology considered sufficient to proceed with appropriate definitive surgery without additional open biopsy. CNBs were considered "accurate" if they were effective and yielded a pathologic diagnosis that matched the subsequent definitive surgical pathology. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of obtaining a malignant diagnosis using CNB were also calculated. RESULTS: A total of 81% (59 of 73) of CNBs were effective. Ninety-three percent (55 of 59) of CNBs were classified as accurate. Diagnostic CNBs had a sensitivity and specificity of 89% (eight of nine) and 100% (51 of 51), respectively. The PPV was 1.00 and the NPV was 0.82. There were no complications. With the numbers available, there was no difference in efficacy (90% [37 of 41 versus 14 of 15]; odds ratio, 0.97 [95% confidence interval {CI}, 0.41-2.27], p = 0.94) or accuracy (92% [34 of 37 versus 13 of 14]; odds ratio, 0.87 [95% CI, 0.08-9.16], p = 0.91) between CNBs performed in house and those referred from outside. CONCLUSIONS: These data suggest that CNBs are useful as an initial diagnostic test for ABC and telangiectatic osteosarcoma. Tissue from outside CNBs can be read reliably without repeat biopsy. If confirmed by other institutions, CNB may be considered a reasonable approach to the diagnosis of aggressive, radiolucent lesions of bone. LEVEL OF EVIDENCE: Level III, diagnostic study.

Reconstructive Science in Orthopedic Oncology.

Limb salvage is widely practiced as standard of care in most cases of extremity bone sarcoma. Allograft and endoprosthesis reconstructions are the most widely utilized modalities for the reconstruction of large segment defects, however complication rates remain high. Aseptic loosening and infection remain the most common modes of failure. Implant integration, soft-tissue function, and infection prevention are crucial for implant longevity and function. Macro and micro alterations in implant design are reviewed in this manuscript. Tissue engineering principles using nanoparticles, cell-based, and biological augments have been utilized to develop implant coatings that improve osseointegration and decrease infection. Similar techniques have been used to improve the interaction between soft tissues and implants. Tissue engineered constructs (TEC) used in combination with, or in place of, traditional reconstructive techniques may represent the next major advancement in orthopaedic oncology reconstructive science, although preclinical results have yet to achieve durable translation to the bedside.

Evaluation of preoperative and intraoperative red blood cell transfusion practices at Maputo Central Hospital, Mozambique.

BACKGROUND: The purpose of this study was to evaluate preoperative and intraoperative blood transfusion practices in Hospital Central (Maputo, Mozambique) and estimate the number of potentially avoidable transfusions. STUDY DESIGN AND METHODS: A retrospective cohort study was performed. Age, comorbidities, hemoglobin (Hb), the potential for blood loss, and units of red blood cell (RBC) transfusions were recorded. Preoperative transfusions were evaluated to determine whether they met criteria established by the Mozambican Ministry of Health as well as proposed guidelines based on more restrictive protocols. Avoidable blood transfusions were defined as those preoperative transfusions that were not indicated based on these guidelines. Multivariate logistic regression was used to identify factors that predicted transfusion. RESULTS: A total of 205 patients (age range, 0.1-86 years) underwent surgery in the main operating room during the 2-week study period. Overall, 35 (17%) patients received 68 transfusions. Of these, 36 transfusions were given preoperatively and 32 were given intraoperatively. Thirty-six percent of preoperative transfusions were avoidable according to national guidelines. Ninety-two percent were avoidable using more restrictive guidelines. The primary predictors of preoperative blood transfusion were lower Hb (odds ratio [OR], 0.390/1 g/dL; p < 0.0001) and the potential for blood loss (OR, 3.73; p = 0.0410). CONCLUSIONS: Adherence to existing Hb thresholds recommended by national blood transfusion guidelines could significantly reduce the number of transfusions and the association risk of transfusion-transmissible infections. Adoption of more restrictive guidelines is recommended to further improve blood transfusion utilization and further reduce the transmission risk of human immunodeficiency virus and hepatitis.

Solitary diverticular type V bile duct cyst.

Bile duct cysts are a rare form of biliary disease characterized by single or multiple dilations anywhere along the biliary tree. Todani Type V bile duct cysts are intrahepatic and typically involve multiple fusiform dilations. We present the case of a neonate with an unusual prenatally identified solitary diverticular type V bile duct cyst that was evaluated, monitored, and subsequently resected with right lobectomy at the age of 6 months. The importance of imaging in diagnosis and approaches to management are discussed.

The evolution of diverse antimicrobial responses in vancomycin-intermediate Staphylococcus aureus and its therapeutic implications.

Staphylococcus aureus causes endocarditis, osteomyelitis, and bacteremia. Clinicians often prescribe vancomycin as an empiric therapy to account for methicillin-resistant S. aureus (MRSA) and narrow treatment based on culture susceptibility results. However, these results reflect a single time point before empiric treatment and represent a limited subset of the total bacterial population within the patient. Thus, while they may indicate that the infection is susceptible to a particular drug, this recommendation may no longer be accurate during therapy. Here, we addressed how antibiotic susceptibility changes over time by accounting for evolution. We evolved 18 methicillin-susceptible S. aureus (MSSA) populations under increasing vancomycin concentrations until they reached intermediate resistance levels. Sequencing revealed parallel mutations that affect cell membrane stress response and cell-wall biosynthesis. The populations exhibited repeated cross-resistance to daptomycin and varied responses to meropenem, gentamicin, and nafcillin. We accounted for this variability by deriving likelihood estimates that express a population's probability of exhibiting a drug response following vancomycin treatment. Our results suggest antistaphylococcal penicillins are preferable first-line treatments for MSSA infections but also highlight the inherent uncertainty that evolution poses to effective therapies. Infections may take varied evolutionary paths; therefore, considering evolution as a probabilistic process should inform our therapeutic choices.

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.

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.

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.

Monoclonal Antibody Disrupts Biofilm Structure and Restores Antibiotic Susceptibility in an Orthopedic Implant Infection Model.

Bacterial biofilms on orthopedic implants are resistant to the host immune response and to traditional systemic antibiotics. Novel therapies are needed to improve patient outcomes. TRL1068 is a human monoclonal antibody (mAb) against a biofilm anchoring protein. For assessment of this agent in an orthopedic implant infection model, efficacy was measured by reduction in bacterial burden of Staphylococcus aureus, the most common pathogen for prosthetic joint infections (PJI). Systemic treatment with the biofilm disrupting mAb TRL1068 in conjunction with vancomycin eradicated S. aureus from steel pins implanted in the spine for 26 of 27 mice, significantly more than for vancomycin alone. The mechanism of action was elucidated by two microscopy studies. First, TRL1068 was localized to biofilm using a fluorescent antibody tag. Second, a qualitative effect on biofilm structure was observed using scanning electron microscopy (SEM) to examine steel pins that had been treated in vivo. SEM images of implants retrieved from control mice showed abundant three-dimensional biofilms, whereas those from mice treated with TRL1068 did not. Clinical Significance: TRL1068 binds at high affinity to S. aureus biofilms, thereby disrupting the three-dimensional structure and significantly reducing implant CFUs in a well-characterized orthopedic model for which prior tested agents have shown only partial efficacy. TRL1068 represents a promising systemic treatment for orthopedic implant infection.

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.

The Utility of Chest Imaging for Surveillance of Atypical Lipomatous Tumors.

BACKGROUND: Unlike other soft tissue sarcomas, atypical lipomatous tumors (ALTs) are thought to have a low propensity for metastasis. Despite this, a standard of care for pulmonary metastasis (PM) surveillance has not been established. This study aimed to evaluate the utility of chest imaging for PM surveillance following ALT excision. METHODS: This was a multi-institution, retrospective review of all patients with primary ALTs of the extremities or superficial torso who underwent excision between 2006 and 2018. Minimum follow-up was two years. Long-term survival was evaluated using the Kaplan-Meier method. RESULTS: 190 patients with ALT were included. Average age was 61.7 years and average follow-up was 58.6 months (24 to 180 months). MDM2 testing was positive in 88 patients (46.3%), and 102 (53.7%) did not receive MDM2 testing. 188 patients (98.9%) had marginal excision, and 127 (66.8%) had marginal or positive margins. Patients received an average of 0.9 CT scans and 1.3 chest radiographs over the surveillance period. 10-year metastasis-free survival was 100%, with no documented deaths from disease. CONCLUSIONS: This study suggests that chest imaging does not have a significant role in PM surveillance following ALT excision, but advanced local imaging and chest surveillance may be considered in cases of local recurrence or concern for dedifferentiation.

Point-of-care antimicrobial coating protects orthopaedic implants from bacterial challenge.

Implant related infections are the most common cause of joint arthroplasty failure, requiring revision surgeries and a new implant, resulting in a cost of $8.6 billion annually. To address this problem, we created a class of coating technology that is applied in the operating room, in a procedure that takes less than 10 min, and can incorporate any desired antibiotic. Our coating technology uses an in situ coupling reaction of branched poly(ethylene glycol) and poly(allyl mercaptan) (PEG-PAM) polymers to generate an amphiphilic polymeric coating. We show in vivo efficacy in preventing implant infection in both post-arthroplasty infection and post-spinal surgery infection mouse models. Our technology displays efficacy with or without systemic antibiotics, the standard of care. Our coating technology is applied in a clinically relevant time frame, does not require modification of implant manufacturing process, and does not change the implant shelf life.

Comparison of two fluorescent probes in preclinical non-invasive imaging and image-guided debridement surgery of Staphylococcal biofilm implant infections.

Implant-associated infections are challenging to diagnose and treat. Fluorescent probes have been heralded as a technologic advancement that can improve our ability to non-invasively identify infecting organisms, as well as guide the inexact procedure of surgical debridement. This study's purpose was to compare two fluorescent probes for their ability to localize Staphylococcus aureus biofilm infections on spinal implants utilizing noninvasive optical imaging, then assessing the broader applicability of the more successful probe in other infection animal models. This was followed by real-time, fluorescence image-guided surgery to facilitate debridement of infected tissue. The two probe candidates, a labelled antibiotic that targets peptidoglycan (Vanco-800CW), and the other, a labelled antibody targeting the immunodominant Staphylococcal antigen A (1D9-680), were injected into mice with spine implant infections. Mice were then imaged noninvasively with near infrared fluorescent imaging at wavelengths corresponding to the two probe candidates. Both probes localized to the infection, with the 1D9-680 probe showing greater fidelity over time. The 1D9-680 probe was then tested in mouse models of shoulder implant and allograft infection, demonstrating its broader applicability. Finally, an image-guided surgery system which superimposes fluorescent signals over analog, real-time, tissue images was employed to facilitate debridement of fluorescent-labelled bacteria.

Long-term follow-up of all-polyethylene tibial components when used for oncological endoprosthetic reconstruction.

AIMS: We aimed to examine the long-term mechanical survivorship, describe the modes of all-cause failure, and identify risk factors for mechanical failure of all-polyethylene tibial components in endoprosthetic reconstruction. METHODS: This is a retrospective database review of consecutive endoprosthetic reconstructions performed for oncological indications between 1980 and 2019. Patients with all-polyethylene tibial components were isolated and analyzed for revision for mechanical failure. Outcomes included survival of the all-polyethylene tibial component, revision surgery categorized according to the Henderson Failure Mode Classification, and complications and functional outcome, as assessed by the Musculoskeletal Tumor Society (MSTS) score at the final follow-up. RESULTS: A total of 278 patients were identified with 289 all-polyethylene tibial components. Mechanical survival was 98.4%, 91.1%, and 85.2% at five, ten and 15 years, respectively. A total of 15 mechanical failures were identified at the final follow-up. Of the 13 all-polyethylene tibial components used for revision of a previous tibial component, five (38.5%) failed mechanically. Younger patients (< 18 years vs > 18 years; p = 0.005) and those used as revision components (p < 0.001) had significantly increased rates of failure. Multivariate logistic regression modelling showed revision status to be a positive risk factor for failure (odds ratio (OR) 19.498, 95% confidence interval (CI) 4.598 to 82.676) and increasing age was a negative risk factor for failure (OR 0.927, 95% CI 0.872 to 0.987). Age-stratified risk analysis showed that age > 24 years was no longer a statistically significant risk factor for failure. The final mean MSTS score for all patients was 89% (8.5% to 100.0%). CONCLUSION: The long-term mechanical survivorship of all-polyethylene tibial components when used for tumour endoprostheses was excellent. Tumour surgeons should consider using these components for their durability and the secondary benefits of reduced cost and ease of removal and revision. However, caution should be taken when using all-polyethylene tibial components in the revision setting as a significantly higher rate of mechanical failure was seen in this group of patients. Cite this article: Bone Joint J. 2020;102-B(2):170-176.