Reactivity of a triamidoamine terminal uranium(VI)-nitride with 3d-transition metal metallocenes.

Reactions between [(TrenTIPS)UVIN] (1, TrenTIPS = {N(CH2CH2NSiPri3)3}3-) and [MII(η5-C5R5)2] (M/R = Cr/H, Mn/H, Fe/H, Ni/H) were intractable, but M/R = Co/H or Co/Me afforded [(TrenTIPS)UVN-(η1:η4-C5H5)CoI(η5-C5H5)] (2) and [(TrenTIPS)UIV-NH2] (3), respectively. For M/R = V/H [(TrenTIPS)UIV-NVIV(η5-C5H5)2] (4), was isolated. Complexes 2-4 evidence one-/two-electron uranium reductions, nucleophilic nitrides, and partial N-atom transfer.

Outcomes and complications of postoperative seroma cavities following soft-tissue sarcoma resection.

Introduction: Seroma development is a known complication following extremity and trunk soft-tissue sarcoma (STS) resection. The purpose of this study is to evaluate and characterize seroma outcomes and the development of associated complications. Methods: A retrospective review of 123 patients who developed postoperative seromas following STS resection at a single institution was performed. Various patient and surgical factors were analyzed to determine their effect on overall seroma outcomes. Results: 77/123 seromas (62.6%) were uncomplicated, 30/123 (24.4%) developed infection, and 16/123 (13.0%) were symptomatic and required aspiration or drainage for symptom relief at an average of 12.2 months postoperatively. 65/123 (52.8%) seromas resolved spontaneously at an average time of 12.41 months. Seromas in the lower extremity (p=0.028), surgical resection volume >864 cm3, (p=<0.001) and initial seroma volume >42 cm3 (p=<0.001) increased the likelihood of infection. 90% of infected seromas developed the infection within the first three months following initial resection. No seromas which were aspirated or drained ultimately developed an infection following these procedures, though 50% recurred. Discussion: Most seromas following STS resection are uncomplicated and do not require intervention, though a large resection cavity >864 cm3 and a large seroma volume >42 cm3 are risk factors for complications.

Outcomes of limited stage primary bone diffuse large B-cell lymphoma in the rituximab era: a multicenter, retrospective study.

Primary bone diffuse large B cell lymphoma (DLBCL) is a rare variant of extranodal non-Hodgkin lymphoma (NHL) historically treated with induction chemotherapy followed by consolidative radiation therapy (RT). It remains unknown whether RT confers additional benefit following rituximab-based chemoimmunotherapy (CIT) induction in patients with limited-stage disease. We conducted a multicenter retrospective analysis of patients treated between 2005 and 2019 using rituximab-based CIT regimens with or without consolidative RT to discern whether consolidative RT adds benefit in patients with stage I-II disease that could be encompassed in one radiation field. A total of 112 patients were included: 78 received CIT and radiation (RT group), and 34 received CIT alone (no RT group). The OS at 10 years was 77.9% in the RT group and 89.0% in the no RT group (p = 0.42). The RFS at 10 years was 73.5% in the RT group and 80.3% in the no RT group (p = 0.88). Neither improved OS nor RFS was associated with the addition of consolidative RT. Subgroup analysis of patients only achieving a partial response after CIT suggests that these patients may benefit from consolidative RT.

Natural history of intraosseous low-grade chondroid lesions of the proximal humerus.

Introduction: Enchondromas and grade 1 chondrosarcomas are commonly encountered low-grade chondroid tumors in the proximal humerus. While there is a concern for malignant transformation, few studies have evaluated the natural history of these lesions. The purpose of this study is to evaluate the natural history of proximal humerus low-grade chondroid lesions managed both conservatively and surgically, and to define management criteria using clinical and radiographic findings for these low-grade chondroid lesions. Methods: The patient population included 90 patients intended for conservative treatment and 22 patients proceeding directly to surgery. Data collection was based on a combination of chart review and patient imaging and descriptive statistics were calculated for each group. Results: No malignant transformations were noted amongst any group. In the conservative treatment group, 7 of 64 (11%) progressed to surgery after an average of 20.3 months of conservative treatment due to persistent pain unexplained by other shoulder pathology. Importantly, 71% experienced continued pain at a mean of 53.1 months post-operatively. The group that went directly to surgery also demonstrated pain in 41% at an average follow-up of 57.3 months. Discussion: Low-grade cartilaginous lesions of the proximal humerus without concerning imaging findings can be managed with conservative treatment and the risk of malignant transformation is very low. Patients with a clear source of their shoulder pain unrelated to their tumor and without concerning characteristics on imaging can be managed with serial annual radiographic imaging. Patients undergoing surgery for these indolent tumors are likely to experience persistent pain even after surgery.

Stereotactic body radiotherapy for metastatic sarcoma to the lung: adding to the arsenal of local therapy.

INTRODUCTION: Conventional treatment of pulmonary metastatic sarcoma primarily involves surgery, with systemic therapy added in select patients. However, broader applications of radiation therapy techniques have prompted investigation into the use of stereotactic body radiotherapy (SBRT) for treatment of metastatic sarcoma, an attractive non-invasive intervention with potential for lower rates of adverse events than surgery. Current data are limited to retrospective analyses. This study analyzed 2-year local control and overall survival and adverse events in patients prospectively treated with SBRT to pulmonary sarcoma metastases. METHODS: Patients prospectively treated with SBRT to the lung for biopsy-proven metastatic sarcoma at a single institution from 2010 to 2022 were included. SBRT dose/fractionation treatment regimens ranged from 34 to 54 Gy in 1-10 fractions using photons. Local recurrence, local progression-free survival (LPFS) and overall survival (OS) were calculated from the end of SBRT. Univariable analysis (UVA) was performed using the log-rank test. Multivariable analysis (MVA) was performed using the Cox proportional hazards model. Adverse events due to SBRT were graded based on the Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: Eighteen patients with metastatic sarcoma were treated to 26 pulmonary metastases. The median local progression-free survival was not met. The median overall survival was not met. The local control rate at 2 years was 96%. 2-year LPFS was 95.5% and OS was 74%. Three patients (16.7%) developed grade 1 adverse events from SBRT. There were no adverse events attributed to radiation that were grade 2 or higher. CONCLUSION: We report prospective data demonstrating that SBRT for sarcoma pulmonary metastases affords a high rate of local control and low toxicity, consistent with prior sarcoma SBRT retrospective data. This study adds to the wealth of information on SBRT in a radioresistant tumor. Though largely limited to retrospective reviews, current data indicate high rates of local control with favorable toxicity profiles. Therefore, SBRT for pulmonary sarcoma metastases may be considered for properly selected patients.

One-Stage Synovectomies Result in Improved Short-Term Outcomes Compared to Two-Stage Synovectomies of Diffuse-Type Tenosynovial Giant Cell Tumor (D-TGCT) of the Knee: A Multicenter, Retrospective, Cohort Study.

Diffuse-type tenosynovial giant cell tumors' (D-TGCTs) intra- and extra-articular expansion about the knee often necessitates an anterior and posterior surgical approach to facilitate an extensive synovectomy. There is no consensus on whether two-sided synovectomies should be performed in one or two stages. This retrospective study included 191 D-TGCT patients from nine sarcoma centers worldwide to compare the postoperative short-term outcomes between both treatments. Secondary outcomes were rates of radiological progression and subsequent treatments. Between 2000 and 2020, 117 patients underwent one-stage and 74 patients underwent two-stage synovectomies. The maximum range of motion achieved within one year postoperatively was similar (flexion 123-120°, p = 0.109; extension 0°, p = 0.093). Patients undergoing two-stage synovectomies stayed longer in the hospital (6 vs. 4 days, p < 0.0001). Complications occurred more often after two-stage synovectomies, although this was not statistically different (36% vs. 24%, p = 0.095). Patients treated with two-stage synovectomies exhibited more radiological progression and required subsequent treatments more often than patients treated with one-stage synovectomies (52% vs. 37%, p = 0.036) (54% vs. 34%, p = 0.007). In conclusion, D-TGCT of the knee requiring two-side synovectomies should be treated by one-stage synovectomies if feasible, since patients achieve a similar range of motion, do not have more complications, but stay for a shorter time in the hospital.

Outcome comparison between muscle and fasciocutaneous flaps after secondary orthopedic procedures.

Lower extremity wounds associated with fractures and bony defects often require secondary orthopedic procedures after flap coverage has been performed. In this study, we compare complications between muscle and fasciocutaneous flaps after secondary orthopedic procedures. A retrospective chart review study of all lower extremity soft tissue reconstructions by a single surgeon over seven years yielded a subgroup of patients who underwent secondary orthopedic procedures, including hardware removal, hardware revision, and bone grafting after flap reconstruction. Of 355 lower extremity, soft tissue reconstructions for orthopedic coverage performed in the time period studied, 102 patients underwent secondary orthopedic procedures after flap reconstruction. Of these, 54 received muscle flaps (52.94%), and 48 received fasciocutaneous flaps (47.06%). Using this subgroup of 102 patients, we compared muscle and fasciocutaneous flaps using three categories of wound complications following these secondary procedures: There were no superficial wounds requiring local wound care only in the muscle flap group (0%, n = 0) versus 4.17% (n = 2; p = 0.130) in the fasciocutaneous flap group. There were 2 lost flaps requiring surgical debridement and additional skin grafting in the muscle flaps group (3.70%) versus 2 (4.17%; p = 0.904) in the fasciocutaneous flap group. In the third category, flap loss requiring additional soft tissue reconstruction was 18.52% (n = 10) in the muscle group versus 2.08% (n = 1; p = 0.008) in the fasciocutaneous flap group. Our data support the existing literature indicating that fasciocutaneous flaps can tolerate secondary procedures better than muscle flaps and should initially be considered in patients with higher probability of needing additional orthopedic procedures after reconstruction.

Is 5 the New 25? Long-Term Oncologic Outcomes From a Phase II, Prospective, 5-Fraction Preoperative Radiation Therapy Trial in Patients With Localized Soft Tissue Sarcoma.

Purpose: Management of adult soft tissue sarcomas entails a multidisciplinary approach with surgery and radiation therapy with or without chemotherapy. The use of preoperative irradiation has been well established, and although conventional fractionation involves daily treatments over the course of 5 weeks, higher doses per fraction may be beneficial due to the radiobiologic profile of sarcoma. In this study we report long-term oncologic outcomes from a single-institution, phase II study evaluating a 5-fraction hypofractionated course of preoperative radiation. Methods and materials: Preoperative hypofractionated radiation therapy was administered to 35 Gy in 5 fractions every other day followed by resection 4 to 6 weeks later. If given, chemotherapy consisted of a doxorubicin-ifosfamide-based regimen delivered neoadjuvantly. The primary endpoint was local control. Additional survival and pathologic outcomes, including overall and distant metastasis-free survival, tumor, and treatment-related pathology, as well as acute and late toxicity were examined. Results: Thirty-two patients were enrolled in this prospective, single-arm phase II trial. At a median follow-up of 36.4 months (range, 3-56), no patient developed a local recurrence, and the 3-year overall and distant metastasis-free survival was 82.2% and 69%, respectively. Major acute postoperative wound complications occurred in 25% of patients. Grade 2 and 3 fibrosis occurred in 21.7% and 13% of patients, respectively. The 2-year median and mean Musculoskeletal Tumor Society score for all patients was 28 and 27.4, respectively. Conclusions: A condensed course of preoperative hypofractionated radiation therapy leads to excellent rates of local control and survival with acceptable toxicity profiles. Potential studies ideally with phase II or III randomized trials would help corroborate these findings and other preoperative hypofractionated results in soft tissue sarcomas.

Uranium-nitride chemistry: uranium-uranium electronic communication mediated by nitride bridges.

Treatment of [UIV(N3)(TrenTIPS)] (1, TrenTIPS = {N(CH2CH2NSiPri3)3}3-) with excess Li resulted in the isolation of [{UIV(µ-NLi2)(TrenTIPS)}2] (2), which exhibits a diuranium(IV) 'diamond-core' dinitride motif. Over-reduction of 1 produces [UIII(TrenTIPS)] (3), and together with known [{UV(µ-NLi)(TrenTIPS)}2] (4) an overall reduction sequence 1 → 4 → 2 → 3 is proposed. Attempts to produce an odd-electron nitride from 2 resulted in the formation of [{UIV(TrenTIPS)}2(µ-NH)(µ-NLi2)Li] (5). Use of heavier alkali metals did not result in the formation of analogues of 2, emphasising the role of the high charge-to-radius-ratio of lithium stabilising the charge build up at the nitride. Variable-temperature magnetic data for 2 and 5 reveal large low-temperature magnetic moments, suggesting doubly degenerate ground states, where the effective symmetry of the strong crystal field of the nitride dominates over the spin-orbit coupled nature of the ground multiplet of uranium(IV). Spin Hamiltonian modelling of the magnetic data for 2 and 5 suggest U⋯U anti-ferromagnetic coupling of -4.1 and -3.4 cm-1, respectively. The nature of the U⋯U electronic communication was probed computationally, revealing a borderline case where the prospect of direct uranium-uranium bonding was raised, but in-depth computational analysis reveals that if any uranium-uranium bonding is present it is weak, and instead the nitride centres dominate the mediation of U⋯U electronic communication. This highlights the importance of obtaining high-level ab initio insight when probing potential actinide-actinide electronic communication and bonding in weakly coupled systems. The computational analysis highlights analogies between the 'diamond-core' dinitride of 2 and matrix-isolated binary U2N2.

Supervised Machine Learning-Based Decision Support for Signal Validation Classification.

INTRODUCTION: Signal validation in pharmacovigilance is the process of evaluating data to decide whether evidence is sufficient to justify further assessment of a detected signal. During the signal validation process, safety experts in our organization are required to review signals of disproportionate reporting (SDRs) and classify them into one of six predefined categories. OBJECTIVE: This experiment explored the extent to which predictive machine learning (ML) models can support the decision making of safety experts by accurately identifying the most appropriate predefined signal validation category. METHODS: We extracted cumulative data for six medicinal products, consisting of historic SDR validations and Individual Case Safety Reports, from the company's safety database for training and testing of the ML model. We implemented a decision tree-based supervised multiclass classifier model termed Gradient Boosted Trees followed by a SHapley Additive exPlanations (SHAP) analysis to mitigate the "black box" effect of the ensemble model by identifying the key predicting features in the model. Following a retrospective analysis, a prospective experiment was conducted to test the model accuracy and user acceptance in a real-life setting. RESULTS: The prediction accuracy of our ML model ranged from 83 to 86% over 3 months for the six medicinal products. The applicability of the model was confirmed by the company's safety experts. Additionally, the systematic predictions provided valuable information to the safety experts and assisted them in reviewing the SDRs efficiently and consistently. CONCLUSIONS: This experiment demonstrated that it is possible to train a multiclass classification model to accurately predict signal validation categories for SDRs. More importantly, the transparency of the predictions provided by the SHAP analysis led to high acceptance by the safety experts.

Local Control of Cancers With Various Ablation Techniques.

Metastatic disease to the bone and soft tissue creates significant morbidity because of pain resulting in decreased functional status. Palliative chemotherapy and radiation therapy were historically the mainstays of pain reduction. Minimally invasive technologies such as image-guided ablation and cementoplasty have become common in interventional radiology. Advances in image guidance and ablation technologies have improved the multidisciplinary approach in the management of bone and soft-tissue disease. The minimally invasive nature of the interventions allows prompt initiation or continuation of chemotherapy and radiation therapy. These safe and efficacious procedures have improved patient quality of life by decreasing pain and improving function.

Multi-segment foot kinematics during gait following ankle arthroplasty.

Ankle arthritis is a debilitating disease marked by pain and limited function. Total ankle arthroplasty improves pain while preserving motion and offers an alternative to the traditional treatment of ankle fusion. Gait analysis and functional outcomes tools can provide an objective balanced analysis of ankle replacement for the treatment of ankle arthritis. Twenty-nine patients with end-stage ankle arthritis were evaluated before and after ankle arthroplasty. Multi-segment foot and ankle kinematics were assessed annually following surgery (average 3.5 years, range 1-6 years) using the Milwaukee Foot Model and a Vicon video motion analysis system. Functional outcomes (American Orthopedic Foot and Ankle Society [AOFAS] ankle/hindfoot scale, short form 36 [SF-36] questionnaire) and temporal-spatial parameters were also assessed. Kinematic results were compared to findings from a previously collected group of healthy ambulators. AOFAS and SF-36 mean scores improved postoperatively. Walking speed and stride length increased after surgery. There were significant improvements in tibial sagittal range of motion in terminal stance and hindfoot sagittal range of motion in preswing. Decreased external rotation of the tibia and increased external rotation of the hindfoot were noted throughout the gait cycle. Pain and function improved after ankle replacement as supported by better outcomes scores, increased temporal-spatial parameters, and significant improvement in tibial sagittal range of motion during terminal stance and hindfoot sagittal range of motion during preswing. While multi-segment foot kinematics were improved, they were not restored to control values. Statement of clinical significance: Total ankle arthroplasty does not fully normalize mutli-segment gait kinematics despite improved patient-reported outcomes and gait mechanics.

Resection Status Does Not Impact Recurrence in Well-Differentiated Liposarcoma of the Extremity.

BACKGROUND: Well-differentiated liposarcoma (WDLPS) is a low-grade soft tissue sarcoma with a propensity for local recurrence. The necessity of obtaining microscopically free surgical margins (R0) to minimize local recurrence is not clear. This study evaluates recurrence-free survival (RFS) of extremity WDLPS in relation to resection margin status. METHODS: A retrospective review of adult patients with primary extremity WDLPS at seven US institutions from 2000 to 2016 was performed. Patients with recurrent tumors or incomplete resection (R2) were excluded. Clinicopathologic factors were analyzed to assess impact on local RFS. RESULTS: 97 patients with primary extremity WDLPS were identified. The majority of patients had deep, lower extremity tumors. Mean tumor size was 18.2±8.9cm. Patients were treated with either radical (76.3%) or excisional (23.7%) resections; 64% had R0 and 36% had microscopically positive (R1) resection margins. Ten patients received radiation therapy with no difference in receipt of radiation between R0 vs R1 groups. Thirteen patients (13%) developed a local recurrence with no difference in RFS between R0 vs R1 resection. Five-year RFS was 59.5% for R0 vs 85.2% for R1. Only one patient died of disease after developing dedifferentiation and distant metastasis despite originally having an R0 resection. DISCUSSION: In this large multi-institutional study of surgical resection of extremity WDLPS, microscopically positive margins were not associated with an increased risk of recurrence. Positive microscopic margin resection for extremity WDLPS may yield similar rates of local control while avoiding a radical approach to obtain microscopically negative margins.

Preoperative Radiation Performed at a Nonsarcoma Center May Lead to Increased Wound Complications Following Resection in Patients With Soft Tissue Sarcomas.

OBJECTIVES: Preoperative radiation therapy (RT) followed by wide-local excision with or without chemotherapy is widely accepted as management for soft tissue sarcomas (STS). Although studies have demonstrated excellent local control with this technique, there can be significant morbidity with the development of wound complications. It has been shown that sarcoma resections performed at a high-volume center lead to improved survival and functional outcomes. It is unclear, however, if radiation performed in a high-volume center leads to improved outcomes especially related to morbidity. The goal of this study was to determine whether preoperative RT performed at an academic cancer center have lower rates of wound complication compared with RT performed in community cancer centers. MATERIALS AND METHODS: A total of 204 patients with STS were treated with preoperative RT±chemotherapy followed by limb-sparing resection. Of these, 150 patients had preoperative RT performed at an academic sarcoma center. wound complication were defined as those requiring secondary operations or prolonged wound care for 4 months following surgery. Predictors for wound complication were evaluated using a Fisher exact test for univariate analysis and logistic regression for multivariate analysis. RESULTS: The overall incidence of wound complication was 28.3%. Significant predictors for wound complication include tumor location and radiation delivered at a community hospital. The postoperative incidence of wound complication was 21% when the preoperative RT was performed at an academic cancer center versus 39% when performed at a community cancer center (P=0.009). On multivariate analysis, both tumor location (P=0.0012, 95% confidence interval: 0.03-0.45, odds ratio: 0.13) and RT performed at a community cancer center (P=0.02, 95% confidence interval: 1.13-4.48, odds ratio: 2.25) remained significant in correlation with postoperative wound complication. CONCLUSIONS: Preoperative RT performed at an academic cancer center led to lower rates of postoperative wound complication. This may support the recommendation that preoperative RT and resection of STS be performed at an experienced sarcoma center.

Impact of clinical research coordinators on research output in orthopedic surgery.

Aim: To describe the efficacy of clinical research coordinators (CRCs) in terms of research output among faculty, residents and medical students. Materials & methods: We analyzed and reviewed departmental research output from the 3 years prior to the hire of 3 CRCs compared with the 3 years following. Results: From 2014 to 2016, the department output was a total of 27 peer-reviewed publications, 16 oral presentations and 33 poster presentations. From 2017-2019 there was a 52% increase in publications (n = 41), 131% increase in oral presentations (n = 37) and a 61% increase in poster presentations (n = 53). Conclusion: The implementation of CRCs has markedly increased tangible research output and trainee involvement. This role may serve as a valuable model for other academic departments.

Minimally Invasive Stabilization with or without Ablation for Metastatic Periacetabular Tumors.

BACKGROUND: Metastatic bone disease in the periacetabular region represents a potentially devastating problem for patients. Surgical treatment can offer pain relief and restore function. We describe a series of patients treated with minimally invasive osteoplasty and screw fixation with or without ablation. METHODS: Thirty-eight patients with 16 different metastatic tumor subtypes were managed with osteoplasty and screw fixation with or without ablation at a single institution. A retrospective review was performed to determine functional outcomes with use of the 1993 Musculoskeletal Tumor Society (MSTS) score as well as changes in narcotic usage. RESULTS: MSTS scores improved for all patients following surgery. Narcotic usage decreased in >80% of patients. Approximately half of the operations were outpatient procedures. Complications were minimal, there were no delays in chemotherapy or radiation due to surgical wound concerns, and there were no surgery-related deaths. The mean duration of follow-up was 9 months, with a 39% survival rate at the time of writing. Six of the 12 patients who survived for >1 year required additional procedures at a mean of 12 months (range, 4 to 23 months). CONCLUSIONS: Treatment of periacetabular metastatic disease with minimally invasive stabilization with or without ablation provides pain relief and functional improvement with lower complication rates than previously reported open reconstruction techniques. The minimally invasive approach allows for rapid initiation of chemotherapy and radiation. Patients with particularly aggressive cancers that are poorly responsive to systemic therapies and radiation may have progression of disease and may require additional procedures. Conversion to total hip arthroplasty was uncomplicated, and the cement and screw constructs were retained, providing a stable base for the arthroplasty reconstruction. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Dipnictogen f-Element Chemistry: A Diphosphorus Uranium Complex.

The first isolation and structural characterization of an f-element dinitrogen complex was reported in 1988, but an f-element complex with the first heavier group 15 homologue diphosphorus has to date remained unknown. Here, we report the synthesis of a side-on bound diphosphorus complex of uranium(IV) using a 7λ3-(dimethylamino)phosphadibenzonorbornadiene-mediated P atom transfer approach. Experimental and computational characterization reveals that the diphosphorus ligand is activated to its dianionic (P2)2- form and that in-plane U-P π-bonding dominates the bonding of the U(µ-η2:η2-P2)U unit, which is supplemented by a weak U-P interaction of δ symmetry. A preliminary reactivity study demonstrates conversion of this diphosphorus complex to unprecedented uranium cyclo-P3 complexes, suggesting in situ generation of transient, reactive phosphido species.

Minimally Invasive Stabilization of Periacetabular Metastasis.

Metastatic bone disease to the pelvis can lead to lower quality of life and function secondary to pain. Historically, treatment was palliative with radiation therapy and chemotherapy used to reduce pain. The Harrington procedure and subsequent modifications improved pain and function. In the subset of patients with complications, this would delay potential life-prolonging interventions such as chemotherapy and radiation therapy. Percutaneous palliative pain procedures including ablation and cementoplasty have been developed by interventional radiology for pelvic lesions and have been shown to be safe and efficacious. Additionally, percutaneous methods of pelvic fracture fixation have been developed. Modern image guidance technologies have allowed an expanded multidisciplinary approach to pelvic metastatic disease in a minimally invasive fashion with combinations of ablation, internal fixation, and cementation to improve patient quality of life and outcomes with decreased morbidity and rapid return to radiation and systemic therapies.

Pelvis weight-bearing ability after minimally invasive stabilizations for periacetabular lesion.

Periacetabular metastatic lesions cause debilitating weight-bearing pain and pose a risk of pelvic pathologic fracture. Minimally invasive percutaneous stabilization is an alternative palliative therapy over extensive open reconstructive surgeries. This study aimed to investigate the biomechanical behaviors of three distinct techniques of percutaneous periacetabular stabilization. A total of 20 composite hemipelves custom-made to contain Harrington type III periacetabular lesion based on a patient's computed tomograpy scans were assigned to treatment groups of cementoplasty alone using polymethyl methacrylate (Cement), screw fixation alone using ischial and posterior-to-anterior screws (Screws), cement-augmented screws (Screws&Cement), and a control group (Untreated). All hemipelves were loaded in a mechanical test configuration mimicking a single-legged stance, and failure load, failure deformation, and construct stiffness were determined. In the experiments, Screws&Cement demonstrated the highest yield strength (4711 ± 362 N) and was 12% higher than Cement (4005 ± 304 N, p = 0.019), 125% higher than Screws (2097 ± 359 N, p < 0.0001), and 184% higher than Untreated (1658 ± 254 N, p < 0.0001). No significant difference in yield strength was found between Screws and Untreated. Screws&Cement also demonstrated the highest stiffness (1013 ± 92 N/mm), followed by Cement (893 ± 49 N/mm), and both groups were significantly stiffer than Screws (543 ± 114 N/mm, p < 0.0001) and Untreated (580 ± 91 N/mm, p < 0.0001 for Screws&Cement, and p = 0.0003 for Cement). This study demonstrated that a cement-augmented periacetabular reconstruction is an effective option for percutaneous treatment of Harrington III periacetabular metastatic lesion. The addition of pelvic screws over cementoplasty significantly improved the pelvis load-bearing strength. When large periacetabular lesions are present, augmented screw fixation appears to be the superior choice of treatment.

Neoadjuvant radiation improves margin-negative resection rates in extremity sarcoma but not survival.

BACKGROUND AND OBJECTIVES: Radiation improves limb salvage in extremity sarcomas. Timing of radiation therapy remains under investigation. We sought to evaluate the effects of neoadjuvant radiation (NAR) on surgery and survival of patients with extremity sarcomas. MATERIALS AND METHODS: A multi-institutional database was used to identify patients with extremity sarcomas undergoing surgical resection from 2000-2016. Patients were categorized by treatment strategy: surgery alone, adjuvant radiation (AR), or NAR. Survival, recurrence, limb salvage, and surgical margin status was analyzed. RESULTS: A total of 1483 patients were identified. Most patients receiving radiotherapy had high-grade tumors (82% NAR vs 81% AR vs 60% surgery; P < .001). The radiotherapy groups had more limb-sparing operations (98% AR vs 94% NAR vs 87% surgery; P < .001). NAR resulted in negative margin resections (90% NAR vs 79% surgery vs 75% AR; P < .0001). There were fewer local recurrences in the radiation groups (14% NAR vs 17% AR vs 27% surgery; P = .001). There was no difference in overall or recurrence-free survival between the three groups (OS, P = .132; RFS, P = .227). CONCLUSION: In this large study, radiotherapy improved limb salvage rates and decreased local recurrences. Receipt of NAR achieves more margin-negative resections however this did not improve local recurrence or survival rates over.