Complete tumor necrosis after neoadjuvant chemotherapy defines good responders in patients with Ewing sarcoma.

BACKGROUND: Survival in patients who have Ewing sarcoma is correlated with postchemotherapy response (tumor necrosis). This treatment response has been categorized as the response rate, similar to what has been used in osteosarcoma. There is controversy regarding whether this is appropriate or whether it should be a dichotomy of complete versus incomplete response, given how important a complete response is for in overall survival of patients with Ewing sarcoma. The purpose of this study was to evaluate the impact that the amount of chemotherapy-induced necrosis has on (1) overall survival, (2) local recurrence-free survival, (3) metastasis-free survival, and (4) event-free survival in patients with Ewing sarcoma. METHODS: In total, 427 patients who had Ewing sarcoma or tumors in the Ewing sarcoma family and received treatment with preoperative chemotherapy and surgery at 10 international institutions were included. Multivariate Cox proportional-hazards analyses were used to assess the associations between tumor necrosis and all four outcomes while controlling for clinical factors identified in bivariate analysis, including age, tumor volume, location, surgical margins, metastatic disease at presentation, and preoperative radiotherapy. RESULTS: Patients who had a complete (100%) tumor response to chemotherapy had increased overall survival (hazard ratio [HR], 0.26; 95% CI, 0.14-0.48; p < .01), recurrence-free survival (HR, 0.40; 95% CI, 0.20-0.82; p = .01), metastasis-free survival (HR, 0.27; 95% CI, 0.15-0.46; p ≤ .01), and event-free survival (HR, 0.26; 95% CI, 0.16-0.41; p ≤ .01) compared with patients who had a partial (0%-99%) response. CONCLUSIONS: Complete tumor necrosis should be the index parameter to grade response to treatment as satisfactory in patients with Ewing sarcoma. Any viable tumor in these patients after neoadjuvant treatment should be of oncologic concern. These findings can affect the design of new clinical trials and the risk-stratified application of conventional or novel treatments.

Giant cell-rich osteosarcoma: A match pair analysis of 11 new cases and literature review of 56 patients.

BACKGROUND: Limited remains known on giant cell-rich osteosarcoma (GCRO) with current studies being case reports or smaller series. This investigation compared GCRO and conventional osteoblastic osteosarcoma (OOS) with regard to demographics and survival. METHODS: An institutional tumor registry was used to identify 11 patients (six males) treated for GCRO. Mean age was 43 years. Staging showed American Joint Committee on Cancer (AJCC) stages IIA in four and IIB in seven patients. Mean follow-up was 14 years. Study initiatives were: (1) Comparison of demographics between GCRO and 167 OOS from our institutional registry, (2) Differences in survival between GCRO and 33 OOS case controls (based on sex and AJCC stage), as well as 10 OOS using an age-based propensity match, and (3) Summary of all GCRO cases reported in the literature. RESULTS: (1) Sex (p = 0.53), grading (p = 0.56), AJCC stage (p = 0.42), and chemotherapeutic response rate (p = 0.67) did not differ between groups. Age was significantly increased in GCRO (p = 0.001). (2) Case-control and propensity-matched groups revealed no difference in disease-free survival, local recurrence, and distant disease-free survival at 2 years (p > 0.05). (3) Mean age of 56 patients (50% males) reported in the literature was 26 years. After merging with our 11 cases, the 2-year disease-free survival was 66%. CONCLUSIONS: GCRO remains a rare disease with high short-term mortality. Although affecting older patients more than conventional osteosarcoma, GCRO should not be viewed as a predictor of survival compared to OOS.

What is the Value of Radiology Input During a Multidisciplinary Orthopaedic Oncology Conference?

BACKGROUND: Multidisciplinary orthopaedic oncology conferences are important in developing the treatment plan for patients with suspected orthopaedic bone and soft tissue tumors, involving physicians from several services. Past studies have shown the clinical value of these conferences; however, the impact of radiology input on the management plan and time cost for radiology to staff these conferences has not been fully studied. QUESTIONS/PURPOSES: (1) Does radiology input at multidisciplinary conference help guide clinical management and improve clinician confidence? (2) What is the time cost of radiology input for a multidisciplinary conference? METHODS: This prospective study was conducted from October 2020 to March 2022 at a tertiary academic center with a sarcoma center. A single data questionnaire for each patient was sent to one of three treating orthopaedic oncologists with 41, 19, and 5 years of experience after radiology discussion at a weekly multidisciplinary conference. A data questionnaire was completed by the treating orthopaedic oncologist for 48% (322 of 672) of patients, which refers to the proportion of those three oncologists' patients for which survey data were captured. A musculoskeletal radiology fellow and musculoskeletal fellowship-trained radiology attending physician provided radiology input at each multidisciplinary conference. The clinical plan (leave alone, follow-up imaging, follow-up clinically, recommend different imaging test, core needle biopsy, surgical excision or biopsy or fixation, or other) and change in clinical confidence before and after radiology input were documented. A second weekly data questionnaire was sent to the radiology fellow to estimate the time cost of radiology input for the multidisciplinary conference. RESULTS: In 29% (93 of 322) of patients, there was a change in the clinical plan after radiology input. Biopsy was canceled in 30% (24 of 80) of patients for whom biopsy was initially planned, and surgical excision was canceled in 24% (17 of 72) of patients in whom surgical excision was initially planned. In 21% (68 of 322) of patients, there were unreported imaging findings that affected clinical management; 13% (43 of 322) of patients had a missed finding, and 8% (25 of 322) of patients had imaging findings that were interpreted incorrectly. For confidence in the final treatment plan, 78% (251 of 322) of patients had an increase in clinical confidence by their treating orthopaedic oncologist after the multidisciplinary conference. Radiology fellows and attendings spent a mean of 4.2 and 1.5 hours, respectively, reviewing and presenting at a multidisciplinary conference each week. The annual combined prorated time cost for the radiology attending and fellow was estimated at USD 24,310 based on national median salary data for attendings and internal salary data for fellows. CONCLUSION: In a study taken at one tertiary-care oncology program, input from radiology attendings and fellows in the setting of a multidisciplinary conference helped to guide the final treatment plan, reduce procedures, and improve clinician confidence in the final treatment plan, at an annual time cost of USD 24,310. CLINICAL RELEVANCE: Multidisciplinary orthopaedic oncology conferences can lead to changes in management plans, and the time cost to the radiologists should be budgeted for by the radiology department or parent institution.

Distant migration of gluteal augmentation fat presenting as a soft tissue knee mass.

Gluteal augmentation with autologous fat grafting is an increasingly popular procedure. While complication rates are low, the clinical and imaging evaluation of the various complications can be challenging. We report a case of distal migration of a failed gluteal fat graft in a young female patient presenting as a soft tissue mass in the knee, mimicking a soft tissue sarcoma. Surgical resection of the migrated fat graft confirmed the diagnosis. The diagnosis was challenging as the patient was initially reluctant to disclose her surgical history due to perceived negative social stigmas related to cosmetic contouring procedures. This case highlights the imaging findings of a rare complication following autologous fat grafting for gluteal augmentation and the importance of obtaining a thorough medical history.

Epithelioid Sarcoma Presenting in the Thumb of a Child.

Epithelioid sarcoma (ES) is a high-grade, soft tissue tumor of mesenchymal origin that rarely occurs in children and is often misdiagnosed as a benign entity. We present the case of a 12-year-old girl with a delayed diagnosis of ES of the left thumb. Radiological examination showed possible calcinosis from inflammation or traumatic injury. However, histopathological and immunohistochemistry studies showed findings consistent with a diagnosis of ES. She was treated with amputation of the interphalangeal joint of the left thumb. This case highlights the clinical and pathologic correlation required for the appropriate diagnosis and treatment of patients with soft tissue masses.

Image-Guided Core Needle Biopsy of Adipocytic Tumors: Diagnostic Accuracy and Concordance With Final Surgical Pathology.

OBJECTIVE. Diagnostic accuracy of core needle biopsy (CNB) for adipocytic tumors can be low because of sampling error from these often large, heterogeneous lesions. The purpose of this study was to evaluate the diagnostic accuracy of image-guided CNB for various adipocytic tumors in comparison with excisional pathology. MATERIALS AND METHODS. Adipocytic tumors (n = 77) of all adult patients undergoing image-guided CNB and subsequent surgical excision of an adipocytic tumor at a tertiary referral center between 2005 and 2019 were studied. To determine concordance, we compared pathologic diagnoses based on CNB to the reference standard of pathologic diagnoses after surgical excision. Tumors were divided into three categories (benign lipomatous tumors [lipoma, lipoma variants, hibernomas], atypical lipomatous tumors [ALTs] or well-differentiated liposarcomas [WDLs], and higher grade liposarcomas [myxoid, dedifferentiated, pleomorphic]), and diagnostic accuracy was calculated for each category. RESULTS. In 73 of 77 adipocytic tumors (95%), diagnosis at CNB and diagnosis after excision were concordant. Accuracy of diagnosis was poorer for ALTs and WDLs than for the other two categories, and the difference was statistically significant (p < .002). For the 29 benign lipomatous tumors and the 27 higher-grade liposarcomas, diagnoses at CNB and after excision were concordant in all cases (100%). Seventeen of the 21 tumors (81%) diagnosed as ALTs or WDLs at CNB had a concordant diagnosis after excision; four of the 21 were upgraded (dedifferentiated liposarcoma, n = 3; myxoid liposarcoma, n = 1). CONCLUSION. CNB provides high diagnostic accuracy for adipocytic tumors, particularly for benign lipomatous tumors and higher grade liposarcomas. However, though still high at 81%, diagnostic accuracy of CNB is not as high for tumors diagnosed as ALTs or WDLs. Awareness of this limitation is important when determining management, particularly of cases of ALT or WDL for which surgery is not planned.

Verrucous Venous Malformation-Subcutaneous Variant.

BACKGROUND: Verrucous venous malformation (VVM), previously called "verrucous hemangioma," typically involves the dermis and the subcutaneous fat. We have encountered patients with VVM confined to the hypodermis. MATERIALS AND METHODS: During a nearly 20-year period, 13 patients, aged 2-17 years, presented with a subcutaneous mass in the limb without clinically obvious epidermal alterations. Consequently, operative excisions did not include the skin. RESULTS: Histopathologically, the specimens were composed of blood-filled channels with morphologic characteristics of capillaries and veins that infiltrated adipose tissue. Aggregates often formed nodules with variable fibrosis and a component of large and radially oriented vessels. A diagnosis of VVM was supported by endothelial immunopositivity for GLUT-1 (25%-75% immunopositive channels in 16/16 specimens); D2-40 (1%-25% channels in 14/15 specimens); and Prox-1 (1%-50% of channels in 14/16 specimens). A MAP3K3 mutation was identified by droplet digital PCR in 3 of the 6 specimens. CONCLUSIONS: Diagnosis of VVM in this uncommon location is challenging because of absence of epidermal changes and lack of dermal involvement. Imaging is not pathognomonic, and mimickers are many. Appropriate immunohistochemical stains and molecular analysis contribute to the correct diagnosis.

Sclerotherapy for Aneurysmal Bone Cysts: Scale for Response.

BACKGROUND: The objective of this study was to develop a response scale for aneurysmal bone cysts (ABCs) treated with sclerotherapy and determine its inter-rater reproducibility. METHODS: Patients treated with sclerotherapy for an ABC between 1993 and 2014 were identified. An attending orthopaedic surgeon and an attending interventional radiologist independently reviewed the radiographic series for each patient and determined response to treatment using a novel grading system. Pain scores were collected from each visit. Inter-rater reliability was assessed using the intraclass correlation coefficient (ICC). General estimating equations analysis was used to evaluate the relationship between radiographic and pain scores and outcome, to develop an algorithm for the study patient population. A receiver operating characteristic curve was constructed to evaluate the diagnostic performance of the radiographic and pain scores in identifying the necessity of further treatment. To quantify the diagnostic utility, the area under the receiver operating characteristic curve was estimated along with a 95% confidence interval (CI). RESULTS: The inter-rater reliability was excellent for magnetic resonance imaging (ICC=0.83; 95% CI=0.74-0.89) and good for computed tomography/x-ray (ICC=0.69; 95% CI=0.51-0.81). The radiographic and pain scores proved to be independent predictors of treatment (P<0.001 and 0.004, respectively). An algorithm to determine the predictive probability for treatment versus observation in the study population was developed and tested based on these assessments. The area under the receiver operating characteristic curve of 0.85 (95% CI=0.79-0.92) indicated the good diagnostic performance of the algorithm. CONCLUSIONS: This novel grading system for radiographic response to sclerotherapy treatment demonstrates excellent to good inter-rater reliability giving providers a platform for discussion among themselves and with patients/parents. When incorporated with an assessment of pain, a predictive algorithm shows how this information could be used to determine the next steps after sclerotherapy treatment. LEVEL OF EVIDENCE: Level IV-case series.

Oncological and Functional Outcomes in Joint-sparing Resections of the Proximal Femur for Malignant Primary Bone Tumors.

BACKGROUND: Joint-sparing resections (JSR) of the proximal femur allow for preservation of the proximal femoral growth plate and native hip joint, but whether this offers fewer complications or better function and longevity of the reconstruction remains unknown. In this study, we compared the functional outcomes of pediatric patients with bone sarcomas undergoing JSR of the proximal femur with intercalary allograft (ICA) reconstruction to those undergoing proximal femoral resections (PFR) with allograft-prosthetic composite (APC) reconstructions. METHODS: We retrospectively reviewed all patients undergoing JSR with ICA reconstruction and PFR with APC reconstructions between 1995 and 2013 at a tertiary pediatric referral center. Primary outcomes included major and minor complications and secondary outcomes included the need for a secondary procedure, presence of local or distant relapse, survival status, and the presence of pain and ambulatory status (limp, assistive device, highest level of function). We assessed differences in outcomes using the Fisher exact and Wilcoxon rank-sum tests. RESULTS: Eight patients underwent a JSR and ICA reconstruction, while 7 patients underwent a PFR with APC reconstruction. Median patient follow-up was 60.4 months (interquartile range: 36.8 to 112.9) Patients undergoing JSR and ICA reconstruction were younger than patients undergoing PFR with APC reconstruction (7.7 vs. 11.7 y, P=0.043); however, we found no other statistically significant differences in patient demographics. There were no statistically significant differences in primary or secondary outcomes between the study groups; however, patients who underwent JSR with ICA had more major complications (62.5% vs. 42.9%, P=0.29) and a lower rate of minor complications (25% vs. 28.6%, P=0.22). CONCLUSION: Treatment of proximal femoral bone sarcomas in pediatric and adolescent patients remains a challenging enterprise. JSR with ICA reconstruction in the proximal femur, when feasible, may provide a similar function and risk of intermediate-term major and minor complications when compared with PFR with APC reconstruction. Further long-term studies are required to determine the impact of the native femoral head retention with respect to revision rates. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Surgical Management of Fibroadipose Vascular Anomaly of the Lower Extremities.

BACKGROUND: Fibroadipose vascular anomaly (FAVA) is a recently-defined vascular malformation often involving the extremities and presenting in childhood. Patients may present to orthopaedic surgeons with pain, swelling, joint contractures, and leg length discrepancy. There is no established therapy or treatment paradigm. We report on outcomes following surgical excision for patients with this condition. METHODS: Between 2007 and 2016, all 35 patients that underwent excision of lower-extremity FAVA were retrospectively reviewed using a combination of medical records, radiologic findings, and telemedicine reviews. RESULTS: Mean age at initial presentation was 12.3±6.8 years. Mean follow-up from time of definitive diagnosis at our institution was 66 months (range: 12 to 161 mo). Mean follow-up after surgery was 35 months (range: 6 to 138 mo). Females were affected more than males (71% vs. 29%). The most common location of FAVA was in the calf (49%), followed by the thigh (40%). The most commonly involved muscle was gastrocnemius (29%), followed by the quadriceps (26%). At latest follow-up after surgery, there was an improvement in the proportion of patients with pain at rest (63% vs. 29%), pain with activity (100% vs. 60%), as well as analgesia use (94% vs. 37%). Fourteen patients (40%) had symptomatic residual disease or recurrence of FAVA requiring further treatment. Six patients (17%) required further surgery and 6 (17%) required further interventional radiologic procedures. Three patients (9%) required eventual amputation for intractable pain and loss of function. Lesions with direct nerve involvement were associated with persistent neuropathic symptoms at latest follow-up (P=0.002) as well as symptomatic residual disease and/or recurrence requiring further treatment (P=0.01). Seventeen patients (49%) had 19 preoperative joint contractures. Eighteen of the 19 contractures (95%) had sustained improvement at latest follow-up. CONCLUSIONS: In carefully selected patients, surgical excision of FAVA results in improvement of symptoms. However, symptomatic residual disease and/or recurrence are not uncommon. Direct nerve involvement is associated with a worse outcome. LEVEL OF EVIDENCE: Level IV-case series.

The Pediatric Toronto Extremity Salvage Score (pTESS): Validation of a Self-reported Functional Outcomes Tool for Children with Extremity Tumors.

BACKGROUND: The physical function of children with sarcoma after surgery has not been studied explicitly. This paucity of research is partly because of the lack of a sufficiently sensitive pediatric functional measure. The goal of this study was to establish and validate a standardized measure of physical function in pediatric patients with extremity tumors. QUESTIONS/PURPOSES: (1) What is the best format and content for new upper- and lower-extremity measures of physical function in the pediatric population? (2) Do the new measures exhibit floor and/or ceiling effects, internal consistency, and test-retest reliability? (3) Are the new measures valid? METHODS: In Phase 1, interviews with 17 consecutive children and adolescents with bone tumors were conducted to modify the format and content of draft versions of the pediatric Toronto Extremity Salvage Score (pTESS). In Phase 2, the pTESS was formally translated into French. In Phase 3, 122 participants between 7 and 17.9 years old with malignant or benign-aggressive bone tumors completed the limb-specific measure on two occasions. Older adolescents also completed the adult TESS. Floor and ceiling effects, internal consistency, test-retest reliability, and validity were evaluated. RESULTS: Feedback from interviews resulted in the removal, addition, and modification of draft items, and the pTESS-Leg and pTESS-Arm questionnaires were finalized. Both versions exhibited no floor or ceiling effects and high internal consistency (α > 0.92). The test-retest reliability was excellent for the pTESS-Leg (intraclass correlation coefficient [ICC] = 0.94; 95% CI, 0.90-0.97) and good for the pTESS-Arm (ICC = 0.86; 95% CI, 0.61-0.96). Known-group validity (ability to discriminate between groups) was demonstrated by lower mean pTESS-Leg scores for participants using gait aids or braces (mean = 68; SD = 21) than for those who did not (mean = 87; SD = 11; p < 0.001). There was no significant difference between pTESS arm scores among respondents using a brace (n = 5; mean = 73; SD = 11) and those without (n = 22; mean = 83; SD = 19; p = 0.13). To evaluate construct validity, we tested a priori hypotheses. The duration since chemotherapy correlated moderately with higher pTESS-Leg scores (r = 0.4; p < 0.001) but not with pTESS-Arm scores (r = 0.1; p = 0.80), and the duration since tumor resection correlated moderately with higher pTESS-Leg scores (r = 0.4; p < 0.001) but not pTESS-Arm scores (r = 0.2; p = 0.4). Higher VAS scores (that is, it was harder to do things) antecorrelated with both pTESS versions (pTESS-Leg: r = -0.7; p < 0.001; pTESS-Arm: r = -0.8; p < 0.001). To assess criterion validity, we compared the pTESS with the current "gold standard" (adult TESS). Among adolescents, strong correlations were observed between the TESS and pTESS-Leg (r = 0.97, p < 0.001) and pTESS-Arm (r = 0.9, p = 0.007). CONCLUSIONS: Both pTESS versions exhibited no floor or ceiling effects and had high internal consistency. The pTESS-Leg demonstrated excellent reliability and validity, and the pTESS-Arm demonstrated good reliability and reasonable validity. The pTESS is recommended for cross-sectional evaluation of self-reported physical function in pediatric patients with bone tumors. LEVEL OF EVIDENCE: Level II, outcome measurement development.

The use of neoadjuvant larotrectinib in the management of children with locally advanced TRK fusion sarcomas.

BACKGROUND: The highly selective oral tropomyosin receptor kinase (TRK) inhibitor larotrectinib has demonstrated significant activity in adult and pediatric TRK fusion cancers. In the current study, the authors describe the clinical course of children with locally advanced TRK fusion sarcoma who were treated preoperatively with larotrectinib and underwent subsequent surgical resection. METHODS: A total of 24 children were treated on a pediatric phase 1 trial of larotrectinib (ClinicalTrials.gov identifier NCT02637687). Five children who had a documented TRK fusion sarcoma and underwent surgical resection were included in the current analysis. Tumor response (Response Evaluation Criteria In Solid Tumors [RECIST] version 1.1) and surgical outcomes were collected prospectively. RESULTS: A total of 5 patients (median age, 2 years; range, 0.4-12 years) had locally advanced infantile fibrosarcoma (3 patients) or soft-tissue sarcoma (2 patients). Four patients had disease that was refractory to standard therapy. All 5 patients achieved a partial response to larotrectinib by version 1.1 of RECIST and underwent surgical resection after a median of 6 cycles (range, 4-9 cycles) of treatment. Surgical resections were R0 (negative resection margins with no tumor at the inked resection margin) in 3 patients, R1 (microscopic residual tumor at the resection margin) in 1 patient, and R2 (macroscopic residual tumor at the resection margin) in 1 patient. Three patients achieved complete (2 patients) or near-complete (>98% treatment effect; 1 patient) pathologic responses. These patients remained in follow-up and were no longer receiving larotrectinib for a minimum of 7 to 15 months postoperatively. Two patients had viable tumor at the time of surgical resection and positive resection margins and continued to receive adjuvant larotrectinib. No patients experienced postoperative complications or wound healing issues. CONCLUSIONS: Children with locally advanced TRK fusion sarcomas may proceed to surgical resection after treatment with the selective TRK inhibitor larotrectinib, thereby sparing them the potentially significant morbidity noted with current approaches. These results support the evaluation of larotrectinib as presurgical therapy in children with newly diagnosed TRK fusion sarcomas.

Safety of omitting routine bleeding tests prior to image-guided musculoskeletal core needle biopsy.

PURPOSE: To evaluate the safety of withholding preprocedure international normalized ratio (INR) and platelet testing in patients undergoing musculoskeletal (MSK) core needle biopsy (CNB). MATERIAL AND METHODS: Initially, a retrospective review of 1,162 consecutive patients undergoing MSK CNB with preprocedural INR and platelet testing was performed. Clinical (age, gender, bleeding disorder, liver disease, anticoagulation use, INR > 2, platelet count <50,000/ul) and biopsy factors (imaging modality, lesion type, biopsy needle gauge, number biopsy samples) were tested for association with bleeding complications. During the second phase, an additional 188 biopsies performed without preprocedural coagulation testing were studied. Categorical variables were compared using Chi-squared or Fisher's exact tests, continuous variables with a student t-test. Multivariate analysis was performed using logistic regression. RESULTS: In the first phase, there was a complication rate of 2.6%, 30/1162. Of the 11 clinical and biopsy factors, soft tissue lesions (p = 0.029) and lesions biopsied under ultrasound (p = 0.048) had a higher rate of bleeding than bone lesions or lesions biopsied under CT, respectively. Only three patients had an INR >2, 0.3% (3/1162) and only four patients had platelet count <50,000/ul, 0.3% (4/1162). No patient with a bleeding complication had an abnormal preprocedure bleeding test. In the second phase, there was a bleeding complication rate of 1.1% (2/188). CONCLUSION: Bleeding complications from MSK biopsy are low, even when preprocedure coagulation testing is omitted.

Predictors of soft-tissue complications and deep infection in allograft reconstruction of the proximal tibia.

BACKGROUND AND OBJECTIVES: Reconstruction of the proximal tibia after wide resection of malignant tumors in the pediatric population is very challenging. Advocates of allograft reconstruction argue as advantages bone preservation, biological reconstruction that facilitates reattachment of the extensor mechanism and other soft-tissue structures, delay of metallic prosthesis use and preservation of the distal femoral growth plate. However, complications are significant, infection being very common. METHODS: Under IRB-approved protocol, 32 patients (17 males, 15 females), 13 years old in average (2-20), who underwent 33 allograft reconstructions of the proximal tibia, were evaluated for the occurrence of soft-tissue complications and/or deep infection (infection affecting the allograft). Potential predictors of soft-tissue complications and deep infection, categorized as pre- and perioperative variables, were analyzed in relation to the risk for developing a soft-tissue complication or a deep infection. RESULTS: The prevalence of soft-tissue complications was 48% (16/33). However, we were not able to identify any significant predictors. The prevalence of deep (allograft) infection was 15% (5/33). Multivariate logistic regression determined higher BMI at the index surgical procedure and lower pre-operative WBC to be independent predictors of deep infection. For each unit of increase in BMI, the odds of deep infection increased by 40% (OR = 1.40; CI = 1.07-3.06; P < 0.05). For each one unit (1,000) of increase in the pre-operative white cell-count, the odds of deep infection decreased by 70% (OR = 0.30; 95%CI = 0.01-0.89; P < 0.05). Four of the five deep infections were in patients with soft-tissue complications, mainly wound dehiscence. However, wound dehiscence or soft-tissue complications were not predictive of deep infection. CONCLUSION: Soft-tissue complications are prevalent in allograft reconstruction of the proximal tibia. Prevention is important as these may progress to deep infection. Careful attention to nutritional (BMI) and immunological status may help in patient selection for allograft reconstruction. If allograft reconstruction is opted for, efforts should focus on optimization of these factors as they proved to be independent predictors of subsequent deep infection. J. Surg. Oncol. 2016;113:811-817. © 2016 Wiley Periodicals, Inc.

CT-based Structural Rigidity Analysis Is More Accurate Than Mirels Scoring for Fracture Prediction in Metastatic Femoral Lesions.

BACKGROUND: Controversy continues regarding the appropriate assessment of fracture risk in long bone lesions affected by disseminated malignancy. QUESTIONS/PURPOSES: The purpose of this ongoing Musculoskeletal Tumor Society-sponsored, multi-institutional prospective cross-sectional clinical study is to compare CT-based structural rigidity analysis (CTRA) with physician-derived Mirels scoring for predicting pathologic fracture in femoral bone lesions. We hypothesized CTRA would be superior to Mirels in predicting fracture risk within the first year based on (1) sensitivity, specificity, positive predictive value, and negative predictive value; (2) receiver operator characteristic (ROC) analysis; and (3) fracture prediction after controlling for potential confounding variables such as age and lesion size. METHODS: Consented patients with femoral metastatic lesions were assigned Mirels scores by the individual enrolling orthopaedic oncologist based on plain radiographs and then underwent CT scans of both femurs with a phantom of known density. The CTRA was then performed. Between 2004 and 2008, six study centers performed CTRA on 125 patients. The general indications for this test were femoral metastatic lesions potentially at risk of fracture. The enrolling physician was allowed the choice of prophylactic stabilization or nonsurgical treatment, and the local treating oncology team along with the patient made this decision. Of those 125 patients, 78 (62%) did not undergo prophylactic stabilization and had followup sufficient for inclusion, which was fracture through the lesion within 12 months of CTRA, death within 12 months of CTRA, or 12-month survival after CTRA without fracture, whereas 15 (12%) were lost to followup and could not be studied here. The mean patient age was 61 years (SD, 14 years). There were 46 women. Sixty-four of the lesions were located in the proximal femur, 13 were in the diaphysis, and four were distal. Osteolytic lesions prevailed (48 lesions) over mixed (31 lesions) and osteoblastic (15 lesions). The most common primary cancers were breast (25 lesions), lung (14 lesions), and myeloma (11 lesions). CTRA was compared with Mirels based on sensitivity/specificity analysis, ROC, and fracture prediction by multivariate analysis. For the CTRA, reduction greater than 35% in axial, bending, or torsional rigidities at the lesion was considered at risk for fracture, whereas a Mirels score of 9 or above, as suggested in the original manuscript, was used as the definition of impending fracture. RESULTS: CTRA provided higher sensitivity (100% versus 66.7%), specificity (60.6% versus 47.9%), positive predictive value (17.6% versus 9.8%), and negative predictive value (100% versus 94.4%) compared with the classic Mirels definition of impending fracture (≥ 9), although there was considerable overlap in the confidence intervals. ROC curve analysis found CTRA to be better than the Mirels score regardless of what Mirels score cutoff was used. After controlling for potential confounding variables including age, lesion size, and Mirels scores, multivariable logistic regression indicated that CTRA was a better predictor of fracture (likelihood ratio test = 10.49, p < 0.001). CONCLUSIONS: CT-based structural rigidity analysis is better than Mirels score in predicting femoral impending pathologic fracture. CTRA appears to provide a substantial advance in the accuracy of predicting pathological femur fracture over currently used clinical and radiographic criteria. LEVEL OF EVIDENCE: Level III, diagnostic study.

Frozen section versus gross examination for bone marrow margin assessment during sarcoma resection.

BACKGROUND: Complete resection is critical for local control of primary bone sarcomas. Intraoperative consultation, including frozen section of bone marrow margins, frequently is used to aid in this goal. QUESTIONS/PURPOSES: We therefore sought to determine (1) how often intraoperative frozen section of a bone marrow margin correlates with inspection of the gross split specimen and, in cases of a discrepancy, what clinical decision is made; and (2) how well each of these assessments agrees with the final pathologic assessment of a marrow margin. METHODS: One hundred ninety-five bone marrow margins from 142 patients (74 males, 68 females; mean age, 12.8 years) with primary sarcomas who underwent resection and had frozen section(s) performed on a bone marrow margin were analyzed. Agreement between frozen section interpretation and inspection of the split gross specimen was analyzed in their application to determine adequacy of the bone marrow margin intraoperatively. RESULTS: In 179 margins, the frozen section agreed with the gross inspection decision (95.6% negative agreement, 38.5% positive agreement). Decisions regarding further surgical action in all 16 instances of disagreement were based on inspection of the split gross specimen, and the frozen section was disregarded. In 195 of 195 margins, intraoperative decisions were made based on gross specimen inspection. Full pathologic examination confirmed negative final bone marrow margins in all patients. CONCLUSIONS: Frozen section is commonly redundant or disregarded for intraoperative surgical decisions, and it may be omitted, saving operative time and cost. Examination of split gross specimens appears an adequate adjunct to clinicoradiographic assessment to achieve negative margins in the current era of modern imaging and surgical techniques. LEVEL OF EVIDENCE: Level II, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Dual Mobility for Oncological Hip Reconstruction: Significantly Reduced Dislocation Rates at 5 years.

BACKGROUND: Although dual mobility total hip arthroplasty has become increasingly common in recent years, limited remains known on dual mobility in surgical oncology. This university-based investigation compared dislocation and revision rates of DMs, conventional total hip arthroplasty (THA), and hemiarthroplasties (HAs) for oncological hip reconstruction. METHODS: An institutional tumor registry was used to identify 221 patients undergoing 45 DMs, 67 conventional THAs, and 109 HAs, performed for 17 primary hip tumors and 204 hip metastases between 2010 and 2020. The median age at surgery was 65 years, and 52% were female. The mean follow-up was 2.5 years. Kaplan-Meier survivorship curves and log-rank tests were done to compare dislocation and revision rates among all 221 patients, after a one-to-one propensity match, based on age, sex, tumor type (metastasis, primary tumor), and tumor localization (femur, acetabulum). RESULTS: The 5-year survivorship free of dislocation was 98% in DMs, 66% in conventional THAs ( P = 0.03; all P values compared with DMs), and 97% among HAs ( P = 0.48). The 5-year survivorship free of revision was 69% in DMs, 62% in conventional THAs ( P = 0.68), and 92% in HAs ( P = 0.06). After propensity matching, the 5-year survivorship free of dislocation was 42% in 45 conventional THAs ( P = 0.027; compared with all 45 DMs) and 89% in 16 matched HAs ( P = 0.19; compared with 16 DMs with femoral involvement only). The 5-year survivorship free of revision was 40% in matched conventional THAs ( P = 0.91) and 100% in matched HAs ( P = 0.19). CONCLUSIONS: DMs showed markedly lower rates of dislocation than conventional THAs, with overall revision rates remaining comparable among different designs. DMs should be considered the option of choice for oncological hip reconstruction if compared with conventional THAs. HAs are a feasible alternative when encountering femoral disease involvement only. LEVEL OF EVIDENCE: III.