Early, precise, and safe clinical evaluation of the pharmacodynamic effects of novel agents in the intact human tumor microenvironment

Introduction: Drug development is systemically inefficient. Research and development costs for novel therapeutics average hundreds of millions to billions of dollars, with the overall likelihood of approval estimated to be as low as 6.7% for oncology drugs. Over half of these failures are due to a lack of drug efficacy. This pervasive and repeated low rate of success exemplifies how preclinical models fail to adequately replicate the complexity and heterogeneity of human cancer. Therefore, new methods of evaluation, early in the development trajectory, are essential both to rule-in and rule-out novel agents with more rigor and speed, but also to spare clinical trial patients from the potentially toxic sequelae (high risk) of testing investigational agents that have a low likelihood of producing a response (low benefit). Methods: The clinical in vivo oncology (CIVO®) platform was designed to change this drug development paradigm. CIVO precisely delivers microdose quantities of up to 8 drugs or combinations directly into patient tumors 4-96 h prior to planned surgical resection. Resected tissue is then analyzed for responses at each site of intratumoral drug exposure. Results: To date, CIVO has been used safely in 6 clinical trials, including 68 subjects, with 5 investigational and 17 approved agents. Resected tissues were analyzed initially using immunohistochemistry and in situ hybridization assays (115 biomarkers). As technology advanced, the platform was paired with spatial biology analysis platforms, to successfully track anti-neoplastic and immune-modulating activity of the injected agents in the intact tumor microenvironment. Discussion: Herein we provide a report of the use of CIVO technology in patients, a depiction of the robust analysis methods enabled by this platform, and a description of the operational and regulatory mechanisms used to deploy this approach in synergistic partnership with pharmaceutical partners. We further detail how use of the CIVO platform is a clinically safe and scientifically precise alternative or complement to preclinical efficacy modeling, with outputs that inform, streamline, and de-risk drug development.

Does "Hoarding" Impact Interview Distribution Among Orthopaedic Surgery Residency Applicants? A Modeling Study Based on a Large Database

BACKGROUND

"Interview hoarding" is commonly used to refer to the concentration of interview offers among a small number of high-performing residency applicants. Theoretically, if the same applicants interview at every program, fewer rank lists will be submitted than open residency positions, leading to a "match crisis" with unfilled positions after the match. There are no published studies we are aware of that describe the observed distribution of residency interview offers among orthopaedic surgery applicants or the potential impact of "hoarding" on that distribution.

QUESTIONS/PURPOSES

We examined the distribution of interview invitations extended to orthopaedic surgery residency applicants in the 2020 to 2021 and 2021 to 2022 application cycles. The change in the shape of the interview invitation distribution was the primary outcome for two central questions: (1) Does the interview offer distribution curve among orthopaedic surgery applicants change meaningfully from baseline with implementation of an interview cap (Model 1)? (2) What is the impact on the distribution of invitations with a reduction in the number of applicants in the field (Model 2)?

METHODS

This was a retrospective study of orthopaedic surgery interview invitations extended to applicants via the Thalamus interview management program during the 2020 to 2021 and 2021 to 2022 residency application cycles. The Thalamus database was chosen because it contains data on interview invitations for orthopaedic surgery residency positions and has the largest market share in orthopaedics compared with similar databases. Thalamus data represent 1565 applicants and 53 residency programs (90% and 25% of the national total, respectively) in 2021 to 2022 and 993 applicants and 46 programs (77% and 23%, respectively) in 2020 to 2021. It has been shown to contain a representative sample of orthopaedic residency programs. An interview cap (Model 1) was simulated by removing excess interviews held by applicants above the 75th and 95th percentiles, which were chosen to represent a formal cap and an informal cap, respectively. A reduction in the size of the applicant pool was similarly modeled by randomly removing 5% and 25% of applicants, chosen to simulate informal and formal application requirements, respectively. In both models, the excess interviews were redistributed among the remaining applicants.

RESULTS

Applicants received a mean of 1.8 ± 2.2 Thalamus interview invitations in 2020 to 2021 and 1.7 ± 2.4 invitations in 2021 to 2022, with no change to the overall distribution curve. A total of 39% (606 of 1565) of applicants received no Thalamus interview invitations in 2021 to 2022, 75% (1176 of 1565) received two or fewer, and < 1% (14 of 1565) of applicants received 10 or more invitations. Redistributing excess interviews held by the top 5% of applicants resulted in 2% (61 of 2651) of interviews being redistributed (Model 1). Removing 5% of the total applicant pool resulted in a redistribution of 3% (87 of 2651) of the interview invitations (Model 2).

CONCLUSION

Orthopaedic surgery interview data demonstrated an expected uneven distribution of interview invitations, with a small proportion of highly competitive applicants receiving a higher number of interview offers as well as a large group of applicants receiving no interview invitations in Thalamus. Concerns that "hoarding" would lead to a crisis resulting in many unmatched residency positions seemed unfounded, given the excess of applicants relative to positions and the minimal change in the distribution of interviews in the cap model.

CLINICAL RELEVANCE

Medical students applying to orthopaedic residency should seek individual advising to improve their individual odds of matching, while understanding that interview hoarding does not seem to alter the distribution of interviews. Program directors and medical students' advisors should be cognizant that a small proportion of applicants are broadly interviewed and may benefit from steps taken to ensure applicants have genuine interest in the program.

Arthroplasty for Treating Proximal Femur Metastatic Lesions May Be Associated with Lower Mortality Rates Compared to Intramedullary Nailing within the VA Healthcare System

Metastatic bony disease is a significant health issue, with approximately 700,000 new cases annually that tend to metastasize to bones. The proximal femur in the appendicular skeleton is commonly affected. Our study aimed to investigate mortality rates and hospital stay duration in patients with pathologic proximal femur fractures treated with either intramedullary nailing or arthroplasty within the Veterans Health Administration system. In total, 679 patients (265 arthroplasty, 414 intramedullary nails) were identified through ICD-9 and CPT codes from 30 September 2010 to 1 October 2015. Hospital stays were similar for both groups (arthroplasty: 10.5 days, intramedullary nails: 11 days, p = 0.1). Mortality was associated with increased age and Gagne comorbidity scores (p < 0.001). Arthroplasty showed a survival benefit in the log-rank test (p = 0.018), and this difference persisted in the multivariate analysis after adjusting for age and comorbidities, with a hazard ratio of 1.3. Our study reported evidence that arthroplasty is associated with increased patient survival even when accounting for age and comorbidities in treating metastatic disease of the proximal femur.

Pediatric and Adult Patients Have Similar Functional Improvement After Endoprosthetic Reconstruction of Lower-Extremity Tumors

BACKGROUND

Although the treatment of lower-extremity bone tumors is similar between adult and pediatric patients, differences in outcomes are unknown. Outcomes for lower-extremity oncologic reconstruction have been challenging to study because of the low incidence and heterogeneity in disease and patient characteristics. The PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) trial is the largest prospective data set assembled to date for patients with lower-extremity bone tumors and presents an opportunity to investigate differences in outcomes between these groups.

METHODS

Patient details were acquired from the prospectively collected PARITY trial database. The 1993 Musculoskeletal Tumor Society (MSTS-93) and Toronto Extremity Salvage Score (TESS) questionnaires were administered preoperatively and at 3, 6, and 12 months postoperatively. Continuous outcomes were compared between groups with use of the Student t test, and dichotomous outcomes were compared with use of the Pearson chi-square test.

RESULTS

A total of 150 pediatric and 447 adult patients were included. Pediatric patients were more likely than adult patients to have a primary bone tumor (146 of 150 compared with 287 of 447, respectively; p < 0.001) and to have received adjuvant chemotherapy (140 of 149 compared with 195 of 441, respectively; p < 0.001). Reoperation rates were not significantly different between age groups (45 of 105 pediatric patients compared with 106 of 341 adult patients; p ≤ 0.13). Pediatric patients had higher mean MSTS-93 scores (64.7 compared with 53.8 among adult patients; p < 0.001) and TESS (73.4 compared with 60.4 among adult patients; p < 0.001) at baseline, which continued to 1 year postoperatively (mean MSTS-93 score, 82.0 compared with 76.8 among adult patients; p = 0.02; mean TESS, 87.7 compared with 78.6 among adult patients; p < 0.001). Despite the differences in outcomes between cohorts, pediatric and adult patients demonstrated similar improvement in MSTS-93 scores (mean difference, 17.4 and 20.0, respectively; p = 0.48) and TESS (mean difference, 14.1 and 14.7, respectively; p = 0.83) from baseline to 1 year postoperatively.

CONCLUSIONS

Pediatric patients had significantly better functional outcomes than adult patients at nearly all of the included postoperative time points; however, pediatric and adult patients showed similar mean improvement in these outcomes at 1 year postoperatively. These findings may be utilized to help guide the postoperative expectations of patients undergoing oncologic reconstruction.

LEVEL OF EVIDENCE

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

Opioid Use in Surgical Management in Musculoskeletal Oncology

BACKGROUND

Opioid prescribing in the context of orthopaedic surgery has been recognized as having a critical role in the ongoing opioid epidemic. Given the negative consequences of chronic opioid use, great efforts have been made to reduce both preoperative and postoperative opioid prescribing and consumption in orthopaedic surgery. Musculoskeletal oncology patients represent a unique subset of patients, and there is a paucity of data evaluating perioperative opioid consumption and the risk for chronic use. The objective of the present study was to describe opioid consumption patterns and evaluate predictors of chronic opioid use in musculoskeletal oncology patients undergoing limb-salvage surgery and endoprosthetic reconstruction.

METHODS

The present study was a secondary analysis of the recently completed PARITY (Prophylactic Antibiotic Regimens in Tumor Surgery) trial and included musculoskeletal oncology patients undergoing lower-extremity endoprosthetic reconstruction. The primary outcome was the incidence of opioid consumption over the study period. A multivariate binomial logistic regression model was created to explore predictors of chronic opioid consumption at 1 year postoperatively.

RESULTS

Overall, 193 (33.6%) of 575 patients were consuming opioids preoperatively. Postoperatively, the number of patients consuming opioids was 82 (16.7%) of 492 at 3 months, 37 (8%) of 460 patients at 6 months, and 28 (6.6%) of 425 patients at 1 year. Of patients consuming opioids preoperatively, 12 (10.2%) of 118 had continued to consume opioids at 1 year postoperatively. The adjusted regression model found that only surgery for metastatic bone disease was predictive of chronic opioid use (odds ratio, 4.90; 95% confidence interval, 1.54 to 15.40; p = 0.007). Preoperative opioid consumption, older age, sex, longer surgical times, reoperation rates, and country of origin were not predictive of chronic use.

CONCLUSIONS

Despite a high prevalence of preoperative opioid use, an invasive surgical procedure, and a high rate of reoperation, few patients had continued to consume opioids at 1 year postoperatively. The presence of metastases was associated with chronic opioid use. These results are a substantial departure from the existing orthopaedic literature evaluating other patient populations, and they suggest that specific prescribing guidelines are warranted for musculoskeletal oncology patients.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Femoral Magnetic Lengthening After Distal Femur Endoprosthetic Reconstruction in a Pediatric Patient: A Case Report

CASE

A 10-year-old boy with osteosarcoma of the left distal femur underwent resection with compressive osseointegration endoprosthetic reconstruction, gradually resulting in a 4.5-cm leg-length difference with significant predicted progression. Two years after resection, he underwent right distal femur and proximal tibia epiphysiodesis and placement of a left femoral magnetic lengthening nail. At 2 years after lengthening and skeletal maturity, the patient has symmetric limb lengths, no pain, and returned to sports.

CONCLUSION

A magnetic lengthening nail with contralateral epiphysiodesis is a viable option for correcting limb-length discrepancy after distal femur endoprosthetic reconstruction in a pediatric patient.

Is the Addition of Anaerobic Coverage to Perioperative Antibiotic Prophylaxis During Soft Tissue Sarcoma Resection Associated With a Reduction in the Proportion of Wound Complications?

BACKGROUND

Wound complications are common after resection of soft tissue sarcomas, with published infection rates ranging from 10% to 35%. Multiple studies have reported on the atypical flora comprising these infections, which are often polymicrobial and contain anaerobic bacteria, and recent studies have noted the high prevalence of anaerobic bacterial infections after soft tissue sarcoma resection [ 26, 35 ]. Based on this, our institution changed clinical practice to include an antibiotic with anaerobic coverage in addition to the standard first-generation cephalosporin for prophylaxis during soft tissue sarcoma resections. The current study was undertaken to evaluate whether this change was associated with a change in major wound complications, and if the change should therefore be adopted for future patients.

QUESTIONS/PURPOSES

(1) After controlling for potentially confounding variables, was the broadening of the prophylactic antibiotic spectrum to cover anaerobic bacteria associated with a lower odds of major wound complications after soft tissue sarcoma resection? (2) Was the broadening of the prophylactic antibiotic spectrum to cover anaerobic bacteria associated with a lower odds of surgical site infections with polymicrobial or anaerobic infections after soft tissue sarcoma resection? (3) What are the factors associated with major wound complications after soft tissue sarcoma resection?

METHODS

We retrospectively identified 623 patients who underwent soft tissue sarcoma resection at a single center between January 2008 and January 2021 using procedural terminology codes. Of these, four (0.6%) pediatric patients were excluded, as were five (0.8%) patients with atypical lipomatous tumors and two (0.3%) patients with primary bone tumors; 5% (33 of 623) who were lost to follow-up, leaving 579 for final analysis. The prophylactic antibiotic regimen given at the resection and whether a wound complication occurred were recorded. Patients received the augmented regimen based on whether they underwent resection after the change in practice in July 2018. A total of 497 patients received a standard antibiotic regimen (usually a first-generation cephalosporin), and 82 patients received an augmented regimen with anaerobic coverage (most often metronidazole). Of the 579 patients, 53% (307) were male (53% [264 of 497] in the standard regimen and 52% [43 of 82] in the augmented regimen), and the mean age was 59 ± 17 years (59 ± 17 and 60 ±17 years in the standard and augmented groups, respectively). Wound complications were defined as any of the following within 120 days of the initial resection: formal wound debridement in the operating room, other interventions such as percutaneous drain placement, readmission for intravenous antibiotics, or deep wound packing for more than 120 days from the resection. Patients were considered to have a surgical site infection if positive cultures resulted from deep tissue cultures taken intraoperatively at the time of debridement. The proportion of patients with major wound complications was 26% (150 of 579); it was 27% (136 of 497) and 17% (14 of 82) in the standard and augmented antibiotic cohorts, respectively (p = 0.049). With the numbers we had, we could not document that the addition of antibiotics with anaerobic coverage was associated with lower odds of anaerobic (4% versus 6%; p = 0.51) or polymicrobial infections (9% versus 14%; p = 0.25). Patient, tumor, and treatment (surgical, radiotherapy, and chemotherapy) variables were collected to evaluate factors associated with overall infection and anaerobic or polymicrobial infection. Patient follow-up was 120 days to capture early wound complications. A multivariable analysis was performed for all variables found to be significant in the univariate analysis. A p value < 0.05 was used as the threshold for statistical significance for all analyses. No patients were found to have an adverse reaction to the augmented regimen, including allergic reactions or Clostridioides (formerly Clostridium) difficile infection.

RESULTS

After controlling for other potentially confounding factors such as neoadjuvant radiation, tumor size and anatomic location, as well as patient BMI, anaerobic coverage was associated with smaller odds of wound complications (OR 0.36 [95% confidence interval (CI) 0.18 to 0.68]; p = 0.003). Other factors associated with major wound complications were preoperative radiation (versus no preoperative radiation) (OR 2.66 [95% CI 1.72 to 4.15]; p < 0.001), increasing tumor size (OR 1.04 [95% CI 1.00 to 1.07]; p = 0.03), patient BMI (OR 1.07 [95% CI 1.04 to 1.11]; p < 0.001), and tumor in the distal upper extremity (versus proximal upper extremity, pelvis/groin/hip, and lower extremity) (OR 0.18 [95% CI 0.04 to 0.62]; p = 0.01).

CONCLUSION

The addition of anaerobic coverage to the standard prophylactic regimen during soft tissue sarcoma resection demonstrated an association with smaller odds of major wound complications and no documented adverse reactions. Treating physicians should consider these findings but note that they are preliminary, and that further work is needed to replicate them in a more controlled study design such as a prospective trial.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Survival and failure modes of the Compress® spindle and expandable distal femur endoprosthesis among pediatric patients: A multi‐institutional study

BACKGROUND

Expandable endoprostheses can be used to equalize limb length for pediatric patients requiring reconstruction following large bony oncologic resections. Outcomes of the Compress® Compliant Pre-Stress (CPS) spindle paired with an Orthopedic Salvage System expandable distal femur endoprosthesis have not been reported.

METHODS

We conducted a multi-institutional retrospective study of pediatric patients with distal femoral bone sarcomas reconstructed with the above endoprostheses. Statistical analysis utilized Kaplan-Meier survival technique and competing risk analysis.

RESULTS

Thirty-six patients were included from five institutions. Spindle survivorship was 86.3% (95% confidence interval [CI], 67.7-93.5) at 10 years. Two patients had a failure of osseointegration (5.7%), both within 12 months. Twenty-two (59%) patients had 70 lengthening procedures, with mean expansions of 3.2 cm (range: 1-9) over 3.4 surgeries. The expandable mechanism failed in eight patients with a cumulative incidence of 16.1% (95% CI, 5.6-31.5) at 5 years. Twenty-nine patients sustained International Society of Limb Salvage failures requiring 63 unplanned surgeries. Periprosthetic joint infection occurred in six patients (16.7%). Limb preservation rate was 91% at 10 years.

CONCLUSIONS

There is a high rate of osseointegration of the Compress® spindle among pediatric patients when coupled with an expandable implant. However, there is a high rate of expansion mechanism failure and prosthetic joint infections requiring revision surgery.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Abstract 3424: Deep mechanistic profiling of immune oncology (I-O) drug combinations in cancer patients with CIVO® intratumoral microdosing and NanoString GeoMx DSP

Despite over four thousand clinical trials investigating combinations of various anti-cancer agents with immune checkpoint inhibitors (CPI), few have demonstrated significant clinical improvement over CPI alone. This indicates a need for approaches that can guide development of complex (≥ 3 drug) I-O combination treatments by enabling far greater mechanistic understanding of response to drug exposure by components of the authentic tumor microenvironment (TME). Here we show how an approach based on two technologies, the Presage Comparative In Vivo Oncology (CIVO) Platform and the NanoString GeoMx Digital Spatial Profiler (GeoMx DSP), highlights drug synergies as well as mechanisms of resistance to drug exposure in the native and intact TME of cancer patients, providing a path to rapid identification of effective drug combinations. The CIVO platform enables trackable multiplexed intratumoral delivery of microdosed drugs, either as single agents or in combinations, allowing evaluation of the localized tumor response to drug candidates in the TME while capturing tumor heterogeneity and patient diversity. GeoMx DSP is a method for high-plex spatial profiling of mRNAs with rare-cell sensitivity. Combining these technologies in Phase 0 clinical studies in human soft tissue sarcoma patients we evaluated distinct tumor sites microdosed with either nivolumab (anti-PD1), aldesleukin (recombinant IL-2), the combination of nivolumab and aldesleukin, vehicle (no drug), or chemotherapy controls. Using the Nanostring Cancer Transcriptome Atlas we evaluated the effect of drug exposure on expression of over 1,800 genes simultaneously with spatial resolution across individual patient tumors. Synergistic elevation of multiple transcripts was observed at tumor sites exposed to the combination of aldesleukin and nivolumab. This included T-cell specific elevation of granzyme B, a classic biomarker of T-cell activation. Importantly, we show how events such as T-cell activation may be dampened by feedback loops involving immune suppressive responses including, but not limited to, elevation of IDO-1 in non-T-cell components of the TME. Results were observed across multiple patient tumors and were verified by conventional immuno-histochemistry or in situ hybridization. Performing these studies across different patients allows us to explore the inter-individual variation in drug responses. We believe this is an efficient and biologically relevant approach to better understanding feedback loops activated within the authentic TME and ultimately prioritizing drug combinations for clinical development.

Citation Format: Jason P. Frazier, Kenneth R. Gundle, Marc Grenley, Gloria Kung, Kimberly Sottero, Kirsten Anderson, Richard Klinghoffer, Jonathan M. Derry. Deep mechanistic profiling of immune oncology (I-O) drug combinations in cancer patients with CIVO® intratumoral microdosing and NanoString GeoMx DSP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3424.

Abstract CT216: A phase 0 master protocol utilizing a novel intratumoral microdosing approach for simultaneously evaluating multiple drugs and drug combinations in patients with solid tumors

Purpose/Objectives: Tumor responses to cancer treatments are highly context-specific and often involve complex interactions between the anti-cancer therapy, genetically diverse tumor cells, and a heterogeneous tumor microenvironment (TME). All preclinical models fall short in capturing this complexity. CIVO (Comparative In Vivo Oncology) is an intratumoral microdose injection research tool intended to bridge the translational gap between preclinical and clinical studies by enabling in situ assessment of up to 8 oncology drugs or drug combinations simultaneously within a patient’s tumor. The CIVO Phase 0 model was established under FDA’s exploratory IND guidelines for microdosing. A Master Protocol was then developed, enabling ongoing evaluation of multiple investigational drugs and combinations without a need for stand-alone new protocols. Each investigational drug or combination is specified as a substudy of the Master Protocol, thus reducing administrative burden to clinical site staff and creating an infrastructure to ensure quality data and oversight of patient safety. This is a multi-center, open-label Phase 0 Master Protocol designed to study the localized pharmacodynamics (PD) of anti-cancer therapies within the TME when administered intratumorally in microdose quantities via the CIVO device. The safety of intratumoral microdose administration via the CIVO device will also be evaluated.

Materials/Methods: Approximately 12 subjects are expected to be enrolled per substudy. All substudies will evaluate subjects ≥18 years with a diagnosis of solid tumors with scheduled surgical intervention. Eligible subjects have at least one lesion (primary or recurrent tumor or effaced metastatic lymph node) ≥2 cm in the shortest diameter that is surface accessible for CIVO injection. Each substudy will define the tumor type and specific eligibility criteria for enrollment. The study visits consist of screening, CIVO injection, surgical intervention, and two follow-up visits. All patients will be injected by the CIVO device containing microdose quantities of drugs specified in respective substudies. The CIVO device can be configured with 3, 5, or 8 needles and the device configuration will be assigned on a per-patient basis, dependent upon lesion size. Following surgical resection, the injected portion of the tumor will undergo central PD biomarker analysis. At the time of submission, the study is open for enrollment with 1 substudy enrolling Head and Neck Squamous Cell Carcinoma (HNSCC) patients and 1 substudy enrolling HNSCC or soft tissue sarcoma patients. The Master Protocol was established to efficiently add substudies and accommodate evaluation of a wider repertoire of new agents in order to continually inform and de-risk drug development via the CIVO platform.

Clinical trial information: NCT04541108.

Citation Format: Karthik Rajasekaran, Jason G. Newman, Robert G. Maki, Thomas J. Ow, Vikas Mehta, Kenneth R. Gundle, Daniel R. Clayburgh, Ryan J. Li, Mercedes Porosnicu, Cherie-Ann O. Nathan, Alice Tang, Beryl A. Hatton, Kimberly H. Sottero, Gloria Kung, Marc O. Grenley, Kirsten Anderson, Richard A. Klinghoffer. A phase 0 master protocol utilizing a novel intratumoral microdosing approach for simultaneously evaluating multiple drugs and drug combinations in patients with solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT216.

MRI-based 3-dimensional volumetric assessment of fatty infiltration and muscle atrophy in rotator cuff tears

BACKGROUND

The Goutallier and Warner Classification systems are useful in determining rotator cuff reparability. Data are limited on how accurately the scapular-Y view used in both systems reflects the 3-dimensional (3-D) changes in fatty infiltration (FI) and muscle atrophy (MA). Tendon retraction in the setting of a cuff tear may also influence the perception of these changes. This study's objectives were to (1) measure the 3-D volume of the supraspinatus muscle in intact rotator cuffs, and with varying magnitudes of retraction; (2) measure the 3-D volume of FI in the supraspinatus muscle in these conditions; and (3) determine the influence of tendon retraction on measured FI and MA using the Goutallier and Warner Classification Systems.

METHODS

Between August 2015 and February 2016, all shoulder magnetic resonance images (MRIs) at the Portland VA Medical Center were standardized to include the medial scapular border. MRIs and charts were reviewed for inclusion/exclusion criteria. Included MRIs were categorized into 4 groups based on rotator cuff retraction. Supraspinatus muscle and fossa were traced to create 3-D volumes. FI and MA were measured within the supraspinatus. The supraspinatus muscle was graded among 6 physicians using the Goutallier and Warner classification systems. These grades were compared to 3-D measured FI and MA. The influence of tendon retraction on the measured grades were also evaluated.

RESULTS

One hundred nine patients met inclusion/exclusion criteria. Ten MRIs for each group (N = 40) were included for image analysis. Supraspinatus volume tracings were highly reproducible and consistent between tracers. Supraspinatus muscle volumes decreased while global FI and MA increased with greater degrees of tendon retraction. In muscles with less than 10% global fat, fat concentrated in the lateral third of the muscle. In muscle with more than 10% global fat content, it distributed more diffusely throughout the muscle from medial to lateral. In comparing the scapular-Y to a medial cut, there was no consistent trend in FI whereas MA was more accurate at the medial cut.

CONCLUSION

Parasagittal imaging location did not significantly influence the Goutallier score; however, assessment of MA using the Warner score leads readers to perceive less MA medially regardless of the magnitude of tendon retraction. The pattern of FI within the supraspinatus muscle changes from a laterally based location around the muscle-tendon junction to a more diffuse, global infiltration pattern when the whole muscle fat content exceeds 10%.

Physical Examination Is Predictive of Cauda Equina Syndrome: MRI to Rule Out Diagnosis Is Unnecessary

STUDY DESIGN

Cross-sectional cohort study.

OBJECTIVES

Cauda equina syndrome (CES) is a neurologic emergency, and delay in diagnosis can result in irreversible impairment. Our purpose was to determine the value of physical examination in diagnosis of CES in patients complaining of bladder and/or bowel complications in the emergency department.

METHODS

Adult patients at one tertiary academic medical center that endorsed bowel/bladder dysfunction, underwent a lumbar magnetic resonance imaging (MRI), and received an orthopedic spine surgery consultation from 2008 to 2017 were included. Patients consulted for trauma or tumor were excluded. A chart and imaging review was performed to collect demographic, physical examination, and treatment data. Sensitivity, specificity, and negative and positive predictive values were calculated, and fast-and-frugal decision trees (FFTs) were generated using R.

RESULTS

Of 142 eligible patients, 10 were diagnosed with CES. The sensitivity and specificity of the exam findings were highest for bulbocavernosus reflex (BCR) (100% and 100%), followed by rectal tone (80% and 86%), postvoid residual bladder (80% and 59%), and perianal sensation (60% and 68%). The positive predictive value was high for BCR (100%), but low for other findings (13% to 31%). However, negative predictive values were consistently high for all examinations (96% to 100%). Two FFTs utilizing combinations of voluntary rectal tone, perianal sensation, and BCR resulted in no false negatives.

CONCLUSIONS

A combination of physical examination findings of lower sacral function is an effective means of ruling out CES and, with further study, may eliminate the need for MRI in many patients reporting back pain and bowel or bladder dysfunction.

An Unusual Presentation of Inflammatory Shoulder Arthritis Associated with Nivolumab: A Case Report

CASE

A 68-year-old woman with a history of stage IIIC (T3bN1bM0) melanoma with metastases to her right axilla status after 10 cycles of nivolumab presented with right shoulder pain. Radiographs showed a progressive erosive glenohumeral joint lesion. The workup was negative for metastasis and infection. Her clinical and radiographic findings were consistent with erosive arthritis. The patient underwent shoulder hemiarthroplasty and experienced substantial improvements.

CONCLUSION

This is an unusual case of inflammatory arthritis associated with nivolumab, an antiprogrammed cell death protein 1, and is an important reminder of the musculoskeletal toxicities associated with immunotherapies.

Primary Aortic Angiosarcoma: A Review of Two Cases Highlighting Unique Imaging and Clinical Characteristics

Angiosarcomas are rare vascular connective tissue tumors originating from the tunica intima, media, or adventitia and may arise in large vessels. Here two cases of primary angiosarcoma of the aorta are described that highlight initial manifestations and unique complications from diffuse arterial tumor emboli, which led to delayed cancer diagnosis. In patients with aortic lesions, imaging characteristics must be thoughtfully reconciled with clinical scenarios, particularly in patients with no additional evidence of atherosclerosis or vasculitis. Keywords: Oncology, Neoplasms-Primary, MR-Angiography, Aorta © RSNA, 2021.

Association of Preoperative Hemoglobin A1c and Body Mass Index with Wound Infection Rate in Spinal Surgery

BACKGROUND

The deleterious effect of diabetes mellitus on surgical outcomes is well documented for joint replacement surgery. We analyzed the large national US Department of Veterans Affairs (VA) database for patients who had undergone elective spinal surgery.

METHODS

We retrospectively searched the VA database and identified 174 520 spine cases.

RESULTS

There were 7766 (4.5%) wound infections and 49 271 (28%) had hemoglobin A1c (HbA1c) testing (range: 3.0-17.8) prior to surgery. In the preoperative HbA1c-checked group, there were 2941 (6.0% of 49 271) infections and in the without-preoperative HbA1c group, there were 4825 (3.9% of 125 249) infections. The distribution of infections was significantly different (χ² = 372.577, P < .0001) and suggests a 2.12% increase in the absolute risk of infection based on the presence of preoperative HbA1c testing, regardless of the result. Logistic regression revealed a preoperative HbA1c test was associated with an odds ratio of 1.435 for infection (confidence interval 1.367-1.505, P < .0001). In a separate model based on HbA1c levels, we found that HbA1c is a significant predictor of infection with an odds ratio of 1.042 (confidence interval 1.017-1.068, P = .0009) for each 1% increase in the test result. This analysis differs from using a strict cutoff value of HbA1c of 6.5%. Similar testing for body mass index and age yielded an odds ratio of 1.027 for each increase of 1 kg/m² and an odds ratio of 1.009 for each 1-year increase in age respectively.

CONCLUSIONS

Hemoglobin A1c testing, HgA1c value, body mass index, and age all contribute to the risk of wound infection after elective spine surgery in a large national VA population. These data can be used to estimate surgical risks and to aid in patient counseling about proposed spine surgery.

LEVEL OF EVIDENCE

4.

Thromboembolic risk in patients with lung cancer receiving systemic therapy

In this retrospective study, we investigated the influence of chemotherapy and immunotherapy on thromboembolic risk among United States Veterans with lung cancer during their first 6 months (180 days) following initiation of systemic therapy. Included patients received treatment with common front-line agents that were divided into four groups: chemotherapy alone, immunotherapy alone, combination of chemo- and immunotherapies, and molecularly targeted therapies (control group). The cohort experienced a 7·4% overall incidence of thrombosis, but the analysis demonstrated significantly different rates among the different groups. We explored models incorporating multiple confounding variables as well as the competing risk of death, and these results indicated that both chemo- and immunotherapies were associated with an increased incidence of thrombosis, either alone or combined, compared with the control group (7·56%, P = 2.2 × 10^-16 ; 10·2%, P = 2.2 × 10^-16 ; and 7·87%, P = 2.4 × 10^-14 respectively vs. 4·10%). The Khorana score was found to be associated with increased risk, as were vascular disease and metastases. We found an association between risk of thrombosis and the use of anticoagulation, accounting for several confounders, including history of thrombosis. Further study is warranted to better determine the drivers of thromboembolic risk and to identify ways to mitigate this risk for patients.

Is Reoperation Higher Than Expected after Below-the-knee Amputation? A Single-center Evaluation of Factors Associated with Reoperation at 1 Year

BACKGROUND

Below-the-knee amputation (BKA) is relatively common among patients with vascular disease, infection, trauma, or neoplastic disease. Many BKAs are performed in patients with incompletely treated medical comorbidities, and some are performed in patients with acute high-energy trauma or crush injuries, malignant neoplasm undergoing time-sensitive limb removal, and diabetes with active infection or sepsis. Consequently, revision is common. Prior studies of outcomes after BKA, including several based on the American College of Surgeons-National Surgical Quality Improvement Program (ACS-NSQIP) database, have follow-up periods that do not cover the entire at-risk period.

QUESTIONS/PURPOSES

(1) What is the survivorship free from unplanned reoperation within 1 year of BKA? (2) What patient characteristics are associated with reoperation within 1 year of BKA?

METHODS

We retrospectively studied all BKAs performed by the orthopaedic surgery service at a Level 1 trauma center from 2008 to 2018, as identified by Current Procedural Terminology (CPT) codes. Twenty-eight percent (38 of 138) underwent amputation as treatment for traumatic injury, 57% (79 of 138) for infection, and 15% (21 of 138) for malignancy. A total of 17% (23 of 138) had a final follow-up encounter before the 1-year study minimum, without differential loss to follow-up by surgical indication (p = 0.43) or hemoglobin A1c (p = 0.71). Median (range) follow-up was 570 days (6 to 3375). The primary outcome was survivorship from unplanned reoperation within 1 year of BKA index surgery or last planned reoperation, as determined by Kaplan-Meier estimation. Secondarily, we identified patient characteristics independently associated with reoperation within 1 year of BKA. Collected data included age, indication, BMI, diabetes, hemoglobin A1c level, closure method, and substance use. Unplanned reoperation was defined as irrigation and débridement, stump revision, or revision to a higher-level amputation; this did not include planned reoperations for BKAs closed in a staged manner. Factors associated with reoperation were determined using multivariate logistic regression analyses. All endpoints and variables related to patients and their surgical procedures were extracted from electronic medical records by someone other than the operating surgeon.

RESULTS

Using Kaplan-Meier estimation, 38% of patients (95% confidence interval 29 to 46) who underwent BKA had an unplanned reoperation within 1 year of their index surgery. Twelve percent of patients (95% CI 7 to 17) who underwent BKA did not reach 30 days with the limb survivorship free from unplanned reoperation. The median (range) time between the initial surgery and reoperation was 54 days (6 to 315). After controlling for potential confounding variables like age, gender, platelet count, albumin, and the reason for undergoing amputation, a hemoglobin A1c level greater than 8.1% (relative to A1c ≤ 8.1%) was the only variable independently associated with increased odds of reoperation (odds ratio 4.6 [95% CI 1.3 to 18.1]; p = 0.02).

CONCLUSION

BKA carries a higher risk for reoperation than currently reported in studies that use 30-day postoperative follow-up periods. Clinicians should critically assess whether BKA is necessary, especially in patients with uncontrolled diabetes assessed by hyperglycemia. Before planned BKA, patients should have documented glycemic control to minimize the odds of reoperation. Because many of this study's limitations were due to its retrospective single center design, we recommend that future work cover a clinically appropriate surveillance period using a larger cohort such as a national database and/or employ a prospective design.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Compressive osseointegration for endoprosthetic reconstruction

This review summarizes the biomechanical concepts, clinical outcomes and limitations of compressive osseointegration fixation for endoprosthetic reconstruction. Compressive osseointe - gration establishes stable fixation and integration through a novel mechanism; a Belleville washer system within the spindle applies 400-800 PSI force at the boneimplant interface. Compressive osseointegration can be used whenever standard endoprosthetic reconstruction is indicated. However, its mode of fixation allows for a shorter spindle that is less limited by the length of remaining cortical bone. Most often compressive osseointegration is used in the distal femur, proximal femur, proximal tibia, and humerus but these devices have been customized for use in less traditional locations. Aseptic mechanical failure occurs earlier than with standard endoprosthetic reconstruction, most often within the first two years. Compressive osseointegration has repeatedly been proven to be non-inferior to standard endoprosthetic reconstruction in terms of aseptic mechanical failure. No demographic, device specific, oncologic variables have been found to be associated with increased risk of aseptic mechanical failure. While multiple radiographic parameters are used to assess for aseptic mechanical failure, no suitable method of evaluation exists. The underlying pathology associated with aseptic mechanical failure demonstrates avascular bone necrosis. This is in comparison to the bone hypertrophy and ingrowth at the boneprosthetic interface that seals the endosteal canal, preventing aseptic loosening.

Low-grade Osteosarcomatous Dedifferentiation of an Atypical Lipomatous Tumor in a Pediatric Patient

Atypical and malignant lipomatous tumors are infrequent in the pediatric population. Within this uncommon cohort, the morphologically and genetically related spectrum of atypical lipomatous tumor/well-differentiated liposarcoma/dedifferentiated liposarcoma (ALT/WDL/DDLS) is markedly rare. Their shared characteristic molecular aberration is a genomic amplicon of a region of chromosome 12q, including the oncogenes MDM2 and CDK4. We present an unusual case of a pediatric patient with an ALT, with recurrence after 2 years in the form of a bone-forming mass, radiologically and pathologically mimicking parosteal osteosarcoma, a tumor also molecularly characterized by amplification of MDM2 and CDK4. However, with ample histologic sampling, a single focus of lipogenic differentiation was identified, thus representing the first near complete low-grade osteosarcomatous dedififferentation reported within ALT/WDL/DDLS and the first ever in pediatric patient. The case serves a reminder of a diagnosis differential and pitfalls within MDM2-amplified tumors.

Multiplexed Evaluation of Microdosed Antineoplastic Agents In Situ in the Tumor Microenvironment of Patients with Soft Tissue Sarcoma

PURPOSE

A persistent issue in cancer drug development is the discordance between robust antitumor drug activity observed in laboratory models and the limited benefit frequently observed when patients are treated with the same agents in clinical trials. Difficulties in accurately modeling the complexities of human tumors may underlie this problem. To address this issue, we developed Comparative In Vivo Oncology (CIVO), which enables in situ investigation of multiple microdosed drugs simultaneously in a patient's tumor. This study was designed to test CIVO's safety and feasibility in patients with soft tissue sarcoma (STS).

PATIENTS AND METHODS

We conducted a single arm, prospective, 13-patient pilot study. Patients scheduled for incisional biopsy or tumor resection were CIVO-injected 1 to 3 days prior to surgery. Saline or microdoses of anticancer agents were percutaneously injected into the tumor in a columnar fashion through each of eight needles. Following excision, drug responses were evaluated in the injected tissue.

RESULTS

The primary objective was met, establishing CIVO's feasibility and safety. Device-related adverse events were limited to transient grade 1 nonserious events. In addition, biomarker evaluation of localized tumor response to CIVO microinjected drugs by IHC or with NanoString GeoMx Digital Spatial Profiler demonstrated consistency with known mechanisms of action of each drug, impact on the tumor microenvironment, and historic clinical activity.

CONCLUSIONS

These results are an advance toward use of CIVO as a translational research tool for early evaluation of investigational agents and drug combinations in a novel approach to phase 0 trials.See related commentary by Sleijfer and Lolkema, p. 3897.

Radiographic parameter-driven decision tree reliably predicts aseptic mechanical failure of compressive osseointegration fixation

Background and purpose - Compressive osseointegration fixation is an alternative to intramedullary fixation for endoprosthetic reconstruction. Mechanical failure of compressive osseointegration presents differently on radiographs than stemmed implants, therefore we aimed to develop a reliable radiographic method to determine stable integration.Patients and methods - 8 reviewers evaluated 11 radiographic parameters from 29 patients twice, 2 months apart. Interclass correlation coefficients (ICCs) were used to assess test-retest and inter-rater reliability. We constructed a fast and frugal decision tree using radiographic parameters with substantial test-retest agreement, and then tested using radiographs from a new cohort of 49 patients. The model's predictions were compared with clinical outcomes and a confusion matrix was generated.Results - 6 of 8 reviewers had non-significant intra-rater ICCs for ≥ one parameter; all inter-rater ICCs were highly reliable (p < 0.001). Change in length between the top of the spindle sleeve and bottom of the anchor plug (ICC 0.98), bone cortex hypertrophy (ICC 0.86), and bone pin hypertrophy (ICC 0.81) were used to create the decision tree. The sensitivity and specificity of the training cohort were 100% (95% CI 52-100) and 87% (CI 74-94) respectively. The decision tree demonstrated 100% (CI 40-100) sensitivity and 89% (CI 75-96) specificity with the test cohort.Interpretation - A stable spindle length and at least 3 cortices with bone hypertrophy at the implant interface predicts stable osseointegration; failure is predicted in the absence of bone hypertrophy at the implant interface if the pin sites show hypertrophy. Thus, our decision tree can guide clinicians as they follow patients with compressive osseo-integration implants.

Oncology Patients Are High Cost Outliers in Total Joint Replacement Bundled Payment Systems

BACKGROUND

In 2016, the Centers for Medicare and Medicaid Services began its first mandatory bundled payment program, the Comprehensive Care for Joint Replacement (CJR) model, which covers a 90-day episode of care. This study determined whether oncology patients enrolled in the CJR bundle incur higher hospital costs than patients with osteoarthritis (OA).

METHODS

A retrospective review of all patients enrolled in the CJR bundled payments system from April 1, 2016 to June 31, 2018 at a single academic medical center was conducted. To determine whether tumor patients had higher total episode costs, this group was compared to patients diagnosed with OA using a 2-tailed t-test. To adjust for moderators of total hospital costs, we used generalized linear regression with a log-link, including multiple variables abstracted from chart review.

RESULTS

Three hundred fourteen patients met inclusion criteria (12 primary or metastatic tumors, 302 OA). Fifty-eight percent of tumor patients were over the target price vs 16% of OA patients. The mean tumor patient had $40,862 for total internal hospital costs compared to $16,356 in the OA group (P < .001). Length of stay was greater in the tumor group (6.75 vs 2.0 days, P < .001). A greater percentage of tumor patients were discharged to a skilled nursing facility (67% vs 27%, P = .006) with significantly higher skilled nursing facility episode costs ($18,852 vs $7731, P = .04). With adjustment for fracture status, tumor patients were 5.36 times more likely to exceed the CJR target price than OA patients (risk ratio 5.36, confidence interval 3.44-8.35, P < .001) and 50 times more likely to be outliers over the regional threshold than OA patients (risk ratio 50.33, confidence interval 16.33-155.19, P < .001).

CONCLUSION

Oncology patients enrolled in the CJR bundled payment model incur significantly higher costs and have higher cost variability than patients with OA. We recommend that oncology patients be excluded from the CJR bundle.

Abstract 2155: High-plex spatial profiling analysis of multidrug CIVO microdose studies in cancer patients

Background: CIVO microdosing studies performed in patient tumors in situ allow drug developers to assess localized tumor and microenvironment responses to multiple agents without having to expose patients to high systemic drug levels. By concentrating microdoses of multiple different drugs within a living tumor in situ, it is possible to compare tumor and immune responses in spatially resolved regions of the same tumor. This type of early phase (Phase 0) clinical study represents a new path for drug developers to gain insight into drug efficacy, tumor associated immune cell modulation, biomarker discovery and validation, and microenvironment interactions for new drugs earlier in the drug development process. Traditionally, analysis of FFPE samples from these microdosing studies involve routine immunohistochemistry, immunofluorescence, and in situ assays that reveal changes in protein and RNA expression. These assays offer tissue wide protein and gene expression information but have limited multiplexing capabilities and dynamic range, as well as rapidly consume precious trial samples. Novel technologies such as NanoString’s GeoMxTM Digital Spatial Profiler (DSP) enable high-plex spatially resolved analysis of proteins and RNA transcripts in single FFPE tissue sections. In this proof of principle study, we utilized GeoMxTM Digital Spatial Profiler for protein and RNA expression on single FFPE sections from patient sarcoma tumors that were microdosed with multiple FDA approved drugs.

Methods: Single FFPE sections from microdosed patient tumor samples were IF stained for DNA and CD3 and whole slide imaged. 600-micron and 100-micron diameter regions of interests (ROIs) were selected for DSP analysis within drug and control microinjection sites. Imaging and barcode counts were performed using GeoMxTM DSP and nCounter systems.

Results: DSP protein analysis highlighted phospho-S6 and phospho-ERK upregulation in response to doxorubicin compared to vehicle site. Additionally, ROIs sampled along the doxorubicin exposure gradient showed a dose-dependent reduction of phosphorylation of both S6 and ERK proteins. DSP RNA analysis revealed drug specific transcript regulation of multiple genes in microdosed tumors, including upregulation of chemokines CXCL9 and CXCL10 at sites of doxorubicin and aldesleukin injection but not to other chemotherapy agents.

Conclusions: Early phase CIVO microdosing studies combined with high-plex DSP opens the door to generating multi-omics data for multiple microdosed drugs within small patient studies. Analysis of protein and RNA expression using DSP enabled collection of targeted region of interest high density data from single FFPE sections, conserving precious patient biopsy samples. Through continued expansion of the GeoMxTM DSP analyte panels, collecting an ever-increasing depth of protein and gene expression data is possible in Phase 0 CIVO microdosing studies.

Citation Format: Gary B. Deutsch, Seth M. Pollack, Matthew J. Thompson, Kenneth R. Gundle, Jessica A. Bertout, Jason P. Frazier, Emily Beirne, Marc O. Grenley, JingJing Gong, Yan Liang, Joseph M. Beechem, Richard A. Klinghoffer, Robert G. Maki. High-plex spatial profiling analysis of multidrug CIVO microdose studies in cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2155.

Evaluation of Endoscopic Iliopsoas Tenotomy for Treatment of Iliopsoas Impingement After Total Hip Arthroplasty

BACKGROUND

Iliopsoas impingement after total hip arthroplasty (THA) occurs in up to 4.3% of patients resulting in functional groin pain. Operative treatment historically has included open iliopsoas tenotomy or acetabulum revision. We present a large single surgeon series of patients treated with endoscopic iliopsoas tenotomy for iliopsoas impingement after THA to evaluate the effectiveness and risks.

METHODS

A consecutive series of 60 patients with iliopsoas impingement after THA treated with endoscopic iliopsoas tenotomy was retrospectively evaluated. Outcomes assessed were resolution of pain, change in Hip Outcome Score (HOS), and complications. Radiographs were reviewed by a musculoskeletal radiologist to evaluate component positioning and to compare with a control cohort.

RESULTS

At last follow-up (mean 5.5 months), 93.3% of patients had resolution of pain. The HOS activities of daily living (ADL) subscale mean was 57.5 (range 10.9-89.3, standard deviation [SD] 18.8) preoperatively and 71.6 (range 14.1-100, SD 26.1) postoperatively (P = .005). The HOS sports subscale mean was 37.3 (range 0-83.3, SD 24.0) preoperatively and 58.1 (range 0-100, SD 33.2) postoperatively (P = .002). One complication was reported, a postoperative hematoma managed conservatively. Body mass index and increased offset were associated with iliopsoas symptoms after THA in this series.

CONCLUSION

Endoscopic iliopsoas tenotomy after THA had a 93.3% resolution of pain, clinically important improvements in HOS, and low rate of complications. Endoscopic tenotomy should be considered as a treatment option in patients with iliopsoas impingement after THA.

Safety and efficacy of high-dose methotrexate for osteosarcoma in adolescents compared with young adults

Background

Doxorubicin, cisplatin, and high‐dose methotrexate (HDMTX) are the backbone of pediatric osteosarcoma treatment. However, due to toxicity concerns and the lack of data regarding efficacy in adults, high‐dose methotrexate is rarely used in the adult population.

Methods

This single‐center retrospective study examined 33 patients who received HDMTX (12 g/m², maximum 20 g) for the treatment of osteosarcoma at Oregon Health and Science University (OHSU) from 2011 to 2017. Time to serum methotrexate level ≤0.1 µmol/L was the primary outcome. Secondary outcomes included number of HDMTX doses received, methotrexate‐related toxicities, and disease outcomes including histologic response at resection and metastasis‐free survival.

Results

Median age was 20 years [range 7‐38]; 14 patients ≤18 years old and 19 patients >18 years old. Median time to clearance for patients ≤18 years was 79 hours (range 63‐116) compared to 120 hours (range 77‐315) for patients >18 years (P < 0.001). No correlation between age and histologic response at resection was observed (P = 0.50), but there was a significant positive correlation between the number of HDMTX doses received before resection and histologic response (r = 0.49, P = 0.006). There was no significant difference in metastasis‐free survival between age groups, although a trend toward improved survival was noted for patients who received at least seven doses of HDMTX.

Conclusion

Age over 18 years correlates with delayed methotrexate clearance and fewer administered doses of methotrexate, without increased toxicity. The potential benefit of HDMTX in young adults with osteosarcoma may outweigh toxicity risks.

Treatment Modalities for Pathologic Fractures of the Proximal Femur Pertrochanteric Region: A Systematic Review and Meta-Analysis of Reoperation Rates

BACKGROUND

The proximal femur represents the most common site of metastatic bone disease in the appendicular skeleton, and associated pathologic pertrochanteric femur fractures contribute to cancer-related morbidity and mortality. Controversy exists as to whether these injuries are best managed with intramedullary nailing (IMN) or with arthroplasty.

METHODS

A systematic review of the literature was performed using a PubMed search following PRISMA guidelines to identify studies performed within the last 20 years regarding treatment of proximal femur metastatic lesions with either nailing or arthroplasty with a reported reoperation rate. Sixteen studies were selected for inclusion containing 1414 patients. Pooled estimates and 95% confidence intervals (CIs) for reoperation rates associated with IMN and endoprosthetic reconstruction (EPR) were separately calculated.

RESULTS

The pooled estimate for reoperation for IMN was a median of 9% (95% CI, 5%-14%) and the pooled estimate for reoperation for EPR was a median of 7% (95% CI, 5%-11%). Significant heterogeneity was present in studies reporting on both treatment modalities: for IMN, I² = 55%, and for EPR, I² = 51%.

CONCLUSION

This systematic literature review identified 16 eligible, nonrandomized, retrospective studies that reported on the results of surgical treatment for proximal femur metastatic disease. The pooled estimate of reoperation was similar between patients treated with IMN and EPR. Inconsistencies among follow-up and the study designs used limited evidence-based conclusions. As the oncologic care of patients with metastatic disease continues to evolve and improve, patient-specific needs must be carefully considered when selecting an optimal treatment strategy.

LEVEL OF EVIDENCE

Level III.

Analysis of Margin Classification Systems for Assessing the Risk of Local Recurrence After Soft Tissue Sarcoma Resection

Purpose To compare the ability of margin classification systems to determine local recurrence (LR) risk after soft tissue sarcoma (STS) resection. Methods Two thousand two hundred seventeen patients with nonmetastatic extremity and truncal STS treated with surgical resection and multidisciplinary consideration of perioperative radiotherapy were retrospectively reviewed. Margins were coded by residual tumor (R) classification (in which microscopic tumor at inked margin defines R1), the R+1mm classification (in which microscopic tumor within 1 mm of ink defines R1), and the Toronto Margin Context Classification (TMCC; in which positive margins are separated into planned close but positive at critical structures, positive after whoops re-excision, and inadvertent positive margins). Multivariate competing risk regression models were created. Results By R classification, LR rates at 10-year follow-up were 8%, 21%, and 44% in R0, R1, and R2, respectively. R+1mm classification resulted in increased R1 margins (726 v 278, P < .001), but led to decreased LR for R1 margins without changing R0 LR; for R0, the 10-year LR rate was 8% (range, 7% to 10%); for R1, the 10-year LR rate was 12% (10% to 15%) . The TMCC also showed various LR rates among its tiers ( P < .001). LR rates for positive margins on critical structures were not different from R0 at 10 years (11% v 8%, P = .18), whereas inadvertent positive margins had high LR (5-year, 28% [95% CI, 19% to 37%]; 10-year, 35% [95% CI, 25% to 46%]; P < .001). Conclusion The R classification identified three distinct risk levels for LR in STS. An R+1mm classification reduced LR differences between R1 and R0, suggesting that a negative but < 1-mm margin may be adequate with multidisciplinary treatment. The TMCC provides additional stratification of positive margins that may aid in surgical planning and patient education.

The role of postoperative radiation and coordination of care in patients with metastatic bone disease of the appendicular skeleton

Metastatic bone disease affects approximately 300,000 people in the United States, and the burden is rising. These patients experience significant morbidity and decreased survival. The management of these patients requires coordinated care among a multidisciplinary team of physicians, including orthopaedic surgeons. This article reviews the role of radiation therapy after orthopaedic stabilization of impending or realized pathologic extremity fractures. Orthopaedic surgeons have an opportunity to benefit patients with metastatic bone disease by referring them for consideration of post-operative radiation therapy. Further research into rates of referral and the effect on clinical outcomes in this population is needed.

Rapid Web-Based Platform for Assessment of Orthopedic Surgery Patient Care Milestones: A 2-Year Validation

OBJECTIVE

To determine the validity, feasibility, and responsiveness of a new web-based platform for rapid milestone-based evaluations of orthopedic surgery residents.

SETTING

Single academic medical center, including a trauma center and pediatrics tertiary hospital.

PARTICIPANTS

Forty residents (PG1-5) in an orthopedic residency program and their faculty evaluators.

METHODS

Residents and faculty were trained and supported in the use of a novel trainee-initiated web-based evaluation system. Residents were encouraged to use the system to track progress on patient care subcompetencies. Two years of prospectively collected data were reviewed from residents at an academic program. The primary outcome was Spearman's rank correlation between postgraduate year (PGY) and competency level achieved as a measure of validity. Secondary outcomes assessed feasibility, resident self-evaluation versus faculty evaluation, the distributions among subcompetencies, and responsiveness over time.

RESULTS

Between February 2014 and February 2016, 856 orthopedic surgery patient care subcompetency evaluations were completed (1.2 evaluations per day). Residents promptly requested feedback after a procedure (median = 0 days, interquartile range: 0-2), and faculty responded within 2 days in 51% (median = 2 days, interquartile range: 0-13). Primary outcome showed a correlation between PGY and competency level (r = 0.78, p < 0.001), with significant differences in competency among PGYs (p < 0.001 by Kruskal-Wallis rank sum test). Self-evaluations by residents substantially agreed with faculty-assigned competency level (weighted Cohen's κ = 0.72, p < 0.001). Resident classes beginning the study as PGY1, 2, and 3 separately demonstrated gains in competency over time (Spearman's rank correlation 0.39, 0.60, 0.59, respectively, each p < 0.001). There was significant variance in the number of evaluations submitted per subcompetency (median = 43, range: 6-113) and competency level assigned (p < 0.01).

CONCLUSIONS

Rapid tracking of trainee competency with milestone-based evaluations in a learner-centered mobile platform demonstrated validity, feasibility, and responsiveness. Next Accreditation System-mandated data may be efficiently collected and used for trainee and program self-study.

Intercalary allograft augmented with intramedullary cement and plate fixation is a reliable solution after resection of a diaphyseal tumour

AIMS

Intercalary allografts following resection of a primary diaphyseal tumour have high rates of complications and failures. At our institution intercalary allografts are augmented with intramedullary cement and fixed using compression plating. Our aim was to evaluate their long-term outcomes.

PATIENTS AND METHODS

A total of 46 patients underwent reconstruction with an intercalary allograft between 1989 and 2014. The patients had a mean age of 32.8 years (14 to 77). The most common diagnoses were osteosarcoma (n = 16) and chondrosarcoma (n = 9). The location of the tumours was in the femur in 21, the tibia in 16 and the humerus in nine. Function was assessed using the Musculoskeletal Tumor Society (MSTS) scoring system and the Toronto Extremity Salvage Score (TESS). The survival of the graft and the overall survival were assessed using the Kaplan-Meier method.

RESULTS

The median follow-up was 92 months (4 to 288). The mean MSTS 87 score was 29.1 (19 to 35), the mean MSTS 93 score was 82.2 (50 to 100) and the mean TESS score was 81.2 (43 to 100). Overall survival of the allograft was 84.8%. A total of 15 patients (33%) had a complication. Five allografts were revised for complications and one for local recurrence.

CONCLUSION

Intercalary allografts augmented with intramedullary cement and compression plate fixation provide a reliable and durable method of reconstruction after the excision of a primary diaphyseal bone tumour, with high levels of function and satisfaction. Cite this article: Bone Joint J 2017;99-B:973-8.

Increasing medical student exposure to musculoskeletal medicine: the initial impact of the Orthopaedic Surgery and Sports Medicine Interest Group

PURPOSE

To investigate the impact of the Orthopaedic Surgery and Sports Medicine Interest Group (OSSMIG) on medical student interest and confidence in core musculoskeletal (MSK) concepts through supplemental education and experiences at a single tertiary, academic institution.

METHODS

Medical student OSSMIG members at various levels of training were anonymously surveyed at the beginning and end of the 2014-2015 academic year.

RESULTS

Eighteen (N=18) medical student interest group members completed the survey. Significant improvement in their level of training was observed with regard to respondents' self-assessed competence and confidence in MSK medicine (p<0.05). Additionally, respondents' attitudes toward exposure and support from the interest group were significantly higher than those provided by the institution (p<0.05). Members believed OSSMIG increased interest in MSK medicine, improved confidence in their ability to perform orthopedics-related physical exams, strengthened mentorship with residents and attendings, and developed a connection with the Department of Orthopedic Surgery and its residents (median "Strongly Agree", interquartile range one and two scale items).

CONCLUSION

Since its inception 8 years ago, OSSMIG has been well received and has positively impacted University of Washington School of Medicine students through various interventions. Surgical interest groups should target both the students interested in primary care and surgery. Medical schools can provide additional exposure to MSK medicine by leveraging interest groups that provide early clinical experiences and supplementary instruction.

Injection of Unicameral Bone Cysts with Bone Marrow Aspirate and Demineralized Bone Matrix Avoids Open Curettage and Bone Grafting in a Retrospective Cohort

BACKGROUND

Many treatment options exist for unicameral bone cysts (UBC), without clear evidence of superiority. Meta-analyses have been limited by small numbers of patients in specific anatomic and treatment subgroups. The purpose of this study was to report the outcomes of injecting bone marrow aspirate and demineralized bone matrix (BMA/DBM) for the treatment of proximal humerus UBC.

METHODS

Fifty-one patients with proximal humerus lesions treated by BMA/DBM injection were retrospectively reviewed from a single academic medical center.

RESULTS

The mean number of injections performed per patient was 2.14 (range 1-5). Eleven patients underwent only one injection (22%), an additional 19 patients completed treatment after two injections (37%), four patients healed after three injections (8%), and one patient healed after four injections (2%). The cumulative success rate of serial BMA/DBM injections was 22% (11/51), 58% (30/51), 67% (34/51), and 69% (35/51). Eleven patients (22%) ultimately underwent open curettage and bone grafting, and five patients (10%) were treated with injection of calcium phosphate bone substitute.

CONCLUSION

A BMA/DBM injection strategy avoided an open procedure in 78% of patients with a proximal humerus UBC. The majority of patients underwent at least 2 injection treatments.

LEVEL OF EVIDENCE

Level IV retrospective cohort study.

Accuracy and Precision of a Surgical Navigation System: Effect of Camera and Patient Tracker Position and Number of Active Markers

Introduction:

Surgical navigation systems are increasingly used to aid resection and reconstruction of osseous malignancies. In the process of implementing image-based surgical navigation systems, there are numerous opportunities for error that may impact surgical outcome. This study aimed to examine modifiable sources of error in an idealized scenario, when using a bidirectional infrared surgical navigation system.

Materials and Methods:

Accuracy and precision were assessed using a computerized-numerical-controlled (CNC) machined grid with known distances between indentations while varying: 1) the distance from the grid to the navigation camera (range 150 to 247cm), 2) the distance from the grid to the patient tracker device (range 20 to 40cm), and 3) whether the minimum or maximum number of bidirectional infrared markers were actively functioning. For each scenario, distances between grid points were measured at 10-mm increments between 10 and 120mm, with twelve measurements made at each distance. The accuracy outcome was the root mean square (RMS) error between the navigation system distance and the actual grid distance. To assess precision, four indentations were recorded six times for each scenario while also varying the angle of the navigation system pointer. The outcome for precision testing was the standard deviation of the distance between each measured point to the mean three-dimensional coordinate of the six points for each cluster.

Results:

Univariate and multiple linear regression revealed that as the distance from the navigation camera to the grid increased, the RMS error increased (p<0.001). The RMS error also increased when not all infrared markers were actively tracking (p=0.03), and as the measured distance increased (p<0.001). In a multivariate model, these factors accounted for 58% of the overall variance in the RMS error. Standard deviations in repeated measures also increased when not all infrared markers were active (p<0.001), and as the distance between navigation camera and physical space increased (p=0.005). Location of the patient tracker did not affect accuracy (0.36) or precision (p=0.97)

Conclusion:

In our model laboratory test environment, the infrared bidirectional navigation system was more accurate and precise when the distance from the navigation camera to the physical (working) space was minimized and all bidirectional markers were active. These findings may require alterations in operating room setup and software changes to improve the performance of this system.

Reflections in a time of transition: orthopaedic faculty and resident understanding of accreditation schemes and opinions on surgical skills feedback

INTRODUCTION

Orthopaedic surgery is one of the first seven specialties that began collecting Milestone data as part of the Accreditation Council for Graduate Medical Education's Next Accreditation System (NAS) rollout. This transition from process-based advancement to outcome-based education is an opportunity to assess resident and faculty understanding of changing paradigms, and opinions about technical skill evaluation.

METHODS

In a large academic orthopaedic surgery residency program, residents and faculty were anonymously surveyed. A total of 31/32 (97%) residents and 29/53 (55%) faculty responded to Likert scale assessments and provided open-ended responses. An internal end-of-rotation audit was conducted to assess timeliness of evaluations. A mixed-method analysis was utilized, with nonparametric statistical testing and a constant-comparative qualitative method.

RESULTS

There was greater familiarity with the six core competencies than with Milestones or the NAS (p<0.05). A majority of faculty and residents felt that end-of-rotation evaluations were not adequate for surgical skills feedback. Fifty-eight per cent of residents reported that end-of-rotation evaluations were rarely or never filled out in a timely fashion. An internal audit demonstrated that more than 30% of evaluations were completed over a month after rotation end. Qualitative analysis included themes of resident desire for more face-to-face feedback on technical skills after operative cases, and several barriers to more frequent feedback.

DISCUSSION

The NAS and outcome-based education have arrived. Residents and faculty need to be educated on this changing paradigm. This transition period is also a window of opportunity to address methods of evaluation and feedback. In our orthopaedic residency, trainees were significantly less satisfied than faculty with the amount of technical and surgical skills feedback being provided to trainees. The quantitative and qualitative analyses converge on one theme: a desire for frequent, explicit, timely feedback after operative cases. To overcome the time-limited clinical environment, feedback tools need to be easily integrated and efficient. Creative solutions may be needed to truly achieve outcome-based graduate medical education.

Quality of life measures in soft tissue sarcoma

The assessment of health-related quality of life (HRQL) via patient-reported outcomes has the potential to answer critical questions and improve the care of soft tissue sarcoma (STS). This review outlines the rationale for quality of life measures in sarcoma, and details various instrument types: disease- and anatomic-specific, provider-generated, generic HRQL and health state utilities. Prior usage in STS populations, relative advantages of specific patient-reported outcome measures and a framework for selecting appropriate measures are discussed. Uniform incorporation of validated HRQL measures in STS clinical research would further the understanding of patient wellbeing beyond traditional clinical measures, and more widespread use of health state utilities measures in particular has the potential to facilitate comparative effectiveness research.

Lumbar stiffness as a collateral outcome of spinal arthrodesis: a preliminary clinical study

BACKGROUND CONTEXT

Although spinal arthrodesis can improve function by correcting deformity and reducing pain, it also by intention reduces spinal mobility. Increased spinal stiffness may have the potential to impair function and ability to perform activities of daily living (ADLs), independent of pain levels.

PURPOSE

To evaluate the ability to discriminate spinal stiffness from pain in ADLs after lumbar spine arthrodesis using two outcome instruments.

STUDY DESIGN

Cross-sectional study.

PATIENT SAMPLE

Consecutive cohort of lumbar spine fusion patients from a single surgeon's practice.

OUTCOME MEASURES

Oswestry Disability Index (ODI), Lumbar Stiffness Disability Index (LSDI), radiographs.

METHODS

We developed the LSDI questionnaire to assess the impact of spinal stiffness on ability to perform different ADLs. The LSDI and ODI were administered to 93 patients who underwent lumbar arthrodesis extending from one to five or more motion segments at a minimum follow-up of 1 year. Comparisons of mean LSDI and ODI scores between patients were made using generalized linear regression. A Pearson correlation coefficient (r) was computed to determine the relationship between the LSDI and ODI scores.

RESULTS

The sample included 61 women and 32 men, with mean age at surgery of 55.0 years (standard deviation [SD], 13.1) and mean time since surgery of 3.4 years (SD, 1.8). The mean LSDI score was 29.6 (SD, 19.2), and the mean ODI score was 39.7 (SD, 19.1). Comparing one-level and five-level arthrodesis, the LSDI scores were significantly different (p=.05), whereas the ODI scores were not significantly different (p=.36). Comparisons between other levels of arthrodesis did not show significant differences for either the LSDI or the ODI. Within the entire study group, LSDI and ODI scores were positively correlated (r=0.69, p<.001).

CONCLUSIONS

Difficulty in performing certain ADLs increases for patients with multilevel lumbar fusions as opposed to one-level arthrodesis. The LSDI distinguishes functional difficulties with ADLs accruing because of spinal stiffness, which appear to be independent of the functional limitations resulting from low back pain as measured by ODI.

Lumbar Stiffness Disability Index: pilot testing of consistency, reliability, and validity

BACKGROUND CONTEXT

The primary goal of surgical arthrodesis is to eliminate the motion of spinal segments in an effort to alleviate pain, improve deformity, and reduce disability. However, decreased spinal mobility may impair performance of activities of daily living (ADLs) due to the resulting stiffness or the lack of mobility of the fused segment. Current clinical outcome instruments do not seek information regarding the impact of spinal stiffness on functional ability. Therefore, a patient-reported outcome questionnaire measuring the impact of lumbar stiffness on functional abilities was devised and assessed for internal consistency, retest repeatability, and external validity.

PURPOSE

To develop and validate an outcome instrument to measure the collateral effect of stiffness after lumbar fusion on functional ability.

STUDY DESIGN

Cross-sectional pilot study.

PATIENT SAMPLE

Consecutive cohort of lumbar spine fusion patients from a single surgeon's practice.

OUTCOME MEASURES

Lumbar Stiffness Disability Index (LSDI) and Cobb angle measurements from digital radiographs.

METHODS

We developed and evaluated a 10-item questionnaire, referred to as the LSDI, which seeks information on the impact of spinal stiffness on ADLs after lumbar spinal arthrodesis. The questionnaire yields a score from 0 to 100, with higher scores indicating greater difficulty resulting from lumbar spinal stiffness in performing 10 different ADLs. The study sample comprised 32 lumbar arthrodesis patients at a minimum of 1 year postoperatively. All patients completed the questionnaire twice via telephone interviews conducted 4 weeks apart. Internal consistency was assessed using the Cronbach alpha, and retest reliability was measured using an intraclass correlation coefficient (ICC). External validity of the questionnaire was evaluated by correlating the scores with lumbar range of motion (LROM) as measured from the angular change between the inferior end plate of T12 and the superior end plate of S1 on standardized digital flexion and extension lateral radiographs.

RESULTS

The study sample included 22 women (69%) and 10 men (31%) with an average age of 63 years. The questionnaire demonstrated high internal consistency (Cronbach alpha=0.89). Retest reliability was also high (ICC=0.87). External validity was demonstrated by a statistically significant inverse relationship between LROM and LSDI scores (r=-0.71; p<.001).

CONCLUSIONS

This pilot study demonstrates that the LSDI questionnaire is a reliable and valid instrument for assessing functional limitations due to lumbar stiffness among spinal arthrodesis patients. The questionnaire is proposed for use in prospective evaluation of lumbar stiffness impacts after arthrodesis.

Effect of insurance status on the rate of surgery following a meniscal tear

BACKGROUND

Uninsured and underinsured Americans face barriers to access to medical care. The objective of this study was to characterize the effect of insurance status on whether patients with a torn meniscus proceed to elective arthroscopic knee surgery.

METHODS

The records from January 2003 through April 2006 at a single academic orthopaedic surgery institution in Massachusetts were retrospectively reviewed to identify patients diagnosed with a meniscal tear and to determine whether surgery had been performed within six months after the diagnosis. Six categories of insurance were identified: private insurance, Workers' Compensation, Medicare, Medicaid, Uncompensated Care Pool, and self pay. A comparison of the proportions of insured and uninsured patients who underwent surgery was the primary outcome measure.

RESULTS

A total of 1127 patients were identified, and 446 (40%) of them underwent surgery within six months after an office visit. The patients with and without surgery had similar age and sex distributions. When patients were divided, according to their insurance status, into insured and uninsured groups, no significant difference was found in the rate of surgery (p = 0.23). However, subgroup analysis revealed significant differences among the six insurance categories. Logistic regression analysis showed that patients in the self-pay group had a lower rate of surgery than those with private insurance (odds ratio, 0.33; 95% confidence interval, 0.14 to 0.75; p = 0.008), whereas patients receiving Workers' Compensation (odds ratio, 1.93; 95% confidence interval, 1.05 to 3.55; p = 0.034) and those receiving Medicaid (odds ratio, 1.63; 95% confidence interval, 1.09 to 2.42; p = 0.016) had higher surgical rates than those with private insurance.

CONCLUSIONS

The rate of elective arthroscopic knee surgery for meniscal tears varied significantly for some insurance categories at this single academic institution in Massachusetts. Further work is necessary to clarify the patient and surgeon factors influencing these disparities in clinical decision-making.

'To prove this is the industry's best hope': big tobacco's support of research on the genetics of nicotine addiction

BACKGROUND

New molecular techniques focus a genetic lens upon nicotine addiction. Given the medical and economic costs associated with smoking, innovative approaches to smoking cessation and prevention must be pursued; but can sound research be manipulated by the tobacco industry?

METHODOLOGY

The chronological narrative of this paper was created using iterative reviews of primary sources (the Legacy Tobacco Documents), supplemented with secondary literature to provide a broader context. The empirical data inform an ethics and policy analysis of tobacco industry-funded research.

FINDINGS

The search for a genetic basis for smoking is consistent with industry's decades-long plan to deflect responsibility away from the tobacco companies and onto individuals' genetic constitutions. Internal documents reveal long-standing support for genetic research as a strategy to relieve the tobacco industry of its legal responsibility for tobacco-related disease.

CONCLUSIONS

Industry may turn the findings of genetics to its own ends, changing strategy from creating a 'safe' cigarette to defining a 'safe' smoker.