Machine Learning-Assisted Decision Making in Orthopaedic Oncology.

¼ Artificial intelligence is an umbrella term for computational calculations that are designed to mimic human intelligence and problem-solving capabilities, although in the future, this may become an incomplete definition. Machine learning (ML) encompasses the development of algorithms or predictive models that generate outputs without explicit instructions, assisting in clinical predictions based on large data sets. Deep learning is a subset of ML that utilizes layers of networks that use various inter-relational connections to define and generalize data.¼ ML algorithms can enhance radiomics techniques for improved image evaluation and diagnosis. While ML shows promise with the advent of radiomics, there are still obstacles to overcome.¼ Several calculators leveraging ML algorithms have been developed to predict survival in primary sarcomas and metastatic bone disease utilizing patient-specific data. While these models often report exceptionally accurate performance, it is crucial to evaluate their robustness using standardized guidelines.¼ While increased computing power suggests continuous improvement of ML algorithms, these advancements must be balanced against challenges such as diversifying data, addressing ethical concerns, and enhancing model interpretability.

Cemented and Press-fit Femoral Stems for the Management of Oncologic Femoral Tumors.

BACKGROUND: Stem fixation in reconstruction after resection of femoral tumors is debated. Cemented stems offer immediate stability but risk aseptic loosening, while press-fit stems allow bone ingrowth but risk stress shielding and subsidence. Our retrospective review aimed to determine implant failure rates and their associated factors, as well as the rates of infection, debridement, and mortality for both fixation groups (cemented or press-fit stems) used in patients undergoing resection of femoral tumor disease and subsequent arthroplasty. METHODS: We retrospectively studied 252 patients who underwent resection of femoral tumors and subsequent arthroplasty using cemented (n = 173; 69%) or press-fit (noncemented) (n = 79; 31%) stems between 1999 and 2020. Implant failure was the primary outcome, with secondary outcomes including rates of implant infection, debridement, and mortality. Multivariable regression was done to assess risk factors for implant failures. RESULTS: The study found implant failure rates of 11% and 18% for cemented stems and press-fit stems, respectively. Lower stem to diaphyseal ratios ( P = 0.024) and younger patients ( P = 0.008) were associated with a higher risk of implant failure in cemented stems. The infection rates were 14% and 10% for cemented and press-fit stems, respectively. Debridement rates were 16% and 13% for cemented and press-fit stems, respectively, while the 1-year mortality rate was 16% for cemented stems and 1.5% for press-fit stems. CONCLUSIONS: This study is the largest of its kind, providing patient characteristics and outcomes in both cemented and press-fit stems in the setting of reconstruction for femoral tumors. Both methods can be effective, with outcomes dependent on patient-specific factors, such as life expectancy, activity level, and body habitus, as well as proper implant fit. Additional studies of both implants and longer follow-up are required to elucidate the optimal fixation method for each individual patient. LEVEL OF EVIDENCE: Level III, retrospective noncomparative study.

Myositis ossificans mimicking bone surface osteosarcoma: case report with literature review.

Myositis ossificans, a benign tumor composed of spindle cells and osteoblasts, can clinically and radiologically mimic osteosarcoma. While recognition and accurate diagnosis of myositis ossificans can be a challenge, this is critical as it may allow a conservative surgical approach to maximize functional outcomes. Herein, we present a patient with surface myositis ossificans confirmed genetically by the presence of COL1A1::USP6 gene fusion, along with a literature review. Due to the enhanced visualization of the bone matrix, computed tomography (CT) imaging may be a superior imaging modality to magnetic resonance (MR) imaging. Staged biopsies with samples obtained from the periphery and center of the lesions may allow pathologists to discern the zonal distribution histologically. Furthermore, immunohistochemistry fluorescence in situ hybridization and molecular testing can aid in the distinction of myositis ossificans from mimics. Because of their resemblance to other bone tumors, these cases of myositis ossificans highlight the importance of a multidisciplinary approach integrating clinical, radiologic, and pathologic analysis and involving serial imaging, sampling, and judicious use of ancillary immunohistochemical and molecular testing.

Bone Density Screening Rates Among Medicare Beneficiaries: An Analysis with a focus on Asian Americans.

PURPOSE: To report osteoporosis screening utilization rates among Asian American (AsA) populations in the USA. METHODS: We retrospectively assessed the use of dual-energy X-ray absorptiometry (DXA) screening using the Medicare 5% Research Identifiable Files. Using Current Procedural Terminology (CPT) codes indicative of a DXA scan, we identified patients recommended for DXA screening according to the ACR-SPR-SSR Practice Parameters (females ≥ 65 years, males ≥ 70 years). Sociodemographic factors and their association with screening were evaluated using chi-square tests. RESULTS: There were 80,439 eligible AsA beneficiaries, and 12,102 (15.1%) received osteoporosis screening. DXA rate for women was approximately four times greater than the rate for men (19.8% vs. 5.0%; p < 0.001). AsA beneficiaries in zip codes with higher mean household income (MHI) were more likely to have DXA than those in lower MHI areas (17.6% vs. 14.3%, p < 0.001). AsA beneficiaries aged < 80 were more likely to receive DXA (15.5%) than those aged ≥ 80 (14.1%, p < 0.001). There were 2,979,801 eligible non-AsA beneficiaries, and 496,957 (16.7%) received osteoporosis screening during the study period. Non-Hispanic white beneficiaries had the highest overall screening rate (17.5%), followed by North American Native (13.0%), Black (11.8%), and Hispanic (11.1%) beneficiaries. Comparing AsA to non-AsA populations, there were significantly lower DXA rates among AsA beneficiaries when controlling for years of Medicare eligibility, patient age, sex, location, and mean income (p < 0.001). CONCLUSION: We found lower than expected DXA screening rates for AsA patients. A better understanding of the barriers and facilitators to AsA osteoporosis screening is needed to improve patient care.

Can gas and infection coexist in the intervertebral disc? A retrospective analysis of percutaneously biopsied suspected discitis-osteomyelitis cases.

OBJECTIVES: To retrospectively evaluate the correlation between intradiscal gas and infection in patients percutaneously biopsied for suspected discitis-osteomyelitis. MATERIALS AND METHODS: We retrospectively reviewed all CT-guided discitis-osteomyelitis biopsies performed between 2002 and 2022. Two independent trained musculoskeletal radiologists evaluated for presence of gas on CT and/or MRI within 1 week of the biopsy. Disagreements were resolved by a third musculoskeletal radiologist. CT was considered the gold standard for the detection of intradiscal gas. Pathology, microbiology, and imaging and clinical follow-up were used as the gold standard for presence of infection. Interrater agreement on CT and MRI, sensitivity, and positive predictive value were calculated, using the presence of gas as an indicator (test positive) for "no infection." RESULTS: There were 284 biopsies in 275 subjects (mean age 58 ± 1.0 (range 4-99) years; 101 (37%) females and 174 (63%) males). Of the biopsies, 12 (4%) were cervical, 80 (28%) were thoracic, 192 (68%) were lumbar, and 200 (70%) were considered true discitis-osteomyelitis based on pathology, imaging, and clinical follow-up. Interrater agreement was excellent for CT (kappa = 0.83) and poor for MRI (kappa = - 0.021). The presence of gas had a 94% specificity and 76% negative predictive value for the absence of infection. CONCLUSION: CT is the preferred method for detecting intradiscal gas. The presence of gas means that discitis-osteomyelitis is unlikely. If intradiscal gas is present in the setting of discitis-osteomyelitis, the gas bubbles tend to be smaller and fewer in number.

Biomarkers of Body Composition.

The importance and impact of imaging biomarkers has been increasing over the past few decades. We review the relevant clinical and imaging terminology needed to understand the clinical and research applications of body composition. Imaging biomarkers of bone, muscle, and fat tissues obtained with dual-energy X-ray absorptiometry, computed tomography, magnetic resonance imaging, and ultrasonography are described.

Phosphaturic mesenchymal tumor: management and outcomes of ten patients treated at a single institution.

BACKGROUND: Phosphaturic mesenchymal tumor (PMT) is a rare tumor that causes tumor-induced osteomalacia. Patients present with non-specific symptoms secondary to renal phosphate wasting and decreased bone mineralization. We sought to assess: (1) What are the common presenting features, laboratory and imaging findings, histologic findings of phosphaturic mesenchymal tumors? (2) What are the available treatment strategies for phosphaturic mesenchymal tumors and their long-term outcomes in terms of local recurrence and symptom control after treatment? METHODS: We retrospectively identified patients with a histologic diagnosis of PMT located in the axial or appendicular skeleton, or surrounding soft tissues. A total of 10 patients were finally included in our study. RESULTS: Median tumor size was 1.9 cm (range, 1.1 to 6.1) and median time from symptom onset to diagnosis was 3 years (range, 0.5 to 15 years). All patients but one presented with hypophosphatemia (median 1.9 mg/dL, range 1.2 to 3.2). Pre-operative FGF-23 was elevated in all cases (median 423.5 RU/mL, range 235 to 8950). Six patients underwent surgical resection, three were treated percutaneously (radiofrequency ablation or cryoablation), and one refused treatment. Only one patient developed local recurrence and no patients developed metastatic disease. At last follow-up, nine patients showed no evidence of disease and one was alive with disease. CONCLUSION: Phosphaturic mesenchymal tumor is a rare tumor presenting with non-specific symptoms. Surgery is the standard treatment when negative margins can be achieved without significant morbidity. In patients with small tumors in surgically-inaccessible areas, radiofrequency ablation or cryoablation can be performed successfully.

Bone Marrow Biopsies: Is CT, Fluoroscopy, or no Imaging Guidance the Most Cost-Effective Strategy?

RATIONALE AND OBJECTIVES: To determine the most cost-effective strategy for pelvic bone marrow biopsies. MATERIALS AND METHODS: A decision analytic model from the health care system perspective for patients with high clinical concern for multiple myeloma (MM) was used to evaluate the incremental cost-effectiveness of three bone marrow core biopsy techniques: computed tomography (CT) guided, and fluoroscopy guided, no-imaging (landmark-based). Model input data on utilities, costs, and probabilities were obtained from comprehensive literature review and expert opinion. Costs were estimated in 2023 U.S. dollars. Primary effectiveness outcome was quality adjusted life years (QALY). Willingness to pay threshold was $100,000 per QALY gained. RESULTS: No-imaging based biopsy was the most cost-effective strategy as it had the highest net monetary benefit ($4218) and lowest overall cost ($92.17). Fluoroscopy guided was excluded secondary to extended dominance. CT guided biopsies were less preferred as it had an incremental cost-effectiveness ratio ($334,043) greater than the willingness to pay threshold. Probabilistic sensitivity analysis found non-imaging based biopsy to be the most cost-effective in 100% of simulations and at all willingness to pay thresholds up to $200,000. CONCLUSION: No-imaging based biopsy appears to be the most cost-effective strategy for bone marrow core biopsy in patients suspected of MM. CLINICAL RELEVANCE: No imaging guidance is the preferred strategy, although image-guidance may be required for challenging anatomy. CT image interpretation may be helpful for planning biopsies. Establishing a non-imaging guided biopsy service with greater patient anxiety and pain support may be warranted.

CT-guided lumbar facet cyst rupture and corticosteroid injection: technique, approach, and procedural and clinical success rates.

PURPOSE: To evaluate success rates of computed tomography (CT)-guided lumbar facet synovial cyst (LFC) rupture. MATERIALS AND METHODS: We retrospectively reviewed all LFC ruptures performed by a single musculoskeletal radiologist with > 10 years of experience, using posterior facet approach and/or direct puncture by ipsilateral/contralateral interlaminar, or transforaminal approach. All patients also received a corticosteroid injection. Rupture rates were calculated, and clinical success rate was determined through medical record review. Pre-procedure magnetic resonance imaging (MRI) images and CT procedure images were also reviewed for LFC and facet joint imaging features that may predict rupture. RESULTS: There were 37 patients, 17 (46%) female and 20 (54%) male, ages 62 ± 12 (range 39-87) years. Thirty-four (92%) of LFC were successfully ruptured, 17 (50%) by facet approach and 17 (50%) by direct cyst puncture. At least one direct puncture approach was possible in 35 (95%) patients. No MRI or CT LFC or facet joint features predicted cyst rupture. Thirty-one (91%) of patients reported immediate pain relief, and 19 (53%) did not have further intervention for LFC-related pain. Sixteen (84%) of these patients remained pain-free for an average follow-up time period of 28 months. Fourteen (39%) of patients required surgical intervention. There were no complications. CONCLUSION: Our systematic approach to CT-guided LFC rupture is safe and has high technical and clinical success rates similar to prior studies. Since there are no definitive imaging features that determine rupture success, this procedure can almost always be attempted as a first-line treatment for LFC.

Current state of musculoskeletal fellowship program directors and future directions.

OBJECTIVE: To better understand the current state of musculoskeletal fellowship program directors and identify opportunities for formal training that could increase job satisfaction, provide a broader knowledge base for mentoring/advising trainees and increase diversity in musculoskeletal radiology. MATERIALS AND METHODS: Eighty-one fellowship program directors who signed the Fellowship Match Memorandum of Understanding with the Society of Skeletal Radiology were sent a survey with questions about demographics, career, background, and training both for musculoskeletal radiology and for the fellowship director role. RESULTS: A 57/81 (70%) of program directors responded, representing 27 different states with a range of 1-9 fellowship positions. Nearly half are in their forties (48%) with most identifying as White (67%) followed by Asian (30%). The majority are male (72%) with over half (60%) remaining at the institution where they completed prior training. Over half plan to change roles within 5 years and do not feel adequately compensated. Top qualities/skills identified as important for the role include effective communication, being approachable, and clinical excellence. Other than clinical excellence, most do not report formal training in skills identified as important for the role. CONCLUSIONS: Given the high amount of interaction with trainees, program directors play a key role in the future of our subspecialty. The low diversity among this group, the lack of formal training, and the fact that most do not feel adequately compensated could limit mentorship and recruitment. Program directors identified effective communication, organizational/planning skills, and conflict resolution as the top skills they would benefit from formal training.