Inter- and intra-observer variability associated with the use of the Mirels' scoring system for metastatic bone lesions

Musculoskeletal Metastasis From Soft-tissue Sarcomas: A Review of the Literature

Soft-tissue sarcomas are a rare and extremely heterogeneous group of cancers, representing <1% of all human malignancies. The lungs are the most common site of distant metastasis, followed by the bone, lymph nodes, liver, brain, and subcutaneous tissue. Clinical experience suggests that skeletal metastasis is part of the natural history affecting the prognosis and quality of life in these patients. Approximately 2.2% of patients have skeletal metastasis at diagnosis. However, up to 10% will develop skeletal metastasis after a mean interval of 21.3 months. Although systemic therapy with conventional chemotherapy remains the primary treatment modality for those with metastatic sarcoma, increased survival has been achieved in selected patients who receive multimodality therapy, including surgery, for their metastatic disease. The 5-year overall survival of patients with isolated bone metastases was 41.2% (26.9% to 54.9%), which decreased to 32.9% (21.2% to 45.1%) in the setting of combined bone and lung metastases. Moreover, the resection of the primary soft-tissue sarcoma is a predictor of survival, resulting in a 58% decrease in mortality after surgery (hazard ratio, 0.42, P = 0.013). Understanding the effect of these metastases on patient survival may influence imaging, surveillance, and treatment decisions.

Prophylactic surgical treatment using CT-based rigidity analysis vs. after the fact fracture treatment of pathologic femoral lesions

Background

Accurate comparison of prophylactic surgical treatment (PST) to after fracture treatment (AF) of patients with femoral metastatic disease requires more accurately identifying patients for impending fracture, such as with CT-based structural rigidity analysis (CTRA). This study compares a more accurately defined PST group (of impending fractures defined by CTRA) to AF for metastatic femoral disease.

Methods

PST patients were enrolled and treated by the PI in a longitudinal multicenter study of impending pathologic fractures evaluated for accuracy by CTRA. The AF patients were also treated by the senior author and were identified by retrospective chart review. Fifty-five patients were treated surgically for metastatic femoral lesions and were divided into three groups for the purpose of this study: Group I (AF), Group II (PST-high), and Group III (PST-low). Demographic information, comorbidities, and clinical variables of interest were collected by retrospective chart review; cost data was collected by collaboration with our hospital financial personnel (office of the Chief Financial Officer).

Results

Survival showed statistically significant differences favoring Group II. Transfusions in Group I were nearly twice those of Groups II and III, but there was no statistically significant (NS) difference between groups. Estimated blood loss (EBL) was generally with NS difference. Similarly, there were NS differences in LOS between groups. Discharge disposition showed statistically significant differences between groups (P=0.012, global). Discharge to home was highest in Group II (76%) and lowest in Group I (27%). Discharge to rehab was lowest in Group II (24%) and highest in Group I (47%). There were no discharges to hospice or morgue in Group II, while both occurred in Group I. Mean direct and total costs were highest in Group I ($18,837 and $31,997, respectively) and lowest in Group II ($16,094 and $27,357) but the differences were NS.

Conclusions

This study shows benefits of PST over AF in a group of PST patients more accurately defined to have impending pathologic fractures by CTRA definition.

Evaluation of Intramedullary Methods with Polymethylmethacrylate for Fixation of Bone Lesions of the Extremities

Objective  To evaluate the better potential and functional results in pain control in the treatment of pathological fractures and prophylactic fixation with an intramedullary nail associated with polymethylmethacrylate, compared with the utilization of an intramedullary nail in long bone tumor lesions.

Methods  From January 2012 to September 2017, 38 patients with 42 pathological lesions (fractures or impending fractures according to the Mirels criteria) were treated surgically. Sixteen patients allocated to the control group underwent a locked intramedullary nail fixation, and 22 patients with pathological lesions were allocated to treatment with an intramedullary nail associated with polymethylmethacrylate. Postoperatively, the patients were submitted to the Musculoskeletal Tumor Society (MSTS) rating scale, radiographic assessment, and to the assessment of events and complications related to the treatment.

Results  The evaluation using the MSTS questionnaire showed better functional results in the group associated with polymethylmethacrylate, in comparison with the control group, which obtained an average score of 16.375 out of a maximum of 30 points (54.6%). The group studied with association with polymethylmethacrylate obtained a mean of 22.36 points (74.5%). The procedure proved to be safe, with similar complication and severity rates, and with no statistical difference in comparison with the standard treatment.

Conclusion  Stabilization of tumor lesions with an internal fixation associated with the polymethylmethacrylate demonstrated early rehabilitation and improved the quality of life, allowing rapid functional recovery. The use of polymethylmethacrylate has advantages such as reduced bleeding, tumor necrosis and higher mechanical stability.

Fracture Risk of Long Bone Metastases: A Review of Current and New Decision-Making Tools for Prophylactic Surgery

Simple Summary

Long bone metastases are frequently a pivotal point in the oncological history of patients. Weakening of the bone results in pathologic fractures that not only compromise patient function but also their survival. Therefore, the main issue for tumor boards remains timely assessment of the risk of fracture, as this is a key consideration in providing preventive surgery while also avoiding overtreatment. As the Mirels scoring system takes into account both the radiological and the clinical criteria, it has been used worldwide since the 1990s. However, due to increasing concern regarding the lack of accuracy, new thresholds have been defined for the identification of impending fractures that require prophylactic surgery, on the basis of axial cortical involvement and biomechanical models involving quantitative computed tomography. The aim of this review is to establish a state-of-the-art of the risk assessment of long bone metastases fractures, from simple radiologic scores to more complex multidimensional bone models, in order to define new decision-making tools.

Abstract

Long bone pathological fractures very much reflect bone metastases morbidity in many types of cancer. Bearing in mind that they not only compromise patient function but also survival, identifying impending fractures before the actual event is one of the main concerns for tumor boards. Indeed, timely prophylactic surgery has been demonstrated to increase patient quality of life as well as survival. However, early surgery for long bone metastases remains controversial as the current fracture risk assessment tools lack accuracy. This review first focuses on the gold standard Mirels rating system. It then explores other unique imaging thresholds such as axial or circumferential cortical involvement and the merits of nuclear imaging tools. To overcome the lack of specificity, other fracture prediction strategies have focused on biomechanical models based on quantitative computed tomography (CT): computed tomography rigidity analysis (CT-RA) and finite element analysis (CT-FEA). Despite their higher specificities in impending fracture assessment, their limited availability, along with a need for standardization, have limited their use in everyday practice. Currently, the prediction of long bone pathologic fractures is a multifactorial process. In this regard, machine learning could potentially be of value by taking into account clinical survival prediction as well as clinical and improved CT-RA/FEA data.

Retrospective, multicenter, observational study of 112 surgically treated cases of humerus metastasis

INTRODUCTION

The humerus is the second most common site for metastasis in the peripheral skeleton. These humeral metastases (HM) occur in the midshaft in 42% to 61% of cases and theproximal humerus in 32% to 45% of cases. They are often secondary to primary breast (17-31%), kidney (13-15%) or lung (11-24%) cancer. The optimal surgical treatment between intramedullary (IM) procedures, fixation or arthroplasty is still being debated.

HYPOTHESIS

We hypothesized that fixation and/or arthroplasty are safe and effective options for controlling pain and improving the patients' function.

MATERIALS AND METHODS

Between 2004 and 2016, 11 French hospitals included 112 continuous cases of HM in 54 men (49%) and 57 women (51%). The average age was 63.7±13.4 years (30-94). The HM occurred in the context of primary breast (30%), lung (23%) or kidney (21%) cancers. The HM was proximal in 35% of cases, midshaft in 59% and distal in 7% of cases. Surgery was required in 69% of patients because of a pathological fracture. The surgical procedure consisted of bundle pinning, plate fixation, arthroplasty or locked IM nailing in 6%, 11%, 14% and 69% of patients, respectively.

RESULTS

Seven patients (6%) had to be reoperated due to surgical site complications including two infections and four fractures (periprosthetic or away from implant). Twelve patients (11%) experienced a general complication. The overall survival was 16.7 months, which was negatively and significantly impacted by the occurrence of a fracture, a diaphyseal location and the type of primary cancer. At the final assessment, 75% had normal or subnormal function and more than 90% were pain-free or had less pain. The final function was not related to the occurrence of a fracture or etiology of the metastasis. In epiphyseal and metaphyseal HM, there was a trend to better function after shoulder arthroplasty than after plate fixation or IM nailing.

CONCLUSIONS

Our initial hypothesis was confirmed. Our findings were consistent with those of other published studies. Based on our findings, we recommend using static locked IM nailing with cementoplasty for mid-shaft lesions and modular arthroplasty for destructive epiphyseal or metaphyso-epiphyseal lesions. The criteria for assessing humeral fracture risk should be updated to allow the introduction of a preventative procedure, which contributes to better survival.

LEVEL OF EVIDENCE

IV, retrospective study.

High rate of fracture in long-bone metastasis: Proposal for an improved Mirels predictive score

INTRODUCTION

Pathologic fracture is the most feared complication in long-bone metastasis. Various radiographic tools are available for identifying at-risk patients and guide preventive treatment. The Mirels score is the most frequently studied and widely used, but has been criticized, many patients not being operated on until the actual fracture stage. We therefore conducted a French national multicenter prospective study: (1) to determine the proportion of patients operated on at fracture stage versus preventively; (2) to compare Mirels score between the two; and (3) to identify factors for operation at fracture stage according to Mirels score and other epidemiological, clinical and biological criteria.

HYPOTHESIS

Simple discriminatory items can be identified to as to complete the Mirels score and enhance its predictive capacity.

MATERIAL AND METHODS

A non-controlled multicenter prospective study included 245 patients operated on for non-revelatory long-bone metastasis, comparing patients operated on for fracture versus preventively according to body-mass index (BMI), ASA score, Katagiri score items and the 4 Mirels items.

RESULTS

One hundred and twenty-six patients (51.4%) were operated on at fracture stage: 106 (84.1%) showed high risk on Mirels score (score>8), and 15 (11.9%) moderate risk (score=8). On multivariate analysis, 4 independent factors emerged: in increasing order, advanced age (OR=1.03; 95%CI 1.01-1.06), VAS pain score>6 (OR=1.47; 95%CI 1.02-2.11), WHO grade>2 (OR=2.74; 95%CI 1.22-6.15), and upper-limb location (OR=5.26; 95%CI 2.13-12.84).

DISCUSSION

The present study confirmed that more than half of patients with long-bone metastasis are operated on at actual fracture stage, in agreement with the literature. Several studies highlighted the weakness of the Mirels score as a predictive instrument. Comparison between preventive and fracture-stage surgery showed that upper-limb location, intense pain, advanced age and impaired functional status were associated with fracture-stage surgery, and should be taken into account alongside the original Mirels criteria. This improved scoring instrument remains to be validated in a prospective study.

LEVEL OF EVIDENCE

IV, prospective cohort study without control group.

Functional results and survival after surgery for peripheral skeletal metastasis: A 434-case multicenter retrospective series

INTRODUCTION

Peripheral skeletal metastasis (PSM) has a negative impact on quality of life. New treatments for the primary tumor or the osteolysis hold out hope of improved survival. The few published French series were small, and we therefore undertook a multicenter retrospective analysis of PSM surgery between 2005 and December 2016, with the aim of assessing: 1) rate and type of complications, 2) functional results, and 3) overall survival and corresponding risk factors.

HYPOTHESIS

The French data for clinical results, survival and complications are in agreement with the international literature.

MATERIALS AND METHOD

The series comprised 391 patients with 434 metastatic locations. There was female predominance: 247 women (63%). Two sites were treated in 46 patients (12%), and three in 5. The main etiologies were breast cancer (151/391: 39%), lung cancer (103/391: 26%) and kidney cancer (52/391: 13%). There was synchronous visceral metastasis in 166 patients (42.5%), other peripheral locations in 137 (35%) and spinal location in 142 (39%). One hundred (27%) had ASA score>3; 61 (16%) had WHO score>3. The reason for surgery was pathologic fracture (n=137: 35%). Locations were femoral (274: 70%), acetabular (58: 15%), humeral (40: 0%), tibial (12: 3%) or other (7: 2%).

RESULTS

There were surgery site complications in 41 patients (9.4%), including 13 surgery site infections, and general complications in 47 patients (11%), including 11 cases of thromboembolism, 6 of blood loss, 9 pulmonary complications and 6 perioperative deaths. Overall survival, taking all etiologies and sites together, was 10 months (range, 5 days to 9 years; 95% CI, 8-13 months), and significantly better in females (14 versus 6 months; p=0.01), under-65 year-olds (p=0.001), and in preventive surgery versus fractured PSM (p=0.001). Median survival was 22 months (95% CI, 17-28 months) after breast cancer, 3 months (95% CI, 2-5 months) after lung cancer, and 17 months (95% CI, 8-58 months) after kidney cancer. Preoperatively, walking was impossible for 143 patients (38%), versus 23 (6.5%) postoperatively; 229 patients (63.5%) could walk normally or nearly normally after surgery, versus 110 (28%) before. After surgery, 3 patients (6%) were not using their operated upper limb, versus 27 (45%) before; 30 patients (54%) had normal upper limb use after surgery, versus 8 (5%) before.

CONCLUSION

The study hypothesis was on the whole confirmed in terms of survival according to type of primary and whether surgery was indicated preventively or for fracture.

LEVEL OF EVIDENCE

IV, retrospective study without control group.

Mirels Scores in Patients Undergoing Prophylactic Stabilization for Femoral Metastatic Bone Disease in the Veterans Administration Healthcare System

INTRODUCTION

A retrospective review was performed for patients in the Veterans Administration Healthcare System who underwent prophylactic stabilization of the femur for metastatic disease. The goal was to evaluate indications for prophylactic stabilization through Mirels criteria.

METHODS

All veterans who underwent inpatient prophylactic femoral stabilization between October 2010 and September 2015 were identified. Procedure and demographic variables were collected by using chart review. Provider notes and radiographs were reviewed to calculate Mirels scores.

RESULTS

Ninety-two patients underwent confirmed prophylactic stabilization for metastatic bone disease. Lung cancer and multiple myeloma accounted for most lesions. The mean Mirels score was 10.3 (range 7 to 12). 3.2% of patients had a score of 7, and 6.5% had a score of 8. Most lesions were peritrochanteric (66%) and lytic (85%). There was more variability in size (mean 2.3), with 15% being under one third of bony width and 38% between one and two-thirds. The mean pain score was 2.5; 73% reported functional pain. Of lytic and peritrochanteric lesions (53% of all cases), 55% were less than two-thirds the cortical width and 31% lacked functional pain.

CONCLUSION

This retrospective study of prophylactically stabilized metastatic lesions revealed that more than 90% of patients had Mirels scores greater than 8, suggesting a substantial risk of pathologic fracture. Over half of all stabilized lesions were peritrochanteric and lytic. These criteria alone achieve a minimum Mirels score of 8; however, one-third of these lacked functional pain. Notably, Mirels' original paper found location and type criteria to be the least predictive of impending fracture. Contrariwise, functional pain was the most accurate predictor. Multiple studies have found poor specificity of the Mirels criteria. The high scores achievable by the location and type criteria may represent an overrepresentation of their contribution to fracture risk. Reconsideration of the relative weights of each criterion warrants further examination.

Early Clinical and Economic Outcomes of Prophylactic and Acute Pathologic Fracture Treatment

INTRODUCTION:

Pathologic fractures often contribute to adverse events in metastatic bone disease, and prophylactic fixation offers to mitigate their effects. This study aims to analyze patient selection, complications, and in-hospital costs that are associated with prophylactic fixation compared with traditional acute fixation after completed fracture.

MATERIALS AND METHODS:

The Nationwide Inpatient Sample database was queried from 2002 to 2014 for patients with major extremity pathologic fractures. Patients were divided by fixation technique (prophylactic or acute) and fracture location (upper or lower extremity). Patient demographics, comorbidities, complications, hospitalization length, and hospital charges were compared between cohorts. Preoperative variables were analyzed for potential confounding, and χ2 tests and Student’s t tests were used to compare fixation techniques.

RESULTS:

Cumulatively, 43,920 patients were identified, with 14,318 and 28,602 undergoing prophylactic and acute fixation, respectively. Lower extremity fractures occurred in 33,582 patients, and 10,333 patients had upper extremity fractures. A higher proportion of prophylactic fixation patients were white ( P = .043), male ( P = .046), age 74 years or younger ( P < .001), and privately insured ( P < .001), with decreased prevalence of obesity ( P = .003) and/or preoperative renal disease ( P = .008). Prophylactic fixation was also associated with decreased peri- and postoperative blood transfusions ( P < .001), anemia ( P < .001), acute renal failure ( P = .010), and in-hospital mortality ( P = .031). Finally, prophylactic fixation had decreased total charges (−$3,405; P = .001), hospitalization length ( P = .004), and extended length of stay (greater than 75th percentile; P = .012).

CONCLUSION:

Prophylactic fixation of impending pathologic fractures is associated with decreased complications, hospitalization length, and total charges, and should be considered in appropriate patients.

The validity of the Mirels score for predicting impending pathological fractures of the lower limb

Aims

The aim of this study was to validate the Mirels score in predicting pathological fractures in metastatic disease of the lower limb.

Patients and Methods

A total of 62 patients with confirmed metastatic disease met the inclusion criteria. Of the 62 patients, 32 were female and 30 were male. The mean age of patients was 65 years (35 to 89). The primary malignancy originated from the breast in 27 (44%) patients, prostate in 15 (24%) patients, kidney in seven (11%), and lung in four (6%) of patients. One patient (2%) had metastatic carcinoma from the lacrimal gland, two patients (3%) had multiple myeloma, one patient (2%) had lymphoma of bone, and five patients (8%) had metastatic carcinoma of unknown primary. Plain radiographs at the time of initial presentation were scored using Mirels system by the four authors. The radiographic components of the score (anatomical site, size, and radiographic appearance) were scored two weeks apart. Inter- and intraobserver reliability were calculated with Fleiss' kappa test. Bland-Altman plots were created to compare the variances of the individual components of the score and the total Mirels score.

Results

Kappa values for the interobserver variability of the components of the Mirels score were k = 0.554 (95% CI 0.483 to 0.626) for site, k = 0.342 (95% CI 0.285 to 0.400) for size, k = 0.443 (95% CI 0.387 to 0.499) for radiographic appearance, and k = 0.294 (95% CI 0.258 to 0.331)for the total score. Kappa values for the intra-observer reliability were k = 0.608 (95% CI 0.506 to 0.710) for site, k = 0.579 (95% CI 0.487 to 0.670) for size, k = 0.614 (95% CI 0.522 to 0.703) for radiographic appearance, and k = 0.323 (95% CI 0.266 to 0.379) for total score.

Conclusion

Our study showed fair to moderate agreement between authors when using the Mirels score, and moderate to substantial agreement when authors rescored radiographs. The Mirels score is subjective and lacks reproducibility in predicting the risk of pathological fracture. Cite this article: Bone Joint J 2018;100-B:1100-5.

Surgical strategy for benign lesions in proximal femur: internal fixation or endoprosthetic replacement

PURPOSE

The purpose of this study was to explore the indications for the two most frequently applied surgical procedures for benign lesions in the proximal femur.

METHODS

We retrospectively reviewed 142 patients with benign lesions in the proximal femur from January 2010 to January 2015. Internal fixation (IF) was adopted in 110 patients, while endoprosthetic replacement (EPR) was applied in 32 patients. Clinical data, including operation time, blood loss, hospitalization time, and hospitalization expenses, were compared between the groups. Limb mobilization was evaluated by the Musculoskeletal Tumor Society Score-93 (MSTS-93) and Harris Hip Score (HHS). Local recurrences and complications were statistically compared.

RESULTS

The average follow-up was 66 months (range 32-84 months). In the EPR group, operation time and hospitalization time were significantly shorter (p < 0.05 and p < 0.05, respectively), while blood loss and hospitalization expenses were significantly higher (p < 0.05 and p < 0.05, respectively). Functional outcomes of the MSTS-93 and HHS were higher at the three week follow-up in the EPR group (p < 0.001 and p < 0.001, respectively) but lower at 6 months (p = 0.031 and p = 0.042, respectively). No differences were observed in the two scores at three  months (p = 0.261 and p = 0.134, respectively). Local recurrence and complication rates were similar in the two groups (p = 0.895 and p = 0.942, respectively).

CONCLUSION

The strategy for benign proximal femur lesions should depend on the site, size, initial diagnosis, and thinning degree of cortical bone. IF and EPR both result in satisfactory local control and functional and radiological results, while EPR is more suitable for aggressive and recurrent lesions and serves as an effective measure after IF failure.

Updated Outcomes of Prophylactic Femoral Fixation

Despite an increasing number of patients with metastatic bone disease (MBD), minimal data exist regarding outcomes of patients undergoing prophylactic femoral fixation for MBD when compared with other frequently performed orthopedic operations, such as hemiarthroplasty of the femur. The authors performed a retrospective database review evaluating these procedures due to similar operative times and patient populations and also reviewed common comorbidities such as body mass index (BMI). The goal was to provide updated results of prophylactic femoral fixation and evaluate whether certain patient risk factors (eg, BMI) altered 30-day survival for patients with MBD. The authors reviewed 1849 patients with and without MBD treated by prophylactic fixation and hemiarthroplasty from 2006 to 2011 identified in the American College of Surgeons National Surgical Quality Improvement Program database. There were no significant differences in complications between patients undergoing surgical treatment for impending or actual femoral fracture. In addition, there were no differences between the 217 patients with MBD in either the hemiarthroplasty or prophylactic fixation groups because the rate of death within 30 days postoperatively was 5.56% and 3.30%, respectively (P=.526). When comparing BMI, obese patients had higher rates of wound infection, and underweight patients were more likely to develop pneumonia or die within 30 days postoperatively. Patients with impending femur fractures benefit from prophylactic fixation and perform as well in the short term as patients undergoing hemiarthroplasty. Certain BMI categories (underweight or obese) contributed to poorer outcomes. These findings provide updated information for discussing risks and benefits with surgical candidates.

The diagnostic imaging of bone metastases

BACKGROUND

Skeletal metastases are the most common malignant tumor in bone. Certain types of cancer (e.g., of the prostate or breast) are particularly likely to give rise to skeletal metastases, with prevalences of up to 70%. The diagnosis of skeletal metastases has a major impact on the overall treatment strategy and is an important determinant of the course of illness and the quality of life. The goal of diagnostic imaging is to detect skeletal metastases early, whenever they are suspected on the basis of clinical or laboratory findings or in patients who are at high risk. Other important issues include assessment of the risk of fracture and the response to treatment.

METHODS

This review is based on selected pertinent articles published up to December 2013.

RESULTS

Projectional radiography (plain films) is still useful for the immediate investigation of symptomatic bone pain and for the assessment of stability. Skeletal scintigraphy, the classic screening test for patients with cancer who do not have bone pain (specificity 81%, sensitivity 86%), has now been supplemented-in some cases, replaced-by other techniques. CT, including lowdose CT, is used to detect changes in bone structure due to metastases of some types of primary tumor (specificity 95%, sensitivity 73%); whole-body MRI, to detect metastases in the bone marrow and extraosseous soft tissues, e.g., metastases compressing the spinal cord (specificity 95%, sensitivity 91%); PET-CT, to detect metabolically active tumors (specificity 97%, sensitivity 90%).

CONCLUSION

Different imaging modalities are often used in combination to detect bone metastases optimally. Owing to advances in modern tomographic imaging, the current trend is toward whole-body imaging in a single session. The choice of method is based on the clinical situation and the type of primary tumor. Further research should address the impact of these costly and laborintensive imaging methods on treatment strategies and on the course of illness.

Does CT-based Rigidity Analysis Influence Clinical Decision-making in Simulations of Metastatic Bone Disease?

BACKGROUND

There is a need to improve the prediction of fracture risk for patients with metastatic bone disease. CT-based rigidity analysis (CTRA) is a sensitive and specific method, yet its influence on clinical decision-making has never been quantified.

QUESTIONS/PURPOSES

What is the influence of CTRA on providers' perceived risk of fracture? (2) What is the influence of CTRA on providers' treatment recommendations in simulated clinical scenarios of metastatic bone disease of the femur? (3) Does CTRA improve interobserver agreement regarding treatment recommendations?

METHODS

We conducted a survey among 80 academic physicians (orthopaedic oncologists, musculoskeletal radiologists, and radiation oncologists) using simulated vignettes of femoral lesions presented as three separate scenarios: (1) no CTRA input (baseline); (2) CTRA input suggesting increased risk of fracture (CTRA+); and (3) CTRA input suggesting decreased risk of fracture (CTRA-). Participants were asked to rate the patient's risk of fracture on a scale of 0% to 100% and to provide a treatment recommendation. Overall response rate was 62.5% (50 of 80).

RESULTS

When CTRA suggested an increased risk of fracture, physicians perceived the fracture risk to be slightly greater (37% ± 3% versus 42% ± 3%, p < 0.001; mean difference [95% confidence interval {CI}] = 5% [4.7%-5.2%]) and were more prone to recommend surgical stabilization (46% ± 9% versus 54% ± 9%, p < 0.001; mean difference [95% CI] = 9% [7.9-10.1]). When CTRA suggested a decreased risk of fracture, physicians perceived the risk to be slightly decreased (37% ± 25% versus 35% ± 25%, p = 0.04; mean difference [95% CI] = 2% [2.74%-2.26%]) and were less prone to recommend surgical stabilization (46% ± 9% versus 42% ± 9%, p < 0.03; mean difference [95% CI] = 4% [3.9-5.1]). The effect size of the influence of CTRA on physicians' perception of fracture risk and treatment planning varied with lesion severity and specialty of the responders. CTRA did not increase interobserver agreement regarding treatment recommendations when compared with the baseline scenario (κ = 0.41 versus κ = 0.43, respectively).

CONCLUSIONS

Based on this survey study, CTRA had a small influence on perceived fracture risk and treatment recommendations and did not increase interobserver agreement. Further work is required to properly introduce this technique to physicians involved in the care of patients with metastatic lesions. Given the number of preclinical and clinical studies outlining the efficacy of this technique, better education through presentations at seminars/webinars and symposia will be the first step. This should be followed by clinical trials to establish CTRA-based clinical guidelines based on evidence-based medicine. Increased exposure of clinicians to CTRA, including its underlying methodology to study bone structural characteristics, may establish CTRA as a uniform guideline to assess fracture risk.

LEVEL OF EVIDENCE

Level III, economic and decision analyses.

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

BACKGROUND

Controversy continues regarding the appropriate assessment of fracture risk in long bone lesions affected by disseminated malignancy.

QUESTIONS/PURPOSES

The purpose of this ongoing Musculoskeletal Tumor Society-sponsored, multi-institutional prospective cross-sectional clinical study is to compare CT-based structural rigidity analysis (CTRA) with physician-derived Mirels scoring for predicting pathologic fracture in femoral bone lesions. We hypothesized CTRA would be superior to Mirels in predicting fracture risk within the first year based on (1) sensitivity, specificity, positive predictive value, and negative predictive value; (2) receiver operator characteristic (ROC) analysis; and (3) fracture prediction after controlling for potential confounding variables such as age and lesion size.

METHODS

Consented patients with femoral metastatic lesions were assigned Mirels scores by the individual enrolling orthopaedic oncologist based on plain radiographs and then underwent CT scans of both femurs with a phantom of known density. The CTRA was then performed. Between 2004 and 2008, six study centers performed CTRA on 125 patients. The general indications for this test were femoral metastatic lesions potentially at risk of fracture. The enrolling physician was allowed the choice of prophylactic stabilization or nonsurgical treatment, and the local treating oncology team along with the patient made this decision. Of those 125 patients, 78 (62%) did not undergo prophylactic stabilization and had followup sufficient for inclusion, which was fracture through the lesion within 12 months of CTRA, death within 12 months of CTRA, or 12-month survival after CTRA without fracture, whereas 15 (12%) were lost to followup and could not be studied here. The mean patient age was 61 years (SD, 14 years). There were 46 women. Sixty-four of the lesions were located in the proximal femur, 13 were in the diaphysis, and four were distal. Osteolytic lesions prevailed (48 lesions) over mixed (31 lesions) and osteoblastic (15 lesions). The most common primary cancers were breast (25 lesions), lung (14 lesions), and myeloma (11 lesions). CTRA was compared with Mirels based on sensitivity/specificity analysis, ROC, and fracture prediction by multivariate analysis. For the CTRA, reduction greater than 35% in axial, bending, or torsional rigidities at the lesion was considered at risk for fracture, whereas a Mirels score of 9 or above, as suggested in the original manuscript, was used as the definition of impending fracture.

RESULTS

CTRA provided higher sensitivity (100% versus 66.7%), specificity (60.6% versus 47.9%), positive predictive value (17.6% versus 9.8%), and negative predictive value (100% versus 94.4%) compared with the classic Mirels definition of impending fracture (≥ 9), although there was considerable overlap in the confidence intervals. ROC curve analysis found CTRA to be better than the Mirels score regardless of what Mirels score cutoff was used. After controlling for potential confounding variables including age, lesion size, and Mirels scores, multivariable logistic regression indicated that CTRA was a better predictor of fracture (likelihood ratio test = 10.49, p < 0.001).

CONCLUSIONS

CT-based structural rigidity analysis is better than Mirels score in predicting femoral impending pathologic fracture. CTRA appears to provide a substantial advance in the accuracy of predicting pathological femur fracture over currently used clinical and radiographic criteria.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Treatment Planning and Fracture Prediction in Patients with Skeletal Metastasis with CT-Based Rigidity Analysis

PURPOSE

Pathologic fractures could be prevented if reliable methods of fracture risk assessment were available. A multicenter prospective study was conducted to identify significant predictors of physicians' treatment plan for skeletal metastasis based on clinical fracture risk assessments and the proposed CT-based Rigidity Analysis (CTRA).

EXPERIMENTAL DESIGN

Orthopedic oncologists selected a treatment plan for 124 patients with 149 metastatic lesions based on the Mirels method. Then, CTRA was performed, and the results were provided to the physicians, who were asked to reassess their treatment plan. The pre- and post-CTRA treatment plans were compared to identify cases in which the treatment plan was changed based on the CTRA report. Patients were followed for a 4-month period to establish the incidence of pathologic fractures.

RESULTS

Pain, lesion type, and lesion size were significant predictors of the pre-CTRA plan. After providing the CTRA results, physicians changed their plan for 36 patients. CTRA results, pain, and primary source of metastasis were significant predictors of the post-CTRA plan. Follow-up of patients who did not undergo fixation resulted in 7 fractures; CTRA predicted these fractures with 100% sensitivity and 90% specificity, whereas the Mirels method was 71% sensitive and 50% specific.

CONCLUSIONS

Lesion type and size and pain level influenced the physicians' plans for the management of metastatic lesions. Physicians' treatment plans and fracture risk predictions were significantly influenced by the availability of CTRA results. Due to its high sensitivity and specificity, CTRA could potentially be used as a screening method for pathologic fractures.

Assessment of image quality in soft tissue and bone visualization tasks for a dedicated extremity cone-beam CT system

OBJECTIVE

To assess visualization tasks using cone-beam CT (CBCT) compared to multi-detector CT (MDCT) for musculoskeletal extremity imaging.

METHODS

Ten cadaveric hands and ten knees were examined using a dedicated CBCT prototype and a clinical multi-detector CT using nominal protocols (80 kVp-108mAs for CBCT; 120 kVp- 300 mAs for MDCT). Soft tissue and bone visualization tasks were assessed by four radiologists using five-point satisfaction (for CBCT and MDCT individually) and five-point preference (side-by-side CBCT versus MDCT image quality comparison) rating tests. Ratings were analyzed using Kruskal-Wallis and Wilcoxon signed-rank tests, and observer agreement was assessed using the Kappa-statistic.

RESULTS

Knee CBCT images were rated "excellent" or "good" (median scores 5 and 4) for "bone" and "soft tissue" visualization tasks. Hand CBCT images were rated "excellent" or "adequate" (median scores 5 and 3) for "bone" and "soft tissue" visualization tasks. Preference tests rated CBCT equivalent or superior to MDCT for bone visualization and favoured the MDCT for soft tissue visualization tasks. Intraobserver agreement for CBCT satisfaction tests was fair to almost perfect (κ ~ 0.26-0.92), and interobserver agreement was fair to moderate (κ ~ 0.27-0.54).

CONCLUSION

CBCT provided excellent image quality for bone visualization and adequate image quality for soft tissue visualization tasks.

KEY POINTS

• CBCT provided adequate image quality for diagnostic tasks in extremity imaging. • CBCT images were "excellent" for "bone" and "good/adequate" for "soft tissue" visualization tasks. • CBCT image quality was equivalent/superior to MDCT for bone visualization tasks.

Bone health in breast cancer patients: a comprehensive statement by CECOG/SAKK Intergroup

Bone is the most common site of distant metastases in breast cancer that can cause severe and debilitating skeletal related events (SRE) including hypercalcemia of malignancy, pathologic fracture, spinal cord compression and the need for palliative radiation therapy or surgery to the bone. SRE are associated with substantial pain and morbidity leading to frequent hospitalization, impaired quality of life and poor prognosis. The past 25 years of research on the pathophysiology of bone metastases led to the development of highly effective treatment options to delay or prevent osseous metastases and SRE. Management of bone metastases has become an integral part of cancer treatment requiring expertise of multidisciplinary teams of medical and radiation oncologists, surgeons and radiologists in order to find an optimal treatment for each individual patient. A group of international breast cancer experts attended a Skeletal Care Academy Meeting in November 2012 in Istanbul and discussed current preventive measures and treatment options of SRE, which are summarized in this evidence-based consensus for qualified decision- making in clinical practice.

Benefits of early intramedullary nailing in femoral metastases

PURPOSE

Pathological fractures of the long bones are common complications of metastatic disease; however, the outcome of different surgical techniques for the treatment of these fractures has not been clearly defined. The aim of this study was to evaluate differences in prophylactic and therapeutic intramedullary nailing in femoral metastasic implants.

METHODS

Sixty-five patients with metastasis of the femur were analysed retrospectively (37 females; 28 males) between 1995 and 2011 (follow-up 15 months). Forty-four presented with pathological fractures and 21 impending fractures (Mirel ≥7). The operative treatments used were intramedullary fixation with reamed long Gamma nails. The studied parameters were survival, radiological and analytical findings, and functional outcomes.

RESULTS

Prophylactic nailing resulted in immediate postoperative deaths in 5% vs. 11.4% in therapeutic, and one technical complication was detected in each group. Among the surviving patients 75.9% of the fractures and 100 % of impending lesions were able to walk after the operation. The mean survival time was 11 months in the therapeutic (range 1-49) and 14 in the prophylactic group (1-34). The prophylactic intramedullary nails required a lower transfusion rate (1.4 concentrates vs. 3.0), mobilised earlier (day 4.0 vs. 9.7) and needed a shorter hospital stay (eight days vs. 16 days) compared to therapeutic nails (p < 0.05).

CONCLUSION

Femoral intramedullary nailing of metastasic lesions provides satisfactory results both clinically and radiologically. Early treatment of the metastases prevents fractures and gives better results, improving life quality of these patients.

Finite element analysis and computed tomography based structural rigidity analysis of rat tibia with simulated lytic defects

Finite element analysis (FEA), CT based structural rigidity analysis (CTRA) and mechanical testing is performed to assess the compressive failure load of rat tibia with simulated lytic defects. Twenty rat tibia were randomly assigned to four equal groups (n=5). Three of the groups included a simulated defect at various locations: anterior bone surface (Group 1), posterior bone surface (Group 2) and through bone defect (Group 3). The fourth group was a control group with no defect (Group 4). Microcomputed tomography was used to assess bone structural rigidity properties and to provide 3D model data for generation of the finite element models for each specimen. Compressive failure load calculated using CT derived rigidity parameters (FCTRA) was well correlated to failure load recorded in mechanical testing (R(2)=0.96). The relationships between mechanical testing failure load and the axial rigidity (R(2)=0.61), bending rigidity (R(2)=0.71) and FEA calculated failure loads, considering bone as an elastic isotropic (R(2)=0.75) and elastic transversely isotropic (R(2)=0.90) are also well correlated. CTRA stress, calculated adjacent to the defect, were also shown to be well correlated with yield stresses calculated using the minimum density at the weakest cross section (R(2)=0.72). No statistically significant relationship between apparent density and mechanical testing failure load was found (P=0.37). In summary, the results of this study indicate that CTRA analysis of bone strength correlates well with both FEA and results obtained from compression experiments. In addition there exist a good correlation between structural rigidity parameters and experimental failure loads. In contrast, there was no correlation between average bone density and failure load.

Biomechanical model of a high risk impending pathologic fracture of the femur: lesion creation based on clinically implemented scoring systems

BACKGROUND

Multiple classifications combine objective and subjective measures to predict fracture risk through a metastatic lesion. In our literature review, no studies have attempted to validate this predicted fracture risk from a biomechanical perspective. The study goal was to evaluate proximal femur strength after creating osteolytic defects. We report a standardized technique to re-create a metastatic lesion.

METHODS

Eight femoral matched pairs were procured and a standardized technique was used to create an osteolytic femoral neck defect in one femur with the contralateral specimen serving as the control. Femurs were loaded to failure in a material testing machine at 2 mm/s. Failure load (N) and location of failure were documented. 3D finite element (FE) femur models with and without the lesions were developed to predict von Mises stresses in the femoral neck and compare between the two models.

FINDINGS

Femurs containing the osteolytic defect failed at significantly lower loads than the intact specimens in a reproducible manner (intact: 10.69 kN (3.09 SD); lesion: 5.56 kN (2.03 SD), p<0.001). The average reduction in failure load was 48%, and the fracture pattern was consistent in all specimens. FE model comparison similarly predicted significantly higher von Mises stress at the lesion.

INTERPRETATION

Our methods and pathologic fracture model represent the clinical parameters of metastatic bone disease and suggest a significant reduction in structural integrity of the lesion-containing femur. Prophylactic surgical fixation may be warranted clinically to reduce the risk of pathologic fracture. Our model technique is reproducible and may be used in future studies.