Evaluation of Compressed SENSE on Image Quality and Reduction of MRI Acquisition Time: A Clinical Validation Study.

RATIONALE AND OBJECTIVES: To evaluate the effect of compressed SENSE (CS) in clinical settings on scan time reduction and image quality. MATERIALS AND METHODS: Ninety-five magnetic resonance imaging (MRI) scans from different anatomical regions were acquired, consisting of a standard protocol sequence (SS) and sequence accelerated with CS. Anonymized paired sequences were randomly displayed and rated by six blinded subspecialty radiologists. Side-by-side evaluation on perceived sharpness, perceived signal-to-noise-ratio (SNR), lesion conspicuity, and artifacts were compared and scored on a five-point Likert scale, and individual image quality was evaluated on a four-point Likert scale. RESULTS: CS reduced overall scan time by 32% while maintaining acceptable MRI quality for all regions. The largest time savings were seen in the spine (mean = 68 seconds, 44% reduction) followed by the brain (mean = 86 seconds, 37% reduction). The sequence with maximum time savings was intracranial 3D-time-of-flight magnetic resonance angiography (202 seconds, 56% reduction). CS was mildly inferior to SS on perceived sharpness, perceived SNR, and lesion conspicuity (mean scores = 2.32-2.96, P < .001 [1: SS superior; 3: equivalent; 5: CS superior]). CS was equivalent to SS for joint and body scans on overall image quality (CS = 3.02-3.37, SS = 3.04-3.68, P > .05, [1: lowest quality and 4: highest quality]). The overall image quality of CS was slightly less for brain and spine scans (mean CS = 2.79-3.05, mean SS = 3.13-3.43, P = .021) but still diagnostic. Good overall clinical acceptance for CS (88%) was noted with full clinical acceptance for body scans (100%) and high acceptance for other regions (68%-95%). CONCLUSION: CS significantly reduced MR acquisition time while maintaining acceptable image quality. The implementation of CS may improve departmental workflows and enhance patient care.

Incomplete Periprosthetic Atypical Femoral Fracture With Concomitant Hip and Knee Arthroplasties: A Case Report.

CASE: We present a case of an incomplete periprosthetic femoral fracture at the mid-distal third of the femoral stem after 11 months of bisphosphonate use. It is 1 of 4 cases of mid-distal periprosthetic atypical femoral fractures (PAFFs) found in our literature review. She was treated with protected weight-bearing, cessation of bisphosphonates, and teriparatide. Eighteen months after diagnosis, follow-up radiographs showed a bridging callus and reduction of a transverse fracture line. CONCLUSION: The incomplete PAFF was contributed by both decreased bone turnover from bisphosphonate use and increased mechanical stress at the lateral femoral cortex. Her previous left bipolar hemiarthroplasty and subsequent Total Knee Arthroplasty shifted the mechanical alignment medially, hence increasing tensile stress.

Factors affecting healing and progression of conservatively treated incomplete atypical femoral fractures: retrospective observational study.

INTRODUCTION: Incomplete atypical femoral fractures (iAFF) may occur with prolonged bisphosphonate usage. Factors influencing iAFF healing and progression are not well understood. This study of conservatively managed iAFF assessed factors influencing iAFF healing and progression including the effects of bisphosphonates and teriparatide use. MATERIALS AND METHODS: Single-center retrospective observational study of 69 consecutive patients with 78 radiographically confirmed iAFF from 2002 to 2017. Serial radiographs assessed for focal cortical thickening, dreaded black line (DBL) and complete fracture. Chief outcome measures were DBL healing and complete fracture. RESULTS: DBL had a significant association (p < 0.05) with fracture progression by multivariable logistic regression (55.8% versus 25.7%, odds ratio [OR] 26.57 (95% CI 1.40-504.78)) and shorter fracture-free survival (mean 3.21 versus 6.27 years). Presence of symptoms was associated with shorter fracture-free survival (mean 2.68 versus 5.98 years). Discontinuing bisphosphonates had significant associations (p < 0.001) by multivariable logistic regression with decreased fracture rate (11.6% versus 92.0%; OR 0.00, 95% CI 0.00-0.08) and longer fracture-free survival (mean 7.52 versus 1.99 years). DBL healing occurred in 36.4%, only when bisphosphonates were discontinued. Age, sex, race, fracture site, glucocorticoid use, teriparatide supplementation and duration of bisphosphonate use showed no statistically significant effect although teriparatide use appeared to improve DBL healing (50% versus 17.9%, p = 0.188). CONCLUSIONS: In conservatively managed iAFF, DBL healing occurred in 36.4% if bisphosphonates were discontinued. Bisphosphonates and DBL were significantly associated with fracture progression and together with symptoms with fracture survival.

Bilateral Atypical Femur Fractures After Denosumab in a Bisphosphonate Naive Patient: A Case Report.

A case report of bilateral atypical femur fractures (AFF) in a bisphosphonate naive patient. A 62-year-old female bisphosphonate naive patient was started on denosumab for osteoporosis. Approximately 3 years later she complained of right hip pain and was found to have a bilateral incomplete AFFs. She was asymptomatic on the left lower limb. Patient was managed conservatively and placed on protected weight bearing on both legs. Symptoms subsequently resolved over a period of 3 months, although radiographic findings remained at approximately 1 year. AFFs may be associated with patients on denosumab therapy even without a prior history of bisphosphonate use. Patients should be counselled appropriately and monitored for such complications.

Higher Charlson Comorbidity Index Increases 90-Day Readmission Rate with Poorer Functional Outcomes in Surgically Treated Hip Fracture Patients.

INTRODUCTION: The associated mortality and morbidity in hip fracture patients pose a major healthcare burden for ageing populations worldwide. We aim to analyse how an individual's comorbidity profile based on age-adjusted Charlson Comorbidity Index (CCI) may impact on functional outcomes and 90-day readmission rates after hip fracture surgery. MATERIALS AND METHODS: Surgically treated hip fracture patients between 2013 and 2016 were followed up for 1-year and assessed using Parker Mobility Score (PMS), EuroQol-5D (EQ-5D) and Physical and Mental Component Scores (PCS and MCS, respectively) of Short Form-36 (SF-36). Statistical analysis was done by categorising 444 patients into three groups based on their CCI: (1) CCI 0-3, (2) CCI 4-5 and (3) CCI ≥ 6. RESULTS: PMS, EQ-5D and SF-36 PCS were significantly different amongst the CCI groups pre-operatively and post-operatively at 3, 6 and 12 months (all P < 0.05), with CCI ≥ 6 predicting for poorer outcomes. In terms of 90-day readmission rates, patients who have been readmitted have poorer outcome scores. Multivariate analysis showed that high CCI scores and 90-day readmission rate both remained independent predictors of worse outcomes for SF-36 PCS, PMS and EQ-5D. DISCUSSION: CCI scores ≥6 predict for higher 90-day readmission rates, poorer quality of life and show poor potential for functional recovery 1-year post-operation in hip fracture patients. 90-day readmission rates are also independently associated with poorer functional outcomes. Peri-operatively, surgical teams should liaise with medical specialists to optimise patients' comorbidities and ensure their comorbidities remain well managed beyond hospital discharge to reduce readmission rates. With earlier identification of patient groups at risk of poorer functional outcomes, more planning can be directed towards appropriate management and subsequent rehabilitation. CONCLUSION: Further research should focus on development of a stratified, peri-operative multidisciplinary, hip-fracture care pathway treatment regime based on CCI scores to determine its effectiveness in improving functional outcomes.

Ultrasonic Percutaneous Tenotomy for Recalcitrant Lateral Elbow Tendinopathy: Clinical and Sonographic Results at 90 Months.

BACKGROUND: In a study from our institution, ultrasonic percutaneous tenotomy of the brevis and the common extensor tendon for recalcitrant lateral elbow tendinopathy showed excellent safety profiles, high tolerability, efficiency, sustained pain relief, functional improvement, and sonographic evidence of tissue healing in 20 patients at 3 years' follow-up. PURPOSE: To explore the long-term clinical and sonographic results of ultrasonic percutaneous tenotomy of the brevis and the common extensor tendon. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: The same cohort of 20 patients was recalled after 7 years, and visual analog scale (VAS) for pain and Disabilities of the Arm, Shoulder and Hand (DASH) scores, need for secondary intervention, and overall satisfaction were assessed. They were also reassessed using ultrasound imaging of the brevis and the common extensor tendon to evaluate tendon hypervascularity, tendon thickness, and the progress or the recurrence of the hypoechoic scar tissue. RESULTS: We successfully scored 19 patients and performed ultrasound on 16 patients with a median follow-up of 90 months (range, 86-102 months). There were no adverse outcomes and satisfaction remained at 100% (6 patients, satisfied; 13 patients, very satisfied). No patient developed a recurrence of symptoms and signs of lateral elbow tendinopathy, and therefore no secondary intervention was required. The improvement from baseline and early term scores was sustained (P < .001 for all). At 90 months, there was a significant improvement in VAS scores and DASH-Compulsory scores compared with preprocedure scores and all follow-up times until 3 months. There was no difference in VAS scores and DASH-Compulsory scores at 90 months compared with 6 and 36 months. For DASH-Work scores, there was a significant improvement at 90 months compared with preprocedure scores, but there was no difference between DASH-Work scores at 90 months and scores at all other points of follow-up. At 90 months, hypervascularity remained resolved in 79% of patients, while all patients had reduced tendon swelling and sustained resolution or reduction of the hypoechoic lesion. CONCLUSION: At the long-term follow-up of 90 months, ultrasonic percutaneous tenotomy of the brevis and the common extensor tendon, previously shown to enhance recovery of lateral elbow tendinopathy, demonstrated good durability of pain relief and functional recovery that was previously achieved. This was accompanied by sustained sonographic tissue healing with no significant deterioration.

Preoperative hypoalbuminemia: Poor functional outcomes and quality of life after hip fracture surgery.

AIMS: Hip fracture patients have severe deterioration of their quality of life and function after their injury. Markers of malnutrition such as low albumin and low body mass index (BMI) have been shown to increase mortality and complication rates but their effect on recovery of quality of life and function after hip fracture surgery is unclear. The main aim of this paper is to further investigate if low albumin affects recovery after hip fracture surgery, while additionally studying low BMI as a possible risk factor for poor recovery. PATIENTS AND METHODS: Retrospective analysis of 971 patients who underwent surgery for fragility hip fractures between January 2012 and December 2016 was performed. Demographic data, preoperative serum albumin and haemoglobin levels, BMI, Charlson Comorbidity Index (CCI), type of surgery (fixation vs replacement) and site of surgery were obtained. Patients were assessed using the Parker Mobility Scale (PMS), Harris Hip Score(HHS), Medical Outcomes Study 36-item Short-Form Health Survey (SF36) at pre-fracture, 6 weeks and 6 months after surgery. HHS was not available pre-operatively. Patients were grouped according to their albumin levels (low ≤35 g/L or normal) and BMI (underweight <18.5 or normal). Univariate and multivariate analyses were performed to examine the association between albumin and BMI and 6-month scores. RESULTS: On univariate analysis, patients with low albumin ≤35 g/L had lower baseline PMS and SF36 Physical Functioning (PF) score. On multivariate analysis, preoperative hypoalbuminemia was associated with lower 6-month HHS, PMS and SF36 PF scores even after accounting for baseline scores and other confounders. BMI had no effect on 6-month scores. CONCLUSION: Low albumin (≤35 g/L) is prevalent in elderly hip fracture patients and is associated with slower recovery of function and quality of life after surgery. Low albumin can be a useful prognostic tool to identify patients with poor recovery for further intervention or rehabilitation after hip fracture surgery.

Chest Radiographs and CTs in the Era of COVID-19: Indications, Operational Safety Considerations and Alternative Imaging Practices.

Coronavirus disease-19 (COVID-19) is a pathogen that has shown an ability for sustained community transmission. To ensure utmost safety, radiology services will need to adapt to this disease in the coming months and possibly years ahead. This will include learning how to perform radiographs and CT in a safe and sustainable manner. Due to the risk of nosocomial spread of disease, the judicious use and implementation of strict infection protocols is paramount to limit healthcare worker and patient transmission. Between 28 January 2020 and 8 June 2020, our institution performed 12,034 radiographs and 178 CT scans for suspected or confirmed COVID-19 patients. As of 8 June 2020, there have been no documented instances of healthcare staff acquiring COVID-19 during the course of work. In this article, we present the indications and operational considerations used by our institution to safely image patients with suspected or confirmed COVID-19. Alternative practices for imaging radiographs are also discussed.

Computed tomography-based diagnosis of occult fragility hip fractures offer shorter waiting times with no inadvertent missed diagnosis.

PURPOSE: Surgical delay due to the wait for advanced cross-sectional imaging in occult fragility hip fracture management is not well studied. Our study aims to investigate computed tomography (CT) as an alternative to the gold standard magnetic resonance imaging (MRI) in occult hip fracture workup to decrease surgical delay. METHODS: We conducted a retrospective review of all CTs and MRIs performed between 2015 and 2017 for patients with clinically suspected fragility hip fractures and negative plain radiographs to investigate surgical delay resulting from the wait for advanced imaging and representations due to missed fractures. RESULTS: A total of 243 scans (42 CTs and 201 MRIs) were performed for occult hip fracture workup over the study timeframe, of which 49 patients (20%) had occult hip fractures [CT: 6 (14%), MRI: 43 (21%), p = 0.296)]. There were no readmissions for fracture in the 12 months following a negative scan. The CT group had shorter waiting times (CT: 29 ± 24 h, MRI: 44 ± 32 h, p = 0.004) without significantly reducing surgical delay (CT: 82 ± 36 h, MRI: 128 ± 58 h, p = 0.196). The MRI group had a higher number of patients with a cancer history (p = 0.036), reflective of the practice for workup of possible metastases as a secondary intention. CONCLUSION: Advanced cross-sectional imaging wait times in occult hip fracture workup contribute significantly to surgical delay. Modern CT techniques are not inferior to MRI in detecting occult fractures and may be a suitable alternative in the absence of a cancer history if MRI cannot be obtained in a timely fashion or is contraindicated. Clinicians should utilize the more readily available imaging modality to reduce surgical delay.

Real-time sonoelastography evaluation of the Achilles tendon following ultrasound-guided platelet-rich plasma injection and eccentric exercise for the treatment of refractory Achilles tendinopathy.

The objective of this study was to investigate the feasibility of using sonoelastography to depict Achilles tendon stiffness after platelet-rich plasma injection and eccentric exercise for chronic Achilles tendinopathy, and to correlate sonoelastography findings with clinical outcome up to 12 months after treatment. Forty-five Achilles tendons from 45 patients (33 males, 12 females; mean age 51 years) were examined using sonoelastography and ultrasound at baseline, 4-6 weeks, 6 months and 12 months post-treatment. The strain ratio (between Achilles tendon and Kager's fat) during sonoelastography was obtained. The proportion of tendons with hypoechogenicity and neovascularity were documented. Clinical outcomes were assessed by the Victorian Institute of Sport Assessment-Achilles questionnaire and correlated with sonographic findings. The Victorian Institute of Sport Assessment-Achilles improved significantly from 38.4 (±14.1) at baseline, 77.2 (±12.5) at 6 months (p < 0.001) to 81.2 (±10.8) at 12 months (p < 0.001). The strain ratio values were 2.16 (±1.02) at baseline, 2.03 (±0.67) at 4-6 weeks, 1.81 (±0.62) at 6 months and 1.19 (±0.34) at 12 months with a significant reduction observed at 6 months (p = 0.006) and 12 months (p < 0.001). At 12-month evaluation, none of the tendons regained a normal echotexture. Strain ratio demonstrated a moderately good inverse correlation with Victorian Institute of Sport Assessment-Achilles (r = -0.610, p<0.001) while B-mode and Doppler ultrasound did not show a significant correlation (r = -0.041, p = 0.817, and r = -0.116, p = 0.514). Achilles tendon stiffness shows moderately good correlation with clinical symptom at 12-month post-treatment. Sonoelastography using strain ratio could be a promising ancillary tool for monitoring Achilles tendon healing after treatment.

Trigger finger at wrist caused by degenerative changes of the flexor tendon sheath and carpal tunnel syndrome: a case report.

Trigger finger at wrist is a rare condition. Symptoms include finger triggering, snapping or catching at the wrist level. Carpal tunnel syndrome and median nerve compression neuropathy are almost always associated. We reported one case which was caused by degenerative changes of the flexor tendon sheath and carpal tunnel syndrome.

Bone cross-sectional geometry is not associated with atypical femoral fractures in Asian female chronic bisphosphonate users.

INTRODUCTION: Atypical femoral fractures (AFF) tend to occur in Asian women with prolonged bisphosphonate exposure. Hip geometry is thought to contribute to the risk of AFF formation. We examined the hip structural geometry parameters in Asian female chronic bisphosphonate users who sustained an AFF and compared them to chronic bisphosphonate users who did not sustain any femoral fracture (NFF) and bisphosphonate-naïve patients who sustained an osteoporotic femoral fracture (OFF). MATERIALS & METHODS: Thirty-one patients with AFFs were gender and age-matched to 31 patients with NFFs and 49 patients with OFFs. The Hip Structural Analysis parameters analyzed were bone mineral density (BMD), cross-sectional area (CSA; a metric of resistance to axial compression), section modulus (SM; a metric of resistance to tensile loads), average cortical thickness (ACT; mean thickness of the femoral cortices), buckling ratio (BR; an index of likelihood of local buckling), and neck shaft angle (NSA; the angle between the neck and shaft axes). The regions analyzed were three cross-sections measured at the narrowest femoral neck diameter, the intertrochanteric area, and the proximal femoral shaft. One-way ANOVA with Bonferroni adjustment for multiple comparisons was used to compare parameters between the three patient groups, with statistical significance defined as p<0.05. RESULTS: There were no statistical differences in parameters between patients with AFFs and patients with NFFs at all measured regions. Patients with AFFs and NFFs had statistically higher BMD, CSA, ACT, SM values and lower BR values at the NN and IT regions than patients with OFFs. Additionally, patients with NFFs had statistically higher SM values at the IT region than patients with OFFs, while patients with AFFs had statistically higher BMD, CSA, and ACT values at the FS region. All other measured parameters were not statistically different between the groups. CONCLUSIONS: Chronic bisphosphonate users with and without AFFs had similar femoral structural geometries. Unlike in other populations, varus neck shaft angles were not found to be associated with AFFs in Asian female chronic bisphosphonate users. Thus, bone cross-sectional geometry is not likely to be associated with AFFs in Asian female chronic bisphosphonate users. Hip Structural Analysis does not show an increased predilection for tensile failure in AFFs.

Atypical Fractures are Mainly Subtrochanteric in Singapore and Diaphyseal in Sweden: A Cross-Sectional Study.

We have previously noted a dichotomy in the location of atypical fractures along the femoral shaft in Swedish patients, and a mainly subtrochanteric location of atypical fractures in descriptions of patients from Singapore. These unexpected differences were now investigated by testing the following hypotheses in a cross-sectional study: first, that there is a dichotomy also in Singapore; second, that the relation between subtrochanteric and diaphyseal location is different between the two countries; third, that the location is related to femoral bow. The previously published Swedish sample (n = 151) was re-measured, and a new Singaporean sample (n = 75) was established. Both samples were based on radiographic classification of all femoral fractures in women above 55 years of age. The distance between the fracture line and the lesser trochanter was measured. Femoral bow was classified as present or absent on frontal radiographs. Frequency distribution of the measured distances was analyzed using the Bayesian information criterion to choose the best description of the observed variable distribution in terms of a compilation of normally distributed subgroups. The analysis showed a clear dichotomy of the fracture location: either subtrochanteric or diaphyseal. Subtrochanteric fractures comprised 48% of all fractures in Singapore, and 17% in Sweden (p = 0.0001). In Singapore, femoral bow was associated with more fractures in the diaphyseal subgroup (p = 0.0001). This was not seen in Sweden. A dichotomous location of atypical fractures was confirmed, because it was found also in Singapore. The fractures showed a different localization pattern in the two countries. This difference may be linked to anatomical variations, but might also be related to cultural differences between the two populations that influence physical activity.

Diagnostic criteria of carpal tunnel syndrome using high-resolution ultrasonography: correlation with nerve conduction studies.

The aim of this work was to evaluate the diagnostic performance of grey-scale, color Doppler, and dynamic ultrasound (US) for diagnosing carpal tunnel syndrome (CTS) using the medical diagnostic test called nerve conduction study (NCS) as the reference standard, and to correlate the increase in median nerve (MN) cross-sectional area (CSA) with severity of CTS. Fifty-one patients (95 wrists) with clinical symptoms of idiopathic CTS were recruited. The CSA and flattening ratio of the MN were measured at the distal radio-ulnar joint, pisiform, and hamate levels; bowing of the flexor retinaculum was determined at the hamate level. The hypervascularity of the MN was evaluated. The transverse sliding of the MN was observed dynamically and recorded as being either normal or restricted/absent. Another 15 healthy volunteers (30 wrists) were recruited as controls. Interoperator reliability was established for all criteria. CTS was confirmed in 75 wrists (75/95: 79%; 14 minimal, 21 mild, 23 moderate, 17 severe). CSA at the pisiform level was found to be the most reliable and accurate grey-scale criterion to diagnose CTS (optimum threshold: 9.8 mm(2)). There was a good correlation between the severity of NCS and CSA (r = 0.78, p < 0.001). The sensitivity and specificity of color-Doppler and dynamic US in detecting CTS was 69, 95, 58, and 86%, respectively. Combination of these subjective criteria with CSA increases the sensitivity to 98.3%. US measurement of CSA provides additional information about the severity of MN involvement. Color-Doppler and dynamic US are useful supporting criteria that may expand the utility of US as a screening tool for CTS.

Review: epidemiology and pathophysiology of atypical femur fractures.

The recent recognition of the clinical phenomenon of atypical femoral fractures has garnered significant scientific interest. In this review, we will discuss and summarize the salient developments in the current understanding of the epidemiology, pathophysiology, and radiology of atypical femoral fractures.

Atypical femoral fractures: transverse morphology at lateral cortex is a critical feature.

In 2010, the American Society for Bone and Mineral Research (ASBMR) task force defined major and minor features to assist in the case finding and reporting of atypical femoral fractures (AFFs). One major feature that was proposed was a "transverse or short oblique configuration." Our primary aim was to compare the conventional overall fracture morphology (OFM) with its associated angle (OFMA) and our proposed lateral cortical fracture angle (LCFA) in the assessment of fracture configuration in suspected AFFs and non-AFFs. The radiographs of 79 patients with AFFs and 39 patients with non-AFFs were each analyzed by two blinded reviewers to obtain the OFM, OFMA, and LCFA. Using the overall fracture morphology to assess the suspected AFFs resulted in discordance between reviewers in 18 cases (22.8%), of which 5 (6.3%) were discordant between short oblique (>30° to 60°) and long oblique (>60° to 90°) configurations, therefore affecting their classifications as AFFs. By assessing only the critical component within the lateral cortex, all the suspected AFFs fell well within the classification as transverse fractures with a mean LCFA of 4.8° (range 0.3 to 18.0, SD = 4.23). The inter-reader variability was also lower for LCFA versus OFMA (4.1° versus 6.9°, p = 0.001) when used to assess AFFs. Fracture angles were significantly different in AFFs versus non-AFFs regardless of whether the OFMA or LCFA methodology was employed, but the greater difference associated with LCFA suggests its greater discriminating power. When LCFA was used in conjunction with 0° to 30° as the criteria for transverse morphology, all the AFFs and non-AFFs were correctly classified. By using a standardized and precise method in measuring the fracture angle, specifically using only the component of the lateral cortex and limiting to truly transverse fractures, ie, between 0° and 30°, the LCFA is a robust and accurate method to assess the fracture morphology in suspected AFFs.

Radiographic features of multifocal endosteal thickening of the femur in patients on long-term bisphosphonate therapy.

OBJECTIVES: To describe the characteristics of multifocal endosteal thickening in patients on bisphosphonate therapy. METHOD: A retrospective study of 68 patients with atypical femoral fractures (as defined by ASBMR) whilst on bisphosphonate therapy was performed. Femoral radiographs were assessed for: focal endosteal thickening, number of lesions, lesion location, femoral bowing, periosteal beak and black line. Medical records were reviewed to obtain relevant clinical data. RESULTS: Forty-eight lesions with multifocal endosteal thickening were detected in seven patients (2 unilateral, 5 bilateral), affecting 11.8 % of femora. Location was mainly diaphyseal (95.8 %), upper (10.4 %), middle (58.3 %) and lower femur (31.3 %), involving the lateral (85.4 %), anterior (6.3 %), anterolateral (2.1 %) and posterior cortices (6.3 %). Femoral bowing was present in 85.7 %. Associated findings of a periosteal beak and/or a black line, seen in 14.6 %, were associated with increased fracture risk (100.0 % sensitivity, 93.2 % specificity). CONCLUSIONS: Multifocal endosteal thickening is a new finding seen in patients with low bone mineral density on bisphosphonate therapy. They are rare, frequently bilateral, predominantly diaphyseal in location involving the lateral cortex and often associated with bowing. Caution is advised when seen in association with periosteal beak and/or black line because of a high rate of progression to complete fracture.

Bisphosphonate-related femoral periosteal stress reactions: scoring system based on radiographic and MRI findings.

OBJECTIVE: The purpose of this study was to review the radiographic and MRI findings of bisphosphonate-related femoral periosteal stress reactions to propose a scoring system for predicting symptoms and fracture risk. MATERIALS AND METHODS: A retrospective study included patients undergoing long-term bisphosphonate therapy who had radiographic evidence of focal femoral periosteal thickening on radiographs and MR images. There were 43 femoral periosteal stress reactions in 33 patients; eight patients underwent MRI. Radiographs and MR images were evaluated for focal cortical thickening (periosteal and endosteal), bone edema, focal cortical abnormalities (radiolucency, striations, cavities), and dreaded black line. The radiographic score (derived with statistical methods) and simple scores (simple radiographic, MRI, and combined scores) were compared with symptoms and fracture outcome. RESULTS: Logistic regression analysis showed an association between radiographic dreaded black line and symptoms (odds ratio, 68.0). Kaplan-Meier and Cox regression analyses showed radiographic dreaded black line (p < 0.0005; hazard ratio, 27.3) and focal cortical radiolucency (p = 0.011; hazard ratio, 6.8) were independent predictors of fracture. The survival score derived from Cox regression coefficients showed good separation of high- and low-risk groups. Mann-Whitney tests showed an association between MRI and combined scores and symptoms (p = 0.036, p = 0.036). The area under the receiver operating characteristic curve suggested better association with symptoms for MRI and combined scores than for simple radiographic scores (1.00, 1.00, 0.93). CONCLUSION: In bisphosphonate-related femoral periosteal stress reactions, radiographic dreaded black line and MRI and combined scores were associated with symptoms, and radiographic survival score was predictive of fracture risk. The relation between MRI and combined scores and fracture was not statistically significant.