Anatomical axes of the proximal and distal halves of the femur in a normally aligned healthy population: implications for surgery.

BACKGROUND: The anatomical axis of the femur is crucial for determining the correct alignment in corrective osteotomies of the knee, total knee arthroplasty (TKA), and retrograde and antegrade femoral intramedullary nailing (IMN). The aim of this study was to propose the concept of different anatomical axes for the proximal and distal parts of the femur; compare these axes in normally aligned subjects and also to propose the clinical application of these axes. METHODS: In this cross-sectional study, the horizontal distances between the anatomical axis of the proximal and distal halves of the femur and the center of the intercondylar notch were measured in 100 normally aligned femurs using standard full length alignment view X-rays. RESULTS: The average age was 34.44 ± 11.14 years. The average distance from the proximal anatomical axis to the center of the intercondylar notch was 6.68 ± 5.23 mm. The proximal anatomical axis of femur passed lateral to the center of the intercondylar notch in 12 cases (12%), medial in 84 cases (84%) and exactly central in 4 cases (4%). The average distance from the distal anatomical axis to the center of the intercondylar notch was 3.63 ± 2.09 mm. The distal anatomical axis of the femur passed medially to the center of the intercondylar notch in 82 cases (82%) and exactly central in 18 cases (18%). There was a significant difference between the anatomical axis of the proximal and distal parts of the femur in reference to the center of intercondylar notch (P value < 0.05), supporting the hypothesis that anatomical axes of the proximal and distal halves of the femur are different in the coronal plane. CONCLUSIONS: While surgeons are aware that the anatomical axis of the distal part of the femur is different than the anatomical axis of the proximal part in patients with femoral deformities, we have shown that these axes are also different in the normally aligned healthy people due to the anatomy of the femur in coronal plane. Also the normal ranges provided here can be used as a reference for the alignment guide entry point in TKA and antegrade and retrograde intramedullary femoral nailing.

ACR Appropriateness Criteria® Imaging After Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is the most commonly performed joint replacement procedure in the United States and annual demand for primary TKA is expected to grow by 673% by 2030. The first part provides an overview of imaging modalities (radiographs, CT, MRI, ultrasound, and various nuclear medicine studies) and discusses their usefulness in the imaging evaluation of TKA. The second part focuses on evidence-based imaging and imaging-guided intervention algorithms for the workup of TKA and its complications, including routine follow-up, component wear, periprosthetic infection, aseptic loosening, granulomas/osteolysis, conventional and rotational instability, periprosthetic fracture, patellar complications, and a variety of periprosthetic soft tissue abnormalities. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Osteoporosis and Bone Mineral Density.

Osteoporosis is a considerable public health risk, with 50% of women and 20% of men >50 years of age experiencing fracture, with mortality rates of 20% within the first year. Dual x-ray absorptiometry (DXA) is the primary diagnostic modality by which to screen women >65 years of age and men >70 years of age for osteoporosis. In postmenopausal women <65 years of age with additional risk factors for fracture, DXA is recommended. Some patients with bone mineral density above the threshold for treatment may qualify for treatment on the basis of vertebral body fractures detected through a vertebral fracture assessment scan, a lateral spine equivalent generated from a commercial DXA machine. Quantitative CT is useful in patients with advanced degenerative bony changes in their spines. New technologies such as trabecular bone score represent an emerging role for qualitative assessment of bone in clinical practice. It is critical that both radiologists and referring providers consider osteoporosis in their patients, thereby reducing substantial morbidity, mortality, and cost to the health care system. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Stress (Fatigue/Insufficiency) Fracture, Including Sacrum, Excluding Other Vertebrae.

Stress fractures, including both fatigue and insufficiency types, are frequently encountered in clinical practice as a source of pain in both athletes and patients with predisposing conditions. Radiography is the imaging modality of choice for baseline diagnosis. MRI has greatly improved our ability to diagnose radiographically occult stress fractures. Tc-99m bone scan and CT may also be useful as diagnostic tools. Although fatigue and insufficiency fractures can be self-limited and go onto healing even without diagnosis, there is usually value in initiating prompt therapeutic measures as incomplete stress fractures have the potential of progressing to completion and requiring more invasive treatment or delay in return to activity. This is particularly important in the setting of stress fractures of the femoral neck. Accuracy in the identification of these injuries is also relevant because the differential diagnosis includes entities that would otherwise be treated significantly different (ie, osteoid osteoma, osteomyelitis, and metastasis). The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Chronic Extremity Joint Pain-Suspected Inflammatory Arthritis.

Evaluation for suspected inflammatory arthritis as a cause for chronic extremity joint pain often relies on imaging. This review first discusses the characteristic osseous and soft tissue abnormalities seen with inflammatory arthritis and how they may be imaged. It is essential that imaging results are interpreted in the context of clinical and serologic results to add specificity as there is significant overlap of imaging findings among the various types of arthritis. This review provides recommendations for imaging evaluation of specific types of inflammatory arthritis, including rheumatoid arthritis, seronegative spondyloarthropathy, gout, calcium pyrophosphate dihydrate disease (or pseudogout), and erosive osteoarthritis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Accuracy and Measurement Error of the Medial Clear Space of the Ankle.

BACKGROUND: Measurement of the medial clear space (MCS) is commonly used to assess deltoid ligament competency and mortise stability when managing ankle fractures. Lacking knowledge of the true anatomic width measured, previous studies have been unable to measure accuracy of measurement. The purpose of this study was to determine MCS measurement error and accuracy and any influencing factors. METHODS: Using 3 normal transtibial ankle cadaver specimens, deltoid and syndesmotic ligaments were transected and the mortise widened and affixed at a width of 6 mm (specimen 1) and 4 mm (specimen 2). The mortise was left intact in specimen 3. Radiographs were obtained of each cadaver at varying degrees of rotation. Radiographs were randomized, and providers measured the MCS using a standardized technique. RESULTS: Lack of accuracy as well as lack of precision in measurement of the medial clear space compared to a known anatomic value was present for all 3 specimens tested. There were no significant differences in mean delta with regard to level of training for specimens 1 and 2; however, with specimen 3, staff physicians showed increased measurement accuracy compared with trainees. CONCLUSION: Accuracy and precision of MCS measurements are poor. Provider experience did not appear to influence accuracy and precision of measurements for the displaced mortise. CLINICAL RELEVANCE: This high degree of measurement error and lack of precision should be considered when deciding treatment options based on MCS measurements.

MR Imaging of Common Soft Tissue Masses in the Foot and Ankle.

Soft tissue masses may be encountered in the foot and ankle and may represent true neoplasms, malignant or benign, or other, nonneoplastic entities that mimic musculoskeletal tumors. This article reviews common soft tissue masses encountered in the foot or ankle, highlights their MR imaging appearance, and outlines common pitfalls. Technical considerations for imaging soft tissue masses in the foot and ankle are discussed. On MR imaging, T1-weighted and T2-weighted signal intensity, contrast enhancement characteristics, and lesion location, together with patient demographics, history and physical examination, and findings on radiographs, can be useful in characterizing masses in the foot and ankle.

ACR Appropriateness Criteria Imaging After Shoulder Arthroplasty.

There has been a rapid increase in the number of shoulder arthroplasties, including partial or complete humeral head resurfacing, hemiarthroplasty, total shoulder arthroplasty, and reverse total shoulder arthroplasty, performed in the United States over the past two decades. Imaging can play an important role in diagnosing the complications that can occur in the setting of these shoulder arthroplasties. This review is divided into two parts. The first part provides a general discussion of various imaging modalities, comprising radiography, CT, MRI, ultrasound, and nuclear medicine, and their role in providing useful, treatment-guiding information. The second part focuses on the most appropriate imaging algorithms for shoulder arthroplasty complications such as aseptic loosening, infection, fracture, rotator cuff tendon tear, and nerve injury. The evidence-based ACR Appropriateness Criteria guidelines offered in this report were reached via an extensive analysis of current medical literature from peer-reviewed journals and the application of well-established methodologies (the RAND/UCLA Appropriateness Method and the Grading of Recommendations Assessment, Development, and Evaluation) for rating the appropriateness of imaging and treatment procedures for specific clinical scenarios. Further analysis and review of the guidelines were performed by a multidisciplinary expert panel. In those instances in which there was insufficient or equivocal data for recommending the appropriate imaging algorithm, expert opinion may have supplemented the available evidence.

ACR Appropriateness Criteria Osteonecrosis of the Hip.

Osteonecrosis of the hip (Legg-Calvé-Perthes) is a common disease, with 10,000-20,000 symptomatic cases annually in the United States. The disorder affects both adults and children and is most frequently associated with trauma and corticosteroid usage. The initial imaging evaluation of suspected hip osteonecrosis is done using radiography. MRI is the most sensitive and specific imaging modality for diagnosis of osteonecrosis of the hip. The clinical significance of hip osteonecrosis is dependent on its potential for articular collapse. The likelihood of articular collapse is significantly increased with involvement of greater than 30%-50% of the femoral head area, which is optimally evaluated by MRI, often in the sagittal plane. Contrast-enhanced MRI may be needed to detect early osteonecrosis of the hip in pediatric patients, revealing hypoperfusion. In patients with a contraindication for MRI, use of either CT or bone scintigraphy with SPECT (single-photon emission CT) are alternative radiologic methods of assessment. Imaging helps guide treatment, which may include core decompression, osteotomy, and ultimately, need for joint replacement. The ACR Appropriateness Criteria(®) are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Improving Safety through Human Factors Engineering.

Human factors engineering (HFE) focuses on the design and analysis of interactive systems that involve people, technical equipment, and work environment. HFE is informed by knowledge of human characteristics. It complements existing patient safety efforts by specifically taking into consideration that, as humans, frontline staff will inevitably make mistakes. Therefore, the systems with which they interact should be designed for the anticipation and mitigation of human errors. The goal of HFE is to optimize the interaction of humans with their work environment and technical equipment to maximize safety and efficiency. Special safeguards include usability testing, standardization of processes, and use of checklists and forcing functions. However, the effectiveness of the safety program and resiliency of the organization depend on timely reporting of all safety events independent of patient harm, including perceived potential risks, bad outcomes that occur even when proper protocols have been followed, and episodes of "improvisation" when formal guidelines are found not to exist. Therefore, an institution must adopt a robust culture of safety, where the focus is shifted from blaming individuals for errors to preventing future errors, and where barriers to speaking up-including barriers introduced by steep authority gradients-are minimized. This requires creation of formal guidelines to address safety concerns, establishment of unified teams with open communication and shared responsibility for patient safety, and education of managers and senior physicians to perceive the reporting of safety concerns as a benefit rather than a threat.

Spectrum and detection of musculoskeletal findings on trauma-related CT torso examinations.

This study aims (1) to evaluate the spectrum of musculoskeletal (MSK) findings detected on trauma-related torso CT exams performed in the emergency department and (2) to identify the findings of high clinical importance that are underreported. Following IRB approval, two fellowship-trained MSK radiologists independently reviewed 200 consecutive trauma CT torso examinations performed at a level 1 trauma center, focusing on MSK findings. Discrepancies were resolved by consensus. Findings were categorized as of high, moderate, or low clinical importance based on criteria established with an orthopedic trauma surgeon. Findings evident on only one series (scout, axial, or sagittal/coronal reformations) were documented. The consensus reading was compared to the final report. Unreported findings of high clinical importance were entered into our departmental QA system. Eighty-two percent (164/200) of the studies had at least one MSK finding. There were 433 total findings of varying importance and the overall detection rate was 61 % (266/433). The detection rate for high importance findings was 80 % (177/221) with the majority representing acute fractures (99 %). For findings of high clinical importance, the lowest detection rates were for fractures of the sternum, proximal humerus, and forearm. Of the high severity findings, 6.3 % (14/221) were detected only on sagittal or coronal reformatted or scout images. Twenty percent of musculoskeletal findings of high clinical importance on trauma-related CT torso exams were not reported. Fractures of the sternum, proximal humerus, and forearm were the most commonly missed fractures and review of scout and multiplanar reformations can increase detection.

Image guided core needle biopsy of musculoskeletal lesions: are nondiagnostic results clinically useful?

BACKGROUND: The clinical utility of nondiagnostic core needle biopsies is not fully understood. Understanding the clinical and radiologic factors associated with nondiagnostic core needle biopsies may help determine the utility of these nondiagnostic biopsies and guide clinical decision making. QUESTIONS/PURPOSES: We asked (1) whether benign or malignant bone and soft tissue lesions have a higher rate of nondiagnostic core needle biopsy results, and which diagnoses have the lowest diagnostic yield; (2) how often nondiagnostic results affected clinical decision-making; and (3) what clinical factors are associated with nondiagnostic but useful core needle biopsies. METHODS: A retrospective study was performed of 778 consecutive image-guided core needle biopsies of bone and soft tissue lesions referred to the musculoskeletal radiology department at a single institution. The reference standard was (1) the final diagnosis at surgery or (2) clinical followup. Diagnostic yield was calculated for the most common diagnoses. Clinical and imaging features related to each nondiagnostic core needle biopsy were assessed for their association with clinical usefulness. Useful nondiagnostic biopsies were defined as those that help guide treatment. Each lesion was assessed before biopsy by the orthopaedic oncologist as (1) "likely to be benign" or (2) "suspicious for malignancy." The overall diagnostic yield was 74%. RESULTS: Malignant lesions had higher diagnostic yield than benign lesions: 94% (323 of 345) versus 58% (252 of 433), yielding a relative risk (RR) of 1.61 and 95% CI of 1.48 to 1.75. Soft tissue lesions had a higher diagnostic yield than bone lesions: 82% (291 of 355) versus 67% (284 of 423); RR, 1.22; 95% CI, 1.22 (1.12-1.33). Ganglion cyst (36%, four of 11), myositis ossificans (40%, two of five), Langerhans cell histiocytosis (0%, 0 of four), and simple bone cyst 0%, 0 of six) had the lowest diagnostic yield. Of the nondiagnostic biopsies assessed for clinical usefulness by the orthopaedic oncologist, 60% (85 of 142) of the biopsies were useful in guiding clinical decision making. Useful nondiagnostic core needle biopsy results occurred more often in painless, nonaggressive lesions, assessed as "likely to be benign" before biopsy. CONCLUSIONS: Nondiagnostic core needle biopsy results in musculoskeletal lesions are not entirely useless. At times, they can be supportive of benign processes and can help avert unnecessary surgical procedures.

A needs assessment of musculoskeletal fellowship training: a survey of practicing musculoskeletal radiologists.

OBJECTIVE: The purpose of this study was to conduct a needs assessment of musculo-skeletal radiologists regarding their musculoskeletal training experience and attitude toward a standardized musculoskeletal fellowship curriculum. MATERIALS AND METHODS: An anonymous survey was sent to the Society of Skeletal Radiology membership querying musculoskeletal radiologists' practice patterns, fellowship program, curriculum, and modes of learning. RESULTS: Of 216 respondents (26% response rate), 87% were musculoskeletal fellowship trained. The majority performed MRI, CT, and radiography (99%); arthrography (95%); spine MRI (77%); pediatric musculoskeletal imaging (75%); musculoskeletal ultrasound (63%); and biopsies (62%). During fellowship, 72% read spine MRI; 74% pediatric musculo-skeletal imaging, and 49% musculoskeletal ultrasound (49%); 33% received no spine procedural training. Most felt comfortable performing arthrography, joint injections, and bone and soft-tissue biopsies but not spine biopsies. Of the total, 33% received a curriculum and 67% had no formal feedback and 56% did not evaluate their program. The highest rated program features were teaching by attending physicians (69%), case variety (54%), and procedural training (49%). The lowest rated features were lack of curriculum (57%), lack of structured learning (48%), and lack of mentoring (24%). The favorite mode of learning was one-on-one readout with attending physicians (90%), and 85% agreed that a standardized musculoskeletal fellowship curriculum would benefit musculoskeletal training. CONCLUSION: Although musculoskeletal radiologists believe they were adequately trained for practice, there are perceived deficiencies in spine MRI, pediatric musculoskeletal imaging, and musculoskeletal ultrasound. A standardized musculoskeletal fellowship curriculum would provide improved structure and a defined educational program. Clear expectations, performance assessment, feedback, and programmatic evaluation should be core elements of the training of every musculoskeletal fellow.

On-call musculoskeletal radiographs: discrepancy rates between radiology residents and musculoskeletal radiologists.

OBJECTIVE: The purpose of this study was to determine the rate of discrepancy between radiology residents and attending musculoskeletal radiologists in interpretation of on-call musculoskeletal radiographs. MATERIALS AND METHODS: We performed a retrospective review of 2219 consecutive musculoskeletal radiology reports on patients who visited the emergency department between January 2009 and December 2010. The images were initially interpreted overnight by on-call residents (postgraduate years 3-5), and a final interpretation was rendered the next morning by a musculoskeletal radiologist. The reports were evaluated for major discrepancies, such as missed fractures, osteomyelitis, foreign bodies, tumors, and acute arthritic conditions, which were defined as cases in which a change in clinical management was needed and required notification of the emergency care provider. RESULTS: The overall discrepancy rate was 1.8% (40/2219). Fractures accounted for 62.5% (25/40) of missed findings. Fractures involving the upper extremity, particularly the hand and wrist (2.2% [9/405]), were the most frequently missed. Radial fractures accounted for 50% (7/14) of the missed upper extremity fractures. Foreign bodies (10% [4/40]) and tumorlike lesions (7.5% [3/40]) accounted for the next most common misses. Finally, independent resident readings in the on-call setting had little adverse effect on patient care. CONCLUSION: In the on-call setting, the low discrepancy rate between interpretations of musculoskeletal radiographs by residents and by musculoskeletal attending radiologists is comparable to that reported for other body parts and modalities. Residents should be aware of the relatively high rate of missed pathologic findings in the upper extremity, especially the radius.

High-resolution proton density weighted three-dimensional fast spin echo (3D-FSE) of the knee with IDEAL at 1.5 Tesla: comparison with 3D-FSE and 2D-FSE--initial experience.

PURPOSE: To assess the feasibility of combining three-dimensional fast spin echo (3D-FSE) and Iterative-decomposition-of water-and-fat-with-echo asymmetry-and-least-squares-estimation (IDEAL) at 1.5 Tesla (T), generating a high-resolution 3D isotropic proton density-weighted image set with and without "fat-suppression" (FS) in a single acquisition, and to compare with 2D-FSE and 3D-FSE (without IDEAL). MATERIALS AND METHODS: Ten asymptomatic volunteers prospectively underwent sagittal 3D-FSE-IDEAL, 3D-FSE, and 2D-FSE sequences at 1.5T (slice thickness [ST]: 0.8 mm, 0.8 mm, and 3.5 mm, respectively). 3D-FSE and 2D-FSE were repeated with frequency-selective FS. Fluid, cartilage, and muscle signal-to-noise ratio (SNR) and fluid-cartilage contrast-to-noise ratio (CNR) were compared among sequences. Three blinded reviewers independently scored quality of menisci/cartilage depiction for all sequences. "Fat-suppression" was qualitatively scored and compared among sequences. RESULTS: 3D-FSE-IDEAL fluid-cartilage CNR was higher than in 2D-FSE (P < 0.05), not different from 3D-FSE (P = 0.31). There was no significant difference in fluid SNR among sequences. 2D-FSE cartilage SNR was higher than in 3D FSE-IDEAL (P < 0.05), not different to 3D-FSE (P = 0.059). 2D-FSE muscle SNR was higher than in 3D-FSE-IDEAL (P < 0.05) and 3D-FSE (P < 0.05). Good or excellent depiction of menisci/cartilage was achieved using 3D-FSE-IDEAL in the acquired sagittal and reformatted planes. Excellent, homogeneous "fat-suppression" was achieved using 3D-FSE-IDEAL, superior to FS-3D-FSE and FS-2D-FSE (P < 0.05). CONCLUSION: 3D FSE-IDEAL is a feasible approach to acquire multiplanar images of diagnostic quality, both with and without homogeneous "fat-suppression" from a single acquisition.

Clavicle and acromioclavicular joint injuries: a review of imaging, treatment, and complications.

Fractures of the clavicle account for 2.6-5% of all fractures. Clavicular fractures have traditionally been treated conservatively, however, there has recently been increased interest in surgical repair of displaced clavicular fractures, with resultant lower rates of nonunion and malunion. Treatment of acromioclavicular (AC) separation has traditionally been conservative, with surgery reserved for patients with chronic pain or significant dislocation and acute soft tissue injury. It is important for the radiologist to become familiar with the surgical techniques used to fixate these fractures as well as the post-operative appearance and potential complications.

A review of Charcot neuroarthropathy of the midfoot and hindfoot: what every radiologist needs to know.

Charcot neuroarthropathy (CN) occurs commonly in diabetic patients in the joints of the foot and ankle. Radiologists may be the first to suggest the diagnosis of CN and can facilitate prompt intervention and treatment if they are aware of the radiographic manifestations of CN and the signs of progression of disease. Radiologists should also become aware of the evolving treatment of the disease as focus is shifting toward early surgical intervention and limb salvage rather than amputation. Knowledge of preoperative assessment, the types of surgeries performed, and some of the encountered postoperative complications enable the radiologist to facilitate timely intervention by our surgical colleagues and be a valuable member of the management team.

A review of factors that affect artifact from metallic hardware on multi-row detector computed tomography.

Artifact arising from metallic hardware can present a major obstacle to computed tomographic imaging of bone and soft tissue and can preclude its use for answering a variety of important clinical questions. The advent of multirow detector computed tomography offers new opportunities to address the challenge of imaging in the presence of metallic hardware. This pictorial essay highlights current strategies for reducing metallic hardware artifacts and presents some illustrative clinical cases.