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The purposes of this study was to determine the prevalence of the accessory anterolateral talar facet (AALTF); to evaluate the relationship between AALTF, focal abutting bone marrow edema (FABME), and sinus tarsi edema; and to study the prevalence of tarsal coalitions in patients with the AALTF utilizing ankle MR images. 5-T ankle MR images were reviewed for the presence of AALTF, FABME, sinus tarsi edema, tarsal coalition, and location and type of coalition (cartilaginous, fibrous, and osseous). Multivariate analysis was performed to examine the correlation between AALTF and the other variables. Three hundred ninety-one consecutive patients were included (age range 5–86 years; mean age 45 years). An AALTF was present in 3.6% (14/391) of patients. The AALTF prevalence was 2% in women and 6.6% in men. There was a significantly association between AALTF and FABME (9/14, p < 0.05), sinus tarsi edema (13/14, p < 0.05), and tarsal coalition (4/14, p < 0.05). AALTF is relatively often detected on MRI of the ankle and significantly associated with BME, sinus tarsi edema, and subtalar coalition. Patients with a tarsal coalition should be evaluated for the concurrent presence of an AALTF.

A cohort of adult acquired flatfoot deformity rigid-body models was developed to investigate the effects of isolated tendon transfer with successive levels of medializing calcaneal osteotomy (MCO). Following IRB approval, six diagnosed flatfoot sufferers were subjected to magnetic resonance imaging (MRI) and their scans used to derive patient-specific models. Single-leg stance was modeled, constrained solely through physiologic joint contact, passive soft-tissue tension, extrinsic muscle force, body weight, and without assumptions of idealized mechanical joints. Surgical effect was quantified using simulated mediolateral (ML) and anteroposterior (AP) X-rays, pedobarography, soft-tissue strains, and joint contact force. Radiographic changes varied across states with the largest average improvements for the tendon transfer (TT) + 10 mm MCO state evidenced through ML and AP talo-1st metatarsal angles. Interestingly, 12 of 14 measures showed increased deformity following TT-only, though all increases disappeared with inclusion of MCO. Plantar force distributions showed medial forefoot offloading concomitant with increases laterally such that the most corrected state had 9.0% greater lateral load. Predicted alterations in spring, deltoid, and plantar fascia soft-tissue strain agreed with prior cadaveric and computational works suggesting decreased strain medially with successive surgical repair. Finally, joint contact force demonstrated consistent medial offloading concomitant with variable increases laterally. Rigid-body modeling thus offers novel advantages for the investigation of foot/ankle biomechanics not easily measured in vivo.

Six patients were retrospectively identified as having undergone lateral ligament reconstruction surgery. The surgical procedures were categorized into four groups: direct lateral ligament repair, peroneus brevis tendon rerouting, peroneus brevis tendon loop, and peroneus brevis tendon split and rerouting. At radiography and magnetic resonance (MR) imaging, the presence of one or more suture anchors in the region of the anterior talofibular ligament indicates direct ligament repair, whereas a fibular tunnel indicates peroneus brevis tendon rerouting or loop. Both ultrasonography (US) and MR imaging demonstrate rerouted tendons as part of lateral ankle reconstruction; however, MR imaging can also depict the rerouted tendon within an osseous tunnel if present, especially if T1-weighted sequences are used. Artifact from suture material may obscure the tendon at MR imaging but not at US. With both modalities, the integrity of the rerouted peroneus brevis tendon is best evaluated by following the tendon proximally from its distal attachment site, which typically remains unchanged. The rerouted tendon or portion of the tendon can then be traced proximally to its reattachment site. Familiarity with the surgical procedures most commonly used for lateral ankle ligament reconstruction, and with the imaging features of these procedures, is essential for avoiding diagnostic pitfalls and ensuring accurate assessment of the ligament reconstruction.

We present a case of traumatic bamboo foreign body penetration through the posterior thigh extending cephalad into the pelvis sustained during skiing. The unsuspected bamboo foreign body was missed prospectively on the initial portable trauma radiograph of the pelvis, but was retrospectively quite apparent as a linear 12 x 2-cm radiolucent region overlying the left pelvis and hip region. On CT examination, the bamboo stick appeared as a round cylindrical air-filled structure of high density compared to soft tissue - the typical appearance of bamboo. Bamboo foreign bodies can be recognized radiographically by this typical appearance, since it is one of the few wood products that causes high attenuation relative to soft tissue on CT.

The objective of our study was to sonographically characterize the dorsal aspect of the scapholunate ligament in cadaveric wrists using arthrography, MR arthrography, and anatomic correlation as the gold standard.The dorsal aspect of the scapholunate ligament in four cadaveric wrists was evaluated on sonography without knowledge of the findings from standard arthrography, MR arthrography, and anatomic sectioning. The sonographic findings were compared with the findings from other modalities. The criteria for an abnormal scapholunate ligament included an abnormal contrast communication between the radiocarpal and midcarpal joints on arthrography and a discontinuity of the dorsal aspect of the scapholunate ligament that was documented both on MR arthrography and at anatomic sectioning.Arthrography, MR arthrography, and anatomic sectioning showed the dorsal aspect of the scapholunate ligament to be normal in one specimen and abnormal in three specimens. On sonography, the normal scapholunate ligament was hyperechoic between the scaphoid and lunate bones. In the three cases of abnormality, a normal scapholunate ligament was not visualized, and an abnormal hypoechogenicity was present.The dorsal aspect of the scapholunate ligament can be depicted on sonography; abnormality is present in patients in whom the normally hyperechoic fibrillar ligament is hypoechoic or absent.

Background: The inherently complex three-dimensional morphology of both the pelvis and acetabulum create difficulties in accurately determining acetabular orientation. Our objectives were to develop a reliable and accurate methodology for determining three-dimensional acetabular orientation and to utilize it to describe relevant characteristics of a large population of subjects without apparent hip pathology. Methods: High-resolution computed tomography studies of 200 patients previously receiving pelvic scans for indications not related to orthopaedic conditions were selected from our institution’s database. Three-dimensional models of each osseous pelvis were generated to extract specific anatomical data sets. A novel computational method was developed to determine standard measures of three-dimensional acetabular orientation within an automatically identified anterior pelvic plane reference frame. Automatically selected points on the osseous ridge of the acetabulum were used to generate a best-fit plane for describing acetabular orientation. Results: Our method showed excellent interobserver and intraobserver agreement (an intraclass correlation coefficient [ICC] of >0.999) and achieved high levels of accuracy. A significant difference between males and females in both anteversion (average, 3.5°; 95% confidence interval [CI], 1.9° to 5.1° across all angular definitions; p < 0.0001) and inclination (1.4°; 95% CI, 0.6° to 2.3° for anatomic angular definition; p < 0.002) was observed. Intrapatient asymmetry in anatomic measures showed bilateral differences in anteversion (maximum, 12.1°) and in inclination (maximum, 10.9°). Conclusions: Significant differences in acetabular orientation between the sexes can be detected only with accurate measurements that account for the entire acetabulum. While a wide range of interpatient acetabular orientations was observed, the majority of subjects had acetabula that were relatively symmetrical in both inclination and anteversion. Clinical Relevance: A highly accurate and reproducible method for determining the orientation of the acetabulum’s aperture will benefit both surgeons and patients, by further refining the distinctions between normal and abnormal hip characteristics. Enhanced understanding of the acetabulum could be useful in the diagnostic, planning, and execution stages for surgical procedures of the hip or in advancing the design of new implant systems.

Adult Acquired Flatfoot Deformity (AAFD) is a degenerative disease characterized by chronic changes in the joint alignment of the bones of the foot leading to significant pain and dysfunction. The hallmark of this disease is the functional loss in posterior tibialis tendon (PTT) strength though mechanical degradation of passive support structures of the foot have also been implicated, namely the spring ligament, talocalcaneal interosseous ligaments, fibers of the anterior deltoid, and the long and short plantar ligaments. [1] Clinically, AAFD patients present with midfoot collapse, forefoot abduction, and valgus tilting of the hindfoot and the magnitudes of these deformities are most often graded using plane radiographs in the mediolateral (ML), oblique anteroposterior (AP) and posteroanterior (PA) views. [1–3] The objective of this study was to develop a population of patient-matched rigid-body kinematic models using a standardized methodology that can be used to predict pathologic foot function with agreement between patient and model assessed through clinically relevant radiographic joint angles.Copyright © 2013 by ASME

The rotator interval and the long head of the biceps brachii tendon are anatomically closely associated structures believed to confer stability to the shoulder joint. Abnormalities of the rotator interval may be acquired or congenital and are associated with instability of the long head of the biceps brachii tendon. Clinical and arthroscopic diagnoses of rotator interval abnormalities and subtle instability patterns of the long head of the biceps brachii tendon are difficult. Magnetic resonance arthrography, owing to its superior depiction of ligaments with distention of the joint capsule, may be the procedure of choice, barring open surgery, for help in diagnosis of these conditions.

OBJECTIVE. We have found variability in the sonographic appearance of peripheral nerve sheath tumors. The purpose of this study was to characterize the sonographic appearances of pathologically proven peripheral nerve sheath tumors.CONCLUSION. Peripheral nerve sheath tumors are often hypoechoic with posterior acoustic enhancement and so may simulate a ganglion cyst. The presence of intrinsic blood flow on color Doppler sonography and peripheral nerve continuity suggests the diagnosis of peripheral nerve sheath tumor. Sonography cannot reliably distinguish neurofibromas from schwannomas.

To characterize the ultrasonographic (US) appearance of the anterior bundle of the ulnar collateral ligament of the elbow by comparing US images with magnetic resonance (MR) arthrograms and anatomic slices.The ulnar collateral ligament in four cadavers (eight elbows) was blindly evaluated with US by one musculoskeletal radiologist with experience in musculoskeletal US. These results were compared with standard arthrograms, MR arthrograms, and anatomic slices by consensus reading of two musculoskeletal radiologists. The criteria for an abnormal ulnar collateral ligament included contrast material extension into the ligament or fiber discontinuity, as documented by MR arthrography and anatomic slices.Standard arthrography, MR arthrography, and anatomic slices demonstrated the ulnar collateral ligament to be unequivocally normal in three specimens and abnormal in two. The remaining three elbows did not meet the criteria for classification as either normal or abnormal, and thus they were excluded from the study. With US, the normal ulnar collateral ligament was fibrillar and hyperechoic between the medial epicondyle and proximal ulna. In the two abnormal cases, abnormal hypoechogenicity and ligament fiber disruption were noted. In addition, the proximal aspect of the ulnar collateral ligament varied from a cordlike structure to a broad attachment to the undersurface of the medial epicondyle with variable fat.In this small sample, the anterior bundle of the ulnar collateral ligament is identified with US by its hyperechoic and compact fibrillar echotexture. The proximal attachment of the ulnar collateral ligament has a variable appearance. Hypoechogenicity and fiber disruption indicated ulnar collateral ligament abnormality.

Sports-related and overuse conditions may cause painful abnormalities that include muscle and tendon tears, tendon avulsion, bone remodeling, and stress fracture. Adductor insertion avulsion syndrome (AIAS), or thigh splints, is a stress-related avulsive injury of the adductor muscles that occurs at the posteromedial midfemoral diaphysis (Fig. 1). 1,2 Repetitive avulsive stresses in AIRS may result in a spectrum of findings, which include traction periostitis, osseous stress reaction, and stress fracture. 1 1 Bone scan findings in AIAS include linear uptake along the medial shaft of the femur. 3-5 The findings associated with AIAS on magnetic resonance (MR) imaging have been described recently 1,2 They include bone marrow edema, adjacent enhancing periostitis, and stress fracture of the posteromedial femoral diaphysis. 1,2 Musculoskeletal sonography is commonly used to evaluate muscle and tendon injury. 6 To our knowledge, the sonographic findings of AIAS have not been described. We present the sonographic findings in a patient with clinical and MR imaging evidence of AIAS.

Diffuse idiopathic skeletal hyperostosis is an ossifying diathesis that commonly affects the vertebral skeleton. Spinal ankylosis can occur, predisposing the spine to abnormal stresses and fracture. Fracture through an ankylosed segment with continued motion at the site of fracture can result in pseudoarthrosis. Pseudoarthrosis can also develop at the junction of the fused and mobile spine secondary to chronic abnormal stresses. This complication is manifest radiographically by single-level intervertebral disc space destruction, vertebral endplate erosions, marked vertebral sclerosis, and large osteophytes. The radiographic manifestations can mimic infective spondylitis or neuropathic changes.

OBJECTIVE. We describe the sonographic imaging characteristics of ankle ganglia with pathologic correlation in 10 patients.CONCLUSION. Foot and ankle ganglia exhibit a spectrum of sonographic appearances from round and completely anechoic masses to hypoechoic, multilobulated, multiseptated masses with dependent debris. All the ganglionic cysts examined in our study showed posterior acoustic enhancement without solid nodules on sonography.

1247 he sonographic appearance of ankle tendons, ligaments, joints, and other soft-tissue masses has recently been described [1–4]. Familiarity with the anatomic variants and knowledge of sonographic artifacts and pitfalls improves diagnostic yield and aids in treatment. In this article, we discuss a variety of artifacts, anatomic variants, and pitfalls that can simulate abnormality or injury and become a source of confusion and misdiagnosis. Pitfalls Associated with Technical Factors Artifacts Anisotropy is an artifact commonly seen when ligaments and tendons are examined Artifacts, Anatomic Variants, and Pitfalls in Sonography of the Foot and Ankle Smita Patel 1 , David P. Fessell 1 , Jon A. Jacobson 1 , Curtis W. Hayes 1 , Marnix T. van Holsbeeck 2

To evaluate the sonographic appearance of the peroneus quartus muscle.Thirty-two consecutive patients who underwent both sonography and magnetic resonance (MR) imaging of the lateral ankle were retrospectively identified during 42 months. Seven of these patients demonstrated a peroneus quartus muscle, with MR imaging as the standard of reference. The peroneus quartus muscle was characterized at retrospective review of sonographic images with regard to origin, insertion, echogenicity, and location.Of the seven peroneus quartus muscles, six originated from the peroneus brevis muscle, and all seven inserted onto the calcaneus. The muscle portion of the peroneus quartus muscle was hypoechoic, while the tendon portion was hyperechoic and fibrillar. The location of the peroneus quartus musculotendinous junction was variable. Hence, the appearance of the peroneus quartus muscle in the region of the distal fibula ranged from 100% muscle to 100% tendon.Variability in the appearance of the peroneus quartus muscle is common with sonography due to variation in the location of the musculotendinous junction. Recognition of these variations will allow correct diagnosis of a peroneus quartus muscle, and more important, it will allow differentiation from adjacent tendon abnormality.

Complex knee injuries are common, often resulting from multiple forces: varus, valgus, hyperextension, hyperflexion, internal rotation, external rotation, anterior or posterior translation, and axial load. Certain combinations of forces are known to cause specific injury patterns. After a review of the literature, the authors developed a mechanism-based classification system based on patterns of bone marrow edema and ligament injury for complex knee injuries depicted at magnetic resonance imaging. The classification system takes into account knee position and forces and recognition of patterns of bone injury and complementary soft-tissue injury. Ten mechanism-based injury patterns were recognized: (a) pure hyperextension, (b) hyperextension with varus, (c) hyperextension with valgus, (d) pure valgus, (e) pure varus, (f) flexion with valgus and external rotation, (g) flexion with varus and internal rotation, (h) flexion with posterior tibial translation, (i) patellar dislocation (flexion, valgus, and internal rotation of femur on fixed tibia), and (j) direct trauma. Recognition of these patterns may help assess the full extent of knee injury, particularly at the posterolateral and posteromedial corners of the knee.

OBJECTIVE. The flexor tendon pulley system is often ruptured when a flexed finger is forcibly extended. In the acute phase, soft-tissue swelling and pain often make clinical evaluation difficult. These pulleys are not constantly visualized on MR imaging. Rupture of the pulley system can be inferred by observing bow stringing of the underlying flexor tendons when MR imaging is obtained with the finger in flexion. Our objective is to describe the flexor tendon pulley system and present our MR technique.

In routine MRI of the knee, less attention frequently is paid to the patellofemoral joint and its surrounding structures than to the menisci and ligaments. This article reviews MRI of common abnormalities of the anterior aspect of the knee. Chondromalacia patellae, pathological softening of the patellar cartilage, can be diagnosed with reasonable accuracy with MRI using standard sequences. Abnormalities of alignment can be assessed grossly on static images, but more sophisticated evaluation of patellofemoral tracking requires the kinematic technique. Other traumatic or overuse injuries involving the extensor mechanism of the knee, such as the quadriceps and patellar tendons, are also reviewed briefly.

Fourteen freshly disarticulated knee specimens were studied to assess the usefulness of magnetic resonance (MR) imaging in the detection and correct staging of patellar chondral lesions. Axial and sagittal images were obtained; T1-weighted spin-echo sequences were found satisfactory for defining cartilage morphology. Specimens were sectioned and examined grossly for cartilage changes such as softening, blistering, fibrillation, fissuring, and frank subchondral bone exposure. In a side-by-side comparison, all lesions classified grossly in the Shahriaree system as stage II or higher showed MR changes. Stage I changes could not be identified in disarticulated specimens. Stage III lesions showed cartilage irregularity (ulceration) or a loss of the normal, sharply defined margin between coapted cartilage, which represented "crabmeat" fibrillation. Stage IV lesions showed ulceration to bone, sometimes with subchondral bone changes. In this in vitro, preliminary study, MR imaging was found to be an accurate means for detecting and staging moderate and advanced patellar cartilage lesions.

This article discusses the normal magnetic resonance (MR) appearance, functional anatomy, and biomechanics of the knee joint. Technical considerations of MR imaging of the knee are covered first: coil selection, positioning, and pulse sequences. Useful sequences for both routine examinations and specific clinical situations are suggested. This is followed by a discussion of the biomechanics and functional anatomy of the knee. The typical MR appearance of various key structures in the knee is discussed. The final section of the article is an atlas of normal MR anatomy of the knee, covering the sagittal, coronal, and axial planes.

Five cases of calcific tendinitis with radiographic evidence of cortical bone erosion are presented. All five cases arose at unusual sites: two at the pectoralis major insertion on the proximal humerus, two at the insertion of the gluteus maximus, and one at the insertion of the adductor magnus. Biopsy was performed in four cases and revealed areas of histiocytic infiltration, amorphous spherules of calcification, and areas of giant cell reaction extending into the cortex. To our knowledge, calcific tendinitis presenting with radiographic evidence of bone erosion has not been reported previously.

L'article decrit un cas unique de resorption totale du sesamoide lateral du gros orteil secondaire a une osteomyelite aigue a Pseudomonas aeruginosa chez un jeune homme de 15 ans, ce qui amene a ajouter l'osteomyelite aigue aux diagnostics differentiels