Varus Posteromedial Rotatory Instability of the Elbow: Injury Pattern and Surgical Experience of 27 Acute Consecutive Surgical Patients.

OBJECTIVES: To identify associated injuries that occur in varus posteromedial rotatory instability (VPMRI) of the elbow and present their surgical management. DESIGN: Level II retrospective study. SETTING: Tertiary referral center. PATIENT/PARTICIPANTS: Twenty-seven patients with VPMRI injuries treated surgically over an 8-year period. INTERVENTION: Open reduction and internal fixation of anteromedial coronoid facet fracture, lateral collateral ligament repair, and associated injured soft-tissue repairs. MAIN OUTCOME MEASURED: Radiographic classification, associated medial and lateral bony and soft-tissue injuries, surgical fixation method, and complications were recorded. RESULTS: According to the O'Driscoll classification, there were 15 (55%) type 2-2, 11 (41%) type 2-3, and 1 (4%) type 3-1 fractures. Lateral and medial collateral ligament tears were found in 100% and 63%, respectively. Common extensor and flexor origin injuries occurred in 19 (70%) and 2 (7%) elbows, respectively. A marginal radial head fracture was found in 1 patient. Most patients were treated with a combination of fixation methods. Complications occurred in 7 (26%) patients. CONCLUSIONS: This study documents both associated findings and surgical fixation methods. In all cases, the lateral collateral ligament was disrupted, often in association with an injured common extensor origin. Medial collateral ligament injuries are commonly involved. Radial head fractures are rarely associated. The surgeon should have a high index of suspicion if an isolated coronoid fracture is encountered. Clinical and functional outcome scores are needed in future studies to further inform treatment of VPMRI of the elbow. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Spinal curvature measurement by tracked ultrasound snapshots.

Monitoring spinal curvature in adolescent kyphoscoliosis requires regular radiographic examinations; however, the applied ionizing radiation increases the risk of cancer. Ultrasound imaging is favored over radiography because it does not emit ionizing radiation. Therefore, we tested an ultrasound system for spinal curvature measurement, with the help of spatial tracking of the ultrasound transducer. Tracked ultrasound was used to localize vertebral transverse processes as landmarks along the spine to measure curvature angles. The method was tested in two scoliotic spine models by localizing the same landmarks using both ultrasound and radiographic imaging and comparing the angles obtained. A close correlation was found between tracked ultrasound and radiographic curvature measurements. Differences between results of the two methods were 1.27 ± 0.84° (average ± SD) in an adult model and 0.96 ± 0.87° in a pediatric model. Our results suggest that tracked ultrasound may become a more tolerable and more accessible alternative to radiographic spine monitoring in adolescent kyphoscoliosis.

Resolution at oblique incidence angles of a flat panel imager for breast tomosynthesis.

Oblique incidence of x rays on an imaging detector causes blurring that reduces spatial resolution. For simple projection imaging this effect is small and often ignored. However, for breast tomosynthesis, the incidence angle can be larger (>20 degrees), leading to increased blur for some of the projections. The modulation transfer function (MTF) is measured for a typical phosphor-coupled flat-panel detector versus angular incidence of the x-ray beam for two x-ray spectra: 26 kV Mo/Mo and 40 kV Rh/Al. At an incidence angle of 40 degrees the MTF at 5 mm(-1) falls by 35% and 40% for each spectrum, respectively (and 65%/80% at 8 mm(-1)). Increasing the detector absorber thickness to achieve improved quantum efficiency will cause the blurring effect due to beam obliquity to become greater. The impact of this blur is likely to cause misregistration and increased relative noise in tomosynthesis reconstructed images.