Safety and image quality of MR-conditional external fixators for 1.5 Tesla extremity MR.

PURPOSE: To evaluate the safety and image quality of extremity MR examinations performed with two MR conditional external fixators located in the MR bore. MATERIALS AND METHODS: Single-center retrospective study of a prospectively maintained imaging dataset that evaluated MR examinations of extremities in patients managed with external fixations instrumentation and imaged on a single 1.5T MR scanner. The fixation device was one of two MR-conditional instrumentation systems: DuPuy Synthes (aluminum, stainless steel, carbonium and Kevlar) or Dolphix temporary fixation system (PEEK-CA30). Safety events were recorded by the performing MR radiologic technologist. A study musculoskeletal radiologist assessed all sequences to evaluate for image quality, signal- and contrast-to-noise ratios (SNR/CNR), and injury patterns/findings. RESULTS: In the 13 men and 9 women with a mean age of 42 years (range 18 to 72 years), most patients (19/22 patients; 86%) were involved with trauma resulting in extremity injury requiring external fixation. MR examinations included 19 knee, 2 ankle, and 1 elbow examinations. There were no adverse safety events, heating that caused patient discomfort, fixation dislodgement/perturbment, or early termination of MR examinations. All examinations were of diagnostic quality. Fat-suppressed proton density sequences had significantly higher SNR and CNR compared to STIR (p = 0.01 to 0.04). The lower SNR of STIR and increased quality of fat-suppressed proton density during the study period led to the STIR sequence being dropped in standard MR protocol. CONCLUSION: MR of the extremity using the two study MR conditional external fixators within the MR bore is safe and feasible.

Correction to: Ultrasound localization of lacerated flexor tendon ends in the hand: a cadaveric study.

In the results section of the abstract, it states "99.0% (n = 05/96 tendons)" when it should state "99.0% (n = 95/96 tendons)".

Ultrasound localization of lacerated flexor tendon ends in the hand: a cadaveric study.

OBJECTIVE: Flexor tendon repair currently requires extensive exposure to locate and repair tendons. Ultrasound (US) has been used to identify lacerated tendon ends with little information on accuracy. This study was designed to measure the accuracy of US to localize tendon ends in zone II flexor tendon lacerations in a cadaveric model. MATERIALS AND METHODS: US was used to locate tendon ends in zone II lacerations of fingers of six cadaveric hands (96 tendon ends) by a musculoskeletal radiologist. The distance of each tendon end relative to the laceration was recorded. Specimens were dissected and tendon position was compared to US position. RESULTS: The radiologist correctly identified full-thickness lacerations of both superficial and deep tendons 99.0% (n = 05/96 tendons) of the time. The average difference between mean US predicted retraction and anatomic confirmed retraction for all digits all tendons was 3.5 mm of underestimation. US correctly identified the position of all tendon stumps to within 10 mm 92.7% (n = 89/96 tendons) of the time and 69.8% (n = 67/96 tendons) of the time to within 5 mm. Error tended to underestimate (61.5%; 59/96 tendons) rather than overestimate retraction (29.2%; 28/96 tendons). CONCLUSIONS: This fresh cadaveric study has demonstrated that with an experienced radiologist, there was 99.0% accuracy identifying a completed tendon tear and locating the tendon ends with US to within 1 cm was 92.7% accurate.

Tendon entrapments and dislocations in ankle and hindfoot fractures: evaluation with multidetector computed tomography.

The purpose of this study was to assess the incidence of tendon entrapments and tendon dislocations associated with ankle and hindfoot fractures in patients studied by multidetector computed tomography (MDCT). Additionally, we describe particular tendon injuries associated with specific fractures. This was a retrospective review of all individuals with a trauma-protocol CT for suspected ankle and/or hindfoot fractures during a consecutive 41-month time period at a single Level I Trauma Center. Each patient's images were evaluated by two radiologists and an orthopedic surgeon for tendon entrapment, tendon dislocation, and bone(s) fractured or dislocated. There were 398 patients with ankle and/or hindfoot fractures that showed tendon entrapment or dislocation in 64 (16.1 %) patients. There were 30 (46.9 %) patients with 40 tendon entrapments, 31 (48.4 %) patients with 59 tendon dislocations, and three (4.7 %) patients with both tendon entrapment and dislocation. All patients with tendon entrapments were seen with either pilon fractures and/or a combination of posterior, medial, or lateral malleolar fractures. The most frequently entrapped tendon was the posterior tibialis tendon (PTT) in 27 patients (27/30, 90.0 %). The peroneal tendons were the most frequently dislocated, representing 27 (87.1 %) of patients with tendon dislocation; all resulted from a talar or calcaneal fracture or subluxation. This study demonstrates that tendon entrapments and tendon dislocations are commonly seen in complex fractures of the ankle and hindfoot. Pilon fractures were associated with the majority of tendon entrapments, whereas calcaneus fractures were associated with the majority of tendon dislocations.

A clearly observable cold fracture line of an early occult hip fracture on bone scintigraphy.

Although a true fracture is commonly associated with increased radionuclide uptake on bone scintigraphy, it is also possible for an area with no increased uptake (a cold line) to indicate fracture, as demonstrated in this case study. Detection of an occult acute hip fracture through recognition of a cold fracture line is important because of the associated therapeutic, economic, and medicolegal implications.

Anatomic guide and sonography for surgical repair of leg muscle lacerations.

BACKGROUND: There were over 110,000 leg laceration cases reported in the United States in 2011. Currently, muscle laceration is repaired by suturing epimysium to epimysium. Tendon-to-tendon repair is stronger, restores the muscle's resting length, and leads to a better functional recovery. Tendons retract into the muscle belly following laceration and surgeons have a difficult time finding them. Many surgeons are unfamiliar with leg muscle anatomy and the fact that the leg muscles have long intramuscular tendons that are not visible in situ. A surgical anatomic guide exists to help surgeons locate forearm tendons; no such guide exists for tendons in the leg. MATERIALS AND METHODS: The leg tendon ends of 11 cadavers were dissected, measured, and recorded as percentages of leg length. High-frequency ultrasound was used to locate tendon ends in three additional cadavers. These locations were compared with the actual tendon ends located via dissection. RESULTS: There was little variation in tendon end position within the cadaver group, between men and women or right and left legs. The data are presented as an anatomic guide to inform surgeons of the tendon ends' likely locations in the leg. CONCLUSION: The location of leg intramuscular tendon ends is predictable and the anatomic guide will help surgeons locate tendon ends and perform tendon-to-tendon repairs. Ultrasound is a potentially effective tool for detection of accurate location of repairable tendon ends in leg muscle lacerations.

Lesión de SLAP: evaluación mediante RM dinámica y artrorm dinámica / Superior labrum anteroposterior (SLAP) lesion: evaluation with dynamic MRI and MR-arthrography

Propósito: presentar nuestra experiencia en pacientes con inestabilidad articular de hombro y RM convencional no concluyente, evaluando los signos de lesión de SLAP en RM dinámica (RMD) y ArtroRM dinámica (ARMD). Material y método: se realizó un estudio prospectivo evaluando mediante RMD y ARMD a 10 pacientes con inestabilidad articular y RM convencional previa no concluyente. Se analizaron los signos positivos para lesiones del complejo bicípito labral (CBL), las lesiones asociadas del manguito rotador y complejo labro ligamentario; y los falsos positivos y negativos. Evaluamos las variantes de la lesión acorde a la clasificación artroscópica de Snyder (tipo I herida labral pura, tipo II avulsión del CBL, tipo III herida en asa de balde que respeta al tendón bicipital y tipo IV herida en asa de balde que se extiende dentro del tendón bicipital), aceptada en forma unánime en la práctica traumatológica nacional e internacional. Resultados: se descubrieron 8 casos con signos positivos para lesiones de tipo SLAP, 6 ARMD y 2 RMD. En 2/10 casos no se observaron lesiones SLAP. La totalidad presentaba alguna otra lesión tendinosa, labral u osteocartilaginosa asociada y diagnosticada previamente en la RM convencional. Conclusión: la RMD y la ARMD han demostrado ser de utilidad en la presentación de la lesión de SLAP y su clasificación, contribuyendo al diagnóstico completo y planeamiento quirúrgico apropiado