Carol J. Ashman

The plantar fasciotomy: MR imaging findings in asymptomatic volunteers

Abstract Objective. To determine the postoperative appearance of the plantar fascia on MR imaging after a fasciotomy has been performed, and to compare the postsurgical appearance of the fascia after an open and endoscopic procedure.<@head-abs-p1.lf>Design and patients. Fifteen asymptomatic volunteers (12 women, 3 men; age range 22–49 years, mean age 33 years) with prior fasciotomies for treatment of longstanding plantar fasciitis were studied. Fourteen volunteers had a unilateral release and one volunteer had bilateral releases, allowing for assessment of 16 ankles. Eight fasciotomies were performed through an open incision and eight were performed endoscopically. The average time between surgery and imaging was 24 months (range 11–46 months). The site of surgery was established from the operative reports. Proton density (PD)-weighted and T2-weighted images in three orthogonal planes were obtained on a 1.5-T magnet. In eight studies, T1-weighted sagittal and STIR sagittal images were included. The fascia in each ankle was assessed for morphology and signal intensity. Perifascial soft tissues and bone marrow were assessed for edema. Preoperative MR studies were available in five volunteers.<@head-abs-p1.lf>Results. There was no apparent difference in the postoperative appearance of the ankle after an open or endoscopic procedure except for scar formation in the subcutaneous fat which was common after an open procedure (P<0.05). Three ankles had a gap in the fascia (one open, two endoscopic). The plantar fascia measured a mean of 7.0 mm (range 5–10 mm) at the fasciotomy, and 8.3 mm (range 6–12 mm) at the enthesis. At the fasciotomy, 11 of 13 ankles had an indistinct deep contour and 9 of 13 had an indistinct superficial contour. At the enthesis, 13 of 16 ankles had an indistinct deep contour and 6 of 16 had an indistinct superficial contour. Compared with preoperative MR studies there was an average reduction in the fascial thickness at the enthesis of 14% (range 9–20%), but the thickness at the fasciotomy nearly doubled. No edema was evident in the fascia, perifascial tissues, deep plantar muscles, or calcaneal bone marrow.<@head-abs-p1.lf>Conclusions. The average thickness of the plantar fascia in asymptomatic volunteers after surgery is nearly 2–3 times that of normal. While there is increased thickness at the site of surgery, the changes in morphology and signal intensity were most prominent at the enthesis. The key observation was absence of edema in the fascia and perifascial soft tissues. This baseline information may be of value when assessing MR studies of symptomatic patients.

MR patterns of involvement of humeral head osteonecrosis.

Purpose To characterize osteonecrosis of the humeral head on coronal and axial MR images. Methods We retrospectively reviewed MR examinations in patients with humeral head osteonecrosis. The angle of the entire affected articular surface at three levels was measured and an angle subtended by the margins of osteonecrosis was also measured. Results The appearance of osteonecrosis is identical to that in the femoral head with signal abnormality (13/13), double-line sign (7/13), and subchondral fractures (3/13). The superior aspect of the humeral head was the most common location of osteonecrosis. The MR staging resulted as follows: stage II (6/13), stage IIIA (1/13), stage IIIB (1/13), and stage IV (5/13). The maximum percentage of involvement of the articular surface demonstrated the following distribution: 0% to 25%, 0/11; 25% to 50%, 1/13; 50% to 75%, 5/13; and 75% to 100%, 7/13. Conclusions Quantitative analysis of the percentage of involvement of the humeral head was performed and indicates that in most cases, 75% to 100% of the articular surface at the levels measured was involved.

A Problem of Mistaken Identity: Mimics of Musculoskeletal Neoplasms

Many processes may appear similar to osseous and soft tissue neoplasms on imaging studies. Traumatic, infectious, articular, metabolic, vascular, and dysplastic disorders, developmental lesions, and anatomic variants may demonstrate characteristics that can cause them to be misconstrued as tumors. E

The chance fracture: Anteroposterior radiographic signs

Chance fractures and their ligamentous equivalents may be readily diagnosed on lateral radiographs of the thoracolumbar spine, but often, the lateral view is of insufficient diagnostic quality in the emergency setting. It is imperative, therefore, to recognize the findings of Chance injuries on the anteroposterior view of the spine. This pictorial essay emphasizes the various manifestations of the Chance fracture on the anteroposterior radiograph, an understanding of which is facilitated by a review of the mechanism of this injury.