MEDLINE Abstracts: The Use of Imaging in Talar Fractures
What's new concerning the imaging of talar fractures? Find out in this easy-to-navigate collection of recent MEDLINE abstracts compiled by the editors at Medscape Orthopaedics & Sports Medicine.









Haraguchi N, Kato F, Hayashi H
Journal of Bone & Joint Surgery - British Volume 80(4):684-8, 1998 Jul

We report two new radiographic projections for evaluating avulsion fractures at the lateral malleolus. We used seven freshly amputated legs with simulated avulsion fractures and radiopaque markers to assess their value. The projections allow accurate assessment of the displacement of fragments without superimposition, and also show whether they affect the anterior talofibular or the calcaneofibular ligament or both.









Bahk YW, Chung SK, Park YH, Kim SH, Lee HK
Journal of Nuclear Medicine 39(1):130-9, 1998 Jan

Pinhole SPECT can generate sectional nuclear images of a normal and morbid ankle and hindfoot with remarkably enhanced resolution by portraying the topography and pathological alterations in great detail.
Methods: Pinhole SPECT was performed using a commercially available single-head, rotating gamma camera system by replacing the parallel-hole collimator used for planar SPECT with a pinhole collimator. The images were reconstructed in the same way as in planar SPECT by using the filtered back-projection algorithm and a Butterworth filter. First, we compared the scan resolution between the planar and pinhole SPECT images of a thyroid phantom and a normal ankle and hindfoot by working out pinhole SPECT anatomy with CT validation. Second, the clinical usefulness was assessed in one case each of fracture, reflex sympathetic dystrophy syndrome and rheumatoid arthritis of the ankle with radiographic correlation. The resolution of the pinhole SPECT and planar pinhole images was compared for these diseases.
Results: The resolution of the pinhole SPECT of a thyroid phantom and of a normal ankle and hindfoot was significantly enhanced compared to the planar SPECT although image distortion was seen in the periphery of the field-of-view. The pinhole SPECT resolution was such that most of the anatomical landmarks were sharply delineated in the ankle and hindfoot and some useful diagnostic signs in the diseased ankle were visible.
Conclusion: Pinhole SPECT can be performed using a single-head gamma camera system and filtered back-projection algorithm. It generates sectional scan images of both normal and morbid ankle and hindfoot with enhanced resolution portraying many anatomical landmarks and pathological signs in useful detail.









Brage ME, Bennett CR, Whitehurst JB, Getty PJ, Toledano A
Foot & Ankle International 18(6):324-9, 1997 Jun

We analyzed 50 sets of ankle radiographs to determine the interobserver and intraobserver reliability when obtaining common linear and angular measurements. The radiographs were divided into two groups: one group included 25 normal ankles, and the second group included 25 fractured ankles. Each set of radiographs was evaluated independently by four different observers on two separate occasions under controlled conditions. Six radiographic parameters were measured on all 50 sets of films: syndesmosis A, syndesmosis B, syndesmosis C, the medial clear space, and the talocrural and bimalleolar angles. On the 25 sets of fracture films, four additional measurements of fracture displacement were included: displacement of the medial malleolus (mortise), displacement of the lateral malleolus (AP and lateral), and displacement of the posterior malleolus. Reliability was evaluated with an analysis of variance intraclass correlation coefficient. Among the examiners, 9 of the 10 parameters could be measured reliably. Intraobserver reliability was found to increase with the experience of the examiner.









Wechsler RJ, Schweitzer ME, Karasick D, Deely DM, Glaser JB
Skeletal Radiology 26(3):137-42, 1997 Mar

Since the degree of comminution, fracture alignment, and articular congruity of talar fractures are important determinants of treatment, we review the helical CT technique for detecting and assessing the extent of acute talar fractures. Helical CT can be used to classify talar neck fractures which often cannot be determined by radiography. It is also useful in detecting posterior process, lateral process, and avulsion fractures, as well as acute osteochondral fractures. Multiplanar CT using 1-mm acquisitions allows optimal evaluation, detects fractures initially missed on radiographs, and determines further extent of fractures.









Prokuski LJ, Saltzman CL
Radiologic Clinics of North America 35(3):655-70, 1997 May

The foot and ankle is one of the most imaged parts of the body. Although most plain radiographs reveal no bony injury, subtle fractures can be overlooked. Because it is important to detect these fractures at the time of injury, a review of the most commonly missed foot and ankle fractures is presented.









Thordarson DB, Triffon MJ, Terk MR
Foot & Ankle International 17(12):742-7, 1996 Dec

Twenty-one consecutive patients with displaced talar neck fractures (12 Hawkins type II, 9 Hawkins type III) were prospectively evaluated with magnetic resonance (MR) scans performed between 3 days and 12 months after surgery. All patients underwent open reduction and internal fixation with titanium screws, except two who underwent fixation with stainless steel implants that were subsequently removed. All patients had plain radiographs. We classified the scans as follows: type A, no abnormal signal changes in the body of the talus; type B, signal changes in less than 25% of the body; type C, signal changes in 25% to 50% of the body; and type D, signal changes in greater than 50% of the body. Plain anteroposterior radiographs correlated well with MR scans in patients with type D scans, but an inconsistent correlation was noted with lesser degrees of signal changes (types A-C), with the MR scans being more accurate in displaying the volume of avascular bone. Scans obtained less than 3 weeks after injury were not helpful in assessing for avascular necrosis. We found that high-quality MR images of the talus were consistently obtained in the presence of titanium screws in contrast to images obtained with stainless steel implants. We use titanium screws in all talar neck fracture repairs, because they permit high-quality MR images. We believe that further study of patients with Hawkins type III fractures and Hawkins type II fractures with equivocal radiographic evidence of avascular necrosis is warranted to try to identify those patients at risk for collapse and perhaps to guide weightbearing recommendations.









Bohay DR, Manoli A II
Foot & Ankle International 17(3):164-9, 1996 Mar

Subtalar joint dislocations, although not common, have been increasing in frequency over the last decade. Generally, subtalar joint dislocation can be treated successfully with closed reduction and a short period of cast immobilization. The majority of patients will suffer minimal disability, with subtalar joint stiffness as the primary complaint. This report includes four cases of suspected joint dislocation or subluxation with occult intra-articular fractures identified only by CT scan following essentially normal radiographs. Evidence seems to indicate that CT scanning in patients with suspected subtalar joint subluxation or dislocation and normal radiographs is justified.









Whitby EH, Barrington NA
British Journal of Radiology 68(810):583-6, 1995 Jun

We present three cases of fractures of the lateral process of the talus, where routine anteroposterior and lateral radiographs showed an abnormality but were insufficient to assess the degree of bony injury, which is important for clinical management. Lateral tomography provided good diagnostic and anatomical detail. The diagnosis and treatment of this unusual and often missed fracture is discussed.