Avascular necrosis of the talus

Avascular necrosis of the talus: current treatment options

AVN of the talus is a challenging disease process with respect to patho-physiology and treatment. We believe that our algorithm is a legitimate approach to aid the orthopedic surgeon in initiating a promising treatment. It is divided into different levels and allows to change between some. This is not the only way to proceed but it seems promising, especially if the long-term results with the vascularized bone grafts show revascularization of the talus. As always in medicine, the treatment needs to be individualized. Arthrodesis always should be the last option and is a challenging procedure.

Avascular necrosis of bone in severe acute respiratory syndrome

AIM: To report the incidence of avascular osteonecrosis (AVN) in severe acute respiratory syndrome (SARS) patients.

MATERIALS AND METHODS: Sixty-seven SARS patients who had large joint pain between March 2003 and May 2003 underwent both plain radiographs and magnetic resonance imaging (MRI) examination on the same day. All patients received steroids and ribavirin treatment. All plain radiographs and MR images were analysed by two experienced musculoskeletal radiologists. Any abnormalities, location, extent, morphology, the number, size and signal intensity of lesions were evaluated.

RESULTS: Twenty-eight patients were identified with AVN, The mean time to diagnosis of AVN was 119 days after the onset of SARS, or 116 days after steroid use. Three patients had early bilateral AVN of the femoral head, four patients of one femoral head, five patients of the bilateral hips and knees, four patients of the ipsilateral hip and knees, 10 patients of the knee(s), one patient of the right proximal fibula, and one patient of the knees and talus. Results of hip, knee and ankle plain radiographs were negative.

CONCLUSION: AVN can occur in the patients with SARS. AVN had a strong association with steroid use. More studies are required to confirm whether the virus itself can also lead to AVN.

Avascular necrosis of the talus

Avascular necrosis (AVN) of the talus has always been a surgical challenge because the talus is hidden by its anatomic location and has a precarious blood supply. Most cases (75%) of talar AVN are traumatically induced in association with talar body and talar neck fractures.AVN of the talus can be a significant problem because collapse of the talar dome leads to degenerative changes and pain and disability of the ankle and subtalar joints. Although there are many published treatments for posttraumatic AVN of the talus, critical outcome studies are still lacking.

Avascular necrosis of the talus

Persistent pain in the ankle after relatively minor trauma is common and usually resolves spontaneously. Two cases of persistent pain after minor trauma are presented that involved unusual characteristics of scintigraphic and magnetic resonance imaging, compatible with avascular necrosis of the talar body. This is a rare finding in the absence of steroid use or significant trauma to the foot. The unusual vascular anatomy of the talus is considered in the possible mechanism of injury.

Talar neck fractures and rates of avascular necrosis

Talar neck fractures are unique and potentially debilitating injuries. Their successful treatment requires an understanding of talar anatomy and arterial blood supply, as well as knowledge of the sequelae of these injuries, particularly avascular necrosis of the talar body. Presented is an extensive literature review on talar neck fractures and Hawkins' classification, with special emphasis on the rates of avascular necrosis as determined by selected researchers on the topic.

Magnetic resonance imaging to detect avascular necrosis after open reduction and internal fixation of talar neck fractures

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.