Abstract
Introduction
Single photon emission computed tomography (SPECT) can be used to create a three dimensional image of a radiopharmaceutical bone scan. This combined with high resolution CT scan (SPECT-CT) with bone windows allows the linking of the information obtained in both investigations. The multiplanar anatomical information provided by CT is therefore linked with the functional, biological information of bone scintigraphy. The painful total ankle replacement has a number of potential causes of discomfort including impingement and loose components. Correct identification of the source of pain will assist surgeons in treating the source of the pain while avoiding unnecessary surgery. We present our experience of the use of SPECT-CT to investigate patients with ongoing pain following Total Ankle Replacement (TAR).
Materials and Methods
A retrospective analysis of all patients having SPECT-CT for continuing pain following TAR. Scans were requested in addition to plain radiographs, joint aspiration and blood testing. Results: A total of 12 patients were identified. The scan proved helpful in all cases. 5 patients showed increased uptake around one or both prostheses signifying loosening which was not apparent on plain films. Gutter impingement was identified in 4 patients. One patient had a talo-navicular non-union, one patient demonstrated sub-talar joint arthrosis and one patient showed no bony abnormality but soft tissue impingement at arthroscopy.
Discussion
SPECT-CT provides a useful adjunctive investigation in the work-up of the patient with ongoing pain in a TAR, particularly in the cases of component loosening where plain x-rays may be limited. The SPECT-CT assists in the correct anatomical localization of the pain and has assisted in identifying the correct surgical treatment. Disadvantages include cost and availability of scanners.
