Bone SPECT/CT in the Evaluation of Painful Total Ankle Replacement: Validation of Localization Scheme and Preliminary Evaluation of Diagnostic Patterns

Managing Intraoperative Fractures During Total Ankle Replacement

Intraoperative complications during total ankle replacement (TAR) can be devastating. As surgeons' experience with total ankles grow and surgical techniques are refined, intraoperative complications, such as fractures, can still occur. Surgeons must be able to recognize a problem, identify the options to remediate, and then execute a solution readily. Unfortunately, given the heterogeneity of TAR outcome studies, it is difficult to garner the true incidence of complications in the peri-operative period following ankle replacements. The purpose of this review is to focus on perioperative fractures during TAR. Fractures can occur intraoperatively and postoperatively as stress fractures or post-operative trauma.

SPECT/CT of Total Ankle Arthroplasty

Use of SPECT/CT (Single Photon Emission Computed Tomography/Computed Tomography) is increasing providing additional information in patients with inconclusive clinical examination and unremarkable imaging findings presenting with chronic pain after total ankle arthroplasty. To differentiate the cause of pain after total ankle arthroplasty can be challenging. SPECT/CT combines structural and metabolic imaging as a hybrid tool leading to higher specificity and overall diagnostic accuracy presumably in cases of gutter impingement, prosthetic loosening, and osteoarthritis of adjacent joints. Moreover, SPECT/CT can complement diagnostic work up in periprosthetic joint infections. Basal tracer enhancement has to be considered for the interpretation of imaging findings.

Magnetic Resonance Imaging of Total Ankle Arthroplasty: State-of-The-Art Assessment of Implant-Related Pain and Dysfunction

Total ankle arthroplasty (TAA) is an effective alternative for treating patients with end-stage ankle degeneration, improving mobility, and providing pain relief. Implant survivorship is constantly improving; however, complications occur. Many causes of pain and dysfunction after total ankle arthroplasty can be diagnosed accurately with clinical examination, laboratory, radiography, and computer tomography. However, when there are no or inconclusive imaging findings, magnetic resonance imaging (MRI) is highly accurate in identifying and characterizing bone resorption, osteolysis, infection, osseous stress reactions, nondisplaced fractures, polyethylene damage, nerve injuries and neuropathies, as well as tendon and ligament tears. Multiple vendors offer effective, clinically available MRI techniques for metal artifact reduction MRI of total ankle arthroplasty. This article reviews the MRI appearances of common TAA implant systems, clinically available techniques and protocols for metal artifact reduction MRI of TAA implants, and the MRI appearances of a broad spectrum of TAA-related complications.

[Radiological-nuclear medicine hybrid diagnostics with SPECT/CT for chronic foot and ankle diseases : A new and important diagnostic tool]

BACKGROUND AND AIM

In contrast to standard methods (sonography, X‑ray, CT (computed tomography), MRI (magnetic resonance imaging), numerous diseases of the foot or ankle can be diagnosed using SPECT/CT (single photon emission computed tomography/computed tomography) with regard to their clinical relevance with high accuracy (up to > 90%). The aim of this review is to provide an up-to-date overview of the importance of SPECT/CT in selected diseases of the foot and ankle.

MATERIAL AND METHODS

A literature search was carried out in the Pubmed database using the following terms: SPECT/CT, SPECT, skeletal scintigraphy, CT, computed tomography, foot and ankle disease, OSG, tarsal root, foot pain. The publications were selected with regard to questions and diagnoses that frequently occur in foot and ankle diagnostics. Furthermore, papers that describe a more precise diagnosis, a change in therapy management or a reduction in symptoms due to the use of SPECT/CT were selected.

RESULTS

Several studies have shown that a focally increased bone metabolism in osteoarthritis and osteochondral lesions correlates significantly with the development of pain. The presence of symptomatic ossicles such as the os naviculare accessorium type II and os trigonum can be clearly demonstrated with the help of SPECT/CT and cannot be assigned as the source of the symptoms as accurately with any other imaging method. Bony reactions in the area of coalitions, arthrodesis, osteosynthesis, occult fractures, prostheses and diabetic foot cannot be detected with comparable accuracy using any other imaging method, so that therapy concepts in unclear cases, based only on standard imaging are changed in up to 2/3 of cases by SPECT/CT information.

DISCUSSION AND CONCLUSION

SPECT/CT is useful when there are clinical uncertainties despite standard imaging.