Nuclear Medicine for the Orthopedic Foot and Ankle Surgeon

Abstract

Nuclear medicine has been widely applied as a diagnostic tool for orthopedic foot and ankle pathology. Although its indications have diminished with improvements in and the availability of magnetic resonance imaging, nuclear medicine still has a significant and valuable role. The present article offers a comprehensive and current review of the most common nuclear imaging modalities for the orthopedic foot and ankle surgeon. Methods discussed include bone scintigraphy, gallium citrate scintigraphy, labeled-leukocyte scintigraphy, and single-photon emission computed tomography (SPECT). We review the indications and utility of these techniques as they pertain to specific foot and ankle conditions, including osteomyelitis, stress fractures, talar osteochondral lesions, complex regional pain syndrome, oncology, plantar fasciitis, and the painful total ankle arthroplasty. We conclude with a discussion of our approach to nuclear medicine with illustrative cases. Level of Evidence: Level V, expert opinion.

Pathogenesis, Evaluation, and Management of Osteolysis Following Total Ankle Arthroplasty

“…Up to 98% of patients may demonstrate osteolysis on radiographs, and this finding may even be expected due to stress shielding with some implants. 27,84 Furthermore, osteolysis often occurs within the cancellous bone of the distal tibia and proximal talus, and because of the thick cortical bone surrounding this area, a large degree of calcium can be lost before it becomes apparent on plain radiographs. Additionally, the metallic components of the implant can obscure visualization of osteolysis at the bone-implant interface.…”

“…These imaging modalities can identify areas of increased physiologic activity in the bone surrounding the prosthesis that can indicate suspicion for implant loosening. 84 Bone scintigraphy has been shown to be highly nonspecific in the hip arthroplasty literature, with variable false-positive and false-negative rates of detecting periprosthetic osteolysis and loosening (Figure 2). 18 Initial studies, however, have found SPECT/CT to be useful in evaluating suspected loosening of TAA prostheses, and to differentiate aseptic loosening from other sources of pain following TAA.…”

Evaluating and Managing the Painful Total Ankle Replacement

“…51 Up to 98% of patients may show some degree of osteolysis on postoperative radiographs. 23,94 Even in asymptomatic patients, periodic radiographic surveillance should be performed postoperatively so that any clinically silent cystic lesions can be detected early. It is crucial to monitor cysts radiographically for progression, as large, progressive cysts can increase the risk of fracture and the need for revision surgery.…”

“…68 SPECT may also be used and can identify areas of increased physiologic activity at the bone-implant interface, which may represent loosening or cyst formation. 39,70,94 Metal artifact reduction MRI is also useful and can identify significantly more osteolysis and edema in painful TAR compared to traditional MRI techniques. 17 Multiple factors have been identified as potential etiologies for the development of cysts and osteolysis.…”

The Role of Bone Scintigraphy with SPECT/CT in the Characterization and Early Diagnosis of Stage 0 Charcot Neuroarthropathy

“…The previous use of three-phase bone scintigraphy in diabetes patients with neuropathy suggested increased blood flow to bone but the planar imaging has low anatomical resolution [9]. However, the introduction of hybrid Single Photon Emission Computed Tomography/ Computed Tomography (SPECT/CT) in nuclear medicine has improved the diagnostic potential of bone scintigraphy [10]. Combining SPECT and CT considerably increases bone scan image quality (attenuation correction), anatomic localization and diagnostic accuracy [11].…”