Increased Osseous (99m)Tc-DPD Uptake in End-Stage Ankle Osteoarthritis: Correlation Between SPECT-CT Imaging and Histologic Findings

• Published in: Foot & ankle international 2015-12, Vol.36 (12), p.1438-1447
• Main Authors: Paul, Jochen, Barg, Alexej, Kretzschmar, Martin, Pagenstert, Geert, Studler, Ueli, Hügle, Thomas, Wegner, Nicholas J, Valderrabano, Victor, Geurts, Jeroen
• Format: Article
• Language: English
• Subjects: Aged; Ankle Joint - diagnostic imaging; Ankle Joint - pathology; Ankle Joint - surgery; Arthroplasty, Replacement, Ankle; Bone Marrow - diagnostic imaging; Bone Marrow - pathology; Bone Remodeling; Cartilage, Articular - diagnostic imaging; Cartilage, Articular - pathology; Cell Count; Collagen; Diphosphonates; Female; Humans; Male; Middle Aged; Multimodal Imaging; Organotechnetium Compounds; Osteoarthritis - diagnostic imaging; Osteoarthritis - pathology; Osteoarthritis - surgery; Osteoblasts - diagnostic imaging; Osteoblasts - pathology; Radiopharmaceuticals; Talus - diagnostic imaging; Talus - pathology; Tibia - diagnostic imaging; Tibia - pathology; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed
• ISSN: 1944-7876
• DOI: 10.1177/1071100715596745

We analyzed the histopathologic findings in end-stage osteoarthritic ankle joint tissue that display increased uptake of bone-seeking radiotracer in single-photon emission computed tomography-computed tomography (SPECT-CT) imaging. Six consecutive patients with end-stage osteoarthritis undergoing total ankle replacement received preoperative SPECT-CT imaging using (99m)Technetium dicarboxypropane diphosphonate ((99m)Tc-DPD). Using imaging data for stratification, osteochondral tissue sections were prepared from SPECT-positive (+) and -negative (-) areas of tibial and talar resection specimens. Histomorphometric analyses of osteoblast numbers, collagen deposition, and cartilage degeneration were performed on hematoxylin and eosin, van Gieson's and Safranin-O stained tissue sections. Osteoclast activity was visualized using tartrate-resistant acid phosphatase (TRAP) staining. Increased (99m)Tc-DPD uptake was observed exclusively subjacent to the subchondral bone plate of tibial and talar joint compartments. SPECT(-) tissues displayed typical fatty marrow morphology containing mainly collagen-positive blood vessels and few marrow and bone-lining cells. SPECT(+) tissues were characterized by increased numbers of active bone-lining osteoblasts depositing collagen fibers. Collagen area fraction of subchondral bone marrow was significantly increased in SPECT(+) (0.52 ± 0.21) compared with SPECT(-) (0.29 ± 0.13) tissues (P = .30). Multinucleated TRAP(+) osteoclasts were absent from bone formation sites, but associated with vascular structures invading articular cartilage through the subchondral bone plate. Increased (99m)Tc-DPD uptake was specifically and strongly correlated with increased osteoblast numbers (P = .011), and with collagen area fraction (P = .030) but not with Mankin score (P = .202), or with osteoclast number (P = .576). Subchondral bone tissues in SPECT(+) areas of end-stage ankle osteoarthritis were histologically characterized by increased osteoblast-mediated bone formation in the absence of functional osteoclasts, and increased cellularity and collagen deposition in marrow tissues. Our findings suggest a pathologic bone-remodeling process in end-stage ankle OA areas with increased (99m)Tc-DPD uptake.