85 SPECT/CT in the post-operative painful knee Figure 7 SPECT/CT after right-sided tibial osteotomy revealing increased BTO at the dorsal side of the wedge osteotomy where new callus is being formed (arrow). Normal BTO in the rest of the osteotomy and around the screw, consistent with uncomplicated healing. Slightly increased BTO in the medial knee compartment on the right (arrowhead), indicative of mild medial OA. (A) Planar late phase, (B) CT, (C) sagittal SPECT, and (D) fused sagittal SPECT/ CT. SPECT image courtesy of Prof. Dr K. Strobel (Lucerne, Switzerland). Additionally, bone-SPECT/CT arthrography can be used to depict the cartilage which is relevant after corrective osteotomy, as changed biomechanical forces on the knee joint will affect weight bearing in the knee cartilage and thus may induce pathology [41]. Another, less frequently used knee joint preserving method is a knee spring system (KSS) in patients with medial OA of the knee (Figure 8). 3