The utility of the ankle SPECT/CT scan to predict functional and clinical outcomes in supramalleolar osteotomy patients

Combined single‐photon emission computed tomography and conventional computed tomography (SPECT/CT) is a hybrid imaging modality that shows a combination of metabolic and structural information about the ankle, including arthritis. We hypothesize that uptake in specific locations within the ankle joint can be associated with both clinical outcomes and may help predict which patients will have a successful SMO. Eighty‐five pre‐operative SMO patients with varus (37), valgus (41), or neutral (7) alignment of the hindfoot were assessed using SPECT/CT. The level of activation on SPECT/CT scans was measured. Pre and Post‐operative functional scores were recorded. Patients with medial gutter activation had significantly worse (p < 0.05) AOFAS alignment (AOFAS‐A) scores pre‐operatively. Patients with varus or valgus alignment did not have any difference in VAS pain scores, but those in valgus did have worse AOFAS‐P (pain) scores. Those with cystic lesions had a worse FAOS score pre‐operatively. Ten patients (12.5%) had a treatment failure. Pre or post‐operative alignment did not correlate to a treatment failure. The only statistically significant (p = 0.036) poor prognostic indicator was a bipolar lesion. Pre‐operative SPECT/CT evaluation of an ankle before a SMO can be used to clinically correlate patient‐specific factors such as pain and function in the pre and post‐operative period. We caution against performing a SMO in patients with bipolar activation on a pre‐operative SPECT‐CT scan.