Bone tracer uptake in SPECT/CT is a potential indicator for treatment decision-making in cystic osteochondral lesions of the talus

Aims Cystic osteochondral lesions of the talus (OLTs) demonstrate metabolic dysregulation that predisposes to osteonecrosis, for which timely invasive intervention is crucial. This study aimed to investigate the predictive value of bone tracer uptake (BTU) of single-photon emission CT/CT (SPECT/CT) for conservative treatment outcomes, and promote a novel indicator for decision-making of the treatment of cystic OLTs. Methods Patients with cystic OLTs who underwent SPECT/CT scanning from January 2020 to August 2024 received three-month conservative treatments. Maximum standardized uptake value (SUV max ) was quantified from SPECT/CT acquisitions. Visual analogue scales (VAS) for pain and American Orthopaedic Foot and Ankle Society (AOFAS) scores were assessed before and after the treatment. A total of 95 patients were divided into the Success (23) and Failure (72) groups based on post-treatment AOFAS scores (80). VAS, AOFAS, and SUV max were compared, and receiver operating characteristic (ROC) curve analysis was performed. Results The Failure group had significantly higher mean SUV max (12.35 (SD 4.94) vs 6.45 (SD 4.63), p < 0.001) and inferior mean AOFAS scores (75.03 (SD 8.97) vs 80.35 (SD 10.29), p = 0.033). Maximum BTU located predominantly on sclerotic bone rims of OLTs (90/95, 94.7%). Medial OLT had significantly greater mean SUV max (11.77 (SD 5.45) vs 7.06 (SD 3.68), p < 0.001). When the SUV max exceeded 8.62 (sensitivity 81.9%, specificity 82.6%), OLT patients were more likely to fail the conservative treatment. Conclusion This study demonstrates that SPECT/CT-derived BTU is a potential indicator for treatment decision-making in cystic OLTs. Elevated BTU showed a statistically significant association with poor response to nonoperative care in this cohort. The critical threshold of SUV max > 8.62 (sensitivity 81.9%, specificity 82.6%) identifies high-risk patients who might need early surgical intervention. Additionally, the SUV max showed a strong correlation with ankle pain, and maximum BTU located predominantly on the sclerotic rims of OLTs. Cite this article: Bone Joint Res 2026;15(7):784–794.