Association of Extraosseous Arterial Diameter With Talar Dome Osteochondral Lesions.

Background: Etiology of osteochondral lesions of the talus (OLT) is multifactorial and may develop from trauma, genetics, or hypovascularity. The talar dome is supplied by the posterior tibial artery (PTA) and, to a lesser degree, the sinus tarsi artery (STA). The role of talar dome hypovascularity on OLT remains poorly studied. We aimed to determine any relationship between the diameter of PTA (dPTA) and STA (dSTA) and the incidence and characteristics of talus OLT.

Methods: This retrospective study included 77 patients with OLT and 77 subjects as a matched control group (age range: 30-40 years). Using magnetic resonance imaging, the dPTA was measured 1 cm above the tibial plafond, at the plafond, and at the level of medial malleolar tip. Likewise, dSTA was measured at the level of the talar neck. The area, volume, depth, localization, and surgical intervention for OLT were recorded as well.

Results: The study group had significantly smaller dPTA at all 3 levels (1.05 ± 0.22 mm, 0.99 ± 0.18 mm, 0.98 ± 0.31 mm, proximal to distal, respectively) compared with controls (1.25 ± 0.23 mm, 1.20 ± 0.22 mm, 1.14 ± 0.18 mm, respectively) (P < .001). The dSTA was also significantly smaller in the study group compared with the control group (0.5 ± 0.11 mm vs 0.57 ± 0.08 mm, respectively; P = .001). The mean dPTA (of all 3 levels) cutoff value for predicting the occurrence of OLT was 1.1 mm with 74% sensitivity and 75% specificity. A significant inverse correlation was observed between OLT area and arterial diameters (P < .001).

Conclusion: Smaller luminal dPTA and dSTA appear to be associated with higher incidence of OLT, with defect size inversely correlated to arterial diameter.