Biomechanical Effect of Distal Tibial Oblique Osteotomy: A Preliminary Finite-Element Analysis

The biomechanical effect of distal tibial oblique osteotomy (DTOO) on osteoarthritic ankles has not been investigated. Using finite element (FE) models, we aimed to elucidate the effect of DTOO on the ankle contact pressure (CP) distribution.

This study included two patients with ankle osteoarthritis who underwent DTOO and one asymptomatic control. Patient-specific FE models were reconstructed by matching standing radiographs with supine computed tomography scans. The joint contact area (CA) and maximum CP on the articular surface of the talus were calculated before and after DTOO and compared with those of the control.

In the control, the CA was 584 mm² and the maximum CP was 2.6 MPa. In case 1, the CA increased by 125% from 166 mm² preoperatively to 375 mm² postoperatively, accompanied by a 36% decrease in the maximum CP from 9.8 MPa to 6.3 MPa. Similarly, in case 2, the CA increased by 46% from 301 mm² to 439 mm², accompanied by a 27% decrease in the maximum CP from 6.7 MPa to 4.9 MPa.

This study suggests DTOO improves the biomechanics of the ankle, but not sufficiently compared to the control. This analytical approach may enhance understanding of ankle pathophysiology and assist in the design of the ideal corrective osteotomy.