Biomechanical results of percutaneous calcaneal osteotomy using two different osteotomy designs

Percutaneous osteotomy of calcaneus has been proposed to reduce the complication rate and became more and more popular. The bone cut can be performed as a straight or chevron-like (V) osteotomy using a Shannon burr. Comparative studies of straight or V-osteotomy as like as one or two screws in percutaneous calcaneal osteotomies are missing in the literature. We hypothesize that the V-osteotomy will result in a higher stiffness in biomechanical testing as the straight osteotomy using single screw for fixation.

The straight osteotomy (9 fresh-frozen specimens) and V-osteotomy (9 fresh-frozen specimens) was performed and the calcaneal tuberosity was moved 10mm medially and slightly rotated. One 6,5mm cancellous compression screw was used for osteosynthesis. Specimens were preconditioned with 100N over 100 cycles. The force was increased after every 100N by 100N from 200 to 500N. This was followed by cyclic loading with 600N for 500 cycles.

Despite the higher mean values of the group with V-osteotomy, no significant difference was registered between the two groups regarding the stiffness at all force levels. A higher failure rate was observed in the group with straight osteotomy.

The moderate correlation of bone density and stiffness in the V-group, and significantly lower failure rate with no secondary dislocation in fluoroscopy indicates the superiority of the V-osteotomy in the present study. Whether the demonstrated advantages can be reflected in clinical practice should be investigated in further studies.

5.