A guide instrument for high tibial osteotomy.

Fifty-two patients (52 knees) with medial gonarthrosis were subjected to high tibial osteotomy using the Tjörnstrand guide instrument. The intended wedge was calculated from a whole lower limb radiograph. The correction aimed at was an overcorrection of 4 degrees in valgus of the hip-knee-ankle angle. All but 1 case were corrected to +/- 3 degrees of the intended angle. All but two cases healed within +/- 3 degrees of the achieved surgical correction, i.e., a substantial improvement compared with our previous freehand technique where one fifth were outside this interval. We conclude that in knee surgery a guide is as important for osteotomies as for arthroplasties.