Abstract
Surgical Principles In varus osteoarthritis of the knee the force of weight bearing, which normally passes through the centre of the weight bearing surfaces, is medially displaced [4, 8]. In order to redistribute the load evenly over a larger articular surface a modified Maquet upper tibial osteotomy via midline vertical incision is performed. By valgus overcorrection of 5°, the tibial plateau is tilted and this changes the mechanical axis in such a way, that the resultant forces pass through the centre of the knee joint and at a right angle to the plane tangential to the articular surfaces [7, 9]. The degree of correction (varus deformity + 5°) is determined preoperatively on the basis of a full length, single stance weight bearing film (120 cm × 30 cm, distance at least 3 m) [8]. The fibula is divided to allow adequate correction of the tibia; this is done by excising a segment of the fibula. Because of variations in the innervation of the extensor hallucis longus muscle this should be performed in a relatively safe area, about 160 mm distal to the fibular head [5] through a postero-lateral approach [4]. The size of the excised segment depends on the degree of correction required. A dome osteotomy (barrel vault osteotomy) above the level of the tibial tubercle allows a correction of up to 25°. The osteotomy is compressed with at least four staples in two different planes. Contrary to the technique described by Maquet [8] the distal tibial fragment is not advanced anteriorly.
Published Version
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