METHOD FOR PREOPERATIVE PLANNING OF CORRECTIVE OSTEOTOMY OF SHIN BONES FOR BOWED LEGS CORRECTION Russian patent published in 2015 - IPC A61B6/00 A61B17/56 

FIELD: medicine.

SUBSTANCE: method involves recording a teleroentgenogram of both legs, including hip and ankle joints of a patient standing so that his/her legs touching each other at the level of medial malleoli; lower legs are contoured on the teleroentgenogram. A line passing through the centre of pubic symphysis and the most projecting point of an inner contour of the shin bone at the level of an inner shin-bone (SB) ankle is marked to divide the roentgenogram in two. Each of them is turned about the centre of femoral (F) head until the most projecting point of the inner contour of femur is placed on a line perpendicular to a bispinal line. That is followed by separating three complexes, wherein the complex I comprises the outer and inner contours of the extremity above the level of expected osteotomy, femoral skiagram and a proximal fragment of the SB. The complex II includes the inner contour of the shin bone below the osteotomy level and skiagram of a distal fragment of the SB. The complex III comprises the outer contour of the shin bone and fibular bone (FB) skiagram. valgisation and medialisation of the distal fragments of the SB and FB bringing down are simulated in stages. When simulating the valgisation, the complexes II and III are turned about an intersection point of an outer cortical layer of the SB and a line of the expected osteotomy until the most projecting point of the inner contour of the shin bone on the line perpendicular to the bispinal line. An angle, which both complexes are turned at is equal to a value of the expected valgisation. When simulating the medialisation of the distal fragments of the SB, the complex II is rotated about a point matched to the most distal point of the distal tibiofibular syndesmosis before the most projecting point of the inner contour of the shin bone is placed on a line perpendicular to the bispinal line. A distance between the intersection point of the inner contour of the shin bone with a mechanical axis of the SB before and after rotation of the complex II is equal to a value of the expected medialisation. When simulating FB bringing down, the complexes II и III are moved downwards at a value of the expected distraction. The complex III is rotated about the most distal point of the distal tibiofibular syndesmosis until the most proximal point of the proximal tibiofibular joint is placed on the outer cortical layer of the SB.

EFFECT: accurate planning of the required value of valgisation, varisation or medialisation of bone fragments to provide an ideal leg shape, planning the required value of bringing the fibular bone down to preserve the shin bone width; ensuring the pre-operative assessment of the impact of various surgical options on the biomechanical properties of the lower extremity.

22 dwg, 1 tbl, 1 ex