Arthrex Open Wedge Osteotomy Technique Designed in conjunction with: Dr. Giancarlo Puddu, M.D. Dr. Peter Fowler, M.D. Dr. Ned Amendola, M.D. To treat pain and instability associated with lower extremity malalignment.
Advantages Single saw/osteotome cut Smaller incision Higher degree of precision Preserves bone stock Maintains normal anatomy Avoids peroneal nerve No tib/fib disruption Decreased/no risk of compartment syndrome Reduces incidents of malunion due to alteration of normal anatomy Bi-plane correction possible Maintains normal tibial slope May be performed with ACL reconstruction
Normal Weight Bearing Line The line of weightbearing, a line drawn from the femoral head to the center of the tibialtalor joint, in a normal patient.
Weight Bearing with Deformity The line of weight- bearing in this image is typical of a patient with a varus deformity. The correction needed is determined by using standing, full-length radiographs. Allowance is made for magnification.
Beginning Correction of Deformity First, a line is drawn from the femoral head to a point on lateral aspect of the tibia that is 62% of the width of tibial plateau. A second line is drawn from that point to the center of the tibial- talor joint.
Angle of Correction A second line is drawn from that point to the center of the tibial-talor joint. The angle created by the intersection of these two lines represents the angle of correction needed.
Amount of Correction Usually 1 degree of correction is made for every millimeter of opening of the osteotomy.
Inserting the Guidepin Under fluoroscopic control, a 3 MM guidepin is inserted from medial to lateral into the tibia beginning 1-2 cm below the joint line at a point central in the A-P plane and parallel to the tibial plateau. The pin is inserted to the lateral cortex.
Assembly of Guide The osteotomy guide is assembled by first placing the parallel guide pin sleeve assembly onto the post of the osteotomy guide.
AP Slope Guide The guide pin sleeves are then inserted though the holes of the parallel guide pin assembly. The angle of the guide is set so that the pins enter the tibia and pass through a point caphalad to the superior aspect of the tibial tubercle.
Placement onto Guide Pin The osteotomy guide is then placed onto the 3mm guide pin so that the rear of the guide is flush with the laser line etched on the guide pin.
Alignment of the Guide Alignment of the guide is such that placement of the two 2.4mm guide pins will be parallel to the tibial plateau.
Setting the Guide The parallel guide sleeve assembly can be rotated to make changes to the slope of the tibial plateau if desired. Normally the guide will be set to zero.
Positioning the Pin Sleeves The pin sleeves are positioned against the bone. The two 2.4 mm break-away pins are drilled to a depth that intersects the plane of the 3mm guide pin when viewed in the A-P plane with fluoroscopy.
Osteotomes The osteotomy is created along the plane created by these pins and a 1cm lateral, cortical bone hinge is created when osteotomes are driven to the same depth as the pins. The osteotomes have depth markings on the blades.
Cutting Guide The cutting guide is positioned over the distal pines. The guide may be secured by placing a temporary pin into the tibia with a mallet. The break- away pins may be shortened to facilitate access of the saw to the cutting guide.
Oscillating Saw An oscillating saw, positioned on the inferior surface of the cutting guide is used to resect the tibial cortex medially, anteriorly, and posteriorly. Once the maximum depth of the saw blade has been achieved, the cutting guide and guide pins are removed.
Osteotome Blades Osteotome blades, available in 10,25,and 35mm, are assembled on the handle and are used to complete the osteotomy. Fluoroscopic confirmation should be checked repeatedly throughout the cutting process.
Inserting the Osteotomy Wedge The osteotomy wedge is assembled, inserted into the osteotomy, and driven to the mark equal to the desired width of the plate selected. It is necessary to allow the bone to plastically deform while opening the osteotomy to prevent an inadvertent fracture into the tibial plateau or through the lateral cortex.
Placement of the Plate The handle is removed and the plate is placed between the tines of the osteotomy wedge.
Sizing the Opening When the desired opening had been achieved, alignment is verified externally from the hip to the ankle as well as by fluoroscopy to ensure the weight bearing line is through the lateral compartment. Adjustment to the opening may be accomplished by impacting or extracting the wedge to the next appropriate size.
Plate Fixation The plate is fixed with stainless steel 6.5mm cancellous screws proximally and 4.5 cortical screws distally. Bi or Tri-cortical wedges of autologous bone, harvested from the illiac crest, are used as grafts in the osteotomies greater than 7.5 mm. For defects 7.5mm and smaller, Local cancellous or no graft.
Completion of Procedure Following plate fixation and bone graft placement, the wound is irrigated and closed over a drain in the routine fashion. A sterile dressing is applied and the knee is placed in a post-op hinged brace. There should be no weight bearing with crutches, initially. Follow-up radiographs should be taken at 2, 6, 8, and 12 weeks. Partial weight bearing may commence at 6 weeks w/adequate x-ray evidence. Full weight bearing can begin at at 8 weeks.
Arthrex has technically trained representatives to assist orthopedic surgeons in implementing new techniques and associated products. Please contact your local representative or Arthrex directly for additional information.
Western Hemisphere Arthrex, Inc. 2885 South Horseshoe Drive Naples, FL 34104 Phone: (941)643-5553 Fax:(941)643-7386 Email: Information@Arthrex.Com Eastern Hemisphere Arthrex, GmbH Liebigstrasse 13, D-85757 Karlsfeld/Munich, Germany Phone: +49-8131-59570 Fax: +49-8131-5957-631 Email: Information.Gmbh@Arthrex.Com