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  • 1.13 Authors Ronald J van Heerwaarden, Ate B Wymenga, Denise Freiling, Alex E Staubli 13 Supracondylar varization osteotomy of the femur withplate xation1Introduction The aim of varization osteotomy of the distal femur is to relievemedial closed-wedge osteotomy. Stabilization of the osteotomy lateral single-compartment degeneration at the knee by shiftingis achieved by application of conventional blade plates, the mechanical axis medially. Degeneration of the lateral knee angular-stable plates, or insertion of a distal femoral nail [1]. with valgus deformity is a frequent consequence of subtotal or total lateral meniscectomy. Valgus deformities that are In recent years incomplete open-wedge osteotomy through a posttraumatic or subsequent to growth disorders or partial lateral approach has gained increasing acceptance due to the epiphyseodesis also require surgical correction. development of spacer plates [2]. The authors have, however,observed that this technique may result in disturbed bone Varization osteotomy of the distal femur can be performed by a healing and symptoms at the lateral aspect of the femur due to medial closed-wedge or lateral open-wedge technique. Lessfriction as the iliotibial tract moves over the plate. In this frequently used dome osteotomies can also be performed in thechapter an improved technique for medial closed-wedge supracondylar region of the femur. Supracondylar varizationosteotomy is described that involves an incomplete osteotomy osteotomy of the femur today is generally performed as a and application of a special internal plate xator.2Principles of medial closed-wedge femoral osteotomy Stable osteosynthesis is of great importance in a supracondylarwith an intact lateral bone bridge is far more stable than a osteotomy of the femur as it permits undisturbed bone healingcomplete osteotomy that cuts through the lateral cortex. In and functional rehabilitation. In addition to the angled blade terms of closed-wedge osteotomies of the distal femur, an plate [311] , the curved semitubular plate [12, 13] and a moreoblique, proximal to distal, descending osteotomy will yield recently developed plate xator [14] can be considered for greater primary stability than a transverse osteotomy since the osteotomy stabilization. In biomechanical investigations osteotomy surfaces are more congruent and the medial cortical substantial differences have been found in the primary stability support is more secure [12, 15]. Primary stability is also of different xation methods, and these differences must bemarkedly increased by compression of the osteotomy surfaces, respected when planning postoperative rehabilitation [15]. whereby optimal cortical contact is essential for effectivecompression to avoid risk of overcorrection due to subsidence Apart from the xation technique, the type of osteotomy, its of the distal fragment into the proximal fragment. Compression orientation and localization also play an important role in pri- also accelerates bone healing and prevents delayed union and mary stability. An incomplete, medial closed-wedge osteotomy nonunion.147MOAK_chapter_13_T07.indd 14711/4/08 12:36:17 PM

2. 13 Clinical applicationsType, direction, and localization of the osteotomy as well asthe xation technique are very important for the primarystability of the osteotomy. An incomplete medial closed-wedge osteotomy with an intact lateral cortical bridge is farmore stable than an osteotomy that cuts through the bonebridge. Oblique, proximal to distal descending osteotomiesare more stable than transverse osteotomies.3Design of the fixed-angle plate fixator TomoFix MDF The specic plate xator TomoFix MDF was developed inscrews are inserted with the torque screwdriver and locked at collaboration with the Knee Expert Group (KNEG) of the AO. a xed angle in the conical threaded hole. Self-tapping locking It is a special spoon-shaped locking compression plate head screws are inserted in the distal part and self-tapping/self- (LCP) that has four threaded holes in the distal part and four drilling locking head screws combined with self-tapping screws combination holes in the proximal shaft (Fig 13-1). Alignmentwith predrilling in the proximal part. The proximal locking and angulation of the distal threaded holes are designed to t head screws can be anchored mono- or bicortically (Fig 13-2). the anatomy of the supracondylar zone of the distal femur. LeftSecondary correction loss during screw tightening is avoided and right versions facilitate correct positioning of the plate insince the xed-angle locking head screws do not develop a lag the anteromedial segment of the distal femur and securescrew effect. This feature permits stable xation of the TomoFix anchorage of the locking head screws in the condylar block.plate xator even in osteoporotic bone. Temporary insertion of Utilization of an LCP guide sleeve to predrill the screw holes a 3 mm spacer in the most proximal plate hole preserves the ensures correct alignment of the distal locking head screws. The periosteal blood ow. 148MOAK_chapter_13_T07.indd 148 11/4/08 12:36:17 PM 3. 13 13Supracondylar varization osteotomy of the femur with plate fixationa cbFig 13-1ad TomoFix MDF plate for closed-wedge correction osteotomy at themedial distal femur designed with four threaded holes in the distal part and fourcombination holes in the proximal part. da Plate xator for the left femur.b Plate xator for the right The drill sleeves are attached to the plate by application of the positioning device (black).a b c Fig 13-2ad TomoFix MDF plate with the bicortical (green) and monocortical (blue) locking head screws inserted. aMedial view. bFrontal view. cCaudal view. dAngulation of the locking head screws in the transverse plane in a bone model.d 149MOAK_chapter_13_T07.indd 149 11/4/08 12:36:17 PM 4. 13 Clinical applications4Indications and contraindications The indication for varization osteotomy of the distal femur and The preoperative range of motion at the knee should be at least plate xation is lateral single-compartment degeneration at the extension/exion 0-0-90. Extension and exion decits can knee with valgus deformity of the lower extremity. The patientbe corrected to some extent by the osteotomy involving should have a desire to be active and should not be older thanadditional wedge extraction in the sagittal plane. This requires 55 (female) to 60 (male) years of age. The procedure can be a complete femoral osteotomy. combined with other reconstructive measures in the lateral compartment, eg, osteochondral autogenous transplantation Contraindications include obesity, loss of the inner meniscus, (OATS), autogenous chondrocyte transplantation (ACT), arthrosis, or third degree cartilage damage of the medial and matrix-induced autogenous chondrocyte implantationcompartment as classied by Outerbridge [16] , or restricted (MACI). movement at the knee, especially an extension decit greater than 1520. The operation should not be performed if the Relevant symptomatic valgus deformities due to growth soft-tissue situation at the distal femur is inadequate or if there disorders or as the result of trauma should likewise be corrected is acute or chronic infection. In addition there should be no prior to the development of manifest arthrosis. Planning must nicotine abuse. always respect the need for the surface of the knee joint to be as horizontal as possible after correction. If there is a deformity Indications: Single-compartment lateral joint degeneration at the proximal tibia in addition to the femoral deformity, a with valgus deformity, patients aged 5560 years. double osteotomy must be considered since isolated varization Contraindications: Obesity, extension decit of >20, loss of the femur may lead to excessive deviation of the knee base-of the inner meniscus, third degree cartilage injury of the line from the horizontal, leading to long-term symptoms (seemedial compartment, or manifest arthrosis, insufcient chapter 14 Double osteotomies of the femur and the tibia).soft-tissue situation, and nicotine abuse.5Preoperative work-up Correction of axial deformity by osteotomy of the distal femurexpected postoperatively. Despite the submuscular approach, requires thorough preoperative planning. Full explanation ofrecovery of full exion may require a long rehabilitation the possible complications and risks must be given to the period. patient. This does not just include information on general risks such as vessel and nerve injuries, thrombosis, embolism,5.1 Preoperative diagnostics disturbed wound healing, early and late infections, but also theClinical examination includes assessment of the range of possibility of delayed bone healing. Hematoma at the distal motion and the laxity of the knee ligaments. The skin and thigh, protracted swelling, and lymph edema are often to be soft-tissue situation should be normal. Radiological diagnosis 150MOAK_chapter_13_T07.indd 150 11/4/08 12:36:30 PM 5. 13 13 Supracondylar varization osteotomy of the femur with plate fixation requires views of the knee in three planes and an x-ray ofRadiological planning of a supracondylar closed-wedge femoral the whole leg under loading. Additional information about the osteotomy is shown in Fig 13-3. The same principles apply as for extent of damage of the knee can be derived from a weight-the preoperative planning of proximal tibial head osteotomy. bearing view in 45 exion, known as the Rosenberg view, andThe correction angle for the osteotomy is calculated on the basis MRI, but these procedures are not essential. Stress views may of the preoperative x-rays and is reproduced intraoperatively be valuable if there is also ligament laxity. It is essential to take with the help of an appropriate saw guide and a calibrated soft-tissue and ligament laxity with asymmetrical opening ofgoniometer. In addition, the height of the osteotomy wedge the joint into account during preoper