Oblique Osteotomy Research Articles

Subcapital Oblique Osteotomy for Correction of Bunionette Deformity

Many procedures have been described for correction of bunionette deformity. For symptomatic type I deformity, the authors have routinely performed a subcapital oblique osteotomy of the fifth metatarsal. The purpose of this study was to report the medium-term results of this procedure. This is a retrospective review of patients who underwent subcapital oblique osteotomy for correction of type I bunionette deformity. Patients were evaluated radiographically and clinically. Sixteen feet in 14 patients were available at final follow-up. At a mean 2.9-year follow-up, 88% of patients had good or excellent clinical result, 88% of patients had no limitation in activity, and mean pain score on a visual analog scale was 1.6 out of 10. Radiographically, a statistical difference was found when we compared the preoperative and 6-week follow-up fifth metatarsophalangeal angle; however, no statistical difference was found in the fourth to fifth intermetatarsal angle at any time or in comparison of the preoperative and final follow-up fifth metatarsophalangeal angles. We found the subcapital oblique osteotomy of the fifth metatarsal to provide reliable clinical results for correction of painful type I bunionette deformity. Level IV, retrospective case series.

A Modified Reduction Malarplasty Utilizing 2 Oblique Osteotomies for Prominent Zygomatic Body and Arch

The shape of the zygomatic body and arch have great influences to the facial contour of Orientals. The prominent zygoma makes the appearance look more fierce. Nowadays in China, the number of patients who underwent reduction malarplasty is increasing rapidly. Therefore, it is important to develop a reliable surgical procedure with small wound and good effects. Included in this report were 46 patients with prominent zygomatic body and arch treated between October 2007 and November 2010. Combined intraoral and extraoral approaches were used, and 2 oblique osteotomies were performed to anterior and posterior part of malar complex, respectively. The isolated zygoma segment was then internalized utilizing z-plasty for the posterior end and inward sliding and internal fixation for the anterior end. The extraoral approach was made through a small temple incision. All patients were subjectively satisfied with the postoperative appearance. Their face contours were effectively improved by the modified procedure. One patient had short-term numbness of the medial zygomatic region skin; no other complications were observed during the follow-up period. This surgical procedure was carried out using combined intraoral and extraoral approaches. No visible scars left on the face. After 2 oblique osteotomies were made, the anterior inward sliding and posterior z-plasty could be easily performed to the isolated zygomatic bone. No segmental bone removal was required. The natural curve of the face contour was maintained while the malar complex was reshaped. We concluded that it is an effective and safe reduction malarplasty technique for Orientals.

Foot Deformity Correction with Hexapod External Fixator, the Ortho-SUV Frame™

External fixators enable distraction osteogenesis and gradual foot deformity corrections. Hexapod fixators have become more popular than the Ilizarov apparatus. The Ortho-SUV Frame™ (OSF; Ortho-SUV Ltd, St. Petersburg, Russia), a hexapod that was developed in 2006, allows flexible joint attachment such that multiple assemblies are available. We assessed the reduction capability of several assemblies. An artificial bone model with a 270-mm-long longitudinal foot was used. A 130-mm tibial full ring was attached 60 mm proximal to the ankle joint. A 140-mm, two-third ring forefoot was attached perpendicular to the metatarsal bone axis. A 130-mm, two-third ring hindfoot was attached parallel to the tibial ring. A V-osteotomy, which was combined with 2 oblique osteotomies at the navicular–cuboid bone and the calcaneus, was performed. The middle part of the foot, including the talus, was connected to the tibial ring. We assessed 5 types of forefoot applications and 4 types of hindfoot applications. The range of correction included flexion/extension in the sagittal plane, adduction/abduction in the horizontal plane, and pronation/supination in the coronal plane. Additionally, we reported the short-term results in 9 clinical cases. The forefoot applications in which the axis of the hexapod was parallel to the axis of the metatarsal bones had good results, with 52°/76° for flexion/extension, 48°/53° for adduction/abduction, and 43°/51° for pronation/supination. The hindfoot applications in which the hexapod encircled the ankle joint also had good results, with corresponding values of 47°/58°, 20°/35°, and 28°/31°. Clinically, all deformities were corrected as planned. Thus, multiple assemblies and a wide range of corrections are available with the OSF.

Comment on Bao et al.: Lesser trochanteric osteotomy in total hip arthroplasty for treating CROWE type IV developmental dysplasia of hip

Dear Editor, First we would like to congratulate Bao et al. [1] on the publication of the article entitled “Lesser trochanteric osteotomy in total hip arthroplasty for treating CROWE type IV developmental dysplasia of hip”. Although the technique of lesser trochanteric osteotomy has been well described in this study, there are still three problems which need to be further addressed by the authors: The greater trochanter fracture. The technique of lesser trochanteric osteotomy includes sequential bone cutting at the level of the subtrochanteric diaphysis, while leaving the greater trochanter intact, as shown in Fig. 1 in [1] this article. It is likely to cause a greater trochanter fracture when the femoral stem is inserted, which is going to compromise the abductor attachment. How can the greater trochanter be protected from being broken? The soft tissue tension. Subtrochanteric osteotomy has been demonstrated to be a safe and effective technique for soft tissue release in performing total hip arthroplasty (THA) for high dislocated developmental dysplasia of the hip (DDH). The neurovascular tissue is well protected as the femur is shortened when the femoral head is distalised and reduced into the true acetabulum [2]. In the technique described, however, the femoral length is in fact not reduced or shortened to a much lesser extent compared as a result of subtrochanteric osteotomy. The soft tissue tension remains high after the reduction of the hip. How can the authors address the high soft tissue tension remaining and the low incidence of neurovascular injuries as reported in this article? The anteversion angle of the acetabular cup and femoral stem. Due to the deformity of the acetabulum and proximal femur, it is not easy to determine the anteversion angle of the prostheses which is of vital importance in preventing dislocation of the hip. How are the prostheses set at a proper angle to construct a stable articulation? We agree with the viewpoint that the lessor trochanteric osteotomy could be adopted to avoid subtrochanteric nonunion when performing the step-cut or oblique osteotomy, but the proximal femur and abductor protecting technique needs to be advanced in future studies.

A New Elevating Metatarsal Osteotomy: Geometrical Design and Applications

For metatarsalgia and lesser toe deformities, a commonly performed procedure is the Weil osteotomy, which inevitably depresses the metatarsal head, changing the intrinsic muscle axis and generating phalanx extension. The objective of this study is to present a new metatarsal osteotomy that shortens or lengthens and elevates the metatarsal head, the elevating metatarsal osteotomy (EMO), with its geometrical analysis and possible applications. A geometrical model was designed, planning an oblique subcapital osteotomy with slice resection and distal displacement. A trigonometric analysis was done to calculate how to shorten, elevate, or lengthen the metatarsal head. The EMO elevates the head in one-third of the width of the resected slice. Distal and dorsal displacement of the metatarsal head results in an elevation and lengthening of the metatarsal bone (60% elevation and 65% lengthening). Performing an elevating metatarsal osteotomy will lengthen and elevate the metatarsal head, which sometimes is necessary when treating toe deformities and instability.

Subcaptial Oblique Fifth Metatarsal Osteotomy Versus Distal Chevron Osteotomy for Correction of Bunionette Deformity

The aim of this study was to compare a distal subcapital oblique fifth metatarsal with a distal chevron osteotomy for correction of bunionette deformity. Twenty cadaveric feet were randomly assigned to undergo either a subcapital oblique or chevron osteotomy of the distal fifth metatarsal. Radiographic measurements, including 4-5 intermetatarsal angle (IMA), fifth metatarsophalangeal angle (5-MPA) and foot width, were compared between the 2 groups. Foot width and 5-MPA was significantly decreased in both groups with no difference between the groups. The 4-5 IMA was not significantly altered in either group. Decrease in foot width and 5-MPA was similarly achieved with either distal chevron or subcapital oblique osteotomy of the fifth metatarsal in normal cadaveric specimens. No significant difference was found between the 2 techniques in any of the radiographic parameters measured.

Optimal Fixation of Oblique Scaphoid Fractures: A Cadaver Model

Acute scaphoid fractures are commonly fixed with headless cannulated screws positioned in the center of the proximal fragment. Central placement of the screw may be difficult and may violate the scaphotrapezial joint. We hypothesize that placement of the screw through the scaphoid tuberosity will achieve perpendicular fixation of an oblique waist fracture and result in more stable fixation than a screw in the center of the proximal fragment. We designed oblique osteotomies for 8 matched pairs of cadaver scaphoids and fixed each specimen with a headless cannulated screw. In 1 specimen, we positioned the screw at the center of the proximal fragment; we placed its matched pair perpendicular to the fracture. The perpendicular screw was directed through the scaphoid tuberosity. We placed the specimen under the increasing load of a pneumatically driven plunger. We compared stiffness, load, distance at failure, and mechanism of failure between the central and perpendicular screw groups. We found no difference between groups. Stiffness was identical in both groups (131 N/mm) and load to failure was similar (central screw, 137 N vs perpendicular screw, 148 N). In this biomechanical model of an unstable scaphoid fracture, we found that similar stability of fixation had been achieved with a screw perpendicular to the fracture plane with entry through the tuberosity, compared with a screw in a central position in the proximal fragment. This study suggests that placing the screw through the tuberosity, perpendicular to a short oblique fracture, will not impair fixation stability. Percutaneous fixation of scaphoid fractures has become popular although it is technically challenging. An easier distal approach through the tuberosity, without violating the scaphotrapezial joint, may not impair the fixation stability of an oblique fracture.

Effect of mini-fragment fixation on the stabilization of medial malleolus fractures

Oblique fractures of the medial malleolus can arise from the application of axial force at various anatomic positions of the ankle, including supination-external rotation, pronation-external rotation, or pronation abduction. Although a variety of techniques exist to provide fixation of horizontal medial malleolus fractures, the optimal technique and pattern for internal fixation remains unclear. The aim of this study was to evaluate the mechanical properties of four different fixation methods for fractures of the medial malleolus. Identical oblique osteotomies were created in synthetic distal tibiae using a jig. The specimens were divided into four fixation groups: contoured 2.0 mm mini-fragment T-plate, figure-of-eight tension band wire, construct two parallel 4.0 mm cancellous screws, and two divergent 4.0 mm cancellous screws. The specimens were tested using offset axial tension at 10 mm/min until 2 mm of joint line displacement. The average stiffness in tension and force at 2 mm of joint line displacement of the plate construct was significantly greater than any of the other constructs (p < 0.05), whereas the average stiffness in tension of the other three groups were not significantly different from each other (p > 0.05). Using a contoured 2.0 mm mini-fragment T-plate as the method of fixation resulted in an at least 25% stiffer construct during tension and required at least 24% more force for 2 mm of joint line displacement when compared with more traditional methods of fixation in an osteotomy model of an oblique medial malleolus fracture.

Asymmetric osteotomy of the spine for coronal imbalance: a technical report

Technical report on the surgical technique of asymmetric osteotomy of the spine for coronal imbalance. To describe a successful method of performing asymmetrical pedicle subtraction osteotomy (APSO) through a posterior only approach. Rigid coronal deformity of the spine can be sharply angulated and can create significant coronal imbalance. Surgical correction is the only definitive treatment of restoring the balance as bracing is unhelpful. Corrective surgery can be anterior or posterior. The literature on the methods of surgical correction of rigid coronal deformities of the spine is limited. Unlike osteotomies for sagittal imbalance, blunt dissection of the anterior cortex is necessary in asymmetrical osteotomy to allow resection of the anterior cortex for closure of the wedge. We describe a method by which we performed this in the thoracic and lumbar spine with case examples. After insertion of pedicle screws, laminectomy and unilateral facetectomy of the proposed level of osteotomy is performed. Next, dissection lateral to the pedicle and vertebral body is performed bluntly with mastoids to reach the front of the anterior cortex and confirmed with fluoroscopy. An oblique osteotomy including the lateral and posterior cortex is performed above and below the pedicle under imaging. The osteotomy site is closed through unilateral compression. Satisfactory correction of coronal deformity can be achieved with APSO from an isolated posterior approach. In contrast to sagittal osteotomies, blunt dissection along the anterior cortex is necessary to allow safe resection of anterior cortical bone for closure of the wedge.

The influence of different osteosynthesis configurations with locking compression plates (LCP) on stability and fracture healing after an oblique 45° angle osteotomy

BackgroundLocking compression plates are used in various configurations with lack of detailed information on consequent bone healing. Study designIn this in vivo study in sheep 5 different applications of locking compression plate (LCP) were tested using a 45° oblique osteotomy simulating simple fracture pattern. 60 Swiss Alpine sheep where assigned to 5 different groups with 12 sheep each (Group 1: interfragmentary lag screw and an LCP fixed with standard cortex screws as neutralisation plate; Group 2: interfragmentary lag screw and LCP with locking head screws; Group 3: compression plate technique (hybrid construct); Group 4: internal fixator without fracture gap; Group 5: internal fixator with 3mm gap at the osteotomy site). One half of each group (6 sheep) was monitored for 6weeks, and the other half (6 sheep) where followed for 12weeks. MethodsX-rays at 3, 6, 9 and 12weeks were performed to monitor the healing process. After sacrifice operated tibiae were tested biomechanically for nondestructive torsion and compared to the tibia of the healthy opposite side. After testing specimens were processed for microradiography, histology, histomorphometry and assessment of calcium deposition by fluorescence microscopy. ResultsIn all groups bone healing occurred without complications. Stiffness in biomechanical testing showed a tendency for higher values in G2 but results were not statistically significant. Values for G5 were significantly lower after 6weeks, but after 12weeks values had improved to comparable results. For all groups, except G3, stiffness values improved between 6 and 12weeks. Histomorphometrical data demonstrate endosteal callus to be more marked in G2 at 6weeks. Discussion and conclusionAll five configurations resulted in undisturbed bone healing and are considered safe for clinical application.

Modifies Oblique Proximal Tibial Osteotomy for Deformity Correction of Tibia Vara (Blount Disease)

Background: In Blount’s disease, there is a complex three-dimensional deformity which typically includes varus, internal rotation, and (sometimes) procurvatum. The best way to obtain correction is with simple procedure carried out as high in the tibia as possible to promote rapid union, quick remodeling, and with minimal proximal shaft deformity. Patients and methods: 17 patients with tibia vara underwent corrections of deformity associated with tibia vara by modified Rab proximal tibial oblique osteotomy at our hospital. In twelve patients the deformity was bilateral and it was unilateral in the other five patients, with a total of 29 tibiae. They were ten boys and seven girls with a mean age at surgery of 3 years 6 months (range, 3 years 2 months to 4 years 11 months). The patients were in stage III of the Langenskiold classification (1952) of the disease. Results: According to Schoenecker’s criteria, 100% of the patients in this study had a good result. Radiologically healing was achieved in all osteotomies with the desired correction of deformity within twelve weeks in all the 17 patients with no complication. Conclusion: The modified Rab oblique proximal tibial has the advantage of allowing both angular and rotational correction with a high degree of success.

下顎枝垂直骨切り術 －手術術式－

The use of Subcondylotomy procedure, the origin of Intraoral vertical osteotomy （IVRO）, has been limited by concerns of potential complications. These concern include condylar position and poor bone contact. Herbert and Nickerson modified the condylotomy procedure by converting it to variation of the IVRO and utilized maxillo-mandibular fixation and rehabilitation to minimize complication. Subsequent reports have confirmed that the IVRO also relieves pain and dysfunction a high percentage of time and, in addition, markedly reduces the complication. Today, IVRO has been using for the correction of Dentofacial Deformity in the world. Because of the primary advantage of this technique compared to the sagittal split osteotomy is the much less frequent and less severe damage to the mandibular nerve. However the protective surgical management was not performed, the potential for bleeding with a vertical oblique osteotomy has been reported to be greater than with the SSRO, because the superior aspect of the osteotomy is carried into the sigmoid notch. I will introduce the safety and ensuring technique of IVRO for correction of dentofacial deformity.

A case report: Metatarsal shortening oblique osteotomy for rheumatoid forefoot deformities with internal fixation by a headless compression screw

A case report: Metatarsal shortening oblique osteotomy for rheumatoid forefoot deformities with internal fixation by a headless compression screw

Distal tibial oblique osteotomy with early weight bearing exercise

Distal tibial oblique osteotomy with early weight bearing exercise

Tme diagnosis and treatment of nontrauatic ulnocarpal impaction syndrome

Objective To explore the characteristics of non-traumatic ulnocrpal impaction syndrome without typical X-ray features and discuss the diagnosis criteria and treatment methods.Methods Fifty-five cases of definite diagnosis of ulnocarpal impaction syndrome treated from October 2003 to October 2010 were retrospectively reviewed.25 cases were identified as with no definite trauma history and no typical X-ray features.Based on the diagnostic criteria described by Kostas,ulnocarpal stress test,dynamic positive ulnar variance and early MRI and wrist arthroscopty findings of these 25 cases were analyzed.All the cases underwent ulnar shortening osteotomy with compression plate fixation,among which 16 with transverse osteotomy (Darrow procedure) and 9 with oblique osteotomy (Rayhack procedure).Results were scored using the criteria described by Darrow.Results Among the 25 cases,ulnocarpal stress test was positive in 84％ of the cases,dynamic positive ulnar variance was present in 52％ of the cases,and abnormal changes in signal intensity occurred in theMRI findings of 82％ cases.These changes were always located at the ulnar side of the lunate and (or) at the waist or bottom of the triquetrum.TFCC degeneration and cartilage degeneration on ulnar head and lunate were present in wrist arthroscopy of all the cases.Follow-up period ranged from 4 to 48 months with an average of 26months.Bone union was achieved in all 25 cases.Union time averaged 4.5 months after transverse osteotomy and 2.5 menthe after oblique osteotomy.Function evaluation revealed excellent results in 7 cases,good results in 15 cases,fair results in 2 cases and poor results in 1 case.The overall good-excellent rate was 88％.There were no complications.The clinical outcomes were satisfactory.Conclusion It is difficult to differentiate non-traumatic ulnocarpal impaction syndrome from other etiologies of ulnar side wrist pain due to its lack of a traumatic history and typical X-ray features.Ulnocarpal stress test,dynamic positive ulnar variance and early MRI imaging studies can improve the early diagnosis rate.Wrist arthroscopy can allow assessment of pathology and be used as a diagnostic tool for differential diagnosis.Ulnar shortening osteotomy is an effective method and oblique osteotomy is recommended. Key words: Carpal joints; Diagnosis; Ulna; Osteotomy; Nontraumatic; Ulnocarpal impaction

Total Hip Arthroplasty With Shortening Osteotomy in Congenital Major Hip Dislocation Sequelae

We retrospectively evaluated the postoperative results of total hip arthroplasty (THA) in patients presenting with Crowe group IV dislocated hips. Overall, results were compared with regard to the type of osteotomy performed (Z or oblique) to define the correct indications for surgical technique and choice of prosthetic implant. Thirty-three subtrochanteric shortening and derotational osteotomies in primary THA were performed in 26 patients secondary to congenital hip dislocation. A Z osteotomy was performed in 14 cases and an oblique osteotomy in 19. The surgical approach was direct lateral, and surgery was aimed at restoring the anatomic hip center. Femoral and acetabular fixation was uncemented. The most used stem was the S-ROM (DePuy, Leeds, United Kingdom), and the couplings used were ceramic-ceramic (7 cases), ceramic-polyethylene (3 cases), metal-polyethylene (15 cases), and metal-metal (3 cases). Mean follow-up was 88±45 months. According to the Merle D'Aubigné score, the overall clinical results were good in 23 cases, satisfactory in 6, and fair in 4. Union of the osteotomy occurred in 97% of cases, and the mean time required for osteotomy union was 6±2 months without significant differences between Z and oblique osteotomies. At last follow-up, there was loosening of 1 cup and 1 stem, and revision was necessary. Twelve percent of patients experienced postoperative dislocation and 9% developed neuropraxia of the femoral nerve. The clinical and radiological results were similar in both groups, with a high rate of pain relief, an improvement in limb-length discrepancy, and reduced limping, leading to a smaller or no insole. Currently, the more complex Z osteotomy has been abandoned, because a modular stem prosthesis with metaphyseal sleeve allows the oblique osteotomy to be used with an easier and shorter surgical procedure.

Mechanical Comparison of Two Types of Fixation for Ludloff Oblique First Metatarsal Osteotomy

The Ludloff oblique metatarsal osteotomy is an effective method to correct hallux valgus deformity, although a number of problems have been associated with it, including inherent instability, delayed union, dorsal malunion, and fixation failure. The purpose of the present study was to compare the mechanical characteristics of fixation of the Ludloff osteotomy in 20 identical synthetic bone models, 10 fixated using 2 screws (group I) and 10 fixated using 2 screws augmented with a mini locking plate (group II). Each specimen was loaded to failure, and the mean average load to failure, stiffness, and absorbed energy to failure were compared using unpaired Student’s t test. The mean average stiffness of the Ludloff osteotomy fixed with 2 screws (group I) and with the supplementary mini locking plate (group II) was 172.7 ± 31.7 N/mm and 193.3 ± 39 N/mm, respectively ( p = .21). The mean average load to failure for groups I and II was 278.4 ± 64.4 N and 356.2 ± 77.9 N, respectively ( p = .025). The mean average energy absorbed before failure for groups I and II was 506.7 ± 206.4 Nmm and 769.8 ± 339.4 Nmm, respectively ( p = .05). The use of a medially applied supplementary mini locking plate offers a simple and effective method to improve the mechanical stability of the Ludloff oblique osteotomy.

Revisiting the Supraforaminal Horizontal Oblique Osteotomy of the Mandible

Today, the most common orthognathic procedure for correction of mandibular deformities is the bilateral sagittal split osteotomy, also called sagittal ramus osteotomy. Permanent injury to the mandibular nerve (V3) is one of the main complications, with a reported incidence between 5% and 30%. Orthognathic surgery using sagittal ramus osteotomy of the mandible as the procedure of choice should be re-evaluated because of the complexity and the relatively high risk of damage to the inferior alveolar nerve. Surgical techniques that allow for accurate condylar positioning with a lower risk of inferior alveolar nerve injury should be considered. The aim of this study is to present a retrospective case series using the previously described horizontal osteotomy of the mandibular rami along with modern-day technical advances that make this procedure safe, reliable, and reproducible. We performed a modified approach to the supraforaminal horizontal oblique osteotomy of the mandible with a condylar positioning device, endoscopy, and a surgical navigation system. This technique was performed in 17 consecutive patients. Postoperatively, we measured the amount of surgical movement of the mandible, monitored the mandibular nerve, and evaluated bone healing during removal of the osteosynthesis plates. In all 17 treated patients there was uneventful wound healing, and no patient had permanent nerve alteration. The mean movement of the mandible was 7.48 mm (SD, 2.1 mm), with a range from 3.0 to 10.5 mm. The mean follow-up was 19 months. The main purpose of the surgical navigation was the translation of the planned osteotomy line from the computed tomography scan to the surgical site during the operation. This was performed to prevent a large gap between the bone segments at the osteotomy site. The supraforaminal approach with a condylar positioning device appears to be an appropriate way to prevent injury to the inferior alveolar nerve during orthognathic surgery of the mandible while maintaining centric positioning of the condyle and obtaining good bony union.

Use of a new curvilinear distractor to repair mandibular defects in dogs

We have investigated the feasibility of using a new curvilinear distractor to repair mandibular defects in 6 mature male dogs. A mandibular defect was created by an oblique osteotomy between the distal planes of the bilateral second premolars, and a transport disc 10mm wide was made. After a 7-day latency period, distraction was activated at 0.5mm/12h and consolidation lasted for 6 or 12 weeks. Three dogs were killed after 6 and 12 weeks’ consolidation for gross, radiographic, and histological observations to be made. Curvilinear distraction osteogenesis was successful in 5/6 animals. At both time points smooth curved bone had been restored in the distracted areas, and radiographic and histological examination showed that the generated bone was similar to normal bone after 12 weeks’ consolidation. These results suggest that the curvilinear distractor could complete curvilinear distraction osteogenesis in dogs’ mandibles.

Das Parallelsägeblatt

For shortening osteotomy, two exactly parallel osteotomies are needed to assure a congruent adaption of the shortened bone after segment resection. This is required for regular bone healing. In addition, it is difficult to shorten a bone to a precise distance using an oblique segment resection. A mobile spacer between two saw blades keeps the distance of the blades exactly parallel during an osteotomy cut. The parallel saw blades from Synthes® are designed for 2, 2.5, 3, 4, and 5 mm shortening distances. Two types of blades are available (e.g., for transverse or oblique osteotomies) to assure precise shortening. Preoperatively, the desired type of osteotomy (transverse or oblique) and the shortening distance has to be determined. Then, the appropriate parallel saw blade is chosen, which is compatible to Synthes® Colibri with an oscillating saw attachment. During the osteotomy cut, the spacer should be kept as close to the bone as possible. Excessive force that may deform the blades should be avoided. Before manipulating the bone ends, it is important to determine that the bone is completely dissected by both saw blades to prevent fracturing of the corticalis with bony spurs. The shortening osteotomy is mainly fixated by plate osteosynthesis. For compression of the bone ends, the screws should be placed eccentrically in the plate holes. For an oblique osteotomy, an additional lag screw should be used.