Greater frequency of distraction accelerates bone formation in open-wedge proximal tibial osteotomy with hemicallotasis

Background?In chickens, increased distraction frequency stimulates bone formation in distraction osteogenesis.Patients and methods?We investigated the effect of two different distraction frequencies on bone formation in the distracted portion, and on the time of removal of the fixator, in open-wedge osteotomies of the proximal tibia with hemicallotasis (HCO). The study included 20 consecutive patients (20 knees) who underwent HCO for medial osteoarthrosis of the knee. 10 knees were distracted at a rate of 0.25 mm four times a day (the 4-step group); and the other 10 knees were distracted at a rate of 0.125 mm eight times a day (the 8-step group).Results?There were no significant differences in the preoperative FTAs or the correction angles between the two groups. At all intervals until 6 weeks after the completion of distraction, bone mineral density in the distraction gap was significantly higher in the 8-step group than in the 4-step group. The average time in external fixation was 78 (SD 5) days in the 8-step group as compared to 89 (SD 6) days in the 4-step group, a significantly shorter time.Interpretation?Our findings indicate that an increase in the distraction frequency in HCO provides better bone formation, resulting in a shorter external fixation period.     

Experimental epiphysial distraction producing and correcting angular deformities

Angular deformities of the distal radius of 15 sheep were induced by asymmetrical epiphysial distraction. Eleven sheep were between 10 and 20 weeks old; four were older than 24 weeks. Gradual distraction on the medial side of the limb caused partial separation of the epiphysis from the metaphysis, resulting in a valgus deformity. The distraction device was removed three to six weeks after insertion. Spontaneous correction of angulation with growth occurred in the younger sheep; but when the induced valgus angle exceeded 20 degrees correction was poor. In two sheep further distraction was applied on the lateral side and this produced complete correction. Premature closure of epiphyses did not occur after distraction and longitudinal growth of the bone remained normal. In the older sheep asymmetrical distraction succeeded in inducing angulation in only one case, and correction was poor.     

Distraction osteogenesis for the treatment of post traumatic complications using a conventional external fixator. A novel technique

PURPOSE: To evaluate the clinical results of post traumatic complications treated by the author's own technique using an AO/ASIF conventional external fixator (without special distraction device). MATERIALS AND METHODS: There were 70 patients (77 limbs) with an average of 26.8 years (range, 4-54). There were 33 femurs, 43 tibias and one ulna. The following post traumatic complications were treated: 14 limb shortening, 20 nonunion, 28 malunion 14 infected open fractures with bone loss and 1 chronic osteomyelitis. Linear lengthening was performed in 29 limbs, acute de-rotation and subsequent lengthening in two limbs, gradual angular correction in six limbs, combined gradual angular correction and subsequent lengthening in 10 limbs, combined acute angular correction and subsequent lengthening in eight limbs and 22 limbs with bony defects were treated with the technique so-called "bone transportation". All of the limbs were treated with an AO/ASIF conventional external fixator, using the author's own technique with distraction rate of 1 mm in one step on alternate day (1 mm/48 h). RESULTS: A new bone formation in the distraction gap was achieved in 73 of the 77 limbs. Four cases without consolidation were successfully treated with an iliac bone graft combined with plating or reapplication of the external fixator. Average new bone formation was 5.6 cm (range, 1-17 cm). The average follow-up period was 10.8 months (range, 1-71 months) after removal of the fixator. The average healing time was 244.7 days (range, 60-836 days) and the healing index was 50 days/cm (range, 17-100 days). In the group with associated angular deformity the mean correction was 18.5 degrees (range, 10-40). CONCLUSIONS: The author's technique of distraction osteogenesis, using a conventional external fixator combined with a distraction rate of 1 mm/48 h (1 mm/step) adequately treated the post traumatic complications. No extra equipment was needed other than readily available AO/ASIF fixation systems. The described technique, using an AO/ASIF fixator as a lengthening apparatus was simple and cost-effective.     

Greater frequency of distraction accelerates bone formation in open-wedge proximal tibial osteotomy with hemicallotasis

BACKGROUND: In chickens, increased distraction frequency stimulates bone formation in distraction osteogenesis. PATIENTS AND METHODS: We investigated the effect of two different distraction frequencies on bone formation in the distracted portion, and on the time of removal of the fixator, in open-wedge osteotomies of the proximal tibia with hemicallotasis (HCO). The study included 20 consecutive patients (20 knees) who underwent HCO for medial osteoarthrosis of the knee. 10 knees were distracted at a rate of 0.25 mm four times a day (the 4-step group); and the other 10 knees were distracted at a rate of 0.125 mm eight times a day (the 8-step group). RESULTS: There were no significant differences in the preoperative FTAs or the correction angles between the two groups. At all intervals until 6 weeks after the completion of distraction, bone mineral density in the distraction gap was significantly higher in the 8-step group than in the 4-step group. The average time in external fixation was 78 (SD 5) days in the 8-step group as compared to 89 (SD 6) days in the 4-step group, a significantly shorter time. INTERPRETATION: Our findings indicate that an increase in the distraction frequency in HCO provides better bone formation, resulting in a shorter external fixation period.     

Bone formation and remodeling after symmetric and asymmetric physeal distraction

Bone formation after symmetric and asymmetric physeal distraction was studied in growing sheep. After gradual distraction by external fixation, separation of the growth plate occurred. Fluorescence microscopy, microradiography, and histomorphometric methods were used to study neometaphysis formation. The bone was formed from the inner layer of the periosteum to encircle the distraction area, where the osteogenesis occurred according to the collagen bundles. At consolidation, the distraction area was composed of lamellar trabecular and partly woven bone. The bone trabeculae in the distraction area were thicker than in the control radius. After asymmetric physeal distraction, spontaneous correction of the formed angulation occurred through remodeling and asymmetric physeal growth. Although local physeal changes were noted histologically, enchondral growth usually continued after distraction.     

Distraction Histiogenesis: Principles and Indications

Distraction histiogenesis is a biologic phenomenon that can be utilized to induce the formation of new bone and soft tissue. This technique has been used after corticotomy or osteotomy of bone to treat patients with limb-length inequality, angular deformities, segmental bone loss, nonunions, and contractures. A distraction force is applied with an external fixator, such as the Ilizarov circular fixator or a uniplanar fixator. The authors review the extensive preoperative planning required, the performance of osteotomy, the application of external fixators, and the timing between the osteotomy and the initiation of correction (the latency phase). The subsequent distraction phase involves active lengthening, transport, or angular correction through frequent small steps (e.g., 0.25 mm every 6 hours). This results in the formation of new bone, or regenerate, in longitudinal columns along the plane of distraction. The consolidation phase begins after the desired correction has been achieved; this period allows for maturation of the regenerate and corticalization before fixator removal.     

Telescoping vascularized fibular graft: a new method for treatment of congenital tibial pseudarthrosis with severe shortening

Vascularized fibular grafts have proved reliable in the treatment of congenital pseudarthrosis of the tibia with a high success rate. However, severe shortening cannot be primarily corrected by this technique and requires a second-stage lengthening procedure. Ilizarov's method allows correction of shortening and axial malalignment together with the non-union. However, in the dysplastic type with severe shortening, corticotomy of the affected bone may result in delayed consolidation or recurrence of disease. In addition, the large distraction distance (equal to the amount of shortening plus the resulting defect after excision of the pseudorthrosis site) requires prolonged frame application, which may not be tolerated by the patient. We present a new technique combining vascularized fibular graft and Ilizarov distraction that allows simultaneous correction of shortening while treating the non-union in a single-stage operation. This method avoids corticotomy in the congenitally affected bone and markedly shortens the time of frame application.     

Interfragmentary movements in the early phase of healing in distraction and correction osteotomies stabilized with ring fixators

BACKGROUND: Experimental analyses have demonstrated the impact of mechanical conditions on bone healing. In critical clinical cases the mechanical conditions may be even more demanding than those in experimental studies. This study set out to examine the gap movements in distraction and correction osteotomies and to determine the suitability of initial fixation. PATIENTS AND METHODS: Interfragmentary movements, ground reaction forces, and stability (ground reaction force divided by interfragmentary movement) were measured in 18 patients with tibial osteotomies stabilized by Ilizarov hybrid constructs until either bone union or conversion to internal fixation occurred (9 distraction treatments, 9 correction osteotomies). Consolidation was determined by clinical evaluation and standard radiographic techniques. RESULTS: In both groups cocontraction led to gap movements comparable to level walking. Although the in vitro stiffness was slightly increased in the correction constructs, the interfragmentary movement in vivo was initially comparable between the groups. Patients undergoing distraction returned later to full weight bearing than patients undergoing correction treatment. In the correction group the stability increased with treatment time, while in the distraction group the stability remained relatively small. CONCLUSIONS: The in vivo mechanical conditions in challenging clinical cases appear far more demanding than those in experimental studies. In distraction, mechanical conditions at the defect appear to be more critical than during correction osteosynthesis. According to the persistence of shear motion, even after 80 days of treatment, it may from the clinical point of view be important to maintain interfragmentary compression during the whole healing process and thereby reduce shear.     

Hemichondrodiastasis for the treatment of genu varum deformity associated with bone dysplasias

Hemichondrodiastasis has been reported for treatment of angular deformities in children close to skeletal maturity. The use of distraction through the physis in younger children was not recommended. The authors report three children 3 to 7 years of age who underwent bilateral proximal tibial hemichondrodiastasis for correction of genu varum due to bone dysplasia. Ilizarov external fixators were applied in all cases. The patients underwent gradual angular correction at a rate of 0.5 mm/d. Distraction was continued until a normal mechanical axis was achieved. Normal alignment was achieved in two patients and slight overcorrection in the third. The patients were followed for 3 to 11 years, and no adverse affects on the physis were identified. This is the first report of physeal distraction in patients this young. Our results are good, and we believe that hemichondrodiastasis can be safely used for correction of angular deformities in young children.     

Humeral lengthening and deformity correction

Nine patients with achondroplasia and one patient with Apert syndrome underwent the surgical lengthening of both humerus and simultaneous correction of both associated bone deformity. An unilateral external fixator was applied to the lateral aspect of the humerus with four half-pins and percutaneous predrilling osteotomy was performed at the apex of flexion deformity of the bone. During the waiting period before distraction, the flexion deformity of the distal humerus was corrected using an additional external fixator. Slow gradual distraction was subsequently carried out at a rate of 0. 25 mm every 6 hours. The average lengthening was 8 cm (range 7.5 to 9 cm), the overall treatment time 312 days (range 192 to 406 days), and the average healing index 39.0 days/cm. The average correction of the elbow flexion deformity was 20 degrees. We believe this treatment is useful to improve the function of the arms and the activity of daily living for the patients with bilateral short humeri.     

牵张成骨矫治猕猴腭部软硬组织缺损的组织学及荧光标记研究

目的 观察猕猴牵张成骨术整复腭裂过程中,新骨组织形成与改建活动的特点,探讨新骨生成的规律.方法 建立猕猴腭裂动物模型,以牵张成骨术整复其腭部软硬组织缺损,以每天2次、每次0.4 mm的速率牵引,直至骨运送盘移动关闭裂隙后原位固定.分别于固定期第1、2、4、6、8、12及24周取材,每时相点3只实验动物.取材前6 d,实验组动物(21只)均肌肉注射四环素(30 mg/kg)标记.各组标本包埋切片行组织学及荧光标记观察.结果 与实验对照组及空白对照组(动物各2只,同法标记)对比.结果 实验组骨运送盘移动至裂隙对侧关闭缺损,牵开间隙内以膜内成骨方式原位成骨,成功整复腭部软硬组织缺损.牵张成骨术后固定期从1至24周逐渐延长,呈现出成骨-改建-成熟的动态变化过程:牵张区新骨形成的量及其钙化程度不断增加,与此同时,新骨组织亦呈现不断改建成熟的趋势,软组织随着新骨的形成不断地延伸,对照组裂隙无法自行修复.结论 应用牵张成骨术整复腭裂缺损,在良好的固定下,通过膜内成骨的方式,新骨不断的成熟和改建,直至成功修复软硬组织缺损.     

Le Fort Ⅲ型截骨中位牵引矫正面中份发育不全

目的探索使用中份骨骼均衡前移的牵引技术，以矫正面中份后缩畸形。方法牵引系统由面弓、牙科正畸用的橡皮圈和经鼻孔插入的骨内承力牵引装置组成。对18岁以上的严重面中份发育不全畸形的患者3例，行Le Fort Ⅲ型截骨。显露两侧梨状孔缘，用粗裂钻在梨状孔的外下缘外侧约8mm处钻孔，斜向穿过上颌窦前壁和鼻腔侧壁的骨质达下鼻道。经双侧鼻孔引入骨内承力牵引装置的挂钩，将挂钩插入梨状孔缘的骨孔内。手术后第3天用连接于面弓和骨牵引钩的正畸橡皮圈进行牵引。结果患者面容和咬合关系完全恢复正常，面部上、中、下各部的前后关系协调，鼻梁及鼻下部挺拔。结论Le Fort Ⅲ型截骨后弹力牵引能够有效地矫正严重面中份发育不全畸形。新的牵引技术牵引力点适中，能够使面中份骨骼平衡前移；避免对牙齿牵拉所造成的不利改变；利用鼻孔的自然结构，不留可见瘢痕。     

Noninvasive Quantitative Assessment of Bone Healing After Distraction Osteogenesis

One of the greatest challenges of limb lengthening and deformity correction is deciding when the bone has healed enough to remove the external fixator. Standard radiography is the most common imaging method used to assess bone healing after distraction osteogenesis because it is widely available, cheap, and relatively safe. However, other imaging technologies and methods are being investigated that will help quantify bone healing after distraction osteogenesis, providing an objective method for deciding when it is appropriate to remove an external fixator. This review will examine the latest techniques used to assess bone healing after distraction osteogenesis including dual-energy X-ray absorptiometry scans, ultrasound, quantitative computed tomography, and digital radiography (X-ray). Recommendations for clinical practice will be outlined.     

Computer-assisted assembly and correction simulation for complex axis deviations using the Ilizarov fixator

In axis correction with the Ilizarov ring fixator, the correction results are often insufficient or there are unexpected translation effects, which can be causally attributed to wrong preoperative planning or inaccurate assembly. To avoid such results, computerised simulation was developed. Via digitalisation of the bone outlines traced from X-radiographs with an additional scale, preoperative correction planning can be performed, simulated with normal software. This can be used while constructing the apparatus and positioning the joints. In addition, the translation effect of the bone fragments can be simulated by arbitrarily choosing the pivot of the correction. In transferring the X-radiograph true to scale, one can compare the ring planes before and after correction. It is possible to estimate the necessary distraction as well as compression and thus the postoperative distraction mode. Using computerised planning, the apparatus construction can be optimised and complications caused by misplanning avoided. Not only the inexperienced user can benefit from this aid.     

Progressive forearm lengthening with an intramedullary guidewire in children: report of 10 cases

Indications for forearm lengthening are rare. Between 1994 and 1999, 10 forearm lengthenings were performed in seven children for functional reasons and/or esthetic discomfort. Only one of the two forearm bones was involved in the procedure in all cases. The technique consisted of a transverse osteotomy and progressive distraction after intramedullary nailing. When a bone axis correction was needed, it was performed with a substraction osteotomy in the initial osteotomy site. The distraction device was removed when bone healing was achieved. The authors noted the various complications and assessed the amount of elongation, bone healing, and potential bone axis deviation. Mean follow-up was 4.5 years. Mean elongation was 30.8 mm. Four bone grafts were needed for delayed union. No bone axis deviation was noted. An initial axial correction osteotomy allows an easier lengthening procedure. Use of an intramedullary wire avoids axis deviation. This technique can be helpful in malformative pathologies.     

Treatment of bone tumor using external fixator

External fixation has been widely used for the treatment of limb length discrepancy, deformity correction, and bone defect using distraction osteogenesis. We have been using this technique for the treatment of obstacles due to benign bone tumor and reconstruction after malignant bone tumor resection. In this paper, we introduce the usefulness of external fixation for the treatment of various benign bone tumors and limb salvage surgery for reconstruction after tumor resection using distraction osteogenesis, according to the tumor site. The advantages of external fixation for the treatment of benign bone tumor include a possibility of complex deformity correction without treating the tumor itself and reconstruction of the aggressive benign bone tumor as well as solid fixation with wires, even for weak bone due to benign bone tumors. The advantages of treating malignant bone tumor include regeneration of living bone of sufficient strength and durability, biological affinity, resistance against infection, and lifelong restored function. The disadvantages include delayed union at the docking site and pin-or wire-tract infection, patient's psychological stress, and the procedure is time consuming. We conclude that external fixation is very efficient for the treatment of benign and malignant bone tumors.     

头盆环牵引全脊柱截骨内固定治疗重度脊柱弯曲

[目的]介绍头盆环牵引全脊柱截骨加内固定治疗重度脊柱弯曲的手术方法,并总结185例重度脊柱弯曲的治疗结果。[方法]对重度脊柱侧弯患者,先用头盆环牵引,使重弯变为轻弯,以便置入器械的安装,再在头盆环牵引下进行截骨矫正畸形和内固定手术,术后继续配戴头盆环制动,术后第2d即可下床站立活动,给护理工作带来极大方便。[结果]作者自1983~2003年,采用此法治疗重度脊柱侧弯185例,平均矫正率是70.32%。脊柱截骨断端能达到坚固的骨性融合,矫正率丢失平均在5°以内,术后晚期并发脱钩者4例,均经再次手术固定解决,对矫正效果无影响。1例术后1年并发感染,拆除置入器械后,伤口很快愈合,X线所见植骨愈合良好。1例并发神经根疼痛,而后逐渐减轻,所有病例未见脊髓损伤和神经系统并发症发生。[结论]头盆环牵引加全脊柱截骨是治疗重度脊柱侧弯的有效方法,对那些仅用单纯器械无法安装,置入困难的病例,经头盆环牵引后,内固定器械容易安装,再加上全脊柱截骨,能使弯曲的脊柱进一步伸直,减轻了内固定器械所承受的负荷力,避免了脱钩断棍的发生,为治疗重度脊柱侧弯的有效手段。     

Therapieoptionen bei Brachymetatarsie

Brachymetatarsia can be congenital, idiopathic or secondary and describes an abnormal shortening of a metatarsal bone. The indications for treatment are not only due to cosmesis. The shortening of a ray changes the biomechanics of the foot and can lead to metatarsalgia. A frequent clinical feature is dorsal dislocation of a toe causing painful shoe conflict and disturbed proprioception. There are three main options for operative correction: lengthening osteotomy, interposition of a tricortical bone and gradual lengthening by callus distraction. While one stage lengthening procedures such as osteotomy and interposition are more appropriate for correction of moderate length deficiencies, the callus distraction method is more suitable for larger elongation. Common to all procedures is a long-term treatment with a high risk of different complications whereby patient compliance can be problematical.     

面中部牵引成骨术矫正综合征性面中部后缩畸形

目的 探讨牵引成骨术治疗面中部后缩畸形的可行性。方法 2001至2002年对4例Crouzon、Apert和Marfan综合征，并伴面中部后缩畸形的患者，分别行Le Fort Ⅲ内置式延长器(2例)、Le Fort Ⅲ水平外置式延长器(1例)、monobloc水平内置式延长器(1例)治疗，于截骨后4d开始牵引延长，速度为每天1mm。结果 按计划完成牵引，面中部前移8～20mm。面中部后缩畸形明显减轻，双侧对称，尤其眶、鼻根部效果更佳，随访4个月至1年，效果稳定。结论 骨牵引成骨术具有传统的植骨加坚强内固定的方法所无法比拟的优点，能较大范围前移面中部，是矫正各种发育不良造成的严重面中部后缩畸形的有效而可行的方法。     

Biomechanics of external fixation and limb lengthening

Surgeons who use external fixators for foot and ankle conditions need to understand the biomechanical principles to ensure good outcomes. Fixators can be used for fracture fixation, correction of contractures, distraction osteogenesis, and distraction arthroplasty. A two-ring fixator with wire fixation remains the gold standard with which all other frames are compared. Small changes in mechanical characteristics can have major implications on new bone or cartilage formation.