Introduction. The objective of this study is to report the first cases of femoral lengthening in children using Ilizarov fixator. Materials and Methods. We carried out a retrospective study about the cases of femoral lengthening done in 2010 to 2020 in our BARI-ILIZAROV Orthopaedic centre Dhaka. Results. 48 lengthening were done during this period using Ilizarov fixator. The procedure was done incongenital bone diseases in 20 cases and after a distal femoral epiphysiodesis in 10 cases. The mean age at surgery was 12.8 years. Lengthening was required in all patients and an axis correction was required in 16 of 26 cases. The mean lengthening was 5.9 cm. The healing index was 45.5 day/cm (25.5–62). We noticed 8 knee stiffness and 5 broken wires. Knee Stiffness were corrected by Judet'squadricepsplasty and 6 broken wires were replaced by new wires. The goal of lengthening was reached in all cases. The goal of axis correction was reached in 98.5% of cases. Conclusions. Ilizarov technique allows to do accurate lengthening and axis correction and it is a unique reliable external fixator for femoral lengthening in children

Introduction. Infected big gap non-union of femur and tibia are difficult to treatment because of infection, bone loss, shortening, poor sift tissue over and deformity. Step by step management and definitive treatment by Ilizarov fixator was achieved in our cases. Materials and Methods. A long defect which is more than 10cm in femur and tibia because of infection and gap, tumor resection, traumatic loss, which is very difficult to treat by conventional method and that's why we treated that type defect by Tibialization of fibula with Ilizarov technique. Management of infected big gap non-union of the femur include debridement and bone transport by Ilizarov technique by using Ilizarov fixator we can correct deformities, regenerate new bone without bone grafting, correct LLD and patient can weight bear during the course of treatment. We retrospectively reviewed records of 246 consecutive patients who underwent distraction osteogenesis using Ilizarov compression-distraction device for infected big gap INU of femur and tibia from 2000 to 2020. Results. All healed with the application of Ilizarov fixator, 5 needed reapplications of Ilizarov to achieve 100% union. 210 were excellent, 25 good and 6 were fair by ASAMI criteria. Mean Ilizarov duration was 366 days (130–250). Mean 8.2 cm length was achieved in the regenerate. Conclusions. A well plan step by step Ilizarov technique to cover infected gap non-union of femur and tibia is an excellent method in challenging cases. Excellent results cannot be achieved with conventional methods but can be easily achieved with Ilizarov technique within 1–2 years

Introduction. Reconstruction of large defect of tibia following infection is considered as one of the most difficult problem facing the orthopaedic surgeon. Amputation with modern prosthetic fitting is a salvage procedure to treat big defects, which gives a functional result with unpredictable psychological impact. Materials & Methods. Between January 2000 and January 2021, 56 patients (30 males and 26 females) with big defects following infection and post traumatic injury of the tibia were treated. The mean age of the patients at the time of surgery was 20.5 years (4–24 years). The fibula was mobilized medially to fill the defect and was fixed with Ilizarov fixator. The average size of the defects reconstructed was 18.5 cm (17–20 cm). Results. The average time for complete union was 8.6 months (range, 5–9 months). At final follow-up all patients had fully united. We found leg length discrepancy in 52 patients and that was corrected by re-lengthening of the solid new regenerate bone. Conclusions. The Ilizarov method has been shown to be an effective method of treating Tibialization of fibula for reconstruction of big tibial defects

Introduction. Ilizarov fixators are reliant on tensioned fine wires for stability. The tension in the wires is generated using specific tensioning devices. Loss of wire tension over time may lead of loss a stability and complications. A series of in vitro experiments were undertaken to explore wire tensioner accuracy, the impact of fixation bolt torque and initial tension on loss of tension in ilizarov constructs under static and dynamic loads. Materials & Methods. Medical grade materials were applied to a synthetic bone analogue using surgical instruments in all experiments. Bolt torque was fixed at 6, 10 or 14 Nm using a torque limiting wrench. Wire tension was assessed using a strain measurement bridge. Wires were tensioned to 90, 110 and 130kg as measured by a commercial dynamometric tensioner. Static and dynamic testing was undertaken using an instron testing machine. Cyclical loads from 50–750N were applied for 5000 cycles. Results. Actual wire tension was approximately 15% less than indicated by the tensioner device. Using fixation bolt torques of 10Nm and 14Nm achieved final wire tensions of around 60% and 80% of that applied at 90 and 130kg of applied tension. Static load testing demonstrated self stiffening to similar levels in all pre-tensions. Dynamic testing demonstrated significant loss of tension, most of which occured in the first 3 cycles, inversely proportional to the tension initially applied. Conclusions. These experiments provides insight into the effect of initially applied wire tension on Illizarov mechanical performance. It is important surgeons understand how the different ways that these devices are applied affects mechanical performance. Further research examining what factors affect performance across different manufacturers equipment would therefore be relevant, alongside the development of novel fixation methods to reduce wire slippage and the further development of equipment for clinical use

Introduction. We assessed the role of four different High Tibial osteotomies (HTOs) for medial compartment osteoarthritis of knee (MCOA): Medial Opening Wedge High Tibial Osteotomy (MOWHTO), Focal Dome Osteotomy with Ilizarov Fixator (FDO-I), intra-articular, Tibial Condylar Valgus Osteotomy with plating (TCVO-P) and intra-articular plus extra-articular osteotomy with Ilizarov(TCVO-I); in correcting three deformity categories: primary coronal plane varus measured by Mechanical Axis deviation (MAD), secondary intra-articular deformities measured by Condylar Plateau Angle (CPA) and Joint Line Convergence Angle (JLCA), and tertiary sagittal, rotational and axial plane deformities in choosing them. Materials and Methods. We retrospectively studied HTOs in 141 knees (126 patients). There were 58, 40, 26, and 17 knees respectively in MOWHTO, FDO-I, TCVO-P and TCVO-I. We measured preoperative (bo) And postoperative (po) deformity parameters. Results. Average age was 56.1, average follow-up was 44.6 months. Mean bo-MAD in MOWHTO, FDO-I, TCVO-P, and TCVO-I were 8.8, −14.7, −11.5, −30.8% respectively. po-MAD was close to Fujisawa point in all except TCVO-P (45.2%). CPA corrected from −4.9° to −1.4° (p=0.02)and JLCA from 5.6° to 3.2° (p=0.001); CPA was better corrected by Intra-articular osteotomies (p=0.01). Conclusions. MOWHTO corrects isolated mild primary varus deformities (bo-MAD≥ 0%). Primary varus (bo-MAD= −25% −0%) with associated tertiary sagittal, rotational, or axial deformities, without secondary intra-articular deformities needed FDO-I. Primary varus (bo-MAD= −25% −0%) with secondary intra-articular deformities, without tertiary deformities, corrected well with TCVO-P. TCVO-I corrects severe primary varus (bo-MAD< −25%) with large deformities in secondary and tertiary categories

Introduction. Circular frame fixation has become a cornerstone of non-union and deformity management since its inception in the 1950s. As a consequence of modularity and heterogenous patient and injury factors, the prediction of the mechanobiological environment within a defect is subject to wide variations in practice. Given these wide range of confounding variables, clinical and cadaveric experimentation is close to impossible and frame constructs are based upon clinician experience. The Finite Element Analysis (FEA) method provides a powerful tool to numerically analyse mechanics. This work aims to develop an FEA model of a tibial defect and predict the mechanical response within the construct. Materials and Methods. The geometry of a tibia was acquired via CT and a series of bone defects were digitally created in the tibial diaphysis. A 4-ring, 10-wire Ilizarov fixator was constructed using 180mm stainless steel rings and 1.8mm stainless steel wires tensioned to 1200N. An axial load (800N) was applied to simulate single leg stance of an 80kg patient. The magnitude of displacement was measured for defects with varying sizes (5–40mm). A numerical analysis was performed in large-strain regime using open-source FEA library (MoFEM). Results. Defect size did not effect displacement, but significantly influenced strain. Measured displacements were 5.72–5.78mm, however strain ranged from 14.5–100%. Moreover, it was found that bone material properties also have no significant impact on the results. Conclusions. Accounting for FEA assumptions, this model predicted a strain environment which was above expected favourable range for bone healing. The addition of graft within the environment is likely to change the mechanobiological environment which warrants further investigation. We plan to develop this model to answer further research questions in the limb reconstruction discipline and validate its accuracy with mechanical data. We believe the presented approach can be a useful tool for investigating the performance circular frames

Introduction. Objective was to assess clinical results of treatment of Infected Non Union (INU) of long bones, using Antibiotic Cement Impregnated Nail (ACIN), a single or two staged approach, Stage 1 - Debridement, eradication of infection, primary stabilization with (ACIN). 2nd Stage - Definitive stabilization and early rehabilitation. Methods. 185 cases of infected non-union of long bones from Jan 2002 to Jan 2009 were treated in this hospital. 46 females and 139 males, age varied from 17–65 years (Avg. 40). Tibia was the commonest bone to be affected, followed by femur & humerus. The control of infection was by debridement, antibiotic cement impregnated K-nail (ACIN) insertion with or without Ilizarov ring fixator application, second stage treatment by definitive internal fixation and bone grafting was done if required. Average duration of follow up, was 26 months (14–58 months). Main outcome measurements were assessment of bone healing, functional outcome, healing time and complications. Results. Out of the 185 cases treated in our institute 174 (93.7%) patients achieved union at an average of 8 months. 2 limbs with non union tibia fractures were amputed on demand by patients, 2 limbs developed severe edema, 7 patients did not achieve union, inspite of repeated procedures. Infection was controlled early especially in Type 1 non unions. 5 patients had persistent infection though mild inspite of 2 or 3 surgeries of exploration and curettage. Discussion and conclusion. The two staged procedure described gives satisfactory results. Antibiotic and cement impregnated nails and beads achieve good infection control without any complications and reduce the healing time. Ilizarov fixator helps in stabilization, compression, deformity correction at the same time and plays a significant role in the path to union. Fixator should be removed as early as possible to avoid restriction of movements

Aim. Infected segmental defects are one of the most feared complications of open tibial fractures. This may be due to prolonged treatment time, permanent functional deficits and high reinfection and non-union rates. Distraction osteogenesis techniques such as Ilizarov acute shortening with bifocal relengthening (ASR) and bone transport (BT) are effective surgical treatment options in the tibia. The aim of this study was to compare ASL with bone transport in a consecutive series of complex tibial infected non-unions and osteomyelitis, for the reconstruction of segmental defects created at surgical resection of the infection. Method. In this single centre series, all patients with a segmental defect (>2cm) of the tibia after excision of infected non-union or osteomyelitis were eligible for inclusion. Based on clinical features, bone reconstruction was achieved with either ASR or BT using an Ilizarov fixator. We recorded the external fixation time (months), the external fixation index (EFI), comorbidities, Cierny-Mader or Weber-Cech classification, follow-up duration, time to union, number of operations and complications. Results. Overall, 43 patients with an infected tibial segmental defect were included. An ASR was performed in 19 patients with a median age of 40 years (range: 19 – 66 years). In this group, the median bone defect size was three cm (range: 2 – 5 cm); and the median frame time eight months (range: 5 – 16 months). BT was performed in 24 patients with a median age of 44 years (range: 21 – 70 years). The median bone defect size was six cm (range: 3 – 10 cm), and the median frame time ten months (range: 7 – 17 months). The EFI in the ASR group and the BT group measured 2.2 months/cm (range: 1.3 – 5.4 months/cm) and 1.9 months/cm (range: 0.8 – 2.8 months/cm), respectively. The comparison between the EFI of the ASL group and the BT group showed no statistically significant difference (p=0.147). Five patients of the ASR group (7 surgeries) and 19 patients of the BT group (23 surgeries) needed further unplanned surgery (p=0.001). Docking site surgery was significantly more frequent in BT; 66.7%, versus ASL; 5.3% (p=0.0001). Conclusion. Acute shortening/relengthening and bone transport are both safe and effective distraction osteogenesis techniques for the treatment of infected tibial non-unions. They share similar frame times per centimetre of defect. However, ASR demonstrated a statistically significant lower rate of unplanned surgeries

The segmental bone transport allows the reconstruction of large scale bone defects resulting after a redical debridement due to an infection or after trauma. We use the Ilizarov fixator for the segmental transport. The part of the bone that has to be moved through the defect is pulled by a lateral and a medial towing rope. To determine continuously the forces of tension in the wires and to detect early complications of the bone transport we implanted in each wire a load cell with a resistance strain gauge. The knowledge of the resulting forces leads to the development of an automatic forced controlled bone transport. Since 09/2004 we have measured the forces of tension in the wires in 77 patients undergoing a segmental bone transport due to a long-extending osteomyelitis. The average age was 47,2 (6 to 68). In 12 patients we had to treat a bone defect of the thigh (average size of the defect 12,5 cm), in 55 patients 56 large scale bone defects of the lower leg (average size of the defect: 8,6 cm ranging from 6,0 to 20,0 cm). We implanted a load cell with a resistance strain gauge in the lateral and medial towing rope. This way we could, after converting the measured values from analog to digital, the impacting forces. In all patients we were able to meausure continuously rising forces of tension. Lwe noticed forces which didn´t change much. At the end the bone transport we again found rising forces of tension. We noticed higher forces in the lateral wires, on femur and on tibia. Due to the measurement of the acting forces we were abel to perform a bone transport without close X-ray-monitoring. Complications such as premature ossification of the new building bone were identified and treated in an early stage.at. We developed a theoretical model drawing into consideration the interfering forces caused by the regenerating bone, the soft tissue, the friction of the wire, adherend soft tissue and geometry otf the wire. The forces calculated using this model were similar to the acting forces we found when measuring the forces of the bone transport. We now record the data on memory cards. A control of the data is possible over long-distance. We now started a model of an automatic bone transport controlled by the the acting forces. Our aim is to perform such an automatic bone transport in patients

We report on the clinical, radiographic and functional outcomes after salvage arthrodesis for complex ankle and hind-foot problems - the Portsmouth experience with the Ilizarov ring fixator. 11 patients underwent ankle and hind-foot (tibio-calcaneal) arthrodeses using an Ilizarov ring fixator between 2006 and 2010. The indications included failed fusion after primary arthrodesis, sepsis complicating internal fixation of fractures, talar avascular necrosis and failed total ankle arthroplasty (TAR). All patients had undergone multiple previous surgeries, which had failed. There were 8 males and 3 females in this group. Average age of the patients was 58 (43 years – 77 years) Mean follow up was 36 months (7 – 60 months). Mean frame time was 24 weeks (15 – 36 weeks). BMP 2 (Inductos) was used in three cases. The procedure was combined with a proximal corticotomy and lengthening in 2 patients who had undergone a talectomy and tibio-calcaneal fusion. There were no major complications apart from minor pin site infections requiring oral antibiotics. There were no deep infections, thromo-embolic issues, CRPS, or functional problems on account of limb shortening. Patients were assessed clinically, radiologically and using functional outcome scores - EQ50 and AOFAS. Solid arthrodesis was achieved in all but one patient who was subsequently revised with a hind-foot nail. All patients were satisfied with their overall improvement in pain and function. We conclude that this is an effective salvage technique for complex ankle and hind-foot problems in patients with impaired healing potential, insufficient bone stock and progressive deformity

Purposes of the study. To assess safety, lengths gained, frame time and perform cost analysis of the technique of submuscular plating to the femur and tibia following distraction osteogenesis. Introduction. Since 2005 we have performed submuscular plating to the femur and tibia after distraction osteogenesis in order to shorten time in external fixator. Aim. To assess safety, lengths gained, frame time and perform cost analysis. Methods. Retrospective analysis using notes and digital radiographs, with cost codes for 2011 prices. Patients. 23 patients (14 male), mean age 11 (range 4 to 17). 14 diagnosed as congenital longitudinal deficiency. Total 37 bones lengthened (14 femur and tibia, 7 tibia only, 2 femur only). Ilizarov fixator most commonly used for tibia, LRS fixator for femur. Results. Mean length gained 68 mm per patient, 43 mm per bone. Mean frame time 121 days. Fixator index 0.59 months/cm per patient, 0.90 months/cm per bone. Mean cost £20100 per patient, £12500 per bone, £2800 per cm length. Cost attributable to plating £5100 per patient, £3300 per bone. Complications: 5/24 had pinsite infections, 2/24 required tendon releases, 1/24 had deformity, 1/24 sustained a fracture proximal to femoral plate. No deep infections. Conclusions. Plating after lengthening is a safe procedure with no deep infections. The frame time is low (0.6 months/cm per patient) but increases overall costs by an extra £5000

The ipsilateral and contralateral fibulae have been used as a vascularised bone graft for loss of tibial bone usually by methods which have involved specialised microvascular techniques to preserve or re-establish the blood supply. We have developed a method of tibialisation of the fibula using the Ilizarov fixator system, ipsilateral vascularised fibular transport (IVFT), and have used it in five patients with massive loss of tibial bone after treatment of an open fracture, infected nonunion or chronic osteomyelitis. All had successful transport, proximal and distal union, and hypertrophy of the graft without fracture. One developed a squamous-cell carcinoma which ultimately required amputation of the limb. The advantage of IVFT is that the fibular segment retains its vascularity without the need for microvascular dissection or anastomoses. Superiosteal formation of new bone occurs if the tibial periosteal bed is retained. Other procedures such as corticotomy and lengthening can be carried out concurrently

Background. Arthrogryposis Multiplex Congenita is a rare congenital disorder associated with multiple musculoskeletal contractures which causes substantial morbidity. Knee involvement is commonly seen among children with arthrogryposis, with flexion contracture being the most frequent. The purpose of this study was to assess the effectiveness of orthopaedic procedures, namely distal femoral supracondylar extension osteotomy and/or Ilizarov external fixator, on the ambulation status of children with knee flexion contracture and whether any functional gains are maintained at the latest follow-up. Methods. Fifteen patients were identified and their medical records reviewed. The mean age at their first surgery was 7.6 years (range, 2-16 years). The etiology for all patients was amyoplasia. The mean length of follow-up was 58 months (range, 12-117 months). Contractures were treated with femoral extension osteotomy (n=8), Ilizarov external fixator (n=2), or both (n=5). Results. Pre-operatively, 11 patients were non-ambulatory, three patients were household ambulators, and one patient walked with orthoses in the community. There was an average of 1.5 knee surgeries done per patient. At the latest follow-up, nine patients were ambulatory with technical aids, two patients were household ambulators, one patient used a wheelchair but was independent for transfers, and three patients remained non-ambulatory. The mean flexion contracture prior to the first surgery was 62.8 ± 26.7 degrees. Post-operatively, the mean flexion contracture was 13.5 ± 16.4 degrees. At the latest follow-up, the mean flexion contracture was 33.8 ± 23.6 degrees. There were complications in three patients which included infected hardware, transient neurological compromise, and pressure sores, which eventually all resolved. Conclusion. early and aggressive orthopaedic management of flexion contractures in children with arthrogryposis is supported by our findings, and may contribute to functional gains

Aims. Since 2005 we have performed submuscular plating to the femur and tibia after distraction osteogenesis in selected cases in order to shorten the time in external fixator. The aim was to assess safety, lengths gained, frame time and perform cost analysis. Methods. Retrospective analysis using notes and digital radiographs, with cost codes for 2011 prices. 23 patients (14 male), mean age 11 (range 4 to 17) were analysed. 14 were diagnosed as congenital longitudinal deficiency. Total 37 bones lengthened (14 femur and tibia, 7 tibia only, 2 femur only). Ilizarov fixator most commonly used for tibia, LRS fixator for femur. Results. Mean length gained 68mm per patient, 43mm per bone. Mean frame time 121 days, with mean 75 days of lengthening, and mean 46 days between the cessation of lengthening and the plating procedure. Fixator index 0.59 months/cm per patient, 0.90 months/cm per bone. Mean cost £20100 per patient, £12500 per bone, £2800 per cm length. Cost attributable to plating £5100 per patient, £3300 per bone. Complications: 5/24 had pinsite infections, 2/24 required tendon releases, 1/24 had deformity, 1/24 sustained a fracture proximal to femoral plate. No deep infections. In terms of patient satisfaction, families of patients who had also undergone a prior lengthening with frame only, 80% preferred plate after lengthening. Conclusions. Plating after lengthening is a safe procedure with no deep infections. The frame time is low (0.6 months/cm per patient) but increases overall costs by an extra £5000 per patient. There is room to improve the fixator index further if the time between cessation of lengthening and the plating procedure (currently 46 days) is shortened

Aims

Excision of chronic osteomyelitic bone creates a dead space which must be managed to avoid early recurrence of infection. Systemic antibiotics cannot penetrate this space in high concentrations, so local treatment has become an attractive adjunct to surgery. The aim of this study was to present the mid- to long-term results of local treatment with gentamicin in a bioabsorbable ceramic carrier.

Patient's non acceptance of a bulky external fixator, the incidence of fractures of the regenerate, muscle transfixion giving rise to contractures especially in the Tendo Achilles, increased index of consolidation and the frequency of infections has made Limb lengthening with external fixators alone unpopular. In a retrospective study, we evaluated the technique of limb lengthening over a sub muscular plate combined with Ilizarov external fixator as an alternative to external fixator alone and whether the combined procedure is successful in reducing the external fixator period. 15 patients (14 with length discrepancy in the lower limb and 1 with low stature) and a total of 16 limbs (15 tibiae and 1 femur) were lengthened over a sub muscular plate fixed on the proximal segment followed by corticotomy and application of external fixator. Lengthening was achieved at 1 mm/day followed by distal segment fixation with three or four screws on reaching the target length. The pre operative target length was successfully achieved in all patients at a mean of 4.4 cm (2.2 to 6.5 cm). The mean duration of external fixation was 59.2 days (33 to 107 days) with the mean external fixation index at 16.7 days/cm (10.95 to 23.78). Infection complicated the procedure in two patients and one patient had mild Tendo Achilles contracture. Lengthening over a plate drastically reduces the time external fixator needs to worn and is preferred by patients to limb lengthening over an external fixator alone. patient Lengthening over a plate provides an alternative method for limb lengthening, can be applied to children with open physes and to deformed bones. [Lengthening over a Plate]

Tibial fractures complicated by bone and/or soft tissue loss present a great challenge. Traditional methods of limb reconstruction are lengthy and may not yield satisfactory functional results. Despite its tremendous contribution to the management of this condition, the Ilizarov technique of bone transport has several problems and difficulties. The present study was carried out between 1997 and 2002 and included 21 patients with tibial fractures complicated by bone and soft tissue defects as a result of open fractures or surgical debridement of infected non-unions. The bone loss ranged from three to eleven cm. (average 4.7 cm.). Ages ranged from 12 to 54 years (average 28.8 years). The follow-up ranged from 24 to 75 months. The procedure included resection of all devitalised tissues, acute limb shortening to close the defect, application of the external fixator and metaphyseal osteotomy for re-lengthening. In all patients the fractures united with well aligned limbs. Acute limb shortening of up to six cm. was done in the lower third of the leg. Limb lengthening was done in all cases and ranged from 3 to 9.5 cm. (average 4 cm.). An Ilizarov external fixator was used in nine cases (41%) and a monolateral fixator in 13 cases (59%) with a total of 22 applications. Residual leg length discrepancy of more than 3cm. occurred in four cases (19%). Complications included one refracture, one transient peroneal nerve palsy and one equinus contracture of ten degrees. Satisfactory results were obtained in 93% of cases. Acute limb shortening and re-lengthening converts a complicated limb reconstruction into a relatively simpler one of linear limb lengthening, without the difficulties of traditional Ilizarov techniques and eliminated the need for soft tissue flaps. It is better instituted early in the management of these cases to ensure better functional results and shorter treatment time

The purpose of this study was to evaluate and to compare the mechanical stability of external fixation with and without ankle spanning fixation using a foot plate in an in-vitro model of periarticular distal tibia osteotomy/fracture. Ten fresh frozen lower extremities (five pairs) with a simulated distal tibia osteotomy/fracture were stabilised with an Ilizarov hybrid fixator with and without a foot plate. All specimens were loaded using a servohydraulic load frame. Relative interfragmentary motions (vertical and horizontal translations, and rotation) were measured. Statistical analysis was performed as a paired t-test to compare the different frame constructs. A p<0.05 was considered indicative of a significant difference between fixator constructs. The vertical displacement measured at the centre of the distal fragment under load with the foot plate was such that the bone fragments became closer together (-0.83±0.64 mm). Loading of specimens without the foot plate resulted in distraction of the distal fragment (2.57±0.97 mm). The difference was statistically significant (p<0.05). The horizontal displacement of distal fragment with (1.12±0.98 mm) was not significantly different from the motion without (1.19±1.23 mm) a foot plate and was in the anterior direction in both cases. Loading of the construct with the foot plate caused sagittal plane angulation of the fragments with the osteotomy/fracture gap opening anteriorly (-1.15±0.61 deg.). Loading of the construct without a foot plate resulted in sagittal plane angulation of fragments with the gap opening posteriorly (4.49±0.45 deg.). These motion differences were statistically significant (p<0.05). There was not a statistically significant difference between the order of testing the construct with a foot plate and the construct without it (p>0.05). Fixators with ankle spanning using foot plates increase the mechanical stiffness of external fixation of periarticular distal tibia osteotomy/fracture

Purpose. Vitamin D is a key regulator of bone homeostasis. The enzyme CYP24A1 is responsible for transforming vitamin D into 24,25(OH)2vitD. The putative biological activity of 24,25(OH)2vitD remains unclear. Previous studies showed an increase in the circulating levels of this metabolite following a fracture in chicks. Our laboratory has engineered a mouse model deficient for the Cyp24a1 gene for studying the role of 24,25(OH)2vitD. We set out to study the role of 24,25(OH)2vitD in endochondral and intramembranous bone formation in fracture repair in this mouse model based on the results of the chick fracture repair study. Method. Wild-type and mutant Cyp24a1 gene deficient mice were subjected to two different surgical procedures to simulate bone development and fracture repair. To mimic endochondral ossification, we devised a modified technique to perform intramedullary nailing of a mouse tibia followed by an induced fracture. To evaluate intramembranous ossification, we applied distraction osteogenesis to a mouse tibia using a mini Ilizarov external fixator apparatus. Histomorphometric parameters and gene expression differences in fracture repair between the mutant mice and the wild-type controls were measured using micro computed tomography, histology and reverse-transcription quantitative PCR (RT-qPCR) respectively. Results. Quantitative histomorphometric results showed a delay in endochondral fracture repair in the mutant mice calluses as compared to the wild-type mice calluses. In the same model, gene expression of type X collagen in the callus was higher in the wild-type mice. These significant differences were fully rescued by injecting the mutant mice with exogenous 24,25(OH)2vitD. In the intramembranous bone formation model, we found a trend towards reduced bone formation in the gap created by the distraction process in the mutant mice as compared to the wild-type mice. However, the differences did not reach statistical significance. Conclusion. Our results support a role for 24,25(OH)2vitD in fracture repair which is more dominant in a chondrocyte-mediated bone formation pathway like endochondral ossification. Although our results did not reach statistical significance in the intramembranous ossification model, the observed trend suggests a potential role as well. Further study of the role of 24,25(OH)2vitD in bone healing has the potential to support novel approaches in accelerating bone formation and fracture repair

Aims

Double-level lengthening, bone transport, and bifocal compression-distraction are commonly undertaken using Ilizarov or other fixators. We performed double-level fixator-assisted nailing, mainly for the correction of deformity and lengthening in the same segment, using a straight intramedullary nail to reduce the time in a fixator.