Aims. Congenital pseudarthrosis of the tibia (CPT) has traditionally been a difficult condition to treat, with high complication rates, including nonunion, refractures, malalignment, and leg length discrepancy. Surgical approaches to treatment of CPT include intramedullary rodding, external fixation, combined intramedullary rodding and external fixation, vascularized fibular graft, and most recently cross-union. The current study aims to compare the outcomes and complication rates of cross-union versus other surgical approaches as an index surgery for the management of CPT. Our hypothesis was that a good index surgery for CPT achieves union and minimizes complications such as refractures and limb length discrepancy. Methods. A multicentre study was conducted involving two institutions in Singapore and China. All patients with CPT who were surgically managed between January 2009 and December 2021 were included. The patients were divided based on their index surgery. Group 1 included patients who underwent excision of hamartoma, cross-union of the tibia and fibula, autogenic iliac bone grafting, and internal fixation for their index surgery. Group 2 included patients who underwent all other surgical procedures for their index surgery, including excision of hamartoma, intramedullary rodding, and/or external fixation, without cross-union of the tibia and fibula. Comparisons of the rates of union, refracture, limb length discrepancy, reoperations, and other complications were performed between the two groups. Results. A total of 36 patients were included in the study. Group 1 comprised 13 patients, while Group 2 comprised 23 patients. The mean age at index surgery was four years (1 to 13). The mean duration of follow-up was 4.85 years (1.75 to 14). All patients in Group 1 achieved bony union at a mean of three months (1.5 to 4), but ten of 23 patients in Group 2 had nonunion of the pseudarthrosis (p = 0.006). None of the patients in Group 1 had a refracture, while seven of 13 patients who achieved bony union in Group 2 suffered a refracture (p = 0.005). None of the patients in Group 1 had a limb length discrepancy of more than 2 cm, while ten of 23 patients in Group 2 have a limb length discrepancy of more than 2 cm (p = 0.006). In Group 1, four of 13 patients had a complication, while 16 of 23 patients in Group 2 had a complication (p = 0.004). Excluding removal of implants, four of 13 patients in Group 1 had to undergo additional surgery, while 18 of 23 patients in Group 2 had to undergo additional surgery following the index surgery (p = 0.011). Conclusion. A good index surgery of excision of hamartoma, cross-union of the tibia and fibula, autogenic iliac bone grafting, and internal fixation for CPT achieves union and minimizes complications such as refractures, limb length discrepancy, and need for additional surgeries

Introduction. Patient-reported outcome measures (PROMs) has gained momentum in the orthopaedic literature. The GOAL-LD (Gait Outcomes Assessment List for Limb Deformity) incorporates the framework of The WHO International Classification of Functioning, Disability and Health and correlates highly with the Paediatric Outcomes Data Collection Instrument (PODCI) when applied in a limb reconstruction setting. The Royal Children's Hospital Melbourne, Australia, supported by The University of Melbourne is designing and implementing a Limb Reconstruction Registry, prospectively enrolling patients with a number of key conditions and provide a mechanism for capturing surgical data and PROMs at regular follow-up intervals. LimbDREAM (The Limb Reconstruction Registry of Experience, Aspiration and Measures) has begun recruiting participants, and this paper serves as a narrative review of our design and implementation process. Materials & Methods. After provision of a research grant, audit was conducted to examine local case mix and estimate recruitment based on conditions selected. Literature review was focussed on (i) registries in the paediatric limb reconstruction domain and (ii) use of PROMs across conditions selected. A high-level process-flow chart was constructed in order to inform governance and staffing requirements in addition to REDCap Database structure. Local as well as scalable deployment was considered. Alpha and beta testing was performed by principal and associate investigators prior to participant recruitment. Results. Audit identified 6 condition streams for inclusion: Congenital limb deficiencies, congenital pseudarthrosis of the tibia, bone dysplasias, bone tumours, amputation, and complex deformity of other etiology. Literature review identified 20 PROMs used across these conditions, with limited validation studies and significant implementation heterogeneity. REDCap database design took longer than anticipated (planned 10 months, actual 18 months) before being recruitment ready, due to the complexity of ensuring data collection logic would work across highly diverse patient journeys. Initial recruitment across all streams has been promising. Email and text message reminders have proved helpful in increasing survey return rates. Conclusions. Prospective collection of PROMs as well as surgical data via a standardized dataset will provide the basis for future condition-specific research, with the ability to support nested trials. Implementation requires forethought with regard to time frames and staffing for non-automated steps as well as data integrity review. The next phase of the LimbDREAM project will be to integrate use of the Registry into our weekly Limb Reconstruction Meeting to ensure that operative plans and data are captured close to the point of care

Introduction. This is a report of the outcome of management of congenital pseudoarthrosis of the tibia (CPT) at skeletal maturity. Materials and Methods. Retrospective study. Inclusion criteria:. CPT Crawford IV. Skeletally maturity. Availability of radiographs and medical records. Outcome: union rate, healing time, residual deformities, ablation and refracture. Results. 23 patients who reached maturity were analysed. Time to union was 7.6 months. Union rate 70%. External fixation group: 7 patients, age 6.1 years, all united, 1 needed Bone graft. Average union time 8.2 months, no residual mal-alignment, no amputations, 2/7 needed corrective osteotomies and residual LLD in 2/7 < 1 cm. Numbers of surgery was 3. Vascularized fibular graft was done in 3 cases; all had failed previous attempts. Union time was 7 months. 2/3 united, 1 had amputation due to extensive disease. All patients had residual mal-alignment. Rodding group included 13 patients, age 3.2 years, union rate 61%, union time 8.3 months. Average LLD 1 cm with 1 patient LLD > 2 cm. Residual knee mal-alignment in 2/13, 4 had procurvatum and 55% of patients had ankle valgus. Fibula pseudoarthrosis. Refracture was reported in 53% of the rodding group. The causes of refracture were mal-alignment in 3, traumatic in 2 and idiopathic in 2. Total surgeries no 5. 2 patients had amputations after an unsuccessful 1. st. attempt. Our current trend of treatment was applied on 8 patients. They are not skeletally mature yet. the treatment combined excision of hamartoma, tibial rodding, wrapped periosteal graft with/out neutralization frame, and fibular fixation. Average age 3.8 years, union time was 10 months, Union rate 80%, no residual deformities. Conclusions. Our study shows the evolution of the treatment of CPT with increasing union rate, fewer residual deformities, and numbers of surgeries with more recent techniques

Aims: The purpose of this study is to to assess the surgical results, complications, and long-term results of vascularized fibula in the treatment of congenital pseudarthrosis of the tibia. Methods: Seven patients who had congenital pseudarthrosis of the tibia were treated consecutively at our clinic between 1992 and 2000 with free vascularized fibular graft. There were four females and three males. The mean age at the time of operation averaged 6.5 years (range 1–12 years). Four left tibias and 3 right tibias were involved. Stability was maintained with internal fixation in four patients, external fixation in two patients and intramedullary pin in one patient. Results: The average follow-up was 2.6 years (range 6 months to 8 years). In five patients, both ends of the graft healed primarily within 2.7 months (range 1.5 to 3 months), and hypertrophy of the fibular graft occurred rapidly with a well-formed medullary canal. In one patient the distal junction did not unite and although required three subsequent operations still not healed. Stress fracture occurred in one patient underwent four additional operations before union achieved. Conclusions: Despiting the continuing problems and the relatively high complication rate, the ultimate results with free vascularized fibula transplant are generally good specially as compared with published series in whom conventional grafting techniques had failed. However, even achieving union of pseudarthrosis is not enough for the resolution of this disease and is only half of the problem; the other half is to maintaining

This paper reviews the outcome of 13 children with congenital pseudarthrosis of the tibia after intramedullary rodding and autogenous bone grafting. The oldest patient was aged nine years at the time of surgery. The ages of the others ranged from 12 to 24 months. The oldest patient at follow-up was 18 years. All 13 had bone defect and angulation. Ten children had clinical features of neurofibromatosis. Ten had pseudarthrosis involving the distal third of the tibia, two the middle third and one the proximal third. Autogenous iliac crest chips were used following excision of fibrous tissue and dense and atrophic bone. Rodding was done across the ankle joint in 10 patients. Postoperatively an above-knee cast was applied for 6 to 12 months, after which an above-knee brace was used to protect the rodding. At follow-up, which ranged from 10 months to 16 years after surgery, all patients were fully weight-bearing and ambulant. Three patients were lost to follow-up after 2 to 4 years. Complications included refracture and rod breakage (two), rod migration (three), and growth retardation with shortening of up to 5 cm. Ten patients had ankle and subtalar joint stiffness and two had valgus deformities of the ankle. Three patients underwent repeat rodding and bone grafting. Radiological union was observed to be progressing in all patients. Intramedullary rodding of the tibia for congenital pseudarthrosis of the tibia is a simple procedure and can be repeated. It avoids prolonged hospital stay and permits early weight-bearing. Careful supervision is necessary, and until there are signs of good bony union, external support is mandatory

Congenital pseudarthrosis of the tibia remains difficult to treat. With variable success, children are subjected to many surgical procedures. We review our experience using titanium elastic nails in this condition. We have treated 10 patients, six boys and four girls. Five had associated neurofibromatosis and pseudarthrosis of the fibula. In seven children, a mean of four previous operations had been done. The mean follow-up time was 4 years. In our patients, union occurred at a mean of 18 weeks, with a mean limb length discrepancy of 3 cm. The range of movement in the knee and ankle was good. Our early results are encouraging

Aim. To determine the preferable treatment for congenital pseudarthrosis of the tibia, we retrospectively reviewed 19 patients (20 limbs) treated consecutively over a 22 year period (1988–2007). Fifteen were followed up to maturity. The patients were assessed for union, leg length discrepancy (LLD), ankle valgus, range of ankle movement and distal tibial physeal injury. Results. The median age at surgery was 3 years. At surgery nineteen of the tibiae had a dysplastic constriction with a fracture (Crawford II-C or Boyd II) lesion. To obtain union in the 20 tibiae, 29 procedures were done. Nine failed primarily and required a second procedure to obtain union. Older patients (≥ 5 years) had a significantly higher success rate. Excision, intramedullary rodding and bone graft (IMR) was done in 14 tibiae: 10 (71.4%) were successful. Six of 10 primary operations and all 4 secondary operations after a previous failed procedure were successful. Ipsilateral vascularized fibula transfer (IVFT) was successful in 5 tibiae (3 primary and 2 secondary). Ilizarov with bone transport only, failed in two patients. Ilizarov with excision, intramedullary rodding and bone graft with lengthening was successful in 2 of 5 cases (40%); two sustained fractures at the proximal lengthening site. A median leg length discrepancy (LLD) of 3 cms occurred post surgery which was treated with contralateral epiphysiodesis. At maturity 3 patients had a LLD of ≥ 2cms. Six limbs had ankle valgus and were treated with stapling and tibio-fibular syndesmosis. Decreased range of movement of the ankle (< 50%) occurred in 7 patients. Distal tibial physeal injury occurred in 4 patients and was associated with repeated rodding. Conclusion. We concluded that surgery should be delayed as long as possible. If there is adequate tibial purchase for the rod distally, IMR is the best option. If purchase is inadequate, Ilizarov with rodding will avoid ankle stiffness. Epiphysiodesis is preferable to lengthening because of the risk of fracture above the rod. IVFT is a good option as a secondary procedure. NO DISCLOSURES

Background: Recombinant bone morphogenic proteins (BMPs) are potent bone anabolic agents suggested for the treatment of orthopaedic complications associated with neurofibromatosis type 1 (NF1), in particular, congenital pseudarthrosis of the tibia. We have explored the effect of Nf1 haploinsufficiency on ex vivo and in vivo models of BMP-induced bone formation in Nf1+/− mice. Methods: Using an Nf1+/− knockout mouse model, we expanded primary cell cultures from calvarial and long bone osteoblasts and measured osteogenic markers, such as alkaline phosphatase and mineralization using Alizarin Red staining, and the responses of these markers to BMP-2 treatment. We also developed an in vivo muscle pouch heterotopic ossification model to assess the ability of BMP-2 to form bone. Results: Primary osteoblast cultures from Nf1+/− mice showed reduced ALP staining, ALP activity and mineralization, denoting an anabolic deficiency. Nf1+/− osteoblasts responded to BMP-2 treatment, although osteogenic markers were reduced compared to BMP-2 treated Nf1+/+osteoblasts. Heterotopic bone was induced in both genotypes by surgically implanting BMP-2, however less bone was formed in Nf1+/− mice than Nf1+/+ controls. Conclusion: These data indicate that BMP therapies have potential utility in treating orthopaedic defects in children with NF1, but that dosing may need to be optimized for this patient subgroup or that catabolism may need to be also controlled

Introduction and purpose: Large defects of diverse aetiology (traumatic, oncological, etc.) in long bones pose a number of difficulties for reconstruction because of their dual condition: structural and functional. The free fibular flap can be a useful method for reconstructing large defects in bones such as the tibia or humerus. We present our experience with 15 patients in whom this bone flap was used to reconstruct defects of different pathological origins. Materials and methods: Retrospective analysis of 15 patients between the ages of 6 and 55 in whom a vascularised fibular flap was used to reconstruct bone defects in the following locations and pathologies: Tibia: 7 cases of congenital pseudoarthrosis, 1 case of posttraumatic pseudoarthrosis, 1 case of firearm wound, 1 case of chronic osteomyelitis, 2 cases of Ewing’s sarcoma in the distal third of the tibia; Humerus: 2 cases of Ewing’s sarcoma; Radius: 1 case of osteosarcoma. Of the 15 cases 14 fibulae were used with a single bar, with different attachment methods, and one with a double bar. Results: The viability rate of the flaps was 100%, and adequate function was achieved in all cases except one case of posttraumatic pseudoarthrosis that required further procedures. Conclusions: The vascularised fibular flap is the best option for treating congenital pseudoarthrosis of the tibia and a good option for reconstruction after oncological bone surgery

Three or more years after completion of treatment, we re-examined 16 patients with orthopaedic problems associated with neurofibromatosis I (NF-I) who were treated at our institution between 1976 and 1999. Seven boys and five girls between the ages of 5 and 15 years presented with congenital pseudarthrosis of the tibia (CPT). All had undergone previous surgery elsewhere. The patients had typical skin lesions and the associated radiological appearances of pseudarthrosis of the tibia. There were two cystic types of CPT, five hourglass and five normotrophic types, mostly at the level of the distal third of the tibia. Primary consolidation of the CPT was not obtained in any patient. Three patients underwent below-knee amputation after multiple surgical procedures. Eight had consolidations of the pseudarthrosis after multiple operations, but all had residual deformities and/or shortening. One patient remained with a non-consolidation. The surgical procedures included intramedullary rodding with or without bone grafting, fibular bypass grafting, Soffield turn-about rodding, electrical stimulation, and, in patients seen since 1989, various Ilizarov techniques including lengthening and bone transport. Our results suggest that the best treatment of this perplexing paediatric orthopaedic problem remains undetermined. Considerations for the selection of treatment include the pathologic anatomic pattern of NF-I and the patient’s age and expectations. A National Orthopaedic Neurofibromatosis Register will be useful in the decision-making process

The bisphosphonate, pamidronate, has been used successfully in our hospital for the management of osteogenesis imperfecta with an excellent safety profile in growing children. We have performed several research studies on distraction osteogenesis in New Zealand white rabbits showing significant increases in new bone formation and the abolition of stress shielding osteopaenia using both pamidronate and zoledronic acid. Recent studies have shown that bisphosphonates positively effect osteoblasts as well as inhibiting osteoclastic bone resorption. We present a series of early cases where this research has been used in humans. Two cases of pamidronate assisted distraction osteogenesis are presented, one of which also had congenital pseudarthrosis of the tibia, which united after pamidronate administration. Two cases of post-traumatic avascular necrosis have been successfully treated such that osteolysis and collapse of the necrotic femoral head did not occur. Bisphosphonates may act to slow bone resorption while simultaneously increasing new bone formation, such that the mechanical integrity of the necrotic segment can be maintained during revascularisation. A randomised controlled trial of bisphosphonates in distraction osteogenesis at our hospital has now received ethical approval. Newer bisphosphonates have proven their clinical value in osteogenesis imperfecta and adult osteoporosis, but other potential roles are emerging for these compounds, which have extremely potent effects on bone

CPT is a rare disorder often leading to multiple surgical procedures in an attempt to achieve union but frequently ending in amputation. The author presents a personal series of four cases (ages 3 + 4, 3 + 4, 4 + 3, 7 + 9 years) three of which had had a total of ten previous procedures. All patients underwent removal of previous fixation, excision of the abnormal periosteal tissue, freshening of the bone ends and “ram rodding” together under compression with the application of an lIizarov frame. A separate proximal osteotomy was performed for lengthening. The non-union was grafted primarily at the time of fixator application. Following frame removal a custom made telescopic nail was inserted in the three most recent cases. Average frame time was 263 days (184–301). All four cases have healed primarily and remain healed (19, 28, 31 and 70 months) post frame removal. The case not treated with a nail underwent bending of the proximal regenerate bone and required a second osteotomy to correct the deformity. Other than pin infections managed by antibiotics and local cares, the only other complication was the backing out of a cross-locking wire from the IM nail which required reinsertion. The use of the llizarov frame enables a radical excision of pathological tissue and rigid compression of the non-union with concurrent restoration of limb length. The telescoping rod that is locked in the epiphyses proximally and distally enables normal rehabilitation of the joints without the need for prolonged bracing. The ongoing success of this treatment has encouraged the author to recommend it as the primary management for established congenital pseudarthrosis of the tibia

Vascularized bone grafts (VFG) have brought great benefits in the field of reconstruction of the lower extremity. However, complications such as fracture of the grafted fibula and delayed union are sometimes seen. Not only to prevent these complications but also for stability after fracture of the grafted fibula, the Ilizarov external fixator is a very useful option. We report here the clinical results of cases treated by VFG combined with Ilizarov external fixator for reconstruction of the lower extremity. We have performed 53 vascularized fibula transfers to reconstruct lower extremities. An Ilizarov external fixator was used for the initial immobilization in 7 (2 femur, 5 tibia) and for delayed union or fracture of the grafted fibula in 2 cases of congenital pseudoarthrosis of the tibia. All patients achieved good bone reconstruction. All are able to walk without a brace except for one congenital case. The average period to achieve bony fusion was 13 months in femur cases, 6 months in adult tibia cases and 2 months in congenital cases. The average periods to walk without a brace were 14 months, 8 months and 10 months respectively. However, it took 9 months and 28 months to achieve bony union in the cases with delayed union or fracture of the grafted fibula. In the reconstruction of the lower extremities using VFG, the determining factor in method selection is whether sufficient mechanical support is available. An Ilizarov external fixator for immobilization permits the patient to walk as soon as possible. Dynamization from this semi-rigid external fixator causes bone hypertrophy and improved incorporation of the graft

Introduction and Aims: The treatment of bone defects secondary to congenital pseudoarthrosis of the tibia, infections and tumors is problematic. The vascularised fibular graft has been used for many years as a way to improve blood supply and successfully achieve union. Lengthening the limb prior to grafting can improve outcomes. Method: Forty-one patients with major bone defects secondary to tumor resections, infections and congenital pseudoarthroses had reconstruction with a vascularised fibular graft. Of these, 10 patients had limb length discrepancies, which were treated by application of an external fixater for lengthening through the bone gap. Following restoration of length with an external fixater, a vascularised fibular graft was inserted to bridge the bone defect. The external fixater was not removed until union of the graft to the host bone and initial hypertrophy occurred. Results: The 10 patients (five males and five females) were aged 2.5 to 14.5 years (mean 7.6 years). The affected bones included eight tibias, one humerus and one ulna. The limb length discrepancies ranged from three to 20cm (mean 6.44cm). The duration of lengthening prior to definitive vascularised fibular graft ranged between one to 15 weeks (mean seven weeks) in nine patients. In the patient with a discrepancy of 20cm, lengthening spanned 52 weeks. At the time of the definitive vascularised fibular graft procedure, the fixater was partially disassembled to facilitate surgery and microvascular anastomosis. The frame was then reassembled and used as the fixation device to protect the graft. The fixater was removed from seven to 24 weeks (mean 16 weeks) after definitive surgery. There were no complications during the lengthening process. However, two patients experienced non-unions, which were successfully treated by autologous bone grafts. One patient had a fracture of the vascularosed fibular graft, which healed uneventfully. Conclusion: A staged approach to reconstruction of major long bone deficiencies leads to a better outcome than insertion of vascularised fibular grafts without addressing the limb length discrepancy. In this type of procedure, the patients not only bridged their bone defect, but achieved limb length equality as well

It is generally accepted that children treated for congenital pseudarthrosis of the tibia (CPT) should be followed-up until skeletal maturity, before drawing conclusions about the efficacy of treatment. We undertook this study in order to evaluate the long-term results of treatment of CPT by excision of the pseudarthrosis, intramedullary rodding and onlay cortical bone grafting. Among a total of 46 children with CPT treated by a single surgeon during a 20-year period, 38 had been treated by this technique and 11 of these children have reached skeletal maturity. These eleven cases (nine boys and two girls) formed the basis for this study. The mean age at presentation was 3.1 years (range 0.4–7 years); the mean age at index surgery was 3.2 years (range 0.7–7 years). The mean age at follow-up was 18.4 years (range 16–21.6 years) with a mean interval between surgery and final follow-up of 15.2 years (range 12.8–17.4 years). In all 11 children bone graft was harvested from the contralateral tibial diaphysis. Rods passed from the heel were used in nine children and in two Sheffield telescopic rods were passed from the ankle into the tibia. The fibula was divided in three children to ensure that the tibial fragments were in good contact before placing the graft astride them; the fibula was not touched in the remaining eight instances. To ensure that the intramedullary rod supported the pseudarthrosis site till skeletal maturity, revision rodding was performed as needed when the tip of the rod receded into the distal third. A thermoplastic clamshell orthosis was used till skeletal maturity. At final follow-up the union at the pseudarthrosis site was deemed to be ‘sound’ only if two independent observers concurred that there was definite bony continuity of the cortices on both the anteroposterior and lateral radiographs. Deformities of the tibia and ankle and ranges of motion of the knee, ankle and subtalar joints were noted. The limb lengths were measured with scanograms. The morbidity at the bone graft donor site was recorded. The function of the ankle was assessed by applying the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hind foot Score. Primary union of the tibial pseudarthrosis was achieved in nine of 11 cases with a mean time to union of 6.1 months. Secondary union was achieved in the remaining two cases following further intervention. At final follow-up sound union of the tibial pseudarthrosis was noted in all eleven patients but persistent pseudarthrosis of the fibula was present in 10 of 11 cases. The lateral malleolus was proximally situated in six cases. Ten of eleven children underwent a total of 21 secondary operations on an average of 2.6 years (range 0.5–5.1 years) after initial union was achieved. Six re-fractures were encountered in five patients at a mean of 6.1 years after index surgery. All the re-fractures united following the single episode of intervention. The overall mean shortening at final follow-up was 2.6 cm. At final follow-up, five patients had ankle valgus greater than 10 degrees. All the 11 patients walked without pain. Only two patients had significant motion at the ankle. Despite the ankle stiffness in the remaining children the AOFAS ankle-hindfoot scores ranged between 70 and 98 (mean 83.3). Our long-term results are comparable to the results of other studies in terms of the rate of union, the re-fracture rate, limb length discrepancy, residual deformity and the frequency of surgery

Introduction: Distraction osteogenesis is a widely utilised orthopaedic procedure; however prolonged treatment time and considerable disuse osteoporosis remain problematic, with decreases of 44% to 61% in bone mineral density reported in adjacent bone. Refracture rates of 10–20% are reported after frame removal. We set out to examine the role of bisphosphonates in protecting the bone against stress-shielding related osteopaenia during distraction osteogenesis. We used a NZW rabbit model with 2 weeks distraction to 10.5 mm then 4 weeks consolidation. We achieved positive results in the initial trial using the bisphosphonate pamidronate (Novartis). Not only were we able to abolish the decrease in BMD in the surrounding bone, we noted an increase in the mineral properties and strength of the new bone. Moving on to zoledronic acid (Novartis), a third generation bisphosphonate designed for use in malignant hypercalcaemia and bone metastases, we achieved even more promising results. In a study of thirty rabbits, we gave saline to 10 controls, 0.1 mg/kg zoledronic acid to 10 rabbits at surgery and 10 further rabbits received 0.1 mg/kg zoledronic acid at surgery and at two weeks. The animals were scanned by DXA at 2, 4 and 6 weeks, and by QCT after culling. Mechanical testing was performed by destructive 4-point bend tests. Second-weekly DXA scans documented faster mineral accrual after distraction between 2 and 4 weeks in both treatment groups (ANOVA p< 0.01). In the control group, the BMD in the segments around the lengthening fell by 0.16 g/cm2 between the 2nd and 6th week. The BMD showed a net increase over the same time period in all treated animals (ANOVA p< 0.01). The cross sectional area of the regenerate at six weeks as measured by QCT was increased by 49% in the zoledronate group versus controls and by 59% in the re-dosed zoledronate group. (ANOVA p< 0.01). The final (6 week) BMC of the regenerate was increased by 92% in the zoledronate group versus controls and by 111% in the re-dosed zoledronate group (ANOVA p< 0.01). Bone mineral density was increased by a lesser but significant degree to normal values (28% and 34% respectively, ANOVA p< 0.01). Four point bend testing revealed increases in peak load of 29% in the single dose and 89% in the re-dosed group (ANOVA p< 0.01). Two patients are presented, one with congenital pseudarthrosis of the tibia, and one who had not united a distraction gap of 5 cm at six months, who were treated with pamidronate. Both showed successful responses in line with our research findings. A clinical trial is being set up to establish a scientific case for bisphosphonate use in patients undergoing distraction osteogenesis with the aim of possible earlier frame removal and less refractures. Further research in other areas of bone healing is also planned

Pathological fractures in children can occur as a result of a variety of conditions, ranging from metabolic diseases and infection to tumours. Fractures through benign and malignant bone tumours should be recognised and managed appropriately by the treating orthopaedic surgeon. The most common benign bone tumours that cause pathological fractures in children are unicameral bone cysts, aneurysmal bone cysts, non-ossifying fibromas and fibrous dysplasia. Although pathological fractures through a primary bone malignancy are rare, these should be recognised quickly in order to achieve better outcomes. A thorough history, physical examination and review of plain radiographs are crucial to determine the cause and guide treatment. In most benign cases the fracture will heal and the lesion can be addressed at the time of the fracture, or after the fracture is healed. A step-wise and multidisciplinary approach is necessary in caring for paediatric patients with malignancies. Pathological fractures do not have to be treated by amputation; these fractures can heal and limb salvage can be performed when indicated.