Femoral Lengthening in Children-A Comparison Between Magnetic Intramedullary Lengthening Nails and External Fixators.

BACKGROUND: Femoral lengthening can be achieved using external fixators or intramedullary lengthening nails. The purpose of this research was to compare the outcome of femoral lengthening in children using PRECICE magnetic lengthening nails with lengthening external fixators. METHODS: Retrospective analysis of 50 children who had femoral lengthening. Group A included patients who had lengthening with external fixation, patients in Group B had lengthening with PRECICE intramedullary lengthening nails. Each group included 25 patients. The sample strictly included children aged between 11 and 17 years. Patients in each group were matched according to age and indication for lengthening whether congenital or acquired conditions. The outcomes focused on the ability to achieve target length, healing index, residual malalignment, length of hospitalization following the osteotomy surgery, and encountered complications. RESULTS: Mean patient age was 14.7 years for each group. The length gain was 42±12 mm for Group A and 41.6±8 mm for Group B (P=0.84). Lengthening nails achieved the target length more accurately compared with external fixation (P=0.017). The healing index was significantly higher in group A with 53.2±19 days/cm compared with 40.2±14 days/cm in group B (P=0.03). Group A had significantly higher complications than group B (P<0.0001). There was no statistically significant difference in the final coronal malalignment between the 2 groups (P=0.2). The mean length of stay was 9.2±5.8 days for group A and 4.2±3.3 days for group B (P=0.0005). CONCLUSION: Magnetic lengthening nails are clinically effective for femoral lengthening in the pediatric population. Compared with external fixation, healing index and complications were more favorable with PRECICE nails. Further research is required to study the cost-effectiveness of this technique. LEVEL OF EVIDENCE: Level IV-case series.

Deformity Correction, Surgical Stabilisation and Limb Length Equalisation in Patients with Fibrous Dysplasia: A 20-year Experience.

INTRODUCTION: Fibrous dysplasia (FD) of bone can be present with pain, deformity and pathological fractures. Management is both medical and surgical. Little literature exists on the surgical management of both monostotic and polyostotic FD. We present our experience of limb reconstruction surgery in this pathological group of bone disease. MATERIALS AND METHODS: A retrospective cohort of children who underwent limb reconstruction surgery at a single high-volume paediatric centre was identified from a prospective database. Case notes and radiographs were reviewed. Surgical techniques, outcomes and difficulties were explored. RESULTS: Twenty-one patients were identified aged between 7 and 13 at presentation to the limb reconstruction unit. Eleven were female, nine had McCune-Albright syndrome, seven had polyostotic FD and five had monostotic. Proximal femoral varus procurvatum deformity was the most common site requiring surgical intervention. The distal femur, tibia, humerus and forearm were also treated.Methods include deformity correction with intramedullary fixation including endo-exo-endo techniques, elastic nailing, guided growth, circular fixator technique and fixator-assisted plating. Correction of deformity and leg length discrepancies was common.The osteotomies went on to heal with no nonunions or delayed healing. We encountered secondary deformity at distal end of nails as the children grew as expected. These were managed with revision nailing techniques and in some cases external fixation. There was one implant failure, which did not require revision surgery. CONCLUSION: The surgical management of pathological bone disease is challenging. Corrective osteotomies with intramedullary fixation can be very successful if appropriate limb reconstruction principles are adhered to. Deformity correction, guided growth and lengthening can all be successfully achieved in bone affected by FD. Polyostotic FD can be present with secondary deformities, and these can be difficult to manage. HOW TO CITE THIS ARTICLE: Hampton MJ, Weston-Simmons S, Giles SN, et al. Deformity Correction, Surgical Stabilisation and Limb Length Equalisation in Patients with Fibrous Dysplasia: A 20-year Experience. Strategies Trauma Limb Reconstr 2021;16(1):41-45.

Mechanical Analysis of Explanted Telescopic Rods in the Management of Osteogenesis Imperfecta: A Multicenter Study.

BACKGROUND: Telescopic rods in the management of osteogenesis imperfecta fail frequently. This could be attributed to technical errors, rod design, and rod structure. We aimed to analyze the mechanical properties and tribology of explanted male and female components to identify effects of in vivo telescoping that may relate to observed patterns of successful telescoping or failure. METHODS: Recruitment took place at 3 of the 4 English centers for osteogenesis imperfecta. Twenty-five rods explanted for growth or failure during revision to a new rod were analyzed in terms of clinical indication and prerevision imaging to identify if there was a technical mode of failure. Laboratory analysis was performed using optical and scanning electrical microscopy, radiograph diffraction analysis, hardness test, bending test, and energy-dispersive x-ray spectroscopy. RESULTS: All implants tested were of high-grade stainless steel. Female components had inferior strength [mean Vickers hardness property (HV0.3) at 0.3 to 313 kg] in comparison to male components (HV0.3 406) due to different techniques of manufacture. Female rods also had a higher wear coefficient (7.89×10-12 m3/N/m3) than the male rods (6.46×10-12 m3/N/m3). Abrasive wear, shear deformation, scratches, and wear debris were identified in all rods. Male and female components displayed corrosion contributing to adhesive wear. Intraoperatively cut rods, particularly the female components, had irregular ends leading to more wear. CONCLUSIONS: Current manufacturing techniques result in inferior material strength in female components compared with males, which combined with wear patterns is likely to lead to implant failure. Intraoperative cutting of rods may increase risk of failure due to wear. Considering techniques to improve strength as well as design in new implants may lead to better outcomes. LEVELS OF EVIDENCE: Level IV-cross-sectional study.

Correction of Bowleg Deformity in Achondroplasia through Combined Bony Realignment and Lateral Collateral Ligament Tightening.

INTRODUCTION: Achondroplasia is one of the most common osteochondrodysplasias with an incidence of 1 in 26,000 live births. Bowing of lower limbs can cause significant morbidity in this population. The use of the Ilizarov external fixator to tighten collateral ligaments of the knee in children has not been reported in the literature. We report the technique and early results of lateral collateral ligament (LCL) tightening with correction of genu varum in children with achondroplasia. MATERIALS AND METHODS: A retrospective review of children with achondroplasia presenting with bowleg deformity who were treated by corrective osteotomy and LCL tightening was conducted. Between 1998 and 2003, 12 patients (24 limb segments) underwent this procedure and were included in the study. All patients had grade III LCL laxity preoperatively. Pre- and postoperative anteroposterior standing mechanical axis radiographs were evaluated. The final outcome was graded using the grading system of Paley et al. RESULTS: All patients had bilateral corrections. The Ilizarov external fixator was used in 10 patients and the Orthofix limb reconstruction system in 2 patients. The bony realignment was achieved through monofocal or bifocal tibial osteotomies. The LCL was tightened in all limb segments using the Paley's type II strategy. The final result was graded as excellent in 20 limb segments and good in 4 limb segments. One patient developed transient common peroneal nerve palsy, four developed grade II pin site infections, and there was premature consolidation of the tibial regenerate in one patient. HOW TO CITE THIS ARTICLE: Kurian BT, Belthur MV, Jones S, et al. Correction of Bowleg Deformity in Achondroplasia through Combined Bony Realignment and Lateral Collateral Ligament Tightening. Strategies Trauma Limb Reconstr 2019;14(3):132-138.