Limb lengthening and deformity correction with fully implantable systems is becoming more and more widespread. Different actuation techniques are known and every system has its specific limitations in distraction control and/or stability. A new system with magnetic actuation offers outstanding options. The mechanism of the Phenix M2(®) bone lengthening nail (Phenix Medical, France) is driven by a strong external magnet. The device can provide lengthening, shortening and bone transport. Between December 2011 and November 2012 we applied the nail in 10 patients with an average age of 25 years (range 15-40 years). There were 6 femoral and 4 tibial procedures. The intended distraction goal was achieved in 8 of 10 patients. In three cases we simultaneously corrected malalignment. Average lengthening was 4.6 cm (range 1.3-7.6 cm). Average distraction index was 0.85 mm/day (range 0.6-1.3mm/day). Average weight bearing index was 27 days/cm (range 16-37 days/cm). Three patients had revisions due to early distraction arrest. The early results are comparable to those of other intramedullary systems in the literature like the ISKD(®), the Albizzia(®) or the Fitbone(®) system. All intramedullary procedures require accurate analysis and planning, advanced operative technique and close follow-up. The custom made design of the Phenix nail with unique options for size, stroke and locking provides new options for small bones and improved stability. The shortening option may be helpful for soft tissue problems, joint subluxation and additional stimulation of bone formation. Magnetic forces have to be considered and too much soft tissue around the nail might be a limiting factor. The magnetically actuated Phenix nail offers new therapeutic options in limb lengthening.

Limb lengthening with fully implantable magnetically actuated mechanical nails (PHENIX(®))-preliminary results.

Background In many countries around the world, football (association football, or "soccer" predominantly in North America) is the sport most commonly played by children and adolescents. It is widely thought that football players are more likely to develop genu varum (bowlegs); an association with knee arthritis also seems likely. The goals of this systematic review and meta-analysis are to provide an overview of the available evidence on genu varum after intensive soccer training in childhood and adolescence, and to discuss the possible pathogenetic mechanisms. Methods We systematically searched the PubMed, Medline, Embase, and Coch- rane Library databases for studies of the relation between leg axis development and intensive football playing during the growing years. Results Controlled studies employing the intercondylar distance (ICD) as the target variable were evaluated in a meta-analysis, with the mean difference as a measure of effect strength. This meta-analysis included 3 studies with a total of 1344 football players and 1277 control individuals. All three studies individually showed a signifi- cant difference in the mean ICD values of the two groups. The pooled effect esti- mator for the mean difference was 1.50 cm (95% confidence interval [0.53; 2.46]). Two further studies that could not be included in the meta-analysis had similar con- clusions. Asymmetrical, varus muscle forces and predominantly varus stress on the osseous growth plates neighboring the knee joint, especially during the prepubertal growth spurt, seem to be the cause of this phenomenon. Conclusion Intensive soccer playing during the growing years can promote the devel- opment of bowlegs (genu varum) and, in turn, increase the risk of knee arthritis. Phy- sicians should inform young athletes and their parents of this if asked to advise about the choice of soccer as a sport for intensive training. It cannot be concluded, however, that football predisposes to bowlegs when played merely as a leisure activity.

Bowlegs and Intensive Football Training in Children and Adolescents.

Limb lengthening and deformity correction using fully implantable nails have gained increasing acceptance. The nails used in these procedures are either straight or have an acute proximal angle such that they differ from standard trauma nails, which have sagittal radius of curvature. Use of straight

Surgical Techniques for Lengthening and Deformity Correction of the Tibia With Lengthening Nails

Neck-shaft angle (NSA) and medial proximal femoral angle (MPFA) describe the geometry of the proximal femur, but they are influenced by rotation. The MPFA is closer to the right angle and therefore assumed to be less influenced. This hypothesis was tested with a mathematical approach to compare the effects of rotation and their clinical relevance on both angles. We developed a three-dimensional (3D) geometrical model representing projectional radiography of the femoral axes under rotation and derived a mathematical equation. For validation purposes, we experimentally simulated projectional radiography and compared the results to those of the equation (five different inclinations of the femoral neck (IFN) each in 13 different rotations). The validated equation was used to determine the influence of rotation (–60° to +60°) on normal valued NSA and MPFA. The mean absolute difference between calculated and experimentally measured values was 0.6° (standard deviation [SD] 0.5; 0.0–2.2). The mean calculated difference between true and projected NSA was 7.1° (SD 7.1; 0.0–22.0), and for the MPFA, it was –1.9° (SD 2.2; –7.4 to 0.0). Clinically relevant deviations (≥5°) occurred at ≥30° external or ≥ 40° internal rotation for the NSA, for the MPFA at 60° external rotation. Mathematical modeling of radiographic projection of the IFN is possible to a high level of accuracy. Our results indicate that the NSA is significantly more susceptible to deviations caused by rotation than the MPFA. Clinicians must be aware of rotational influences in radiographic projection and possibly should use the MPFA instead of the NSA. The rotational influence during X-ray imaging must be controlled accurately, and femoral torsion should be quantified in computed tomography/magnetic resonance imaging (CT/MRI) scans if possible. 3-D bone models reconstructed from digital image data can be a future option for measuring true angles. Level of evidence was basic research.

Medial Proximal Femoral Angle better than Neck-Shaft Angle? Influence of Rotation on the Anteroposterior Radiograph

A teenage boy presented with a post-traumatic leg length discrepancy (LLD) of 7 cm with bifocal femoral deformity, impairment of soft tissue and a long, segmental defect of the superficial femoral artery. Limb lengthening and deformity correction was performed in a two-staged project. After partial consolidation of a bifocal osteotomy and realigment with a customized, straight tibial nail, lengthening was then performed with a custom-made, magnetic-driven lengthening nail (MDLN/ Phenix) in the second step. In the latter part of the distraction period, a vascular impairment occurred. It could be solved uneventfully by controlled, minor backtracking of the MDLN and subsequent reduction of the distraction rate. This caused a low distraction index of 0.68 mm/day. Nevertheless, bone formation was excellent with early weight-bearing (weight-bearing index: 16.2 days/cm). The main issues for the successful treatment of this case of LLD and bifocal deformity with soft tissue and vascular impairment were meticulous analysis and planning (End point first planning method – EPF), a staged procedure to reduce risks, and a custom-made MDLN with the option of non-invasive controlled shortening. 1 Brief Clinical History The 13-year-old was rolled over by a car at the age of 7. He suffered a severe soft tissue, vascular and bone defect of the right femur. After successful limb salvage, he experienced some unsuccessful attemps of reconstruction. He presented with a post-traumatic leg length discrepancy (LLD) of 7 cm with bifocal femoral deformity, impairment of soft tissue and a long, segmental defect of the superficial femoral artery. Due to a condylar deformity, knee joint flexion was reduced to 10–90 with no instability. The boy was provided with a cochlea implant due to a sensorineural hearing loss in early childhood when he was 3. 2 Preoperative Clinical Photos and Radiographs See Figs. 1, 2, 3, and 4. *Email: peter.thaller@med.uni-muenchen.de Limb Lengthening and Reconstruction Surgery Case Atlas DOI 10.1007/978-3-319-02767-8_293-1 # Springer International Publishing Switzerland 2014

https://link-springer-com-443.webvpn.jmu.edu.cn/content/pdf/10.1007%2F978-3-319-02767-8_293-1.pdf

Malaligned and Short Femur Associated with Vascular Deficit: Two-Stage Realignment and Lengthening with Custom-Made Magnetic-Driven Intramedullary Nail

The gold standard for radiographic assessment and correction planning of lower limb deformities is the long standing radiograph (LSR). Additional computer tomography (CT) can measure exact length and torsion. For correct positioning in LSR the patella should be centered on the femoral condyles (knee forward position—KFP). The flexion extension axis of the knee (KFEA) is mainly defined by the shape of the femoral condyles represented by their dorsal tangent. In 30 CT scans the position of the patella and its relation to the dorsal tangent to the femoral condyles were retrospectively analyzed. With a custom-made positioning apparatus to control the leg rotation and load exactly for each limb separately we analyzed 38 CT scans. 20 digital LRS were retrospectively compared with the correlating CT-data. In CT scans with KFP the KFEA differed 11° from the frontal plane ( p p

Digital imaging in lower limb bone deformities—standards and new perspectives

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Digital imaging in lower limb bone deformities—standards and new perspectives