Foot Deformity Correction with Hexapod External Fixator, the Ortho-SUV Frame™

External fixators enable distraction osteogenesis and gradual foot deformity corrections. Hexapod fixators have become more popular than the Ilizarov apparatus. The Ortho-SUV Frame™ (OSF; Ortho-SUV Ltd, St. Petersburg, Russia), a hexapod that was developed in 2006, allows flexible joint attachment such that multiple assemblies are available. We assessed the reduction capability of several assemblies. An artificial bone model with a 270-mm-long longitudinal foot was used. A 130-mm tibial full ring was attached 60 mm proximal to the ankle joint. A 140-mm, two-third ring forefoot was attached perpendicular to the metatarsal bone axis. A 130-mm, two-third ring hindfoot was attached parallel to the tibial ring. A V-osteotomy, which was combined with 2 oblique osteotomies at the navicular-cuboid bone and the calcaneus, was performed. The middle part of the foot, including the talus, was connected to the tibial ring. We assessed 5 types of forefoot applications and 4 types of hindfoot applications. The range of correction included flexion/extension in the sagittal plane, adduction/abduction in the horizontal plane, and pronation/supination in the coronal plane. Additionally, we reported the short-term results in 9 clinical cases. The forefoot applications in which the axis of the hexapod was parallel to the axis of the metatarsal bones had good results, with 52°/76° for flexion/extension, 48°/53° for adduction/abduction, and 43°/51° for pronation/supination. The hindfoot applications in which the hexapod encircled the ankle joint also had good results, with corresponding values of 47°/58°, 20°/35°, and 28°/31°. Clinically, all deformities were corrected as planned. Thus, multiple assemblies and a wide range of corrections are available with the OSF. © 2013 American College of Foot and Ankle Surgeons

Relationships between reference lines altered during leg shape correction as requested by the patient

shaped legs as classified by A. A. Artemiev. The purpose of the study was to compare changes in the relationship between reference lines as mechanical axis deviation (MAD), mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal tibial angle (mLDTA) and the associated duration of the correction (CP), fixation (FP) and frame-on periods (FoP) in patients who underwent correction to have the legs shape as requested and those who underwent tibial deformity correction. Material and methods There were 43 patients (84 segments operated on) in the cosmesis group and 15 participants (28 segments operated on) in orthopedic group. Preperative MAD, mMPTA, mLDTA measured 17.48 ± 1.14 mm medially, 84.90 ± 0.35° and 90.61 ± 0.39° in the cosmesis patients; 19.18 ± 2.86 mm medially, 84.04 ± 0.35°, 89.09 ± 0.37° in orthopaedic patients with no statistically significant differences observed between the groups. Results CP, FP and FoP lasted for 41.93 ± 3.96, 97.67 ± 7.78 and 139.60 ± 5.15 days in the cosmesis group, and 18.22 ± 3.05, 134.89 ± 9.42 and 153.00 ± 8.49 in controls. FP/CP, CP/FoP, FP/FoP measured 0.57 ≈ 1/2, 0.31 ≈ 1/3, 0.69 ≈ 2/3 in the cosmesis group and 0.15 ≈ 1/7; 0.12 ≈ 1/8; 0.88 ≈ 7/8 in controls. MAD, mMPTA, mLDTA measured 6.08 ± 0.87 mm laterally, 90.80 ± 0.31°, 88.62 ± 0.35° in the cosmesis participants, and 0.61 ± 0.82 mm laterally, 89.46 ± 0.54°, 87.68 ± 0. 63° in controls. Discussion There were no statistically significant differences in FoP with different duration of CP (≈ 1/3 FoP for the cosmesis group and ≈ 1/8 FoP for controls). The means of MAD, mMPTA of measured up to tibial valgus in cosmesis patients and were well within acceptable limits of normal in controls.Tibial valgus was caused by too much overcorrection (by ¼ on average)

Spring technique for correction of multilevel deformity using hexapod external fixator

Context: Osteotomies in several parts of one long bone are recommended for correction of a long, curved, and wide-angled deformity. Hexapod external fixators (HEFs) allow for the single-stage correction of multiplanar deformity, but they are heavy, expensive, and requires continuous management of 12 struts, if at more than one level. Aims: We proposed the use of springs with HEF to support the intermediate ring. Deformity between the proximal and distal rings is corrected using one HEF, and the intermediate fragment is automatically corrected by the tension of the springs. Settings and Design: This was a retrospective descriptive study. Subjects and Methods: We treated seven males and eight females with 17 affected limbs. Four patients with familial hypophosphatemic rickets, five posttraumatic deformities, two osteogenesis imperfectas, three fibrous dysplasias, and one neurofibromatosis were included. The mean preoperative angle between the most proximal and distal fragments was 62.5°. First, small distraction at each level was initiated with one HEF fixed to the most proximal and distal rings, and Ilizarov hinges applied between the proximal and intermediate rings. Then, a set of three springs was applied for each interval between the rings. Gradual correction using HEF was performed, considering only the axes of the proximal and distal bone fragments. Results: Good alignment was achieved in all patients without severe complications. The mean correction period was 5.5 weeks and mean fixation period was 33.8 weeks. Conclusion: Combination of HEF and springs is capable of correcting severe deformity

Determination of the Maximal Corrective Ability and Optimal Placement of the Ortho-SUV Frame for Femoral Deformity with respect to the Soft Tissue Envelope, a Biomechanical Modelling Study

Circular fixation according to the Ilizarov method is a well-recognised modality of treatment for trauma and deformity. One shortcoming of the traditional fixator is its limited ability to correct more than one plane of deformity simultaneously, leading to lengthy frame-time indices. Hexapod circular fixation utilising computer guidance is commonplace for complex multidimensional deformity but difficulties often arise with correction of femoral deformity due to bulkiness of the frame construct, particularly in proximal deformity and in patients of increased size. The Ortho-SUV frame is an innovative hexapod which permits unique customisation to individual patient anatomy to maximise tolerance and optimal range of deformity correction. We hypothesised that the optimal configuration and maximal degree of correction achievable by the Ortho-SUV frame can be biomechanically modelled and applied clinically. A study was constructed using Ortho-SUV and femoral limb models to measure deformity correction via differing frame constructs and determine optimal frame configuration to achieve correction in proximal, middle, and distal third deformities with respect to the soft tissue envelope. The ideal frame configuration is determined for correction of deformity in all locations of the femur with the maximal parameters of correction calculated whilst avoiding and mitigating soft tissue irritation from bulky frame construction

Advances in modern osteotomies around the knee

Abstract Corrective lower limb osteotomies are innovative and efficient therapeutic procedures for restoring axial alignment and managing unicompartmental knee osteoarthritis. This review presents critical insights into the up-dated clinical knowledge on osteotomies for complex posttraumatic or congenital lower limb deformities with a focus on high tibial osteotomies, including a comprehensive overview of basic principles of osteotomy planning, biomechanical considerations of different implants for osteotomies and insights in specific bone deformity correction techniques. Emphasis is placed on complex cases of lower limb osteotomies associated with ligament and multiaxial instability including pediatric cases, computer-assisted navigation, external fixation for long bone deformity correction and return to sport after such osteotomies. Altogether, these advances in the experimental and clinical knowledge of complex lower limb osteotomies allow generating improved, adapted therapeutic regimens to treat congenital and acquired lower limb deformities