Search Results (8)

This study focuses on the development and evaluation of the OrthoNail hybrid intramedullary implant for lower limb lengthening in patients requiring significant skeletal reconstruction. The implant addresses the challenges in load-bearing during rehabilitation, providing a robust solution that is capable of supporting physiological loads. Mechanical tests, including axial compression, tension, torsion, and 3,4-point bending, determined the implant’s load capacity and fatigue resistance, while finite element analysis assessed stress distributions in bone tissue and around screw holes during single-leg stance, with boundary conditions derived from Orthoload database data. The OrthoNail implant demonstrated excellent mechanical stability, sustaining torsional loads of up to 19.36 Nm at maximum elongation (80 mm) and 17.16 Nm at zero elongation. Under axial compression, it withstood forces of up to 1400 N, maintaining structural integrity. Fatigue testing revealed resilience under dynamic loading conditions for over 1,000,000 cycles at a load of 500 N, with no mechanical failure or material degradation observed. Stress concentrations near screw holes indicate areas for potential optimization. The findings indicate that the OrthoNail implant demonstrates excellent mechanical stability and is well-suited for clinical application, enabling early full weight-bearing during rehabilitation. Full article

Background: Fibrous dysplasia (FD) is a rare condition in which normal spongy and cortical bone is replaced by non-neoplastic fibrous tissue, leading to weakened bone matrix and increased risk of pathological fractures and deformities. Treating these deformities poses a significant challenge for surgeons. While various cases of surgical stabilization and limb lengthening using intramedullary nails have been reported, there is limited evidence on the use of Motorized Intramedullary Limb-Lengthening Nails (MILLNs) in FD patients. This case report presents the clinical history of a patient with FD who underwent multiple surgical interventions to address severe lower limb length discrepancy (LLD) and angular deformity caused by multiple fractures. Case presentation: A sixteen-year-old Caucasian girl with polyostotic FD developed a severe post-traumatic LLD of 10 cm on the right side, associated with coxa vara, valgus knee, and patellar instability. The deformity of the proximal femur was addressed with a valgus and derotational femoral osteotomy. However, this procedure exacerbated the knee’s valgus deformity and only partially corrected the LLD, leading to the decision to proceed with femoral lengthening. A retrograde magnetic intramedullary nail (PRECICE, NuVasive) was utilized for this purpose. Approximately three months postoperatively, radiographs revealed the loosening of the proximal anchoring screw, while the nail had reached maximum distraction. We then proposed reactivating the previously implanted nail. Nine months after the final surgery, standing long-leg radiographs showed a residual shortening of 1 cm, with excellent healing at the fracture sites and the nail and screws remaining securely in place. The patient was monitored regularly, with the latest follow-up occurring four years and five months after the conclusion of the last lengthening procedure. Conclusions: This case report describes the reactivation of a MILLN in a patient with polyostotic fibrous dysplasia. While nail reactivation has been previously described in the literature, to our knowledge, it has not been reported for treating complications arising from FD. In cases of mechanical complications, this approach can equalize leg length discrepancies and correct deformities, avoiding additional invasive surgeries and reducing healthcare costs. As this is an off-label treatment, preoperative consent from both the patient and the parents is required. Full article

This comprehensive study presents a pioneering approach to limb lengthening, leveraging the advancements in wireless technology to enhance orthopedic healthcare. Historically, limb lengthening has been a response to discrepancies caused by fractures, diseases, or congenital defects, utilizing the body’s innate ability to regenerate bone and surrounding tissues. Traditionally, this involved external or internal fixation devices, such as the Ilizarov and Taylor Spatial frames or the Precice nail and Fitbone. The focal point of this research is the development and testing of a wireless intramedullary nail implant prototype, controlled remotely via a mobile application. This implant comprises a microcontroller, Bluetooth Low Energy module, a brushed DC motor controlled through an H-bridge, and a force sensor, all powered by medical-grade batteries. The integration of wireless technology facilitates patient autonomy in managing limb lengthening, reducing the need for frequent clinical visits. The methodology involves a detailed block diagram for our proposed work, outlining the process from treatment planning to the initiation of limb lengthening via the mobile application. Osteogenesis, the formation of new bone tissue, plays a crucial role in this procedure, which includes pre-surgery assessment, osteotomy, latency, distraction, consolidation, and removal phases. Key challenges addressed include custom battery design for efficient operation, size constraints, and overcoming signal interference due to the Faraday cage effect. Attenuation testing, simulating human tissue interaction, validates the implant’s connectivity. In conclusion, this research marks a significant stride in orthopedic care, demonstrating the feasibility of a wireless implant for limb lengthening. It highlights the potential benefits of reduced clinical visits, cost efficiency, and patient convenience. Despite limitations such as battery requirements and signal interference, this study opens avenues for future enhancements in patient-centered orthopedic treatments, signaling a transformative shift in managing limb length discrepancies. Full article

Leg length discrepancies (LLD) are frequently associated with coronal malalignment. Temporary hemiepiphysiodesis (HED) is a well-established procedure for the correction of limb malalignment in skeletally immature patients. For treatment of LLD > 2 cm, lengthening with intramedullary devices gains increasing popularity. However, no studies have investigated the combined application of HED and intramedullary lengthening in skeletally immature patients. This retrospective single-center study evaluated the clinical and radiological outcomes of femoral lengthening with an antegrade intramedullary lengthening nail combined with temporary HED performed in 25 patients (14 females) between 2014 and 2019. Temporary HED through the implantation of flexible staples of the distal femur and/or proximal tibia was either performed prior (n = 11), simultaneously (n = 10) or subsequently (n = 4) to femoral lengthening. The mean follow-up period was 3.7 years (±1.4). The median initial LLD was 39.0 mm (35.0–45.0). Twenty-one patients (84%) presented valgus and four (16%) showed varus malalignment. Leg length equalization was achieved in 13 of the skeletally mature patients (62%). The median LLD of the eight patients with residual LLD > 10 mm at skeletal maturity was 15.5 mm (12.8–21.8). Limb realignment was observed in nine of seventeen skeletally mature patients (53%) in the valgus group, and in one of four patients (25%) in the varus group. Combining antegrade femoral lengthening and temporary HED is a viable option to correct LLD and coronal limb malalignment in skeletally immature patients; however, achieving limb length equalization and realignment may be difficult in cases of severe LLD and angular deformity, in particular. Full article

Leg Length Discrepancy (LLD) is a critical problem which not only impacts the quality of life but also causes other physical ailments such as limping and severe back pain. Most people had a non-negligible difference in the length of their two legs, and 0.1% of the population with differences of 20 mm or more are diagnosed as a difference in limb length. The Ilizarov external fixator is commonly used in treating LLD as conventional therapeutic equipment, but often causes serious complications that cannot be prevented. Therefore, intramedullary leg-lengthening treatment has become popular in distraction osteogenesis to eliminate extracorporeal surgery. This paper presents a study on the design and optimization of a novel electromagnetic-driven Intramedullary Skeletal Distraction Robot (ISDR) with robust mechanical stiffness and surplus electromagnetic driving force. Compared with PRECICE, the split structure of ISDR eases the optimal design and manufacturing difficulties to strengthen mechanical stiffness, and the electromagnetic configuration allows improving the distraction force by adjusting the Permanent Magnet Brushless Direct Current (PMBLDC) motor parameters. ISDR, which is implanted in the medullary cavity, has the Von-Mises stress of 952.15 MPa, and the first mode of natural frequency is 28.823 Hz indicating that it can withstand the load during the walking gait phases. On the other hand, the ISDR distraction force encounters resistance from muscle fibers, and an average driving torque of 9 Nmm ensures its distraction. Based on the results, ISDR is proven secure and reliable during and after leg-lengthening treatment, which can significantly reduce lifestyle disruption and medical complications. Full article

Concerns surrounding osteolysis near and around the modular junction of a stainless-steel intramedullary lengthening rod prompted a manufacturer recall from the United States market in early 2021. These actions were preceded by similar steps taken in Europe. A concomitant review of stainless-steel lengthenings at our institution demonstrated signs of adverse tissue reaction including periosteal reaction and osteolysis at the modular junction and/or male-sided locking screws. Nearly half of our patients presented with these findings on radiographic images. At the time of the previous review, only half of the nearly 60 implanted stainless-steel devices met a 6-month follow-up. At this juncture, many patients have had their devices explanted. Given the suspected adverse tissue reactions caused by a component of the internal device, we sought to examine the rate of osteolysis post-explantation following removal of a stainless-steel nail. We reviewed a consecutive series of patients who underwent implantation of a stainless-steel limb lengthening device in the femur and/or tibia at a single institution between December 2018 and December 2020. Patients were included if their device was explanted. Periosteal reaction and osteolysis was classified according to a novel and validated classification system, as analyzed by five fellowship-trained surgeons. In addition, changes observed prior to explantation were tracked post-explantation to assess for resolution. The incidence of periosteal reaction and osteolysis prior to explantation was 22/57 (39%) and 15/57 (26%), respectively. Of the 15 patients with osteolysis pre-explantation, 14 patients’ implants were explanted. Of these, eight patients had available follow-up films. Two patients were identified as having partial osteolysis resolution at mean 1-year follow-up, while six patients were identified as having complete osteolysis at mean 18-months follow-up. Periosteal tissue reaction and osteolysis largely resolved following explantation in a subset of patients. These results provide further support to the claim that the stainless-steel device contributed to the changes seen. Further follow-up is warranted to examine the longer-term effects of adverse tissue reaction in this patient population. Full article

There are multiple forms of enchondromatosis with Ollier’s and Maffucci’s being the most prevalent types. Limb length discrepancy is a common problem in patients with Ollier’s and Maffucci’s enchondromatosis. There are multiple reports about lengthening bones in patients with enchondromatosis using external fixators. However, there are no case series regarding the use of implantable lengthening technology. The purpose of this paper is to describe our experience with implantable nail lengthening in patients with enchondromatosis. A retrospective chart and radiographic review of patients with enchondromatosis who underwent implantable nail limb lengthening was performed. Seven patients with 14 bony segments were reviewed. A total of 11/14 lengthenings were completed without difficulty. There were no issues in terms of fixation location in patients with Ollier’s disease. One patient with Maffucci’s syndrome experienced migration of the nail during two lengthenings due to a combination of intralesional fixation and preconsolidation. One patient with Ollier’s disease developed a knee extension contracture requiring manipulation under anesthesia. No other complications were recorded. The use of implantable nail lengthening to resolve limb length discrepancies in patients with Ollier’s disease appears to be safe and effective. Full article

Intramedullary lengthening, in cases of extensive humeral shortening, offers the advantages of preventing external-fixator-associated problems. The humeral cavity, as the main parameter in nailing, however, has been neglected in recent literature. It was hypothesized that available implants might be too large and therefore increase the risk of intraoperative fractures. The aim of this cross-sectional study was to describe the humeral canal and how it might affect the choice of implant and the surgical approach. Thirty humeri (15 female, 15 male) from clinical patients and anatomical specimens were studied. Specifically, the medullary cavity width (MCW), cortical thickness (CoT), and the course of the medullary canal were examined. The smallest MCW diameters were found at the distal third of the humeral shaft with mean diameters of 10.15 ± 1.96 mm. CoTs of female humeri were significantly smaller than those of male humeri (p < 0.001). The mean angles of the pro- and recurvatum were 4.01 ± 1.68° and 10.03 ± 2.25°, and the mean valgus bending was 3.37 ± 1.58°. Before implanting a straight lengthening nail into a doubly curved humerus, X-rays and, in selected cases, CT-scans should be performed. The unique size and course of the humeral canal favors an antegrade approach in cases of intramedullary lengthening. Full article