Precice Nail Research Articles

PRECICE nail bending in femur lengthening

IntroIntramedullary nails (ILNs) are commonly used in orthopedic surgery for the fixation of long bone fractures and limb lengthening. Understanding the structural mechanics (i.e. nail bend) of an ILN device is crucial in determining its performance under various loading conditions. Furthermore, nail diameter was found to play a key role in an ILN's susceptibility to plastic deformity. This study aims to investigate the degree of nail bending and incidence of plastic deformity in patients receiving antegrade femoral ILNs (PRECICE, NuVasive, Inc.). MethodsRetrospectively evaluated 130 ILNs (PRECICE, NuVasive, Inc.) in 100 adult patients who underwent limb lengthening done in a single center. Patients who had concomitant osteotomies, tibial lengthening, malunion, non-union, mechanical failure, or revision surgery for any reason were excluded. All nails were inserted through the greater trochanter or piriformis. Patients’ age, weight, height, and body mass index (BMI)were extracted. Radiologic assessments involved analyzing long lower limb standing X-rays before, during, and at consolidation for total distraction and nail bend. Naildiameter and patient characteristics were directly sourced from medical records. ResultsNail bend at consolidation averaged 2.4° (SD 2.4), ranging from 0 to 9. Additionally, total femoral lengthening was assessed, with a mean value of 5.3 cm (SD 2.1). A significant positive association was observed in the nail bend and weight (weight in kg/nail diameter in mm) coefficient (P < 00.01). Bilateral limb lengthening was also correlated to increase nail bend (P < 00.05). ConclusionPatient's weight to nail diameter ratio and bilateral limb lengthening were found to be significant factors affecting nail bend. These findings advance our understanding of the interrelation between the nail biomechanical profile and the patient's physical attributes, offering important implications for limb lengthening. Level of evidenceIII.

THE FITBONE INTRAMEDULLARY LENGTHENING NAIL IN THE MANAGEMENT OF ADULT AND PAEDIATRIC LIMB DEFORMITY: A RETROSPECTIVE COHORT STUDY AT A TERTIARY REFERRAL LIMB RECONSTRUCTION SERVICE

IntroductionManagement of deformity involving limb length discrepancy (LLD) using intramedullary devices offers significant benefits to both patients and clinicians over traditional external fixation. Following the withdrawal of the PRECICE nail, the Fitbone became the primary implant available for intramedullary lengthening and deformity correction within our service. This consecutive series illustrates the advantages and complications associated with the use of this device, and describes a novel technique modification for antegrade intramedullary lengthening nails.Materials &amp; MethodsA retrospective cohort review was performed of patient outcomes after treatment with the Fitbone nail at two tertiary referral limb reconstruction services (one adult, one paediatric) between January 2021 to December 2023. Aetiology, indications, initial and final LLD, use of concomitant rail assisted deformity correction (ORDER), removal time and healing index were assessed. Complications of treatment were evaluated and described in detail, alongside technique modifications to reduce the rate of these complications.Results21 nails (18 femoral, 2 tibial, 1 humeral) were inserted in 6 adult and 13 paediatric patients. Post-traumatic and congenital/developmental LLD were the most common indications for surgery in the adult and paediatric cohorts respectively. ORDER was employed in 11 cases (9 femurs and 2 tibias). Treatment goals were achieved in all but one case. Complications included superficial infection, locking bolt migration, periprosthetic fracture and component failure. Seven patients required unplanned returns to theatre.ConclusionsThe Fitbone nail is an established option for intramedullary limb lengthening, however its use in the UK has been relatively limited compared to the PRECICE until 2021. Our data helps to define its place for limb lengthening and complex deformity correction in both adult and paediatric patients, including in humeral lengthening and retrograde femoral insertion across an open physis. We have identified important potential risks and novel techniques to simplify surgery and avoid complications.

Design and Testing of an Intramedullary Nail Implant Enhanced with Active Feedback and Wireless Connectivity for Precise Limb Lengthening

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.

PRECICE nail for the management of posttraumatic bone defects with nonunion or malunion: Experience from a Latin American center

BackgroundTo evaluate the clinical outcomes using the PRECICE magnetic limb lengthening intramedullary nail for the correction of lower limb length discrepancies (LLD) in adults with posttraumatic nonunion or malunion defects in a Latin American center. MethodsA retrospective review of 25 adult patients with LLD associated with posttraumatic nonunion or malunion defects of femur or tibia treated with the PRECICE nail between January 2018 and December 2020. The primary outcomes considered were lengthening length achieved in mm, incidence of complications and quality of life (EQ-5D-3 L questionnaire). ResultsTwenty-five cases (20 femoral and 5 tibial nails) were performed, with a median follow-up of 27 months (Interquartile range-IQR: 17.5 to 34.5). The average age was 36.5 ± 12.9 years; 10 cases were women. Fifteen cases had an LLD secondary to a malunion defect and 10 cases had an LLD secondary to a nonunion. PRECICE nails were inserted for the treatment of a median LLD of 40.0 mm (IQR: 30.2 to 74.2) in the femur and 30.0 mm (28.5 to 50.0) in the tibia. An accuracy of 100% was reported in 18 cases (Femur: 14 and tibia: 4) and consolidation was achieved in 22/25 cases with the PRECICE nail in situ. Complications were recorded in 9 (36%) cases (6/20 femur, 3/5 tibia), mainly related to the consolidation process (5/9). The median EQ-5D and EQ-VAS were 0.79 (IQR: 0.63 to 0.79) and 80.0 (IQR: 50.0 to 90.0), respectively. ConclusionsThe results of this study demonstrated that the PRECICE nail is an effective device for the management of posttraumatic LLD during the treatment of nonunion or malunion bone defects of femur and tibia, offering a reasonable quality of life, despite its postoperative complication risk.

IS METALLOSIS AN ISSUE IN INTERNAL LENGTHENING?

IntroductionThere is no doubt that the future of limb lengthening lies with internal lengthening. Complication rates are reduced and patient satisfaction is increased. The evolution of internal lengthening peaked with the dual direction, easily inserted and externally controlled PRECICE Nail. It has excelled in performance in accuracy and satisfaction. Its versatility increased with smaller sizes and increased excursion. A field safety notice was issued was issued in October 2021 by the parent company NuVasive. The advice was monitoring of current cases and a hold on implantation until after a review of process. At the National Orthopaedic Hospital Cappagh we elected to remove all implanted nails and assess the nail integrity and physiological changes associated with implantation.Materials &amp; MethodsAll patients in who a retained Precice nail at the time of the field safety notice were identified. Patients and families were contacted to explain the issued safety notice from the company and explain that we would be scheduling them for nail removal. This was part of our standard care but we prioritised this group on our waiting list. Consent was obtained for nail removal but also for histological assessment of canal scrapings, blood ion level analysis and independent assessment of the retrieved nail by our academic collaborators at University College Dublin. Ion levels were then repeated at an interval post removal with consent.ResultsWe identified 7 Precice nails in 5 patients still implanted. All patients had consolidated after lengthening and were ready for nail removal. Elevated Titanium blood ion levels were identified at the time of retrieval. Histological abnormalities consistent with metalosis were identified. In all cases the nail was grossly intact and examination of the motor showed no evidence of wear or failure. Follow up ion levels obtained post retrieval showed persistent elevation.ConclusionsOur retrieval audit shows persistent elevation of Titanium ion levels and abnormal histology despite apparent nail integrity. These findings require further evaluation in a larger retrieval series to determine if there is a high incidence of this phenomenon and if ion levels have a clinical effect.

A clinical and radiological matched-pair analysis of patients treated with the PRECICE and STRYDE magnetically driven motorized intramedullary lengthening nails.

Distraction osteogenesis with intramedullary lengthening devices has undergone rapid development in the past decade with implant enhancement. In this first single-centre matched-pair analysis we focus on the comparison of treatment with the PRECICE and STRYDE intramedullary lengthening devices and aim to clarify any clinical and radiological differences. A single-centre 2:1 matched-pair retrospective analysis of 42 patients treated with the STRYDE and 82 patients treated with the PRECICE nail between May 2013 and November 2020 was conducted. Clinical and lengthening parameters were compared while focusing radiological assessment on osseous alterations related to the nail's telescopic junction and locking bolts at four different stages. Osteolysis next to the telescopic junction was observed in 31/48 segments (65%) lengthened with the STRYDE nail before implant removal compared to 1/91 segment (1%) in the PRECICE cohort. In the STRYDE cohort, osteolysis initially increased, but decreased or resolved in almost all lengthened segments (86%) after implant removal. Implant failure was observed in 9/48 STRYDE (19%) and in 8/92 PRECICE nails (9%). Breakage of the distal locking bolts was found in 5/48 STRYDE nails (10%) compared to none in the PRECICE cohort. Treatment-associated pain was generally recorded as mild and found in 30/48 patients (63%) and 39/92 (42%) in the STRYDE and PRECICE cohorts, respectively. Temporary range of motion (ROM) limitations under distraction were registered in 17/48 (35%) segments treated with the STRYDE and 35/92 segments (38%) treated with the PRECICE nail. Osteolysis and periosteal reaction, implant breakage, and pain during lengthening and consolidation is more likely in patients treated with the STRYDE nail compared to the PRECICE nail. Temporary ROM limitations during lengthening occurred independent of the applied device. Implant-related osseous alterations seem to remodel after implant removal.Cite this article: Bone Joint J2023;105-B(1):88-96.

Femoral Discrepancy After Childhood Bone Sarcoma Surgery Can Be Treated With Magnetic Intramedullary Nails.

This study aims to determine whether femoral lengthening with a magnetic motorized intramedullary nail (PRECICE; NuVasive) is safe and effective in patients with discrepancy due to limb salvage performed for bone sarcomas before skeletal maturity. Six patients (male, 4; female, 2) with a mean age of 9.3 years (range, 4.8-12.8 years) at the time of index limb salvage surgery were retrospectively analyzed. Four patients had undergone biological reconstruction with liquid-nitrogen recycled frozen autograft shell and inlaid vascular fibula combination and 2 had undergone nonbiological reconstruction with distal femur modular tumor endoprosthesis. The mean age at PRECICE operation was 16.1 years (range, 13.4-20.1 years). The mean prelengthening femoral discrepancy was measured as 60 mm (range, 39-80 mm). Lengthening was achieved in 5 of these 6 patients. Although the PRECICE nail was successfully implanted in the sixth patient, lengthening could never be performed owing to failure to overcome the chronic diaphyseal nonunion first, as intended with compressive use of the nail. For the other 5 patients, in whom lengthening was performed, the mean lengthening was 45 mm (range, 35-52 mm), the mean ratio of achieved to planned lengthening was 93% (range, 74%-100%), and the mean bone-healing index was 41 days per cm (range, 24-69 days per cm). Mean Musculoskeletal Tumor Society score improved from 25.6 to 27.2 after lengthening. No major complications occurred. The outcomes of this study demonstrate that the PRECICE implant can safely and effectively correct femoral length discrepancy caused by limb salvage performed for osteosarcoma before skeletal maturity. [Orthopedics. 2023;46(1):27-34.].

Correction of post-traumatic lower-limb discrepancy with Precice intramedullary lengthening nails: a review of 34 adults with an average follow-up of 2 years.

Background and purposeWe report results and complications of gradual bone lengthening for post-traumatic lower-limb length discrepancy (LLD) with Precice intramedullary lengthening nails in 34 adults.Patients and methodsInclusion criteria were lowerlimb lengthening using the Precice nail, posttraumatic etiology, age older than 18 years, and minimum follow-up of 12 months after implantation. 34 patients met the inclusion criteria. Radiological and clinical outcome data were collected.ResultsPrecice lengthening was performed in the femur in 28 patients (21 antegrade, 7 retrograde) and in the tibia in 6. Mean patient age at time of surgery was 32 years (18–72). Mean preoperative LLD was 31 mm (20–71). Acute correction of axial or rotational malalignment was performed in 11 segments. At final follow-up (mean 2 years [1.1–3.6]), 33 of 34 nails had been removed. All lengthening sites were healed, and all patients mobilized with full weight-bearing. 14 adverse events occurred in 11 patients and were categorized as problems (n = 5), obstacles (n = 3), and complications (n = 6). Unplanned surgery was necessary in 7 patients, 3 of whom did not complete treatment with Precice.InterpretationCorrection of posttraumatic LLD with or without axial malalignment using Precice intramedullary lengthening nails is associated with a low number of complications and good functional outcome. However, one-fifth of patients in this series needed further unplanned surgery for revision of obstacles or complications.

115 Management of Femoral Non-Union with Post-Traumatic Bone Defect Using Second-Generation PRECICE® Nail - a Case Report

Abstract Introduction The management of post-traumatic bone defects with non-union remains a surgical challenge. Common limb length discrepancy (LLD) procedures involve Masquelet technique, vascularised bone grafts, distraction osteogenesis using external fixators, yet they pose a functional and economical challenge for patients, given high complication rates and need for revision surgery. Magnetically driven PRECICE nails are self-lengthening internal devices activated via an external controller. We present one patient with post-traumatic femoral non-union with concomitant bone defect, using second-generation PRECICE nail. Case Study One 57-year-old gentlemen suffered open femoral fracture after a motorcycle accident. Having previously undergone open reduction internal fixation, he presented to us with atrophic non-union and bone defect, which were simultaneously treated with a second-generation PRECICE nail. Our treatment protocol was based on the strain theory and involved initial distraction by ∼5mm at non-union site, at a rate of 1mm per day, to decrease strain on bone graft cells and promote callus formation. One week later, the non-union site was compressed to close the gap completely. After another four weeks, distraction using the PRECICE nail started, in increments of 0.25mm, four times a day, until the desired length was achieved. The patient achieved union and the initially planned limb lengthening regime was achieved with minimal complications. Conclusions By initially distracting the bone defect by ∼5mm, then compressing the gap, before distraction started, strain on bone graft cells was minimised, allowing robust callus and regenerate growth. Self-lengthening, magnetically driven PRECICE nails can successfully restore union and manage limb length discrepancies with reasonable patient satisfaction and minimal complications.

EP-490 Management of femoral non-union with post-traumatic bone defect using second-generation PRECICE® nail - A Case Report

Abstract Introduction The management of post-traumatic bone defects with non-union remains a surgical challenge. Common limb length discrepancy (LLD) procedures involve Masquelet technique, vascularised bone grafts, distraction osteogenesis using external fixators, yet they pose a functional and economical challenge for patients, given high complication rates and need for revision surgery. Magnetically-driven PRECICE nails are self-lengthening internal devices activated via an external controller. We present one patient with post-traumatic femoral non-union with concomitant bone defect, using second-generation PRECICE nail. Case One 57 year-old gentlemen suffered open femoral fracture after a motorcycle accident. Having previously undergone open reduction internal fixation, he presented to us with atrophic non-union and bone defect, which were simultaneously treated with a second-generation PRECICE nail. Our treatment protocol was based on the strain theory, and involved initial distraction by ∼5mm at non-union site, at a rate of 1mm per day, to decrease strain on bone graft cells and promote callus formation. One week later, the non-union site was compressed to close the gap completely. After another four weeks, distraction using the PRECICE nail started, in increments of 0.25mm, four times a day, until the desired length was achieved. The patient achieved union and the initially planned limb lengthening regime was achieved with minimal complications. Conclusions By initially distracting the bone defect by ∼5mm, then compressing the gap, before distraction started, strain on bone graft cells was minimised, allowing robust callus and regenerate growth. Self-lengthening, magnetically-driven PRECICE nails can successfully restore union and manage limb length discrepancies with reasonable patient satisfaction and minimal complications.

Use of the PRECICE nail for distraction osteogenesis after tumor resection

ABSTRACT Introduction Reconstructing long bone defects following intercalary tumor resection presents an exciting challenge with a greater range of surgical solutions than more typical situations requiring arthroplasty. Segmental bone transport (distraction osteogenesis) is the least utilized option for intercalary reconstruction; however, it arguably provides patients with the most desirable result. Distraction osteogenesis can be used in the management of multiple skeletal conditions including deformity (congenital or acquired), or in the presence of bone defects (by trauma or planned surgical excision). Lack of broader adoption of transport is likely due to the highly technical demands and common complications of utilizing fine-wire fixators via the Ilizarov method. More recently, internal lengthening nails such as the PRECICE nail have been employed to facilitate distraction osteogenesis without the added complexity of external fixation. Areas covered This review will examine the literature on the indications, design, and safety of the PRECICE nail (NuVasive) for intercalary reconstruction after tumor resection. Expert opinion Bone transport using the PRECICE nail represents a viable alternative to Ilizarov distraction and has the benefit of avoiding the complications of an external fixator. For large defects, the PRECICE nail can be supplemented with a locking plate for additional stability and maintenance of limb length.

Use of the Pixel Value Ratio Following Intramedullary Limb Lengthening: Uncomplicated Full Weight-bearing at Lower Threshold Values.

AimsThe pixel value ratio (PVR) can be used to assess regenerate consolidation after lengthening and guide advice for full weight-bearing (FWB). This study aimed to analyse the PVR in adults having femoral lengthening, the time to FWB and compare findings with the reported values in the literature.Materials and methodsA retrospective database review identified 100 eligible patients who underwent lengthening using the PRECICE nail (68 antegrade and 32 retrograde). The PVR was calculated in each cortex on plain radiographs at every visit. The ratio between the regenerate and an average from the adjacent normal bone was calculated and plotted against the clinical decision to allow FWB.ResultsEighty-seven patients (58 men and 29 women) were assessed; eleven had bilateral lengthening and two patients underwent lengthening twice. The median age was 30.5 years. The underlying cause of shortening was post-traumatic in 46%, with the remaining due to a wide variety of causes, including congenital 16%, syndromic 12% and other causes. The median lengthening achieved was 45 mm, at a median of 57.5 days. The PVR increased with each visit (p <0.0001). FWB was allowed at a median of 42 days after the last day of lengthening, with PVR values of 0.83, 0.84, 0.93 and 0.84 for the anterior, posterior, medial and lateral cortex noted, respectively (average 0.85). There were no implant failures, shortening or regenerate fractures. No differences were detected between antegrade and retrograde nails or with lengthening greater or less than 45 mm. One surgeon allowed earlier FWB at median 31 days with no nail failures.ConclusionPVR is a valuable tool that quantifies regenerate maturity and provides objectivity in deciding when to allow FWB after intramedullary lengthening with the PRECICE nail. FWB was permitted at an earlier time point, corresponding with lower PVR values than have been reported in the literature and with no mechanical failure or regenerate deformation.How to cite this articleElsheikh AA, Wright J, Stoddart MT, et al. Use of the Pixel Value Ratio Following Intramedullary Limb Lengthening: Uncomplicated Full Weight-bearing at Lower Threshold Values. Strategies Trauma Limb Reconstr 2022;17(1):14–18.

Technical considerations for the management of segmental osseous defects with an internal bone transport nail

ABSTRACT Introduction Traditionally, distraction osteogenesis has been accomplished with an external fixator. All internal transport utilizing magnetic intramedullary nails is a newer technique for bone reconstruction. The Precice Bone Transport Nail is a new implant that allows for noninvasive transport via a magnetically driven motor. Areas covered This report describes the function of the Bone Transport Nail along with the technical considerations on how to successfully manage bone defects with this new technology. Appropriate use of the nail, preoperative planning, intraoperative considerations, and postoperative management are discussed in detail. Expert opinion The Precice Bone Transport Nail utilizes the technology of the original Precice nail to provide an all-internal option for reconstruction of intercalary defects. This obviates the need for an additional plate with a standard Precice nail when performing bone transport and allows for a less invasive option that decreases operating room time. It provides a more cosmetic result than external fixation and avoids the risks of pin tract infection. Preoperative planning is essential to appropriate execution of the operative procedure and to perform a successful transport. A thorough understanding of the nail design and limitations are a prerequisite as this implant is significantly different from a standard intramedullary nail.

Limb Lengthening With Precice Intramedullary Lengthening Nails in Children and Adolescents.

The Precice intramedullary bone lengthening nail has been used in our department since 2013. We sought to determine the efficacy and safety of intramedullary limb lengthening with Precice nails in children and adolescents. We retrospectively investigated patients 18 years and younger who underwent lower-limb lengthening using the Precice nail. Radiologic and clinical outcome data were obtained from a prospective database. The minimum postimplantation follow-up was 12 months. Between March 2013 and March 2020, 161 patients underwent limb lengthening with a Precice nail; 76 patients met the inclusion criteria. We used 84 nails in 76 patients (68 femurs and 16 tibias). Femoral nails were inserted using an antegrade approach in 57 patients and a retrograde approach in 11. The mean age at surgery was 16 years (range, 9 to 18 y). The mean lengthening was 33 mm (range, 14 to 80 mm) with additional acute axial or rotational malalignment correction in 16 segments. At the last follow-up (mean=2.1, years; range, 1 to 5 y), all regenerates had healed and all patients were mobile with full weight-bearing. Complications that necessitated surgical revision occurred in 6 patients (8%), and the desired lengthening was not achieved in 2 patients. Postlengthening malalignment occurred in 4 patients (5 tibial nails). The weight-bearing index, defined as days from surgery to full weight-bearing/cm of lengthening, was a mean of 45 days (range, 7 to 127 d/cm). The Precice nail facilitated reliable and safe bone lengthening and was associated with a low complication rate. Correction of additional malalignment was possible by applying intraoperative acute correction or guided growth. Level IV-therapeutic study investigating the results of treatment.

Complications in Elective Removal of 271 Bone Lengthening Nails (FITBONE, PRECICE and STRYDE).

BackgroundIntramedullary lengthening nails have shown excellent short-term results. The FITBONE and the PRECICE nail are the two most commonly used intramedullary lengthening nails. The manufacturer of each nail recommends the removal of the implant after the completion of the treatment. Despite the need for removal of each nail, the authors are not aware of any prior publications documenting the results of standard intramedullary lengthening nail removal. Therefore, the aim of this study was to examine the intraoperative and postoperative complications of elective intramedullary lengthening nail removals.Materials and methodsWe performed a retrospective chart review of patients operated with intramedullary lengthening nails at two limb reconstruction centres (one in the United States, and the second in Denmark). Data retrieved from the patient charts included patient demographics, nail information and any complications occurring at or after nail removal. Only lower limb lengthening with FITBONE and PRECICE or STRYDE nails that had an elective nail removal was included.ResultA total of 271 elective nail removals were included in the study. Complications occurred during 3% of the nail removals and in 13% after nail removal. There were 18 reported cases with postoperative knee pain. All these patients had nail removal through the knee joint, representing 8% of the retrograde femur nail removals and 7% of the tibia nail removals. Four postoperative fractures occurred, of which two needed surgery. Eleven percent of femur removals and 26% of tibial removals sustained a complication.Conclusion and clinical significanceThis study emphasises the importance of adequate follow-up of the bone lengthening patient even after the nail has been removed. It also shows that the recommended removal of the intramedullary nail (IMN) lengthening nails must be included in studies reporting on the overall risks of complications using bone lengthening nails.How to cite this articleFrost MW, Kold S, Rahbek O, et al. Complications in Elective Removal of 271 Bone Lengthening Nails (FITBONE, PRECICE and STRYDE). Strategies Trauma Limb Reconstr 2021;16(2):110–115.

Comparison of forces generated using compression plating versus a magnetic lengthening nail in a sawbones femur model

BackgroundThe purpose of this study is to compare compression generated by a Precice magnetic lengthening intramedullary nail and a 5.0 mm limited contact dynamic compression plate. MethodsTransverse osteotomy sites were created in the femoral shaft of ten Sawbones fourth generation composite femurs. Antegrade 10-degree trochanteric Precice nails and 8-hole, 5.0 mm plates were used for fixation. The plates were compressed by placing a neutral screw and three eccentrically drilled compression screws on alternating sides of the osteotomy. Average compression and distribution of compression were compared, and P-values <0.05 were considered statistically significant. FindingsThe Precice nail generated an average of 2.38 megapascal across the osteotomy sites. The plate generated an average of 0.70 megapascal (P < 0.001) with the initial compression screw, 0.93 megapascal (P < 0.001) after the second screw, and 1.04 megapascal (p < 0.001) after the final screw. The distribution of compression was assessed utilizing a polar transformation to compare pressure values. We found that the distribution of compression was more circumferentially uniform in the Precice nail group (P = 0.046). InterpretationThis study demonstrates that an electromagnetic intramedullary device is capable of generating significantly higher compression, in a more uniform distribution, than a 5.0 mm limited contact dynamic compression plate in a Sawbones model. The results indicate that electromagnetic intramedullary nail systems may be an ideal alternative to compression plating for treatment of at-risk fractures, nonunions, delayed unions, and intercalary allograft reconstruction.

The PRECICE nail system: The initial Kuwaiti experience

Objectives: The PRECICE system is an implantable limb lengthening intramedullary nail with remotely magnetically controlled distractors indicated for limb length discrepancy (LLD) and short stature treatment. This study reports the initial experience of the Kuwaiti deformity correction unit in utilizing the PRECICE system. Methods: Ten patients (four females and six males) were included in this study. All cases were operated using the PRECICE nail system (five antegrade femoral nails, three retrograde femoral nails, and two tibial nails). All surgeries were performed during January 2019 to February 2020. Results: The mean age of participants was 20 years (12–33 years), with a 21.6 kg/m2 mean body mass index (17–28). LLD etiologies (mean LLD = 39 mm) were congenital (n = 2), developmental (n = 2), post-traumatic non-union (n = 1), post-traumatic malunion (n = 1), post-traumatic physeal arrest (n = 1), and post-deformity correction and lengthening of the contralateral side with circular frame (n = 3). The mean distraction rate was 0.97 mm/day (range: 0.75–1.2 mm/day). Mean lengthening was 39 mm (range: 20–60 mm). Healing was confirmed at 76 days on average (range: 50–120 days). All patients reached full consolidation to regenerate bone, normal alignment, and normal joint orientation. Antegrade femur lengthening was done in five patients. One patient with a previous knee fixed flexion deformity of 25° improved to a 5° lag of extension. No complications were observed during the lengthening procedures. All the patients were followed up for a minimum of 12 months. Conclusion: The PRECICE nail system was successful in lengthening cases with different etiologies, achieving target lengths without complications. All the patients had reported excellent functional outcomes.

Limb lengthening with PRECICE magnetic nail in pediatric patients: A systematic review

BACKGROUNDLimb lengthening techniques play an increasingly important role in the pediatric orthopedic field. The principles of the osteogenesis distraction bonded traditionally with external fixators; however, the recent deployment of fully implantable systems has been able to overcome severities related to external fixators. The PRECICE® is an implantable limb lengthening intramedullary nail system that is remotely controlled and magnetically driven.AIMTo review the current literature available on this matter in order to assess the PRECICE clinical and radiological outcomes and its possible complications in a population of pediatric patients undergoing limb lengthening.METHODSOnly five studies met the inclusion criteria and were consequently included in the review for a total of 131 patients and 135 femurs. The clinical and radiological outcomes of interest were: the main lengthening obtained, the distraction rate, the period of time to full weight bearing, the consolidation index, and the Association for the Study and Application of Methods of Ilizarov score.RESULTSIn conclusion, data collected from the articles under investigation were comparable with the exception of the consolidation index. Unfortunately, the study population was too small and the patients’ follow-up was too short to make definitive conclusions. CONCLUSIONThis review shows that the PRECICE Nail System is still a therapeutic challenge in limb lengthening for pediatric orthopedic surgeons; however, careful pre-operative planning and an accurate surgical technique could allow the correction of more complex deformities with a low rate of complications.

Efficacy of PRECICE Nail in Treatment of Adult Patients With Posttraumatic Femoral Leg Length Discrepancy

Posttraumatic, limb length discrepancy in adults is a challenge to treat, and multiple treatment protocols over the years have shown varying levels of success and complications. Before the introduction of the PRECICE nail in 2011, our preferred method of limb lengthening used an Ilizarov or Taylor Spatial frame. To assess the PRECICE nail, we evaluated the accuracy and complications during treatment in a series of skeletally mature patients with posttraumatic femoral limb length discrepancy. The surgical technique along with a case series of 8 patients are described in detail. On average, the target lengthening for the PRECICE nail was 44 mm, and all patients achieved lengthening within 2 mm and complete bony consolidation. The only observed complication in our series was a broken screw 1 year after the patient started weight-bearing. The PRECICE nail demonstrated promising results and was useful for bone regeneration and consolidation without the need for additional procedures. The rate of complications was low compared with previous methods, making this device an excellent treatment option.

Retrograde Extramedullary Lengthening of the Femur Using the PRECICE Nail: Technique and Results.

Lengthening of long bones by distraction osteogenesis is now possible using intramedullary lengthening nails. Constraints of bone size, medullary canal obstruction, and the presence of an open physis are contraindications in skeletally immature patients. We present a technique describing the "off-label" use of a magnetic lengthening nail placed extramedullary and in retrograde manner, for lengthening of the femur in skeletally immature patients. A retrospective review of 5 skeletally immature patients with significant length discrepancy of the femur are presented along with a description of the surgical technique. Data collected included age, sex, date of surgery, diagnosis, presence of associated deformities, the magnitude of length discrepancy, the amount of length gained, the amount of time to achieve full weight-bearing, the time to hardware removal, and any complications. There were 5 patients (3 females). The mean age was 7.2±2.7 years (4 to 10 y). The mean limb length discrepancy was 6.5±3.7 cm (3.5 to 11 cm). A mean length of 3.46±0.4 cm (3.1 to 4 cm) was achieved which represents 12.9±1.8% (10.32 to 13.47%) of the bone length. The time taken to achieve full weight-bearing ambulation was 89.2±19.3 days (60 to 109 d) or 12.7 weeks. All hardware was removed 247.6±215.6 days (99 to 628 d) after surgery. Patients were followed up for a mean duration of 19.2 months (11 to 30 mo). No supplemental fixation was required and no complications were noted. Acute deformity correction was also performed at the time of surgery in 2 patients who had distal femur valgus deformity. Retrograde extramedullary lengthening of the femur is an option that should be considered for limb length equalization in skeletally immature patients. It avoids the inconvenience of external fixation and can be used to simultaneously correct deformities of the distal femur. Although the total amount of length gained is modest, we believe it is a promising limb lengthening technique that merits further investigation. Level III.