Femoral lengthening with lengthening over a nail has fewer complications than intramedullary skeletal kinetic distraction

A Novel Electromechanical Intramedullary Nail System for Limb Lengthening

Background/Purpose of the Study

Many methods have been developed to treat leg length discrepancies. Extensible intramedullary nails are the most commonly used systems. However, complications such as excessive distraction, blockage of the nail, aditional surgery, uncontrolled lengthening and much pain occur during the use of these systems, and the desired success rate cannot be achieved. This study aims to develop a new extensible intramedullary system with two mechanisms (electronical and mechanical) for femur and tibia that treats leg length inequalities in a way that allows lengthening without complications as much as possible and does not require a second surgical intervention. It was planned to perform basic mechanical and cadaver functional tests of the new system, which will be designed and developed for this purpose.

Methods

The 3D design of the system has been completed with 3D computer software. A compact system has been developed that is mechanically activated by sudden axial loading and electronically activated by a controllable electric motor. Basic mechanical and functional tests of the new system have been performed within a cadaver.

Results

The rapid prototype of the system with electronical and mechanical units has been produced. As a result of the mechanical tests (axial loading), the nail was found to be resistant to compression forces. Its application to the cadaver and function tests was successfully performed.

Conclusions

We believe that the system we have developed will have advantages, such as working principle, ease of application, controlled lengthening, patient mobility compared to existing leg lengthening methods. The success of the system in practice will be evaluated by in-vivo animal experiments after more detailed mechanical experiments on cadavers. According to the results, it will be ready for human use by performing necessary restorations.

The Management of Tibial Bone Defects: A Multicenter Experience of Hexapod and Ilizarov Frames

INTRODUCTION

Bone defects may be managed with bone transport or acute shortening and lengthening using circular external fixation devices. We performed a multicenter retrospective cohort study to compare the outcomes between the Ilizarov frames and hexapod frames for the management of bone defects.

METHODS

Patients treated for bone defects using either Ilizarov or hexapod frames were included for analysis in two specialist institutions. Primary outcomes were time to consolidation, bone healing index (BHI), and external fixator index (EFI). Radiographic parameters included the medial proximal tibial angle, lateral distal tibial angle, posterior proximal tibial angle, and anterior distal tibial angle.

RESULTS

There were 137 hexapods and 90 Ilizarov frames in total. The mean time to follow-up was 3.7 years in the hexapod group and 4.0 years in the Ilizarov group. Hexapods had a significantly lower time to consolidation (253 days versus 449 days) (P < 0.0001) and BHI (59.1 days/cm versus 87.5 days/cm) (P < 0.0001). Hexapods had a significantly better EFI (72.3 days/cm versus 96.1 days/cm) (P = 0.0009).

CONCLUSION

Hexapods may confer a significant advantage over Ilizarov frames in the management of bone defects. Time to consolidation, radiographic parameters, BHI, and EFI are all superior in hexapods.

Femoral Magnetic Lengthening After Distal Femur Endoprosthetic Reconstruction in a Pediatric Patient: A Case Report

CASE

A 10-year-old boy with osteosarcoma of the left distal femur underwent resection with compressive osseointegration endoprosthetic reconstruction, gradually resulting in a 4.5-cm leg-length difference with significant predicted progression. Two years after resection, he underwent right distal femur and proximal tibia epiphysiodesis and placement of a left femoral magnetic lengthening nail. At 2 years after lengthening and skeletal maturity, the patient has symmetric limb lengths, no pain, and returned to sports.

CONCLUSION

A magnetic lengthening nail with contralateral epiphysiodesis is a viable option for correcting limb-length discrepancy after distal femur endoprosthetic reconstruction in a pediatric patient.

Treatment of Angular Deformity and Limb Length Discrepancy With a Retrograde Femur Magnetic Intramedullary Nail: A Fixator-assisted, Blocking Screw Technique

BACKGROUND

Fixator-assisted nailing techniques that incorporate magnetic internal lengthening nails (MILNs) permit acute deformity correction and then gradual limb lengthening without needing postoperative external fixators.

PURPOSES

We sought to investigate the safety and accuracy of a fixator-assisted, blocking screw technique using retrograde MILNs for the correction of LLD and limb malalignment.

METHODS

Forty-one patients (13 patients with genu varum and 28 patients with genu valgum) with LLD treated with fixator-assisted, blocking screw retrograde MILN reconstruction were included. Preoperative LLD, mechanical axis deviation, and joint orientation angles were compared with values at the end of treatment, and bone healing indices were calculated. Perioperative complications were tracked.

RESULTS

Preoperatively, the mean mechanical lateral distal femoral angle of the varus cohort was 98 ± 12°, whereas the mean lateral distal femoral angle of the valgus cohort was 82±4°. Both cohorts had an average 3-cm LLD. 99% of the planned limb lengthening was achieved. Final LDFAs were 91 ± 6° and 89 ± 4° in the varus and valgus cohorts, respectively, and the limb mechanical axis angles were normalized. 10 patients underwent a total of 21 returns to the operating room. Most commonly, this involved percutaneous injection of bone marrow aspirate concentrate to bone regenerate exhibiting delayed union (6 patients).

CONCLUSIONS

The use of a retrograde MILN with a fixator-assisted, blocking screw technique is an effective means of acute deformity correction and gradual limb lengthening through minimal incisions. The accuracy of deformity correction relies on intraoperative execution of the appropriate nail start site, osteotomy location, and placement of blocking screws.

What Factors Correlate With Length of Stay and Readmission After Limb Lengthening Procedures? A Large-database Study

BACKGROUND

Indications and techniques for limb lengthening procedures have evolved over the past two decades. Although there are several case series reporting on the complications and efficacy of these techniques, limited data are available on length of stay and hospital readmission rates after these procedures.

QUESTIONS/PURPOSES

(1) What is the median length of stay after lower limb lengthening procedures, and is variability in patient demographics, preoperative diagnosis, and surgical technique associated with length of stay? (2) What is the 1-year readmission rate after lower limb lengthening procedures? (3) Is variability in patient demographics, preoperative diagnosis, and surgical technique associated with varying rates of hospital readmission?

METHODS

Patients who underwent femoral or tibial lengthening from 2005 to 2015 in seven states were identified using the Healthcare Cost and Utilization Project (HCUP) State Inpatient Databases. These databases include a large, diverse group of patients across a wide range of hospitals and socioeconomic backgrounds with inclusion of patients regardless of payer. Between 2005 and 2015, there were 3979 inpatient admissions that were identified as involving femoral and/or tibial lengthening procedures based on ICD-9 procedure codes; of those, 2% (97 of 3979) of the inpatient admissions were excluded from analysis because they had ICD-9 procedure codes for primary or revision hip or knee arthroplasty, and 10% (394 of 3979) of the inpatient admissions were excluded because they involved repeated admissions of patients with previous hospitalization data within the database. This yielded 3488 patients for analysis. The median (interquartile range) age of patients was 18 years (12 to 41), and 42% (1481 of 3488) of patients were women. A total of 49% (1705 of 3469) of patients were children (younger than 18 years), 19% (675 of 3469) were young adults (18 to 34 years), 24% (817 of 3469) were adults (35 to 59 years), and 8% (272 of 3469) were seniors (60 years and older). Length of stay and rates of readmission at 1 year after the lengthening procedure were calculated. Univariate analysis was performed to examine associations between age, race, payment method, underlying diagnosis, bone lengthened, and lengthening technique with length of stay and readmission rate. Factors found to be significantly associated with the outcome variables (p < 0.05) were further examined with a multivariate analyses.

RESULTS

Included patients had a median (IQR) length of hospital stay of 3 days (2 to 4). Given the poor explanatory power of the multivariate model for length of stay (R 2 = 0.03), no meaningful correlations could be drawn between age, race, underlying diagnosis, lengthening technique, and length of stay. The overall 1-year readmission rate was 35% (1237 of 3488). There were higher readmission rates among adult patients compared with pediatric patients (odds ratio 1.78 [95% confidence interval 1.46 to 2.18]; p < 0.001), patients with government insurance compared with commercial insurance (OR 1.28 [95% CI 1.05 to 1.54]; p = 0.01), and patients undergoing lengthening via external fixation (OR 1.61 [95% CI 1.29 to 2.02]; p < 0.001) or hybrid fixation (OR 1.81 [95% CI 1.38 to 2.37]; p < 0.001) compared with lengthening with internal fixation only.

CONCLUSION

When counseling patients who may be candidates for limb lengthening, providers should inform individual patients and their caretakers on the anticipated length of hospital stay and likelihood of hospital readmission based on our findings. Adult patients, those with government insurance, and patients undergoing hybrid or external fixator limb lengthening procedures should be advised that they are at greater risk for hospital readmission. The relationship of specific patient-related factors (such as severity of deformity or associated comorbidities) and treatment-related variables (such as amount of lengthening, compliance with physical therapy, or surgeon's experience) with clinical outcomes after lower limb lengthening and the burden of care associated with hospital readmission needs further study.

LEVEL OF EVIDENCE

Level III, therapeutic study.

All-Internal Limb Lengthening with Simultaneous Corrective Osteotomy After Internal Hemipelvectomy: A Case Report

CASE

A 27-year-old woman with a Grade II chondrosarcoma in the right acetabulum underwent a Type II internal hemipelvectomy with an ischiofemoral fusion. She developed a 7.0-cm functional limb-length discrepancy with adduction of the hip at rest. Four years after surgery, she underwent a corrective osteotomy and limb lengthening with a magnetic lengthening nail. Eleven years after tumor resection and a successful pregnancy, she had symmetric leg lengths and ambulated without an assistive device.

CONCLUSIONS

A magnetic lengthening nail is a viable option for correcting limb-length discrepancies after hemipelvectomy. If necessary, a simultaneous corrective proximal femoral osteotomy can be performed.

Are internal lengthening devices effective and associated with less complications compared to other lengthening devices? A systematic review and meta-analysis

Internal lengthening devices became more popular than external fixators. This was attributed to their effectiveness and lower complication rates. However, this is an assumption that is not on the basis of solid scientific evidence. Therefore, this study systematically reviewed the quality and strength of evidence supporting femoral internal lengthening devices' effectiveness and their associated complications. Six electronic databases (PubMed, Cochrane, Sage, Embase, Web of Science and Scopus) were searched from inception until 20 June 2020. Further, all included articles' bibliographies were searched manually. After screening of retrieved articles, five studies were eligible for qualitative and quantitative synthesis. Studies were assessed by two independent assessors using a modified 'assessment of the methodological quality both of randomized and nonrandomized studies of health care interventions'. Further, meta-analysis was conducted to compare the procedure's effectiveness, in terms of healing index and major complications incidence. Our findings showed internal validity as the major source of bias whereas external validity was the least. For healing index, there is limited evidence that internal lengthening devices lower healing index by 0.45 months/cm (95% CI, -0.62 to -0.28; P < 0.01) compared to LON/external fixators. The incidence of major complications, that were directly related to the procedures, did not differ between internal lengthening devices and other fixators (risk ratio=0.97; 95% CI, 0.39-2.44; P < 0.95). This review provides evidence that supports lower healing index and similar complications associated with internal lengthening devices compared to other procedures of femoral lengthening. However, the evidence is very limited to draw a solid conclusion.

Limb Lengthening With Precice Intramedullary Lengthening Nails in Children and Adolescents

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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 OF EVIDENCE

Level IV-therapeutic study investigating the results of treatment.

[Progress of remote-control intramedullary lengthening nail and its clinical treatment concept]

Ilizarov's technology is an internationally recognized clinical treatment method for limb orthopedics, but there are many complications related to external fixation. With the development and progress of the times, the remote-control intramedullary lengthening nails had risen to prominence on the international stage as the second generation of orthomelic technology based on Ilizarov's technology. Since the first remote-control intramedullary lengthening nail appeared in the 1980s, after more than 40 years of development, there are currently more than 3 types of extension mechanisms in remote-control intramedullary lengthening nails and a mature and stable clinical treatment model has been formed during the past long-term clinical treatment and experiments, such as the End-Point-First (EPF) program proposed by Professor Peter H. Thaller in Germany. Compared with Ilizarov's technology, the remote-control intramedullary lengthening nail has obvious advantages in convenience, comfort, risk of infection, soft tissue injury, postoperative pain, and controllability of limb lengthening. This article mainly introduces the development and clinical treatment concept of remote-control intramedullary lengthening nail and the latest clinical treatment status of limb lengthening therapy abroad, hoping to provide new cognition and ideas for the further development of limb orthopedics in China.

Implant failure after externally magnetic-controlled nail lengthening

The number of intramedullary procedures to treat leg length discrepancy (LLD) has risen in the past decade and this has led to increased complications such as nail breakage. The aim of this study was to reveal our experience with implant failure after externally magnetic-controlled telescopic bone lengthening. We observed nail-breakage in 4 out of 24 patients (16.7%) after 6 to 15 months (median 13.5 months) following lower limb lengthening for LLD due to non-union or insufficient bone healing. Three femora and one tibia were treated in one posttraumatic and three congenital cases. Three out of the four patients had an elevated Charleston Comorbidity Index (CCI). Revision surgery involved removal of the broken nail and implantation of a trauma nail. At final follow-up all patients showed subjective satisfaction, achievement of desired lengthening with complete bone healing. Based on our results no unequivocal risk factor including number of previous surgeries, comorbidities and age was identified. In cases of delayed bone formation, early revision surgery with an exchange to a trauma nail has to be considered to prevent breakage of the intramedullary telescopic device.

Management of post-traumatic femoral defects with a monorail external fixator over an intramedullary nail

PURPOSE

The management of limb-length discrepancy secondary to traumatic femoral bone loss poses a unique challenge for surgeons. The Ilizarov technique is popular, but is associated with long external fixator time and many complications. This retrospective study assessed outcomes of post-traumatic femoral defects managed by monorail external fixation over an intramedullary nail.

METHODS

Eight patients were included from October 2015 to May 2019 with post-traumatic femoral defects that underwent treatment with monorail fixator-assisted intramedullary nailing. Primary outcome was time to bone union and bone results according to ASAMI classification. Secondary outcomes were lengthening index, consolidation time and index, external fixator index (EFI), time to partial weight bearing(PWB) and full weight bearing (FWB), and complications. Patient reported outcome measures including EQ-5D-5L, SF-36, Oxford knee scores (OKS), and Oxford hip scores (OHS) were recorded after recovery.

RESULTS

Mean follow-up time was 227 weeks. Average bone defect size was 9.69 cm. Average consolidation time and index were 11.35 months and 1.24 months/cm, respectively. Mean lengthening and external fixator index were 20.2 days/cm and 23.88 days/cm, respectively. On average, patients achieved FWB and bone union 56.25 weeks and 68.83 weeks after bone transport initiation, respectively. Two patients had docking site non-union, five patients had pin site infections, and two patients had osteomyelitis. EQ-5D-5L and EQ-VAS scores were compared to UK population norms (p = 0.104, p = 0.238, respectively). Average OKS was 32.17 and OHS was 34.00.

CONCLUSION

Monorail external fixation over an intramedullary nail is an effective option for post-traumatic femoral defects, reducing external fixator time and returning patients' quality of life to a level comparable with the normal population.

Knee Joint Bone Defects: Reconstruction With Bone Transport and Arthrodesis

BACKGROUND

The increasing in primary total knee arthroplasty has led to an increase in infectious complications, revision surgery, and bone loss. Knee joint bone defects (KJBD) may be managed using bone transport and arthrodesis with Ilizarov or bone transport over nail (BTON) techniques. The aim of this study is to compare both techniques in the reconstruction of KJBDs.

METHODS

This was a retrospective cohort study of 29 patients with extensive KJBD. All patients underwent reconstruction of the KJBD using bone transport (either Ilizarov or BTON techniques). The primary outcome variables for comparison between the two groups included time in frame (days), external fixation index (EFI, days/cm), residual limb length discrepancy (cm), and complications (Caton classification).

RESULTS

Gender and age profiles were comparable. Mean time spent in frame for bone transport was 566 days (σ = 236, 95% CI 429-702) for the Ilizarov cohort and 191 days (σ = 162, 95% CI 101-280) for BTON (P < .0001). EFI for the period of bone transport was 75.1 d/cm (σ = 41.5, 95% CI 51.1- 99.1) for the Ilizarov cohort and 24.7 d/cm (σ = 24.0, 95% CI 11.4-38) for BTON (P = .0004). Union, limb length discrepancy and complication rates were comparable between both groups.

CONCLUSION

For the management of KJBD after failed total knee arthroplasty, BTON is preferred due to significantly less time spent in frame, lower EFI, and higher rates of normal mechanical alignment. The Ilizarov method may be useful when there is a contraindication to BTON.

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.

Focal osteolysis and corrosion at the junction of Precice Stryde intramedullary lengthening device : preliminary clinical, radiological, and metallurgic analysis of 57 lengthened segments

Aims

This study aims to enhance understanding of clinical and radiological consequences and involved mechanisms that led to corrosion of the Precice Stryde (Stryde) intramedullary lengthening nail in the post market surveillance era of the device. Between 2018 and 2021 more than 2,000 Stryde nails have been implanted worldwide. However, the outcome of treatment with the Stryde system is insufficiently reported.

Methods

This is a retrospective single-centre study analyzing outcome of 57 consecutive lengthening procedures performed with the Stryde nail at the authors’ institution from February 2019 until November 2020. Macro- and microscopic metallographic analysis of four retrieved nails was conducted. To investigate observed corrosion at telescoping junction, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDX) were performed.

Results

Adjacent to the nail’s telescoping junction, osteolytic changes were observed in bi-planar radiographs of 20/57 segments (35%) after a mean of 9.5 months (95% confidence interval 7.2 to 11.9) after surgery. A total of 8/20 patients with osseous alterations (40%) reported rest and ambulation pain of the lengthened segment during consolidation.

So far, 24 Stryde nails were retrieved and in 20 (83%) macroscopic corrosion was observed at the nail’s telescoping junction. Before implant removal 11/20 radiographs (55%) of lengthened segments with these 20 nails revealed osteolysis. Implant retrieval analysis by means of SEM showed pitting and crevice corrosion. EDX detected chromium as the main metallic element of corrosion.

Conclusion

Patients are exposed to the risk of implant-related osteolysis of unclear short- and long-term clinical consequences. The authors advocate in favour of an early implant removal after osseous consolidation.

Cite this article: Bone Joint Res 2021;10(7):425–436.

Cost Comparison of Tibial Distraction Osteogenesis Using External Lengthening and Then Nailing vs Internal Magnetic Lengthening Nails

Aim and objective

Tibial lengthening can be performed by distraction osteogenesis via lengthening and then nailing (LATN) or by using a magnetic lengthening nail (MLN). MLN avoids the complications of external fixation while providing accurate and easily controlled lengthening. Concerns exist still regarding the high upfront cost of the magnetic nail, which serves to limit its use in resource-poor areas and decrease adoption among cost-conscious surgeons. The purpose of this study was to compare the hospital, surgeon, and total cost between LATN and MLN when used for tibial lengthening.

Materials and methods

A retrospective review was performed comparing consecutive tibial lengthening using either LATN (n = 17) or MLN (n = 15). The number of surgical procedures and time to union were compared. Surgeon and hospital payments were used to perform cost analysis after adjusting for inflation using the consumer price index (CPI).

Results

Patients treated with MLN underwent fewer surgeries (3.6 vs 2.8; p < 0.001) but had a longer time to union as compared with patients treated with LATN (19.79 vs 27.84 weeks; p = 0.006). Total costs were similar ($50,345 vs $46,162; p = 0.249) although surgeon fees were lower for MLN as compared with LATN ($6,426 vs $4,428; p < 0.001).

Conclusion

LATN and MLN had similar overall costs in patients undergoing tibial lengthening. MLN was associated with fewer procedures but a longer time to union as compared with LATN.

Clinical significance

Despite an increased upfront cost in MLN, there was no difference in total cost between LATN and MLN when used for tibial lengthening. Thus, in cases where either method is feasible, cost may not be a deciding factor when selecting the appropriate treatment.

How to cite this article

Dvorzhinskiy A, Zhang DT, Fragomen AT, et al. Cost Comparison of Tibial Distraction Osteogenesis Using External Lengthening and Then Nailing vs Internal Magnetic Lengthening Nails. Strategies Trauma Limb Reconstr 2021;16(1):14-19.

Lengthening Nails for Distraction Osteogenesis: A Review of Current Practice and Presentation of Extended Indications

Purpose

Circular frames have been the gold standard of treatment for complex deformity corrections and bone loss. However, despite the success of frames, patient satisfaction has been low, and complications are frequent. Most recently, lengthening nails have been used to correct leg length discrepancies. In this article, we review the current trends in deformity correction with emphasis on bone lengthening and present our case examples on the use of lengthening nails for management of complex malunions, non-unions, and a novel use in bone transport.

Materials and methods

A nonsystematic literature review on the topic was performed. Four case examples from our institute, Brighton and Sussex University Hospitals, East Sussex, England, UK, were included.

Results

New techniques based on intramedullary bone lengthening and deformity correction are replacing the conventional external frames. Introduction of lengthening and then nailing and lengthening over a nail techniques paved the way for popularization of the more recent lengthening nails. Lengthening nails have gone through evolution from the first mechanical nails to motorized nails and more recently the magnetic lengthening nails. Two case examples demonstrate successful use of lengthening nails for management of malunion, and two case examples describe novel use in management of non-unions, including the first report in the literature of plate-assisted bone segment transport for the longest defect successfully treated using this novel technique.

Conclusion

With the significant advancement of intramedullary lengthening devices with lower complications rates and higher patient satisfaction, the era of the circular frame may be over.

How to cite this article

Barakat AH, Sayani J, O'Dowd-Booth C, et al. Lengthening Nails for Distraction Osteogenesis: A Review of Current Practice and Presentation of Extended Indications. Strategies Trauma Limb Reconstr 2020;15(1):54–61.

Tibial lengthening using a retrograde magnetically driven intramedullary lengthening device in 10 patients with preexisting ankle and hindfoot fusion

Background and purpose - Motorized intramedullary lengthening nails (ILNs) have been developed as an alternative to external fixators for long bone lengthening. The antegrade approach represents the standard method for tibial ILN insertion. In patients with preexisting ankle and hindfoot fusion a retrograde approach provides an alternative technique that has not been evaluated so far. We report the outcome of this method in 10 patients. Patients and methods - This retrospective study included 10 patients (mean age 18 years [13-25]) with preexisting ankle and hindfoot fusion who underwent tibial lengthening with a retrograde ILN (PRECICE). The mean leg length discrepancy (LLD) was 58 mm (36-80). The underlying conditions were congenital (n = 9) and post tumor resection (n = 1). The main outcome measures were: ILN reliability, distraction achieved, distraction index (DIX), time to bone healing, consolidation index (CIX), complications, and functional results. Results - All patients achieved the goal of lengthening (mean 48 mm [26-80]). Average DIX was 0.6 mm/day (0.5-0.7) and mean CIX was 44 days/cm (26-60). Delayed consolidation occurred in 2 patients and healed after ILN dynamization or nail exchange with grafting. Toe contractures in 2 other patients were resolved with physiotherapy or tenotomy. Until last follow-up (mean 18 months [12-30]) no true complications were encountered, knee motion remained unaffected, and full osseous consolidation occurred in all patients. Interpretation - In patients with LLD and preexisting ankle and hindfoot fusion distal tibial lengthening using a retrograde ILN is a reliable alternative to the standard approach with equivalent bone healing potential and low complication rates leaving the knee unaffected.

How should we lengthen post-traumatic limb defects? a systematic review and comparison of motorized lengthening systems, combined internal and external fixation and external fixation alone

PURPOSE

Various external fixation systems for lower extremity long bone deformities have been used to various degrees of success, while newer mechanical lengthening nail (MLN) systems offer the potential for improved patient outcomes. Proponents of MLNs argue that they reduce the number of operations, infectious complications, and improve quality of life; however, the evidence to support these claims is scant. This systematic review aims to evaluate the optimal lengthening system for treating post-traumatic long bone deformity.

METHODS

The systematic review was conducted in accordance with PRISMA guidelines. PUBMED, EMBASE, CINAHL, and the Cochrane Library were searched for comparative studies of lengthening techniques among adult patients with axial deformities. Studies were screened and data extracted in duplicate. Treatment groups were pooled into external fixation (EF) alone, combined internal and external fixation (CIF), and mechanical lengthening nail (MLN). Outcomes were mean lengthening achieved, lengthening index, and reported complications.

RESULTS

Thirteen studies with 725 patients (mean age: 29.6 years, 74% male) were included. Nearly all of the studies were either prospective or retrospective cohort studies (n = 12), with one randomized controlled trial of moderate study quality. The mean limb lengthening achieved, lengthening index, and rate of reoperation were similar among the MLN, EF, and CIF groups.

CONCLUSION

The purported decreased the duration of lengthening and the risk of reoperation associated with MLNs was not demonstrated in this review. Patients with post-traumatic leg length deformities remain a challenging patient population to treat, with intervention being associated with high rates of infectious complications and need for revision operations.

How should we lengthen post-traumatic limb defects? a systematic review and comparison of motorized lengthening systems, combined internal and external fixation and external fixation alone

PURPOSE

Various external fixation systems for lower extremity long bone deformities have been used to various degrees of success, while newer mechanical lengthening nail (MLN) systems offer the potential for improved patient outcomes. Proponents of MLNs argue that they reduce the number of operations, infectious complications, and improve quality of life; however, the evidence to support these claims is scant. This systematic review aims to evaluate the optimal lengthening system for treating post-traumatic long bone deformity.

METHODS

The systematic review was conducted in accordance with PRISMA guidelines. PUBMED, EMBASE, CINAHL, and the Cochrane Library were searched for comparative studies of lengthening techniques among adult patients with axial deformities. Studies were screened and data extracted in duplicate. Treatment groups were pooled into external fixation (EF) alone, combined internal and external fixation (CIF), and mechanical lengthening nail (MLN). Outcomes were mean lengthening achieved, lengthening index, and reported complications.

RESULTS

Thirteen studies with 725 patients (mean age: 29.6 years, 74% male) were included. Nearly all of the studies were either prospective or retrospective cohort studies (n = 12), with one randomized controlled trial of moderate study quality. The mean limb lengthening achieved, lengthening index, and rate of reoperation were similar among the MLN, EF, and CIF groups.

CONCLUSION

The purported decreased the duration of lengthening and the risk of reoperation associated with MLNs was not demonstrated in this review. Patients with post-traumatic leg length deformities remain a challenging patient population to treat, with intervention being associated with high rates of infectious complications and need for revision operations.

How should we lengthen post-traumatic limb defects? a systematic review and comparison of motorized lengthening systems, combined internal and external fixation and external fixation alone

PURPOSE

Various external fixation systems for lower extremity long bone deformities have been used to various degrees of success, while newer mechanical lengthening nail (MLN) systems offer the potential for improved patient outcomes. Proponents of MLNs argue that they reduce the number of operations, infectious complications, and improve quality of life; however, the evidence to support these claims is scant. This systematic review aims to evaluate the optimal lengthening system for treating post-traumatic long bone deformity.

METHODS

The systematic review was conducted in accordance with PRISMA guidelines. PUBMED, EMBASE, CINAHL, and the Cochrane Library were searched for comparative studies of lengthening techniques among adult patients with axial deformities. Studies were screened and data extracted in duplicate. Treatment groups were pooled into external fixation (EF) alone, combined internal and external fixation (CIF), and mechanical lengthening nail (MLN). Outcomes were mean lengthening achieved, lengthening index, and reported complications.

RESULTS

Thirteen studies with 725 patients (mean age: 29.6 years, 74% male) were included. Nearly all of the studies were either prospective or retrospective cohort studies (n = 12), with one randomized controlled trial of moderate study quality. The mean limb lengthening achieved, lengthening index, and rate of reoperation were similar among the MLN, EF, and CIF groups.

CONCLUSION

The purported decreased the duration of lengthening and the risk of reoperation associated with MLNs was not demonstrated in this review. Patients with post-traumatic leg length deformities remain a challenging patient population to treat, with intervention being associated with high rates of infectious complications and need for revision operations.

Leg Length Discrepancy- Treatment Indications and Strategies

BACKGROUND

Many people have leg-length discrepancies of greater or lesser severity. No evidence-based studies on the need for treatment are currently available.

METHODS

This review is based on publications retrieved by a selective search in the PubMed database, as well as on published recommendations from Germany and abroad and on the authors' own clinical experience.

RESULTS

If the two legs are of different lengths, this is generally because one leg is too short. It is debated whether leg-length discrepancy causes pain or long-term musculoskeletal disturbances. A direct connection to back pain is questionable, but a mildly elevated incidence of knee arthritis seems likely. The evidence base on the indications for treatment of leg-length discrepancy is poor; only informal consensus recommendations are available. There are a wide variety of conservative and surgical treatment options. The final extent of a leg-length discrepancy first noted during the growing years can be estimated with predictive algorithms to within 2 cm. The treatments that can be considered include a shoe insert, a high shoe, or an orthosis, surgically induced slowing of growth by blockade of the epiphyseal plates around the knee joint, or leg lengthening with osteotomy and subsequent distraction of the bone callus with fully implanted or external apparatus. Changes in leg length exert marked mechanical stress on the soft tissues. If the predicted leg-length discrepancy exceeds 5 cm, initial leg-lengthening treatment can already be considered during the patient's growing years.

CONCLUSION

It must be discussed with each patient individually whether the treatment should be conservative or surgical. The extent of the discrepancy is not the sole determining factor for the mode of treatment. The decision to treat is always elective.

Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails

Background

Intramedullary limb lengthening has become an accepted concept in reconstructive surgery, but as yet comparative clinical studies are missing. We compared the complications and effectiveness of two types of intramedullary limb lengthening devices (ISKD®; Fitbone®).

Materials and methods

In a retrospective series of 278 consecutive patients with internal limb lengthening, we found 17 matching pairs in terms of predefined matching parameters (group I with ISKD® and group II with Fitbone®). The surgeries were all performed with the same technique and managed with equivalent pre- and postoperative treatment protocols. The performance of the implants was evaluated using the distraction index and the weight-bearing index. Complications were rated according to Paley's classification for external lengthening.

Results

The distraction index in group I (ISKD®) was 0.99 mm/day (range 0.55-1.67) and in the group II (Fitbone®) 0.55 mm/day (range 0.14-0.92) (p value = 0.001). The mean weight-bearing index differed between group I and group II from 32.0 day/cm (range 16.4-64.0) to 51.6 day/cm (25.8-95.0) (p value = 0.001). There were 17 recorded incidents in group I and 19 in group II during lengthening.

Conclusion

Specific technical handicaps of the two systems, such as the so-called runaway of the ISKD® and backtracking of the Fitbone® nails seem to result in different distraction index and weight-bearing index. Further comparative studies might induce technical progress in intramedullary limb lengthening.

How to cite this article

Thaller PH, Frankenberg F, Degen N, et al. Complications and Effectiveness of Intramedullary Limb Lengthening: A Matched Pair Analysis of Two Different Lengthening Nails. Strategies Trauma Limb Reconstr 2020;15(1):7-12.

Repeated intramedullary stabilization following failed telescopic nail lengthening - An appropriate treatment strategy

Externally magnetic-controlled intramedullary telescopic nails for bone lengthening have recently gained popularity due to many advantages when compared to more traditional lengthening methods. Patients requiring lengthening often present with a clinical history of previous multiple surgeries increasing the risk for complications of further procedures. However, studies regarding the treatment of complications following implantation of these devices remain scarce in literature. Therefore, we report our experience with revision surgery after lengthening with a telescopic intramedullary lengthening nail. In 6 out of 20 cases (30%) of lower limb lengthening for leg length discrepancy revision surgery was necessary. Two revisions were necessary due to nail breakage while the other 4 cases required a secondary procedure for non-union. In all cases, revision surgery included standard intramedullary locking nailing with additional autologous bone grafting. The median interval between index and revision surgery was 11.5 months (range 2-15 months). Satisfying clinical results, the intended extend of lengthening and bony consolidation was observed in all 6 patients. We conclude that revision surgery using an intramedullary locking nail with autologous bone grafting after failed telescopic nail-based lengthening represents an useful salvage procedure in these cases.

Lower limb lengthening over an intramedullary nail: a long-term follow-up study of 28 cases

Background

Limb lengthening using an external fixator requires a long period of external fixation and may be associated with several complications such as axial deformity, fracture of the regenerated bone, and joint stiffness. With the goal of reducing the time of external fixation as well as some of these complications, we performed femoral or tibial lengthening over an intramedullary nail, according to Paley’s technique, in 28 patients, followed up after a mean period of 8 years.

Materials and methods

Twenty-eight patients treated for lower limb discrepancy by limb lengthening over an intramedullary nail were reviewed from 5 to 11 years after healing of regenerated bone. There were 20 femurs and 8 tibiae, with average age at surgery of 14.2 years and average length inequality of 6.1 cm for femurs and 5.3 cm for tibiae.

Results

The mean lengthening was 5.8 cm for femurs and 4.8 cm for tibiae. The mean period of radiographic consolidation of the regenerated bone was 6 months for femoral lengthening and 4.5 months for tibial lengthening. At follow-up, we observed 8 excellent results, 15 good results, 4 fair results, and 1 poor result, based on Paley’s evaluation criteria. The main complications were one deep infection, one nonunion of the distracted segment, one breakage of the distal fiche of the external fixator, and one breakage of both distal locking screws of the intramedullary nail.

Discussion

We believe that limb lengthening over an intramedullary nail still represents a good method to treat limb length discrepancy because it reduces the time of external fixation, prevents axial deformities and fractures of regenerated bone, and allows early rehabilitation. The new intramedullary lengthening nails, which theoretically are the ideal device for treating limb length inequality, are still very expensive and need longer follow-up for definitive evaluation.

Level of evidence

4.

Relevant advances in bone lengthening research: a bibliometric analysis of the 100 most-cited articles published from 2001 to 2017

This study aimed to assess the scientific production of bone lengthening research by identifying the most-cited papers. All articles including the term 'bone lengthening' published between 2001 and 2017 were retrieved through the Web of Science database. The 100 most-cited articles on bone lengthening included a total of 4244 citations, with 414 (9.7%) citations in 2017. There was an average of 249.6 citations per year. The articles predominantly addressed biomechanics and bone formation (38). Different surgical techniques, including intramedullary nail (14), Ilizarov (nine), intramedullary skeletal kinetic distractor (ISKD) (six), Taylor spatial frame (6), the PRECICE device (three), and lengthening and submuscular locking plate (three), were the second most-studied topic. Most studies were therapeutic (58), whereas 30 studies were experimental investigations using animal models. Among the clinical studies, case series were predominant (level of evidence IV) (57). This study presents the first bibliometric analysis of the most relevant articles on bone lengthening. The list is relatively comprehensive in terms of identifying the top issues in this field. However, the most influential clinical studies have a poor level of evidence, although a slight tendency toward a better level of evidence has been observed in more recent years.

Cost Comparison of Femoral Distraction Osteogenesis With External Lengthening Over a Nail Versus Internal Magnetic Lengthening Nail

INTRODUCTION

Femoral lengthening is performed by distraction osteogenesis via lengthening over a nail (LON) or by using a magnetic lengthening nail (MLN). MLN avoids the complications of external fixation while providing accurate and easily controlled lengthening. However, the increased cost of implants has led many to question whether MLN is cost-effective compared with LON.

METHODS

A retrospective review was performed comparing consecutive femoral lengthenings using either LON (n = 19) or MLN (n = 39). The number of surgical procedures, time to union, and amount of lengthening were compared. Cost analysis was performed using both hospital and surgeon payments. Costs were adjusted for inflation using the Consumer Price Index.

RESULTS

No difference was observed in the length of femoral distraction. Patients treated with MLN underwent fewer surgeries (3.1 versus 2.1; P < 0.001) and had a shorter time to union (136.7 versus 100.2 days; P = 0.001). Total costs were similar ($50,255 versus $44,449; P = 0.482), although surgeon fees were lower for MLN ($4,324 versus $2,769; P < 0.001).

DISCUSSION

Although implants are more expensive for MLN than LON, this appears to be offset by fewer procedures. Overall, the two procedures had similar total costs, but MLN was associated with a decreased number of procedures and shorter time to union.

LEVEL OF EVIDENCE

III.

Novel Surgical Approach to Segmental Bone Transport Using a Magnetic Intramedullary Limb Lengthening System

Posttraumatic bone defects (BDs) remain a difficult complication for orthopaedic surgeons. Surgical goals in these reconstructive cases are to create stable limb fixation, maintain limb length, and provide adequate soft-tissue coverage. Historically, surgical approaches in these cases have required the use of an external fixator, which is associated with several postoperative complications. A plate-assisted bone segment transport (PABST) technique using a magnetic limb lengthening system eliminates the need for an external fixator and is effective for these reconstructive cases. A 51-year-old male patient presented as a category I trauma after a motorcycle collision. Osseous injury was defined as Gustilo-Anderson type IIIB distal tibia and fibula fracture (AO 42-C2). After fixation failure, the PABST technique was performed using a magnetic intramedullary limb lengthening system. Radiographic union was achieved 18 months postoperatively. This innovative surgical technique is effective in treating posttraumatic BDs without the need for limb shortening or the use of an external fixator. PABST has the potential to decrease postoperative complications in BD reconstructive cases using all-internal technology designed for limb lengthening. PABST, in this instance, uses a magnetic intramedullary nail that is controlled with a hand-held external remote to allow for precise, adjustable, and bidirectional bone segment transport.

Regenerative medicine in lower limb reconstruction

Bone is a highly specialized connective tissue and has a rare quality as one of the few tissues that can repair without a scar to regain pre-injury structure and function. Despite the excellent healing capacity of bone, tumor, infection, trauma and surgery can lead to significant bone loss requiring skeletal augmentation. Bone loss in the lower limb poses a complex clinical problem, requiring reconstructive techniques to restore form and function. In the past, amputation may have been the only option; however, there is now an array of reconstructive possibilities and cellular therapies available to salvage a limb. In this review, we will evaluate current applications of bone tissue engineering techniques in limb reconstruction and identify potential strategies for future work.

A Comparison of Femoral Lengthening Methods Favors the Magnetic Internal Lengthening Nail When Compared with Lengthening Over a Nail

BACKGROUND

Bone lengthening with an internal lengthening nail (ILN) avoids the need for external fixation and requires one less surgical procedure than lengthening over a nail (LON). However, LON has been shown to be superior to femoral internal lengthening using a mechanical nail. The magnetic ILN, a remote-controlled and magnet-driven device, may have overcome the weaknesses of earlier internal lengthening technology and may be superior to LON.

QUESTIONS/PURPOSES

(1) Is the magnetic ILN more accurate than LON for femoral lengthening? (2) Does the magnetic ILN demonstrate more precise distraction rate control than LON? (3) Does the magnetic ILN result in faster regenerate site healing, with more robust callus, than LON? (4) Does the magnetic ILN result in fewer complications, including impediments to knee motion, than LON?

METHODS

We conducted a retrospective comparison of the records and radiographs of 21 consecutive patients with 22 femoral lengthenings using LONs and 35 consecutive patients with 40 femoral lengthenings using remote-controlled magnetic ILNs. Primary outcomes measured included accuracy, distraction rate precision, time to bony union, final knee range of motion, regenerate quality, and complications. The minimum follow-up times for the LON and ILN cohorts were 13 and 21 months, respectively.

RESULTS

Patients treated with ILN had a lower post-treatment residual limb-length discrepancy (0.3 mm) than those treated with LON (3.6 mm). The rate of distraction was closer to the goal of 1 mm/day and more tightly controlled for the ILN cohort (1 mm/day) than that for the LON group (0.8 mm/day; SD, 0.2). Regenerate quality was not significantly different between the cohorts. Bone healing index for ILN was not statistically significant. Time to union was shorter in the ILN group (3.3 months) than that in the LON group (4.5 months). A lower percentage of patients experienced a complication in the ILN group (18%) than in the LON group (45%). Knee flexion at the end of distraction was greater for ILN patients (105°) than that for LON patients (88.8°), but this difference was no longer observed after 1 year.

CONCLUSIONS

Femoral lengthening with magnetic ILN was more accurate than with LON. The magnetic ILN comports the additional advantage of greater precision with distraction rate control and fewer complications. Both techniques afford reliable healing and do not significantly affect knee motion at the final follow-up. The magnetic ILN method showed no superiority in regenerate quality and healing rate.

Total hip arthroplasty and femoral nail lengthening for hip dysplasia and limb-length discrepancy

The application of distraction osteogenesis through the use of magnet-operated, remote-controlled intramedullary lengthening continues to provide new opportunities for accurate limb equalization. While limb-length discrepancy and deformity can be addressed by total hip arthroplasty alone, the magnitude of correction is limited by the soft-tissue envelope and complications such as sciatic nerve palsy. This 3-patient case series presents the combination of staged ipsilateral total hip arthroplasty and retrograde intramedullary femoral nail lengthening for the correction of both deformity and limb-length discrepancy. Our results report leg-length equalization, independent ambulation without assistive devices, and excellent bone and functional outcomes without complications, demonstrating that this combined technique can be used to achieve targeted lengthening and deformity correction.

Mechanical failure of a femoral lengthening nail: a case report

Background

This case report describes the mechanical failure of a femoral lengthening nail in order to allow early recognition and prevent its occurrence.

Case presentation

A femoral lengthening nail was used to achieve goal distraction length over eight weeks and sustained a mechanical failure during progressive weightbearing. Re-distraction was attempted with subsequent non-weight-bearing status. Although the patient was not able to attain the original goal length, radiographs demonstrated stable shortening of the patient's right lower extremity along with early signs of incomplete regenerate bone. She eventually received exchange nailing with bone graft.

Conclusion

Post-operative protocol and weight-bearing status should be further researched and standardized after re-evaluating the mechanical stiffness of the intramedullary nail construct.

Simultaneous Acute Femoral Deformity Correction and Gradual Limb Lengthening Using a Retrograde Femoral Nail: Technique and Clinical Results

INTRODUCTION

Patients with limb-length discrepancies often have concomitant deformity. We describe the outcomes of acute, fixator-assisted deformity correction with gradual lengthening using the retrograde femoral Precice nail (NuVasive).

METHODS

We analyzed a retrospective series of 27 patients in whom an external fixator was combined with a Precice nail to correct angular or rotational deformity and limb-length discrepancy. The fixator was applied temporarily to restore normal alignment. The Precice nail was inserted and locked in place to hold the correction, with gradual restoration of limb length.

RESULTS

The 27 patients (mean age, 28 years) had a mean follow-up of 13 months. Secondary deformities were mainly valgus (15 patients) and varus (10 patients). Postoperatively, 93% of patients had correction of limb length to within 3 mm of the discrepancy (mean lengthening, 30 mm). Mechanical axis deviation was corrected to within 8 mm of neutral (ie, zero) in 81% of patients. The mechanical lateral distal femoral angle was corrected to a mean of 88° postoperatively. Final Association for the Study and Application of Methods of Ilizarov (ASAMI)-Paley scores were excellent for 96% of patients.

DISCUSSION

The use of intramedullary lengthening nails has revolutionized the field of limb lengthening. The results of our study show that a retrograde femoral Precice nail can be used safely and accurately to correct both limb-length discrepancy and deformity with minimal complications. The benefits of using this implant include the ability to maintain knee range of motion during the lengthening process. Rapid bone healing allows a relatively fast return to weight-bearing ambulation.

CONCLUSIONS

The Precice nail was effectively used to correct both limb-length discrepancy and deformity, with excellent overall outcomes. This surgical technique may help avoid the complications that can occur with prolonged postoperative use of an external fixator.

LEVEL OF EVIDENCE

Level IV retrospective study.

Late treatment of obstetrical brachial plexus palsy by humeral rotational osteotomy and lengthening with an intramedullary elongation nail

To date, all the authors who have recommended external rotation osteotomy (ERO) in the late treatment of obstetrical brachial plexus palsy (OBPP), have neglected upper limb length discrepancy, which is an another sequelae of OBPP. In this paper, a new technique is reported for the late treatment of OBPP patients with upper limb length discrepancy, in which both humeral external rotation osteotomy (ERO) and lengthening are applied with an intramedullary elongation nail. With this technique, upper limb function is improved through re-orientation of the shoulder arc to a more functional range, and further improvements will be seen in the appearance of the upper limb with the elimination of length discrepancy. It is also advocated that there is a potentiating effect of the humeral lengthening on shoulder movements gained by ERO when the osteotomy is applied above the deltoid insertion, as this allows more lateralized placement of the deltoid insertion.

A Comparison of the Device-Related Complications of Intramedullary Lengthening Nails Using a New Classification System

The purpose of this study was to understand the pros and cons of the lengthening nails which have their own mechanical mechanism; we propose a classification for “device-related complications” arising from mechanical properties of the nail itself. From March 2010 to March 2014, 115 segments of lower limb lengthening were performed using intramedullary lengthening nails (35 ISKD, 34 PRECICE1, and 46 PRECICE2). Device-related complications were sorted into three categories according to a new classification: distraction control-related (type I), stability related (type II), and other device-related (type III); these were subdivided using Paley's concept of problems (a), obstacles (b), and sequel (c). Most common complications were distraction mechanism issues (type I) in ISKD and mechanical strength related ones (type II) in PRECICE1 and PRECICE2. Sixty percent (21/35) of ISKD had device-related problems. In PRECICE1 group, 8.8% (3/34) had device-related problems, and 8.8% (3/34) showed device-related obstacle. In PRECICE2, forty-four percent (20/46) had device-related problems. In conclusion, a new classification showed more clearly the differences of mechanical characteristics of different nails. The most essential thing of future lengthening nail development is minimizing the types I and II complications. Further study is necessary to compare the mechanical strength and stability of lengthening nails.

Retrograde magnetic internal lengthening nail for acute femoral deformity correction and limb lengthening

INTRODUCTION

The Precice magnetic internal lengthening intramedullary nail is being used with great success in femur lengthening and deformity correction with a retrograde approach. Areas Covered: Our personal history of limb lengthening and the Precice nail will be reviewed. Several technical aspects are discussed including design updates, pre operative planning, selection of nail length, the use of blocking screws and intra operative temporary external fixation, osteotomy practice, post operative management, and cost analysis. Expert Commentary: The phenomenal bone healing ability for the retrograde Precice nail after femoral osteotomy for lengthening, even after acute deformity correction, is recognized throughout the growing body of scientific publications on this topic. The few failures that have occurred appear to be attributable to excessive loading of the femur and implant during a vulnerable time of bone healing. Further studies with more uniform outcome criteria need to be conducted to better standardize user's experiences. The higher one time cost of the implant is offset by the reduced number of surgeries needed when compared with the gold standard of lengthening-over-nail-technique, and we suspect that patients return to work sooner due to the ability to wear normal clothing and the reduction in pain throughout the entire lengthening process.

Circular hexapod external fixation for periprosthetic tibial fracture

A poor soft tissue envelope often accompanies periprosthetic tibia fracture around a well-fixed total knee arthroplasty and the tibial stem leaves little room for screw fixation. This article describes the practicability and effectiveness of a novel surgical technique using circular hexapod external fixation, in patients with this clinical scenario. It was applied for fixation of periprosthetic tibia fracture in 2 patients. Contact between the external fixation pins and the prosthesis was avoided. Using a web-based software program, a gradual reduction in all planes was achieved. Adequate fixation, stability, reduction, and quick healing were obtained in the 2 cases, with minimal complications. The patients returned to their activity level a few months after external fixation removal.

Adult Posttraumatic Reconstruction Using a Magnetic Internal Lengthening Nail

A new generation of internal lengthening nail is now available that has reliable remote-controlled mechanisms. This allows accurate and well-controlled distraction rate and rhythm, and early clinical results have been very positive. In this article, 2 posttraumatic cases are presented that illustrate deformity correction and lengthening using the internal lengthening nail. Surgical planning and adjuvant techniques of fixator-assisted nailing and the use of blocking screws are discussed.

The role of the intramedullary implant in limb lengthening

Limb lengthening is now an accepted practice in orthopaedic surgery. The principles of distraction osteogenesis have become well established with the use of external fixators, utilizing both monolateral and ring fixators. Corticotomy technique, frame stability, lengthening rate and rhythm all contribute to the formation of bone regenerate and tissues. Complications are however common including pin-site infection, soft tissue tethering from the pins and wires resulting in pain, regenerate deformity from soft tissue forces or fracture following frame removal and patient intolerance of the frames during treatment. Surgical techniques have changed to try and minimise these complications. The use of intramedullary nails have been used in conjunction with an external fixator or inserted after lengthening has been achieved, to reduce fixator time and prevent regenerate deformity. Implant innovation has led to the production of intramedullary lengthening nails. The initial devices used ratchet mechanisms with rotation of the bone fragments to achieve lengthening (Bliskunov, Albizzia and ISKD). More accurate control of lengthening and a reduction in pain, resulting from the manual rotation of the leg required to achieve the ratchet progression, was achieved by the use of a transcutaneous electrical conduit powered by external high frequency electrical energy (Fitbone). The most recent implant uses an external remote controller which contains two neodymium magnets. These are placed over the nail on the skin and rotate which in turn rotates a third magnet within the intramedullary nail (Precice). This magnet rotation is converted by a motor to extend or retract the extendible rod. There are multiple nail sizes and lengths available, and early results have shown accurate control with few complications. With such promising outcomes the use of this lengthening intramedullary nail is now recommended as the implant of choice in femoral lengthening. This article is an historical account of the intramedullary device and the impact on limb lengthening.

PRECICE® magnetically-driven, telescopic, intramedullary lengthening nail: pre-clinical testing and first 30 patients

Introduction: Femoral/tibial lengthening with a telescopic, magnetically-powered, intramedullary nail is an alternative to lengthening with external fixation.

Methods: Pre-clinical testing was conducted of the PRECICE in a human cadaver. A retrospective review of the first 30 consecutive patients who underwent unilateral lengthening was also conducted. Nail accuracy was obtained by comparing the amount of nail distraction to the final bone length achieved at the end of the distraction process. Relative standard deviation of accuracy was used to calculate nail precision.

Results: Devices performed successfully in a human cadaver. Thirty consecutive patients (10 females, 20 males; mean age, 23 years) with limb length discrepancy (LLD) were followed an average of 19 months (range, 12–24 months). Etiology included congenital shortening (14), posttraumatic deformities (7), Ollier disease (3), osteosarcoma resection (1), prior clubfoot (2), hip dysplasia (1), post-septic growth arrest of knee (1), and LLD after hip arthroplasty (1). Twenty-four femoral and eight tibial nails were implanted. Mean preoperative lengthening goal was 4.4 cm (range, 2–6.5 cm); mean postoperative length achieved was 4.3 cm (range, 1.5–6.5 cm). Average consolidation index was 36.4 days/cm (range, 12.8–113 days/cm). Mean nail accuracy was 97.3% with a precision of 92.4%. Average preoperative and 12-month postoperative Enneking scores were 21.5 and 25.3 (p < 0.001), respectively. The preoperative and 12-month postoperative SF-12 physical and mental component scores were not statistically different. Nine complications (nine limb segments) resolved: two partial femoral unions, two suspected deep vein thrombosis (DVT), one delayed tibial union, one fibular nonunion, one peroneal nerve irritation, one knee joint subluxation, and one confirmed DVT. Twenty-nine (91%) of 32 limb segments achieved successful bone healing without revision surgery.

Discussion: Limb lengthening with PRECICE is reliable, but larger trials with longer follow-up will reveal limitations. Implantable nails prevent problems associated with external fixation, such as muscle tethering and pin-site infections.

Femoral lengthening in children and adolescents

Current lengthening techniques are still based on the Ilizarov method and the concept of callotasis. Research and progress in medical devices have led to constant improvement in results. Hexapod fixators allow more precise correction of complex deformities, with shorter learning curve. Associating lengthening by external fixation (EF) to internal fixation (K-wire, intramedullary nail or locking plate) has reduced EF times and complications rates, while improving anatomic and functional results. Lengthening nails provides faster recovery of range of motion and return to activity during lengthening and consolidation, with better psychological tolerance. Lengthening with deformity correction by retrograde nailing has no impact on consolidation. Monolateral EF is a reliable and easy-to-implement technique that is well tolerated by patients. Association to internal fixation gives promising results. Bone healing solidity assessment on plain X-ray is highly subjective, with wide inter- and intra-observer variation; bone mineralization is better assessed in terms of pixel-value ratio (PVR: ratio of pixel value of regenerate to adjacent bone) on picture archiving and communication system (PACS) digitized radiographs, providing objective assessment of callus solidity.

Femur lengthening with monoplanar external fixator associated with locked intramedullary nail

OBJECTIVE

This study aimed to demonstrate that the lengthening technique of an external fixator associated with locked intramedullary nail is an efficient method that decreases the duration of the external fixation and improves the rehabilitation period.

METHODS

From January of 2005 to May of 2014, 31 patients with mean lower limb discrepancy of 5.31 cm were treated. The etiologies of the deformity were femur fracture sequelae, infection, hip development dysplasia, polio, and congenital short femur.

RESULTS

The mean duration of external fixation was 2.47 months (external fixation index of 16.15 days per cm). The mean time for bone healing was 6.66 months (consolidation index 43 days per cm). Initial mean knee range of motion was -1° to 100°, progressing to 0°-115° at the end of treatment. The complications observed were incomplete osteotomies, hip subluxation, broken fixator, decreased knee range of motion, and need for locking screw removal.

CONCLUSION

Femur lengthening with a monoplanar external fixator associated with locked intramedullary nail allowed for a shorter period of external fixation use, better protection for the regenerated bone tissue, and early rehabilitation with possible complications.

Pitfalls in automatic limb lengthening - First results with an intramedullary lengthening device

BACKGROUND

The treatment of leg length discrepancy and deformities has become more common over the last few decades due to newly developed implants. Lengthening using fully implantable intramedullary nails provides many advantages; however, only little data is available. Therefore, we aimed to determine: (1) safety of the implant, (2) the complication rate and (3) functional outcome after magnetic driven intramedullary bone lengthening with a telescopic implant.

HYPOTHESES

Automatic bone lengthening with intramedullary nails provide good short-term outcome.

PATIENTS AND METHODS

Ten patients with limb length discrepancy of lower extremity, treated with an Ellipse PRECICE^® nail, were included in this retrospective follow-up study. The mean limb length discrepancy was 4.7cm (range: 2.5-7.0cm).

RESULTS

In all patients, limb lengthening goals were reached within a range of ±0.5cm after a mean time of 53 days. However, in 2 patients, mechanical failures with unintended shortening were observed. In a further patient nail breakage occurred. Overall, 7 patients presented with complications during the follow-up period.

DISCUSSION

The PRECICE^® nail represents a new, fully implantable, magnetically driven device for limb lengthening. However, due to a high rate of complications, a close follow-up is necessary to identify early implant failures and to avoid severe adverse outcomes.

LEVEL OF EVIDENCE

Retrospective follow-up study, case series, level IV.

Outcomes following femoral lengthening

Aims

Patients undergoing femoral lengthening by external fixation tolerate treatment less well when compared to tibial lengthening. Lengthening of the femur with an intramedullary device may have advantages.

Patients and Methods

We reviewed all cases of simple femoral lengthening performed at our unit from 2009 to 2014. Cases of nonunions, concurrent deformities, congenital limb deficiencies and lengthening with an unstable hip were excluded, leaving 33 cases (in 22 patients; 11 patients had bilateral procedures) for review. Healing index, implant tolerance and complications were compared.

Results

In 20 cases (15 patients) the Precice lengthening nail was used and in 13 cases (seven patients) the LRS external fixator system. The desired length was achieved in all cases in the Precice group and in 12 of 13 cases in the LRS group. The mean healing index was 31.3 days/cm in the Precice and 47.1 days/cm in the LRS group (p < 0.001). This was associated with an earlier ability to bear full weight without aids in the Precice group. There were more complications with LRS lengthening, including pin site infections and regenerate deformity. Implant tolerance and the patients’ perception of the cosmetic result were better with the Precice treatment.

Conclusion

Femoral lengthening with the Precice femoral nail achieved excellent functional results with fewer complications and greater patient satisfaction when compared with the LRS system in our patients. Cite this article: Bone Joint J 2016;98-B:1382–8.

Lengthening Over an Existing Intramedullary Nail In Cases of Post-traumatic Femoral Shortening. Technical Note. Case Series Study

Background:

Intramedullary (IM) nailing is the method of choice for the treatment of most femoral shaft fractures. However, despite successful solid union, great initial fracture comminution can lead to significant leg length discrepancy affecting normal gait mechanics. Femoral osteotomy and distraction osteogenesis over the pre-existing IM nail could restore this limb inequality.

Methods:

Five patients with an average post-traumatic femoral shortening of 3.83 cm were presented in our department with the nail in situ. Limb lengthening was achieved with the application of a distal hybrid external rail frame over the pre-existing nail. We assumed that the choice of a distal external fixator ring with wires could facilitate the procedure and minimize the possibility of friction–contact problems with the large diameter nail.

Results:

The amount of length discrepancy, calculated preoperatively, was restored in all patients. The mean time in frame was 57.6 days and the external fixator index 16.978 d/cm. The mean time of total healing was 152.6 days and the average bone-healing index 44.9d/cm. No deep infection or hardware loosening was observed. One superficial pin track infection was treated successfully with oral antibiotics.

Conclusion:

This technique utilizes the principles and advantages of lengthening over an IM nail, avoids the necessity of nail removal and minimizes the complication rates and the overall time for complete recovery.

Lengthening over nails using the double plate system ONAS-DPS

Stable insertion of large Schanz screws behind an intramedullary (IM) nail when lengthening over nails (LON) may be difficult due to the limited bone stock. Additionally, the highly probable contact between the screws and IM nail (which is difficult to avoid) increases the likelihood of infection spreading from the skin via Schanz screws directly to the IM nail. A new device for LON has been developed. Instead of inserting Schanz screws from the external fixator beside the IM nail (as in standard LON), a system of two overlaying plates was constructed. Schanz screws can be fixed to the plates without entering the bone. The plates are fixed to the bone using four angle stability screws. The holes in the plates offer stabile fixation for a chosen angle under which the screw is positioned through the cortical bone. Using the new system there is no need to place Schanz screws behind the IM nail. Instead, Schanz screws pass to the plate and not through the bone. The new system for elongation over IM nail is called “Over Nail Angle Stability-Double Plate System” (ONAS-DPS) [Antolič V (2013) Modular side device with an intramedullary nail for guiding a bone during its lengthening. World Intellectual Property Organization. International Publication number: WO 2013/176632 A1].

Premature Consolidation with Resultant Implant Failure Using PRECICE Femoral Nail Lengthening: A Case Report

CASE

Posttraumatic limb-length discrepancies secondary to femoral malunion can be treated with a variety of external or internal lengthening systems. The PRECICE nail is an intramedullary device featuring an external remote control to activate a magnetically driven internal distraction mechanism. While this intramedullary system avoids the soft-tissue complications common to external lengthening, it has unique mechanisms of failure that are difficult to diagnose and that require a systematic approach.

CONCLUSION

In this case report, we describe a failure to lengthen with the PRECICE femoral nail and the subsequent steps taken to determine the root cause. We believe that this failure represents the first reported case of malfunction of the PRECICE femoral nail distraction mechanism since its 2013 redesign.