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

Total Hip Replacement and Femoral Nail Lengthening for Hip Dysplasia and Limb Length Discrepancy: A Literature Review

Developmental dysplasia of the hip (DDH) is a serious condition resulting in inadequate acetabular development, distorted bone configuration, and substantially altered hip biomechanics. An extensive leg length discrepancy (LLD) is commonly encountered in such cases, making a total hip arthroplasty (THA) procedure extremely challenging. Although good results in terms of patients' satisfaction, implant survival rates and overall improved quality of life have been reported, complication rates are considerably higher than primary THA procedures performed for idiopathic osteoarthritis. Reconstructing a dysplastic hip arthrosis and equalizing a preexisting LLD is a technically demanding procedure that is associated with significant bone and soft tissue complications. Intramedullary lengthening through motorized nails has become increasingly popular to address difficult cases with extensive LLD following THA in recent years. However, limited data on femoral lengthening procedures implemented following THA are available considering complications, radiological results, and patient-reported outcomes following staged THA and subsequent femoral lengthening using a femoral magnetically-driven intramedullary lengthening nail. We performed a literature review of the past 10 years in PubMed using the terms neglected hip dislocation, DDH, THA, and intramedullary lengthening nail as keywords. A total amount of eight cases addressing LLD through a telescoping intramedullary nail following THA in DDH have been reported in recent literature. All eight patients underwent primary THA for DDH followed by the implantation of the intramedullary lengthening nail. The mean THA was lengthened by 28.9 mm (from 13.0 to 45.0). The mean time for nail implantation after THA was 11.1 months (from 3.5 to 21). The mean time for lengthening per day through the nail was 0.94 mm (from 0.65 to 1.0) from 26 days to 70 days, and the mean lengthening through the nail was 37.6 mm (from 24.0 to 70.0). Good union and consolidation rates were reported by the authors, while there were no complications. The intramedullary distraction osteogenesis method with a telescopic rod can be an effective method to manage leg length discrepancies while avoiding soft tissue complications in challenging cases of DDH.

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.

How Much Does Paediatric Femoral Lengthening Cost? A Cost Comparison between Magnetic Lengthening Nails and External Fixators

Aim

Motorised intramedullary lengthening nails are considered more expensive than external fixators for limb lengthening. This research aims to compare the cost of femoral lengthening in children using the PRECICE magnetic lengthening nail with external fixation.

Methods

Retrospective analysis of 50 children who underwent femoral lengthening. One group included patients who were treated with PRECICE lengthening nails, the other group included patients who had lengthening with external fixation. Each group included 25 patients aged between 11 and 17 years. The patients in both groups were matched for age. Cost analysis was performed following micro-costing and analysis of the used resources during the different phases of the treatments.

Results

Each group's mean patient age was 14.7 years. Lengthening nails were associated with longer operative times compared with external fixators, both for implantation and removal surgery (p-values of 0.007 and < 0.0001, respectively). Length of stay following the implantation surgery, frequency of radiographs and frequency of outpatient department appointments were all lower with lengthening nails. The overall cost of lengthening nails was £1393 more than external fixators, however, this difference was not statistically significant (p-value = 0.088).

Conclusion

The difference in the mean costs between femoral lengthening with lengthening nails versus external fixators was not statistically significant. Further research to review the effectiveness of the devices and the quality of life during the lengthening process is crucial for robust health economic evaluation.

How to cite this article

Hafez M, Nicolaou N, Offiah A, et al. How Much Does Paediatric Femoral Lengthening Cost? A Cost Comparison between Magnetic Lengthening Nails and External Fixators. Strategies Trauma Limb Reconstr 2023;18(1):16-20.

Trends and Practices in Limb Lengthening: An 11-year US Database Study

Aim

Over the past couple of decades, limb lengthening has evolved to encompass various implants and techniques. The purpose of this study was to (1) determine trends in the utilisation of various limb lengthening techniques for the femur and tibia in the United States, (2) determine trends in 1-year readmission rate following limb lengthening procedures and (3) to study the relationship of limb lengthening implant used and payment method used with the underlying diagnosis associated with limb shortening.

Materials and methods

Inpatient data were acquired using the Healthcare Cost and Utilisation Project (HCUP) database from 2005 to 2015 from seven states in the United States. Patients with an International Classification of Diseases (ICD)-9 code for limb lengthening of the femur or tibia were included. A total of 2,563 patients were included. Data were analysed using descriptive statistics, and chi-square test was used for comparison of subcategories. Linear regression analysis was used to examine trends over time.

Results

There was a strong linear trend towards increasing proportional use of internal lengthening of the femur from 2011 to 2015 (R2 = 0.99) with an increase of 10.2% per year. A similar trend towards increasing proportional use of internal lengthening of the tibia was seen from 2011 to 2015 (R2 = 0.87) with an increase of 4.9% per year. There was a moderate correlation showing a decrease in readmission rate of 1.07% per year from 2005 to 2015 (R2 = 0.55). Patients with short stature had increased use of internal lengthening and self-payment compared to patients with congenital, post-traumatic or other diagnoses.

Conclusion

There was increasing use of internal lengthening techniques from 2011 to 2015. Patients with short stature had higher use of internal lengthening technique and self-pay for payment method.

Clinical significance

Intramedullary devices have seen increasing use for limb lengthening procedures. Lengthening technique and payment method may differ by underlying diagnosis.

How to cite this article

Mittal A, Allahabadi S, Jayaram R, et al. Trends and Practices in Limb Lengthening: An 11-year US Database Study. Strategies Trauma Limb Reconstr 2023;18(1):21-31.

No osteolysis at the telescopic junction of 128 FITBONE lengthening nails

BACKGROUND

Motorized lengthening nails are the treatment standard for bone lengthening of the lower limbs. However, bony changes namely osteolysis and periosteal hypertrophy have been described after certain type of magnetically driven lengthening nails. The aim of this study was to estimate the proportion rate of radiological bone abnormalities of Fitbone TAA femoral or tibial lengthening nails with a minimum follow-up time of 1 year.

HYPOTHESIS

The bone surrounding the telescopic junction of Fitbone lengthening nails does not exhibit osteolysis or periosteal reactions. The bone surrounding the locking screws exhibits cortical hypertrophy.

PATIENTS AND METHODS

Single-centre retrospective case series of patients treated with a Fitbone nails with a minimum follow-up of 1 year after implantation. Standard orthogonal radiographs were obtained postoperatively, weekly during the distraction phase, and then monthly for 6 months, and before removal of the equipment. We looked for bone abnormalities at the telescoping junction of the nail and at the locking screws before removal.

RESULTS

In total, 101 patients (58 males, 43 females) with a mean age of 21 years (range: 11.8-53.5) had 128 (101 femoral and 27 tibial) limb lengthening nails implanted between 2010 and 2021. The mean follow-up period was 925 days (range: 371-3587). The mean lengthening was 4.7cm (range: 1.5-8.0). No bones exhibited focal osteolysis or periosteal reactions at the telescopic junction of the lengthening nail. Cortical hypertrophy at the locking screws was observed in significantly more Fitbone nails than previously reported, i.e., 101/128 (79%).

DISCUSSION

Neither focal osteolysis, nor periosteal reactions were observed at the bone surrounding the telescopic junction of 128 Fitbone lengthening nails. Cortical hypertrophy around the single diaphyseal locking screw was observed in 101/128 (79%) of the cases. These absences of osteolytic changes after long term observation are reassuring for both surgeons and patients alike.

LEVEL OF EVIDENCE

IV.

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.

Treatment of Posttraumatic Tibial Diaphyseal Bone Defects: A Systematic Review and Meta-Analysis

OBJECTIVE

To describe evidenced-based treatment options for patients who sustained trauma and/or posttraumatic osteomyelitis of the tibia resulting in diaphyseal bone defects and to compare outcomes between patients treated with nonvascularized bone grafts (NBGs), bone transport (BT), or vascularized bone grafts (VBGs).

DATA SOURCE

The Preferred Reporting Items for Systematic Review and Meta-Analyses of individual participant data and Cochrane guidelines were followed. PubMed, EMBASE, Cochrane Library, Web of Science, Scopus, and CINAHL were searched from inception to June 2020.

STUDY SELECTION

Patients who were ≥18 years, had sustained trauma to the tibia resulting in fracture and/or osteomyelitis with measurable diaphyseal bone defects, and were treated by interventions such as NBGs, BT, or VBGs were eligible. Excluded studies were non-English, reviews, nonreviewed literature, cadavers, animals, unavailable full texts, nondiaphyseal defects, atrophic nonunions, malignancy, and replantations.

DATA EXTRACTION

A total of 108 studies were included with 826 patients. Two reviewers systematically/independently screened titles/abstracts, followed by full texts to ensure quality, accuracy, and consensus among authors for inclusion/exclusion of studies. A third reviewer addressed disagreements if investigators were unable to reach a consensus. Studies were quality assessed using "Methodological Quality and Synthesis of Case Series and Case Reports".

DATA SYNTHESIS

Analyses were performed with IBM SPSS version 25.0 (IBM Corporation, Armonk, NY) and G*Power3.1.9.2.

CONCLUSIONS

NBGs may be considered first line for trauma defect sizes ≤ 10 cm or posttraumatic osteomyelitis defect sizes <5 cm. BT may be considered first line for posttraumatic osteomyelitis defect sizes <5 cm. VBGs may be considered first line for trauma and posttraumatic osteomyelitis defect sizes ≥5 cm.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Management of femoral non-union with post-traumatic bone defect using second-generation PRECICE® nail - A case report

The management of post-traumatic bone defects with non-union remains a surgical challenge. Current techniques are often fraught with complications, posing a functional, economical, and psychological challenge for the patient. A 57 year-old gentlemen suffered an open femoral fracture after a motorcycle accident. Having previously undergone open reduction internal fixation, he presented to us with atrophic non-union and bone defects, which were simultaneously treated with a second-generation PRECICE nail. Our treatment protocol was based on the strain theory, and involved initial distraction by ~5 mm at the non-union site, compression of the non-union site, followed by distraction osteogenesis at the non-union site. The patient achieved union and the initially planned limb lengthening regime was achieved with minimal complications. Self-lengthening, magnetically-driven PRECICE nails can successfully restore union and manage limb length discrepancies with reasonable patient satisfaction and minimal complications.

Bone reconstruction: Subjective evaluation and objective analysis based on conventional digital X-rays - a retrospective evaluation

BACKGROUND

Various approaches have been used to evaluate callus stiffness in distraction osteogenesis. This assessment becomes even more critical as inadequate corticalization and premature removal of the frame lead to bending, refracture, and loss of length. This study aimed to verify the objective Pixel Value Ratio (PVR) and define an evaluation scheme to assess callus tissue development during internal and external bone lengthening.

HYPOTHESIS

There are no differences between subjective parameters and objective evaluation for external and internal bone lengthening.

PATIENTS AND METHODS

We included 24 patients in this retrospective study, treated by distraction osteogenesis of the lower limb. Ten patients were treated with external ring fixators and 14 with intramedullary lengthening devices. The minimum distraction distance was 3cm. Callus tissue was evaluated with the PVR, using digital X-rays during and after treatment. We combined this method with subjective evaluation parameters, including the continuity, signal intensity, and the regeneration tissue's homogeneity, presented in the X-ray Evaluation System for Distraction Osteogenesis (XESDO).

RESULTS

The subjective evaluation showed an increase of continuity and signal-intensity between 4th postoperative weeks and complete healing with significant differences between the external and internal groups for homogeneity only after four weeks and for all parameters at 3C (p<0.05). The PVR showed an increase during consolidation with values between 0.7 and 1.0 for both groups with almost perfect interobserver agreement. Significant lower values were found in the anterior tibial cases.

CONCLUSION

PVR appears to be a practical tool for radiological evaluation of callus tissue development. In combination with the newly introduced XESDO and the surgeon's experience, these methods can be helpful for decisions during all phases of distraction osteogenesis. It is important for adapting alignment or distraction-rate, as various potential complications can be detected early. However, further studies are necessary to assess the image-based determination of callus tissue stability.

LEVEL OF EVIDENCE

III; cohort study.

Bone lengthening with magnetic nails. Experience in patients younger than 18

BACKGROUND AND GOAL

Bone elongation with magnetic endomedullary nails (MEN) has been proposed as an advantageous alternative to other techniques, by eliminating the drawbacks of external fixation. The aim of this work is to analyze the results and assess the complications in a series of patients under the age of 18.

MATERIAL AND METHODS

From 2014 to 2019, 31 elongations (23 femurs, 8 tibias) using MEN (Precice2™) have been performed in 28 patients younger than 18 (15 males and 13 females). In this observational retrospective study, only patients with follow-up longer than 18 months have been included. The average age has been 14.4 years (8-18). The most relevant aspects analyzed have been: previous shortening/deformity, elongation/correction achieved and time to full weight bearing. Complications and re-interventions have also been assessed.

RESULTS

The elongation achieved has been 5.5cm on average (3-8). In 28 elongations (90.3%) the planned goal of lengthening was achieved. The mean healing index was 1.1months/cm. More than half of elongations (55%) presented complications. Although they produced permanent sequelae in only two patients (7.1%), a total of 9 patients required re-intervention (13 operations). No infections were detected.

CONCLUSIONS

Bone lengthening with MEN in individuals younger than 18 has achieved its goal in more than 90% of patients in an effective, accurate and safe manner. The use of MEN in this series has eliminated the need for external fixators and has successfully tutorized the operated segment. The high number of complications detected in this study remains a concern.

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.

Limb salvage following snakebite using acute limb shortening and secondary lengthening

A case of 16-year-old boy from the remote tribal population of Uttarakhand is described, who sustained a viper snakebite. The patient after various interventions and referrals developed locoregional and systemic complications. He not only had an open tibiofibular fracture but a large bimalleolar defect over his lower limb. The wound infection with underlying osteomyelitis progressed to septic shock and failure of the conventional cross-leg flap. Computed tomography scan of the limb revealed a single patent vessel, eliminating the option of microvascular flap. Limb amputation was considered for source control; however, in an attempt to salvage the limb, the novel approach of acute limb shortening with secondary limb lengthening was performed with parental consent, an approach not previously reported in the management of snakebite injuries. Adequate infection control was achieved following removal of the osteomyelitic bone, and the defect was covered with overlapping tissue from the docked limb and a cross-thigh flap. Secondary lengthening was performed after 3 months, and following extensive surgical and rehabilitative interventions, the boy's limb was salvaged and he retains a near-normal gait. This case report entails a detailed account of how mutilating a snakebite injury could be and how unconventional techniques like acute limb shortening with secondary lengthening can be used in such injuries.

Systematic review of complications with externally controlled motorized intramedullary bone lengthening nails (FITBONE and PRECICE) in 983 segments

Background and purpose - In recent years motorized intramedullary lengthening nails have become increasingly popular. Complications are heterogeneously reported in small case series and therefore we made a systematic review of complications occurring in lower limb lengthening with externally controlled motorized intramedullary bone lengthening nails.Methods - We performed a systematic search in PubMed, EMBASE, and the Cochrane Library with medical subject headings: Bone Nails, Bone Lengthening, and PRECICE and FITBONE nails. Complications were graded on severity and origin.Results - The search identified 952 articles; 116 were full text screened, and 41 were included in the final analysis. 983 segments were lengthened in 782 patients (age 8-74 years). The distribution of nails was: 214 FITBONE, 747 PRECICE, 22 either FITBONE or PRECICE. Indications for lengthening were: 208 congenital shortening, 305 acquired limb shortening, 111 short stature, 158 with unidentified etiology. We identified 332 complications (34% of segments): Type I (minimal intervention) in 11% of segments; Type II (substantial change in treatment plan) in 15% of segments; Type IIIA (failure to achieve goal) in 5% of segments; and Type IIIB (new pathology or permanent sequelae) in 3% of segments. Device and bone complications were the most frequent.Interpretation - The overall risk of complications was 1 complication for every 3 segments lengthened. In 1 of every 4 segments, complications had a major impact leading to substantial change in treatment, failure to achieve lengthening goal, introduction of a new pathology, or permanent sequelae. However, as no standardized reporting method for complications exists, the true complication rates might be different.

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.

Complications of Limb Lengthening With Motorized Intramedullary Nails

Intramedullary limb lengthening (LL) is now achievable through motorized intramedullary devices. While this technology mitigates some complications of external-fixation-based lengthening, many complications common to all lengthening procedures persist. New challenges and complications exclusive to this newer technology are also presented. The LL surgeon should be aware of and ready to respond to complications involving device malfunctions, poor local bony and soft-tissue biology, patient compliance, neurovascular compromise, joint instability, regenerate problems, and others. While technology will continue to evolve, study of and adherence to foundational principles of LL will minimize risks and optimize patient outcomes.

Multi-Axis Fatigue Experimentation System of Intramedullary Implants for Femur and Tibia

Current designs of leg-lengthening implants have faced serious failures due to inadequacies in the mechanical design. The failure typically is the result of fatigue induced by a combined loading condition with axial and shear components acting in the tubular body of the implant. One of the reasons leading to the failure is improper verification testing for the design of the fatigue limit. The current test standards for pre-clinical design phases of nail implants are relatively straightforward and widely accepted yet cannot produce the three-dimensional stress state representative of the anticipated operation in a patient during the consolidation phase. This work introduces a major improvement toward a method for verifying fatigue life of tubular as well as solid implants under combined torque, axial load, and bending. The report describes a new loading fixture, a calibration method, and compares the qualification results of finite element simulation analyses and experimental measurements during cyclic loading tests. The findings state that the fixture produces controlled multi-axial loadings to study varied osteotomy locations, quasi-static strength and fatigue of intramedullary implants at an intermediate, 2 Hz, cycle rate. © 2019 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 38:984-995, 2020.

PRECICE intramedullary nail in the treatment of adult leg length discrepancy

BACKGROUND

Limb length discrepancy in adults is not an uncommon occurrence following trauma and limited literature exists on limb lengthening in skeletally mature populations using modern techniques. This study aimed to evaluate outcomes of limb lengthening surgery using the PRECICE magnetic limb lengthening intramedullary nail in an adult population.

METHOD

From 2013 to 2018, 21 adult patients were operated by a single surgeon, using the PRECICE nail, for lower limb length discrepancies. Low energy femoral osteotomies were performed via a limited approach. Tibial osteotomies were performed using a percutaneous technique and Gigli saw. A distraction rate of 0.75 mm/day was used as a standard protocol with change in rate of 0.25 mm/day implemented as required. Patients were followed up until radiological evidence of consolidation.

RESULTS

Mean patient age was 36.4 years (range 21-65), with 19 patients being male. Seventeen femoral and four tibial lengthenings were performed. Mean follow up was 15.1 months (range 6-30). Eleven patients underwent deformity correction at time of nail insertion (10 femoral, 1 tibial). All patients achieved correct lengthening (mean gain 36.5 mm, range 18-80 mm). All patients consolidated their regenerate bone (mean 268 days, range 99-825). Mean femoral consolidation index was 6.5, mean tibial consolidation index was 16.1 (p = 0.002). Six patients had delayed consolidation of regenerate bone. Increasing age (p = 0.04), number of prior operations (p = 0.03), and smoking (p = 0.01) were associated with delayed consolidation. Four of 21 (19%) patients suffered a complication, with one implant failure.

CONCLUSIONS

The PRECICE intramedullary nail is a reliable limb lengthening device in skeletally mature patients, providing predictable lengthening and bone regeneration.

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.

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.

Treatment of Post-Traumatic Femoral Discrepancy With PRECICE Magnetic-Powered Intramedullary Lengthening Nails

OBJECTIVE

To evaluate the outcomes of lengthening post-traumatic femoral segments using a recently available magnetic intramedullary (IM) lengthening system.

DESIGN

Retrospective cohort study.

SETTING

Urban level II Trauma Center.

PATIENTS/PARTICIPANTS

Patients treated for post-traumatic femoral shortening at our institution between 2012 and 2015. We identified 17 femurs lengthened (14 men and 3 women). The mean age was 30 years (range, 11-72 years).

INTERVENTION

Magnetic IM lengthening system.

MAIN OUTCOME MEASUREMENTS

Amount of lengthening achieved, consolidation index, and complications encountered.

RESULTS

The mean follow-up was 2.2 years (range, 1-3.7 years). Sixteen patients achieved the planned lengthening, a mean of 3.8 cm (range, 2.3-6.0 cm). Regenerate consolidation occurred at a mean of 119 days (range, 57-209 days). The mean consolidation index was 32 d/cm (range, 16-51 d/cm). Three patients (18%) experienced complications.

CONCLUSION

IM lengthening nails are an improvement over external fixators for treatment of post-traumatic femoral shortening. Within certain limits, their use can be extended to problems of limb-length discrepancy with angular/rotational deformity.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Lengthening and deformity correction about the knee using a magnetic internal lengthening nail

Introduction: The introduction of the internal lengthening nail (ILN) has changed the treatment of complex malalignment and shortening about the knee. Acute correction of the deformity and gradual lengthening through this osteotomy site has greatly simplified postoperative recovery. This manuscript is a review of the techniques that are currently being used in surgery.

Methods: The article is broken into two sections: distal femur osteotomy and tibia osteotomy. Each is addressed separately since they have different personalities. Also included are topics of particular interest that surface in ongoing conferences regarding the ILN. This work is a mix of expert opinion and best practice supported by peer reviewed publications on the topic.

Results: Most published series demonstrate excellent results with the ILN. Certain precautions are reiterated including avoiding mechanical failure, need for a percutaneous osteotomy, need for over-reaming, and the need for blocking screws.

Discussion: Current controversies will be brought to light and discussed. The reader should find this aspect particularly helpful in navigating this rapidly evolving field.