Bone lengthening using the Fitbone(®) motorized intramedullary nail: The first experience in France

Mechanical Axis Deviation Shift in Limb Lengthening Over the Anatomical Axis, a Retrospective Analysis

Background

Recently, limb lengthening devices have shifted from external fixators to telescoping magnetic intramedullary lengthening nails (MILNs), which lengthen strictly along the bone's anatomic axis. Baumgart proposed the reverse planning method, overcorrecting lateral shift with a distal osteotomy and slight varus angulation. The untested assumption that antegrade lengthening along the anatomic axis causes lateral mechanical axis deviation (MAD) prompted our study, which examines MILNs' effect on lower limb alignment.

Methods

We retrospectively evaluated records for 154 femoral antegrade MILNs inserted in 122 adult patients for limb lengthening. We excluded patients who underwent concomitant corrective osteotomies or tibial lengthening, or who had malunion, nonunion, mechanical failure, or revision surgery for any reason. Long-leg standing radiographs were taken preoperatively, at the end of lengthening, around 3 months postoperatively, and at the culmination of consolidation (approximately 6 months postoperatively). MAD and anatomic mechanical angle (AMA) were assessed as primary outcomes at each radiographic time point for sequential comparison. The predicted MAD was derived from the trigonometric formula (Predicted MAD = lengthening × sin [AMA]).

Results

Average preoperative MAD was 2.4 mm medial (SD = 10.6), diminishing to 1.9 mm medial (SD = 13.2) by the end of lengthening. On assessment at consolidation, average MAD had equilibrated back to 2.6 mm medial. Our results showed a net shift of 0.18 mm, whereas the predicted shift was 5.4 mm. The mean preoperative AMA was 5.9 mm (SD = 1.49). At the end of lengthening, the average AMA had decreased to 4.8 mm (SD = 1.4).

Conclusion

Our data indicated minimal to no impact on the mechanical axis or joint alignment of the lower limb after antegrade lengthening using a telescoping femoral MILN in a deformity-free femur. Study results suggested that the femur typically realigned in a way that minimized mechanical deviation while preserving joint alignment.

Level of Evidence

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

Bone Regeneration After Nail Distraction Osteogenesis: Review of Current Knowledge and Application Combined with a Case Report with Radiological, Histological, and Electron Microscopic Analysis

Background: Limb-lengthening surgeries via nail distraction osteogenesis (DO) have become more popular lately. This provides an opportunity to study human bone that has grown longer. Case details: We present a case of a 22-year-old male who underwent internal upper and lower leg lengthening by 12 cm and 6 cm, respectively, under full weight bearing. He requested bilateral femoral shortening by 4 cm using a shortening nail, 24 months after the index surgery. The regenerated bones were harvested and analyzed. Results: Good bone quality and well-organized structure were observed in the regenerated bones compared with the native human adult bony architecture. Conclusions: This case demonstrates that bilateral bone regeneration during DO with a nail can result in a bone morphology that is comparable to that of native adult human bony macro- and micro-anatomy. This supports the effectiveness and potential of this surgical approach for limb lengthening and shortening procedures, although more investigations are necessary in this regard.

Comparative Efficacy and Safety of Intramedullary Lengthening Nails vs. Alternative Techniques for Femoral Limb Lengthening: A Systematic Review and Meta-Analysis

BACKGROUND

Limb lengthening procedures are performed for various indications, including limb length discrepancies (LLDs) and short stature. This systematic review and meta-analysis compares the efficacy and safety of the newer motorized intramedullary lengthening nails (MILNs) with the traditional alternative techniques (ATs) for femoral limb lengthening.

METHODS

We conducted a comprehensive literature search in the Medline, Embase, Cochrane, Web of Science, and Scopus databases, inclusive of all dates through July 1, 2023, and without language restrictions. Factors mediating outcomes included problems, obstacles, complications, total adverse events, healing/consolidation index, time to full weight-bearing, lengthening accuracy, percentage of lengthening goal achieved, and duration of hospital stay. Effect sizes were quantified using STATA 17.0. Statistical algorithms employed were random effects model standardized mean differences (SMDs) for continuous outcomes and log risk ratios (RRs) for dichotomous outcomes, both with 95% confidence intervals (CIs).

RESULTS

Our meta-analysis included 10 studies comparing MILN with AT: 180 femurs in the MILN group and 160 femurs in the AT group. This was exclusively comprised of retrospective cohort studies. When compared with AT, limb lengthening procedures utilizing MILNs had significantly lower problems (log RR, -1.35; 95% CI, -1.93 to -0.77; p < 0.001), complications (log RR, -0.56; 95% CI, -0.90 to -0.22; p = 0.001), and total adverse events (log RR, -0.69; 95% CI, -1.17 to -0.21; p = 0.005), as well as a superior bone healing index (SMD, -0.80; 95% CI, -1.32 to -0.28; p = 0.003). However, no significant differences were found in obstacles, percentage of lengthening goal achieved, lengthening accuracy, time to full weight-bearing, and duration of hospital stay.

CONCLUSION

Limb lengthening with MILNs vs. AT may offer more favorable patient outcomes, lowering risk for problems, complications, and total adverse events, while optimizing the bone healing/consolidation index. However, the limitation of nonrandomized retrospective studies and high heterogeneity should be acknowledged.

LEVEL OF EVIDENCE

Level II (meta-analysis of cohort studies). See Instructions for Authors for a complete description of levels of evidence.

Clinical compatibility of magnetic resonance imaging with magnetic intramedullary nails: a feasibility study

INTRODUCTION

The use of magnetic resonance imaging (MRI) with a magnetic intramedullary lengthening nail in place is contraindicated per the manufacturer due to the concern of implant activation and migration. A prior in vitro study did not confirm these complications only noting that a 3.0 T MRI weakened the internal magnet. Therefore, a retrospective analysis of patients who underwent an MRI with a magnetic nail in place was performed to determine if any adverse effects occurred in the clinical setting.

MATERIALS AND METHODS

A retrospective review of all patients who underwent an MRI with a magnetic lengthening nail in place was performed. The time spent being imaged in the MRI, number of times the patient entered the MRI suite, and the images obtained were recorded. Radiographs were performed before and after the MRI to determine if any hardware complications occurred. The patients were monitored for any adverse symptoms while they were in the suite.

RESULTS

A total of 12 patients with 13 nails were identified. Two patients underwent imaging with a 3.0 T MRI while the remaining 10 underwent imaging with a 1.5 T MRI. Each patient entered the MRI suite 2.1 times and spent an average of 84.7 min being imaged in the MRI (range 21-494). No patients noted any adverse symptoms related to the nail while in the suite and no hardware complications were identified.

CONCLUSION

MRI appears to be safe with a magnetic nail in place and did not result in any complications. Given the manufacturer's recommendations, informed consent should be obtained prior to an MRI being performed and a 3.0 T MRI should be avoided when possible if further activation of the nail is required.

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.

[Paramedical care related to the implantation of a motorized spinal lengthening nail]

The Fitbone® system is one of the most recent motorized bone lengthening techniques. It allows a precise control of the extension while reducing pain and complications. It requires special assistance from the paramedical team, before and after the procedure, as it may cause adjustment problems in some patients.

Maximizing length with precice nail: a novel technique

Intramedullary magnetic lengthening nails represents a marked advance in the process of limb lengthening, reducing the complications associated with other methods, and improving patient's comfort. However, one important limitation is its lengthening ability, especially when it comes to short bones. Previous reports have shown techniques that may allow further lengthening but at a cost of having to carry out repeated procedures, requiring the use of other devices, and submitting the patient to long-winded surgical procedures. This report presents a novel technique to achieve lengthening beyond the initial reach of the nail, in a simple and quick procedure, without the need of implanting any additional devices.

Removal of broken PRECICE Stryde intramedullary lengthening nails

This paper describes two different techniques for removal of broken Precice Stryde intramedullary bone lengthening nails, which unlike trauma nails are solid containing mechanical components. Consequently, surgeons face unique challenges when these implants brake within medullary canal. Here, we present our surgical approach for removal of three broken implants. In one patient (46kg) both Ø10mm femoral Stryde implants (max. weight allowance 68kg) broke through the proximal locking screw hole preoperatively on the right side and intraoperatively on the left side (413 and 504 days after index surgery respectively). The third Ø11.5 femoral nail broke through the area containing the magnet (55kg patient, 325 days after index surgery). LEVEL OF EVIDENCE: IV.

Radiographs of 366 removed limb-lengthening nails reveal differences in bone abnormalities between different nail types

AIMS

Limb-lengthening nails have largely replaced external fixation in limb-lengthening and reconstructive surgery. However, the adverse events and high prevalence of radiological changes recently noted with the STRYDE lengthening nail have raised concerns about the use of internal lengthening nails. The aim of this study was to compare the prevalence of radiological bone abnormalities between STRYDE, PRECICE, and FITBONE nails prior to nail removal.

METHODS

This was a retrospective case series from three centres. Patients were included if they had either of the three limb-lengthening nails (STYDE, PRECICE, or FITBONE) removed. Standard orthogonal radiographs immediately prior to nail removal were examined for bone abnormalities at the junction of the telescoping nail parts.

RESULTS

In total, 306 patients (168 male, 138 female) had 366 limb-lengthening nails removed. The mean time from nail insertion to radiological evaluation was 434 days (36 to 3,015). Overall, 77% of STRYDE nails (20/26) had bone abnormalities at the interface compared with only 2% of FITBONE (4/242) and 1% of PRECICE nails (1/98; p < 0.001). Focal osteolysis in conjunction with periosteal reaction at the telescoping interface was only observed in STRYDE nails.

CONCLUSION

Bone abnormalities at the interface of telescoping nail parts were seen in the majority of STRYDE nails, but only very rarely with FITBONE or PRECICE nails. We conclude that the low prevalence of radiological changes at the junctional interface of 242 FITBONE and 98 PRECICE nails at the time of nail removal does not warrant clinical concerns. Cite this article: Bone Joint J 2021;103-B(11):1731-1735.

Pain, osteolysis, and periosteal reaction are associated with the STRYDE limb lengthening nail: a nationwide cross-sectional study

Background and purpose - Observing serious adverse events during treatment with the Precice Stryde bone lengthening nail (NuVasive, San Diego, CA, USA), we conducted a nationwide cross-sectional study to report the prevalence of adverse events from all 30 bone segments in 27 patients treated in Denmark.Patients and methods - Radiographs of all bone segments were evaluated regarding radiographic changes in February 2021. We determined the number of bone segments with late onset of pain and/or radiographically confirmed osteolysis, periosteal reaction, or cortical hypertrophy in the junctional area of the nail.Results - In 30 bone segments of 27 patients we observed radiographic changes in 21/30 segments of 20/27 patients, i.e., 19/30 osteolysis, 12/30 periosteal reaction (most often multi-layered), and 12/30 cortical hypertrophy in the area of the junction between the telescoping nail parts. Late onset of pain was a prominent feature in 8 patients. This is likely to be a prodrome to the bony changes. Discoloration (potential corrosion) at the nail interface was observed in multiple removed nails. 15/30 nails were still at risk of developing complications, i.e., were not yet removed.Interpretation - All Stryde nails should be monitored at regular intervals until removal. Onset of pain at late stages of limb lengthening, i.e., consolidation of the regenerate, should warrant immediate radiographic examination regarding osteolysis, periosteal reaction, and cortical hypertrophy, which may be associated with discoloration (potential corrosion) of the nail. We recommend removal of Stryde implants as early as possible after consolidation of the regenerate.

Bone Lengthening with a Motorized Intramedullary Nail in 34 Patients with Posttraumatic Limb Length Discrepancies

The Fitbone® motorized nail system has been used to correct limb length discrepancies (LLD) for several years. This study focuses on its application in posttraumatic limb lengthening surgery, its outcome and challenges.

MATERIALS AND METHODS

A prospective, single center study was conducted between 2010 and 2019 in patients treated with motorized lengthening nails. The inclusion criteria were symptomatic LLD of 20 mm or more. An imaging analysis was done using TraumaCad® software (Brainlab AG, Munich, Germany) to compare frontal alignment angles and limb length discrepancy (LLD) on preoperative and latest follow-up radiographs of the lower limbs.

RESULTS

Thirty-four patients were included with a mean age of 28.8 ± 9.7 years, a mean follow-up of 27.8 ± 13 months and a mean hospital stay of 4.4 ± 1.7 days. The mean LLD was 44 ± 18 mm in 29 femoral and 32 ± 8 mm in 4 tibial cases, which was reduced to less than 10 mm in 25/34 (74%) patients. The mean healing index was 84.6 ± 62.5 days/cm for femurs and 92 ± 38.6 days/cm for tibias. The mean time to resume full weight-bearing without walking aids was 226 days ± 133. There was no significant difference between preoperative and final follow-up alignment angles and range of motion. The mechanical lateral distal femoral angle (mLDFA) was corrected in the subgroup of 10 LLD patients with varus deformity of the femur (preoperative 95.7° (±5.0) vs. postoperative 91.5° (±3.4), p = 0.008). According to Paley's classification, there were 14 problems, 10 obstacles and 2 complications.

DISCUSSION

Six instances of locking screw pull out, often requiring reoperation, raise the question of whether a more systematic use of blocking screws that provide greater stability might be indicated. Lack of compliance can lead to poor outcomes, patient selection in posttraumatic LLD patients is therefore important.

CONCLUSION

Limb lengthening with a motorized lengthening nail for posttraumatic LLD is a relatively safe and reliable procedure. Full patient compliance is crucial. In-depth knowledge of lengthening and deformity correction techniques is essential to prevent and manage complications.

[Research progress of intramedullary lengthening nail technology]

Objective

To review the research progress of intramedullary lengthening nail technology.

Methods

The foreign literature on the development history, types, advantages and disadvantages, indications and contraindications, complications, and effectiveness of intramedullary lengthening nail were reviewed and analyzed.

Results

The intramedullary lengthening nail system mainly includes mechanical type, electric motor drive type, and magnetic drive type. Compared with traditional external fixation and lengthening technology, the intramedullary lengthening nail technology has certain advantages in incidence of complications, bone healing, postoperative functional rehabilitation, incision aesthetics, convenience, and patient satisfaction. However, there are also shortcomings, such as pain, uncontrollable distraction rate, device failure, etc. In the clinical application of intramedullary lengthening nails for limb lengthening, the indications should be grasped reasonably, and the related complications should be prevented and treated.

Conclusion

Intramedullary lengthening nails provide a new option for limb lengthening, and the initial effectiveness is good. It is one of the development direction of limb lengthening technology.

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.

Medium-term evaluation of leg lengthening by ISKD® intramedullary nail in 28 patients: Should we still use this lengthening system?

INTRODUCTION

Lower-limb lengthening presently uses intramedullary nailing. There are motorized systems and mechanical systems, each with their specific complications. The aim of the present study was to assess the efficacy of ISKD® mechanical nails (Orthofix Inc., Texas, USA) on 3D EOS® imaging, and also complications and functional impact.

HYPOTHESIS

The study hypothesis was that nail lengthening is effective but should no longer use the ISKD® system, due to the high rate of specific complications.

MATERIAL AND METHODS

A single-center retrospective study included 28 patients (14 female, 14 male) undergoing limb-lengthening by ISKD® nail between 2005 and 2018. Mean age was 29 years. Twenty-four procedures were femoral and 4 tibial. Lengthening and consolidation parameters and residual discrepancy were measured on 3D EOS® imaging. Complications and functional scores were collated.

RESULTS

Twenty-eight ISKD® nails were implanted in 28 patients. Mean follow-up was 75 months. Planned lengthening was achieved in 78.5% of cases, for a mean lengthening of 34.5mm. Mean lengthening and consolidation indices were respectively 0.94mm/day and 105 days/cm. Length discrepancy showed significant correction, with improvement in functional scores (p<0.01). The overall complications rate was 67.9%, 76% of which were specific to the ISKD® nail.

DISCUSSION

The present study confirmed that nail lengthening is an indication of choice in lower-limb length discrepancy, but that the ISKD® system should no longer be used, due to an excessive rate of specific complications. Complications are due to deficient control of lengthening rate, not found with new-generation motorized nails, which show much fewer complications.

LEVEL OF EVIDENCE

IV, retrospective study without control group.

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.

Exploring the Ethics of Stature Lengthening as Treatment for Height Dysphoria

AIM

To promote a discussion on the ethics and justifications of stature lengthening in patients without skeletal deformity.

BACKGROUND

Stature lengthening for height gain in patients without skeletal deformity has stirred controversy within the orthopedic community. However, current literature does not delineate the ethical issues surrounding this procedure. Improvements in the techniques, technology, and safety profile of stature lengthening warrant an ethical discussion to challenge, justify, and guide the use of this surgical procedure.

REVIEW RESULTS

Examination of ethical issues leads to the distinction between the dual roles of stature lengthening as a treatment vs an enhancement. The primary focus on stature lengthening as treatment allows for exploration of "height dysphoria"-a psychological burden caused by a dissatisfaction with one's height-as the primary pathology that may justify surgical intervention.

CONCLUSION

In our opinion, additional work is required to establish "height dysphoria" as a true pathology in order to ethically justify stature lengthening as a legitimate form of treatment. Further discussion is needed to address the ethics of stature lengthening as an enhancement.

CLINICAL SIGNIFICANCE

This paper addresses salient ethical issues of stature lengthening in patients without skeletal deformity by exploring historical, contemporary, and comparative contexts.

HOW TO CITE THIS ARTICLE

Lee RC, Aulisio M, Liu RW. Exploring the Ethics of Stature Lengthening as Treatment for Height Dysphoria. Strategies Trauma Limb Reconstr 2020;15(3):163-168.

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.

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.

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.

Bone reconstruction after malignant tumour resection using a motorized lengthening intramedullary nail in adolescents: preliminary results

PURPOSE

Bone reconstruction after malignant tumour of the lower limbs is a challenge. Our aim was to investigate the results of bone lengthening and transport using the Fitbone motorized lengthening nail.

METHODS

Eight patients were included. Two patients had had a tumour involving soft tissue only without bone resection. In six patients, the initial bone defect was 15.5 cm (8 to 24). The first step of reconstruction had consisted of temporary fixation and a cement spacer. The second step had consisted of bone grafting in five patients. One patient was managed with bone transport. Eventually, five patients had a limb-length discrepancy (LLD) managed with bone lengthening only. Two patients had a LLD and a nonunion managed with bone transport and lengthening. Mean age at bone lengthening was 15.2 years (11 to 19). Mean follow-up was 30.5 months (10 to 48).

RESULTS

In all, 11 nails were implanted in eight patients (eight femurs, three tibias). Mean length gain per procedure was 54.5 mm (30 to 80). Mean healing index was 48.4 days per cm (22.6 to 85.7). The complication rate was 18%. In two cases we observed a loose locking screw, which was revised. In all cases the lengthening involved the short bone (femur or tibia). Mean Musculoskeletal Tumor Society (MSTS) score improved from 52.7 (16.6 to 73.3) to 79.9 (63.3 to 96.6).

CONCLUSIONS

Bone reconstruction using a motorized intramedullary nail stands as a safe and reliable alternative after malignant tumour. It allows biological reconstruction with satisfactory clinical and radiological outcome and low complication rate.

LEVEL OF EVIDENCE

III.

Blocking Screw-assisted Intramedullary Nailing Using the Reverse-rule-of-thumbs for Limb Lengthening and Deformity Correction

Introduction

Historically, blocking screws have been used to assist in acute reduction of fractures during intramedullary (IM) nailing. The reverse-rule-of-thumbs (RROT) for blocking screws was introduced to facilitate internal lengthening nail use in deformity correction and limb lengthening. Our study investigated the ability of blocking screws, using same principle, to accurately correct long-bone deformity with and without lengthening and to prevent lengthening-induced deformity.

Materials and methods

This is an institutional review board (IRB)-approved retrospective study on 86 patients who had IM nail-assisted limb reconstruction of femur or tibia with blocking screws. Surgeries were performed for deformity correction, limb lengthening, or deformity correction and limb lengthening. Data on the following variables were collected: number of blocking screws, distance of each blocking screw to osteotomy, distance of osteotomy from joint line, and amount of lengthening. Mechanical axis deviation (MAD) and joint alignment parameters were measured preoperatively and at the final postoperative follow-up. The primary outcome was the ability to obtain desired MAD and joint orientation angles. Accuracies were reported as postoperative measurements relative to goal. Association for the Study and Applications of the Methods of Ilizarov (ASAMI) scores were collected.

Results

The accuracy of deformity correction was within 6 mm from goal, while joint orientation was corrected to within 1.5° of goal. Number of blocking screws did not significantly impact accuracy. Distance of blocking screw to osteotomy and amount of lengthening did not affect accuracy. In femurs, osteotomies greater than 10 cm from the joint line were more accurate in MAD goal (p = 0.017). This result was not replicated in tibias. ASAMI scores were excellent or good.

Conclusion

Using RROT configuration, blocking screws were effective in correcting deformities of lower extremity long bones and in preventing deformity during limb lengthening. If positioned correctly, number of screws and their distance to osteotomy did not affect accuracy. Amount of lengthening did not impact accuracy. Distal femoral osteotomy less than 10 cm from knee joint may be challenging even with using blocking screws.

How to cite this article

Dabash S, Zhang DT, Rozbruch SR, et al. Blocking Screw-assisted Intramedullary Nailing Using the Reverse-rule-of-thumbs for Limb Lengthening and Deformity Correction. Strategies Trauma Limb Reconstr 2019;14(2):77–84.

Salvage of congenital pseudarthrosis of the tibia by the induced membrane technique followed by a motorised lengthening nail

An 18-year-old male with neurofibromatosis type I was treated for congenital pseudarthrosis of the tibia using the Masquelet induced-membrane technique with internal fixation by retrograde implantation of a transplantar intramedullary nail. Bone healing was obtained at the expense of malunion with external rotation and 5.5cm of lower limb shortening. A motorised intramedullary-lengthening nail (Fitbone^®, Wittenstein, Igersheim, Germany) was implanted. This treatment was successful in correcting the rotational malalignment and limb length discrepancy. The motorised nail Fitbone^® may be a valid option for treating complex cases of limb length discrepancy, including those combined with limb deformities.

Humeral Lengthening with the PRECICE Magnetic Lengthening Nail

BACKGROUND

Different types of external fixators have been used for humeral lengthening with successful outcomes reported in literature. Motorized intramedullary (IM) lengthening nails have been developed as an alternative to external fixators for long bone lengthening in the lower extremity.

QUESTIONS/PURPOSES

This case series reports on using the new technology of IM lengthening nails for humeral lengthening. We assessed the radiological healing and functional outcomes after using the PRECICE IM nail for humeral lengthening.

METHODS

This multicenter retrospective study included a total of six humeri in five patients (mean age was 20 years) that underwent lengthening with the magnetic IM PRECICE nail in two centers in the USA. The etiology was humeral growth arrest post-bone cyst (two segments), post-septic growth arrest (two segments), and multiple hereditary exostosis (bilateral segments in one patient). The outcomes measured were the length achieved, distraction index (DI; the length achieved in mm divided by the duration of lengthening in days), consolidation index (CI; number of days from surgery until consolidation divided by the length of the regenerate in cm), complications encountered, and functional outcomes (shoulder and elbow range of motion, the upper extremity functional index (UEFI), and QuickDASH functional scores).

RESULTS

The mean follow-up period was 1.8 years (0.9 to 2.4 years). All segments achieved the goal of lengthening; the mean was 5.1 cm (4.5 to 5.8 cm). Mean DI was 0.7 mm/day (0.5 to 0.8). Mean CI was 36 days/cm (25 to 45 days/cm). No complications were observed. At the last follow-up, all patients maintained their preoperative range of motion (ROM) except one patient had reduced shoulder ROM. QuickDASH score and upper extremity functional index showed postoperative improvement compared to the preoperative scores.

CONCLUSION

IM lengthening nails can provide successful and safe humeral lengthening. Specifically, the PRECICE nail has accurate control over the lengthening process.

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.

Use of internal lengthening nails in post-traumatic sequelae

External fixators are a well-established modality for treating fractures with bone defects, leg-length discrepancy, malunion, nonunion and other post-traumatic consequences. However, use of internal lengthening rods has remarkably increased recently for post-traumatic conditions. The main advantage of internal lengthening rods is eliminating pin-site complications. Internal lengthening rods are also associated with less pain. Motorised internal lengthening rods show promising performance in post-traumatic cases. Rigorous pre-operative planning is paramount to reducing lengthening-related complications. Certain types of internal lengthening rods offer bidirectional movement capability. Nail mechanism malfunction is a possibility with all kinds of nails. Direct doctor supervision is required, especially in the initial stages while the nail is lengthening. Internal lengthening nails are not as stiff as regular nails, with intricate internal mechanisms that can be broken under inattentive weightbearing activities. Preliminary positive outcomes indicate the role of internal lengthening rods in treating post-traumatic problems of leg-length discrepancy, malunion and nonunion.

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.

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.

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.