What's New in Limb Lengthening and Deformity Correction

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.

Limb reconstruction in a resource-limited environment

INTRODUCTION

Limb salvage and reconstruction are often challenging and even more so in the limited resource setting. The purpose of this narrative review is to explore the strategies for addressing the unique obstacles and opportunities of limb reconstructive surgery in resource-limited environments globally.

METHODS

We review (1) the global burden and dimension of the problem, (2) the relevance of orthopedic forums and communication, (3) free and open-access software for deformity analysis and correction, (4) bidirectional learning opportunities, and the value of fellowships and mentoring between resource-rich and resource-limited countries, and (5) how societies like SICOT can help to tackle the problem. Finally, case examples are presented to demonstrate the choice of surgical implants, their availability in regions with limited resources, and how the universal principles of limb reconstruction can be applied, irrespective of resource availability.

RESULTS

Limb reconstruction can often be life-changing surgery with the goals of limb salvage, improved function, and ambulation. The contradiction of relatively few severe limb deformities in high-income countries (HICs) with abundant resources and the considerable burden of limb deformities in resource-limited countries is striking. Free, open access to education and software planning tools are of paramount importance to achieve this goal of limb reconstruction. Bidirectional learning, i.e., knowledge exchange between individual surgeons and societies with limited and abundant resources, can be reached via fellowships and mentoring. The presented cases highlight (1) fixator-assisted wound closure obliviating the need for plastic surgery, (2) open bone transport, and (3) hinged Ilizarov frames for correction of severe deformities. These cases underline that optimal clinical outcome can be achieved with low-cost and readily available implants when the principles of limb reconstruction are skillfully applied.

DISCUSSION

Limb lengthening and reconstruction are based on universally applicable principles. These have to be applied regardless of the planning tool or surgical implant availability to achieve the goals of limb salvage and improved quality of life.

High-purity magnesium pin enhances bone consolidation in distraction osteogenesis via regulating Ptch protein activating Hedgehog-alternative Wnt signaling

Magnesium alloys are promising biomaterials for orthopedic implants because of their degradability, osteogenic effects, and biocompatibility. Magnesium has been proven to promote distraction osteogenesis. However, its mechanism of promoting distraction osteogenesis is not thoroughly studied. In this work, a high-purity magnesium pin developed and applied in rat femur distraction osteogenesis. Mechanical test, radiological and histological analysis suggested that high-purity magnesium pin can promote distraction osteogenesis and shorten the consolidation time. Further RNA sequencing investigation found that alternative Wnt signaling was activated. In further bioinformatics analysis, it was found that the Hedgehog pathway is the upstream signaling pathway of the alternative Wnt pathway. We found that Ptch protein is a potential target of magnesium and verified by molecular dynamics that magnesium ions can bind to Ptch protein. In conclusion, HP Mg implants have the potential to enhance bone consolidation in the DO application, and this process might be via regulating Ptch protein activating Hedgehog-alternative Wnt signaling.

Craniofacial and Long Bone Development in the Context of Distraction Osteogenesis

BACKGROUND

Bone retains regenerative potential into adulthood, and surgeons harness this plasticity during distraction osteogenesis. The underlying biology governing bone development, repair, and regeneration is divergent between the craniofacial and appendicular skeleton. Each type of bone formation is characterized by unique molecular signaling and cellular behavior. Recent discoveries have elucidated the cellular and genetic processes underlying skeletal development and regeneration, providing an opportunity to couple biological and clinical knowledge to improve patient care.

METHODS

A comprehensive literature review of basic and clinical literature regarding craniofacial and long bone development, regeneration, and distraction osteogenesis was performed.

RESULTS

The current understanding in craniofacial and long bone development and regeneration is discussed, and clinical considerations for the respective distraction osteogenesis procedures are presented.

CONCLUSIONS

Distraction osteogenesis is a powerful tool to regenerate bone and thus address a number of craniofacial and appendicular skeletal deficiencies. The molecular mechanisms underlying bone regeneration, however, remain elusive. Recent work has determined that embryologic morphogen gradients constitute important signals during regeneration. In addition, striking discoveries have illuminated the cellular processes underlying mandibular regeneration during distraction osteogenesis, showing that skeletal stem cells reactivate embryologic neural crest transcriptomic processes to carry out bone formation during regeneration. Furthermore, innovative adjuvant therapies to complement distraction osteogenesis use biological processes active in embryogenesis and regeneration. Additional research is needed to further characterize the underlying cellular mechanisms responsible for improved bone formation through adjuvant therapies and the role skeletal stem cells play during regeneration.

The Actions of IGF-1 in the Growth Plate and Its Role in Postnatal Bone Elongation

PURPOSE OF REVIEW

Bone elongation is a complex process driven by multiple intrinsic (hormones, growth factors) and extrinsic (nutrition, environment) variables. Bones grow in length by endochondral ossification in cartilaginous growth plates at ends of developing long bones. This review provides an updated overview of the important factors that influence this process.

RECENT FINDINGS

Insulin-like growth factor-1 (IGF-1) is the major hormone required for growth and a drug for treating pediatric skeletal disorders. Temperature is an underrecognized environmental variable that also impacts linear growth. This paper reviews the current state of knowledge regarding the interaction of IGF-1 and environmental factors on bone elongation. Understanding how internal and external variables regulate bone lengthening is essential for developing and improving treatments for an array of bone elongation disorders. Future studies may benefit from understanding how these unique relationships could offer realistic new approaches for increasing bone length in different growth-limiting conditions.

High-purity magnesium pin enhances bone consolidation in distraction osteogenesis model through activation of the VHL/HIF-1α/VEGF signaling

Distraction osteogenesis has widespread clinical use in the treatment of large bone defects. Nonetheless, the prolonged consolidation period carries the risk of complications. Magnesium-based materials have been shown to promote bone regeneration in fracture healing both in vitro and in vivo. Here, we investigated whether high-purity magnesium could enhance bone formation in distraction osteogenesis. High-purity magnesium pins were placed into the medullary cavity in the rat distraction osteogenesis model. Results showed that the bone volume/total tissue volume, bone mineral density, and mechanical properties of new callus were significantly higher in the high-purity magnesium group compared to stainless steel and control group (p < 0.01). Histological analyses confirmed improved bone consolidation and vascularization in high-purity magnesium group. Further, polymerase chain reaction-array investigation, Western blot, and immunohistochemical results found that vascular endothelial growth factor and hypoxia inducible factor-1α were highly expressed in the high-purity magnesium group, while Von Hippel–Lindau protein was the opposite (p < 0.01). In conclusion, high-purity magnesium implants have the potential to enhance angiogenesis and bone consolidation in the distraction osteogenesis application, and this process might be via the regulation of Von Hippel–Lindau/hypoxia inducible factor-1α/vascular endothelial growth factor signaling.

A bibliometric analysis of classic publications in web of science category of orthopedics

Background

The past century has witnessed the rapid development of operation technique, surgical instruments, and knowledge of the diseases in orthopedics. In the academic history, a number of classic papers boosted the advancement for surgery. In this paper, we performed a bibliometric analysis, aiming to determine the most influential studies within the field.

Methods

Articles were searched from the publication year of 1900 to 2016 according to the Science Citation Index Expanded database of the Clarivate Analytics Web of Science Core Collection database. Two citation indicators TC_year and C_year were employed to characterize the classic articles and the articles were identified and analyzed.

Results

A total of 30 classic articles with TC₂₀₁₆ ≥ 1000 in Web of Science category of orthopedics were identified, all written in English between 1961 and 2007 by nine countries. The minimal value of TC₂₀₁₆ was 1010; the maximum 3570; and the average 1591. Thirty classic articles were published in eight journals that were listed in the Web of Science category of orthopedics in 2016, and in two other orthopedics journals that were no longer tracked by Web of Science category of orthopedics as of 2016. Among the top 10 cited articles in both TC₂₀₁₆ and C₂₀₁₆, five articles barely received attention in the first few years after their publication, while they became cited more and more frequently in the last decade.

Conclusion

This study evaluated the development and trend of orthopedics research by adopting bibliometric analysis. It serves as a guide for investigators in the future research.

Enhancement of bone regeneration with the accordion technique via HIF-1α/VEGF activation in a rat distraction osteogenesis model

Axial micromotion of bone fragments promotes callus formation and bone healing during the process of distraction osteogenesis (DO). This study investigated the effects of the combined axial compression and distraction (accordion) technique on bone regeneration in rat DO model. Male Sprague-Dawley rats (n = 62) underwent right tibial transverse osteotomy and were randomly divided into four groups after lengthening: control (no manipulation) and three experimental groups assigned on the basis of the period of accordion manoeuvres in the consolidation phase (Groups 1, 2, and 3 with accordion technique applied at Weeks 1, 3, and 5, respectively). Animals were terminated at 1 week after each accordion phase (i.e., Weeks 2, 4, and 6). Callus formation was monitored by X-ray radiography; new bone quality was evaluated by microcomputed tomography, histological analysis, and mechanical testing. Serum levels of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) were measured. Callus formation after accordion manoeuvre at Week 3 (Group 2) increased significantly over time of consolidation. The microcomputed tomography and mechanical analysis revealed Group 2 had more newly formed bone and superior mechanical properties in contrast to the other groups at termination. Histomorphological and immunohistochemical analyses confirmed a greater degree of osteogenesis and angiogenesis corresponding to increased serum levels of HIF-1α and VEGF in Group 2. The accordion technique was effective in promoting bone consolidation via activation of HIF-1α/VEGF during DO. The accordion technique may be used in the middle phase of bone consolidation to promote bone formation in patients undergoing DO treatment.

[Application of Orthofix unilateral external fixator in the treatment of musculoskeletal tumors]

Objective

To investigate the surgical characteristics and preliminary effectiveness of Orthofix unilateral external fixator in the treatment of musculoskeletal tumors.

Methods

Twenty-two patients received Orthofix unilateral external fixator treatment for bone defect after tumor excision or complications after limb salvage surgery between June 2011 and March 2016. There were 11 males and 11 females with a median age of 23.5 years (range, 4-57 years). The bone defect or limb length discrepancy after tumor resection was at proximal femur in 6 cases, distal femur in 8 cases, diaphysis of femur in 3 cases, proximal tibia in 2 cases, and diaphysis of tibia in 3 cases. The external fixation was used for temporary fixation after reconstruction of bone defect in 10 cases [the length of bone defect was 6-19 cm (mean, 12.3 cm); using vascularized fibular graft in 2 cases, allograft bone and free fibular graft in 2 cases, allograft bone and autogenous bone graft in 5 cases, allograft bone reconstruction in 1 case]; bone distraction lengthening for limb length discrepancy in 5 cases [the length of shortening was 6.5-8.5 cm (mean, 7.5 cm)]; temporary fixation after open biopsy in 3 cases; bone transportation over locking plate in 1 case (the length of bone defect was 7.5 cm); fixation for preoperatively pathology fracture in 1 case; and joint distraction for dislocation after tumor ablation in 2 cases.

Results

All the patients were followed up 12-72 months (mean, 36 months). In 10 patients with bone defect reconstruction, the wearing external fixator time was 3-8 months (mean, 4.8 months); all got bone union with the healing time of 3-16 months (mean, 6.4 months); the Musculoskeletal Tumor Society 93 (MSTS 93) score was 73.3-93.3 (mean, 87.2); and no complication occurred during wearing external fixator. In 5 patients with bone distraction lengthening for limb length discrepancy, the wearing external fixator time was 7-15 months; 2 patients had axial deviation during distraction and2 had greenstick fracture after apparatus removal; pin site infection was observed in 2 cases with grade 1 and 1 case with grade 2 according to Checketts-Otterburn classification system; the MSTS 93 score was 80.0-96.7 (mean, 89.2). The remaining patients had no complications, the knee and ankle joint movement was normal.

Conclusion

Orthofix unilateral external fixator can be used in fixation for complex bone defect after tumor resection and to correct limb length discrepancy after limb salvage surgery.

Humeral lengthening and deformity correction

INTRODUCTION

Ilizarov principles and hybrid fixation have improved the results of humeral lengthening. We reviewed the literature on humeral lengthening using different fixators with regard to indications, operative technique, results and complications. We also retrospectively reviewed 56 segments in 46 patients treated with humeral lengthening and deformity correction using Ilizarov external fixation. The etiology was achondroplasia (10 patients), epiphyseal injury (8 cases), infection (11 cases) and Erb's palsy (17 cases). The average age at surgery was 14 years (range 8-20 years). The patients were assessed clinically and radiographically and DASH score was available for 36 segments. Follow-up ranged from 1-11 years. The magnitude of lengthening achieved ranged from 5-15.5 cm with an average of 9 cm. The average healing index was 29.5 cm (range 26-37 days). The percentage of area of lengthening to the original length ranged from 25 to 100% with an average of 55%. The average DASH (available for 36 segments only) score ranged from 15-40 preoperatively to 7-16 (P = 0.04) at last follow-up. Functionally, all the patients returned to their preoperative jobs and daily activities including sports.

COMPLICATIONS

Complications included pin track infection in 46 segments, radial nerve palsy which recovered completely in 2 patients, fracture of the regenerate in 7 cases and premature consolidation of the regenerate in one case.

CONCLUSION

Humeral lengthening, whether unilateral or bilateral, is a valid method that improves the outcome following arm shortening and deformity correction, including angulation and rotation. Extensive lengthening up to 100% of the original length could be achieved without increasing the risk of complications.

LEVEL OF EVIDENCE

IV, retrospective cohort.

SIMPLIFIED CALCULATION FOR CORRECTIVE OSTEOTOMIES OF LONG BONES

Objectives:

To present a simplified calculation for the measurement of osteotomy wedges used for the correction of angular uniplanar deformities of long bones and to compare the simplified calculation proposed (circumferential calculation) with the classical trigonometric calculations, as well as with the exact calculation performed by computer software AutoCADtm.

Methods:

The software AutoCADtm was used to calculate the bone wedges, for mathematical comparison of the three main groups, each one of them containing 18 hypothetical bone deformities which angles ranging from 5 to 90 degrees, with 5 degrees intervals between them.

Results:

In the analysis of 18 deformities, the hypothetical angular bone, the average lengths of the corrective wedges obtained by the trigonometric, circumferential and the exact metods were, respectively, 32.21 ± 16.81 mm, 33.16 ± 18.63 mm and 35.22 ± 23.52 mm. There was no statistically significant difference between the three calculation methods (p>0.05).

Conclusion:

The circumferential calculation proposed in this study is useful for being accurate and simple, not requiring any trigonometric knowledge. Level of Evidence II, Experimental Study.