Metatarsal lengthening by distraction osteogenesis for brachymetatarsia in paediatric patients: is it safe and effective?

PURPOSE: The primary aim is to assess the efficacy of the surgical callus distraction technique of the metatarsus in paediatric patients. Secondary objectives are to assess complications and treatment duration. We have also described the details of our surgical technique. MATERIALS AND METHODS: A case series review of paediatric patients who had metatarsal lengthening at our unit between 2014 and 2022. Patient demographics, duration of time in frame, complications and metatarsal length achieved were recorded. The AOFAS Midfoot and the MOXFQ were taken pre-operatively and at final follow-up. RESULTS: Sixteen metatarsals in 8 patients (14 feet) underwent lengthening between 2014 and 2022 using the MiniRail OrthoFix 100 (Orthofix Medical Inc, Lewisville, TX, USA). The mean age was 13.3 (12-17) years. The average duration between surgery and implant removal was 5.2 months. According to Paley's classification, there was one obstacle encountered in a patient who required a revision of their osteotomy and one problem in another patient who had an infected metatarsophalangeal joint stabilising k-wire treated with oral antibiotics. The Mean AOFAS Midfoot score improved from 53.10 to 86.40 (p < 0.0001) and the Mean MOXFQ improved from 32.5000 to 12.1250 (p < 0.05); these were statistically significant. CONCLUSION: Gradual metatarsal lengthening using the MiniRail external fixator is a safe and effective method to treat brachymetatarsia in paediatric patients. This preliminary report describes and supports metatarsal lengthening in appropriate patients. Holistic care in terms of a pre-operative assessment, psychological support and preparation for the extended rehabilitation period are vital.

[Options and limits of leg length correction in paediatric orthopaedics]. / Möglichkeiten und Grenzen der Beinlängenkorrektur in der Kinderorthopädie.

For paediatric orthopaedic surgeons treating leg length discrepancy, knowledge of the available procedures and their options and limits is just as important as mastery of the very different surgical methods and implants, as well as the possible complications, in order to be able to advise and treat the children and adolescents and their parents comprehensively and in the best interests. Both the growth inhibiting procedures and the complex bone lengthening procedures require a great deal of experience to successfully guide patients and families through what is often a lengthy and sometimes complicated treatment process. Careful preoperative indications and planning, precise surgical techniques with suitable instruments and implants, and attentive postoperative check-ups are mandatory prerequisites for the desired therapeutic success.

Outcomes of Limb Lengthening With Computer-assisted Hexapod External Fixators in the Treatment of Fibular Hemimelia.

BACKGROUND: Fibular hemimelia (FH) represents the most common deficiency of the long bones and is associated with multiple deformities. Reconstructive treatment with external fixators in FH restores normal lower extremity alignment and length with plantigrade feet for a balanced and effective gait. The aim of this study is to evaluate the outcomes of lower limb lengthening and simultaneous tri-plane deformity correction with a computer-assisted hexagonal external fixator in children with FH. METHODS: A retrospective review was performed for FH cases treated with a computer-assisted hexagonal external fixator in a tertiary referral center. Leg length discrepancy (LLD), interphyseal angles, tibiocalcaneal distances, healing index (HI), and callus shapes were analyzed for radiologic evaluation, and the Pediatric Quality of Life Inventory (PedsQL) was used for functional assessment. Limbs with HI <50 days/cm, PedsQL >75, and without regenerate fractures were considered successful lengthenings. RESULTS: Twenty-four limbs of 23 patients were included. The limbs were lengthened for a mean of 7.24 cm (range, 4.7 to 15.6). The initial LLD of 5.6 cm (range, 0.5 to 19 cm) increased to 1.7 cm (range, 0.1 to 6 cm), and the mean interphyseal angle was 12.7 degree (range, 1.5 to 54.2 degree), tibiocalcaneal distance was 0.85 cm (range, 0.1 to 1.7) at final follow-up. The most common regenerated bone morphology was cylindrical, as seen in 11 limbs (45.8%). The average PedsQL score was 83.5 (range, 69.5 to 96.7). Sixteen limbs (66.7%) had successful lengthening at their first, and 4 limbs (80%) had successful lengthening at their second surgeries. Seven limbs had complications requiring surgical intervention (29.1%), with 3 (12.5%) regenerate fractures after external fixators removal. CONCLUSIONS: Limb reconstruction with computer-assisted hexapod fixators is a successful and reliable option for the treatment of LLD in FH, and patients demonstrate good functional outcomes. Surgeons should be aware of potential complications and should utilize prophylactic measures when necessary. LEVELS OF EVIDENCE: Level III, retrospective comparative study.

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

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

[Paramedical care related to the implantation of a motorized spinal lengthening nail]. / Soins paramédicaux liés à l'implantation d'un clou d'allongement médullaire motorisé.

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.

Feasibility of Computer-Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates.

OBJECTIVE: To evaluate the feasibility and utility of computer-aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators. METHODS: In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction-consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T-test. RESULTS: The mean limb lengthening achieved was 6.41 ± 2.54 (range, 3.30-10.54) cm with either varus or valgus correction. The mean operative duration was 151 ± 41.87 (84-217) minutes and mean blood loss was 53.58 ± 22.51(25-87) ml. The mean distraction-consolidation time was 3.67 ± 1.13 (range, 2.5-6.0) months and mean external fixator duration was 11 ± 2.45 (range, 8-14) months. The mean healing index (HI) was 18.11 ± 3.58 (range, 12.8-22.7) days/cm. Mean LEFS scores improved postoperatively from 32.17 ± 8.57 (range, 24-45) to 61.17 ± 6.68 (range, 50-67) with a significant difference (T = -14.26,P < 0.001). CONCLUSIONS: Simultaneous length and angular correction can be achieved by incorporating CAD into the surgical treatment of patients with LLD, without compromising postoperative lower limb function. CAD demonstrates utility in the surgical treatment of LLD by improving the functionality of monorail external fixators.

Bifocal femoral lengthening assisted by preoperative 3-dimensional design in the restoration of posttraumatic limb length discrepancy.

BACKGROUND: To assess the clinical outcomes of preoperative three-dimensional planning followed by bifocal femoral lengthening in the treatment of posttraumatic limb length discrepancy (LLD). METHODS: A total of 8 eligible patients with posttraumatic femoral LLD > 6 cm were admitted to our institution from January 2015 to January 2018 and treated by bifocal femoral lengthening with the assistance of 3-dimensional imaging technology. The following data were collected: detailed demographic information, the amount of lengthening, external fixation time (EFT), external fixation index (EFI), postoperative bone and functional outcomes, and complications in the follow-up period. RESULTS: All included patients were successfully followed up for in an average of 55.4 ± 6.7 months after removal of the external fixator. There were six males and two females with an average age of 38.4 ± 12.2 years. The mean preoperative LLD was 69.2 ± 6.2 mm. The mean lengthening amount was 67.5 ± 6.9 mm. The mean EFT was 180.1 ± 20.2 days. The EFI was 26.73 ± 1.36 days/cm on average. All patients achieved satisfactory postoperative bone and functional outcomes. No major complications such as nerve or vascular injury were observed. CONCLUSIONS: Bifocal femoral lengthening with preoperative three-dimensional design provided precise surgical guidance and resulted in satisfactory postoperative outcomes, demonstrating that it is an effective treatment for posttraumatic femoral LLD.

Quality of life of children during distraction osteogenesis: a comparison between intramedullary magnetic lengthening nails and external fixators.

BACKGROUND: Distraction osteogenesis is a very demanding process. For decades, external fixation was the only reliable option for gradual deformity correction. Recently, intramedullary magnetic nails have gained popularity. This research aimed to assess the quality of life in children during gradual deformity correction using intramedullary lengthening nails compared to external fixation. METHOD: Prospective analysis included children who had gradual lower limb deformity correction between 2017 and 2019. Group A included children who had magnetic lengthening nails; patients in group B had external fixation devices. Child health utility 9D (CHU- 9D) and EuroQol 5D youth (EQ- 5D-Y) were used to measure the quality of life at fixed points during the distraction osteogenesis process. The results were used to calculate the utility at each milestone and the overall quality of life adjusted years (QALYs). RESULTS: Thirty-four children were recruited, group A had 16 patients, whilst group B had 18 patients. The average ages were 16.0 years and 14.7 years for groups A and B, respectively. Group A patients reported significantly better utility compared to group B. This was observed during all stages of treatment (P = 0.00016). QALYs were better for group A (0.44) compared to group B (0.34) (P < 0.0001). CONCLUSION: The quality of life was generally better in group A compared to group B. In most patients, the health utility progressively improved throughout treatment. In the same way, QALYs were better with the lengthening nails compared to external fixators. The magnetic lengthening devices (PRECICE nails) which were used in this research were recently relabelled to restrict their applications in children; this study was conducted before these restrictions.

What Are the Potential Benefits and Risks of Using Magnetically Driven Antegrade Intramedullary Lengthening Nails for Femoral Lengthening to Treat Leg Length Discrepancy?

BACKGROUND: Limb lengthening with magnetically driven intramedullary lengthening nails is a fast-developing field and represents an alternative to external fixators. Although previous studies have assessed the application of magnetically driven intramedullary lengthening nails, these studies have been heterogenous regarding the nailing approach, the bone treated, and the implant type; they also have analyzed relatively small patient groups at short follow-up durations. QUESTIONS/PURPOSES: (1) Is femoral lengthening with magnetically driven antegrade intramedullary lengthening nails accurate and precise? (2) What are the most common complications of treatment? (3) What factors are associated with unplanned additional surgery? METHODS: We retrospectively analyzed the longitudinally maintained database of our orthopaedic teaching hospital to identify all patients who underwent surgery for leg length discrepancy (LLD) between October 2014 and April 2019. In total, we surgically treated 323 patients for LLD of 2 cm or more. Of those 55% (177 of 323) were treated with distraction osteogenesis with magnetically driven intramedullary lengthening nails, 18% (59 of 323) with external fixation, and 27% (87 of 323) with epiphysiodesis around the knee. Based on that, 29% (93 of 323) of patients underwent unilateral femoral distraction osteogenesis with magnetically driven antegrade femoral lengthening nails and were eligible for analysis. No patient was excluded, and 3% (3 of 93) were lost before the minimum study follow-up of 2 years, leaving 97% (90 of 93) for analysis. Patients with a distal femoral deformity were treated via a retrograde femoral approach (10% [33 of 323]) or with external fixators (3% [10 of 323]) and were not included in this study. Distraction osteogenesis with magnetically driven intramedullary lengthening nails was not considered for patients with deep tissue infection, those with bone dimensions considered to be too small in relation to the available implants, and for patients younger than 8 years. This study included 90 patients (44 females, 43 left femora) treated for a median (interquartile range) preoperative LLD of 39 mm (32 to 52) at a median age of 15 years (14 to 17). The same limb lengthening system was applied in all patients. The median (IQR) follow-up was 35 months (24 to 78). Data were acquired through a chart review performed by someone not involved in the surgical care of the included patients. Data acquisition was supervised and curated by two of the involved surgeons. Accuracy was calculated as 100 - [(achieved distraction in mm - planned distraction in mm) / (planned distraction in mm) x 100] and precision as 100 - (relative standard deviation of accuracy). Treatment-associated complications were summarized descriptively and characterized as complications resulting in unplanned additional surgery or those not resulting in unplanned surgery. To analyze the risk of unplanned additional surgery by entity, we calculated odds ratios (ORs) comparing the incidence of unplanned additional surgery in the different entity cohorts with the idiopathic LLD cohort as a reference. By calculating ORs, we analyzed the risk for unplanned additional surgery depending on sex, age, surgery time, and previous lengthening. Due to the lack of long-term evidence about motorized lengthening nails remaining in situ and concerns about potential implant-related adverse effects, removal was routinely scheduled 1 year after consolidation. For implant removal, 92% (83 of 90) of patients underwent planned additional surgery, which was not recorded as an adverse event of the treatment. Ninety-seven percent (87 of 90) of patients completed lengthening with the implant remaining in situ until the end of distraction. The median (IQR) distraction length was 37 mm (30 to 45) with a median distraction index of 0.9 mm/day (0.7 to 1.0) and median consolidation index of 31 days/cm (25 to 42). RESULTS: The calculated accuracy and precision were 94% and 90%, respectively. In total, 76% (68 of 90) of our patients experienced complications, which resulted in 20% (18 of 90) of patients undergoing unplanned additional surgery. The most common complication overall was adjustment of the distraction rate in 27% (24 of 90) of patients (faster: 16% [14 of 90]; slower: 11% [10 of 90]) and temporary restriction of knee motion, which occurred in 20% (18 of 90) of our patients and resolved in all patients who experienced it. The most serious complications were bacterial osteomyelitis and knee subluxation, which occurred in 3% (3 of 90) and 1% (1 of 90) of our patients, respectively. With the numbers available, we found only one factor associated with an increased likelihood of unplanned additional surgery: Patients with postinfectious LLD had higher odds of unplanned additional surgery than patients with idiopathic LLD (7% [1 of 15] versus 50% [3 of 6], OR 14.0 [95% CI 1.06 to 185.49]; p = 0.02). However, we caution readers this finding is fragile, and the confidence interval suggests that the effect size estimate is likely to be imprecise. CONCLUSION: Femoral distraction osteogenesis with magnetically driven antegrade intramedullary lengthening nails appears to be an accurate and reliable treatment for femoral lengthening. However, depending on the etiology, a high risk of unplanned additional surgery should be anticipated, and a high proportion of patients will experience temporary joint stiffness. We recommend close orthopaedic follow-up and physiotherapy during treatment. This treatment of LLD can be considered alongside other nails, external fixators, and epiphysiodesis. Multicenter studies comparing this with other approaches are needed. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Implant failure after externally magnetic-controlled nail lengthening.

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

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.

Has the Threshold for Epiphysiodesis Versus Lengthening Changed in the Era of Magnetically Controlled Nails?

INTRODUCTION: Limb length discrepancy (LLD) is common in both the pediatric and adult population. Length inequalities can be due to a multitude of etiologies including congenital, developmental, and acquired causes. There has been little consensus on the morbidity of LLD and, as a result, the threshold necessary for treatment of LLD to prevent morbidity. Advances in magnetically controlled lengthening devices achieve greater accuracy and patient satisfaction and create an opportunity to lower the threshold for limb lengthening. DISCUSSION: Asymptomatic LLD is relatively common in both pediatric and adult populations. Only ~10% of the population has equal leg length. LLD of <5 cm may lead to long-term morbidities such as scoliosis, lower back pain, gait abnormalities, stress on hip or knee joint, and lower extremity symptomatic versus asymptomatic osteoarthritis. The teaching in most orthopaedic textbooks is to adjust the shoe if symptomatic for discrepancies up to 2 cm; consider an orthotic, epiphysiodesis, or skeletal shortening for 2.5 to 5 cm; and possible limb reconstruction for >5 cm. The assumption is that there are no long-term consequences of mild LLD. However, data in recent literature show that small discrepancies may contribute to pathologic changes such as pain, gait abnormalities, and osteoarthritis. Major advances have been made in limb lengthening over the past 40 years. The increased accuracy and superior patient satisfaction of the magnetically controlled lengthening nail versus external fixation methods argue for including lengthening for LLD of <5 cm. CONCLUSION: If mild LLD can cause long-term pathology, it is important to counsel families on the full range of options for limb equalization no matter the size of the discrepancy. The evolution in technology and understanding of limb lengthening has provided additional safe surgical options. Therefore, the historic treatment protocol for addressing limb differences may need to include lengthening for smaller discrepancies even <2 cm.

Impairment and restoration of the blood-nerve barrier and its correlation with pain following gradual nerve elongation of the rat sciatic nerve.

Purpose: This study aimed to evaluate the time course of impairment and restoration of the blood-nerve barrier (BNB) following gradual elongation of the sciatic nerve and to clarify its association with nociception.Materials and Methods: The right femur was lengthened at a rate of 1.5 mm/day for 10 days. Von Frey tests were performed until 50 days after lengthening. Compound muscle action potentials (CMAPs) were measured to assess gross dysfunction of the elongated nerve. Evans blue-albumin tracing and immunohistochemistry for endothelial barrier antigen (EBA), rat endothelial cell antigen-1 (RECA-1), and CD68 for qualitative and quantitative analysis of the BNB and macrophage infiltration were performed for up to 50 days after cessation of lengthening in three segments of the sciatic nerves.Results: Paw-withdrawal threshold was significantly decreased at 7 days from initiation and began to recover from day 25 after lengthening. CMAPs showed delayed latency and attenuated amplitude but recovered at day 30 after cessation. On days 10 and 30 after cessation, spotted leakage of Evans blue-albumin in the endoneurium was observed, and the ratio of EBA/RECA-1-positive microvessels was significantly decreased, which subsequently recovered simultaneously in all segments on day 50 after cessation. Macrophages did not infiltrate the BNB at any time point.Conclusion: The restoration of BNB function following gradual nerve elongation was associated with the resolution of mechanical allodynia. Our findings provide insight into the association between nerve stretch injury and chronic nociception in adult male rats, which are potentially relevant to human orthopedic procedures and chronic neuropathic pain.

Older age and multi-joint external fixator are two risk factors of complications in ulnar lengthening in children with hereditary multiple exostosis.

OBJECTIVES: Hereditary multiple exostosis (HME) often involves forearm deformities. The aim of this study was to present the clinical results of 37 children who underwent ulnar lengthening with two different types of unilateral external fixators and to investigate the risk factors of complications. METHODS: We evaluated 37 children with forearm deformities caused by HME treated in our hospital from January 2008 to July 2019. The surgical procedures included resection of exostosis, osteotomy of the ulna, and gradual lengthening of the ulna with a unilateral external fixator. According to the type of fixator they received, the children were divided into two groups: group A received monorail fixators and group B received multi-joint fixators. Radiographic and functional parameters were assessed. Complications were recorded. RESULTS: All patients were followed-up for an average of 4.6 years (3.0 to 6.5). In both group A and group B, the ulna shortening (US), radial articular angle (RAA), carpal slip (CS), elbow flexion, forearm pronation, supination, and Mayo Elbow Performance Score (MEPS) values improved significantly from preoperatively to postoperatively (p < 0.05). However, the ulnar deviation was observed in 4 cases in group B and no cases in group A. According to logistic regression, the difference was only related to age (p < 0.05) and the type of external fixator (p < 0.05). CONCLUSIONS: Ulnar lengthening with unilateral external fixation is a safe and effective procedure for the treatment of HME. Regarding complications, deviation of the ulna axis was more likely to occur in older children with multi-joint external fixators.

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.

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.

Bone transport versus acute shortening for the management of infected tibial bone defects: a meta-analysis.

BACKGROUND: The treatment for infected tibial bone defects can be a great challenge for the orthopaedic surgeon. This meta-analysis was conducted to compare the safety and efficacy between bone transport (BT) and the acute shortening technique (AST) in the treatment of infected tibial bone defects. METHODS: A literature survey was conducted by searching the PubMed, Web of Science, Cochrane Library, and Embase databases together with the China National Knowledge Infrastructure (CNKI) and the Wanfang database for articles published up to 9 August 2019. The modified Newcastle-Ottawa scale (NOS) was adapted to evaluate the bias and risks in each eligible study. The data of the external fixation index (EFI), bone grafting, bone and functional results, complications, bone union time and characteristics of participants were extracted. RevMan v.5.3 was used to perform relevant statistical analyses. Standard mean difference (SMD) was used for continuous variables and relative risk (RR) for the binary variables. All of the variables included its 95% confidence interval (CI). RESULTS: Five studies, including a total of 199 patients, were included in the study. Statistical significance was observed in the EFI (SMD = 0.63, 95% CI: 0.25, 1.01, P = 0.001) and bone grafting (RR = 0.26, 95%CI: 0.15, 0.46, P < 0.00001); however, no significance was observed in bone union time (SMD = - 0.02, 95% CI: - 0.39, 0.35, P = 0.92), bone results (RR = 0.97, 95% CI: 0.91, 1.04, P = 0.41), functional results (RR = 0.96, 95% CI: 0.86, 1.08, P = 0.50) and complications (RR = 0.76, 95% CI: 0.41, 1.39, P = 0.37). CONCLUSIONS: AST is preferred from the aspect of minimising the treatment period, whereas BT is superior to AST for reducing bone grafting. Due to the limited number of trials, the meaning of this conclusion should be taken with caution for infected tibial bone defects.

Clinical results and complication rates of lower limb lengthening in paediatric patients using the PRECICE 2 intramedullary magnetic nail: a multicentre study.

Implantable intramedullary nail lengthening devices (e.g., PRECICE 2 system) have been proposed as alternative method to external fixation for lower limb lengthening surgery. The aim of this study was to analyse our outcomes and complications using the PRECICE 2 (P2) nail system and review them in light of the existing literature. A retrospective multicentre study was conducted on patients <18 years, who were treated for limb lengthening using the P2 system. The inclusion criteria were a limb length discrepancy ≥ 30 mm and a follow-up ≥6 months after the end of treatment. A total of 26 (15 males) patients were included, average age was 14.7 ± 2.3 years; 26 nails (21 femur, 5 tibia) were implanted. The average goal lengthening was 49.4 ± 12.4 mm, while average achieved lengthening was 44.4 ± 11.6 mm. Average distraction and consolidation indexes were 11.9 ± 2.1 days/cm and 25.1 ± 8.1 days/cm, respectively. Nail accuracy and reliability were 91.1% and 88.5%, respectively. A total of five problems (joint contractures), one obstacle (femur fracture) and three complications (hip joint subluxation, deep infection and nail running back) were encountered. The P2 nail system is a valid alternative to external fixator for limb lengthening in young patients with no significant angular or rotation deformities. Our study confirms a favourable complication rate and available evidence from literature suggests a lower complication rate than external fixator systems. Nevertheless, surgeons should keep a watchful eye on risk of joint subluxation and mechanical complications with intramedullary lengthening.

The Crooked Rod Sign: A New Radiological Sign to Detect Deformed Threads in the Distraction Mechanism of Magnetically Controlled Growing Rods and a Mode of Distraction Failure.

STUDY DESIGN: Case report. OBJECTIVE: To report a unique mechanical failure of magnetically controlled growing rods (MCGRs) that is related to continuous rod slippage. SUMMARY OF BACKGROUND DATA: Despite the growing popularity of MCGR in the management of patients with early onset scoliosis, postoperative complications and reoperations are not uncommon. Unique complications or unplanned reoperations are observed in patients with MCGRs that are not seen in traditional growing rods. The complications include rod slippage, mismatch between targeted and achieved distraction length, metallosis, and actuator pin fracture. We have identified an unreported failure mechanism whereby deformed threads occur in the internal distraction mechanism of the MCGR. This phenomenon may indicate increased MCGR internal screw friction and increased distraction resistance. Increased friction and resistance ultimately led to distraction failure and revision surgery. METHODS: A girl with early onset scoliosis (EOS) was treated by dual MCGRs. She developed proximal junctional kyphosis (PJK) and continuous rod slippage. Distractions in the out-patient clinic and under sedation did not achieve successful rod lengthening. A tell-tale "crooked rod" radiological sign was identified by angulation between the actuator and the extendable portion of the rod. RESULTS: Rod exchange was performed and she is now 2 years after revision surgery with successful lengthening episodes. Upon review of the extracted MCGR, distraction was not possible even after rod removal and was only resumed after the screw was manually reinserted along its correct threads. CONCLUSION: Deformed threads is a complication that cannot be reverted without rod removal and exchange. Users should be aware of this potential failure mechanism and proceed to early rod exchange rather than attempting any further distractions. LEVEL OF EVIDENCE: 4.