Pure vascularized periosteal transplants have been shown to be extremely effective at achieving rapid bone healing in children with biologically complex non-union. Free tibial and fibular periosteal transplants are generally indicated when large periosteal flaps are necessary. We report using a vascularized femoral myo-periosteal graft (VFMPG) to treat distal tibial osteotomy non-union in a six-year-old boy with congenital pseudarthrosis of the tibia. The graft consisted of a 9 cm myo-periosteal flap (after 50% of elastic retraction) that incorporated the vastus intermedius muscle and diaphyseal femoral periosteum nourished by the descending branch of the lateral circumflex femoral vessels. Plantaris medialis was used as a recipient vessel. Healing occurred 10 weeks after surgery. The patient resumed gait and sports activity without orthosis. No donor or recipient site complications occurred 17 months after surgery. Employing a VFMPG might be an alternative to other free or large vascularized periosteal flaps currently in use for complex pediatric non-unions.

Forearm non-union poses a challenge in orthopaedic surgery due to its intricate anatomy and functional significance. This review provides a comprehensive overview of the assessment, diagnosis and management of forearm non-union. Initial evaluation involves a meticulous history, physical examination and imaging studies to identify factors contributing to non-union, including infection. Surgical approaches are discussed, with emphasis on restoring biomechanical stability and promoting bone healing. Treatment options range from autografts to allografts, with considerations for vascularised bone transfers in complex cases. Decision-making strategies are outlined, considering patient-specific factors and individualised treatment plans. Special considerations for specific types of forearm non-unions are addressed, along with postoperative care protocols to optimise healing and functional outcomes. Overall, this review aims to provide clinicians with a comprehensive understanding of forearm non-union management based on current evidence and clinical practice. Level of Evidence: Level V (Therapeutic).

Background: The surgical treatment of bony non-unions is traditionally performed with additional bone grafts when atrophic and/or stronger implants when hypertrophic. In the case of the clavicle shaft, however, in our experience, a more controversial method where no additional bone graft is needed leads to equally good consolidation rates, independent of the non-union morphology. This method requires the meticulous anatomical reconstruction of the initial fracture and fixation according to the AO principle of relative stability. Methods: A retrospective review following the STROBE guidelines was performed on a consecutive cohort of all patients who received surgical treatment of a midshaft clavicle non-union at the Medical Center of the University of Freiburg between January 2003 and December 2023. Patients were identified using a retrospective systematical query in the Hospital Information System (HIS) using the International Statistical Classification of Diseases and Related Health Problems Version 10 (ICD-10) codes of the German Diagnosis Related Groups (G-DRG). Two groups were formed to compare the consolidation rates of patients who received additional bone grafting from the iliac crest with those of patients who did not. A 3.5 mm reconstruction LCP plate was used in all patients. Consolidation rates were evaluated using follow-up radiographs and outcomes after material removal with a mean follow-up of 31.5 ± 44.3 months (range 0-196). Results: Final data included 50 patients, predominantly male (29:21); age: 46.0 ± 13.0 years, BMI 26.1 ± 3.7. Autologous bone grafts from the iliac crest were used in 38.0% (n = 19), while no bone addition was used in 62.0% (n = 30). Six patients were lost to follow-up. Radiological consolidation was documented after a mean of 15.1 ± 8.0 months for the remaining 44 patients. Consolidation rates were 94.4% (n = 17) in patients for whom additional bone grafting was used and 96.2% (n = 25) in patients for whom no graft was used. There was no relevant difference in the percentage of atrophic or hypertrophic non-unions between both groups (p = 0.2425). Differences between groups in the rate of consolidation were not significant (p = 0.7890). The complication rate was low, with 4.5% (n = 2). Conclusions: Independent of the non-union morphology, non-unions of the clavicle midshaft can be treated successfully with 3.5 mm locking reconstruction plates without the use of additional bone grafting in most cases.

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) has not shown superior benefit overall in cost-effectiveness during adult spinal deformity (ASD) surgery.
METHODS: Retrospective PURPOSE: Generate a risk score for pseudarthrosis to inform the utilization of rhBMP-2, balancing costs against quality of life and complications.
METHODS: ASD patients with 3-year data were included. Quality of life gained was calculated from ODI to SF-6D and translated to quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions for complications and comorbidities. Established weights were generated for predictive variables via logistic regression to yield a predictive risk score for pseudarthrosis that accounted for frailty, diabetes, depression, ASA grade, thoracolumbar kyphosis and three-column osteotomy use. Risk score categories, established via conditional inference tree (CIT)-derived thresholds were tested for cost-utility of rhBMP-2 usage, controlling for age, prior fusion, and baseline deformity and disability.
RESULTS: 64% of ASD patients received rhBMP-2 (308/481). There were 17 (3.5%) patients that developed pseudarthrosis. rhBMP-2 use overall did not lower pseudarthrosis rates (OR: 0.5, [0.2-1.3]). Pseudarthrosis rates for each risk category were: No Risk (NoR) 0%; Low-Risk (LowR) 1.6%; Moderate Risk (ModR) 9.3%; High-Risk (HighR) 24.3%. Patients receiving rhBMP-2 had similar QALYs overall to those that did not (0.163 vs. 0.171, p = .65). rhBMP-2 usage had worse cost-utility in the LowR cohort (p < .001). In ModR patients, rhBMP-2 usage had equivocal cost-utility ($53,398 vs. $61,581, p = .232). In the HighR cohort, the cost-utility was reduced via rhBMP-2 usage ($98,328 vs. $211,091, p < .001).
CONCLUSIONS: Our study shows rhBMP-2 demonstrates effective cost-utility for individuals at high risk for developing pseudarthrosis. The generated score can aid spine surgeons in the assessment of risk and enhance justification for the strategic use of rhBMP-2 in the appropriate clinical contexts.
METHODS: III.

The reconstruction of long bone defects as a result of primary traumatic, secondary infection or tumor-related loss of substance continues to represent a surgical challenge. Callus distraction via segment transport, vascularized bone transfer and the induced membrane technique (IMT) are established methods of reconstruction. In recent decades IMT has experienced increasing popularity due to its practicability, reproducibility and reliability. At the same time, the original technique has undergone numerous modifications. The results are correspondingly heterogeneous. This overview is intended to explain the basic principles of IMT and to provide an overview of the various modifications and their complications.
UNASSIGNED: Die Rekonstruktion langstreckiger Knochendefekte infolge von primär traumatischen oder sekundär infektions- oder tumorbedingten Substanzverlusten stellt nach wie vor eine chirurgische Herausforderung dar. Die Kallusdistraktion über Segmenttransport, der vaskularisierte Knochentransfer und die induzierte Membrantechnik (IMT) stellen etablierte Verfahren der Rekonstruktion dar. In den letzten Jahrzehnten erfreut sich die IMT aufgrund ihrer Praktikabilität, Reproduzierbarkeit und Zuverlässigkeit zunehmender Popularität. Gleichsam erfuhr die Originaltechnik eine Vielzahl von Modifikationen. Die Ergebnisse stellen sich als entsprechend heterogen dar. Diese Übersicht soll die wesentlichen Grundprinzipien der IMT darlegen und einen Überblick über die verschiedenen Modifikationen und ihre Komplikationen geben.

BACKGROUND: Pedicle subtraction osteotomy (PSO) is effective for correcting spinal malalignment but is associated with high complication rates. The biomechanical effect of different PSO levels remains unclear, and no finite element (FE) analysis has compared L2-, L3-, L4-, and L5-PSOs.
OBJECTIVE: To assess the effects of PSO level on the spine\'s global range of motion, stresses on posterior instrumentation, load sharing with the anterior column, and proximal junctional stresses.
METHODS: A computational biomechanical analysis.
METHODS: A validated 3D spinopelvic FE model (T10-Pelvis) was used to perform PSOs at L2, L3, L4 and L5. Each model was instrumented with a four-rod configuration (primary rods + in-line satellite rods) from T11-Pelvis. Simulation included a 2-step analysis; (1) applying 300 N to thoracic, 400 N to lumbar, and 400 N to sacrum, and (2) applying a 7.5 Nm moment to the top endplate of the T10 vertebral body. Acetabulum surfaces were fixed in all degrees of freedom. The range of motion, spinopelvic parameters (lumbar lordosis (LL), sacral slope (SS), pelvic incidence (PI), and pelvic tilt (PT)), PSO force, and von Mises stresses were measured. All models were compared with the L3-PSO model and percentage differences were captured.
RESULTS: Compared to the intact alignment: LL increased by 48%, 45%, 59%, and 56% in the L2-, L3-, L4-, and L5-PSO models; SS increased by 25%, 15%, and 11% while PT decreased by 76%, 53%, and 45% in L2-, L3-, and L4-PSOs (SS and PT approximated intact model in L5-PSO); Lumbar osteotomy did not affect the PI. Compared to L3-PSO: L2-, L4-, and L5-PSOs showed up to 32%, 34%, and 34% lower global ROM. The least T10-T11 ROM was observed in L5-PSO. The left and right SIJ ROM were approximately similar in each model. Amongst all, the L5-PSO model showed the least ROM at the SIJ. Compared to L3-PSO, the L2-, L4-, and L5-PSO models showed up to 67%, 61%, and 78% reduced stresses at the UIV, respectively. Minimum stress at UIV+ was observed in the L3-PSO model. The L2-and L3-PSOs showed the maximum PSO force. The L5-PSO model showed the lowest stresses on the primary rods in all motions.
CONCLUSIONS: Our FE investigation indicates that L5-PSO results in the greatest lumbar lordosis and lowest global, SIJ, and T10-T11 ROMs and stresses on the primary rods, suggesting potential mechanical benefits in reducing the risk of rod breakage. However, L4- and L5-PSOs led to the least force across the osteotomy site, which may increase the risk of pseudarthrosis. These findings provide biomechanical insights that may inform surgical planning, though further clinical investigation is essential to determine the optimal PSO level and validate these results.
CONCLUSIONS: Understanding the biomechanical impact of PSO level is crucial for optimizing surgical outcomes and minimizing the risks of post-operative complications.

OBJECTIVE: To report the rate of fusion in a sample of patients undergoing lumbar fusion surgery and assess interrater reliability of computed tomography (CT)-based parameters for the assessment of fusion.
METHODS: All adult patients who underwent lumbar fusion surgery from 2017 to 2021 were retrospectively identified. Patient demographics and surgical characteristics were collected through chart review of the electronic medical records. CT scans were reviewed independently by two attending spine surgeons and two spine fellows. Fusion was defined as evidence of bone bridging in any one of (1) posterolateral gutters, (2) facets, or (3) interbody (when applicable) on any CT views. Evidence of screw haloing was indicative of nonunion. Interrater reliability was determined using cohen\'s kappa. Afterwards, a consensus agreement for each component of fusion was reached between participants.
RESULTS: The overall fusion rate among all procedures was 63/69 (91.3%). Overall 22/25 (88.0%) TLIF, 16/19 (84.2%) PLDF, 3/3 (100%) LLIF, and 22/22 (100%) circumferential fusions experienced a successful fusion. Interrater reliability was good for interbody fusion (k = 0.734) and moderate for all other measures (k = 0.561 for posterolateral fusion; k = 0.471 for facet fusion; k = 0.458 for screw haloing). Overall, interrater reliability as to whether a patient had a fusion or nonunion was moderate (k = 0.510).
CONCLUSIONS: There was only moderate interrater reliability across most radiographic measures used in assessing lumbar fusion status. Reliability was highest when evaluating the presence of interbody fusion. The majority of fusions occurred across the facet joints.

Objective: To investigate the clinical and radiologic characteristics of children with congenital pseudarthrosis of the tibia (CPT) in a single center. Methods: This is a retrospective case series study. According to inclusion and exclusion criteria, clinical data of 497 children(507 limbs) with CPT who were treated at Department of Orthopedics, the Children\'s Hospital Affiliated to Xiangya School of Medicine, Central South University from January 2011 to December 2020 were collected. Baseline data included gender, age at initial visit, age at onset of symptoms, accompanying symptoms, domicile, whether first treated at our hospital, and treatment-related information such as surgical or conservative treatment, surgical complications, etc., were extracted and analyzed using the health information system. Imaging data of the children, including Crawford classification, bilateral leg lengths, presence of fibular pseudarthrosis, and location of pseudarthrosis along the tibia segment, were analyzed using the Picture Archiving and Communication System. Data were compared using independent sample t test or χ2 tests. Results: Among 497 children with CPT, there were 305 males (61.4%) and 192 females (38.6%). The age at initial visit was (3.6±3.2) years (range: 0.1 to 16.2 years). Neurofibromatosis type 1 (NF1) symptoms were positive in 340 children (68.4%), and negative in 157 children (31.6%). Among NF1-positive children, those with symptoms onset before 1 year of age were significantly more than NF1-negative children (74.1%(252/340) vs. 66.2%(104/157);χ2=9.24, P=0.001), and the proportion of fractures (92.9%,316/340) was significantly higher than that in the NF1-negative group (84.7%,133/157) (χ2=8.33, P=0.004). According to imaging data, Crawford type Ⅳ was the most common type, with 321 limbs (63.3%), followed by type Ⅱ in 100 limbs (19.7%), type Ⅲ in 54 limbs (10.7%) and type Ⅰ in 32 limbs (6.3%). Pseudarthrosis occurred in the proximal third of the tibia in 14 limbs (2.8%), in the middle third in 185 limbs (36.5%), and in the distal third in 308 limbs (60.8%). Seventy-four children (14.9 %) had associated fibular pseudarthrosis. The lateral proximal tibial angle was 86.91°±5.21°(range: 72.17° to 102.08°), and the lateral distal tibial angle was 87.27°±10.73°(range: 51.07° to 128.17°). A total of 421 children (84.7%) underwent surgical treatment with (3.1±2.4) surgeries performed per child (range:0 to 12 surgeries); 76 children (15.3%) received conservative treatment. Postoperative complications mainly included ankle valgus (77 cases), leg length discrepancy (71 cases),refracture (48 cases), osteomyelitis (11 cases), and hardware failure (10 cases). NF1-positive children underwent more surgeries than NF1-negative children ((5.1±2.2)times vs.(2.1±1.8)times;t=14.93,P<0.01). Conclusions: Crawford type Ⅳ is the most common type of CPT in children in this study. CPT predominantly occurs in the middle or distal third of the tibia. The majority of children with CPT experienced symptoms and were seen at outpatient clinics before the age of 3 years. The main surgical complications currently associated with CPT treatment are ankle valgus and leg length discrepancy. Compared with CPT without NF1, children with NF1-positive CPT tend to have earlier symptom onset and may require more frequent treatments.
目的： 探讨单中心先天性胫骨假关节（CPT）患儿的临床和影像学特征。 方法： 本研究为回顾性病例系列研究。根据纳入标准和排除标准，收集2011年1月至2020年12月于中南大学湘雅医学院附属儿童医院就诊的497例（507条患肢）CPT患儿的临床资料。利用健康信息系统提取并分析患儿的基线资料，包括性别、首诊年龄、首次出现症状年龄、合并症、户籍地等；以及治疗相关资料，包括手术或保守治疗情况、手术相关并发症等。通过影像存档与传输系统提取并分析患儿影像学资料，包括Crawford分型、双下肢长度差异、是否伴有腓骨假关节以及假关节对应的胫骨的节段。数据比较采用独立样本t检验或χ2检验。 结果： 497例CPT患儿中，男305例（61.4%），女192例（38.6%），首次入院年龄（3.6±3.2）岁（范围：0.1~16.2岁）。合并神经纤维瘤病1型（NF1）患儿340例（68.4%），非NF1患儿157例（31.6%）。在合并NF1的患儿中，首发症状出现在1岁以内［74.1%（252/340）比66.2%（104/157），χ2=9.24，P=0.001］和发生骨折的比例［92.9%（316/340）比84.7%（133/157），χ2=8.33，P=0.004］明显高于不合并NF1患儿。影像学资料显示，507条患肢中Crawford Ⅳ型最多，共321例次（63.3%），其次为Crawford Ⅱ型100例次（19.7%）、Crawford Ⅲ型54例次（10.7%）和Crawford Ⅰ型32例次（6.3%）。CPT发生于胫骨近端1/3处14例次（2.8%），中段1/3处185例次（36.5%），远端1/3处308例次（60.8%）。合并腓骨假关节的患儿74例（14.9%）。胫骨近端外侧角为86.91°±5.21°（范围：72.17°~102.08°），胫骨远端外侧角为87.27°±10.73°（范围：51.07°~128.17°）。421例（84.7%）患儿接受了手术治疗，在我科手术次数为（3.1±2.4）次（范围：0~12次）；76例（15.3%）患儿接受了保守治疗。手术并发症包括踝关节外翻77例、双下肢不等长71例、再骨折48例、骨髓炎11例、内固定物断裂10例。合并NF1患儿的手术次数多于不合并NF1患儿［（5.1±2.2）次比（2.1±1.8）次；t=14.93，P<0.01］。 结论： 本组CPT患儿中Crawford Ⅳ型比例最高，且多见于胫骨中段或远端1/3。多数患儿的首次出现症状年龄在3岁以内。CPT手术治疗后的主要并发症为踝关节外翻和双下肢不等长；合并NF1的CPT患儿的首发症状更早且可能需要接受更多次手术治疗。.

OBJECTIVE: Nonunion and significant subsidence after anterior cervical discectomy and fusion (ACDF) are associated with poor clinical outcomes, which occasionally lead to revision surgery. Allograft and polyetheretherketone (PEEK) cages are the two most commonly used interbody spacer devices for ACDF. Although studies have been conducted to compare the efficacies of these two interbody materials, the question remains regarding the superiority of one over the other. Therefore, the authors conducted a systematic review and meta-analysis to compare nonunion, subsidence, and reoperation rates after ACDF using allograft and PEEK cages as interbody devices.
METHODS: In this systematic review and meta-analysis, the authors systematically searched the MEDLINE, EMBASE, and Cochrane Library databases for studies published prior to November 2023 that compared the efficacy and safety of allograft and PEEK cages for ACDF. A pooled analysis was designed to identify differences in nonunion, subsidence, and reoperation rates between the two interbody devices.
RESULTS: Ten studies involving 1462 patients (allograft, 852 patients; PEEK cage, 610 patients) were included. The pooled analysis demonstrated that allograft had a significantly lower rate of nonunion compared to that of PEEK cages (OR 0.33, 95% CI 0.14-0.79; p = 0.01). Furthermore, the reoperation rate due to nonunion was significantly higher with PEEK cages compared to that with allograft (OR 0.28, 95% CI 0.11-0.71; p < 0.01), whereas the reoperation rate due to overall causes did not display significant results (OR 0.38, 95% CI 0.11-1.29; p = 0.12). The incidence of significant subsidence (OR 0.66, 95% CI 0.28-1.55; p = 0.34) and the mean amount of subsidence (standard mean difference 0.03, 95% CI -0.42 to 0.47; p = 0.90) did not demonstrate significant differences between allograft and PEEK cages.
CONCLUSIONS: Overall, the current meta-analysis suggests the advantages of allograft over PEEK cages used for ACDF, due to an enhanced fusion rate and minimized revision risk, with no increase in the risk of subsidence.

The neurofibromatosis type 1 (NF1) RASopathy is associated with persistent fibrotic nonunions (pseudarthrosis) in human and mouse skeletal tissue. Here, we performed spatial transcriptomics to define the molecular signatures occurring during normal endochondral healing following fracture in mice. Within the control fracture callus, we observed spatially restricted activation of morphogenetic pathways, such as TGF-β, WNT, and BMP. To investigate the molecular mechanisms contributing to Nf1-deficient delayed fracture healing, we performed spatial transcriptomic analysis on a Postn-cre;Nf1fl/- (Nf1Postn) fracture callus. Transcriptional analyses, subsequently confirmed through phospho-SMAD1/5/8 immunohistochemistry, demonstrated a lack of BMP pathway induction in Nf1Postn mice. To gain further insight into the human condition, we performed spatial transcriptomic analysis of fracture pseudarthrosis tissue from a patient with NF1. Analyses detected increased MAPK signaling at the fibrocartilaginous-osseus junction. Similar to that in the Nf1Postn fracture, BMP pathway activation was absent within the pseudarthrosis tissue. Our results demonstrate the feasibility of delineating the molecular and tissue-specific heterogeneity inherent in complex regenerative processes, such as fracture healing, and reconstructing phase transitions representing endochondral bone formation in vivo. Furthermore, our results provide in situ molecular evidence of impaired BMP signaling underlying NF1 pseudarthrosis, potentially informing the clinical relevance of off-label BMP2 as a therapeutic intervention.