Influence Bone Healing Research Articles

Polydeoxyribonucleotides Pre-Clinical Findings in Bone Healing: A Scoping Review.

Polydeoxyribonucleotide (PDRN) is a chain-like polymer derived from DNA. Recent in vitro and animal studies have showcased the beneficial impacts of PDRN on the process of bone mending, whether used on its own or in conjunction with other substances that aid in regeneration. This scoping review aims to synthesize the current understanding of how PDRNs influence bone healing. The studies included in the screening procedure were randomized controlled clinical trials (RCTs), both retrospective and prospective case-control studies, as well as in vitro and in vivo investigations. Articles were sourced from PubMed (MEDLINE), Scopus, EMBASE, Web of Science, and Google Scholar electronic databases using the following MeSH terms: (polydeoxyribonucleotide) and (bone) and (regeneration). Initially, 228 articles were identified. Following the review process, a total of eight studies were ultimately examined. Among these, two were confined to laboratory studies, five were conducted on living organisms, and one encompassed both evaluations on living organisms and in vitro assessments. A descriptive qualitative approach was employed to present the data extracted from the studies that were included. PDRN has the potential to enhance the process of bone healing and the quantity of newly generated bone when combined with grafting materials. Future clinical studies are warranted to ascertain the appropriate clinical application of PDRN based on the dosage under consideration.

Does early post-operative exercise influence bone healing kinetics? Preclinical evaluation of non-critical sized femur defect healing.

Physical exercise is a well-known modality for maintaining healthy locomotor mechanism. A detailed preclinical research on physical exercise effect on bone healing kinetics could help to improve the rehabilitation process after fracture treatment and bone remodeling. Our aim was to evaluate the effect of early post-operative exercise effect on bone microstructural changes in a rat model. Twenty Sprague Dawley male rats underwent bi-cortical 1.6mm hole drilling in both femur diaphysis, after which (n=10) underwent continuous treadmill training (TR) over two weeks, while the other group of rats (n=10) was assigned to non-training (NT) control group. New bone formation labeling was performed by subcutaneous fluorochrome injections at day 5, 14 and 31. In vivo micro-computed tomography (μCT) scans were performed once a week during the 6-week post-operative period. Ten animals (five from each group) were euthanized at 3rd week while remaining animals were euthanized at 6th week. Femur samples were extracted and underwent ex vivo μCT and histological evaluation, while serum was used for evaluating alkaline phosphatase (ALP). μCT data demonstrated increased volume and surface of newly formed bone in defect area of TR group. Bone volume/Tissue volume (BV/TV) ratio and number of osteocytes showed an increase in TR group after 3-week period. Fluorochrome distances were increased between day 5 and 14 within the training group. Serum ALP level increased in both groups over 3- and 6-weeks. Post-operative exercise increases the bone healing kinetics and stimulates the new bone formation during and after the training protocol has ended.

BONE DEFECT HEALING USING THE INDUCED MEMBRANE TECHNIQUE AFTER CHRONICALLY INFECTED NONUNION IN A NOVEL RABBIT MODEL

In chronically infected fracture non-unions, treatment requires extensive debridement to remove necrotic and infected bone, often resulting in large defects requiring elaborate and prolonged bone reconstruction. One approach includes the induced membrane technique (IMT), although the differences in outcome between infected and non-infectious aetiologies remain unclear. Here we present a new rabbit humerus model for IMT secondary to infection, and, furthermore, we compare bone healing in rabbits with a chronically infected non-union compared to non-infected equivalents.A 5 mm defect was created in the humerus and filled with a polymethylmethacrylate (PMMA) spacer or left empty (n=6 per group). After 3 weeks, the PMMA spacer was replaced with a beta-tricalcium phosphate (chronOs, Synthes) scaffold, which was placed within the induced membrane and observed for a further 10 weeks. The same protocol was followed for the infected group, except that four week prior to treatment, the wound was inoculated with Staphylococcus aureus (4×106 CFU/animal) and the PMMA spacer was loaded with gentamicin, and systemic therapy was applied for 4 weeks prior to chronOs application.All the animals from the infected group were culture positive during the first revision surgery (mean 3×105 CFU/animal, n= 12), while at the second revision, after antibiotic therapy, all the animals were culture negative. The differences in bone healing between the non-infected and infected groups were evaluated by radiography and histology. The initially infected animals showed impaired bone healing at euthanasia, and some remnants of bacteria in histology. The non-infected animals reached bone bridging in both empty and chronOs conditions.We developed a preclinical in vivo model to investigate how bacterial infection influence bone healing in large defects with the future aim to explore new treatment concepts of infected non-union.

Role of hormones in bone remodeling in the craniofacial complex: A review.

Diseases such as periodontitis and osteoporosis are expected to rise tremendously by 2050. Bone formation and remodeling are complex processes that are disturbed in a variety of diseases influenced by various hormones. This study aimed to review and present the roles of various hormones that regulate bone remodeling of the craniofacial complex. A literature search was conducted on PubMed and Google Scholar for studies related to hormones and jawbone. Search strategies included the combinations ("name of hormone"+"dental term") of the following terms: "hormones", "oxytocin", "estrogen", "adiponectin", "parathyroid hormone", "testosterone", "insulin", "angiotensin", "cortisol", and "erythropoietin", combined with a dental term "jaw bone", "alveolar bone", "dental implant", "jaw+bone regeneration, healing or repair", "dentistry", "periodontitis", "dry socket", "osteoporosis" or "alveolitis". The papers were screened according to the inclusion criteria from January 1, 2000 to March 31, 2021 in English. Publications included reviews, book chapters, and original research papers; in vitro studies, in vivo animal, or human studies, including clinical studies, and meta-analyses. Bone formation and remodeling is a complex continuous process involving many hormones. Bone volume reduction following tooth extractions and bone diseases, such as periodontitis and osteoporosis, cause serious problems and require a great understanding of the process. Hormones are with us all the time, shape our development and regulate homeostasis. Newly discovered effects of hormones influencing bone healing open the possibilities of using hormones as therapeutics to combat bone-related diseases.

IC-Type Electric stimulation for delayed bone healing: monocentric evaluation over eight years of experience.

Electrostimulation is suggested to positively influence bone healing for delayed unions of both fractures and osteotomies. This monocentric series aims to retrospectively assess the outcome of electrostimulation treatment for delayed union after traumatic fractures or knee osteotomy. Patients treated with electrostimulation for delayed union (no bony union on radiographic imaging at 90 days after osteotomy or fracture treatment) over an 8-year period were screened. The delay of treatment, success rate, revision rate and demographic data (age, sex, location of fracture, presence of osteosynthesis materials) were investigated. A questionnaire assessed objective (nicotine abuse, NRS pain assessment, activity levels) and subjective (comfort, usability, cost-effectiveness) aspects. Electrostimulation delivered radiographic healing in 75% of the fracture group and 66% of the osteotomy group. No statistical significant difference (N=136) in success rate was found for age, sex, presence of osteosynthesis material, delay or fracture location. Success rate did differ significantly with pain, activity level and smoking (p<0.05). Reflective questions to patients were answered mostly positively. The use of electrostimulation for the delayed union of fractures and knee osteotomies delivers high healing rates avoiding the burden of surgical reintervention. It is generally well received by the patient. No difference in success rate was found between sex, age or fracture location, nor did the delay of therapy onset or presence of osteosynthesis material seem to affect the success rate. Smoking had a negative influence on the efficacy of bone electrostimulation.

Effects of Obesity on Bone Healing in Rats.

Although the association between periodontitis and obesity is well explored, it is unclear whether obesity is associated with a worse therapeutic outcome after periodontal treatment. The aim of this study was to investigate the effects of obesity on bone healing with and without the application of regeneration-promoting molecules. A standardized bone fenestration-type defect was created over the root of the mandibular first molar in 15 Wistar rats. Ten animals received a high-fat, high-sucrose diet (HFSD), while the remaining five animals were fed a standard diet. During surgery, the fenestration defects from half of the HFSD-fed, i.e., obese animals, were treated with regeneration-promoting molecules (enamel matrix derivative; EMD). After four weeks, bone healing was evaluated by histomorphometry, TRAP staining and immunohistochemistry for RUNX2 and osteopontin. The analyses revealed that the spontaneous healing of the periodontal defects was compromised by obesity. Application of EMD partially compensated for the negative effect of obesity. Nevertheless, EMD-stimulated bone healing in obese animals was not better than the spontaneous healing in the obesity-free control group, indicating that obesity may also inhibit the stimulatory effects of regeneration-promoting molecules. Our results show that obesity can negatively influence bone healing and suggest that bone healing may be compromised in humans.

Effects of immune cells on mesenchymal stem cells during fracture healing.

In vertebrates, bone is considered an osteoimmune system which encompasses functions of a locomotive organ, a mineral reservoir, a hormonal organ, a stem cell pool and a cradle for immune cells. This osteoimmune system is based on cooperatively acting bone and immune cells, cohabitating within the bone marrow. They are highly interdependent, a fact that is confounded by shared progenitors, mediators, and signaling pathways. Successful fracture healing requires the participation of all the precursors, immune and bone cells found in the osteoimmune system. Recent evidence demonstrated that changes of the immune cell composition and function may negatively influence bone healing. In this review, first the interplay between different immune cell types and osteoprogenitor cells will be elaborated more closely. The separate paragraphs focus on the specific cell types, starting with the cells of the innate immune response followed by cells of the adaptive immune response, and the complement system as mediator between them. Finally, a brief overview on the challenges of preclinical testing of immune-based therapeutic strategies to support fracture healing will be given.

Engineer design process assisted by explainable deep learning network

Engineering simulation accelerates the development of reliable and repeatable design processes in various domains. However, the computing resource consumption is dramatically raised in the whole development processes. Making the most of these simulation data becomes more and more important in modern industrial product design. In the present study, we proposed a workflow comprised of a series of machine learning algorithms (mainly deep neuron networks) to be an alternative to the numerical simulation. We have applied the workflow to the field of dental implant design process. The process is based on a complex, time-dependent, multi-physical biomechanical theory, known as mechano-regulatory method. It has been used to evaluate the performance of dental implants and to assess the tissue recovery after the oral surgery procedures. We provided a deep learning network (DLN) with calibrated simulation data that came from different simulation conditions with experimental verification. The DLN achieves nearly exact result of simulated bone healing history around implants. The correlation of the predicted essential physical properties of surrounding bones (e.g. strain and fluid velocity) and performance indexes of implants (e.g. bone area and bone-implant contact) were greater than 0.980 and 0.947, respectively. The testing AUC values for the classification of each tissue phenotype were ranging from 0.90 to 0.99. The DLN reduced hours of simulation time to seconds. Moreover, our DLN is explainable via Deep Taylor decomposition, suggesting that the transverse fluid velocity, upper and lower parts of dental implants are the keys that influence bone healing and the distribution of tissue phenotypes the most. Many examples of commercial dental implants with designs which follow these design strategies can be found. This work demonstrates that DLN with proper network design is capable to replace complex, time-dependent, multi-physical models/theories, as well as to reveal the underlying features without prior professional knowledge.

Influence de l’âge sur la consolidation osseuse après un allongement des membres par une méthode intramédullaire

BackgroundDistraction osteogenesis with an intramedullary motorized nail is a well-established method to treat leg length discrepancy (LLD). The complex process of bone consolidation is affected by age, location, co-morbidities, smoking and gender. The purpose of this case series was to investigate influencing factors in bone regeneration after intramedullary callus distraction. HypothesisAdvanced age influences the outcome of intramedullary limb lengthening. Patients and methodsThis retrospective analysis included 19 patients after intramedullary telescopic nailing (PRECICE) on the lower limb with a mean age of 43 years. Bone healing was assessed by distraction and healing parameters such as distraction-consolidation time (DCT), distraction index (DI), healing index (HI), lengthening index (LI), and consolidation index (CI). ResultsConfounding factors such as smoking, previous operations on the treated bone, but also the occurrence of complications, and the number of revision surgeries are independent of the patients’ age. Younger patients showed a shorter distraction distance, a lower DCT, a lower DI, a higher HI, and a higher CI than older patients. The complication rate requiring nail exchange was higher among the younger patients. Bony healing was observed in all age groups treated with a telescopic nail regardless of age. ConclusionAdvanced age did not influence bone healing or complication rate in intramedullary lengthening. However, the conclusion is limited by the small patient number. Level of evidenceIV; case control study.

Prevalence and risk factors for pseudarthrosis in humeral shaft fractures treated by minimally invasive plate osteosynthesis: A 10-year review.

Fractures of the humeral shaft account for about 3% to 5% of all fractures. Although conservative treatment remains the first choice, there are a number of surgical indications. Minimally invasive plate osteosynthesis shows good functional results. However, complications have been reported, such as non-union. To assess the prevalence and risk factors for non-union after treatment of humeral shaft fractures using minimally invasive plate osteosynthesis. This retrospective study was carried out in patients treated by minimally invasive plate osteosynthesis between 2009 and 2019. Demographic data and variables related to the fracture that could influence bone healing were analysed. The unpaired t-test and Mann-Whitney test were used for the statistical analyses. Categorical variables were analysed using the chi-square test or Fisher's exact test. The study population showed a male predominance (53 of 75, 70.7%). The average time for fracture healing was 19.8 ± 15.3 weeks. Seven patients developed non-union. Only the presence of an open fracture increased the likelihood of non-union. The prevalence of non-union in patients treated by minimally invasive plate osteosynthesis was 9.3%. Patients with open fractures were six times more likely to progress to non-union. Fracture characteristics (Arbeitsgemeinschaft für Osteosynthesefragen classification, fracture location and plate working length) did not influence progression to non-union.

The influence of advanced age in bone healing after intramedullary limb lengthening

BackgroundDistraction osteogenesis with an intramedullary motorized nail is a well-established method to treat leg length discrepancy (LLD). The complex process of bone consolidation is affected by age, location, comorbidities, smoking and gender. The purpose of this case series was to investigate influencing factors in bone regeneration after intramedullary callus distraction. HypothesisAdvanced age influences the outcome of intramedullary limb lengthening. Patients and methodsThis retrospective analysis included 19 patients after intramedullary telescopic nailing (PRECICE) on the lower limb with a mean age of 43 years. Bone healing was assessed by distraction and healing parameters such as distraction-consolidation time (DCT), distraction index (DI), healing index (HI), lengthening index (LI), and consolidation index (CI). ResultsConfounding factors such as smoking, previous operations on the treated bone, but also the occurrence of complications, and the number of revision surgeries are independent of the patients’ age. Younger patients showed a shorter distraction distance, a lower DCT, a lower DI, a higher HI, and a higher CI than older patients. The complication rate requiring nail exchange was higher among the younger patients. Bony healing was observed in all age groups treated with a telescopic nail regardless of age. ConclusionAdvanced age did not influence bone healing or complication rate in intramedullary lengthening. However, the conclusion is limited by the small patient number. Level of evidenceIV; Case control study.

Preliminary Clinical and Radiographic Evaluation of a Novel Resorbable Implant of Polylactic Acid (PLA) for Tibial Tuberosity Advancement (TTA) by Modified Maquet Technique (MMT).

Simple SummaryThe metallic implants carry many problems as infections, bone resorption, pain at the site, etc. Removing these metallic implants is an expensive procedure, and it entails risks. Due to the costs, the most common in veterinary medicine is to remove metallic implants only when a problem occurs. The rupture of the cranial cruciate ligament (RCrCL) is the most common orthopedic pathology in dogs and the most frequent cause of arthrosis, pain, and limp on the knee joint. Those are the reasons that encouraged us to develop a new type of biodegradable implant comprised of polylactic acid (PLA). This is a non-toxic material that can be eliminated by natural metabolic pathways and use the PLA implant in tibial tuberosity advancement (TTA), which is a technique for the resolution of RCrCL in dogs. In our study, PLA implants for TTA provide good functional results, presenting an acceptable number of complications. The implants show a faster ossification than metallic implants, which was not affected by age or by body weight. The PLA implants have a clinical recovery time similar to metallic implants.Our objectives were to determine whether PLA implants can be used in TTA with successful results; secondly, to observe whether they provide a faster bone healing; finally, to determine whether weight or age influences bone healing scores. PLA cages were created with a 3D printer. TTA by MMT with PLA implants was performed in 24 patients. Follow-ups were carried out pre-surgical, at 1, 2, and 5 months and consisted of a radiographic study and a lameness assessment. A comparison was performed in terms of weight and age. Patients data, time between follow-up examinations, healing score, and lameness score were compared between patients using commercial software for statistically significant differences p < 0.05. Eighteen dogs finished the study. The ossification degrees presented statistically significant differences between each other. PLA implants maintained the advancement in 100% of cases. Comparing weight and age did not present any statistically significant differences between groups. Lameness presented statistically significant differences between follow-up examinations. Complications were observed in 20.8%. PLA implants for TTA provide good functional results, presenting an acceptable rate of complications. They provide a faster bone healing of the osteotomy gap, which was not affected by age or body weight, and have a clinical recovery time similar to metallic implants.

Gut microbial-derived short-chain fatty acids and bone: a potential role in fracture healing.

Bone healing complications such as delayed healing or non-union affect 5-10 % of patients with a long-bone fracture and lead to reduced quality of life and increased health-care costs. The gut microbiota and the metabolites they produce, mainly short-chain fatty acids (SCFAs), have been shown to impact nearly all organs of the human body including bone. SCFAs show broad activity in positively influencing bone healing outcomes either by acting directly on cell types involved in fracture healing, such as osteoblasts, osteoclasts, chondrocytes and fibroblasts, or indirectly, by shaping an appropriate anti-inflammatory and immune regulatory response. Due to the ability of SCFAs to influence osteoblast and osteoclast differentiation, SCFAs may also affect the integration of orthopaedic implants in bone. In addition, SCFA-derivatives have already been used in a variety of tissue engineering constructs to reduce inflammation and induce bone tissue production. The present review summarises the current knowledge on the role of the gut microbiota, in particular through the action of SCFAs, in the individual stages of bone healing and provides insights into how SCFAs may be utilised in a manner beneficial for fracture healing and surgical reconstruction.

Midshaft Clavicle Fractures Treated Nonoperatively Using Figure-of-Eight Bandage: Are Fracture Type, Shortening, and Displacement Radiographic Predictors of Failure?

As there are no clear and unique radiographic predictors of healing disturbances for acute midshaft clavicle fractures, their treatment is still controversial. The aim of the study was to evaluate in midshaft clavicle fractures treated nonoperatively if fracture type (FT), shortening, and displacement, assessed before and after figure-of-eight bandage (F8-B) application, could be considered prognostic factors of delayed union and nonunion. One hundred twenty-two adult patients presenting a closed displaced midshaft clavicle fracture, managed nonoperatively with an F8-B, were enrolled. FT, initial shortening (IS), and initial displacement (ID) were radiographically evaluated at diagnosis, and both residual shortening (RS) and displacement (RD) were measured after F8-B application. The patients were followed up 1, 3, 6, and 12 months post-injury. Multivariate statistical analysis was performed. RD should be considered as radiological predictor of sequelae. Further, an RD equal to 104% of clavicle width was identified as an optimal cut-off point to distinguish between healed and unhealed fractures, and 140% between delayed union and nonunion. Our data pointed out the effectiveness of the F8-B in reducing fracture fragments and restoring clavicular length. In midshaft clavicle fractures of adults, fracture comminution and clavicular shortening did not influence bone healing. On the contrary, RD has been shown as the most likely predictor of both delayed union and nonunion.

Impact of Janus Kinase Inhibition with Tofacitinib on Fundamental Processes of Bone Healing.

Both inflammatory diseases like rheumatoid arthritis (RA) and anti-inflammatory treatment of RA with glucocorticoids (GCs) or non-steroidal anti-inflammatory drugs (NSAIDs) negatively influence bone metabolism and fracture healing. Janus kinase (JAK) inhibition with tofacitinib has been demonstrated to act as a potent anti-inflammatory therapeutic agent in the treatment of RA, but its impact on the fundamental processes of bone regeneration is currently controversially discussed and at least in part elusive. Therefore, in this study, we aimed to examine the effects of tofacitinib on processes of bone healing focusing on recruitment of human mesenchymal stromal cells (hMSCs) into the inflammatory microenvironment of the fracture gap, chondrogenesis, osteogenesis and osteoclastogenesis. We performed our analyses under conditions of reduced oxygen availability in order to mimic the in vivo situation of the fracture gap most optimal. We demonstrate that tofacitinib dose-dependently promotes the recruitment of hMSCs under hypoxia but inhibits recruitment of hMSCs under normoxia. With regard to the chondrogenic differentiation of hMSCs, we demonstrate that tofacitinib does not inhibit survival at therapeutically relevant doses of 10–100 nM. Moreover, tofacitinib dose-dependently enhances osteogenic differentiation of hMSCs and reduces osteoclast differentiation and activity. We conclude from our data that tofacitinib may influence bone healing by promotion of hMSC recruitment into the hypoxic microenvironment of the fracture gap but does not interfere with the cartilaginous phase of the soft callus phase of fracture healing process. We assume that tofacitinib may promote bone formation and reduce bone resorption, which could in part explain the positive impact of tofacitinib on bone erosions in RA. Thus, we hypothesize that it will be unnecessary to stop this medication in case of fracture and suggest that positive effects on osteoporosis are likely.

Factors Influencing Bone Healing after Extirpation with Endodontic Microsurgery-Microscopic Apicoectomy for Extensive Radicular Cysts

Factors Influencing Bone Healing after Extirpation with Endodontic Microsurgery-Microscopic Apicoectomy for Extensive Radicular Cysts

Corrective osteotomies of femur and tibia: which factors influence bone healing?

Corrective osteotomies of the lower limb are standard procedures in orthopedic surgery. Still, there is only limited research on factors affecting bone healing after osteotomies. We hypothesize that especially the location of the osteotomy, smoking status and BMI affect bone healing. The healing process of 547 patients who underwent osteotomies of the lower limb (259 female, 288 male; average 40.6years, range 14-77) was evaluated. To assess bone healing, participants were divided into three groups by bone healing duration ( < 5/5-8/ > 8months). Differences in healing duration related to the anatomic level of the osteotomy (diaphysis vs. metaphysis), age, gender, smoking status, BMI, and modus of the osteotomy (open vs. closed wedge) were tested for significance using an ordinal regression analysis. A significant correlation between bone healing and the anatomical level of the osteotomy on femur and tibia and the patients' smoking status was found. The odds of the diaphysis considering bone healing was 0.187 (95% CI, 0.08-0.44) times that of the metaphysis (Wald χ2(1) = 14.597, p < 0.000). The odds ratio of smokers considering bone healing was 0.192 (95% CI, 0.11-0.33) times that of non-smokers (Wald χ2(1) = 35.420, p < 0.000). All other analyzed factors did not show a significant correlation with bone healing. Smoking status and the localization of the osteotomy on femur and tibia (diaphysis vs. metaphysis) are significantly correlated with bone healing duration. In line with current literature emphasizing the detrimental effect of smoking on bone healing, our findings should encourage surgeons to think twice about the indication to perform osteotomies on smokers. Furthermore, if applicable, osteotomies should be performed in the metaphyseal areas of femur and tibia.

Influence of surface modifications on the degradation of standard-sized magnesium plates and healing of mandibular osteotomies in miniature pigs

Biodegradable magnesium alloys are suitable osteosynthesis materials. Despite the alloy composition, surface modifications appear to have an influence on the degradation process and biocompatibility. The aim of this study was to investigate the impact of hydrogenation and fluoridation of the surface in a mandibular osteotomy model. Standard-sized plates and screws were implanted in an osteotomy at the mandibular angle in nine miniature pigs. The plates and screws were harvested together with the adjacent tissues at 8 weeks after surgery and were investigated by micro-computed tomography and histological analysis. The bone healing of the osteotomy was undisturbed, independent of the surface properties. The adjacent bone tissue showed new bone formation at the implant surface; however, formation of some lacunae could be observed. The corrosion was between 9.8% and 11.6% (fluoridated<hydrogenated<non-modified) in histological specimens, while radiologically neither the volume nor the density of the osteosynthesis material was reduced in any treatment group. The soft tissues exhibited full biocompatibility with every surface property. In summary, surface modification by hydrogenation and fluoridation did not significantly influence bone healing, biocompatibility, or corrosion kinetics of the magnesium osteosynthesis at the mandibular angle.

Influence of hormone or hormone replacement therapy on bone healing

Since the observations of Fuller Albright in 1940, it is well documented that estrogen deficiency is one of the major causes of osteoporosis. Osteoporosis increases not only the risk of fracture and consecutively the number of fractures but can also induce a disorder of fracture healing. This raises the question whether estrogen deficiency negatively influences bone healing in addition to fragility. The currently available literature on this topic provides indications that estrogen deficiency negatively influences fracture healing in the various stages of healing. Furthermore, there is evidence that the administration of estrogen antagonizes these negative effects. Future clinical investigations are needed to find out whether the experimental data can be transferred to the patients.

Identification of risk factors affecting bone formation in gradual ulnar lengthening in children with hereditary multiple exostoses: A retrospective study.

The forearm deformity classified by Masada is a characteristic trait of patients with hereditary multiple exostoses (HME). Ulnar gradual lengthening, which was considered to be a safe and reliable procedure, was popular in treating these difficult deformities, however, delayed consolidation of the callus is uncommon but not rare in literature review. The purpose of this study was to try to identify the risk factors influencing bone healing in gradual ulnar lengthening in HME.We retrospectively reviewed patients with HME-induced forearm deformity who underwent gradual ulnar lengthening at our hospital from 2010 to 2016. Patients’ demographic data, forearm deformity of Masada type, surgical procedure, ulnar diameter of osteotomy site, and external fixator type were recorded. We also reviewed radiographical data included gained length, axis deviation, callus form. Clinical outcome was assessed by the bone healing index (HI). Multiple linear regression was used to analyze the relationships between diffident parameters and the HI, the level of significance was set P <.05.Thirty-three patients were included in this study. The mean follow-up period was 1.5 (range 0.5–8) years. Circular external fixators were used in 5 patients and monolateral external fixators were used in 28 patients. The mean achieved length was 4.24 cm. The mean HI was 50.3 (range 26.6–99.3) days/cm. In patient with monolateral external fixator, patient's age was positively correlated with the bone HI (P = .001), while diameter and body mass index (BMI) were negatively correlated with the HI (P = .040, .018, respectively). Patient's sex, removal of distal ulnar exostoses, lengthening percentage, and axis deviation were non-significant in the regression model.When using monolateral external fixator for ulnar lengthening, patient's age, diameter of osteotomy site, and BMI are the most important risk factors related to bone formation. Pediatric orthopedic surgeons should consider these variables in order to avoid delayed union.