Emerging trends in the application of hydrogel-based biomaterials for enhanced wound healing: A literature review.

Currently, there is a rising global incidence of diverse acute and chronic wounds, underscoring the immediate necessity for research and treatment advancements in wound repair. Hydrogels have emerged as promising materials for wound healing due to their unique physical and chemical properties. This review explores the classification and characteristics of hydrogel dressings, innovative preparation strategies, and advancements in delivering and releasing bioactive substances. Furthermore, it delves into the functional applications of hydrogels in wound healing, encompassing areas such as infection prevention, rapid hemostasis and adhesion adaptation, inflammation control and immune regulation, granulation tissue formation, re-epithelialization, and scar prevention and treatment. The mechanisms of action of various functional hydrogels are also discussed. Finally, this article also addresses the current limitations of hydrogels and provides insights into their potential future applications and upcoming innovative designs.

The capacity of exosomes derived from adipose-derived stem cells to enhance wound healing in diabetes.

The slow healing and nonhealing of diabetic wounds have long posed challenges for clinical practitioners. In the presence of elevated glucose levels, the body's regulatory mechanisms undergo alterations that impede normal wound healing processes, including cell proliferation, cytokine release, and growth factor activity. Consequently, the advancement of stem cell technology has sparked growing interest in utilizing stem cells and their derivatives as potential therapeutic agents to enhance diabetic wound healing. This paper aims to provide an academic review of the therapeutic effects of adipose-derived stem cell-EXOs (ADSC-EXOs) in diabetic wound healing. As a cell-free therapy, exosomes (EXOs) possess a multitude of proteins and growth factors that have been shown to be advantageous in promoting wound healing and mitigating the potential risks associated with stem cell therapy. By examining the current knowledge on ADSC-EXOs, this review seeks to offer insights and guidance for the potential application of EXOs in the treatment of diabetic wounds.

The physiological phenomenon and regulation of macrophage polarization in diabetic wound.

Macrophages play a crucial role in regulating wound healing, as they undergo a transition from the proinflammatory M1 phenotype to the proliferative M2 phenotype, ultimately contributing to a favorable outcome. However, in hyperglycemic and hyper-reactive oxygen species environments, the polarization of macrophages becomes dysregulated, hindering the transition from the inflammatory to proliferative phase and consequently delaying the wound healing process. Consequently, regulating macrophage polarization is often regarded as a potential target for the treatment of diabetic wounds. The role of macrophages in wound healing and the changes in macrophages in diabetic conditions were discussed in this review. After that, we provide a discussion of recent therapeutic strategies for diabetic wounds that utilize macrophage polarization. Furthermore, this review also provides a comprehensive summary of the efficacious treatment strategies aimed at enhancing diabetic wound healing through the regulation of macrophage polarization. By encompassing a thorough understanding of the fundamental principles and their practical implementation, the advancement of treatment strategies for diabetic wounds can be further facilitated.

High-fat diet causes undesirable bone regeneration by altering the bone marrow environment in rats.

Objective: Diet structure has changed greatly over the last few decades, and high-calorie diets have become an integral part of people's daily diet, as well as the important cause of obesity in society. Several organ systems, including the skeletal system, are seriously affected by high-fat-diets (HFD) in the world. There is, however, still a lack of knowledge about the effects of HFD on bone regeneration and the possible mechanisms involved. In this study, the difference in bone regeneration between rats under HFD and low-fat-diets (LFD) was evaluated by monitoring the process of bone regeneration in distraction osteogenesis (DO) model animals, as well as the possible mechanisms. Methods: A total of 40 Sprague Dawley (SD) rats (5 weeks old) were randomly divided into HFD group (n=20) and LFD group (n=20). Except for feeding methods, there were no differences between the two groups in terms of treatment conditions. All animals received the DO surgery eight weeks after starting to feed. After a delay of 5 days (latency phase), the active lengthening phase was performed for 10 days (0.25 mm/12 h), and the consolidation phase followed for 42 days. An observational study of bone included radioscopy (once a week), micro-computed tomography (CT), general morphology, biomechanics, histomorphometry, and immunohistochemistry. Result: The results showed that HFD group had a higher body weight than LFD group after 8, 14, and 16 weeks of feeding. Furthermore, at the final observation, there were statistically significant differences between LFD group and HFD group in terms of total cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels. Additionally, observations on bone regeneration showed a slower regeneration and a lower biomechanical strength in HFD group than LFD group, based on radiography, micro-CT, general morphology, biomechanics, histomorphometry, and immunohistochemistry. Conclusion: In this study, HFD resulted in elevated blood lipids, increased adipose differentiation at the bone marrow level, and delayed bone regeneration. The pieces of evidence are beneficial to better understand the association between diet and bone regeneration and to adjust the diet optimally for fracture patients.

Mechanisms of Nrf2 and NF-κB pathways in diabetic wound and potential treatment strategies.

The issue of delayed wound healing or nonhealing in diabetic patients presents a challenge for modern medicine. A number of attempts have been made to understand the mechanisms behind diabetic wound. In a hyperglycemic environment, increased intracellular reactive oxygen species (ROS) disturb the balance between oxidation and antioxidant, causing the wound environment to deteriorate. It has been established that the nuclear factor E2-related factor 2 (Nrf2) and nuclear factor-kappa B (NF-κB) pathways play an important role in regulating inflammation and oxidative stress. Several potential treatment strategies involving Nrf2 and/or NF-κB pathways have been explored in previous studies. Hence, we analyzed mechanisms and changes in Nrf2 and NF-κB pathways in response to oxidative stress and inflammation in diabetic environment. Additionally, we reviewed potential treatment strategies from the past five years for diabetic wound by Nrf2 and/or NF-κB pathways, including receptor agonists, vitamins, hormones, exosomes, drugs, plants, and biomaterials. It may be useful to develop drugs to promote diabetic wound healing.

Diabetes mellitus impairs bone regeneration and biomechanics.

BACKGROUND: With the rise of high-calorie diets and the aging of populations, the incidence of diabetes was increased dramatically in the world and the number of people with diabetes was predicted to rise to 600 million by 2045. Numerous studies have confirmed that several organ systems, including the skeletal system, are seriously affected by diabetes. In that study, the bone regeneration and the biomechanics of the newly regenerated bone were investigated in diabetic rats, which may provide a supplement for previous studies. METHODS: A total of 40 SD rats were randomly divided into the type 2 diabetes mellitus (T2DM) group (n = 20) and the control group (n = 20). Beyond that high fat diet and streptozotocin (STZ) were jointly used in the T2DM group, there were no differences between the two groups in terms of treatment conditions. Distraction osteogenesis was used in all animals for the next experimental observation. The evaluation criterion of the regenerated bone was based on radioscopy (once a week), micro-computed tomography (CT), general morphology, biomechanics (including ultimate load, modulus of elasticity, energy to failure, and stiffness), histomorphometry (including von Kossa, Masson trichrome, Goldner trichrome, and safranin O staining), and immunohistochemistry. RESULTS: All rats in the T2DM group with fasting glucose levels (FGL, > 16.7 mmol/L) were allowed to complete the following experiments. The results showed that rats with T2DM have a higher body weight (549.01 g ± 31.34 g) than rats in the control group (488.60 g ± 33.60 g) at the end of observation. Additionally, compared to the control group, slower bone regeneration in the distracted segments was observed in the T2DM group according to radiography, micro-CT, general morphology, and histomorphometry. Furthermore, a biomechanical test showed that there was a worse ultimate load (31.01 ± 3.39%), modulus of elasticity (34.44 ± 5.06%), energy to failure (27.42 ± 5.87%), and stiffness (34.55 ± 7.66%) than the control group (45.85 ± 7.61%, 54.38 ± 9.33%, 59.41 ± 10.96%, and 54.07 ± 9.30%, respectively). Furthermore, the decreased expressions of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) were presented in T2DM group by immunohistochemistry. CONCLUSION: The present study demonstrated that diabetes mellitus impairs bone regeneration and biomechanics in newly regenerated bone, a phenomenon that might be related to oxidative stress and poor angiogenesis brought on by the disease.

Bone Defects in Tibia Managed by the Bifocal vs. Trifocal Bone Transport Technique: A Retrospective Comparative Study.

Background: The purpose of this study is to evaluate the clinical effectiveness and determine the differences, if any, between the trifocal bone transport (TFT) technique and the bifocal bone transport (BFT) technique in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator. Methods: A total of 53 consecutive patients with long segmental tibial bone defects caused by infection and treated by monolateral rail external fixator in our department were retrospectively collected and analyzed from the period January 2013 to April 2019, including 39 males and 14 females with an average age of 38.8 ± 12.4 years (range 19-65 years). Out of these, 32 patients were treated by the BFT technique, and the remaining 21 patients were managed by the TFT technique. The demographic data, operation duration (OD), docking time (DT), external fixation time (EFT), and external fixation index (EFI) were documented and analyzed. Difficulties that occur during the treatment were classified according to Paley. The clinical outcomes were evaluated by following the Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria at the last clinical visit. Results: All patients achieved an infection-free union finally, and there was no significant difference between the two groups in terms of demographic data and both ASAMI bone and functional scores (p > 0.05). The mean defect size and OD in TFT (9.4 ± 1.5 cm, 161.9 ± 8.9 min) were larger than that in BFT (7.8 ± 1.8 cm, 122.5 ± 11.2 min) (p < 0.05). The mean DT, EFT, and EFI in TFT (65.9 ± 10.8 days, 328.0 ± 57.2 days, 34.8 ± 2.1 days/cm) were all less than those in BFT (96.8 ± 22.6 days, 474.5 ± 103.2 days, 60.8 ± 1.9 days/cm) (p < 0.05). Difficulties and complications were more prevalent in the BFT group than in the TFT group (p < 0.05). Conclusion: Both the trifocal and BFT techniques achieve satisfactory clinical outcomes in the reconstruction of long segmental tibial bone defects caused by infection using a monolateral rail external fixator. The TFT technique can significantly decrease the DT, EFT, EFI, difficulties, and complications compared with the BFT technique.

Retrospective clinical outcomes in the definitive treatment of high-energy tibial diaphyseal fractures using hexapod external fixator versus monolateral external fixator.

BACKGROUND: External fixation, which can preserve the biomechanical microenvironment of fracture healing, plays an important role in managing the high-energy fractures with poor surrounding soft tissues. The purpose of this study was to determine the differences of clinical outcomes, if any, between hexapod external fixator and monolateral external fixator in the definitive treatment of high-energy tibial diaphyseal fractures. METHODS: A total of 53 patients with high-energy tibial diaphyseal fractures and definitively treated by the hexapod external fixator (HEF) or monolateral external fixator (MEF) were retrospectively collected and analyzed, from March 2015 to June 2019. There were 31 patients in the HEF treatment, and the other 22 patients were managed by the MEF. The demographic data, surgical duration, external fixation time, final radiological results, complications, and clinical outcomes were documented and analyzed. Difficulties that occurred during the treatment were classified according to Paley. The clinical outcomes were evaluated by the Association for the Study and Application of the Method of Ilizarov criteria (ASAMI) at the last clinical visit. RESULTS: The mean surgical duration in the HEF group (62.4 ± 8.3 min) was shorter than that in the MEF group (91.4 ± 6.9 min) (P < 0.05). All patients acquired complete bone union finally. Patients in the HEF group (24.2 ± 3.1 weeks) underwent a shorter average external fixation time than that in the MEF group (26.3 ± 3.8 weeks) (P < 0.05). Satisfactory alignment was achieved in all patients without the need for remanipulation. The residual sagittal plane deformities in the HEF group were all less than that in the MEF group (P < 0.05). The complication rate was 35.5% in the HEF group, while 45.5% in the MEF group. There was no statistically significant difference between the two groups in ASAMI scores (P > 0.05). CONCLUSION: There is no statistically significant difference in finally clinical outcomes between hexapod external fixator and monolateral external fixator in the definitive treatment of high-energy tibial diaphyseal fractures. The hexapod external fixation treatment is a superior effective method, including advantages of stable fixation, less surgical duration, postoperatively satisfactory fracture reduction, and fewer complications.

[V-Y plasty combined with gastrocnemius aponeurosis turndown repairing the Myerson type â ¢ chronic Achilles tendon rupture].

Objective: To investigate the clinical application and effectiveness of V-Y plasty combined with gastrocnemius aponeurosis turndown in the repair of Myerson type Ⅲ chronic Achilles tendon rupture combined with large tendon defect. Methods: Between February 2008 and July 2019, 25 patients underwent the V-Y plasty combined with gastrocnemius aponeurosis turndown to treat the Myerson type Ⅲ chronic Achilles tendon rupture. There were 21 males and 4 females. The age ranged from 17 to 56 years, with an average of 34.3 years. Achilles tendon rupture was caused by sports injury in all patients, and the duration from Achilles tendon rupture to operation was 31-70 days, with an average of 53.9 days. After resection of fibrous scar tissue, the distance of Achilles tendon defect was 7-12 cm, with an average of 9.04 cm. The clinical results were evaluated by the Achilles tendon total rupture score (ATRS), American Orthopaedic Foot and Ankle Society (AOFAS) score, dorsiflexion and heel raise height before and after operation. Results: The donor and recipient wounds of all 25 cases healed by first intention after operation. All patients were followed up 24 months. During the follow-up, 3 patients developed mild wound infection, which was cured after anti-infection treatment. One patient had Achilles tendon exposure, which was cured after local flap transfer and repair. Ultrasound and MRI reexamination at 3-12 months after operation showed no Achilles tendon elongation, adhesion, or re-rupture. At 24 months after operation, the ATRS score, AOFAS score, dorsiflexion and heel raise height of affected side significantly improved when compared with those before operation (P<0.05). However, the dorsiflexion and heel raise height of affected side were still significantly worse than those of the healthy side (P<0.05). Conclusion: V-Y plasty combined with gastrocnemius aponeurosis turndown to repair the chronic Achilles tendon rupture can achieve good effectiveness, and the Achilles tendon function significantly improved after repair. However, the procedure is more invasive and has a long duration of intraoperative wound exposure, causing an increased risk of infection, and the aesthetic is not good.

Efficacy comparison of trifocal bone transport using unilateral external fixator for femoral and tibial bone defects caused by infection.

BACKGROUND: This study aimed to evaluate the clinical and functional outcomes of patients with femoral and tibial critical-sized bone defect (CSBD) treated by trifocal bone transport using the Ilizarov method. METHODS: From March 2011 and January 2017, clinical and radiographic data of patients with CSBD (> 6 cm) caused by infection were documented and analyzed. Patients were divided into the femur group (n = 18) and tibia groups (n = 21) according to the location of bone transport. The bone and functional outcomes were evaluated according to the Association for the Study and Application of the Method of the Ilizarov (ASAMI) criterion, and postoperative complications were evaluated by Paley classification. RESULTS: A total of 39 patients were managed by the trifocal bone transport for the femur (n = 18) or tibia (n = 21) bone defects with a mean follow-up time of 26.1 months (range 17-34 months). Eighteen femurs and 21 tibias with a mean distraction regenerate length (DRL) of 8.3 cm (range 6-13 cm) and 7.5 cm (range 6-11 cm) respectively. Infection was eradicated in all patients, and the total bone union was received in all cases (100%). Statistical difference of bone grade (excellent/good/fair/poor, 3/11/3/1 vs 2/13/4/2, P < 0.05), and function grade (excellent/good/fair/poor, 3/14/1/0 vs 4/13/3/1, P < 0.05) were respectively observed between the femur group and tibia group. The excellent and good rate of bone (femur vs tibia, 77.8% vs 71.4%), and function grade (femur vs tibia, 94.4% vs 80.9%) was higher in the femur group than the tibia. The rate of complication in the femur group was lower than in the tibia (femur vs tibia, 94.4% vs 76.2%). One femur and five tibias were performed additional surgery for delayed union and axial deviation. CONCLUSIONS: The trifocal bone transport using the unilateral external fixator was a practical method in the management of CSBD in the lower extremity. The BUT and EFI of the femur group were shorter than the tibia. Although the complications noted were more frequent on the femur, these were mostly minor.

Hypoxia During the Consolidation Phase of Distraction Osteogenesis Promotes Bone Regeneration.

Background: Hypoxia is the critical driving force for angiogenesis and can trigger the osteogenic-angiogenic coupling followed by the enhancement of bone regeneration. While lots of studies showed that hypoxia administration can accelerate bone formation during distraction osteogenesis (DO), the therapeutic timing for the osteogenic purpose was concentrated on the distraction phase. The outcomes of hypoxia administration in the consolidation phase stay uncertain. The purpose of this study was to determine the osteogenic effectiveness of hypoxia therapy during the consolidation phase, if any, to enhance bone regeneration in a rat femoral DO model. Methods: A total of 42 adult male Sprague-Dawley rats underwent right femoral mid-diaphysis transverse osteotomy and were randomly divided into Control (NS administration, n = 21) and Group1 (deferoxamine therapy, n = 21) after distraction. During the consolidation phase, Group1 was treated with local deferoxamine (DFO) injection into the distraction zone, while the Control underwent the same dosage of NS. Animals were sacrificed after 2, 4, and 6 weeks of consolidation. The process of bone formation and remodeling was monitored by digital radiographs, and the regenerated bone was evaluated by micro-computed tomography (micro-CT), biomechanical test, and histological analysis. The serum content of hypoxia-inducible factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) were measured by enzyme linked immunosorbent assay (ELISA) for further analysis. Results: Bone regeneration was significantly enhanced after hypoxia therapy during the consolidation phase. The digital radiograph, micro-CT, and biomechanical evaluation showed better effects regarding volume, continuity, and mechanical properties of the regenerated bone in Group1. The histomorphological evaluation also revealed the hypoxia treatment contributed to accelerate bone formation and remodeling during DO. The higher positive expression of angiogenic and osteogenic markers were observed in Group1 after hypoxia administration according to the immunohistochemical analysis. The serum content of HIF-1α and VEGF was also increased after hypoxia therapy as evidenced from ELISA. Conclusion: Hypoxia administration during the consolidation phase of distraction osteogenesis has benefits in enhancing bone regeneration, including accelerates the bone formation and remodeling.

Staged correction trajectory with hexapod external fixator for the satisfactory reduction of long bone shaft fracture.

BACKGROUD: When the reduction of long bone shaft fracture fragments is performed by a hexapod external fixator, the collision and interference between bony ends often results in an incomplete reduction and a time-consuming procedure. The purpose of this study was to present and determine the clinical effectiveness of staged correction trajectory with hexapod external fixator in the reduction of a long bone shaft fracture. METHODS: A total of 57 patients with tibial shaft fractures treated by hexapod external fixator were retrospectively analyzed from June 2016 to February 2020. Thirty-one cases (Group I) underwent a conventional one-step reduction trajectory from June 2016 to July 2018. Starting in September 2018, the other twenty-six patients (Group II) underwent staged correction trajectory (three key points reduction trajectory of "distraction-derotation-reduction"). The demographic data, residual deformities before and after correction, number of repeated X-rays after the first postoperative X-ray, duration of deformity correction process, and external fixation time were analyzed. Johner-Wruhs criteria were used to evaluate the final clinical outcomes. RESULTS: All the 57 patients achieved satisfactory fracture reduction and bone union. There were no significant differences between the two groups in demographic data, residual deformities before and after correction, external fixation time, and final clinical outcomes (p > 0.05). The average number of repeated X-rays after the first postoperative X-ray and mean duration of deformity correction process in Group II (1.3 times, 2.9 days) were all less than those in Group I (2.3 times, 5.1 days) (p < 0.05). CONCLUSION: Compared with the conventional one-step reduction trajectory, there is no differences in final clinical outcomes, but the staged correction trajectory provides less repeated X-rays and shorter reduction process duration.

Improving postoperative radiographs for the parameter measurement of hexapod external fixator using an additional foot ring.

BACKGROUND: It is challenging to determine the orthogonality of radiographs in daily clinical practice. The purpose of this study was to show the usefulness of an additional foot ring which might determine the orthogonality of postoperative radiographs for the parameter measurement of hexapod external fixator. METHODS: We retrospectively analyzed 81 consecutive trauma patients with tibial shaft fractures treated by the hexapod external fixator at our institution from September 2014 to July 2019. Starting in March 2016, the postoperative radiographs for parameter measurement were obtained under the control of an additional foot ring. The final data consisted of 47 patients in traditional radiographs (Group I) and 34 patients under the control of foot ring during the radiographic process (Group II). The demographic data, original postoperative deformities, residual deformities after final correction, number of repeated radiographs after the first postoperative radiographs, time to the satisfactory reduction achieved, and external fixation time in all patients were documented and analyzed. The Johner-Wruhs criteria were used for the final clinical outcomes evaluation at the last clinical visit. RESULTS: Satisfactory reduction and bone union were achieved in all patients. There were no statistical significances between the two groups in the demographic data, original postoperative deformities, residual deformities after final correction, external fixation time, and the final clinical outcomes (P > 0.05). The mean number of repeated radiographs after the first radiographs (1.4 times) and mean time to the satisfactory reduction achieved (3.3 days) in patients with an additional foot ring used were all less than those without foot ring (2.4 times, 5.3 days) (P < 0.05). CONCLUSIONS: The additional foot ring is a practical device to ensure the orthogonality of postoperative radiographs for the hexapod external fixator parameter measurement. Radiation exposure, duration of deformity correction, and cost for patients might be reduced due to the less repeated radiographs with the wrong position.

Risk factors of pin tract infection during bone transport using unilateral external fixator in the treatment of bone defects.

BACKGROUND: The bone transport using the unilateral external fixator, one of the Ilizarov techniques, is widely practiced in lower limb reconstructive surgery. Pin tract infection (PTI), one of most common complication, has become the important postoperative problems which plague clinicians gradually. METHODS: A group of 130 patients who received bone transport surgery for tibia or femur defects using the unilateral external fixation (Orthofix limb reconstruction system, Verona, Italy) and met the inclusion criteria were selected for the study from 2015 to 2019. Regular pin tract care was performed twice a day, and the conditions of the pin tract were evaluated by the same observer using clinical appearance criteria. The Saw's classification of PTI was used to assess the condition around screws. After the data were significant by the T-test or Pearson's Chi-square test analyzed, odds ratios were calculated using logistic regression tests to describe factors associated with the diagnosis of PTI. RESULTS: Ninety-one males and thirty-nine females with a mean age of 43 years (range 28-58 years) were included in this cohort. 7816 observations were documented from 12 to 36 months, and 58 cases (44.6%) of PTI (thirty-nine cases in grade 1, 17 cases in grade 2, and 2 cases in grade 3). The top five risk factors were agricultural work (OR 1.86, CI 0.94-2.39), non-urban living (OR 1.75, CI 1.24-3.26), male (OR 1.71, CI 1.02-2.31), smoking (OR 1.53, CI 0.76-1.89), and diabetes (OR 1.26, CI 1.12-2.64). No long-term sequelae were observed at the latest clinical visit. CONCLUSION: Occupation, gender, living environment (non-urban), smoking, and diabetes were the top five significant risk factors for PTI in the period of bone transport using unilateral external fixation. Awareness of predictable risk factors of PTI is beneficial to avoid or early detect the severe complications which can affect the effectiveness.

Intraoperative acute correction versus postoperative gradual correction for tibial shaft fractures with multiplanar posttraumatic deformities using the hexapod external fixator.

BACKGROUND: The purpose of this study was to determine the differences in clinical outcomes, if any, between intraoperative acute correction and postoperative gradual correction for tibial shaft fractures with multiplanar posttraumatic deformities using the hexapod external fixator. METHODS: We retrospectively analyzed 58 consecutive patients with tibial shaft fractures treated by the hexapod external fixator at our institution from January 2015 to April 2019. Twenty-three patients (Group I) underwent intraoperative acute correction, from January 2015 to October 2016. Starting in November 2016, the other 35 patients (Group II) all underwent postoperative gradual correction. The demographic data, operation duration, original residual deformities before correction, residual deformities after correction, and external fixation time were collected and analyzed. The clinical outcomes were evaluated by the Johner-Wruhs criteria at the last clinical visit. RESULTS: All patients achieved complete bone union with a mean time of 28.7 ± 4.6 weeks (range 21 to 37 weeks) in Group I and 27.9 ± 4.8 weeks (range 19 to 38 weeks) in Group II (P > 0.05). The operation duration in Group I (88.9 ± 7.7 min) was longer than that in Group II (61.9 ± 8.4 min), and there was a statistically significant difference (P < 0.05). There were no statistically significant differences between the two groups in original residual deformities before correction and residual deformities after correction (P > 0.05). The rate of postoperative complication was similar between the two groups. There was no statistical significance in demographic data and clinical outcomes between the two groups (P > 0.05). CONCLUSIONS: There is no difference in clinical outcomes between intraoperative acute correction and postoperative gradual correction for tibial shaft fractures with multiplanar posttraumatic deformities using the hexapod external fixator. Postoperative gradual correction may shorten the duration in the operation room and decrease the potential intraoperative risk.

[Effectiveness of free anterolateral thigh flap in repairing hand twist trauma combined with forearm main vascular injury].

OBJECTIVE: To evaluate the effectiveness of free anterolateral thigh flap in repairing hand twist trauma combined with forearm main vascular injury. METHODS: Between February 2016 and March 2020, 14 patients with hand twist trauma combined with forearm main vascular injury were admitted. There were 10 males and 4 females. The mean age was 36.3 years (range, 22-53 years). There were 5 cases with left hand and 9 cases with right hand. The degloving injury of hand was rated as type ⅢA in 2 cases, type ⅢB in 9 cases, and type Ⅳ in 3 cases. The size of soft tissue defects range from 8.0 cm×4.5 cm to 13.5 cm×8.0 cm. Of all patients, 11 cases were ulnar artery injury and 3 cases were radial artery injury. Time from injury to operation was 2-16 hours (mean, 7.1 hours). The free anterolateral thigh flaps with the size of 10.0 cm×5.5 cm to 15.0 cm×9.5 cm were used to repair the soft tissue defects with the "T" shape anastomosis of blood vessel in 8 cases or direct anastomosis of blood vessel in 6 cases. The donor sites were directly sutured in 9 cases and repaired with free skin graft in 5 cases. RESULTS: All patients were followed up 6-12 months (mean, 10.5 months). The vascular crisis occurred in 1 case and the flap survived with symptomatic treatment after operation. Other flaps survived and the wounds healed by first intention. All donor sites healed by first intention and the skin grafts survived. Three cases underwent the fat-free trimming at 4-5 months after operation. According to the evaluation standard of the upper limb part of the Chinese Medical Association, the hand function was evaluated as excellent in 4 cases, good in 7 cases, and fair in 3 cases, with an excellent and good rate of 78.6% at last follow-up. CONCLUSION: Because the diameter of the descending branch of the lateral femoral circumflex artery is similar to that of the ulnar artery and radial artery, the use of free anterolateral thigh flap can not only repair the wound and obtain a good hand shape, but also repair blood vessels and promote recovery of hand function.

The efficiency of internal fixation with bone grafting at docking sites after bone transport for treatment of large segmental tibial bone defects.

OBJECTIVE: To investigate the efficiency of internal fixation with bone grafting after bone transport for treatment in large-segment bone defects of the lower-limbs. METHODS: This prospective study recruited 100 patients with lower limb tibial segmental bone defects, and based on a random number table they were divided into a control group (n=50, simple bone transport surgery) or an observation group (n=50, internal fixation with bone grafting at docking site after bone transport). The fracture healing time, bone healing index, external fixation time in both groups were compared. The knee function, joint range of motion, and the function of the ankle and hindfoot before and after surgery were also analyzed and compared between the two groups respectively, as well as the rate of complications in both groups was calculated. RESULTS: Compared with the preoperative condition of patients, the Lysholm knee scale, ROM score, and AHS scores of patients in the two groups were significantly increased 10 months after surgery, moreover, those scores of the observation group were higher than that of the control group (P<0.05). The fracture healing time and external fixation time of patients were significantly declined in the observation group when compared to the control group, additionally, the bone healing index was also reduced significantly (P<0.05). When compared with patients in the control group, the ratios of bone healing and lower-limb functional recovery of patients in the observation group were significantly higher while the total complication incidence was decreased remarkably (P<0.05). CONCLUSION: Internal fixation with bone grafting after bone transport can promote fracture healing, improve joint function, and reduce complications during treatment for a large segmental bone defects in the lower limbs.

Bony callus stiffness indirectly evaluated by the axial load-share ratio in vivo as a guide to removing a monolateral external fixator safely.

PURPOSE: As the monolateral external fixator is increasingly used in trauma-control and definitive management for high-energy long bone fractures, timing the fixator removal remains a challenge for surgeons. The purpose of this study was to determine the feasibility and effectiveness of the bony callus stiffness indirectly evaluated by the axial load-share ratio in vivo as a guide to removing a monolateral external fixator safely. METHODS: A total of 131 patients with tibial shaft fractures treated by the monolateral external fixator in our institution were collected from January 2013 to July 2019. In group I, the fixators were removed based on the clinical and radiological assessment only by the treating surgeon. As for group II, the axial load-share (LS) ratio test was accomplished by another medical team without the knowledge of the clinical results. The external fixator was removed when the mechanical test outcome (LS ratio < 10%) was consistent with the conclusion drawn from the clinical and radiological assessment (bone union achieved) by the treating surgeon. RESULTS: There was no statistical significance in demographic data between the two groups (P > 0.05). In group I, four patients suffered refracture (the refracture rate was 7.7%) after fixator removal and were successfully treated by an intramedullary nail. In group II, 71 patients underwent fixator removal after the first mechanical test, and another eight patients terminated the external fixation after the second test. None of the 79 patients in group II suffered refracture (the refracture rate was 0%). There was statistical significance in the refracture rate between the two groups (P < 0.05). CONCLUSION: The bony callus stiffness indirectly evaluated by the axial load-share ratio in vivo using the additional circular frame components is an effectively quantitative indicator to complement the clinical assessment of fracture healing in a monolateral external fixation treatment. Removal of the monolateral external fixator is safe when the axial load-share ratio dropped below 10%.

Risk factors of ankle osteoarthritis in the treatment of critical bone defects using ilizarov technique.

BACKGROUND: Distraction osteogenesis using the Ilizarov external circular fixator has been applied in lower limb reconstructive surgery widely. The increasing ankle osteoarthritis (OA) progression and severity are often associated with the period of external fixator and the greater relative instability of the ankle joint, but few studies have quantified risk factors directly during this technique. METHODS: The study was conducted on 236 patients who underwent bone transport surgery for tibias using the Ilizarov external circular fixator from 2008 to 2018. The cumulative incidence of ankle OA diagnoses in patients after the Ilizarov technique treatment was calculated and stratified by risk factors from preoperative and postoperative management. After the data were significant through the Mann-Whitney U test analyzed, odds ratios were calculated using logistic regression to describe factors associated with the OA diagnosis including gender, age, BMI, location of bone defect, diabetes, hypertension, osteoporosis, the history of metal allergy and glucocorticoid intake, the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-HF scale scores, defect size (DS), the type of bone transport, the bone union time, external fixator time (EFT), and external fixator index (EFI). RESULTS: There were 199 males and 37 females with a mean age of 47 years (range 28-59 years). Out of 236 patients, 49 had an additional treatment for ankle OA after the Ilizarov technique treatment of bone defects (average follow-up time 2.1 years, range 1.6-4.2 years). The incidence of postoperative ankle OA was 20.8 %, with 19 patients classified as K&L grade 3 and seven patients as grade 4. The top five risk factors included double-level bone transport (OR3.79, P = 0.005), EFI > 50days/cm (OR3.17, P = 0.015), age > 45years (OR2.29, P = 0.032), osteoporosis (OR1.58, P < 0.001), BMI > 25 (OR1.34, P < 0.001). Male, BMI > 25, diabetes, osteoporosis, and AOFAS ankle-HF scale scores are the independent risk factors. CONCLUSIONS: Ilizarov external circular fixator is a safe and effective method of treatment for critical bone defects. The double level bone transport, EFI > 50days/cm, age > 45years, osteoporosis, BMI > 25 are the top five relevant risk factors of ankle OA. The probability of developing ankle OA among patients having three or more risk factors is 50-70 %.

Cyclic Distraction-Compression Dynamization Technique Enhances the Bone Formation During Distraction Osteogenesis.

Background: Interfragmentary movements have benefits in the improvement of bone formation during distraction osteogenesis (DO). Although several clinical studies reported positive outcomes regarding the application of the cyclic distraction-compression (CDC) dynamization technique in cases with poor bone formation during DO, they are mostly anecdotal without a detailed description. The purpose of this study was to investigate the effectiveness and potential mechanism of different amplitudes and rates of the CDC technique on bone regeneration in a rat femur DO model. Methods: A total of 60 adult male Sprague-Dawley rats underwent right femoral mid-diaphysis transverse osteotomy and were randomly and evenly divided into Control (no manipulation), Group1 (CDC therapy), Group2 (CDC therapy with larger amplitude), and Group3 (CDC therapy with a slower rate) after distraction. The CDC technique was performed during the middle phase of the consolidation period according to different protocols. Animals were sacrificed after 4 and 6 weeks of consolidation. The process of bone formation was monitored by digital radiographs, and the regenerate bone was evaluated by micro-computed tomography (micro-CT), biomechanical test, and histological analysis. The serum contents of hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) were measured by enzyme-linked immunosorbent assay (ELISA). Results: Bone regeneration after the CDC technique was improved significantly during DO. The digital radiograph, micro-CT, histomorphological analysis, and biomechanical evaluation showed better effects regarding volume, continuity, and mechanical properties of the regenerate bone in Group2 and Group3 when compared to Group1. The angiogenic and osteogenic markers were more highly expressed in Group2 and Group3 than in Group1 according to the immunohistochemical analysis. As for ELISA, the serum contents of HIF-1α and VEGF were also increased after the CDC technique, especially in Group2 and Group3. Conclusion: The CDC dynamization technique has benefits on the improvement of bone formation during DO, and the mechanism may be due to tissue hypoxia activating the HIF pathway followed by the augmentation of osteogenic-angiogenic coupling. Better outcomes may be achieved by moderately increasing the amplitude and slowing down the rate of the CDC technique.