A review of 10 patients treated with the masquelet technique and microsurgical technique combined for Gustilo type III open tibial fractures.

BACKGROUND: Open tibial fractures often include severe bone loss and soft tissue defects and requires complex reconstructive operations. However, the optimal treatment is unclear. METHODS: This retrospective study enrolled patients with Gustilo type III open tibial fractures from January 2018 to January 2021 to assess the clinical utility of Masquelet technique together with microsurgical technique as a combined strategy for the treatment of open tibial fractures. The demographics and clinical outcomes including bone union time, infection, nonunion and other complications were recorded for analysis. The bone recovery quality was evaluated by the AOFAS Ankle-Hindfoot Scale score and the Paley criteria. RESULTS: We enrolled 10 patients, the mean age of the patients and length of bone defects were 31.7 years (range, 23-45 years) and 7.5 cm (range, 4.5-10 cm) respectively. Bone union was achieved for all patients, with an average healing time of 12.2 months (range, 11-16 months). Seven patients exhibited a bone healing time of less than 12 months, whereas 3 patients exhibited a bone healing time exceeding 12 months. No significant correlation was found between the length of bone loss and healing time. In addition, no deep infection or nonunion was observed, although 2 patients experienced wound fat liquefaction with exudates and 1 patient presented with a bloated skin flap. The average AOFAS Ankle-Hindfoot Scale score was 80.5 (range, 74-85), and all patients were evaluated as good or exellent based on the Paley criteria. CONCLUSIONS: Our study indicated that the use of the Masquelet technique and the microsurgical technique as a combined strategy is safe and effective for the treatment of Gustilo type III open tibial fractures.

"Sandwich" Structure in Reconstruction of Traumatic Comminuted Anterior Skull Base Fractures: Surgical Technique and Outcomes.

BACKGROUND: Comminuted fractures of the anterior skull base can easily cause dural damage, leading to cerebrospinal fluid leakage and retrograde infection. Skull base reconstruction is essential. This study aimed to present a novel and simple technique for repairing skull base defects using a self-made fascia-bone fragments-fascia "sandwich" structure made by fascia, fracture fragments, and sutures. METHOD: From 2018 to 2023, we performed self-made sandwich structures for skull reconstruction in 10 patients with anterior skull base comminuted fractures. After debridement, the intracranial bone fragments of the surgical patient were safely removed. In vitro, the bone fragments were spread between two layers of temporal or broad fascia to form a sandwich structure similar to the size of the bone defect, and the periphery was firmly sutured with sutures. The self-made structure was then filled to the defect and fixed with fibrin glue. The periosteum at the top of the forehead was also turned over to the repair area for covering and fixation. Meanwhile, a facial skin cosmetic suture was performed. Finally, we evaluate the feasibility and efficacy of this technique. RESULTS: All 10 patients underwent reconstructive surgery using the self-made fascia-fracture fragments-fascia sandwich structure. Five patients with open wounds on the face also underwent cosmetic revisions. No cerebrospinal fluid leakage occurred in all the patients at discharge as well as 3 months later. CONCLUSIONS: For patients with comminuted fracture of the anterior skull base, the fascia-bone fragments-fascia structure could repair the skull base and prevent the occurrence of cerebrospinal fluid leakage.

Treatment of Unfixable Inferior Pole Fractures of the Patella Using an All-Suture Internal Fixation Technique.

Inferior pole fractures of the patella are a type of patellar fracture that has various complexities. Most current techniques are associated with hardware-related complications, which is one of the main concerns when treating this complex fracture. We present a new technique that does not require metal implant removal, causes little to no irritation of the quadriceps muscle, and provides strong fixation that allows for early range of motion postoperatively.

Overcoming the Dilemma of In Vivo Stable Adhesion and Sustained Degradation by the Molecular Design of Polyurethane Adhesives for Bone Fracture Repair.

Bone adhesive is a promising candidate to revolutionize the clinical treatment of bone repairs. However, several drawbacks have limited its further clinical application, such as unreliable wet adhesive performance leading to fixation failure and poor biodegradability inhibiting bone tissue growth. By incorporating catechol groups and disulfide bonds into polyurethane (PU) molecules, an injectable and porous PU adhesive is developed with both superior wet adhesion and biodegradability to facilitate the reduction and fixation of comminuted fractures and the subsequent regeneration of bone tissue. The bone adhesive can be cured within a reasonable time acceptable to a surgeon, and then the wet bone adhesive strength is near 1.30 MPa in 1 h. Finally, the wet adhesive strength to the cortical bone will achieve about 1.70 MPa, which is also five times more than nonresorbable poly(methyl methacrylate) bone cement. Besides, the cell culture experiments also indicate that the adhesives show excellent biocompatibility and osteogenic ability in vitro. Especially, it can degrade in vivo gradually and promote fracture healing in the rabbit iliac fracture model. These results demonstrate that this ingenious bone adhesive exhibits great potential in the treatment of comminuted fractures, providing fresh insights into the development of clinically applicable bone adhesives.

Adjunctive intraosseous wiring fixation technique for the comminuted distal humeral fractures.

Distal humeral fractures are among the most challenging injuries to treat. Although precise repair of the articular surface is essential during surgery, accurate reconstruction of the metaphysis contributes to the overall stability of the fracture construct. The intraosseous wiring technique has been used for small-fragment fractures. However, its efficacy as an adjunct for distal humerus fixation has yet to be thoroughly investigated. This study aimed to demonstrate the applicability of this technique to comminuted, distal humeral fractures. In this retrospective case series, we describe 6 cases of intra-articular distal humerus fractures treated with this technique, followed by dual plating. We observed successful bone union in all patients, with the Mayo Elbow Performance Scores indicating "good" to "excellent" clinical outcomes for this procedure at the final follow-up. We believe that this intraosseous wiring technique should be an integral part of the toolbox of every surgeon because it is a relatively simple and highly effective procedure that requires no special instrument and can be used on various types of fractures.

Development and characterization of an intra-articular fracture mediated model of post-traumatic osteoarthritis.

PURPOSE: This study aimed to develop and characterize a closed intra-articular fracture (IAF) mediated post-traumatic osteoarthritis (PTOA) model in rats to serve as a testbed for putative disease modifying interventions. METHODS: Male rats were subject to a 0 Joule (J), 1 J, 3 J, or 5 J blunt-force impact to the lateral aspect of the knee and allowed to heal for 14 and 56 days. Micro-CT was performed at time of injury and at the specified endpoints to assess bone morphometry and bone mineral density measurements. Cytokines and osteochondral degradation markers were assayed from serum and synovial fluid via immunoassays. Histopathological analyses were performed on decalcified tissues and assessed for evidence of osteochondral degradation. RESULTS: High-energy (5 J) blunt impacts consistently induced IAF to the proximal tibia, distal femur, or both while lower energy (1 J and 3 J) impacts did not. CCL2 was found to be elevated in the synovial fluid of rats with IAF at both 14- and 56-days post-injury while COMP and NTX-1 were upregulated chronically relative to sham controls. Histological analysis showed increased immune cell infiltration, increased osteoclasts and osteochondral degradation with IAF relative to sham. CONCLUSION: Based on results from the current study, our data indicates that a 5 J blunt-forced impact adequately and consistently induces hallmark osteoarthritic changes to the articular surface and subchondral bone at 56 days after IAF. Marked development of PTOA pathobiology suggest this model will provide a robust testbed for screening putative disease modifying interventions that might be translated to the clinic for militarily relevant, high-energy joint injuries.

Management of Comminuted Fracture of Mandible Using Titanium Mesh.

Comminuted mandibular fractures are common following a high-velocity injury to the face and jaws. The inherent nature of injury and damage to the underlying hard and soft tissues often complicate the management of comminuted fractures. Traditionally, comminuted fractures were managed by closed reduction and external skeletal fixation. Titanium mesh serves as an excellent alternative in the management of comminuted mandibular fractures. The present case report presents the successful management of comminuted mandibular fractures using titanium mesh.

Clinical Results of Distal Radius Intraarticular Comminuted Fractures in the Elderly: A Retrospective Comparative Analysis of Different Fixation Methods.

Introduction Distal radius intraarticular fractures in the elderly population are likely to cause impaired clinical outcomes. Intraarticular fracture treatment in the literature is a debatable issue with mixed results. Here, we aimed to present a tertiary trauma center experience with plate fixation and K wire-assisted external fixator in elderlies over 60 years old. Material and methods Patients who were diagnosed with an unstable intraarticular distal radius fracture and received surgical treatment with plate fixation or K wire-assisted external fixator between 2016 January and 2020 January were included in the study. Patients were evaluated retrospectively in terms of radiologic stability criteria and clinical outcomes. Results There were 27 patients; 14 in the volar plate group (group 1) and 13 (group 2) in the external fixator group. The mean age was 64.2 (60-72) in group 1 and 67.7 (60-76) in group 2. The mean follow-up time was 31.6 (12-63) in group 1 and 28.8 (12-59) in group 2. The mean quick disabilities of the arm, shoulder, and hand (Q-DASH) score was 25.7 (5-75) in group 1 and 24.4 (10-87) in group 2. The mean patient-reported wrist evaluation (PRWE) was 27.1 (6-87) in group 1 and 31.4 (10-87) in group 2. There was no statistical difference between groups in terms of clinical scores, hospital stay, follow-up, and complications. (p>0.05). Conclusion Although open reduction and plate fixation and K wire-assisted external fixator are viable options for providing radiologic union, unsatisfactory clinical outcomes were maintained independently of the fixation method in elderly patients.

Dorsal bridge plating versus bridging external fixation for management of complex distal radius fractures.

INTRODUCTION: Distal radius fractures are the most frequent upper limb injuries encountered by orthopedic surgeons. Surgical treatment of distal radius fractures is preserved for unstable and displaced fractures. A randomized controlled trial was conducted to compare the radiological and functional outcomes of bridge plating (BP) to external fixation (EF) in comminuted intra-articular distal radius fractures. METHODS: Sixty patients with distal radius fractures were eligible for treatment by means of ligamentotaxis using either a dorsal bridge plate (30 patients) or an external fixator (30 patients) with or without supplementary Kirschner wires (K-wires). Radiological evaluation was done using the radial inclination angle, radial length, and the volar tilt. Clinical evaluation was performed using ranges of wrist motion, grip strength, Visual Analogue Scale (VAS), and a validated Arabic version of the Disability of the Arm, Shoulder, and Hand (DASH) questionnaire RESULTS: Patients were followed up for 12 months. No significant difference was found in terms of radiographic parameters or ranges of wrist motion. At 3-months follow-up, bridge plating group had stronger grip strength, lower Disability of the Arm, Shoulder, and Hand scores, and lower Visual Analogue Scale. However, both groups had similar functional outcomes at last follow-up. External fixation group had a higher rate of postoperative complications. CONCLUSION: In comparison to external fixation, bridge plating may provide earlier functional recovery with lower complication rates. However, no functional or radiological superiority were demonstrated at 12-months follow-up.

Seemingly inconsequential yet catastrophic: the importance of wound washout with minute depressed skull fracture from a dog bite.

Depressed skull fractures from dog bites are common pediatric head injuries which are contaminated with native skin and canine oral flora. Outcomes can potentially be catastrophic. Thus, these injuries require proper initial management to prevent future complications. We present an 18-month-old female who was bitten by a Great Dane dog and resulted in a small left temporal depressed skull fracture with an underlying brain contusion. This was initially treated conservatively with antibiotics and bedside irrigation. Five weeks later, she developed a large multiloculated abscess with mass effect, which required surgical aspiration and wound debridement. After long-term antibiotics, she made a full neurologic recovery. Our case illustrates the importance of washing out a seemingly inconsequential depressed skull fracture from a dog bite to avoid development of a cerebral abscess.

Functional and radiological outcomes following plating for displaced fractures of patella: A pilot study.

INTRODUCTION: Patellar fractures constitute almost 1% of total skeletal injuries. Existing common operative methods include the use of different types of Tension band wiring techniques like cannulated screws and K-wires. The Patellar plating construct is a relatively newer operative method for patellar fracture fixation with promising outcomes with fewer complications. METHOD: We conducted a pilot prospective study at our Apex Trauma center in twenty patients aged 18-65years with displaced patellar fractures, AO type A2, A3, B2, B3, C1, C2, C3. Fractures were fixed with low profile patellar plates (1.8 mm). Radiological and functional follow-up was done using X-rays, CT scans and BKS scoring (Bostman-Knee-Scale), Knee Society Score(KSS), and Tegner Lysholm knee scores respectively for two years. RESULT: Mean functional outcome scores at 6 weeks, 3 months, 6 months and 2 years was 25.5, 28.3, 29.05 and 29.9 for BKS; 64.62, 84.12, 90.6, and 97.5 for KSS; 73.75, 89.7,94.8, and 99.3 for Tegner Lysholm knee score respectively. Radiological union, confirmed by CT scan, was observed in all patients at 3 months. Two patients had superficial surgical site infection (SSI) at 2 weeks. Implant impingement was also found in 2 patients at 3 months. None of the patients had a failure of fixation at the end of the study. CONCLUSION: Patients with low profile patellar plate constructs have favorable clinical and radiological outcomes with minimal non-specific complications.

The effect of post-fixation olecranon lengthening on range of motion of the elbow: a cadaveric study.

BACKGROUND: Principles of fixation of comminuted olecranon fractures include anatomical reduction of the articular surface and restoration of ulnohumeral joint motion. However, comminution sometimes may not permit anatomical fixation of fracture fragments, resulting in inadvertent olecranon lengthening after plate fixation. The aim of our study is to investigate the relationship between olecranon lengthening following plate fixation and loss of elbow extension. MATERIALS AND METHODS: Transverse olecranon osteotomies were performed on 8 cadaveric elbows. The osteotomy sites were then fixed with olecranon plates. Lengthening of the osteotomy sites were simulated by placement of 2mm, 4mm, 6mm and 8mm blocks. Lateral view photographs of the elbows were taken after each degree of lengthening. These photographs were then printed and measurements of elbow extension were performed with a goniometer with average values taken. The measurements were tabulated and statistical analysis performed to determine the relationship between degree of elbow extension loss and amount of olecranon lengthening. RESULTS: Average values of each degree of lengthening (at 2mm, 4mm, 6mm and 8mm) were taken and compared with the baseline measurement (at 0mm). Cluster analysis showed that for every increment in osteotomy length of 2mm, there is a corresponding increase of 0.79° of elbow extension loss (p<0.01, 95% confidence level 0.55°-1.03°). CONCLUSION: Lengthening of olecranon by increments of 2mm correlates positively with loss of elbow extension. This shows that inadvertent intra-operative olecranon lengthening post-fixation may result in limited range of motion. However, it is reassuring to know that the small degree of extension loss may not translate to functional limitation.

Comparison of total patellectomy and osteosynthesis with tension band wiring in patients with highly comminuted patella fractures: a 10-20-year follow-up study.

BACKGROUND: The purpose of this study was to evaluate and compare the long-term clinical outcomes between the total patellectomy and osteosynthesis with tension band wiring in patients with highly comminuted patella fractures. METHODS: Between January 1987 and December 2003, this retrospective study included a total of 35 patients (mean age, 51.4±16.8 years) with a minimum of 10 years follow-up period, comprising 29 males and 6 females, who were divided into the total patellectomy group (17 patients) or the open reduction and internal fixation (ORIF) group (18 patients) in the Third Affiliated Hospital of Hebei Medical University. We retrospectively collected patient demographics and data on the type of trauma, fracture type, and postoperative complications. Clinical outcomes including knee range of motion (ROM), 36-Item Short-Form Health Survey (SF-36) score [including physical component score (PCS) and mental component score (MCS)], Knee Injury and Osteoarthritis Outcome Score (KOOS), and Kujala score were evaluated and compared between the two groups. Biodex System dynamometer was used to quantitatively evaluate quadriceps femoris muscle power following measurement of peak torque. RESULTS: The mean follow-up periods of the total patellectomy group and the ORIF group were 17.2±5.6 and 16.8±4.9 years, respectively. There were no significant differences between the two groups of patient demographics in terms of the number of patients, age, sex, injury side, time to surgery, type of trauma, and fracture classification (p>0.05). Total patellectomy was comparable to osteosynthesis with tension band wiring in terms of ROM [injured knee: 120.4±3.1° vs 118.6±3.3°; uninjured knee: 126.5±2.8° vs 127.3±1.7°; both p>0.05], peak torque [Injured knee: 96.2±2.3 vs 97.3±2.6, N· m; Uninjured knee: 107.6±2.1 vs 106.3±1.8, N· m; both p>0.05], SF-36 score [PCS: 64.1±18.0 vs 61.5±17.9; MCS: 55.1±13.8 vs 54.3±12.4; both p>0.05], KOOS score [76.3±12.1 vs 73.4±11.7; p>0.05], and Kujala score [67.6±11.8 vs 70.8±11.9; p>0.05] at the final follow-up, while total patellectomy had significantly shorter operation time than ORIF group (47.5±12.1 vs 68.8±22.3, min, p<0.05). In the total patellectomy group, complications occurred in 6 of 17 cases (35.3%), and all occurred with calcification. In the ORIF group, complications occurred in 12 of 18 cases (66.7%), including 2 cases of infection (11.1%), 1 case of non-union (5.6%), 2 cases of implant failure (11.1%), 2 cases of soft tissue irritation (11.1%), and 5 cases of patellofemoral arthritis (27.8%). CONCLUSIONS: Total patellectomy technique was a safe and reliable alternative treatment for treating patients with highly comminuted patella fractures when anatomically reduction and rigid fixation were difficult, although it caused relatively higher rates of calcification.

New Linked-Wire-Type External Fixator (the Ichi-Fixator System) for Metacarpal Fractures: Case Series and Literature Review.

Background: External fixator is an effective treatment option in the comminuted or unstable metacarpal fractures. The new linked-wire type of external fixator (the Ichi-Fixator System) developed for hand and wrist fractures enables fine adjustment of the fixation under fluoroscopic inspection through small screws inside the fixator fitted externally. This technique is designed to reinforce the stability and rigidity of conventional percutaneous Kirchner wire fixation. The aim of this study is to assess the effectiveness of the fixator for comminuted or unstable metacarpal fractures through the evaluation of short-term results in ten cases. Methods: Patients were fixated with fixator pins and metal clamps using the Ichi-Fixator System. All patients were then examined for post-operative complications, functional recovery, visual analogue scale (VAS) score, and the Quick Disabilities of the Arm, Shoulder, and Hand (Q-DASH) score at the end of the final follow-up consultation. Results: Operative treatment using the Ichi-Fixator System facilitates anatomical reduction and allows immediate full mobilization, producing good outcomes. No infections were observed in all cases, including those at pin insertion sites. There were no implant failure and nonunion. Patients could perform all routine activities with normal grip strength and retained a full range of hand motion without pain. This treatment method with improved postoperative comfort would allow immediate return to work, which would clearly boost patient satisfaction. Conclusions: Ichi-Fixator System is considered to be useful for the treatment of metacarpal fractures, and this will provide a new surgical option for all hand fractures.

The Cambridge Experience With Tibial Plateau Fractures in Older Adults: A Case Series.

Complex tibial plateau fractures (TPFs) represent a significant treatment challenge for any Orthopaedic surgeon. Current literature suggests that significantly displaced TPFs in the elderly require operative fixation, an operation that is associated with serious complications including septic and post-operative arthritis. As a result, these patients are five times more likely to require a total knee replacement (TKR). We present a case series of five elderly patients with complex TPFs who made serendipitous recoveries while awaiting operations. Their fractures were deemed so severe that they were being considered for TKR instead of fixation. We discovered their surprising functional improvements while they were being reviewed pre-operatively and decided to delay operating. We are currently unaware of any cases in the literature that have reported such findings. In total, five patients presented in 2019 with closed, varus/valgus stable fractures. They were managed non-operatively in hinged-knee braces, progressively weight-bearing with a minimum follow-up of 10 months. Oxford Knee Scores (OKS) were recorded at zero and four months after their injury. All patients were female with an average age of 69 years. Average fracture depression - 8.48mm, average fracture split - 8.66mm, average OKS reduction - 19%. All patients were able to mobilise independently at four months follow-up. Our results suggest that non-operative management can be considered as primary management in elderly patients with significantly displaced TPFs. Should this fail, or they develop arthritis, a TKR can be performed. This carries two benefits: the patient avoids the significant complications associated with fixation and should a TKR be required, it can more easily be performed in a patient without metalwork in-situ. We feel that the results from this case series might offer insight into a new treatment strategy and continue to closely follow these patients.

[Elastic, stable intramedullary nailing of pertrochanteric femoral fractures in children (<6-8 years)]. / Elastisch-stabile intramedulläre Nagelung pertrochantärer Femurfrakturen im Kleinkindesalter (<6 bis 8 Jahre).

OBJECTIVE: Minimally invasive, sufficiently stable for movement and partial weight bearing, osteosythesis of pertrochanteric femoral fractures in children < 6-8 years using elastic, stable intramedullary nailing (ESIN). INDICATIONS: Proximal, pertrochanteric femoral fractures Delbet type IV in children < 6 years. CONTRAINDICATIONS: Comminuted fractures, femoral neck fractures. SURGICAL TECHNIQUE: By inserting three elastic titanium nails (TEN), prebent in the proximal third, retrograde into the femur, a stable 3­point support stabilizes the proximal fragment. For further improvement of stability, EndCaps can be used. POSTOPERATIVE MANAGEMENT: Partial weight bearing (sole-contact) for 4-5 weeks. X­ray controls immediately after surgery and after 4-5 weeks. No sports for 3 months. RESULTS: In our patient population we have good experience with this technique for very rare pertrochanteric fractures in children younger than 6-8 years. With minimally invasive access, exercise-stable administration can be achieved without a pelvic leg cast.

The application of the Nice knots as an auxiliary reduction technique in displaced comminuted patellar fractures.

PURPOSE: To evaluate intraoperative and early postoperative clinical outcomes using the Nice knot as an auxiliary reduction technique in displaced comminuted patellar fractures. METHODS: Thirty-nine patients with unilateral closed displaced comminuted patellar fractures received open reduction and internal fixation (ORIF), utilizing either Nice knot (the NK group, 24 patients) or traditional reduction (the TR group, 23 patients) techniques, were retrospectively reviewed in this study. Intra-operative surgical time and peri-operative hemoglobin were recorded. Post-operative clinical outcomes were measured using visual analgesic score, range of motion of the knee joint and the Böstman scales, and radiographic outcomes were used to evaluate fracture healing. Complications including infection, bone non-union, implant loosening, fragment displacement and painful hardware were also assessed. RESULTS: In-hospital records indicated significantly shorter surgical duration (32.6 min) in the NK group than in the TR group (63.9 min). Intraoperative blood loss was also significantly decreased in the NK group (64.7 ml) compared to the TR group (189.1 ml). Patients in the NK and TR groups were followed for mean of 12.9 months and 12.5 months respectively. The union rate was 100% (24/24) in the NK group and 91.3% (21/23) in the TR group. In the TR group, there were two non-unions, including one infected non-union. There was no difference in the visual analgesic score, the range of motion of the knee joint or the Böstman scale at last follow-up between the two groups. CONCLUSION: The sliding, self-stabilizing Nice knot was associated with reduced surgical time, decreased intraoperative blood loss, and satisfactory postoperative outcomes in the treatment of displaced patellar fractures. Future studies are needed to ensure the generalizability of these findings to additional patient populations at other institutions.

The Influence of Medial Comminution in the Treatment Choice of Radial Head Fracture.

INTRODUCTION: The aim of our retrospective study was to investigate the role of the medial side involvement in the treatment choice of radial head fractures. MATERIALS AND METHODS: We searched the databases of our institutions for the surgical procedures diagnosed as "fracture of the radial head" and for the procedures related to "prosthesis of the radial head" and "osteosynthesis of the radial head" in the period from May 2014 to October 2017. The fractures were first classified according to the Mason classification . We then allocated the patients into three study groups according to the site of the fracture, either the medial or lateral side of the radial head : Group A, with an isolated lateral fracture of the radius head; Group B1, with a medial fracture of the radius head with two medial fragments; and Group B2, with a medial fracture of the radius head with multiple medial fragments. We performed a multivariate analysis to identify statistically significant correlation between the pre-operative classifications of Mason and our study, the type of surgical procedure, and the clinical outcome. RESULTS: Mayo Elbow Performance (MEP) scores determined at the final follow-up of the study (mean 16.6 months, range 12-26 months) was excellent in 17 patients (4 in Group A, 6 in Group B1 and 7 in Group B2), and good in 12 patients (3 in Group A, 7 in Group B1, and 2 in Group B2). One patient showed a poor result in MEP score probably because of an infection and implant removal. CONCLUSION: Regarding medial fractures of the radial head, our study showed satisfactory results with a radial head prosthesis for comminuted or multifragmentary radial head fractures. For surgeons with advanced elbow fracture expertise, osteosynthesis could be attempted in a fracture pattern that involved only two medial fragments.

Novel Aptamer-Functionalized Nanoparticles Enhances Bone Defect Repair By Improving Stem Cell Recruitment.

BACKGROUND: The restoration and repair method in the clinic of delayed fracture healing and non-union after comminuted fractures are urgently needed to improve the prognosis of patients. The recruitment of endogenous stem cells has been considered a promising approach in bone defect repair. PROPOSE: The aim of this study was to generate a de novel MSCs aptamer and developed the first, feasible, economical, bio-compatible, and functional MSCs aptamer-directed nanoparticles without complex manufacture to recruit mesenchymal stem cells (MSCs) for bone defect regeneration. METHODS: Whole-cell SELEX was used to generate a de novel MSCs aptamer. Flow cytometry was applied to assess the binding specificities, affinities and sorting abilities of the aptamers. Nano-Aptamer Ball (NAB) was constructed by NHS/EDC reaction. The diameter and zeta of NAB were assessed by dynamic light scattering. CCK8 assay was utilized to evaluate whether NAB could cause non-specific cytotoxicity and induce cell proliferation. To evaluate the bone repair capacity of NAB, histomorphological staining, alizarin red and micro X-ray were used to observe the repair degree of defect in vivo. ELISA was used to detect osteopontin (OPN), osteocalcin (BGP) by, and alkaline phosphatase (ALP) in peripheral blood. RESULTS: MSCs aptamer termed as HM69 could bind with MSCs with high specificity and Kd of 9.67 nM, while has minimal cross-reactivities to other negative cells. HM69 could capture MSCs with a purity of >89%. In vitro, NAB could bind and capture MSCs effectively, whereas did not cause obvious cytotoxicity. In vivo, serum OPN, BGP, and ALP levels in the NAB group of rats were increased at both 2 and 4 weeks, indicating the repair and osteogenesis generation. The healing of bone defects in the NAB group was significantly better than control groups, the defects became blurred, and local trabecular bone growth could be observed in X-ray. The organized hematoma and cell growth in the bone marrow of the NAB group were more vigorous in bone sections staining. CONCLUSION: These suggested that HM69 and HM69-functionalized nanoparticles NAB exhibited the ability to recruit MSCs both in vitro and in vivo and achieved a better outcome of bone defect repair in a rat model. The findings demonstrate a promising strategy of using aptamer-functionalized bio-nanoparticles for the restoration of bone defects via aptamer-introduced homing of MSCs.