Biomechanical study of 3D-printed titanium alloy pad for repairing glenoid bone defect.

Background: The purpose of this study was to investigate the effect of 3D-printed technology to repair glenoid bone defect on shoulder joint stability. Methods: The shoulder joints of 25 male cadavers were tested. The 3D-printed glenoid pad was designed and fabricated. The specimens were divided into 5 groups. Group A: no bone defect and the structure of the glenoid labrum and joint capsule was intact; Group B: Anterior inferior bone defect of the shoulder glenoid; Group C: a pad with a width of 2 mm was installed; Group D: a pad with a width of 4 mm was installed; Group E: a pad with a width of 6 mm was installed. This study measured the distance the humeral head moved forward at the time of glenohumeral dislocation and the maximum load required to dislocate the shoulder. Results: The shoulder joint stability and humerus displacement was significantly lower in groups B and C compared with group A (p < .05). Compared with group A, the stability of the shoulder joint of group D was significantly improved (p < .05). However, there was no significant difference in humerus displacement between groups D and A (p > .05). In addition, compared with group A, shoulder joint stability was significantly increased and humerus displacement was significantly decreased in group E (p < .05). Conclusion: The 3D-printed technology can be used to make the shoulder glenoid pad to perfectly restore the geometric shape of the shoulder glenoid articular surface. Moreover, the 3D-printed pad is 2 mm larger than the normal glenoid width to restore the initial stability of the shoulder joint.

Reconstruction of recurrent shoulder dislocation with glenoid bone defect with 3D-printed titanium alloy pad: outcomes at 2-year minimum follow-up.

BACKGROUND: To evaluate the outcome of shoulder arthroscopy-assisted implantation of three-dimensional (3D)-printed titanium pads for recurrent shoulder dislocation with glenoid bone defects. METHODS: From June 2019 to May 2020, the clinical efficacy of 3D printed titanium pad implantation assisted by shoulder arthroscopy, for the treatment of recurrent shoulder dislocations with shoulder glenoid defects was retrospectively analyzed. The American Shoulder and Elbow Surgeons (ASES) shoulder, Rowe, and Constant scores were recorded before surgery and at 3 months, 6 months, 1 year, and 2 years after surgery. 3D computed tomography (CT) and magnetic resonance imaging were used to evaluate the location of the glenoid pad, bone ingrowth, joint degeneration, and osteochondral damage. RESULTS: The mean age of the 12 patients was 21.4 (19-24) years and the mean follow-up time was 27.6 (24-35) months. The Visual Analog Scale score significantly improved from 5.67 ± 1.98 preoperatively to 0.83 ± 0.58 postoperatively (p = 0.012). The postoperative ASES score was significantly increased to 87.91 ± 3.47 compared with preoperative ASES score (46.79 ± 6.45) (p < 0.01). Rowe and Constant scores also improved from 22.5 ± 12.34 and 56.58 ± 7.59 preoperatively to 90.83 ± 4.69 and 90.17 ± 1.89 at 2 years postoperatively, respectively. CT performed 2 years after surgery showed that the pad perfectly replenished the bone-defective part of the shoulder glenoid and restored the articular surface curvature of the shoulder glenoid in the anterior-posterior direction, and the bone around the central riser of the pad was tightly united. Magnetic resonance imaging 2 years after surgery showed that the humeral head osteochondral bone was intact, and there was no obvious osteochondral damage. CONCLUSIONS: 3D printed titanium pads are a reliable, safe, and effective surgical procedure for treating recurrent shoulder dislocations with glenoid bone defects.

Cobalt-Catalyzed Asymmetric Remote Borylation of Alkyl Halides.

Enantioselective functionalization of racemic alkyl halides is an efficient strategy to assemble complex chiral molecules, but remains one of the biggest challenges in organic chemistry. The distant and selective activation of unreactive C-H bonds in alkyl halides has received growing interest as it enables rapid generation of molecular complexity from simple building blocks. Here, we reported a cobalt-catalyzed remote borylation of alkyl (pseudo)halides (alkyl-X, X=I, Br, Cl, OTs) with pinacolborane (HBpin) and presented a robust approach for the generation of valuable chiral secondary organoboronates from racemic alkyl halides. This migration borylation reaction is compatible with primary, secondary, and tertiary bromides, offering direct access to a broad range of alkylboronates. The extension of this catalytic system to the borylation of aryl halides was also demonstrated. Preliminary mechanistic studies revealed that this remote borylation involved a radical reaction pathway.

A Modified Endoscopic Technique with Three Incisions for Rockwood Types III and V Acromioclavicular Joint Dislocation.

OBJECTIVE: Acromioclavicular joint dislocation is one of the most common shoulder injuries in young men. With the advancement of minimally invasive technology, arthroscopy of acromioclavicular joint dislocation has been recognized for its good curative effect. This study aimed to explore the technical details and clinical efficacy of a modified minimally invasive endoscopic treatment for acromioclavicular joint dislocation. METHODS: Clinical data of patients receiving the three-incision endoscopic treatment were retrospectively reviewed between July 2013 and July 2019. A total of 72 patients with acromioclavicular joint dislocation of Rockwood type III (n = 42) and type V (n = 30) were included in this study. Postoperative routine radiography was performed to evaluate acromioclavicular joint reduction and fixation. In addition, functional recovery of the shoulder joint was assessed using the American Shoulder and Elbow Surgeons (ASES) and Constant-Murley scores. Differences between the preoperative and postoperative data were compared using paired t-tests. RESULTS: All patients underwent loop plate elastic fixation under endoscopy during 24 to 48 months of follow-up. Postoperative radiography showed that the acromioclavicular joint achieved anatomical reduction. The ASES score (91.1 ± 4.2) was significantly improved compared to the preoperative ASES score (62.4 ± 3.1) (t = 46.65, P < 0.0001). The Constant-Murley score (93.1 ± 4.6) was also significantly higher than that before the operation (40.7 ± 6.4) (t = 56.41, P < 0.0001). No postoperative complications occurred. During follow-up, four patients had mild acromioclavicular joint degeneration but no obvious pain symptoms. CONCLUSION: The modified three-incision endoscopic technique optimizes the surgical incision, reduces trauma, is minimally invasive, and provides rapid rehabilitation with satisfactory clinical outcomes.

Arthroscopic Subscapularis Augmentation Using the Long Head of the Biceps Tendon for Anterior Shoulder Instability.

The limitations of transferring the coracoid process along with the conjoined tendon are coracoacromial arch damage, technical difficulty, and nerve injury. The long head of the biceps tendon (LHBT) proximal transposition technique has a weaker sling effect and a risk of nerve injury. The arthroscopic subscapularis augmentation technique may have risks of shoulder external rotation restriction and subscapularis transection. Herein, we introduce an arthroscopic technique for the transfer of the LHBT for subscapularis augmentation to address these risks. Indications of this technique were patients younger than 45 years of age who engage in competitive sports, require forceful external rotation and abduction, have a related capsule-ligament insufficiency, and have a glenoid bone loss <25%. The steps include detaching the LHBT at the upper edge of the pectoralis major, transecting and braiding the LHBT, establishing a scapular tunnel, placing a guide suture through the upper third of the subscapular and scapular tunnel, passing the LHBT through the established tunnels, and fixating the LHBT. This technique achieves stability of the anterior shoulder by transecting and transferring the distal end of the LHBT to press on the upper third of the subscapularis muscle.

Enantioselective Cobalt-Catalyzed Hydroboration of Ketone-Derived Silyl Enol Ethers.

Catalytic asymmetric hydroboration of alkenes is a powerful tool for the synthesis of natural products, agrochemicals, and pharmaceuticals via the versatile transformations of chiral alkyl boronic esters. However, the scope of available alkenes is limited to styrenes, activated alkenes, and compounds with directing groups. The catalytic enantioselective hydroboration of heteroatom-substituted alkenes is rarely explored and those catalyzed by earth-abundant metals are yet to be reported. Herein, we report a cobalt-catalyzed asymmetric hydroboration of ketone-derived silyl enol ethers and provide a convenient approach to access valuable enantiopure ß-hydroxy boronic esters. This protocol features mild reaction conditions, a broad substrate scope, and excellent enantioselectivities (up to 99 % ee). This approach was applied in the successful synthesis of salmeterol and albuterol, demonstrating its potential to streamline complex molecule synthesis.

Reconstruction of traumatic medial malleolus loss using the bone sliding technique: A case report.

INTRODUCTION: Open injury of the medial malleolus is relatively rare, and it can cause instability of the ankle joint and affect the walking function of the lower extremity. We describe an original plan for the reconstruction of medial malleolus defects using the bone sliding technique and report as follows. CASE PRESENTATION: A 48-year-old female presented with an isolated open injury to her right ankle by a traffic accident. The skin of the medial ankle was severely contaminated with mud, and the medial malleolus, part of the Talus's cartilage and soft tissue, were defective. The anterior tibial artery was cut, and the anterior and posterior tibial tendons were ruptured. CONCLUSION: We describe the reconstruction of the medial malleolus using a bone sliding technique. At two years follow-up, she had a good outcome with a nearly painless, stable ankle with functional plantarflexion but restricted dorsiflexion. The original method is a new choice for the reconstruction of the medial malleolus.

USP13 mediates PTEN to ameliorate osteoarthritis by restraining oxidative stress, apoptosis and inflammation via AKT-dependent manner.

Osteoarthritis is a chronic, systemic and inflammatory disease. However, the pathogenesis and understanding of RA are still limited. Ubiquitin-specific protease 13 (USP13) belongs to the deubiquitinating enzyme (DUB) superfamily, and has been implicated in various cellular events. Nevertheless, its potential on RA progression has little to be investigated. In the present study, we found that USP13 expression was markedly up-regulated in synovial tissue samples from patients with RA, and was down-regulated in human fibroblast-like synoviocytes (H-FLSs) stimulated by interleukin-1ß (IL-1ß), tumor necrosis factor alpha (TNF-α) or lipopolysaccharide (LPS). We then showed that over-expressing USP13 markedly suppressed inflammatory response, oxidative stress and apoptosis in H-FLSs upon IL-1ß or TNF-α challenge, whereas USP13 knockdown exhibited detrimental effects. In addition, USP13-induced protective effects were associated with the improvement of nuclear factor erythroid 2-related factor 2 (Nrf-2) and the repression of Casapse-3. Furthermore, phosphatase and tensin homolog (PTEN) expression was greatly improved by USP13 in H-FLSs upon IL-1ß or TNF-α treatment, whereas phosphorylated AKT expression was diminished. In response to IL-1ß or TNF-α exposure, nuclear transcription factor κB (NF-κB) signaling pathway was activated, whereas being significantly restrained in H-FLSs over-expressing USP13. Mechanistically, USP13 directly interacted with PTEN. Of note, we found that USP13-regulated cellular processes including inflammation, oxidative stress and apoptotic cell death were partly dependent on AKT activation. Furthermore, USP13 over-expression effectively inhibited osteoclastogenesis and osteoclast-associated gene expression. The in vivo experiments finally confirmed that USP13 dramatically repressed synovial hyperplasia, inflammatory cell infiltration, cartilage damage and bone loss in collagen-induced arthritis (CIA) mice via the same molecular mechanisms detected in vitro. Taken together, these findings suggested that targeting USP13 may provide feasible therapies for RA.

Treatment of middle-super thoracic fractures associated with the sternum fracture.

To analyze the characteristics and treatment of middle-super thoracic fractures associated with the sternum fracture, twenty six patients with middle-super thoracic fractures associated with the sternum fracture were retrospectively reviewed. The intimate information of patients including age, gender, cause of injury, site of the sternal fracture, level and type of thoracic vertebral fracture, spinal cord injury and associated injuries were included in the analysis. There were 12 compressed fractures, 11 fracture-dislocations, two burst fracture and one burst-dislocation in this study. Six patients had a complete lesion of the spinal cord, nine sustained a neurologically incomplete injury and 11 were neurologically intact. Nine patients were treated non-operatively and 17 were underwent surgery. All patients were followed up for 8~99 months. Our results showed that road traffic accidents (RTA) and fall were the dominated in the causes. All six patients with a complete paralytic lesion were not recovered with any significant function. Four out of eleven neurologically intact patients had local pain although ten of them remained normal function and one patient turn up tardive paralysis. One of nine patients with incomplete paraplegia returned to normal and four recovered with some function. These study suggested that the sternum is one of the important parts in constructing thoracic cage and plays an important role in maintain the stabilization of the thoracic vertebra. Because of the unique anatomy and biomechanics of the thoracic cage, the classification commonly applied to thoracic vertebra fractures is not suitable for middle-super thoracic fractures associated with the sternum fracture. Middle-super thoracic fractures associated with the sternum fracture was marked by violent force, severe fractures of spine, severe injuries of spinal cord and high incidence of associated injuries. These cases confirm the existence and clinical relevance of the fourth column of the thoracic spine and its role for spinal stability in the patient with middle-super thoracic fracture.

Effect of culture complex of BMSCs and sodium hydroxide- and GRGDSPC-treated PET on the reconstruction of injured anterior cruciate ligament in a rabbit model.

Ligament reconstruction is an effective therapy for anterior cruciate ligament (ACL) rupture. Polyethylene terephthalate (PET) artificial ligaments have recently gained popularity in clinical ACL reconstruction for its advantage in the improvement of keen function. However, the application of PET in clinical treatment is limited by its poor bioactivity and biocompatibility. Recently, bone marrow-derived mesenchymal stem cells (BMSCs) have been widely studied in regenerative medical therapy due to their multi-lineage differentiation. Previous study also indicated that BMSCs may promote the healing of tendon-bone interface of injured ligament. We speculate that BMSCs may enhance the curative effect of PET artificial ligament on the tendon-bone-healing in ligament reconstruction. In this study, the PET materials were first modified with sodium hydroxide hydrolysis and GRGDSPC peptide which was able to improve its bioactivity and biocompatibility. Then, the effects of modified PET materials on the adhesion, proliferation and differentiation of BMSCs were examined. The in vitro co-culture of BMSCs and modified PET showed the modified PET promoted the adhesion, proliferation and differentiation of BMSCs. Further, the effect of culture complex of BMSCs and modified PET artificial ligament co-culture system on the injured ligament reconstruction was investigated in vivo. Results showed not only better growth and differentiation of BMSCs but also satisfactory healing of the injured ligament was observed after implantation of this culture complex into the injured ligament of rabbits. Our study provides a brand-new solution for ACL reconstruction.

Fast pinless external fixation for open tibial fractures: preliminary report of a prospective study.

A major drawback of conventional fixator system is the penetration of fixator pins into the medullary canal. The pins create a direct link between the medullary cavity and outer environment, leading to higher infection rates on conversion to intramedullary nailing. This study was designed to prospectively evaluate the role of new rapid pinless external fixators in primary stabilization of open tibial shaft fractures. In our study, a prospective study of 96 consecutive patients of open tibial shaft fractures treated with new rapid pinless external fixator and reamed intramedullary nail was carried out. The bone healing status, ability to maintain alignment were examined for radiologic outcome, whereas initial management, length of hospital stay, associated morbidity, range of knee and ankle motion, time to partial and full weight-bearing, employment status and perioperative and postoperative complications were used for clinical evaluation. We followed up for over two years for the patients underwent clinical and radiologic after the surgery. The mean hospital stay was 15 days (ranges, 8-68). Bone healing was achieved for all cases except 3 patients who were lost to follow-up study. No patient suffered compartment syndromes. There was no statistically significance in range of motion among the knees of injury and uninjured limbs at final follow-up (P > 0.05). To the last follow-up, there were no cases of deep infection or implant-related fractures. Seventy-one patients who were employed before the injury returned to work after the operation, 16 had changed to less strenuous work. We concluded that better results can be achieved on clinical and radiologic evaluation of primary stabilization with rapid pinless external fixator and early exchange reamed intramedullary nail for suitable patients with open tibial shaft fractures. The incident rate of relative complications is low. The rapid pinless external fixator can be combined favorably with the reamed intramedullary nail and is a valuable addition to the conventional external fixator systems.

[Treatment and classification of thoracic fracture accompanied with sternum fracture].

OBJECTIVE: To determine the characteristics, classification, and treatment of thoracic fracture accompanied with sternum fracture. METHODS: Data of 32 patients with thoracic fractures accompanied with sternum fracture were reviewed. Patients information such as age, gender, cause of injury, site of sternum fracture, level and type of thoracic vertebral fracture, spinal cord injury and associated injuries was included in the analysis. Of the 32 patients, 13 had compressed fractures, 13 had fracture-dislocations, 5 had burst fracture and 1 had burst-dislocation. Six patients had a complete lesion of the spinal cord, 13 sustained a neurologically incomplete injury, and the other 13 were neurologically intact. Ten patients were treated nonoperatively and the other 22 surgically. RESULTS: All patients were followed up for 10-103 months. Road traffic accidents and falling dominated among the causes. All patients were accompanied with other injuries. None of the 6 patients with a complete paralitic lesion regained any significant function. Of the 13 neurologically intact patients, 5 had local pain although 12 of them remained normal function. One patient showed tardive paralysis. Three of the 13 patients with incomplete paraplegia returned to normal, 5 regained some function and 5 did not recover. CONCLUSION: Thoracic fractures accompanied with sternum fracture are marked by violent force, severe fracture of the spine, severe injuries of the spinal cord, and high incidence of other injuries. The new classification method is more suitable to thoracic fractures accompanied with sternum fracture,and confirms the existence and clinical relevance of the 4th column of the thoracic spine and its role in providing spinal stability in patients with thoracic fracture.