Stabilizing Mechanisms in Patients Treated Using Hill-Sachs Remplissage With Bankart Repair in Abduction-External Rotation Position.

BACKGROUND: Hill-Sachs lesion (HSL) remplissage with Bankart repair (RMBR) provides a minimally invasive solution for treating HSLs and glenoid bone defects of <25%. The infraspinatus tendon is inserted into the HSL during the remplissage process, causing the infraspinatus to shift medially, leading to an unknown effect on glenohumeral alignment during the resting abduction-external rotation (ABER) and muscle-active states. PURPOSE/HYPOTHESIS: The purpose of this study was to evaluate the possible check-rein effect and muscle-active control in stabilizing the glenohumeral joint after RMBR in vivo. We hypothesized that the check-rein effect and active control would stabilize the glenohumeral joint in the ABER position in patients after RMBR. STUDY DESIGN: Controlled laboratory study. METHODS: We included 42 participants-22 patients in group A who met the inclusion criteria after RMBR and 20 healthy participants in group B without shoulder laxity. Three-dimensional magnetic resonance imaging was performed to analyze the alignment relationship of the glenohumeral joint with and without muscular activity. Ultrasonic shear wave elastography was used to evaluate the elastic properties of the anterior capsule covered with the anterior bands of the inferior glenohumeral ligament. RESULTS: Patients who underwent RMBR demonstrated more posterior (-1.81 ± 1.19 mm vs -0.76 ± 1.25 mm; P = .008) and inferior (-1.05 ± 0.62 mm vs -0.45 ± 0.48 mm; P = .001) shifts of the humeral head rotation center and less anterior capsular elasticity (70.07 ± 22.60 kPa vs 84.01 ± 14.08 kPa; P = .023) than healthy participants in the resting ABER state. More posterior (-3.17 ± 0.84 mm vs -1.81 ± 1.19 mm; P < .001) and less-inferior (-0.34 ± 0.56 mm vs -1.05 ± 0.62 mm; P < .001) shifts of the humeral head rotation center and less anterior capsular elasticity (36.57 ± 13.89 kPa vs 70.07 ± 22.60 kPa; P < .001) were observed in the operative shoulder during muscle-active ABER than in resting ABER states. CONCLUSION: The check-rein effect and muscle-active control act as stabilizing mechanisms in RMBR during the ABER position. CLINICAL RELEVANCE: Stabilizing mechanisms in RMBR during the ABER position include the check-rein effect and muscle-active control.

Thrombin immobilized polydopamine-diatom biosilica for effective hemorrhage control.

In this study, an efficient composite hemostatic material (DA-diatom-T) was prepared, using a polydopamine layer as a linker to immobilize thrombin on the surface of diatom biosilica. DA-diatom-T retained the porous structure of the diatom with high water absorption capacity, which can absorb 31 times its own weight of water. The thrombin activity of DA-diatom-T was as high as 5.81 U mg-1 that could be maintained at 67% after 30 days at room temperature. DA-diatom-T exhibited non-toxicity to mouse fibroblast cell lines, favorable hemocompatibility and fast procoagulant ability. DA-diatom-T could promote the initiation of the coagulation process and increase platelet activity and blood clot strength to form a physical barrier at the wound. In an in vivo study, DA-diatom-T could significantly reduce the clotting time and reduce the bleeding volume. The above results showed that DA-diatom-T had potential as a new hemostatic material.

Clinical outcomes of a combined arthroscopic and mini-open Outerbridge-Kashiwagi procedure for elbow osteoarthritis.

BACKGROUND: To evaluate the short-term clinical outcomes of a modified Outerbridge-Kashiwagi (O-K) procedure in the treatment of elbow osteoarthritis. METHODS: Between January 2012 and December 2016, 27 patients with elbow osteoarthritis were treated with a modified O-K procedure combining mini-open and arthroscopic technique in our institution. All patients with primary osteoarthritis and post-traumatic degenerative osteoarthritis of the elbow were included in the study if they had undergone the modified O-K procedure. Clinical outcomes were assessed using the visual analog scale (VAS), degree of flexion, extension loss, arc of motion, Mayo Elbow Performance Score (MEPS), and radiographs. RESULTS: Twenty-five patients with a mean age of 47.2 years (range, 21-69 years) at surgery were followed up for a mean of 54.5 months (range, 27-86 months). The VAS improved from 8.0 ± 1.4 (range, 6-10) preoperatively to 1.3 ± 1.1 (range, 0-3) at the final follow-up (P < .001), degree of flexion from 115.2° ± 12.0° (range, 90°-135°) to 130.6° ± 6.3° (range, 120°-140°) (P < .001), extension loss from 31.2° ± 15.0° (range, 10°-60°) to 10.2° ± 7.7° (range, 0°-30°) (P < .001), arc of motion from 84.0° ± 18.8° (range, 55°-120°) to 120.4° ± 9.3° (range, 105°-135°) (P < .001), and MEPS from 55.8 ± 8.1 (range, 40-70) to 88.4 ± 7.2 (range, 70-100) (P < .001). Radiographs at the final follow-up showed that 9 patients (36%) had significant recurrence of bone formation within the fenestration of the olecranon fossa. One patient developed delayed-onset ulnar neuropathy, with only slight numbness in the ulnar nerve distribution 6 months after surgery. CONCLUSIONS: The modified O-K procedure is safe and effective in pain relief and function restoration in patients with elbow osteoarthritis.

Experimental study of expression profile and specific role of human microRNAs in regulating atrophic bone nonunion.

The expression profile and specific roles of microRNAs (miRNAs) in regulation of atrophic bone nonunion are not fully understood. Here, we present evidence that miRNAs are involved in regulation of several osteogenic genes and may contribute to the development of atrophic bone nonunion.The miRNA expression profile of repairing tissues in atrophic bone nonunion patients (group A) and in callus tissues from patients with healed fractures (group B) were quantitatively measured. microRNA microarrays were used to identify differentially expressed miRNAs, and the bioinformatics methods were used to predict the potential target genes. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot, and dual-luciferase reporter assay were performed in human bone marrow stromal cells (hBMSCs) to validate the microarray results.Nine miRNAs in group A were up-regulated 1.5 times compared to group B, while the other 9 miRNAs in group A were down-regulated 1.5 times. Several target regions of these miRNAs were identified in the osteogenic genes, as well as in the other genes in their families or related regulatory factors. Four miRNAs (hsa-miR-149, hsa-miR-221, hsa-miR-628-3p, and hsa-miR-654-5p) could play important roles in regulating bone nonunion development. hBMSCs transfected with these miRNAs significantly decreased mRNA levels of alkaline phosphatase, liver/bone/kidney (ALPL), platelet derived growth factor subunit A (PDGFA), and bone morphogenetic protein 2 (BMP2). Lower protein expression levels were observed using western blotting, confirming that ALPL, PDGFA, and BMP2 were directly targeted by hsa-miR-149, hsa-miR-221, and hsa-miR-654-5p, respectively.In summary, hsa-miR-149, hsa-miR-221, and hsa-miR-654-5p may play important biological roles by repressing osteogenic target genes ALPL, PDGFA, and BMP2, and, therefore, contributing to progression of atrophic bone nonunion.

Functional double-bundle anterior cruciate ligament reconstruction using hamstring tendon autografts with preserved insertions is an effective treatment for tibiofemoral instability.

PURPOSE: The aim of this study was to introduce a modified anatomical anterior cruciate ligament reconstruction using functional double bundles (F-DBACLR), which achieved sequential tensioning at all flexion angles postoperatively, and compare its clinical outcomes with the anatomical single-bundle technique (A-SBACLR). METHODS: A total of 156 patients with an ACL injury underwent ACLR (A-SB group, n = 78; F-DB group, n = 78). All operations were performed by anatomically identifying the ACL footprints and fixing the graft at a pre-determined degree of knee flexion. Two observers blinded to the patient identities examined the patients preoperatively and during follow-up (median 28.2 months; range 26-31 months). Multiple subjective and objective clinical evaluation tests and assessment of clinical outcomes concerning the translational and rotational stability of the knee including the International Knee Documentation Committee (IKDC) questionnaire, Lysholm Knee Scoring Scale, Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Scale, KT-1000 laxity measurements, Lachman test and pivot-shift test were performed preoperatively and postoperatively. RESULTS: Preoperatively, no differences were found between the two groups. During the 2-year observation period, patients in the F-DB group revealed better clinical outcomes in terms of the Tegner Activity Scale Score, IKDC, KOOS and Lysholm Knee Scoring Scale. Similar results were shown in regard to the translational stability in both groups, while the F-DB group had more rotational stability at 2 years of follow-up. CONCLUSIONS: The clinical outcomes indicated that F-DBACLR is clinically practicable and advantageous in the treatment of the ACL-deficient knee. LEVEL OF EVIDENCE: II.

Multifunctional quercetin conjugated chitosan nano-micelles with P-gp inhibition and permeation enhancement of anticancer drug.

In this study, quercetin-chitosan conjugate (QT-CS) was synthesized for oral delivery of doxorubicin (DOX) to improve its oral bioavailability by increasing its water solubility, opening tight junction and bypassing the P-glycoprotein (P-gp). The prepared QT-CS self-assembled into micelles which could encapsulate DOX with high encapsulation rate, small particle size (136.9 nm) and strong zeta potential (+16.2 mV). QT-CS-DOX micelles displayed sustained-release profile in gastrointestinal simulation fluid (pH 1.2/pH 7.4). QT-CS micelles could promote cellular uptake of doxorubicin, which was 2.2 folds higher than that of free doxorubicin. The trans epithelial electrical resistance (TEER) value of Caco-2 monolayer cells was significantly reduced (about 57%) by drug loaded QT-CS micelles, leading to a high apparent permeability coefficient (Papp) of doxorubicin, which was 10.17 folds higher than that of free doxorubicin. Above results indicate that QT-CS micelles are promising vehicles for the oral delivery of insoluble anticancer drugs.

Sintered porous Ti6Al4V scaffolds incorporated with recombinant human bone morphogenetic protein-2 microspheres and thermosensitive hydrogels can enhance bone regeneration.

A well-controlled powder sintering technique was used to fabricate porous Ti6Al4V scaffold. The thermosensitive chitosan thioglycolic acid (CS-TA) hydrogel was used as a carrier to inject recombinant human bone morphogenetic protein-2 (rhBMP-2) microspheres into pores of the Ti6Al4V scaffold at 37 °C, and then the porous Ti6Al4V/rhBMP-2 loaded hydrogel composite was obtained. The bare Ti6Al4V scaffold was used as the control. The characteristics and mechanical properties of the scaffold, rheological properties of the hydrogels and the rhBMP-2 loaded hydrogel, the release of the rhBMP-2 loaded hydrogel, and the biological properties of the two types of samples were evaluated by in vitro and in vivo tests. Results indicated that the sintered porous Ti6Al4V had high porosity, large pore size with good mechanical properties. The hydrogel and rhBMP-2 loaded hydrogel showed thermosensity. The rhBMP-2 loaded hydrogel showed a stable and extended release profile without too high burst release of rhBMP-2. Both groups showed good biocompatibility and osteogenic ability. However, according to the results of cell tests and implantation, the group with rhBMP-2 loaded hydrogel had significantly higher cell proliferation rate, faster bone growth speed, and more bone ingrowth at every time point. Therefore, the sintered porous Ti6Al4V scaffolds incorporated with rhBMP-2 microspheres and CS-TA hydrogel was effective in enhancing the bone regeneration, and prospects a good candidate for application in orthopedics.

Arthroscopic Fixation for Tibial Eminence Fractures: Comparison of Double-Row and Transosseous Anchor Knot Fixation Techniques with Suture Anchors.

BACKGROUND Tibial eminence fractures often occur during sports participation, but the optimum choice of technique for treatment is still controversial. The aim of the current work was to compare the clinical outcomes of 2 new arthroscopic anchor fixation techniques for tibial eminence fracture. MATERIAL AND METHODS We included 72 isolated tibial eminence fracture patients treated at our hospital from October 2010 to August 2015; 37 patients received the classic double-row (DR) suture anchor fixation technique and 35 received the transosseous anchor knot (TAK) fixation under arthroscopy. The clinical efficacies of the 2 techniques were assessed by radiographs, Lysholm score, and International Knee Documentation Committee (IKDC) score in follow-ups. RESULTS Patients were followed for 37.6 months (range, 18-54 months). There was no significant difference of the operative time between groups (P=0.169). Postoperative radiographs of all patients showed accurate reduction and fracture healing within 3 months. Lysholm and IKDC scores improved significantly compared with preoperative scores (P<0.001). However, no significant difference in the knee range of motion or improvement of Lysholm and IKDC scores was found between groups (P>0.05). CONCLUSIONS The DR and TAK techniques provide precise reduction and stable fixation methods for treating tibial eminence fractures, and the clinical outcomes of the 2 arthroscopic techniques with suture anchors are satisfactory.

Tibiofemoral joint contact area and stress after single-bundle anterior cruciate ligament reconstruction with transtibial versus anteromedial portal drilling techniques.

BACKGROUND: During single-bundle ACLR, femoral tunnel location plays an important role in restoring the intact knee mechanisms, whereas malplacement of the tunnel was cited as the most common cause of knee instability. The objective of this study is to evaluate, objectively, the tibiofemoral contact area and stress after single-bundle (SB) anterior cruciate ligament reconstruction (ACLR) with femoral tunnel positions drilled by transtibial (TT) or anteromedial (AM) portal techniques. METHODS: Seven fresh human cadaveric knees underwent ACLR by the use of TT or AM portal techniques in a randomized order. These specimens were reused for ACL-R (TT and AM). The tibiofemoral contact area and stresses were gauged by an electronic stress-sensitive film inserted into the joint space. The knee was under the femoral axial compressive load of 1000 N using a biomechanics testing machine at 0°, 10°, 20°, and 30° of flexion. Three conditions were compared: (1) intact ACL, (2) ACLR by the use of the TT method, and (3) ACLR by the use of the AM portal method. RESULTS: Compared with AM portal ACL-reconstructed knees, a significantly decreased tibiofemoral contact area on the medial compartment was detected in the TT ACL-reconstructed knees at 20°of knee flexion (P = .047). Compared with the intact group, the TT ACLR group showed a higher mean stress at 20° and 30° of flexion on the medial compartments (P = .001, P = .003, respectively), while the AM portal ACLR group showed no significant differences at 30° of flexion (P = .073). The TT ACLR group also showed a higher mean maximum stress at 20° of flexion on the medial compartments (P = .047), while the AM portal ACLR group showed no significant differences at this angle(P = .319). DISCUSSION: The alternation of the tibiofemoral joint contact area and stress in reconstructed knees may be caused by the mismatch of the tibiofemoral joint during knee movement procedures compared with intact knees. CONCLUSIONS: SB ACLR by the use of the AM portal method and TT method both alter the tibiofemoral contact area and stress when compared with the intact knee. When compared with the TT technique, ACLR by the AM portal technique more closely restores the intact tibiofemoral contact area and stress at low flexion angles.

Multifunctional chitosan/dopamine/diatom-biosilica composite beads for rapid blood coagulation.

Uncontrollable bleeding is the main cause of death in wars and accidents. The development of emergency material for rapid hemostatic can effectively reduce bleeding-related death. The commercial hemostatic materials available in the market are difficult to meet requirements of rapid hemostasis, good biocompatibility, low cost and ease of use. In this study, we developed chitosan/dopamine/diatom-biosilica composite beads (CDDs) for rapid hemostasis with good biocompatibility. CDDs were prepared by combining chitosan with diatom-biosilica (DB) using dopamine as bio-glue. The porous internal structure of CDDs led to rapid and large amount of water absorption, which contributed to the rapid hemostasis (83 s, 22% of the control group). The hemolytic rate of CDDs was less than 5% and cell viability was above 80%, confirming its good biocompatibility. All the above results indicated that CDDs had potential to develop into safe and non-toxic hemostatic material.

Establishment of a rat model of chronic thoracolumbar cord compression with a flat plastic screw.

Previous studies of animal models of chronic mechanical compression of the spinal cord have mainly focused on cervical and thoracic lesions, but few studies have investigated thoracolumbar injury. The specific pathophysiological mechanism of chronic thoracolumbar cord injury has not yet been elucidated. The purpose of this study was to improve animal models of chronic thoracolumbar cord compression using the progressive screw. A custom-designed flat plastic screw was implanted in the spinal cord between thoracic vertebrae 12 and lumbar 1 of rats. The screw was tightened one complete turn (0.5 mm) every 7 days for 4 weeks to create different levels of chronic spinal cord compression. Following insertion of the screw, there was a significant decline in motor function of the hind limbs, and severe stenosis of micro-computed tomography parameters in the spinal cord. Cortical somatosensory evoked potential amplitudes were reduced remarkably, and latencies were prolonged at 30 minutes after surgery. The loss of motor neurons in the gray matter was marked. Demyelination and cavitation were observed in the white matter. An appropriate rat model of chronic thoracolumbar cord compression was successfully created using the progressive screw compression method, which simulated spinal cord compression injury.

Nasal delivery of analgesic ketorolac tromethamine thermo- and ion-sensitive in situ hydrogels.

Ketorolac tromethamine (KT) was potent to treat moderate to moderately severe pains. However, KT solutions for nasal delivery lost quickly from the nasal route. Thermo- and ion-sensitive in-situ hydrogels (ISGs) are appropriate for nasal drug delivery because the intranasal temperature maintains ∼37 °C and nasal fluids consist of plentiful cations. In this study, a novel nasal thermo- and ion-sensitive ISG of KT was prepared with thermo-sensitive poloxamer 407 (P407) and ion-sensitive deacetylated gellan gum (DGG). The optimal formulation of the KT ISG consisted of 3% (w/v) DGG and 18% (w/v) P407 and its viscosity was up to 7.63 Pas at 37 °C. Furthermore, penetration enhancers and bacterial inhibitors were added and their fractions in the ISG were optimized based on transmucosal efficiencies and toxicity on toad pili. Sulfobutyl ether-ß-cyclodextrin of 2.5% (w/v) and chlorobutanol of 0.5% (w/v) were chosen as the penetration enhancer and the bacterial inhibitor, respectively. The Fick's diffusion and dissolution of KT could drive it continuous release from the dually sensitive ISG according to the in vitro investigation. Two methods, writhing frequencies induced by acetic acid and latency time of tails retracting from hot water, were used to evaluate the pharmacodynamics of the KT ISG on the mouse models. The writhing frequencies significantly decreased and the latency time of tail retracting was obviously prolonged (p<0.05) for the KT ISG compared to the control. The thermo- and ion-sensitive KT ISG had appropriate gelation temperature, sustained drug release, improved intranasal absorption, obvious pharmacodynamic effect, and negligible nasal ciliotoxicity. It is a promising intranasal analgesic formulation.

[Study on the accurate effects of radial shock wave therapy equipment].

The basic mechanical properties of a Radial Shock Wave Therapy Equipment (RSWTE) were experimentally studied in this paper. The output energy of the RSWTE working on the operation frequency of 10 Hz was measured by dynamic pressure transducer under the conditions of different operation pressure. The results showed that both operation pressure and operation frequency have effects on the output energy of the equipment. The output energy increases with the increase of operation pressure, and the magnitude of increased energy decreases with higher operation of frequency. With the increase of operation frequency, the output energy rises up in condition of lower operation pressure and drops off in condition of higher operation pressure. The accurate medical treatment should be selected with the optimized energy and condition according to the treatment requirement to different illness in clinical medical applications.

Controlled-release of bone morphogenetic protein-2 from a microsphere coating applied to acid-etched Ti6AL4V implants increases biological bone growth in vivo.

A central clinical challenge regarding the surgical treatment of bone and joint conditions is the eventual loosening of an orthopedic implant as a result of insufficient bone ingrowth at the bone-implant interface. We investigated the in vivo effectiveness of a coating containing recombinant human bone morphogenetic protein-2 (rhBMP-2)-loaded microspheres applied to acid-etched Ti6Al4V cylinders for implantation. Three groups of rabbits (24 per group) were used for implantation: (1) acid-etched Ti6Al4V implants coated with a mixture of rhBMP-2-loaded microspheres (125 ng rhBMP-2/mg microspheres) and α-butyl cyanoacrylate; (2) acid-etched, uncoated implants; and (3) bare, smooth uncoated implants. After implantation, 12 rabbits from each group were used for bone ingrowth determination at 4, 5, 6, 7, 8, and 12 weeks (2 rabbits per time point), while the remainder were used for histological analysis and push-out testing at 12 weeks. Scanning electron microscopy showed significant improvement in bone growth of the rhBMP-2 microspheres/α-butyl cyanoacrylate group compared with the other groups (p<0.01). Histological analysis and push-out testing also demonstrated enhanced bone growth of the rhBMP-2 group over that in the other two groups (p<0.01). The rhBMP-2 group showed the most significant bone growth, suggesting that coating acid-etched implants with a mixture of rhBMP-2-loaded microspheres and α-butyl cyanoacrylate may be an effective method to improve the osseointegration of orthopedic implants.

[Treatment of infected total knee arthroplasty with a self-made, antibiotic-loaded cement articulating spacer].

OBJECTIVE: To study the efficacy of self-made, antibiotic-loaded cement articulating spacer in the treatment of infected total knee arthroplasty. METHODS: The self-made molds were used to form the spacer during the operation. From March 2002 to March 2007, 22 patients with infected knee arthroplasty (10 males with 10 knees, 12 females with 12 knees) were treated with this kind of spacer in our center. The mean age of the patients was 59.6 years old (33 to 75 years old). The interval time between primary arthroplasty and first onset of infective syndrome was 6.7 months (1 to 14 months). The diagnosis was established by the clinical presentation,serum laboratory inflammatory markers (white blood cell count,erythrocyte sedimentation rate and C-reactive protein) and knee aspiration. The serum laboratory inflammatory markers were used to measure the systemic response to infection. Clinical and radiographic follow-up was regularly performed by HSS score system and X-ray. RESULTS: All the patients were followed, the average interval between debridement and reimplantation was 4.7 months (3 to 9 months) and the infection control rate was 100% after the implantation of spacer. The average follow-up duration after reimplantation was 29.8 months (10 to 64 months) and there was no recurrence of infection at the latest follow-up. The HSS score increased from 40.5+/-5.9 to 65.8+/-7.5 after the implantation of spacer, furthermore, the score reached 88.7+/-5.1 in average at the latest follow-up. The patient satisfaction rate was 95.3%. CONCLUSION: This self-made molds and spacers is a reliable approach for the management of infected knee arthroplasty with some virtues, such as providing a mobile and functional joint through the treatment course, decreasing the difficulty of reimplantation, avoiding of a long-term post-operative infusion and high effective for eradicating infection.

Proteomic analysis of synovial fluid: insight into the pathogenesis of knee osteoarthritis.

PURPOSE: We conducted a proteomic analysis of synovial fluid (SF) to identify differentially expressed proteins and analyse their correlation with osteoarthritis (OA) severity. Our primary purpose was to gain insight into the pathogenesis of OA. METHODS: SF samples were acquired from 12 knee OA patients and 12 non-OA controls (ten had a meniscus injury, two had a discoid meniscus and all exhibited intact articular cartilage) and sequentially subjected to two-dimensional electrophoresis (2-DE). The radiographic grading of knee OA was performed using the Kellgren-Lawrence criteria. Differentially expressed proteins were identified by matrix-assisted laser desorption/ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Proteins of interest identified from SF were detected using an enzyme-linked immunosorbent assay (ELISA). RESULTS: A total of 31 protein spots showed significant differences (p < 0.05) between the sample groups; 25 of the 31 spots (80.6 %) were identified as proteins of interest. Among them 20 corresponded to up-regulation and five to down-regulation in OA samples. HLA-DR was one of the proteins up-regulated, which was confirmed by ELISA. CONCLUSIONS: These observations have implications in delineating the protein expression underlying the pathogenesis of OA and facilitate further elucidation of molecular mechanisms involved in disease progression. Substantial alterations of the protein profile in SF may be associated with OA severity.

In vitro sustained release of recombinant human bone morphogenetic protein-2 microspheres embedded in thermosensitive hydrogels.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a critical regulator of osteogenic capacity that is commonly used in bone grafts. The effectiveness of rhBMP-2 may be reduced as it can become unstable and degraded after injection into the body. Microspheres are considered appropriate vehicles for the sustained release of proteins in vivo. In this study, rhBMP-2 microspheres were manufactured using the water-in-oil-in-water (W/O/W) double-emulsion solvent-extraction technique by encapsulation in poly(lactic-co-glycolic) acid (PLGA). The microspheres were then embedded in two hydrogels made of either poloxamer 407 hydrogel or chitosan thioglycolic acid (CS-TA). The encapsulation efficiency and in vitro release of rhBMP-2 were examined and compared with the control release system (rhBMP-2 microspheres alone). The rhBMP-2 microspheres in the CS-TA hydrogel showed the lowest burst release (about 40% in the first 8h) among the three groups. The mechanisms may be the high viscosity of CS-TA hydrogel and the sustained release characteristics of CS-TA itself. The CS-TA hydrogel combined with PLGA microspheres can efficiently encapsulate rhBMP-2, control the burst release at early time points, and provide sustained release in vitro. It may be an appropriate rhBMP-2 vehicle for bone regeneration.

Effect of low-energy shock waves in microfracture holes in the repair of articular cartilage defects in a rabbit model.

BACKGROUND: Microfracture is a type of bone marrow stimulation in arthroscopic cartilage repair. However, the overall concentration of the mesenchymal stem cells is quite low and declines with age, and in the end the lesion is filled by fibrocartilage. The aim of this research was to investigate a novel method of enhancing microfracture by determining whether low-energy shock waves in microfracture holes would facilitate cartilage repair in a rabbit model. METHODS: Full-thickness cartilage defects were created at the medial femoral condyle of 36 mature New Zealand white rabbits without penetrating subchondral bone. The rabbits were randomly divided into three groups. In experimental group A, low-energy shock-wave therapy was performed in microfracture holes (diameter, 1 mm) at an energy flux density (EFD) of 0.095 mJ/mm² and 200 impulses by DolorClast Master (Electro Medical Systems SA, Switzerland) microprobe (diameter, 0.8 mm). In experimental group B, microfracture was performed alone. The untreated rabbits served as a control group. At 4, 8, and 12 weeks after the operations, repair tissues at the defects were analyzed stereologically, histologically, and immunohistochemically. RESULTS: The defects were filled gradually with repair tissues in experimental groups A and B, and no repair tissues had formed in the control group at 12 weeks. Repair tissues in experimental group A contained more chondrocytes, proteoglycans, and collagen type II than those in experimental group B. In experimental group B, fibrous tissues had formed at the defects at 8 and 12 weeks. Histological analysis of experimental group A showed a better Wakitani score (P < 0.05) than in experimental group B at 8 and 12 weeks after the operation. CONCLUSIONS: In the repair of full-thickness articular cartilage defects in rabbits, low-energy shock waves in microfracture holes facilitated the production of hyaline-like cartilage repair tissues more than microfracture alone. This model demonstrates a new method of improving microfracture and applying shock waves in vivo. However, longer-term outcomes require further study.

[Arthroscopic treatment for tibial eminence avulsion fracture using absorbable double suture anchors].

OBJECTIVE: To investigate the outcomes of arthroscopic reduction and internal fixation of tibial eminence avulsion fracture using absorbable double suture anchors. METHODS: Between February 2007 and August 2009, 18 patients with tibial eminence avulsion fracture were treated with arthroscopic reduction and fixation using absorbable double suture anchors. There were 12 males and 6 females with an average age of 30.6 years (range, 17-48 years). The disease causes were traffic accident injury in 4 cases, sport injury in 8 cases, and falling from height injury in 6 cases; the locations were left side in 7 cases and right side in 11 cases. The results of the anterior drawer test and Lachman test were positive. According to Meyers-McKeever classification, 10 cases were rated as type II, 7 as type III, and 1 as type IV fractures. The time from injury to treatment was 6-20 days (mean, 10.2 days). RESULTS: Incision healed primarily. All the patients were followed up 29.1 months (range, 13-43 months). The X-ray films showed good reduction of fracture immediately after operation and fracture healing at 3 months. At the last follow-up, the range of motion of knee was 0-130 degrees. The results of Lachman test and anterior drawer test were negative in 18 cases and 16 cases, respectively; and the results of anterior drawer test were weakly positive in 2 cases. The mean Lysholm score was significantly improved from 53.9 +/- 6.7 preoperatively to 91.6 +/- 4.2 postoperatively (t = 22.100, P = 0.000). The International knee Documentation Committee (IKDC) 2000 subject score improved from 58.1 +/- 3.7 preoperatively to 92.8 +/- 5.9 postoperatively (t = 20.700, P = 0.000). CONCLUSION: Arthroscopic treatment using absorbable double suture anchors for tibial eminence avulsion fracture can provide satisfactory reduction, stable fixation, and good healing of the avulsed fragment, which is a minimally-invasive, simple, and effective treatment for patients with tibial eminence avulsion fracture.