Diagnosis of Developmental Dysplasia of the Hip by Ultrasound Imaging Using Deep Learning.

BACKGROUND: A timely diagnosis of developmental dysplasia of the hip (DDH) is important for satisfactory clinical outcomes. Ultrasonography is a useful tool for DDH screening; however, it is technically demanding. We hypothesized that deep learning could assist in the diagnosis of DDH. In this study, several deep-learning models were assessed to diagnose DDH on ultrasonograms. This study aimed to evaluate the accuracy of diagnoses made by artificial intelligence (AI) using deep learning on ultrasound images of DDH. METHODS: Infants who were up to 6 months old with suspected DDH were included. DDH diagnosis using ultrasonography was performed according to the Graf classification. Data on 60 infants (64 hips) with DDH and 131 healthy infants (262 hips) obtained from 2016 to 2021 were retrospectively reviewed. For deep learning, a MATLAB deep learning toolbox (MathWorks, Natick, MA, US) was used, and 80% of the images were used as training data, with the rest as validation data. Training images were augmented to increase data variation. In addition, 214 ultrasound images were used as test data to evaluate the AI's accuracy. Pre-trained models (SqueezeNet, MobileNet_v2, and EfficientNet) were used for transfer learning. Model accuracy was evaluated using a confusion matrix. The region of interest of each model was visualized using gradient-weighted class activation mapping (Grad-CAM), occlusion sensitivity, and image LIME. RESULTS: The best scores for accuracy, precision, recall, and F-measure were all 1.0 in each model. In DDH hips, the region of interest for deep learning models was the area lateral to the femoral head, including the labrum and joint capsule. However, for normal hips, the models highlighted the medial and proximal areas where the lower margin of the os ilium and the normal femoral head exist. CONCLUSIONS: Ultrasound imaging with deep learning can assess DDH with high accuracy. This system could be refined for a convenient and accurate diagnosis of DDH. LEVEL OF EVIDENCE: Level-Ⅳ.

Influence of adiponectin and inflammatory cytokines in fatty degenerative atrophic muscle.

Tendon rupture and nerve injury cause fatty infiltration of the skeletal muscle, and the adipokines secreted from the infiltrated adipocytes are known to contribute to chronic inflammation. Therefore, in this study, we evaluated the effects of the adipokines on chronic inflammation using a rat sciatic nerve-crushed injury model. In vitro and in vivo experiments showed that the expression of adiponectin was decreased (0.3-fold) and the expression of Il6 (~ 3.8-fold) and Tnf (~ 6.2-fold) was increased in the nerve-crushed group compared to that in the control group. It was also observed that the administration of an adiponectin receptor agonist decreased the levels of Il6 (0.38-fold) and Tnf (0.28-fold) and improved cellular viability (~ 1.9-fold) in vitro. Additionally, in the fatty infiltrated skeletal muscle, low adiponectin levels were found to be associated with chronic inflammation. Therefore, the local administration of adiponectin receptor agonists would prevent chronic inflammation.

How Semantically Labeled Scent-Gender Associations Influence the Evaluations of Scent and Texture.

Sensory evaluation can be influenced by semantic information such as gender descriptions. Gender categories are associated with tactile information (e.g., female = soft/smooth, while male = hard/rough). Feminine scents (e.g., floral) are typically perceived as soft and smooth. Thus, semantic labels of gender (feminine/masculine qualities) may influence congruent sensory evaluation (i.e., female = soft/smooth, male = hard/rough). This study examined how semantically labeled scent-gender associations influence the evaluation of scent and texture. Specifically, we examined whether "feminine" and "masculine" labels applied to neutral scents that have not been associated with gender influence scent and haptic evaluation. Participants sniffed a feminine-labeled or masculine-labeled scent embedded on soft and rough papers. They then evaluated the scent (e.g., gender perception) and texture (e.g., hedonic evaluation). The results demonstrated that participants who sniffed a feminine-labeled (vs. masculine-labeled) scent perceived it as more feminine. However, contrary to our expectations, gender labeling of scent did not influence haptic evaluation. These findings indicate that semantic labeling of scents (i.e., feminine/masculine) may alter the gender perception of a scent but not the tactile evaluation. Practical implications for (online) sensory marketing are discussed.

The predictive value of synovial glucose level in septic arthritis.

The aim of this study was to investigate the ability of the joint fluid glucose level to detect septic arthritis. Thirty joints in 30 patients with suspected septic arthritis were evaluated. When glucose level was less than 40 mg/dl, we performed arthrotomy. Eleven patients had joint fluid glucose levels less than 40 mg/dl. All 11 (100%) had positive joint fluid cultures. Conversely, 19 patients had synovial glucose levels of at least 40 mg/dl. Six (31.6%) of these had positive joint fluid cultures. The remaining 13 were diagnosed with transient synovitis. Patients with joint fluid glucose levels less than 40 mg/dl should be suspected septic arthritis.

Rotator cuff tear healing process with graft augmentation of fascia lata in a rabbit model.

BACKGROUND: Fascia lata augmentation of massive rotator cuff tears has shown good clinical results. However, its biological effect during the early healing process is not clearly understood. The purpose of the study was to evaluate the biological efficacy of fascia lata augmentation during the early healing process of rotator cuff tears using a rabbit rotator cuff defect model. METHODS: The infraspinatus tendon was resected from the greater tuberosity of a rabbit to create a rotator cuff tear. The tendon edge was directly sutured to the humeral head. The rotator cuff repaired site was augmented with a fascia lata autograft (augmentation group, group A). The rotator cuff defect in the contralateral shoulder was repaired without augmentation (reattachment group, group R). A group with intact rotator cuff was set as the control group. Histological examinations and mechanical analysis were conducted 4 and 8 weeks postoperatively. RESULTS: In the HE staining, the tendon maturing score of group A was higher than that of group R at 4 weeks postoperatively. In the safranin O staining, proteoglycan staining at the repaired enthesis in group A at 4 weeks postoperatively was stronger than that in group R. Picrosirius red staining showed that type III and type I collagen in group A was more strongly expressed than that in group R at 4 weeks postoperatively. The ultimate failure load of the infraspinatus tendon-humeral head complex in group A was statistically higher than that in group R at 4 weeks postoperatively. The ultimate failure load of group A was similar to that of the control group. CONCLUSION: The biological and mechanical contribution of fascia lata augmentation for massive rotator cuff tears was analyzed in this study. Type III collagen was reported to be expressed during the tendon healing process. Although the biological action similar to natural ligament healing occurred around the fascia lata grafts, type III collagen was gradually replaced by type I collagen as the tissue matured. Our results suggest that fascia lata augmentation could stimulate biological healing and provide initial fixation strength of the repaired rotator cuff.

The smallest de novo 20q11.2 microdeletion causing intellectual disability and dysmorphic features.

The 20q11.2 microdeletion is a rare chromosomal aberration characterized by intellectual disability (ID), motor developmental delay, neonatal feeding problems, and facial dysmorphism. Here, a 2-year- and 6-month-old Japanese girl with a 1.2 Mb microdeletion of 20q11.2 showed ID, motor developmental delay, and distinctive facial features without feeding problems. The deleted region was identified by array-based comparative genomic hybridization and is the smallest reported for a 20q11.2 microdeletion.

Effect of platelet-rich plasma on degeneration change of rotator cuff muscles: In vitro and in vivo evaluations.

Atrophy with fatty degeneration is often seen in rotator cuff muscles with torn tendons. PRP has been reported to enhance tissue repair processes after tendon ruptures. However, the effect of PRP on atrophy and fatty degeneration of the muscle is not yet known. The aim of this study is to examine the effect of PRP on degeneration change of rotator cuff muscles in vitro and in vivo. A murine myogenic cell line and a rat rotator cuff tear model were used in this study and PRP was administrated into subacromial space which is widely used in clinical practice. In in vitro study, administration of PRP to C2C12 cells stimulated cell proliferation while inhibited both myogenic and adipogenic differentiation. In in vivo study, administration of PRP suppressed Oil Red-O positive lipid droplet formation. The expression of adipogenic genes was also decreased by PRP administration. In conclusion, PRP promoted proliferation of myoblast cells, while inhibiting adipogenic differentiation of myoblast cells and suppressing fatty degeneration change in rat torn rotator cuff muscles. Further investigations are needed to determine the clinical applicability of the PRP. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1806-1815, 2017.

Rotator cuff repair using cell sheets derived from human rotator cuff in a rat model.

To achieve biological regeneration of tendon-bone junctions, cell sheets of human rotator-cuff derived cells were used in a rat rotator cuff injury model. Human rotator-cuff derived cells were isolated, and cell sheets were made using temperature-responsive culture plates. Infraspinatus tendons in immunodeficient rats were resected bilaterally at the enthesis. In right shoulders, infraspinatus tendons were repaired by the transosseous method and covered with the cell sheet (sheet group), whereas the left infraspinatus tendons were repaired in the same way without the cell sheet (control group). Histological examinations (safranin-O and fast green staining, isolectin B4, type II collagen, and human-specific CD31) and mRNA expression (vascular endothelial growth factor; VEGF, type II collagen; Col2, and tenomodulin; TeM) were analyzed 4 weeks after surgery. Biomechanical tests were performed at 8 weeks. In the sheet group, proteoglycan at the enthesis with more type II collagen and isolectin B4 positive cells were seen compared with in the control group. Human specific CD31-positive cells were detected only in the sheet group. VEGF and Col2 gene expressions were higher and TeM gene expression was lower in the sheet group than in the control group. In mechanical testing, the sheet group showed a significantly higher ultimate failure load than the control group at 8 weeks. Our results indicated that the rotator-cuff derived cell sheet could promote cartilage regeneration and angiogenesis at the enthesis, with superior mechanical strength compared with the control. Treatment for rotator cuff injury using cell sheets could be a promising strategy for enthesis of tendon tissue engineering. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:289-296, 2017.

High-resolution ultrasound in the diagnosis of trigger finger and evaluation of response to steroid injection.

OBJECTIVE: No studies have reported the use of ultrasound for the evaluation of trigger finger after steroid injection. We evaluated the clinical features and ultrasound appearance of trigger finger before and after steroid injection under ultrasound guidance. MATERIALS AND METHODS: Thirty-eight digits with triggering were included. A single steroid injection into the tendon sheath was administered. Ultrasound findings and clinical symptoms, including pain, triggering, and the Quinnell score, were analyzed before injection and at 1 and 3 weeks after injection. RESULTS: Ultrasound indicated that the thickness of the flexor tendons and the thickness of A1 pulleys were significantly greater in the trigger fingers than in controls before steroid injection. Three weeks after injection, these two parameters decreased, and there was no significant difference in the two parameters between the trigger finger and the controls. The visual analogue scales at 1 and 3 weeks after the injection were significantly lower than those before the injection. The Quinnell grading system scores significantly improved at 1 and 3 weeks after injection compared with the scores before injection. Moreover, a tendency was seen for the more clinically severe cases to show more swelling of the tendon and pulley. CONCLUSION: In conclusion, ultrasound assessments could reveal that the thickened A1 pulley and flexor tendon significantly improved after steroid injection, which enables us to confirm the therapeutic effects of the steroid injection. Therefore, ultrasound assessments can be a useful adjunct to understand the response to treatment with the steroid injection.

Ultrasound measurement of median nerve cross-sectional area at the inlet and outlet of carpal tunnel after carpal tunnel release compared to electrodiagnostic findings.

INTRODUCTION: Ultrasound measurement of the cross-sectional area (CSA) of the median nerve can give information about regeneration of the nerve after carpal tunnel release (CTR), but the changes at selected follow-up points up to 1 year compared to electrodiagnostic findings are not known. We postoperatively measured the CSA of the median nerve with ultrasound and compared the measurements with electrophysiological findings over 12 months after open CTR. MATERIALS AND METHODS: In 21 hands that underwent open CTR, the CSA of the median nerve was measured at the inlet (proximal CSA) and outlet (distal CSA) of the carpal tunnel at 3- 6- and 12-month follow-up. The respective ratios [(CSA postoperatively/CSA preoperatively) × 100] were calculated and correlated with distal motor latency (DML) and sensory nerve conduction velocity (SCV). RESULTS: The proximal CSA ratio was 88.9, 84.5, and 78.4 % at 3-, 6-, and 12-month follow-up, respectively. Each value was significantly lower than that before surgery. The distal CSA ratio was 104.3, 99.1, and 91.8 % at 3-, 6-, and 12-month follow-up, respectively. The values were not significantly different compared to preoperative values. CONCLUSIONS: The proximal CSA of the median nerve decreased continuously over the time after CTR while the distal CSA increased up to 3 months before it decreased continuously, too.

Platelet-Rich Plasma Modulates Actions on Articular Cartilage Lubrication and Regeneration.

Osteoarthritis (OA) is characterized by articular cartilage degeneration in the joints and results in pain, swelling, stiffness, muscle atrophy, and attendant functional disability. The progression of OA cannot be prevented by drugs. Current treatments for OA focus on symptomatic relief of pain. Recently, platelet-rich plasma (PRP) injection has attracted much attention for modulating articular cartilage and synovial membrane in OA. Despite the increasing interest in PRP for the treatment of OA, the precise mechanisms underlying the actions of PRP on OA remain unclear. We have reviewed the known actions of PRP in the joint. The in vitro and in vivo evidence is reviewed concerning the potential of the modulation of PRP on normal articular cartilage and OA progression. PRP modulates the repair and regeneration of damaged articular cartilage in the joints and delays the degeneration of cartilage by stimulation of mesenchymal stem cell migration, proliferation, and differentiation into articular chondrocytes. In addition to the symptomatic relief, PRP is a biological response modifier of inflammatory nuclear factor-κB signaling pathway and PRP reduces the pain by decreasing inflammation and angiogenesis of the synovial membrane where pain receptors are localized. PRP has the therapeutic potential not only to promote tissue regeneration, but also to contribute to articular cartilage lubrication by decreasing the friction coefficient and minimizing wear. Although further refinements and improvements are needed in standardized PRP preparations, PRP may modulate regeneration of articular cartilage and retards the progression of OA by stimulating cell migration, proliferation, differentiation of progenitor/stem cells, joint homeostasis, and joint lubrication.

Can Platelet-Rich Plasma Protect Rat Achilles Tendons From the Deleterious Effects of Triamcinolone Acetonide?

BACKGROUND: Triamcinolone acetonide (TA) injections are widely used for tendinitis but have deleterious effects, including tendon degeneration or tendon rupture. PURPOSE: To investigate whether adding platelet-rich plasma (PRP), a blood fraction that participates in tissue repair processes, to TA can prevent its deleterious effects. STUDY DESIGN: Controlled laboratory study. METHODS: Rat Achilles tendons were injected with TA, TA + PRP, PRP alone, or saline (control). Biomechanical testing and histological analyses were performed on Achilles tendons 1 week after injections. RESULTS: The maximum failure loads in the control, TA, TA + PRP, and PRP groups were 31.7 ± 2.3, 19.0 ± 3.6, 31.0 ± 7.1, and 30.2 ± 6.8 N, respectively. The tendon stiffness in the control, TA, TA + PRP, and PRP groups was 12.1 ± 1.8, 7.5 ± 1.8, 11.0 ± 2.8, and 11.3 ± 2.5 N/mm, respectively. The maximum failure load and stiffness were significantly lower in the TA group compared with the other 3 groups. There was no significant difference between the TA + PRP and control groups. Cell invasions, vacuolation, collagen attenuation, and increased type III collagen expression were histologically observed in the TA group; however, these changes were prevented by the simultaneous administration of PRP. CONCLUSION: Administering PRP may prevent deleterious effects caused by TA; therefore, PRP may be used as a protective agent in clinical situations. CLINICAL RELEVANCE: PRP can be useful as a protective agent for sports injury patients receiving local corticosteroid injections.

Treatment and Diagnosis of Panner's Disease. A Report of Three Cases.

Avascular necrosis of the humeral capitellum (Panner's disease), a relatively rare disorder in the juvenile. We diagnosed three patients using radiographs and magnetic resonance imaging, who were previously misdiagnosed with osteochondritis dissecans of the humeral capitellum. All patients were successfully treated by restriction of sports activities using the upper extremities. It is often difficult to distinguish Panner's disease from osteochondritis dissecans of the humeral capitellum. Panner's disease has been reported to occur in boys between 7 and 10 years old, which is younger than susceptible age of osteochondritis dissecans. In MRI, low intensity area in the ossification center of the humeral capitellum in T1-weighted image is useful findings for diagnosis. For the treatment, the conservative treatment has been recommended in the early stage of Panner's disease, while surgical intervention is required in some cases of osteochondritis dissecans.

Carpal Tunnel Syndrome Caused by Tumoral Calcinosis.

We present a case of carpal tunnel syndrome caused by systemic tumoral calcinosis. A 54-year-old woman experienced hand numbness that persisted for nine months. She had no family history or medical problem. A plain radiograph of her right wrist showed a calcified mass on the volar side of the wrist joint. The patient also experienced pain in her contralateral wrist joint and both right and left shoulders, which had calcification on radiography around the joint. Her condition was diagnosed as carpal tunnel syndrome caused by systemic tumoral calcinosis and a resection biopsy was performed. Histopathological analysis of the biopsied specimen showed basophile deposition inside the fibrous connective tissue. At 14 months after the treatment, she no longer had pain or numbness in her fingers and there was no recurrence of the mass. This patient's condition is considered as a case of nonfamilial, systemic primary tumoral calcinosis. Since incomplete resection leads to a recurrence of the lesion, a follow-up radiography examination is needed to monitor symptom recurrence.

Application of Pain Quantitative Analysis Device for Assessment of Postoperative Pain after Arthroscopic Rotator Cuff Repair.

PURPOSE: The PainVision™ system was recently developed for quantitative pain assessment. Here, we used this system to evaluate the effect of plexus brachialis block on postoperative pain after arthroscopic rotator cuff repair. METHODS: Fifty-five patients who underwent arthroscopic rotator cuff repair were included in this study. First 26 cases received no plexus brachialis block (control group), and the next 29 cases received the plexus brachialis block before surgery (block group). Patients completed the visual analog scale at 4, 8, 16, and 24 hours after surgery, and the intensity of postoperative pain was assessed with PainVision™ at 16 hours. The postoperative use of non-steroidal anti-inflammatory agents was also recorded. RESULTS: The pain intensity at 16 hours after surgery assessed by PainVision™ was significantly lower in the block group than in the control group (block, 252.0 ± 47.8, control, 489.0 ± 89.1, P < 0.05). However, there were no differences in the VAS values at 16 hours between the 2 groups (block, 4.3 ± 0.6, control, 5.7 ± 0.4, P = N.S.). The pain intensity and VAS at 16 hours after surgery were highly correlated (r = 0.59, P = 0.006 in the block group and r = 0.62, P = 0.003 in the control group). The effect size of the assessment by PainVision™ was bigger than that of VAS (r=0.31 in VAS and 0.51 in Pain vision). CONCLUSION: The PainVision™ system could be useful to evaluate postoperative pain because it enables the quantification and comparison of pain intensity independent of individual pain thresholds.

Regeneration of Articular Cartilage Surface: Morphogens, Cells, and Extracellular Matrix Scaffolds.

The articular cartilage is a well-organized tissue for smooth and friction-free joint movement for locomotion in animals and humans. Adult articular cartilage has a very low self-regeneration capacity due to its avascular nature. The regeneration of articular cartilage surface is critical to prevent the progression to osteoarthritis (OA). Although various joint resurfacing procedures in experimental articular cartilage defects have been developed, no standardized clinical protocol has yet been established. The three critical ingredients for tissue regeneration are morphogens and growth factors, cells, and scaffolds. The concepts based on the regeneration triad have been extensively investigated in animal models. However, these studies in animal models have demonstrated variable results and outcomes. An optimal animal model must precisely mimic and model the sequence of events in articular cartilage regeneration in human. In this article, the progress and remaining challenges in articular cartilage regeneration in animal models are reviewed. The role of individual morphogens and growth factors in cartilage regeneration has been investigated. In normal articular cartilage homeostasis, morphogens and growth factors function sequentially in tissue regeneration. Mesenchymal stem cell-based repair of articular cartilage defects, performed with or without various growth factors and scaffolds, has been widely attempted in animal models. Stem cells, including embryonic and adult stem cells and induced pluripotent stem cells, have also been reported as attractive cell sources for articular cartilage surface regeneration. Several studies with regard to scaffolds have been advanced, including recent investigations based on nanomaterials, functional mechanocompatible scaffolds, multilayered scaffolds, and extracellular matrix scaffolds for articular cartilage surface regeneration. Continuous refinement of animal models in chondral and osteochondral defects provide opportunities that support further advances in tissue engineering for the optimal articular cartilage surface regeneration.

Stimulation of the superficial zone protein and lubrication in the articular cartilage by human platelet-rich plasma.

BACKGROUND: Platelet-rich plasma (PRP) contains high concentrations of autologous growth factors that originate from platelets. Intra-articular injections of PRP have the potential to ameliorate the symptoms of osteoarthritis in the knee. Superficial zone protein (SZP) is a boundary lubricant in articular cartilage and plays an important role in reducing friction and wear and therefore is critical in cartilage homeostasis. PURPOSE: To determine if PRP influences the production of SZP from human joint-derived cells and to evaluate the lubricating properties of PRP on normal bovine articular cartilage. STUDY DESIGN: Controlled laboratory study. METHODS: Cells were isolated from articular cartilage, synovium, and the anterior cruciate ligament (ACL) from 12 patients undergoing ACL reconstruction. The concentrations of SZP in PRP and culture media were measured by enzyme-linked immunosorbent assay. Cellular proliferation was quantified by determination of cell numbers. The lubrication properties of PRP from healthy volunteers on bovine articular cartilage were investigated using a pin-on-disk tribometer. RESULTS: In general, PRP stimulated proliferation in cells derived from articular cartilage, synovium, and ACL. It also significantly enhanced SZP secretion from synovium- and cartilage-derived cells. An unexpected finding was the presence of SZP in PRP (2.89 ± 1.23 µg/mL before activation and 3.02 ± 1.32 µg/mL after activation). In addition, under boundary mode conditions consisting of high loads and low sliding speeds, nonactivated and thrombin-activated PRP decreased the friction coefficient (µ = 0.012 and µ = 0.015, respectively) compared with saline (µ = 0.047, P < .004) and high molecular weight hyaluronan (µ = 0.080, P < .006). The friction coefficient of the cartilage with PRP was on par with that of synovial fluid. CONCLUSION: PRP significantly stimulates cell proliferation and SZP secretion by articular cartilage and synovium of the human knee joint. Furthermore, PRP contains endogenous SZP and, in a functional bioassay, lubricates bovine articular cartilage explants. CLINICAL RELEVANCE: These findings provide evidence to explain the biochemical and biomechanical mechanisms underlying the efficacy of PRP treatment for osteoarthritis or damage in the knee joint.

Surgical site infection in spinal surgery: a comparative study between 2-octyl-cyanoacrylate and staples for wound closure.

BACKGROUND: Surgical site infection (SSI) after spinal surgery is a devastating complication. Various methods of skin closure are used in spinal surgery, but the optimal skin-closure method remains unclear. A recent report recommended against the use of metal staples for skin closure in orthopedic surgery. 2-Octyl-cyanoacrylate (Dermabond; Ethicon, NJ, USA) has been widely applied for wound closure in various surgeries. In this cohort study, we assessed the rate of SSI in spinal surgery using metal staples and 2-octyl-cyanoacrylate for wound closure. METHODS: This study enrolled 609 consecutive patients undergoing spinal surgery in our hospital. From April 2007 to March 2010 surgical wounds were closed with metal staples (group 1, n = 294). From April 2010 to February 2012 skin closure was performed using 2-octyl-cyanoacrylate (group 2, n = 315). We assessed the rate of SSI using these two different methods of wound closure. Prospective study of the time and cost evaluation of wound closure was performed between two groups. RESULTS: Patients in the 2-octyl-cyanoacrylate group had more risk factors for SSI than those in the metal-staple group. Nonetheless, eight patients in the metal-staple group compared with none in the 2-octyl-cyanoacrylate group acquired SSIs (p < 0.01). The closure of the wound in length of 10 cm with 2-octyl-cyanoacrylate could save 28 s and $13.5. CONCLUSIONS: This study reveals that in spinal surgery, wound closure using 2-octyl-cyanoacrylate was associated with a lower rate of SSI than wound closure with staples. Moreover, the use of 2-octyl-cyanoacrylate has a more time saving effect and cost-effectiveness than the use of staples in wound closure of 10 cm in length.

A new bioabsorbable cotton-textured synthetic polymer scaffold for osteochondral repair.

PURPOSE: We have previously reported that a cylindrical bioabsorbable synthetic polymer scaffold made of poly (DL-lactide-co-glycolide) (PLG) can be used to repair osteochondral defects without using cultured cells in a rabbit model. This cylindrical scaffold has a solid and pre-formed design, which limits its widespread application. Therefore, we created a cotton-textured PLG scaffold, which would be superior to other scaffolds in terms of plastic property and operability. The purpose of the present study was to examine the efficacy of the cotton-textured PLG scaffold in the repair of osteochondral defects. METHODS: Cotton-textured PLG scaffolds were prepared using the electrospinning method and used to repair osteochondral defects produced on the right femoral condyle in 36 rabbits. As a control, the defect was left untreated. The outcomes of repair were examined histologically at postoperative weeks four, eight, and 12. RESULTS: In the untreated control group, the surface of the defect remained concave and the regenerated cartilaginous tissue partially covered the articular surface even at postoperative week 12. In the scaffold group, cartilaginous tissue covered the surface of the defect at postoperative week four, and the surface was smooth and the cartilaginous tissue was well regenerated and integrated with the native cartilage at postoperative week 12. CONCLUSIONS: The cotton-textured PLG scaffold could repair the osteochondral defect with good outcomes similar to those previously reported for the cylindrical scaffold, with its characteristic advantages of better plasticity and operability. We conclude that the cotton-textured PLG scaffold has potential for clinical application in comminuted osteochondral injury.

Induction of chondrogenesis and expression of superficial zone protein in synovial explants with TGF-ß1 and BMP-7.

Superficial zone protein (SZP) functions as a boundary lubricant in articular cartilage and decreases the coefficient of friction. As lubrication of articular cartilage is critical for normal joint function, the ability to secrete SZP at the surface of tissue-engineered cartilage is a prerequisite for optimal lubrication. Synovium-derived mesenchymal stem cells (MSCs) are thought to be an attractive cell source for cartilage regeneration. However, optimization of a three-dimensional environment is necessary for tissue engineering. In this study, we investigated whether synovial explants, which would preserve the physiologic microenvironment for MSCs therein, have the potential of SZP secretion after chondrogenic differentiation by treatment with transforming growth factor-ß1 (TGF-ß1) and bone morphogenetic protein-7 (BMP-7). Immunostaining and enzyme-linked immunosorbent assay analysis demonstrated that synovial explants can synthesize and secrete SZP following chondrogenic differentiation in response to TGF-ß1 and BMP-7. Interestingly, the combined treatment with TGF-ß1 and BMP-7 or treatment first with TGF-ß1 followed by BMP-7 was more effective than other treatment groups in both chondrogenic differentiation and SZP secretion. In conclusion, synovial explants represent not only a superb source of progenitors/stem cells for the regeneration of the surface zone of articular cartilage, but also a useful model system for the in vitro differentiation into mature articular cartilage phenotypes in response to morphogens for tissue engineering of articular cartilage.