From materials to clinical use: advances in 3D-printed scaffolds for cartilage tissue engineering.

Osteoarthritis caused by articular cartilage defects is a particularly common orthopedic disease that can involve the entire joint, causing great pain to its sufferers. A global patient population of approximately 250 million people has an increasing demand for new therapies with excellent results, and tissue engineering scaffolds have been proposed as a potential strategy for the repair and reconstruction of cartilage defects. The precise control and high flexibility of 3D printing provide a platform for subversive innovation. In this perspective, cartilage tissue engineering (CTE) scaffolds manufactured using different biomaterials are summarized from the perspective of 3D printing strategies, the bionic structure strategies and special functional designs are classified and discussed, and the advantages and limitations of these CTE scaffold preparation strategies are analyzed in detail. Finally, the application prospect and challenges of 3D printed CTE scaffolds are discussed, providing enlightening insights for their current research.

Electromigration Analysis for Interconnects Using Improved Graph Convolutional Network with Edge Feature Aggregation.

Electromigration (EM) is a critical reliability issue in integrated circuits and is becoming increasingly significant as fabrication technology nodes continue to advance. The analysis of the hydrostatic stress, which is paramount in electromigration studies, typically involves solving complex physical equations (partial differential equations, or PDEs in this case), which is time consuming, inefficient and not practical for full-chip EM analysis. In this paper, a novel approach is proposed, conceptualizing circuit interconnect trees as a graph within a graph neural network framework. Using finite element solution software, ground truth hydrostatic stress values were obtained to construct a dataset of interconnected trees with hydrostatic stress values for each node. An improved Graph Convolutional Network (GCN) augmented with edge feature aggregation and attention mechanism was then trained employing the dataset, yielding a model capable of predicting hydrostatic stress values for nodes in an interconnect tree. The results show that our model demonstrated a 15% improvement in the Root Mean Square Error (RMSE) compared to the original GCN model and improved the solution speed greatly compared to traditional finite element software.

Gait Training of Healthy Older Adults in a Sitting Position using the Wearable Robot to Assist Arm-swing Rhythm, WALK-MATE ROBOT.

Although various walking training robots have been developed and their effectiveness has been recognised, operating these robots requires the implementation of safety measures to avoid the risk of falling. This study aimed to confirm whether arm swing rhythm training in the sitting position using an arm swing rhythm-assisted robot, WMR, improved subsequent walking. Healthy older adults (N = 20) performed arm swing rhythm training in a sitting position for 1 min × three times while being presented with tactile stimulation synchronised with the arm swing rhythm from a robot. An increase in walking performance was observed with increases in stride length and speed. In addition, the stabilisation of the gait pattern was observed, with a decrease in the proportion of the double-foot support phase and an increase in the proportion of the swing phase in one gait cycle. These results suggest that arm swing rhythm training in a sitting position using WMR improves gait in older adults. This will lead to the realisation of safe and low-cost robot-based walking training in sitting position.

[Case-control study on poking closed reduction cannulated screw fixation and small incision reduction plate fixation for the treatment of calcaneal fractures].

OBJECTIVE: To compare poking closed reduction cannulated screw fixation and small incision reduction plate fixation in treating calcaneal fractures. METHODS: Clinical data of 98 patients with calcaneal fractures were retrospectively analyzed from June 2015 and June 2018. According to fracture classification and treatment methods, the patients were divided into poking closed reduction cannulated screw fixation (group A) and small incision reduction plate fixation(group B). In group A, there were 50 patients, including 32 males and 18 females with an average of (32.6±6.7) years old; 30 patients were classified to type Sanders II-III and 20 patients were type Sanders IV; treated with poking closed reduction cannulated screw fixation. While in group B, there were 48 patients, including 30 males and 18 females with an average of (31.9±7.2) years old; 28 patients were classified to type Sanders II-III and 20 patients were type Sanders IV; treated with small incision reduction plate fixation. Böhler angle, Gissane angle and AOFAS scores were compared between two groups before operation and 1 month, 1 year after operation. RESULTS: All patients were followed up for 13 to 24 months with an average of (14.6±6.3) months. Böhler angle, Gissane angles and AOFAS score between two groups were improved at different degrees after operation. For Sanders II and III patients, there were no statistical differences in Böhler angle, Gissane angle between two groups before operation, 1 month and 1 year after operation; and there was no differences in AOFAS score between two groups at 1 year after operation. For Sanders IV patients, Böhler angle [(35.40±1.85)°, (35.15±1.90)°] and Gissane angles[(127.80±5.49)°, (127.00±3.06)°] in group B were higher than that of group A[(27.85±3.42) °, (27.25±1.80)° and (118.00±4.13)°, (117.50±5.04)°] at 1 month and 1 year after operation(P<0.05); Böhler angle and Gissane angle at 1 month and 1 year after operation between two groups were improved higher than before operation(P<0.05); AOFAS score in group B (91.00±5.46) was higher than that of group A (84.50±4.64) (P<0.05). CONCLUSIONS: For Sanders II-III calcaneal fractures, the two treatment methods have the equivalent effect. While for Sanders IV patients, small incision reduction plate fixation has better reduction, stable fixation and could improve foot function compared with poking closed reduction cannulated screw fixation.

Risedronate reduces postoperative bone resorption after cementless total hip arthroplasty: A systematic review and meta-analysis.

OBJECTIVE: To examine the effects of risedronate for reducing periprosthetic bone loss after total hip arthroplasty (THA). METHODS: Two reviewers performed an electronic literature search for randomized controlled trial (RCTs) evaluating the risedronate in the management of periprosthetic bone loss after primary THA. The electronic databases include PubMed, Medline, Embase, Web of Science and the Cochrane Library from inception to January 2018. We assessed the risk of bias using the Cochrane risk-of-bias tool. STATA 14.0 was used to perform the meta-analysis. RESULTS: Four RCTs were included in our study. Current meta-analysis indicated that postoperative reduciton of periprosthetic BMD in the risedronate group was significantly lower than that in the placebo group in zones 1, 2, 3, 4, 6, and 7. There was no increased risk of adverse effects. CONCLUSION: The administration of risedronate was associates with a significantly improved periprosthetic BMD after primary THA. No increased risk of adverse events were observed. Higher quality RCTs are still required for further research.

[Clinical outcomes of total hip arthroplasty using Wagner SL revision stem in femoral intertrochanteric fractures for patients with old fracture or painful arthritis before injury].

OBJECTIVE: To retrospectively study the clinical results of total hip arthroplasty(THA) using Wagner SL revision stem for patients with femoral intertrochanteric fracture. METHODS: From 2006 January to 2009 December, 29 consecutive patients with femoral intertrochanteric fractures were performed THA using Wagner SL revision stem and intertrochanteric reconstruction, including 18 males and 11 females with an average age of 49 years old ranging from 43 to 58. Among them, 8 cases were oboslete femoral intertrochanteric fractures and 21 cases were the intertrochanteric fractures with painful arthritis before injuries. After the operation, the follow-up results were evaluated with clinical and radiographic criteria. The clinical follow-up results were evaluated by Harris score, limb length discrepancy, ROM of hips and the strength of the hip abductor. The X-ray imaging follow-up results were evaluated by periprosthetic osteolysis, prosthesis loosening and radiolucent. RESULTS: All the operations were successfully completed without serious complications associated with THA. Twenty-nine cases were followed up for a mean duration of 8.2 years (ranged, 6 to 10). There was no acceptable thigh pain. The first time walk after operation, 8 patients with oboslete intertrochanteric fracture complained the surgical sides were longer, with the passage of time, the complaint significantly reduced. At 3 months after operation, X-ray films of 21 cases showed intertrochanteric fractures healed well who had painful arthritis before injuries. An average of 6 months after operation (ranged, 3 to 8), X-ray films of 8 cases of oboslete intertrochanteric fracture showed that the bone graft and trochanter with obvious callus connection. There were no obvious prosthesis subsidence on X-ray film at the final follow-up. The recovery of hip movement range was satisfactory, no hip abduction strength was weak. More than 6 years after the operation, according to the Harris scoring evaluation of hip joint, the result was excellent in 18 cases, good in 9 cases, general in 2 cases. CONCLUSIONS: The clinical results of total hip arthroplasty using Wagner SL revision stem for patient with femoral intertrochanteric fracture is a reliable method, intertrochanteric reconstruction not only makes for prosthesis and joint stability, but also increases bone reserve.

[EFFECTIVENESS OF COMBINED TENODESIS FOR PROXIMAL LESIONS OF BICEPS TENDON WITH MASSIVE ROTATOR CUFF TEAR BY ARTHROSCOPY].

OBJECTIVE: To evaluate the effectiveness of the combined tenodesis for proximal lesions of biceps tendon with massive rotator cuff tear by arthroscopy. METHODS: Between January 2011 and June 2013, 48 patients with massive rotator cuff tear and proximal lesions of biceps tendon underwent combined tenodesis under arthroscopy, and the clinical data were retrospectively analyzed. Of 48 cases, 22 were male and 26 were female with an average age of 46 years (range, 35-59 years); 12 cases had clear history of trauma. The disease duration ranged from 1 to 57 months (mean, 4.6 months). All cases suffered from moderate to severe shoulder pain, the strength and the range of motion (ROM) declined when compared with those of the other side. According to Goutallier classification standard, 3 cases were rated as grade 0, 18 cases as grade 1, and 27 cases as grade 2. The operation time and complication were recorded. The visual analogue scale (VAS) score, ROM, the strength of flexed elevation and elbow flexion, Constant-Murley score, University of California Los Angeles (UCLA) score, American Shoulder and Elbow Surgeons (ASES) score, Mayo elbow performance score (MEPS) were used to evaluate the effectiveness. RESULTS: The operations were performed successfully, and incisions healed primarily. The operation time was 120-160 minutes (mean, 135 minutes). One case had shoulder joint swelling with wound bleeding, which was cured after proper treatment. All 48 patients were followed up 12-18 months (mean, 13.9 months). The results of MRI showed good healing of tendon at 6 months after operation. When compared with preoperative values, VAS score was significantly decreased (P < 0.05); the ROM in forward flexion, external rotation, and internal rotation, and the strength of flexed elevation were significantly increased (P < 0.05); and ASES score, Constant- Murley score, and UCLA score were significantly improved at 12 months after operation (P < 0.05). No significant difference was observed in MEPS score and elbow flexion strength (P > 0.05). CONCLUSION: The technique of combined tenodesis under arthroscopy can obtain satisfactory clinical outcomes in treating proximal lesions of biceps tendon with massive rotator cuff tear.

[MRI ainalysis of the pseudo-tears of the lateral meniscus of the knee and its clinical significance].

OBJECTIVE: To determine the mechanism of pseudo-tears of the lateral meniscus caused by the transverse geniculate ligament (TL) and the miniscofemoral ligament(MFL) and to investigate a method to differentiate pseudo-tears from true tear of the lateral meniscus. METHODS: Form June 2012 to February 2014, MR examinations of 72 knees (44 left knees and 28 right knees) without tear of the lateral meniscus verified by arthroscopy were performed in the sagittal and coronal plane. There were 41 males and 31 females in the group, with an average age of 33.7 years old (ranged from 25 to 61). The MR appearance of the TL and the MFL was carefully observed. RESULTS: There existed fatty tissue in the gap between the TL and the anterior horn of the lateral meniscus and its central tendinous attachment. On the sagittal images, the fatty tissue formed a linear high-signal cleft between the TL and the anterior horn of the lateral meniscus. This might be mistaken as an oblique tear within the anterior horn of the lateral meniscus. It was called as pseudo-tears of the anterior horn of the lateral meniscus. In sagittal plane, the MFL was identified as a circle-like or short stick-like area of low signal intensity anterior or posterior to the posterior cruciateligament. Nevertheless, a belt-shaped area of low signal intensity from the posterior horn of the lateral meniscus to lateral facet of the medial femoral condyle was identified in the coronal plane. A linear area of high signal intensity between the MFL and the lateral meniscus was found in sagittal plane, which might be mistaken as an oblique tear within the posterior horn of the lateral meniscus. It was called pseudo-tears of the posterior horn of the lateral meniscus. The occurrence rate of the TL was 34.7% (25/72). The prevaleribe of pseudo-tears of the anterior horn of the lateral meniscus was 18 cases. The shape of the anterior horn of the lateral meniscus was regular, and the course of the pseudo-tears cleft was oblique. The occurrence rate of the MFL was 73.6% (53/72), which included the anterior MFL 23.6% (17/72), the posterior MFL 70.8% (51/72) and the two ligaments coexisted 16.7% (12/72). The prevalence of pseudo-tears of the posterior horn of the lateral meniscus was 25 cases. All observed pseudo-tears had either in posteroinferiorly oblique direction (19/25) or in vertical direction (6/25). CONCLUSION: Based on the location and direction of pseudo-tears and observation in the continuous sagittal plane and the coronal plane, pseudo-tears is easily differentiated from the true tear of the lateral meniscus

[Diagnostic value of 3D-indirect magnetic resonance arthrography in detecting meniscal tears of the knees].

OBJECTIVE: To explore the diagnostic value of 3D-indirectmagnetic resonance (MR) arthrography in detecting meniscustears of the knees. METHODS: Form January 2013 to January 2014, routine plain MR of the knees followed by the 3D-indirect MR arthrography was performed in 42 patients with suspected meniscal tears clinically. There were 31 males and 11 females, with an average age of 38.4 years old (ranged, 21 to 67 years old). The duration of the course ranged from 2 h to 15 d. The clinical symptom was knee pain. All the patients got subsequently arthroscopic examination or operation. The sensitivity and specificity of routine plain MR and 3D-indirect MR arthrography were compared based on the results of arthroscopic examination or operation. RESULTS: The signal intensity in the area of meniscal tears on image of 3D-indirect MR arthrography was obviously higher than that of routine plain MR. The sensitivity of 3D-indirect MR arthrography was 85.79% (87/102), while the routine plain MR was 52.94% (54/102), and the specificity improved from 67.78%(61/90) to 86.67%(78/90). The difference was statistically significant (χ2 = 25.90, P < 0.01; χ2 = 9.13, P < 0.01). CONCLUSION: In comparison with the routine plain MR findings, 3D-indirect MR arthrography demonstrates meniscus tears of the knee with the better sensitivity and specificity.