Predictive factors associated with failure of nonoperative treatment of superior labrum anterior-posterior tears.

BACKGROUND: Uncertainty remains in the natural course of superior labrum anterior-posterior (SLAP) tears treated conservatively with rehabilitation and activity modification. Our purpose was to evaluate clinical outcomes after nonoperative treatment of type II SLAP tear in young active patients and to identify factors related to negative outcomes. METHODS: We retrospectively reviewed 63 patients who initially underwent nonoperative treatment for isolated type II SLAP tear. Assessments were made at baseline and at 6 months, and telephone survey was used to evaluate the final outcome. All included patients underwent a consistent nonoperative treatment protocol, and patient-specific data on the outcome were assessed. Failure was defined as abandonment of nonoperative management for surgery at any time points, <20-point improvement in American Shoulder and Elbow Surgeons score at final follow-up, or inability to return to activities. RESULTS: At the average follow-up of 21 months, pain relief and function improved significantly (American Shoulder and Elbow Surgeons score, 54.2-86.4; Visual Analog Scale score, 4.6-1.7; P < .05) in 45 patients (71.4%) with successful nonoperative treatment. Eighteen patients (28.5%) were either dissatisfied with treatment or had arthroscopic surgery and were considered a failure group. Multivariate analysis showed that failure of nonoperative treatment is strongly linked with history of trauma, positive compression-rotation test result, and participation in overhead activities (P < .05). CONCLUSIONS: An initial trial of nonoperative management may be considered in young active patients with isolated SLAP tear. Patients with history of trauma, mechanical symptoms, and demand for overhead activities are less likely to succeed.

Comparison of Clinical and Radiologic Results Between Partial Meniscectomy and Refixation of Medial Meniscus Posterior Root Tears: A Minimum 5-Year Follow-up.

PURPOSE: To compare the clinical and radiologic results of partial meniscectomy with those of refixation in patients with medial meniscus posterior root tears (MMPRTs) at a minimum 5-year follow-up. METHODS: Between 2005 and 2009, patients with MMPRTs who had been followed up for at least 5 years after a partial meniscectomy (group M, n = 20) or pullout repair (group R, n = 37) were recruited. The mean follow-up duration was 67.5 months in group M and 72.0 months in group R. Clinical assessments, including the Lysholm score and International Knee Documentation Committee (IKDC) Subjective Knee Form score, and radiographic assessments, including the Kellgren-Lawrence (K-L) grade and medial joint space width, were evaluated preoperatively and at final follow-up. We compared the preoperative results with the final results in each group, and we compared the final results of groups M and R. Five-year survival rates were also evaluated. RESULTS: The mean Lysholm score (P = .039) and IKDC score (P = .037) improved significantly. However, the width of the medial joint space (P < .001) and K-L grade (P < .001) worsened significantly in both groups. When we compared the final results, group R had significantly better Lysholm scores (P = .002) and IKDC scores (P < .001) than group M. Group R showed less K-L grade progression (P = .005) and less medial joint space narrowing (P < .001) than group M. The rate of conversion to total knee arthroplasty was 35% in group M, whereas there was no conversion to total knee arthroplasty in group R. The 5-year survival rates in groups M and R were 75% and 100%, respectively (P < .001). CONCLUSIONS: For MMPRTs, refixation was more effective than partial meniscectomy in terms of the clinical and radiologic outcomes and survival for at least 5 years' follow-up. Refixation slowed the progression of arthritic changes compared with partial meniscectomy, although it did not prevent the progression of arthrosis completely. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Traumatic posterior root tear of the medial meniscus in patients with severe medial instability of the knee.

PURPOSE: To examine the incidence and diagnostic rate of traumatic medial meniscus posterior root tear associated with severe medial instability and to evaluate the effectiveness of pullout repair. METHODS: From 2007 to 2011, 51 patients who underwent operation due to multiple ligament injuries including medial collateral ligament rupture were reviewed retrospectively. The International Knee Documentation Committee (IKDC) subjective and Lysholm score were evaluated pre- and postoperatively. Postoperative magnetic resonance imaging (MRI) was performed, and if indicated, a second-look arthroscopic examination was conducted. RESULTS: Fourteen out of 51 patients were associated with severe medial instability. Seven patients were diagnosed with traumatic medial meniscus posterior root tear and underwent arthroscopic pullout repair. Five of them were missed at initial diagnosis using MRI. In seven patients, the mean Lysholm and IKDC subjective scores improved from 74.6 ± 10.3 and 47.6 ± 7.3 to 93.0 ± 3.7 and 91.6 ± 2.6, respectively. All showed complete healing of meniscus root on follow-up MRI and second-look arthroscopy. CONCLUSION: Medial meniscus posterior root tear may occur in severe medial instability from trauma. It is a common mistake that surgeons may not notice on the diagnosis of those injuries using MRI. Therefore, a high index of suspicion is required for the diagnosis of medial meniscus posterior root tear in this type of injuries. The traumatic medial meniscus posterior root tear could be healed successfully using arthroscopic pullout repair technique. CLINICAL RELEVANCE: The possibility of the medial meniscus posterior root tear should be considered in severe medial instability and arthroscopic pullout repair can be an effective option for treatment. LEVEL OF EVIDENCE: Case series with no comparison group, Level IV.

Microfabrication of microchannels for fuel cell plates.

Portable electronic devices such as notebook computers, PDAs, cellular phones, etc., are being widely used, and they increasingly need cheap, efficient, and lightweight power sources. Fuel cells have been proposed as possible power sources to address issues that involve energy production and the environment. In particular, a small type of fuel-cell system is known to be suitable for portable electronic devices. The development of micro fuel cell systems can be achieved by the application of microchannel technology. In this study, the conventional method of chemical etching and the mechanical machining method of micro end milling were used for the microfabrication of microchannel for fuel cell separators. The two methods were compared in terms of their performance in the fabrication with regards to dimensional errors, flatness, straightness, and surface roughness. Following microchannel fabrication, the powder blasting technique is introduced to improve the coating performance of the catalyst on the surface of the microchannel. Experimental results show that end milling can remarkably increase the fabrication performance and that surface treatment by powder blasting can improve the performance of catalyst coating.

Biportal endoscopic versus microscopic lumbar decompressive laminectomy in patients with spinal stenosis: a randomized controlled trial.

BACKGROUND CONTEXT: Biportal endoscopic decompressive laminectomy is a widely performed procedure and shows acceptable clinical outcomes. However, the evidence regarding the advantages of biportal endoscopic surgery is weak, a randomized controlled trial is therefore warranted. PURPOSE: To compare the clinical efficacies of biportal endoscopic and microscopic decompressive laminectomy in patients with lumbar spinal stenosis. STUDY DESIGN: Randomized controlled trial. PATIENT SAMPLE: Sixty-four participants suffering from low back and leg pain with single-level lumbar spinal stenosis who required decompressive laminectomy. OUTCOME MEASURES: Outcomes were assessed with the use of patient-reported outcome measures, visual analog scale (VAS) score for low back and lower extremity radiating pain, Oswestry disability index (ODI), European Quality of Life-5 Dimensions (EQ-5D) score, and painDETECT for neuropathic pain. Surgery-related outcomes including operation time, length of hospital stay, postoperative drainage, and serum creatine phosphokinase were evaluated. Perioperative (<30 days) and late (1-12 months) complications were also noted. METHODS: All participants were randomly assigned in a 1:1 ratio to undergo biportal endoscopic or microscopic decompressive laminectomy. The primary outcome was the ODI score at 12 months after surgery based on a modified intention-to-treat strategy. The secondary outcomes included VAS score for low back and lower extremity radiating pain, ODI scores, EQ-5D score, and painDETECT score. There were no sources of funding and no conflicts of interest associated with this study. RESULTS: There was no significant difference between groups in the mean ODI score at 12 months after surgery (30 in the microscopy vs. 29 in the biportal endoscopy group, p=.635). There were also no significant differences in low back and lower extremity pain VAS scores, ODI, EQ-5D scores, and painDETECT scores at the 3-, 6-, or 12-month follow-up. Operation time, length of hospital stay, serum creatine phosphokinase, and perioperative complications, such as durotomies and symptomatic hematoma, showed no significant differences between the groups; however, one participant underwent additional revision surgery 9 months after the index surgery in the microscopy group. CONCLUSIONS: Despite the study design limitation of relatively short duration of follow-up, this trial suggests that biportal endoscopic decompressive laminectomy is an alternative to and offers similar clinical outcomes as microscopic open surgery in patients with symptomatic lumbar spinal stenosis.

Micro Fluidic Channel Machining on Fused Silica Glass Using Powder Blasting.

In this study, micro fluid channels are machined on fused silica glass via powder blasting, a mechanical etching process, and the machining characteristics of the channels are experimentally evaluated. In the process, material removal is performed by the collision of micro abrasives injected by highly compressed air on to the target surface. This approach can be characterized as an integration of brittle mode machining based on micro crack propagation. Fused silica glass, a high purity synthetic amorphous silicon dioxide, is selected as a workpiece material. It has a very low thermal expansion coefficient and excellent optical qualities and exceptional transmittance over a wide spectral range, especially in the ultraviolet range. The powder blasting process parameters affecting the machined results are injection pressure, abrasive particle size and density, stand-off distance, number of nozzle scanning, and shape/size of the required patterns. In this study, the influence of the number of nozzle scanning, abrasive particle size, and pattern size on the formation of micro channels is investigated. Machined shapes and surface roughness are measured using a 3-dimensional vision profiler and the results are discussed.

Micro Dot Patterning on the Light Guide Panel Using Powder Blasting.

This study is to develop a micromachining technology for a light guidepanel(LGP) mold, whereby micro dot patterns are formed on a LGP surface by a singleinjection process instead of existing screen printing processes. The micro powder blastingtechnique is applied to form micro dot patterns on the LGP mold surface. The optimalconditions for masking, laminating, exposure, and developing processes to form the microdot patterns are first experimentally investigated. A LGP mold with masked micro patternsis then machined using the micro powder blasting method and the machinability of themicro dot patterns is verified. A prototype LGP is test- injected using the developed LGPmold and a shape analysis of the patterns and performance testing of the injected LGP arecarried out. As an additional approach, matte finishing, a special surface treatment method,is applied to the mold surface to improve the light diffusion characteristics, uniformity andbrightness of the LGP. The results of this study show that the applied powder blastingmethod can be successfully used to manufacture LGPs with micro patterns by just singleinjection using the developed mold and thereby replace existing screen printing methods.

Biomechanical Analysis of a Novel Wedge Locking Plate in a Porcine Tibial Model.

BACKGROUND: The purpose of this study was to analyze biomechanical properties of a novel wedge locking plate in medial open wedge high tibial osteotomy (OWHTO) in a porcine tibial model. METHODS: A uniform 8-mm OWHTO was performed in 12 porcine tibiae. Six of them were subsequently fixed with the plate without a wedge, whereas the other 6 were additionally reinforced with a metal wedge of 8 mm. Biomechanical properties (stiffness, displacement of the osteotomy gap, and failure load) were evaluated under axial load. The different modes of failure were also investigated. RESULTS: The plate showed an axial stiffness of 2,457 ± 450 N/mm with a wedge and 1,969 ± 874 N/mm without a wedge. The maximum failure load was 5,380 ± 952 N with a wedge and 4,354 ± 607 N without a wedge. The plate with a wedge had a significantly greater failure load and significantly less displacement of medial gap at failure than that without a wedge (p = 0.041 and p = 0.002, respectively). The axial stiffness was not different between the two types of fixation. Most failures were caused by lateral cortex breakage and there was no implant failure. CONCLUSIONS: The novel wedge locking plate showed excellent biomechanical properties and an additional wedge provided significant improvement. This plate can be a good fixation method for OWHTO.