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The water channel aquaporin 4 (AQP4) regulates the flux of water across the cell membrane, maintaining cellular homeostasis. Since AQP4 is enriched in the sarcolemma of skeletal muscle, a functional defect in AQP4 may cause skeletal muscle dysfunction. To investigate a novel mechanism underlying skeletal muscle atrophy, we examined AQP4 expression and its regulation in muscle using the rotator cuff tear (RCT) model. Human and mouse AQP4 expression was significantly decreased in atrophied muscle resulting from RCT. The size and the number of myotubes were reduced following AQP4 knockdown. Atrogin 1-mediated ubiquitination of AQP4 was verified with an ubiquitination assay after immunoprecipitation of AQP4 with an anti-AQP4 antibody. In this study, we identified high mobility group box 1 (HMGB1) as a potent upstream regulator of atrogin 1 expression. Atrogin 1 expression was increased by recombinant mouse HMGB1 protein, and the HMGB1-induced atrogin 1 expression was mediated via NF-κB signaling. Our study suggests that loss of AQP4 appears to be involved in myocyte shrinkage after RCT, and its degradation is mediated by atrogin 1-dependent ubiquitination. HMGB1, in its function as a signaling molecule upstream of the ubiquitin ligase atrogin 1, was found to be a novel regulator of muscle atrophy.

Purpose To evaluate the surgical methods according to the status of tunnels at the time of revision anterior cruciate ligament reconstruction (ACLR) and to evaluate clinical outcomes of revision ACLR in patients who underwent primary ACLR with the anatomic 4-tunnel double-bundle (DB) technique. Methods A total of 487 patients who underwent primary anatomic DB ACLR from April 2010 to July 2016 were retrospectively reviewed, and among those knees, the patients who underwent revision ACLR were included in the study. The patients with concomitant posterior cruciate ligament injuries were excluded. Forty patients (40 knees) were identified and enrolled. The surgical methods were reviewed. The range of motion, objective laxity using KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score after revision ACLR were compared with those after primary ACLR in the same patient using paired t-test with Bonferroni correction. Results The timing of reinjury after primary ACLR and mean interval between primary and revision ACLR were 18 months (range 1.5-80 months) and 24 months (range 4-82 months), respectively. Among 40 patients, 38 patients (95%) underwent 1-stage revision with the DB technique using pre-existing tunnels without compromised positioning of the grafts, and the other 2 patients (5%) underwent 2-stage revision. The postrevision range of motion, KT-2000, Lysholm score, Hospital for Special Surgery score, International Knee Documentation Committee subjective score, and Tegner score were 137 ± 7°, 2.4 ± 1.2 mm, 91.4 ± 5.8, 98.9 ± 2.2, 78.6 ± 11.5, and 5.5 ± 1.2, respectively, and did not show any differences from those after primary ACLR. Conclusions In the revision setting after primary anatomic DB ACLR, most of the cases could be managed with 1-stage revision with DB technique using pre-existing tunnels, and the objective laxity and clinical scores after revision DB ACLR were comparable with those after primary DB ACLR. Level of Evidence Case series, Level IV.

Background Only limited data are available regarding postural stability between anterior cruciate ligament (ACL)-injured patients with medial meniscus (MM) tear and those with lateral meniscus (LM) tear. The purpose of this study was to compare preoperative postural stability for both involved and uninvolved knees in ACL rupture combined with MM and LM tears. It was hypothesized that there would be a significant difference in postural stability between these two groups. Methods Ninety-three ACL-injured patients (53 combined with MM tears vs. 40 combined with LM tears) were included. Static and dynamic postural stability were evaluated with the overall stability index (OSI), anterior–posterior stability index (APSI), and medial–lateral stability index (MLSI) using stabilometry. Knee muscle strength was evaluated using an isokinetic testing device. Results In the static postural stability test, none of the stability indices showed significant differences between the two groups for both knees (p > 0.05). In the dynamic postural stability test for involved side knees, the OSI and APSI were significantly higher in the LM tear group compared to the MM tear group (OSI: 2.0 ± 0.8 vs. 1.6 ± 0.5, p = 0.001; APSI: 1.5 ± 0.6 vs. 1.3 ± 0.5, p = 0.023), but not the MLSI (p > 0.05). In the static and dynamic postural stability tests in each group, there were no significant differences between the involved and uninvolved side knees (p > 0.05). There was no significant difference in the knee muscle strength between the two groups (p > 0.05). All postural stability showed no significant correlation with knee muscle strength (p > 0.05). Conclusion Dynamic postural stability was poorer in patients with ACL rupture combined with LM tear than in those with MM tear. Therefore, close monitoring for postural stability would be necessary during preoperative and postoperative rehabilitation, especially for patients with ACL rupture combined with LM tear. Level of evidence: Level III

With surgical modifications reflecting plate design differences of the specific rigid locking plate adding a metal wedge, uniplane high tibial osteotomy (HTO) has fewer lateral-hinge fractures and fewer plate irritations than biplane HTO. Uniplane HTO with a rigid locking plate adding a metal wedge was compared with biplane HTO with a rigid locking plate including a proximal D-hole. For comparison, the HTO patients’ medical records and radiological results in a single institution were retrospectively reviewed. The Oxford knee score 2 years post-operation, CT scan at post-operative day 2 and serial standing long-bone scanography were reviewed to evaluate clinical outcome and radiological results, including the incidence of lateral-hinge fracture, plate irritation and correction loss to varus alignment. A total of 103 knees, including 59 uniplane HTO and 44 biplane HTO, were enrolled. The Oxford scores were 38.1 ± 7.8 in the uniplane group and 35.9 ± 8.3 in the biplane group (ns). On CT scans, more lateral-hinge fractures developed in the biplane group, and seven knees (12%) of the uniplane group and 12 knees (27%) of the biplane group had Takeuchi type I stable hinge fracture (p

Background Stable water dynamics during endoscopic spine surgery improves the surgeon's comfort and patient's outcomes. We aimed to measure the water dynamics during spinal surgery and identify the factors that facilitate stable water dynamics. Methods This open-label, prospective, proficiency-matched, in vivo study included patients with single-level degenerative spinal disease. After assessing their heights and balancing the matched instrument, we measured the irrigation fluid pressure in various situations. We performed multiple regression analysis based on odds ratio (OR), confidence interval (CI), and relationships (proficiency-matched) with possible instrumental and physical characteristics. The instrumental factors were the presence and length of a rigid cannulation, and the physical characteristics were body mass index (body mass index [BMI]), skin-to-dura depth, height (interaction with BMI), and body weight (interaction with BMI). Results Of the 36 patients, 29 were included. The mean pressure of the operation cavity was 16.66 ± 9.12 cm H2O (12.25 ± 6.71 mm Hg). Water pressure with the rigid cannulation (9.41 ± 2.94 cm H2O [6.92 ± 2.16 mm Hg]) was significantly lower than that without cannulation (23.43 ± 7.57 cm H2O [17.26 ± 5.57 mm Hg], P Conclusions During biportal endoscopy, we suggest maintaining water pressure between 4.41 cm H2O (2.41 mm Hg) and 31.00 cm H2O (22.83 mm Hg). Compared to physical characteristics, placement of the cannula and appropriate cannula length are important factors that affect water dynamics.

Background: Post-laminectomy syndrome is a common cause of dissatisfaction after endoscopic interlaminar approach. Our aim was to evaluate the efficacy and safety of our two newly designed instruments for laminotomy, a dural protector attached to the scope and a knot pusher for water-tight suturing of the incidental dural tears. Material and Methods: This was a multicenter evaluation. Efficacy was quantified as the pre-to-postoperative improvement in pain (visual analog scale), disability (Oswestry Disability Index), patient satisfaction (modified MacNab score), and length of hospital stay. Safety was quantified by the incidence and location of dural tears, rate of revision, and radiological outcomes. Outcomes were evaluated between the control (before instrument development) and experimental (after instrument development) groups. Results: There was a significant improvement in leg pain in the experimental group (p = 0.03), with greater patient satisfaction in the control group (p < 0.01). There was no incidence of dural tears in the area of the traversing and exiting nerve roots in the experimental group. Water-tightness of sutures was confirmed radiologically. Conclusion: The novel dural protector and the knot pusher for water-tight sutures improved the efficacy and safety of decompression and discectomy; however, a prolonged operative time was a drawback.

PURPOSE: To compare the radiological and clinical outcomes using simple medial meniscus posterior horn (MMPH) root repair using an all-inside meniscal repair device combined with high tibial osteotomy (HTO) and HTO alone. METHODS: Between November 2013 and December 2016, patients treated for MMPH root tear along with HTO were enrolled. Based on the tear gap, the participants were divided into repairable ( 2 mm) categories. The participants in each group were divided into those amenable to simple MMPH root repair using an all-inside meniscal repair device and those that required no procedure for meniscus. Radiological parameters including mechanical femorotibial alignment (MA), posterior tibial slope (PTS) and medial joint-space width (JSW) were evaluated preoperatively and postoperatively at 2 years. For clinical evaluation, the WOMAC score was determined at the 2-year visit postoperatively. RESULTS: A total of 81 knees including 48 repairable (group R) and 33 unrepairable (group I) knees were enrolled. A total of 43 knees underwent simple MMPH root repair using an all-inside meniscal repair device (subgroup r), whereas the other 38 knees did not (subgroup n). The MA, PTS, and their postoperative changes as well as the WOMAC scores showed no differences. However, the JSW in group Rr increased from 3.1 to 3.6 mm, but decreased from 3.7 to 3.4 in group Rn, which was a statistically significant difference. CONCLUSION: Simple MMPH root repair using an all-inside meniscal repair device combined with HTO was more effective for the maintenance of JSW compared with HTO without a meniscal procedure in patients with repairable MMPH root tear and varus alignment. However, other options are needed for unrepairable MMPH root tear.

Arthroscopic partial resection is indicated for patients who have symptomatic discoid meniscus with overall satisfactory clinical outcomes. Reports regarding regeneration of discoid meniscus after arthroscopic surgery are limited. There are only two reports for children in the literature. To the authors’ knowledge, the present study is the first report in the literature to report regeneration of discoid lateral meniscus after arthroscopic partial meniscectomy in an adult patient. The diagnosis was confirmed by both magnetic resonance imaging and arthroscopy. Surgeons should be aware that regeneration of discoid meniscus can occur in adult as well as pediatric patients. Level of evidence V.

The purpose of this study was to assess post-operative patient subjective satisfaction and to analyze associated peri-operative factors following biplanar medial open wedge high tibial osteotomy (OWHTO). The study cohort consisted of 88 patients with a minimum of two years of follow-up. Patient satisfaction was evaluated with a questionnaire that assessed (1) overall satisfaction, (2) pain relief, (3) daily living functions, and (4) cosmesis. Patients were categorized into two groups (satisfied or unsatisfied) based on overall satisfaction questionnaire. Pre- and post-operative objective clinical statuses were assessed with a knee scoring system based on the American Knee Society (AKS), the Western Ontario McMaster University Osteoarthritis Index (WOMAC), and range of motion. Of the 88 patients, 85.2% were graded as satisfied according to the overall satisfaction estimation. The percentage of patients satisfied with pain relief, daily living functions, and cosmesis were 85.2%, 86.4%, and 86.4%, respectively. Multivariable logistic regression analysis demonstrated that pre-operative Hip-Knee-Ankle angle (HKAA) (odds ratio (OR) = 1.812), post-operative AKS knee score (OR = 1.156), and post-operative HKAA (OR = 0.717) were significantly associated with overall satisfaction. Pre-operative HKAA (OR = 1.436), post-operative WOMAC activity score (OR = 0.865), and post-operative HKAA (OR = 0.505) were significant predictors for satisfaction with pain reduction, daily living functions, and cosmesis, respectively. Biplanar medial OWHTO is an effective treatment for osteoarthritis with varus deformity in terms of subjective satisfactory outcome. Several factors, including pre- and post-operative HKAA, post-operative AKS and WOMAC score, were significant predictors for subjective satisfaction. Level of evidence: Level III

Introduction Chronic neck pain in office workers is a prevalent occupational disorder. Recently, smartphone applications (apps) have increased rapidly, and provide the benefits in terms of accessibility to health information. The objective of this study was to examine the effectiveness of an app-based exercise in office workers on pain intensity, functional disability, exercise adherence, muscle strength, quality of life and fear-avoidance. Methods 20 office workers participated in the study excluding one drop-out. The app-based exercise group (n = 11) conducted neck exercise through the mobile app in the workplace environment for at least 10–15 min/day, 2 days/week for 8 weeks while the control group (n = 9) received a brochure showing how to correct their posture themselves during the same period. Evaluations using the following were performed at baseline and after 8 weeks: the Visual Analog Scale (VAS), for pain intensity; Neck Disability Index (NDI), for functional disability; level of exercise adherence; maximal voluntary flexion/extension strength (MVFS/MVES); 36-Item Short-Form Healthy Survey (SF-36), for quality of life; and Fear-Avoidance Belief Questionnaire (FABQ). Results Within the app-based exercise group, the VAS (P = 0.003) and NDI (P = 0.005) improved significantly after the app-based neck exercise. MVES (P = 0.013), physical component summary (P = 0.02) of the SF-36, and the work-related subscale (P = 0.011) in the FABQ improved significantly. The level of exercise adherence was high. In VAS and NDI, there were statistically significant differences in the amounts of improvement between the groups. Conclusion An app-based neck exercise positively effects pain intensity, functional disability and partially improves muscle strength, SF-36 score, and FABQ score.

Background: Tunnel widening (TW) after anterior cruciate ligament (ACL) reconstruction can be a serious complication, and there is controversy over how to prevent it. This study aimed to suggest surgical approaches to prevent TW using an allo-Achilles tendon graft, and then to evaluate TW after these surgical tips were applied. Materials and Methods: Sixty two patients underwent ACL reconstruction with an allo-Achilles tendon graft. Four surgical approaches were used: Making a tibial tunnel by bone impaction, intraarticular reamer application, bone portion application for the femoral tunnel, and an additional bone plug application for the tibial tunnel. After more than 1-year, followup radiographs including anteroposterior and lateral views were taken in 29 patients encompassing thirty knees. The diameter of the tunnels at postoperation day 1 (POD1) and at followup was measured and compared. Results: In 18 knees (60%), there were no visible femoral tunnel margins on the radiographs at POD1 or followup. In the other 12 cases, which had visible femoral tunnel margins on followup radiographs, the mean femoral tunnel diameter was 8.6 mm. In the tibial tunnel, the mean diameters did not increase on all three levels (proximal, middle, and distal), and there was no statistically significant difference between the diameters at POD1 and followup. Conclusion: The suggested tips for surgery involving an allo-Achilles tendon graft can effectively prevent TW after ACL reconstruction according to this case series. These surgical tips can prevent TW.

To explore the feasibility of a newly developed smartphone-based exercise program with an embedded self-classification algorithm for office workers with neck pain, by examining its effect on the pain intensity, functional disability, quality of life, fear avoidance, and cervical range of motion (ROM).Single-group, repeated-measures design.The laboratory and participants' home and work environments.Offices workers with neck pain (N=23; mean age ± SD, 28.13±2.97y; 13 men).Participants were classified as having 1 of 4 types of neck pain through a self-classification algorithm implemented as a smartphone application, and conducted corresponding exercise programs for 10 to 12min/d, 3d/wk, for 8 weeks.The visual analog scale (VAS), Neck Disability Index (NDI), Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), Fear-Avoidance Beliefs Questionnaire (FABQ), and cervical ROM were measured at baseline and postintervention.The VAS (P.001) and NDI score (P.001) indicated significant improvements in pain intensity and functional disability. Quality of life showed significant improvements in the physical functioning (P=.007), bodily pain (P=.018), general health (P=.022), vitality (P=.046), and physical component scores (P=.002) of the SF-36. The FABQ, cervical ROM, and mental component score of the SF-36 showed no significant improvements.The smartphone-based exercise program with an embedded self-classification algorithm improves the pain intensity and perceived physical health of office workers with neck pain, although not enough to affect their mental and emotional states.

Several surgical techniques have been suggested to anatomically reconstruct the posterolateral corner of the knee joint. However, most of them are open techniques that require dissection of the skin and soft tissues without utilizing the advantages of arthroscopic-assisted techniques. Therefore, this study aimed to describe a novel arthroscopic technique that anatomically reconstructs the posterolateral corner of the knee joint. This novel arthroscopic technique can properly identify important landmarks for reconstruction and anatomically reconstruct the three key components (lateral collateral ligament, popliteus tendon, and popliteofibular ligament) of the posterolateral corner of the knee joint.

Extensive bone bleeding and an uncomfortable hematoma can develop due to the opening gap and space during a medial open high tibial osteotomy (HTO). Tranexamic acid (TXA) has been used in various orthopaedic surgeries to reduce bleeding and wound complications. However, no study has investigated the effect of TXA during HTO. Therefore, the purpose of this study is to evaluate the efficacy of TXA in reducing postoperative blood loss in patients undergoing HTO. The hypothesis is that topical TXA administration will reduce postoperative bleeding in patients undergoing medial opening HTO. Topical TXA (2 g in 20 mL saline) was administered at the osteotomy site in patients (n = 15) who underwent medial open HTO from November 2015 to March 2016. Patients (n = 15) who underwent medial open wedge HTO by the same surgeon from October 2014 to October 2015 were enrolled as a control group for comparison. Drainage volumes on postoperative days (PODs) 1, 2, and 3 as well as hemoglobin (Hb) level on PODs 1, 6, and 13 were measured and compared. Mean total postoperative drainage volume was 246 mL in the TXA group and 377 mL in the control group. Mean drainage volume on POD 1 was 138 mL in the TXA group and 277 mL in the control group (p 0.05). An extensive hematoma requiring additional surgery developed in one case in the control group. No wound complications were detected in the TXA group. Topical TXA was effective for reducing postoperative bleeding after medial open HTO. The level of evidence of the study is Level 3.

BACKGROUND Mixed use of T1- or T2-weighted magnetic resonance imaging (MRI) in histographic analysis has impeded cross-reference of studies on fatty degeneration of muscles in patients with back pain. OBJECTIVE The current study aimed to establish the measurement reliability of histographic analysis for normal and painful paraspinal muscles between T1- and T2-weighted MRI. METHODS T1- and T2-weighted MRI at the L4-5 level were performed in 31 patients with unilateral back pain. Two raters conducted the histographic analysis on 2 separate occasions. Multifidus, erector spinae, and psoas major muscles were assessed on both normal and painful sides. RESULTS Intra- and interrater reliability of the parameters were generally excellent for both T1- (intrarater: 0.83 ± 0.13 and interrater: 0.93 ± 0.08) and T2-weighted images (intrarater: 0.93 ± 0.12 and interrater: 0.92 ± 0.12). Histogram width was fair to good for both kinds of image. Intraclass correlation coefficients were similar between painful and normal sides. CONCLUSIONS The evidence that most histographic analysis parameters had excellent reliability for both T1- and T2-weighted images allows for cross-reference of the results between the two kinds of image. Moreover, the results of this study support the availability of histographic analysis for assessment of fatty degeneration in patients with back pain.

This mediolateral excursion of the bearing during knee motion is supposed to be caused by external rotation of the tibia during knee extension. However, to our knowledge, there is no published clinical evidence supporting these hypotheses. The current study aimed to evaluate the mediolateral excursion of the bearing during flexion-extension motion of the knee after medial unicompartmental knee arthroplasty (UKA). In 52 knees, varus/valgus (F-VarVal) or rotational position (F-Rot) of the femoral component and relative location of the bearing were measured with the standing anteroposterior and modified axial view, respectively. We adopted the modified axial radiographs that are simple to assess the bearing position in the flexed knee. The modified axial view showed excellent inter- and intraobserver agreements. F-Rot in the modified axial view and CT showed a high agreement in terms of validity (r = 0.98; p

Medial opening wedge high tibial osteotomy (HTO) has become increasingly popular as an alternative to lateral closing wedge osteotomy for the treatment of medial compartment knee osteoarthritis with varus deformity. The present systematic review was conducted to provide an objective analysis of total knee arthroplasty (TKA) outcomes following previous knee osteotomy (medial opening wedge vs. lateral closing wedge). A literature search of online databases (MEDLINE, EMBASE, Cochrane Library database) was made, in addition to manual search of major orthopaedic journals. The methodological quality of each of the studies was assessed on the Newcastle–Ottawa Scale and Effective Practice and Organization of Care. A total of ten studies were included in the review. There were eight studies with Level IV and two studies with Level III evidence. Eight studies reported clinical and radiologic scores. Comparative studies between TKA following medial opening and lateral closing wedge HTO did not demonstrate statistically significant clinical and radiologic differences. The revision rates were similar. However, more technical issues during TKA surgery after lateral closing wedge HTO were mentioned than the medial open wedge group. The quadriceps snip, tibial tubercle osteotomy, and lateral soft tissue release were more frequently needed in the lateral closing wedge HTO group. In addition, because of loss of proximal tibia bone geometry in the lateral closing wedge HTO group, concerns such as tibia stem impingement in the lateral tibial cortex was noted. The present systematic review suggests that TKA after medial opening and lateral closing wedge HTO showed similar performance. Clinical and radiologic outcome including revision rates did not statistically differ from included studies. However, there are more surgical technical concerns in TKA conversion from lateral closing wedge HTO than from the medial opening wedge HTO group. IV.