TNF-α Suppresses Apelin Receptor Expression in Mouse Quadriceps Femoris-Derived Cells.

Expression of the apelin receptor, APJ, in skeletal muscle (SM) is known to decrease with age, but the underlying mechanism remains unclear. Increased tumor necrosis factor (TNF)-α levels are observed in SM with age and are associated with muscle atrophy. To investigate the possible interconnection between TNF-α elevation and APJ reduction with aging, we investigated the effect of TNF-α on APJ expression in cells derived from the quadriceps femoris of C57BL/6J mice. Expression of Tnfa and Apj in the quadriceps femoris was compared between 4- (young) and 24-month-old (old) C57BL/6J mice (n = 10 each) using qPCR. Additionally, APJ-positive cells and TNF-α protein were analyzed by flow cytometry and Western blotting, respectively. Further, quadricep-derived cells were exposed to 0 (control) or 25 ng/mL TNF-α, and the effect on Apj expression was examined by qRT-PCR. Apj expression and the ratio of APJ-positive cells among quadricep cells were significantly lower in old compared to young mice. In contrast, levels of Tnfa mRNA and TNF-α protein were significantly elevated in old compared to young mice. Exposing young and old derived quadricep cells to TNF-α for 8 and 24 h caused Apj levels to significantly decrease. TNF-α suppresses APJ expression in muscle cells in vitro. The increase in TNF-α observed in SM with age may induce a decrease in APJ expression.

Increased nerve growth factor expression in the synovial tissues of patients with rotator cuff tears.

BACKGROUND: Rotator cuff tears (RCTs) are often associated with severe shoulder pain. Non-steroidal anti-inflammatory drugs, not recommended for long-term use, do not effectively manage RCT-induced pain, resulting in reduced quality of life. To improve management, a better understanding of the fundamental properties of RCT pain is needed. Here, we aimed to compare the expression levels of nerve growth factor (NGF) and cyclooxygenase-2 (COX-2) mRNA in the synovial tissues of patients with RCT-induced pain and patients with non-painful recurrent shoulder dislocation (RSD). METHODS: The study included 32 patients with RCT who underwent arthroscopic rotator cuff repair and 28 patients with non-painful RSD who underwent arthroscopic Bankart repair. Synovial tissue samples were harvested from subacromial bursa and rotator interval of RCT patients and from the rotator interval of RSD patients. Samples were analyzed quantitatively expression levels for NGF and COX2 mRNA and NGF protein. RESULTS: NGF mRNA and protein levels were significantly higher in the rotator interval of RCT patients than in the rotator interval of RSD patients (p = 0.0017, p = 0.012, respectively), while COX2 mRNA levels did not differ significantly between the two patient groups. In RCT patients, COX2 mRNA was more highly expressed in the rotator interval than in the subacromial bursa (p = 0.038), whereas the mRNA and protein levels of NGF did not differ between the two tissues. The expression of NGF mRNA in the synovium of the rotator interval was significantly correlated with the numeric rating scale of pain (ρ = 0.38, p = 0.004). CONCLUSION: NGF mRNA and protein levels were elevated in patients with painful RCT compared with those in patients with non-painful RSD, whereas COX-2 levels were comparable in the two patient groups. These findings provide insights into novel potential strategies for clinical management of RCT.

Biomechanical evaluation of internal fixation for the treatment of comminuted subtrochanteric femur fractures.

BACKGROUND: Several biomechanical studies on subtrochanteric femur fractures have reported that use of an intramedullary nail is superior to extramedullary implant. However, the optimal choice of intramedullary nail for the treatment of comminuted subtrochanteric femur fracture remains unclear. Here, we evaluated the biomechanical properties of comminuted subtrochanteric femur fracture treated with four different internal fixations. METHODS: A comminuted subtrochanteric femur fracture model was created with a 2-cm gap below the lessor trochanter in 20 synthetic femurs. The fractures were fixed with one of four implants - Antegrade Femoral Nail (AFN), Trochanteric Fixation Nail Advanced with a femoral neck blade (TFNA blade), TFNA with a femoral neck screw (TFNA screw), and the reversed distal femoral locking compression plate (DF-LCP) - all manufactured by DePuy Synthes. Axial compression tests and torsion tests were performed and the stiffness of each implant was compared. RESULTS: For compression, the TFNA blade, TFNA screw, and AFN provided significantly higher stiffness than DF-LCP (p < 0.001, p < 0.001, p = 0.001, respectively), and the TFNA blade provided significantly higher stiffness than AFN (p = 0.049). For torsion, there were no significant differences among the groups in internal rotation, while the TFNA screw had significantly lower torsional stiffness than the AFN, TFNA blade and DF-LCP in external rotation (p = 0.036, p = 0.034, p = 0.037, respectively). CONCLUSIONS: These findings could help to provide biomechanical evidence regarding choice of implant for the treatment of comminuted subtrochanteric femur fracture. The TFNA blade may be more suitable for the treatment of comminuted subtrochanteric femur fracture.

Expression and regulation of macrophage-inducible C-type lectin in human synovial macrophages.

Recent evidence suggests that synovial macrophage activation may be involved in cartilage destruction and pain in osteoarthritis (OA). The macrophage-inducible C-type lectin (Mincle) Clec4e is expressed in macrophages and is regulated in inflammatory conditions. Given that the regulation of Mincle in synovial macrophages has not been elucidated, we investigated the expression and regulation of Mincle in human synovial tissue (ST) harvested from patients with radiographic knee OA during total knee arthroplasty. Immunohistochemical and flow cytometric analyses were used to identify cells with Mincle expression in resected tissues. CD14-positive (CD14+; macrophage-rich cell fraction) and CD14-negative (CD14-; fibroblast-rich cell fraction) cells were extracted from the ST and used to assess MINCLE mRNA expression levels. To determine the role of tumor necrosis factor alpha (TNF-α) in the regulation of MINCLE expression, TNF-α was used to stimulate cultured CD14+ cells. Immunohistochemical staining revealed Mincle-positive cells in the synovial lining layer. Flow cytometric analysis showed that CD45+CD14+ cells were Mincle positive while CD45-/CD14- cells were Mincle negative. MINCLE expression was significantly higher in CD14+ cells than in CD14- cells. Stimulation of cultured CD14+ macrophages with TNF-α significantly increased MINCLE mRNA expression, while stimulation with TNF-α neutralizing antibody significantly decreased expression. That Mincle expression was observed in synovial macrophages and its expression was induced by TNF-α suggests that Mincle might have a key role in synovial inflammation in the osteoarthritic synovium.

Elevated leptin levels induce inflammation through IL-6 in skeletal muscle of aged female rats.

BACKGROUND: Chronic inflammation with aging contributes to sarcopenia. Previous studies have suggested that the accumulation of adipose tissue in skeletal muscle, referred to as intermuscular adipose tissue (IMAT), increases with age and is associated with inflammation. However, the mechanism governing ectopic inflammation in skeletal muscle due to aging is not fully understood. Leptin, an adipocytokine derived from adipose tissue, is an important mediator of inflammatory processes. We examined changes in leptin levels with age and whether leptin contributes to ectopic inflammation. METHODS: To evaluate ectopic inflammation in skeletal muscle, we measured alterations to the expression of inflammatory cytokine genes (Il1b, Il6, and Tnfa) and muscle break down-related gene (MuRF1 and Atrogin1) in the quadricep muscles of young (10 weeks) and aged (48 weeks) female rats using quantitative reverse-transcription polymerase chain reaction (Q-RT-PCR). Histological examination was performed to identify the extent of IMAT. Leptin mRNA and leptin protein expression were examined using Q-RT-PCR and enzyme-linked immunosorbent assay, respectively. The effect of leptin on the mRNA expression of Il1b, Il6, and Tnfa in quadricep muscle-derived cells was also examined by stimulating the cells with 0 (control), 1, or 10 µg/mL rat recombinant leptin using Q-RT-PCR. RESULTS: Aged rats had significantly higher Il6, MuRF1, and Atrogin1 but not Il1b and Tnfa, expression and greater levels of IMAT in their quadricep muscles than young rats. Aged rats also had significantly higher leptin expression and leptin protein concentration in their quadricep muscles than young rats. The addition of exogenous leptin to quadricep muscle-derived cells significantly increased the gene expression of Il1b and Il6 but not Tnfa. CONCLUSIONS: Our results suggest that elevated leptin levels due to aging cause ectopic inflammation through IL-6 in the skeletal muscle of aged rats.

Comparison of glenohumeral joint rotation between asymptomatic subjects and patients with subacromial impingement syndrome using cine-magnetic resonance imaging: a cross-sectional study.

BACKGROUND: The purpose of this study to compare glenohumeral joint motion during active shoulder axial rotation between subacromial impingement syndrome (SIS) shoulders and asymptomatic shoulders using cine-magnetic resonance imaging (cine-MRI). Measurement of glenohumeral joint motion via manual intervention does not assess the usual glenohumeral joint motion, and the glenoid surface cannot be confirmed manually. However, cine-MRI can produce clear images of glenohumeral joint rotation. Therefore, we sought to measure the active ROM of the glenohumeral rotation using cine-MRI. METHODS: Seventy-three shoulders in 42 asymptomatic volunteers and 110 SIS shoulders in 103 consecutive patients were included in this study. We evaluated 36 matched pairs (72 shoulders in total) adjusting for baseline characteristics with propensity score matching method. The patients underwent cine-MRI during axial rotation of the adducted arm. During imaging, participants rotated their shoulder from the maximum internal rotation to the maximum external rotation over the first 10 s and then back to the maximum internal rotation over the subsequent 10 s. We assessed internal/external rotation, and compared the asymptomatic and SIS shoulders in this regard. Evaluation of rotation angles was performed on a series of axial images through the humeral head center. RESULTS: The mean internal rotation angles of the asymptomatic and patient groups were 55° ± 10° and 41° ± 23°, respectively, (P = .002; 95% Confidence Interval [CI], 51-58 vs 33-49); the mean external rotation angles were 47° ± 15° and 21° ± 25°, respectively, (P < .001; CI, 42-52 vs 13-29). CONCLUSIONS: Compared to asymptomatic shoulders, SIS shoulders showed significantly restricted glenohumeral rotation as determined by cine-MRI. Our results suggested that the significant limitation of active glenohumeral rotation might be associated with rotator cuff dysfunction.

Comparison of Subacromial Bursitis on the Shoulder of the Same Individual After Superior Capsule Reconstruction Using Allograft and Rotator Cuff Tear: A Case Report.

This paper reports a pathological comparison between the synovium of the shoulder with rotator cuff tears (RCTs) with or without an allograft in the same patient and assesses allograft remodeling after superior capsular reconstruction (SCR). A 49-year-old man underwent SCR with a fascia lata allograft for irreparable RCTs. Two years postoperatively, the patient underwent arthroscopic rotator cuff repair for left RCTs and arthroscopic debridement to alleviate right shoulder pain. Additionally, revascularization was confirmed in the allograft of the fascia lata. In conclusion, allografts are considered highly safe and expected to be engrafted after SCR.

Kinematic analysis of damaged capsulolabral structure in patients with anterior shoulder instability using cine-magnetic resonance imaging.

Background: We assessed damaged anterior capsulolabral motion during axial shoulder rotation in patients with anterior shoulder instability. Methods: Twenty-nine shoulders of 28 patients with anterior shoulder instability who underwent cine-magnetic resonance imaging during axial rotation of the adducted arm were included. The motion was captured after an intra-articular injection of saline solution (10-20 mL). During imaging, the shoulder was rotated passively from maximum internal rotation to maximum external rotation in the first 10 s and then back to maximum internal rotation in the subsequent 10 s. We assessed the rotational angles of the damaged labrum during compressing and pulling the humeral head against the glenoid. Evaluation of the rotational angles was performed on a series of axial images through the humeral head center. Results: The mean angles that damaged labrum compressed and pulled off against the glenoid were 12.0 ± 19.1° and 2.8 ± 21.2°, respectively. Additionally, seven of the 29 shoulders showed that the damaged labrum compressed on the glenoid rim before the rotational angle exceeded 0° during external rotation. In 13 shoulders, the damaged labrum could remain repositioned on the glenoid rim over the neutral position during internal rotation. In two shoulders, the damaged labrum was not compressed against the glenoid at the maximum external rotation. The injected saline moved from the posterior to the anterior side of the glenohumeral joint during internal rotation in each shoulder. Conclusion: The damaged labrum could be positioned on the glenoid when the arm was in a traditional internal immobilization.

In situ-formed hyaluronan gel/BMP-2/hydroxyapatite composite promotes bone union in refractory fracture model mice.

BACKGROUND: A combination of synthetic porous materials and BMP-2 has been used to promote fracture healing. For bone healing to be successful, it is important to use growth factor delivery systems that enable continuous release of BMP-2 at the fracture site. We previously reported that in situ-formed gels (IFGs) consisting of hyaluronan (HyA)-tyramine (TA), horseradish peroxidase and hydrogen peroxide enhance the bone formation ability of hydroxyapatite (Hap)/BMP-2 composites in a posterior lumbar fusion model. OBJECTIVE: We examined the effectiveness of IFGs-HyA/Hap/BMP-2 composites for facilitating osteogenesis in refractory fracture model mice. METHODS: After establishing the refractory fracture model, animals were either treated at the site of fracture with Hap harboring BMP-2 (Hap/BMP-2) or IFGs-HyA with Hap harboring BMP-2 (IFGs-HyA/Hap/BMP-2) (n = 10 each). Animals that underwent the fracture surgery but did not receive any treatment were considered the control group (n = 10). We determined the extent of bone formation at the fracture site according to findings on micro-computed tomography and histological studies four weeks following treatment. RESULTS: Animals treated with IFGs-HyA/Hap/BMP-2 demonstrated significantly greater bone volume, bone mineral content and bone union than those treated with vehicle or IFG-HyA/Hap alone. CONCLUSIONS: IFGs-HyA/Hap/BMP-2 could be an effective treatment option for refractory fractures.

In Vivo Kinematic Analysis of the Axial Shoulder Rotation in the Standing and Supine Positions Using 3D/2D Registration and Electromyography.

Background There has been no report comparing shoulder kinematics and muscle activities during axial shoulder rotation in different positions. The purpose of this study was to investigate differences in shoulder kinematics and muscle activities during axial shoulder rotation in healthy subjects between standing and supine positions using three-dimensional/two-dimensional (3D/2D) registration techniques and electromyography (EMG). Methods Eleven healthy males agreed to participate in this study. We recorded the fluoroscopy time during active shoulder axial rotation with a 90° elbow flexion in both standing and supine positions, simultaneously recording surface EMG of the infraspinatus, anterior deltoid, posterior deltoid, and biceps brachii. Three-dimensional bone models were created from CT images, and shoulder kinematics were analyzed using 3D/2D registration techniques. Muscle activities were evaluated as a ratio of mean electromyographic values to 5-sec maximum voluntary isometric contractions.  Results Scapular kinematics during axial shoulder rotation in the supine position showed similar patterns with those in the standing position. The scapula was more posteriorly tilted and more downwardly rotated in the supine posture than in standing (P < 0.001 for both). Acromiohumeral distance (AHD) in the supine posture was significantly larger than in standing. Muscle activities showed no significant differences between postures except for biceps (P < 0.001). Discussion Shoulder kinematics and muscle activities during axial rotation were similar in pattern between standing and supine postures, but there were shifts in scapular pose and AHD. The findings of this study suggest that posture may be an important consideration for the prescription of optimal shoulder therapy following surgery or for the treatment of shoulder disorders.

Evaluation of flexor digitorum superficialis function in adolescent baseball players.

Hypothesis and/or Background: Increased flexor digitorum superficialis (FDS) tendon activity can be a therapeutic target for elbow disorders in adolescent baseball players. The proportion of adolescent baseball players who can use FDS independently is unknown, and which finger is most often used remains unclear. This study investigated whether adolescent baseball players intentionally used FDS on each finger. Methods: Adolescent baseball players were recruited and assessed for FDS function for each finger using the standard technique. Results: Sixty-nine participants (mean age: 10.4 years) were recruited. Participants numbered 33, 56, 59, and 25 on the throwing side and those numbered 28, 46, 54, and 33 on the nonthrowing side could independently flex the proximal interphalangeal joint while holding their palms in the index, middle, ring, and small fingers, respectively. When assessing both throwing and nonthrowing participants, a significant number of participants could independently flex the proximal interphalangeals of the ring and middle fingers but had difficulty with the index and small fingers (P < .001). No significant difference was noted between the throwing and nonthrowing participants in any finger (P > .05). Discussion and/or Conclusion: One study reported that participating baseball players with elbow pain have more medial elbow joint space than those without pain symptoms. In another study on finger movements during pitching motion, the force of the thumb, index, middle, and ring fingers was greatest immediately before maximum external rotation. According to both reports, FDS function, especially in the index finger, can be a therapeutic target for medial-sided elbow injuries in adolescent baseball players.

Elevation of MMP1 and ADAMTS5 mRNA expression in glenohumeral synovia of patients with hypercholesterolemia.

BACKGROUND: Epidemiological studies have reported a positive association between hypercholesterolemia and shoulder disease. Previous studies have focused on the effect of hypercholesterolemia on tendinopathy. Moreover, hypercholesterolemia has also been linked to joint pathology in the knee and hand. However, the effect of hyperlipidemia on glenohumeral joint remain unclear. A hypercholesterolemic condition has been reported to alter levels of A Disintegrin and Metalloprotease with Thrombospondin Motifs (ADAMTSs) and matrix metalloproteases (MMPs) in synovium of the knee joint. Here, we evaluated the mRNA expression of ADAMTSs and MMPs in the glenohumeral synovium of patients with and without hypercholesterolemia. METHODS: Study participants were 73 patients who underwent arthroscopic rotator cuff repair for degenerative rotator cuff tears. They were divided into two groups according to total cholesterol (TC) and triglyceride levels. Synovial membrane samples were harvested at the rotator interval during surgery, and mRNA expression levels of the aggrecanases ADAM-TS4 and ADAM-TS5 and MMPs (MMP-1, 3, 9, and 13) were analyzed quantitatively. RESULTS: ADAM-TS5 and MMP1 mRNA levels were significantly higher in the high TC group than in the low TC group (P = 0.023 and P = 0.025, respectively). In contrast, no significant differences were observed in ADAMTS4 or MMPs 3, 9, and 13 (ADAMTS4, P = 0.547; MMP3, P = 0.55; MMP9, P = 0.521; and MMP13, P = 0.785). CONCLUSION: Hypercholesterolemia may alter MMP1 and ADAMTS5 expression in the synovium of the glenohumeral joint.

Expression of nerve growth factor in the callus during fracture healing in a fracture model in aged mice.

BACKGROUND: Impaired fracture healing results in extensive and prolonged disability and long-term pain. Previous studies reported that nerve growth factor (NGF) was expressed during fracture healing and that anti-NGF antibody improves physical activity associate with facture pain. However, NGF expression levels in delayed or non-union are not fully understood. OBJECTIVE: We compared chronological changes in NGF in the callus of young mice after femur fracture with those in aged mice after femur fracture as a model of bone fracture in the elderly. METHODS: We used young (age 8 weeks) and aged (age 10 months) male C57BL/6J mice. A fracture was generated in the femur. At 5, 7, 10, 14, 17, and 21 days after creation of a fracture, mRNA expression levels of Col2a1, Col10a1, NGF were evaluated using quantitative PCR. We examined NGF protein expression levels and localization in the callus at day 14 using ELISA and immunohistochemistry, respectively. RESULTS: Expression of NGF in the callus after femur fracture in aged mice was significantly greater than that in young mice at days 5, 7, 10, 17, and 21 days. NGF protein levels in the callus of aged mice were also significantly higher than that in young mice. Immunohistochemical staining showed that NGF was heavily expressed in hypertrophic chondrocytes in the callus in aged mice. CONCLUSIONS: It is suggested that delayed Col2a1 and Col10a1 expression reflects delayed chondrocyte formation and delayed chondrocyte maturation in aged mice and that higher NGF expression in aged mice at day 14 may be associated with the presence of remaining hypertrophic chondrocytes in callus with delaying endochondral ossification.

Tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis: results of 2 years of follow-up.

Hypothesis: We hypothesized that the treatment of recalcitrant lateral epicondylitis requires accurate identification of the painful area to promote remodeling of the degenerated extensor insertion and to stabilize the tendon origin during tendon healing. Thus, we performed tenodesis with bone marrow venting under local anesthesia for recalcitrant lateral epicondylitis. Methods: Twenty patients (21 elbows) were treated with bone marrow venting at the painful area of the lateral epicondyle of the elbow and tenodesis using 2 soft anchors lateral to the capitellum (immediately distal to the painful area) and were followed up for ≥2 years. Patients were assessed using the numerical rating scale for pain and the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire, and objective evaluation included active range of motion. Results: The mean preoperative and postoperative pain scores were 7.5 and 0.5, respectively, indicating significant pain relief (P < .001). The mean preoperative and postoperative Quick Disabilities of the Arm, Shoulder, and Hand questionnaire scores were 44.2 and 1.0, respectively (P < .001). Two elbows had a slightly positive Thomsen test at the final visit. No recurrence of intra-articular symptoms induced by synovial fringe impingement was observed. Patients experienced more pain at the bone-tendon junction of extensors than at the tendon parenchyma. Conclusion: Tenodesis with bone marrow venting under local anesthesia was effective for subjective patient satisfaction and positive clinical outcomes at ≥2 years of follow-up in patients with recalcitrant lateral epicondylitis. Intra-articular symptoms can be improved by stabilization of the lateral soft tissue without treatment for intra-articular lesions.

Mild inflammation persists in the glenohumeral joint of patients with shoulder instability: Cross-sectional study.

Objective: Approximately two-thirds of patients with history of shoulder dislocation may develop osteoarthritis (OA) of the glenohumeral joint. However, the biochemical mechanisms underlying the association between dislocation and OA are largely unknown. This study aimed to investigate macrophage markers and inflammatory cytokine expression associated with shoulder instability (SI) in comparison to rotator cuff tears (RCTs). Design: This study included 30 patients with SI and 30 patients with RCTs. Synovial membrane samples were harvested from the rotator interval during the arthroscopic anatomical repair for both groups. The localization of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and cluster of differentiation (CD) 68 in synovial membranes was determined by immunohistochemistry. Transcript-level expressions of the inflammatory cytokines (TNFA and IL1B) and macrophage markers pan-CD68 and -M1 (CD80 and CD86) were quantified. CD80 and CD86 expression in macrophages from the SI group was confirmed using flow cytometry. Results: TNF-α, IL-1ß, and CD68 were expressed in the synovial lining layer of the synovial tissue in both groups. In addition, the mRNA expressions of TNFA, IL1B, CD68, and CD80 were significantly higher in the SI group compared to the RCT group (P â€‹= â€‹0.012, 0.014, 0.022, 0.003, respectively). In samples from the SI group, 96.3% of CD68+/CD14+ macrophages were CD86-positive, whereas 2.5% of CD68+/CD14+/CD86+ cells were CD80-positive. Conclusions: Patients with SI had higher mRNA levels of TNFA, IL1B, CD68, and CD80 than those with RCTs. These findings may partially explain the biochemical mechanism underlying the frequent development and progression of osteoarthritis in patients with SI.

Biomechanical Evaluation of Extramedullary Versus Intramedullary Reduction in Unstable Femoral Trochanteric Fractures.

INTRODUCTION: The failure rate of operations involving the cephalomedullary nail technique for unstable femoral trochanteric fractures is 3-12%. Changing the reduction strategy may improve the stability. This study aimed to confirm whether reducing the proximal fragment with the medial calcar contact, as opposed to utilizing an intramedullary reduction, would improve the stability of such fractures. MATERIALS AND METHODS: The unstable femoral trochanteric fracture model was created with fixation by cephalomedullary nails in 22 imitation bones. The 2 reduction patterns were as follows: one was with the proximal head-neck fragment external to the distal bone in the frontal plane and anterior in the sagittal plane as "Extramedullary," while the other was the opposite reduction position, that is, bone in the frontal plane and sagittal plane as "Intramedullary." We evaluated the tip-apex distance, compression stiffness, change in femoral neck-shaft angle, amount of blade telescoping, and diameter of the distal screw hole after the compression test. Statistical analysis was conducted using the Mann-Whitney U test. RESULTS: No significant differences were seen in compression stiffness (p = 0.804) and femoral neck-shaft angle change (p = 0.644). Although the "Extramedullary" tip-apex distance was larger than the "Intramedullary" distance (p = 0.001), it indicated clinically acceptable lengths. The amount of blade telescoping and the distal screw hole diameter were significantly larger in "Intramedullary" than in "Extramedullary" (p < 0.001, p = 0.019, respectively). Our results showed that "Intramedullary" had significantly larger blade telescoping and distal screw hole diameters than "Extramedullary," and contrary to our hypothesis, no significant differences were seen in compression stiffness and femoral neck-shaft angle change. CONCLUSIONS: As opposed to the "Intramedullary" reduction pattern, the biomechanical properties of the "Extramedullary" reduction pattern improved stability during testing and decreased sliding.

Limitation of the external glenohumeral joint rotation is associated with subacromial impingement syndrome, especially pain.

BACKGROUND: Subacromial impingement syndrome is a common disorder associated with functional impairment and disability of the shoulder. Internal/external glenohumeral rotation is important for shoulder function. However, because it is difficult to measure the glenohumeral joint rotation angle physically, the relationship between this angle and the clinical symptoms of subacromial impingement syndrome is still largely unknown. Using advanced cine-magnetic resonance imaging techniques, we designed a study to improve our understanding of the nature of this relationship. METHODS: We evaluated 100 shoulders with subacromial impingement syndrome. Patients underwent cine-magnetic resonance imaging during axial rotation with the arm adducted. During imaging, patients rotated their shoulder from maximum internal rotation to maximum external rotation over 10 seconds and then to maximum internal rotation over 10 seconds. The rotation angles were then evaluated using a series of axial images. The Constant-Murley (Constant) and UCLA scores for each patient were determined, and the correlation between the scores and rotational angles was assessed. Patients were divided into 3 groups according to the Constant pain score, and the rotational angles of each group were compared. Rotational angles were also compared between shoulders with and without night pain. RESULTS: The external rotation angle showed a significant but low correlation with the Constant and UCLA scores (ρ = 0.24 and 0.24, respectively), whereas the internal rotation angle did not. In comparing the pain groups of Constant score and UCLA score, the external rotation angle significantly decreased as pain increased (P < .01), demonstrating a negative correlation (ρ = -0.47, -0.41, respectively). Additionally, the shoulders of patients with night pain showed significantly more restriction of external rotation angles than the shoulders of those without night pain (P = .01). CONCLUSIONS: Limitation of the glenohumeral joint's external rotation is correlated with pain, for which we explore possible explanations. The results suggest that night pain can be effectively reduced using therapeutic interventions that target external rotational dysfunction.

Increasing transforming growth factor-beta concentrations with age decrease apelin in the rat rotator cuff.

BACKGROUND: The rotator cuff undergoes natural degeneration with age, leading to age-related rotator cuff tear; however, the precise mechanism remains unclear. Transforming growth factor-beta (TGF-ß) concentrations rise with age and TGF-ß contributes to the pathophysiology of skeletal muscle. TGF-ß has also been shown to suppress expression of the myokine, apelin, in skin fibroblasts. We hypothesized that TGF-ß expression in the rotator cuff changes with age and regulates apelin expression, thereby contributing to rotator cuff degeneration. METHODS: We used quantitative reverse-transcription polymerase chain reaction (Q-RT-PCR) to measure the expression of apelin and tendon-related genes (Tnmd, Col1a1, and Col3a1) in the rotator cuff of young (12 weeks), adult (24 weeks), and old (48 weeks) rats. Using Q-RT-PCR and enzyme-linked immunosorbent assay, we also measured Tgfb mRNA and TGF-ß protein levels, respectively. Furthermore, we used Q-RT-PCR to measure apelin mRNA levels in rotator cuff-derived cells after treatment with 0 (control) and 10 ng/mL recombinant TGF-ß. RESULTS: Apelin mRNA levels were significantly lower in old compared to young and adult rats. Similarly, tendon-related genes, Tnmd, Col1a1, and Col3a1, were significantly lower in adult and old rats than young rats. In contrast, Tgfb mRNA and TGF-ß protein were significantly higher in old compared to young rats. Stimulation with exogenous TGF-ß significantly decreased Apelin mRNA expression compared to control. CONCLUSIONS: TGF-ß regulates apelin expression in the rotator cuff and may play a key role in the degenerative pathology of the rotator cuff with age.

Acceleration of bone formation using in situ-formed hyaluronan-hydrogel containing bone morphogenetic protein-2 in a mouse critical size bone defect model.

BACKGROUND: An enzymatic crosslinking strategy using hydrogen peroxide and horseradish peroxidase is receiving increasing attention for application with in situ-formed hydrogels (IFHGs). IFHGs may also be ideal carrier materials for bone repair, although their ability to carry bone morphogenetic protein-2 (BMP2) has yet to be examined. OBJECTIVE: We examined the effectiveness of an IFHG made of hyaluronan (IFHG-HA) containing BMP2 for promoting bone formation in a mouse critical size bone defect model. METHODS: C57/BL6J mice received a 2-mm femoral critical-sized bone defect before being randomly assigned to one of the following treatment groups (n = 6): control (no treatment), IFHG-HA only, PBS with BMP2, and IFHG-HA with BMP2. X-ray radiographs were utilized to track new bone formation, and micro-computed tomography and histological examination were performed on new bone formed at the bone defect site two weeks after surgery. RESULTS: Mice treated with PBS with BMP2 and IFHG-HA with BMP2 had greater bone volume (BV) and bone mineral content (BMC) than those receiving control, and successfully achieved consolidation. Mice treated with IFHG-HA with BMP2 had significantly higher BV and BMC than those treated with PBS with BMP2. CONCLUSIONS: IFHG-HA may be an effective carrier for BMP2 to enable delivery for bone defect repair.

Arthroscopic Superior Capsule Reconstruction for Cuff Tear Arthropathy (Hamada Grade 5): A Case Report.

CASE: We performed arthroscopic superior capsule reconstruction (ASCR) for cuff tear arthropathy (CTA) with humeral head deformity. A 62-year-old man presented with severely limited shoulder motion and recalcitrant omalgia. He had a history of dental implant removal due to metal allergy, and his Constant score was 21 points. We diagnosed CTA with Hamada classification grade 5 and performed ASCR to avoid allergic reactions. Severe night pain improved within 1 week of ASCR, and his Constant score after 2 years was 74 points. CONCLUSION: ASCR may be an effective alternative treatment for patients with CTA with humeral head deformity.