Evaluation of myostatin as a possible regulator and marker of skeletal muscle-cortical bone interaction in adults.

INTRODUCTION: Bone mass was recently reported to be related to skeletal muscle mass in humans, and a decrease in cortical bone is a risk factor for osteoporosis. Because circulating myostatin is a factor that primarily controls muscle metabolism, this study examined the role of myostatin in bone mass-skeletal muscle mass interactions. METHODS: The subjects were 375 middle-aged community residents with no history of osteoporosis or sarcopenia who participated in a health check-up. Cortical bone thickness and cancellous bone density were measured by ultrasonic bone densitometry in a health check-up survey. The subjects were divided into those with low cortical bone thickness (LCT) or low cancellous bone density (LBD) and those with normal values (NCT/NBD). Bone metabolism markers (TRACP-5b, etc.), skeletal muscle mass, serum myostatin levels, and lifestyle were then compared between the groups. RESULTS: The percentage of diabetic participants, TRACP-5b, and myostatin levels were significantly higher, and the frequency of physical activity, skeletal muscle mass, grip strength, and leg strength were significantly lower in the LCT group than in the NCT group. The odds ratio (OR) of high myostatin levels in the LCT group compared with the NCT group was significant (OR 2.17) even after adjusting for related factors. Between the low cancellous bone density (LBD) and normal cancellous bone density (NBD) groups, significant differences were observed in the same items as between the LCT and NCT groups, but no significant differences were observed in skeletal muscle mass and blood myostatin levels. The myostatin level was significantly negatively correlated with cortical bone thickness and skeletal muscle mass. CONCLUSIONS: A decrease in cortical bone thickness was associated with a decrease in skeletal muscle mass accompanied by an increase in the blood myostatin level. Blood myostatin may regulate the bone-skeletal muscle relationship and serve as a surrogate marker of bone metabolism, potentially linking muscle mass to bone structure.

Therapeutic outcomes of muscular advancement by an arthroscopic-assisted modified Debeyre-Patte procedure for irreparable large and massive rotator cuff tears.

BACKGROUND: In cases of the large or massive rotator cuff tears, retear rates after rotator cuff repairs remain high. We introduced an arthroscopic-assisted modified Debeyre-Patte procedure which enables to decrease the tension of torn rotator cuff by sliding supraspinatus and infraspinatus laterally keeping fascia connection to the rhomboids. PURPOSE: The objective of this study was to examine the clinical outcomes and retear rates after an arthroscopic-assisted modified Debeyre-Patte procedure for irreparable large and massive rotator cuff tears. METHODS: Thirty-three rotator cuff tear patients (34 shoulders) were selected. These patients underwent arthroscopic-assisted modified Debeyre-Patte procedures and were observed postoperatively for at least 24 months. Magnetic resonance imaging (MRI) was used to evaluate the preoperative location of the torn rotator cuff stump and fatty infiltration of the muscles composing the rotator cuff, as well as the repaired rotator cuffs. Shoulder functional evaluations through the use of the Constant and Murley scores and the University of California Los Angeles (UCLA) shoulder score were compared before and after surgery, and the preoperative global fatty degeneration index (GFDI) was compared between retear and healed shoulders. RESULTS: MRI showed that 77% of shoulders were healed and 23% exhibited retear postoperatively. The mean preoperative GFDI was 1.99 among the 26 healed shoulders and 2.54 among the 8 retear shoulders (p < .05). When the Goutallier's classification was grade 3 or lower for all 3 cuff muscles for fatty infiltration, the retear rate was 14.3%. The mean Constant and Murley scores in healed and retear groups respectively improved from 34.7 ± 15.8, 30.0 ± 15.1 points (p = 0.47) preoperatively to 70.8 ± 8.3, 53.9 ± 14.0 points (p < .001), and UCLA scores in healed and retear groups from 13.8 ± 3.9, 12.4 ± 5.0 points (p = 0.46) preoperatively to 32.8 ± 2.7, 28.4 ± 3.6 points (p < .001). CONCLUSION: The clinical outcomes of healed shoulders after the arthroscopic-assisted modified Debeyre-Patte procedure were favorable. If the torn rotator cuff stump is retracted near the glenoid fossa, and the rotator cuff muscle scored Goutallier grade 3 or lower, this modified Debeyre-Patte procedure would be a viable option.

New quantitative ultrasound techniques for bone analysis at the distal radius in hip fracture cases: differences between femoral neck and trochanteric fractures.

BACKGROUND: Ample evidence on etiological and pathological differences between femoral neck and trochanteric fracture cases suggests the possibility of individualized treatment. There are many issues related to areal bone mineral density and other quantitative computed tomography parameters of the proximal femur. Although osteoporosis is a systemic problem, little has been reported regarding differences in bone structural parameters, including bone mineral density, between them in regions other than the proximal femur. METHODS: Participants were consecutive female patients >50 years of age admitted to the Saiseikai Suita Hospital (Osaka prefecture, Japan) for their first hip fracture between January 2012 and September 2014. Cortical thickness (CoTh, mm), volumetric trabecular bone mineral density (TBD, mg/cm3), and elastic modulus of trabecular bone (EMTb, GPa) were obtained as the new QUS parameters using the LD-100 system (Oyo Electric, Kyoto, Japan). The mean values of these parameters were compared between femoral neck and trochanteric fracture cases. In addition, correlations between age and each QUS parameter were investigated for each fracture type. A receiver operating characteristic (ROC) curve analysis was performed to examine the degree of effect each parameter on the fracture types. The area under the curve (AUC) for each parameter was compared to the AUC for age. RESULTS: There were 63 cases of femoral neck fracture (mean age, 78.2 years) and 37 cases of trochanteric fracture (mean age, 85.9 years). Mean TBD and EMTb were significantly higher for femoral neck fractures. There were significant negative correlations between QUS parameters and age for femoral neck fractures (P < 0.005). The regression lines for femoral neck fractures were above those for trochanteric fractures for TBD and EMTb. AUCs were 0.72 for age, and 0.61, 0.65, and 0.65 for CoTh, TBD, and EMTb, respectively. CONCLUSIONS: The new QUS parameters indicated that TR fracture cases were more osteoporotic than were FN fracture cases, even at the distal radius. There might be systemic differences between them, in addition to localized factors at the proximal femur.

Association between loss of bone mass due to short sleep and leptin-sympathetic nervous system activity.

BACKGROUND: Sleep has been reported to be an important factor in bone metabolism, and sympathetic nervous system activity has been reported to regulate bone metabolism. In this study, we evaluated the association between sleep, sympathetic nervous system activity, and bone mass. METHODS: The study subjects were 221 individuals (108 males; 113 females; mean age: 55.1±7.0years) divided into two groups: those who slept for less than 6h a day (short sleep [SS] group), and those who slept 6h or longer (normal sleep [NS] group). The groups were compared with regard to lifestyle, cortical bone thickness, cancellous bone density, bone metabolism markers, blood leptin levels, and sympathetic nervous system activity as evaluated by heart rate variability analysis. RESULTS: Significant differences were observed between the two groups in cortical bone thickness, blood TRACP-5b, and leptin levels. The L/H ratio (an index of sympathetic nervous system activity) was higher in the SS group than in the NS group. Significant negative correlations were observed between cortical bone thickness and both the L/H ratio and leptin levels, and a significant positive correlation was observed between the L/H ratio and leptin levels. CONCLUSIONS: Short sleep was associated with a decline in cortical bone thickness due to the promotion of bone resorption and sympathetic nervous system hyperactivity in the middle-aged group. Leptin levels and cortical bone thickness were found to be closely related, suggesting that cortical bone mass may be regulated via interaction with the leptin-sympathetic nervous system.

Characteristics of donor and host cells in the early remodeling process after transplant of Achilles tendon with and without live cells for the treatment of rotator cuff defect--what is the ideal graft for the treatment of massive rotator cuff defects?

PURPOSE: We examined the characteristics of donor and host cells in the early remodeling process after transplant of Achilles tendon with and without live cells to repair rotator cuff defects. We also clarified which graft with or without live cells was superior in the early remodeling process. MATERIALS AND METHODS: Sprague-Dawley (SD) rats and green fluorescent protein (GFP) rats were used; they were divided into 3 groups: in group SD, the Achilles tendons of GFP rats were transplanted into the defects of SD rats; in group GFP, the Achilles tendons of SD rats were transplanted into GFP rats; in group GFP-Fr, frozen Achilles tendons of SD rats were transplanted into GFP rats. At 3 and 7 days after surgery, these sections were examined histologically and immunohistochemically with anti-heat shock protein (HSP) 47 and anti-macrophage antibodies. RESULTS: Donor cells gradually decreased, but HSP47-positive donor cells were detected at 3 days in group SD. Host cells infiltrated into the graft from the surrounding tissue, and their numbers in groups SD and GFP gradually increased more significantly than in group GFP-Fr. Macrophages derived from the donor tissue were absent in all groups. The remodeling process of the frozen graft was slower than that in the case of the graft that was not frozen. CONCLUSION: These results demonstrate that live donor cells have a positive effect on the remodeling process. Therefore, autografts with live cells considered to be preferred to frozen allografts or synthetic materials without live cells for transplant for rotator cuff defects.

Behavior of host and graft cells in the early remodeling process of rotator cuff defects in a transgenic animal model.

Autologous tissue graft is one of the treatment options for a large rotator cuff defect. To develop appropriate strategies for enhanced solid graft integration at the bone-tendon interface and tendon-tendon interface, clarifying the fate of the graft and host cells that contribute to repair and remodeling is necessary. We have developed a new grafting model using green fluorescent protein-transgenic rats and wild-type rats to simulate autologous transplantation for examining the behavior of the host and graft cells in the remodeling process after tendon grafting. We found that the host cells commenced proliferation in the graft at 1 day after grafting. The host cells infiltrated into the graft from the subacromial synovium, proximal tendon, and bone-tendon insertion. The number of graft-derived cells decreased with time. Our result clearly demonstrated that host cells, rather than graft cells, were essential for rotator cuff remodeling after tendon grafting for rotator cuff defect.

Magnetic resonance imaging evaluation of the inferior glenohumeral ligament: non-arthrographic imaging in abduction and external rotation.

The anterior band of the inferior glenohumeral ligament is the most important restraint for preventing traumatic anterior glenohumeral instability. The condition of this ligament markedly affects the results of arthroscopic Bankart repair. We compared non-arthrographic magnetic resonance imaging (MRI) in abduction and external rotation and arthroscopic findings of the ligament in 51 shoulders with traumatic anterior glenohumeral instability. The condition of the ligament was evaluated based on the presence of a thick low-signal band between the anterior labrum and the head of the humerus in all magnetic resonance images obtained from the 3- to 5-o'clock position of the glenoid rim (right shoulder). The sensitivity and specificity of the MRI evaluation were 94% and 82%, respectively. MRI in abduction and external rotation is fairly useful for predicting the condition of the ligament in advance of invasive measures (ie, arthroscopy).

Newly devised anterior portal technique for arthroscopic bankart repair using suture anchors.

Many techniques and instrument systems have been developed for performing arthroscopic Bankart repair using a suture anchor. The suture anchor procedure relies on a secure knot, which does not become entangled in the anterior portal. A newly devised anterior portal technique can solve this problem. We have used this technique for arthroscopic Bankart repair using suture anchor. This technique may be useful for any type of suture materials such as SLAP lesion.