Construction of ceRNA regulatory networks for osteoporosis.

Osteoporosis increases the risk of fracture. Improving the diagnosis and treatment of osteoporosis has clinical applications. The differentially expressed genes (DEcircRs, DEmRs, DEmiRs) of osteoporotic patients and controls were analyzed using the GEO database, and enrichment analysis of DEmRs was performed. circRNAs and mRNAs, which were predicted to have a target relationship with DEmRs, were obtained to compare competing endogenous RNA (ceRNA) regulatory networks by comparison with differentially expressed genes. Molecular experiments were utilized to validate the expression of genes within the network. The interactions between genes within the ceRNA network were validated by luciferase reporter assays. Following overexpression of circ_0070304 in bone marrow mesenchymal stem cells (BMSCs), the osteogenic differentiation of the cells was assessed by Alizarin Red staining. A total of 110 intersectional DEmRs between patients with osteoporosis and controls from GSE35958 and GSE56815, which were mainly enriched in estrogen, the thyroid hormone signaling pathway, and adherens junctions were identified. A ceRNA network [circ_0070304/miR­183­5p/ring finger and CCCH­type domains 2 (RC3H2)] was then constructed. Circ_0070304 acted as a sponge for miR­183­5p and regulated RC3H2 expression. Overexpression of circ_0070304 upregulated ROCK1 and induced osteogenic differentiation. The ceRNA regulatory network that was obtained is expected to be a new target for osteoporosis treatment and to provide new insights into the diagnosis and treatment of osteoporosis in greater depth.

Dose-Effectiveness Relationships Determining the Efficacy of Ibandronate for Management of Osteoporosis: A Meta-Analysis.

The purpose of this study was to perform a meta-analysis on the efficacy of ibandronate by evaluating the effect sizes of different dosing regimens.Major electronic databases were searched from 1985 to February 2015. A random effects meta-analysis was performed in STATA.Data from 34 studies (13,639 patients) were included in this meta-analysis. Ibandronate treatment significantly improved lumbar spine bone mineral density (BMD) as shown by the percent change from baseline (4.80%, P < 0.0001, 95% confidence interval [CI] [4.14, 5.45]). The respective effect sizes for oral intake and intravenous (IV) infusion were 4.57% and 5.22% (P < 0.0001, CIs [3.71, 5.42] and [4.37, 6.07]), respectively. All doses led to a significant increase in BMD except 2 oral dose regimens (1 mg/d: 4.65%, P = 0.285, 95% CI [-3.87, 13.18] and 0.5 mg/d: 3.60%, P = 0.38, 95% CI [-4.43, 11.64]. Ibandronate treatment (overall as well as dose wise) also significantly improved the total hip BMD-2.30% overall, 2.13% oral, and 2.63% IV (P < 0.0001, 95% CIs [1.96, 2.64], [1.70, 2.55], and [2.07, 3.20]), respectively. Ibandronate administration significantly decreased serum markers of bone resorption to -46.53% for C-terminal telopeptide of type 1 collagen, -24.03% for bone-specific alkaline phosphatase, and -50.17% for procollagen type I N-terminal propeptide (P < 0.0001, 95% CIs [-53.16, -39.91], [-31.28, -16.77], and [-64.13, -36.20]), respectively. Parathyroid hormone levels remained unaffected by ibandronate treatment (3.03%, P = 0.439, 95% CI [-5.06, 11.66]).There was no significant difference in the efficacy of ibandronate between oral or IV administration. Predominant dose regimens for IV administration were 1 to 3 mg/3 mo and 150 mg/mo oral and 2.5 mg/d for oral ibandronate treatment.

Autophagy genes associated with chondrocyte apoptosis: protection and balancing effects / 中国组织工程研究

BACKGROUND:Autophagy can occur in chondrocytes under the low supply of nutrients. Different from necrosis and apoptosis, autophagy can make chondrocytes survive in insufficient supply of nutrients, which may be an important mechanism for the self-protection of chondrocytes. OBJECTIVE: To review the mechanism and effect of autophagy gene to protect the articular cartilage and inhibit osteoarthritis. METHODS:A computer-based search was perform in CNKI, Wanfang, PubMed to retrieve articles addressing autophagy gene and osteoarthritis published from January 2000 to January 2015. The keywords were autophagy, osteoarthritis, articular cartilage, chondrocytes in Chinese and autophagy, osteoarthritis, beclin1, LC3 in English. Totaly 269 articles were initialy searched, and finaly, 38 articles were included in result analysis. RESULTS AND CONCLUSION:Apoptosis of damaged chondrocytes is the main mechanism of articular cartilage degeneration, which can further develop into osteoarthritis. The damage and death of cels is one of the important mechanisms of cartilage degeneration, thus, to prevent damaged chondrocyte apoptosis may help cartilage repair, thus aleviating the progression of osteoarthritis. Autophagy can inhibit damaged chondrocyte apoptosis, which changes the limitations of traditional treatments for osteoarthritis. However, the current research on autophagy genes associated with osteoarthritis is stil at the primary stage, and further studies are needed on how to induce authopagy pathway in the cartilage, how to do the signal transduction and how to have an effect on the survival of chondrocytes.

Autophagy effects on chondrocyte survival and cartilage damage / 中国组织工程研究

BACKGROUND:Autophagy is the celular process of lysosomal pathway processing by endogenous substrates, which exists in the body cels and has been considered as type II programmed cel death. Autophagy may be a protective or balancing mechanism of normal chondrocytes. OBJECTIVE:To discuss the latest research progress in autophagy and cartilage damage aiming to better understanding the role of autophagy in cartilage damage and repair. METHODS:A computer-based search of CNKI, Wanfang database and PubMed database was performed for articles relevant to autophagy and cartilage damage published in recent 20 years with the key words of autophagy, cartilage, chondrocytes, beclin1, LC3 in Chinese and English. RESULTS AND CONCLUSION: Intra-articular chondrocytes can response to the changes in the microenvironment so as to adjust the extracelular matrix metabolism and maintain the biological function of articular cartilage. Hypoxic environment in which chondrocytes eixt is an important factor to causes autophagy. Autophagy is a normal balance or protection mechanism of chondrocytes. Studies on the correlation of autophagy with cartilage damage have made considerable progress in recent years, but stil in its infancy. Atg discovery at the molecular level deepens the understanding of autophagy, but the induction of cartilage autophagy pathway, signal transduction, and their effects on the survival of chondrocytes are not clear yet, which need further studies.

Flurbiprofen axetil for damage control in rat models of hip fractures：reducing inflammatory responses / 中国组织工程研究

BACKGROUND:Since damage control theory system was founded, this theory in the orthopedics has been applied gradualy, especialy in elderly hip fracture surgery that reduces the negative impacts due to inflammatory responses. OBJECTIVE:To explore whether flurbiprofen axetil can reduce inflammatory responses in rats with hip fractures based on the damage control theory. METHODS: Forty-nine healthy Sprague-Dawley rats weighing 250-300 g were randomly divided into four groups:control group (n=7), immediate internal fixation group (n=14), flurbiprofen axetil group (n=14), damage control group (n=14). Rats in the control group moved freely in the cages. Rats in the other three groups were intraperitonealy injected with composite anesthetics to make unilateral hip fracture models, and then respectively given internal fixation immediately after fracture, flurbiprofen axetil injection and delayed internal fixation, and delayed internal fixation. Levels of serum C-reactive protein, interleukin-6 and tumor necrosis factor-α were determined and analyzed before fixation, immediately after internal fixation and at 4, 8, 12, 24, 48 hours after internal fixation in different groups. RESULTS AND CONCLUSION:Postoperative serum levels of C-reactive protein, interleukin-6, tumor necrosis factor-αwere al increased in different groups. The level of C-reactive protein reached the peak at 24 hours after internal fixation. Flurbiprofen axetil injection had no significant influence on the level of C-reactive protein in rats with delayed internal fixation (P=0.51). Interleukin-6 levels were stil increased at 48 hours after internal fixation, but flurbiprofen axetil reduced the level of interleukin-6 significantly in rats with delayed internal fixation (P < 0.01). The tumor necrosis factor-α level peaked at 4 hours after internal fixation, and flurbiprofen axetil injection could significantly reduce the level of tumor necrosis factor-α in rats with delayed internal fixation (P < 0.01). These findings indicate that flurbiprofen axetil as a new non-steroidal anti-inflammatory drug can reduce the inflammatory response in rats with hip fractures after internal fixation, and also can aleviate the inflammatory response of rats undergoing delayed operation under the guidance of damage control theory.

Functional status of bone marrow mesenchymal stem cells from osteoarthritis patients and disease development / 中国组织工程研究

BACKGROUND:Bone marrow mesenchymal stem cels are crucial for bone and cartilage development and regeneration at a celular level. Insufficient quantity and functional impairment of bone marrow mesenchymal stem cels is widely considered to be one of osteoarthritis causes. OBJECTIVE: To explore the relationship between the functional status of bone marrow mesenchymal stem cels and disease progression in osteoarthritis patients.METHODS: Thirty patients with osteoarthritis were enroled from July 2013 to October 2014, and divided into control, mild osteoarthritis, and severe osteoarthritis groups, with 10 cases in each group. 5 mL bone marrow from the femur or tibia was extracted from each patient to isolate and culture bone marrow mesenchymal stem cels. Proliferation ability of cels at passage 3 was detected using cel counting kit-8; toluidine blue staining was performed at 14 days after chondrogenic induction; real-time PCR was used to detect the mRNA expression of Aggrecan and Col2A1 in the control group after chondrogenic induction. RESULTS AND CONCLUSION:Afterin vitro culture, bone marrow mesenchymal stem cels grew adherently in polygonal and fusiform shape with multiple processes at uniform size. The cytoplasm contained larger particles and the nuclei were ovoid. Most of cels were in cel division phase. The proliferation ability was strongest in the control group and weakest in the severe osteoarthritis group. Cels from the three groups were al at plateau phase after 1 week culture. At 14 days after chondrogenic induction, the cels were polygonal and quasi-circular, and purple metachromatic granules distributed outside of the cytoplasm. The expression of Aggrecan and Col2A1 in the control group displayed an overexpression trend. These findings indicate that the functional status of bone marrow mesenchymal stem cels from osteoarthritis patients is negatively correlated with the severity of disease, which can influence the disease progression in osteoarthritis patients.

Inflammatory transmitter changes during tourniquet-induced limb ischemia-reperfusion injury and the role of ischemic preconditioning / 中国组织工程研究

BACKGROUND:Over-expression of serum interleukin-6 and interleukin-8 may be involved in tourniquet-induced limb ischemia-reperfusion injury to the lung ventilation function. OBJECTIVE:To evaluate the tourniquet effect on serum interleukin-6 and interleukin-8 levels of the rat limb within the safety time limit. METHODS: Sixty rats were randomly divided into control and experimental groups, 30 rats in each group. Rats in the control group had no ischemic preconditioning and were directly subjected to stop bleeding for 2, 3, 4 hours; rats in the experimental group were subjected to ischemic preconditioning (short-time hemostasis for several times within 1 day before ischemia-reperfusion injury), and then underwent 2-, 3-, 4-hour hemostasis at the 2nd day. At 1, 3, 7, 14 days after the recovery of limb blood flow, blood samples were extracted to detect serum interleukin-6 and interleukin-8 levels using ELISA method. RESULTS AND CONCLUSION:The levels of interleukin-6 interleukin-8 showed an increasing and decreasing trend in the two groups, which both reached the peak at the 3rd day (P 0.05), and at 3, 7, 14 days, the level of interleukin-8 in the rats undergoing 4-hour hemostasis was significantly higher than that in the control group (P< 0.05). At 1 and 3 days, the levels of interleukin-6 and interleukin-8 in the experimental group had an increasing trend with the bleeding time and ranked as folows: 2-hour hemostasis < 3-hour hemostasis < 4-hour hemostasis, and there was a significant difference; while in the control group, there was also an increasing trend in the levels of interleukin-6 and interleukin-8, but there was no statistical difference. These findings indicate that the tourniquet preconditioning treatment is preferred at 3 days after limb ischemia-reperfusion injury, when the inflammatory response was the most obvious in rats, and this treatment can dramaticaly reduce inflammatory response. Additionaly, the inflammatory become more obvious with the bleeding time.

Bone marrow mesenchymal stem cells are induced directly to differentiate into chondrocytes in osteoarthritis patients / 中国组织工程研究

BACKGROUND:In recent years, many reports have focused on inflammatory cytokines, growth factors and mechanical loads affecting the cartilage and subchondral regeneration, but there is a lack of comprehensive understanding about the mechanism of osteoarthritis. OBJECTIVE: To explore the correlation between function status of bone marrow mesenchymal stem cels and disease progression in patients with osteoarthritis. METHODS:Femoral bone marrow was extracted from patients with femoral neck fractures (control group), mild (mild group) and severe (severe group) osteoarthritis to isolate and culture bone marrow mesenchymal stem cels. Cel counting kit-8 was used to detect the proliferative ability of bone marrow mesenchymal stem cels from different patient groups, and passage 3 bone marrow mesenchymal stem cels were subject to 2-week chondrogenic induction folowed by toluidine blue staining. RESULTS AND CONCLUSION: Bone marrow mesenchymal stem cels were isolated and cultured from the femoral bone marrow of different groups. The proliferative ability of cels in the control group was significantly higher than that in the mild and severe groups. After chondrogenic induction, bone marrow mesenchymal stem cels varied obviously in the morphology that was from fusiform to qusi-circular or polygon, the percentage of nucleoplasm became smaler, and cels were positive for toluidine blue staining. The number of chondrocytes generated in the severe group was less than that in the control group, but there was no great difference in cel morphology. These findings indicate that the occurrence of osteoarthritis is negatively correlated with the functional status of autologous bone marrow mesenchymal stem cels.

Effect of an anterior glenoid defect on anterior shoulder stability: a cadaveric study.

BACKGROUND: There have been few biomechanical studies to clarify which size of a glenoid defect is critical. However, those studies have assumed that the defect occurred anteroinferiorly. Recent studies have reported that the defect is located anteriorly rather than anteroinferiorly. Therefore, the effect of the anterior, not anteroinferior, glenoid defect on shoulder stability needs to be investigated. HYPOTHESIS: The anterior glenoid defect would have a similar effect on anterior shoulder stability as that of the anteroinferior glenoid defect. STUDY DESIGN: Controlled laboratory study. METHODS: Eight fresh-frozen cadaveric shoulders were used (mean age, 74 years). The specimen was attached to a shoulder-testing device with the arm in abduction and external rotation. An osseous defect was created stepwise with a 2-mm increment of the defect width. The stability ratio was used to evaluate joint stability. With a 50-N axial force, the translational force applied to the humeral head was measured by a force transducer. RESULTS: The stability ratio without a defect (32% +/- 6%) significantly decreased after creating a 6-mm defect (17% +/- 5%; P = .0001), which was equivalent to 20% of the glenoid length. CONCLUSION: An osseous defect at 3 o'clock with a width that was equal to or greater than 20% of the glenoid length significantly decreased anterior stability. CLINICAL RELEVANCE: The results suggest that reconstruction of the glenoid concavity might be necessary in shoulders with an anterior glenoid defect of at least 20% of the glenoid length.

Location of the Hill-Sachs lesion in shoulders with recurrent anterior dislocation.

INTRODUCTION: Computed tomography images of 35 shoulders of 34 patients with recurrent anterior dislocation and 13 shoulders of 13 healthy normal volunteers were used to determine the location of the Hill-Sachs lesion in reference to the location of the bare area using computed tomography. METHOD: We measured the location, and size of the Hill-Sachs lesion and the bare area, and described them on a clock face on the humeral head. RESULTS: The Hill-Sachs lesion was observed in slices between 0-3 and 22-24 mm distal from the top of the humeral head. The bare area was located only in slices 19-21 mm and below. CONCLUSION: From these data, we concluded that the Hill-Sachs lesion exists in the area between 0 and 24 mm from the top of the humeral head, and the inferior portion of the Hill-Sachs lesion overlaps the bare area if it extends beyond 19 mm from the top of the humeral head.

Glenohumeral joint motion after medial shift of the attachment site of the supraspinatus tendon: a cadaveric study.

During a rotator cuff repair, it is ideal to reattach the torn edge of the cuff tendon back to the greater tuberosity. However, with massive tears where the torn edges are too retracted to be reattached to the greater tuberosity, they may have to be reattached somewhere more medial. It is clinically important to know how far medially one can shift the reattachment site without sacrificing function of the shoulder. Ten fresh, previously-frozen cadaveric shoulders were used. Medial shift of the supraspinatus tendon was simulated by placing the suture anchors along lines 3, 10, or 17 mm medial to the cuff attachment site. The ranges of glenohumeral motion were measured using a goniometer with a constant torque applied to the humerus. All motions, except for internal rotation at 60 degrees of abduction, were significantly restricted by medial shift of 10 mm or more compared with that of the intact shoulder. We conclude that significant restriction of joint motion occurs when a bony trough is created more than 10 mm medial to the cuff attachment site.

Effect of rotator interval closure on glenohumeral stability and motion: a cadaveric study.

The effect of rotator interval closure, which is performed as an adjunct to arthroscopic stabilization of the shoulder, has not been clarified. Fourteen fresh-frozen cadaveric shoulders were used. The position of the humeral head was measured using an electromagnetic tracking device with the capsule intact, sectioned, and imbricated between the superior glenohumeral ligament and the subscapularis tendon (SGHL/SSC closure) or between the superior and middle glenohumeral ligaments (SGHL/MGHL closure). The direction of translational loads (10, 20, and 30 N) and arm positions were (1) anterior, posterior, and inferior loads in adduction; (2) anterior load in abduction/external rotation in the scapular plane; and (3) anterior load in abduction/external rotation in the coronal plane. The range of motion was measured using a goniometer under a constant force. Both methods reduced anterior translation in adduction. Only SGHL/MGHL closure reduced anterior translation in abduction/external rotation in the scapular plane and posterior translation in adduction. Both methods reduced the range of external rotation and horizontal abduction. Rotator interval closure is expected to reduce remnant anterior/posterior instability and thereby improve the clinical outcomes of arthroscopic stabilization procedures.

Expression of growth factors in the early phase of supraspinatus tendon healing in rabbits.

Growth factors are known to appear during wound healing. We hypothesized that growth factors would also appear during the healing process of a rotator cuff tear. We determined the expression of various growth factors during healing of acute rotator cuff tears in the rabbit. We made a full-thickness defect in the supraspinatus tendon of 27 Japanese white rabbits. The shoulders were harvested on days 1, 3, 5, 7, 9, 11, 14, 21, and 28 postoperatively (n = 3 at each time point). We assessed the expression of basic fibroblast growth factor, insulin-like growth factor 1, platelet-derived growth factor, and transforming growth factor beta. Basic fibroblast growth factor appeared with its peak on days 7 and 9, insulin-like growth factor 1 appeared with its peak on day 5, platelet-derived growth factor appeared with a mild expression between days 7 and 14, and transforming growth factor beta appeared with constant mild expression throughout the observation period. It is likely that each of these growth factors plays a role in the early phase of healing of the supraspinatus tendon in rabbits.

The effect of the inferior capsular shift on shoulder intra-articular pressure: a cadaveric study.

BACKGROUND: The inferior capsular shift procedure is commonly performed for multidirectional instability of the shoulder with excellent clinical results. HYPOTHESIS: The mechanism of this procedure is to increase shoulder stability by changing the responsiveness of intra-articular pressure to downward loading. STUDY DESIGN: Controlled laboratory study. METHODS: In 7 fresh-frozen cadaveric shoulders, inferior capsular shift was simulated by imbricating the anterior and posterior capsule using clamps. The position was monitored using an electromagnetic tracking device with the glenohumeral joint capsule intact, imbricated anteriorly, or imbricated anteriorly and posteriorly and with the inferior load of 0, 0.5, or 1.0 kg. Simultaneously, intra-articular pressure was monitored using a pressure transducer. Saline was injected into the glenohumeral joint to measure capsular volume. The capsule was vented, and the position was again measured. RESULTS: Intra-articular pressure was -71 +/- 19, -221 +/- 70, and -366 +/- 73 cm H(2)O with 0, 0.5, and 1.0 kg of load, respectively, with the capsule intact. With anterior imbrication, intra-articular pressure decreased to -79 +/- 10, -274 +/- 103, and -460 +/- 135 cm H(2)O, respectively, and with anterior and posterior imbrication, intra-articular pressure further decreased to -87 +/- 16, -308 +/- 74, and -548 +/- 39 cm H(2)O, respectively. The volume of the intact shoulder (36 +/- 9 mL) significantly decreased to 27 +/- 7 mL (75%) with anterior imbrication and to 15 +/- 5 mL (42%) with anterior and posterior imbrications (P = .0001). Before venting the capsule, inferior displacement was 5% of the vertical length of the glenoid, even with 1.0 kg of load with any capsular conditions. After venting, the humeral head dislocated inferiorly in all shoulders, even after imbrications. CONCLUSION: The inferior capsular shift procedure decreases joint volume and increases responsiveness of intra-articular pressure to downward loading. CLINICAL RELEVANCE: Biomechanical data provide scientific background to the commonly performed procedures of inferior capsular shift and thermal capsular shrinkage.

Apoptosis in the supraspinatus tendon with stage II subacromial impingement.

The purpose of this study was to investigate the histopathology, including apoptosis, in the supraspinatus tendon with stage II subacromial impingement. Samples from the critical zone of the supraspinatus tendon were obtained from 5 patients with subacromial impingement syndrome and 10 autopsy cases without shoulder diseases as controls. Three-micrometer-thick sections were cut and stained with hematoxylin-eosin (H-E) for routine histologic examination. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method and single-stranded deoxyribonucleic acid (ssDNA) assay in which the frequency of the apoptotic cells was expressed by the apoptotic index. Control supraspinatus tendons showed normal morphology, whereas supraspinatus tendons from shoulders with impingement showed significant mucoid degeneration. Correspondingly, few apoptotic cells were observed in control tendons, whereas a large number of apoptotic cells were observed in the degenerative area of tendons from impingement shoulders. The apoptotic indices were significantly higher in the impingement shoulders (ssDNA, 18.84% +/- 1.75%; TUNEL, 24.92% +/- 2.79%) than in the control shoulders (ssDNA, 5.22% +/- 1.30%; TUNEL, 7.01% +/- 1.05%) (P = .04 for ssDNA and P = .017 for TUNEL). Mechanical impingement seems to cause tendon degeneration and apoptosis of the tendon cells in the supraspinatus tendon in stage II impingement.

Cross-sectional area of the tendon and the muscle of the biceps brachii in shoulders with rotator cuff tears: a study of 14 cadaveric shoulders.

BACKGROUND: The intraarticular portion of the long head of the biceps tendon is often widened in shoulders with cuff tears. It is unclear whether this is a local phenomen or is caused by muscle hypertrophy. METHODS: We investigated morphological changes of the biceps brachii in 14 embalmed shoulders: 7 with intact rotator cuff and 7 with rotator cuff tears. We measured the cross-sectional area (CSA) of the tendon of the long head of the biceps (LHB) at 9 levels between the glenoid origin and the musculotendinous junction. The muscle volume and the muscle fiber length of the long and short heads of the biceps were measured to calculate the physiological CSA (PCSA) by dividing the volume by the fiber length. RESULTS: The CSA of the LHB tendon at the entrance to the bicipital groove was greater in cuff tear shoulders than in normal shoulders. The PCSA of the biceps was similar in normal and cuff tear shoulders. INTERPRETATION: Hypertrophy of the LHB tendon appears to be a localized morphological change near the entrance to the bicipital groove.

Attachment types of the long head of the biceps tendon to the glenoid labrum and their relationships with the glenohumeral ligaments.

PURPOSE: To clarify the attachment types of the long head of the biceps tendon to the glenoid labrum and their relationships with the glenoid attachment of the glenohumeral ligaments. TYPES OF STUDY: Anatomic study in cadavers. METHODS: Using 101 cadaver shoulders, the glenoid attachment types of the biceps tendon and the location of the glenoid origin of the glenohumeral ligaments were assessed macroscopically and then histologically on the sagittal section. RESULTS: The glenoid attachment types of the biceps tendon were defined as entirely-posterior in 28 shoulders (27.7%), posterior-dominant in 56 shoulders (55.4%), equal in 17 shoulders (16.8%), and entirely anterior in none (0%). In all shoulders, the superior and middle glenohumeral ligaments were attached between 12 and 1 o'clock (average, 12:36 o'clock), whereas the inferior glenohumeral ligament (IGHL) showed greater variation. In the posterior-dominant and equal types, the IGHL was attached relatively high (average 2:49 o'clock for the posterior-dominant type and 1:49 o'clock for the equal type). In the entirely posterior type, the IGHL was attached low, between 4 and 5 o'clock (average, 4:32 o'clock). There was a significant difference between them (P < .001). Histologic examination showed that in the posterior-dominant and equal types, the fibers of the IGHL directly linked to the fibers of the biceps tendon, whereas in the entirely posterior type no such direct connections were observed. However, in all types, the fibers of the biceps tendon were attached to the posterior labrum. CONCLUSIONS: The labral attachment of the long head of biceps tendon was posterior regardless of its macroscopic appearance. The macroscopic attachment pattern of the biceps tendon resulted from the different attachment height of the IGHL. The attachment site of the IGHL is lower than 4 o'clock in the entirely posterior type, whereas it is higher than 4 o'clock in other types. CLINICAL RELEVANCE: The present study provides useful information about the original attachment site of the IGHL during Bankart repair.

Contact area, contact pressure, and pressure patterns of the tendon-bone interface after rotator cuff repair.

BACKGROUND: The contact pressure and contact area at the tendon-bone interface after the most commonly used rotator cuff repair methods have not been investigated. HYPOTHESIS: There are no significant differences among the transosseous, the single-row suture anchor, and the double-row suture anchor techniques in terms of contact pressure, contact area, and pressure patterns at the tendon-bone interface. STUDY DESIGN: Controlled laboratory study. METHODS: After creating a full-thickness supraspinatus tendon tear in 10 cadaveric shoulder specimens, we inserted pressure-sensitive film between the tendon stump and the bone, and we repaired the tear by (1) transosseous, (2) single-row suture anchor, and (3) double-row suture anchor techniques. RESULTS: The contact area of the double-row technique was 42% greater than that of the transosseous technique (P < .0001) and 60% greater than that of the single-row technique. The contact area of the transosseous technique was 31% greater than that of the single-row technique (P = .0015). The average pressures of the single-row and double-row techniques were 18% (P = .014) and 16% (P = .03) greater, respectively, than that of the transosseous technique, but there was no significant difference between the single-row and double-row techniques (P = .915). CONCLUSIONS: The double-row technique produced the greatest contact area and the second-highest contact pressure, whereas the single-row technique created the highest contact pressure and the least contact area. The transosseous technique produced the second-greatest contact area and the least contact pressure. CLINICAL RELEVANCE: The double-row suture anchor technique and the transosseous technique may provide a better environment for tendon healing.

Location of the glenoid defect in shoulders with recurrent anterior dislocation.

BACKGROUND: In patients with recurrent anterior dislocations of the shoulder, it is well known that the glenoid rim is often deficient (8%-95%). However, little is known regarding the precise location of the bony defect of the glenoid. HYPOTHESIS: The bony defect is anterior rather than anteroinferior to the glenoid. STUDY DESIGN: Cohort study (symptom prevalence); Level of evidence, 2. METHODS: The authors studied 3-dimensional images of the glenoid reconstructed from computed tomography to determine the location of the glenoid defect in 123 shoulders of 123 patients with recurrent anterior dislocations of the shoulder. They measured the location, extent, and orientation of the defect based on the clock face of the glenoid. RESULTS: The defects were located between 12:08 and 6:32, with the range between 2:30 and 4:20 being the most frequent. The extent of the glenoid defect was 106.7 degrees +/- 27.1 degrees (mean +/- standard deviation). The mean orientation of the defect was pointing toward 3:01 on the clock face of the glenoid, at a mean angle of 90.5 degrees +/- 10.4 degrees from the 12-o'clock direction. CONCLUSION: The glenoid defect is located almost anterior to the glenoid.

Quantitative assessment of thinning of the subscapularis tendon in recurrent anterior dislocation of the shoulder by use of magnetic resonance imaging.

It is known that thinning and lengthening of the subscapularis tendon occur in shoulders with recurrent anterior dislocation. However, no studies have been performed to quantify the morphologic changes of the subscapularis tendon under such conditions. We retrospectively measured the thickness and cross-sectional area of the subscapularis tendon by use of magnetic resonance imaging in 22 shoulders in 11 patients with unilateral recurrent anterior dislocation of the shoulder. The contralateral shoulder in each patient served as a control. The thickness and cross-sectional area of the subscapularis on the affected side were smaller than those on the normal side (6.5 +/- 1.7 mm vs 8.0 +/- 1.9 mm, P = .001, and 388.6 +/- 120.0 mm 2 vs 547.9 +/- 128.5 mm 2 , P = .0001, respectively). We conclude that the subscapularis tendon undergoes an 18.7% decrease in thickness and a 29.1% decrease in cross-sectional area in shoulders with recurrent anterior dislocation.