Location and size of the reverse Hill-Sachs lesion in patients with traumatic posterior shoulder instability.

BACKGROUND: In patients with traumatic posterior shoulder instability, little is known about the precise location and size of the reverse Hill-Sachs lesion. METHODS: Forty-nine shoulders of 47 patients with traumatic posterior instability were included in this study based on the following inclusion criteria: (1) a primary or recurrent traumatic posterior shoulder dislocation and (2) the initial event being caused by trauma. Patients were excluded if they had (1) no history of trauma, (2) prior shoulder surgery, (3) no computed tomographic (CT) examination, or (4) were seizure cases. Three-dimensional images of the humerus reconstructed from CT images were reviewed using an image analysis software. The location and size of the reverse Hill-Sachs lesion were measured and described on a clock face on the humeral head. RESULTS: The reverse Hill-Sachs lesion was observed in 25 of 49 shoulders (51%). The reverse Hill-Sachs lesions were located between 1:37 and 2:48. The depth of the reverse Hill-Sachs lesion (mean ± standard deviation) was 5.8 ± 2.2 mm. The extent of the reverse Hill-Sachs lesion was 35° ± 12°. The average orientation of the reverse Hill-Sachs lesion, represented by an angle measured from the 12 o'clock position, was 64° ± 12° and pointing toward 2:09 on a clock face. The mean length and width of reverse Hill-Sachs lesions were 9.7 ± 4.7 mm and 11.1 ± 3.6 mm, respectively. CONCLUSION: The reverse Hill-Sachs lesion was a semicircular compression fracture located on the anteromedial aspect of the humeral head. Compared with shoulders with anterior shoulder instability, the humeral defect was smaller and located more inferiorly in shoulders with posterior instability.

Effects of shoulder abduction on the stiffness of supraspinatus muscle regions in rotator cuff tear.

This study aimed to compare the effect of the load of the upper limb on the stiffness of supraspinatus muscle regions during isometric shoulder abduction in the scapular plane in healthy individuals and patients with a rotator cuff tear. Thirteen male patients were scheduled for arthroscopic rotator cuff repair, and 13 healthy male individuals were recruited. The movement task involved 30° isometric shoulder abduction in the scapular plane. The tasks included passive abduction, abduction with half-weight of the upper limb (1/2-weight), and full weight of the upper limb (full-weight). The stiffness of the supraspinatus muscle (anterior superficial, anterior deep, posterior superficial, and posterior deep regions) was recorded using ultrasound shear-wave elastography. The stiffness of the anterior superficial region on the affected side was significantly lower than that on the control side for the 1/2-weight and full-weight tasks. The stiffness of the anterior deep, posterior superficial, and posterior deep regions was not affected. This is the first study that investigated the mechanical effects of different loads on different supraspinatus muscle regions in rotator cuff tear patients. Our results indicate that the anterior superficial region in rotator cuff tear patients was mainly responsible for reduced active stiffness. This might be because this region contributes to force exertion and exhibits atrophy in rotator cuff tears. Hence, the anterior superficial region could be a focal point of quantitative dysfunction evaluation of the supraspinatus muscle in the case of a rotator cuff tear.

Arthroscopic superior capsule reconstruction with Teflon felt synthetic graft for irreparable massive rotator cuff tears: clinical and radiographic results at minimum 2-year follow-up.

BACKGROUND: Superior capsule reconstruction (SCR) was developed to improve shoulder function and relieve pain in patients with irreparable rotator cuff tears. Here, we investigated the clinical and radiographic outcomes and postoperative complications of SCR using a Teflon graft for reconstruction. METHODS: Thirty-five consecutive patients with irreparable rotator cuff tears underwent SCR with Teflon grafts. The American Shoulder and Elbow Surgeons score, active shoulder elevation, shoulder muscle strength, visual analog scale pain scores, acromiohumeral distance, and postoperative complications were investigated. Data obtained before and after surgery were compared by using a paired t-test, χ2 test, and 1-way analysis of variance, and data from 1-layer-graft SCR (15 patients; mean age, 75.1 years) and 3-layer-graft SCR (20 patients; mean age, 76.6 years) were compared by using an unpaired t-test. The average time to final follow-up was 42 months (range, 24-69 months). RESULTS: SCR using Teflon grafts of either 1 or 3 layers significantly improved the American Shoulder and Elbow Surgeons score (by 20.8, P = .001 for a 1-layer graft; and by 31.1, P < .0001 for a 3-layer graft), visual analog scale score for motion pain (by 3.2, P = .001; and by 3.0, P < .0001), and muscle strength in shoulder abduction (by 11.9 N, P = .02; and by 10.9 N, P = .008). Active elevation at final follow-up was significantly greater in the 3-layer-graft group (142° ± 27°) than in the 1-layer-graft group (107° ± 42°) (P = .006). One year after SCR, acromiohumeral distance in the 3-layer-graft group was significantly greater than preoperatively (P = .04), whereas in the 1-layer-graft group, it was not. On postoperative magnetic resonance imaging, none of the patients in the 3-layer-graft group had graft tears, whereas 2 patients had graft tears and 1 patient had severe synovitis after 1-layer-graft SCR. CONCLUSION: SCR using a Teflon graft-especially a 3-layer graft-significantly improved shoulder function and shoulder abduction strength, with pain relief and a low rate of postoperative complications. SCR using a Teflon graft can be a viable option for irreparable rotator cuff tears, especially when an autograft or allograft is not available.

Arthroscopic findings of traumatic first-time anterior shoulder instability: a comparison of adolescent versus adult patients.

Background: Recurrence rates after first-time shoulder dislocation in young patients are high, especially in their early teens. Only a few studies have arthroscopically investigated the inside of the glenohumeral joint in young patients. Such arthroscopic investigation would help in solving the cause of the greater incidence of recurrent instability in the young population, especially in their early teens. Methods: Data from 42 patients with first-time anterior shoulder dislocation were retrospectively reviewed. The participants were divided into two groups: those aged 10 to 15 years at the time of the dislocation (adolescent group) and those aged 20- 29 years (adult group). The arthroscopic findings regarding the glenohumeral joint in the adolescent group were assessed and compared to those in the adult group. The intra-articular pathology was examined in all cases and recorded with specific reference to (1) the anterior capsulolabral lesion, (2) Hill-Sachs lesion, (3) labrum-anteroinferior glenohumeral ligament complex, and (4) other concomitant lesions. Results: Anterior joint laxity was found more in the adolescent group than in the adult group (P = .046). Thirty-six (83%) shoulders had Hill-Sachs lesions: 6 shoulders (60%) in the adolescent group and 30 shoulders (97%) in the adult group, with a significant difference (P < .001). Conclusion: Pathological findings observed during arthroscopy are more common in the adult group, whereas recurrent instability is more likely in adolescent group.

Time-course changes in active stiffness of the supraspinatus muscle after arthroscopic rotator cuff repair.

PURPOSE: This study aimed to investigate the time-course changes in the active stiffness of the supraspinatus muscle after arthroscopic rotator cuff repair. METHODS: Eight male patients (mean age 61.5 ± 9.4 years) who underwent arthroscopic rotator cuff repair for small to medium tears were recruited for this study. Movement tasks included 30° shoulder isometric abduction and maximal voluntary isometric contraction of shoulder abduction in the scapular plane. The stiffness of the supraspinatus (anterior superficial, anterior deep, posterior superficial, and posterior deep regions), upper trapezius, and middle deltoid muscles in bilateral shoulders was recorded using ultrasound shear wave elastography. For each subject, the measurement was performed preoperatively and 3, 6, and 12 months postoperatively. RESULTS: The stiffness of the affected anterior superficial region of the supraspinatus muscle 12 months postoperatively was significantly higher than that measured preoperatively and 3 months postoperatively (p < 0.05); it was significantly higher at 6 months postoperatively than at 3 months postoperatively (p < 0.05). Further, the maximal voluntary isometric contraction had significantly improved 12 months postoperatively compared to that measured preoperatively and 3 months postoperatively (p < 0.05). The stiffness of the affected upper trapezius and middle deltoid muscles 12 months postoperatively was significantly lower than that preoperatively (p < 0.05). CONCLUSION: The maximal voluntary isometric contraction 12 months postoperatively possibly increased because of improvement in the active stiffness of the anterior superficial region. Active stiffness of the anterior superficial region may improve 6 months rather than 3 months postoperatively because of the different stages of muscle force, structural repair tendon strength, and remodeling.

Cable Graft: Simple Superior Capsule Reconstruction Technique for Irreparable Rotator Cuff Tear Using a Teflon Patch.

We describe a simple superior capsule reconstruction technique for irreparable rotator cuff tear using a Teflon patch. In this technique, a triple-folded Teflon patch, suture tape, and a strong suture penetrating through the graft are fixed to the glenoid and greater tuberosity using a suture anchor. This allows for reconstruction of the superior capsule while simultaneously playing a role as a spacer. This procedure's greatest advantage is its simplicity; it is easy to perform, has a short operative time, and avoids the need to collect autologous tissue. More time is saved, as suturing and tying are not required. We believe our study could aid orthopaedic surgeons in clinical decision-making when encountering irreparable rotator cuff repairs.

Bone union of the transferred coracoid graft is the key factor affecting the extent of postoperative graft changes and the clinical results following the modified Bankart and Bristow procedure: a computed tomography scan study.

BACKGROUND: The extent of postoperative changes in the coracoid process grafted during the modified Bankart and Bristow procedure remains unclear. The purpose of the present study was to quantify the postoperative changes in bone surface area as assessed on computed tomography, as well as to clarify the impact of such changes on the clinical results. METHODS: Twenty-three shoulders of 21 subjects who underwent the modified Bankart and Bristow procedure were retrospectively analyzed. Computed tomography images were obtained immediately after surgery and at the final follow-up. The changes in bone surface area of the grafted coracoid process were measured on computed tomography slices in the proximity of the screw bore. Clinical outcomes were evaluated in terms of the Rowe, Walch-Duplay, and simple shoulder test scores. RESULTS: Bone area increased in 15 shoulders (65.2%) and decreased in eight shoulders (34.8%). Bone area increased by 51.3% in shoulders with bone union in the superior part of the coracoid process graft, with no significant differences between the superior and inferior sides of the graft regarding the rate of change in bone surface area (41.4% vs. 68.9% increase). However, in shoulders with bone union in the inferior part of the coracoid process graft, the rate of change in bone area differed significantly between the superior and inferior sides of the graft, exhibiting a 42.3% decrease on the superior side and 39.8% increase on the inferior side. In shoulders with no bone union, bone area decreased by 29.5% (17.4% vs. 39.3% decrease on the superior and inferior side, respectively), whereas the Rowe and Walch-Duplay scores were significantly lower than those noted in shoulders with bone union. CONCLUSIONS: Postoperative bone formation and bone resorption in the coracoid process grafted during the modified Bankart and Bristow procedure depend on whether and where bone union occurs. Graft non-union is associated with inferior clinical results.

Recovery of shoulder rotational muscle strength after a combined Bankart and modified Bristow procedure.

The objective of this study was to determine the influence of rotational muscle strength on shoulder function after a combined open Bankart and modified Bristow procedure and to determine the time of recovery for shoulder rotational strength. Fourteen patients were investigated by use of the relationship between the Rowe score and isokinetic concentric muscle strength. Forty patients were measured regarding the time course of muscle strength preoperatively and at 1.5, 3, 4.5, 6, 9, and 12 months postoperatively. There was a positive correlation coefficient between the Rowe score and muscle strength. The mean peak torque was significantly lower than the preoperative level at 1.5 and 3 months after surgery (P < .01) and recovered by 4.5 months after surgery. The contralateral peak torque ratio continued to increase until 12 months after surgery. These results indicate that high-level sports activities should be delayed until 9 to 12 months after a Bankart and modified Bristow procedure.

Labral shape after arthroscopic Bankart repair: comparisons between the anchor and Caspari methods.

PURPOSE: Morphological changes after repair of the glenoid labrum were examined using fresh cadavers and clinical cases to compare the anchor and Caspari methods. TYPE OF STUDY: Cadaveric and case series. METHODS: The depth of the glenoid concavity after Bankart repair was measured in 4 shoulders from 2 fresh cadavers. We made positive models of the glenoid cavity with gypsum and measured the distance from the lateral-most extent of the anterior labrum to the medial extent of the glenoid cavity. We also compared the depth of glenoid concavity in clinical cases between the anchor and Caspari methods using air computed tomography arthrography and magnetic resonance imaging. RESULTS: We determined the effective depth as the distance from the lateral-most extent of the anterior labrum to the medial extent of the glenoid cavity. The effective depth in fresh cadaver experiments after the anchor method showed substantial differences at the superior and middle levels of the glenoid labrum compared with the Caspari method. Mean effective depths in clinical cases were 5.8 mm (range, 4.2 to 6.8 mm) after the anchor method and 3.5 mm (range, 2.0 to 5.0 mm) after the Caspari method. Effective depth following the anchor method was significantly greater than that of the Caspari method. CONCLUSIONS: During repair of Bankart lesions for traumatic anterior instability of the shoulder, effective depth was higher following use of the anchor method than with the Caspari method. CLINICAL RELEVANCE: Understanding the shape of the anterior labrum and glenoid concavity after use of the anchor and Caspari methods may help to improve the surgical technique and clinical results of arthroscopic Bankart repair.

Tensile properties and biological response of poly(L-lactic acid) felt graft: an experimental trial for rotator-cuff reconstruction.

Poly(L-lactic acid) felt (PLLA felt) was prepared for reconstruction of the rotator cuff in animal models. Small changes were found in the tensile strength of both the cultured PLLA felt and the PLLA felt implanted on the paravertebral muscle of rabbits up to 16 postoperative weeks. The stiffness of the felt implanted on the muscle from 6 to 16 weeks showed a statistically significant increase. When the infraspinatus tendons of beagle dog were reconstructed with the PLLA felt, the ultimate strength of PLLA felt increased threefold, and the stiffness increased fivefold by 16 postoperative weeks compared to that of the initial PLLA felt. They were statistically significant (p < 0.01). All the implanted specimens ruptured at the junction between the bone and the PLLA felt. Histological examination demonstrated infiltration of fibrous tissue into the interstices of the PLLA felt fibers. Connection between the infraspinatus tendon and the PLLA felt was tight with the formed scar tissue, but the connective tissue between the bone and PLLA felt fibers was sparse even at 16 and 32 postoperative weeks. A few deteriorated PLLA felt fibers were observed at 32 postoperative weeks. It was concluded that the degradation rate of PLLA felt was low and the tensile recovery of the PLLA felt graft in beagle dogs was excellent. Thus, PLLA felt might be a useful bioabsorbable material for rotator-cuff reconstruction.

Snapping annular ligament of the elbow joint in the throwing arms of young brothers.

We examined young brothers with symptomatic snapping elbow in the throwing arm. Arthroscopic examination confirmed the mechanism of snapping, in which loose and protruded annular ligament-like tissue covered the volar half of the radial head in elbow extension and uncovered the radial head in deep elbow flexion. Arthroscopic resection of the annular ligament-like tissue was performed in one brother. Histologic examination of the removed tissue showed degenerated ligament tissue. Excision of loose annular ligament abolished snapping. Contralateral elbows of the brothers also showed similar asymptomatic snapping. Researchers suggest that a hereditary factor contributing to loose annular ligament and repetitive microtrauma from throwing is the cause of symptoms.

Effectiveness of external rotation immobilization in highly active young men with traumatic primary anterior shoulder dislocation or subluxation.

We treated 15 highly active young men (16 shoulders) with traumatic primary anterior shoulder dislocation or subluxation using 3-week external rotation immobilization. Fourteen patients (14 shoulders) were members of the Self-Defense Force and the other patient (2 shoulders) was a high school student who played club-level rugby. Average patient age at the time of the primary injury was 21.3 years (range, 17-26 years). Magnetic resonance imaging (MRI) was performed on 14 of 16 shoulders after the 3-week external rotation immobilization and showed that the anteroinferior labrum was reduced on the glenoid rim in 11 shoulders but remained medially displaced on the glenoid neck in 3 shoulders. Five shoulders, including these 3 shoulders, underwent arthroscopic Bankart repair after 3-week external rotation immobilization. Eleven shoulders continued nonoperative treatment after the immobilization. Four of 11 shoulders had no recurrence of symptoms for >2 years, and these patients were able to return to their preinjury activities. However, 7 shoulders experienced recurrence within 2 years. We concluded that external rotation immobilization may not be as effective as mentioned previously in highly active young men with primary traumatic anterior shoulder dislocation or subluxation. Whether a patient has instability symptom recurrence after external rotation immobilization depends on more than the fact that the anteroinferior labrum is not reduced on MRI.

Effects of light penetration and smear layer removal on adhesion of post-cores to root canal dentin by self-etching adhesives.

OBJECTIVES: This study investigated the effects of light penetration and removal of smear layer on the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts. METHODS: Altogether 54 human incisors and premolars were decoronated, and the roots after preparing the post space were randomly assigned into six groups. Three groups were treated with a light-cured self-etching adhesive and the other three with a dual-cured self-etching adhesive. In a further sub-division, the first group was light-cured with an irradiation unit; the second was light-cured with the irradiation unit and a light-guiding attachment; and the third was light-cured with the irradiation unit and the attachment after removing smear layer by EDTA and NaOCl. Then, a glass-fiber post was luted into the post space by a dual-cured composite. After 24h, an hourglass-shaped specimen was trimmed and subjected to MTBS testing. RESULTS: Using the light-guiding attachment and removing the smear layer reduced the incidence of pre-testing failure significantly from 57.1% to 19.0% (p<0.05) in the light-cured adhesive groups and from 68.3% to 3.2% (p<0.01) in the dual-cured adhesive groups. The MTBS in different locations within a post space were in the range from 8.9 to 17.5MPa in the light-cured group and from 11.2 to 17.2MPa in the dual-cured group. SIGNIFICANCE: Better light penetration in post spaces and removal of the smear layer are effective in improving the adhesive properties of self-etching adhesives to root canal dentin when using fiber posts.

The root canal bonding of chemical-cured total-etch resin cements.

Discovering a durable restorative method to reconstruct and reinforce pulpless teeth is a vital key to help prevent root fractures. Complete and firm adhesion of resin cement in root canal dentin using a post is critical to achieve it. The null hypothesis in the present study was that the bond strength of dual-cured and chemical-cured adhesive resin cements to root canal dentin is not affected by their vertical locations in the root canal. In the experiments, extracted human incisors restored with fiber-reinforced posts and adhesive resin cements were subjected to microtensile bond strength testing. Then, the failure modes and the dentin-bonding interfaces were observed. Self-etch and self-adhesive dual-cured resin cements showed frequent pretesting failure despite using a silane coupling agent. Chemical-cured total-etch adhesive material showed stable bonding performances throughout the entire post space and thus has an advantage in post-core restorations.

Lack of an association between 5-HT receptor gene polymorphisms and suicide victims.

An association between serotonergic dysfunction in the brain and suicidal behavior has previously been suggested. The high affinity of some antipsychotic and antidepressant drugs to serotonin 6 (5-HT6) receptors, and the predominant localization of 5-HT6 receptors in some limbic regions, suggest that 5-HT6 receptors play a role in the pathogenesis of suicide. The objective of the present study was to examine the association between suicide victims and two polymorphisms of the 5-HT6 receptor gene: a biallelic polymorphism (267C/T) in exon 1 and a trinucleotide repeat polymorphism ([GCC](2/3)) in the 5'-upstream region of the gene. The two polymorphisms were genotyped in 163 suicide victims and 166 controls, and the distribution of genotype and allele frequencies between the two groups were compared. Haplotype frequencies of these two polymorphisms were estimated from genotypic data by the maximum-likelihood method. In both polymorphisms, there were no significant differences in genotype or allele frequencies between the suicide victims and the controls. Moreover, there were no significant differences in the haplotype distributions of these polymorphisms between the two groups. These findings suggest that it is unlikely that the 5-HT6 receptor gene is involved in the susceptibility to suicide.

Association of 14-3-3 epsilon gene haplotype with completed suicide in Japanese.

Genetic factors have been suggested to be involved in suicide. Although some genetic factors, such as serotonergic transduction, have been associated with suicide, the results are inconsistent. There is a possibility that various signaling anomalies are involved in the biological vulnerability to suicide. We carried out a genome-wide gene-expression study in the brains of suicide victims using DNA microarrays;14-3-3 epsilon, which is related to neurogenesis, was one of the genes upregulated in the brains of suicide victims in the microarray analysis. This was confirmed by Western blot analysis. To examine the possibility of the involvement of 14-3-3 epsilon in the pathogenesis of suicide, we investigated the association of the 14-3-3 epsilon gene and completed suicide. We used three high-frequency SNPs (rs1532976, rs3752826, and rs9393) and found a significant association of two alleles (rs1532976 and rs3752826) with completed suicide (p < 0.05). Moreover, the distribution of haplotype revealed a more significant difference between completed suicide and controls (p=0.0005). This finding suggests that 14-3-3 epsilon is a potential suicide susceptibility gene and implies that dysregulation of neurogenesis may be involved in suicide.

Good clinical outcome of combined Bankart-Bristow procedure for recurrent shoulder instability: 126 patients followed for 2-6 years.

126 patients (100 men) with recurrent anterior shoulder dislocation or subluxation with severe Bankart lesion were treated with a combined Bankart and modified Bristow procedure and reviewed for this study. The mean age at operation was 25 (14-69) years, and mean follow-up period 41 (24-75) months. Averages of the Rowe score, the Constant score and the ASES score at final follow-up were 90, 95 and 91 points, respectively. The clinical outcome was excellent in 97 patients (77%), good in 16 (13%) and fair in 13 (10%). 2 patients had resubluxation, while no patient had a complete redislocation. The average loss of range of motion of external rotation, as compared to the contralateral shoulder side was 13 degrees. 67 of 72 patients returned to sports. No major postoperative complications occurred. This procedure had an excellent clinical outcome in cases of recurrent anterior shoulder dislocation or subluxation.

Augmentation with a Gore-Tex patch for repair of large rotator cuff tears that cannot be sutured.

The objective of this study was to determine the effectiveness of augmentation with a Gore-Tex patch in reconstruction of rotator cuff tears that cannot be repaired by direct suture. Twenty-eight shoulders of 27 patients underwent this procedure. The average age at surgery was 62 years, the average duration of symptoms before surgery was 16 months, and the average follow-up period was 44 months. The shoulders were classified into two groups according to patch size (anteroposterior dimension up to 2 cm or greater than 2 cm). The clinical outcome was evaluated by using the shoulder surgery classification system issued by the Japanese Orthopaedic Association (JOA score), and the postoperative isometric abduction strength at 90 degrees of abduction was assessed by the method of Constant. The average total JOA score improved from 57.7 to 88.7 points, a statistically significant change. There was no difference in the improvement in score between shoulders treated with small patches (12 shoulders) and those treated with large patches (16 shoulders). The average abduction strength was 6.2 kg in the small-patch group and 1.5 kg in the large-patch group, with a statistically significant difference between the two groups. Good clinical results, especially pain relief, could be achieved with this procedure in both the small- and the large-patch groups, but good abduction strength was obtained only in the small-patch group. The mechanism of the improvement by this procedure is still controversial.