Arthroscopic tenodesis using a bioabsorbable interference screw and soft anchor: A case series of 60 patients.

BACKGROUND: Various arthroscopic tenodesis techniques for the treatment of long head of the biceps tendon pathologic abnormalities have been described. PURPOSE: This study evaluated the clinical outcomes of using a bioabsorbable interference screw and soft anchor for long head of the biceps tendon arthroscopic tenodesis. METHODS: Sixty patients treated by this technique between February 2013 and March 2015 were followed up for at least 2 years. In our operative technique, after the bone hole was made just proximal to the pectoralis major, the soft anchor was inserted at the bottom of the hole. After tenotomy of the long head of the biceps tendon proximal to the bone hole, the tendon was fixed into the bottom of the hole temporarily using the soft anchor. Finally, the tendon was fixed in the hole with a bioabsorbable interference screw. RESULTS: The UCLA score 15.1 points preoperatively and 32.4 points at follow-up (p < 0.05). The Constant 55.8 points preoperatively and 93.9 points at follow-up (p < 0.01). After biceps tenodesis, no cosmetic deformities were found in 56 patients (93.3%), and four patients (6.7%) had a Popeye deformity. On postoperative magnetic resonance evaluation, the long head of the biceps tendon was located on the bicipital groove without deviation in 53 cases (88.3%), on the bicipital groove with a partial deviation in 6 cases (10.0%), and outside the bicipital groove with complete deviation (dislocated) in 1 case (1.7%). CONCLUSION: We found that arthroscopic biceps tenodesis using a soft anchor provided a reliable means for treating biceps pathology with no cosmetic deformities and with good clinical results.

Influence of a nerve injury proximal to the suprascapular nerve on healing of repaired rotator cuff tear.

BACKGROUND: Massive rotator cuff tears have a high rate of re-injury because of severe fatty infiltration. Our data showed that injuries proximal to the suprascapular nerve may be one cause of massive rotator cuff tears. The purpose of this study was to evaluate, using a rat model, how brachial plexus injury associated with a massive rotator cuff tear influences healing of the rotator cuff repair. METHODS: Seventy Sprague-Dawley rats were divided into three groups: rotator cuff tear with BP injury (DT group) (n = 28), rotator cuff tear without brachial plexus injury (T group) (n = 28), and a sham-operated group (n = 14). In the DT group, the rotator cuff tear was made and repaired 4 weeks after brachial plexus ligation. The gross assessment (evaluated the wet weight), biomechanical testing (evaluated the yield stress and the Young's modulus) and histological analyses (using the Bonar scale) were performed at baseline in the sham group, and at 4 and 12 weeks postoperatively in the DT and T groups (n = 7/group/time). RESULTS: Mean wet weight and yield stress were significantly lower in the DT group than in the T group. Additionally, the mean Young's modulus was significantly higher in the DT group than in the T group. Histologically, greater tendon degeneration was observed around the musculotendinous junction in the DT group than in the T group. CONCLUSION: The gross, biomechanical and histological data show that the repaired rotator cuff tendon with brachial plexus injury in rats does not heal as well as a repaired tendon without an accompanying brachial plexus injury. This suggests that more proximal neuropathy is one risk factor for re-tear of a repaired rotator cuff tendon.

Relationship between neuropathy proximal to the suprascapular nerve and rotator cuff tear in a rodent model.

BACKGROUND: Rotator cuff tears are believed to coexist with cervical spine lesions. In cases of preexisting neuropathy, such as cervical spine lesions, fatty degeneration has likely already occurred due to the neuropathy. In these cases, rotator cuff tear is thought to occur easily because of preexisting extensive fatty degeneration and degeneration of the tendons due to neuropathy. This study aimed to evaluate the effects of paralysis due to neuropathy proximal to the suprascapular nerve on the supraspinatus and infraspinatus tendons using a rat model of brachial plexus paralysis. METHODS: This study included fifteen, 8-week-old Sprague-Dawley rats. The left shoulder was included in the paralysis group and the contralateral shoulder constituted the sham group. Biomechanical testing (evaluated maximum tear force, maximum displacement and Young's modulus) (n = 10) and histological analyses (n = 5) (using the Bonar scale) were performed at 12 weeks postoperatively to confirm the degeneration of the tendon. RESULTS: The mean maximum tear force was significantly lower in the paralysis group than in the sham group (P = 0.008), indicating that rotator cuff tears occurred with a lower force in the paralysis group. Additionally, the average Young's modulus was significantly greater in the paralysis group than in the sham group (P = 0.003), indicating that the rotator cuff muscle became hard and inflexible in the paralysis group. The Bonar scales of the histological analyses were significantly higher in the paralysis group (total score = 7.04 ± 0.61) than the sham group (total score = 0) (p < 0.0001). CONCLUSIONS: If neuropathy of proximal to the suprascapular nerve, such as cervical spine or brachial plexus lesion, exists, weakness and degeneration of the rotator cuff tendon and stiffness of the rotator cuff muscle develop. Neuropathy is likely a cause of rotator cuff tears.

Histological analysis and biomechanical evaluation of fatty infiltration after rotator cuff tear and suprascapular nerve injury in a rat model.

BACKGROUND: Rotator cuff tears are the most common shoulder injury, and little is known about the underlying etiology of fatty infiltration after rotator cuff tear. Previous studies speculated that rotator cuff tears lead to neural injury due to tethering of the suprascapular nerve at the notch. This study aimed to evaluate fatty infiltration after suprascapular nerve injury and rotator cuff tears. METHODS: Ninety adult male Sprague-Dawley rats were used and were divided into four groups: sham, tendon transection only, suprascapular nerve ligation, and tendon transection plus suprascapular nerve ligation. The suprascapular nerve injury models were created by tying the suprascapular nerve. At 2, 4, and 8 weeks postoperatively, histological analysis and biomechanical testing were performed to evaluate fatty infiltration and elastic change in the supraspinatus muscles. RESULTS: The amount of fatty infiltration in the supraspinatus muscle was significantly higher in both the suprascapular nerve ligation and tendon transection plus suprascapular nerve ligation groups than in the tendon transection only group at 2, 4, and 8 weeks. The ultimate failure load and tensile strength were significantly different among the tendon transection only, suprascapular nerve ligation, and tendon transection plus suprascapular nerve ligation groups at 8 weeks postoperatively. Furthermore, the mean Young's modulus of the muscle was significantly greater in the tendon transection plus suprascapular nerve ligation group than in both the tendon transection only and suprascapular nerve ligation groups at 8 weeks postoperatively. CONCLUSIONS: In this study, based on the results of histological and biomechanical examinations in our rat models, the etiology of fatty infiltration after massive rotator cuff tear might be different from the suprascapular nerve injury.

Macroscopic and histologic evaluation of a rat model of chronic rotator cuff tear.

BACKGROUND: The major cause of rotator cuff tears in humans is thought to be tendon degeneration. Although some studies have reported chronic rotator cuff tear models in animals, few studies of chronic rat models have demonstrated persistent defects for a relatively long time. The purpose of this study was to establish a chronic rotator cuff tear model in the rat and to evaluate the model macroscopically and histologically. METHODS: Sixty Sprague Dawley rats were divided into 2 groups: tendon detachment only (tear group) and tendon detachment plus figure resin (chronic group). The contralateral shoulder served as a sham-operated control (sham group). In the tear group, the supraspinatus and infraspinatus tendons were completely detached. In addition to cuff detachment, figure resin was placed on the greater tuberosity to prevent cuff reattachment and scar formation in the chronic group. Macroscopic and histologic changes were assessed at 4 and 12 weeks after surgery. RESULTS: A full-thickness cuff defect was observed in all chronic-group rats at both 4 and 12 weeks after surgery, and it could be repaired secondarily by traction in lower tension. However, no cuff defects were observed in the tear group because of obvious scar tissue formation. On histologic evaluation, progressive tendon degeneration, muscle atrophy, and fatty infiltration were observed in the chronic model at 12 weeks after surgery. CONCLUSION: We established a rat model of chronic rotator cuff tears using figure resin. This chronic rotator cuff tear model might be useful for further clinical investigations of rotator cuff repair.

In vivo 3-dimensional analysis of scapular and glenohumeral kinematics: comparison of symptomatic or asymptomatic shoulders with rotator cuff tears and healthy shoulders.

BACKGROUND: Alteration in shoulder kinematics has been suggested as one cause of symptoms in shoulders with rotator cuff tears (RCTs). However, only a few studies comparing symptomatic and asymptomatic RCTs using kinematic analysis have been performed. The purpose of this study was to compare 3-dimensional (3D) scapular and glenohumeral kinematics during scapular-plane abduction among symptomatic RCTs, asymptomatic RCTs, and healthy shoulders. METHODS: This study included 7 healthy shoulders in subjects with a mean age of 62 years, 5 symptomatic RCTs in subjects with a mean age of 70 years, and 7 asymptomatic RCTs in subjects with a mean age of 67 years. All shoulders with RCTs had medium-sized tears (1-3 cm in the coronal plane) that were confirmed with magnetic resonance imaging. Biplane fluoroscopic images during scapular-plane abduction were recorded, and computed tomography-derived 3D bone models were matched with the silhouettes of the bones on the fluoroscopic images using 3D/2-dimensional model-image registration techniques. Angular values of the scapula and glenohumeral kinematics were compared among the 3 groups. RESULTS: Posterior tilt of the scapula was significantly smaller in the symptomatic RCTs (3.1° ± 1.8°) than in healthy shoulders (10.4° ± 0.8°) (P = .049). The humerus of the symptomatic shoulders was less externally rotated relative to the scapula throughout the activity than the healthy shoulders and asymptomatic RCTs (P = .006 and P = .028 respectively). However, there were no kinematic differences between the asymptomatic RCTs and healthy shoulders. CONCLUSION: Kinematic changes in symptomatic RCTs might be associated with development of symptoms. Improvement of these kinematic changes may be a key to successful conservative treatment for symptomatic RCTs.

Multiple Epiphyseal Dysplasia With Knee Joint Locking Symptoms Caused by Intra-articular Loose Bodies.

Multiple epiphyseal dysplasia (MED) is a congenital disease causing epiphyseal dysplasia in long bones. Herein, we report a case of a middle-aged man with bilateral knee joint locking symptoms who was diagnosed with multiple epiphyseal dysplasia caused by Matrilin-3 (MATN3) pathogenic variants and was successfully treated with arthroscopic loose body removal. A 48-year-old man has had bilateral knee pain since his twenties and underwent loose body removal of both knees in his thirties. He visited our hospital for worsening locking symptoms in both knees. Twenty years ago, his son had been diagnosed with suspected multiple epiphyseal dysplasia. Genetic and imaging testing confirmed his diagnosis of multiple epiphyseal dysplasia due to Matrilin-3 pathogenic variants. Arthroscopic loose body removal was performed, and the locking symptoms disappeared after surgery. Arthroscopic loose body removal was effective for the locking symptoms in a mild adult case of multiple epiphyseal dysplasias caused by Matrilin-3 pathogenic variants.

Efficacy of hyaluronic acid or steroid injections for the treatment of a rat model of rotator cuff injury.

This study evaluated dorsal root ganglia from C3-C7, analyzed gait, and compared the expression of calcitonin gene-related peptide (CGRP) which was a marker of inflammatory pain in a rat rotator cuff tear model in which the supraspinatus and infraspinatus tendons were detached; comparisons were made to a sham group in which only the tendons were exposed. Fluorogold was injected into the glenohumeral joint 21 days after surgery in both groups, and saline, steroids, or hyaluronic acid was injected into the glenohumeral joint in the rotator cuff tear group 26 days after surgery. The proportions of CGRP-immunoreactive neurons were higher and the gait parameters were impaired in the rotator cuff tear group compared to in the sham group. However, the CGRP expression was reduced and the gait was improved with steroid or hyaluronic acid injection compared to saline, suggesting that both hyaluronic acid and steroid injections suppressed of inflammation which thought to be provided pain relief. While there were no significant differences, the suppression of CGRP expression and the improved gait after hyaluronic acid and steroid injections suggested that both methods were effective for rat rotator cuff tear model.

Relationship Between Tightness of the Hip Joint and Elbow Pain in Adolescent Baseball Players.

BACKGROUND: Repetitive tensile stresses from valgus torque can induce elbow injury in adolescent baseball players. Insufficient hip range of motion (ROM) can change throwing mechanics, reducing the transfer of energy from the lower to the upper extremities. Thus, hip ROM limitations may force the upper extremities to bear the burden of a strong throw. Improper pitching mechanics caused by insufficient hip ROM are thought to increase valgus torque on the elbow when throwing, increasing the risk of elbow injury. PURPOSE: To investigate the relationship between elbow pain and hip ROM in adolescent baseball players. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: A total of 122 adolescent baseball players with a mean age of 12.0 years (range, 6-14 years) participated in this study. Elbow pain, hip flexion angle, and the internal rotation angles of the hip at 0° and 90° of flexion were assessed. Participants were divided into a pain group and a normal group based on the pain assessment, and each hip angle was compared between groups using Student t tests. P values <.05 were considered statistically significant. RESULTS: Thirty-one of 122 players had elbow pain. The hip flexion angle of the trail leg was 121.9° ± 12.3° for the normal group and 111.2° ± 11.3° for the pain group (P = .0001). The plant leg hip flexion angles were 122.0° ± 12.4° and 113.6° ± 11.3° (P = .0014) for the normal and pain groups, respectively. The internal rotation angle at 0° of hip flexion of the trail leg was 49.4° ± 12.6° and 45.6° ± 8.8° (not significant), and of the plant leg was 49.1° ± 12.5° and 48.7° ± 11.5° (not significant), for the normal and pain groups, respectively. The internal rotation of the trail leg at 90° of hip flexion was 46.9° ± 13.3° in the normal group and 36.1° ± 15.7° in the pain group (P = .0005). In the plant leg, the internal rotation angle at 90° of hip flexion was 46.9° ± 12.2° and 36.4° ± 18.1° for the normal and pain groups, respectively (P = .0013). CONCLUSION: Limitations to hip flexion and internal rotation at 90° of hip flexion were risk factors for elbow injury. Differences in internal rotation angles between 0° and 90° of hip flexion may be important criteria for identifying adolescent baseball players at risk of elbow pain.

Assessment of pain-related behavior and pro-inflammatory cytokine levels in the rat rotator cuff tear model.

The cause of pain following rotator cuff tear has not been fully elucidated. The purpose of this study was to evaluate behavior and inflammatory cytokines in a rat unstabilized rotator cuff defect (UCD) model. Forty-five Sprague-Dawley rats were divided into three groups: sham; UCD; and stabilized rotator cuff defect (SCD). Gait analysis was examined using CatWalk. Tumor necrosis factor (TNF)-α, interleukin(IL)-1ß, and IL-6 were measured within the subacromial bursa and the glenohumeral joint synovium at 21 and 56 days after surgery using an enzyme-linked immunosorbent assay (ELISA). Stride length, print area and contact intensity in the UCD group was significantly lower than in the sham group after surgery. Stride length, print area and contact intensity in the SCD group was significantly higher than in the UCD group. In contrast, TNF-α, IL-1ß, and IL-6 in the UCD group was significantly higher than in the sham group at days 21 and 56. However, TNF-α, IL-1ß, and IL-6 in the SCD group was significantly lower than in the UCD group at days 21 and 56. The present results suggest that SCD is effective not only in improving shoulder function but also in reducing inflammatory cytokines, which may serve as one source of pain due to rotator cuff tear.