Analysis of scapular kinematics during active and passive arm elevation

[Purpose] Early postoperative passive motion exercise after arthroscopic rotator cuff repair remains controversial. To better understand this issue, this study was aimed at evaluating scapular kinematics and muscle activities during passive arm elevation in healthy subjects. [Subjects and Methods] The dominant shoulders of 27 healthy subjects were examined. Electromagnetic sensors attached to the scapula, thorax, and humerus were used to determine three-dimensional scapular kinematics during active arm elevation with or without external loads and passive arm elevation. Simultaneously, the activities of seven shoulder muscles were recorded with surface and intramuscular fine-wire electrodes. [Results] Compared with active arm elevation, passive elevation between 30° and 100° significantly decreased the scapular upward rotation and increased the glenohumeral elevation angle. However, no significant differences in scapular posterior tilt and external rotation were observed between active and passive arm elevation, and scapular plane kinematics were not affected by muscle activity. [Conclusion] Unlike active motion with or without an external load, passive arm elevation significantly decreased the scapular upward rotation and significantly increased the mid-range glenohumeral elevation. These data, which suggest that passive arm elevation should be avoided during the early postoperative period, may expand the understanding of rehabilitation after arthroscopic rotator cuff repair.

Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model

OBJECTIVES

The objective of this study was to determine if the use of fascia lata as a tendon regeneration guide (placed into the tendon canal following harvesting the semitendinosus tendon) would improve the incidence of tissue regeneration and prevent fatty degeneration of the semitendinosus muscle.

MATERIALS AND METHODS

Bilateral semitendinosus tendons were harvested from rabbits using a tendon stripper. On the inducing graft (IG) side, the tendon canal and semitendinosus tibial attachment site were connected by the fascia lata, which was harvested at the same width as the semitendinosus tendon. On the control side, no special procedures were performed. Two groups of six rabbits were killed at post-operative weeks 4 and 8, respectively. In addition, three healthy rabbits were killed to obtain normal tissue. We evaluated the incidence of tendon tissue regeneration, cross-sectional area of the regenerated tendon tissue and proportion of fatty tissue in the semitendinosus muscle.

RESULTS

At post-operative week 8, the distal end of the regenerated tissue reached the vicinity of the tibial insertion on the control side in two of six specimens. On the IG side, the regenerated tissue maintained continuity with the tibial insertion in all specimens. The cross-sectional area of the IG side was significantly greater than that of the control side. The proportion of fatty tissue in the semitendinosus muscle on the IG side was comparable with that of the control side, but was significantly greater than that of the normal muscle.

CONCLUSIONS

Tendon tissue regenerated with the fascia lata graft was thicker than naturally occurring regenerated tissue. However, the proportion of fatty tissue in the semitendinosus muscle was greater than that of normal muscle.Cite this article: K. Tabuchi, T. Soejima, H. Murakami, K. Noguchi, N. Shiba, K. Nagata. Inducement of tissue regeneration of harvested hamstring tendons in a rabbit model. Bone Joint Res 2016;5:247-252. DOI: 10.1302/2046-3758.56.2000585.

Three-dimensional ultrastructural analysis of development at the supraspinatus insertion by using focused ion beam/scanning electron microscope tomography in rats

To obtain a successful outcome after rotator cuff repair, the repaired tendon must be biologically anchored to the bone. However, the histological structure at the repaired tendon-bone interface differs from that of the site of normal tendon insertion. Therefore, analyzing postnatal development in detail will contribute to understanding the repaired tendon-bone interface after rotator cuff repair. In this study, we analyzed postnatal development at the tendon-bone insertion in terms of temporal changes in SOX9/SCX expression and three-dimensional (3D) ultrastructure with FIB/SEM tomography, a new scanning electron microscopic method. Sixteen postnatal Sprague-Dawley rats were used for the study. One-, two-, three-, and four-week-old rats were sacrificed and both right and left shoulders were removed; eight normal supraspinatus tendon insertions were isolated for each time point. At each time point, four specimens were evaluated with fluorescent immunostaining for SOX9/SCX expression, and the remaining four specimens were evaluated with FIB/SEM tomography. Even in postnatal development, SOX9(+) /SCX(+) expression was observed at the tendon insertion; expression gradually decreased with postnatal development at the normal tendon insertion. In 3D ultrastructure, the morphology of the cells and the number/orientation of the cell processes drastically changed by postnatal week 4. The pattern of SOX9/SCX expression and 3D ultrastructural changes obtained in this study contribute to an understanding of the complicated development of normal tendon-bone insertion. Therefore, this study helps elucidate the pathophysiology of tendon-bone insertion, especially in cases of rotator cuff tear and repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:969-976, 2016.

GATA3 Expression Is a Poor Prognostic Factor in Soft Tissue Sarcomas

OBJECTIVE

Recent studies have investigated the significance of GATA3 expression in patients with various malignant tumors. However, no previous studies have evaluated the clinicopathological importance of GATA3 expression in soft tissue sarcomas (STS) patients.

METHODS

We evaluated GATA3 expression in 76 STS cases using immunohistochemical analysis, and statistically compared clinicopathological characteristics between GATA3-positive and GATA3-negative cases.

RESULT

GATA3-positive expression was significantly associated with a higher mitotic count (P < 0.0001). Disease-free survival (DFS) of GATA3-positive cases was significantly shorter than that of cases without GATA3 expression (P = 0.0104). Overall survival (OS) of GATA3-positive cases was significantly shorter than that of cases without GATA3 expression (P = 0.0006). GATA3-positive expression was significantly associated with shorter DFS in both univariate analysis (hazard ratio [HR], 2.719; P = 0.012) and multivariate analysis (HR, 2.711; P = 0.014). GATA3-positive expression was also significantly associated with worse OS in both univariate analysis (HR, 5.730; P = 0.0007) and multivariate analysis (HR, 5.789; P = 0.0008).

CONCLUSION

These results indicate that GATA3 is an independent prognostic factor and suggest that evaluation of GATA3 expression might enable more effective clinical follow-up using prognostic stratification of STS patients.

Anatomic Oblong Double Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle anterior cruciate ligament (ACL) reconstruction using hamstring tendon grafts is a standard procedure for ACL injury. However, its clinical effectiveness is not always satisfactory. One cause of this was problems with the graft-tunnel healing of the posterolateral bundle (PLB) on the femur. To solve this problem, we devised a new anatomic ACL reconstruction technique to improve the graft-tunnel healing of the femoral PLB by using a single-bundle with one bone tunnel on the femoral side and a double-bundle on the tibial side. We have performed 40 procedures with excellent results and no cases of intra- or postoperative complication. This procedure can help improve the graft-tunnel healing around the femoral bone tunnel aperture for the PLB.

A New Training for Older Adults Using Combined Neuromuscular Electrical Stimulation and Volitional Contraction: A Pilot Study

The hybrid training system (HTS) resists the motion of a volitionally contracting agonist muscle using force generated by its electrically stimulated antagonist. We have developed a new training method using the principle of HTS. This study was designed to evaluate the effect of HTS with electrical stimulation on muscle strength and physical function by comparing it against training without electrical stimulation in older adults. 16 subjects were randomly divided into two groups: the squat and single leg lift training (control, CTR) group, and the CTR with HTS training group. Some electrical stimulation was applied to the quadriceps and hamstring muscles in the HTS group. The subjects performed training for 25 min per session 3 times a week for 12 weeks. At points before and after the research maximal isokinetic torque, knee-flexors (KFT) and knee-extensors (KET), a one-leg standing test (OLT), a functional reach test (FRT), a 10-meter maximal gait time (10MGT) and Timed up & go test (TUG) were conducted. None of the subjects had any injuries during the study period. TUG significantly improved after the training period in both the HTS group (7.15 sec to 6.01 sec P = 0.01) and in the CTR.

Factors Affecting Clinical Outcome in Patients With Structural Failure After Arthroscopic Rotator Cuff Repair

PURPOSE

(1) To compare clinical outcomes between patients with large or massive rotator cuff tears who have healed cuffs and patients with postoperative structural failure (retear after complete or partial repair) and (2) to identify factors associated with clinical outcomes in patients with postoperative structural failure.

METHODS

We conducted a retrospective study of consecutive patients with large or massive cuff tears who underwent arthroscopic repair at our institution between 2005 and 2012. On the basis of intraoperative findings and magnetic resonance imaging at final follow-up, the patients were divided into 3 groups: healed group, retear group (after complete repair), and partial-repair group. The outcome measures comprised the Japanese Orthopaedic Association (JOA) and University of California, Los Angeles (UCLA) scores; muscle strength; and range of motion. The tear length, tear width, muscle atrophy, and fatty degeneration were evaluated by preoperative and postoperative magnetic resonance imaging. The extent of tendon reattachment to the superior, middle, and inferior facets and the lesser tuberosity was examined on magnetic resonance images at final follow-up.

RESULTS

In total, 74 patients (healed, 41; retear, 19; and partial repair, 14) were included in this study. The mean age was 63.8 ± 8.5 years, with a mean follow-up period of 3.6 ± 1.4 years. The postoperative JOA and UCLA scores significantly improved in all 3 groups, but the differences were not significant. In the retear and partial-repair groups, postoperative tendon preservation at the middle facet significantly affected the JOA and UCLA scores (P = .003 and P = .014, respectively).

CONCLUSIONS

The JOA and UCLA scores were significantly improved in patients with structural failure. Under these conditions, the only clinical factor that affected patient outcome was tendon healing at the middle facet. Thus tendon preservation at the middle facet was a predictor of good clinical outcomes in patients who underwent arthroscopic rotator cuff repair of large or massive tears and had postoperative structural failure.

LEVEL OF EVIDENCE

Level III, case-control study.

Infective Endocarditis Presenting as Right Shoulder Pain: A Case Report

Although cases of referred shoulder pain due to ischemic heart disease have been well documented, to our knowledge no reports on infective endocarditis accompanied by referred right shoulder pain have been published. A 43-year-old Japanese man presented with severe right shoulder pain and a body temperature of 38°C.Blood tests showed inflammation and liver dysfunction, although magnetic resonance imaging did not indicate septic shoulder arthritis. However, contrast-enhanced computed tomography showed renal, splenic, and hepatic infarctions. Moreover, a labile vegetation was detected on an echocardiogram. The patient was diagnosed with infective endocarditis and antibiotics were administered intravenously. Infective endocarditis is a serious condition that can result in complications if it is not diagnosed and treated at an early stage. Therefore, in cases with referred shoulder pain, physicians should carefully consider the presence of internal diseases that may cause this condition, as in the present case.

Effect of external load on scapular upward rotation during arm elevation: the knot concept

Background

Failure of the scapulohumeral rhythm (SHR) is observed in patients with shoulder joint dysfunction. The SHR reportedly has a 2:1 ratio during scapular upward rotation with arm elevation. However, three-dimensional scapular motion analysis has indicated variations in this ratio according to the arm elevation angle. We observed 2 distinct patterns: the scapular upward rotation decreased after knot formation (type I) or increased after knot formation (type II) during arm elevation. In the present study, we aimed to identify the knot and investigate the influence of varying external loads on this kinesiological change point.

Methods

We evaluated 35 healthy adult men (35 dominant-side shoulders) with a mean age of 20 ± 1.7 years (mean height: 172 ± 6.4 cm, mean weight: 65.7 ± 5.8 kg). Participants performed scapular plane elevation with no load or with an external load (1–5 kg) while sitting on a chair. The measured scapular upward rotation values were interpolated using the spline function and fitted to line graphs, and the change in these values was compared for various loads.

Results

The estimated knot angles (standard error) in the no load condition, and with external loads of 1, 2, 3, 4, and 5 kg were 83.5 (2.9°), 81.2 (2.9°), 81.0 (2.9°), 76.1 (2.9°), 73.4 (3.1°), and 75.8 (3.1°), respectively. No significant difference was noted in the knot position at 1–2 kg (vs. unloaded), although the knot was significantly lower at 3–5 kg (3 kg: p = 0.01, 4 kg: p = 0.001, and 5 kg: p = 0.02). Moreover, we observed that participants either exhibited increased or decreased upward rotational momentum after knot formation.

Conclusion

Our results confirm that the kinesiological change point (the knot) during scapular upward rotation occurred at lower angles in cases of increasing external loads.

Cycling Exercise with Electrical Stimulation of Antagonist Muscles Increases Plasma Growth Hormone and IL-6

Performing aerobics and resistance exercise at exactly the same time has not been available although combining both types of exercise in one training program has been attempted. The hybrid training system (HTS) is a resistance exercise that combines voluntary concentric muscle contractions with electrically stimulated eccentric muscle contractions. We devised an exercise technique using HTS on a cycle ergometer (HCE). Growth hormone (GH) and lactate are indicators of adequate training intensity. Interleukin-6 (IL-6) reflects enhancing lipid metabolism. The purpose of this study was to show that HCE provides sufficient exercise to stimulate the secretion of GH, lactate and IL-6. We compared an HCE test with cycle ergometer alone (CE). Ten healthy male subjects performed HCE and CE tests for 30 minutes each. The workload of both tests was set the same at 40% of each subject's peak oxygen uptake. For HCE, 2-minute HTS and 1-minute rest intervals were repeated. GH, lactate, and IL-6 were evaluated before and immediately after exercise, and at 15, 30 and 60 minutes. GH and lactate increased immediately after HCE. Moreover, the degree of the increases in GH after HCE (0 and 15 minutes) was higher than that after CE. IL-6 increased after HCE at 30 min, and the rate of change was higher than for CE. These results showed that HCE was more efficient in stimulating acute increases in GH, lactate and IL-6 than CE at the same workload. We may be able to combine electrically stimulated resistance exercise with aerobic exercise using HCE.

A Case of Acromioclavicular Joint Dislocation Associated with Coracoid Process Fracture

Rupture of any two or more parts of the superior shoulder suspensory complex (SSSC) including the distal clavicle, acromion, coracoid process, glenoid cavity of the scapula, acromioclavicular ligament, and coracoclavicular ligament is associated with shoulder girdle instability and is an indication for surgery. Here we report a case of acromioclavicular joint dislocation associated with coracoid process fracture. A 48-year-old man sustained a hard blow to the left shoulder from a fall, and simple radiography detected a coracoid process fracture and acromioclavicular joint dislocation. The injury consisted of a rupture of two parts of the SSSC. For the coracoid process fracture, osteosynthesis was performed using hollow cancellous bone screws. For the acromioclavicular joint dislocation, hook plate fixation and the modified Neviaser's procedure were performed. The bone healed well 5 months after surgery, at which time the screws were removed. At 18 months after initial surgery, the coracoid process fracture had healed with a 10% rate of dislocation on radiography, and the patient currently has no problem performing daily activities, no range of motion limitations, and a Japanese Orthopaedic Association scale score of 93.

Effects of corticosteroids and hyaluronic acid on torn rotator cuff tendons in vitro and in rats

Corticosteroids (CS) or hyaluronic acid (HA) is used in subacromial injection for the conservative treatment of rotator cuff tears (RCT); this study addresses the question of how CS and HA affect the tendon tissue and fibroblasts in vitro and in rats. Cell proliferation assays were performed in human tendon fibroblasts from RCT. Rats underwent surgery to create RCT, and the surgical sites were injected with CS or HA. The rotator cuff tendons were subjected to biomechanical testing, microscopic and immunohistochemical analysis of proliferating cell nuclear antigen (PCNA), and ultrastructural analysis. Cell proliferation was significantly decreased with CS in vitro (p < 0.05). Maximal load of CS-treated tendons was significantly decreased compared with that of HA-treated tendons (p < 0.05), as well as PCNA(+) cells at 2 weeks (p < 0.05). Ultrastructural observations of the CS-treated rats detected apoptosis of tendon fibroblasts 24 h after surgery. Histological and biomechanical data 4 weeks after surgery were not significant among the three groups. Unlike HA, CS caused cell death, and inhibition of the proliferation of tendon fibroblasts, leading to a delay of tendon healing involved and a subsequent decrease of biomechanical strength at the surgical site.

Electrically Stimulated Antagonist Muscle Contraction Increased Muscle Mass and Bone Mineral Density of One Astronaut - Initial Verification on the International Space Station

BACKGROUND

Musculoskeletal atrophy is one of the major problems of extended periods of exposure to weightlessness such as on the International Space Station (ISS). We developed the Hybrid Training System (HTS) to maintain an astronaut's musculoskeletal system using an electrically stimulated antagonist to resist the volitional contraction of the agonist instead of gravity. The present study assessed the system's orbital operation capability and utility, as well as its preventative effect on an astronaut's musculoskeletal atrophy.

METHODS

HTS was attached to the non-dominant arm of an astronaut staying on the ISS, and his dominant arm without HTS was established as the control (CTR). 10 sets of 10 reciprocal elbow curls were one training session, and 12 total sessions of training (3 times per week for 4 weeks) were performed. Pre and post flight ground based evaluations were performed by Biodex (muscle performance), MRI (muscle volume), and DXA (BMD, lean [muscle] mass, fat mass). Pre and post training inflight evaluations were performed by a hand held dynamometer (muscle force) and a measuring tape (upper arm circumference).

RESULTS

The experiment was completed on schedule, and HTS functioned well without problems. Isokinetic elbow extension torque (Nm) changed -19.4% in HTS, and -21.7% in CTR. Isokinetic elbow flexion torque changed -23.7% in HTS, and there was no change in CTR. Total Work (Joule) of elbow extension changed -8.3% in HTS, and +0.3% in CTR. For elbow flexion it changed -23.3% in HTS and -32.6% in CTR. Average Power (Watts) of elbow extension changed +22.1% in HTS and -8.0% in CTR. For elbow flexion it changed -6.5% in HTS and -4.8% in CTR. Triceps muscle volume according to MRI changed +11.7% and that of biceps was +2.1% using HTS, however -0.1% and -0.4% respectively for CTR. BMD changed +4.6% in the HTS arm and -1.2% for CTR. Lean (muscle) mass of the arm changed only +10.6% in HTS. Fat mass changed -12.6% in HTS and -6.4% in CTR.

CONCLUSIONS

These results showed the orbital operation capability and utility, and the preventive effect of HTS for an astronaut's musculoskeletal atrophy. The initial flight data together with the ground data obtained so far will be utilized in the future planning of human space exploration.

Effects of sex differences on scapular motion during arm elevation

INTRODUCTION

Scapular motion during arm elevation is frequently evaluated in patients with shoulder disorders because it provides clinically useful information. With the development of measurement devices and improvement in accuracy, comparisons under various conditions have recently been reported. However, in most of these reports, the subjects examined were limited to males, or a mixed population of males and females. Only a few reports have described sex differences. In the current study, we performed three-dimensional dynamic analysis of arm elevation and investigated whether there is a sex difference in scapular motion.

METHODS

Subjects included 18 healthy adult males (18 shoulders) and 19 healthy adult females (19 shoulders). Thirty-seven shoulders were on the dominant side. The age range was 20.5 ± 0.03 years. Subjects performed scapular plane arm elevation, and kinematic data were recorded using an electromagnetic tracking device. Scapular upward rotation and internal rotation angles and the posterior tilt angle accompanying arm elevation were calculated from recorded data. Changes in each angle during scapular motion were recorded according to sex.

RESULTS

There were sex differences in scapular upward rotation and internal rotation angles. The upward rotation angle was significantly greater in males, whereas the internal rotation angle was significantly greater in females. No sex differences were noted in the scapular posterior tilt angle.

DISCUSSION

Findings of this study may serve as basic data for scapular motion during scapular plane elevation in healthy males and females. In addition, it is necessary to evaluate and treat the shoulder while taking sex differences in scapular movement into consideration.

Effect of aging on volatile compounds in cooked beef

Volatiles in the headspace of beef cooked at 180 °C were analyzed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS), and the effects of aging were evaluated. Seventy volatile substances including non-aromatic, homocyclic, and heterocyclic compounds were identified. A significant positive regression model for storage could be adopted for toluene, benzeneacetaldehyde, 2-formylfuran, pyrazine, 2,6-dimethylpyrazine, 2,3-dimethylpyrazine, 2-acetylthiazole, and 2-formyl-3-methylthiophene. Increases in the quantity of these compounds, with the exception of toluene, suggest the importance of the Strecker and Maillard reactions in cooked meat previously aged under vacuum conditions. As such, the aging process may lead to an increase not only in the amount of compounds related to the taste of meat, but also in the quantity of odor-active compounds. The increased quantity of toluene during storage seemed to be influenced by lipid oxidation.

Anaplastic lymphoma kinase protein expression, genetic abnormalities, and phosphorylation in soft tissue tumors: Phosphorylation is associated with recurrent metastasis

Gene and protein abnormalities of anaplastic lymphoma kinase (ALK) play an important role in the pathogenesis of various cancers and serve as important therapeutic targets. We investigated ALK protein expression, phosphorylation, and genetic aberrations using fluorescence in situ hybridization (FISH) in 81 soft tissue tumor samples: inflammatory myofibroblastic tumor, n=1; alveolar soft part sarcoma, n=2; leiomyosarcoma, n=10; well-differentiated liposarcoma, n=7; pleomorphic liposarcoma, n=2; extraskeletal osteosarcoma, n=1; epithelioid sarcoma, n=1; synovial sarcoma, n=4; malignant peripheral nerve sheath tumor, n=4; undifferentiated pleomorphic sarcoma, n=19; rhabdomyosarcoma, n=6; myxofibrosarcoma, n=8; myxoid liposarcoma, n=11; fibrosarcoma, n=4; and desmoid-type fibromatosis, n=1. ALK protein expression, gene signal gain (without translocation), and phosphorylation were observed in 33/81 (40.7%), 55/81 (67.9%), and 30/81 (37.0%) tumor samples, respectively. ALK protein expression was statistically associated with phosphorylation, but not with gene signal gain. ALK phosphorylation-positive cases showed a statistically worse metastasis-free survival compared with phosphorylation-negative cases (P=0.0215). Particularly, metastasis of myxoid liposarcoma was associated with ALK phosphorylation (P=0.0019), but not with ALK protein expression or gene signal gain. However, the prognosis had no association with ALK protein expression, gene signal gain, or phosphorylation. ALK protein expression and phosphorylation play an important role in tumor biology and provide potential therapeutic targets for soft tissue tumors. Future research should focus on the oncogenic role and the efficacy of potential inhibitors of ALK.

Electromyographic study of rotator cuff muscle activity during full and empty can tests

The empty can (EC) and full can (FC) tests are used as diagnostic tools for patients with rotator cuff disease. However, recently concerns have been raised that these tests do not selectively activate the muscle. Therefore, the purpose of this study was to evaluate the rotator cuff muscle activation levels during the EC and FC tests in various positions using electromyography. Twelve healthy, right-handed men without shoulder complaints (mean age: 26.1 years, range: 23-35 years) were included. The tests were performed isometrically with the shoulder elevated at 45° and 90° in the sagittal, scapular, and coronal planes, either in the thumb-up (FC test) or thumb-down (EC test) positions. During these positions, the electromyographic signal was recorded simultaneously from the four shoulder muscles using a combination of surface and intramuscular fine-wire electrodes. The average activation of the supraspinatus and subscapularis was greater during the EC test than during the FC test and in the scapular and coronal planes than in the sagittal plane at 90°. For the infraspinatus, there were no significant differences in any positions between the two tests. Thus, the rotator cuff muscles are influenced by arm position and the elevation plane during the EC and FC tests.

A unique case of segmental vasal atresia

We report a case of a 2-year-old boy who presented with an empty left scrotum. Clinical examination revealed a left palpable undescended testis. During orchidopexy, segmental atresia of the vas deferens was found, and microsurgical repair was carried out. Segmental vasal atresia is an extremely rare condition and is infrequently diagnosed, especially in the pediatric age group. This is the first reported case of segmental vasal atresia without an association with cystic fibrosis.

Clinical outcomes of the Cadenat procedure in the treatment of acromioclavicular joint dislocations

We report our clinical experience using the modified Cadenat method to treat acromioclavicular joint dislocation, and discuss the usefulness of this method. This study examined 6 shoulders in 6 patients (5 males, 1 female) who were diagnosed with acromioclavicular joint dislocation and treated with the modified Cadenat method at our hospital. Average age at onset was 49.3 years (26-78 years), average time interval from injury until surgery was 263.8 days (10 to 1100 days), and the average follow-up period was 21.7 months (12 to 42 months). Post-operative assessment was performed using plain radiographs to determine shoulder joint dislocation rate and Japanese Orthopaedic Association (JOA) score. The average post-operative JOA score was 94.1 points (91 to 100 points). The acromioclavicular joint dislocation rate improved from 148.7% (72 to 236%) before surgery to 28.6% (0 to 60%) after surgery. Conservative treatment has been reported to achieve good outcomes in acromioclavicular joint dislocations. However, many patients also experience chronic pain or a sensation of fatigue upon putting the extremity in an elevated posture, and therefore ensuring the stability of the acromioclavicular joint is crucial for highly active patients. In this study, we treated acromioclavicular joint dislocations by the modified Cadenat method, and were able to achieve favorable outcomes.