Validation and reliability of a Japanese version of the Shoulder Pain and Disability Index: A cross-sectional study.

BACKGROUND: The Shoulder Pain and Disability Index (SPADI) is a simple disease specific questionnaire that is used to evaluate the impact of shoulder disorders. The purpose of this study was to translate the SPADI into Japanese (SPADI-Jp) and evaluate its reliability and validity in Japanese patients with shoulder disorders. METHODS: Cross-cultural adaptation of the SPADI was performed according to international guidelines. A total of 100 patients with shoulder disorders participated in this study. Each participant was asked to finish the SPADI-Jp, Disability of Arm, Shoulder and Hand (DASH), and the Short-Form 36 (SF-36) at the initial visit. Thirty-four patients repeated the SPADI-Jp to assess the test-retest reliability. The test-retest reliability was quantified using the interclass correlation coefficient (ICC), while Cronbach's alpha was calculated to assess the internal consistency. The construct validity was assessed using Spearman's rank correlation coefficients. RESULTS: Internal consistency in the SPADI-Jp was very high (0.969), as measured by the Cronbach's alpha. The ICC of the SPADI-Jp was 0.930. There was a strong, positive correlation between the DASH and the SPADI-Jp (r = 0.837, p < 0.001). The SPADI-Jp was significantly correlated with most of the SF-36 subscales. The correlations of the SPADI-Jp with physical subscales of the SF-36 were stronger than those with the other subscales. CONCLUSIONS: We demonstrated that the SPADI-Jp is a reliable and valid self-assessment tool. Because cross-cultural adaptation, validation, and reliability of the disease-specific questionnaire for shoulder pain and disability have not been evaluated in Japan, the SPADI-Jp can be useful for evaluating such patients in the Japanese population.

Joint hemorrhage accelerates cartilage degeneration in a rat immobilized knee model.

BACKGROUND: Joint hemorrhage is caused by trauma, ligament reconstruction surgery, and bleeding disorders such as hemophilia. Recurrence of hemorrhage in the joint space induces hemosiderotic synovitis and oxidative stress, resulting in both articular cartilage degeneration and arthropathy. Joint immobilization is a common treatment option for articular fractures accompanied by joint hemorrhage. Although joint hemorrhage has negative effects on the articular cartilage, there is no consensus on whether a reduction in joint hemorrhage would effectively prevent articular cartilage degeneration. The purpose of this study was to investigate the effect of joint hemorrhage combined with joint immobilization on articular cartilage degeneration in a rat immobilized knee model. METHODS: The knee joints of adult male rats were immobilized at the flexion using an internal fixator from 3 days to 8 weeks. The rats were randomly divided into the following groups: immobilized blood injection (Im-B) and immobilized-normal saline injection (Im-NS) groups. The cartilage was evaluated in two areas (contact and non-contact areas). The cartilage was used to assess chondrocyte count, Modified Mankin score, and cartilage thickness. The total RNA was extracted from the cartilage in both areas, and the expression of metalloproteinase (MMP)-8, MMP-13, interleukin (IL)-1ß, and tumor necrosis factor (TNF)-α was measured by quantitative real-time polymerase chain reaction. RESULTS: The number of chondrocytes in the Im-B group significantly decreased in both areas, compared with that in the Im-NS group. Modified Mankin score from 4 to 8 weeks of the Im-B group was significantly higher than that of the Im-NS group only in the contact area. The expression of MMP-8 and MMP-13 from 2 to 4 weeks and TNF-α from 2 to 8 weeks significantly increased in the Im-B group compared with those in the Im-NS group, but there was no significant difference in IL-1ß expression. CONCLUSIONS: The results showed that joint hemorrhage exacerbated immobilization-induced articular cartilage degeneration. Drainage of a joint hemorrhage or avoidance of loading may help prevent cartilage degeneration during joint immobilization with a hemorrhage.

Effects of joint capsular release on range of motion in patients with frozen shoulder.

BACKGROUND: A thickened joint capsule is believed to be one of the most specific manifestations of and the primary restraint against range of motion (ROM) in frozen shoulders. The purpose of this study was to evaluate the relationship among ROMs under general anesthesia before surgery and the effects of each joint capsular release on ROM. METHODS: ROM was measured using a goniometer with scapular fixation. Arthroscopic pan-capsular release was performed with the patient in the beach-chair position in the following order: (1) rotator interval, (2) coracohumeral ligament, (3) superior capsule, (4) middle glenohumeral ligament, (5) anterior inferior glenohumeral ligament, and (6) posterior inferior glenohumeral ligament. ROMs in forward flexion (FF), lateral elevation (LE), external rotation with the arm at the side (ER1), external rotation at 90° of LE (ER2), internal rotation at 90° of LE (IR2), horizontal flexion, external rotation at 90° of FF (ER3), and internal rotation at 90° of FF (IR3) were evaluated before and after each release. RESULTS: A total of 32 consecutive shoulders were included. After each capsular release, the ROM recovered; the final ROM was significantly greater on the affected side than on the unaffected side. Significant correlations were found between FF and LE, FF and ER1, ER1 and ER2, ER1 and ER3, ER2 and ER3, and IR2 and IR3 on both sides, regardless of surgery. CONCLUSION: Each segment of the joint capsule affected ROM in all directions, supporting the need for whole-joint capsular release; ROM was significantly greater on the affected side than on the unaffected side after surgery.

Restriction in the hip internal rotation of the stride leg is associated with elbow and shoulder pain in elite young baseball players.

BACKGROUND: Evidence is scarce concerning the relationship of physical dysfunction of the trunk and lower extremities with elbow and shoulder pain in young baseball players. This study aimed to examine the association of joint flexibility of the trunk and lower extremities and dynamic postural control with elbow and shoulder pain among elite young baseball players. METHODS: We analyzed baseball players (aged 9-12 years) who participated in the National Junior Sports Clubs Baseball Festival. Range of motion in external rotation and internal rotation (IR) of the hip, as well as the finger-to-floor distance and heel-to-buttock distance, was measured. The straight-leg-raise test was also conducted. Dynamic postural control was evaluated using the Star Excursion Balance Test. Multivariable logistic regression analyses were conducted to examine the association of physical function with the elbow or shoulder pain incidence. RESULTS: Of 210 players surveyed, 177 without elbow or shoulder pain were included in the analysis. Of the participants, 16 (9.0%) reported having elbow or shoulder pain during the tournament. Participants with the incidence of elbow or shoulder pain had a significant restriction in hip IR of the stride leg compared with those without pain (35.8° vs. 43.7°, P = .022). There were no significant associations of other joint flexibilities and the Star Excursion Balance Test with elbow or shoulder pain. CONCLUSION: Decreased hip IR range of motion of the stride leg was significantly associated with the elbow or shoulder pain incidence. Players, coaches, and clinicians should consider the physical function of the trunk and lower extremities for the prevention of elbow and shoulder pain.

RAGE-dependent NF-kB inflammation processes in the capsule of frozen shoulders.

BACKGROUND: The etiology of frozen shoulder (FS) remains uncertain. Advanced glycation end-products (AGEs) cause the cross-linking and stabilization of collagen and are increased in FS. The purpose of this study was to elucidate the pathogenesis of FS by evaluating the receptor of AGE (RAGE)-dependent pathways. METHODS: Tissue samples of the coracohumeral ligament (CHL) and anterior inferior glenohumeral ligament (IGHL) were collected from 33 patients with FS, with severe stiffness, and 25 with rotator cuff tears (RCTs) as controls. Gene expression levels of RAGE, high-mobility group box 1 (HMGB1), Toll-like receptor 2 (TLR2), TLR4, nuclear factor-kappa B (NF-kB), and cytokines were evaluated using a quantitative real-time polymerase chain reaction. The immunoreactivities of carboxymethyllysine (CML), pentosidine, and RAGE were also evaluated. CML and pentosidine were further evaluated using high-performance liquid chromatography. RESULTS: Gene expression levels of RAGE, HMGB1, TLR2, TLR4, and NF-kB were significantly greater in the CHLs and IGHLs from the FS group than in those from the RCT group. Immunoreactivities of RAGE and CML were stronger in the CHLs and IGHLs from the FS group than in those from the RCT group. Pentosidine was weakly immunostained in the CHLs and IGHLs from the FS group. CML using high-performance liquid chromatography was significantly greater in the CHLs and IGHLs from the FS group than in those from the RCT group. CONCLUSIONS: AGEs and HMGB1 might play important roles in the pathogenesis of FS by binding to RAGE and activating NF-kB signaling pathways. Suppression of these pathways could be a treatment option for FS.

Correlations Between Range of Motion and Elasticity of the Coracohumeral Ligament Evaluated With Shear-Wave Elastography.

CONTEXT: Range of motion (ROM) in the glenohumeral joint decreases with age in healthy subjects; however, the underlying mechanism remains unclear. The process of aging of the joint capsule, including the coracohumeral ligament (CHL), could affect ROM limitation. OBJECTIVE: This study investigated correlations between elasticity of the CHL, evaluated by means of shear-wave elastography, and age, side dominance, and ROM in healthy individuals. DESIGN: Experimental study. SETTING: Laboratory. SUBJECTS: Eighty-four healthy volunteers (39 men and 45 women, mean age: 42.6 y) were included. MAIN OUTCOME MEASURES: Subjects were divided into 3 age groups: younger (20-39 y), middle (40-59 y), and older (≥60 y) age groups. With participants in the supine position, CHL elasticity in both shoulders was evaluated in both neutral and 30° external rotation, with arms at the sides. ROM, including forward flexion, lateral elevation, external rotation, 90° abduction with external rotation, and hand behind the back were measured with participants in the standing position. RESULTS: The CHL elastic modulus was higher in the older group than in the younger group in the neutral (78.4 kPa [SD: 37.1] and 56.6 kPa [SD: 31.7], respectively) and 30° external rotation positions (135.5 kPa [SD: 63.5] and 71.4 kPa [SD: 32.2], respectively). Negative correlations were found between the CHL elastic modulus and ROM in terms of 30° external rotation and both external rotation (R = -.59, P = .02) and 90° abduction with external rotation (R = -.71, P = .003) in the older group, with correlation coefficients increasing with age. CONCLUSIONS: Significant correlations were identified between CHL elasticity and ROM in both external rotation and 90° abduction with external rotation with increasing age. Decreased CHL elasticity was strongly associated with decreased shoulder ROM in middle-aged and older individuals.

Incidence of four major types of osteoporotic fragility fractures among elderly individuals in Sado, Japan, in 2015.

The aim of this study was to survey the incidence of osteoporotic fragility fractures, which include vertebral, hip, distal radius, and proximal humerus fractures, in patients ≥ 50 years of age, from 2004 to 2015, in Sado City, Japan. We examined temporal changes in the incidence of these fractures from 2010 through 2015. The incidence of vertebral (p < 0.001) and radius fractures (p = 0.001) was lower in 2015 than in 2010, with only the incidence of hip fracture (p = 0.013) being lower in 2015 than in 2004. With regard to age-specific incidences, there was a sharp increase in vertebral and hip fractures among the segment of the population 70-89 years old, with no remarkable change in the incidence of radial and humeral fractures. Pre-existing vertebral fractures were identified in 69.6% of patients with a hip fracture, 35.6% of patients with a distal radius fracture, and 55% of patients with a humeral fracture. Among patients with pre-existing vertebral fractures, 42.5% had a single fracture, whereas 57.5% had 2 or more fractures. The proportion of patients on anti-osteoporotic agents before the occurrence of fractures increased to 14.5% in 2015, compared to 4% in 2004 and 7.6% in 2010. We speculate that the increase in the use of anti-osteoporotic agents is the main reason for the declining incidence of fractures. Therefore, considering the sharp increase in hip and vertebral fractures among individuals in their mid-1970s and older, judicious use of anti-osteoporotic agents among these individuals could be useful for lowering the occurrence of these fractures.

Playing video games for more than 3 hours a day is associated with shoulder and elbow pain in elite young male baseball players.

BACKGROUND: The effect of lifestyle factors on elbow or shoulder pain in young baseball players remains unclear. This study examined the association of game playing and television viewing with elbow or shoulder pain among elite young baseball players. METHODS: Study participants were young baseball players (age, 9-12 years) who participated in the National Junior Sports Clubs Baseball Festival in 2017. The national tournament invited 16 teams (totaling 210 players) selected based on the results of the regional qualifying tournaments. Self-reported questionnaires were mailed to all players before the tournament. Multiple logistic regression analyses were used to assess the association of video game playing and television viewing behavior with elbow or shoulder pain. RESULTS: Among the 210 players polled, 200 male players were included in the analysis. The prevalence of elbow or shoulder pain was 30.0%. Playing video games for ≥3 hours/day was significantly associated with elbow or shoulder pain vs. spending <1 hour/day playing video games (odds ratio, 5.59; 95% confidence interval, 1.44-21.64; P = .013). The amount of time spent watching television was not significantly associated with the prevalence of elbow or shoulder pain. CONCLUSIONS: Playing video games for ≥3 hours/day was associated with elbow or shoulder pain among elite young male baseball players. These findings highlight the effect of lifestyle on elbow and shoulder pain and should be taken into consideration by players, coaches, parents, and clinicians for the prevention of elbow and shoulder pain.

Asymmetric Cyanation of α-Ketimino Ester Derivatives with Chiral Ru-Li Combined Catalysts.

Asymmetric cyanation of α-ketimino esters catalyzed by combined systems of amino acid/BINAP derivative/Ru(II) complexes and lithium compounds was examined. The use of an appropriate combination of amino acid and BINAP ligands achieved high enantioselectivity for a variety of α-alkynyl (Val/XylBINAP/Ru), α-alkenyl (Val/TolBINAP/Ru), and α-aryl imino esters (Val/XylBINAP/Ru) as well as an isatin-derived cyclic imino amide (t-Leu/BINAP/Ru) to afford the α-cyano-α-amino esters and the amide with an α-nitrogen-substituted quaternary chiral center with up to 98% ee.

RSPO3 is a novel contraction-inducible factor identified in an "in vitro exercise model" using primary human myotubes.

The physiological significance of skeletal muscle as a secretory organ is now well known but we can only speculate as to the existence of as-yet-unidentified myokines, especially those upregulated in response to muscle contractile activity. We first attempted to establish an "insert-chamber based in vitro exercise model" allowing the miniature but high cell-density culture state enabling highly developed contractile human myotubes to be readily obtained by applying electric pulse stimulation (EPS). By employing this in vitro exercise model, we identified R-spondin 3 (RSPO3) as a novel contraction-inducible myokine produced by cultured human myotubes. Contraction-dependent muscular RSPO3 mRNA upregulation was confirmed in skeletal muscles of mice subjected to sciatic nerve mediated in situ contraction as well as those of mice after 2 h of running. Pharmacological in vitro experiments demonstrated a relatively high concentration of metformin (millimolar range) to suppress the contraction-inducible mRNA upregulation of human myokines including RSPO3, interleukin (IL)-6, IL-8 and CXCL1. Our data also suggest human RSPO3 to be a paracrine factor that may positively participate in the myogenesis processes of myoblasts and satellite cells. Thus, the "insert chamber-based in vitro exercise model" is a potentially valuable research tool for investigating contraction-inducible biological responses of human myotubes usually exhibiting poorer contractility development even in the setting of EPS treatment.

Tissue accumulation of neutrophil extracellular traps mediates muscle hyperalgesia in a mouse model.

Accumulation of uric acid (UA) during muscular trauma is a factor involved in the development of muscle hyperalgesia. Neutrophil extracellular traps (NETs), DNA-based reticular structures to capture UA, play a central role in the pain onset of gout attacks; however, the involvement of NETs via the elevation of local UA level in muscle hyperalgesia due to injuries from muscle overuse remains unknown. The triceps surae muscles (TSMs) in the unilateral hindlimb of mice were electrically stimulated to induce excessive muscle contraction. Mechanical withdrawal thresholds, tissue UA levels, neutrophil recruitment, and protein amount of citrullinated histone 3 (citH3), a major marker of NETs, were investigated. Furthermore, whether neutrophil depletion, extracellular DNA cleavage, and administration of the urate-lowering agent febuxostat improved muscle hyperalgesia caused by NET formation was examined. CitH3 expression upon neutrophil recruitment was significantly increased in the stimulated TSMs with increased tissue UA levels, whereas febuxostat administration improved muscle hyperalgesia with decreased citH3 and tissue UA levels, as observed in neutrophil depletion and extracellular DNA digestion. The underlying mechanism of muscle hyperalgesia associated with locally recruited neutrophils forming NETs due to increased tissue UA levels potentially plays a significant role in creating a vicious circle of muscle pain.

Validation and reliability of a Japanese version of the Simple Shoulder Test: a cross-sectional study.

BACKGROUND: The Simple Shoulder Test (SST) is a widely used patient-reported outcome assessment. The purpose of this study was to develop and validate a Japanese version of the SST (SST-Jp). METHODS: A two-stage observational study was conducted to validate the cross-cultural adaptation of the SST. A total of 100 patients with shoulder disorders completed the SST-Jp; the Disability of Arm, Shoulder, and Hand assessment; and the Medical Outcomes Short-Form 36 (SF-36) at an initial visit. Thirty-four of the patients repeated the SST-Jp one week after the first examination. The test-retest reliability was quantified using the interclass correlation coefficient, and Cronbach's alpha (α) was calculated to assess internal consistency. Construct validity was assessed using Spearman's rank correlation coefficient. RESULTS: The internal consistency of the SST-Jp was very high (α = 0.826). The interclass correlation coefficient of the SST-Jp was also high (0.859). There was a strong, positive correlation between the Disability of Arm, Shoulder, and Hand and the SST-Jp (r = 0.717, P < .001). The SST-Jp was significantly correlated with most of the SF-36 subscales. The correlations of the SST-Jp with physical subscales of the SF-36 were stronger than those with the other subscales. CONCLUSIONS: The SST-Jp was found to be a valid and reliable measurement for shoulder joint pain and function assessment among the Japanese population.

Low Back Pain in Young Sports Players: A Cross-sectional Study in Japan.

STUDY DESIGN: A cross-sectional study. OBJECTIVE: The purpose of this large cohort study was to assess the prevalence of low back pain (LBP) among young players participating in several types of sports. SUMMARY OF BACKGROUND DATA: LBP is a significant problem among young sports players. Sport discipline among young players is thought to be associated with LBP. However, similar previous studies did not specifically analyze LBP by age and sex. METHODS: A cross-sectional study was conducted with young sports players (ages 6-15 years, n = 7277) using a self-reported questionnaire. The prevalence of LBP was assessed using the variables of age, sex, and sport discipline. RESULTS: The point prevalence of LBP among young sports players was 5.0%. The participants between 6 and 8 years' old had the lowest prevalence of LBP (0.4%-1.3%), which increased with aging and reached the highest proportion of 13.5% to 14.8% at 13 to 14 years. Furthermore, female players had significantly higher proportions of LBP than male players (8.1% vs. 3.7%). Regarding sport discipline, the prevalence of LBP was higher in basketball, handball, and volleyball. CONCLUSION: The prevalence of LBP among young sports players was different for age, sex, and sport discipline. Further studies are needed to clarify the association of sport-specific movements to LBP in each sport discipline. This may assist in developing programs or strategies for preventing LBP among young sports players.Level of Evidence: 3.

A 5-year Longitudinal Study of Low Back Pain in Survivors of the Great East Japan Earthquake.

STUDY DESIGN: A longitudinal panel study. OBJECTIVE: The aim of this study was to examine the occurrence of low back pain (LBP), especially the association of previous LBP with further episodes of LBP, in survivors of the Great East Japan Earthquake (GEJE) during the course of 5 years. SUMMARY OF BACKGROUND DATA: LBP is common among survivors of natural disasters, but its long-term course is not clear. METHODS: A 5-year longitudinal study was conducted among survivors of the GEJE (n = 1821). The presence of LBP was assessed using a self-reported questionnaire at 2, 4, and 7 years after the disaster (termed the first, second, and third time points, respectively). Multiple logistic regression analysis was performed to assess a potential association between LBP at the first and second time points with LBP at the third time point, and the odds ratios (ORs) and 95% confidence intervals (CI) were calculated. RESULTS: The prevalence of LBP was 25.3%, 27.3%, and 27.2% at the first, second, and third time points, respectively. The occurrence of LBP at the first time point was significantly associated with LBP at the third time point, and the adjusted odds ratio (OR) (95% confidence interval [CI]) was 5.47 (4.28-6.98). Furthermore, LBP at the first and second time points was significantly associated with LBP at the third time point. Compared to no LBP at the first and second time points, the adjusted OR (95% CIs) for LBP at the third time point was 4.12 (3.14-5.41) in the case of LBP at either of the first or second time points and 10.73 (7.80-14.76) for LBP at both time points (P for trend < 0.001). CONCLUSION: Previous LBP was associated with LBP 5 years later among survivors of the GEJE. Furthermore, the effect on subsequent LBP was stronger with a higher frequency of previous LBP episodes.Level of Evidence: 3.

A new pathophysiology of atraumatic rotator cuff tears: adduction restriction of the glenohumeral joint.

BACKGROUND: The pathophysiology of atraumatic rotator cuff tears (ATTs) has not been fully understood. Adduction restriction of the glenohumeral joint can cause pain and disability in patients with ATTs. We aimed to use our adduction test (pushing the humerus toward the side in the coronal plane with scapular fixation) to fluoroscopically measure the glenohumeral adduction angle (GAA) and to assess the effectiveness of adduction manipulation. MATERIALS AND METHODS: Fifty-five patients with ATTs were included in the study. The GAAs of the patients vs. healthy subjects without ATTs were measured fluoroscopically and compared. During the test, patients showed restriction and expressed pain. The visual analog scale (VAS) score, passive range of motion (ROM), and the American Shoulder and Elbow Surgeons score at the initial visit were compared with those after adduction manipulation. RESULTS: Of the patients, 41 (75%) had positive adduction test results. A higher percentage of positive adduction test results was observed in smaller tears. The average GAA was -21.4° on the affected side, which was smaller than that on the unaffected side, at -2.8° (P < .001), and that in healthy subjects, at 4.8° (P < .001). After manipulation, the GAA was -0.8° (P < .001) and the VAS score, the American Shoulder and Elbow Surgeons score, and all ROM values significantly improved up to the level on the unaffected side. CONCLUSION: Adduction restriction of the glenohumeral joint was identified in 75% of all the patients with ATTs. Adduction manipulation significantly reduces the VAS score and restores the ROM. Adduction restriction is considered a crucial pathophysiology of ATTs.

Correlations between Capsular Changes and ROM Restriction in Frozen Shoulder Evaluated by Plain MRI and MR Arthrography.

BACKGROUND: Evaluation of the Range Of Motion (ROM) is one of the important procedures for shoulder disorders. The purpose of this study was to investigate correlations between capsular changes and ROM restrictions evaluated by both plain magnetic resonance imaging (MRI) and Magnetic Resonance Arthrography (MRA) in the same patients with frozen shoulder. METHODS: Between March 2015 and June 2016, 24 patients with frozen shoulders (13 male and 11 female patients, mean age 60.5) with severe ROM restriction who underwent both MRI and MRA on the same affected side were evaluated. We evaluated 1) ROM, 2) the coracohumeral ligament (CHL) thickness, 3) the joint capsule thickness in the axillary recess (humeral and glenoid sides), 4) the area of the axillary recess, and 5) the capsular area of the axillary recess. RESULTS: Positive correlations were found between the axillary area and forward flexion (FF) (R = 0.43, P = 0.035), lateral elevation (LE) (R = 0.66, P<0.001), external rotation (ER)(R = 0.43, P = 0.035), 90° abduction with external rotation (AER)(R = 0.56, P = 0.004), and hand behind the back (HBB)(R = 0.6, P = 0.002) on MRA. Negative correlations were found between the joint capsule at the glenoid side and ER and HBB in both MRI and MRA. CONCLUSION: The axillary area was significantly correlated with ROM restriction in FF, LE, ER, AER, and HBB on MRA. Thickness of the joint capsule at the glenoid side is an important factor for ROM restriction in frozen shoulder. LEVEL OF EVIDENCE: Level 3, Study of Diagnostic Test.

Total Synthesis of Biselide E, a Marine Polyketide.

The total synthesis of biselide E, a marine polyketide isolated from the Okinawan ascidian, has been accomplished. The highlight of this approach is the use of the ß-elimination reaction of the chloroacetoxy group for the construction of an unstable six-membered α,ß,γ,δ-unsaturated lactone portion at the late stage of the total synthesis.

A Thickened Coracohumeral Ligament and Superomedial Capsule Limit Internal Rotation of the Shoulder Joint: Report of Three Cases.

Adhesive capsulitis of the shoulder (also known as frozen shoulder) is a painful and disabling disorder with an estimated prevalence ranging from 2% to 5% in the general population. Although the precise pathogenesis of frozen shoulder is unclear, thickened capsule and coracohumeral ligament (CHL) have been documented to be one of the most specific manifestations. The thickened CHL has been understood to limit external rotation of the shoulder, and restriction of internal rotation of the shoulder has been believed to be related to posterior capsular tightness. In this paper, three cases of refractory frozen shoulder treated through arthroscopic release of a contracted capsule including CHL were reported. Two cases in which there is recalcitrant severe restriction of internal rotation after manipulation under anesthesia (MUA) were finally treated with arthroscopic surgery. Although MUA could release the posterior capsule, internal rotation did not improve in our cases. After release of the thickened CHL, range of motion of internal rotation was significantly improved. This report demonstrates the role of the thickened CHL in limiting the internal rotation of the shoulder. We highlight the importance of release of thickened CHL in addition to the pancapsular release, in case of severe limitation of internal rotation of shoulder.