Risk factors for shoulder osteoarthritis with rotator cuff tear in the elderly general population.

HYPOTHESIS AND/OR BACKGROUND: The relationship between shoulder osteoarthritis (OA) and rotator cuff tear (RCT) is unclear. We hypothesized that there is a difference between the pathogenesis of OA complicating RCT and that of RCT complicating OA. In this study, our primary objective was to determine the prevalence of shoulder OA without RCT, RCT without OA, and OA with RCT in the general older population. Our secondary objective was to identify risk factors for the association with OA+RCT in shoulder OA alone or RCT alone, respectively. METHODS: We enrolled patients from the public health checkup conducted in Gunma prefecture (Japan) in 2014. Subjects' shoulder pain at rest, during motion, and at night was evaluated using a questionnaire. Moreover, active and passive range of motions (ROMs) in flexion, abduction, and external rotation were measured. For RCT parameters, we evaluated as no tear, partial-thickness supraspinatus (SSP) tear, full-thickness SSP tear, and SSP-infraspinatus tears. For further analysis, the shoulders were divided into three groups according to the presence of RCT and/or OA: OA, RCT, and OA + RCT groups. Risk factors for OA + RCT were identified in a logistic regression analysis. RESULTS: Overall, 944 of 1148 shoulders were eligible for inclusion. The prevalence rates of shoulder OA, RCT, and OA + RCT were 5.8%, 21.1%, and 4.2%, respectively. Furthermore, 650 shoulders were excluded, and 55, 199, and 40 shoulders had OA, RCT, and OA + RCT, respectively. There were significant differences for age, ROM of active external rotation, strength of abduction, external rotation, and morphology of the rotator tears. However, there were no significant differences for pain visual analog scale score, passive ROM, Simple Shoulder Test, and grades of OA. Older age decreased active ROM in external rotation, and the presence of both subscapularis and SSP-infraspinatus tears was a risk factor for the association of OA with an RCT shoulder. Older age, weaker power in external rotation, and affected dominant side were risk factors for the association of RCT with an OA shoulder. DISCUSSION AND/OR CONCLUSION: This study is the first to report risk factors by considering both shoulder OA and RCT in the general population. Our findings will be useful for the treatment and management of OA and RCT as well as for the prevention of these conditions in the older adults.

Intraoperative neuromonitoring during reverse shoulder arthroplasty.

BACKGROUND: The aim of this study was to evaluate the risk of nerve injury with neuromonitoring during reverse total shoulder arthroplasty. MATERIALS: This study included 15 shoulders of 15 patients (11 females and 4 males) who underwent reverse total shoulder arthroplasty. The mean age was 74.8 ± 4.4 years. Nine shoulders had cuff tear arthropathy, 4 had massive rotator cuff tears, 2 had osteoarthritis, and 1 had rheumatoid arthritis. The somatosensory evoked potentials of the median nerve, transcranial motor evoked potentials, and free-electromyograms from 6 upper-extremity muscles were measured intraoperatively. We defined a nerve alert as 50% amplitude attenuation or 10% latency prolongation of the somatosensory evoked potentials and transcranial motor evoked potentials and sustained neurotonic discharge on free-electromyogram. RESULTS: Thirty-one alerts were recorded in 11 patients. The axillary nerve was associated with 17 alerts. Eleven alerts occurred during the glenoid procedure and 5 alerts occurred during the humeral procedure. One patient who did not recover from the alert of the axillary nerve had clinically incomplete paralysis of the deltoid muscle. CONCLUSION: The present findings suggest that the axillary nerve was the nerve most frequently exposed to the risk of injury, especially during glenoid and humeral implantation.

What Is the Appropriate Reference for Evaluating the Recovery of Supraspinatus Muscle Atrophy After Arthroscopic Rotator Cuff Repair? The Occupation Ratio of the Supraspinatus May Change After Rotator Cuff Repair Without Volumetric Improvement.

BACKGROUND: Supraspinatus muscle atrophy is typically assessed by the occupation ratio of the cross-sectional area of the muscle belly to the supraspinatus fossa at the medial border of the coracoid process in a slice along the oblique-sagittal plane on MRI. Previous studies have shown that the occupation ratio of the supraspinatus changed soon after rotator cuff repair compared with before surgery. However, no studies have examined the perioperative change in the muscle volume assessed with 3-dimensional measurement. PURPOSE: To compare the volume of the supraspinatus muscle before and soon after surgery by using 3-dimensional imaging and to elucidate whether the changes in the occupation ratio represent corresponding changes in the muscle volume. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Thirty shoulders of patients who underwent arthroscopic rotator cuff repair were evaluated. T2-weighted images were obtained before surgery and 2 weeks after surgery. After the muscle and its tendon borders were plotted, the supraspinatus and its tendon were segmented with interactive thresholding in all slices. The 3-dimensional images were then reconstructed and the volumes calculated. Changes in the muscle volume and the occupation ratio were evaluated via 3-dimensional and 2-dimensional image assessments. The 3-dimensional and 2-dimensional findings before and after surgery were compared by use of paired t tests. RESULTS: The mean muscle volume did not change significantly at a time point soon after surgery in any group. In patients with little medial retraction (n = 7) or isolated detachment at the superior facet (n = 17), no significant differences were noted in the occupation ratio after surgery compared with before surgery. In contrast, in patients with moderate medial retraction (n = 23) or extended tearing in the transverse direction (n = 13), the occupation ratio increased significantly. CONCLUSION: Although the muscle volume did not change soon after surgery compared with the preoperative values, in patients with moderate medial retraction or extended tearing in the transverse direction, the occupation ratio increased, probably due to lateral traction of the supraspinatus muscle. We recommend that MRI findings obtained soon after surgery be used as the time-zero reference for evaluating the postoperative changes in the supraspinatus.

Shoulder Stretching Intervention Reduces the Incidence of Shoulder and Elbow Injuries in High School Baseball Players: a Time-to-Event Analysis.

We prospectively evaluated the effects of a prevention program on the incidence of shoulder and elbow injuries in high school baseball pitchers. Ninety-two pitchers participated in this study and were taught to perform stretching and strength exercises aimed at improving shoulder external rotation strength in the preseason. The pitchers freely chose to participate in one of four groups [SM-group: performed both exercises, S-group: performed stretching exercise only, M-group: performed strength training only, and N-group: performed neither intervention]. Injury was defined as inability to play for ≥8 days because of shoulder/elbow symptoms. Kaplan-Meier survival curves were generated and hazard ratios (HRs) for injury occurrence were calculated using multivariate Cox regression. Log-rank test was used for between-group comparisons of survival distributions. The injuries occurred in 25, 35, and 57% of participants and median times to injury were 89, 92, and 29.5 days in the S- (n = 32), SM- (n = 46), and N- (n = 14) group, respectively. Nobody chose M-group. HRs were 0.36 and 0.47 for the S- and SM-group, respectively, based on the N-group. The incidence of injury was significantly lower in the S-group than in the N-group (p = 0.04). Daily posterior shoulder stretching may reduce the incidence of the injuries in high school baseball pitchers.

Does successful rotator cuff repair improve muscle atrophy and fatty infiltration of the rotator cuff? A retrospective magnetic resonance imaging study performed shortly after surgery as a reference.

BACKGROUND: Muscle atrophy and fatty infiltration in the rotator cuff muscles are often observed in patients with chronic rotator cuff tears. The recovery from these conditions has not been clarified. METHODS: Ninety-four patients were included in this study. The improvement in muscle atrophy and fatty infiltration in successfully repaired rotator cuff tears was evaluated by magnetic resonance imaging at 1 year and 2 years after surgery and was compared with muscle atrophy and fatty infiltration observed on magnetic resonance imaging at 2 weeks after surgery to discount any changes due to the medial retraction of the torn tendon. The patients' muscle strength was evaluated in abduction and external rotation. RESULTS: Muscle atrophy and fatty infiltration of the supraspinatus were significantly improved at 2 years after surgery in comparison to 2 weeks after surgery. The subjects' abduction and external rotation strength was also significantly improved at 2 years after surgery in comparison to the preoperative values. Patients whose occupation ratio was improved had a better abduction range of motion, stronger abduction strength, and higher Constant score. Patients whose fatty infiltration was improved had a better range of motion in flexion and abduction, whereas the improvements of muscle strength and the Constant score were similar in the group that showed an improvement of fatty infiltration and the group that did not. CONCLUSION: Muscle atrophy and fatty infiltration can improve after rotator cuff repair. The strengths of abduction and external rotation were also improved at 2 years after surgery.

Prospective multifactorial analysis of preseason risk factors for shoulder and elbow injuries in high school baseball pitchers.

PURPOSE: To prospectively identify preseason physical factors for shoulder and elbow injuries during the season in high school baseball pitchers. METHODS: The study included 105 high school baseball pitchers [median age 16 (15-17) years]. The range of motion of the shoulder (90° abducted external and internal rotation) and elbow (extension/flexion), shoulder muscle strength (abduction and prone internal and external rotation), shoulder and elbow laxity, horizontal flexion, and scapular dyskinesis were assessed. After the season, the participants completed questionnaires regarding shoulder and/or elbow injuries, with injury defined as an inability to play for ≥1 week due to elbow/shoulder problems. The results of two groups (injured and noninjured) were compared using t tests and Chi-square analyses. Stepwise forward logistic regression models were developed to identify risk factors. RESULTS: Twenty-one injuries were observed. In univariate analysis, 90° abducted internal rotation and total arc of the dominant shoulder and the ratio of prone external rotation in the dominant to nondominant sides in the injured group were significantly less than those in the noninjured group (P = 0.02, 0.04, and 0.01, respectively). In logistic regression analysis, 90° abducted internal rotation in the dominant shoulder and prone external rotation ratio were significantly associated with injuries (P = 0.02 and 0.03, respectively). CONCLUSION: A low prone external rotation ratio and decreased 90° abducted internal rotation in the dominant shoulder in the preseason were significant risk factors for shoulder and elbow injuries in high school baseball pitchers. The results may contribute to reduce the incidence of these injuries. LEVEL OF EVIDENCE: II.

Shoulder pain and intra-articular interleukin-8 levels in patients with rotator cuff tears.

AIM: Rotator cuff disease (RCD) is one of the most common disorders in the shoulder joint and causes joint pain and functional disability. In this study, we investigated the associations among cytokine levels and clinical symptoms in patients with RCD. METHOD: Joint fluid specimens of the shoulder joint were obtained from 38 patients with RCD before arthroscopic surgery. The levels of inflammatory cytokines, including interleukin (IL)-1ß, IL-6 and IL-8, were evaluated using enzyme-linked immunosorbent assay kits, and the associations between these cytokine levels and the clinical symptoms were determined. A multiple linear regression analysis was performed to identify the parameters accounting for the visual analogue scale (VAS) score at rest. RESULTS: IL-8 level was correlated with IL-6 (r = 0.434, P = 0.006) and IL-1ß (r = 0.575, P < 0.001) levels. The cuff tear size was inversely correlated with the VAS score at rest. A multiple stepwise linear regression analysis revealed that the VAS score at rest could be explained by the VAS score at night, the VAS score during movement and the intra-articular IL-8 level (adjusted R² = 0.544, P < 0.001). The intra-articular IL-8 level is associated with resting pain in rotator cuff tear patients. CONCLUSION: These results suggest that an increased concentration of IL-8 is associated with resting pain in rotator cuff tear patients.

Clinical Outcome of Arthroscopic Remplissage as Augmentation During Arthroscopic Bankart Repair for Recurrent Anterior Shoulder Instability.

PURPOSE: We aimed to assess functional outcomes and postoperative recurrence rate associated with the remplissage procedure used for bone augmentation with Bankart repair in patients with Hill-Sachs lesions after shoulder dislocation. METHODS: Preoperative computed tomography was performed to check for bony Bankart lesions,calculate the bone defect rate, and estimate the risk for re-dislocation. Functional and clinical scores were assessed preoperatively and at three months, six months, and one year postoperatively. RESULTS: Between 2011 and 2014, 18 patients (17 male; age at surgery, 29.0±10.4 years; 18 affected shoulders) underwent arthroscopic Bankart repair with arthroscopic remplissage (remplissage group), and 18 sex- and age-matched controls underwent arthroscopic Bankart repair alone (control group). The incidence of bony Bankart lesion and glenoid bone defect was significantly higher in the remplissage group. No complications, re-dislocation, or re-subluxation was noted during or after the operation. Postoperatively, the range of motion and muscular weakness alleviated with time, and the clinical scores improved significantly from the preoperative values. However, the remplissage group showed significantly restricted shoulder flexion, abduction, internal rotation and external rotation even at one year postoperatively. Compared to the control group, the remplissage group showed significantly lower Rowe scores preoperatively, and both Rowe scores and University of California-Los Angeles scale scores remained significantly lower throughout the one-year follow-up. CONCLUSION: Despite some restriction of external rotation, remplissage leads to better clinical scores and no recurrence, providing a valid means of augmentation for Bankart repair in high-risk patients with engaged Hill-Sachs lesion.

The Neural Correlates of Shoulder Apprehension: A Functional MRI Study.

Although shoulder apprehension is an established clinical finding and is important for the prevention of shoulder dislocation, how this subjective perception is evoked remains unclear. We elucidated the functional neuroplasticity associated with apprehension in patients with recurrent anterior shoulder instability (RSI) using functional magnetic resonance imaging (fMRI). Twelve healthy volunteers and 14 patients with right-sided RSI performed a motor imagery task and a passive shoulder motion task. Brain activity was compared between healthy participants and those with RSI and was correlated with the apprehension intensity reported by participants after each task. Compared to healthy volunteers, participants with RSI exhibited decreased brain activity in the motor network, but increased activity in the hippocampus and amygdala. During the passive motion task, participants with RSI exhibited decreased activity in the left premotor and primary motor/somatosensory areas. Furthermore, brain activity was correlated with apprehension intensity in the left amygdala and left thalamus during the motor imagery task (memory-induced), while a correlation between apprehension intensity and brain activity was found in the left prefrontal cortex during the passive motion task (instability-induced). Our findings provide insight into the pathophysiology of RSI by identifying its associated neural alterations. We elucidated that shoulder apprehension was induced by two different factors, namely instability and memory.

The impact of faulty posture on rotator cuff tears with and without symptoms.

HYPOTHESIS: We hypothesized that the prevalence of rotator cuff tears would be higher among individuals with poor posture, regardless of the presence of symptoms. METHODS: The study initially comprised 525 residents of a mountain village who participated in an annual health check. Participants completed a background questionnaire, and physical examinations were performed to evaluate shoulder function. Ultrasonographic examinations were also performed to identify rotator cuff tears, and participants were grouped according to the presence or absence of tears. Posture was classified by 2 observers into 4 types according to the classification of Kendall, as follows: ideal alignment, kyphotic-lordotic posture, flat-back posture, and sway-back posture. Univariate analyses were performed to compare differences in background characteristics between groups, then multivariate analysis was performed to identify those factors associated with rotator cuff tears. RESULTS: Final analysis was performed for 379 participants (135 men, 244 women; mean age, 62.0 years; range, 31-94 years) showing the same posture classification from both observers. Of these, 93 (24.5%) showed rotator cuff tear in one shoulder and 45 (11.9%) showed tears in both. Prevalence of rotator cuff tears was 2.9% with ideal alignment, 65.8% with kyphotic-lordotic posture, 54.3% with flat-back posture, and 48.9% with sway-back posture. Logistic regression analysis identified increased age, abnormal posture, and past pain as factors associated with rotator cuff tears. CONCLUSIONS: Postural abnormality represented an independent predictor of both symptomatic and asymptomatic rotator cuff tears. These results may help define preventive measures for rotator cuff tears and in design ing rehabilitation therapies for shoulder disease.

Prevalence of and risk factors for shoulder osteoarthritis in Japanese middle-aged and elderly populations.

BACKGROUND: The purpose of this study was to determine the prevalence of shoulder osteoarthritis (OA) in populations older than 40 years and to examine risk factors and the relationship with shoulder function. METHODS: The respondents in this study consisted of 541 patients who underwent general medical examinations in April 2012 as residents of a single village. The mean age was 65.2 ± 11.0 years (range, 40-89 years), and 341 (63.0%) of the respondents were women. Anteroposterior radiographs of the bilateral shoulder joints were obtained, and the subjects were classified into 3 groups (non-OA, mild OA, and moderate-severe OA) according to the Samilson-Prieto method. With respect to risk factors for shoulder OA, a logistic regression analysis was performed. RESULTS: Shoulder OA was detected in 17.4% (94 of 541) of the patients. The incidence of OA in both shoulders was 3.1% (17 of 541), and the prevalence of shoulder OA among the respondents 65 years of age or older (20.3%) was significantly higher than that observed among the respondents younger than 65 years (11.1%). The risk of shoulder OA increased according to age, with an odds ratio of 5.59 in the respondents 60 to 69 years of age (P = .027), 11.59 in the respondents 70 to 79 years of age (P = .004), and 10.77 in the respondents 80 years of age and older (P = .004). CONCLUSIONS: The prevalence of shoulder OA was 17.4%, and the risk factor for shoulder OA was age.

The effects of rotator cuff tears, including shoulders without pain, on activities of daily living in the general population.

BACKGROUND: Few reports have so far evaluated the possible restrictions of activities of daily living (ADL) in patients with asymptomatic rotator cuff tears (RCTs). The purpose of this study was to examine the effects of RCTs, including shoulders without pain, on ADL in the general population. METHODS: We performed medical checkups on 462 individuals (924 shoulders). All participants completed a questionnaire regarding their background and medical history. We then assessed their shoulder functions with the Simple Shoulder Test (SST) and performed US (US) examinations of both shoulders to diagnose RCTs. We divided participants into tear and nontear groups and performed statistical analysis to compare total SST scores and each SST item between groups. Furthermore, we performed the same examinations for participants identified as having shoulders without pain. RESULTS: Among participants, those in the tear group showed significantly lower total SST scores than those in the nontear group. After examining each SST item, a significant difference was observed regarding the ability to sleep comfortably and to lift 3.6 kg to shoulder level. In shoulders without pain, the tear group showed significantly lower total SST scores than the nontear group. A significant difference was observed only regarding the ability to lift 3.6 kg to shoulder level. CONCLUSIONS: In the general population, ADL were restricted in participants with RCTs; they experienced night pain in the shoulder and muscle weakness during shoulder elevation. Furthermore, participants with RCTs, even if the condition itself did not induce any pain, tended to experience muscle weakness during shoulder elevation, thus resulting in restrictions of ADL.

Characteristics of neck and shoulder pain (called katakori in Japanese) among members of the nursing staff.

BACKGROUND: The characteristics of neck and shoulder pain (NSP), called katakori in Japanese, have not been well documented to date. The aim of this study was to clarify the characteristics of NSP through a questionnaire survey of members of the nursing staff. METHODS: The study population consisted of 484 nursing staff members of Gunma University Hospital in Japan. The questionnaire involved information on age, body mass index (BMI), gender, psychological stress at work, musculoskeletal pain at other anatomic sites (elbow/wrist, lumbar and knee), smoking history, and hypertension. If subjects had NSP, they were asked about any coexisting symptoms, the utilization of health services, and the precise location of NSP. RESULTS: The total study population included 393 persons after 91 persons were excluded for various reasons. The point prevalence of NSP was 68.1% (268 of 393). Age, BMI, smoking history, and hypertension showed no significant trend for the prevalence of NSP in the univariate analyses. The occurrence of NSP was significantly higher in subjects with psychological stress, elbow/wrist pain, lumbar pain, and knee pain, respectively. A multivariate logistic regression analysis showed that gender, psychological stress, elbow/wrist pain, and lumbar pain were significantly associated with the occurrence of NSP. One hundred fifty-eight of those with NSP (58.9%) reported coexisting symptoms, and the most common was headache. Fifty-seven (21.2%) of the subjects with NSP had consulted medical or health practitioners, and bone setting was the most common service provider. The most common area of NSP was the superior part of the trapezius. CONCLUSIONS: This study confirmed that NSP, katakori in Japanese, is a prevalent problem in a nursing staff, and several factors associated with NSP were identified.

Factors involved in the presence of symptoms associated with rotator cuff tears: a comparison of asymptomatic and symptomatic rotator cuff tears in the general population.

BACKGROUND: The mechanisms underlying symptom development in rotator cuff tears are still unknown. The purpose of this study was to identify the characteristics associated with symptoms of rotator cuff tears. MATERIALS AND METHODS: We performed a medical checkup on residents of a mountain village. The subjects of this study included 211 individuals with 283 shoulders in which a full-thickness rotator cuff tear was observed through ultrasonography. We recorded the subjects' background and medical history and then performed physical examinations. The subjects were divided into 2 groups according to whether they had any pain or disabilities that they felt subjectively while performing their usual daily activities. We determined the prevalence of an asymptomatic rotator cuff tear and conducted a statistical analysis to compare any differences between the 2 groups. RESULTS: Of the 283 subjects, 65.4% with rotator cuff tears had no symptoms involving the shoulder. Asymptomatic rotator cuff tears were associated with a tear in the nondominant arm, a negative impingement sign, higher active forward elevation, and intact muscle strength in abduction and external rotation. A logistic regression analysis showed that a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm were significantly associated with the presence of symptoms of rotator cuff tears. CONCLUSIONS: In the general population, in approximately two-thirds of all rotator cuff tears, there are no symptoms, and the factors involved in the presence of symptoms associated with rotator cuff tears were identified to be a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm.

Prevalence and risk factors of a rotator cuff tear in the general population.

BACKGROUND: Little information is available about the epidemiology of rotator cuff tears in a population-based study. The purpose of this study was to elucidate the true prevalence of rotator cuff tears regardless of the presence or absence of symptoms in the general population and to assess the relationship between tears and their backgrounds. MATERIAL AND METHODS: A medical check-up was conducted for residents of a mountain village in Japan. The subjects consisted of 683 people (total of 1,366 shoulders), including 229 males and 454 females with a mean age of 57.9 years (range, 22-87). We examined their background factors, physical examinations and ultrasonographic examinations on both shoulders. RESULTS: Rotator cuff tears were present in 20.7% and the prevalence increased with age. Thirty-six percent of the subjects with current symptoms had rotator cuff tears, while 16.9% of the subjects without symptoms also had rotator cuff tears. Rotator cuff tears in the general population were most commonly associated with elderly patients, males, affected the dominant arm, engaged in heavy labor, having a history of trauma, positive for impingement sign, showed lesser active forward elevation and weaker muscle strength in abduction and external rotation. A logistic regression analysis revealed the risk factors for a rotator cuff tear to be a history of trauma, dominant arm and age. CONCLUSION: 20.7% of 1,366 shoulders had full-thickness rotator cuff tears in the general population. The risk factors for rotator cuff tear included a history of trauma, dominant arm and age. LEVEL OF EVIDENCE: Level 3.

Multivariate analysis of biochemical markers in synovial fluid from the shoulder joint for diagnosis of rotator cuff tears.

Multivariate discriminant analysis allowed definition of cytokine, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) levels in synovial fluid (SF) of patients with rotator cuff tears and other shoulder lesions. We analyzed SF aspirated from the glenohumeral joints of 17 patients with rotator cuff tears; SF from nine patients with other shoulder lesions was used to characterize a non-rotator-cuff-tear (NRCT) group. Discriminant analysis demonstrated statistically significant differences in (1) the determination of whether rotator cuff tear patients are separable from the NRCT group using the influential functions, the most influential of which were interleukin 1-beta, MMP-2, and MMP-13, and (2) the assessment of whether full-thickness rotator cuff tears are distinguishable from partial tears using identical influential functions. The most influential function in the latter analysis was MMP-13. Both interleukin 1-beta and MMP-13 might be biochemical markers of impending rotator cuff tears.