Ultrasonographic Evaluation of the Shoulders and Its Associations with Shoulder Pain, Age, and Swim Training in Masters Swimmers

Do therapeutic exercises impact supraspinatus tendon thickness? Secondary analyses of the combined dataset from two randomized controlled trials in patients with rotator cuff-related shoulder pain

BACKGROUND

The mechanistic response of rotator cuff tendons to exercises within the context of rotator cuff-related shoulder pain (RCRSP) remains a significant gap in current research. A greater understanding of this response can shed light on why individuals exhibit varying responses to exercise interventions. It can also provide information on the influence of certain types of exercise on tendons. The primary aim of this article is to explore if changes in supraspinatus tendon thickness (SSTT) ratio differ between exercise interventions (high load vs. low load). The secondary aims are to explore if changes in SSTT ratio differ between ultrasonographic tendinopathy subgroups (reactive vs. degenerative) and if there are associations between tendinopathy subgroups, changes in tendon thickness ratio, and clinical outcomes (disability).

METHODS

This study comprises secondary analyses of the combined dataset from two randomized controlled trials that compared high and low-load exercises in patients with RCRSP. In those trials, different exercise interventions were compared: 1) progressive high-load strengthening exercises and 2) low-load strengthening with or without motor control exercises. In 1 trial, there was also a third group that was not allocated to exercises (education only). Ultrasound-assessed SSTT ratio, derived from comparing symptomatic and asymptomatic sides, served as the primary measure in categorizing participants into tendinopathy subgroups (reactive, normal and degenerative) at baseline.

RESULTS

Data from 159 participants were analyzed. Two-way repeated measures ANOVAs revealed significant Group (P < .001) and Group × Time interaction (P < .001) effects for the SSTT ratio in different tendinopathy subgroups, but no Time effect (P = .63). Following the interventions, SSTT ratio increased in the "Degenerative" subgroup (0.14 [95% confidence interval {CI}: 0.09-0.19]), decreased in the "Reactive" subgroup (-0.11 [95% CI: -0.16 to -0.06]), and remained unchanged in the "Normal" subgroup (-0.01 [95% CI: -0.04 to 0.02]). There was no Time (P = .21), Group (P = .61), or Group × Time interaction (P = .66) effect for the SSTT ratio based on intervention allocation. Results of the linear regression did not highlight any significant association between the tendinopathy subgroup (P = .25) or change in SSTT ratio (P = .40) and change in disability score.

CONCLUSION

Findings from this study suggest that, over time, SSTT in individuals with RCRSP tends to normalize, compared to the contralateral side, regardless of the exercise intervention. Different subgroups of symptomatic tendons behave differently, emphasizing the need to potentially consider tendinopathy subtypes in RCRSP research. Future adequately powered studies should investigate how those different tendinopathy subgroups may predict long-term clinical outcomes.

Shoulder structures and strength in competitive preadolescent swimmers: A longitudinal ultrasonographic study

BACKGROUND

Repetitive shoulder movements during competitive training may cause changes in the strength of periarticular shoulder structures in preadolescent swimmers.

OBJECTIVE

To prospectively determine the effects of training on shoulder periarticular structures and muscle strength in preadolescent swimmers.

DESIGN

Prospective cohort study.

SETTING

Community-based natatorium.

PARTICIPANTS

Twenty-four preadolescent swimmers aged 10-12 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Measurements were repeated in three periods as preseason, midseason, and postseason. Ultrasonographic measurements (supraspinatus tendon thickness, humeral head cartilage thickness, deltoid muscle thickness, and acromiohumeral distance) were performed using a portable device and a linear probe. Shoulder (flexion, extension, abduction, internal and external rotation) and back (serratus anterior, lower, and middle trapezius) isometric muscle strength were measured with a handheld dynamometer.

RESULTS

Supraspinatus tendon thickness and acromiohumeral distance were similar in all periods (all p > .05); however, deltoid muscle and humeral head cartilage thicknesses increased throughout the season (p = .002, p = .008, respectively). Likewise, whereas shoulder muscle strength increased (all p < .05), back muscle strength was similar in all periods (all p > .05).

CONCLUSIONS

In preadolescent swimmers, acromiohumeral distance and supraspinatus tendon thickness seem to not change; but humeral head cartilage and deltoid muscle thicknesses as well as shoulder muscle strength increase throughout the season.

Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

Self-reported bio-psycho-social factors partially distinguish rotator cuff tendinopathy from other shoulder problems and explain shoulder severity: A case-control study

OBJECTIVE

Examine how rotator cuff (RC) tendinopathy differed from other shoulder problems (OSP) by measuring a variety of self-reported bio-psycho-social factors, and establish which explain severity.

METHODS

A validated online survey battery was used to collect self-reported biopsychosocial variables in an international population. Diagnostic group and severity were the dependent variables. Multiple logistic and linear regression analyses were utilised to generate explanatory models for group differences and severity after group comparison and univariate regression analysis.

RESULTS

82 people with RC tendinopathy (50 female, 42.8 ± 13.9 years) and 54 with OSP (33 female, 40.2 ± 14.1 years) were recruited. Both groups had comparable severity results (Shoulder Pain and Disability Index = 37.3 ± 24.5 vs. 33.7 ± 22.5). Seven factors individually differentiated RC tendinopathy from OSP. The multivariable model included 4 factors: activity effect on pain (OR(95%CI) = 2.24(1.02-4.90)), previous injury in the shoulder (OR(95% CI) = 0.30(0.13-0.69)), activity level (moderate OR(95% CI) = 3.97(1.29-12.18), high OR(95% CI) = 3.66(1.41-9.48)) and self-efficacy (OR(95%CI) = 1.12(1.02-1.22)) demonstrating acceptable accuracy. The second multivariable model for RC tendinopathy severity included one demographic, three psychological and two biomedical variables (β(range) = 0.19-0.38) and explained 68% of the variance.

CONCLUSION

Self-reported bio-psycho-social variables may be beneficial for further detailed clinical assessment as they partially distinguish RC tendinopathy from OSP, even when the groups have comparable overall pain and functional problems. Moreover, these variables were shown to be substantially associated with RC tendinopathy severity variance, implying that the clinical evaluation might be improved, perhaps by pre-consultation online data collection. The models should be validated in the future and considered alongside data from physical and imaging examinations.

Investigating The Association Between Supraspinatus Tendon Abnormality, Shoulder Pain and Isokinetic Strength in Elite Swimmers: A Cross-Sectional Study

Shoulder pain is common among elite swimmers due to the tremendous stress over shoulders during swimming. Supraspinatus muscle is one of the major prime movers and stabilizers of shoulder and is highly susceptible to overloading and tendinopathy. An understanding of the relationship between supraspinatus tendon and pain; and between supraspinatus tendon and strength would assist health care practitioners for developing training regime. The objectives of this study are to evaluate 1) the association between structural abnormality of supraspinatus tendon and shoulder pain and 2) the association between structural abnormality of supraspinatus tendon and shoulder strength. We hypothesized that structural abnormality of supraspinatus tendons positively associated with shoulder pain and negatively associated with shoulder muscle strength among elite swimmers. 44 elite swimmers were recruited from the Hong Kong China Swimming Association. Supraspinatus tendon condition was evaluated using diagnostic ultrasound imaging and shoulder internal and external rotation strength was evaluated by the isokinetic dynamometer. Pearson's R was used to study the correlation between shoulder pain and supraspinatus tendon condition and to evaluate the association between isokinetic strength of shoulders and supraspinatus tendon condition. 82 shoulders had supraspinatus tendinopathy or tendon tear (93.18%). However, there was no statistically significant association between structural abnormality of supraspinatus tendon and shoulder pain. The results showed that there was no association between supraspinatus tendon abnormality and shoulder pain and there was a significant correlation between left maximal supraspinatus tendon thickness (LMSTT) and left external rotation/ concentric (LER/Con) and left external rotation/ eccentric (LER/Ecc) shoulder strength (p < 0.05) while internal rotation/ external rotation (IR/ER) ratio can also be a significant predicator on LMSTT >6mm (R² = 0.462, F = 7.016, df = 1, p = 0.038). Structural change of supraspinatus tendon was not associated with shoulder pain, but could be a predictor on MSTT >6mm in elite swimmers.