Effect of critical shoulder angle on deltoid muscle strength reduction in patients with rotator cuff tears / 中国修复重建外科杂志

OBJECTIVE@#To investigate the synergistic interaction between the deltoid muscle and the rotator cuff muscle group in patients with rotator cuff tears (RCT), as well as the impact of the critical shoulder angle (CSA) on deltoid muscle strength.@*METHODS@#A retrospective analysis was conducted on clinical data from 42 RCT patients who met the selection criteria and were treated between March 2022 and March 2023. There were 13 males and 29 females, with an age range of 42-77 years (mean, 60.5 years). Preoperative visual analogue scale (VAS) score was 6.0±1.6. CSA measurements were obtained from standard anteroposterior X-ray films before operation, and patients were divided into two groups based on CSA measurements: CSA>35° group (group A) and CSA≤35° group (group B). Handheld dynamometry was used to measure the muscle strength of various muscle group in the shoulder (including the supraspinatus, infraspinatus, subscapularis, and anterior, middle, and posterior bundles of the deltoid). The muscle strength of the unaffected side was compared to the affected side, and muscle imbalance indices were calculated. Muscle imbalance indices between male and female patients, dominant and non-dominant sides, and groups A and B were compared. Pearson correlation analysis was used to examine the relationship between muscle imbalance indices and CSA as well as VAS scores.@*RESULTS@#Muscle strength in all muscle groups on the affected side was significantly lower than on the unaffected side ( P<0.05). The muscle imbalance indices for the supraspinatus, subscapularis, infraspinatus, and anterior, middle, and posterior bundles of the deltoid were 14.8%±24.4%, 5.9%±9.7%, 7.2% (0, 9.1%), 17.2% (5.9%, 26.9%), 8.3%±21.3%, and 10.2% (2.8%, 15.4%), respectively. The muscle imbalance indices of the anterior bundle of the deltoid, supraspinatus, and infraspinatus were significantly lower in male patients compared to female patients ( P<0.05); however, there was no significant difference in muscle imbalance indices among other muscle groups between male and female patients or between the dominant and non-dominant sides ( P>0.05). There was a positive correlation between the muscle imbalance indices of infraspinatus and VAS score ( P<0.05), and a positive correlation between CSA and the muscle imbalance indices of middle bundle of deltoid ( P<0.05). There was no correlation between the muscle imbalance indices of other muscle groups and VAS score or CSA ( P>0.05). Preoperative CSA ranged from 17.6° to 39.4°, with a mean of 31.1°. There were 9 cases in group A and 33 cases in group B. The muscle imbalance indices of the anterior bundle of the deltoid was significantly lower in group A compared to group B ( P<0.05), while there was no significant difference in muscle imbalance indices among other muscle groups between group A and group B ( P>0.05).@*CONCLUSION@#Patients with RCT have a phenomenon of deltoid muscle strength reduction, which is more pronounced in the population with a larger CSA.

Correlation of scapulothoracic muscle strength and functional activity in volleyball players

Background:Volleyball is the game in which upper extremities are mostly involved. This game needs repeated forceful high-speed upper limb activities required during training sessions and matches; which are reported to high incidence of shoulder injuries. This study is to correlate scapulothoracic muscle strength and functional activity in volleyball players.Methods:Study is cross sectional;correlational study was done with convenient sampling. Sample size was 55. Subjects were selected from all over Pune. Scapulothoracic muscles strength was measured (using the handheld dynamometer) in volleyball players which fitted in the inclusion and exclusion criteria and filleddisabilities of the arm, shoulder and hand (DASH)scale by every participantincluded in study. Correlated evaluated data using spearman rho method.Results:Study shows that all muscle carry good strength. Statistical analysis shows no significance, p value for all tested muscle is (p>0.05). Also DASHscale shows lesser score which indicates lesser difficulty to do functional activities.Conclusions:This study proves that there is no correlation between scapulothoracic muscle strength and functional activity in volleyball players

Advance in Quantitative Tests of Muscle Strength Measurement (review) / 中国康复理论与实践

As the manual muscle testing is not sensitive enough to reflect the change of muscle strength, more and more people begin to use isokinetic dynamometry and handheld dynamometer for quantitative tests of muscle strength measurement. This paper briefly introduced the history of clinical approaches of muscle strength measurement, compared the advantages and disadvantages of various quantitative mus-cle strength testing, on which the specific techniques of clinical muscle strength measurement were discussed.