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.

Relationship between rotator cuff muscle function and shoulder abduction function in patients with posterior superior rotator cuff tear: a dynamic biomechanical study / 中华创伤杂志

Objective:To evaluate the relationship of rotator cuff muscle function with shoulder abduction function after posterior superior rotator cuff tear via dynamic biomechanical study.Methods:By using the customized dynamic shoulder biomechanical testing system, seven freshly frozen cadaveric shoulders were used to stimulate shoulder abduction at 90° under four statuses: (1) intact rotator cuff with activation (normal rotator cuff group); (2) posterior superior rotator cuff tear with activation (posterior superior rotator cuff tear with activation group); (3) posterior superior rotator cuff tear with posterior superior rotator cuff deactivation (posterior superior rotator cuff tear with deactivation group); (4) none rotator cuff tissue above the geometric rotation center of the humeral head with deactivation (global tear group). The peak and stable value of middle deltoid force were used to evaluate biomechanical status in different rotator cuff tear conditions during shoulder abduction procedure. The peak subacromial pressure, average subacromial pressure, subacromial contact area, and subacromial force were used to evaluate subacromial pressed conditions under different rotator cuff tear conditions. The peak and stable ratio of glenohumeral contact force/middle deltoid force were used to evaluate shoulder stability under different rotator cuff tear conditions.Results:During dynamic abduction at 90°, the peak and stable value of middle deltoid force were (42.1±8.7)N and (29.9±7.4)N in normal rotator cuff group, (45.7±10.3)N and (30.5±7.2)N in posterior superior rotator cuff tear with activation group, and (48.4±13.4)N and (29.9±4.8)N in posterior superior rotator cuff tear with deactivation group (all P>0.05). But the peak and stable value of middle deltoid force were (69.7±9.7)N and (53.7±8.9)N in global tear group, significantly increased compared with other three groups (all P<0.05). The elevated middle deltoid force increased the subacromial contact pressure between glenohumeral head and acromion. The peak subacromial pressure, average subacromial pressure, subacromial contact area, and subacromial force were (0.40±0.05)MPa, (0.22±0.03)MPa, (7.71±5.09)mm 2, and (1.66±1.06)N respectively in normal rotator cuff group, (0.41±0.05)MPa, (0.26±0.07)MPa, (12.71±11.35)mm 2, and (2.93±2.46)N respectively in posterior superior rotator cuff tear with activation group, and (0.50±0.12)MPa, (0.26±0.07)MPa, (17.29±9.11)mm 2, and (4.09±1.46)N respectively in posterior superior rotator cuff tear with deactivation group (all P>0.05). However, the peak subacromial pressure, average subacromial pressure, subacromial contact area, and subacromial force were (3.64±1.70)MPa, (0.98±0.49)MPa, (47.63±11.91)mm 2, and (45.48±23.86)N respectively in global tear group, significantly higher than those in other three groups (all P<0.05). The peak and stable ratio of glenohumeral contact force/middle deltoid force were 2.24±0.30 and 2.46±0.13 in normal rotator cuff group, 2.21±0.19 and 2.52±0.08 in posterior superior rotator cuff tear with activation group, and 2.03±0.14 and 2.42±0.16 in posterior superior rotator cuff tear with deactivation group (all P>0.05). However, the peak and stable ratio of glenohumeral contact force/middle deltoid force were 1.40±0.14 and 1.52±0.41 in global tear group, significantly higher than those in other three groups (all P<0.05). No significant differences of the above parameters were observed in posterior superior rotator cuff tear with activation group, posterior superior rotator cuff tear with deactivation group and global tear group (all P>0.05). Conclusions:After posterior superior rotator cuff tear, rotator cuff muscle function does not affect the whole abduction function of shoulder. When the size of rotator cuff tear involves the whole superior humeral head rotation center, the normal abduction function of shoulder will be significantly impaired.

The feasibility and preliminary application of deltoid muscle volume measurement using MR volume of interest method / 中华放射学杂志

Objective To explore the feasibility and repeatability of deltoid muscle volume measurement using MR volume of interest method, and discuss the clinical significance. Methods Seventy-eight subjects'' MR images were retrospectively reviewed including 33 normal shoulders, 22 rotator cuff tear (7 male, 15 female), 12 cases with labrum lesions (11 male, 1 female), and 2 long head of biceps tendon lesions. Routine axial 2D MR images of deltoid muscle were transported into post-processing work station, the matrix of all images were higher than 275 × 336, and the imaging field included the upper and lower margin of the deltoid muscle, and the three dimension shape of muscle was reconstructed by software based on MR volume of interest, then the muscle volume was calculated automatically. This process was independently performed by 2 operators, and operator 1 repeated this process 1 week later. Intra-class correlation coefficient and 95％confidence interval were used to analyze the reliability and repeatability of the measurement. Deltoid muscle volumes of different ages and different pathological processes were compared using stratified sampling method, one-way analysis of variance (ANOVA), least significant difference (LSD) multiple comparison method, and independent-samples t test. Results Three-dimensional shape of deltoid muscle were well demonstrated and corresponded well to the known anatomy. The measurement showed very good inter-and intra-observer consistency (ICC: 0.983 and 0.995, respectively). There were statistical differences in deltoid muscle volume between group A and C [volume:(382.39 ± 38.87) cm3 and (279.15 ± 63.65) cm3;P=0.000], group B and C [volume:(358.49 ± 44.50) cm3 and (279.15 ± 63.65) cm3; P=0.000]. The normal participants were divided by gender into normal group 1 (9 males and 15 females) and normal group 2 (13 males and 1 female) using stratified random sampling method. The deltoid muscle volume of patients with rotator cuff tear was lower than the normal group 1 [volume:(313.21±63.48) cm3 versus (359.08±57.98) cm3;t=-2.562, P<0.05], and there was no statistical difference in deltoid muscle volume between labrum-ligament complex lesions patients and the normal group 2 [volume: (394.28 ± 33.67) cm3 versus (389.30 ± 22.14) cm3; t=0.385, P=0.704]. Conclusions Volume of interest measurement based on routine MR images could evaluate the deltoid muscle volume conveniently and directly, and which could be used as a preferred choice for muscle volume evaluation.

Deltoid-splitting approach and deltopectoral approach in the repair of proximal humeral fracture:a meta-analysis / 中国组织工程研究

BACKGROUND:Numerous studies confirmed that compared with deltopectoral approach, deltoid-splitting approach for proximal humeral fractures has good therapeutic effects, but precise superiority remains poorly understood. OBJECTIVE:To compare the therapeutic effects of deltopectoral approach and smal incision deltoid-splitting approach in the repair of proximal humeral fractures using meta-analysis. METHODS:We retrieved MEDLINE, Embase, the Cochrane library, Wanfang Database and PubMed by computer for articles on control ed trials of deltopectoral approach and smal incision deltoid-splitting approach in the repair of proximal humeral fractures published from 2010 to 2014. Neer score, operation time, intraoperative blood loss, incision length, length of hospital stay, Visual Analogue Scale score, fracture healing time, and Constant score were used as evaluation indexes of Meta analysis. RevMan 5.2 software was used for analysis. RESULTS AND CONCLUSION:Eventual y nine articles were included, total y 721 patients, published from 2010 to 2014 years. There were eight in Chinese, and one in English. Meta-analysis results showed that compared with deltopectoral approach, deltoid-splitting approach in the treatment of proximal humeral fractures could shorten operation time, reduce intraoperative blood loss, shorten length of incision, elevate Neer score and Constant score (P<0.05). No significant difference in fracture healing time, hospitalization days, and Visual Analogue Scale score was detected between the two methods of surgical approach. These data indicated that compared with deltopectoral approach, deltoid-splitting approach in the repair of proximal humeral fracture has certain superiority. Deltoid-splitting approach can be firstly selected in the permit of hospital conditions.

Estudo da origem acromial do músculo deltoide / The anatomy of the acromial deltoid muscle origin

As características macroscópicas da origem do músculo deltoide foram estudadas em 12 ombros de cadáveres. A origem acromial anterior e lateral do deltoide foi dissecada e analisada macroscopicamente com auxílio de computação gráfica. Determinamos as medidas dos diâmetros ântero-posterior do acrômio e do deltoide e suas respectivas áreas e, a seguir, realizamos simulações por computação de descompressões subacromiais de 4, 6 e 8 mm. As descompressões subacromiais simuladas de 8 mm, 6 mm e 4 mm desinserem 34,7%, 32 % e 29,1% da área de origem do deltoide, respectivamente. Concluímos que os diâmetros ântero-posteriores e as áreas do acrômio e deltoide possuem diferenças estatísticas significantes. Os diâmetros lateromediais do acrômio em relação ao deltoide não apresentam diferenças estatísticas, assim como a área do deltoide remanescente após uma descompressão subacromial de 4 mm, quando comparada com a área do acrômio.

Dislocation of the shoulder caused by fibrous deltoid muscle after intramuscular injection antibiotic(s) in children

Dislocation of the shoulder after intramuscular injection antibiotic(s) is rare and this conditon was limit described in literature. Our purposes were: (1) determining the clinical symptoms, X-ray and CT findings; and (2) determining the indications and the surgical technique and evaluation of the surgical result. Material and methods: 62 children (29 females, 33 males) aged from 4 to 16 years were included. Clinical and X- ray findings were analysed for anterosuperior subluxation or dislocation of humeral head. The patients were operated to release of origin or insretion of the mild Deltoid muscle or Z plasty of this one. Surgical procedures provided good result in 75.3 percent, fair in 24.7 percent and there were no infection or neuromuscular complication in these cases. Conclusions: This condition always resulted from repeated Deltoid intramuscular injection. The surgical treatment with resection of fibrous portions constantly gives relief of symptoms and provides good function.

Microanatomy and histological study of the fascicular group to deltoid muscle in axillary nerve at the level of quadrilateral zone / 中华创伤骨科杂志

Objective To observe and study the distribution and histological feature of the fascicular groups to deltoid muscle in axillary nerve at the level of quadrilateral zone. Methods 12 adult human cadavers (24 upper limbs)embalmed by formalin were used,, and microsurgical longitudinal contradissection of the axillary nerves by tracing their terminal branches were processed. At the level of quadrilateral zone,distrabution of the fscicular groups to deltoid muscle in the never trunk were recorded and their diameters were measured;Another 6 upper extremities (3 right and 3 left) of fresh-frozen human cadavers were obtained.Axillary nerves and their fascicular groups were exposured, and the segments at the level of qusdrilateral zone gotten, then histological cross section was done, acetycholinesterase (ACHE) stained with the method of Karnovsky Roots and myelin stained with the method of Loyezs. Defferent never fibres were distinguished under microscope and the fiber number was counted with IAS . Results At the level of quadrilateral zone,fasciculars were divided into two groups.The fascicular group of anterior branch to deltoid muscle was in the lateral of the nerve trunk . Its cross sectional area was (2.449?1.327)mm2 ,occupied 55.4%?9.3%of the axillary nerve trunk ;Its most fibers were motor fibers;The number of fibers is (2112?631), occupied 45.6 %?1.1%of all fibers of axillary nerve . Conclusions In the treatment of root avulsion of brachial plexus injury, selective suture donor nerve with the lateral fascicular group should be processed to repair the function of shoulder abduction,fibers loss would be reduced and rate of functional restoration improved .

STUDY ON COMPARTMENTALIZATION, DIS-TRIBUTION AND CROSS-SECTIONAL AREAS OF FIBER TYPES IN HUMAN DELTOID MUSCLE / 解剖学报

The deltoid muscles on both sides of 8 male cadavers were studied within 24 hours after death. According to its fiber architecture, origins and insertions, and nerve distribution, the deltoid muscle was divided into three compartments: an anterior, a middle and a posterior. The muscle samples were taken respectively from the superficial and the deep portion of each compartment of the deltoid muscle. Frozen transverse sections were stained fer myosin ATPase. Muscle fibers were identified as type Ⅰ and type Ⅱ. The proportion of fiber types in each portion was calculated on microscopic photographs and mean cross-sectional areas of both fiber types were measured by imaging analytical system. The results showed that the proportion of type Ⅰ fiber in the superficial and deep portion of the middle compartment is significantly higher than that of the corresponding portion of the anterior and posterior compartments, and the proportion in the deep portion of each compartment is higher than that of the superficial one, however no difference was found between the left and right sides. The fiber size among all portions is not obviously different, but the diameter of type Ⅱ fiber in the deep portion of the middle compartment is significantly smaller than that of other portions. Except the deep portion of the middle compartment, the diameter of both fiber types of the right muscle is larger than those of the left one, although statistical analysis showed that the difference is not significant. The authors suggest that the difference of fiber type distribution within the deltoid muscle is closely related with the functional differentiation of the muscle and the characteristic higher typeⅠ fiber proportion and smaller type Ⅱ fiber diamiter in the deep portion of the middle compartment probably indicate that the main function of this portion is to keep the shoulder joint stability.