Anterior deltoid muscle tension quantified with shear wave ultrasound elastography correlates with pain level after reverse shoulder arthroplasty

Optimizing Muscle-Tendon Lengths in Reverse Total Shoulder Arthroplasty: Evaluation of Surgical and Implant-Design-Related Parameters

BACKGROUND

Optimizing the function of muscles that cross the glenohumeral articulation in reverse total shoulder arthroplasty (RTSA) is controversial. The current study used a geometric model of the shoulder to systematically examine surgical placement and implant-design parameters to determine which RTSA configuration most closely reproduces native muscle-tendon lengths of the deltoid and rotator cuff.

METHODS

A geometric model of the glenohumeral joint was developed and adjusted to represent small, medium, and large shoulders. Muscle-tendon lengths were assessed for the anterior deltoid, middle deltoid, posterior deltoid, and supraspinatus from 0 to 90° of scaption; for the subscapularis from 0° to 60° of internal rotation (IR) and 0° to 60° of scaption; for the infraspinatus from 0° to 60° of external rotation (ER) and 0° to 60° of scaption; and for the teres minor from 0° to 60° of ER at 90° of scaption. RTSA designs were virtually implanted using the following parameters: (1) surgical placement with a centered or inferior glenosphere position and a humeral offset of 0, 5, or 10 mm relative to the anatomic neck plane, (2) implant design involving a glenosphere size of 30, 36, or 42 mm, glenosphere lateralization of 0, 5, or 10 mm, and humeral neck-shaft angle of 135°, 145°, or 155°. Thus, 486 RTSA-shoulder size combinations were analyzed. Linear regression assessed the strength of association between parameters and the change in each muscle-tendon length from the native length.

RESULTS

The configuration that most closely restored anatomic muscle-tendon lengths in a small shoulder was a 30-mm glenosphere with a centered position, 5 mm of glenoid lateralization, 0 mm of humeral offset, and a 135° neck-shaft angle. For a medium shoulder, the corresponding combination was 36 mm, centered, 5 mm, 0 mm, and 135°. For a large shoulder, it was 30 mm, centered, 10 mm, 0 mm, and 135°. The most important implant-design parameter associated with restoration of native muscle-tendon lengths was the neck-shaft angle, with a 135° neck-shaft angle being favored (β = 0.568 to 0.657, p < 0.001). The most important surgical parameter associated with restoration of native muscle-tendon lengths was humeral offset, with a humeral socket placed at the anatomic neck plane being favored (β = 0.441 to 0.535, p < 0.001).

CONCLUSIONS

A combination of a smaller, lateralized glenosphere, a humeral socket placed at the anatomic neck plane, and an anatomic 135° neck-shaft angle best restored native deltoid and rotator cuff muscle-tendon lengths in RTSA.

CLINICAL RELEVANCE

This study of surgical and implant factors in RTSA highlighted optimal configurations for restoration of native muscle-tendon lengths of the deltoid and rotator cuff, which has direct implications for surgical technique and implant selection. Additionally, it demonstrated the most influential surgical and implant factors with respect to muscle-tendon lengths, which can be used to aid intraoperative decision-making.

The Fate of the Shoulder Post Rotator Cuff Repair: Biomechanical Properties of the Supraspinatus Tendon and Surrounding Structures

The study aimed to describe the changes in biomechanical properties of the supraspinatus tendon, deltoid muscle, and humeral head post arthroscopic rotator cuff repair using shear wave elastography. Shear wave velocity of the tendon, deltoid, and humeral head of 48 patients was measured at predetermined sites at 1 week, 6 weeks, 12 weeks, 6 months, and 12 months post repair. One-way ANOVA with Tukey's correction and Spearman's correlation were performed. Mean±SEM healing tendon stiffness, adjacent to tendon footprint, increased from 1 week (6.2±0.2 m/s) to 6 months (7.5±0.3 m/s) and 12 months (7.8±0.3 m/s) (P<0.001). Mean±SEM deltoid muscle stiffness was higher at 12 months (4.1±0.2 m/s) compared to 1 week (3.4±0.1 m/s) and 12 weeks (3.5±0.1 m/s) (P<0.05). Humeral head stiffness did not change. Following arthroscopic rotator cuff repair, supraspinatus tendon stiffness increased in a curvilinear fashion over 6 months. From 6 months, deltoid muscle stiffness increased, corresponding to when patients were instructed to return to normal activities.

The application of ultrasound shear wave elastography in the prediction of paradoxical upgrading reaction in tuberculous lymphadenitis. a pilot study

BACKGROUND

Paradoxical upgrading reaction (PUR) indicates the unanticipated deterioration during therapy in patients with tuberculous lymphadenitis. We investigated the diagnostic performance of the ultrasonography and shear wave elastography (SWE) in predicting the therapeutic response of peripheral tuberculous lymphadenitis.

METHODS

A prospective observational study was conducted from December 2017 to August 2020. Participants diagnosed with peripheral tuberculous lymphadenitis were included for a longitudinal follow-up utilizing ultrasonography with two-dimensional SWE to record sonographic features and the maximum elasticity value (Emax). We defined PUR as the development of any worsening symptoms of the pre-existing lymphadenitis within one month after the previous ultrasonography.

RESULTS

A total of 108 sonographic and SWE examinations were performed in 20 enrollees (75% woman), and their mean ( ± standard deviation) age was 49.6 ( ± 22.7) years. The area under the receiver operating characteristic curve of Emax to predict the next-month PUR was 0.906 at the cut-point of 85 kPa, with an accuracy of 87.0%, a sensitivity of 81.1% and a specificity of 87.9%. Multivariate analysis indicated that Emax > 85 kPa (OR: 24.85, 95% CI: 4.01-154.08, p < 0.001), Emax increment rate >2 kPa/month (OR: 15.14, 95% CI: 4.24-54.06, p < 0.001), and heterogeneous echogenicity (OR: 4.37, 95% CI: 1.16-16.43, p = 0.029) were independent sonographic predictors for PUR in the coming month.

CONCLUSIONS

A high and non-declining Emax level and heterogeneous echogenicity were associated with the next-month PUR of tuberculous lymphadenitis. Ultrasonography with SWE may be a potential radiologic marker to predict the therapeutic response of tuberculous lymphadenitis.