Are the shoulder joint function, stability, and mobility tests predictive of handstand execution?

Handstand is a basic element common across gymnastic disciplines and physical education classes that is frequently evaluated for quality in competition or skill acquisition. The correct handstand execution relies on maintaining balance, for which the shoulders seem particularly important. This study explores the relationship between shoulder joint function and the quality of handstand execution in novice college athletes (n = 111; aged 19-23 years). We assessed the shoulder joint function using standardized field tests (Upper Quarter Y Balance Test and Closed Kinetic Chain Upper Extremity Stability Test) and evaluated handstand execution on official rating scale. Ordinal logistic regression models showed no relationship between the quality of handstand execution (E-score) and measures of shoulder joint stability or mobility in our sample (POR = 0.97 [0.91, 1.03] and 1.00 [0.91, 1.09] for E-score). Two major factors may have caused an observed pattern of results. Firstly, the standardized tests assess shoulder joints in different loads and ranges of motion compared to handstands. Secondly, our novice sample was not able to perform the handstand sufficiently well. In our sample of novice college athletes, shoulder function seems not related to handstand execution as other latent factors hindered their performance.

Deep squat test - Functional movement Screen: Convergent validity and ability to discriminate subjects with different levels of joint mobility.

BACKGROUND: Functional Movement Screen (FMS) is an important tool in the assessment of exercise practice. Assuming FMS lacks precise validity for assessing postural deficits, further research is needed to assess whether it is a sufficiently precise tool for analysing joint mobility. Research aims were to evaluate: convergent validity of Deep Squat (DS) - one of FMS tests - regarding joint mobility, using data from a three-dimensional motion analysis as a comparable method; DS's ability to discriminate between subjects with different joint mobility levels. METHODS: Sixty subjects were selected (23.6 ± 3.8 years). DS was performed according to FMS guidelines. Subjects' performance in frontal and sagittal planes was recorded by two video cameras and subsequently scored by two FMS-certified evaluators. Three-dimensional motion analyses of DS were acquired by a Vicon Motion Capture System (200 Hz). Ten trials were acquired for each subject. Ankle, knee, hip, and shoulder angular positions in sagittal plane were determined from the FullBody PlugInGait model. Spearman's coefficient examined the correlation between angular positions and DS score. Kruskal-Wallis test was used to assess the DS ability to discriminate between subjects with different joint mobility levels by comparing different scores. RESULTS: Negligible to moderate correlations were found between DS score and angular positions (-0.5 < r < 0.5). Only shoulder angular positions showed differences between score "1" and "2" (p < 0.05). Shoulder and hip angular positions showed no differences between score "2" and "3" (p < 0.05). CONCLUSIONS: DS yielded low convergent validity regarding joint mobility and did not show the ability to discriminate between subjects with different joint mobility levels.

Effectiveness of a joint mobilizations protocol for shoulder subacromial pain syndrome: A pilot study.

BACKGROUND: Subacromial pain syndrome (SPS) is the most frequent shoulder pathology. The aims of this prospective randomized study were to evaluate the effects of some specific shoulder joint mobilizations ("spin correction"), and the effectiveness of a rehabilitation program, named Shoulder Global Concept, in SPS patients. METHODS: 45 patients with SPS were randomly assigned to two groups, to benefit from a different first session of mobilizations: the experimental group received all specific mobilizations, while the control group received the same program but without the spin correction mobilizations. The second session was identical for both groups, with all specific mobilizations. Before and after the first two sessions, range of motion (ROM) in flexion, abduction, external and internal rotations, pain and functional status with Constant score and Quick Dash were evaluated. Evaluation was repeated with 24 patients after 11 rehabilitation sessions. Rehabilitation with Shoulder Global Concept included 13 mobilizations aiming at improving the ROM with passive and active-assisted mobilizations, static stretching, and muscle strengthening. RESULTS: All ROM were improved at the end of the first session for both groups, but significantly more in the experimental group for glenohumeral (GH) abduction and external rotation (p < 0.05). Functional scores, pain and strength were significantly improved after 11 rehabilitation sessions with the Shoulder Global Concept. CONCLUSION: This manual therapy method was able to improve shoulder mobility in one session. The additional joint mobilizations (spin correction) specifically increased GH abduction and external rotation. Rehabilitation of SPS with Shoulder Global Concept allowed to improve functional capacity and decrease pain.

Estimation of Shoulder Joint Rotation Angle Using Tablet Device and Pose Estimation Artificial Intelligence Model.

Traditionally, angle measurements have been performed using a goniometer, but the complex motion of shoulder movement has made these measurements intricate. The angle of rotation of the shoulder is particularly difficult to measure from an upright position because of the complicated base and moving axes. In this study, we attempted to estimate the shoulder joint internal/external rotation angle using the combination of pose estimation artificial intelligence (AI) and a machine learning model. Videos of the right shoulder of 10 healthy volunteers (10 males, mean age 37.7 years, mean height 168.3 cm, mean weight 72.7 kg, mean BMI 25.6) were recorded and processed into 10,608 images. Parameters were created using the coordinates measured from the posture estimation AI, and these were used to train the machine learning model. The measured values from the smartphone's angle device were used as the true values to create a machine learning model. When measuring the parameters at each angle, we compared the performance of the machine learning model using both linear regression and Light GBM. When the pose estimation AI was trained using linear regression, a correlation coefficient of 0.971 was achieved, with a mean absolute error (MAE) of 5.778. When trained with Light GBM, the correlation coefficient was 0.999 and the MAE was 0.945. This method enables the estimation of internal and external rotation angles from a direct-facing position. This approach is considered to be valuable for analyzing motor movements during sports and rehabilitation.

Factors influencing shoulder stiffness after open reduction and internal fixation of proximal humeral fractures.

OBJECTIVES: The study aimed to investigate the factors associated with shoulder stiffness following open reduction and internal fixation (ORIF) of proximal humeral fractures. PATIENTS AND METHODS: The retrospective study included a total of 151 patients who underwent ORIF of proximal humeral fractures between January 2016 and May 2021. Based on their shoulder joint motion at the latest follow-up, the patients were divided into two groups. The stiffness group (n=32; 8 males, 24 females; mean age: 62.4±9.3 years; range, 31 to 79 years), exhibited restricted shoulder forward flexion (<120°), limited arm lateral external rotation (<30°), and reduced back internal rotation below the L3 level. The remaining patients were included in the non-stiffness group (n=119; 52 males, 67 females; mean age: 56.4±13.4 years; range, 18 to 90 years). Various factors were examined to evaluate the association with shoulder stiffness following ORIF of proximal humeral fractures by multivariate unconditional logistic regression models. RESULTS: The mean follow-up duration was 31.8±12.6 (range, 12 to 68) months. Based on the results of the multivariate regression analysis, it was found that high-energy injuries [compared to low-energy injuries; adjusted odds ratio (aOR)=7.706, 95% confidence interval (CI): 3.564-15.579, p<0.001], a time from injury to surgery longer than one week (compared to a time from injury to surgery equal to or less than one week; aOR=5.275, 95% CI: 1.7321-9.472, p=0.031), and a body mass index (BMI) >24.0 kg/m2 (compared to a BMI between 18.5 and 24.0 kg/m2 ; aOR=4.427, 95% CI: 1.671-11.722, p=0.023) were identified as risk factors for shoulder stiffness following ORIF of proximal humeral fractures. CONCLUSION: High-energy injury, time from injury to surgery longer than one week, and BMI >24.0 kg/m2 were identified as independent risk factors for shoulder stiffness after proximal humeral fracture surgery, which should be treated with caution in clinical treatment.

Efficacy of supervised self-reduction vs. physician-assisted techniques for anterior shoulder dislocations: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: Reduction manipulation using self-reduction procedures such as Stimson, Milch, and Boss-Holtzach should be easy and effective and also require less force, pain medication, and outside assistance. This technique should not cause damage to arteries, nerves, or shoulder joint components. Self-reduction is straightforward and can be done in clinics, making it ideal for people who suffer from shoulder joint dislocation frequently. The goal of this study is to compare the effectiveness of supervised self-reduction procedures vs. physician-assisted treatments in the treatment of anterior shoulder dislocations. METHOD: We conducted a comprehensive search on PubMed, Scopus, Web of Science, and Cochrane up to March 22, 2023, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist. Relevant articles were reviewed, with a focus on studies comparing supervised self-reduction techniques to physician-assisted techniques in cases of anterior shoulder dislocation. RESULTS: Four papers in all were included in the meta-analysis. One prospective trial, one case-control study, one randomized clinical trial, and one retrospective trial made up these studies. The studies involved 283 patients in the physician-assisted group and 180 patients in the supervised self-reduction group. They were carried out in four European countries: Italy, Germany, Portugal, and Spain. The success rate of supervised self-reduction techniques was significantly higher, with an odds ratio of 2.71 (95% CI 1.25-5.58, p-value = 0.01). Based on the Visual Analog Scale (VAS) score, the physician-assisted group reported significantly higher maximum pain, with a mean difference of 1.98 (95% CI 1.24-2.72, p-value < 0.01). The self-reduction approaches exhibit shorter reduction time in comparison to physician-assisted groups. In addition, the self-reduction groups do not document any complications. Based on the GRADE system, the level of assurance in the evidence was high. CONCLUSION: Supervised self-reduction techniques outperform in terms of success rate and reduction-related maximum pain. These techniques could be used as an effective first-line treatment for anterior shoulder dislocation, potentially reducing the need for analgesics and emergency room visits.

Metaverse, virtual reality and augmented reality in total shoulder arthroplasty: a systematic review.

PURPOSE: This systematic review aims to provide an overview of the current knowledge on the role of the metaverse, augmented reality, and virtual reality in reverse shoulder arthroplasty. METHODS: A systematic review was performed using the PRISMA guidelines. A comprehensive review of the applications of the metaverse, augmented reality, and virtual reality in in-vivo intraoperative navigation, in the training of orthopedic residents, and in the latest innovations proposed in ex-vivo studies was conducted. RESULTS: A total of 22 articles were included in the review. Data on navigated shoulder arthroplasty was extracted from 14 articles: seven hundred ninety-three patients treated with intraoperative navigated rTSA or aTSA were included. Also, three randomized control trials (RCTs) reported outcomes on a total of fifty-three orthopedics surgical residents and doctors receiving VR-based training for rTSA, which were also included in the review. Three studies reporting the latest VR and AR-based rTSA applications and two proof of concept studies were also included in the review. CONCLUSIONS: The metaverse, augmented reality, and virtual reality present immense potential for the future of orthopedic surgery. As these technologies advance, it is crucial to conduct additional research, foster development, and seamlessly integrate them into surgical education to fully harness their capabilities and transform the field. This evolution promises enhanced accuracy, expanded training opportunities, and improved surgical planning capabilities.

Biomechanical study of 3D-printed titanium alloy pad for repairing glenoid bone defect.

Background: The purpose of this study was to investigate the effect of 3D-printed technology to repair glenoid bone defect on shoulder joint stability. Methods: The shoulder joints of 25 male cadavers were tested. The 3D-printed glenoid pad was designed and fabricated. The specimens were divided into 5 groups. Group A: no bone defect and the structure of the glenoid labrum and joint capsule was intact; Group B: Anterior inferior bone defect of the shoulder glenoid; Group C: a pad with a width of 2 mm was installed; Group D: a pad with a width of 4 mm was installed; Group E: a pad with a width of 6 mm was installed. This study measured the distance the humeral head moved forward at the time of glenohumeral dislocation and the maximum load required to dislocate the shoulder. Results: The shoulder joint stability and humerus displacement was significantly lower in groups B and C compared with group A (p < .05). Compared with group A, the stability of the shoulder joint of group D was significantly improved (p < .05). However, there was no significant difference in humerus displacement between groups D and A (p > .05). In addition, compared with group A, shoulder joint stability was significantly increased and humerus displacement was significantly decreased in group E (p < .05). Conclusion: The 3D-printed technology can be used to make the shoulder glenoid pad to perfectly restore the geometric shape of the shoulder glenoid articular surface. Moreover, the 3D-printed pad is 2 mm larger than the normal glenoid width to restore the initial stability of the shoulder joint.

Critical Shoulder Angle in Patients With Cuff Tears.

OBJECTIVE: The pathogenesis of rotator cuff tears (RCTs) is multifactorial. Critical shoulder angle (CSA), which represents the lateral extension of the acromion over the cuff, has been proposed as an extrinsic risk factor. The aim of the present systematic review and meta-analysis was to analyze the available literature regarding the correlation between RCT and CSA. METHODS: A review was carried out in accordance with the "Preferred Reporting Items for Systematic reviews and Meta-Analyses" guidelines on July 17, 2023, using the following databases: PubMed, Ovid, and Cochrane Reviews. The following keywords were used: "critical shoulder angle," "rotator cuff tears," and "rotator cuff lesions." The methodological quality of the studies was assessed with the MINORS SCORE. RESULTS: Twenty-eight studies were included. The average CSA among the 2110 patients with full-thickness RCT was 36.7 degrees, whereas the same value among the 2972 controls was 33.1 degrees. The average CSA in the 348 patients with partial-thickness RCT was 34.6 degrees, whereas it was 38.1 degrees in the 132 patients with massive RCT. The average MINORS score was 15.6. CONCLUSIONS: CSA values were significantly higher in patients with RCT compared with the asymptomatic population. In addition, it appears that CSA values increase with the severity of rotator cuff involvement.

Subscapularis Management in Anatomic Total Shoulder Arthroplasty A Review.

Surgical management of the subscapularis tendon is critical to a successful outcome following anatomic total shoulder arthroplasty. However, the optimal surgical technique for adequate exposure of the glenohumeral joint while mini-mizing complications resulting from subscapularis tendon dysfunction continues to be controversial. Common surgical techniques for the management of the subscapularis tendon include tenotomy, peeling, sparing, and lesser tuberosity oste-otomy. Despite a number of published studies comparing these techniques, no consensus has been reached regarding optimal management. This article reviews the extensive literature on the biomechanical, radiologic, and clinical outcomes of each technique, including recently published comparison studies.

Biomechanical Characteristics of Glenosphere Orientation Based on Tilting Angle and Overhang Changes in Reverse Shoulder Arthroplasty.

Background: Glenoid position and inclination are important factors in protecting against scapular notching, which is the most common complication that directly affects the longevity of reverse shoulder arthroplasty (RSA). This study aimed to investigate the biomechanical characteristics of glenosphere orientation, comparing neutral tilt, inferior overhang with an eccentric glenosphere at the same placement of baseplate, and inferior tilt after 10° inferior reaming in the lower part of the glenoid in RSA. Methods: Nine cadaveric shoulders were tested with 5 combinations of customized glenoid components: a centric glenosphere was combined with a standard baseplate (group A); an eccentric glenosphere to provide 4-mm inferior overhang than the centric glenosphere was combined with a standard baseplate (group B); a centric glenosphere was combined with a wedge-shaped baseplate tilted inferiorly by 10° with the same center of rotation (group C); an eccentric glenosphere was attached to a wedge-shaped baseplate (group D); and 10° inferior reaming was performed on the lower part of the glenoid to apply 10° inferior tilt, with a centric glenosphere secured to the standard baseplate for simulation of clinical tilt (group E). Impingement-free angles for adduction, abduction, forward flexion, external rotation, and internal rotation were measured. The capability of the deltoid moment arm for abduction and forward flexion, deltoid length, and geometric analysis for adduction engagement were evaluated. Results: Compared with neutral tilt, inferior tilt at the same position showed no significant difference in impingement-free angle, moment arm capability, and deltoid length. However, group D resulted in better biomechanical properties than a central position, regardless of inferior tilt. Group E demonstrated a greater range of adduction, internal and external rotation, and higher abduction and forward flexion capability with distalization, compared to corresponding parameters for inferior tilt with a customized wedge-shaped baseplate. Conclusions: A 10° inferior tilt of the glenosphere, without changing the position of the baseplate, had no benefit in terms of the impingement-free angle and deltoid moment arm. However, an eccentric glenosphere had a significant advantage, regardless of inferior tilt. Inferior tilt through 10° inferior reaming showed better biomechanical results than neutral tilt due to the distalization effect.

Complications and Reinterventions of Reverse Total Shoulder Arthroplasty in a Korean Population: 14-Year Experience in Reverse Shoulder Arthroplasty.

Background: There are few reports on the revision or reintervention of reverse total shoulder arthroplasty (RTSA) in South Korea. The purpose of this study was to evaluate the true incidence of complications and reintervention of RTSA and clinical and radiological outcomes based on our 14-year experience in RTSA in a Korean population. Methods: Between March 2008 and June 2022, 412 consecutive cases of RTSA were performed in 388 patients with an average age of 74.4 years at our institute. Excluding 23 patients lost to follow-up, 365 patients (373 shoulders including 8 bilateral cases) who underwent primary RTSA with more than 6 months of follow-up were enrolled in this study. We evaluated those who had complications or reintervention including revision RTSA for failed RTSA. Patient charts were reviewed, and clinical outcomes including clinical scores, complications, and reintervention and radiologic outcomes were evaluated at the last follow-up. Results: Among the 373 shoulders that underwent primary RTSA, complications were found in 50 patients (13.94%, 10 men and 40 women with a mean age of 75.9 ± 6.7 years [range, 51-87 years]). The causes of complications were as follows: 13 acromion, coracoid, or scapular spine fractures, 10 loosening (glenoid: 5, humeral stem: 5), 5 infections, 4 periprosthetic fractures, 2 instability, 2 neurologic complications, and 14 miscellaneous complications. Twenty patients (5.63%, 4 men and 16 women with a mean age of 74.2 ± 8.2 years [range, 51-87 years]) underwent reintervention. The interval to the first reintervention was 27.8 ± 23.1 months (range, 0.1-78 months). The causes of reintervention (20 cases) were 8 loosening (glenoid: 4, humeral stem: 4), 5 infections, 5 fractures, and 2 instability. Among them, 15 component revisions (4.02%) were performed. At the last follow-up, American Shoulder and Elbow Surgeons, University of California at Los Angeles, and Simple Shoulder Test scores were improved from 25.4, 12.4, and 1.6 preoperatively to 40.4, 16.2, and 3.2, respectively. Forward flexion (48° to 87°), abduction (52° to 79°), external rotation (18° to 22°), and internal rotation (buttock to L2) were improved. Conclusions: After primary RTSA in a Korean population, the complication, reintervention, and revision rates were 13.94%, 5.63%, and 4.02%, respectively. Careful evaluation of the complications and adequate treatments should be performed.

Management of Bone Loss in Posterior Glenohumeral Shoulder Instability: Current Concepts.

¼ Posterior glenohumeral instability is relatively uncommon compared with anterior instability, but is becoming an increasingly recognized and surgically managed shoulder pathology.¼ Soft-tissue stabilization alone may not be sufficient in patients who present with substantial bone loss to the posterior glenoid and/or the anterior humeral head.¼ For posterior glenoid defects, posterior glenoid osteoarticular augmentation can be used, and posterior glenoid opening wedge osteotomy can be considered in cases of posterior instability with pathologic retroversion.¼ For humeral head lesions, several surgical treatment options are available including subscapularis transposition into the humeral head defect, autograft or allograft reconstruction, humeral rotation osteotomy, and shoulder arthroplasty.

Reverse total shoulder replacement versus anatomical total shoulder replacement for osteoarthritis: population based cohort study using data from the National Joint Registry and Hospital Episode Statistics for England.

OBJECTIVES: To answer a national research priority by comparing the risk-benefit and costs associated with reverse total shoulder replacement (RTSR) and anatomical total shoulder replacement (TSR) in patients having elective primary shoulder replacement for osteoarthritis. DESIGN: Population based cohort study using data from the National Joint Registry and Hospital Episode Statistics for England. SETTING: Public hospitals and publicly funded procedures at private hospitals in England, 2012-20. PARTICIPANTS: Adults aged 60 years or older who underwent RTSR or TSR for osteoarthritis with intact rotator cuff tendons. Patients were identified from the National Joint Registry and linked to NHS Hospital Episode Statistics and civil registration mortality data. Propensity score matching and inverse probability of treatment weighting were used to balance the study groups. MAIN OUTCOME MEASURES: The main outcome measure was revision surgery. Secondary outcome measures included serious adverse events within 90 days, reoperations within 12 months, prolonged hospital stay (more than three nights), change in Oxford Shoulder Score (preoperative to six month postoperative), and lifetime costs to the healthcare service. RESULTS: The propensity score matched population comprised 7124 RTSR or TSR procedures (126 were revised), and the inverse probability of treatment weighted population comprised 12 968 procedures (294 were revised) with a maximum follow-up of 8.75 years. RTSR had a reduced hazard ratio of revision in the first three years (hazard ratio local minimum 0.33, 95% confidence interval 0.18 to 0.59) with no clinically important difference in revision-free restricted mean survival time, and a reduced relative risk of reoperations at 12 months (odds ratio 0.45, 95% confidence interval 0.25 to 0.83) with an absolute risk difference of -0.51% (95% confidence interval -0.89 to -0.13). Serious adverse events and prolonged hospital stay risks, change in Oxford Shoulder Score, and modelled mean lifetime costs were similar. Outcomes remained consistent after weighting. CONCLUSIONS: This study's findings provide reassurance that RTSR is an acceptable alternative to TSR for patients aged 60 years or older with osteoarthritis and intact rotator cuff tendons. Despite a significant difference in the risk profiles of revision surgery over time, no statistically significant and clinically important differences between RTSR and TSR were found in terms of long term revision surgery, serious adverse events, reoperations, prolonged hospital stay, or lifetime healthcare costs.

Shoulder viscoelasticity in a raptor-inspired model alleviates instability and enhances passive gust rejection.

Recent experiments with gliding raptors reveal a perplexing dichotomy: remarkably resilient gust rejection, but, at the same time, an exceptionally high degree of longitudinal instability. To resolve this incompatibility, a multiple degree of freedom model is developed with minimal requisite complexity to examine the hypothesis that the bird shoulder joint may embed essential stabilizing and preflexive mechanisms for rejecting rapid perturbations while simplifying and reducing control effort. Thus, the formulation herein is centrally premised upon distinct wing pitch and body pitch angles coupled via a Kelvin-Voigt viscoelastic shoulder joint. The model accurately exhibits empirical gust response of an unstable gliding raptor, generates biologically plausible equilibrium configurations, and the viscoelastic shoulder coupling is shown to drastically alleviate the high degree of instability predicted by conventional linear flight dynamics models. In fact, stability analysis of the model predicts a critical system timescale (the time to double amplitude of a pitch divergence mode) that is commensurate within vivomeasured latency of barn owls (Tyto alba). Active gust mitigation is studied by presupposing the owl behaves as an optimal controller. The system is under-actuated and the feedback control law is resolved in the controllable subspace using a Kalman decomposition. Importantly, control-theoretic analysis precisely identifies what discrete gust frequencies may be rapidly and passively rejected versus disturbances requiring feedback control intervention.

Outcomes of a cementless onlay short stem reverse shoulder arthroplasty in elderly patients: a comprehensive analysis of clinical and radiological findings.

OBJECTIVE: The objective of this study was to evaluate clinical and radiological outcomes of a short stem reverse shoulder prosthesis with metaphyseal fixation specifically in older patients. METHODS: All patients, older than 70 years, submitted to a Reverse Shoulder Arthroplasty (RSA) using a cementless onlay short stem (Aequalis Ascend™ Flex Convertible Shoulder System (Stryker®)) from January 2017 to December 2021, with a minimum follow-up of 2 years, were included. Postoperative radiographs were assessed for stem loosening, subsidence, and varus-valgus tilt. Range of motion, visual analogue scale for pain, constant score, complication rate and revision rate were also analysed. RESULTS: A total of 34 patients with a mean age of 75 years (range 71-83 years) were submitted to a cementless onlay short stem RSA with a Bone Increased Off-Set (BIO-RSA) construct. The mean follow-up period was 61 months (range 54-87). Significant improvements (p < 0.001) were observed for the constant score and range of motion from the preoperative state to final follow-up. One case exhibited a significant varus deviation (> 5˚) during the follow-up period. No case of stem loosening was identified. There was only one case of complication because of post-traumatic dislocation, but the stem didn't need revision. CONCLUSION: Short stem RSA, even in patients older than 70 years, can yield a stable fixation with a good clinical and radiological outcome at short-medium term follow-up. LEVEL OF EVIDENCE: Level III; Retrospective Study.

Incidence and risk factors for shoulder stiffness after open and arthroscopic rotator cuff repair.

INTRODUCTION: The aim of this study was to estimate the incidence of stiffness during the first 6 months after rotator cuff repair and to evaluate postoperative stiffness with respect to its risk factors and its influence on the outcome at 6 months postoperatively. METHODS: In a prospective cohort of 117 patients (69 women, 48 men; average age 59) from our institutional rotator cuff registry, who underwent either arthroscopic (n = 77) or open (n = 40) rotator cuff repair, we measured shoulder range of motion (ROM) at 3 and 6 months post-surgery. We evaluated the incidence of stiffness and analyzed functional outcomes, comparing various preoperative and intraoperative factors in patients with stiffness to those without at the 6-month mark. RESULTS: Shoulder stiffness was observed in 31% of patients (36/117) at 3 months postoperatively, decreasing to 20% (23/117) at 6 months. No significant link was found between stiffness at 6 months and demographic factors, preoperative stiffness, tear characteristics, or the type of repair. Notably, patients undergoing arthroscopic repair exhibited a 4.3-fold higher risk (OR 4.3; 95% CI 1.2-15.6, p = 0.02) of developing stiffness at 6 months compared to those with mini-open repair. Despite these differences in stiffness rates, no significant variation was seen in the American Shoulder and Elbow Surgeons (ASES) score, Single Assessment Numeric Evaluation (SANE) score, or Visual Analog Scale (VAS) scores at 6 months between the groups. CONCLUSION: The incidence of postoperative shoulder stiffness following rotator cuff repair was substantial at 31% at 3 months, reducing to 20% by 6 months. Mini-open repair was associated with a lower 6-month stiffness incidence than arthroscopic repair, likely due to variations in rehabilitation protocols. However, the presence of stiffness at 6 months post-surgery did not significantly affect functional outcomes or pain levels.

Affordances for throwing: An uncontrolled manifold analysis.

Movement systems are massively redundant, and there are always multiple movement solutions to any task demand; motor abundance. Movement consequently exhibits 'repetition without repetition', where movement outcomes are preserved but the kinematic details of the movement vary across repetitions. The uncontrolled manifold (UCM) concept is one of several methods that analyses movement variability with respect to task goals, to quantify repetition without repetition and test hypotheses about the control architecture producing a given abundant response to a task demand. However, like all these methods, UCM is under-constrained in how it decomposes a task and performance. In this paper, we propose and test a theoretical framework for constraining UCM analysis, specifically the perception of task-dynamical affordances. Participants threw tennis balls to hit a target set at 5m, 10m or 15m, and we performed UCM analysis on the shoulder-elbow-wrist joint angles with respect to variables derived from an affordance analysis of this task as well as more typical biomechanical variables. The affordance-based UCM analysis performed well, although data also showed thrower dynamics (effectivities) need to be accounted for as well. We discuss how the theoretical framework of affordances and affordance-based control can be connected to motor abundance methods in the future.

[Research progress of ultrasound in diagnosis and treatment of shoulder joint diseases].

Objective: To review the research progress of ultrasound in the diagnosis and treatment of shoulder diseases, in order to provide a theoretical basis for the further development of ultrasound in shoulder surgery. Methods: The recent literature on the application of ultrasound in the shoulder joint was extensively reviewed. The application of ultrasound in the diagnosis and treatment of shoulder joint diseases, and the advantages and disadvantages of ultrasound were analysed, and the development trend of ultrasound technology in the shoulder joint area was prospected. Results: At present, the diagnosis of shoulder joint diseases mainly relies on MRI, however, with the development of ultrasound technology, ultrasound with the characteristics of convenient, reliable, and real-time dynamic evaluation is more and more recognized in the diagnosis process of shoulder joint diseases, combined with three-dimensional ultrasound, ultrasound intervention, and elastography can improve the accuracy, sensitivity, and specificity of the diagnosis, and is suitable for the diagnosis and treatment of various shoulder joint diseases, which is expected to carry out early prevention of shoulder joint diseases in the future and achieve more refined and minimally invasive treatment. Conclusion: Ultrasound technology has wide application prospect in shoulder joint diseases, but it is still in the developing stage, and the subjective dependence needs to be solved further.