scapulohumeral rhythm

BACKGROUND: The rationale for the Latarjet procedure was described as the "triple blocking" effect. Satisfactory surgical outcomes have been reported after surgery. However, it has been reported that the "triple blocking" effect increases joint stability, but it does not fully restore it. Moreover, the procedure is nonanatomic and concerns remain regarding the effects. The study of scapulohumeral rhythm, which is a clinical parameter used for the functional evaluation of shoulder kinematics, can offer new perspectives on the rationale for the procedure...

BACKGROUND: Researchers have attempted to understand the underlying mechanism of the Latarjet procedure; however, its effects on shoulder kinematics have not been well studied. PURPOSE/HYPOTHESIS: The purpose was to analyze shoulder kinematics after the Latarjet procedure. It was hypothesized that the nonanatomic transfer of the coracoid process during the procedure would affect normal shoulder kinematics. STUDY DESIGN: Controlled laboratory study...

BACKGROUND: Reversed total shoulder arthroplasty (RTSA) is a standard surgical procedure for the treatment of rotator cuff tear arthropathy (CTA), aimed at restoring active arm elevation. Shoulder elevation relies on both scapulothroacic (ST) and glenohumeral (GH) motion, but RTSA computer planning primarily focuses on the GH joint due to challenges in visualizing scapulothroacic (ST) motion. RESEARCH QUESTION: Does the scapulohumeral rhythm, by means of the relative contributions of ST rotation and GH elevation per degree of arm elevation, in a longitudinal setting for up to two years postoperatively after RTSA for CTA change? METHODS: In a prospective longitudinal study, shoulder kinematics were studied in 20 patients (22 shoulders) before and at three, six, 12, and 24 months after RTSA implantation for CTA...

It is important to discuss the importance of synchronous balance between periscapular muscles for scapulothoracic motion and resultant scapulohumeral rhythm. Abnormalities in this balance can lead to scapular dyskinesia and winging, affecting shoulder motion and leading to impingement. Strategies exist to diagnose and differentiate between pathologies such as muscle paralysis (eg, trapezius or serratus anterior) or overactivity (eg, pectoralis minor). The physician should be aware of the role of diagnostic imaging, as well as the unique considerations for patients with Ehlers-Danlos syndrome...

A comprehensive review of scapular pathologies and their effect on shoulder function is necessary to determine the best treatment options. The coordinated motion between the scapulothoracic and glenohumeral joints is essential for shoulder motion and depends on the balanced activity of the periscapular muscles. Disruption in these muscles can cause abnormal scapular motion and compensatory glenohumeral movements, leading to misdiagnosis or delayed diagnosis. Scapular pathologies can arise from muscle overactivity or underactivity/paralysis, resulting in a range of scapulothoracic abnormal motion (STAM)...

NESM-γ is an upper-limb exoskeleton to train motor functions of post-stroke patients. Based on the kinesiology of the upper limb, the NESM-γ includes a four degrees-of-freedom (DOF) active kinematic chain for the shoulder and elbow, along with a passive chain for self-aligning robotic joint axes with the glenohumeral (GH) joint's center of rotation. The passive chain accounts for scapulohumeral rhythm and trunk rotations. To assess self-aligning performance, we analyzed the kinematic and electromyographic data of the shoulder in eight healthy subjects performing reaching tasks under three experimental conditions: moving without the exoskeleton (baseline), moving while wearing the exoskeleton with the passive DOFs properly functioning, i...

BACKGROUND: Few studies have investigated the kinematics after reverse total shoulder arthroplasty (RTSA). This study aimed to compare the shoulder kinematics in RTSA patients during shoulder abduction on the scapular plane with and without a load and yield information regarding the function of stabilizing the joints against gravity for the functional assessment of the shoulder after RTSA, which could lead to changes in postoperative rehabilitation treatment. METHODS: Twenty RTSA patients (7 men, 13 women; mean age: 78...

The shoulder joint complex in the overhead athlete is organized to effectively transfer the proximally generated forces distally into the arm. The organization also protects the joints and anatomic structures against the repetitive high velocities, large ranges of motions, and compressive, shear, translational, and distraction loads in the overhead motion while placing the hand in the "launch window." Coupling of the movements of the scapula, clavicle, and humerus results in scapulohumeral rhythm (SHR). Effective SHR requires the clavicle and scapula-and, at times, the mechanically linked claviscapular segment-to move the arm into the task-specific position and motion and requires the humerus to move through the ranges of motion to achieve the specific task in the throwing motion...

BACKGROUND: Compromised abduction ability after reverse shoulder arthroplasty is primarily linked to limited glenohumeral range of motion while scapulothoracic mobility can typically be maintained. Glenohumeral joint forces strongly depend on the resulting scapulohumeral rhythm, however, an association between the acting muscle and joint forces and the subject-specific scapulohumeral rhythm after reverse shoulder arthroplasty has not been established. METHODS: Eleven reverse shoulder arthroplasty patients were divided into groups of poor and excellent abduction ability...

Volleyball players develop shoulder sports-related adaptations due to repetitive overhead motions. It is essential to differentiate between these sports-related adaptations and pathological patterns in clinical assessments, particularly on scapular resting posture and scapulohumeral rhythm. Using an electromagnetic tracking system, the 3D shoulder kinematics of 30 male elite asymptomatic volleyball players and a matching control group were recorded at rest and in eight humeral elevation positions, in 15-degree increments from 15 to 120 degrees...

BACKGROUND: Although visual examination and palpation are used to assess shoulder motion in clinical practice, there is no consensus on shoulder motion under dynamic and static conditions. This study aimed to compare shoulder joint motion under dynamic and static conditions. METHODS: The dominant arm of 14 healthy adult males was investigated. Electromagnetic sensors attached to the scapular, thorax, and humerus were used to measure three-dimensional shoulder joint motion under dynamic and static elevation conditions and compare scapular upward rotation and glenohumeral joint elevation in different elevation planes and angles...

BACKGROUND: The alteration of scapular kinematics can predispose patients to shoulder pathologies and dysfunction. Previous literature has associated various types of shoulder injuries with scapular dyskinesis, but there are limited studies regarding the effect that proximal humeral fractures (PHF) have on scapular dyskinesis. This study aims to determine the change in scapulohumeral rhythm following treatment of a proximal humerus fracture as well as differences in shoulder motion and functional outcomes among patients who presented with or without scapular dyskinesis...

BACKGROUND: There is very limited information about the changes in shoulder kinematics in patients with reverse shoulder arthroplasty. The aim of the study was to investigate the changes in the scapulohumeral rhythm and shoulder kinematics over time after the reverse shoulder procedure. METHODS: Nineteen patients with reverse shoulder arthroplasty (age: 65.8 ± 10.3 years) were included to the study. During arm elevation in the sagittal and scapular planes, operated shoulder kinematics (humerothoracic elevation, glenohumeral elevation, scapulohumeral rhythm, and scapular rotations) were assessed using an electromagnetic tracking system at the postoperative 3rd, 6th, and 18th months...

HYPOTHESIS: The purpose of this study was to analyze the SHR of patients diagnosed with small (SRCTs) and massive rotator cuff tears (MRCTs), adhesive capsulitis (AC), and glenohumeral osteoarthritis (GH-OA) and compare their measurements to those of patient controls with healthy shoulders using DDR. We hypothesize that various diagnoses will vary with regards to SHR. METHODS: The sequences of pulsed radiographs collated in DDR to create a moving image were prospectively analyzed during humeral abduction in normal controls and in 4 distinct shoulder pathology groups: SRCT, MRCT, AC, and GH-OA...

INTRODUCTION: Reverse shoulder arthroplasty (RSA) is a valid and increasingly popular treatment option in eccentric arthrosis and cuff arthropathy. We know that the deltoid is the motor of RSA. However, the role of scapular motion has been poorly documented in the literature. The aim of our study is to analyze and quantify the role of the scapular contribution in the functional outcome of patients undergoing RSA. MATERIALS AND METHODS: Fourteen patients who underwent primary RSA were included in the study...

BACKGROUND: Due to the influence of spinal and respiratory movements, it is difficult to accurately measure the range of motion of each joint. OBJECTIVE: To conduct a three-dimensional (3D) measurement of each joint in the shoulder complex in different postures in the sagittal plane of the upper extremity. METHODS: Thirteen healthy adults with no history of shoulder surgery for trauma or chronic pain were enrolled in the present study. The computed tomography (CT) imaging data of the shoulder complex were acquired in four postures via the reconstruction and alignment of 3D images...

Multiple papers have described aspects of treatment of acromioclavicular (AC) joint injuries. Most have emphasized aspects of surgical treatment, and some papers have addressed non-operative treatment. Few papers have highlighted the specific pathoanatomy of an AC joint injury or have described methods of evaluating the 3-dimensional pathomechanics resulting from the pathoanatomical injury. This paper is based on 3 observations: (1) AC joint injuries exist and present on a spectrum of pathoanatomy; (2) The effect of the pathoanatomy on normal AC joint mechanics to produce pathomechanics is dependent on the extent of the pathoanatomy; and (3) Treatment protocols should be developed to address the specific pathoanatomy to optimize the mechanics...

Background: Stabilizing exercises reduce pain intensity, improves shoulder position and scapular function, and provides an appropriate strategy for the improvement of scapular dyskinesia. The purpose of this study was to investigate the effect of six weeks of stability exercises (stretching-strengthening) on joint proprioception, strength, and range of motion of the glenohumeral joint in female tennis players with scapular dyskinesia. Methods: Thirty-six female elite tennis players with scapular dyskinesia in both experimental and control groups participated in this study...

Background: Reverse shoulder arthroplasty (RSA) is associated with high rates of midterm complications including scapular notching, implant wear, and mechanical impingement. Scapulo-humeral rhythm (SHR), described by Codman in the 1920's, is defined as the ratio of glenohumeral motion to scapulothoracic motion. SHR is used as an indicator of shoulder dysfunction, as alterations in SHR can have profound implications on shoulder biomechanics. The determination of SHR can be hindered by soft-tissue motion artifacts and high radiation burdens associated with traditional surface marker or fluoroscopic analysis...

Although shoulder kinematics have been analyzed by various methods, dynamic shoulder motion is difficult to track. This study aimed to validate the shoulder kinematic analysis using upright four-dimensional computed tomography (4DCT) and to compare the results with optical three-dimensional motion capture. During active elevation, bilateral shoulders of 10 healthy volunteers were tracked using 4DCT and motion capture. The scapulothoracic and glenohumeral rotations and the scapulohumeral rhythm (SHR) at each position were calculated, and the differences between 4DCT and motion capture were compared...