Glenohumeral motion: review of measurement techniques

Chest Exercises: Movement and Loading of Shoulder, Elbow and Wrist Joints

Injuries to the shoulder are very common in sports that involve overhead arm or throwing movements. Strength training of the chest muscles has the potential to protect the shoulder from injury. Kinematic and kinetic data were acquired in 20 healthy subjects (age: 24.9 ± 2.7 years) using motion capture, force plates for the bench press exercises and load cells in the cable for the cable pulley exercises with 15% and 30% of body weight (BW). Joint ranges of motion (RoM) and joint moments at the shoulder, elbow and wrist were derived using an inverse dynamics approach. The maximum absolute moments at the shoulder joint were significantly larger for the cable pulley exercises than for the bench press exercises. The cable cross-over exercise resulted in substantially different joint angles and loading patterns compared to most other exercises, with higher fluctuations during the exercise cycle. The present results indicate that a combination of bench press and cable pulley exercises are best to train the full RoM and, thus, intra-muscular coordination across the upper limbs. Care has to be taken when performing cable cross-over exercises to ensure proper stabilisation of the joints during exercise execution and avoid joint overloading.

Measurement of normal and pathological mandibular and temporomandibular joint kinematics: A systematic review

Motion of the mandible and temporomandibular joint (TMJ) plays a pivotal role in the function of the dentition and associated hard and soft tissue structures, and facilitates mastication, oral communication and access to respiratory and digestive systems. Quantification of TMJ kinematics is clinically relevant in cases of prosthetic rehabilitations, TMJ disorders, osteoarthritis, trauma, tumour resection and congenital abnormalities, which are known to directly influence mandibular motion and loading. The objective of this systematic review was to critically investigate published literature on historic and contemporary measurement modalities used to quantify in vivo mandibular and TMJ kinematics in six degrees of freedom. The electronic databases of Scopus, Web of Science, Medline, Embase and Central were searched and 109 relevant articles identified. Publication quality was documented using a modified Downs and Black checklist. Axiography and ultrasonic tracking are commonly employed in the clinical setting due to their simplicity and capacity to rapidly acquire low-fidelity mandibular motion data. Magnetic and optoelectronic tracking have been used in combination with dental splints to produce higher accuracy measurements while minimising skin motion artefact, but at the expense of setup time and cost. Four-dimensional computed tomography provides direct 3D measurement of mandibular and TMJ motion while circumventing skin motion artefact entirely, but employs ionising radiation, is restricted to low sampling frequencies, and requires time-consuming image processing. Recent advances in magnetic tracking using miniature sensors adhered to the teeth in combination with intraoral scanning may facilitate rapid and high precision mandibular kinematics measurement in the clinical setting. The findings of this review will guide selection and application of mandibular and TMJ kinematic measurement for both clinical and research applications.

Position of the rotator cuff footprint in relation to the centre of rotation of the humeral head

BACKGROUND

The objective of the present study was to determine the size and position of the rotator cuff moment arms constructed from the cuff footprints, incident on the line of force acting through the humeral head.

METHODS

Five humeri were dissected, leaving the footprints of the rotator cuff intact. Each of the rotator cuff footprints and the cartilage/calcar interface were digitized and the articular surface was scanned using a high precision surface laser scanner. All of the data were merged into the same coordinate system. The centroid of each cuff footprint, centroid of the articular surface of the humerus (G) and the centroid of the articular surface of the glenoid (P) were calculated. Moment arms were measured as the intersection of a perpendicular line of force from each footprint centroid onto the resultant line of force to the centroid of the Glenoid (P).

RESULTS

The mean moment arms of the supraspinatus, infraspinatus and subscapularis muscles were incident close to the centroid (G), whereas teres minor was lateral to the centroid, consistently.

CONCLUSIONS

The teres minor moment arm aligned distal to the centroid of the sphere, consistently. The results may provide an understanding of the function of each muscle as a mobilizer or stabilizer of the glenohumeral joint. Further investigation is necessary.

Dynamic Three-Dimensional Shoulder Mri during Active Motion for Investigation of Rotator Cuff Diseases

Background

MRI is the standard methodology in diagnosis of rotator cuff diseases. However, many patients continue to have pain despite treatment, and MRI of a static unloaded shoulder seems insufficient for best diagnosis and treatment. This study evaluated if Dynamic MRI provides novel kinematic data that can be used to improve the understanding, diagnosis and best treatment of rotator cuff diseases.

Methods

Dynamic MRI provided real-time 3D image series and was used to measure changes in the width of subacromial space, superior-inferior translation and anterior-posterior translation of the humeral head relative to the glenoid during active abduction. These measures were investigated for consistency with the rotator cuff diseases classifications from standard MRI.

Results

The study included: 4 shoulders with massive rotator cuff tears, 5 shoulders with an isolated full-thickness supraspinatus tear, 5 shoulders with tendinopathy and 6 normal shoulders. A change in the width of subacromial space greater than 4mm differentiated between rotator cuff diseases with tendon tears (massive cuff tears and supraspinatus tear) and without tears (tendinopathy) (p = 0.012). The range of the superior-inferior translation was higher in the massive cuff tears group (6.4mm) than in normals (3.4mm) (p = 0.02). The range of the anterior-posterior translation was higher in the massive cuff tears (9.2 mm) and supraspinatus tear (9.3 mm) shoulders compared to normals (3.5mm) and tendinopathy (4.8mm) shoulders (p = 0.05).

Conclusion

The Dynamic MRI enabled a novel measure; ‘Looseness’, i.e. the translation of the humeral head on the glenoid during an abduction cycle. Looseness was better able at differentiating different forms of rotator cuff disease than a simple static measure of relative glenohumeral position.

The centre of rotation of the shoulder complex and the effect of normalisation

Shoulder motions consist of a composite movement of three joints and one pseudo-joint, which together dictate the humerothoracic motion. The purpose of this work was to quantify the location of the centre of rotation (CoR) of the shoulder complex as a whole. Dynamic motion of 12 participants was recorded using optical motion tracking during coronal, scapular and sagittal plane elevation. The instantaneous CoR was found for each angle of elevation using helical axes projected onto the three planes of motion. The location of an average CoR for each plane was evaluated using digitised and anthropometric measures for normalisation. When conducting motion in the coronal, scapular, and sagittal planes, respectively, the coefficients for locating the CoRs of the shoulder complex are −61%, −61%, and −65% of the anterior–posterior dimension – the vector between the midpoint of the incisura jugularis and the xiphoid process and the midpoint of the seventh cervical vertebra and the eighth thoracic vertebra; 0%, −1%, and −2% of the superior–inferior dimension – the vector between the midpoint of the acromioclavicular joints and the midpoint of the anterior superior iliac spines; and 57%, 57%, and 78% of the medial–lateral dimension −0.129 times the height of the participant. Knowing the location of the CoR of the shoulder complex as a whole enables improved participant positioning for evaluation and rehabilitation activities that involve movement of the hand with a fixed radius, such as those that employ isokinetic dynamometers.

Revisit to scapular dyskinesis: three-dimensional wing computed tomography in prone position

BACKGROUND

Three-dimensional (3D) wing computed tomography (CT) showed a high inter-rater reliability in assessing scapular dyskinesis.

METHODS

The 330 scapular movements of 165 patients were classified into 4 types by 7 blinded observers. Then, 3D wing CT was performed with patients prone, and 4 blinded observers measured 5 angles, consisting of upward rotation (UR) superior translation (ST), anterior tilting (AT), protraction (PRO), and internal rotation (IR). The inter-rater reliability (IRR) of 2 methods was calculated, and cutoff values were determined for the 5 angles on the 3D wing CT images.

RESULTS

The IRR was 0.783 for the observational method of scapular dyskinesis and 0.981 for 3D wing CT in the prone position. UR and ST angles were significantly larger in type 3 more than in the other types (P < .001, P < .001), and the AT angle showed a similar pattern in type 1 (P < .001). The PRO angle was significantly larger in types 1, 2, and 3 more than in type 4 (P < .001, P < .001, P = .013), and the IR angle was significantly larger in type 2 more than in the other types (P < .001). The cutoff values of the 5 angles were UR, 117°; ST, 90°; AT, 8°; PRO, 99°; and IR, 51°. The UR angle showed a significant correlation with glenohumeral internal rotation deficit (odds ratio, 0.436; P = .029) and the IR angle with MDI (odds ratio, 8.947; P = .048).

CONCLUSION

The patients with a high UR angle showed a low rate of glenohumeral internal rotation deficit and those with a high IR angle had a high rate of the MDI in affected shoulder by the determinant of the cutoff value of the 5 angles.

LEVEL OF EVIDENCE

Level III, development of diagnostic criteria with nonconsecutive patients, diagnostic study.

How to assess scapular dyskinesis precisely: 3-dimensional wing computer tomography--a new diagnostic modality

BACKGROUND

Aberrations in scapular motion are believed to be associated with the presence of shoulder or elbow pathologies. There are many methods to evaluate scapular kinematics, but they have certain limitations. Nevertheless, it is believed that appropriate rehabilitation for each type of scapular dyskinesis is important.

METHODS

Eighty-nine athletes were videotaped and seven blinded observers categorized scapular dyskinesis into 4 types, which was followed by 3-dimensional (3D) wing computer tomography (CT). Four blinded examiners evaluated 5 angles [upward rotation (UR), internal rotation (IR), anterior tilting (AT), superior translation (ST), and protraction (PRO)] on the 3D wing CT. Inter-rater reliability (IRR) was calculated for both the methods. CT scan measurements were compared with the 4 observational types to establish the validity.

RESULTS

The IRR with observational assessment of scapular dyskinesis into 4 types was good, 0.780. The 3D wing CT analysis had a very high IRR, 0.972. There was a statistically significant correlation between observational assessment and 3D wing CT analysis. The UR angle, ST angle in type 3 scapular dyskinesis, and AT angle in type 1 scapular dyskinesis were increased as compared with those in the other types of scapular dyskinesis. All these measurements were made in the resting position of the scapula.

CONCLUSION

The 3D wing CT analysis allows precise quantification of a position associated with scapular dyskinesis. Therefore, 3D wing CT can be considered as an alternative method for assessing scapular dyskinesis.

New dynamic three-dimensional MRI technique for shoulder kinematic analysis

PURPOSE

To establish a new imaging technique using dynamic MRI three-dimensional (3D) volumetric acquisition in real-time, on six normal shoulders for the analysis of the 3D shoulder kinematics during continuous motion.

MATERIALS AND METHODS

At first, a standard static acquisition was performed. Then, fast images were obtained with a multi-slice 3D balanced gradient echo sequence to get a real time series during the initial phase of shoulder abduction. Subsequently, the images were reconstructed; registered and the translational patterns of the humeral head relative to the glenoid and the size of the subacromial space were calculated. Additionally, the intraobserver reproducibility was tested.

RESULTS

The maximal abduction was on average 43° (30° to 60°) and the mean width of the subacromial space was 7.7 mm (SD: ±1.2 mm). Difference between extreme values and average values was low, respectively 2.5 mm on X-axis, 2 mm on Y-axis, 1.4 mm for the width of the subacromial space and 1.2° for the measure of the glenohumeral abduction.

CONCLUSION

This study reported a dynamic MRI protocol for the monitoring of shoulder 3D kinematics during continuous movement. The results suggest that there is no superior shift of the humeral head during the first phase of abduction.

Motion analysis of the glenohumeral joint during activities of daily living

The shoulder complex has a larger range of motion (ROM) than any other joint complex in the human body, leaving it prone to numerous injuries. Objective kinematic analysis could yield useful functional insights that may assist clinical practice. Non-invasive optoelectronic motion analysis techniques have been used to assess the shoulders of five healthy subjects performing ROM tasks and 10 functional tasks of daily living. The four most demanding tasks - touching the side and back of the head, brushing the opposite side of the head, lifting an object to shoulder height and lifting an object to head height, required 78%, 60%, 61% and 71%, respectively, of the glenohumeral elevation necessary for full abduction in the scapular plane for the 10 shoulders. This has implications for clinical practice where maximum arm elevation is commonly used to determine a patient's ability to return to work and other everyday activities.

Clinical assessment of external rotation for the diagnosis of anterior shoulder hyperlaxity

The aim of this study was to evaluate two methods of clinical assessment for external rotation of the shoulder to optimise the diagnosis of hyperlaxity in patients being selected for surgery for stabilisation of chronic anterior instability. External rotation was evaluated in 70 healthy student volunteers by two examiners (intertester study) using two methods of assessment at 15-day intervals (intratester study). The first method used was the protocol described for the Instability Severity Index Score (ISIS). In this case, the subject was evaluated in the sitting position, bilaterally with passive range of motion movements. The shoulder was considered hyperlax if ER1 was greater than 85°. With the second, so-called "elbow on the table" (EOT) method, the subject was evaluated in the decubitus dorsal position, unilaterally with passive range of motion. The subject was considered to be hyperlax if ER1 was greater than 90°. Kappa values for intra- and intertester agreement with the ISIS method were average, while they were satisfactory with the intraclass coefficient (ICC). Kappa values for inter- and intratester agreement with the EOT method were average and good, respectively. This tendency was confirmed by the ICC which went from good to excellent for the two examiners in both series of measurements using the EOT method, showing better reproducibility with this method. Our study confirms that the most reproducible method for assessing external rotation is obtained by unilateral assessment of the patient in the decubitus dorsal position, with passive range of motion. An ER1 of 90° is the necessary threshold for hyperlaxity because of elbow retropulsion with this method, which provides immediate and visual evaluation and eliminates the necessity of goniometry.