FIGURE 1 - uploaded by Amitabh Dashottar
Content may be subject to copyright.
Source publication
Controlled laboratory study using a repeated-measures approach.
To quantify the amount of strain on cadaver posterior shoulder tissues during simulated clinical tests across different tissue conditions.
Several clinical tests are used to quantify posterior glenohumeral joint (GHJ) tissue tightness; however, the ability of these tests to directly as...
Context in source publication
Context 1
... 20% experimental posterior capsule contraction has been shown to alter humeral head translations in cadaver specimens. 6 For these last 2 shoulder conditions, the strain gauges were fixed to the capsule in 2 locations ( Figure 1). One gauge was in the middle region, defined as the capsule between 9:00 on the glenoid rim and 9:00 on the humeral head, and was oriented horizontally. ...
Citations
... Conflicts of interest: The authors, their immediate families, and any research foundation with which they are affiliated have not received any financial payments or other benefits from any commercial entity related to the subject of this article. (1,2) , intraclass correlation coefficient; CI, confidence interval; IR, internal rotation; ER, external rotation. ...
Background
The relationship between lower mobility, as measured by the elbow forward translation motion (T-motion) test, a new indicator of shoulder joint complex movement that measures elbow position when both dorsal hands are placed on the iliac crest while in a sitting position, and the parameters calculated by ultrasonography is unknown. The purpose of this study was to investigate the limiting factors of T-motion through motion analysis of the humeral head and rotator cuff muscles using ultrasonography in college baseball players.
Methods
Thirteen college baseball players participated in this cross-sectional study. The shortest distance from the posterior edge of the glenoid to the humeral head was measured in the static and T-motion positions, and the difference was calculated as the humeral head translation. The velocity of the infraspinatus was calculated during shoulder internal/external rotation using the particle image velocimetry method. These parameters were compared between the throwing and nonthrowing sides to examine the limiting factors of T-motion.
Results
This study indicated moderate-to-good reliability for the parameters calculated by ultrasonography. The mean anterior translation distance was significantly greater on the throwing side than on the nonthrowing side (r = 0.56, P = .015). The mean velocity of infraspinatus during internal rotation was significantly lower on the throwing side than on the nonthrowing side (r = 0.51, P = .028).
Conclusion
Increased anterior translation of the humeral head and decreased the velocity of infraspinatus are likely correlated with reduced T-motion mobility in college baseball players. These methods showed potential for physical therapy assessment and intervention to prevent shoulder dysfunction.
... 19 Therefore, the management of GIRD may contribute to the performance of table tennis players. Some factors, such as posterior capsule tightness 21,22 and muscular tightness, 1 have been considered to be related to GIRD. Researchers found a thickened posterior capsule by arthroscopic, 23 ultrasound, 24 and magnetic resonance imaging 25 in overhead players, but additional related research on table tennis is required. ...
Objective:
(1) To investigate glenohumeral internal rotation deficit (GIRD: a difference in internal rotation of 15.6° or more between dominant and nondominant shoulders) and its correlation with self-reported shoulder pain in table tennis players. (2) To find the optimal cutoff point for the difference in the internal rotation (IR) range of motion (ROM) between dominant and nondominant shoulders of self-reported shoulder pain.
Design:
The IR ROM of both shoulders of 46 table tennis players was measured in the supine and side-lying positions, the external rotation ROM was measured in the supine position.
Results:
Significant differences existed in IR ROM between the two sides in the supine (z = 6.53, p < 0.001) and side-lying positions (z = 5.67, p < 0.001). Self-reported shoulder pain was associated with GIRD (OR = 6.86, 95% CI: 1.752-26.832, P = 0.006). The cutoff points for the difference in IR ROM between the sides of self-reported shoulder pain were 17.9° in the supine position and 11.1° in the side-lying position.
Conclusions:
Table tennis players exhibited GIRD. There was a correlation between GIRD and self-reported shoulder pain in the past year; therefore, GIRD may be a risk factor for shoulder pain in table tennis players.
... Es importante considerar que la modificación a la técnica original, aplicando una rotación posterior del tronco, orienta al hombro en el plano escapular disminuyendo de esta forma los síntomas producto de la posición de 90° de flexión del hombro (23,42). Además esta posición incrementa selectivamente la tensión sobre la cápsula posterior (43,44). A pesar de estos fundamentos metodológicos y biomecánicos, es importante señalar que la descripción original del cuadro clínico del SPSA no menciona la rigidez de la cápsula posterior como origen del dolor, incluso es poco frecuente que los pacientes con SPSA presenten disminución del rango de movimiento de rotación interna glenohumeral (1,2,45). ...
Objetivo: Determinar la efectividad clínica de adicionar el ejercicio de elongación de “estiramiento acostado” a un programa de ejercicios específicos en pacientes con síndrome de pinzamiento subacromial (SPSA). Diseño: Estudio clínico aleatorizado ciego simple. Método: Se reclutaron en forma prospectiva 64 pacientes con diagnóstico clínico e imagenológico de SPSA, quienes fueron asignados a dos grupos al azar. El grupo control (n = 32) recibió un programa de ejercicios de 12 semanas, el grupo de
intervención (n = 32) recibió el mismo programa más un ejercicio de elongación de la cápsula posterior. Ambos grupos fueron evaluados al inicio y al finalizar el tratamiento. La medida de resultado primaria fue la función del hombro con el cuestionario Constant-Murley, las medidas de resultado secundarias fueron la función de la extremidad superior con el cuestionario DASH y el dolor en reposo y al movimiento con la escala visual analógica (EVA). Resultados: Todos los pacientes completaron el estudio. Al finalizar el tratamiento el cuestionario Constant-Murley mostró una diferencia de 3 puntos (p = 0.864) y el cuestionario DASH una diferencia fue de 2 puntos (p = 0.941), ambas diferencias son a
favor del grupo de intervención, pero no son ni clínica ni estadísticamente significativas. Para la EVA en reposo la diferencia fue de 0,2 cm (p = 0,096) y la EVA al movimiento fue de 0,4 cm (p = 0,378), en ambas la diferencia en la reducción del dolor
fue mayor en el grupo control. Conclusión: A corto plazo, adicionar el ejercicio de “estiramiento acostado” no proporciona un beneficio clínico ni estadísticamente significativo con respecto a la
mejora funcional o la reducción del dolor en pacientes con SPSA
... This procedure was repeated twice. 23,24 Lower values in the low flexion test indicated less shoulder IR ROM and possible posterior capsule tightness. 23 Pectoralis Minor Length. ...
Context:
Understanding the musculoskeletal adaptations in the shoulder complex of varying ages of tennis athletes may suggest preventive protocols and conditioning and rehabilitation programs to this population. This study aimed to generate a bilateral descriptive profile of shoulder flexibility, scapular and clavicular position, and muscle strength in pediatric and adult amateur tennis athletes. The outcome measures were compared between groups and sides. The number and percentage of athletes "at risk" according to cutoff values for shoulder range of motion (ROM) were also analyzed.
Design:
Cross-sectional study.
Methods:
36 pediatric and 28 adult amateur tennis athletes were tested. Outcome measures were ROM of shoulder flexion, abduction, internal and external rotation, posterior capsule tightness, pectoralis minor index (PMI), scapular upward rotation, clavicular elevation, and strength of the external rotators, serratus anterior, and lower trapezius of the dominant/nondominant sides.
Results:
Pediatric athletes had greater dominant side external rotation (P = .01) and total ROM (P = .04), increased Low Flexion test (P = .01), and decreased PMI (P = .01) compared with the adults. Bilaterally, the pediatric athletes had greater dominant side external rotation ROM (P < .01) and decreased PMI (P = .002) as compared with their nondominant side, whereas the adults displayed lower values on posterior capsule tightness (P = .01) and decreased PMI (P = .02) on their dominant side compared with their nondominant side. For the remaining outcomes, no interaction effects were observed. The cutoff values for shoulder ROM showed that several athletes were "at risk" of shoulder problems.
Conclusion:
Upper extremity adaptations at the shoulder are present in both pediatric and adult tennis athletes. These data can assist clinicians in better understanding the biomechanical adaptations in the shoulder of amateur tennis athletes in different age groups.
... 36 Participants were required to have PCT, determined with the Low Flexion Test (LFT). 8,37 The LFT is performed with the individual's arm supported at 60°of flexion before allowing glenohumeral IR to reach the end of passive motion. Subsequently, a digital inclinometer measures the angle between the forearm and horizontal. ...
... Subsequently, a digital inclinometer measures the angle between the forearm and horizontal. 8,37 A 7°decrease compared with the contralateral side indicates PCT. 38 The LFT is a valid and reliable measurement specific to the posterior glenohumeral capsule. ...
... 38 The LFT is a valid and reliable measurement specific to the posterior glenohumeral capsule. [37][38][39][40] For kinematic data collection, participants were also required to have »150°of active arm elevation. ...
Background
Posterior capsule tightness (PCT) is associated with shoulder pain and altered shoulder kinematics, range of motion (ROM), external rotation (ER) strength, and pain sensitization.
Objective
To assess the effects of two interventions on shoulder kinematics, Shoulder Pain and Disability Index (SPADI) scores, ROM, strength, and pressure pain threshold (PPT) in individuals with PCT and shoulder impingement symptoms.
Methods
In this prospectively registered randomized controlled trial 59 individuals were randomized to either an Experimental Intervention Group (EIG, n=31) or a Control Intervention Group (CIG, n=28). The low flexion (LF) test was used to determine the presence of PCT. Shoulder kinematics, SPADI scores, internal rotation (IR) and ER ROM, ER strength, and PPT were measured pre- and post-treatment. Those in the EIG received an intervention specific to pain and PCT and those in the CIG received a non-specific intervention, both 4 weeks in duration.
Results
Individuals in the EIG demonstrated more scapular upward rotation (P=.03; mean difference (MD)=3.3°; 95% Confidence Interval (CI)=1.3°, 4.9°) and improved value on the LF test (P=.02; MD=4.6°; 95%CI=0.7°, 8.6°) than those in the CIG after treatment. Both groups presented less anterior (P<.01; MD=-0.7mm; 95%CI=-1.3mm, -0.2mm) and superior (P<.01; MD=-0.5mm; 95%CI=-0.9mm, -0.2mm) humeral translations, decreased SPADI score (P<.01; MD=-23.6; 95%CI=-28.7, -18.4), increased IR ROM (P<.01; MD=4.6°; 95%CI=1.8°, 7.8°) and PPTs for upper trapezius (P<.01; MD=60.1kPa; 95%CI=29.3kPa, 90.9kPa), infraspinatus (P=.04; MD=47.3kPa; 95%CI=2.1kPa, 92.5kPa), supraspinatus (P<.01; MD=63.7kPa; 95%CI=29.6kPa, 97.9kPa), and deltoid (P<.01; MD=40.9kPa; 95%CI=12.3kPa, 69.4kPa) after treatment.
Conclusion
The experimental intervention was more effective at improving PCT as measured through changes in the LF test. No benefit of the specific approach over the non-specific intervention was noted for the remaining variables.
... PST has historically been defined through side-to-side differences in measures of horizontal adduction and internal rotation [5,16]. A third test was proposed by Borstad and Dashottar [17], who performed a cadaveric study on 8 fresh cadaveric shoulders to determine the strain on the structures of the posterior shoulder with 5 simulated clinical tests or movements of the humerus. They found greatest strain on the posterior capsule using a position of 60°flexion and internal rotation, and concluded that this test was valid for the purpose of evaluating glenohumeral joint posterior capsule flexibility. ...
... They found greatest strain on the posterior capsule using a position of 60°flexion and internal rotation, and concluded that this test was valid for the purpose of evaluating glenohumeral joint posterior capsule flexibility. The authors named this movement 'low flexion' [17] and recommended its use in the assessment of PST. ...
... Defining PST more clearly is important for the purposes of research and clinical practice. Based on cadaveric studies [17,28], reliability data [29,30] and its historical origins [5,16], we have defined PST in terms of the three measures described above; Salamh et al. [20] 'PST has been defined as a limitation of the extensibility within the posterior soft tissue of the shoulder including both contractile and non-contractile elements as well as osseous changes as seen in the form of humeral torsion within the overhead athlete through training adaptations' (pg 179) ...
Background:
Although posterior shoulder tightness (PST) has been associated with shoulder pathology and altered glenohumeral joint kinematics, uncertainty remains regarding its cause and definition. To understand the efficacy of treatments for PST, it must be possible to identify people with PST for the purposes of research and clinical decision-making. Clinical tests for PST must demonstrate acceptable levels of measurement reliability in order to identify the condition and to evaluate the response to intervention. There is currently a lack of research describing intersession reliability for measures of PST. The aim of this study was to quantify the inter-session reliability for three clinical tests used to identify PST over a 6-10 week interval.
Methods:
A convenience sample of 26 asymptomatic adult participants (52 shoulders) were recruited from a university setting over a five-month duration. Participants attended the human movement laboratory for measurement of glenohumeral joint internal rotation, horizontal adduction and low flexion on two occasions separated by an interval of 6-10 weeks.Intra-class correlation coefficients were calculated from the mean square values derived from the within-subject, single factor (repeated measures) ANOVA. Test-retest measurement stability was evaluated by calculating the standard error of measurement and the minimum detectable change for each measurement.
Results:
All 3 tests demonstrated good intersession intra-rater reliability (0.86-0.88), and the standard error of measurement (95%) were 7.3° for glenohumeral horizontal adduction, 9.4° for internal rotation, and 6.9° for low flexion. The minimum detectable change for glenohumeral horizontal adduction was 10.2°, internal rotation was 13.3°, and low flexion was 9.7°.
Conclusion:
In this population of people without symptoms, the 3 measures of PST all demonstrated acceptable inter-session reliability. The standard error of measurement and minimum detectable change results can be used to determine if a change in measures of PST are due to measurement error or an actual change over time.
... Subsequently, the posterior capsule was divided into the superior posterior capsule (Sup-PC), middle posterior capsule (Mid-PC), and inferior posterior capsule (Inf-PC) (Bey et al., 2005). For the right shoulder, the Sup-PC, Mid-PC, and Inf-PC were defined as the areas corresponding to that between 10 and 11 o'clock, around 9 o'clock, and between 7 and 8 o'clock on a clock face, respectively (Borstad and Dashottar, 2011;Izumi et al., 2008). The glenoid was then cut according to the incisions between the Sup-PC and Mid-PC, and between the Mid-PC and Inf-PC, to create bone-capsule-bone specimens with a width of approximately 10 mm (Bey et al., 2005) (Fig. 1). ...
Although shear wave elastography (SWE) has been used to indirectly measure passive tension in muscle tissues, it is unknown whether SWE can adequately evaluate passive tension in capsule tissues. This study investigated the relationship between the shear modulus and passive tension in the posterior shoulder capsule using SWE. Ten posterior middle and ten posterior inferior shoulder capsules were dissected from ten fresh-frozen cadavers; humeral head-capsule-glenoid specimens were created from each capsule. The humeral head and glenoid were immobilized with clamps in a custom-built device. Loads (0-400 g, in 25-g increments) were applied to each capsule via a pulley system; elasticity was simultaneously measured using SWE. The elasticity-load relationship of each tested capsule was analyzed by fitting a least-squares regression line to the data. Elasticity change due to creep or hysteresis effects was evaluated by comparing the elastic modulus for a 100-g load during and after the stepwise application of the loads. The observed relationship between the shear modulus and passive capsule tension was highly linear for all twenty tested capsules (p < 0.01). The mean coefficient of determination was 0.882 ± 0.075 and 0.901 ± 0.050 for the posterior middle and posterior inferior capsules, respectively. There was no difference in the shear modulus between the two 100-g load assessments for both the posterior middle (p = 0.205) and posterior inferior capsules (p = 0.161). Thus, SWE is a valid and useful method for indirectly evaluating the change in the passive tension under loading in specific posterior shoulder capsule.
... Most importantly, they are inherently limited to measuring external surface strains, instead of full-field internal strains. Conventional strain gauges [10][11][12][13][14] can only measure strain at single locations and need to be glued to a surface on the specimens. The photoelasticity method [15][16][17] needs to be performed on replica models made with photoelastic materials or on photoelastic sheets that are glued to bone specimens. ...
Loosening of the glenoid component is the most common cause of failure of total shoulder arthroplasty. While the underlying mechanisms are not fully understood, mechanical factors are widely reported to play a key role in glenoid component loosening. In this study, mechanical testing coupled with micro X-ray computed tomography (micro-CT) is performed to apply various physiologically realistic loads on a native and implanted glenoid. Digital volume correlation of micro-CT images is used to compute the 3D full-field deformation and strain inside the glenoid. The measured strain distributions are in good agreement with the analytical solutions of beam bending models, especially for anteriorly and posteriorly eccentric loadings. The effective moduli of the overall native and implanted glenoid were similar. However, under the same eccentric loading conditions, implanted glenoid exhibited a wider range of strain, because the placement of glenoid component increases the bending moment inside the glenoid. This proof-of-concept study provides a feasible and powerful method for the study of 3D full-field biomechanics in native and implanted glenoids.
... All the measurements were taken at the end range with no overpressure. The effect of gravity on the arm was allowed to move the GHJ to the end of passive range for low flexion (LF), [13,19,23] IR with shoulder in extension (EIR), [14,24] IR, and external rotation (ER) while the examiner moved the joint to the end of the passive ROM for horizontal adduction (HAD). For IR, ER, LF, and EIR, the moving arm of the goniometer was aligned with the radial styloid. ...
... LF [19] and EIR [14,23,24] have been reported as the measures of posterior GHJ capsule and posterior rotator cuff extensibility, respectively. The ROM in these measurements was unchanged between pre-and post-pitching conditions. ...
... LF has been shown to change in response to posterior capsule length and EIR in response to external rotator extensibility. [14,23] Capsular adaptations happen over extended periods of repeated overloading, and only one bout of softball pitching probably did not induce any posterior capsule length changes. As for EIR, the ER force production in this study was reduced only by 19% compared to 42% for horizontal abduction. ...
BACKGROUND: The effects of baseball pitching on the glenohumeral joint (GHJ) range of motion (ROM) have been widely studied. Specifically, internal rotation (IR) ROM reduction of the pitching arm, an adaptation to repeated overhead throwing, is linked to increased risk of injuries in baseball pitchers. However, there is a lack of literature on the effects of softball pitching on the GHJ ROM. HYPOTHESIS: Softball pitching to fatigue will result in significant reduction of GHJ supine IR ROM.
... PCT was estimated with the Low Flexion Test (LFT) ( Fig. 2A). 45 This test is performed with the humerus at 60 • of sagittal plane arm elevation. In this position, the examiner supports the arm and allows glenohumeral IR to reach the end of passive motion and a digital inclinometer measures the angle between the forearm and horizontal. ...
... In this position, the examiner supports the arm and allows glenohumeral IR to reach the end of passive motion and a digital inclinometer measures the angle between the forearm and horizontal. 45 The validity and intrarater reliability of the LFT have been reported as excellent when evaluated on the same day. 45,46 Based on prior analysis that reported a side-to-side difference of 11.8 • and maximum standard error of measurement of 2.84 • , the posterior capsule was considered tight when a decrease of at least 7 • in the LFT was identified compared with the contralateral side. ...
... 45 The validity and intrarater reliability of the LFT have been reported as excellent when evaluated on the same day. 45,46 Based on prior analysis that reported a side-to-side difference of 11.8 • and maximum standard error of measurement of 2.84 • , the posterior capsule was considered tight when a decrease of at least 7 • in the LFT was identified compared with the contralateral side. 46 Participants with symptoms of SIS had to report at least 3 months of symptoms consistent with impingement syndrome. ...
Background:
Posterior capsule tightness (PCT) and shoulder impingement syndrome (SIS) symptoms are both associated with altered shoulder biomechanics and impairments. However, their combined effect on kinematics, pain, range of motion (ROM), strength, and function remain unknown.
Objective:
The purpose of this study was to determine if the combination of PCT and SIS affects scapular and humeral kinematics, glenohumeral joint ROM, glenohumeral joint external rotation strength, pain, and function differently than does either factor (PCT or SIS) alone.
Design:
The design was a cross-sectional group comparison.
Methods:
Participants were placed into 1 of 4 groups based on the presence or absence of SIS and PCT: control group (n = 28), PCT group (n = 27), SIS group (n = 25), and SIS + PCT group (n = 25). Scapular kinematics and humeral translations were quantified with an electromagnetic motion capture system. Shoulder internal rotation and external rotation ROM, external rotation strength, and pain and Shoulder Pain and Disabilities Index scores were compared between groups with ANOVA.
Results:
The SIS group had greater scapular internal rotation (mean difference = 5.13°; 95% confidence interval [CI] = 1.53°-8.9°) and less humeral anterior translation (1.71 mm; 95% CI = 0.53-2.9 mm) than the other groups. Groups without PCT had greater internal rotation ROM (16.05°; 95% CI = 5.09°-28.28°). The SIS + PCT group had lower pain thresholds at the levator scapulae muscle (108.02 kPa; 95% CI = 30.15-185.88 kPa) and the highest Shoulder Pain and Disabilities Index score (∼ 44.52; 95% CI = 33.41-55.63).
Limitations:
These results may be limited to individuals with impingement symptoms and cannot be generalized to other shoulder conditions.
Conclusions:
Decreased ROM and lower pain thresholds were found in individuals with both impingement symptoms and PCT. However, the combination of factors did not influence scapular and humeral kinematics.
