Trunk Muscle Function and Core Stability in Women Who Had Muscle-Sparing Pedicled Transverse Rectus Abdominis Myocutaneous Flap Breast Reconstruction.

OBJECTIVE: The long-term effects of the unilateral muscle-sparing pedicled transverse rectus abdominis myocutaneous (TRAMmsp) flap procedure on trunk muscle performances and core stability were investigated in women with breast cancer. METHODS: Forty women (mean age = 42.6 years) who had received breast reconstruction with the unilateral TRAMmsp flap procedure no less than 6 months earlier (mean = 10.3 [standard deviation, SD = 4.9] months) (TRAM group) participated, and 30 women who were healthy and matched for age (mean age = 41.2 years) served as controls (control group). Their abdominal and back muscle strength was assessed using the curl-up and prone extension tests, respectively, and their static abdominal muscle endurance and back extensor endurance were assessed using the sit-up endurance test in the crook-lying position and the Biering-Sørensen test, respectively. Core stability strength was assessed using a 4-level limb-lowering test (abdominal muscle test), and core stability endurance was assessed while lying supine with both flexed legs 1 inch off the mat while keeping the pelvis in a neutral position with a pressure biofeedback unit. RESULTS: Compared with the control group, trunk muscles of the TRAM group were weaker, showing less endurance, as were their core stability strength and endurance. Static trunk muscle endurances and trunk flexion strength were associated with core stability in both groups. CONCLUSIONS: Women exhibit trunk flexor and extensor weakness along with poor endurance and impaired core stability even after an average of 10 months from receiving the TRAMmsp flap procedure. Immobilization after surgery, with possible systemic inflammatory effects from surgery and chemotherapy, might have further contributed to the generalized weakness subsequent to the partial harvesting of the rectus abdominis. IMPACT: Women after breast reconstruction with the TRAMmsp flap procedure show long-lasting deficits of strength and endurance in abdominal muscles, back extensors, and core stability. Proactive measures including early detection and evaluation of impairments as well as timely intervention targeting these clients are important to minimize the dysfunction and support their return to community participation.

Structural and Biomechanical Adaptations to Free-Fall Landing in Hindlimb Cortical Bone of Growing Female Rats.

The purpose of the study was to investigate the adaptation process of hindlimb cortical bone subjected to free-fall landing training. Female Wistar rats (7 weeks old) were randomly assigned to four landing (L) groups and four age-matched control (C) groups (n = 12 per group): L1, L2, L4 L8, C1, C2, C4 and C8. Animals in the L1, L2, L4 and L8 groups were respectively subjected to 1, 2, 4 and 8 weeks of free-fall-landing training (40 cm height, 30 times/day and 5 days/week) while the C1, C2, C4 and C8 groups served as age-matched control groups. The tibiae of the L8 group were higher in cortical bone mineral content (BMC) than those in the C8 group (p < 0.05). Except for the higher bone mineralization over bone surface ratio (MS/BS, %) shown in the tibiae of the L1 group (p < 0.05), dynamic histomorphometry in the tibial and femoral cortical bone showed no difference between landing groups and their age-matched control groups. In the femora, the L1 group was lower than the C1 group in cortical bone area (Ct.Ar) and cortical thickness (Ct.Th) (p < 0.05); however, the L4 group was higher than the C4 group in Ct.Ar and Ct.Th (p <0 .05). In the tibiae, the moment of inertia about the antero-posterior axis (Iap), Ct.Ar and Ct.Th was significantly higher in the L8 group than in the C8 group (p < 0.05). In biomechanical testing, fracture load (FL) of femora was lower in the L1 group than in the C1 group (p < 0.05). Conversely, yield load (YL), FL and yield load energy (YE) of femora, as well as FL of tibiae were all significantly higher in the L8 group than in the C8 group (p < 0.05). Free-fall landing training may initially compromise bone material. However, over time, the current free-fall landing training induced improvements in biomechanical properties and/or the structure of growing bones.

Kinematic Analyses of the Thumb during Simulated Posteroanterior Glide Mobilization.

OBJECTIVE: Thumb problems are common in some health professionals such as physical therapists. The purpose of this case-control study is to investigate the influence of clinical experience and different mobilization techniques on the kinematics of the thumb. METHODS: Twenty-three participants without exposure to manual techniques (the Novice Group) and fifteen physical therapists with at least 3 years of orthopedic experience (the Experienced Group) participated. The kinematics of the thumb while performing 3 different simulated posteroanterior (PA) glide mobilization techniques on a load cell was monitored. These 3 techniques were: 1) unsupported, 2) with digital support and 3) with thumb interphalangeal joint supported by the index finger. The amount of forces exerted were 25% to 100% of maximum effort at 25% increments. The main effects of experience and technique on thumb kinematics were assessed. RESULTS: Both experience and technique had main effects on the flexion/extension angles of the thumb joints. Experienced participants assumed a more flexed position at the carpometacarpal (CMC) joint, and the novice participants performed with angles closer to the neutral position (F = 7.593, p = 0.010). Participants' metacarpophalangeal (MCP) joints were in a more flexed position while performing PA glide with thumb interphalangeal (IP) joint supported by the index as compared to the other two techniques (p < .001). CONCLUSIONS: Negative correlations were generally obtained between the sagittal plane angles of adjacent thumb joints during mobilization/manipulation. Therapists are recommended to treat patient with more stable PA glide mobilization techniques, such as PA glide with thumb interphalangeal joint supported by the index finger, to prevent potential mobilization-related thumb disorders.

Electromyography of symmetrical trunk movements and trunk position sense in chronic stroke patients.

[Purpose] To explore the differences in bilateral trunk muscle activation between chronic stroke patients and healthy controls, this study investigated the symmetry index and cross-correlation of trunk muscles during trunk flexion and extension movements. This study also assessed the differences in trunk reposition error between groups and the association between trunk reposition error and bilateral trunk muscle activation. [Subjects and Methods] Fifteen stroke patients and 15 age- and gender-matched healthy subjects participated. Bilateral trunk muscle activations were collected by electromyography during trunk flexion and extension. Trunk reposition errors in trunk flexion and extension directions were recorded by a Qualisys motion capture system. [Results] Compared with the healthy controls, the stroke patients presented lower symmetrical muscle activation of the bilateral internal oblique and lower cross-correlation of abdominal muscles during trunk flexion, and lower symmetry index and cross-correlation of erector spinae in trunk extension. They also showed a larger trunk extension reposition error. A smaller trunk reposition error was associated with higher cross-correlation of bilateral trunk muscles during trunk movements in all subjects. [Conclusion] Trunk muscle function during symmetrical trunk movements and trunk reposition sense were impaired in the chronic stroke patients, and trunk position sense was associated with trunk muscle functions. Future studies should pay attention to symmetrical trunk movements as well as trunk extension position sense for patients with chronic stroke.

Relationship between trunk stability during voluntary limb and trunk movements and clinical measurements of patients with chronic stroke.

[Purpose] The purposes of this study were to investigate differences between patients with chronic stroke and age matched healthy controls in trunk stability, by assessing the kinematics of the center of mass and moving body segments during voluntary limb and trunk movement, and the relationship between trunk stability and clinical measurements. [Subjects and Methods] Fifteen stroke patients and 15 age- and gender-matched healthy subjects participated. Each subject performed flexion of the hip and shoulder of the non-paretic or matched side as fast as possible, as well as trunk flexion and extension at a self-selected speed. A Qualisys motion system was employed to track the kinematics of the trunk and limbs. [Results] Patients presented larger mediolateral displacement of the center of mass during all limb and trunk movements, and larger velocity of center of mass during hip flexion movement. Healthy subjects showed greater movement velocity during shoulder flexion, trunk flexion and extension. Patients' clinical measurements only correlated with movement characteristics during voluntary trunk motions. [Conclusion] Trunk stability in patients with chronic stroke was compromised during voluntary trunk as well as non-paretic limb movements, and the voluntary trunk movements reflected the trunk deficits measured using clinical measurements. Rehabilitation of patients with chronic stroke should include programs to improve trunk stability.

Effects of methionine restriction and endurance exercise on bones of ovariectomized rats: a study of histomorphometry, densitometry, and biomechanical properties.

To investigate the effects of dietary methionine restriction (MetR) and endurance exercise on bone quality under a condition of estrogen deficiency, female Sprague-Dawley rats (36-wk-old) were assigned to a sham surgery group or one of five ovariectomized groups subjected to interventions of no treatment (Ovx), endurance exercise (Exe), methionine restriction (MetR), methionine restriction plus endurance exercise (MetR + Exe), and estrogen treatment (Est). Rats in the exercise groups were subjected to a treadmill running regimen. MetR and control diets contained 0.172 and 0.86% methionine, respectively. After the 12-wk intervention, all animals were killed, and serum and bone tissues were collected for analyses. Compared with estrogen treatment, MetR diet and endurance exercise showed better or equivalent efficiency in reducing body weight gain caused by ovariectomy (P < 0.05). Whereas only the Est group showed evidence for reduced bone turnover compared with the Ovx group, MetR diet and/or endurance exercise demonstrated efficiencies in downregulating serum insulin, leptin, triglyceride, and thiobarbituric acid reactive substances (P < 0.05). Both the Exe and MetR groups showed higher femoral cortical and total volumetric bone mineral density (vBMD), but only the Exe and Est groups preserved cancellous bone volume and/or vBMD of distal femora (P < 0.05) compared with the Ovx group. After being normalized to body mass, femora of the MetR and MetR + Exe groups had relatively higher bending strength and dimension values followed by the Sham, Exe, and Est groups (P < 0.05). In conclusion, both MetR diet and endurance exercise improved cortical bone properties, but only endurance exercise preserved cancellous bone under estrogen deficiency.

Effect of prior experience and task stability on the intrinsic muscle activity of the thumb.

Manual techniques involving the use of the thumb are commonly employed by physical therapists for treating patients with vertebral disorders. The demands on the intrinsic muscles of the thumb in these manual tasks are very different from those of the pinch tasks. The aim of this study was to investigate the influence of clinical experience and different mobilization techniques on the electromyographic activity (EMG) of thumb intrinsic muscles. Fifteen participants without exposure to manual techniques (the Novice Group) and fifteen physical therapists with at least 3 years of orthopaedic experience (the Experienced Group) participated. Each participant exerted thumb tip forces with 3 different posterioanterior (PA) glide techniques including unsupported, with digital support and with thumb interphalangeal joint supported by the index finger. The exerted force was increased from 25% to 100% maximum force at 25% increments on a 6 component load cell. The thumb tip force and EMG activity of four intrinsic muscles (flexor pollicis brevis, adductor pollicis, abductor pollicis brevis, first dorsal interosseus) were recorded with surface electrodes. Both experience and technique influenced intrinsic muscle activity of the thumb. While participants of both groups generated the same magnitude of force, experienced participants generated less intrinsic muscle activity while performing PA glide through practice. However, novice participants increased activity of the intrinsic muscles in accordance with the stability status of the technique. PA glide with thumb interphalangeal joint supported by the index finger was a more stable technique as evidenced by smallest relative errors of thumb tip force.

Ultrasound imaging evaluation of abdominal muscles after breast reconstruction with a unilateral pedicled transverse rectus abdominis myocutaneous flap.

BACKGROUND: A muscle-sparing (MS) procedure using a full-width pedicled transverse rectus abdominis (RA) myocutaneous (TRAM) flap was developed to reduce abdominal morbidities after breast reconstruction. However, the effects of this procedure on the morphology of the remnant RA muscle and other abdominal muscles remain unclear. OBJECTIVE: Ultrasound imaging was used to evaluate the morphology of the remnant RA muscle and other abdominal muscles in women with the MS pedicled TRAM flap procedure. DESIGN: A case-control, cross-sectional design was used. METHODS: Thirty-four women with an MS unilateral pedicled TRAM flap procedure after mastectomy (TRAM group) and 25 women who were healthy and matched for age (control group) participated. The curl-up test measured trunk flexor muscle strength. Ultrasound imaging measured the thickness of all abdominal muscles in all participants and the cross-sectional area of the RA muscle at rest and in an isometric position with the head raised in women in the TRAM group. Acoustic echogenicity and border visibility assessed the tissue composition of the remnant RA muscle. RESULTS: Trunk flexor muscle strength was weaker in the TRAM group than in the control group. Compared with the remnant RA muscle in the contracted state, the remnant RA muscle in the relaxed state was thinner and had a smaller cross-sectional area. The remnant RA muscle in the relaxed state also was thinner, more echoic, and less visible than its contralateral counterpart. No differences in the thickness of the other abdominal muscles were found between the sides. The abdominal muscles in the TRAM group were smaller than those in the control group. LIMITATION: Because a prospective, longitudinal design was not used, a definite cause-effect relationship could not be determined. CONCLUSIONS: In women with an MS unilateral pedicled TRAM flap procedure, the remnant RA muscle retains its ability to change in size during contraction, albeit at reduced levels. Muscular atrophy occurs in other ipsilateral and contralateral abdominal muscles as well as the remnant RA muscle. Postoperative immobilization is the most likely cause of generalized weakness of the abdominal musculature.

Implementation of a portable electronic system for providing pain relief to patellofemoral pain syndrome patients.

In this study, a portable electromyogram (EMG) system and a stimulator are developed for patellofemoral pain syndrome patients, with the objective of reducing the pain experienced by these patients; the patellar pain is caused by an imbalance between the vastus medialis obliquus (VMO) and the vastus lateralis (VL). The EMG measurement circuit and the electrical stimulation device proposed in this study are specifically designed for the VMO and the VL; they are capable of real-time waveform recording, possess analyzing functions, and can upload their measurement data to a computer for storage and analysis. The system can calculate and record the time difference between the EMGs of the VMO and the VL, as well as the signal strengths of both the EMGs. As soon as the system detects the generation of the EMG of the VL, it quickly calculates and processes the event and stimulates the VMO as feedback through electrical stimulation units, in order to induce its contraction. The system can adjust the signal strength, time length, and the sequence of the electrical stimulation, both manually and automatically. The output waveform of the electrical stimulation circuit is a dual-phase asymmetrical pulse waveform. The primary function of the electrical simulation circuit is to ensure that the muscles contract effectively. The performance of the device can be seen that the width of each pulse is 20-1000 µs, the frequency of each pulse is 10-100 Hz, and current strength is 10-60 mA.

The relationships between inter-recti distance measured by ultrasound imaging and abdominal muscle function in postpartum women: a 6-month follow-up study.

STUDY DESIGN: A prospective longitudinal study. BACKGROUND: Diastasis recti abdominis (DRA) is defined as an increase in the inter-recti distance (IRD), or width of the linea alba. It is a common occurrence in women postpartum. Little information exists on the short- and long-term recovery of IRD and the relationship between changes in IRD and the functional performance of the abdominal muscles. OBJECTIVES: To investigate the natural recovery of IRD and abdominal muscle strength and endurance in women between 7 weeks and 6 months postpartum, and to examine the relationship between IRD and abdominal muscle function. METHODS: Forty postpartum (25-37 years of age) and 20 age-matched, nulliparous females participated. IRD was measured at 4 locations (upper and lower margin of the umbilical ring, and 2.5 cm above and below the umbilical ring) with a 7.5-MHz linear ultrasound transducer. Trunk flexion and rotation strength and endurance were measured with manual muscle testing and curl-ups. Evaluation was conducted at 4 to 8 weeks and 6 to 8 months after childbirth in postpartum women, and only once for the nulliparous female controls. RESULTS: During follow-up, the IRD at 2.5 cm above the umbilical ring and at the upper margin of the umbilical ring decreased (P = .013 and P = .002, respectively). The strength and static endurance of the abdominal muscles improved over time (P<.05). A negative correlation between IRD and abdominal muscle function at 7 weeks and 6 months postpartum was found (r = 0.34 to 0.51; P<.05, except for trunk flexion strength at 6 months postpartum [P = .064]). In addition, IRD changes between 7 weeks and 6 months postpartum were correlated with improvement in trunk flexion strength (Spearman rho = 0.38, P = .040). At 6 months after childbirth, postpartum women had greater mean ? SD IRDs at all 4 locations (from cranial to caudal: 1.80 ± 0.72, 2.13 ± 0.65, 1.81 ± 0.62, and 1.16 ± 0.58 cm) than those of nulliparous females (0.85 ± 0.26, 0.99 ± 0.31, 0.65 ± 0.23, and 0.43 ± 0.17 cm) (all P<.001). All abdominal strength and endurance measurements were less than those of nulliparous females (all P<.001). CONCLUSIONS: The IRD and abdominal muscle function of postpartum women improved but had not returned to normal values at 6 months after childbirth. Future research is essential to explore the need for intervention and, if needed, the effectiveness of specific intervention to reduce the size of IRD in postpartum women.

Biomechanical analysis of axial distraction mobilization of the glenohumeral joint--a cadaver study.

The axial distraction mobilization techniques are frequently employed for treating patients with joint hypomobility. However, there is a lack of basic biomechanical studies and description of this procedure. The purpose of this study was to analyze humeral head displacement while performing an axial distraction mobilization of the glenohumeral joint. Twelve experienced orthopedic physical therapists participated. Distraction mobilization techniques were performed in three different positions of glenohumeral abduction on a fresh cadaveric specimen. Outcome measures were displacements of the humeral head center during distraction mobilization. Result indicated that displacement of the humeral head was largest in the resting position (27.38 mm) followed by the neutral (22.01 mm) and the end range position (9.34 mm). There were significant differences for both the displacement of the humeral head (p<0.002) and the distraction forces used (p<0.015) among the three joint positions. Greater gain in mobility was obtained in distraction at the end range position. In conclusion, during distraction mobilization, the force applied by the therapist and displacement of the humeral head depends on the joint position tested. Our results also provide rationales for choosing end range distraction mobilization for improving joint mobility.

Displacement of the head of humerus while performing "mobilization with movements" in glenohumeral joint: a cadaver study.

The purpose of this study was to compare the displacement of the center of the humeral head (CHH), in a cadaveric glenohumeral joint model, during an experimental abduction simulation with and without the application of a mobilization with movement (MWM) maneuver in an anteroposterior direction. Ten physiotherapists performed passive abduction and a posteriorly directed MWM technique on a fresh cadaveric shoulder joint. The applied forces and joint angles were monitored and displacement of the CHH was calculated. In the abduction only trial, displacement of the humeral head was less than 0.9 mm in posterior, inferior, and lateral directions. During the MWM trial there were significant increases in the displacement of the humeral head posteriorly (7.7 mm), inferiorly (2.7 mm), and laterally (0.5 mm) below 52 degrees of abduction. We suggest that the MWM technique may be effective in changing the joint kinematic characteristics during glenohumeral abduction. This hypothesis, however, would need to be tested in vivo with abduction performed actively.

Effect of general flexibility on thumb-tip force generation - implication for mobilization and manipulation.

Pain involving basal joints of the thumb is one of the major occupation-related disorders for orthopedic physiotherapists and manual therapists. The thumb-tip force generation while performing manual techniques may be influenced not only by the specific manual techniques employed but also by general flexibility of the therapist. The purpose of this study was to investigate the influence of general flexibility and different techniques on thumb-tip force generation. Twenty-three subjects with no exposure to manual techniques and 15 physical therapy clinicians with at least 3 years of orthopedic experience participated. The general flexibility of each subject was assessed by Beighton score (BS). Each subject was requested to exert a maximal force on a six-component load cell with the thumb unsupported (T1), with the rest of digits supported (T2), and with interphalangeal joint of the thumb supported by the index (T3).The thumb-tip force was normalized by body weight. The thumb-tip force generation is influenced not only by the differences in technique employed by the therapists, but also by the general flexibility of the therapists. Physiotherapists with excessive thumb flexibility are advised to perform PA glide with IP joint supported to protect the thumb joints from injury.

Comparison of EMG activity between maximal manual muscle testing and cybex maximal isometric testing of the quadriceps femoris.

Two methods have been used to produce a maximal voluntary isometric contraction (MVIC) of the superficial quadriceps femoris muscles for normalization of electromyographic (EMG) data. The purposes of this study were to compare the myoelectic activity of MVIC of manual muscle testing (MMT) versus Cybex maximal isometric testing. Eighteen normal subjects were recruited. MMT and Cybex testing for MVIC of the dominant leg were performed. EMG activities of the vastus medialis, vastus lateralis and rectus femoris were recorded during MMT and Cybex trials. EMG amplitude and median frequency obtained from the two methods (MMT and Cybex testing) were used for statistical analysis of these three muscles. Statistically, the difference in the mean of the EMG signal amplitude and median frequency between MMT and Cybex testing were not significant. Considering cost and time, MMT for MVIC technique appears to be reliable and highly valuable.

Reliability of stiffness measured in glenohumeral joint and its application to assess the effect of end-range mobilization in subjects with adhesive capsulitis.

End-range mobilization techniques are recommended for the treatment of patients with hypomobile joints. The purposes of this study were (1) to assess the reliability of a glenohumeral (GH) stiffness measurement technique and (2) apply the measurement technique on subjects with adhesive capsulitis to compare the GH end-range stiffness and rotational range of motions (ROMs) before and immediately after the application of end-range translational mobilization techniques. Fifteen normal subjects were recruited for assessment of test-retest reliability. Four men and two women with adhesive capsulitis in the glenohumeral joint (mean disease duration=6.5 months, SD=2.7) were treated with end-range mobilization by an experienced physical therapist. The passive abduction angles, rotational ROM and GH joint stiffness were measured by the same observer before and immediately after end-range mobilization treatment. The test-retest reliability was assessed and revealed good to excellent reliability in anterior-posterior glenohumeral joint stiffness and fair to excellent reliability of GH stiffness in posterior-anterior direction. The GH joint stiffness decreased and passive abduction range of motion increased immediately after end-range mobilization of the shoulder joint. The use of intensive mobilization techniques may help to decrease the risk of further stiffness or joint contracture progression in patients with adhesive capsulitis.

Determining the resting position of the glenohumeral joint in subjects who are healthy.

BACKGROUND AND PURPOSE: The resting position is frequently used by clinicians in the examination and early treatment of patients with joint impairments. However, there is a lack of research on the kinematic characteristics of the resting position of the glenohumeral (GH) joint. The aim of this study was to define the resting position of the GH joint by quantifying the humeral head translation and axial rotational range of motion (ROM). SUBJECTS AND METHODS: The anterior and posterior translation of the humeral head and the rotational ROM of the dominant arm were assessed in the seated position at multiple abduction positions in 15 subjects who were healthy by use of an electromagnetic tracking device. A force of 80 N and a torque of 4 N.m were applied during the measurement procedures for the translation of the humeral head and the rotational ROM, respectively. RESULTS: The mean resting position determined by rotational movement was located at 49.8 degrees of GH abduction. However, the mean resting position determined by translational movement was located at 23.7 degrees of GH abduction and was significantly lower than the resting position determined by rotational movement (t=5.45, P=.000). DISCUSSION AND CONCLUSION: The mean resting position for rotational movement is consistent with the already accepted range of 30 to 60 degrees for a "loosely packed" position of the GH joint. The mean resting position for translational movement appears to be lower than 30 to 60 degrees. The results of this study suggest that, at least for the GH joint, different resting positions should be assessed with different movement criteria (accessory or physiological movement).

Effectiveness of two forms of feedback on training of a joint mobilization skill by using a joint translation simulator.

BACKGROUND AND PURPOSE: Joint mobilization is a complicated task to learn and to teach and is characterized by great intersubject variability. This study's purpose was to investigate whether quantitatively augmented feedback could enhance the learning of joint mobilization and, more specifically, to compare the effects of training with concurrent or terminal feedback by using a joint translation simulator (JTS). SUBJECTS: Thirty-six undergraduate physical therapist students were randomly assigned to control (no feedback), concurrent feedback, and terminal feedback groups. METHODS: The JTS was designed to simulate tissue resistance based on load-displacement relationships of glenohumeral joint specimens. Subjects applied specific mobilization grades of force on the JTS while quantitative feedback was given to the feedback groups either during a trial (ie, concurrent feedback) or after a trial (ie, terminal feedback). The skill acquisition phase lasted a total of 40 minutes, and a total of 75 repetitions were performed for each grade of each joint model. Pretest and no-feedback retention tests were conducted. RESULTS: During acquisition and retention, both feedback groups performed more accurately than did the control group. No obviously superior performance was shown by the terminal feedback group compared with concurrent feedback group during retention testing. DISCUSSION AND CONCLUSION: Subjects who trained with augmented feedback had less variability, and thus more consistency, than the control group subjects who received no feedback. Augmented feedback provides the student with a reference force and the status of his or her performance. The effectiveness of the JTS feedback compared with no feedback was clearly demonstrated. Skill acquisition in mobilization can be enhanced by either concurrent or terminal feedback.

Immediate effect of thermal capsulorrhaphy on glenohumeral joint mobility.

OBJECTIVES: To evaluate the effects of anterior thermal capsulorrhaphy of the glenohumeral joint by monitoring changes of magnitudes of the anterior and posterior displacements of the humeral head and ranges of motion of abduction and rotation in fresh cadaver shoulders. DESIGN: Single session repeated-measures design. BACKGROUND: Following thermal shrinkage anterior and posterior displacements of the head of humerus were decreased. However, no studies were focused on the ranges of motion of abduction and rotation of the shoulder joint immediately. The mobility of abduction and rotation are also important indexes for glenohumeral function. METHODS AND MEASURES: Nine fresh frozen shoulder specimens were used. The dorsal and ventral displacements of humeral head and ranges of motion of abduction and rotation of glenohumeral joint before and after thermal capsulorrhaphy were performed and monitored. Changes after thermal treatment in these linear and angular displacement variables were calculated as outcome measures. RESULTS: After anterior thermal capsulorrhaphy, significant (P < 0.001) decreases were found in displacements (-1.80 mm in dorsal direction and -1.24 mm in ventral direction), rotation range of motion (-3.93 degrees in lateral rotation and -2.60 degrees in medial rotation), and abduction range of motion (-3.15 degrees ). CONCLUSIONS: The results from cadaveric experiments showed that anterior thermal capsulorrhaphy immediately reduced the dorsal and ventral displacements and ranges of abduction and rotation of glenohumeral joint by a small amount. RELEVANCE: Radiofrequency electrosurgical system combined with arthroscopy has the potential to decrease the translations of the humeral head as well as the rotational range of motion of the glenohumeral joint.

Determining the resting position of the glenohumeral joint: a cadaver study.

STUDY DESIGN: Single-session repeated-measures design. OBJECTIVE: To define the resting position of the glenohumeral joint by investigating the magnitude of the anterior and posterior displacements of the humeral head and medial and lateral rotation ranges of motion (ROMs) of the glenohumeral joint at different abduction angles in cadaver specimens. BACKGROUND AND PURPOSE: The resting position of a joint is the position in the joint's ROM at which the joint capsule has its greatest laxity. It is frequently chosen as the position for assessing and treating joints with dysfunction. However, no study has been conducted to determine the resting position of the glenohumeral joint. METHODS: Seven freshly frozen cadaver shoulder specimens (age at time of death [mean +/- SD] was 66.9 +/- 2.5 years) were studied. Specimens were mounted on a system that uses computer-controlled hydraulics and motors to induce and monitor translation and rotation movements of the glenohumeral joint. The magnitudes of total displacement (DTotal) of the head of the humerus and total ROM (RTotal) of the glenohumeral joint were measured in the plane of the scapula at 0 degrees (neutral), 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction. The resting position was determined as the midpoint of the shared range of the 95% to 99.9% confidence intervals of the predicted abduction position where the peaks of displacement and rotation occurred. RESULTS: The DTotal measurements (mean +/- SD) at 0 degrees, 30 degrees, 40 degrees, 50 degrees, 60 degrees, and the end range of glenohumeral joint abduction were 30.53 +/- 9.35, 44.87 +/- 7.34, 45.35 +/- 8.53, 43.99 +/- 10.02, 39.63 +/- 9.85, and 23.80 +/- 10.42 mm, respectively. The RTotal measurements (mean +/- SD) for the same positions were 67.15 degrees +/- 15.87 degrees, 95.64 degrees +/- 24.26 degrees, 98.88 degrees +/- 29.56 degrees, 97.08 degrees +/- 30.17 degrees, 90.91 degrees +/- 28.73 degrees, and 63.48 degrees +/- 25.93 degrees, respectively. The resting position was located at 39.33 degrees +/- 4.37 degrees of glenohumeral abduction (45.13% +/- 7.58% of the available abduction ROM). The resting position (Y) varied linearly with the maximum available abduction ROM (X) (Y = 0.607X - 13.120, R2 = 0.679, F = 10.61, P = 0.023). There was a main effect of joint position on both displacement (P<0.001) and rotation ROM (P<0.001). CONCLUSION: In the plane of the scapula, the resting position of the glenohumeral joint (angle measured between the scapula and humerus) occurred at 39 degrees of abduction (45% of the maximum available abduction ROM) and varied linearly with the amount of available abduction ROM. This finding suggests that in patients with glenohumeral joint hypomobility the resting position is located closer to neutral and that evaluation and treatment should be initiated accordingly at a smaller angle of abduction than the traditional resting position. Our data were derived from cadaver specimens, therefore, caution should be taken when generalizing the results of the present study to a patient population.

Changes in abduction and rotation range of motion in response to simulated dorsal and ventral translational mobilization of the glenohumeral joint.

BACKGROUND AND PURPOSE: Translational mobilization techniques are frequently used by physical therapists as an intervention for patients with limited ranges of motion (ROMs). However, concrete experimental support for such practice is lacking. The purpose of the study was to evaluate the effect of simulated dorsal and ventral translational mobilization (DTM and VTM) of the glenohumeral joint on abduction and rotational ROMs. METHODS: Fourteen fresh frozen shoulder specimens from 5 men and 3 women (mean age=77.3 years, SD=10.1, range=62-91) were used for this study. Each specimen underwent 5 repetitions of DTM and VTM in the plane of scapula simulated by a material testing system (MTS) in the resting position (40 of abduction in neutral rotation) and at the end range of abduction with 100 N of force. Abduction and rotation were assessed as the main outcome measures before and after each mobilization procedure performed and monitored by the MTS (abduction, 4 N m) and by a servomotor attached to the piston of the actuator of the MTS (medial and lateral rotation, 2 N m). RESULTS: There were increases in abduction ROM for both DTM (mean=2.10 , SD=1.76 ) and VTM (mean=2.06 , SD=1.96 ) at the end-range position. No changes were found in the resting position following the same procedure. Small increases were also found in lateral rotation ROM after VTM in the resting position (mean=0.90 , SD=0.92 , t=3.65, P=.003) and in medial rotation ROM after DTM (mean=0.97 , SD=1.45 , t=2.51, P=.026) at the end range of abduction. DISCUSSION AND CONCLUSION: The results indicate that both DTM and VTM procedures applied at the end range of abduction improved glenohumeral abduction range of motion. Whether these changes would result in improved function could not be determined because of the use of a cadaver model.