Ultrasound verification of palpation-based dry needling techniques of rotator cuff muscles: a prospective feasibility trial.

OBJECTIVES: The primary purpose of this study is to investigate the feasibility of using ultrasound to verify the placement of narrow-gauge dry needles within the supraspinatus and infraspinatus muscles utilizing palpation-based dry needle techniques. METHODS: This is a prospective observational study with 10 participants recruited. Each participant had a dry needle placed within the infraspinatus and supraspinatus muscles by a trained physical therapist utilizing palpation-based methods. Following needle placement, ultrasound examination was then performed to determine the feasibility of needle tip visualization within the targeted tissues. RESULTS: The needle tip was successfully visualized on ultrasound in 19/20 cases. The needle tip accurately resided in the targeted muscle tissue in each of the 19 cases it was successfully visualized. CONCLUSIONS: Narrow-gauge dry needles used in physical therapy practice can be consistently visualized in the supraspinatus and infraspinatus muscles using ultrasound imaging. Also, the palpation method utilized is an accurate means of guiding dry needles into the targeted rotator cuff muscles. These are significant findings because most physical therapy clinics do not have the benefit of real-time imaging guidance and must rely solely on palpation-based needling methods.

Reproducibility of subscapularis muscle thickness measurement using ultrasound imaging. -Relationship between subscapularis muscle thickness and internal rotation torque of the shoulder joint.

BACKGROUND: Few studies have reported on the morphometry of the subscapularis muscle using ultrasound imaging (USI); and their reproducibility has not been verified. OBJECTIVES: This study aimed to clarify the relative and absolute reproducibility of USI measurements of subscapularis muscle thickness at rest and during isometric contraction as well as the degree of change in muscle thickness caused by the amount of internal rotational torque in the shoulder joint. DESIGN: Two-group repeated-measures study. METHODS: The subjects were the inferior fibers of the subscapularis muscle of 40 healthy adult males. Muscle thickness was measured at rest and at 10%-30% of the maximum isometric internal rotation torque. Intraclass correlation coefficients (ICC) and Brand Altman analysis were used for reproducibility measurement. The degree of change in muscle thickness at each torque was also calculated. RESULTS: Intra- and inter-rater ICCs (ranged from 0.69 to 0.91) were good. A proportional error was observed in intra-rater measurements. Both minimal detectable change 95 (ranged from 2.33 to 6.47) were high. The subscapularis muscle thickness was significantly increased at 10% torque (25.49 ± 3.80 mm), 20% torque (26.07 ± 3.90 mm), and 30% torque (25.96 ± 3.82 mm) as compared to that in resting conditions (24.53 ± 4.46 mm) (p < 0.05). CONCLUSION: The reproducibility and error of the subscapularis muscle thickness measurement using USI used in this study were clarified when repeated measurements were made in the same limb position and under the same probe installation conditions, suggesting that the contraction of the subscapularis muscle can be estimated by muscle thickness measurement.

The Effect of Shoulder Mobilization on Scapular and Shoulder Muscle Activity During Resisted Shoulder Abduction: A Crossover Study of Asymptomatic Individuals.

OBJECTIVE: The primary aim was to investigate the effect of inferior shoulder mobilization on scapular and shoulder muscle activity during resisted shoulder abduction in asymptomatic individuals. METHODS: This was a lab-based, repeated-measures, crossover, randomized controlled study. Twenty-two participants were recruited. The order of experimental conditions was randomized. Each participant performed 5 repetitions of resisted shoulder abduction before and after the control and mobilization (grade +IV inferior shoulder mobilization, 3 sets, 60 seconds) conditions. Surface electromyography recorded the muscle activity of anterior, middle, and posterior deltoid; supraspinatus; infraspinatus; upper and lower trapezius; serratus anterior; and latissimus dorsi muscles. RESULTS: Muscle activity levels reduced for infraspinatus (11.3% MVIC, 95% CI: 1.7-20.8), middle (22.4% MVIC, 95% CI: 15.9-28.8) and posterior deltoid (8.7 % MVIC, 95% CI: 4.6-12.9), and serratus anterior (-28.1% MVIC, 95% CI: 15.6-40.8) muscles after the mobilization condition during the eccentric phase of shoulder abduction. No carryover effects were observed, and within-session reliability was excellent (intraclass correlation coefficient scores ranging from 0.94 to 0.99). CONCLUSION: Our findings suggest that inferior glenohumeral mobilization reduces activity levels of some scapular and shoulder muscles. Given the exploratory nature of our study, changes in muscle activity levels may have been found by chance. Confirmatory studies are required.

Effects of kinesiology taping on shoulder girdle muscle activity and sports performance during badminton forehand overhead strokes in amateur badminton players with shoulder impingement syndrome.

BACKGROUND: This study aimed to examine the influence of kinesiology taping (KT), various overhead stroke techniques, and their interactions on shoulder girdle muscle activity and on sports performance in badminton players with shoulder impingement syndrome. METHODS: Twenty-five amateur badminton players with shoulder impingement syndrome participated in the study. Each was exposed to two KT conditions (no taping and taping) while performing four badminton strokes (defensive clear, attacking clear, smash, and drop shot) in a random order. Surface electromyography (EMG) was used to evaluate the activity of the pectoralis major, anterior deltoid, infraspinatus, and latissimus dorsi muscles. The EMG data are expressed as a percentage of the EMG amplitude recorded during a maximal voluntary isometric contraction of the respective muscles. The shuttlecock speed was also measured via video analysis. RESULTS: The pectoralis major, anterior deltoid, infraspinatus, and latissimus dorsi EMG amplitudes were greatest during smashes (P<0.05), followed in general by attacking clearances (P<0.05) and defensive clearances (P<0.05). Drop shots induced the lowest EMG amplitudes in the shoulder girdle muscles (P<0.05). No significant main effect of the KT condition or KT-badminton stroke interaction effects were found (P>0.05). CONCLUSIONS: The use of KT conferred no immediate benefits in improving shoulder girdle muscle activity or sports performance in amateur badminton players with shoulder impingement syndrome. Shoulder girdle muscle activity and sports performance were primarily influenced by the badminton overhead stroke techniques.

Isokinetic assessment of shoulder complex strength in adolescent elite synchronized swimmers.

Children and adolescent participation in sport has increased in recent years. Synchronized swimming requires correct muscle balance in the shoulder complex. The purpose of this study was to establish isokinetic strength profiles and peak torque ratios of shoulder internal and external rotator muscles in a female high-level synchronized swimming team. Twenty-six adolescent female high-level synchronized swimmers, aged 12-14, participated in this study. Maximal bilateral shoulder concentric external and internal rotation force was measured at 60°/s (5 repetitions) and 180°/s (15 repetitions). The isokinetic concentric strength generated by the internal rotator muscles was significantly higher (p < 0.05) than by the external rotators in both limbs and at both velocities. Significant bilateral differences in the external rotation (ER):internal rotation (IR) strength ratio were noted at 60°/s. Isokinetic assessment is essential in sports medicine, since it is the only test capable of diagnosing any shoulder strength deficit.

The effects of pressure biofeedback training on infraspinatus muscle activity and muscle thickness.

The aim of this study was to investigate muscle activity in the infraspinatus and posterior deltoid and infraspinatus muscle thickness during a prone external rotation (PER) exercise using pressure biofeedback. Fifteen healthy men participated in this study, performing PER exercise with pressure biofeedback under four conditions (comfortable, 2 mm Hg, 4 mm Hg, and 8 mm Hg). Surface electromyography (EMG) was used to monitor infraspinatus and posterior deltoid muscle activity, and ultrasonography was used to collect infraspinatus muscle thickness data. Infraspinatus activity and muscle thickness were greatest at 2 mm Hg pressure feedback, and both measures were significantly different from those under other pressure feedback conditions (p < 0.05). In contrast, posterior deltoid activity was lower at 2 mm Hg. However, there was no significant difference between any of the four pressure feedback conditions. These findings suggest that PER exercise with pressure biofeedback, particularly at 2 mm Hg, is effective in selectively activating the infraspinatus muscle.

The effects of preventive rubber band training on shoulder joint imbalance and throwing performance in handball players: A randomized and prospective study.

OBJECTIVES: To investigate the effects of a strength training program (STP) using rubber band exercises. METHODS: Twenty-five athletes were divided into two groups: muscular imbalance in the dominant (D) and in the non-dominant (ND) upper limbs. Each group was subdivided into experimental and control groups. Experimental groups performed eighteen sessions of STP. Athletes were submitted to ball throwing and isokinetic strength tests to assess the muscular strength of the shoulder rotator muscles and conventional and functional balance ratios. RESULTS: STP improved external rotator peak torque (18.0 ± 0.8 to 21.3 ± 1.0 Nm, p < 0.01) and total work (29.3 ± 0.9 to 34.5 ± 1.5 J, p < 0.01) in the D experimental group, while only total work (34.8 ± 2.5 to 37.6 ± 3.1 J, p < 0.03) improved in the D control group. The ND experimental group also presented significant improvement in external rotator peak torque (18.8 ± 0.8 to 21.1 ± 1.3 Nm, p < 0.01) and total work values (29.0 ± 1.4 to 34.6 to 1.6 J, p < 0.01) while there was no strength improvement in the ND control group. The ND experimental group showed an improvement in conventional (61.5 ± 3.5 to 72.7 ± 3.0%, p = 0.03) and functional (1.0 ± 0.1 to 1.6 ± 0.08, p < 0.01) ratios. STP did not improve the conventional ratio in the D experimental group. However, STP produced a large effect size. The D experimental group presented an improvement in ball velocity (49.0 ± 2.4 to 52.5 ± 2.2 km/h, p = 0.04) in standing position throwing. CONCLUSIONS: STP improves muscular strength of external rotator muscles and muscular balance.

Rehabilitative ultrasound imaging of the supraspinatus muscle: Intra- and interrater reliability of thickness and cross-sectional area.

OBJECTIVE: To examine intra- and interrater reliability of thickness and cross-sectional area (CSA) measurements of the supraspinatus muscle using rehabilitative ultrasound imaging (RUSI). METHODS: Two physical therapists acquired b-mode images of the supraspinatus muscles in twenty-five healthy subjects. Thickness and CSA were measured. Intra- and interrater reliability were examined. RESULTS: Intrarater reliability for thickness was high, (ICC1.1 0.91) for rater 1 and (ICC1.1 0.92) for rater 2. Intrarater reliability for CSA was also high, (ICC1.1 0.90) for rater 1 and (ICC1.1 0.85) for rater 2. Interrater reliability for the thickness was high, (ICC3.1 0.86). For CSA, interrater reliability was moderate, (ICC3.1 0.70). CONCLUSION: Supraspinatus muscle thickness and CSA can be reliably measured by physical therapists in healthy subjects. These findings confirm that RUSI has an interesting potential for physiotherapy clinical practice, especially to assess morphometric changes in skeletal muscles. Further research is needed in subjects with shoulder disorders.

Biological strategies to enhance rotator cuff healing.

Rotator cuff tear causes a high rate of morbidity. After surgical repair, the presence of a scar tissue reduces tendon biomechanical properties. Emerging strategies for enhancing tendon healing are growth factors, cytokines, gene therapy and tissue engineering. However their efficacy has to be proved. Growth factors help the process of tendon healing by aiding cells chemotaxis, differentiation and proliferation. Numerous growth factors, including the bone morphogenetic proteins and platelet-derived growth factor can be found during the early healing process of a rotator cuff repair. Growth factors are delivered to the repair site using tissue-engineered scaffolding, coated sutures, or dissolved in a fibrin sealant. Platelet-rich plasma is an autologous concentration of platelets and contains an high density of growth factors. There is some evidence that platelet-rich plasma may improve pain and recovery of function in a short time period, but it does not improve healing rates in rotator cuff. Thus the routine use of platelet-rich plasma in rotator cuff repair is not recommended. The addition of mesenchymal stem cells to scaffolds can lead to the production of a better quality healing tissue. Gene therapy is a gene transfer from a cell into another, in order to over-express the gene required. In this way, cultures of stem cells can over-express growth factors. Better understanding of the mechanisms of physiological tendon healing can promote the correct use of these new biological therapies for a better healing tissue.

The effects of fibroblast growth factor-2 on rotator cuff reconstruction with acellular dermal matrix grafts.

PURPOSE: Our purpose was to determine whether the local application of fibroblast growth factor (FGF) 2 accelerates regeneration and remodeling of rotator cuff tendon defects reconstructed with acellular dermal matrix (ADM) grafts in rats. METHODS: Thirty adult male Sprague-Dawley rats were divided into equal groups undergoing FGF-treated and FGF-untreated repairs. All rats underwent placement of an ADM graft for the supraspinatus defect (3 x 5 mm). FGF-2 (100 microg/kg) in a fibrin sealant was applied to both shoulders in the FGF-treated group, whereas only fibrin sealant was applied in untreated group. At 2, 6, and 12 weeks after surgery, 5 rats (10 shoulders) in each group were sacrificed for histologic analysis (3 shoulders) and biomechanical testing (7 shoulders). The controls were 5 unoperated rats (3 histologic and 7 biomechanical control specimens). RESULTS: Unoperated control tendons inserted into the bone by direct insertion; there was a zone of fibrocartilage between the tendon and bone. At 2 weeks, the FGF-treated group had tendon maturing scores similar to those in the untreated group (P > .05). At 6 and 12 weeks, the FGF-treated group had significantly higher scores (P < .05). At 2 weeks, specimens in both the treated and untreated groups exhibited similar strength; the ultimate tensile failure load was 6.0 +/- 4.0 N and 5.8 +/- 2.0 N, respectively (P > .05). At 6 weeks, the FGF-treated specimens were stronger, with an ultimate tensile failure load of 10.2 +/- 3.1 N compared with 7.2 +/- 2.2 N in the untreated group (P = .02). At 12 weeks, the FGF-treated specimens were stronger, with an ultimate tensile failure load of 15.9 +/- 1.6 N compared with 13.2 +/- 2.0 N in the untreated group (P = .0072), and there were no significant differences in strength compared with the controls (17.8 +/- 2.6 N) (P > .05). CONCLUSIONS: The remodeling of ADM grafts placed in rat rotator cuff tendon defects was accelerated by the local administration of FGF-2. CLINICAL RELEVANCE: The application of FGF-2 may result in improved histologic characteristics and biomechanical strength in ADM graft constructs in humans.

The effect of neuromuscular electrical stimulation of the infraspinatus on shoulder external rotation force production after rotator cuff repair surgery.

BACKGROUND: Muscle weakness, particularly of shoulder external rotation, is common after rotator cuff repair surgery. Neuromuscular electrical stimulation has been shown to be an effective adjunct in the enhancement of muscle recruitment. HYPOTHESIS: Shoulder external rotation peak force can be enhanced by neuromuscular electrical stimulation after rotator cuff repair surgery. STUDY DESIGN: Controlled laboratory study. METHODS: Thirty-nine patients (20 men, 19 women) who had undergone rotator cuff repair surgery were tested a mean of 10.5 days after surgery. Testing consisted of placing patients supine with the shoulder in 45 degrees of abduction, neutral rotation, and 15 degrees of horizontal adduction. Neuromuscular electrical stimulation was applied to the infraspinatus muscle belly and inferior to the spine of the scapula. Placement was confirmed by palpating the muscle during a resisted isometric contraction of the external rotators. Patients performed 3 isometric shoulder external rotation contractions with and without neuromuscular electrical stimulation, each with a 5-second hold against a handheld dynamometer. Neuromuscular electrical stimulation was applied at maximal intensity within comfort at 50 pulses per second, symmetrical waveform, and a 1-second ramp time. The 3 trials under each condition were recorded, and an average was taken. The order of testing was randomized for each patient tested. A paired samples t test was used to determine significant differences between conditions (P < .05). Each group was also divided based on age, rotator cuff tear size, number of days postoperative, and neuromuscular electrical stimulation intensity. Analysis of variance models were used to determine the influence of these variables on external rotation force production (P < .05). RESULTS: Peak force production was significantly greater (P < .001) when tested with neuromuscular electrical stimulation (3.75 kg) as opposed to without neuromuscular electrical stimulation (3.08 kg) for all groups tested. There was no significant difference based on the size of the tear, age of the patient, number of days after surgery, or level of neuromuscular electrical stimulation intensity. CONCLUSION: Peak shoulder external rotation force was significantly increased by 22% when tested with neuromuscular electrical stimulation after rotator cuff repair surgery. Neuromuscular electrical stimulation significantly increased force production regardless of the age of the patient, size of the tear, intensity of the current, or the number of days postoperative. CLINICAL RELEVANCE: Neuromuscular electrical stimulation may be used concomitantly with exercises to enhance the amount of force production and potentially minimize the inhibition of the rotator cuff after repair surgery.

The effects of proprioceptive neuromuscular facilitation stretching on shoulder range of motion in overhand athletes.

AIM: The purpose of this study was to compare the effects of the contract-relax-contract (CRC) and hold-relax-contract (HRC) proprioceptive neuromuscular facilitation (PNF) stretching programs against a control, on external range of motion (ROM) of the shoulder in apparently healthy athletes. METHODS: The subjects were male and female adults between the ages of 25 to 50 years old. Subjects also had been involved in at least one overhand throwing sport (tennis, baseball, quarterback in football, etc.) in the past year. There were 30 participants whom were randomly assigned to 1 of 3 groups (CRC PNF, HRC PNF, control) with 10 subjects per group. Measurement of ROM for external rotation of the shoulder was performed prior to and after 6 weeks of training using a goniometer. The CRC and HRC PNF stretches were performed on subjects twice a week for 6 weeks. The statistical analysis conducted involved a 3x2 analysis of variance with the criteria for statistical significance set at p<0.05. Post hoc testing included paired t-tests and Tukey tests to pinpoint significant differences relative to the interaction between group and time. RESULTS: There was an increase in ROM from pretest to post-test for the HRC group (+13.50 degrees) and CRC group (+14.60 degrees), but not in the control group (+0.30 degrees). The improvement in ROM however, was similar between the HRC and CRC groups. CONCLUSIONS: The CRC and HRC PNF stretching techniques are effective at increasing external shoulder ROM when consistently performed 2 times a week for 6 weeks.

Biologic tendon fixation to metallic implant augmented with autogenous cancellous bone graft and bone marrow in a canine model.

Soft tissue attachment to a metallic prosthesis is required for the improvement of the functional outcome of endoprosthetic reconstructions. Direct tendon attachment to the metallic surface can be achieved through fibrous ingrowth, but such an attachment has a mechanical strength less than one fifth of that of a normal tendon insertion. Regeneration of a transitional structure between the tendon and the metallic surface similar to the normal morphology of a direct tendon insertion may improve the mechanical strength of the new tendon insertion. The objective of the study was to investigate the effect of placement of an interpositional autogenous cancellous bone plate augmented with bone marrow on the mechanical strength of the soft tissue attachment to the metallic surface. The insertion of the supraspinatus tendon was reattached to a porous titanium prosthesis in a canine shoulder model. An autogenous cancellous bone plate supplemented with bone marrow was positioned between the metallic surface and the tendon. Assessment of load-bearing, as a measure of functional recovery, and radiological analysis were performed at 3, 6, 9, 12, and 15 weeks. The animals were euthanized 16 weeks after surgery, and the specimens were subjected to tensile mechanical testing (six animals) and microradiographic-histologic evaluation (three animals). Functional analysis showed a 90.3% recovery of preoperative weight-bearing by 16 weeks (p < 0.05). The mineralized area around the prostheses increased by 63% over time (p < 0.05). Tensile stiffness and strength of the reconstruction were 43.6% and 42.8% of the intact tendon insertion values, respectively. These results were higher than in previous experiments using the direct tendon attachment (p < 0.01, p < 0.05, respectively) or the interpositional bone plate without marrow supplementation (p < 0.05, p < 0.05, respectively). Morphologically, the tendon reattachment site contained the basic tissue transition zones in normal tendon insertion to bone. Inductive bone grafting, supplemented with bone marrow, in the biologic augmentation of tendon anchoring onto a porous metallic prosthesis was an effective technique to increase the mechanical strength of the tendon attachment to the metallic prosthesis.

Kinesiology of the empty can test.

The "empty can test" has been described to isolate supraspinatus muscle activity from the activity of other rotator cuff muscles. The shoulder is positioned in 90 degrees of abduction, with full internal rotation, and 30 degrees of forward flexion and maintained against resistance. The purpose of this study was to determine if the supraspinatus muscle is isolated by the empty can test. Ten normal male subjects were studied (age 25-43/mean 32) with fine-wire electromyography recording from their nondominant arm middle deltoid, supraspinatus, infraspinatus, and teres minor. During the maneuver electromyogram activity was seen not only in the supraspinatus, but also in the infraspinatus and the middle head of the deltoid. Teres minor was inactive throughout the test; however, this is interesting because the teres minor and infraspinatus have previously been described as a functional unit. Our study found that the empty can test does not allow selective activation of the supraspinatus muscle.