Shoulder impingement revisited: advanced concepts of pathomechanics and treatment

Subacromial impingement is a common disorder of the shoulder that is still poorly understood. Knowledge of the pathogenesis of this condition has expanded greatly since it was described by Neer 40 years ago. Research has shown that multiple factors contribute to the development of rotator cuff disease. New investigations are exploring this disorder with input from several scientific disciplines. It is essential that orthopaedic surgeons treating patients with subacromial impingement understand the underlying mechanisms, the new research, and the current trends in management of this disease.

Internal impingement of the shoulder

Internal impingement has been proposed as a cause of dead arm syndrome. Recent information, however, suggests that internal impingement is not pathologic; it is a natural restraint to hyperexternal rotation. The loss of internal impingement is pathologic, allowing hyperexternal rotation with hypertwist and fatigue failure of rotator cuff fibers. The "dead arm" of the throwing athlete may be caused by superior labrum anterior and posterior lesions or by SICK scapula syndrome (scapular dyskinesis). Superior labrum anterior and posterior lesions typically require arthroscopic repair, whereas the scapular dyskinesis can generally be treated with a focused rehabilitation program. Open anterior stabilization surgery should not be used to treat dead arm syndrome.

[Results of the surgical treatment for symptomatic mesoacromion]

OBJECTIVES

Functional results of patients who were operated on for symptomatic meso os acromiale were retrospectively evaluated.

METHODS

The study included six patients (5 females, 1 male; mean age 58.5 years; range 51 to 64 years) who underwent surgical treatment for symptomatic os acromiale following unsuccessful conservative treatment. Internal fixation and bone grafting were performed in all the patients. Evaluations were based on physical assessment, radiographic examination, and the UCLA (University of California at Los Angeles) score. All the patients had symptoms of subacromial impingement accompanied by various degrees of rotator cuff tears. Symptomatic os acromiale was diagnosed by imaging studies and tenderness over the acromion during palpation. In case of suspected stability of the acromion, arthroscopy was performed. Fixation was performed with cannulated screws (n=4) or K-wires (n=2) and a cerclage wire or nonabsorbable sutures. Bone graft was harvested locally. The mean follow-up period was 29 months (range 18 to 35 months).

RESULTS

The mean UCLA score increased from a preoperative 11.8 to postoperative 28.2. Union was achieved in four patients in whom cannulated screws were used. Two patients who were fixed with K-wires remained ununited.

CONCLUSION

It is possible to obtain satisfactory results with cannulated screws which probably enable a more rigid fixation in symptomatic os acromiale. Arthroscopic evaluation may be helpful in deciding whether or not os acromiale is symptomatic.

Clinical evaluation of impingement: what to do and what works

Theories about the etiologies of anterior and lateral shoulder pain have changed greatly since "impingement disease" was first described. It is thought that such pain may be caused by contact between the rotator cuff and the acromion and coracoacromial ligament, but the exact pathophysiology of rotator cuff disease remains unclear. The shoulder is notoriously difficult to examine because of the variability of the physical findings in patients with rotator cuff disease. New concepts of impingement, such as coracoid impingement and internal impingement, have been advanced. Although no test is definitive for all causes of anterior and lateral shoulder pain, as the pathophysiology of these conditions becomes better understood the ability to evaluate them clinically also improves.

Technique for arthroscopic rotator cuff repair

Modern arthroscopic tools and techniques have allowed surgeons to operate on a wide variety of injuries using procedures less invasive than traditional open methods. For shoulder surgery in general, and rotator cuff repairs specifically, methods now yield a similar footprint as open procedures with several advantages, including reduced tissue trauma, postoperative pain, swelling, and concern about the deltoid attachment, which should lead to good outcomes.

Eccentric training in chronic painful impingement syndrome of the shoulder: results of a pilot study

Treatment with painful eccentric muscle training has been demonstrated to give good clinical results in patients with chronic Achilles tendinosis. The pain mechanisms in chronic painful shoulder impingement syndrome have not been scientifically clarified, but the histological changes found in the supraspinatus tendon have similarities with the findings in Achilles tendinosis. In this pilot study, nine patients (five females and four males, mean age 54 years) with a long duration of shoulder pain (mean 41 months), diagnosed as having shoulder impingement syndrome and on the waiting list for surgical treatment (mean 13 months), were included. Patients with arthrosis in the acromio-clavicular joint or with large calcifications causing mechanical impingement during horizontal shoulder abduction were not included. We prospectively studied the effects of a specially designed painful eccentric training programme for the supraspintus and deltoideus muscles (3 x 15 reps, 2 times/day, 7 days/week, for 12 weeks). The patients evaluated the amount of shoulder pain during horizontal shoulder activity on a visual analogue scale (VAS), and satisfaction with treatment. Constant score was assessed. After 12 weeks of treatment, five patients were satisfied with treatment, their mean VAS had decreased (62-18, P<0.05), and their mean Constant score had increased (65-80, P<0.05). At 52-week follow-up, the same five patients were still satisfied (had withdrawn from the waiting list for surgery), and their mean VAS and Constant score were 31 and 81, respectively. Among the satisfied patients, two had a partial suprasinatus tendon rupture, and three had a Type 3 shaped acromion. In conclusion, the material in this study is small and the follow-up is short, but it seems that although there is a long duration of pain, together with bone and tendon abnormalities, painful eccentric supraspinatus and deltoideus training might be effective. The findings motivate further studies.

Scapular involvement in impingement: signs and symptoms

Normal scapular motion is closely integrated with arm motion to provide efficient scapulohumeral rhythm in shoulder function. This rhythm is often disrupted in patients with symptoms and signs of shoulder impingement. A large percentage of patients with shoulder impingement have scapular dyskinesis and alterations in the normal resting position of the scapula or in dynamic scapular motion. Scapular dyskinesis usually manifests as a loss of control in the motions of scapular external rotation and the translation of scapular retraction. This loss of control results in alteration in timing and magnitude of acromial upward rotation, excessive antetilting of the glenoid, and loss of maximal rotator cuff muscle activation capability. These pathophysiologic and pathomechanical alterations cause or increase the dysfunction associated with impingement. Scapular dyskinesis may have proximal or distal causative factors. Proximal factors are mainly associated with muscle factors, and can usually be treated with rehabilitation. Distal factors are mainly caused by internal derangements of joints and frequently require surgical treatment followed by appropriate rehabilitation. Physical examination techniques that specifically evaluate scapular dyskinesis can identify the causative factors and guide treatment and rehabilitation strategies.

Mini-open rotator cuff repair

Open shoulder procedures require a deltoid release for proper exposure. Arthroscopic techniques have progressed so that minimally invasive techniques give similar outcomes as more formal open procedures with less risk of morbidity. Arthroscopically assisted open rotator cuff repair offers advantages over open procedures with some diagnostic and decompression performed with the arthroscope. The mini-open technique has more aspects of a cuff repair performed through the arthroscope leaving a few steps to be done open. The modern use of arthroscopic techniques for minimally invasive rotator cuff surgery coupled with advances in rehabilitation is discussed.

Functional activity characteristics of individuals with shoulder dysfunctions

Shoulder-related dysfunction affects individuals' ability to function independently and thus decreases quality of life. Functional task assessment is a key concern for a clinician in diagnostic assessment, outcome measurement, and planning of treatment programs. The purpose of this study was to test the reliability of the FASTRAK 3-dimensional (3-D) motion analysis and surface electromyography (sEMG) systems to analyze 3-D shoulder complex movements during functional tasks and compare motion patterns between subjects with and without shoulder dysfunctions (SDs).For the test, sEMG and 3-D motion analysis systems were used to characterize the functional tasks. Twenty-five asymptomatic male subjects and 21 male subjects with right shoulder disorders performed four functional tasks which involved arm reaching and raising activities with their dominant arms. Reliability was estimated by the intraclass correlation coefficient (ICC). Motion pattern was compared between two groups using mixed analysis of variances (ANOVAs). Shoulder complex kinematics and associated muscular activities during functional tasks were reliably quantified (ICC=0.83-0.99) from the means of three trials. Relative to the group without SDs, the group with SDs showed significant alteration in shoulder complex kinematics (3 degrees -40 degrees ) and associated muscular activities (3-10% maximum). Scapular tipping, scapular elevation, upper trapezius muscle function, and serratus anterior muscle function may have implications in the rehabilitation of patients with SDs.

Partial-thickness rotator cuff tears

Partial-thickness tears of the rotator cuff have been diagnosed with increased frequency because of a heightened awareness of the condition by clinicians and improved diagnostic methods. Research into the causes, natural history, and optimal treatment of this condition lags behind that of full-thickness tears. However, despite the limitations in the existing literature, there has emerged a consensus among shoulder experts that partial-thickness rotator cuff tears should be aggressively treated in the active athlete because of the unfavorable natural history of these lesions and success of accepted surgical algorithms. This review will provide an overview of the theories regarding the origins of partial-thickness rotator cuff tears, discuss the relative accuracy of accepted diagnostic techniques, and summarize the indications and methods of operative repair with an emphasis on the results of various treatment approaches.

Subacromial impingement syndrome: the role of posture and muscle imbalance

Changes in upper body posture, colloquially termed forward head posture (FHP), are considered to be an etiologic factor in the pathogenesis of subacromial impingement syndrome (SIS). The literature suggests that postural deviations associated with FHP follow distinct patterns involving an increase in the thoracic kyphosis angle and a downwardly rotated, anteriorly tilted, and protracted scapula, which in turn leads to increased compression in the subacromial space. These postural changes are thought to occur concurrently with an imbalance of the musculature, and conservative rehabilitation commonly involves addressing both posture and muscle imbalance. There is a paucity of evidence supporting the hypothesis that posture and muscle imbalance are involved in the etiology of SIS. The purpose of this study was to investigate whether FHP was associated with an increased thoracic kyphosis, an altered position of the scapula; and a reduction in glenohumeral elevation range. Selected sagittal and frontal plane postural measurements were made in 60 asymptomatic subjects and 60 subjects with SIS. The findings suggested that upper body posture does not follow the set patterns described in the literature, and further research is required to determine whether upper body and scapular posture and muscle imbalance are involved in the pathogenesis of SIS.

Contact forces in the subacromial space: effects of scapular orientation

The purpose of this study was to examine the effects of scapular orientation on clearance in the subacromial space. Eight glenohumeral joints from fresh-frozen human cadavers were secured to an Instron mechanical testing machine via a custom-made translation table. Forces were applied to simulate rotator cuff and deltoid contraction. Superior translation of the glenohumeral joint was simulated, and the distance before the development of significant subacromial contact force was measured. Specimens were tested at varying orientations of scapular posterior tilting, upward rotation, and external rotation. Results demonstrated no significant effect of posterior tilting and external rotation. Subacromial clearance was found to decrease with an increase in upward rotation, which is contrary to what was expected. These results suggest that changes in upward rotation observed in patients with impingement syndrome may serve to open the subacromial space. Future work needs to focus on confirming these results and determining contact location.

Exercises versus arthroscopic decompression in patients with subacromial impingement: a randomised, controlled study in 90 cases with a one year follow up

OBJECTIVES

To compare the effect of graded physiotherapeutic training of the rotator cuff versus arthroscopic subacromial decompression in patients with subacromial impingement.

METHODS

Randomised controlled trial with 12 months' follow up in a hospital setting. Ninety consecutive patients aged 18 to 55 years were enrolled. Symptom duration was between six months and three years. All fulfilled a set of diagnostic criteria for rotator cuff disease, including a positive impingement sign. Patients were randomised either to arthroscopic subacromial decompression, or to physiotherapy with exercises aiming at strengthening the stabilisers and decompressors of the shoulder. Outcome was shoulder function as measured by the Constant score and a pain and dysfunction score. "Intention to treat" analysis was used, with comparison of means and control of confounding variables by general equation estimation analysis.

RESULTS

Of 90 patients enrolled, 84 completed follow up (41 in the surgery group, 43 in the training group). The mean Constant score at baseline was 34.8 in the training group and 33.7 in the surgery group. After 12 months the mean scores improved to 57.0 and 52.7, respectively, the difference being non-significant. No group differences in mean pain and dysfunction score improvement were found.

CONCLUSIONS

Surgical treatment of rotator cuff syndrome with subacromial impingement was not superior to physiotherapy with training. Further studies are needed to qualify treatment choice decisions, and it is recommended that samples are stratified according to disability level.

Trapezius muscle imbalance in individuals suffering from frozen shoulder syndrome

This aim of this study was to characterize upper and lower trapezius muscle activity for patients experiencing frozen shoulder syndrome (FSS) compared to asymptomatic subjects. Fifteen patients suffering from unilateral FSS and 15 asymptomatic subjects voluntarily participated in this study. Data were gathered on electromyographic (EMG) activity obtained from the upper and lower trapezius muscles during maximal static arm elevations at six different testing positions: 60 and 120 degrees of flexion, abduction in the frontal plane, and abduction in the scapular plane. The group with FSS revealed increased upper trapezius EMG activity at the 60 degrees (mean difference = 12%, p < 0.003) and 120 degrees (mean difference = 24%, p < 0.004) testing positions, and increased lower trapezius EMG activity at the 120 degrees testing positions (mean difference = 6%, p < 0.002), compared to asymptomatic subjects. Higher ratios of the upper trapezius to lower trapezius EMG activity were also found in the patient group (p < 0.0005) compared to asymptomatic subjects. The results of this study indicate that the increased trapezius muscle activity may contribute to scapular substitution movement in compensation for impaired glenohumeral motion in patients with FSS. The insufficiency of the increased lower trapezius muscle activity should be an important consideration in the rehabilitation of patients experiencing FSS.

Shoulder impingement: the effect of sitting posture on shoulder pain and range of motion

The re-education of spinal posture is an integral part of shoulder impingement management yet supporting evidence is limited. The purpose of this study was to evaluate the effect of slouched versus erect sitting posture on shoulder pain intensity and range of motion (ROM) in subjects with impingement. A same-subject repeated-measures design was utilized. Maximum active shoulder flexion and associated pain intensity were measured in 28 subjects in slouched and erect sitting postures, using video-analysis and visual analogue scales, respectively. An intra-tester reliability study of the video-analysis system was completed and intra-class correlation coefficients calculated. Shoulder flexion differences between slouched and erect sitting posture were analysed using a repeated-measures analysis of variance (ANOVA). The intra-tester reliability of the video-analysis method was found to be 'excellent' (ICC = 0.99). Flexion ROM was significantly greater in the erect sitting posture (F = 100.3, P < 0.0001); the mean ROM difference between postures was 17.67 degrees (+/- 9.17 degrees). There was no significant difference in pain intensity between postures (F = 1.9, P = 0.179). An erect sitting posture appeared to increase active shoulder flexion in subjects with shoulder impingement, although there were no differences in reported pain intensity. Further research is required to investigate the long-term effects of postural re-education.

Diagnosis and relation to general health of shoulder disorders presenting to primary care

OBJECTIVES

To prospectively evaluate the incidence, spectrum of disease and relation to general health of shoulder disorders in primary care.

METHODS

Patients presenting with shoulder pain to two large general practices in the Cambridge area over a 1-month period were invited to participate. After consulting their general practitioner, patients were administered a demographic information questionnaire, a shoulder pain and disability index (SPADI) and a short form 36 (SF-36) health survey. Subsequent review in a clinic held by a rheumatology registrar every 2 weeks was undertaken.

RESULTS

The sex- and age-standardized incidence of shoulder pain was 9.5 per 1000 (95% confidence interval 7.9 to 11.2 per 1000). Rotator cuff tendinopathy was found in 85%, signs of impingement in 74%, acromioclavicular joint disease in 24%, adhesive capsulitis in 15% and referred pain in 7%. On the SPADI the mean disability subscale score was 45 (95% confidence interval 41 to 50) and the mean pain score was 58 (95% confidence interval 53 to 62) (range 0 to 100). Evaluation of general health status using the SF-36 showed the difference between population norms and those with shoulder pain was significant in six of the eight domains, being especially marked (greater than 20 point reduction) for emotional role, physical function and physical role.

CONCLUSION

Shoulder pain, most commonly due to rotator cuff tendinopathy, is associated with significantly reduced health when measured by both specific and generic means. Effort towards prevention and early intervention in these complaints is warranted.

[Arthroscopic evaluation of the mobility of the meso-acromion]

OBJECTIVES

Failure of fusion of the secondary centers of ossification of the acromial apophyses is a pathology that should be included in the differential diagnosis of shoulder pain and subacromial impingement syndrome. Mobility of the meso-acromion is of particular importance in choosing the appropriate treatment. This study presents a new arthroscopic method to evaluate the mobility of os acromiale.

METHODS

We presented the arthroscopic evaluation and surgical treatment of three women (mean age 43.3 years; range 34 to 53 years) with shoulder pain and a radiographically confirmed meso-acromiale. The Neer and Hawkins impingement signs were positive and palpation over the acromion gave rise to pain. Axillary radiographs showed a meso-acromion in all the affected shoulders. Magnetic resonance imaging showed a rotator cuff tear in one patient. During arthroscopic examination the motility of the meso-acromion was dynamically observed in the subacromial region and the rotator cuff tear was repaired. Acromioplasty was not performed. Following removal of pseudarthrotic areas, the mobile meso-acromion was fixed with a cerclage wire, two cannulated screws and bone grafting, followed by a tension-band configuration. The mean follow-up was five years (range 3 to 6 years).

RESULTS

Union occurred in all the patients. None of the patients had shoulder pain at rest or during activities. When compared with the normal side, the range of motion and the strength of the shoulder were normal in all the patients, with Constant scores being 89, 96, and 98, respectively.

CONCLUSION

Identification of the type of os acromiale is important for the treatment plan. The meso-acromion is particularly important because of its greater size and its role in narrowing the subacromial space. It is necessary to determine whether the meso-acromion fragment is mobile. Dynamic arthroscopic examination offers significant help in this respect.

Scapular kinematics during transfers in manual wheelchair users with and without shoulder impingement

BACKGROUND

Scapular function during humeral elevation has been reported in groups with and without shoulder impingement pathology. To date, no one has assessed scapular kinematics during upper extremity loaded tasks that manual wheelchair users must perform on a daily basis. Therefore, the objective of this study was to compare scapular kinematics and muscle activation patterns during two different wheelchair transfers in groups of manual wheelchair users with and without shoulder impingement.

METHODS

A case controlled study of manual wheelchair users, with and without shoulder impingement was performed. Twenty-three male manual wheelchair users (13 without shoulder impingement, 10 with shoulder impingement) performed transfers toward the involved or dominant limb (lead limb transfer) and away from the instrumented limb (trail limb transfer). Position and orientation measures of the thorax, scapula and humerus were obtained using an electromagnetic tracking system. Muscle activity data were collected using telemetered electromyography. Each subject performed three trials of wheelchair transfers to each side.

FINDINGS

Manual wheelchair users with impingement performed transfers with reduced thoracic flexion, increased scapular internal rotation, and increased humeral internal rotation as compared to those without impingement. Differences were found between the tasks in the scapular motions and EMG amplitude. Trail limb transfer presented with reduced scapular upward rotation and posterior tip as compared to the lead limb transfer task. Increased muscle activity for the lower trapezius and serratus anterior muscles was demonstrated in the trail limb transfer.

INTERPRETATION

This study provides the first kinematic description of scapular kinematics during transfer tasks. Shoulder impingement and direction of transfer does affect transfer task performance in manual wheelchair users. Scapular kinematics and muscle patterns during transfers may predispose manual wheelchair users to the development of shoulder pathology.

The impact of rotator cuff pathology on isometric and isokinetic strength, function, and quality of life

The purposes of this study were to determine the reliability of strength and self-reporting measures, the relationship of different strength measures to function, and the impact of rotator cuff pathology on patients' quality of life. Patients with nonoperated rotator cuff pathology (n = 36) and unaffected control subjects (n = 48) were assessed by use of the LIDO dynamometer to determine isometric and isokinetic (concentric and eccentric) strength of the shoulder rotators. The Shoulder Pain and Disability Index and Short Form-36 were self-reported by patients. Intraclass correlation coefficients (ICCs) were used to assess reliability, and Pearson correlations and multiple linear regression were used to determine the relationship between strength and function. The findings of this study include the following: (1) measures of self-reported physical disability had high reliability (ICC = 0.89); (2) the LIDO dynamometer reliably measured internal and external shoulder rotation strength in both concentric and isometric modes of testing (ICC = 0.78-0.94), whereas eccentric muscle actions had lower reliability; (3) all shoulder rotation strength measures were predictive of disability, with isometric external rotation strength being the most predictive (r = 0.56); and (4) the presence of rotator cuff pathology was highly predictive of impaired physical health quality of life (R(2) = 0.71, P < .001).

Scapular rotation in swimmers with and without impingement syndrome: practice effects

PURPOSE

The purpose of this study was to examine the effects of a normal swim practice on the scapular kinematics of swimmers with impingement syndrome and healthy swimmers.

METHODS

Twenty swimmers with no known shoulder pathology and 20 swimmers with shoulder impingement syndrome participated in this study. Shoulder strength measurements were made with a hand-held dynamometer. Static scapular upward rotation was measured with an inclinometer with the arm at rest, and at 45, 90, and 135 degrees of humeral elevation. Measurements were made pre- and postswim training.

RESULTS

There were no differences in baseline measurements of kinematics between the two groups. After swimming, both groups experienced muscle fatigue as indicated by a significant reduction in force generation. Although swimming practice resulted in no significant differences in scapular kinematics for the healthy swimmers, there were significant decreases in scapular upward rotation in subjects with shoulder impingement.

CONCLUSIONS

Abnormal scapular kinematics in swimmers with impingement syndrome may only be observed after an intense swim practice. The examination of swimmers immediately after swimming may provide more information regarding impingement syndrome than a typical clinical exam.

Patterns of motion loss in subjects with idiopathic loss of shoulder range of motion

BACKGROUND

Subjects with idiopathic loss of shoulder motion have difficulty sleeping, performing overhead activities, and completing activities of daily living. Treatment has been variable in approach and success. Cyriax's proposed shoulder capsular pattern was external rotation most limited followed by abduction followed by internal rotation. This investigation was performed to determine if a consistent pattern of motion loss was present in subjects with idiopathic loss of shoulder motion.

METHODS

Repeated measurement of 25 (22 female) subjects' bilateral shoulder patterns of motion were compared. The three-dimensional position of the scapula and humerus throughout active shoulder abduction, external rotation, flexion, internal rotation, and scapular plane abduction was evaluated with an electromagnetic motion capture system. Patterns of motion loss were determined for both shoulders. The proportions of peak shoulder motion to mean maximum non-involved shoulders abduction, external, and internal rotation were utilized to determine the pattern of motion loss.

FINDINGS

There was a significant difference in motion loss patterns between the involved and non-involved shoulders with the arm at the side. The internal rotation less than abduction less than external rotation pattern was demonstrated in 14 of 25 (56%) involved shoulders. No pattern was present in 14 of 21 (67%) non-involved shoulders. With the arm abducted, internal rotation was the most limited motion in 23 of 25 (92%) involved shoulders.

INTERPRETATION

The results did not support Cyriax's proposed glenohumeral capsular pattern. Defining the pattern of motion loss in subjects with idiopathic loss of shoulder motion may assist in diagnosis and treatment.

Shoulder function and 3-dimensional kinematics in people with shoulder impingement syndrome before and after a 6-week exercise program

BACKGROUND AND PURPOSE

Shoulder impingement syndrome is a common condition and is often managed with an exercise program. The purpose of this study was to examine an exercise program in patients with shoulder impingement syndrome. Specifically, the purpose was to identify changes that might occur in 3-dimensional scapular kinematics, physical impairments, and functional limitations.

SUBJECTS

Fifty-nine patients with impingement syndrome were recruited, and 39 patients successfully completed the 6-week rehabilitation program and follow-up testing. Impingement was defined as having at least 3 of 6 predefined clinical signs or symptoms.

METHODS

Subjects were assessed before and after a 6-week rehabilitation program and again at 6 months. Pain, satisfaction, and function were measured using the University of Pennsylvania Shoulder Scale. Range of motion, isometric muscle force, and 3-dimensional scapular kinematic data also were collected. Subjects were given a progressive exercise program that included resistive strengthening, stretching, and postural exercises that were done daily at home. Subjects also were given shoulder education related to anatomy, the basic mechanics of impingement, and strategies for reducing load on the shoulder. Each subject attended one physical therapy session per week for a 6-week period, primarily for monitoring and upgrading the exercise program. Pretest and posttest scores were compared using paired t tests and repeated-measures analysis of variance.

RESULTS

Passive range of motion increased for both external and internal rotation but not for elevation. Abduction external and internal rotation force all increased. There were no differences in scapular kinematics. Improvements were found for pain, satisfaction, and shoulder function and for Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) scores related to physical function. At 6-month follow-up, improvements made in pain, satisfaction, and function were maintained.

DISCUSSION AND CONCLUSION

The use of this exercise protocol in the management of shoulder impingement syndrome may have a positive impact on patients' impairments and functional limitations. Our findings suggest a relatively simple exercise program combined with patient education may be effective and, therefore, merits study in a larger trial using a control group. Changes in scapular kinematics did not appear to be a primary mechanism underlying improvement in symptoms and function.

Acromio-humeral distance variation measured by ultrasonography and its association with the outcome of rehabilitation for shoulder impingement syndrome

OBJECTIVE

First, to validate an ultrasonographic measure of the acromio-humeral distance (AHD); second, to compare the AHD variation during active abduction in patients with shoulder impingement syndrome (SIS) and healthy subjects; and third, to evaluate the relationship between functional status and AHD variations before and after rehabilitation in SIS subjects.

DESIGN

This study has 3 components: (1) a reliability study, (2) a case-control study, and (3) a preliminary pretreatment/posttreatment clinical trial.

SETTING

Primary care hospital setting.

PARTICIPANTS

Seven SIS patients and 13 healthy subjects.

INTERVENTIONS

For the clinical trial, the SIS subjects participated in 12 sessions of a rehabilitation program over 4 weeks.

MAIN OUTCOME MEASURES

First, intraclass correlation coefficient for interobserver reliability; second, AHD measured at 0 degrees, 45 degrees, and 60 degrees of active abduction; and third, Western Ontario Rotator Cuff Index.

RESULTS

Intraclass correlation coefficient for interobserver reliability ranged from 0.86 to 0.92 for the 3 shoulder positions. A significant reduction of the AHD was found within groups between rest and active abduction (P < 0.05). Comparison of AHD between groups was not statistically different (P = 0.06; beta < 0.80). In pre-post rehabilitation analysis, improvement of the Western Ontario Rotator Cuff Index score was positively correlated to the reduction of the AHD narrowing as the arm was abducted (r = 0.86; P = 0.01).

CONCLUSIONS

The ultrasound measure of AHD is reliable and sensitive. Although a distinct pattern of AHD variation in SIS patients could not be confirmed, a strong positive relationship was found between the reduction of AHD narrowing and functional improvement following rehabilitation. Ultrasound measurement of AHD might help identify SIS patients who will benefit from rehabilitation.