Dead men and radiologists don't lie: a review of cadaveric and radiological studies of rotator cuff tear prevalence

Platelet-rich plasma protects tenocytes from adverse side effects of dexamethasone and ciprofloxacin

BACKGROUND

Ruptured tendons heal very slowly and complete recovery from injury is uncertain. Platelet-rich plasma (PRP), a rich source of growth factors, is currently being widely tested as a soft tissue healing agent and may accelerate tendon repair. The authors assessed the ability of PRP to prevent in vitro adverse effects of 2 drugs commonly linked to tendon rupture and tendinopathy, glucocorticoids and fluoroquinolone antibiotics.

HYPOTHESIS

The pro-healing response induced by PRP protects human tenocytes against the cytotoxic effects of dexamethasone and ciprofloxacin.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human primary hamstring tenocytes were exposed to different doses of ciprofloxacin and dexamethasone with and without PRP. AlamarBlue, β-galactosidase assay, and live/dead stain were used to measure, respectively, viability, senescence, and death in tenocyte culture.

RESULTS

The viability of cells exposed to high doses of ciprofloxacin was significantly decreased compared with controls, with no induced senescence but increased cell death. Dexamethasone reduced viable cell number without inducing overt cell death, but the number of senescent cells increased considerably. After co-treatment with 10% PRP, viable cell number increased significantly in both conditions and the number of dead cells decreased in ciprofloxacin-treated cultures. Moreover, dexamethasone-induced senescence was markedly reduced by co-treatment with 10% PRP.

CONCLUSION

This study demonstrates that ciprofloxacin and dexamethasone have differing adverse effects on human tenocytes, with ciprofloxacin inducing cell death while dexamethasone primarily induces senescence. The authors showed that PRP can protect cultured human tenocytes against cell death or senescence induced by these drugs.

CLINICAL RELEVANCE

Both ciprofloxacin and dexamethasone are highly effective in treatment of inflammatory and infectious conditions, therefore new strategies to minimize their adverse effects are of strong interest. These findings suggest the potential for local administration of PRP to enhance tendon healing in patients undergoing glucocorticoid or fluoroquinolone treatment.

The Maastricht Ultrasound Shoulder pain trial (MUST): ultrasound imaging as a diagnostic triage tool to improve management of patients with non-chronic shoulder pain in primary care

Background

Subacromial disorders are considered to be one of the most common pathologies affecting the shoulder. Optimal therapy for shoulder pain (SP) in primary care is yet unknown, since clinical history and physical examination do not provide decisive evidence as to the patho-anatomical origin of the symptoms. Optimal decision strategies can be furthered by applying ultrasound imaging (US), an accurate method in diagnosing SP, demonstrating a clear relationship between diagnosis and available therapies. Yet, the clinical cost-effectiveness of applying US in the management of SP in primary care has not been studied. The aim of this paper is to describe the design and methods of a trial assessing the cost-effectiveness of ultrasound imaging as a diagnostic triage tool to improve management of primary care patients with non-chronic shoulder pain.

Methods/Design

This randomised controlled trial (RCT) will involve 226 adult patients with suspected subacromial disorders recruited by general practitioners. During a Qualification period of two weeks, patients receive care as usual as advised by the Dutch College of General Practitioners, and patients are referred for US. Patients with insufficient improvement qualify for the RCT. These patients are then randomly assigned to the intervention or the control group. The therapies used in both groups are the same (corticosteroid injections, referral to a physiotherapist or orthopedic surgeon) except that therapies used in the intervention group will be tailored based on the US results. Ultrasound diagnosed disorders include tendinopathy, calcific tendinitis, partial and full thickness tears, and subacromial bursitis. The primary outcome is patient-perceived recovery at 52 weeks, using the Global Perceived Effect questionnaire. Secondary outcomes are disease specific and generic quality of life, cost-effectiveness, and the adherence to the initial applied treatment. Outcome measures will be assessed at baseline, 13, 26, 39 and 52 weeks after inclusion. An economic evaluation will be performed from both a health care and societal perspective with a time horizon of 52 weeks.

Discussion

The results of this trial will give unique evidence regarding the cost-effectiveness of US as a diagnostic triage tool in the management of SP in primary care.

A prospective study of shoulder pain in primary care: prevalence of imaged pathology and response to guided diagnostic blocks

BACKGROUND

The prevalence of imaged pathology in primary care has received little attention and the relevance of identified pathology to symptoms remains unclear. This paper reports the prevalence of imaged pathology and the association between pathology and response to diagnostic blocks into the subacromial bursa (SAB), acromioclavicular joint (ACJ) and glenohumeral joint (GHJ).

METHODS

Consecutive patients with shoulder pain recruited from primary care underwent standardised x-ray, diagnostic ultrasound scan and diagnostic injections of local anaesthetic into the SAB and ACJ. Subjects who reported less than 80% reduction in pain following either of these injections were referred for a magnetic resonance arthrogram (MRA) and GHJ diagnostic block. Differences in proportions of positive and negative imaging findings in the anaesthetic response groups were assessed using Fishers test and odds ratios were calculated a for positive anaesthetic response (PAR) to diagnostic blocks.

RESULTS

In the 208 subjects recruited, the rotator cuff and SAB displayed the highest prevalence of pathology on both ultrasound (50% and 31% respectively) and MRA (65% and 76% respectively). The prevalence of PAR following SAB injection was 34% and ACJ injection 14%. Of the 59% reporting a negative anaesthetic response (NAR) for both of these injections, 16% demonstrated a PAR to GHJ injection. A full thickness tear of supraspinatus on ultrasound was associated with PAR to SAB injection (OR 5.02; p < 0.05). Ultrasound evidence of a biceps tendon sheath effusion (OR 8.0; p < 0.01) and an intact rotator cuff (OR 1.3; p < 0.05) were associated with PAR to GHJ injection. No imaging findings were strongly associated with PAR to ACJ injection (p ≤ 0.05).

CONCLUSIONS

Rotator cuff and SAB pathology were the most common findings on ultrasound and MRA. Evidence of a full thickness supraspinatus tear was associated with symptoms arising from the subacromial region, and a biceps tendon sheath effusion and an intact rotator cuff were associated with an intra-articular GHJ pain source. When combined with clinical information, these results may help guide diagnostic decision making in primary care.

Subscapularis tendon integrity: an examination of shoulder index tests

CLINICAL QUESTION

The systematic review focused on various index tests for the shoulder. We concentrated on the subscapularis tendon results to determine the accuracy of reported index tests for clinically diagnosing subscapularis integrity.

DATA SOURCES

Studies were identified by an OVID search using MEDLINE, SPORTDiscus, and CINHAL databases (1966-2006) and a hand search by 2 authors (E.J.H. and S.C.). Primary search terms were shoulder, examination, and diagnosis. In addition to the database searches, personal files were hand searched by one of the authors (E.J.H.) for publications, posters, and abstracts. The reference lists in review articles were cross-checked, and all individual names of each special test were queried using MEDLINE and PubMed.

STUDY SELECTION

The search was limited to English-language journals. Studies were eligible for inclusion if the criterion standard was surgery, magnetic resonance imaging, or injection (subacromial or acromioclavicular joint); at least 1 physical examination test or special test was studied; and one of the paired statistics of sensitivity and specificity was reported or could be determined. Excluded were studies in which the index test was performed under anesthesia or in cadavers, studies in which the index test was assigned the status of composite physical examination, and review articles. Studies were grouped according to the subscapularis index test assessed: lift off, internal-rotation lag sign, Napoleon sign, bear hug, belly off, and belly press.

DATA EXTRACTION

Studies were selected in a 2-stage process. First, all abstracts and articles found through the search process were independently reviewed by 2 authors (E.J.H. and S.C.). Disagreement on inclusion of an article was resolved by consensus. Second, each selected study was assessed by each reviewer independently. A third reviewer made the final decision on any disagreements for the selected studies. The primary outcome measures were sensitivity and specificity and positive and negative likelihood ratios. The quality of a study was determined by assessing its internal and external validity. Validity was determined by the primary author (E.J.H.) using the Quality Assessment of Diagnostic Accuracy Studies (QUADAS) statement. Our work required data extraction from the original articles, which we used to generate 2 x 2 contingency tables for each index test. Pooled indices of clinical usefulness were then determined for each index test.

MAIN RESULTS

The specific search criteria identified 922 articles for review. Of these, 4 met the inclusion and exclusion criteria for subscapularis tendon tears, resulting in the number of studies assessing each index test as follows: 4 for lift off, 2 for internal-rotation lag sign, 2 for Napoleon sign, 1 for bear hug, 1 for belly off, and 1 for belly press. Subscapularis tears were identified by the criterion standard of surgery to visually assess the torn fibers. Across all 4 studies, a total of 304 shoulders were examined, 95 of which had a subscapularis tear (45 full thickness, 50 partial thickness), and 106 were injury free. Indices of clinical usefulness for full-thickness and partial-thickness subscapularis tears are reported in Tables 1 and 2 , respectively.

Relationship between self-reported shoulder function/quality of life, body mass index, and other contributing factors in patients awaiting rotator cuff repair surgery

HYPOTHESES

We hypothesized that body mass index (BMI) would be negatively associated with self-reported shoulder function/pain. A second objective was to investigate the significance of other potential contributing factors: age, sex, smoking status, tear size, and workers' compensation (WC) involvement.

METHODS

In this retrospective cohort study, consecutive patients who underwent arthroscopic rotator cuff repair surgery between 2002 and 2007 were reviewed. Preoperative American Shoulder and Elbow Society (ASES) and Simple Shoulder Test (SST) scores were compared with regard to age, sex, height, weight, smoking status, WC status, and rotator cuff tear size.

RESULTS

Fifty-four patients were enrolled in this study. At a level of significance of P < .05, BMI showed no correlation with preoperative SST or ASES scores. WC status was negatively correlated with ASES scores. Female sex, WC status, and smoking were each negatively correlated with SST scores. The regression model predictive of preoperative SST scores included sex, WC status, and smoking status. WC status was predictive of ASES scores.

DISCUSSION

To our knowledge, this is the first study to examine BMI as a contributing factor in the magnitude of pain and level of function in patients with chronic rotator cuff tears. Our data suggest that there is no impact of BMI on function/pain. The inter-relationships between factors such as BMI, sex, age, and others are complex, and further study is needed to fully establish that there is no effect.

CONCLUSION

Our hypothesis that BMI is negatively related to magnitude of pain/level of function was not supported. Factors found to be related were sex, WC involvement, and smoking.

Sonographic evaluation of the shoulder in asymptomatic elderly subjects with diabetes

Background

The prevalence of rotator cuff tears increases with age and several studies have shown that diabetes is associated with symptomatic shoulder pathologies. Aim of our research was to evaluate the prevalence of shoulder lesions in a population of asymptomatic elderly subjects, normal and with non insulin - dependent diabetes mellitus.

Methods

The study was performed on 48 subjects with diabetes and 32 controls (mean age: 71.5 ± 4.8 and 70.7 ± 4.5, respectively), who did not complain shoulder pain or dysfunction. An ultrasound examination was performed on both shoulders according to a standard protocol, utilizing multiplanar scans.

Results

Tendons thickness was greater in diabetics than in controls (Supraspinatus Tendon: 6.2 ± 0.09 mm vs 5.2 ± 0.7 mm, p < 0.001; Biceps Tendon: 4 ± 0.8 mm vs 3.2 ± 0.4 mm, p < 0.001). Sonographic appearances of degenerative features in the rotator cuff and biceps were more frequently observed in diabetics (Supraspinatus Tendon: 42.7% vs 20.3%, p < 0.003; Biceps Tendon: 27% vs 7.8%, p < 0.002).

Subjects with diabetes exhibited more tears in the Supraspinatus Tendon (Minor tears: 15 (15.8%) vs 2 (3.1%), p < 0.03; Major tears: 15 (15.8%) vs 5 (7.8%), p = ns), but not in the long head of Biceps. More effusions in subacromial bursa were observed in diabetics (23.9% vs 10.9%, p < 0.03) as well as tenosynovitis in biceps tendon (33.3% vs 10.9%, p < 0.001).

In both groups, pathological findings were prevalent on the dominant side, but no difference related to duration of diabetes was found.

Conclusions

Our results suggest that age - related rotator cuff tendon degenerative changes are more common in diabetics.

Ultrasound is an useful tool for discovering in pre - symptomatic stages the subjects that may undergo shoulder symptomatic pathologies.

Unsuspected sonographic findings in patients with posttraumatic shoulder complaints

PURPOSE

To prospectively assess the frequency of abnormal sonographic findings in patients with posttraumatic shoulder pain and/or disability in whom ultrasound (US) was not considered and to assess the effect of sonographic findings on working diagnosis and therapeutic strategy, to analyze the possible role of US in the diagnostic workup of these patients.

METHODS

A survey was performed under general practitioners and orthopedic surgeons. They were requested to refer patients with persistent posttraumatic complaints for an US examination of the shoulder and to fill out a questionnaire concerning working diagnosis and therapy. In 50 patients examinations were performed separately by two radiologists. Findings were confirmed with additional radiographs and/or MRI and/or surgery. Four weeks after the US examination, the survey was repeated to inquire about changes in diagnosis and/or treatment that resulted from US.

RESULTS

US showed relevant pathology in 45 (90%) of 50 patients, a proximal humerus fracture in 25 (50%) patients, and a rotator cuff tear in 43 (86%) patients. Twenty-three (92%) fractures were accompanied by a rotator cuff tear, and 23 (54%) rotator cuff tears were accompanied by a fracture. Ten fractures were initially missed radiographically. US findings changed the working diagnosis and therapeutic strategy in 37 (74%) and 26 (52%) patients, respectively.

CONCLUSION

In patients with posttraumatic shoulder complaints, US showed a high rate (90%) of relevant pathology. This changed the initial working diagnosis in 74% of the patients and the therapeutic strategy in more than half of the patients. Active referral for US examination may identify these abnormalities in an earlier phase and improve clinical outcome.

Effect of proximal humeral fractures on the age-specific prevalence of rotator cuff tears

BACKGROUND

This study examined the effect of proximal humeral fractures on the age- and shoulder-specific prevalence of rotator cuff tears (RCTs) as well as the association with fracture severity, patient age, and clinical outcome.

METHODS

Sixty-three fractures were treated conservatively; in 114 cases, minimally invasive osteosynthesis, and in 125 cases, open reduction and plate fixation were performed without rotator cuff reconstruction. After 4.4 years, all 302 patients were clinically and sonographically examined.

RESULTS

We examined 139 two-part, 95 three-part, and 68 four-part fractures according to Neer and 134 A, 86 B, and 82 C fractures according to the AO classification. There were 52 patients (17%) with a complete rotator tear (RCT) only at the injured shoulder and 11 patients (4%) with a complete RCT only at the contralateral shoulder (p < 0.0001). Independent of the patient's age at follow-up, the prevalence of an RCT in the fractured shoulder was 13% higher than the prevalence in the opposite shoulder. Four-part fractures showed a significant association with a complete RCT (p = 0.047).Of 74 patients with a satisfactory or poor Constant Score, 33 (44.6%) had RCTs. In the remaining 228 patients with a good to excellent result, only 26 (11.4%) had RCTs. We showed that 66% of the RCTs observed at the fractured shoulder were caused by trauma. There was no association between treatment modality and a complete RCT.

CONCLUSION

RCTs may need special attention in initial diagnostics, management, and follow-up especially in severe proximal humeral fractures.

Accuracy of diagnostic ultrasound in patients with suspected subacromial disorders: a systematic review and meta-analysis

OBJECTIVE

To determine the diagnostic accuracy of ultrasound for detecting subacromial disorders in patients presenting in primary and secondary care settings.

DATA SOURCES

Medline and Embase were searched on June 9, 2010. In addition, the reference list of 1 systematic review and all included articles were searched to identify relevant studies.

STUDY SELECTION

Two reviewers independently selected the articles evaluating the accuracy of ultrasound for detecting subacromial disorders from the title and abstracts retrieved by the literature search. Selection criteria were ultrasound frequency greater than or equal to 7.5MHz as index test, surgery, magnetic resonance imaging and/or radiography as reference standards, and subacromial disorders as target conditions.

DATA EXTRACTION

Two reviewers independently extracted the data on study characteristics and results to construct 2 by 2 tables and performed a methodologic quality assessment.

DATA SYNTHESIS

Twenty-three studies were included: 22 reported on full-thickness rotator cuff tears, 15 on partial-thickness tears, 3 on subacromial bursitis, 2 on tendinopathy, and 2 on calcifying tendonitis, respectively. For full-thickness tears, pooled sensitivity of ultrasound was .95 (95% confidence interval, .90-.97), and specificity .96 (.93-.98). For partial-thickness tears, pooled sensitivity was .72 (.58-.83), and specificity .93 (.89-.96). Statistical pooling was not possible for the other disorders. For subacromial bursitis, sensitivity ranged from .79 to .81, and specificity from .94 to .98. For tendinopathy, sensitivity ranged from .67 to .93, specificity from .88 to 1.00. Sensitivity for calcifying tendonitis was 1.00 in both studies, with specificity ranging from .85 to .98.

CONCLUSIONS

We strongly recommend ultrasound in patients for whom conservative treatment fails, to rule in or out full-thickness tears, to rule in partial-thickness tears, and to a lesser extent to diagnose tendinopathy, subacromial bursitis, and calcifying tendonitis. These results can help physicians tailor treatment.

Shoulder injury related to vaccine administration (SIRVA)

Shoulder pain is a common transient side-effect of vaccination. Infrequently, patients can develop prolonged shoulder pain and dysfunction following vaccination. A series of 13 cases are described in which persistent shoulder dysfunction and pain developed following immunization. Common clinical characteristics include absence of a history of prior shoulder dysfunction, previous exposure to vaccine administered, rapid onset of pain, and limited range of motion. The proposed mechanism of injury is the unintentional injection of antigenic material into synovial tissues resulting in an immune-mediated inflammatory reaction. Careful consideration should be given to appropriate injection technique when administering intramuscular vaccinations to reduce the risk of shoulder injury.

Fewer rotator cuff tears fifteen years after arthroscopic subacromial decompression

BACKGROUND

A successful clinical result is reported in 75% to 85% of impingement patients after arthroscopic subacromial decompression. The result is maintained over time, but few studies have investigated the integrity of the rotator cuff in these patients.

MATERIALS AND METHODS

Using ultrasonography, we examined the integrity of the rotator cuff in 70 patients 15 years after arthroscopic subacromial decompression. All patients had an intact rotator cuff at the index procedure.

RESULTS

Tendons were still intact in 57 patients (82%), 10 (14%) had partial-thickness tears, and 3 (4%) had full-thickness tears.

DISCUSSION

The total number of 18% tears (partial and full thickness) in this study, including patients clinically diagnosed with subacromial impingement at a mean age of 60 years, is unexpectedly low compared with 40% degenerative tears reported in asymptomatic adults of the same age.

CONCLUSION

Arthroscopic subacromial decompression seems to reduce the prevalence of rotator cuff tears in impingement patients. This appears attributable to elimination of extrinsic factors such as mechanical wear and bursitis. The potential effect of surgery on intrinsic cuff degeneration is unknown, but intrinsic factors may explain tears still developing despite decompression.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Tendon bone healing can be enhanced by demineralized bone matrix: a functional and histological study

Rotator cuff repair surgery has high failure rates, with tendon reattachment to bone remaining a challenging clinical problem. Increasing the integrity of the healing tendon-bone interface has been attempted by adopting a number of different augmentation strategies. Because of chondrogenic and osteogenic properties we hypothesise that demineralized bone matrix (DBM) augmentation of a healing tendon-bone interface will result in improved function, and a morphology that more closely resembles that of a normal enthesis, compared with nonaugmented controls in an ovine patellar tendon model. The right patellar tendon was detached from its insertion and reattached to an osteotomized bone bed using suture anchors. Two groups were analyzed, the control group (without augmentation) and the DBM group (DBM interposed between the tendon and bone). Animals were sacrificed at 12 weeks. Force plate, mechanical, and histomorphometric analyses were performed. Tendon repairs failed at a rate of 33 and 0% for the control and DBM groups, respectively. DBM augmentation resulted in significantly improved functional weight bearing and increased amounts of fibrocartilage and mineralized fibrocartilage. This study shows that DBM enhances tendon-bone healing and may reduce the high failure rates associated with rotator cuff repair clinically.

Varicose vein surgery performed by a surgical care practitioner

A surgical care practitioner (SCP) completed a structured training programme to perform all aspects of varicose vein surgery including sapheno-femoral disconnection and long saphenous vein stripping. Over a four-year period, she performed 152 groin procedures, closed 191 groin wounds and undertook phlebectomies on 91 legs with excellent results. A SCP can be used to improve theatre utilization and efficiency with no obvious drawbacks.

Prevalence and characteristics of asymptomatic tears of the rotator cuff

We undertook clinical and ultrasonographic examination of the shoulders of 420 asymptomatic volunteers aged between 50 and 79 years. MRI was performed in selected cases. Full-thickness tears of the rotator cuff were detected in 32 subjects (7.6%). The prevalence increased with age as follows: 50 to 59 years, 2.1%; 60 to 69 years, 5.7%; and 70 to 79 years, 15%. The mean size of the tear was less than 3 cm and tear localisation was limited to the supraspinatus tendon in most cases (78%). The strength of flexion was reduced significantly in the group with tears (p = 0.01).

Asymptomatic tears of the rotator cuff should be regarded as part of the normal ageing process in the elderly but may be less common than hitherto believed.

A new arthroscopic classification of articular-sided supraspinatus footprint lesions: a prospective comparison with Snyder's and Ellman's classification

The aim of this study was to find a descriptive rationale to quantify articular-sided supraspinatus tendon tears in the transverse and coronal planes, leading to a 2-dimensional description of the tear pattern. Fifty-six consecutive patients with articular-sided, symptomatic supraspinatus tendon tears diagnosed clinically and by magnetic resonance imaging underwent standardized diagnostic arthroscopy. Intra-articular findings of the rotator cuff were classified according to Ellman and Snyder. In addition, the longitudinal tear was assessed according to the length of the peeled-off bony footprint in the coronal plane. The sagittal tear extension was defined as a tear of the lateral reflection pulley on the medial border of the supraspinatus tendon and/or a tear in the area of the crescent zone. Statistically, we found a high correlation (r = 0.920, P < .0001) between the classifications of Ellman and Snyder, and we found only a slight correlation between the classifications of Snyder and Ellman with this new classification. Neither the classification of Snyder nor that of Ellman reproduced the extension of the partial-thickness rotator cuff tear in the transverse and coronal planes related to its etiologic pathomorphology.

Identifying the cellular basis for reimplantation failure in repair of the rotator cuff

We examined cultured osteoblasts derived from paired samples from the greater tuberosity and acromion from eight patients with large chronic tears of the rotator cuff. We found that osteoblasts from the tuberosity had no apparent response to mechanical stimulation, whereas those derived from the acromion showed an increase in alkaline phosphatase activity and nitric oxide release which is normally a response of bone cells to mechanical strain. By contrast, we found that cells from both regions were able to respond to dexamethasone, a well-established promoter of osteoblastic differentiation, with the expected increase in alkaline phosphatase activity. Our findings indicate that the failure of repair of the rotator cuff may be due, at least in part, to a compromised capacity for mechanoadaptation within the greater tuberosity. It remains to be seen whether this apparent decrease in the sensitivity of bone cells to mechanical stimulation is the specific consequence of the reduced load-bearing history of the greater tuberosity in these patients.

Tissue engineering approaches to rotator cuff tendon deficiency

Tissue engineering is an emerging scientific approach that may offer alternative pathways for managing tissue degeneration. The use of cellular and acellular matrix in combination with cells and/or growth factors is one approach currently being explored in the management of rotator cuff disease. Interestingly, the integration of gene therapy with this technique introduces a new dimension to treatment options. The scope of this article is to present an overview of the current tissue engineering in vivo methods being clinically investigated in rotator cuff disease.

Management of rotator cuff disease: specific treatment for specific disorders

Disease of the rotator cuff is common. It is responsible for a high proportion of patients with shoulder pain presenting to general practice, causing work absenteeism and claims for sickness benefits. Rotator cuff disease (RCD) can often be managed in primary health care services, although some cases may require secondary referral. Both extrinsic and intrinsic factors to the cuff tendon are thought to be involved in the pathogenesis leading on to a spectrum of conditions ranging from sub-acromial bursitis to mechanical failure of the cuff tendon itself. Careful history and examination followed by pertinent investigation are essential to establish the correct diagnosis. The main aim of treatment is to improve symptoms and restore function of the affected shoulder. The majority of patients suffering from RCD can be managed by conservative means, but a shift in attitude has led to a significant number benefiting from invasive procedures ranging from decompression of the sub-acromial space to large, open procedures reconstructing the tendon itself.

Do shoulder vibration signals vary among asymptomatic volunteers?

Numerous studies document vibrations emanating from joints during active or passive motion. It has been proposed these vibrations, termed vibroarthrographic signals, are associated with changes in the shape or quality of tissues in and around the joint. Vibroarthrographic signals in articular joints have been tested to correlate a particular signal with a particular feature of a joint such as a specific lesion. Because of the limited morphologic changes noted in dominant and nondominant articular joints, we hypothesized shoulder vibroarthrographic signals would be similar between subjects. We determined vibroarthrographic signals in young, adult, asymptomatic volunteers evaluated by 21 different active physician-assisted physical examination tests. Comparisons of data from both shoulders with a two-sample statistical test and a neural network demonstrated difficulty distinguishing the dominant and nondominant shoulder. Four percent of the comparisons were different, and the sensitivity of the neural network averaged 50% for most physical examination tests when classifying shoulder signals as dominant or non-dominant. Our findings suggest future studies investigating vibroarthrographic signals from symptomatic shoulders can be compared with asymptomatic shoulders from young patients with little regard to limb dominance for most physical examination tests.