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Research Reports |
A Cacchio, MD, is Assistant of PM&R, Department of Neuroscience, Physical Medicine and Rehabilitation Unit, "San Salvatore" Hospital of LAquila, Coppito-LAquila, Italy, and Assistant of PM&R, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma, Rome, Italy
M Paoloni, MD, is Assistant of PM&R, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma
A Barile, MD, is Researcher of Radiology, Department of Radiology, School of Medicine, University of LAquila
R Don, MD, is Assistant of PM&R, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma
F de Paulis, MD, is Chief of Radiology at CT Unit, Department of Radiology, "San Salvatore" Hospital of LAquila
V Calvisi, MD, is Professor of Orthopaedic Surgery, Department of Surgery, Orthopaedic Surgery, School of Medicine, University of LAquila
A Ranavolo, MEng, is Researcher of Biomechanics, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma
M Frascarelli, MD, is Professor of PM&R, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma
V Santilli, MD, is Professor and Chief of PM&R Unit, Department of Physical Medicine and Rehabilitation, School of Medicine, "La Sapienza" University of Roma
G Spacca, MD, is Chief of PM&R Unit, Department of Neuroscience, Physical Medicine and Rehabilitation Unit, "San Salvatore" Hospital of LAquila
(angelo.cacchio{at}tin.it) Address all correspondence to Dr Cacchio Angelo at Dipartimento di Neuroscienze, Unità Operativa di Medicina Fisica e Riabilitazione, Ospedale "San Salvatore" di LAquila, via L.Natali 1, 67100 Coppito-LAquila, Italy
Submitted April 7, 2005;
Accepted December 7, 2005
| Abstract |
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Subjects. Ninety patients with radiographically verified calcific tendinitis of the shoulder were tested.
Methods. Subjects were randomly assigned to either a treatment group (n=45) or a control group (n=45). Pain and functional level were evaluated before and after treatment and at a 6-month follow-up. Radiographic modifications in calcifications were evaluated before and after treatment.
Results. The treatment group displayed improvement in all of the parameters analyzed after treatment and at the 6-month follow-up. Calcifications disappeared completely in 86.6% of the subjects in the treatment group and partially in 13.4% of subjects; only 8.8% of the subjects in the control group displayed partially reduced calcifications, and none displayed a total disappearance.
Discussion and Conclusion. The results suggest that the use of RSWT for the management of calcific tendinitis of the shoulder is safe and effective, leading to a significant reduction in pain and improvement of shoulder function after 4 weeks, without adverse effects.
Key Words: Calcific tendinitis Lithotripsy Radial shock-wave therapy Rotator cuff Shoulder
| Introduction |
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The disorder leads to pain, particularly nocturnal discomfort, in about 50% of patients1,12 and frequently to a considerable restriction of range of motion. The clinical presentation varies considerably, and symptoms may last for several days and then either disappear or become chronic,1,13 which means that it has not yet been possible to clearly predict the natural history of the disease. For example, Bosworth1 described the disappearance of calcifications in 9.3% of patients within 3 years of the initial diagnosis. According to Wagenhauser,14 calcifications disappeared in 27.1% of patients after 10 years, and Gartner15 reported that calcifications with sharp margins and a homogeneous or heterogeneous structure disappeared spontaneously in 33% of patients over a period of 3 years. The time required for a spontaneous disappearance of the calcifications, however, often is too long and unacceptable for the patients quality of life.
Treatment of patients with calcific tendinitis is typically conservative and includes the use of nonsteroidal anti-inflammatory drugs, subacromial injection with steroids, percutaneous needle aspiration,16 transcutaneous electrical nerve stimulation,17 and therapeutic exercise,18 all of which have a limited effect19; the only intervention that has been shown to result in a clinical improvement is therapeutic ultrasound.20,21 Open or arthroscopic surgical procedures have been proposed to relieve symptoms for patients with chronic pain, with good results.3,22,23
When conservative therapy has not been effective in relieving pain and other symptoms, extracorporeal shock-wave therapy (ESWT) has been used,11,2428 yielding results such as relief of pain2931 and improved function25,29,31,32 that are sometimes as good as those achieved by means of surgical procedures.28 However, recent randomized controlled trials have shown negative results with the use ESWT for the management of calcific tendinitis.33,34
A radial shock wave (RSW) is a low- to medium-energy shock wave that is pneumatically generated through the acceleration of a projectile inside the handpiece of the treatment device and then transmitted radially from the tip of the applicator to the target zone. The pressure and the energy density decrease by the third power of the penetration depth in the tissue. Radial shock waves show a lower peak pressure and a considerably longer rise time than extracorporeal shock waves (ESWs) (Fig. 1). In radial shock-wave therapy (RSWT), the focal point is not centered on the target zone, as occurs in ESWT, but on the tip of the applicator (Fig. 2). The energy at the focal point of the shock wave per impulse is called the "energy flux density" (EFD) and is recorded as joules per area. The effective total energy of a treatment is defined by the number and EFD of the single impulses and by the geometrical measurement of the focal point. Low-energy shock waves (EFD less than 0.1 mJ/mm2) are generally differentiated from high-energy waves (EFD of 0.20.4 mJ/mm).2,25
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Potential benefits could derive from RSWT, compared with ESWT, because it is less painful and thus can be administered without anesthesia, thereby reducing the risks of treatment for patients. Furthermore, due to the radial emission of RSWT, the calcification, once located radiographically, is surely included inside the wave propagation area. Contrarily, when the shock wave is focused, as occurs in the ESWT, refocusing of the applicator is periodically necessary to be certain that the waves hit the calcification.36 Moreover, no ultrasound guide is needed to perform therapeutic applications of RSWT.
Although RSWT has been successfully used since the late 1990s for the management of various orthopedic disorders such as epicondylitis of the elbow and chronic heel pain,37,38 which represent 2 of the 3 musculoskeletal indications for ESWT (plantar fasciitis, lateral epicondylitis, and calcific tendinitis39), no randomized clinical study has yet been performed in the treatment of shoulder calcifications.
The aim of our study was to evaluate the effectiveness of RSWT on pain relief, restoration of shoulder function, and resolution of calcific tendinitis of the shoulder, using a single-blind, randomized, "less active similar therapy"-controlled study. We considered functionality and pain as primary end points, because we initially did not expect a reduction in calcification, and we considered the radiographic disappearance of calcifications as a secondary end point.
| Subjects and Method |
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4 cm at the moment of the evaluation; presence of symptoms for at least 6 months; failure of previous conservative treatments (anti-inflammatory drugs, ultrasound and exercises, laser therapy and exercises, electrical stimulation and exercises, acupuncture, and steroid injection) (Tab. 1). Exclusion criteria were: rotator cuff tear, glenohumeral or acromioclavicular arthritis or acromioclavicular spur to rule out alternative explanations for the pain; pregnancy; implanted pacemaker; blood coagulation disorders or use of anticoagulant drugs; age of <18 years; inflammatory or neoplastic disorders; presence of type III (cloudy and transparent) calcifications according to the Gartner and Simons radiographic classification6; and conservative treatments administered in the last 4 weeks.
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Outcome Measures
The primary end points were a significant increase in the mean score of the University of CaliforniaLos Angeles (UCLA) Shoulder Rating Scale41,42 and a significant decrease in the VAS score from before to after treatment and to the 6-month follow-up period. The UCLA Shoulder Rating Scale is a 35-point shoulder scale that combines scores for pain, function, active range of forward flexion, strength of forward flexion (manual muscle testing), and patient satisfaction. Pain and function are both scored from 1 to 10 points, with 1 being the worst score and 10 being the best score. Active range of forward flexion, strength of forward flexion, and patient satisfaction are scored from 0 to 5 points, with 0 being the worst score and 5 being the best score. The outcome score is defined as follows: 34 to 35 points, excellent; 29 to 33 points, good; 21 to 28 points, mild; and 20 points or less, poor. The single-administration reliability and the validity of UCLA Shoulder Rating Scale scores compared with Shoulder Pain and Disability Index (SPADI) scores have recently been tested.43 The reliability of the UCLA Shoulder Rating Scale scores, estimated using the Cronbach alpha statistic, could not be assessed because of the typology of the pain and function subscales. Regarding the validity of the UCLA Shoulder Rating Scale scores, negative correlations were found between the SPADI disability subscale scores and the UCLA Shoulder Rating Scale function subscale scores (r=.64) and between the SPADI pain subscale scores and the UCLA Shoulder Rating Scale pain subscale scores (r=.63). To our knowledge, no other publications are available regarding responsiveness, error, and reliability for this scale, even though it has been used for patients with different shoulder conditions, including rotator cuff disease41 and calcific tendinitis.44
Self-rated pain intensity at the moment of the evaluation was measured on a 10-cm horizontal VAS with 0 cm labeled "no pain" and 10 cm labeled "worst pain I have ever had." Subjects were asked to answer the question: "Referring to the worst pain you have experienced in your life, what is the relative level of your shoulder pain?"
The secondary end point was the radiographic disappearance of calcifications at the end of treatment. Success was defined as complete disappearance of calcification. An anteroposterior radiograph of the shoulder obtained in 45 degrees of external rotation and 45 degrees of internal rotation was taken for each subject under standardized conditions in terms of distance from radiographic film and exposure setting45 in order to evaluate the presence, type, and size of calcifications, as well as their location within a specific tendon. Type of calcification was evaluated according to the Gartner and Simons classification.6 A caliper that evaluated calcification length (in millimeters) was used for size measurement. The radiographic assessments were obtained before treatment; post-treatment assessment was performed 1 week after the end of treatment so as to be able to correlate the disappearance of the calcification with the therapy performed.
Primary outcome measurements were performed by 2 experienced physicians. The secondary outcome measurements were assessed by an experienced radiologist. The subjects, the outcome assessors, and the radiologist were all blinded to the treatment performed.
Method of Treatment
A Physio Shock Wave Therapy device* consisting of a control unit, a handpiece with 3 different head applicators (8, 10, and 15 mm), and a medical air compressor was used. The compressor generates a pneumatic energy that is used to accelerate a projectile inside the handpiece. When the projectile strikes the applicator, a shock wave is generated and radially spreads from the tip of the applicator to the target zone.
Subjects were seated with the shoulder abducted at 45 degrees, the elbow flexed at 90 degrees, and the forearm resting on a flat surface, and the shock-wave applicator was placed in the direction of the calcifications. No local anesthetics or analgesic drugs were administered before or during the treatment and no therapeutic cointervention was administered in either the treatment group or the control group. Radial shock-wave therapy was administered in both groups by the same experienced physician (in accordance with Italian law, shock-wave therapy must be administered by a physician and not by a physical therapist).
The RSWT was administered using a 15-mm-head applicator. Each subject in the treatment group received 4 sessions at 1-week intervals, with 2,500 impulses per session (500 impulses with a pressure of 1.5 bar and a frequency of 4.5 Hz and 2,000 impulses with a pressure of 2.5 bar and a frequency of 10 Hz), an EFD of 0.10 mJ/mm2, and a fixed impulse time of 2 milliseconds. The treatment area was prepared with a coupling gel (Aquasonic 100
) to minimize the loss of shock-wave energy at the interface between applicator tip and skin.
The same treatment procedure was followed for the subjects in the control group, except that the total number of impulses administered was only 25 (5 impulses with a pressure of 1.5 bar and a frequency of 4.5 Hz and 20 impulses with a pressure of 2.5 bar and a frequency of 10 Hz). Because we were not able to perform a simulated treatment, we had to give some shock-wave impulse to the control group to avoid possible blinding failure. Other researchers46,47 also have used a "less active similar therapy," and the rationale for this technique is that the efficacy of shock-wave therapy seems to be dose-dependent.25
Data Analysis
Statistical analysis was performed using the SSP 2.5 statistical package (Smiths Statistical Package, version 2.75, 2004
). All analyses of the primary and secondary outcomes were performed according to the principle of intention-to-treat. The intention-to-treat analysis was carried out according to a "worst-case scenario" analysis: subjects who did not complete the treatment or had not undergone the post-treatment or final follow-up assessments were assigned a poor outcome, corresponding to the final average change recorded in the per-protocol completer population in the control group.40 A 2-sample t test was applied to compare the differences of the baseline data. A 2-way analysis of variance (ANOVA) with group (treatment versus control) as the between-subjects factor and time as the within-subjects factor was used to assess the presence of significant differences between the treatment and control groups and within each group before and after treatment and at the 6-month follow-up. A Tukey post hoc comparison was used to determine significant differences between mean values when a significant main effect and interaction were found. Two-sample paired and unpaired t tests were applied to compare the differences of average size of calcium deposits on radiographic examination before and after treatment and between the treatment and control groups, respectively. For all analyses, the level of significance was set at P
.05.
To allow a clinical translation of the statistical results, the number needed to treat (NNT)48 was evaluated. The NNT is expressed in terms designed to help decide whether the intervention might be valuable in clinical practice.48 For example, when comparing treatment X and treatment Y, an NNT score of 5 for treatment X indicates that, on average, after treating 5 patients, treatment X will have achieved one more positive outcome than if treatment Y had been used.48 For the primary outcome, the NNT was calculated considering the "excellent" category (3435 points on the UCLA Shoulder Rating Scale) as a positive outcome and the "good," "mild," and "poor" categories (below 34 points on the UCLA Shoulder Rating Scale) as negative outcomes. For the secondary outcome, number of disappearance of calcifications was used to calculate the NNT.
| Results |
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Adverse Effects
After shock-wave treatment, no clinically relevant side effects were seen in either group. Hematomas that lasted 4 to 6 days were observed in only 3 subjects (6.7%) in the treatment group, but the hematomas did not cause discomfort or pain in the subjects, and they received the remaining RSWT applications. No other adverse effects were noted.
| Discussion |
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Clinical and radiographic results of the current study showed that RSWT is effective in reducing pain, improving shoulder function, and removing calcifications. These results were maintained at the 6-month follow-up. Reduction in pain, as evaluated by VAS scores, was comparable to that observed in other studies in which ESWT was used.11,29 Moreover, the functional improvement of the shoulder, as evaluated with the UCLA Shoulder Rating Scale, was comparable to that obtained by other researchers with the use of ESWT.44
Our study showed that RSWT is effective in dissolving calcifications, and this effect was unexpectedly better than the effect achieved with ESWT in a recent study by Rompe et al.44 Rompe et al44 observed a rate of calcification disappearance of 47% and of partial disappearance of 33%; in our study, calcifications completely disappeared in 86.6% of the subjects in the treatment group and partially disappeared in 13.4% of the subjects.
Differences between ESWT and RSWT in the way the shock waves are administered may contribute to these contrasting results. In RSWT, the calcification, once located radiographically, is surely included inside the wave propagation area. Contrarily, when the shock wave is focused, as occurs in ESWT, refocusing of the applicator periodically is necessary. Haake et al36 achieved poor results when they used ESWT nonfluoroscopically focused on the calcified area to dissolve calcifications in the shoulder, suggesting that it is important to keep the focal spot constantly on the calcific deposit during the entire treatment. Our results suggest that when RSWT is administered, an exact focusing of the shock waves is not required to obtain the disappearance of the calcification due to their radial emission. In RSWT, the applicator was positioned on the posterior or anterior region of the shoulder, according to the radiographic calcification location, which could be on the infraspinatus tendon or on the supraspinatus tendon and, therefore, more posterior or more anterior, respectively. The number of impulses administered in RSWT was greater (2,500 impulses per session) in comparison with the standard number of impulses administered (1,000 impulses per session). In this way, a greater amount of EFD could be aimed at the target zone. More research, however, is needed to confirm this hypothesis.
As shown in the study by Rompe et al,44 a complete disappearance of the calcium deposits was found more frequently in patients with type II calcifications according to the Gartner and Simons classification.6 Rompe et al28 investigated how differences in EFD can modify the ability of the shock wave to dissolve calcifications in the shoulder. In 2 groups of subjects treated with the same ESWT protocol, although with different EFDs (0.06 mJ/mm2 versus 0.28 mJ/mm2), the percentage of calcification disappearance was significantly higher in the high-EFD group (64%) than in the low-EFD group (50%) at the 6-month follow-up; Constant and Murley scores showed a greater effect in the high-EFD group than in the low-EFD group (88 points versus 71 points).
The use of Constant and Murley scores (minimum score of 0 and maximum score of 100, with higher scores reflecting increased function) is a standardized, highly reliable, clinical method of assessing shoulder function. The total score is obtained by adding the results of 4 subscales: subjective pain (15 points), function (20 points), objective clinician assessment of range of motion (40 points), and strength (25 points).
Our results suggest that, using RSWT (EFD=0.10 mJ/mm2, comparable to low-EFD ESTW), 2,500 impulses per session for 4 sessions (total of 10,000 impulses) is more effective in comparison with 25 impulses per session for 4 sessions (total of 100 impulses) for the management of calcific tendinitis of the shoulder. A potential limitation of this study is the lack of a true placebo-control group, even though our results showed a significantly higher rate of success in all of the parameters evaluated in the treatment group and no adverse effects. Use of "less active same therapy," however, was needed to avoid a possible blinding failure.
| Conclusion |
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| Footnotes |
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No author or related institution has received any financial benefit from research in this study.
* Elettronica Pagani Srl, Via De Nicola 4/D, 20037 Paderno Dugnano (MI), Italy. ![]()
Parker Laboratories Inc, 286 Eldridge Rd, Fairfield, NJ 07004. ![]()
Gary Smith, Pomona College, Claremont, Calif 91711 (http://www.economics.pomona.edu/StatSite/framepg.html). ![]()
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This article has been cited by other articles:
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J.-D. Albert, J. Meadeb, P. Guggenbuhl, F. Marin, T. Benkalfate, H. Thomazeau, and G. Chales High-energy extracorporeal shock-wave therapy for calcifying tendinitis of the rotator cuff: A RANDOMISED TRIAL J Bone Joint Surg Br, March 1, 2007; 89-B(3): 335 - 341. [Abstract] [Full Text] [PDF] |
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