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The Prevalence of Rotator Cuff Tears: Is the Contralateral Shoulder at Risk? Dennis Liem, Vera Elisa Buschmann, Carolin Schmidt, Georg Gosheger, Tim Vogler, Tobias L. Schulte and Maurice Balke Am J Sports Med 2014 42: 826 originally published online February 5, 2014 DOI: 10.1177/0363546513519324 The online version of this article can be found at: http://ajs.sagepub.com/content/42/4/826
Published by: http://www.sagepublications.com
On behalf of: American Orthopaedic Society for Sports Medicine
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The Prevalence of Rotator Cuff Tears Is the Contralateral Shoulder at Risk? Dennis Liem,*y MD, Vera Elisa Buschmann,y Carolin Schmidt,y MD, Georg Gosheger,y MD, Prof., Tim Vogler,y MD, Tobias L. Schulte,y MD, Prof., and Maurice Balke,z MD Investigation performed at the Department of Orthopedics and Tumor Orthopedics, University Hospital, Muenster, Germany Background: Rotator cuff tears are a common cause of pain and disability of the shoulder. Information on the prevalence and identification of potential risk factors could help in early detection of rotator cuff tears and improve treatment outcome. Hypothesis: Patients treated for a symptomatic rotator cuff tear on one side have a higher prevalence of rotator cuff tears and decreased shoulder function on the contralateral side compared with an age- and sex-matched group of healthy individuals. Study Design: Case control study; Level of evidence, 3. Methods: One group consisted of 55 patients who had been arthroscopically treated on one shoulder for rotator cuff tear (tear group). In this group, the nonoperated contralateral shoulder was examined. For comparison, the matching shoulder in a control group consisting of 55 subjectively healthy individuals matched by age (61 year) and sex to the tear group was included. Diagnosis of a rotator cuff tear was made by ultrasound. Outcomes were measured using the Constant score. Results: The prevalence of supraspinatus tears was significantly higher (P \ .0001) in the tear group (67.3%) compared with the control group (11.0%). The Constant score for the activities of daily living subscale, however, was significantly lower (18.4) in the tear group compared with the control group (19.9; P = .012). No other subcategory score nor the overall score showed a significant difference. There was a significantly higher tear prevalence in the tear group of patients aged between 50 and 59 years (P \ .001) and 60 and 69 years (P = .004). No tear was diagnosed in the control group in individuals younger than 60 years. Conclusion: Patients treated for partial and full-thickness rotator cuff tears have a significantly higher risk of having a tear on the contralateral side and have noticeable deficits in their shoulder function regarding activities of daily living even if the tear is otherwise asymptomatic. Keywords: rotator cuff tear; contralateral shoulder; ultrasound; shoulder function; asymptomatic; prevalence
Rotator cuff tears are a common cause for pain and disability of the shoulder, and surgical and nonsurgical treatments have been a main focus in the orthopaedic literature. However, it is well known that the actual prevalence of rotator cuff tears in the general population is even higher as a number of these tears are actually asymptomatic. These asymptomatic tears can become symptomatic over time and lead to pain and decreased shoulder function.7 Especially in comparison with data regarding
the outcome of surgical intervention, there are little data on the prevalence of rotator cuff tears, even though these data could provide important information on the so-called natural history of rotator cuff tears. Earlier data regarding rotator cuff tear prevalence were often based on cadaveric studies. In one cadaver study, Hijioka et al5 found a prevalence of 11% for full-thickness tears and 8% for partial tears in 160 shoulders. Newer studies have relied on radiologic examination of symptomatic and asymptomatic patients and generally found numbers exceeding those of the cadaveric studies. In a recent literature review, Reilly et al11 found an overall prevalence of 38.9% for asymptomatic tears and 41.4% for symptomatic partial and fullthickness tears diagnosed by ultrasound compared with a 23.1% prevalence found in cadaveric studies. One of the main factors associated with the prevalence of rotator cuff tears is the individual’s age, which has been reproduced in several prevalence studies. In a comparison of symptomatic and asymptomatic shoulders in 588 patients, Yamaguchi et al17 found a strong correlation between patient’s age and the presence of a rotator cuff tear. Regarding the involvement of the contralateral side,
*Address correspondence to Dennis Liem, MD, Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, AlbertSchweitzer-Str 33, 48149 Muenster, Germany (e-mail: [email protected]). y Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, Germany. z Department of Trauma and Orthopedic Surgery, University of WittenHerdecke, Cologne-Merheim Medical Center, Cologne, Germany. The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. The American Journal of Sports Medicine, Vol. 42, No. 4 DOI: 10.1177/0363546513519324 Ó 2014 The Author(s)
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their results showed that patients had a high prevalence (35.5%) if the other shoulder showed a symptomatic tear. Patients with a bilateral tear were 10 years older than patients with a unilateral tear and 20 years older than patients without a rotator cuff tear, underlining the importance of patient age.17 A difference in age is therefore always a potential confounding factor when comparing 2 groups of patients or the outcome of different study groups unmatched for age. Ultrasound has been identified as a good screening instrument, as it allows for a simpler, quicker, and more accurate diagnosis of rotator cuff tears in comparison with other imaging modalities, such as magnetic resonance imaging (MRI).4,12,14,15 The purpose of this study was to define whether a symptomatic rotator cuff tear on one shoulder predisposes to a higher risk of a rotator cuff tear in the contralateral shoulder regardless of the patient’s age or sex. Therefore, we compared the prevalence of rotator cuff tears in a group of patients with a symptomatic tear on the contralateral shoulder to an age-matched population with subjectively healthy shoulders. The hypothesis was that patients treated for a symptomatic rotator cuff tear on one side had a higher prevalence of rotator cuff tears and decreased shoulder function on the contralateral side compared with an ageand sex-matched group of healthy individuals.
METHODS This study was approved by the local institutional review board. Overall, 110 individuals were examined by ultrasound on 1 shoulder for the prevalence of rotator cuff tears. The first group (tear group) consisted of 55 consecutive patients treated for a symptomatic rotator cuff tear. All patients in this group were treated operatively, and the diagnosis of a partial or complete rotator cuff tear was confirmed arthroscopically. After a recovery period of at least 12 months, these patients underwent standardized clinical and ultrasound examination as part of a screening examination of the contralateral shoulder, which had not previously been treated. Patients were excluded if the contralateral shoulder had already undergone surgical treatment or if the recovery of the operated shoulder showed signs of complications. The second group (control group) consisted of 55 individuals who were matched by sex and age (61 year) to patients in the tear group. These individuals were either patients not treated for shoulder conditions or individuals accompanying other patients. Inclusion criteria were subjectively healthy shoulders not ever treated operatively or nonoperatively. Clinical and ultrasound examination was performed in the same manner as in the tear group on the shoulder that matched the contralateral side of the matched patient in the operated group. Two experienced examiners evaluated the patients in random order, using the Constant score as a measurement tool. Ultrasound examination was performed in all the patients by the same board-certified orthopaedic surgeon with 10 years of experience in ultrasound. To keep
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examiner bias to a minimum, the examiner was not aware of the results of the matching partner in the other group. A linear array transducer (Siemens Acuson 150x; 8 MHz VF10-5) was used in all cases. Transverse and longitudinal images of the supraspinatus, infraspinatus, and subscapularis were taken to identify full-thickness tears or partial tears according to well-defined criteria.13
Statistical Analysis Patient data were collected and later extracted from our patient database and transferred to PASW 20.0. The data were checked for normative variance with the KolmogorovSmirnov test, and if normative variance was found, the t test was used for analysis. Otherwise, the Mann-Whitney U test and the Wilcoxon test were used for comparison. The level of significance was set at P = .05.
RESULTS Through matching, both groups consisted of 31 (56.4%) men and 24 (43.6%) women. In both groups, the right shoulder was involved in 32 cases (58.2%) and the left shoulder in 23 cases (41.8%). The dominant shoulder was examined in 20 cases (36.4%) in the tear group and in 23 cases (41.8%) in the control group. The average patient age was 62.1 years in the tear group and 61.8 years in the control group. The prevalence of supraspinatus tears was 67.3% in the tear group compared with 11.0% in the control group, which was a significant difference (P \ .0001). Regarding the depth of the diagnosed tears, there were 9 full-thickness tears (16.4%) and 28 partial tears (50.9%) in the tear group and 3 full-thickness tears (5.5%) and 3 partial tears (5.5%) in the control group (Table 1). Of the 28 partial supraspinatus tears in the tear group, 24 were articular-sided and 4 bursal-sided tears. All 3 partial tears in the control group were articular-sided partial tears. Partial tears of .50% thickness were found in the tear group in only 7 cases (Table 2); all remaining tears had \50% thickness. In 10 cases (18.2%) in the tear group, the tear extended to the infraspinatus as a posterosuperior massive tear. This was found in only 1 case in the control group (1.8%). This difference was statistically significant (P = .0004). No isolated tears of the infraspinatus were detected. Tears extending into the subscapularis were found in 2 patients in the tear group (3.6%) and in no case in the control group. Both cases were massive tears with involvement of the supra- and infraspinatus. Overall, the prevalence of a massive tear involving more than 1 tendon in the contralateral shoulder was significantly higher in the tear group (P \ .0001). There was no difference in the overall Constant score between the 2 groups (85.6 vs 88.6). However, there was a significant difference in the activities of daily living subscore, which was significantly lower (18.4) in the tear group compared with the control group (19.9). There were no significant differences in the other subscales (Table 3). Looking specifically at the pain subscale we analyzed patients who were not completely pain free (pain score \15). This was the case for 12 patients (21.8%) in the
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TABLE 1 Prevalence of Supraspinatus Tears Supraspinatus Tear, No. (%)
Tear group (n = 55) Control group (n = 55)
Intact
Full Thickness
Partial Thickness
Overall
18 (32.7) 49 (89.0)
9 (16.4) 3 (5.5)
28 (50.9) 3 (5.5)
37 (67.3) 6 (11.0)
TABLE 2 Extent of Partial Supraspinatus Tears Articular Sided
TABLE 3 Comparison of Clinical Outcomesa Group 1 (n = 55)
Bursal Sided
Group 2 (n = 55)
P Value
\25% 25%-50% .50% \25% 25%-50% .50% Tear group (n = 28) Control group (n = 3)
11
8
5
0
2
2
2
1
0
0
0
0
Constant score Pain ADL Overall ROM Strength
13.2 18.4 85.6 37.4 16.6
6 6 6 6 6
3.9 3.9 16.2 6.0 6.0
14.8 19.9 88.6 37.7 16.3
6 6 6 6 6
0.6 0.6 9.4 3.0 7.4
.109 .012b .719 .169 .814
a
tear group and 7 patients (12.7%) in the control group. The pain intensity was significantly higher in the tear group (6.7) compared with the control group (13.3; P = .001). Patients with pain showed a rotator cuff tear in 58.3% of cases (7/12) in the tear group and in 28.6% of cases (2/7) in the control group. The tear distribution between the different age groups showed that in the control group, there were no tears in patients younger than 60 years, with the highest prevalence in the group of patients aged between 70 and 79 years (3/8; 37.5%). In the tear group, a high number of tears was found in patients aged between 50 and 59 years (16/18; 88.9%) and 60 and 69 years (12/23; 52.2%). In these age groups, the difference with the control group was statistically significant (Table 4).
Values are expressed as mean 6 standard deviation. ADL, activities of daily living; ROM, range of motion. b Statistically significant difference (P \ .05).
TABLE 4 Age Distribution of Diagnosed Rotator Cuff Tears Tears, No. (%) Age Group, y 30-39 40-49 50-59 60-69 70-79 80-89 Overall
Patients per Group, No. 1 4 18 23 8 1 55
Tear Group 1 0 16 12 7 1 37
(100) (0) (88.9) (52.2) (87.5) (100) (67.3)
Control Group 0 0 0 3 3 0 6
(0) (0) (0) (13.0) (37.5) (0) (11.0)
P Value
\.001 .004 .067 \.001
DISCUSSION To our knowledge, this study is the first to focus specifically on the prevalence of rotator cuff tears in patients with a significant rotator cuff tear on the contralateral side. Results of our study show that patients with a surgically treated symptomatic rotator cuff tear show inferior contralateral shoulder function regarding activities of daily living and have a significantly higher prevalence of rotator cuff tears on the contralateral side even when compared with an age- and sex-matched control group. Thus, both hypotheses were confirmed. This suggests that a rotator cuff tear in one shoulder itself is a risk factor for the presence of at least a partial rotator cuff tear on the contralateral shoulder or that the individual is at risk for developing rotator cuff tears in general, with only 1 side being symptomatic. The work of Yamaguchi et al17 showed an age distribution of almost exactly 10 years between patients without tears (48.7 years), with unilateral rotator cuff tears (58.7
years), and with bilateral rotator cuff tears (67.8 years). In our age-matched study group, we identified a large number of younger patients with bilateral tears (88.9% between 50 and 59 years). Although not all of these tears were symptomatic on examination, these patients had a significantly lower score on the activities of daily living subscale of the Constant score. Also, 12 patients (21.8%) already showed significant pain, with a pain score of 6.7 out of a possible 15 points. These findings suggest that bilateral tears might be more common than previously thought. When comparing our results with those of Yamaguchi et al, it should be noted that the tear group in their study consisted of only fullthickness tears while we also included partial tears. In addition, all of our patients were treated arthroscopically. An interesting finding was that it was actually the subcategory activities of daily living rather than pain that showed a statistically significant inferior outcome. A recent
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study by Nakajima et al9 also found that impairment in activities of daily living was indicative of a rotator cuff tear even if it was not considered painful. Yamamoto et al18 performed ultrasound screening for rotator cuff tears in 683 residents of a Japanese mountain village. A full-thickness rotator cuff tear was found in 283 shoulders in 211 individuals between 34 and 87 years. Almost two-thirds of these tears were asymptomatic (65.4%).18 In this study, patients with a bilateral tear were significantly older than patients with a unilateral tear (70.0 years vs 63.2 years). It should be noted that in our group, tear patients were operated on if the tear could have negatively influenced their activities of daily living. However, the examination took place after a sufficient recovery period from surgery to minimize this effect. In addition, the difference, although statistically significant, was in fact only 1.5 points on the Constant score and might not prove to be clinically relevant. While all patients in the control group considered their shoulder subjectively healthy, 7 patients were not completely pain free (13.3 out of a possible 15 on the pain subscale). This could suggest that the control group was not completely homogeneous and that tear prevalence in this group might be higher than expected. Actually, the tear prevalence in the control group was a combined 11.0%, which is low compared with other studies using ultrasound as the imaging modality.3,8,16 Another interesting finding was that patients in the tear group not only had an overall higher prevalence of contralateral rotator cuff tears but also seemed to develop contralateral tears at a significantly younger age compared with healthy individuals. We found evidence of partial or full-thickness tears in our control group of patients younger than 60 years. In the study by Yamaguchi et al,17 the group without tears also had an average age just less than 60 years (58.7 years). Ultrasound was chosen as the imaging modality for this study as it is readily available at our institution and is established as a standard imaging procedure for shoulder patients. Its accuracy in detecting full-thickness rotator cuff tears has been well established and is comparable with that of MRI.10,12,14,15 The detection of partial-thickness tears can be challenging, but this is found to be the case in MRI studies as well.4 The use of arthro-MRI studies, which have a higher diagnostic accuracy for partial tears, is not applicable in a study involving a healthy control group.4 In contrast with other studies on rotator cuff tear prevalence, the design of the study was a matched-pair design for age (61 year) and sex. This was done to remove these factors as confounding factors and ensure the comparability of the 2 groups. One disadvantage with this design is the low number of patients involved, which is one of the limitations of this study. However, we specifically wanted to remove age as a confounding factor as its influence on tear prevalence is well established. The age distribution and average age of our study group is comparable with that of other studies on this subject.6,17 Results of the contralateral shoulder in the control group were not included in the study; however, there was no statistically significant side-to-side difference detected for either clinical results or sonographic tear prevalence.
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As another limitation of this study, individuals were not checked for other medical issues such as diabetes or hypercholesterolemia or for overuse in the form of manual labor or sports, all of which could have an effect on rotator cuff tear prevalence and could have been a bias between the groups one way or the other.1,2 Patients also were not further evaluated with clinical tests other than those examinations necessary for the Constant score. Thus, there can be no conclusion whether specific tests can be predictive of asymptomatic rotator cuff tears.
CONCLUSION Patients treated for partial and full-thickness rotator cuff tears have a significantly higher risk of developing a tear on the contralateral side. We also found noticeable deficits in these patients’ shoulder function in the subcategory of activities of daily living. This suggests that a tear itself is a risk factor regardless of the patient’s age. As a result of this study, we believe that regular screening of the contralateral shoulder has a significant value, especially in the high-risk population of patients already treated on one shoulder. REFERENCES 1. Abate M, Schiavone C, Salini V. Sonographic evaluation of the shoulder in asymptomatic elderly subjects with diabetes. BMC Musculoskelet Disord. 2010;11(1):278. 2. Abboud JA, Kim JS. The effect of hypercholesterolemia on rotator cuff disease. Clin Orthop Relat Res. 2010;468(6):1493-1497. 3. Crass JR, Craig EV, Feinberg SB. Ultrasonography of rotator cuff tears: a review of 500 diagnostic studies. J Clin Ultrasound. 1988;16(5):313-327. 4. de Jesus JO, Parker L, Frangos AJ, Nazarian LN. Accuracy of MRI, MR arthrography, and ultrasound in the diagnosis of rotator cuff tears: a meta-analysis. Am J Roentgenol. 2009;192(6):1701-1707. 5. Hijioka A, Suzuki K, Nakamura T, Hojo T. Degenerative change and rotator cuff tears: an anatomical study in 160 shoulders of 80 cadavers. Arch Orthop Trauma Surg. 1993;112(2):61-64. 6. Keener JD, Steger-May K, Stobbs G, Yamaguchi K. Asymptomatic rotator cuff tears: patient demographics and baseline shoulder function. J Shoulder Elbow Surg. 2010;19(8):1191-1198. 7. Mall NA, Kim HM, Keener JD, et al. Symptomatic progression of asymptomatic rotator cuff tears: a prospective study of clinical and sonographic variables. J Bone Joint Surg Am. 2010;92(16):26232633. 8. Milgrom C, Schaffler M, Gilbert S, van Holsbeeck M. Rotator-cuff changes in asymptomatic adults: the effect of age, hand dominance and gender. J Bone Joint Surg Br. 1995;77(2):296-298. 9. Nakajima D, Yamamoto A, Kobayashi T, et al. The effects of rotator cuff tears, including shoulders without pain, on activities of daily living in the general population. J Orthop Sci. 2012;17(2):136-140. 10. Ottenheijm RP, Jansen MJ, Staal JB, et al. Accuracy of diagnostic ultrasound in patients with suspected subacromial disorders: a systematic review and meta-analysis. Arch Phys Med Rehabil. 2010;91(10):1616-1625. 11. Reilly P, Macleod I, Macfarlane R, Windley J, Emery RJH. Dead men and radiologists don’t lie: a review of cadaveric and radiological studies of rotator cuff tear prevalence. Ann R Coll Surg Engl. 2006;88(2):116-121. 12. Smith TO, Back T, Toms AP, Hing CB. Diagnostic accuracy of ultrasound for rotator cuff tears in adults: a systematic review and metaanalysis. Clin Radiol. 2011;66(11):1036-1048.
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13. Teefey SA, Hasan SA, Middleton WD, Patel M, Wright RW, Yamaguchi K. Ultrasonography of the rotator cuff: a comparison of ultrasonographic and arthroscopic findings in one hundred consecutive cases. J Bone Joint Surg Am. 2000;82(4):498-504. 14. Teefey SA, Middleton WD, Payne WT, Yamaguchi K. Detection and measurement of rotator cuff tears with sonography: analysis of diagnostic errors. AJR Am J Roentgenol. 2005;184(6):1768-1773. 15. Teefey SA, Rubin DA, Middleton WD, Hildebolt CF, Leibold RA, Yamaguchi K. Detection and quantification of rotator cuff tears: comparison of ultrasonographic, magnetic resonance imaging, and arthroscopic findings in seventy-one consecutive cases. J Bone Joint Surg Am. 2004;86(4):708-716.
16. Tempelhof S, Rupp S, Seil R. Age-related prevalence of rotator cuff tears in asymptomatic shoulders. J Shoulder Elbow Surg. 1999;8(4):296-299. 17. Yamaguchi K, Ditsios K, Middleton WD, Hildebolt CF, Galatz LM, Teefey SA. The demographic and morphological features of rotator cuff disease: a comparison of asymptomatic and symptomatic shoulders. J Bone Joint Surg Am. 2006;88(8):1699-1704. 18. Yamamoto A, Takagishi K, Kobayashi T, Shitara H, Osawa T. Factors involved in the presence of symptoms associated with rotator cuff tears: a comparison of asymptomatic and symptomatic rotator cuff tears in the general population. J Shoulder Elbow Surg. 2011;20(7):1133-1137.
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The Prevalence of Rotator Cuff Tears: Is the Contralateral Shoulder at Risk? Dennis Liem, Vera Elisa Buschmann, Carolin Schmidt, Georg Gosheger, Tim Vogler, Tobias L. Schulte and Maurice Balke Am J Sports Med 2014 42: 826 originally published online February 5, 2014 DOI: 10.1177/0363546513519324 The online version of this article can be found at: http://ajs.sagepub.com/content/42/4/826
Published by: http://www.sagepublications.com
On behalf of: American Orthopaedic Society for Sports Medicine
Additional services and information for The American Journal of Sports Medicine can be found at: Email Alerts: http://ajs.sagepub.com/cgi/alerts Subscriptions: http://ajs.sagepub.com/subscriptions Reprints: http://www.sagepub.com/journalsReprints.nav Permissions: http://www.sagepub.com/journalsPermissions.nav
>> Version of Record - Apr 1, 2014 OnlineFirst Version of Record - Feb 5, 2014 What is This?
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The Prevalence of Rotator Cuff Tears Is the Contralateral Shoulder at Risk? Dennis Liem,*y MD, Vera Elisa Buschmann,y Carolin Schmidt,y MD, Georg Gosheger,y MD, Prof., Tim Vogler,y MD, Tobias L. Schulte,y MD, Prof., and Maurice Balke,z MD Investigation performed at the Department of Orthopedics and Tumor Orthopedics, University Hospital, Muenster, Germany Background: Rotator cuff tears are a common cause of pain and disability of the shoulder. Information on the prevalence and identification of potential risk factors could help in early detection of rotator cuff tears and improve treatment outcome. Hypothesis: Patients treated for a symptomatic rotator cuff tear on one side have a higher prevalence of rotator cuff tears and decreased shoulder function on the contralateral side compared with an age- and sex-matched group of healthy individuals. Study Design: Case control study; Level of evidence, 3. Methods: One group consisted of 55 patients who had been arthroscopically treated on one shoulder for rotator cuff tear (tear group). In this group, the nonoperated contralateral shoulder was examined. For comparison, the matching shoulder in a control group consisting of 55 subjectively healthy individuals matched by age (61 year) and sex to the tear group was included. Diagnosis of a rotator cuff tear was made by ultrasound. Outcomes were measured using the Constant score. Results: The prevalence of supraspinatus tears was significantly higher (P \ .0001) in the tear group (67.3%) compared with the control group (11.0%). The Constant score for the activities of daily living subscale, however, was significantly lower (18.4) in the tear group compared with the control group (19.9; P = .012). No other subcategory score nor the overall score showed a significant difference. There was a significantly higher tear prevalence in the tear group of patients aged between 50 and 59 years (P \ .001) and 60 and 69 years (P = .004). No tear was diagnosed in the control group in individuals younger than 60 years. Conclusion: Patients treated for partial and full-thickness rotator cuff tears have a significantly higher risk of having a tear on the contralateral side and have noticeable deficits in their shoulder function regarding activities of daily living even if the tear is otherwise asymptomatic. Keywords: rotator cuff tear; contralateral shoulder; ultrasound; shoulder function; asymptomatic; prevalence
Rotator cuff tears are a common cause for pain and disability of the shoulder, and surgical and nonsurgical treatments have been a main focus in the orthopaedic literature. However, it is well known that the actual prevalence of rotator cuff tears in the general population is even higher as a number of these tears are actually asymptomatic. These asymptomatic tears can become symptomatic over time and lead to pain and decreased shoulder function.7 Especially in comparison with data regarding
the outcome of surgical intervention, there are little data on the prevalence of rotator cuff tears, even though these data could provide important information on the so-called natural history of rotator cuff tears. Earlier data regarding rotator cuff tear prevalence were often based on cadaveric studies. In one cadaver study, Hijioka et al5 found a prevalence of 11% for full-thickness tears and 8% for partial tears in 160 shoulders. Newer studies have relied on radiologic examination of symptomatic and asymptomatic patients and generally found numbers exceeding those of the cadaveric studies. In a recent literature review, Reilly et al11 found an overall prevalence of 38.9% for asymptomatic tears and 41.4% for symptomatic partial and fullthickness tears diagnosed by ultrasound compared with a 23.1% prevalence found in cadaveric studies. One of the main factors associated with the prevalence of rotator cuff tears is the individual’s age, which has been reproduced in several prevalence studies. In a comparison of symptomatic and asymptomatic shoulders in 588 patients, Yamaguchi et al17 found a strong correlation between patient’s age and the presence of a rotator cuff tear. Regarding the involvement of the contralateral side,
*Address correspondence to Dennis Liem, MD, Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, AlbertSchweitzer-Str 33, 48149 Muenster, Germany (e-mail: [email protected]). y Department of Orthopedics and Tumor Orthopedics, University Hospital Muenster, Germany. z Department of Trauma and Orthopedic Surgery, University of WittenHerdecke, Cologne-Merheim Medical Center, Cologne, Germany. The authors declared that they have no conflicts of interest in the authorship and publication of this contribution. The American Journal of Sports Medicine, Vol. 42, No. 4 DOI: 10.1177/0363546513519324 Ó 2014 The Author(s)
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their results showed that patients had a high prevalence (35.5%) if the other shoulder showed a symptomatic tear. Patients with a bilateral tear were 10 years older than patients with a unilateral tear and 20 years older than patients without a rotator cuff tear, underlining the importance of patient age.17 A difference in age is therefore always a potential confounding factor when comparing 2 groups of patients or the outcome of different study groups unmatched for age. Ultrasound has been identified as a good screening instrument, as it allows for a simpler, quicker, and more accurate diagnosis of rotator cuff tears in comparison with other imaging modalities, such as magnetic resonance imaging (MRI).4,12,14,15 The purpose of this study was to define whether a symptomatic rotator cuff tear on one shoulder predisposes to a higher risk of a rotator cuff tear in the contralateral shoulder regardless of the patient’s age or sex. Therefore, we compared the prevalence of rotator cuff tears in a group of patients with a symptomatic tear on the contralateral shoulder to an age-matched population with subjectively healthy shoulders. The hypothesis was that patients treated for a symptomatic rotator cuff tear on one side had a higher prevalence of rotator cuff tears and decreased shoulder function on the contralateral side compared with an ageand sex-matched group of healthy individuals.
METHODS This study was approved by the local institutional review board. Overall, 110 individuals were examined by ultrasound on 1 shoulder for the prevalence of rotator cuff tears. The first group (tear group) consisted of 55 consecutive patients treated for a symptomatic rotator cuff tear. All patients in this group were treated operatively, and the diagnosis of a partial or complete rotator cuff tear was confirmed arthroscopically. After a recovery period of at least 12 months, these patients underwent standardized clinical and ultrasound examination as part of a screening examination of the contralateral shoulder, which had not previously been treated. Patients were excluded if the contralateral shoulder had already undergone surgical treatment or if the recovery of the operated shoulder showed signs of complications. The second group (control group) consisted of 55 individuals who were matched by sex and age (61 year) to patients in the tear group. These individuals were either patients not treated for shoulder conditions or individuals accompanying other patients. Inclusion criteria were subjectively healthy shoulders not ever treated operatively or nonoperatively. Clinical and ultrasound examination was performed in the same manner as in the tear group on the shoulder that matched the contralateral side of the matched patient in the operated group. Two experienced examiners evaluated the patients in random order, using the Constant score as a measurement tool. Ultrasound examination was performed in all the patients by the same board-certified orthopaedic surgeon with 10 years of experience in ultrasound. To keep
827
examiner bias to a minimum, the examiner was not aware of the results of the matching partner in the other group. A linear array transducer (Siemens Acuson 150x; 8 MHz VF10-5) was used in all cases. Transverse and longitudinal images of the supraspinatus, infraspinatus, and subscapularis were taken to identify full-thickness tears or partial tears according to well-defined criteria.13
Statistical Analysis Patient data were collected and later extracted from our patient database and transferred to PASW 20.0. The data were checked for normative variance with the KolmogorovSmirnov test, and if normative variance was found, the t test was used for analysis. Otherwise, the Mann-Whitney U test and the Wilcoxon test were used for comparison. The level of significance was set at P = .05.
RESULTS Through matching, both groups consisted of 31 (56.4%) men and 24 (43.6%) women. In both groups, the right shoulder was involved in 32 cases (58.2%) and the left shoulder in 23 cases (41.8%). The dominant shoulder was examined in 20 cases (36.4%) in the tear group and in 23 cases (41.8%) in the control group. The average patient age was 62.1 years in the tear group and 61.8 years in the control group. The prevalence of supraspinatus tears was 67.3% in the tear group compared with 11.0% in the control group, which was a significant difference (P \ .0001). Regarding the depth of the diagnosed tears, there were 9 full-thickness tears (16.4%) and 28 partial tears (50.9%) in the tear group and 3 full-thickness tears (5.5%) and 3 partial tears (5.5%) in the control group (Table 1). Of the 28 partial supraspinatus tears in the tear group, 24 were articular-sided and 4 bursal-sided tears. All 3 partial tears in the control group were articular-sided partial tears. Partial tears of .50% thickness were found in the tear group in only 7 cases (Table 2); all remaining tears had \50% thickness. In 10 cases (18.2%) in the tear group, the tear extended to the infraspinatus as a posterosuperior massive tear. This was found in only 1 case in the control group (1.8%). This difference was statistically significant (P = .0004). No isolated tears of the infraspinatus were detected. Tears extending into the subscapularis were found in 2 patients in the tear group (3.6%) and in no case in the control group. Both cases were massive tears with involvement of the supra- and infraspinatus. Overall, the prevalence of a massive tear involving more than 1 tendon in the contralateral shoulder was significantly higher in the tear group (P \ .0001). There was no difference in the overall Constant score between the 2 groups (85.6 vs 88.6). However, there was a significant difference in the activities of daily living subscore, which was significantly lower (18.4) in the tear group compared with the control group (19.9). There were no significant differences in the other subscales (Table 3). Looking specifically at the pain subscale we analyzed patients who were not completely pain free (pain score \15). This was the case for 12 patients (21.8%) in the
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TABLE 1 Prevalence of Supraspinatus Tears Supraspinatus Tear, No. (%)
Tear group (n = 55) Control group (n = 55)
Intact
Full Thickness
Partial Thickness
Overall
18 (32.7) 49 (89.0)
9 (16.4) 3 (5.5)
28 (50.9) 3 (5.5)
37 (67.3) 6 (11.0)
TABLE 2 Extent of Partial Supraspinatus Tears Articular Sided
TABLE 3 Comparison of Clinical Outcomesa Group 1 (n = 55)
Bursal Sided
Group 2 (n = 55)
P Value
\25% 25%-50% .50% \25% 25%-50% .50% Tear group (n = 28) Control group (n = 3)
11
8
5
0
2
2
2
1
0
0
0
0
Constant score Pain ADL Overall ROM Strength
13.2 18.4 85.6 37.4 16.6
6 6 6 6 6
3.9 3.9 16.2 6.0 6.0
14.8 19.9 88.6 37.7 16.3
6 6 6 6 6
0.6 0.6 9.4 3.0 7.4
.109 .012b .719 .169 .814
a
tear group and 7 patients (12.7%) in the control group. The pain intensity was significantly higher in the tear group (6.7) compared with the control group (13.3; P = .001). Patients with pain showed a rotator cuff tear in 58.3% of cases (7/12) in the tear group and in 28.6% of cases (2/7) in the control group. The tear distribution between the different age groups showed that in the control group, there were no tears in patients younger than 60 years, with the highest prevalence in the group of patients aged between 70 and 79 years (3/8; 37.5%). In the tear group, a high number of tears was found in patients aged between 50 and 59 years (16/18; 88.9%) and 60 and 69 years (12/23; 52.2%). In these age groups, the difference with the control group was statistically significant (Table 4).
Values are expressed as mean 6 standard deviation. ADL, activities of daily living; ROM, range of motion. b Statistically significant difference (P \ .05).
TABLE 4 Age Distribution of Diagnosed Rotator Cuff Tears Tears, No. (%) Age Group, y 30-39 40-49 50-59 60-69 70-79 80-89 Overall
Patients per Group, No. 1 4 18 23 8 1 55
Tear Group 1 0 16 12 7 1 37
(100) (0) (88.9) (52.2) (87.5) (100) (67.3)
Control Group 0 0 0 3 3 0 6
(0) (0) (0) (13.0) (37.5) (0) (11.0)
P Value
\.001 .004 .067 \.001
DISCUSSION To our knowledge, this study is the first to focus specifically on the prevalence of rotator cuff tears in patients with a significant rotator cuff tear on the contralateral side. Results of our study show that patients with a surgically treated symptomatic rotator cuff tear show inferior contralateral shoulder function regarding activities of daily living and have a significantly higher prevalence of rotator cuff tears on the contralateral side even when compared with an age- and sex-matched control group. Thus, both hypotheses were confirmed. This suggests that a rotator cuff tear in one shoulder itself is a risk factor for the presence of at least a partial rotator cuff tear on the contralateral shoulder or that the individual is at risk for developing rotator cuff tears in general, with only 1 side being symptomatic. The work of Yamaguchi et al17 showed an age distribution of almost exactly 10 years between patients without tears (48.7 years), with unilateral rotator cuff tears (58.7
years), and with bilateral rotator cuff tears (67.8 years). In our age-matched study group, we identified a large number of younger patients with bilateral tears (88.9% between 50 and 59 years). Although not all of these tears were symptomatic on examination, these patients had a significantly lower score on the activities of daily living subscale of the Constant score. Also, 12 patients (21.8%) already showed significant pain, with a pain score of 6.7 out of a possible 15 points. These findings suggest that bilateral tears might be more common than previously thought. When comparing our results with those of Yamaguchi et al, it should be noted that the tear group in their study consisted of only fullthickness tears while we also included partial tears. In addition, all of our patients were treated arthroscopically. An interesting finding was that it was actually the subcategory activities of daily living rather than pain that showed a statistically significant inferior outcome. A recent
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Vol. 42, No. 4, 2014
Rotator Cuff Tear Prevalence
study by Nakajima et al9 also found that impairment in activities of daily living was indicative of a rotator cuff tear even if it was not considered painful. Yamamoto et al18 performed ultrasound screening for rotator cuff tears in 683 residents of a Japanese mountain village. A full-thickness rotator cuff tear was found in 283 shoulders in 211 individuals between 34 and 87 years. Almost two-thirds of these tears were asymptomatic (65.4%).18 In this study, patients with a bilateral tear were significantly older than patients with a unilateral tear (70.0 years vs 63.2 years). It should be noted that in our group, tear patients were operated on if the tear could have negatively influenced their activities of daily living. However, the examination took place after a sufficient recovery period from surgery to minimize this effect. In addition, the difference, although statistically significant, was in fact only 1.5 points on the Constant score and might not prove to be clinically relevant. While all patients in the control group considered their shoulder subjectively healthy, 7 patients were not completely pain free (13.3 out of a possible 15 on the pain subscale). This could suggest that the control group was not completely homogeneous and that tear prevalence in this group might be higher than expected. Actually, the tear prevalence in the control group was a combined 11.0%, which is low compared with other studies using ultrasound as the imaging modality.3,8,16 Another interesting finding was that patients in the tear group not only had an overall higher prevalence of contralateral rotator cuff tears but also seemed to develop contralateral tears at a significantly younger age compared with healthy individuals. We found evidence of partial or full-thickness tears in our control group of patients younger than 60 years. In the study by Yamaguchi et al,17 the group without tears also had an average age just less than 60 years (58.7 years). Ultrasound was chosen as the imaging modality for this study as it is readily available at our institution and is established as a standard imaging procedure for shoulder patients. Its accuracy in detecting full-thickness rotator cuff tears has been well established and is comparable with that of MRI.10,12,14,15 The detection of partial-thickness tears can be challenging, but this is found to be the case in MRI studies as well.4 The use of arthro-MRI studies, which have a higher diagnostic accuracy for partial tears, is not applicable in a study involving a healthy control group.4 In contrast with other studies on rotator cuff tear prevalence, the design of the study was a matched-pair design for age (61 year) and sex. This was done to remove these factors as confounding factors and ensure the comparability of the 2 groups. One disadvantage with this design is the low number of patients involved, which is one of the limitations of this study. However, we specifically wanted to remove age as a confounding factor as its influence on tear prevalence is well established. The age distribution and average age of our study group is comparable with that of other studies on this subject.6,17 Results of the contralateral shoulder in the control group were not included in the study; however, there was no statistically significant side-to-side difference detected for either clinical results or sonographic tear prevalence.
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As another limitation of this study, individuals were not checked for other medical issues such as diabetes or hypercholesterolemia or for overuse in the form of manual labor or sports, all of which could have an effect on rotator cuff tear prevalence and could have been a bias between the groups one way or the other.1,2 Patients also were not further evaluated with clinical tests other than those examinations necessary for the Constant score. Thus, there can be no conclusion whether specific tests can be predictive of asymptomatic rotator cuff tears.
CONCLUSION Patients treated for partial and full-thickness rotator cuff tears have a significantly higher risk of developing a tear on the contralateral side. We also found noticeable deficits in these patients’ shoulder function in the subcategory of activities of daily living. This suggests that a tear itself is a risk factor regardless of the patient’s age. As a result of this study, we believe that regular screening of the contralateral shoulder has a significant value, especially in the high-risk population of patients already treated on one shoulder. REFERENCES 1. Abate M, Schiavone C, Salini V. Sonographic evaluation of the shoulder in asymptomatic elderly subjects with diabetes. BMC Musculoskelet Disord. 2010;11(1):278. 2. Abboud JA, Kim JS. The effect of hypercholesterolemia on rotator cuff disease. Clin Orthop Relat Res. 2010;468(6):1493-1497. 3. Crass JR, Craig EV, Feinberg SB. Ultrasonography of rotator cuff tears: a review of 500 diagnostic studies. J Clin Ultrasound. 1988;16(5):313-327. 4. de Jesus JO, Parker L, Frangos AJ, Nazarian LN. Accuracy of MRI, MR arthrography, and ultrasound in the diagnosis of rotator cuff tears: a meta-analysis. Am J Roentgenol. 2009;192(6):1701-1707. 5. Hijioka A, Suzuki K, Nakamura T, Hojo T. Degenerative change and rotator cuff tears: an anatomical study in 160 shoulders of 80 cadavers. Arch Orthop Trauma Surg. 1993;112(2):61-64. 6. Keener JD, Steger-May K, Stobbs G, Yamaguchi K. Asymptomatic rotator cuff tears: patient demographics and baseline shoulder function. J Shoulder Elbow Surg. 2010;19(8):1191-1198. 7. Mall NA, Kim HM, Keener JD, et al. Symptomatic progression of asymptomatic rotator cuff tears: a prospective study of clinical and sonographic variables. J Bone Joint Surg Am. 2010;92(16):26232633. 8. Milgrom C, Schaffler M, Gilbert S, van Holsbeeck M. Rotator-cuff changes in asymptomatic adults: the effect of age, hand dominance and gender. J Bone Joint Surg Br. 1995;77(2):296-298. 9. Nakajima D, Yamamoto A, Kobayashi T, et al. The effects of rotator cuff tears, including shoulders without pain, on activities of daily living in the general population. J Orthop Sci. 2012;17(2):136-140. 10. Ottenheijm RP, Jansen MJ, Staal JB, et al. Accuracy of diagnostic ultrasound in patients with suspected subacromial disorders: a systematic review and meta-analysis. Arch Phys Med Rehabil. 2010;91(10):1616-1625. 11. Reilly P, Macleod I, Macfarlane R, Windley J, Emery RJH. Dead men and radiologists don’t lie: a review of cadaveric and radiological studies of rotator cuff tear prevalence. Ann R Coll Surg Engl. 2006;88(2):116-121. 12. Smith TO, Back T, Toms AP, Hing CB. Diagnostic accuracy of ultrasound for rotator cuff tears in adults: a systematic review and metaanalysis. Clin Radiol. 2011;66(11):1036-1048.
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13. Teefey SA, Hasan SA, Middleton WD, Patel M, Wright RW, Yamaguchi K. Ultrasonography of the rotator cuff: a comparison of ultrasonographic and arthroscopic findings in one hundred consecutive cases. J Bone Joint Surg Am. 2000;82(4):498-504. 14. Teefey SA, Middleton WD, Payne WT, Yamaguchi K. Detection and measurement of rotator cuff tears with sonography: analysis of diagnostic errors. AJR Am J Roentgenol. 2005;184(6):1768-1773. 15. Teefey SA, Rubin DA, Middleton WD, Hildebolt CF, Leibold RA, Yamaguchi K. Detection and quantification of rotator cuff tears: comparison of ultrasonographic, magnetic resonance imaging, and arthroscopic findings in seventy-one consecutive cases. J Bone Joint Surg Am. 2004;86(4):708-716.
16. Tempelhof S, Rupp S, Seil R. Age-related prevalence of rotator cuff tears in asymptomatic shoulders. J Shoulder Elbow Surg. 1999;8(4):296-299. 17. Yamaguchi K, Ditsios K, Middleton WD, Hildebolt CF, Galatz LM, Teefey SA. The demographic and morphological features of rotator cuff disease: a comparison of asymptomatic and symptomatic shoulders. J Bone Joint Surg Am. 2006;88(8):1699-1704. 18. Yamamoto A, Takagishi K, Kobayashi T, Shitara H, Osawa T. Factors involved in the presence of symptoms associated with rotator cuff tears: a comparison of asymptomatic and symptomatic rotator cuff tears in the general population. J Shoulder Elbow Surg. 2011;20(7):1133-1137.
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