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Table of Content - Volume 18 Issue 1 - April 2021
The role of ultrasonography in diagnosing rotator cuff tears and confirmation with arthroscopy
Shahid Latheef1, Thouseef A Majeed2*
1Associate Professor, 2Assistant Professor, Department of Orthopaedics, Al Azhar Medical College, Thodupuzha, Kerala, INDIA. Email: thouseef.dr@gmail.com
Abstract Background: In remote and rural parts of India, Magnetic Resonance Imaging (MRI) is not available, whereas ultrasonography is available and is a comparatively economical mode of investigation. This study was conducted to explore the possibilities of ultrasonography in detecting shoulder injuries, especially rotator cuff injury. The aim of this study was to evaluate the role of ultrasonography of 7-12 MHz in evaluating rotator cuff tear and using arthroscopy as the confirmatory test. Methods: A total of 25 patients were evaluated initially with ultrasonography and then later with arthroscopy. Ultrasonography was performed with a standard handheld ultrasound 7-12 MHz machine, using a linear transducer. Arthroscopy was done using a 30-degree angle camera. Results: Ultrasonography gave a Sensitivity of 100%, Specificity of 72.2% for diagnosing partial thickness tear and Sensitivity of 72.2% and Specificity of 100% in diagnosing full thickness rotator cuff tear. Conclusion: In our study ultrasonography was done and the result confirmed with arthroscopy. It was proved to be reasonably sensitive and specific investigative modality. The results suggest it may be used as a primary mode of investigation for diagnosing rotator cuff tear especially in resource limited settings. Keywords: Arthroscopy, Partial tear, Rotator cuff tear, Ultrasonography
INTRODUCTION Shoulder pain is the third most common musculoskeletal symptom encountered in medical practice after back and neck pain. The point prevalence of shoulder pain has been estimated to be 7–25% and the incidence as 10 per 1,000 per year, peaking at 25 per 1,000 per year among individuals with ages 42–46 years1,2. Early diagnosis helps in the planning of proper surgical treatment and thereby prevent functional impairment. Sonographic evaluation of the rotator cuff was initially attempted over two decades ago by radiologists, but not to that extent awarding the attention it deserved. Early reports did not show favourable results of ultrasonography (USG)3. Magnetic resonance imaging (MRI) became rapidly the favoured technique of preoperative shoulder joint evaluation and succeeded in the detection of partial as well as full-thickness rotator cuff tears with high sensitivity and accuracy. Thus, MRI has been considered the imaging modality of choice for evaluating the rotator cuff tears despite its relatively high cost and occasional limited availability4. The technological evolution of high-resolution ultrasound scanners during the last decade allowed substantial improvement in the quality of images and renewed the interest related to USG evaluation of the rotator cuff 4,5.
METHODOLOGY During the study period a total of 25 patients were examined clinically for shoulder injury and were subjected for USG followed by arthroscopy. Informed written consent was obtained from each participant before the conduct of the study. Institutional Ethical Committee approval was also sought prior to the conduct of the study. The clinical examination was conducted by a single examiner to minimise the bias. Real-time ultrasound scanning was performed using a PHILIPS NYZ ultrasound machine with 7 – 10 MHz. Images were obtained by placing transducer both longitudinally and transversely over the shoulder joint with patient seated on a stool. All ultrasonography was performed by the same senior radiologists with an interest in musculoskeletal ultrasound. The radiologist was blinded about the clinical findings of the patient prior to ultrasonography. Images were obtained of the ultrasound and saved for reference. If tears were found, they were classified by the sonologist as full-thickness rotator cuff tear or partial-thickness tear. A thinned cuff or one with a subtle concave contour was considered to be intact in the absence of a focal defect6,7. The extent of the rotator cuff tear was determined with transverse measurements8. Shoulder arthroscopy was performed in all 25 patients who underwent ultrasonography. The lateral decubitus and the beach-chair positions were both used for positioning the patient for arthroscopy. The ultrasound examiner did not participate in surgery of the study patients. The data was collected in Microsoft Excel and analysed using SPSS version 16. All study variables were analysed using descriptive statistical methods like frequencies and percentages for categorical variables and mean with standard deviation for continuous variables. Sensitivity, specificity, and predictive values including both the positive and negative values for the diagnosis of a rotator cuff tear were calculated. For tear size measurement, the coefficient of variation and the 95% limits of agreement for the differences between the results from sonography and surgery are given.
RESULTS All the 25 patients underwent Ultrasonography prior to arthroscopy. All patients were taken strictly through the same study protocol. All patients included in the study, completed the study protocol since there was no follow up required. There were no patients with contraindications for arthroscopy. There were no complications in the study. Study was done on 25 patients who had a mean age of 52.52 years, with the lowest being 36 years and highest being 66 years. In our study 12(48%) were male patients while 13 (52%) were female patients. Dominant side was right in all the patients but affected side was right in 15 patients and left in 10 patients. Mean duration of symptoms was 3.5 months. In our study, ultrasound diagnosed 13 out of 18 cases which had full thickness tears and remaining 5 were reported as partial thickness tears (Table 1). Our results compare favourably with the rates reported in recent previous studies on ultrasonography.
Table 1: Correlation between sonographic and arthroscopy findings in the diagnosis of Partial Thickness tear
PTT – Partial Thickness Tear; ARTH – Arthroscopy; USG – Ultrasonography Ultrasound also picked up all 7 cases which was diagnosed to partial cuff tear in arthroscopy. But it wrongly reported 5 full thickness tears as partial tears, giving a Sensitivity rate of 100 % and Specificity rate of 72%, PPV of 100 % and NPV of 58.3% (Table 2). Table 2: Results of sonographic diagnosis of Partial Thickness Tears
Table 3: Correlation between sonographic and arthroscopy findings in the diagnosis of Full Thickness Tear
FTT – Full Thickness Tear; ARTH – Arthroscopy; USG – Ultrasonography We got sensitivity rate of 72.2%, specificity rate of 100 %, PPV of 58.3% and NPV of 100% for full thickness tear (Table 4). Table 4: Results of sonographic diagnosis of Full Thickness Tears
DISCUSSION The accuracy with which a treating surgeon can determine the integrity of the rotator cuff has important implications for the management of a painful shoulder. Magnetic resonance imaging provides an anatomic picture, demonstrates the quality of the rotator cuff and shows other intra articular and extraarticular pathology. However, the cost of the investigation restricts this modality of investigation in a developing country like India. In the present study the role of ultrasonography was investigated as a primary modality of investigation to assess rotator cuff tear. In contrast to many of the earlier studies, in which the findings on ultrasonography were correlated with those on arthrography, MRI or open surgery, we compared the findings on ultrasonography with those on arthroscopy. Hence the goal of this study was to determine the usefulness of ultrasonography in diagnosing rotator cuff tear and hence to avoid the huge costs involved in investigating this lesion. We found that ultrasound is highly sensitive and specific for detecting cuff tear. It diagnosed 13 out of 18 cases which had full thickness tears and remaining 5 were reported as partial thickness tears. We got sensitivity rate of 72.2% and specificity rate of 100 % for full thickness tear and 100% sensitivity and 72 % specificity for partial thickness tear. Our results compare favourably with the rates reported in other similar studies on ultrasonography. The results of this study were compared with similar study done by Stefan Moosmayer and Hans-Jorgen Smith9. According to their study, in 66 of 79 shoulders, ultrasonographic rotator cuff findings were confirmed at surgery (accuracy 84%). 20 of 26 full-thickness tears were diagnosed correctly; 6 of 7 partial thickness tears were overlooked. Ultrasound was false positive in 1 case. They got a sensitivity of 77%, Specificity of 98%, PPV of 95% and NPV of 90 % for diagnosing rotator cuff tears by ultrasound. Our study was also compared with another study done by Stefan Moosmayer and Stig Heir10. In their study all 24 full thickness tears observed at surgery had been diagnosed correctly via sonography; pre-operative sonography correctly ruled out rotator cuff tear in 19 of 20 cases; 13 of 14 partial thickness tears were not detected via sonography, 1 was misinterpreted as a full thickness tear. They concluded that sonographic examination is effective in the detection of full thickness tears but lacks sensitivity in detecting partial thickness tears. They got a sensitivity of 100 and 66 % for diagnosing full thickness and partial thickness tears respectively and Specificity of 97 and 95 %. Like our study and majority of other similar studies has shown ultrasonography is an excellent investigation modality for detecting rotator cuff lesions especially full thickness tears. Hence Ultrasound can be used as a primary mode of investigation for diagnosing rotator cuff integrity and also as a tool for identifying patients who requires surgical management of rotator cuff injuries.
CONCLUSION According to our study, Ultrasonography has shown excellent sensitivity, specificity, positive predictive value and negative predictive value in diagnosing full thickness tear and a reasonably good choice of investigation for detecting partial thickness rotator cuff tear. Our study has proved that ultrasound is a useful adjuvant tool and provides supportive evidence of rotator cuff lesions and helps in taking appropriate decision regarding management of rotator cuff lesions. Ultrasonography may be considered the primary modality of investigation as it gives a real time dynamic study. However, studies have shown that certain amount of training and experience is required to interpret and report an USG of rotator cuff. Hence it is important to have trained radiologist to report on ultrasound of rotator cuff lesions. In our study all the ultrasound was done by a single experienced radiologist hence having no inter observer variability.
REFERENCES
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