Crescent-shaped rotator cuff tears are relatively

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1 Use of Preoperative Magnetic Resonance Imaging to Predict Rotator Cuff Tear Pattern and Method of Repair J. F. James Davidson, M.D., Stephen S. Burkhart, M.D., David P. Richards, M.D., and Scot E. Campbell, M.D. Purpose: To determine the magnetic resonance imaging (MRI) criteria for predicting rotator cuff tear pattern and method of repair. Type of Study: Retrospective MRI/arthroscopy correlation. Methods: Sixty-six preoperative MRI scans were evaluated. The maximum medial to lateral length (L) of the tear was measured on T2-weighted coronal cuts. The maximum anterior to posterior width (W) was measured on T2-weighted sagittal cuts. The cases were divided into 3 groups: group 1, short-wide tears, L W, L 2 cm; group 2, long-narrow tears, L W, W 2 cm; and group 3, long-wide tears, L 2 cm, W 2 cm. Results: Of the 66 MRI scans, 55 were adequate for standardized measurement. Group 1, 16 cases: 15 were found at arthroscopy to be crescent-shaped tears repaired end-to-bone; 1 was repaired with interval slides. Group 2, 22 cases: all 22 were repaired side-toside/margin convergence. Group 3, 17 cases: 12 required interval slides, 1 partial repair was performed, and 4 were repaired side-to-side/margin convergence. Conclusions: Tear pattern and method of repair can be predicted on high-quality MRI scan. Group 1, L W and L 2 cm, predicts a crescent-shaped tear and end-to-bone repair (positive predictive value, 93.8%). Group 2, L W and W 2 cm, predicts a longitudinal tear and side-to-side/margin convergence repair (positive predictive value 100%). Group 3, L 2 cm and W 2 cm, predicts a massive contracted tear and that primary end-to-bone or side-to-side repairs are usually not possible and that interval slides or partial repair may be necessary (positive predictive value, 76.5%). The overall diagnostic model based on usable MRI scans significantly predicted arthroscopic findings (P.001 for -square test). Level of Evidence: Level III, development of diagnostic criteria with universally applied reference (nonconsecutive patients). Key Words: Rotator cuff tear Arthroscopic repair MRI scan Tear pattern Margin convergence Interval slides. From Canyon Orthopaedic Surgeons (J.F.J.D.) Phoenix, Arizona; the Department of Orthopaedic Surgery, University of Texas Health Science Center at San Antonio, and the San Antonio Orthopaedic Group (S.S.B.), San Antonio, Texas; the Institute for Bone and Joint Disorders (D.P.R.), Phoenix, Arizona; and the Department of Radiology, Lackland Air Force Base (S.E.C.), San Antonio, Texas, U.S.A. Address correspondence and reprint requests to J. F. James Davidson, M.D., 4616 N. 51 Ave, #108, Phoenix, AZ 85031, U.S.A. Shoulders@pol.net 2005 by the Arthroscopy Association of North America /05/ $30.00/0 doi: /j.arthro NOTE: To access the supplementary materials accompanying this report, visit the December 2005 issue of Arthroscopy at Crescent-shaped rotator cuff tears are relatively short and wide. 1-4 The medial to lateral length of these tears is less than the anterior to posterior width (Fig 1A). Crescent-shaped tears are typically mobile from medial to lateral and can usually be repaired by fixing the tendon end directly to the bone bed on the greater humeral tuberosity (Fig 1B). Conversely, longitudinal (U-shaped and L- shaped) tears are relatively long and narrow. 2-4 The medial to lateral length of these tears is greater than the anterior to posterior width. Longitudinal tears are typically mobile in an anterior/posterior direction and can usually be repaired by a side-to-side/ margin convergence technique (Figs 2 and 3). However, if a contracted rotator cuff tear is too large, the tendon end cannot be pulled laterally directly to bone, and the edges cannot be closed directly sideto-side. Other repair techniques such as interval Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 21, No 12 (Dec), 2005: pp 1428.e e e1

2 1428.e2 J.F.J. DAVIDSON ET AL. FIGURE 1. (A) A crescent-shaped tear is short and wide with a medial to lateral length (L) less than anterior to posterior width (W). (B) Crescent tears can usually be repaired with a direct tendon end-to-bone technique. IS, infraspinatus; SS, supraspinatus. slides or partial repairs are necessary for this type of tear (Fig 4) Rotator cuff tears are repaired according to tear pattern. How can preoperative magnetic resonance imaging (MRI) predict the tear pattern and the method of repair? METHODS Sixty-six cases of complete rotator cuff tears repaired by the senior author (S.S.B.) between September 2001 and July 2003 were available for retrospective MRI/arthroscopy correlation. Partial tears, revision repairs, calcific tendonitis, isolated subscapularis tears, and tears associated with humeral fractures were not included in the current study. MRI scans were evaluated to determine if T2- weighted coronal oblique and T2-weighted sagittal oblique images were of adequate quality to make dimension measurements. T2-weighted images were chosen because intact tendons appear dark in contrast to fluid and tears, which appear bright, making this a favored MRI technique to evaluate rotator cuff tears Maximum medial to lateral length (L) was measured on the coronal oblique MRI views, using the scale printed on the scan (Fig 5A). Maximum anterior to posterior width (W) was measured on the sagittal oblique views (Fig 6A). 14 Bright signal with overlying or underlying dark signal suggested areas of partial tear and were not used in the measurement (Figs 5C and 6C). 15,19-21 Complete tears were measured using consistent standards. For simplicity and consistency, all measurements were made along straight lines between edges, and no attempt was made to follow the curvature of the humeral head. On the coronal views, length was measured from the edge of the cuff medially to the stump of the cuff at the insertion site laterally (Fig 5A). If there was no soft-tissue stump laterally, measurement was made to the most superior point of the greater humeral tuberosity (Fig 5B). On the sagittal views, measurements were made from the posterior tendon edge to the anterior tendon or interval tissue edge (Fig 6A). In some cases of massive tears with concomitant subscapularis tears, there was no anterior tissue present to designate the anterior border of the tear. In these cases, the shortest line from the superior coracoid to the humeral head was used to estimate the location of the rotator interval, and measurement was made to this point anteriorly (Fig 6B). There are a variety of tendon edges, and new guidelines were established for this study to measure these consistently. Round and tapered edges were measured at the greatest length. Wispy tissue signal at the tip of a tear was not included in the measurements (Fig 7). FIGURE 2. (A) A U-shaped longitudinal tear is long and narrow. Medial to lateral length (L) is greater than anterior to posterior width (W). (B, C) Longitudinal tears can usually be repaired with a side-to-side/margin convergence technique.

3 ROTATOR CUFF TEAR PATTERN 1428.e3 FIGURE 3. (A) An L-shaped tear is long and narrow. The length (L) is greater than the width (W). (B, C) L-shaped tears can usually be repaired with a side-to-side/margin convergence technique. RI, rotator interval; sub, subscapularis; CHL, coracohumeral ligament. After preliminary analysis of the data, the cases were divided into 3 groups based on preoperative MRI measurements (Tables 1 3, online only available at Group 1, short-wide tears, included all cases with maximum medial to lateral length (L) less than or equal to maximum anterior to posterior width (W) and a maximum length of less than 2 cm as measured on MRI (L W, L 2 cm)(fig 8). Group 2, long-narrow tears, included all cases with length greater than width, and width less than 2 cm (L W, W 2cm)(Fig 9). Group 3, long-wide tears, included all cases with both length and width greater than or equal to 2 cm (L 2 cm, W 2cm)(Fig 10). Arthroscopic examination and repair were performed in the lateral decubitus position. The shape of the tear was best evaluated from the lateral viewing portal. A tendon grasper was used to assess the direction of maximum mobility of the tear to determine if a tendon end-to-bone repair could be achieved or if the tear had mobile anterior and posterior edges that could be apposed by side-to-side repair. 2 Release of the capsule deep to the tendon was not routinely performed. Contracted immobile tears that could not be FIGURE 4. (A) Massive contracted tears are long and wide. Direct end-to-bone, or side-toside repairs are not possible. Interval slides are often required. (B) Anterior and posterior releases are made. (C) After release there is improved tissue mobility. (D) The supraspinatus can then be repaired to the bone bed. (E) The posterior defect is closed with side-to-side sutures.

4 1428.e4 J.F.J. DAVIDSON ET AL. FIGURE 5. (A) The maximum medial to lateral length (L) of tear is measured on T2- weighted coronal oblique MRI views using the scale printed on the MRI. (B) If no lateral stump of cuff is present, measurement is made to the apex of the tuberosity. (C) The partial-thickness portion of a tear is not used in measurements. repaired primarily without significant tension were treated with interval slides or partial repairs. 4,11 RESULTS Of the 66 MRI scans initially reviewed, 55 (83%) were of adequate quality for measurement and were used in the analysis. There were 18 women and 37 men, with an average age of 69 years (range, 37 to 77 years). Group 1, L W and L 2 cm, 16 cases: 15 (93.75%) were crescent shaped tears repaired end-tobone. One (6.25%) was repaired with interval slides (Table 1). Group 2, L W, W 2 cm, 22 cases: all 22 (100%) were repaired side-to-side/margin convergence (Table 2). Group 3, L 2cm,W 2cm,17 cases, 12 (70.6%) required interval slides for reconstruction, 1 (5.9%) was treated with partial repair, and 4 (23.5%) were repaired side- to-side/margin convergence (Table 3). Of the 66 initial MRI scans, 11 (17%) were incomplete or of inadequate quality to allow measurement. Four of these studies did not include the T2-weighted sagittal views used in this investigation. One scan did not have a measurement scale. Seven scans showed significant artifact or were of insufficient image resolution to allow reproducible measurement. DISCUSSION FIGURE 6. (A) The maximum anterior to posterior width (W) of a tear is measured on T2-weighted sagittal oblique MRI views using the scale printed on the MRI. (B) In a massive tear, if no anterior tissue is present, the shortest tangential line from the superior coracoid to the humeral head is used to approximate the location of the rotator interval. Measurement is made to this point. (C) The partial-thickness portion of a tear is not used in measurements. Previous studies have proven the sensitivity and specificity of MRI in detecting the presence or absence of full-thickness rotator cuff tears, ranging from 84% to 100% and 93% to 99%, respectively. 15,18-25 Sugihara et al. 14 used MRI to predict primary reparability of massive tears. The current study uniquely shows that high-quality preoperative MRI can predict rotator cuff tear pattern and method of repair. This is clinically significant because better appreciation of basic tear configuration, crescent-shaped or longitudinal (U-shaped and L-shaped) can lead to more precise restoration of anatomy and biomechanics. 2-4,13 Most crescent-shaped tears can be repaired directly to the bone bed at the greater tuberosity without significant tension. However, attempting to laterally mobilize the medial apex of a longitudinal tear to the lateral bone bed can result in significant tensile stress in the middle of the repaired rotator cuff margin and lead to ultimate failure. Side-to-side closure of longitudinal tears has been shown to reduce the strain of the lateral free margin of the cuff in its converged configuration, by

5 ROTATOR CUFF TEAR PATTERN 1428.e5 FIGURE 7. Tendon edges are characterized on the MRI as (A) blunt, (B) tapered, (C) wispy. Measurements are made as depicted. the biomechanical principle of margin convergence. 2-4 Furthermore, massive contracted tears cannot be repaired directly without significant tension, and require additional releases and more complex techniques of reconstruction Previous studies have shown that smaller tears that are repairable primarily have more favorable outcomes than massive contracted tears that require interval slides or partial repair techniques. 2,4,11 It has been shown that crescent-shaped tears repaired with end-to-bone techniques and longitudinal tears repaired with side-to-side/margin convergence techniques both result in good to excellent mean UCLA scores. 2 Massive contracted tears requiring interval slides result in fair to good mean UCLA scores. 4 Finally, massive tears treated with partial repairs resulted in fair mean UCLA scores. 11 With the use of preoperative MRI scans, the surgeon can predict the rotator cuff tear pattern, plan the likely method of repair, and offer some prognostic information to the patient. An MRI scan showing a tear with a medial to lateral length anterior to posterior width, and length less FIGURE 9. Group 2 (L W, W 2 cm) included all cases in which the maximum length (L) measured on the coronal images was greater than the maximum width (W) measured on the sagittal images; and in which the width was less than 2 cm. than2cm(l W, L 2 cm) predicts a crescentshaped tear and an end-to-bone repair (sensitivity, 100%; specificity, 97.5%; positive predictive value, 93.75%; accuracy, 98.2%). An MRI with length greater than width, and width less than 2 cm (L W, W 2 cm) predicts a longitudinal tear and side-toside/margin convergence repair (sensitivity, 84.6%; specificity, 100%; positive predictive value, 100%; accuracy, 92.7%). An MRI with a maximum length 2 cm and maximum width 2cm(L 2 cm, W 2 cm) predicts that interval slides or partial repair are usually necessary, that direct end-to-bone repair is not possible, and that side-to-side repair is usually not possible (sensitivity, 92.9%; specificity, 90.2%; positive predictive value, 76.5%; accuracy, 90.9%) (Figs 11-13). The overall diagnostic model based on usable MRI scans significantly predicted arthroscopic findings (P.001 for -square test). This is a preliminary study and has some limitations. The predictive criteria established are considered useful guidelines and are not absolute. The scans reviewed in this study were from multiple centers FIGURE 8. Group 1 (L W, L 2 cm) included all cases in which the maximum medial to lateral length (L) measured on the coronal MRI images was the maximum anterior to posterior width (W) measured on the sagittal MRI images; and in which the length was less than 2 cm. FIGURE 10. Group 3 included all cases in which both the maximum length (L) measured on coronal MRI images and the maximum width (W) measured on sagittal MRI images were to 2 cm.

6 1428.e6 J.F.J. DAVIDSON ET AL. FIGURE 11. Clinical example of an MRI with the maximum coronal length less than the maximum sagittal width. This correlates with a crescentshaped tear repaired tendon end-to-bone. using a variety of magnet strengths and imaging techniques. Of the scans initially reviewed, 17% were incomplete or of inadequate quality to make standardized measurements. Furthermore, even the best quality MRI is a static examination, and although the size of a tear can be measured, tissue mobility and quality may not be determined until surgery. No attempt was made in this study to evaluate what influence chronicity of the tear or of fatty infiltration might have either on MRI appearance or method of repair. Factors such as these may have contributed to the lower positive predictive values, specificities, and sensitivities for the cases of larger tears in group 3. Additionally, some tears are difficult to measure precisely (e.g., is a given tear 9 mm 10 mm, or 10 mm 9 mm?). Judgment is necessary in making measurements. Previous studies have found interobserver and intraobserver variability in MRI diagnosis of rotator cuff tears. 19,23,26 Reproducibility and reliability in making the measurements presented in this report will be tested in a future study. Surprisingly, in a previous report, Balich et al. 23 found little difference in MRI interpretation of rotator cuff tears by readers blinded and unblinded to the arthroscopic findings. The current study retrospectively reviews MRI scans read in an open fashion with the authors knowledge of the arthroscopic findings of tear pattern and method of repair. A prospective study in which blinded readers make preoperative MRI measurements and use the criteria established in this report to predict cuff tear pattern and method of repair is currently underway. CONCLUSIONS How to predict cuff tear pattern and method of repair on preoperative MRI: FIGURE 12. Clinical example of an MRI with the maximal coronal length greater than the sagittal width. This correlates with a longitudinal tear repaired side-to-side.

7 ROTATOR CUFF TEAR PATTERN 1428.e7 FIGURE 13. Clinical example of an MRI with the maximum coronal length and maximal sagittal length both greater than 2 cm. This correlates with a massive contracted tear in this series, usually treated with interval slides or partial repairs. 1. Measure maximum tear length (L) on T2-weighted coronal image. 2. Measure maximum tear width (W) on T2-weighted sagittal image. 3. L W and L 2 cm predicts a crescent-shaped tear and end-to-bone repair. 4. L W and W 2 cm predicts a longitudinal tear and side-to-side/margin convergence repair. 5. L 2 cm and W 2 cm predicts that, in over 75% of cases, direct primary repair (end-to-bone or sideto-side) is not possible and that other techniques such as interval slides or partial repair are necessary. Acknowledgment: The authors thank Dr. John Schoolfield for the statistical analysis and Nancy Place for the medical illustrations. REFERENCES 1. Burkhart SS. Current concepts: A stepwise approach to arthroscopic rotator cuff repair based on biomechanical principles. Arthroscopy 2000;16: Burkhart SS, Danaceau SM, Pearce CE Jr. Arthroscopic rotator cuff repair: Analysis of results by tear size and by repair technique-margin convergence versus direct tendon-to-bone repair. Arthroscopy 2001;17: Lo IK, Burkhart SS. Biomechanical principles of arthroscopic repair of the rotator cuff. Oper Tech Orthop 2002;12: Lo IK, Burkhart SS. Arthroscopic repair of massive, contracted, immobile rotator cuff tears using single and double interval slides: Technique and preliminary results. Arthroscopy 2004;20: Tauro JC. Arthroscopic rotator cuff repair: Analysis of technique and results at 2-and 3-year follow-up. Arthroscopy 1998; 14: Tauro JC. Arthroscopic interval slide in the repair of large rotator cuff tears. Arthroscopy 1999;15: Cordasco FA, Bigliani LU. The rotator cuff: Large and massive tears. Techniques of open repair. Orthop Clin North Am 1997;28: Codd TP, Flatow EL. Anterior acromioplasty, tendon mobilization and direct repair of massive rotator cuff tears. In: Burkhead WZ, ed. Rotator cuff disorders. Baltimore: Williams & Wilkins, 1996; Burkhart SS. Arthroscopic debridement and decompression for selected rotator cuff tears: Clinical results, pathomechanics, and patient selection based on biomechanical parameters. Orthop Clin North Am 1993;24: Burkhart SS. Reconciling the paradox of rotator cuff repair versus debridement. A unified biomechanical rationale for the treatment of rotator cuff tears. Arthroscopy 1994;10: Burkhart SS, Nottage WM, Ogilvie-Harris DJ, Kohn HS, Pachelli A. Partial repair of irreparable rotator cuff tears. Arthroscopy 1994;10: Burkhart SS. Partial repair of massive rotator cuff tears: The evolution of a concept. Orthop Clin North Am 1997;28: Burkhart SS, Athanasiou KA, Wirth MA. Margin convergence: A method of reducing strain in massive rotator cuff tears. Arthroscopy 1996;12: Sugihara T, Nakagawa T, Tsuchiya M, Ishizuki M. Prediction of primary reparability of massive tears of the rotator cuff on preoperative magnetic resonance imaging. J Shoulder Elbow Surg 2003;12: Seibold CJ, Mallissee TA, Ericson SJ, Boynton MD, Raascu WG, Timins ME. Rotator cuff: Evaluation with US and MR imaging. Radiographics 1999;19: Miller MD, Osborne JR, Warner JP, Fu FH, eds. MRI-arthroscopy correlative atlas. Philadelphia: WB Saunders, Hardin CW, Gillty JS. The armchair adventurer s guide to magnetic resonance imaging: Theory and clinical applications. Oper Tech Sports Med 1995;3: Rafii M, Firooznia H, Sherman O, et al. Rotator cuff lesions: Signal patterns at MR imaging. Radiology 1990;177: Quinn SF, Sheley RC, Demlow TA, Szumowski J. Rotator cuff tendon tears: Evaluation with fat-suppressed MR imaging

8 1428.e8 J.F.J. DAVIDSON ET AL. with arthroscopic correlation in 100 patients. Radiology 1995;195: Singson RD, Hoang T, Dan S, Friedman M. MR evaluation of rotator cuff pathology using T2-weighted fast spin echo technique with and without fat-suppression. AJR Am J Roentgenol 1996;166: Burk DL, Karasick D, Kurtz AB, et al. Rotator cuff tears: Prospective comparison of the MR imaging with arthrography, sonography, and surgery. AJR Am J Roentgenol 1989;153: Iannotti JP, Zlatkin MB, Esterhai JL, et al. Magnetic resonance imaging of the shoulder: Sensitivity, specificity, and predictive value. J Bone Joint Surg Am 1991;73: Balich SM, Sheley RC, Brown TR, Sauser DD, Quinn SF. MR imaging of the rotator cuff tendon: Interobserver agreement and analysis of interpretive errors. Radiology 1997; 204: Nelson MC, Leather GP, Nirschl RP, Pettrone FA, Freedman MT. Evaluation of the painful shoulder. J Bone Joint Surg Am 1991;73: Zlatkin MB, Iannotti JP, Roberts MC, et al. Rotator cuff tears: Diagnostic performance of MR imaging. Radiology 1989;172: Robertson PL, Schweitzer ME, Mitchell DG, et al. Rotator cuff disorders: Interobserver and intraobserver variation in diagnosis with MR imaging. Radiology 1995:194:

9 ROTATOR CUFF TEAR PATTERN 1428.e9 TABLE 1. Group 1, L W, L 2cm L W Age Sex Side Method F R EB M R EB M R EB F R EB F R EB M R EB M R EB M R EB F R EB M L EB M L EB M R EB M L EB F R EB F R EB M L IS Abbreviations: L, length; W, width; R, right; L (in column under Side heading), left; EB, end-to-bone repair; SS, side-to-side repair; IS, interval slides; P, partial repair. TABLE 2. Group 2, L W, W 2cm L W Age Sex Side Method F R SS M L SS F L SS M L SS M R SS M R SS M R SS M R SS M R SS M R SS F R SS M R SS F L SS M R SS F L SS M L SS M R SS F R SS M L SS M R SS M R SS M R SS Abbreviations: L, length; W, width; R, right; L (in column under Side heading), left; EB, end-to-bone repair; SS, side-to-side repair; IS, interval slides; P, partial repair.

10 1428.e10 J.F.J. DAVIDSON ET AL. TABLE 3. Group 3, L 2 cm, W 2cm L W Age Sex Side Method M R IS M L IS F R IS F R IS F R IS M R IS F R IS M L IS M R IS M R IS M L IS M R IS F R P F R SS M R SS M R SS M R SS Abbreviations: L, length; W, width; R, right; L (in column under Side heading), left; EB, end-to-bone repair; SS, side-to-side repair; IS, interval slides; P, partial repair.