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Magnetic Resonance Imaging Tendon Integrity Assessment After Arthroscopic Partial-Thickness Rotator Cuff Repair
Magnetic Resonance Imaging Tendon Integrity Assessment After Arthroscopic Partial-Thickness Rotator Cuff Repair Jaideep J. Iyengar, M.D., Sharoun Porat, M.D., Keith R. Burnett, M.D., Luis Marrero-Perez, M.D., Victor H. Hernandez, M.D., and Wesley M. Nottage, M.D.
Purpose: Our goal was to assess the integrity of the repaired rotator cuff in patients with partialthickness rotator cuff tears who underwent a technique of tear completion followed by surgical repair, using post-repair magnetic resonance imaging (MRI) at a minimum of 2 years’ follow-up. Methods: An all-arthroscopic surgical technique was used for these marked partial-thickness tears, by use of double-loaded footprint anchors and/or lateral sutures or anchors as appropriate for tissue quality. A total of 22 patients who had completion of the tear followed by repair were reimaged with 2-sequence noncontrast MRI to determine the integrity of the rotator cuff repair at a minimum of 2 years postoperatively. Results: Of the 22 patients, 18 (82%) had no evidence of a full-thickness or near full–thickness defect on follow-up MRI. The presence of a defect on follow-up MRI (18%) did not correlate with clinical results. Younger patients showed a trend toward maintaining better integrity. Conclusions: In 18 of 22 patients (82%) with partial-thickness rotator cuff tears treated with tear completion followed by surgical repair, there was no evidence of a full-thickness or near full– thickness defect on follow-up MRI at a minimum of 2 years. The patient’s age may be an important factor in tendon healing. Level of Evidence: Level IV, therapeutic case series.
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ecent data have shown that the long-term natural history of both articular and bursal-sided marked partial-thickness rotator cuff tears (PTRCTs) is poor without surgical repair.1-3 Yamanaka and Matsumoto4 showed that 80% of articular-sided PTRCTs either enlarged or progressed to a full-thickness tear when they studied a series of 40 cases with repeat magnetic resonance (MR) arthrograms at just over 1 year. Furthermore, debridement of significant PTRCT lesions yields poor results from a clinical standpoint despite
From The Sports Clinic Orthopedic Medical Associates, Inc. (J.J.I., S.P., W.M.N., L.M-P.), Laguna Hills; Laguna Niguel MRI (K.R.B.), Laguna Niguel, California, U.S.A.; and University of Puerto Rico (V.H.H.), San Juan, Puerto Rico. The authors report no conflict of interest. Received August 22, 2009; accepted August 18, 2010. Address correspondence and reprint requests to Wesley M. Nottage, M.D., The Sports Clinic Orthopaedic Medical Associates, 23961 Calle de la Magdalena, Ste 229, Laguna Hills, CA 92653, U.S.A. E-mail: [email protected] © 2011 by the Arthroscopy Association of North America 0749-8063/9501/$36.00 doi:10.1016/j.arthro.2010.08.017
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adequate decompression or acromioplasty.1,2,5,6 Although surgical treatment is now advocated, it remains controversial as to what technique is most effective in addressing significant PTRCT lesions. A number of techniques have been described, and they can be broadly classified as either in situ repair or tear completion followed by repair. Data in the literature regarding the cuff integrity following use of either technique are very limited. We have previously reported favorable clinical outcomes in a cohort of patients who had completion of partial-thickness tears followed by repair.7 Only 1 study showed cuff integrity on ultrasound study after this technique.8 The purpose of this study was to assess the integrity of the repaired rotator cuff at a minimum of 2 years postoperatively in patients with PTRCTs who underwent all-arthroscopic tear completion followed by surgical repair by use of magnetic resonance imaging (MRI) scans. We prefer to take down all unhealthy tissue, which converts significant partial-thickness tears to full-thickness tears, to have the advantages of fresh tendon and raw bone to create
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 27, No 3 (March), 2011: pp 306-313
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR the best environment for healing. We hypothesized that this technique would yield a high rate of cuff integrity, at least equal to that of arthroscopic repair of full-thickness tears. METHODS A retrospective chart review from July 2001 to July 2005 was performed to identify patients who had previously undergone all-arthroscopic takedown and repair as the primary approach for a significant PTRCT lesion. Thirty-four patients were identified; two chose not to participate. Ten initially agreed to participate but did not complete either the assessment or MR scan (or both). The remaining 22 comprise the study group. This group is separate from a prior cohort reported on by Porat et al.7 in 2008. The preoperative diagnosis of partial-thickness tear was accomplished with a complete MRI examination including 5 noncontrast sequences and 4 post-contrast sequences (inclusive of abduction and external rotation [ABER]). All post-contrast sequences were obtained with spectral fat saturation. The diagnosis of partial-thickness tear was established by use of the criteria and classification proposed by Lee and Lee.9 All patients underwent surgical repair after failure of nonsurgical management. The mean time frame of nonsurgical management was 2 months. All patients filled out the University of California, Los Angeles (UCLA) questionnaire preoperatively and at the last follow-up evaluation. Patients (1) with a prior rotator cuff repair, (2) who had not yet reached the minimum 2-year follow-up threshold since surgery, (3) with a less than 50% thickness tear that was treated with only debridement and/or subacromial decompression, and (4) with significant PTRCTs who did not undergo a takedown for conversion to a full-thickness tear before repair and who completed both the clinical assessment and MR scan met the study criteria. Those who did not meet the inclusion criteria were excluded from the study. The criterion of greater than 50% involvement is a well-established threshold in the literature from prior anatomic and clinical work and is the same criterion that was recently chosen in similar studies performed by Kamath et al.,8 Mazzocca et al.,10 and Ide et al.11 Both articular- and bursal-sided tears were included, and no exclusion was made for tear size as long as cuff mobility allowed for repair. Patients contacted for enrollment in the study provided informed consent per our institutional review board–approved protocol (Memorial Health Services IRB No. 626-09) and were referred for standard 2-
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sequence noncontrast MRI (1.5 T) (Siemens Symphony; Siemens AG, Erlangen, Germany). The 2 sequences used for MRI were coronal T2 with fat saturation (field of view, 150 mm; matrix size, 256 ⫻ 256; slice thickness, 3 mm with 0.6-mm interspace; bandwidth, 70; 2 averages) and sagittal T2 fast spin echo (field of view, 150 mm; repetition time, 3,200 milliseconds; echo time, 83 milliseconds; matrix size, 256 ⫻ 256; slice thickness, 3 mm; 1 average). A partial- or full-thickness tear was diagnosed if a high (fluid) signal defect was visualized in the cuff and determined not to be related to artifact. The demographics of the study group are shown in Table 1. Two orthopaedic surgeons and a musculoskeletal radiologist assessed the MR images independently, and failure of healing was defined as a positive finding by at least 2 of the 3 evaluators for the presence of a full-thickness or near full–thickness defect of the rotator cuff. All clinical evaluators (K.R.B., W.M.N., J.J.I.) were in agreement regarding the findings on MRI. Surgical Technique The surgical technique used in all PTRCT repairs was consistent and used an all-arthroscopic approach. Patients were positioned in the lateral decubitus position, and routine glenohumeral assessment was performed at the outset. Marker sutures were inserted in suspicious articular-sided tears before subsequent bursoscopy. Subacromial decompression, acromioplasty, acromioclavicular resection, and other associated procedures were done based on the pathology of the individual patient. TABLE 1.
Study Group Demographics (N ⫽ 22)
Demographics
Data
Age (yr) Female Right shoulder Procedures RCR/SAD RCR/SAD/tenodesis RCR RCR/SAD/SLAP Tear side Articular Bursal MRI findings Intact cuff repair PTRCT Full-thickness rotator cuff defect
57.5 54.5% (12/22) 72.7% (16/22) 81.8% (18/22) 9.1% (2/22) 4.5% (1/22) 4.5% (1/22) 63.6% (14/22) 36.4% (8/22) 59.1% (13/22) 22.7% (5/22) 18.2% (4/22)
Abbreviations: RCR, rotator cuff repair; SAD, subacromial decompression; SLAP, superior labrum anterior and posterior.
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From the bursal view, a 5.5-cm full-radius shaver (Smith & Nephew, Andover, MA) was used for bursal debridement as far as the shaver would pass. Marked PTRCTs would result in takedown of remnants of tendon fibers at the tear site for conversion to a small full-thickness tear. The thickness of the articular PTRCT was measured off the footprint. In general, an assessment of the thickness of the tear was made in all cases by the senior surgeon (W.M.N.), and any tear with involvement of greater than 50% of the tendon thickness was selected for takedown and repair. The senior author’s cutoff criterion for greater than 50% rotator cuff involvement is met when the defect was more than 7 mm off the articular margin.12 Debridement continued by use of the shaver down to a raw and bleeding bone bed at the footprint to stimulate subsequent tendon healing, but leaving cortical bone intact. Anatomic rotator cuff repair was then performed by use of metal suture anchors. All anchors used were TwinFix titanium anchors (Smith & Nephew) double loaded with Arthrex No. 2 FiberWire permanent suture (Arthrex, Naples, FL) to achieve stable footprint fixation. Because all tears were essentially in situ, margin convergence was not needed, rip-stop sutures were not used (because debridement resulted in good-quality tendon), and in all, a singlerow anchor was placed 5 mm lateral to the articular edge for fixation. A single anchor was used in 100% of cases. Postoperative Care In all patients, the extremity was placed in an abduction immobilizer immediately postoperatively. A standardized postoperative rehabilitation regimen was followed: Passive range of motion consisting of pendulum exercises and passive forward flexion was encouraged immediately. Use of the abduction immobilizer was discontinued at 4 weeks, and the patient was then transitioned to an active range-of-motion protocol without resistance for an additional 4 weeks. Internal rotation strengthening was initiated at 8 weeks, and external rotation strengthening commenced at 12 weeks. Release of care typically occurred at about 6 months postoperatively. Statistical Analysis The Student t test and analysis of variance were used to evaluate significant differences between the study groups in terms of function. P ⬍ .05 was considered significant throughout.
RESULTS A total of 22 patients who met the inclusion criteria were reimaged with 2-sequence noncontrast MRI to determine the integrity of their cuff repair at a minimum of 2 years postoperatively. Although 2 patients had undergone prior subacromial decompression, no patient had undergone prior primary rotator cuff repair. A comprehensive list of concurrent surgical procedures performed at the time of primary PTRCT repair is shown in Table 2. Of the 22 patients, 18 (82%) had no evidence of a full-thickness or near full–thickness defect on follow-up MRI. Of the 4 remaining patients, 3 had a near full– thickness defect whereas only 1 had a full-thickness recurrent defect of the rotator cuff. Taken together, the mean age of these 4 patients was 61.5 years, considerably higher than the mean of 57.5 years in the overall study group. Integrity was maintained in 7 of 8 bursal-sided tears (87.5%) and 11 of 14 articular-sided tears (79%). We chose to use the technique of Lee and Lee9 primarily because of our limited imaging (2-sequence coronal T2 and sagittal T2), and we had used the same assessment technique on preoperative MR diagnosis of the partial-thickness tears (Figs 1– 4). Clinical Outcomes Patients in this cohort had a mean preoperative UCLA score (⫾ SD) of 19.14 ⫾ 6.28 and a postoperative outcome of 32.91 ⫾ 2.38 (P ⬍ .001). None of the patients presented with poor outcomes. Patients with no evidence of a rupture on follow-up MRI had the greatest improvement in the UCLA score, with a change of 15 ⫾ 5.4 points versus 10.5 ⫾ 5.6 points in those with a near full–thickness or complete full-
TABLE 2.
Concurrent Surgical Procedures
Concurrent Procedures SAD and acromioplasty* in 21/22 Barbotage of calcification in 1 Subscapularis debridement in 2 Arthroscopic biceps tenodesis in 2 Chronic biceps rupture debridement in 1 Posterior capsulorrhaphy with rotator interval closure and SLAP debridement in 1 Abbreviations: SAD, subacromial decompression; SLAP, superior labrum anterior and posterior. *Of the 2 remaining patients, 1 underwent revision SAD at the time of primary cuff repair and the other was left alone because there was no evidence of recurrent impingement after prior SAD and acromioclavicular resection.
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FIGURE 1. Focal partial-thickness tear (arrow). The artifact next to the high localized tear should be noted.
thickness tear (P ⬍ .001). Correlation between gender, preoperative and postoperative UCLA scores, and rotator cuff status is detailed in Table 3. DISCUSSION In our series 82% of patients had cuff integrity at a minimum of 2 years’ follow-up when assessed with postoperative MRI. In fact, this figure can be considered a conservative estimate, because it includes patients with both full-thickness defects of the cuff (n ⫽ 1) as well as those with near full–thickness defects (n ⫽ 3). If full-thickness defects alone were considered, the integrity rate would increase from 82% to 95%. However, it is our opinion that marked PTRCTs are on a continuum with full-thickness tears in terms of healing potential, and as such, we believe that a
near full–thickness retear behaves structurally and functionally as a low-grade small full-thickness defect. Indeed, that is the central rationale for why we favor a takedown and repair technique for marked PTRCTs in lieu of in situ or transtendon techniques. The presence of incomplete healing defect on followup MRI (n ⫽ 4 [18%]) did not correlate with clinical results. When preoperative and postoperative UCLA scores in the 4 patients with full-thickness and near full–thickness defects were compared, clinical improvement was maintained in this group despite the presence of the defect. This finding is not surprising insofar as it is now well-known and -documented in the literature that clinical outcomes and patient subjective satisfaction remain high despite possible postoperative failure of rotator cuff repairs.13,14 Indeed, we have previously and separately reported on the clinical
FIGURE 2. Partial-thickness lowgrade articular-sided tear (arrow).
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FIGURE 3. Full-thickness tear postoperatively (arrow).
outcomes of a similar cohort of patients who had completion of PTRCTs followed by repair.7 In that study an excellent/good functional outcome was reported in 83% of patients as measured by preoperative and postoperative UCLA scores and physical examination.7 The results were further analyzed as to articularversus bursal-sided origin and patient age to identify whether these variables could serve as surrogate markers of healing potential and, thereby, have some prognostic value. Although significance cannot be reported because of the small sample size, defects of articularand bursal-sided origin seemed to have similar integrity rates, whereas young patients did show a trend toward maintaining better integrity at follow-up. Young age as a positive prognostic factor in healing has been suggested previously, and our data seem to corroborate this finding.8,15 It is also interesting to note that bursal-sided tears seem to respond very favorably because it has been previously observed that
FIGURE 4.
Intact cuff repair postoperatively.
a subgroup of patients with smaller bursal-sided PTRCTs (Ellman grade 2B) had a higher failure rate after acromioplasty alone. This subgroup seems to be particularly well served by primary rotator cuff repair, and the threshold for repair by any technique for these smaller bursal-sided tears should be low.6,16 Strengths of this study include the use of a single surgeon with consistent surgical technique and a standardized postoperative regimen. Because some inherent subjectivity does exist in any study that includes intraoperative decision making, we attempted to minimize this with application of a consistent criterion (⬎50% of tendon thickness involvement), with all cases assessed by the senior shoulder surgeon (W.M.N.). It should be noted that Kamath et al.8 recently reported their clinical and functional outcomes after applying a technique and criteria very similar to ours in high-grade PTRCT supraspinatus lesions, with 37 of 42 shoulders in 41 patients (88%) showing cuff integrity on ultrasound evaluation at a
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR TABLE 3.
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Correlation Between Gender, Preoperative and Postoperative UCLA Scores, and Rotator Cuff Status UCLA Score
Gender
Age
Shoulder Side
Preoperatively
Postoperatively
Tear Site
M M M F F F F F M M M M F F F M M F M F F F
42 56 48 54 67 66 53 62 50 48 53 73 73 72 66 50 57 58 57 54 46 60
L R R R R L R R R R R L L R L R R R R R L R
17 21 33 31 22 15 14 23 29 16 10 14 21 17 11 23 19 12 21 12 18 22
31 33 35 35 35 29 35 30 32 29 27 35 34 32 35 33 35 33 35 35 33 33
Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Bursal Bursal Bursal Bursal Bursal Articular Articular Bursal Bursal Bursal
mean of 11 months postoperatively. Furthermore, they reported an overall patient satisfaction rate of 93%, and patient age was found to be an important predictor of tendon healing (P ⫽ .02).8 These results are strikingly similar to our findings, although the major difference between the 2 studies is our choice of MRI for postoperative imaging as opposed to their use of ultrasound. Prickett et al.17 have validated ultrasound as a postoperative imaging modality at their institution (Washington University, St. Louis, MO); however, ultrasound remains operator dependent and its use is not as ubiquitous in the orthopaedic community as MRI, so we feel that our choice of MRI is a strong point in our study. A review of the literature concerning the efficacy of postoperative imaging after rotator cuff repair shows limitations in the accuracy of both modalities, but MRI seems to yield a slightly higher sensitivity than ultrasound.18 However, it has been noted that although postoperative imaging is less accurate for detecting partial-thickness defects after primary rotator cuff repair, full-thickness tears are readily and reliably diagnosed by MRI.19,20 Therefore, to limit the likelihood of false-negative findings biasing our results, we chose a method that defined recurrent defects as including only full-thickness or near full–thickness
MRI Findings Intact cuff Intact cuff Cuff defect Intact cuff Cuff defect Cuff defect Intact cuff PTRCT PTRCT Intact cuff PTRCT Intact cuff Cuff defect Intact cuff PTRCT Intact cuff Intact cuff Intact cuff Intact cuff Intact cuff PTRCT Intact cuff
(full thickness) (full thickness) (full thickness)
(full thickness)
retears and a positive finding as agreement regarding a recurrent defect by at least 2 of 3 independent evaluators. Additional strengths of the study include the duration of follow-up and the age range of the patient cohort. Although a minimum follow-up time of 2 years was selected as the inclusion criterion, the overall follow-up mean of 50 months and median of 47 months (Table 1) indicate that these results appear to be maintained at midterm follow-up as well. Similarly, the mean overall patient age of 57.1 years and median of 56 years indicate that this analysis was performed in a younger cohort with greater demands on their shoulders than their older counterparts. Weaknesses of the study include the retrospective study design, small sample size of the patient cohort, and lack of a control group. No studies have been reported to date comparing the clinical results of PASTA (partial articular supraspinatus tendon avulsion) or in situ transtendon repairs or other techniques after prospective randomization. A cadaveric study has been reported claiming the superiority of in situ transtendon repair over tear completion and repair, although this study remains limited because it is an in vitro biomechanical analysis with a small sample size of 10 specimens and
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does not seem to be substantiated clinically by our results nor those of Kamath et al.8,21 Furthermore, because concurrent procedures or incidental findings on postoperative MRI in otherwise asymptomatic individuals have the potential to be confounders, we chose to limit the outcome measure to be strictly an MRI-based assessment of recurrent defects in the cuff, irrespective of the clinical status of the patient or any other pathology on postoperative MRI.22,23 Although existing data on the rate of tendon-to-bone healing after rotator cuff repair are limited, Boileau et al.15 reported complete (i.e., watertight) healing in 71% of arthroscopically repaired isolated supraspinatus tears when studied with a combination of computed tomography arthrogram and MRI at a mean of 29 months postoperatively. By conservatively defining failure to include both full-thickness and near full– thickness retears, we believe that the 82% cuff integrity rate at follow-up shows that our preferred primary approach of the takedown and repair technique in PTRCT repairs compares favorably with other published data on various rotator cuff repair techniques. Other weakness include the retrospective design, the lack of control group, the used of just one scoring system and the small patient sample with a low follow-up rate.
CONCLUSIONS We believe that the use of our preferred technique, in which high-grade PTRCT lesions are completed to a full-thickness tear followed by an all-arthroscopic repair, presents a low rate of tendon defects. In 18 of 22 patients (82%) with PTRCTs treated with tear completion followed by surgical repair, there was no evidence of a full-thickness or near full–thickness defect on follow-up MRI at a minimum of 2 years. Our results of an 82% healing rate are comparable to other series of patients treated for PTRCTs and were better than the reported results of debridement and acromioplasty alone. In our opinion, age is an important factor with regard to healing. Our technique represents a reasonable option to treat patients with highgrade PTRCTs.
Acknowledgment: The authors acknowledge Laguna Niguel MRI for donating its time and equipment to perform the study scans.
REFERENCES 1. Kartus J, Kartus C, Rostgard-Christensen L, Sernert N, Read J, Perko M. Long-term clinical and ultrasound evaluation after arthroscopic acromioplasty in patients with partial rotator cuff tears. Arthroscopy 2006;22:44-49. 2. Conway JE. Arthroscopic repair of partial thickness rotator cuff tears and SLAP lesions in professional baseball players. Orthop Clin North Am 2001;32:443-456. 3. Deutsch A. Arthroscopic repair of partial thickness tears of the rotator cuff. J Shoulder Elbow Surg 2007;16:193-201. 4. Yamanaka K, Matsumoto T. The joint side tear of the rotator cuff—A followup study by arthrography. Clin Orthop Relat Res 1994;304:68-73. 5. Weber SC. Arthroscopic debridement and acromioplasty versus mini-open repair in the treatment of significant partialthickness rotator cuff tears. Arthroscopy 1999;15:126-131. 6. Ellman H. Diagnosis and treatment of incomplete rotator cuff tears. Clin Orthop Relat Res 1990;254:64-74. 7. Porat S, Nottage WM, Fouse MN. Repair of partial thickness rotator cuff tears: A retrospective review with minimum twoyear follow-up. J Shoulder Elbow Surg 2008;17:729-731. 8. Kamath G, Galatz LM, Keener JD, Teefey S, Middleton W, Yamaguchi K. Tendon integrity and functional outcome after arthroscopic repair of high-grade partial-thickness supraspinatus tears. J Bone Joint Surg Am 2009;91:1055-1062. 9. Lee SY, Lee JK. Horizontal component of partial-thickness tears of rotator cuff: Imaging characteristics and comparison of ABER view with oblique coronal view at MR arthrography initial results. Radiology 2002;224:470-476. 10. Mazzocca AD, Rincon LM, O’Connor RW, et al. Intra-articular partial thickness rotator cuff tears: Analysis of injured and repaired strain behavior. Am J Sports Med 2008;36:110-116. 11. Ide J, Maeda S, Takagi K. Arthroscopic transtendon repair of partial thickness articular-side tears of the rotator cuff: Anatomical and clinical study. Am J Sports Med 2005;33:16721679. 12. Ruotolo C, Fow JE, Nottage WM. The supraspinatus footprint: An anatomic study of the supraspinatus insertion. Arthroscopy 2004;20:246-249. 13. Galatz LM, Ball CM, Teefey SA, Middleton WD, Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J Bone Joint Surg Am 2004;86:219-224. 14. Jost B, Pfirrmann CW, Gerber C, Switzerland Z. Clinical outcome after structural failure of rotator cuff repairs. J Bone Joint Surg Am 2000;82:304-314. 15. Boileau P, Brassart N, Watkinson DJ, Carles M, Hatzidakis AM, Krishnan SG. Arthroscopic repair of full-thickness tears of the supraspinatus: Does the tendon really heal? J Bone Joint Surg Am 2005;87:1229-1240. 16. Cordasco FA, Backer M, Craig EV, Klein D, Warren RF. The partial thickness rotator cuff tear: Is acromioplasty without repair sufficient? Am J Sports Med 2002;30:257-260. 17. Prickett WD, Teefey SA, Galatz LM, Calfee RP, Middleton WD, Yamaguchi K. Accuracy of ultrasound imaging of the rotator cuff in shoulders that are painful postoperatively. J Bone Joint Surg Am 2003;85:1084-1089. 18. Kraft CN, Fahmy U, Nicolay C, et al. Value of sonography after rotator cuff repair: A comparison with MRI and clinical results. Ultraschall Med 2004;25:40-47 (in German). 19. Knudsen HB, Gelineck J, Sojbjerg JO, Olsen BS, Johannsen HV, Sneppen O. Functional and magnetic resonance imaging evaluation after single-tendon rotator cuff reconstruction. J Shoulder Elbow Surg 1999;8:242-246. 20. Duc SR, Mengiardi B, Pfirrmann CW, Jost B, Hodler J, Zanetti M. Diagnostic performance of MR arthrography after rotator cuff repair. AJR Am J Roentgenol 2006;186:237-241.
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR 21. Gonzalez-Lomas G, Kippe MA, Brown GD, et al. In-situ transtendon repair outperforms tear completion and repair for partial articular-sided supraspinatus tendon tears. J Shoulder Elbow Surg 2008;17:722-728. 22. Zanetti M, Jost B, Hodler J, Gerber C. MR imaging after rotator cuff repair: Full-thickness defects and bursitis-like sub-
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acromial abnormalities in asymptomatic subjects. Skeletal Radiol 2000;29:314-319. 23. Spielmann AL, Forster BB, Kokan P, Hawkins RH, Janzen DL. Shoulder after rotator cuff repair: MR imaging findings in asymptomatic individuals—Initial experience. Radiology 1999;213:705-708.
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Purpose: Our goal was to assess the integrity of the repaired rotator cuff in patients with partialthickness rotator cuff tears who underwent a technique of tear completion followed by surgical repair, using post-repair magnetic resonance imaging (MRI) at a minimum of 2 years’ follow-up. Methods: An all-arthroscopic surgical technique was used for these marked partial-thickness tears, by use of double-loaded footprint anchors and/or lateral sutures or anchors as appropriate for tissue quality. A total of 22 patients who had completion of the tear followed by repair were reimaged with 2-sequence noncontrast MRI to determine the integrity of the rotator cuff repair at a minimum of 2 years postoperatively. Results: Of the 22 patients, 18 (82%) had no evidence of a full-thickness or near full–thickness defect on follow-up MRI. The presence of a defect on follow-up MRI (18%) did not correlate with clinical results. Younger patients showed a trend toward maintaining better integrity. Conclusions: In 18 of 22 patients (82%) with partial-thickness rotator cuff tears treated with tear completion followed by surgical repair, there was no evidence of a full-thickness or near full– thickness defect on follow-up MRI at a minimum of 2 years. The patient’s age may be an important factor in tendon healing. Level of Evidence: Level IV, therapeutic case series.
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ecent data have shown that the long-term natural history of both articular and bursal-sided marked partial-thickness rotator cuff tears (PTRCTs) is poor without surgical repair.1-3 Yamanaka and Matsumoto4 showed that 80% of articular-sided PTRCTs either enlarged or progressed to a full-thickness tear when they studied a series of 40 cases with repeat magnetic resonance (MR) arthrograms at just over 1 year. Furthermore, debridement of significant PTRCT lesions yields poor results from a clinical standpoint despite
From The Sports Clinic Orthopedic Medical Associates, Inc. (J.J.I., S.P., W.M.N., L.M-P.), Laguna Hills; Laguna Niguel MRI (K.R.B.), Laguna Niguel, California, U.S.A.; and University of Puerto Rico (V.H.H.), San Juan, Puerto Rico. The authors report no conflict of interest. Received August 22, 2009; accepted August 18, 2010. Address correspondence and reprint requests to Wesley M. Nottage, M.D., The Sports Clinic Orthopaedic Medical Associates, 23961 Calle de la Magdalena, Ste 229, Laguna Hills, CA 92653, U.S.A. E-mail: [email protected] © 2011 by the Arthroscopy Association of North America 0749-8063/9501/$36.00 doi:10.1016/j.arthro.2010.08.017
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adequate decompression or acromioplasty.1,2,5,6 Although surgical treatment is now advocated, it remains controversial as to what technique is most effective in addressing significant PTRCT lesions. A number of techniques have been described, and they can be broadly classified as either in situ repair or tear completion followed by repair. Data in the literature regarding the cuff integrity following use of either technique are very limited. We have previously reported favorable clinical outcomes in a cohort of patients who had completion of partial-thickness tears followed by repair.7 Only 1 study showed cuff integrity on ultrasound study after this technique.8 The purpose of this study was to assess the integrity of the repaired rotator cuff at a minimum of 2 years postoperatively in patients with PTRCTs who underwent all-arthroscopic tear completion followed by surgical repair by use of magnetic resonance imaging (MRI) scans. We prefer to take down all unhealthy tissue, which converts significant partial-thickness tears to full-thickness tears, to have the advantages of fresh tendon and raw bone to create
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 27, No 3 (March), 2011: pp 306-313
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR the best environment for healing. We hypothesized that this technique would yield a high rate of cuff integrity, at least equal to that of arthroscopic repair of full-thickness tears. METHODS A retrospective chart review from July 2001 to July 2005 was performed to identify patients who had previously undergone all-arthroscopic takedown and repair as the primary approach for a significant PTRCT lesion. Thirty-four patients were identified; two chose not to participate. Ten initially agreed to participate but did not complete either the assessment or MR scan (or both). The remaining 22 comprise the study group. This group is separate from a prior cohort reported on by Porat et al.7 in 2008. The preoperative diagnosis of partial-thickness tear was accomplished with a complete MRI examination including 5 noncontrast sequences and 4 post-contrast sequences (inclusive of abduction and external rotation [ABER]). All post-contrast sequences were obtained with spectral fat saturation. The diagnosis of partial-thickness tear was established by use of the criteria and classification proposed by Lee and Lee.9 All patients underwent surgical repair after failure of nonsurgical management. The mean time frame of nonsurgical management was 2 months. All patients filled out the University of California, Los Angeles (UCLA) questionnaire preoperatively and at the last follow-up evaluation. Patients (1) with a prior rotator cuff repair, (2) who had not yet reached the minimum 2-year follow-up threshold since surgery, (3) with a less than 50% thickness tear that was treated with only debridement and/or subacromial decompression, and (4) with significant PTRCTs who did not undergo a takedown for conversion to a full-thickness tear before repair and who completed both the clinical assessment and MR scan met the study criteria. Those who did not meet the inclusion criteria were excluded from the study. The criterion of greater than 50% involvement is a well-established threshold in the literature from prior anatomic and clinical work and is the same criterion that was recently chosen in similar studies performed by Kamath et al.,8 Mazzocca et al.,10 and Ide et al.11 Both articular- and bursal-sided tears were included, and no exclusion was made for tear size as long as cuff mobility allowed for repair. Patients contacted for enrollment in the study provided informed consent per our institutional review board–approved protocol (Memorial Health Services IRB No. 626-09) and were referred for standard 2-
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sequence noncontrast MRI (1.5 T) (Siemens Symphony; Siemens AG, Erlangen, Germany). The 2 sequences used for MRI were coronal T2 with fat saturation (field of view, 150 mm; matrix size, 256 ⫻ 256; slice thickness, 3 mm with 0.6-mm interspace; bandwidth, 70; 2 averages) and sagittal T2 fast spin echo (field of view, 150 mm; repetition time, 3,200 milliseconds; echo time, 83 milliseconds; matrix size, 256 ⫻ 256; slice thickness, 3 mm; 1 average). A partial- or full-thickness tear was diagnosed if a high (fluid) signal defect was visualized in the cuff and determined not to be related to artifact. The demographics of the study group are shown in Table 1. Two orthopaedic surgeons and a musculoskeletal radiologist assessed the MR images independently, and failure of healing was defined as a positive finding by at least 2 of the 3 evaluators for the presence of a full-thickness or near full–thickness defect of the rotator cuff. All clinical evaluators (K.R.B., W.M.N., J.J.I.) were in agreement regarding the findings on MRI. Surgical Technique The surgical technique used in all PTRCT repairs was consistent and used an all-arthroscopic approach. Patients were positioned in the lateral decubitus position, and routine glenohumeral assessment was performed at the outset. Marker sutures were inserted in suspicious articular-sided tears before subsequent bursoscopy. Subacromial decompression, acromioplasty, acromioclavicular resection, and other associated procedures were done based on the pathology of the individual patient. TABLE 1.
Study Group Demographics (N ⫽ 22)
Demographics
Data
Age (yr) Female Right shoulder Procedures RCR/SAD RCR/SAD/tenodesis RCR RCR/SAD/SLAP Tear side Articular Bursal MRI findings Intact cuff repair PTRCT Full-thickness rotator cuff defect
57.5 54.5% (12/22) 72.7% (16/22) 81.8% (18/22) 9.1% (2/22) 4.5% (1/22) 4.5% (1/22) 63.6% (14/22) 36.4% (8/22) 59.1% (13/22) 22.7% (5/22) 18.2% (4/22)
Abbreviations: RCR, rotator cuff repair; SAD, subacromial decompression; SLAP, superior labrum anterior and posterior.
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From the bursal view, a 5.5-cm full-radius shaver (Smith & Nephew, Andover, MA) was used for bursal debridement as far as the shaver would pass. Marked PTRCTs would result in takedown of remnants of tendon fibers at the tear site for conversion to a small full-thickness tear. The thickness of the articular PTRCT was measured off the footprint. In general, an assessment of the thickness of the tear was made in all cases by the senior surgeon (W.M.N.), and any tear with involvement of greater than 50% of the tendon thickness was selected for takedown and repair. The senior author’s cutoff criterion for greater than 50% rotator cuff involvement is met when the defect was more than 7 mm off the articular margin.12 Debridement continued by use of the shaver down to a raw and bleeding bone bed at the footprint to stimulate subsequent tendon healing, but leaving cortical bone intact. Anatomic rotator cuff repair was then performed by use of metal suture anchors. All anchors used were TwinFix titanium anchors (Smith & Nephew) double loaded with Arthrex No. 2 FiberWire permanent suture (Arthrex, Naples, FL) to achieve stable footprint fixation. Because all tears were essentially in situ, margin convergence was not needed, rip-stop sutures were not used (because debridement resulted in good-quality tendon), and in all, a singlerow anchor was placed 5 mm lateral to the articular edge for fixation. A single anchor was used in 100% of cases. Postoperative Care In all patients, the extremity was placed in an abduction immobilizer immediately postoperatively. A standardized postoperative rehabilitation regimen was followed: Passive range of motion consisting of pendulum exercises and passive forward flexion was encouraged immediately. Use of the abduction immobilizer was discontinued at 4 weeks, and the patient was then transitioned to an active range-of-motion protocol without resistance for an additional 4 weeks. Internal rotation strengthening was initiated at 8 weeks, and external rotation strengthening commenced at 12 weeks. Release of care typically occurred at about 6 months postoperatively. Statistical Analysis The Student t test and analysis of variance were used to evaluate significant differences between the study groups in terms of function. P ⬍ .05 was considered significant throughout.
RESULTS A total of 22 patients who met the inclusion criteria were reimaged with 2-sequence noncontrast MRI to determine the integrity of their cuff repair at a minimum of 2 years postoperatively. Although 2 patients had undergone prior subacromial decompression, no patient had undergone prior primary rotator cuff repair. A comprehensive list of concurrent surgical procedures performed at the time of primary PTRCT repair is shown in Table 2. Of the 22 patients, 18 (82%) had no evidence of a full-thickness or near full–thickness defect on follow-up MRI. Of the 4 remaining patients, 3 had a near full– thickness defect whereas only 1 had a full-thickness recurrent defect of the rotator cuff. Taken together, the mean age of these 4 patients was 61.5 years, considerably higher than the mean of 57.5 years in the overall study group. Integrity was maintained in 7 of 8 bursal-sided tears (87.5%) and 11 of 14 articular-sided tears (79%). We chose to use the technique of Lee and Lee9 primarily because of our limited imaging (2-sequence coronal T2 and sagittal T2), and we had used the same assessment technique on preoperative MR diagnosis of the partial-thickness tears (Figs 1– 4). Clinical Outcomes Patients in this cohort had a mean preoperative UCLA score (⫾ SD) of 19.14 ⫾ 6.28 and a postoperative outcome of 32.91 ⫾ 2.38 (P ⬍ .001). None of the patients presented with poor outcomes. Patients with no evidence of a rupture on follow-up MRI had the greatest improvement in the UCLA score, with a change of 15 ⫾ 5.4 points versus 10.5 ⫾ 5.6 points in those with a near full–thickness or complete full-
TABLE 2.
Concurrent Surgical Procedures
Concurrent Procedures SAD and acromioplasty* in 21/22 Barbotage of calcification in 1 Subscapularis debridement in 2 Arthroscopic biceps tenodesis in 2 Chronic biceps rupture debridement in 1 Posterior capsulorrhaphy with rotator interval closure and SLAP debridement in 1 Abbreviations: SAD, subacromial decompression; SLAP, superior labrum anterior and posterior. *Of the 2 remaining patients, 1 underwent revision SAD at the time of primary cuff repair and the other was left alone because there was no evidence of recurrent impingement after prior SAD and acromioclavicular resection.
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR
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FIGURE 1. Focal partial-thickness tear (arrow). The artifact next to the high localized tear should be noted.
thickness tear (P ⬍ .001). Correlation between gender, preoperative and postoperative UCLA scores, and rotator cuff status is detailed in Table 3. DISCUSSION In our series 82% of patients had cuff integrity at a minimum of 2 years’ follow-up when assessed with postoperative MRI. In fact, this figure can be considered a conservative estimate, because it includes patients with both full-thickness defects of the cuff (n ⫽ 1) as well as those with near full–thickness defects (n ⫽ 3). If full-thickness defects alone were considered, the integrity rate would increase from 82% to 95%. However, it is our opinion that marked PTRCTs are on a continuum with full-thickness tears in terms of healing potential, and as such, we believe that a
near full–thickness retear behaves structurally and functionally as a low-grade small full-thickness defect. Indeed, that is the central rationale for why we favor a takedown and repair technique for marked PTRCTs in lieu of in situ or transtendon techniques. The presence of incomplete healing defect on followup MRI (n ⫽ 4 [18%]) did not correlate with clinical results. When preoperative and postoperative UCLA scores in the 4 patients with full-thickness and near full–thickness defects were compared, clinical improvement was maintained in this group despite the presence of the defect. This finding is not surprising insofar as it is now well-known and -documented in the literature that clinical outcomes and patient subjective satisfaction remain high despite possible postoperative failure of rotator cuff repairs.13,14 Indeed, we have previously and separately reported on the clinical
FIGURE 2. Partial-thickness lowgrade articular-sided tear (arrow).
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FIGURE 3. Full-thickness tear postoperatively (arrow).
outcomes of a similar cohort of patients who had completion of PTRCTs followed by repair.7 In that study an excellent/good functional outcome was reported in 83% of patients as measured by preoperative and postoperative UCLA scores and physical examination.7 The results were further analyzed as to articularversus bursal-sided origin and patient age to identify whether these variables could serve as surrogate markers of healing potential and, thereby, have some prognostic value. Although significance cannot be reported because of the small sample size, defects of articularand bursal-sided origin seemed to have similar integrity rates, whereas young patients did show a trend toward maintaining better integrity at follow-up. Young age as a positive prognostic factor in healing has been suggested previously, and our data seem to corroborate this finding.8,15 It is also interesting to note that bursal-sided tears seem to respond very favorably because it has been previously observed that
FIGURE 4.
Intact cuff repair postoperatively.
a subgroup of patients with smaller bursal-sided PTRCTs (Ellman grade 2B) had a higher failure rate after acromioplasty alone. This subgroup seems to be particularly well served by primary rotator cuff repair, and the threshold for repair by any technique for these smaller bursal-sided tears should be low.6,16 Strengths of this study include the use of a single surgeon with consistent surgical technique and a standardized postoperative regimen. Because some inherent subjectivity does exist in any study that includes intraoperative decision making, we attempted to minimize this with application of a consistent criterion (⬎50% of tendon thickness involvement), with all cases assessed by the senior shoulder surgeon (W.M.N.). It should be noted that Kamath et al.8 recently reported their clinical and functional outcomes after applying a technique and criteria very similar to ours in high-grade PTRCT supraspinatus lesions, with 37 of 42 shoulders in 41 patients (88%) showing cuff integrity on ultrasound evaluation at a
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR TABLE 3.
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Correlation Between Gender, Preoperative and Postoperative UCLA Scores, and Rotator Cuff Status UCLA Score
Gender
Age
Shoulder Side
Preoperatively
Postoperatively
Tear Site
M M M F F F F F M M M M F F F M M F M F F F
42 56 48 54 67 66 53 62 50 48 53 73 73 72 66 50 57 58 57 54 46 60
L R R R R L R R R R R L L R L R R R R R L R
17 21 33 31 22 15 14 23 29 16 10 14 21 17 11 23 19 12 21 12 18 22
31 33 35 35 35 29 35 30 32 29 27 35 34 32 35 33 35 33 35 35 33 33
Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Articular Bursal Bursal Bursal Bursal Bursal Articular Articular Bursal Bursal Bursal
mean of 11 months postoperatively. Furthermore, they reported an overall patient satisfaction rate of 93%, and patient age was found to be an important predictor of tendon healing (P ⫽ .02).8 These results are strikingly similar to our findings, although the major difference between the 2 studies is our choice of MRI for postoperative imaging as opposed to their use of ultrasound. Prickett et al.17 have validated ultrasound as a postoperative imaging modality at their institution (Washington University, St. Louis, MO); however, ultrasound remains operator dependent and its use is not as ubiquitous in the orthopaedic community as MRI, so we feel that our choice of MRI is a strong point in our study. A review of the literature concerning the efficacy of postoperative imaging after rotator cuff repair shows limitations in the accuracy of both modalities, but MRI seems to yield a slightly higher sensitivity than ultrasound.18 However, it has been noted that although postoperative imaging is less accurate for detecting partial-thickness defects after primary rotator cuff repair, full-thickness tears are readily and reliably diagnosed by MRI.19,20 Therefore, to limit the likelihood of false-negative findings biasing our results, we chose a method that defined recurrent defects as including only full-thickness or near full–thickness
MRI Findings Intact cuff Intact cuff Cuff defect Intact cuff Cuff defect Cuff defect Intact cuff PTRCT PTRCT Intact cuff PTRCT Intact cuff Cuff defect Intact cuff PTRCT Intact cuff Intact cuff Intact cuff Intact cuff Intact cuff PTRCT Intact cuff
(full thickness) (full thickness) (full thickness)
(full thickness)
retears and a positive finding as agreement regarding a recurrent defect by at least 2 of 3 independent evaluators. Additional strengths of the study include the duration of follow-up and the age range of the patient cohort. Although a minimum follow-up time of 2 years was selected as the inclusion criterion, the overall follow-up mean of 50 months and median of 47 months (Table 1) indicate that these results appear to be maintained at midterm follow-up as well. Similarly, the mean overall patient age of 57.1 years and median of 56 years indicate that this analysis was performed in a younger cohort with greater demands on their shoulders than their older counterparts. Weaknesses of the study include the retrospective study design, small sample size of the patient cohort, and lack of a control group. No studies have been reported to date comparing the clinical results of PASTA (partial articular supraspinatus tendon avulsion) or in situ transtendon repairs or other techniques after prospective randomization. A cadaveric study has been reported claiming the superiority of in situ transtendon repair over tear completion and repair, although this study remains limited because it is an in vitro biomechanical analysis with a small sample size of 10 specimens and
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does not seem to be substantiated clinically by our results nor those of Kamath et al.8,21 Furthermore, because concurrent procedures or incidental findings on postoperative MRI in otherwise asymptomatic individuals have the potential to be confounders, we chose to limit the outcome measure to be strictly an MRI-based assessment of recurrent defects in the cuff, irrespective of the clinical status of the patient or any other pathology on postoperative MRI.22,23 Although existing data on the rate of tendon-to-bone healing after rotator cuff repair are limited, Boileau et al.15 reported complete (i.e., watertight) healing in 71% of arthroscopically repaired isolated supraspinatus tears when studied with a combination of computed tomography arthrogram and MRI at a mean of 29 months postoperatively. By conservatively defining failure to include both full-thickness and near full– thickness retears, we believe that the 82% cuff integrity rate at follow-up shows that our preferred primary approach of the takedown and repair technique in PTRCT repairs compares favorably with other published data on various rotator cuff repair techniques. Other weakness include the retrospective design, the lack of control group, the used of just one scoring system and the small patient sample with a low follow-up rate.
CONCLUSIONS We believe that the use of our preferred technique, in which high-grade PTRCT lesions are completed to a full-thickness tear followed by an all-arthroscopic repair, presents a low rate of tendon defects. In 18 of 22 patients (82%) with PTRCTs treated with tear completion followed by surgical repair, there was no evidence of a full-thickness or near full–thickness defect on follow-up MRI at a minimum of 2 years. Our results of an 82% healing rate are comparable to other series of patients treated for PTRCTs and were better than the reported results of debridement and acromioplasty alone. In our opinion, age is an important factor with regard to healing. Our technique represents a reasonable option to treat patients with highgrade PTRCTs.
Acknowledgment: The authors acknowledge Laguna Niguel MRI for donating its time and equipment to perform the study scans.
REFERENCES 1. Kartus J, Kartus C, Rostgard-Christensen L, Sernert N, Read J, Perko M. Long-term clinical and ultrasound evaluation after arthroscopic acromioplasty in patients with partial rotator cuff tears. Arthroscopy 2006;22:44-49. 2. Conway JE. Arthroscopic repair of partial thickness rotator cuff tears and SLAP lesions in professional baseball players. Orthop Clin North Am 2001;32:443-456. 3. Deutsch A. Arthroscopic repair of partial thickness tears of the rotator cuff. J Shoulder Elbow Surg 2007;16:193-201. 4. Yamanaka K, Matsumoto T. The joint side tear of the rotator cuff—A followup study by arthrography. Clin Orthop Relat Res 1994;304:68-73. 5. Weber SC. Arthroscopic debridement and acromioplasty versus mini-open repair in the treatment of significant partialthickness rotator cuff tears. Arthroscopy 1999;15:126-131. 6. Ellman H. Diagnosis and treatment of incomplete rotator cuff tears. Clin Orthop Relat Res 1990;254:64-74. 7. Porat S, Nottage WM, Fouse MN. Repair of partial thickness rotator cuff tears: A retrospective review with minimum twoyear follow-up. J Shoulder Elbow Surg 2008;17:729-731. 8. Kamath G, Galatz LM, Keener JD, Teefey S, Middleton W, Yamaguchi K. Tendon integrity and functional outcome after arthroscopic repair of high-grade partial-thickness supraspinatus tears. J Bone Joint Surg Am 2009;91:1055-1062. 9. Lee SY, Lee JK. Horizontal component of partial-thickness tears of rotator cuff: Imaging characteristics and comparison of ABER view with oblique coronal view at MR arthrography initial results. Radiology 2002;224:470-476. 10. Mazzocca AD, Rincon LM, O’Connor RW, et al. Intra-articular partial thickness rotator cuff tears: Analysis of injured and repaired strain behavior. Am J Sports Med 2008;36:110-116. 11. Ide J, Maeda S, Takagi K. Arthroscopic transtendon repair of partial thickness articular-side tears of the rotator cuff: Anatomical and clinical study. Am J Sports Med 2005;33:16721679. 12. Ruotolo C, Fow JE, Nottage WM. The supraspinatus footprint: An anatomic study of the supraspinatus insertion. Arthroscopy 2004;20:246-249. 13. Galatz LM, Ball CM, Teefey SA, Middleton WD, Yamaguchi K. The outcome and repair integrity of completely arthroscopically repaired large and massive rotator cuff tears. J Bone Joint Surg Am 2004;86:219-224. 14. Jost B, Pfirrmann CW, Gerber C, Switzerland Z. Clinical outcome after structural failure of rotator cuff repairs. J Bone Joint Surg Am 2000;82:304-314. 15. Boileau P, Brassart N, Watkinson DJ, Carles M, Hatzidakis AM, Krishnan SG. Arthroscopic repair of full-thickness tears of the supraspinatus: Does the tendon really heal? J Bone Joint Surg Am 2005;87:1229-1240. 16. Cordasco FA, Backer M, Craig EV, Klein D, Warren RF. The partial thickness rotator cuff tear: Is acromioplasty without repair sufficient? Am J Sports Med 2002;30:257-260. 17. Prickett WD, Teefey SA, Galatz LM, Calfee RP, Middleton WD, Yamaguchi K. Accuracy of ultrasound imaging of the rotator cuff in shoulders that are painful postoperatively. J Bone Joint Surg Am 2003;85:1084-1089. 18. Kraft CN, Fahmy U, Nicolay C, et al. Value of sonography after rotator cuff repair: A comparison with MRI and clinical results. Ultraschall Med 2004;25:40-47 (in German). 19. Knudsen HB, Gelineck J, Sojbjerg JO, Olsen BS, Johannsen HV, Sneppen O. Functional and magnetic resonance imaging evaluation after single-tendon rotator cuff reconstruction. J Shoulder Elbow Surg 1999;8:242-246. 20. Duc SR, Mengiardi B, Pfirrmann CW, Jost B, Hodler J, Zanetti M. Diagnostic performance of MR arthrography after rotator cuff repair. AJR Am J Roentgenol 2006;186:237-241.
TENDON INTEGRITY ON MRI AFTER PTRCT REPAIR 21. Gonzalez-Lomas G, Kippe MA, Brown GD, et al. In-situ transtendon repair outperforms tear completion and repair for partial articular-sided supraspinatus tendon tears. J Shoulder Elbow Surg 2008;17:722-728. 22. Zanetti M, Jost B, Hodler J, Gerber C. MR imaging after rotator cuff repair: Full-thickness defects and bursitis-like sub-
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acromial abnormalities in asymptomatic subjects. Skeletal Radiol 2000;29:314-319. 23. Spielmann AL, Forster BB, Kokan P, Hawkins RH, Janzen DL. Shoulder after rotator cuff repair: MR imaging findings in asymptomatic individuals—Initial experience. Radiology 1999;213:705-708.
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