Abstract
Background:
The clinical implications of structural integrity have been a subject of long debate. The oversimplified binary categorization of structural integrity into either healing or retear, along with faulty preoperative baselines for comparison, may contribute to the controversy.
Purpose:
To determine how the quality of structural integrity in a repaired cuff tendon affects both clinical and structural outcomes by dividing the patients into groups based on integrity and using the immediate postoperative baseline (time zero).
Study design:
Cohort study; Level of evidence, 3.
Methods:
A total of 504 patients with a full-thickness rotator cuff tear who underwent arthroscopic rotator cuff repair and were followed up for at least a year with magnetic resonance imaging (MRI) were included. The quality of structural integrity was graded using the Sugaya classification. To evaluate clinical outcomes, pain, range of motion, strength, functional scores, and overall satisfaction and function were used for within- and between-group analyses at the last follow-up. For the assessment of structural outcomes, the Goutallier classification for fatty infiltration (FI) and the tangent sign, occupation ratio, and normalized cross-sectional area for muscle atrophy (MA) were used. The baselines for these structural measurements were both the preoperative and the time-zero MRI scans.
Results:
The mean clinical follow-up period was 31.8 ± 27.5 months, and the MRI follow-up period was 10.9 ± 5.3 months. There were 178 (35.3%), 228 (45.2%), 58 (11.5%), 14 (2.8%), and 26 (5.2%) shoulders with Sugaya grades 1, 2, 3, 4, and 5, respectively. Regardless of structural integrity, all clinical outcomes at a mean follow-up of 31.8 months after repair significantly improved compared with those before repair. Only in shoulders with Sugaya grade 1 did the FI of the supraspinatus muscle improve significantly from baseline. FI of the infraspinatus muscle did not change significantly in those with grades 1 and 2 but worsened in those with grades 3 and 5. MA measured using the occupation ratio improved significantly in shoulders with Sugaya grades 1 and 2 but declined in those with grade 5.
Conclusion:
This study established a correlation between improved structural integrity of the repaired cuff tendon and enhanced structural outcomes in rotator cuff muscles. Furthermore, the findings revealed that both FI and MA could be reversed in patients exhibiting high-quality structural integrity. However, these structural improvements were not mirrored in the clinical outcomes.
Most surgeons agree that the end goal of rotator cuff repair is to restore the structural integrity of the repaired rotator cuff by restoring the anatomy of the footprint with minimal tension and maximum security. However, the clinical implications of structural integrity have been debated for a long time.9,17,22,23 These controversies have arisen because there are some patients who do well with a retear2,17 and some patients who do not do well with healing.8,20 In the majority of extant literature, postoperative evaluation of structural integrity after rotator cuff repair has been bifurcated into 1 of 2 outcomes: healing or retear. 19 Predominantly, these studies use the Sugaya classification, designating grades 1 to 3 as indicative of healing and grades 4 and 5 as retear. However, this dichotomous classification system may not adequately capture the nuanced variations in structural integrity, such as partial healing or partial tears, that are observed clinically. Even as most studies adopt the Sugaya classification 5-tier grading system, they often aggregate these outcomes into 2 broad categories. This oversimplification of subjects of study could potentially obscure more granulated insights into the relationship between the quality of structural integrity and surgical outcomes, a topic that is conspicuously underrepresented in current research.
Beyond clinical measures, the notion of structural outcomes has been introduced as another lens through which to evaluate the success of rotator cuff surgeries. 12 Fatty infiltration (FI) and muscle atrophy (MA) of the rotator cuff muscles are often cited as useful indicators for assessing these structural outcomes. Generally, FI and MA are considered irreversible changes, 5 but some studies suggest the possibility of recovery, especially when the repair is successful.7,12 Contributing to this controversy could be inconsistent preoperative baselines and an inadequate consideration of changes directly attributed to the rotator cuff repair itself. 11 It was demonstrated that variations in outcomes can be influenced not just by structural integrity but also by differing baseline measures, whether preoperative or immediately postoperative.10,16
Therefore, the objective of this study was to investigate the influence of the quality of structural integrity in the repaired cuff tendon on clinical and structural outcomes with segmentation of the integrity group and adoption of the true time-zero baseline. We hypothesized that superior structural integrity in the repaired cuff tendon would result in improved clinical and structural outcomes.
Methods
Patient Inclusion
This retrospective cohort study was approved by our hospital’s institutional review board, and all patients provided informed consent before surgery. The inclusion criteria were (1) arthroscopic rotator cuff repair of a full-thickness rotator cuff tear and (2) presence of preoperative, immediate postoperative, and 1-year postoperative magnetic resonance imaging (MRI) scans. Exclusion criteria were (1) absence of any of the 3 MRI scans, (2) isolated subscapularis repair, (3) pyogenic arthritis, (4) cuff tear arthropathy, (5) revision rotator cuff repair, (6) open repair, and (7) application of platelet-rich plasma.
Between June 2008 and January 2021, 1600 full-thickness rotator cuff tears were treated with arthroscopic rotator cuff repair by a single surgeon (C.H.J.). Among them, 1096 rotator cuff tears were excluded for the following reasons: absence of any of the 3 MRI scans (n = 806), isolated subscapularis tear (n = 29), pyogenic arthritis (n = 39), cuff tear arthropathy (n = 63), revision rotator cuff repair (n = 20), open repair (n = 4), and application of platelet-rich plasma (n = 135). Thus, a total of 504 shoulders in 482 patients (22 patients with bilateral rotator cuff tears) were included in this study (Appendix Figure A1, available in the online version of this article). Shoulders were classified into 5 groups according to the Sugaya classification evaluated using 1-year postoperative MRI. 21
Surgical Procedure and Postoperative Protocol
All conventional repair procedures were carried out by a single surgeon with the patient in the lateral decubitus position under general anesthesia as previously detailed (Appendix, available online). 6 The goal of repair was to cover as much of the greater tuberosity as possible, without excessive tension. We divided tendon excursion into 4 grades based on the extent to which the torn end covered the greater tuberosity by pulling it with a tissue retriever before any tendon-mobilizing procedure. 6 In cases in which the excursion of the torn end was found to be insufficient, tendon mobilization procedures were conducted. These included adhesiolysis, superior capsulotomy, coracohumeral ligament release, medialization of the supraspinatus insertion on the greater tuberosity, and pretensioning. The footprint of the greater tuberosity was debrided, and only a minimal layer of mineralized fibrocartilage was removed. Rotator cuff repair was performed using a suture bridge technique. 6 Generally, bioabsorbable anchors with fiberglass sutures were used, and the number of anchors used depended on the tear size: 2 or 3 anchors for small and medium tears and 3 to 5 anchors for large and massive tears. All knots were tied securely using the slippage-proof knot.
Clinical Assessments
All patients completed a standardized outcome assessment questionnaire both preoperatively and 1 year after surgery. Clinical outcomes were evaluated in terms of pain, range of motion (ROM), strength, functional scores, and overall satisfaction and function (Appendix, available online). 12
Structural Assessments With MRI
MRI was performed using a 3.0-T scanner (Achieva3.0T; Philips Medical Systems) equipped with a dedicated shoulder coil. These scans were conducted preoperatively as well as at 3 days and 1 year postoperatively. 10 The quality of structural integrity was evaluated and classified using Sugaya classification. 21 Grades 1 to 3 were considered as healing, whereas grades 4 and 5 were considered as retear. Each patient was grouped into 1 of 5 groups according to his or her own Sugaya grade. FI was assessed using the Goutallier grade as modified by Fuchs et al 3 and the global fatty degeneration index (GFDI). MA was assessed using the modified tangent sign, the occupation ratio, and a normalized cross-sectional area (nCSA) of the supraspinatus muscle (the ratio of the CSA of the supraspinatus muscle to the CSA of the bony supraspinatus fossa). 12 Two orthopaedic surgeons (J.L. and K.K.) blinded to the information from the MRI scans measured all the variables in this study. If there was a discrepancy, a consensus was reached after discussion. Changes in each measure between the immediate postoperative baseline and 1 year after surgery, and between the preoperative baseline and 1 year after surgery were calculated.
Statistical Analysis
Continuous variables were compared between groups using the Kruskal-Wallis test followed by the Dunn test with Bonferroni correction for pairwise comparisons. For categorical variables, the chi-square test or Fisher exact test was used. The Wilcoxon signed-rank test or McNemar test was utilized for within-group comparisons. Using preoperative, immediate postoperative, and 1-year postoperative MRI scans, we evaluated structural changes of rotator cuff muscles within and/or between groups according to Sugaya classification using a generalized linear model for repeated measures. All analyses were conducted with SAS (Version 9.4; SAS Institute Inc) and P <.05 was considered statistically significant.
Results
Patient Characteristics
The characteristics of the patients are presented in Table 1. There were 188 (37.3%) and 316 (62.7%) shoulders of male and female patients, respectively, with a mean age of 63.1 ± 7.7 years. There were 178 (35.3%), 228 (45.2%), 58 (11.5%), 14 (2.8%), and 26 (5.2%) shoulders with Sugaya grades of 1, 2, 3, 4, and 5, respectively. The 5 groups exhibited similar ages, sex distributions, and symptom aggravation period before surgery (P > .05), but showed significant differences in symptom durations and limb dominance (P < .001). For structural findings, the modified tangent sign, occupational ratio, Goutallier grades of the supraspinatus and infraspinatus muscles, and GFDI showed significant differences between the groups (all P < .001). The Goutallier grades of the subscapularis and teres minor muscles, as well as all clinical variables, showed no significant differences before surgery. For operative findings, the anteroposterior size (retrogression), mediolateral size (retraction), tendon grade, lateral excursion, and greater tuberosity coverage of the torn end were significantly different between the groups (all P < .001). The mean clinical follow-up period was 31.8 ± 27.5 months, and the MRI follow-up period was 10.9 ± 5.3 months. There were no significant differences with respect to the clinical follow-up and MRI follow-up durations among the 5 groups (P > .05).
Patient Characteristics With Respect to Quality of Integrity a
Data are presented as mean ± SD or n (%). GT, greater tuberosity; nCSA, normalized cross-sectional area; S, small; M, medium; L, large, MSV, massive.
Clinical Outcomes With Respect to Quality of Structural Integrity
Pain
All visual analog scale pain measures demonstrated a significant decrease at the final follow-up after surgery, across all Sugaya grades, and in both the healing and retear groups (see Appendix Tables A1 and A2, available online). No significant differences were observed in any of the pain measures, either preoperatively or postoperatively, among the 5 grades, or between the healing and retear groups (all P > .05).
Range of Motion
Forward flexion, abduction, and internal rotation significantly improved after surgery in grades 1, 2, and 3; however, these measures remained unchanged in grade 4 (see Appendix Table A1, available online). In grade 5, only forward flexion and abduction showed increases. No significant differences in any ROM measures were noted among the 5 grades, either preoperatively or postoperatively (all P > .05). Similarly, forward flexion, abduction, and internal rotation significantly improved after surgery in both the healing and the retear groups, with no observed differences between these groups (see Appendix Table A2, available online).
Strength
The strength of the supraspinatus, infraspinatus, and subscapularis muscles significantly increased after surgery in grades 1, 2, 3, and 5, as well as in both the healing and the retear groups (see Appendix Table A1, available online). In grade 4, only forward flexion demonstrated a significant improvement. No significant differences in strength measures were observed either preoperatively or postoperatively, nor in the changes among the 5 grades or between the healing and retear groups (see Appendix Table A2, available online).
Functional Scores
The American Shoulder and Elbow Surgeons; Constant; University of California, Los Angeles (UCLA); Disabilities of the Arm, Shoulder and Hand; Simple Shoulder Test; and Shoulder Pain and Disability Index scores demonstrated significant improvements at the last follow-up across all grades and in both the healing and the retear groups (see Appendix Tables A1 and A2, available online). No clinically meaningful differences in these functional measures were observed among the 5 grades, either before or after surgery, nor between the healing and retear groups (see Appendix Table A2, available online). The only statistically significant difference observed was in the changes in UCLA scores among the 5 grades (P = .024).
Overall Satisfaction and Function
Although a statistically significant difference in overall patient satisfaction was observed among the 5 grades at the final follow-up, this disparity seems largely attributable to the grade 4 cohort, which had a limited sample size (n = 14) (see Appendix Table A1, available online). Upon excluding the grade 4 data, the variations in overall satisfaction among the groups were no longer statistically significant.
Overall function significantly improved at the last follow-up across all Sugaya grades and in both the healing and the retear groups (see Appendix Table A2, available online). No clinically meaningful differences in these functional measures were observed among the 5 grades, either before or after surgery, nor between the healing and retear groups.
Structural Outcomes With Respect to Quality of Structural Integrity
Fatty Infiltration
For the supraspinatus muscle, FI seen on the 1-year postoperative MRI scans significantly improved in Sugaya grade 1, remained unchanged in grade 2, and worsened in grades 3 and 5 when compared with the immediate postoperative MRI scans (P = .021, P = .028, and P < .001, respectively) (Figure 1A; Appendix Tables A3 and A4, available online). No significant change was observed in grade 4, likely attributable to the small sample size of shoulders in this category. In contrast, FI remained stable in the healing group between the immediate and 1-year postoperative MRI scans, while it significantly deteriorated in the retear group (P = .500 and P = .001, respectively).
Measurement of fatty infiltration in the supraspinatus muscle using the Goutallier grade (shown by shading) with respect to the quality of integrity evaluated using the Sugaya classification (A, Grade 1; B, Grade 2; C, Grade 3; D, Grade 4; E, Grade 5) and healing status (F, Healing; G, Retear) at the preoperative (PreOP), immediate postoperative (ImPO), and 1-year postoperative (PO1Y) time points in the magnetic resonance imaging scans. The values are given as the number of patients. Gr., grade.
It is noteworthy that FI significantly improved in all Sugaya grades, with the exception of grade 4, when comparing the preoperative and 1-year postoperative MRI scans (Figure 1; Appendix Tables A3 available online). Furthermore, no significant differences were observed either among the various Sugaya grades or between the healing and retear groups (Figure 1; Appendix Table A4, available online).
For the infraspinatus muscle, FI seen on the 1-year postoperative MRI scans remained stable in grades 1, 2, and 4 but worsened in grades 3 and 5 compared with the immediate postoperative MRI scan (P = .028 and P < .001, respectively) (Appendix Tables A3 and A4, available online). In line with this, FI remained consistent in the healing group between the immediate and 1-year postoperative MRI scans, whereas it significantly declined in the retear group (P = .139 and P < .001, respectively). Upon comparison of the preoperative and 1-year postoperative MRI scans, no significant differences were observed either among the various Sugaya grades or between the healing and retear groups.
For the subscapularis muscle, FI seen on the 1-year postoperative MRI scans exhibited significant changes in grades 2 and 5 compared with the immediate postoperative MRI scans (P < .001 and P = .022, respectively), while it remained stable in grades 1, 3, and 4 (Appendix Tables A3 and A4, available online). FI also underwent significant changes in both the healing and the retear groups between the immediate and 1-year MRI scans (P < .001 and P = .005, respectively). When comparing preoperative and 1-year postoperative MRI scans, FI notably changed in grades 2, 4, and 5 (P = .013, P = .041, and P = .017, respectively). Similarly, FI changed significantly in both the healing and retear groups (P = .009 and P = .003, respectively).
For the teres minor muscle, there were no significant changes regardless of Sugaya grade, the 2 baselines for MRI scans, and the structural integrity (Appendix Tables A3 and A4, available online).
When comparing the immediate and 1-year postoperative MRI scans, GFDI remained unchanged in grade 1 but exhibited significant deterioration in grades 2, 3, and 5 (Appendix Tables A3 and A4, available online). Similarly, GFDI significantly worsened in both the healing and the retear groups upon comparison, with a significant difference noted between the 2 groups (P < .001). Conversely, when comparing the preoperative and 1-year postoperative MRI scans, GFDI remained unchanged across all grades. In the healing group, GFDI improved, while it remained stable in the retear group.
Muscle Atrophy
On the 1-year postoperative MRI scans, the tangent sign remained unchanged in Sugaya grade 1 but significantly deteriorated in grades 2, 3, and 5 when compared with the immediate postoperative MRI scans (P = .032, P = .013, and P < .001, respectively) (Appendix Tables A3 and A4, available online). The tangent sign also deteriorated in both the healing and the retear groups (all P < .001). However, when comparing the 1-year postoperative MRI scans with the preoperative MRI scans, the tangent sign presented diverse outcomes; it remained unchanged in grades 1, 4, and 5, while demonstrating significant improvement in grades 2 and 3. Furthermore, the tangent sign improved in the healing group, yet remained unchanged in the retear group.
The occupation ratio seen on the 1-year postoperative MRI scans improved significantly in grades 1 and 2, remained unchanged in grades 3 and 4, and worsened in grade 5 when compared with the immediate postoperative MRI scans (P < .001, P = .001, and P = .004, respectively) (Figure 2; Appendix Tables A3 and A4, available online). In the healing group, the occupation ratio improved; however, it worsened in the retear group (all P < .001). Comparing 1-year postoperative MRI scans with preoperative MRI scans, the occupation ratio significantly improved in grades 1 and 2 but stayed unchanged in grades 3, 4, and 5 (all P < .001). In the healing group, the occupation ratio improved (P < .001), whereas it showed no change in the retear group.
Measurement of muscle atrophy with the occupation ratio in the supraspinatus muscle with respect to the quality of integrity evaluated using the Sugaya classification (A, Grade 1; B, Grade 2; C, Grade 3; D, Grade 4; E, Grade 5) and healing status (F, Healing; G, Retear) at the preoperative (PreOP), immediate postoperative (ImPO), and 1-year postoperative (PO1Y) time points in the magnetic resonance imaging scans. The values are given as the number of patients. Gr., grade.
The nCSA of the supraspinatus muscle seen on the 1-year postoperative MRI scans decreased significantly in a reverse dose-dependent manner with increasing Sugaya grades (all P < .001), with reductions of 8.7%, 11.8%, 19.1%, 22.2%, and 29.2% for grades 1 through 5, respectively (Appendix Tables A3 and A4, available online). In the retear group, the decrease was more pronounced at 26.8% compared with 11.5% in the healing group (P < .001). Conversely, when comparing the 1-year postoperative MRI scans with the preoperative MRI scans, nCSA significantly increased in grades 1 and 2 by 11.6% and 5.2%, respectively (P < .001 and P = .002). No significant difference in nCSA change was observed between the healing and retear groups.
Shoulders That Improved in Both FI and MA Measured With nCSA
In 25 (5%) of 504 shoulders, both FI and nCSA of the supraspinatus muscle improved as seen on the 1-year postoperative MRI scans, compared with the immediate postoperative MRI scans (Table 2). Of these 25 shoulders, 15 (60%) were classified as Sugaya grade 1, 8 (32%) as grade 2, and 2 (8%) as grade 3, with none as grade 4 or 5. In the remaining 479 shoulders, the distribution across the Sugaya grades was as follows: 163 (34.0%) in grade 1, 220 (45.9%) in grade 2, 56 (11.7%) in grade 3, 14 (2.9%) in grade 4, and 26 (5.4%) in grade 5.
Distribution of Shoulders That Improved in Both FI and MA Measured With nCSA With Respect to Quality of Integrity a
Data are presented as n (%). FI, fatty infiltration; MA, muscle atrophy; nCSA, normalized cross-sectional area.
Discussion
The most important findings of the study include, first, that the 504 shoulders tested had these Sugaya grades: 178 (35.3%) were grade 1, 228 (45.2%) grade 2, 58 (11.5%) grade 3, 14 (2.8%) grade 4, and 26 (5.2%) grade 5. Retears were found in 40 shoulders, comprising 7.9% of all patients. Regardless of structural integrity, clinical outcomes such as pain, ROM, strength, functional ratings, and patient satisfaction improved significantly at the final follow-up.
Second, structural results varied significantly by integrity, baseline, and rotator cuff type (Table 3, Figures 3 and 4). Comparisons of immediate postoperative and 1-year postoperative supraspinatus MRI scans showed different patterns. FI and MA improved in grade 1, per occupation ratio. MA improved in grade 2, but FI did not. FI worsened while MA stayed constant in grade 3 per occupation ratio. FI and MA declined in grade 5. Comparing preoperative and 1-year MRI scans, FI improved in all grades except grade 4. MA improved to varied degrees in grades 1, 2, and 3 but remained stable in grades 4 and 5. In the healing group, immediate postoperative and 1-year postoperative MRI scans showed varied MA alterations but stable FI. In the retear group, both FI and MA declined. When comparing the preoperative and 1-year postoperative MRI scans, the healing group showed better FI and MA. In the retear group, FI improved while MA differed.
Summary of Changes in FI and MA With Respect to Quality of Integrity and Baseline for Comparison a
FI, fatty infiltration; GFDI, global fatty degeneration index; MA, muscle atrophy.
Results are varied with respect to the occupation ratio, the tangent sign, and the normalized cross-sectional area.
Changes in structural integrity of the torn and repaired rotator cuff tendon with respect to the quality of integrity at the preoperative (PreOP), immediate postoperative (ImPO), and 1-year postoperative (PO1Y) time points.
Changes in fatty infiltration and muscle atrophy of rotator cuff muscles with respect to the quality of integrity at the preoperative (PreOP), immediate postoperative (ImPO), and 1-year postoperative (PO1Y) time points.
Third, comparing immediate and 1-year postoperative MRI scans, infraspinatus FI did not change in grades 1 and 2 but did in grades 3 and 5. The healing group showed an unchanged FI, while the FI of the retear group worsened. When comparing preoperative and 1-year postoperative MRI scans, FI remained unchanged across grades in both the healing and the retear groups. Fourth, GFDI was significantly different from baseline. GFDI decreased in the healing and retear groups with the immediate postoperative MRI scans, but improved in the healing group and remained stable in the retear group with the preoperative MRI scans. Fifth, quantitative nCSA indicated substantial improvements in FI and MA in 25 of the 504 shoulders. These shoulders had a different quality of integrity compared with the other 479: grade 1 in 15 (3.0%), grade 2 in 8 (1.6%), and grade 3 in 2 (0.4%).
Current research suggests that rotator cuff restoration, regardless of structural integrity, has good clinical outcomes, especially in short-term follow-up. More importantly, the findings show that even with a higher quality of integrity, the structural outcomes of rotator cuff muscles are difficult to improve, as evidenced by the decline in the retear group. This study also demonstrated that structural outcomes should be read conservatively when comparing preoperative and 1-year postoperative MRI scans. This study found that 5% of treated shoulders in the healing group had improved structural results. Although these results were not clinically superior in the short term, we anticipate that structural superiority will result in clinical benefits in the long term, potentially guiding future research and clinical practice.
Four factors—patient, disease, surgery, and evaluation—affect clinical results after rotator cuff restoration. Patient considerations include injury history, physical and social activities, comorbidities, expectations, mental health, and workers’ compensation status. Size, retraction, and chronicity of the tear, as well as muscle and bone quality and shoulder joint status, are disease variables. Surgery includes release and repair methods, acromioplasty, anesthetics, and other procedures. The final evaluation criteria are field, instrument, baseline, and group of evaluation. This study examined 2 crucial yet understudied factors: the group and the baseline of the evaluation. Instead of splitting the study patients into healing and retear groups, the authors grouped them into 5 integrity groups for evaluation, making it easier to compare results. We used the immediate postoperative MRI scans instead of the preoperative MRI scans, as it had been demonstrated that lateral excursion could change the appearance of rotator cuff muscles after surgery. 11 To our knowledge, 5 studies have evaluated rotator cuff repair outcomes using segmented integrity groups.14,15,17,20,26 The studies examined small- and medium-sized tears with short-term follow-up and found no significant difference in clinical outcomes, except for a few measures.14,15,17,20,26 The authors concluded that minor tears with limited follow-up made significant differences in clinical outcomes unlikely, although they did not rule out the possibility of differences. The majority of studies did not analyze the structural outcomes of FI or MA, and none used the real time-zero baseline. This investigation found that structural outcomes for FI and MA differed greatly by group and baseline (Table 3; Appendix Table A5, available online). After restoration, the healing group’s supraspinatus muscle FI and MA improved from the preoperative baseline. But from the immediate postoperative baseline representing actual time zero, FI and MA outcomes were variable. This study also demonstrated that only patients with Sugaya grade 1 improved in FI and MA when segmented by integrity. The authors as well as other scientists expect that these structural differences will eventually lead to significant differences between groups in the long term, even though they did not in the short term.9,22,27
The reversibility of FI and MA after repair remains contentious. While the majority of previous authors have reported that neither FI nor MA reverses even with a successful repair in both clinical and experimental studies,1,4,5,13,18,24 some authors have reported that they were reversible or could remain unchanged with integrity. 25 However, all the results of these studies were based on a comparison with the preoperative measurements, which could lead to an inaccurate conclusion, as they did not consider lateral excursion caused by repair.10,11 So far, only 1 experimental study involving continuous musculotendinous traction in sheep has demonstrated the reversibility of both FI and MA. 5 In the current study, the authors found 25 (5%) shoulders showing improvement in both FI and MA when using the immediate postoperative data as the time-zero baseline: 15 (3.0%) with Sugaya grade 1, 8 (1.6%) with grade 2, and 2 (0.4%) with grade 3. This would be the first clinical evidence demonstrating that reversing muscle degeneration with rotator cuff repair is feasible. As robust integrity after repair could only be achieved with good surgical technique, which can be measured with greater tuberosity coverage, 6 the results of this study suggest that the quality of repair leads to the quality of integrity, which in turn leads to the quality of outcomes.
This research has a number of limitations. First, all surgeries were conducted by the same surgeon, with the consistent goal of repair: to cover as much of the greater tuberosity as feasible with secure fixation, yet without tension. This approach presents both advantages and disadvantages. Advantages include the use of a uniform patient care approach and a database management system, which maintains consistency in surgery and follow-up. Disadvantages include the possibility that other surgeons, especially novices, may not replicate the low retear rate. Second, the mean follow-up period (31.8 months) may not be long enough to reveal structural integrity–related clinical outcomes. Third, the Sugaya grades have different sample sizes, especially grade 4 (n = 14), which may affect between-group comparisons. Fourth, selection bias due to the inclusion criteria of the 3 MRI scans, coupled with a potentially inadequate follow-up rate, could be a concern.
Conclusion
This study established a correlation between improved structural integrity of the repaired cuff tendon and enhanced structural outcomes in rotator cuff muscles. Furthermore, the findings revealed that both FI and MA could be reversed in patients exhibiting high-quality structural integrity. However, these structural improvements were not mirrored in the clinical outcomes.
Supplemental Material
sj-pdf-1-ajs-10.1177_03635465241255944 – Supplemental material for Effects of Quality of Integrity on Clinical and Structural Outcomes of Rotator Cuff Repair: A Retrospective Cohort Study of 504 Cases
Supplemental material, sj-pdf-1-ajs-10.1177_03635465241255944 for Effects of Quality of Integrity on Clinical and Structural Outcomes of Rotator Cuff Repair: A Retrospective Cohort Study of 504 Cases by Chris Hyunchul Jo, Jung-in Lee, Kyunghoon Kim, Eunmi Ahn and Sohee Oh in The American Journal of Sports Medicine
Footnotes
Submitted October 31, 2023; accepted April 17, 2024.
One or more of the authors has declared the following potential conflict of interest or source of funding: This research was supported by a grant (HI20C0386) of the Korea Health Industry Development Institute, a grant (2022R1A2C2092854) of the National Research Foundation of Korea funded by the Korean government, a grant (S3283968) of the Technology Development Program funded by the Ministry of SMEs and Startups (Republic of Korea), and a grant (22C0608L1) of the Korean Fund for Regenerative Medicine funded by the Ministry of Science and ICT and Ministry of Health and Welfare. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
References
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