Stump classification was correlated with retear in the suture-bridge and double-row repair techniques for arthroscopic rotator cuff repair

Preoperative magnetic resonance imaging rotator cuff tendon stump classification correlates with the surgical outcomes following superior capsular reconstruction

HYPOTHESIS

This study aimed to investigate the correlation between rotator cuff stump classification and postoperative outcomes after superior capsular reconstruction (SCR).

METHODS

A total of 75 patients who underwent SCR between June 2013 and May 2021 were included in this study. Based on stump classification using the signal intensity ratio of the tendon rupture site to the deltoid muscle in the coronal view of preoperative T2-weighted, fat-suppressed magnetic resonance imaging scans, the patients were classified into types 1, 2, and 3 with ratios of <0.8, 0.8-1.3, and >1.3 (44, 17, and 14 patients, respectively). The American Shoulder and Elbow Surgeons (ASES), Constant, and visual analog scale (VAS) scores for pain and range of motion were evaluated at a minimum of 1 year of follow-up postoperatively. The acromiohumeral distance and rotator cuff arthropathy according to the Hamada classification were assessed on plain radiography. The graft integrity was evaluated by magnetic resonance imaging at 3 and 12 months postoperatively and annually thereafter.

RESULTS

Clinical and radiological outcomes were significantly improved after SCR. In comparison with type 2 and 3 patients, type 1 patients had significantly higher ASES scores (type 1, 2, and 3 = 84 ± 10, 75 ± 15, and 76 ± 14; all P = .014), Constant scores (type 1, 2, and 3 = 65 ± 5, 61 ± 9, and 56 ± 13; all P = .005), and forward flexion (type 1, 2, and 3 = 155 ± 10, 154 ± 15, and 145 ± 13; all P = .013). However, these statistical differences between groups were below the established minimum clinically important difference values for the ASES and Constant scores after rotator cuff repair. The graft failure rate after surgery was lower in the type 1 group than that in the other 2 groups; however, the difference was not statistically significant (P = .749).

CONCLUSION

Patients with stump classification type 1 showed significantly better functional scores (ASES and VAS scores) and forward flexion; however, the clinical importance of these differences may be limited. Stump classification may be useful for predicting postoperative clinical outcomes.

Patient, imaging, and surgical factors associated with supraspinatus re-tear pattern after rotator cuff repair

Background

This study aimed to characterize patient, imaging, and surgical factors associated with re-tear patterns after rotator cuff repair, as well as to identify predictors of type 2 failure in a large patient cohort.

Methods

A retrospective case-control study was performed at a single urban academic institution. All patients who underwent an arthroscopic rotator cuff repair by 2 fellowship-trained shoulder and elbow surgeons between 2005 and 2022 and were subsequently found to have a symptomatic re-tear on magnetic resonance imaging were included. Patients were characterized as either a type 1 (failure at bone-tendon interface) or type 2 (failure medial to the bone-tendon junction) re-tear based on the Cho classification. Chart review was performed to collect demographic, imaging, and intraoperative surgical factors. Multivariable analysis was performed to determine patient and imaging factors associated with type 2 failure.

Results

Fifty-seven patients were included in the study. Overall, 33 (57.9%) patients were classified as a Cho 1 re-tear and 24 (42.1%) were classified as Cho 2 re-tear. No differences in preoperative tear characteristics (tear width, tear retraction, and tendon length) or fatty infiltration were found between Cho 1 and Cho 2 re-tears. Bivariate analysis comparing Cho 1 vs. Cho 2 found male sex was associated with a higher incidence of a Cho 2 re-tear (79.2% vs. 20.8%; P = .033). No significant differences in repair construct (single row vs. double row) (P = .816), biceps treatment (P = .552), concomitant subscapularis repair (P = .306), number of medial anchors (P = .533), or number of lateral anchors (P = .776) were noted between re-tear types. After controlling for potential confounding factors, multivariable regression analysis demonstrated that male sex was predictive of developing a Cho 2 re-tear (odds ratio 3.8; 95% confidence interval 1.1-13.3; P = .039). Repair construct was not found to be predictive of re-tear pattern (P = .580).

Conclusion

Repair construct used during rotator cuff repair does not appear to influence re-tear pattern. Male sex was associated with a higher rate of type 2 failure.

Preoperative Increases in T2-Weighted Fat-Suppressed Magnetic Resonance Imaging Signal Intensities Associated With Advanced Tissue Degeneration and Mitochondrial Dysfunction in Rotator Cuff Tears

PURPOSE

To investigate the relationship between magnetic resonance imaging (MRI) signal intensities and mitochondrial function in patients undergoing arthroscopic rotator cuff repair, assessed through histological and genetic profiling of tendon tissue.

METHODS

This study, conducted between April 2022 and January 2023, included 20 patients undergoing rotator cuff repair for atraumatic/degenerative tears. Rotator cuff tendon edge samples were obtained during arthroscopic rotator cuff repair. Patients were classified based on signal intensity from preoperative T2-weighted fat suppressed MRI. Specifically, they were categorized as having either high or low signal intensity at the rotator cuff tendon edge, with the deltoid muscle serving as a reference. Comparative analyses specifically compared the histological features and genetic profiles of the tendon tissue at the rotator cuff tendon edge. Histological evaluation of harvested tendon specimens during arthroscopic rotator cuff repair employed the modified Bonar score. Real-time polymerase chain reaction was used to assess expression of various mitochondrial and apoptosis-related genes. The mitochondrial morphology of the rotator cuff torn site was examined using electron microscopy.

RESULTS

The higher signal intensity group showed significantly higher modified Bonar scores (P = .0068), decreased mitochondrial gene expression, increased TdT-mediated dUTP-biotin nick end labeling-positive cells (P = .032), lower superoxide dismutase activity (P = .011), reduced ATP5A (P = .031), and increased cleaved caspase-9 activity (P = .026) compared with the lower signal intensity group. Electron microscopy revealed fewer mitochondrial cristae in the higher signal intensity group.

CONCLUSIONS

Our results suggest correlations between high MRI signal intensities and the presence of degeneration, mitochondrial dysfunction, and increased apoptosis in rotator cuff tissues. This underscores the utility of MRI signal intensity as an indicator of tissue condition. CLINICAL RELEVANCE: This work builds on the premise that elevated preoperative MRI signal intensities may indicate higher rates of postoperative rotator cuff re-tears, substantiating these findings from a mitochondrial function perspective.

Re-tear after arthroscopic rotator cuff tear surgery: risk analysis using machine learning

BACKGROUND

Postoperative rotator cuff retear after arthroscopic rotator cuff repair (ARCR) is still a major problem. Various risk factors such as age, gender, and tear size have been reported. Recently, magnetic resonance imaging-based stump classification was reported as an index of rotator cuff fragility. Although stump type 3 is reported to have a high retear rate, there are few reports on the risk of postoperative retear based on this classification. Machine learning (ML), an artificial intelligence technique, allows for more flexible predictive models than conventional statistical methods and has been applied to predict clinical outcomes. In this study, we used ML to predict postoperative retear risk after ARCR.

METHODS

The retrospective case-control study included 353 patients who underwent surgical treatment for complete rotator cuff tear using the suture-bridge technique. Patients who initially presented with retears and traumatic tears were excluded. In study participants, after the initial tear repair, rotator cuff retears were diagnosed by magnetic resonance imaging; Sugaya classification types IV and V were defined as re-tears. Age, gender, stump classification, tear size, Goutallier classification, presence of diabetes, and hyperlipidemia were used for ML parameters to predict the risk of retear. Using Python's Scikit-learn as an ML library, five different AI models (logistic regression, random forest, AdaBoost, CatBoost, LightGBM) were trained on the existing data, and the prediction models were applied to the test dataset. The performance of these ML models was measured by the area under the receiver operating characteristic curve. Additionally, key features affecting retear were evaluated.

RESULTS

The area under the receiver operating characteristic curve for logistic regression was 0.78, random forest 0.82, AdaBoost 0.78, CatBoost 0.83, and LightGBM 0.87, respectively for each model. LightGBM showed the highest score. The important factors for model prediction were age, stump classification, and tear size.

CONCLUSIONS

The ML classifier model predicted retears after ARCR with high accuracy, and the AI model showed that the most important characteristics affecting retears were age and imaging findings, including stump classification. This model may be able to predict postoperative rotator cuff retears based on clinical features.

Rotator cuff repair protected with subacromial balloon spacer shows a low rate of non-healing

PURPOSE

The purpose of this study was to evaluate clinical outcomes and tendon integrity on magnetic resonance imaging (MRI) of chronic posterosuperior rotator cuff tears treated with single-row tensionless repair and subacromial balloon spacer as protection with a minimum follow-up of 2 years. The hypothesis of this study was that this procedure would have acceptable clinical outcomes and tendon-healing rate without increased complications.

METHODS

This is a retrospective study of patients with chronic posterosuperior rotator cuff tears repaired with a single-row technique protected with a subacromial balloon device. Patients were followed up for a minimum of 2 years. Clinical outcomes were evaluated with American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) and Numerical Rating Scale (NRS) for pain. MRI study was obtained likewise after at least 2 years to assess tendon-healing rate. Statistical comparison was performed between pre-operative and at least 2-year clinical and imaging follow-up.

RESULTS

Thirty-two patients were included in the study with a mean follow-up of 27 ± 7 (range 24-48). The mean age of this cohort was 58 ± 6 (range 41-66) including 15 males and 17 females. The tear size was on average 2.3 cm (range 2-4) and a mean of 2.1 triple-loaded anchors were used (range 2-3). The ASES score significantly increased from a mean of 39 ± 12 points to a mean of 89 ± 12 at the final follow-up (P < 0.001). Similarly, pain significantly reduced from a mean pre-operative NRS of 6.8 ± 1.4 to 0.8 ± 1.5 at the final follow-up (P < 0.001). MRI scans showed that repair occurred in 26 patients (81.3%). Significant higher ASES score was reached at final follow-up in patients with a "healed" (Sugaya I-III) tendon when compared to patients with an evidence of tendon discontinuity on MRI study (Sugaya IV-V), 93 ± 9 and 74 ± 13, respectively (P < 0.001).

CONCLUSIONS

Arthroscopic repair of chronic posterosuperior rotator cuff tears using a single-row tensionless repair and subacromial spacer as protection resulted in an 81.3% of tendon integrity at a mean follow-up of 27 months. Clinical outcomes and pain scores significantly improved without severe complications reported after a minimum follow-up of 2 years.

LEVEL OF EVIDENCE

III.

Biochemical Markers of Aging (Advanced Glycation End Products) and Degeneration Are Increased in Type 3 Rotator Cuff Tendon Stumps With Increased Signal Intensity Changes on MRI

BACKGROUND

Advanced glycation end products (AGEs) are end products of protein glycation that bind to the receptor for AGEs (RAGE) and activate nicotinamide adenine dinucleotide phosphate oxidase (NOX), resulting in increased oxidative stress and rotator cuff fragility. Stump classification using the signal intensity ratio of the tendon rupture site to the deltoid muscle in the coronal view of T2-weighted fat-suppressed magnetic resonance imaging (MRI) scans is an indicator of clinical outcomes after rotator cuff repair surgery. Comparing the signal intensities of the deltoid (D) and rotator cuff tears (C), Ishitani et al. classified C/D <0.8 as type 1, 0.8 to 1.3 as type 2, and >1.3 as type 3.

HYPOTHESIS/PURPOSE

It was hypothesized that the oxidative stress and collagen degeneration that occur in the rotator cuff due to accumulation of AGEs can be assessed on MRI scans (stump classification). Therefore, this study aimed to compare AGE-related factors in the rotator cuff tear site tissues based on stump classification.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The authors included 30 patients (11 with type 1, 9 with type 2, and 10 with type 3; mean age, 62.3 years) who underwent surgery for complete rotator cuff tears at our hospital. Tendon tissue was harvested from the torn rotator cuff site during surgery for tissue and cell evaluation.

RESULTS

There was no significant difference in the mean age according to stump classification. The number of patients with diabetes was significantly larger in type 3 than in the other types (P < .05). Tissue evaluation showed significantly higher expression of AGE and RAGE staining in type 3 than in the other types (~6.7-fold; P < .01). Cell evaluation showed that the expression rates of reactive oxygen species and apoptosis were significantly higher in type 3 than in the other types (~4.3-fold; P < .01). Gene expression by real-time polymerase chain reaction showed significantly higher RAGE (~5.1-fold), NOX (~5.3-fold), and IL (~3.0-fold) in type 3 than in the other types (P < .05).

CONCLUSION

Stump classification type 3 exhibited the highest accumulation of AGEs and the highest oxidative stress and apoptosis, suggesting a high degree of degeneration and inflammation. Imaging based on stump classification reflects the degeneration and fragility of the torn rotator cuff site.

CLINICAL RELEVANCE

This study provides evidence of a relationship between stump classification, which reflects rotator cuff fragility on MRI, and pathologies related to advanced glycation end products.