Arthroscopic Revision Rotator Cuff Repair: The Role of Previously Neglected Subscapularis Tears

Enhancing Preoperative Diagnosis of Subscapular Muscle Injuries with Shoulder MRI-based Multimodal Radiomics

RATIONALE AND OBJECTIVES

Rotator cuff injury is a common ailment in the musculoskeletal system, with the subscapularis muscle being the largest and most robust muscle of the rotator cuff. The occurrence of subscapularis muscle tears is more frequent than previously reported. The main objective of this research is to harness the power of artificial intelligence to enhance the precision in diagnosing subscapularis muscle injuries via magnetic resonance imaging of the shoulder joint, prior to surgical intervention. This study seeks to integrate advanced artificial intelligence algorithms to analyze magnetic resonance imaging data, aiming to provide more accurate preoperative assessments, which can potentially lead to better surgical outcomes and patient care and promote technological progress in the field of medical imaging analysis.

METHOD

This is a multicenter study that involves 324 patients from a major medical center serving as both the training and testing groups, with an additional 60 patients from two other medical centers comprising the verifying group. The imaging protocol for all these subjects included a series of shoulder magnetic resonance imaging scans: T1-weighted coronal sequences, T2-weighted coronal, axial, and sagittal images. These comprehensive imaging modalities were utilized to thoroughly examine the shoulder joint's anatomical details and to detect any signs of subscapularis muscle damage. To enhance the diagnostic accuracy before surgical procedures, radiomic analysis was employed. This technique involves the extraction of a multitude of quantitative features from the magnetic resonance imaging, which can provide a more nuanced and data-driven approach to identifying subscapularis muscle injuries. The integration of radiomics in this study aims to offer a more precise preoperative assessment, potentially leading to improved surgical planning and patient outcomes.

RESULT

In the course of this study, a comprehensive extraction of 1197 radiomic features was performed for each imaging modality of every patient. The coronal T1-weighted modality, when assessed within the internal verifying cohort, delivered a diagnostic accuracy of 0.766, coupled with an AUC of 0.803. In the case of the T2-weighted modality, the coronal planes exhibited a diagnostic accuracy of 0.781 and an AUC of 0.844. The axial T2-weighted images recorded an accuracy of 0.719 and an AUC of 0.761, while the sagittal T2-weighted images scored an accuracy of 0.766 and an AUC of 0.821. The amalgamation of these imaging techniques through a multimodal strategy markedly enhanced the accuracy to 0.828, with an AUC of 0.916 for the internal verifying group. The diagnostic performance of the coronal T1-weighted modality in the external verifying cohort yielded an accuracy of 0.833, with an area under the curve (AUC) of 0.819. For the T2-weighted modality, the coronal imaging demonstrated an accuracy of 0.767 and an AUC of 0.794. The axial T2-weighted images had an accuracy of 0.783 and an AUC of 0.797, while the sagittal T2-weighted images achieved an accuracy of 0.833 and an AUC of 0.800. When combining the modalities, the multimodal approach significantly improved the accuracy to 0.867, with an AUC of 0.803 in the external verifying group, indicating a robust diagnostic capability.

CONCLUSION

Our study demonstrates that the application of multimodal radiomic techniques to shoulder magnetic resonance imaging significantly enhances the precision of preoperative diagnosis for subscapularis muscle injuries. This approach leverages the comprehensive data provided by various magnetic resonance imaging modalities to offer a more detailed and accurate assessment, which is crucial for surgical planning and patient care.

Heated Tobacco Products Have Detrimental Effects on Rotator Cuff Healing, Similar to Conventional Cigarettes

BACKGROUND

Cigarette smoking impairs rotator cuff healing, but no study, to our knowledge, has focused on the association between heated tobacco products and rotator cuff tears.

METHODS

This study retrospectively investigated 1,133 patients who underwent arthroscopic repair of symptomatic rotator cuff tears between March 2011 and April 2021. Patients were grouped on the basis of their smoking patterns as nonsmokers, cigarette smokers, and heated tobacco smokers. Propensity score matching was used to reduce selection bias, and 45 subjects were selected from each group via 1:1:1 matching. Functional scores and active range of motion were compared among the 3 groups preoperatively and at a 2-year follow-up. Postoperative magnetic resonance imaging was performed 6 months after the surgical procedure to assess structural integrity.

RESULTS

Except for sex, similar baseline characteristics were achieved after propensity score matching. There were no differences in the clinical scores or range of motion between the matched groups either preoperatively or at the 2-year follow-up. However, the retear rate for the matched nonsmoker group was significantly lower (8.9%) than those for the matched cigarette smoker group (31.1%) and the heated tobacco smoker group (28.9%) (p = 0.022). Multivariable logistic regression analysis revealed that the retear rates were 3.403 times higher for the cigarette smoker group and 3.397 times higher for the heated tobacco smoker group than that for the nonsmoker group.

CONCLUSIONS

Heated tobacco users, like conventional cigarette smokers, have worse clinical outcomes with respect to rotator cuff healing than nonsmokers. Regardless of the type of cigarette, abstinence from smoking is necessary for patients undergoing rotator cuff repair surgery.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Outcomes After Revision Arthroscopic Rotator Cuff Repair: A Systematic Review

BACKGROUND

Arthroscopic rotator cuff repair (ARCR) is one of the most commonly performed orthopaedic procedures; however, it is unclear how to manage patients with symptomatic retears.

PURPOSE

To perform a systematic review to evaluate the outcomes of revision ARCR in the literature.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed utilizing the Embase, MEDLINE, and Cochrane Library databases. Eligible for inclusion were clinical studies reporting on revision rotator cuff repair. Clinical outcomes were recorded.

RESULTS

The 17 included studies were composed of 888 shoulders in 885 patients. The mean age of the 885 patients was 58.6 ± 9.1 years, with a mean follow-up of 28.1 ± 22.1 months. The mean visual analog scale score was 2.1 ± 1.8, the mean American Shoulder and Elbow Surgeons score was 75.0 ± 18.3, and the mean Constant score was 67.4 ± 16.6. The overall rate of retears after revision was 25.3%, with an 8.0% reoperation rate including 2.7% undergoing reverse shoulder arthroplasty and 2.0% undergoing subsequent rotator cuff repair. Finally, the complication rate was 8.6%.

CONCLUSION

Revision ARCR improved patient-reported outcomes, with 92% of patients free from reoperations at a mean follow-up of 2 years. Overall, 78.4% of patients were satisfied at final follow-up; however, the rate of retears was found to be higher than after primary ARCR.

Arthroscopic Modified Subacromial Viewing Portal Repair of Upper Third of Subscapularis Tendon Partial-Thickness Tears

At present, the repair pattern of upper third of subscapularis tendon partial-thickness tears (upper-third tendon tears) is performed in the glenohumeral joint and conventional subacromial viewing portal, but the visualization of subscapularis tendon and footprint is poor when using a 30° scope. The modified subacromial viewing portal presented in this Technical Note is a modified surgical technique for the repair of upper-third tendon tears. Since the scope forms an angle of 70° with the subscapularis tendon and footprint of lesser tuberosity, satisfactory visualization can be obtained when using 30° scope; the predesigned surgical portal and working space without bony barrier can offer a smooth surgical procedure. Our surgical technique is described in pearls, pitfalls, advantages, and disadvantages.

Editorial Commentary: Artificial Intelligence Models Using Machine Learning Can Improve Preoperative Identification of Subscapularis Pathology

Subscapularis pathology is difficult to diagnose, in part because of decreased sensitivity and accuracy in identifying tears with magnetic resonance imaging (MRI) when compared to other cuff tendons. Artificial intelligence evaluation of patient physical examination and MRI data using a machine learning model shows that arthroscopically confirmed partial- or full-thickness subscapularis tears are highly associated with abnormal subscapularis tendon length, long head of the biceps tears, and subscapularis fatty atrophy, and on physical examination, with weakness with internal rotation and positive lift-off, belly press, and bear hug tests. Today, physicians may use machine learning as a tool, but this model may not currently be sufficient to drastically change practice. However, with continued research and development, which is occurring rapidly, similar models could aid physicians in timely identification of pathology and optimization of preoperative planning, as well as physician training and education.

A Machine Learning Model Demonstrates Excellent Performance in Predicting Subscapularis Tears Based on Pre-Operative Imaging Parameters Alone

PURPOSE

To develop a machine learning model capable of identifying subscapularis tears before surgery based on imaging and physical examination findings.

METHODS

Between 2010 and 2020, 202 consecutive shoulders underwent arthroscopic rotator cuff repair by a single surgeon. Patient demographics, physical examination findings (including range of motion, weakness with internal rotation, lift/push-off test, belly press test, and bear hug test), and imaging (including direct and indirect signs of tearing, biceps status, fatty atrophy, cystic changes, and other similar findings) were included for model creation.

RESULTS

Sixty percent of the shoulders had partial or full thickness tears of the subscapularis verified during surgery (83% of these were upper third). Using only preoperative imaging-related parameters, the XGBoost model demonstrated excellent performance at predicting subscapularis tears (c-statistic, 0.84; accuracy, 0.85; F1 score, 0.87). The top 5 features included direct signs related to the presence of tearing as evidenced on magnetic resonance imaging (MRI) (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology.

CONCLUSIONS

In this study, machine learning was successful in predicting subscapularis tears by MRI alone in 85% of patients, and this accuracy did not decrease by isolating the model to the top features. The top five features included direct signs related to the presence of tearing as evidenced on MRI (changes in tendon morphology and signal), as well as the quality of the MRI and biceps pathology. Last, in advanced modeling, the addition of physical examination or patient characteristics did not make a significant difference in the predictive ability of this model.

LEVEL OF EVIDENCE

Level III, diagnostic case-control study.

The influence of rotator cuff tear type and weight bearing on shoulder biomechanics in an ex vivo simulator experiment

Glenohumeral biomechanics after rotator cuff (RC) tears have not been fully elucidated. This study aimed to investigate the muscle compensatory mechanism in weight-bearing shoulders with RC tears and asses the induced pathomechanics (i.e., glenohumeral translation, joint instability, center of force (CoF), joint reaction force). An experimental, glenohumeral simulator with muscle-mimicking cable system was used to simulate 30° scaption motion. Eight fresh-frozen shoulders were prepared and mounted in the simulator. Specimen-specific scapular anthropometry was used to test six RC tear types, with intact RC serving as the control, and three weight-bearing loads, with the non-weight-bearing condition serving as the control. Glenohumeral translation was calculated using instantaneous helical axis. CoF, muscle forces, and joint reaction forces were measured using force sensors integrated into the simulator. Linear mixed effects models (RC tear type and weight-bearing) with random effects (specimen and sex) were used to assess differences in glenohumeral biomechanics. RC tears did not change the glenohumeral translation (p > 0.05) but shifted the CoF superiorly (p ≤ 0.005). Glenohumeral translation and joint reaction forces increased with increasing weight bearing (p < 0.001). RC and deltoid muscle forces increased with the presence of RC tears (p ≤ 0.046) and increased weight bearing (p ≤ 0.042). The synergistic muscles compensated for the torn RC tendons, and the glenohumeral translation remained comparable to that for the intact RC tendons. However, in RC tears, the more superior CoF was close to where glenoid erosion occurs in RC tear patients with secondary osteoarthritis. These findings underscore the importance of early detection and precise management of RC tears.

Clinical Approach to Inconclusive Subscapularis Tear Diagnosis: a Meta-analysis

To identify factors associated with subscapularis (SSC) tears and provide a theoretical basis for clinical diagnosis, we included studies related to subscapularis tears published before February 1, 2023. We screened for six predictors across previous studies for the meta-analysis. The predictors included age, sex, coracoid overlap (CO), coracohumeral distance (CHD), impairment of the long head of the biceps tendon (LHB), and dominant arm. The Newcastle-Ottawa Scale (NOS) was used to evaluate the quality of the studies. The risk ratios (RRs) and the weighted mean differences (WMDs) were used to evaluate the effect size of categorical variables and continuous variables, respectively. The Egger test was used to assess the publication bias of the studies. Ten studies were included from seven countries. A total of 2 126 patients were enrolled, of whom 1 041 had subscapularis tears and 1 085 did not. The study showed that age (WMD, 4.23 [95% CI, 2.32-6.15]; P<.00001), coracoid overlap (WMD, 1.98 [95% CI, 1.55-2.41]; P<.00001), coracohumeral distance(WMD, -1.03 [95% CI, -1.17- -0.88]; P<.00001), and an injury of the long head of the biceps tendon (RR, 4.98 [95% CI, 3.75-6.61]; P<.00001) were risk factors for subscapularis tears. These risk factors can help clinicians identify subscapularis tears early and select appropriate interventions. The level of evidence is 3.

Long-term results of revision rotator cuff repair for failed cuff repair: a minimum 10-year follow-up study

HYPOTHESIS

Rotator cuff repair remains associated with high retear rates, which range from 13% to 79%. The objective of this study was to evaluate the long-term clinical and structural results after revision rotator cuff repair at a minimum 10-year follow-up.

METHODS

We retrospectively studied the records of all patients who underwent revision rotator cuff repair in 3 different institutions between July 2001 and December 2007 with a minimum 10-year follow-up. A total of 54 patients (61% males, mean age 52 ± 6 years old) met the inclusion criteria. Outcome measures included pain (visual analog scale [VAS]), range of motion (ROM), Subjective Shoulder Value (SSV), and the Constant score. Superior migration, osteoarthritis, and acromiohumeral interval (AHI) were assessed on standard radiographs. Fatty infiltration and structural integrity of the repaired tendon were evaluated on magnetic resonance imaging or computed tomographic arthrogram.

RESULTS

At a mean 14.1 years (10.4-20.5), range of motion did not progress significantly in elevation and internal rotation between pre- and postoperation (158° [range, 100°-180°] to 164° [range, 60°-180°], P = .33, and L3 [range, sacrum-T12] to T12 [range, buttocks-T7], P = .34, respectively) and decreased in active external rotation from 45° (range, 10°-80°) to 39° (range, 10°-80°) (P = .02). However, VAS, SSV, and Constant score were all significantly improved at last follow-up (P < .001). AHI decreased significantly (P = .002) from 10 mm (7-14 mm) to 8 mm (0-12 mm). Two percent of the supraspinatus/infraspinatus tendons were Sugaya 1, 24% were Sugaya 2, 35% were Sugaya 3, 12% were Sugaya 4, and 27% were Sugaya 5. Goutallier score progressed for all muscles, but this did not reach significance and mean Goutallier remained <2 for all 4 muscles at last follow-up. Hamada score progressed from 0% >grade 2 preoperatively to 6% >grade 2 at last follow-up.

CONCLUSION

Revision rotator cuff repair provides significant pain relief and improvement in functional scores at long-term follow-up. The mild progression of fatty infiltration, AHI, and Hamada score suggests that despite high retear rates (39% of stage 4 and 5 in the Sugaya classification), revision repair could possibly have a protective role on the evolution toward cuff tear arthropathy.

Subacromial Balloon Spacer Does Not Reduce the Retear Rate for Massive Rotator Cuff Tears: A Comparative Study

PURPOSE

To determine whether a subacromial spacer decreases the recurrent rotator cuff tear rate in arthroscopically managed massive rotator cuff tears (MRCTs) with 1 year of follow-up.

METHODS

We selected all patients who met the following criteria: (1) an MRCT excluding Collin type A, (2) Goutallier stage equal or less than 2, and (3) complete arthroscopic repair of the MRCT. Patients were allocated into 2 groups: A (without subacromial spacer) or B (with subacromial spacer) for a prospective evaluation 1 year after surgery. The primary outcome was the retear rate, determined with magnetic resonance imaging (MRI) according to the classification of Sugaya. Secondary outcome measures were the functional outcomes using visual analog score, Shoulder Subjective Value, and Constant-Murley Score. Preoperative rotator cuff characteristics such as number of tendons involved and the tear retraction also were evaluated. Patient-related data such as sex, age, laterality, history of smoking, and diabetes mellitus were analyzed.

RESULTS

In total, 31 patients were included in group A and 33 in group B. Preoperatively, only 2 differences were found between both groups: a significant (but not clinical) greater Constant score in group A (P = .034) and a slightly greater retraction of the supraspinatus in group B (P = .0025). The overall retear rate between the 2 groups was similar regarding the number of patients (P = .746) and the total number of tendons involved in the recurrent tear (P = .112). At 1-year follow-up, no differences were found in VAS (P = .397), SSV (P = .309), and Constant score (P = .105).

CONCLUSIONS

In reparable massive rotator cuff tears (excluding Collin type A), the augmentation of repair with a subacromial spacer did not significantly reduce the number of patients with recurrent rotator cuff tears identified by MRI. It was also ineffective in reducing the number of re-ruptured tendons in these patients. No patient-reported or clinically significant findings were noted in Constant, SSV, and VAS scores at 1-year postoperative follow-up. Patients with MRI findings of a healed rotator cuff (Sugaya 1-3) had better clinical outcomes compared with those without.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Diagnostic Performance of Belly-Press Angle in Predicting the Severity of Subscapularis Tear

BACKGROUND

Neglected partial subscapularis tears often cause functional impairment even after repair of the supraspinatus and infraspinatus tear is done. Numerous physical examinations for detecting partial subscapularis tears have been described in previous studies.

PURPOSE

To analyze the relationship between the preoperative clinical features and the severity of a partial subscapularis tear and to provide diagnostic clues for patients requiring subscapularis repair.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

This retrospective study included 286 patients who underwent arthroscopic shoulder surgery between 2020 and 2022. Preoperative clinical features, including range of motion, functional scores, muscle strength ratio, modified belly-press test (measuring belly-press angle), and bear-hug test, were collected. Magnetic resonance imaging (MRI) evaluation was done according to the Yoo and Rhee classification. Types of subscapularis tear, supraspinatus lesion, and biceps lesion were recorded during arthroscopic surgery. A comparison of preoperative clinical features between the no-repair group (type 2A or less) and surgical repair group (type 2B or more) was done. The optimal cutoff value of the belly-press angle was determined and the diagnostic performance of the belly-press angle, bear-hug test, and MRI were evaluated using the receiver operating characteristic curve.

RESULTS

Among 286 patients, 189 (66.1%) had subscapularis tears with type 2A or more. There was a significant difference in muscle strength ratio of the belly-press (P < .001), belly-press angle (P < .001), and bear-hug test (P < .001) between the no-repair group (type 2A or less) and the surgical repair group (type 2B or more). With a belly-press angle of 15° as a new cutoff value, the modified belly-press test showed 67.6% sensitivity, 73.9% specificity, and 69.6% accuracy in detecting type 2B or higher subscapularis tear.

CONCLUSION

Patients with type 2A and 2B subscapularis tears (according to the Yoo and Rhee classification) showed differences in belly-press strength ratio, belly-press angle, and bear-hug test. The cutoff value of the 15° belly-press angle showed an accuracy of 69.6% in detecting subscapularis tears with type 2B or higher.

Comparison of the Goutallier Classification of Fatty Infiltration for the Subscapularis With a Novel Modified Classification

Background

Fatty infiltration in the subscapularis muscle extends to the upper portion of the muscle first and then to the lower portion only after some degree of fatty change has taken place in the upper region. Although the Goutallier classification is the most widely used method to categorize fatty infiltration, how to accurately and reliably determine the extent of infiltration is controversial.

Purpose

To examine a modified classification that is more reliable in (1) assessing fatty infiltration of the subscapularis muscle and (2) predicting the structural integrity of the repaired tendon by identifying cutoff points for retear.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Methods

This study retrospectively examined the records of 545 patients who underwent arthroscopic repair for a subscapularis tear. Two shoulder surgeons reviewed the preoperative magnetic resonance imaging scans of all enrolled patients and evaluated the fatty infiltration of the subscapularis muscle based on the original Goutallier classification, as well as a novel modified Goutallier classification designed to measure the proportion of fat and muscle in the upper and lower portions of the muscle separately. Intra- and interobserver agreement of the reviewers was calculated using κ statistics. Using receiver operating characteristic curve analysis, we determined the cutoff point for the particular fatty infiltration grade related to the occurrence of retear for each classification scheme.

Results

The κ values for interobserver reliability were 0.743 and 0.856 for the original and modified Goutallier classifications, respectively, with the modified classification having significantly higher reliability (Z = 4.064; P < .001). Cutoff points for the fatty infiltration grade associated with retear were 2.5 for the original Goutallier classification (sensitivity, 65.3%; specificity, 95.6%; accuracy, 87.8%) and 3.5 for the modified classification (sensitivity, 52.5%; specificity, 97.8%; accuracy, 89.7%).

Conclusion

In assessing fatty infiltration of the subscapularis muscle, the modified Goutallier classification showed higher reliability than the original Goutallier classification. The cutoff point for potential retear (grade 3.5) was at a point where the fatty infiltration extended to the lower portion of the subscapularis muscle.

Subscapularis tendon tears hidden by the medial biceps sling can be missed on arthroscopic examination

INTRODUCTION

To investigate (1) the prevalence of "hidden lesions" and "non-hidden lesions" of subscapularis tendon tears requiring repair during arthroscopic examination that would be missed by a 30° arthroscope, but could be identified by a 70° arthroscope, from the standard posterior portal and (2) the correlation of preoperative internal rotation weakness and findings of magnetic resonance imaging (MRI) indicating hidden lesions.

MATERIALS AND METHODS

We retrospectively examined 430 patients who underwent arthroscopic subscapularis repair between was initially nonvisible with a 30° arthroscope but became visible only with a 70° arthroscope from the standard posterior portal. The preoperative and intraoperative findings of the hidden lesion group (n = 82) were compared with those of the non-hidden lesion group (n = 348). 2016 and 2020. A hidden lesion was defined as a subscapularis tendon tear requiring repair that preoperative internal rotation weakness was assessed using the modified belly-press test. Preoperative MR images were reviewed using a systemic approach.

RESULTS

The prevalence of hidden lesions was 19.1% (82/430). No significant difference was found in preoperative internal rotation weakness between the groups. Preoperative MRI showed a significantly lower detection rate in the hidden lesion group than in the non-hidden group (69.5% vs. 84.8%; P = 0.001). The hidden lesions were at a significantly earlier stage of subscapularis tendon tears than the non-hidden lesions, as revealed by the arthroscopic findings (Lafosse classification, degree of retraction; P = 0.003 for both) and MR findings (muscle atrophy, fatty infiltration; P = 0.001, P = 0.005, respectively).

CONCLUSIONS

Among the subscapularis tears requiring repair, 19.1% could be identified by a 70° arthroscope, but not by a 30° arthroscope, through the posterior portal. The hidden lesions showed a significantly lower detection rate on preoperative MRI than the non-hidden lesions. Thus, for subscapularis tears suspected on preoperative physical examination, the 70° arthroscope would be helpful to avoid a misdiagnosis.

Identifying key factors associated with subscapularis tendon tears and developing a risk prediction model to assist diagnosis

Background

There are still some challenges in diagnosing subscapularis (SSC) tendon tears as accurately as posterosuperior rotator cuff tears on MRI. The omission of SSC tendon tear can lead to muscle atrophy, fatty infiltration, and increased tearing accompanied by aggravated shoulder pain and loss of function. An effective non-invasive evaluation tool will be beneficial to early identification and intervention. The study aims to identify sensitive predictors associated with SSC tendon tears and develop a risk prediction model to assist in diagnosis.

Methods

Data on 660 patients who received shoulder arthroscopic surgery with preoperative shoulder MRI were collected retrospectively. Of these, patients with SSC tendon tears were defined as the SSC tear group, and patients with intact SSC tendon were enrolled in the non-SSC tear group. Logistic regression analysis was used to identify the key predictors of SSC tendon tears which were then incorporated into the nomogram.

Results

Among 22 candidate factors, five independent factors including coracohumeral distance (CHD, oblique sagittal plane) (OR, 0.75; 95%CI, [0.67–0.84]), fluid accumulation (Y-face) (OR, 2.29; 95%CI, [1.20–4.38]), long head of biceps tendon (LHB) dislocation/subluxation (OR, 3.62; 95%CI, [1.96–6.68]), number of posterosuperior (PS) rotator cuff tears (OR, 5.36; 95%CI, [3.12–9.22]), and MRI diagnosis (based on direct signs) (OR, 1.88; 95%CI, [1.06–3.32]) were identified as key predictors associated with SSC tendon tears. Incorporating these predictors, the nomogram achieved a good C index with a good agreement on the risk estimation of calibration plots. Higher total points of the nomogram were associated with a greater risk of SSC tendon tears.

Conclusion

When evaluating the severity of SSC tendon injury, the combination of reliable predictors can improve the sensitivity and diagnostic performance of MRI. This model provides an individualized probability of risk prediction, which is convenient for clinicians to identify patients at high risk for SSC tendon tears to avoid missed diagnosis.