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Magnetic resonance imaging-detected associated injuries in lateral epicondylitis
*Corresponding author: Haniyya A. Alrehaily, Department of Medical Imaging, King Abdulaziz Medical City, Ministry of National Guard-Health Affairs, Riyadh, Saudi Arabia. dr.haniyya@hotmail.com
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Received: ,
Accepted: ,
How to cite this article: Alrehaily HA, Alharbi RK, Alzahrani AM. Magnetic resonance imaging-detected associated injuries in lateral epicondylitis. J Musculoskelet Surg Res. 2026;10:410-4. doi: 10.25259/JMSR_101_2026
Abstract
Objectives:
The objectives of the study are to report the association between the severity of common extensor tendon (CET) injury and additional elbow abnormalities detected on magnetic resonance imaging (MRI) in patients with lateral epicondylitis.
Methods:
This is a retrospective cross-sectional study that included 144 patients with MRI-confirmed CET injury. Patients with prior elbow surgery, unavailable MRI, or age below 18 years were excluded. Tendon injuries were graded as mild, moderate, or severe. Ligament injuries (lateral ulnar collateral, radial collateral, and medial collateral), muscle injuries, bone injuries, and joint effusion were recorded as present or absent. Associations between tendon injury severity and concomitant abnormalities were analyzed.
Results:
Of 144 patients, 54.9% were female and 63.9% had right-sided involvement. Tendon injuries were mild in 55.6%, moderate in 36.1%, and severe in 8.3%. Concomitant findings included lateral ulnar collateral ligament injury (51.4%), radial collateral ligament injury (18.1%), medial collateral ligament injury (10.4%), muscle injury (9.7%), bone injury (10.4%), and joint effusion (28.5%). Tendon severity was significantly associated with lateral ulnar collateral (p < 0.001), radial collateral (p = 0.002), medial collateral (p < 0.001) ligament injuries, and joint effusion (p = 0.005).
Conclusion:
MRI demonstrated that lateral epicondylitis commonly coexists with ligament and joint abnormalities, and tendon injury severity correlates with ligament injury and joint effusion. Prospective studies are needed to evaluate long-term functional outcomes.
Keywords
Elbow joint
Injuries
Lateral epicondylitis
Magnetic resonance imaging
Pathology
Tendon
Tennis elbow
INTRODUCTION
Lateral epicondylitis, or tennis elbow, is a common musculoskeletal disorder causing lateral elbow pain and functional impairment, typically resulting from degeneration of the common extensor tendon (CET).[1,2] It primarily affects individuals performing repetitive wrist and forearm activities, such as manual labor or racquet sports, and can significantly reduce quality of life and work productivity.[1-3] Clinical diagnosis is based on patient history and physical examination, with pain on resisted wrist extension and tenderness over the lateral epicondyle being characteristic. While ultrasound can assess tendon structure, its sensitivity for detecting concomitant ligamentous, muscular, or osseous injuries is limited.[1,2] In persistent cases, magnetic resonance imaging (MRI) provides a detailed evaluation of soft tissue and bone, enabling identification of associated injuries that may influence prognosis and treatment decisions.[2,3]
Previous studies suggest that CET injury may be associated with lateral ulnar collateral ligament (LUCL) abnormalities, potentially leading to more severe or prolonged symptoms.[1-3] Occasional involvement of the radial collateral ligament (RCL), medial collateral ligament (MCL), muscle tears, bone marrow edema, or joint effusion has also been reported, though data remain sparse and often limited by small, heterogeneous cohorts.[1,2,4]
This study aimed to investigate whether the severity of CET injury correlates with additional elbow abnormalities detected on MRI, including ligament, muscle, and bone involvement, as well as joint fluid accumulation. By clarifying these associations, we seek to improve diagnostic accuracy, guide management strategies, and enhance patient care and functional outcomes in lateral epicondylitis.
MATERIALS AND METHODS
This retrospective diagnostic accuracy study was conducted at a single tertiary care center (King Abdulaziz Medical City, National Guard Hospital) and included patients with clinically suspected lateral epicondylitis who underwent MRI between January 2014 and August 2025. A total of 144 patients with MRI-confirmed CET pathology were included. Patients were consecutively identified from the institutional imaging database to minimize selection bias.
Inclusion criteria
Age 18–80 years
Clinical diagnosis of lateral epicondylitis
MRI-confirmed CET abnormalities.
Exclusion criteria
Below 18 years
Prior elbow surgery
Systemic inflammatory conditions
Unavailable or incomplete MRI examinations.
Demographic data, including age, sex, and side of involvement, were obtained from the institutional electronic medical records.
MRI acquisition and evaluation
MRI examinations were performed using a 3 T Philips Ingenia MRI system (Philips Healthcare, Best, The Netherlands) with a small-diameter extremity coil positioned over the elbow. The patient’s elbow was centered in the magnet with the forearm supinated and the elbow extended to optimize visualization of lateral elbow structures.
Multiplanar imaging was acquired in coronal, axial, and sagittal planes using the following sequences: Axial T1-weighted and T2-weighted fat-suppressed (T2FS) sequences, coronal proton density-weighted FS (PD-FS) and short tau inversion recovery (STIR) sequences, sagittal T2FS sequences, and T2-weighted gradient echo sequences for evaluating synovial folds and subtle soft-tissue changes. Slice thickness was 3 mm with an interslice gap of 0.2–0.5 mm and 14 cm field of view. Fat suppression was applied in T2FS, PD-FS, and STIR sequences to enhance soft-tissue contrast, while axial T1-weighted and T2-weighted gradient echo images were acquired without fat suppression.
This protocol enabled high-resolution assessment of the CET; lateral collateral ligament complex; and associated muscular, osseous, and joint abnormalities in patients with lateral epicondylitis, allowing precise evaluation of tendon injury, ligamentous compromise, joint effusion, and subtle soft-tissue changes.[5]
Injury grading was performed using the Kraushaar and Nirschl tendinosis classification system, and the grading criteria are summarized in Table 1.[6]
| Grade | Imaging findings | Description |
|---|---|---|
| Mild | Tendon thickening with an internal focal increased signal on fat-suppressed T2-weighted images | Indicates early tendinopathy without significant fiber disruption |
| Moderate | Fluid-filled gap involving 20–80% of tendon thickness | Suggests partial-thickness tendon tear |
| Severe | Fluid-filled gap involving >80% of tendon thickness | Represents near- complete or high-grade tendon tear |
Concomitant injuries were assessed and categorized as either present or absent. These included ligamentous injuries involving the LUCL, RCL, and MCL; muscular involvement of the extensor muscle group [Table 2]; associated osseous lesions, such as bone marrow edema, contusions, or fractures; and joint effusion.[1-3]
| Age (years) | Mean (Standard deviation) | 48.01 (9.763) | |
|---|---|---|---|
| Minimum-Maximum | 22–73 | ||
| Parameters | Category | Number | Percentage |
| Sex | Male | 65 | 45.1 |
| Female | 79 | 54.9 | |
| Lesions side | Right | 92 | 63.9 |
| Left | 52 | 36.1 | |
| Common extensor tendon injury | Mild | 80 | 55.6 |
| Moderate | 52 | 36.1 | |
| Severe | 12 | 8.3 | |
All MRI examinations were interpreted by musculoskeletal consultant radiologists as part of routine clinical practice. Imaging findings were retrospectively extracted from the finalized radiology reports available in the institutional database, and no additional independent image review was performed for the purposes of this study. Demographic data for each patient were retrieved from the hospital’s electronic medical records and entered into a Microsoft Excel spreadsheet [Table 2]. The dataset was reviewed and verified to ensure accuracy and completeness before statistical analysis.
Statistical analysis
Categorical variables were reported as counts and percentages, and continuous variables as mean ± standard deviation (range). Associations between CET injury severity and concomitant MRI findings were assessed using Chi-square tests. For diagnostic accuracy measures, sensitivity, specificity, positive predictive value, and negative predictive value were calculated with 95% confidence intervals. Statistical significance was defined as p< 0.05. All analyses were performed using the Statistical Package for the Social Sciences.
RESULTS
A total of 144 patients were included, comprising 79 females (54.9%) and 65 males (45.1%), with right-sided involvement in 92 cases (63.9%). CET injuries were graded as mild in 80 patients (55.6%), moderate in 52 patients (36.1%), and severe in 12 patients (8.3%).
Concomitant structural abnormalities identified on MRI included ligamentous, muscular, bony, and joint involvement. The LUCL was injured in 74 patients (51.4%), the RCL in 26 (18.1%), and the MCL in 15 (10.4%). Muscle injuries were present in 14 patients (9.7%), bone lesions in 15 patients (10.4%), and joint effusion in 41 patients (28.5%) [Figure 1, Table 3].
| Parameters | Category | Number | Percentage |
|---|---|---|---|
| Lateral ulnar collateral ligament injury | Yes | 74 | 51.4 |
| No | 70 | 48.6 | |
| Radial collateral ligament injury | Yes | 26 | 18.1 |
| No | 118 | 81.9 | |
| Medial collateral ligament injury | Yes | 15 | 10.4 |
| No | 129 | 89.6 | |
| Muscle injury | Yes (high signal intensity) | 14 | 9.7 |
| No | 130 | 90.3 | |
| Bone injury | Yes (high signal intensity) | 15 | 10.4 |
| No | 129 | 89.6 | |
| Joint effusion | Yes (the fluid increased) | 41 | 28.5 |
| No | 103 | 71.5 |
No additional statistical analyses were performed for muscle or bone injuries due to the limited sample size.
DISCUSSION
Our study demonstrates that lateral epicondylitis, traditionally considered a tendinopathy of the CET, frequently involves concomitant ligamentous, muscular, osseous, and joint abnormalities that correlate with the severity of tendon injury, as shown in Figures 2 and 3. In this cohort of 144 patients, the LUCL was the most commonly affected structure, observed in over half of the patients, and strongly associated with severe tendon damage. RCL and MCL injuries, although less frequent, also showed a significant correlation with the severity of tendon damage. Joint effusion was identified in nearly 30% of patients, while muscle and bone lesions, although less prevalent, were present in patients with moderate-to-severe tendon injury. These findings confirm that structural compromise often extends beyond the tendon in lateral epicondylitis.[1-3]
Unlike many previous investigations, this study systematically evaluated multiple concomitant injuries within a relatively large cohort. Whereas earlier reports primarily focused on isolated LUCL abnormalities or included smaller sample sizes, the current analysis demonstrates a consistent relationship between tendon injury severity and secondary pathology across multiple tissue compartments. These findings provide further insight into the broader spectrum of structural compromise associated with lateral epicondylitis.[2-4,7]
These results align with prior MRI-based studies. Bredella et al. reported LUCL abnormalities in patients with chronic lateral epicondylitis, suggesting that chronic tendinopathy may predispose adjacent ligaments to secondary injury.[2] Similarly, Saeki et al. found that the CET is rarely the sole affected structure and frequently coexists with other soft-tissue abnormalities around the lateral elbow.[1] Biomechanical evidence further indicates that the close anatomical relationship between the tendon and lateral ligament complex facilitates stress transmission during repetitive wrist extension or forearm rotation, contributing to microtrauma in both tendons and ligaments.[4-8] In addition, joint effusion, observed in nearly one-third of patients, may reflect synovial irritation secondary to chronic tendinopathy or early degenerative changes, consistent with previous reports.[9,10]
From a clinical perspective, these findings highlight the multifactorial nature of lateral elbow pain. Persistent or severe symptoms may not respond adequately to treatments targeting the tendon alone. Ligamentous compromise, particularly of the LUCL, can contribute to subtle joint instability, altered kinematics, and prolonged symptom duration. Recognition of concomitant structural abnormalities has direct clinical implications: It can guide targeted imaging, inform bracing or physiotherapy strategies, and influence surgical decision-making in refractory cases, including consideration of tendon repair versus ligament reconstruction. Furthermore, a comprehensive evaluation of tendon, ligament, and joint involvement using MRI or high-resolution ultrasound may help identify patients at risk of prolonged symptoms.[11,12]
Interventional musculoskeletal radiology plays an increasingly important role in the management of refractory lateral epicondylitis. Image-guided procedures, such as ultrasound-guided percutaneous tenotomy, platelet-rich plasma injections, and corticosteroid injections, allow precise targeting of the degenerated tendon and adjacent pathological tissues while minimizing damage to surrounding structures. These minimally invasive interventions can improve pain and function, accelerate recovery, and serve as effective alternatives to surgery for patients who do not respond to conservative therapy. By providing real-time visualization, interventional procedures enhance procedural accuracy and reduce complication rates. Ultrasound-guided tenotomy and image-guided injections of corticosteroids or biologics have demonstrated favorable outcomes compared with blind injections.[13,14]
Limitations of this study include its retrospective design, which may introduce potential selection bias, and the lack of histopathological correlation, which limits definitive confirmation and characterization of imaging findings.
CONCLUSION
Lateral epicondylitis is frequently associated with ligamentous, muscular, osseous, and joint abnormalities on MRI. The severity of CET injury is significantly correlated with involvement of the lateral ulnar collateral, radial collateral, and MCLs, as well as joint effusion. Recognizing these patterns can improve diagnostic accuracy, guide targeted imaging, and inform management strategies, particularly for patients with persistent symptoms or severe tendon damage, where concomitant injuries may contribute to lateral elbow instability and prolonged recovery.
Recommendations:
(1) Patients with persistent lateral elbow pain or severe tendon injury should undergo MRI evaluation to identify associated ligamentous, muscular, osseous, or joint abnormalities. (2) Recognizing concomitant injuries can guide targeted rehabilitation, bracing, or surgical planning to improve functional outcomes. (3) Future prospective studies with standardized clinical outcomes are recommended to further clarify the impact of associated injuries on recovery and prognosis.
Authors’ contributions:
HAA: Conceptualized and supervised the study and validated the findings; RKA: Developed the methodology, conducted the investigation, performed formal analysis, curated the data, and managed resources; RKA and AMA: Wrote the original draft of the manuscript; HAA: Critically reviewed and edited the manuscript. All authors have critically reviewed and approved the final draft and are responsible for the manuscript’s content and similarity index.
Ethical approval:
This research/study approved by the Institutional Review Board of the King Abdullah International Medical Research Center (KAIMRC), (IRB Approval No.: NRR25/099/12); Study Number: 00000284126; dated: January 28, 2026. The study was conducted in accordance with the Declaration of Helsinki.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of AI-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Conflicts of interest:
There are no conflicting relationships or activities.
Financial support and sponsorship: This study did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
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