The knee joint is one of the most frequently injured joints in the human body because of its complex anatomy and the substantial biomechanical stresses it experiences during routine activities, trauma, and sports participation. Injuries involving the menisci and cruciate ligaments constitute the majority of cases of internal derangement of the knee and are a major cause of pain, instability, locking, swelling, and functional disability. These injuries predominantly affect young and physically active individuals and, if left untreated, may result in chronic instability, recurrent symptoms, early osteoarthritis, and a considerable socioeconomic burden due to loss of productivity and impaired quality of life. The anatomical configuration and functional demands of the knee make it particularly vulnerable to ligamentous and meniscal injuries. Damage to these structures compromises joint stability, load transmission, shock absorption, and weight-bearing capacity, leading to deterioration of normal knee biomechanics and functional limitation. The menisci play an important role in load distribution, joint lubrication, shock absorption, and proprioception, whereas the anterior and posterior cruciate ligaments serve as the primary stabilizers against abnormal translational and rotational movements of the tibia. Consequently, timely and accurate diagnosis of these injuries is essential to facilitate appropriate treatment and improve long-term functional outcomes. Clinical examination remains the first-line diagnostic approach in patients with suspected internal derangement of the knee. A detailed history combined with specific physical examination tests, including the Lachman, anterior drawer, posterior drawer, pivot shift, McMurray, and Apley's tests, provides valuable information regarding ligamentous and meniscal injuries. However, clinical assessment in the acute setting may be limited by pain, swelling, hemarthrosis, and muscle guarding, potentially reducing diagnostic accuracy. Imaging modalities therefore play an important complementary role in confirming the diagnosis. Conventional radiography and computed tomography are primarily used to identify fractures and associated osseous abnormalities[1], whereas magnetic resonance imaging (MRI) has become the preferred imaging modality for evaluating soft tissue injuries of the knee.[2] MRI offers excellent soft tissue contrast, multiplanar imaging capability, and the advantage of being a non-invasive investigation without exposure to ionizing radiation. It enables detailed assessment of the menisci, cruciate ligaments, collateral ligaments, articular cartilage, and surrounding soft tissues, thereby improving diagnostic confidence and reducing patient morbidity. Nevertheless, MRI is not infallible, and false-positive or false-negative findings may occur because of partial tears, degenerative changes, imaging artefacts, or interpreter variability. Despite these advantages, discrepancies between MRI findings and arthroscopic findings continue to be reported, particularly in meniscal injuries. Previous studies have demonstrated varying degrees of agreement between clinical examination, MRI, and arthroscopy, indicating that each modality possesses distinct strengths and limitations.[3-8] Arthroscopy remains the reference standard for diagnosing internal derangement of the knee because it enables direct visualization of intra-articular structures while simultaneously permitting therapeutic intervention.[9] In addition to its diagnostic value, arthroscopy facilitates immediate management of meniscal tears, ligament injuries, chondral defects, and other intra-articular pathologies, making it an indispensable tool in contemporary orthopedic practice. Although numerous studies have evaluated the diagnostic utility of MRI in knee injuries, considerable variation in the reported diagnostic accuracy, particularly for meniscal lesions, continues to create uncertainty regarding its performance in comparison with careful clinical examination and arthroscopy. Furthermore, prospective studies directly comparing all three diagnostic modalities in the same patient population remain limited. Therefore, the present prospective comparative study was undertaken to compare the diagnostic performance of clinical examination and MRI with arthroscopic findings in patients with internal derangement of the knee, considering arthroscopy as the reference standard. The study also aimed to evaluate the sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy, and agreement of clinical examination and MRI in detecting cruciate ligament and meniscal injuries.

Study Design and Setting: This prospective comparative diagnostic study was conducted in the Department of Orthopaedics, over a period of one year from June 2025 to May 2026. The study was designed to evaluate the diagnostic accuracy of clinical examination and magnetic resonance imaging (MRI) in comparison with arthroscopic findings, with arthroscopy considered the reference standard for diagnosing internal derangement of the knee. Study Population: Patients presenting to the Orthopaedics outpatient department or emergency department with a history suggestive of internal derangement of the knee were screened for eligibility. Thirty-five consecutive patients who fulfilled the inclusion criteria and consented to participate in the study were enrolled. All included patients underwent a comprehensive clinical examination, MRI evaluation, and subsequent diagnostic arthroscopy. Eligibility Criteria: Patients aged 17–60 years presenting with symptoms suggestive of internal derangement of the knee, including pain, instability, locking, or knee effusion, were included in the study. Patients who had undergone MRI because of suspected internal derangement or those with longstanding knee pain and a doubtful history of knee injury were also eligible. Patients were excluded if they had contraindications to MRI, including ferromagnetic implants, pacemakers, or aneurysm clips; active knee joint infection; previous arthroscopic surgery of the affected knee; knee joint neoplasms; inflammatory or infective conditions of the knee; or were younger than 17 years or older than 60 years. Clinical Assessment: Following enrolment, all patients underwent a detailed clinical evaluation performed by an orthopedic surgeon. A comprehensive history was obtained, followed by systematic examination of the affected knee. Clinical assessment included evaluation for joint line tenderness and ligamentous instability using standard orthopedic tests, including the Lachman test, anterior drawer test, posterior drawer test, pivot shift test, McMurray test, Apley's grinding test, and valgus and varus stress tests for assessment of collateral ligament injuries. Routine anteroposterior and lateral radiographs of the affected knee were obtained in all patients to exclude associated bony injuries before further evaluation. Magnetic Resonance Imaging: MRI of the affected knee was performed according to the institutional knee imaging protocol. The examination included multiplanar imaging with localizer sequences in axial, sagittal, and coronal planes, followed by standard knee sequences, including T2-weighted fat-suppressed axial images and sagittal T1-weighted images. MRI findings were recorded for injuries involving the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial and lateral menisci, collateral ligaments, articular cartilage, meniscal cysts, loose bodies, bone contusions, and associated periarticular soft tissue abnormalities. Arthroscopic Evaluation: Following routine preoperative assessment and anesthetic fitness, all patients underwent diagnostic arthroscopy under spinal anesthesia. Arthroscopic examination was performed using standard anterolateral and anteromedial portals, allowing systematic evaluation of the suprapatellar pouch, patellofemoral joint, medial and lateral compartments, medial and lateral gutters, posteromedial and posterolateral compartments, and the intercondylar notch. The presence or absence of injuries involving the ACL, PCL, medial and lateral menisci, collateral ligaments, articular cartilage, and other intra-articular abnormalities was documented. Whenever indicated, appropriate therapeutic procedures, including anterior cruciate ligament reconstruction or partial meniscectomy, were performed during the same procedure. Arthroscopic findings were considered the reference standard for subsequent analysis. Outcome Measures: The primary outcome was to determine the agreement between clinical examination, MRI, and arthroscopic findings for diagnosing cruciate ligament and meniscal injuries. Secondary outcomes included determination of the diagnostic performance of clinical examination and MRI by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), diagnostic accuracy, and agreement with arthroscopic findings. Statistical Analysis: Data were entered into Microsoft Excel for analysis. Continuous variables were expressed as mean ± standard deviation (SD), whereas categorical variables were summarized as frequencies and percentages. Arthroscopy served as the reference standard for calculating diagnostic indices. Sensitivity, specificity, PPV, NPV, and overall diagnostic accuracy of clinical examination and MRI were calculated for ACL, PCL, medial meniscal, and lateral meniscal injuries. Agreement between clinical examination, MRI, and arthroscopic findings was assessed using Cohen's kappa (κ) statistic. Kappa values were interpreted according to the Landis and Koch classification as almost perfect (0.81–1.00), substantial (0.61–0.80), moderate (0.41–0.60), fair (0.21–0.40), slight (0.01–0.20), and poor (0.00). A p-value of less than 0.05 was considered statistically significant..

A total of 35 patients with clinically suspected internal derangement of the knee were included in the study. The mean age of the study population was 29.9 ± 9.9 years (range: 17–57 years). Males constituted 65.7% of the participants, and the right knee was affected more frequently than the left. Road traffic accidents were the most common mechanism of injury, followed by sports-related injuries and falls. Pain was the predominant presenting complaint. The baseline demographic and clinical characteristics of the study participants are presented in Table 1. Table 1. Baseline demographic and clinical characteristics of the study participants (N = 35) Characteristic n (%) / Mean ± SD Age (years) 29.9 ± 9.9 Range 17–57 Age group (years) <20 5 (14.3) 21–30 17 (48.6) 31–40 9 (25.7) 41–50 2 (5.7) >50 2 (5.7) Sex Male 23 (65.7) Female 12 (34.3) Affected knee Right 21 (60.0) Left 14 (40.0) Mode of injury Road traffic accident 16 (45.7) Sports injury 10 (28.6) Fall 9 (25.7) Presenting complaint Pain 26 (74.3) Instability 5 (14.3) Locking 4 (11.4) Arthroscopy identified ACL tears as the most common intra-articular injury (77.1%), followed by medial meniscal tears (68.6%), lateral meniscal tears (22.9%), and PCL tears (2.9%). The frequency of injuries detected by clinical examination, MRI, and arthroscopy is summarized in Table 2. Table 2. Distribution of injuries detected by clinical examination, MRI, and arthroscopy Structure injured Clinical examination n (%) MRI n (%) Arthroscopy n (%) Anterior cruciate ligament 26 (74.3) 26 (74.3) 27 (77.1) Posterior cruciate ligament 1 (2.9) 1 (2.9) 1 (2.9) Medial meniscus 17 (48.6) 19 (54.3) 24 (68.6) Lateral meniscus 6 (17.1) 9 (25.7) 8 (22.9) The diagnostic performance of clinical examination and MRI for detecting ligamentous and meniscal injuries, using arthroscopy as the reference standard, is presented in Table 3. Clinical examination demonstrated higher sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy than MRI for ACL and meniscal injuries. Both clinical examination and MRI correctly identified the single case of PCL injury. Table 3. Diagnostic performance of clinical examination and MRI using arthroscopy as the reference standard Injury Modality Sensitivity (%) Specificity (%) PPV (%) NPV (%) Accuracy (%) Anterior cruciate ligament Clinical examination 96.30 100.00 100.00 88.89 98.15 MRI 88.89 75.00 92.31 66.67 81.94 Posterior cruciate ligament Clinical examination 100.00 100.00 100.00 100.00 100.00 MRI 100.00 100.00 100.00 100.00 100.00 Medial meniscus Clinical examination 70.83 100.00 100.00 61.11 85.42 MRI 62.50 63.64 78.95 43.75 63.07 Lateral meniscus Clinical examination 75.00 100.00 100.00 93.10 94.29 MRI 62.50 85.19 55.56 88.46 73.84 Agreement between each diagnostic modality and arthroscopy is shown in Table 4. Clinical examination demonstrated almost perfect agreement with arthroscopy for ACL and lateral meniscal injuries, whereas substantial agreement was observed for PCL injuries and moderate agreement for medial meniscal injuries. MRI demonstrated substantial agreement for ACL and PCL injuries, moderate agreement for lateral meniscal injuries, and fair agreement for medial meniscal injuries. Table 4. Agreement between clinical examination, MRI, and arthroscopic findings Injury Clinical examination (κ) MRI (κ) Clinical examination p-value MRI p-value Anterior cruciate ligament 0.922 0.612 <0.001 <0.001 Posterior cruciate ligament 0.612 0.612 <0.001 <0.001 Medial meniscus 0.604 0.233 <0.001 0.150 Lateral meniscus 0.822 0.457 <0.001 0.007

The present prospective comparative diagnostic study evaluated the diagnostic performance of clinical examination and magnetic resonance imaging (MRI) using arthroscopy as the reference standard in patients with suspected internal derangement of the knee. Accurate diagnosis of ligamentous and meniscal injuries is fundamental for appropriate treatment planning, prevention of chronic instability, and restoration of normal knee function. The present study demonstrated that clinical examination showed higher diagnostic performance than MRI for anterior cruciate ligament (ACL) and meniscal injuries, whereas MRI demonstrated variable performance, particularly for meniscal lesions. Arthroscopy remained the definitive diagnostic modality for confirming intra-articular pathology. The majority of patients in the present study were young adults, with nearly half belonging to the 21–30-year age group. Males constituted the predominant proportion of the study population, and the right knee was more frequently affected. These findings are comparable with those reported by Fritz et al., who also observed a higher incidence of knee injuries among young, physically active males engaged in sports and other strenuous activities. The predominance of younger patients reflects their greater exposure to high-energy trauma and sporting activities, making them more susceptible to ligamentous and meniscal injuries. ACL tears were the most common injuries identified on arthroscopy, followed by medial meniscal tears. Similar observations have been reported in previous studies, where ACL injuries frequently coexisted with meniscal tears, particularly involving the medial meniscus. Brooks et al. also reported that isolated meniscal injuries were relatively uncommon and that associated ligamentous injuries were frequently identified during arthroscopy, emphasizing the complex nature of internal derangement of the knee.[3,6] Clinical examination demonstrated high diagnostic performance for ACL injuries, with sensitivity of 96.3%, specificity of 100%, and an overall diagnostic accuracy of 98.15%. Only one ACL tear confirmed on arthroscopy was not identified clinically, representing a partially healed tear. These findings reaffirm the importance of meticulous clinical evaluation using established examination techniques such as the Lachman, anterior drawer, and pivot shift tests. Similar conclusions were reported by Rose et al., who demonstrated that an experienced clinical examination provides diagnostic accuracy comparable to MRI for ACL and meniscal injuries. Likewise, Boden et al. suggested that MRI may not significantly influence treatment decisions when clinical findings are unequivocal.[9,10] Although MRI demonstrated good diagnostic performance for ACL injuries, its sensitivity and specificity were lower than those of clinical examination. Two ACL tears confirmed arthroscopically were missed on MRI, while false-positive findings were also observed. Similar limitations have been described in previous studies, where partial ligament tears, mucoid degeneration, chronic injuries, and tears near the femoral or tibial attachment sites resulted in false-positive or false-negative MRI interpretations.[10] Rubin et al. reported MRI sensitivities ranging from 92% to 100% for ACL injuries, with specificity approaching 100%, values slightly higher than those observed in the present study.[11] MRI demonstrated comparatively lower diagnostic performance for meniscal injuries, particularly medial meniscal tears. Reduced sensitivity and specificity were associated with both false-positive and false-negative findings. These observations are consistent with previous reports indicating that degenerative changes, posterior horn tears, radial tears, and anatomical variations may either mimic or obscure meniscal pathology on MRI.[12-19] Elvenes et al. reported an overall MRI accuracy of approximately 84% for meniscal injuries and suggested that its high negative predictive value could reduce unnecessary arthroscopic procedures.[12] In contrast, the lower negative predictive value observed in the present study indicates that MRI alone may not reliably exclude meniscal pathology. Clinical examination demonstrated higher diagnostic performance than MRI for both medial and lateral meniscal injuries. These findings highlight that careful clinical assessment remains indispensable in patients with suspected meniscal pathology. Similar observations have been reported by Rose et al., who found that MRI provided limited additional diagnostic benefit over a thorough clinical examination in patients with clinically evident ACL or meniscal injuries.[10] Conversely, Ruwe et al. advocated the selective use of preoperative MRI in patients with equivocal clinical findings to reduce unnecessary diagnostic arthroscopies.[20]. These observations suggest that MRI should be regarded as a complementary investigation rather than a substitute for clinical examination. MRI correctly identified the single posterior cruciate ligament (PCL) injury confirmed on arthroscopy, resulting in 100% sensitivity, specificity, and diagnostic accuracy. Similar diagnostic performance has been reported in previous studies owing to the characteristic MRI appearance of the intact PCL.[21] However, interpretation of these findings should be made cautiously because only one patient with a PCL injury was included in the present study, limiting the statistical precision and generalizability of this observation. The findings of the present study reinforce that arthroscopy remains the gold standard for diagnosing internal derangement of the knee because of its ability to directly visualize intra-articular structures while simultaneously facilitating therapeutic intervention. MRI remains a valuable non-invasive imaging modality, particularly in patients with equivocal clinical findings, chronic injuries, or suspected multiple ligament involvement. However, the results of the present study indicate that MRI should complement, rather than replace, a comprehensive clinical examination. The present study has certain limitations. It was conducted at a single tertiary care centre with a relatively small sample size, and only one patient had a confirmed PCL injury, limiting the evaluation of MRI performance for this injury. Larger multicentric studies with a broader spectrum of knee pathologies are required to further validate these findings and improve their generalizability.

Accurate diagnosis of internal derangement of the knee is essential for appropriate treatment planning and optimal functional outcomes. In the present study, clinical examination demonstrated higher diagnostic performance than MRI for anterior cruciate ligament and meniscal injuries, whereas both modalities showed excellent diagnostic performance for the single posterior cruciate ligament injury. Although MRI remains a valuable non-invasive imaging modality, it should be interpreted in conjunction with a thorough clinical examination, particularly in patients with suspected meniscal injuries. Arthroscopy continues to be the reference standard for confirming intra-articular knee pathology because of its high diagnostic accuracy and the advantage of simultaneous therapeutic intervention. A systematic approach integrating careful clinical evaluation, selective use of MRI, and arthroscopy when clinically indicated provides the most reliable strategy for the diagnosis and management of internal derangement of the knee.

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