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Magnetic resonance imaging findings of osteoarthrosis and effusion in patients with unilateral temporomandibular joint pain
Int. J. Oral Maxillofac. Surg. 2002; 31: 598–602 doi:10.1054/ijom.2002.0314, available online at http://www.idealibrary.com on
Clinical Paper TMJ Disorders
Magnetic resonance imaging findings of osteoarthrosis and effusion in patients with unilateral temporomandibular joint pain
R. Emshoff1, I. Brandlmaier1, S. Bertram1, A. Rudisch2 1
Department of Oral and Maxillo-Facial Surgery, 2Department of Radiology, University of Innsbruck, A-6020 Innsbruck, Austria
R. Emshoff, I. Brandlmaier, S. Bertram, A. Rudisch: Magnetic resonance imaging findings of osteoarthrosis and effusion in patients with unilateral temporomandibular joint pain. Int. J. Oral Maxillofac. Surg. 2002; 31: 598–602. 2002 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. Abstract. The purpose of this study was to investigate the relationship between the presence of temporomandibular joint (TMJ) pain and the magnetic resonance (MR) imaging findings of osteoarthrosis (OA), and effusion. The study comprised 112 consecutive TMJ pain patients. Criteria for including a patient were report of unilateral pain near the TMJ, with the presence of unilateral TMJ pain during palpation, function, and/or unassisted or assisted mandibular opening. Bilateral sagittal and coronal MR images were obtained to establish the presence or absence of TMJ OA, and/or effusion. Comparison of the TMJ side-related data showed a significant relationship between the clinical finding of TMJ pain and the MR imaging diagnoses of TMJ OA (P=0.000), and TMJ effusion (P=0.000). Further, there was a significant relationship between the MR imaging diagnosis of TMJ OA and TMJ effusion (P=0.000). Use of the Kappa statistical test indicated poor diagnostic agreement between the presence of TMJ pain and the MR imaging diagnosis of TMJ OA (K=0.22), TMJ effusion (K=0.29), and TMJ ‘OA and effusion’ (K=0.30). The study’s findings suggest that while clinical pain is correlated to TMJ-related MR imaging findings, clinical pain in and of itself, is not reliable for predicting the presence of TMJ OA and/or effusion. Validation of MR imaging diagnoses would involve the investigation of cross-sectional and longitudinal evidence to assess decisive differences in terms of prognosis and/or treatment outcome.
Introduction Temporomandibular joint (TMJ) osteoarthrosis (OA) is one of the most common forms of temporomandibular disorders (TMD). The term refers to clinical and radiologic criteria classifying TMJ disorders but is generally used to 0901-5027/02/060598+05 $35.00/0
denote an abnormal osseous morphology of the mandibular condyle and the articular eminence8,27,28. With the rapid progress in TMJ imaging techniques, OA has increasingly been thought to be involved in the development of TMJ pain and dysfunction27,28.
Key words: temporomandibular disorders; orofacial pain; temporomandibular joint osteoarthrosis; magnetic resonance imaging. Accepted for publication 29 June 2002
However, the question of whether TMJ OA may be linked to the onset, progress, or cessation of TMJ-related signs and symptoms remains a point of controversy. TMJ effusion describes the magnetic resonance (MR) imaging finding of
2002 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved.
MRI findings in patients with unilateral temporomandibular joint pain a hyperintensity signal inside the joint space1,21,24,25,30,32,35. W & B emphasized the importance of effusion in MR imaging of the TMJ, and suggested TMJ effusion to represent an inflammatory response to a dysfunctional disk-condyle relationship34. S & W compared retrodiskal tissue intensity in painful and painless TMJs, and found a significant association between TMJ pain and increased signal intensity24. However, A and coworkers, in their article based on a sample of 123 TMJs, failed to relate TMJ pain and TMJ effusion; they described TMJ effusion to be related to the MR imaging finding of internal derangement and osteoarthrosis1. Further, M and associates disclosed that the MR imaging detection of high signal intensity in the closed locking TMJ did not directly relate to the presence of TMJ pain21. These differences in outcome may be related to the diagnostic approach of TMJ-related pain applied in the respective studies. Using MR imaging as a gold standard for the diagnoses of TMJ OA, and effusion, the purpose of the present study was to assess whether in TMJ pain patients, the presence of unilateral TMJ pain may be linked to MR imaging findings of TMJ OA, and/or TMJ effusion. Material and methods The study group consisted of 112 consecutive TMJ patients, referred from medical practitioners and dentists in the community to the Orofacial Pain and TMD Clinic in the Department of Oral and Maxillofacial Surgery at the University of Innsbruck. This clinic is the primary referral centre for TMD at the Institution as both conservative and surgical treatments are offered. There were 97 females and 15 males, aged between 15 and 78 years with a mean age of 38.2 years. The subjects were informed about the study procedure and informed consent was received. Criteria for including a patient were (a) report of orofacial pain referred to the TMJ, (b) presence of unilateral TMJ pain during palpation, during function, and/or during unassisted or assisted mandibular opening, (c) absence of signs and symptoms that characterized a diagnosis of myalgia, (d) no history of trauma, and (e) absence of collagen vascular disease. To determine whether patients classified with unilateral TMJ pain may be linked to MR imaging findings of TMJ
OA and/or TMJ effusion, the subjects underwent clinical and MR imaging investigation. One clinician performed the clinical evaluation on the subject and, every time the patient underwent clinical investigation, MR imaging was performed immediately afterward. With the study being double-blind, the clinical records and images were interpreted by the clinician and medical radiologist independently without knowledge of the results of the other investigator. The MR images were obtained and interpreted prospectively by an experienced radiologist. The clinical assessment consisted of a standardized evaluation of signs and symptoms of TMD, including mandibular range of motion, joint sounds, joint and muscle pain on palpation, and pain on unassisted or assisted mandibular opening37. Mandibular range of motion was evaluated for maximum opening and lateral movements. Maximum opening was measured from central maxillary incisor to the opposing mandibular incisor on a millimetre ruler. Lateral movements were measured relative to the maxillary midline with the teeth slightly separated. The TMJs were auscultated with a stethoscope, with the subject performing three openings, and three lateral and protrusive movements. These were described as single and reciprocal clicks. TMJ pain on palpation was assessed through bilateral manual palpation of the lateral aspect of the condyle. The parameter of TMJ pain during unassisted mandibular opening was assessed by asking the patient to perform maximum voluntary jaw opening. Assisted opening was performed by the application of force to the lower and upper incisors with the middle finger and thumb. A positive pain score was recorded by the examiner if a patient experienced a distinctively painful sensation in the TMJ during the procedure. Pain of the muscles was assessed as positive or negative by a bilateral manual palpation technique. The following sites were palpated: the anterior, posterior, and middle temporalis, the tendon of temporalis, the superficial and deep masseters, the lateral pterygoid, and the anterior and posterior digasric muscle. A diagnosis of myalgia was assigned if palpation produced a clear reaction from the patient, i.e., if the patient experienced a distinctly tender or painful sensation in two or more muscle sites with muscle palpation pain of two or more on a 0 to 3 severity scale34.
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MR imaging was carried out with a 1.5 T MR scanner (Vision, Siemens AG, Erlangen, Germany) and a dedicated circular-polarized transmit-and-receive TMJ coil. The data were collected on a 252256 matrix with a field of view of 145 mm giving a pixel size of 0.600.57 mm. With the patient in a supine position, 15 paracoronal and 8 para-sagittal slices were obtained of each TMJ using a TSE (turbo spin echo)-PD (proton density) sequence (repitition time of 2800 ms, echo time of 15 ms) and a TIRM (turbo inversion recovery magnitude) sequence (repitition time of 4000 ms, echo time of 30 ms, inversion time of 150 ms) with thin slices of 3 mm. MR images were corrected to the horizontal angulation of the long axis of the condyle. Each subject received an individual nonferromagnetic intermaxillary device to obtain the different mouth opening positions. Sequential bilateral T1- and T2-weighted images were made at the closed mouth and the respective maximum mouth opening positions. The T1-weighted images were assesed by the radiologist using established criteria for normal versus osteoarthrotic morphology. OA was defined by the presence of flattening, subchondral sclerosis, surface irregularities, and erosion of the condyle or presence of condylar deformities associated with flattening, subchondral sclerosis, surface irregularities, erosion and osteophyte6,7. On the T2-weighted images, joint effusion was identified as an area of high signal intensity in the region of the joint space (Fig. 1). When more than a line of high signal was evident in at least two consecutive sections, it was considered positive for TMJ effusion35. The TMJ-related MR imaging findings of OA, and effusion were statistically assessed by chi-square analysis. Statistical significance of the diagnostic percent agreement between the clinical findings and MR imaging diagnoses was evaluated using the Kappa statistical test. Significance was set at P<0.05. For all statistical analysis the SPSS package (SPSS Inc., 1997) was used. Results An MR imaging diagnosis of TMJ OA was established in 173 of 224 TMJs (77.2%), while 51 TMJs were found to have an absence of OA (22.8%). In TMJs with pain, 99 of the 112 joints (88.4%) were characterized by the presence of an OA, while in the TMJs without pain, 74 of the 112 joints (66.1%)
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Emshoff et al. agreement between the clinical and the MR imaging findings (Table 3).
Discussion
Fig. 1. Sagittal closed mouth-related MR image shows left TMJ with presence of effusion (arrows), and presence of osteoarthrosis of the condyle, which is flattened and deformed (short arrow).
Table 1. Relationship between MRI diagnosis and TMJ pain (n=224) TMJs Pain side (%) (n=112)
Non-pain side (%) (n=112)
Sum (%) (n=224)
Osteoarthrosis Absence of osteoarthrosis Presence of osteoarthrosis
13 (11.6) 99 (88.4)
38 (33.9) 74 (66.1)
51 (22.8) 173 (77.2)
Effusion Absence of effusion Presence of effusion
58 (51.8) 54 (48.2)
90 (80.4) 22 (19.6)
148 (66.1) 76 (33.9)
MRI diagnosis
MRI, magnetic resonance imaging; TMJ, temporomandibular joint; (%), percent; n, number of TMJs.
showed an abnormal morphology. Analysis of side-related data showed a significant relationship between the clinical finding of TMJ pain and the MR imaging diagnoses of TMJ OA (2 =15.868, df=1, P=0.000) (Table 1). TMJ effusion was observed in 76 of 224 TMJs (33.9%). In TMJs with pain, 54 of the 112 joints (48.2%) were characterized by the presence of effusion, while in the TMJs without pain, 22 of the 112 joints (19.6%) showed an abnormal relationship. There was a significant correlation between the clinical finding of TMJ pain and the MR imaging diag-
nosis of TMJ effusion (2 =20.393, df=1, P=0.000) (Table 1). MR imaging showed effusion in 5 (9.8%) of the TMJs with an absence of OA, and 71 (41.0%) of the TMJs with OA. There was a significant relationship between the MR imaging finding of TMJ effusion and those of TMJ OA (2 =17.144, df=1, P=0.000) (Table 2). Comparing the agreement between the presence of TMJ pain and the MR imaging diagnoses of OA and effusion, the TMJ group K-values for OA, effusion, and ‘OA and effusion’ rated 0.22, 0.29, and 0.30 respectively, indicating poor
This study confirms MR imaging to be a valuable diagnostic method for measuring local TMJ-related signs of OA3,10,16,27,33. Regarding the prevalence of TMJ OA (77.2%), the findings correspond to the reports of other authors who described frequencies of imaging signs of TMJ OA in TMD patients as ranging from 11.4% to 58%3,10,17,18,36. The finding of a significant relationship between structural TMJ OA changes and TMJ-related findings of pain may contrast the results of several authors reporting high prevalences of radiographic signs of OA in asymptomatic TMJs ranging from 50% to 90%4,11,36. However, the fact that prevalences of TMJ OA are reported with great variations in the literature, and that multiple-factor studies using specific clinical and imaging criteria for diagnosing TMJ OA are still lacking, indicates the neccessity for further investigations to test the hypothesis that TMJ-related TMD patients with specific clinical symptoms do not differ from control subjects with regard to the presence of specific imaging signs of TMJ OA5. The results of MR imaging in the present study showed TMJ pain to be associated with a high rate of TMJ effusion (48.2%). This observation compares favourably with the results of other authors reporting prevalences of TMJ effusion in TMJs with pain ranging from 13% to 88%21,25, 30. while prevalence rates in TMJs without pain have been described as ranging from 0% to 38.5%30,35. TMJ effusion was more frequently observed in TMJ OA (41.0%) than in TMJs without OA (9.8%). Further, there was a significant relationship between the finding of TMJ effusion and those of TMJ OA. These results may be regarded as comparable with those of a previous study describing a significant association between MR imaging diagnoses of TMJ OA and effusion; it showed OA to occur primarily in TMJs with effusion, the reported prevalences ranging from 13% for absence of OA to 38% for OA1. The findings of a significant relationship between the presence of TMJ pain and the MR imaging diagnoses of TMJ effusion are in agreement with those of some authors suggesting TMJ effusion to represent an inflammatory response
MRI findings in patients with unilateral temporomandibular joint pain Table 2. Relationship between MRI diagnosis of TMJ effusion and TMJ osteoarthrosis (n=224) TMJs MRI diagnosis Absence of osteoarthrosis Presence of osteoarthrosis Sum
Presence of effusion (%)
Absence of effusion (%)
Sum (%)
5 (9.8) 71 (41.0) 76 (33.9)
46 (90.2) 102 (59.0) 148 (66.1)
51 (100) 173 (100) 224 (100)
MRI, magnetic resonance imaging; TMJ, temporomandibular joint; n, number of TMJs; (%), percent. Table 3. Diagnostic agreement between clinical finding of TMJ pain and MRI diagnoses of TMJ osteoarthrosis, and effusion in patients with unilateral TMJ pain (n=224)
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may show decisive differences in the areas of pathogenesis, treatment and/or prognosis. The study’s findings suggest that while clinical pain is correlated to TMJ-related MR imaging findings, clinical pain in and of itself, is not reliable for predicting the presence of TMJ OA and/or effusion. Validation of MR imaging diagnoses would involve the investigation of crosssectional and longitudinal evidence to assess decisive differences in terms of prognosis and/or treatment outcome.
MRI diagnosis TMJ pain group % Diagnostic agreement K-value*
Osteoarthrosis
Effusion
‘Osteoarthrosis and effusion’
61.2 (n=137) 0.22
64.3 (n=144) 0.29
64.7 (n=145) 0.30
TMJ, temporomandibular joint; MRI, magnetic resonance imaging; n, number of TMJs; (%), percent; *K-value: 0–0.2, no reliability; 0.2–0.4, poor reliability; 0.4–0.6, fair reliability; 0.6–0.8, good reliability; and 0.8–1.0, excellent reliability.
to a dysfunctional TMJ24,35, while others failed to correlate the MR imaging detection of effusion to the presence of TMJ pain1,21. These differences may be related to the diagnostic approach of TMD and TMJ-related pain applied in the respective studies. Using strict inclusion and exclusion criteria to define homogeneous TMJ pain groups, further studies including a large sample size of TMD patients and non-TMD subjects may be warranted to describe TMJ pain specific data on TMJ side-related prevalences of ID, and effusion. The study revealed an unacceptable level of agreement between the clinician in his finding of TMJ pain and the radiologist in his corresponding MR imaging diagnoses of OA, effusion, and ‘OA and effusion’. Several authors investigated the reliability of clinical items for TMJ OA using arthrography and MR imaging as a ‘gold standard’. The clinical predictions of OA were validated by arthrography and MR imaging in 35% and 67%, respectively10,17,22. With the additional use of tomographic films prior to arthrography the diagnostic agreement even was described with 95% and 100%2. This would seem to support the concept, that beside clinical joint crepitus and/or grating, the diagnosis of osteoarthrosis is primarily a radiographic diagnosis5. Several studies have focused on the importance of degenerative changes as the underlying mechanism in the aetiology of TMJ-related pain and dysfunction12,13–27. Arthroscopic studies have confirmed the concept that inflammatory processes of the synovium, cap-
sule, or retrodiscal tissues are the underlying mechanisms for the occurrence of TMJ-related pain38, while divergent correlations were found between local arthroscopic and light microscopic signs of inflammation. Factors like direct mechanical injury, hypoxiaperfusion, and neurogenic inflammation were regarded as aetiologic in the production of synovitis, cartilage degeneration, and osteoarthritis19,20. The introduction of TMJ synovial fluid analysis has enhanced the knowledge of the underlying biochemical events that contribute to the pathologic conditions of the TMJ. Biochemical investigations of the TMJ synovial fluid in combination with arthroscopic evaluation of the morphologic appearance of the cartilage and synovium have suggested a significant relationship between osteoarthritis and synovitis14,15,38, and an important role of cytokines in TMJ pain and dysfunction by taking part in the mediation of acute and chronic inflammation and associated connective tissue destruction9,23,26,31. The findings raise the question of whether the use of clinical TMJ-related diagnoses may need to be supplemented by MR imaging to distinguish among subtypes of TMJ disorders. From a methodological point of view, aetiology, prognostic statements, and implications for treatment are considered to be the main indicators for the utility of diagnostic classifications29. Further research may be warranted to assess the diagnostic validity of MR imaging-related variables of TMJ OA, and effusion by determining how well these diagnoses
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Address: Dr Ru¨diger Emshoff Ho¨henstraße 5 A-6020 Innsbruck Austria Tel.: 0043/512/276661 Tel.: 0043/512/504/4373 Fax: 0043/512/504/4371 E-mail: Ruediger–Emshoff@hotmail.com
Clinical Paper TMJ Disorders
Magnetic resonance imaging findings of osteoarthrosis and effusion in patients with unilateral temporomandibular joint pain
R. Emshoff1, I. Brandlmaier1, S. Bertram1, A. Rudisch2 1
Department of Oral and Maxillo-Facial Surgery, 2Department of Radiology, University of Innsbruck, A-6020 Innsbruck, Austria
R. Emshoff, I. Brandlmaier, S. Bertram, A. Rudisch: Magnetic resonance imaging findings of osteoarthrosis and effusion in patients with unilateral temporomandibular joint pain. Int. J. Oral Maxillofac. Surg. 2002; 31: 598–602. 2002 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. Abstract. The purpose of this study was to investigate the relationship between the presence of temporomandibular joint (TMJ) pain and the magnetic resonance (MR) imaging findings of osteoarthrosis (OA), and effusion. The study comprised 112 consecutive TMJ pain patients. Criteria for including a patient were report of unilateral pain near the TMJ, with the presence of unilateral TMJ pain during palpation, function, and/or unassisted or assisted mandibular opening. Bilateral sagittal and coronal MR images were obtained to establish the presence or absence of TMJ OA, and/or effusion. Comparison of the TMJ side-related data showed a significant relationship between the clinical finding of TMJ pain and the MR imaging diagnoses of TMJ OA (P=0.000), and TMJ effusion (P=0.000). Further, there was a significant relationship between the MR imaging diagnosis of TMJ OA and TMJ effusion (P=0.000). Use of the Kappa statistical test indicated poor diagnostic agreement between the presence of TMJ pain and the MR imaging diagnosis of TMJ OA (K=0.22), TMJ effusion (K=0.29), and TMJ ‘OA and effusion’ (K=0.30). The study’s findings suggest that while clinical pain is correlated to TMJ-related MR imaging findings, clinical pain in and of itself, is not reliable for predicting the presence of TMJ OA and/or effusion. Validation of MR imaging diagnoses would involve the investigation of cross-sectional and longitudinal evidence to assess decisive differences in terms of prognosis and/or treatment outcome.
Introduction Temporomandibular joint (TMJ) osteoarthrosis (OA) is one of the most common forms of temporomandibular disorders (TMD). The term refers to clinical and radiologic criteria classifying TMJ disorders but is generally used to 0901-5027/02/060598+05 $35.00/0
denote an abnormal osseous morphology of the mandibular condyle and the articular eminence8,27,28. With the rapid progress in TMJ imaging techniques, OA has increasingly been thought to be involved in the development of TMJ pain and dysfunction27,28.
Key words: temporomandibular disorders; orofacial pain; temporomandibular joint osteoarthrosis; magnetic resonance imaging. Accepted for publication 29 June 2002
However, the question of whether TMJ OA may be linked to the onset, progress, or cessation of TMJ-related signs and symptoms remains a point of controversy. TMJ effusion describes the magnetic resonance (MR) imaging finding of
2002 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved.
MRI findings in patients with unilateral temporomandibular joint pain a hyperintensity signal inside the joint space1,21,24,25,30,32,35. W & B emphasized the importance of effusion in MR imaging of the TMJ, and suggested TMJ effusion to represent an inflammatory response to a dysfunctional disk-condyle relationship34. S & W compared retrodiskal tissue intensity in painful and painless TMJs, and found a significant association between TMJ pain and increased signal intensity24. However, A and coworkers, in their article based on a sample of 123 TMJs, failed to relate TMJ pain and TMJ effusion; they described TMJ effusion to be related to the MR imaging finding of internal derangement and osteoarthrosis1. Further, M and associates disclosed that the MR imaging detection of high signal intensity in the closed locking TMJ did not directly relate to the presence of TMJ pain21. These differences in outcome may be related to the diagnostic approach of TMJ-related pain applied in the respective studies. Using MR imaging as a gold standard for the diagnoses of TMJ OA, and effusion, the purpose of the present study was to assess whether in TMJ pain patients, the presence of unilateral TMJ pain may be linked to MR imaging findings of TMJ OA, and/or TMJ effusion. Material and methods The study group consisted of 112 consecutive TMJ patients, referred from medical practitioners and dentists in the community to the Orofacial Pain and TMD Clinic in the Department of Oral and Maxillofacial Surgery at the University of Innsbruck. This clinic is the primary referral centre for TMD at the Institution as both conservative and surgical treatments are offered. There were 97 females and 15 males, aged between 15 and 78 years with a mean age of 38.2 years. The subjects were informed about the study procedure and informed consent was received. Criteria for including a patient were (a) report of orofacial pain referred to the TMJ, (b) presence of unilateral TMJ pain during palpation, during function, and/or during unassisted or assisted mandibular opening, (c) absence of signs and symptoms that characterized a diagnosis of myalgia, (d) no history of trauma, and (e) absence of collagen vascular disease. To determine whether patients classified with unilateral TMJ pain may be linked to MR imaging findings of TMJ
OA and/or TMJ effusion, the subjects underwent clinical and MR imaging investigation. One clinician performed the clinical evaluation on the subject and, every time the patient underwent clinical investigation, MR imaging was performed immediately afterward. With the study being double-blind, the clinical records and images were interpreted by the clinician and medical radiologist independently without knowledge of the results of the other investigator. The MR images were obtained and interpreted prospectively by an experienced radiologist. The clinical assessment consisted of a standardized evaluation of signs and symptoms of TMD, including mandibular range of motion, joint sounds, joint and muscle pain on palpation, and pain on unassisted or assisted mandibular opening37. Mandibular range of motion was evaluated for maximum opening and lateral movements. Maximum opening was measured from central maxillary incisor to the opposing mandibular incisor on a millimetre ruler. Lateral movements were measured relative to the maxillary midline with the teeth slightly separated. The TMJs were auscultated with a stethoscope, with the subject performing three openings, and three lateral and protrusive movements. These were described as single and reciprocal clicks. TMJ pain on palpation was assessed through bilateral manual palpation of the lateral aspect of the condyle. The parameter of TMJ pain during unassisted mandibular opening was assessed by asking the patient to perform maximum voluntary jaw opening. Assisted opening was performed by the application of force to the lower and upper incisors with the middle finger and thumb. A positive pain score was recorded by the examiner if a patient experienced a distinctively painful sensation in the TMJ during the procedure. Pain of the muscles was assessed as positive or negative by a bilateral manual palpation technique. The following sites were palpated: the anterior, posterior, and middle temporalis, the tendon of temporalis, the superficial and deep masseters, the lateral pterygoid, and the anterior and posterior digasric muscle. A diagnosis of myalgia was assigned if palpation produced a clear reaction from the patient, i.e., if the patient experienced a distinctly tender or painful sensation in two or more muscle sites with muscle palpation pain of two or more on a 0 to 3 severity scale34.
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MR imaging was carried out with a 1.5 T MR scanner (Vision, Siemens AG, Erlangen, Germany) and a dedicated circular-polarized transmit-and-receive TMJ coil. The data were collected on a 252256 matrix with a field of view of 145 mm giving a pixel size of 0.600.57 mm. With the patient in a supine position, 15 paracoronal and 8 para-sagittal slices were obtained of each TMJ using a TSE (turbo spin echo)-PD (proton density) sequence (repitition time of 2800 ms, echo time of 15 ms) and a TIRM (turbo inversion recovery magnitude) sequence (repitition time of 4000 ms, echo time of 30 ms, inversion time of 150 ms) with thin slices of 3 mm. MR images were corrected to the horizontal angulation of the long axis of the condyle. Each subject received an individual nonferromagnetic intermaxillary device to obtain the different mouth opening positions. Sequential bilateral T1- and T2-weighted images were made at the closed mouth and the respective maximum mouth opening positions. The T1-weighted images were assesed by the radiologist using established criteria for normal versus osteoarthrotic morphology. OA was defined by the presence of flattening, subchondral sclerosis, surface irregularities, and erosion of the condyle or presence of condylar deformities associated with flattening, subchondral sclerosis, surface irregularities, erosion and osteophyte6,7. On the T2-weighted images, joint effusion was identified as an area of high signal intensity in the region of the joint space (Fig. 1). When more than a line of high signal was evident in at least two consecutive sections, it was considered positive for TMJ effusion35. The TMJ-related MR imaging findings of OA, and effusion were statistically assessed by chi-square analysis. Statistical significance of the diagnostic percent agreement between the clinical findings and MR imaging diagnoses was evaluated using the Kappa statistical test. Significance was set at P<0.05. For all statistical analysis the SPSS package (SPSS Inc., 1997) was used. Results An MR imaging diagnosis of TMJ OA was established in 173 of 224 TMJs (77.2%), while 51 TMJs were found to have an absence of OA (22.8%). In TMJs with pain, 99 of the 112 joints (88.4%) were characterized by the presence of an OA, while in the TMJs without pain, 74 of the 112 joints (66.1%)
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Emshoff et al. agreement between the clinical and the MR imaging findings (Table 3).
Discussion
Fig. 1. Sagittal closed mouth-related MR image shows left TMJ with presence of effusion (arrows), and presence of osteoarthrosis of the condyle, which is flattened and deformed (short arrow).
Table 1. Relationship between MRI diagnosis and TMJ pain (n=224) TMJs Pain side (%) (n=112)
Non-pain side (%) (n=112)
Sum (%) (n=224)
Osteoarthrosis Absence of osteoarthrosis Presence of osteoarthrosis
13 (11.6) 99 (88.4)
38 (33.9) 74 (66.1)
51 (22.8) 173 (77.2)
Effusion Absence of effusion Presence of effusion
58 (51.8) 54 (48.2)
90 (80.4) 22 (19.6)
148 (66.1) 76 (33.9)
MRI diagnosis
MRI, magnetic resonance imaging; TMJ, temporomandibular joint; (%), percent; n, number of TMJs.
showed an abnormal morphology. Analysis of side-related data showed a significant relationship between the clinical finding of TMJ pain and the MR imaging diagnoses of TMJ OA (2 =15.868, df=1, P=0.000) (Table 1). TMJ effusion was observed in 76 of 224 TMJs (33.9%). In TMJs with pain, 54 of the 112 joints (48.2%) were characterized by the presence of effusion, while in the TMJs without pain, 22 of the 112 joints (19.6%) showed an abnormal relationship. There was a significant correlation between the clinical finding of TMJ pain and the MR imaging diag-
nosis of TMJ effusion (2 =20.393, df=1, P=0.000) (Table 1). MR imaging showed effusion in 5 (9.8%) of the TMJs with an absence of OA, and 71 (41.0%) of the TMJs with OA. There was a significant relationship between the MR imaging finding of TMJ effusion and those of TMJ OA (2 =17.144, df=1, P=0.000) (Table 2). Comparing the agreement between the presence of TMJ pain and the MR imaging diagnoses of OA and effusion, the TMJ group K-values for OA, effusion, and ‘OA and effusion’ rated 0.22, 0.29, and 0.30 respectively, indicating poor
This study confirms MR imaging to be a valuable diagnostic method for measuring local TMJ-related signs of OA3,10,16,27,33. Regarding the prevalence of TMJ OA (77.2%), the findings correspond to the reports of other authors who described frequencies of imaging signs of TMJ OA in TMD patients as ranging from 11.4% to 58%3,10,17,18,36. The finding of a significant relationship between structural TMJ OA changes and TMJ-related findings of pain may contrast the results of several authors reporting high prevalences of radiographic signs of OA in asymptomatic TMJs ranging from 50% to 90%4,11,36. However, the fact that prevalences of TMJ OA are reported with great variations in the literature, and that multiple-factor studies using specific clinical and imaging criteria for diagnosing TMJ OA are still lacking, indicates the neccessity for further investigations to test the hypothesis that TMJ-related TMD patients with specific clinical symptoms do not differ from control subjects with regard to the presence of specific imaging signs of TMJ OA5. The results of MR imaging in the present study showed TMJ pain to be associated with a high rate of TMJ effusion (48.2%). This observation compares favourably with the results of other authors reporting prevalences of TMJ effusion in TMJs with pain ranging from 13% to 88%21,25, 30. while prevalence rates in TMJs without pain have been described as ranging from 0% to 38.5%30,35. TMJ effusion was more frequently observed in TMJ OA (41.0%) than in TMJs without OA (9.8%). Further, there was a significant relationship between the finding of TMJ effusion and those of TMJ OA. These results may be regarded as comparable with those of a previous study describing a significant association between MR imaging diagnoses of TMJ OA and effusion; it showed OA to occur primarily in TMJs with effusion, the reported prevalences ranging from 13% for absence of OA to 38% for OA1. The findings of a significant relationship between the presence of TMJ pain and the MR imaging diagnoses of TMJ effusion are in agreement with those of some authors suggesting TMJ effusion to represent an inflammatory response
MRI findings in patients with unilateral temporomandibular joint pain Table 2. Relationship between MRI diagnosis of TMJ effusion and TMJ osteoarthrosis (n=224) TMJs MRI diagnosis Absence of osteoarthrosis Presence of osteoarthrosis Sum
Presence of effusion (%)
Absence of effusion (%)
Sum (%)
5 (9.8) 71 (41.0) 76 (33.9)
46 (90.2) 102 (59.0) 148 (66.1)
51 (100) 173 (100) 224 (100)
MRI, magnetic resonance imaging; TMJ, temporomandibular joint; n, number of TMJs; (%), percent. Table 3. Diagnostic agreement between clinical finding of TMJ pain and MRI diagnoses of TMJ osteoarthrosis, and effusion in patients with unilateral TMJ pain (n=224)
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may show decisive differences in the areas of pathogenesis, treatment and/or prognosis. The study’s findings suggest that while clinical pain is correlated to TMJ-related MR imaging findings, clinical pain in and of itself, is not reliable for predicting the presence of TMJ OA and/or effusion. Validation of MR imaging diagnoses would involve the investigation of crosssectional and longitudinal evidence to assess decisive differences in terms of prognosis and/or treatment outcome.
MRI diagnosis TMJ pain group % Diagnostic agreement K-value*
Osteoarthrosis
Effusion
‘Osteoarthrosis and effusion’
61.2 (n=137) 0.22
64.3 (n=144) 0.29
64.7 (n=145) 0.30
TMJ, temporomandibular joint; MRI, magnetic resonance imaging; n, number of TMJs; (%), percent; *K-value: 0–0.2, no reliability; 0.2–0.4, poor reliability; 0.4–0.6, fair reliability; 0.6–0.8, good reliability; and 0.8–1.0, excellent reliability.
to a dysfunctional TMJ24,35, while others failed to correlate the MR imaging detection of effusion to the presence of TMJ pain1,21. These differences may be related to the diagnostic approach of TMD and TMJ-related pain applied in the respective studies. Using strict inclusion and exclusion criteria to define homogeneous TMJ pain groups, further studies including a large sample size of TMD patients and non-TMD subjects may be warranted to describe TMJ pain specific data on TMJ side-related prevalences of ID, and effusion. The study revealed an unacceptable level of agreement between the clinician in his finding of TMJ pain and the radiologist in his corresponding MR imaging diagnoses of OA, effusion, and ‘OA and effusion’. Several authors investigated the reliability of clinical items for TMJ OA using arthrography and MR imaging as a ‘gold standard’. The clinical predictions of OA were validated by arthrography and MR imaging in 35% and 67%, respectively10,17,22. With the additional use of tomographic films prior to arthrography the diagnostic agreement even was described with 95% and 100%2. This would seem to support the concept, that beside clinical joint crepitus and/or grating, the diagnosis of osteoarthrosis is primarily a radiographic diagnosis5. Several studies have focused on the importance of degenerative changes as the underlying mechanism in the aetiology of TMJ-related pain and dysfunction12,13–27. Arthroscopic studies have confirmed the concept that inflammatory processes of the synovium, cap-
sule, or retrodiscal tissues are the underlying mechanisms for the occurrence of TMJ-related pain38, while divergent correlations were found between local arthroscopic and light microscopic signs of inflammation. Factors like direct mechanical injury, hypoxiaperfusion, and neurogenic inflammation were regarded as aetiologic in the production of synovitis, cartilage degeneration, and osteoarthritis19,20. The introduction of TMJ synovial fluid analysis has enhanced the knowledge of the underlying biochemical events that contribute to the pathologic conditions of the TMJ. Biochemical investigations of the TMJ synovial fluid in combination with arthroscopic evaluation of the morphologic appearance of the cartilage and synovium have suggested a significant relationship between osteoarthritis and synovitis14,15,38, and an important role of cytokines in TMJ pain and dysfunction by taking part in the mediation of acute and chronic inflammation and associated connective tissue destruction9,23,26,31. The findings raise the question of whether the use of clinical TMJ-related diagnoses may need to be supplemented by MR imaging to distinguish among subtypes of TMJ disorders. From a methodological point of view, aetiology, prognostic statements, and implications for treatment are considered to be the main indicators for the utility of diagnostic classifications29. Further research may be warranted to assess the diagnostic validity of MR imaging-related variables of TMJ OA, and effusion by determining how well these diagnoses
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Address: Dr Ru¨diger Emshoff Ho¨henstraße 5 A-6020 Innsbruck Austria Tel.: 0043/512/276661 Tel.: 0043/512/504/4373 Fax: 0043/512/504/4371 E-mail: Ruediger–Emshoff@hotmail.com