Clinical versus magnetic resonance imaging findings with internal derangement of the temporomandibular joint: An evaluation of anterior disc displacement without reduction

J Oral Maxillofac Surg 60:36-41, 2002

Clinical Versus Magnetic Resonance Imaging Findings With Internal Derangement of the Temporomandibular Joint: An Evaluation of Anterior Disc Displacement Without Reduction Ru ¨ diger Emshoff, MD, DMD,* Katharina Innerhofer, MD,† Ansgar Rudisch, MD,‡ and Stefan Bertram, MD, DMD§ Purpose:

The purpose of this study was to investigate whether the clinical finding of anterior disc displacement without reduction (ADWOR) and pain in the temporomandibular joint (TMJ) is correlated to the magnetic resonance imaging (MRI) findings of TMJ internal derangement (ID). Patients and methods: The TMJ group was composed of 55 TMJ pain patients who were assigned a clinical diagnosis of unilateral ADWOR. The control group consisted of 58 nonpainful TMJ patients. Sagittal and coronal MR images were obtained to establish the incidence and type of ID. Results: Using chi-square analysis, the results showed a significant relationship between the presence of pain and the MRI diagnosis of ID (P ⫽ .000) and its type (P ⫽ .000). Use of the kappa statistical test indicated poor diagnostic agreement between the presence of pain and the MRI diagnosis of ID (␬ ⫽ 0.37) and disc displacement with reduction (␬ ⫽ 0.20). The diagnostic agreement for disc displacement without reduction was 78.8%, with a corresponding ␬-value of 0.58, indicating fair agreement between the clinical and the MRI diagnosis. Conclusion: The results suggest that TMJ pain associated with ADWOR is correlated with MRI diagnoses of ID and the ID type. These data confirm the use of the clinical diagnostic criteria for disc displacement without reduction as a reliable method of predicting similar MRI diagnoses. © 2002 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 60:36-41, 2002 For a better definition of diagnostic subgroups of patients with orofacial pain and temporomandibular disorders (TMD), data supporting decisive differences in the areas of pathogenesis, treatment, and/or prognosis are essential.1 In several articles in the literature, the classification, diagnosis, and treatment of temporomandibular joint (TMJ)-related disorders are

based on an appropriate diagnosis of the position and shape of the TMJ disc.2-5 However, in terms of clinical decision-making there are only a few studies available concerned with the question of whether the disccondyle relationship is a significant factor in the onset of TMJ-related pain and dysfunction.6,7 Using magnetic resonance imaging (MRI) as a gold standard for the diagnosis of TMJ disc-condyle relationship, the purpose of the present study was to assess whether the clinical finding of anterior disc displacement without reduction (ADWOR) and pain in the TMJ is related to the MRI findings of TMJ internal derangement (ID).

Received from the University of Innsbruck, Innsbruck, Austria. *Associate Professor, Department of Oral and Maxillo-Facial Surgery. †Research Fellow, Department of Oral and Maxillo-Facial Surgery. ‡Consultant, Departments of Magnetic Resonance Imaging and Radiology. §Consultant, Department of Oral and Maxillo-Facial Surgery. Address correspondence and reprint requests to Dr Emshoff: Ho ¨ henstraBe 5, A - 6020 Innsbruck, Austria; e-mail: [email protected]

Patients and Methods SUBJECTS

The study group consisted of 55 TMJ pain patients and 58 nonpainful 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 center

© 2002 American Association of Oral and Maxillofacial Surgeons

0278-2391/02/6001-0007$35.00/0 doi:10.1053/joms.2002.29071

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EMSHOFF ET AL

for TMD at the institution because both conservative and surgical treatments are offered. Patients who were referred to the center for treatment reported pain and/or dysfunction of the temporomandibular region as the primary problem. The TMJ pain group consisted of 46 females and 9 males, with a mean age of 35.3 years (range, 14 to 79 years), and the nonpainful TMJ group consisted of 51 females and 7 males, with a mean age of 32.6 years (range, 16 to 75 years). The subjects were informed about the study procedure, and informed consent was received. Criteria for including a TMJ pain patient were the presence of a unilateral anterior disc displacement without reduction (ADWOR), a report of orofacial pain referred to the TMJ, as well as the presence of TMJ pain during palpation, function, and/or unassisted or assisted mandibular opening. Criteria for including a nonpainful TMJ patient were the absence of a TMJ with a diagnosis of disc displacement with or without reduction and the absence of a TMJ with pain during palpation, function, and unassisted or assisted mandibular opening. Application of the criteria resulted in a study group of 55 painful ADWOR TMJs and 58 nonpainful TMJs. A clinical diagnosis of TMJ ID was made according to the Clinical Diagnostic Criteria for Temporomandibular Disorders (CDC/TMD).8 Criteria for each diagnostic subgroup were specified as guidelines to be used in the clinical diagnostic process. Clinical evidence of the absence of an ID was based on the lack of inclusion criteria defining one of the internal derangement subgroups. Patients assigned a TMD diagnosis of myalgia, degenerative joint disease, or collagen vascular disease, and patients with a history of trauma, were not included in the study. To determine the reliability of a clinical diagnosis of TMJ pain associated with ADWOR predicting an MRI diagnosis of ID, the subjects underwent clinical and MRI investigation. One clinician performed the clinical evaluation on the subject and, every time the patient underwent clinical investigation, MRI was performed immediately afterward. With the study being double-blind, the clinical records and images were interpreted by the clinician and radiologist independently without knowledge of the results of the other investigator. The clinical assessment consisted of a standardized evaluation of mandibular range of motion, joint pain, and auscultation of joint sounds. Mandibular range of motion was evaluated by maximum opening and lateral movements. Maximum opening was measured from the maxillary central incisor to the opposing mandibular incisor using a millimeter ruler. Lateral movements were measured relative to the maxillary midline with the teeth slightly separated. TMJ pain was identified during palpation, mandibular range of

motion, or assisted mandibular opening. The TMJs were auscultated with a stethoscope, with the subject performing 3 mouth openings and 3 lateral and protrusive movements. Sounds were described as single and reciprocal clicks.9 MAGNETIC RESONANCE IMAGING

MRI was carried out with a 1.5T MR scanner (Vision, Siemens AG, Erlangen, Germany) and a dedicated circular-polarized transmit-and-receive TMJ coil. The data were collected on a 252 ⫻ 256 matrix with a field of view of 145 mm, giving a pixel size of 0.60 ⫻ 0.57 mm. With the patient in a supine position, 15 coronal slices and 8 parasagittal slices were obtained of each TMJ using a TSE-PD sequence (repetition time [TR], 2,800 ms; echo time [TE]; 15 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 images were made at the closed mouth and the respective maximum mouth opening positions. Those images selected for analysis of the disc-condyle relationship depicted the disc, condyle, articular eminence, and glenoid fossa. Normal disc position was defined by location of the posterior band of the disc at the superior, or 12 o’clock, position relative to the condyle, whereas disc displacement was defined as the posterior band of the disc being in an anterior, anteromedial, anterolateral, medial, or lateral position relative to the superior part of the condyle. The disc-condyle relationship was categorized as normal (absence of internal derangement) or as disc displacement with or without reduction, based on the closed mouth-disc position and the relationship in the open mouth-position.7 DATA ANALYSIS

The chi-squared analysis was done to test for the relationship between TMJ pain associated with ADWOR and the MRI findings of TMJ ID and ID type. Statistical significance of the diagnostic percent agreement between the clinical findings and MRI diagnoses was evaluated using the kappa statistical test. Significance was set at P ⬍ .05. The SPSS ⫻ package (SPSS Inc, Chicago, IL) was used for all statistical analyses.

Results The results showed that in TMJs with a clinical diagnosis of ADWOR and pain, in 5 of the 55 patients, the closed mouth views (9.1%) had a normal disccondyle relationship, while in 50 (90.9%) it showed an abnormal relationship. A total of 45.5% of the

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ANTERIOR DISC DISPLACEMENT WITHOUT REDUCTION

Table 1. MRI DIAGNOSIS OF TYPE OF CLOSED MOUTH-RELATED DISC-CONDYLE RELATIONSHIP IN TMJs WITH ADWOR AND PAIN AND IN NONPAINFUL TMJs ADWOR ⫹ Pain TMJs (n ⫽ 55)

ADWOR ⫹ Pain/Nonpain TMJs (n ⫽ 113)

Nonpainful TMJs (n ⫽ 58)

MRI Diagnosis

P (%)

LCDD (%)

MCDD (%)

P (%)

LCDD (%)

MCDD (%)

P (%)

LCDD (%)

MCDD (%)

Absence of DD Anterior DD Anterolateral DD Anteromedial DD Lateral DD Medial DD Total LCDD/MCDD

5 (9.1) 25 (45.5) 16 (29.1) 8 (14.6) — 1 (1.8) 55 (100) —

— — 16 (29.1) — — — 16 (29.1)

— — — 8 (14.6) — 1 (1.8) 9 (16.4)

27 (46.6) 9 (15.5) 8 (13.8) 11 (19.0) — 3 (5.1) 58 (100) —

— — 8 (13.8) — — — 8 (13.8)

— — — 11 (19.0) — 3 (5.1) 14 (24.1)

32 (28.3) 34 (30.1) 24 (21.2) 19 (16.8) — 4 (3.5) 113 (100) —

— — 24 (21.2) — — — 24 (21.2)

— — — 19 (16.8) — 4 (3.5) 23 (20.4) 1.0 —

1.8

0.6

Abbreviations: MRI, magnetic resonance imaging; ADWOR, anterior disc displacement without reduction; TMJ, temporomandibular joint; P, prevalence; LCDD, lateral component of disc displacement; MCDD, medial component of disk displacement; DD, disc displacement; LCDD/MCDD, ratio between sideways and rotational locations, declining laterally or medially.

closed mouth positions were characterized by anterior disc displacement, while 29.1% had anterolateral disc displacement, 14.6% had anteromedial disc displacement, and 1.8% had medial disc displacement. The ratio between sideways and rotational locations was 1.8 (Table 1). In nonpainful TMJs the MRI revealed the highest incidence of ID to be anteromedial disc displacement (19.0%), whereas the incidence of anterior disc displacement and anterolateral disc displacement were 15.5% and 13.8%, respectively. Medial disc displacement showed an incidence of 5.1%. The ratio between sideways and rotational locations, either laterally or medially, was 0.6 (Table 1). The highest frequency of ID type in the group with ID was disc displacement without reduction (84%), while in TMJs without pain the highest incidence of ID type was disc displacement with reduction (64.5%) (Table 2). Using chi-squared analysis, the results showed a significant relationship between the clinical diagnosis

of TMJ ADWOR and pain and the MRI diagnoses of TMJ ID (P ⫽ .000) and TMJ ID type (P ⫽ .000) (Tables 3, and 4). Comparing the agreement between the clinical and the MRI diagnoses of ID, the TMJ pain associated with ADWOR group ␬-values for ID, disc displacement with reduction, and disc displacement without reduction were 0.37, 0.20, and 0.58, respectively, indicating poor reliability between the clinical and MRI diagnoses of ID and disc displacement with reduction, and fair reliability for disc displacement without reduction (Table 5).

Discussion With ADWOR and pain in the TMJ, the closed mouth-related incidence of anterior disc displacement and anterolateral disc displacement was found to be higher than that for anteromedial disc displacement, medial disc displacement, and lateral

Table 2. MRI DIAGNOSIS OF TYPE OF ID IN TMJs WITH ADWOR AND PAIN AND IN NONPAINFUL TMJs

MRI Diagnosis Absence of ID Presence of ID Disc displacement with reduction Anterior Anterolateral Anteromedial Lateral Medial Disc displacement without reduction Anterior Anterolateral Anteromedial Lateral Medial

ADWOR ⫹ Pain TMJs (%)

Nonpainful TMJs (%)

Total (%)

5 (9.1) 50 (90.9) 8 (16.0) 5 (62.5) 1 (12.5) 2 (25.0) — — 42 (84.0) 20 (47.6) 15 (35.7) 6 (14.3) — 1 (2.4)

27 (46.6) 31 (53.5) 20 (64.5) 6 (30.0) 8 (40.0) 5 (25.0) — 1 (5.0) 11 (35.5) 3 (27.3) — 6 (54.6) — 2 (18.2)

32 (28.3) 81 (71.7) 28 (34.6) 11 (39.3) 9 (32.1) 7 (25.0) — 1 (3.6) 53 (65.4) 23 (43.4) 15 (28.3) 12 (22.6) — 3 (5.7)

Abbreviations: MRI, magnetic resonance imaging; ADWOR, anterior disc displacement without reduction; TMJ, temporomandibular joint; ID, internal derangement.

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EMSHOFF ET AL

Table 3. RELATIONSHIP BETWEEN CLINICAL AND MRI DIAGNOSES OF ID IN TMJs WITH ADWOR AND PAIN AND IN NONPAINFUL TMJs

MRI Diagnosis

ADWOR ⫹ Pain TMJs (%)

Nonpainful TMJs (%)

Total (%)

Absence of ID Presence of ID Total

5 (9.1) 50 (90.9) 55 (100)

27 (46.6) 31 (53.4) 58 (100)

32 (28.3) 81 (71.7) 113 (100)

NOTE. ␹2 ⫽ 19.516; P ⫽ .000; df ⫽ 1. Abbreviations: MRI, magnetic resonance imaging; ID, internal derangement; ADWOR, anterior disc displacement without reduction; TMJ, temporomandibular joint.

disc displacement, while in nonpainful TMJs anterior disc displacement and anteromedial disc displacement were more frequent than anterolateral disc displacement, medial disc displacement, and lateral disc displacement. These findings correspond to the reports of some authors who described either anterior disc displacement and anterolateral disc displacement6,7, or anterior disc displacement and anteromedial disc displacement10 to be the most frequently encountered, but differs from those reporting the occurrence of anterior disc displacement and medial rotary disc displacement11 to be most prevalent. The results of the current investigation are consistent with those of some authors who reported either a lateral7 or medial10-13 component of disc displacement to be more prevalent, but is inconsistent with those who showed the frequency of the medial and lateral displacement to be relatively equal.6 However, such data may be not directly comparable, because these studies failed to use TMD-specific subgroups, reporting the prevalence of closed mouth-related disc-condyle relationships in subjects classified as symptomatic TMD patients and asymptomatic volunteers. In view of the fact that efforts in making a differential diagnosis are only useful in instances when there are decisive differences in at least prognosis and/or treatment, ongoing studies would be in order to evaluate whether specific criteria for MRI-related diagnoses may predict differ-

ences in specific treatment-related outcome measures.14-17 The results of MRI in the present study showed both TMJs with ADWOR and pain (90.9%) and nonpainful TMJs (53.5%) to be associated with a high rate of IDs. This observation is consistent with those of other studies,6,7 which showed occurrence rates of ID in TMD patients ranging from 77% to 89%, while the incidence in asymptomatic volunteers ranged from 30% to 33%.6,7 The high incidence rates in TMD patients supports the concept of ID being significantly involved in the production of TMD pain and dysfunction. However, given the fact that ID alone is not always associated with pain and dysfunction, more data may be necessary if ID is to become generally accepted as a diagnostic guide in the management of TMJ patients, especially in cases where surgery is under consideration. Ongoing studies involving a large number of TMD and non-TMD subjects are needed to show any TMD-specific effect of ID and ID type. This study revealed a significant relationship between the clinical presence of TMJ pain associated with ADWOR and the MRI diagnosis of ID and ID type. These results may be regarded as comparable with those of previous studies reporting that in the more specified TMD subgroup of “closed lock” or “anterior disc displacement without reduction” the affected TMJ may be associated with a high incidence of MRI-related disc displacement without reduction, ranging from 47.5% to 100%.19,36-40 However, there are no studies available in the literature describing CDC/TMD-specific data on TMD subject and/or the TMJ side-related incidence rate of disc displacement, ID, and/or the type of disc displacement and/or ID. This study used a common set of specified operational criteria for classifying TMD patients. This approach to clinical assessment produced an unacceptable level of agreement between the clinical finding of TMJ ADWOR and pain and the radiologist’s corresponding MRI diagnosis of ID, disc displacement with reduction, and disc displacement without reduction. Several authors have investigated the reliability of the

Table 4. RELATIONSHIP BETWEEN CLINICAL DIAGNOSIS OF ID AND MRI DIAGNOSIS OF ID IN TMJs WITH ADWOR AND PAIN AND IN NONPAINFUL TMJs

MRI Diagnosis

ADWOR ⫹ Pain TMJs (%)

Nonpainful TMJs (%)

Total (%)

Absence of ID Disc displacement with reduction Disc displacement without reduction Total

5 (9.1) 8 (14.5) 42 (76.4) 55 (100)

27 (46.6) 20 (34.5) 11 (19.0) 58 (100)

32 (28.3) 28 (24.8) 53 (46.9) 113 (100)

NOTE. ␹2 ⫽ 38.347; P ⫽ .000; df ⫽ 2. Abbreviations: ID, internal derangement; MRI, magnetic resonance imaging; ADWOR, anterior disc displacement without reduction; TMJ, temporomandibular joint.

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ANTERIOR DISC DISPLACEMENT WITHOUT REDUCTION

Table 5. DIAGNOSTIC AGREEMENT BETWEEN CLINICAL AND MRI DIAGNOSIS

MRI Diagnosis TMJ ADWOR ⫹ Pain Group

Internal Derangement

Disc Displacement With Reduction

Disc Displacement Without Reduction

Percentage of Diagnostic Agreement ␬-Value*

68.1 (n ⫽77) 0.37

40.7 (n ⫽46) 0.20

78.8 (n ⫽89) 0.58

Abbreviations: MRI, magnetic resonance imaging; TMJ, temporomandibular joint; ADWOR, anterior disc displacement without reduction. *␬-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.

clinical diagnosis of ID using arthrography and MRI as a “gold standard.” The reported percent agreement ranged from 59% to 90%, depending on the diagnostic criteria used in the studies.22,23,25-31 The ambiguity between the essential and nonessential features of the various TMD subgroups may have resulted in low reliabilities concerning the classification of patient groups in these studies. With regard to the diagnostic system applied in the present study, the overall intra and interobserver reliability has not been tested yet. However, the use of strict inclusion and exclusion criteria may have defined homogeneous clinical subgroups of TMD patients. Further studies, including a larger sample size of TMD and non-TMD subjects, are warranted to provide CDC/TMD-specific data on TMD subject-related and/or the TMJ side-related incidence of ID and ID type. With the rapid progress made in TMJ imaging techniques, many studies have focused on the importance of ID as an underlying mechanisms in the etiology of TMJ-related pain and dysfunction. The biologic concept of disc displacement has been emphasized by several authors,6,7 and the conditions have been regarded as requiring surgical correction where conservative treatment has failed to improve the signs and symptoms.32,33 However, the question of whether TMJ disc displacement is the result, the cause, or an accompanying factor remains a point of controversy4,34,35 With the introduction of TMJ arthroscopy and synovial fluid analysis, the “synovitis and osteoarthritis” concept was developed, emphasizing these conditions as the underlying mechanisms in the pathogenesis of TMJ-related pain and dysfunction.36-41 Factors, such as direct mechanical injury, hypoxiaperfusion, and neurogenic inflammation, have been regarded as etiologic in the production of synovitis, cartilage degeneration, and osteoarthritis.42,43 To identify which parameters may define TMJ pain patients or normals, multiple-factor studies, including additional morphologic variables may be necessary, while from a methodologic point of view only a wellcontrolled incidence study rather than a case-controlled study can clarify the etiologic contribution of TMJ ID to TMJ pain.44 The results of this study suggest that the TMJ-related condition of pain associated with ADWOR is

correlated with the MRI diagnosis of ID and the ID type. These data confirm the use of the clinical diagnostic criteria of disc displacement without reduction as a reliable instrument in predicting the MRI diagnosis of this condition.

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