Hard and soft tissue imaging of the temporomandibular joint 30 years after diagnosis of osteoarthrosis and internal derangement

J Oral Maxillofac Surg 54:1270-1260, 1996

Hard and Soft Tissue Imaging of the Temporomandibular Joint 30 Years After Diagnosis of Osteoarthrosis and In ternal Derangement RENY DE LEEUW, DDS, PHD,* GEERT BOERING, DDS, PHDt BART VAN DER KUIJL, DDS, PHD,* AND BOUDEWIJN STEGENGA, DDS, PHD§ Purpose: This article describes the clinical and imaging findings in the temporomandibular joints (TMJs) of patients 30 years after the initial diagnosis of osteoarthrosis and internal derangement. Patients and I\llethocfs: Fifty-five TMJs with a history of osteoarthrosis and internal derangement and 37 contralateral TMJs that were asymptomatic 30 years ago were examined in 46 former patients. To visualize degenerative changes of the bony parts of the TMJ, transpharyngeal and transcranial radiographs were made; to visualize disc position, sagittal Tl-weighted magnetic resonance (MR) images were made. For comparison, 22 TMJs of an agematched control group without complaints related to the masticatory system were similarly examined. Results: Thirty years after the initial diagnosis of osteoat-throsis and internal derangement, clinical signs in former patients hardly differed from those of control subjects. Radiographic signs were significantly more common and more severe in former patients. A high percentage of osteoarthrosis and internal derangement was seen on MRI in both TMJs with a history of osteoarthrosis and internal derangement and in the contralateral TMJs. It appeared that osteoarthrosis and internal derangement in the contralateral TMJs had developed asymptomatically in most cases. None of the patients had required treatment for the contralateral TMJ; only one fourth of the patients had noticed symptoms. In the control subjects, osteoarthrosis and internal derangement were infrequently seen. A significant correlation was found between disc position and the severity of radiographically detectable degenerative changes of the TMJ. Conc/usions: It was concluded that 30 years after initial diagnosis there were few clinical signs of osteoarthrosis and internal derangement, although radiographic signs were extensive. Bilateral osteoarthrosis and internal derangement, with one symptomatic and one asymptomatic TMJ, is a common phenomenon. Moderate to severe radiographically detectable degenerative changes may be the only sign of an underlying internal derangement.

Received from the Department of Oral and Maxillofacial University Hospital, Groningen, The Netherlands. * Research fellow, TMJ Research Group. 7 Professor. $ Research associate, TMJ Research Group. 5 Research associate, TMJ Research Group.

Address correspondence and reprint requests to Dr de Leeuw: University of Kentucky, College of Dentistry, Orofacial Pain Center Room D314, 800 Rose St, Lexington, KY 40536-0084.

Surgery,

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A combination of osteoarthrosis and internal derangement is among the most common disorders of the temporomandibular joint (TMJ). This condition is clinically characterized by clicking, locking, pain, restriction of movement, and crepitus.’ In the early 60s three main stages of the disorder were distinguished based on the clinical and radiographic findings. These were later substantiated by follow-up studies in the early 1970s and 1980~.~~~ It has been suggested that the disorder runs a natural course ending in a state in which there are few clinical signs and symptoms, but there may be considerable, radiographically detectable degenerative changes. l-3 It is now generally accepted that the stages of the disorder are closely related to different positions of the articular disc relative to the condyle. Indeed, several cross-sectional studies have suggested that TMJ clicking, indicative of a reducing disc displacement, progresses into locking, indicative of a permanent disc displacement4-7 Clinical followup studies of 1 and 3 years, however, have reported persistent reciprocal clicking in 65% and 71% of the cases studied.8’9 Apparently, within the time limits of these studies, the initial stage was not progressive in most patients. Several studies have shown that in TMJs with normal superior disc position, or in TMJs with reciprocal clicking, no or hardly any morphologic or structural bony changes are observed on conventional radiographs.10-12 Conversely, it has been shown that in TMJs with a permanent disc displacement, radiographically detectable degenerative changes become evident within a few months after the disc has become permanently displaced.i”,’ ‘,I3 Limited information is available on the longitudinal course of osteoarthrosis and internal derangement, especially with regard to the radiographic status of TMJs in which reciprocal clicking persists. Therefore, the aim of this study was to evaluate the current clinical and radiographic status of TMJs with a 30-year history of osteoarthrosis and internal derangement and to study the relationship between radiographically detectable degenerative changes and disc position in these TMJs. Patients

and Methods

This study was part of a larger retrospective study in which the overall condition of TMJs with a 30year history of osteoarthrosis and internal derangement were evaluated by means of a structured interview, a clinical examination, and a radiographic evaluation.‘b’7 The original study consisted of 99 former patients with a history of TMJ osteoarthrosis and internal derangement and 35 control subjects who reported being free from past and present signs and symptoms in the masticatory system. The former patients were selected from 400 consecutive patients with temporomandibular pain

and dysfunction, referred to the Department of Oral and Maxillofacial Surgery of the University Hospital in Groningen, the Netherlands, 30 years ago. The former patients had received nonsurgical treatment, which at that time included reassurance, diet advice, exercise therapy, application of superficial heat, and pain medication.’ Addresses of patients who were between 50 and 70 years of age at the time of the current study were traced. The reason patients younger than 50 years old were excluded was that 30 years ago they most likely suffered from juvenile arthritis.’ The course of this disorder might not be similar to that of osteoarthrosis and internal derangement and might therefore influence the results. A pilot study concerning the current project showed that patients older than 70 might confront us with inaccurate information because of poor mental status and with noncompliance because of poor physical conditions.‘4 As a result of the age limits, 176 patients were excluded. Forty patients could not be traced, 8 had moved abroad, and 12 had died. Inclusion criteria based on the current knowledge of TMJ disorders were applied to the remaining 164 30year-old records in an attempt to diagnose in retrospect patients with either reducing or permanent disc displacement (Table l).‘* The records were evaluated separately by two examiners. If the patient suffered from temporomandibular disorders other than osteoarthrosis or internal derangement, or if full agreement between the two observers could not be reached, the case was excluded. Forty-six patients did not meet the criteria. Of the 118 patients available for recall, 19 refused to participate. The control subjects were matched to the former patients with regard to age, sex, and dentition. The control subjects were recruited from the College of Dentistry of the University Hospital, Groningen, where they had received dental care in the past 5 years. The population described in the current study consisted of those subjects who volunteered to participate in the magnetic resonance imaging (MRI) examination. Forty-six former TMJ patients, nine men and 37 women (current mean age, 59.0 + 5.3 years; range, 50 to 69 years), who had unilateral (n = 37) or bilateral (n = 9) osteoarthrosis and internal derangement of the TMJ 30 years ago, and 11 control subjects, three men and eight women (mean age, 61.1 t 6.1 years; range, 53 to 69 years) volunteered. Informed consent was obtained from all subjects. The subjects were examined clinically with regard to signs of osteoarthrosis and internal derangement. Transpharyngeal and transcranial radiographs were made to evaluate them for degenerative bony changes, and sagittal Tl-weighted MR images were made to evaluate the position of the articular disc. Three groups were distinguished: group I consisted of the 55 TMJs that were diagnosed, in retrospect, as having osteoarthrosis and internal derange-

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Inclusion Table 1. Diagnostic Were Required to be Present From, the Patients Records Reducing

Disc Displacement*

All of the following criteria?: History of clicking Reproducible clicking on opening during condylar translation Reproducible clicking on protrusion No or only slight morphologic or structural alterations in the condyle or the articular eminence on transpharyngeal or transcranial radiographs The presence of at least one of the following criteria: Reproducible clicking on lateral movements toward the contralateral side Restricted lateral movement toward the contralateral side Reproducible clicking on closing just before reaching maximal intercuspation Mandibular shift or deviation toward the affected side before the moment of clicking on opening, returning to the midline after the clicking has occurred

Criteria That in, or Deducible

Permanent

Disc Displacement

All of the following criteria?: History of clicking History of sudden onset of restricted mouth opening with cessation of the clicking Deviation of the mandible toward the affected side on opening Restricted protrusion with deviation of the mandible toward the affected side on opening Restricted lateral movement toward the contralateral side Restricted condylar translation, assessed on transphatyngeal radiographs made at maximal voluntary mouth opening Morphologic or structural alterations in the condyle or the articular eminence might be present on transpharyngeal or transcranial radiographs

* Cases with a semipermanent disc displacement, experiencing transient periods of restricted mouth opening, were also included in this stage. t The presence or absence of pain was not included as a criterion, because of the limitations of recording pain reliably or objectively.

ment 30 years ago (26 with reducing disc displacement, 29 with permanent disc displacement); group II consisted of the remaining 37 contralateral TMJs that did not have signs and symptoms of osteoarthrosis and internal derangement 30 years ago; group III consisted of the 22 TMJs of the control subjects. CLEVICAL EXAMINATION

All patients were asked whether they had requested treatment in the intervening years. In caseof unilateral complaints 30 years ago, the patients were asked whether symptoms had developed on the opposite side and, if so, whether treatment had been requested for these complaints. All subjects were examined clinically with regard to TMJ noisesand mobility character-

AND

SOFT

TISSUE

IMAGING

OF THE

TMJ

istics. Clicking, crepitus, restricted mouth opening (less than 35 mm), impaired lateral excursion to the contralateral side (difference more than 2 mm between ipsilateral and contralateral side), and deviation of the mandible on protrusion to the ipsilateral sidewere consideredsignsof clinical importance. Clicking and crepitus were recorded per TMJ; mobility characteristics were recorded per subject. RADIOGRAPHIC

EXAMINATION

Transpharyngeal radiographs were made during maximal opening of the mouth, and transcranial radiographs were made in intercuspal position. Both projections were made bilaterally in all subjects. The transpharyngeal radiographs were scored with regard to degenerative changesof the condyle, including deviation in shape,flattening, surface irregularities, erosion, sclerosis,osteophytes, and cyst formation. Translatory capacity was judged as restricted if the condyle did not reach the top of the articular eminence at maximal mouth opening. The transcranial radiographs were scored with regard to degenerative changesof the condyle, including shortening of the condyle in a mediolatera1direction (reduction of the oval projection) relative to the opposite side, erosion, sclerosis, and flattening of the articular eminence. The overall extent of radiographically detectable degenerative changes of the condyle was judged as being absent, slightly, moderate, or severely present on both the transpharyngeal and transcranial radiographs. The intraobserver and interobserver agreement of the radiographic variables have been described previously.17 MRI EXAMINATION Sagittal Tl-weighted MR images were made with the use of a dual-surface coil (6 cm) in a Philips Gyroscan operating at 1.5 tesla using a conventional spinecho technique, a repetition time of 650 msec, an echo time of 23 msec, a field of view of 110 mm, and a scanning matrix of 256 X 256 mm. Each image consisted of 11 slices of 2.5 mm thickness. The TMJs were scannedbilaterally in the closed as well as in the open mouth position. The degree of mouth opening was fixed with a bite block, available in variable sizes. In case of a clicking TMJ, the subject was instructed to open the mouth beyond the click. The position of the articular disc relative to the condyle in open and closed mouth position was determined on the MR images. Disc position was considered normal when it was situated anterosuperior to the condyle in both the open and closed mouth views. When the

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Table 2. TMJ Noises in Joints Patients and Control Subjects

Clicking Crepitus

of Former

Group I (n = 55)

Group II (n = 37)

Group III (n = 22)

15 (27.3) 18 (32.7)

6 (16.2) 7 (18.9)

4 (18.2) 3 (13.6)

Table 4. Mobility Characteristics TMJ Patients and Control Subjects

TMJ

Chisquare

P

1.80 4.03

NS NS

NOTE. Percent frequencies are given in parentheses. TMJs of former patients with osteoarthrosis and internal ment; Group II: Contralateral (30 years ago asymptomatic) former patients; Group III: TMJs of control subjects. Abbreviation: NS, not significant.

Group I: derangeTMJs of

Mouth opening Protrusion Lateral movement to ipsilateral side* Lateral movement to the contralateral side

Former Patients (n = 46)

Control Subjects (n = 11)

P < .05

1 (2.8) 10 (22.2)

1 (9.1) 2 (18.2)

NS NS

16 (34.8) 3 (6.5)

0 (0) 0 (0)

to .0211 NS

NOTE. Percent frequencies ale given in parentheses. * Ipsilateral was defined as the affected side in group 1 (in case of bilateral osteoarthrosis and internal derangement as the most affected side), and as the right TMJ in control subjects. Abbreviation: NS, not signitkzmt.

disc was situated anterior to the condyle with the mouth closed and regained its position anterosuperior to the condyle during mouth opening, the condition was considered a reducing disc displacement. A reducing disc displacement was considered partial when the disc was not situated anterior to the condyle in the closed mouth position in all slices on which the disc and condyle were depicted. When the disc was situated anterior to the condyle in both the closed and open mouth position, the condition was considered a permanent disc displacement. After a calibration session, all MR images were scored by two observers. One of the observers scored the MR images twice with an interval of 3 months. After the independent measuring sessions,items that were not agreed on were discussed until consensus was reached. Cohen’s Kappa (K) was calculated as a measure of intraobserver and interobserver agreement for judging disc position on MRI. For evaluation of disc position, 113 MR imageswere available. The kappa value for intraobserver agreement on disc position was 0.95. The kappa values for interobserver agreement on disc position were 0.82 and 0.84; respectively. These results were in agreement

Table 3. Mean Movement Deviations (mm) of Former Control Subjects

Impaired excursion to Ipsilateral side* Contralateral side Deviation on protrusion Ipsilateral side” Contralateral side

in Former

Ranges and Standard TMJ Patients and

Former Patients (n = 46)

Control Subjects (n=ll)

P

42.2 2 6.8 7.3 t 2.7

47.6 5 6.2 7.9 2 3.2

.017 NS

8.7 + 3.0

7.7 + 5.0

NS

7.9 + 2.9

6.8 t 4.7

NS

* Ipsilateral was defined as the affected side in former patients (the most affected side in case of bilateral osteoarthrosis and internal derangement) and as the right side in control subjects. Abbreviation: NS, not significant.

with recent studies on interobserver and intraobserver variation in interpretation of MR images.‘9X20 STATISTICAL

ANALYSIS

Chi-square tests for data obtained at nominal level, and the Mann-Whitney U-test for data obtained at interval level, were used to determine differences between groups with regard to the clinical and radiographic findings. Student’s t-test was used to determine differences in mandibular movement ranges. Spearman rank correlation analyseswere performed to study relationships between radiographic and MR findings. The level of significance was preset at cx = 0.05. All analyseswere performed with SPSS/PC+. Results CLINICAL

FWDINGS

None of the patients had requested retreatment for their TMJ complaints in the past three decades. Six patients who initially had unilateral complaints reported having developed symptoms on the contralateral side. None of them had requested treatment for these symptoms. No significant differences were found with regard to clicking and crepitus between the three TMJ groups (Table 2). Forty-one former patients (90%) could reach a maximal mouth opening of 35 mm or more. The mean maximal mouth opening of former patients was significantly less than that of control subjects. No differences in the mean range of horizontal excursions were found between former patients and control subjects(Table 3). Deviation on protrusion to the ipsilateral side was found more often in patients than in the control subjects. The number of patients with impaired lateral excursion to the contralateral side (or to the ipsilateral side) did not differ from that of the control group (Table 4). Exclusion of the patients

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Table 5. Frequencies Patients and Control

of Radiographically Subjects

Transphatyngeal radiograph Condylar changes Deviation in shape Flattening Surface irregularities Erosion Sclerosis Osteophytes Restricted translation Transcranial radiograph Condylar changes Reduction of oval shape Erosion Sclerosis Articular eminence change

Detectable

AND

Degenerative

SOFT

TISSUE

Changes

in TMJs

Group III (n = 22)

Group I (II = 55)

Group II (n = 37)

37 44 32 10 46 10 14

(67.3) (80.0) (58.2) (18.2) (83.6) (18.2) (25.5)

15 12 13 8 17 1 7

(40.5) (32.4) (35.1) (21.6) (45.9) (2.7) (18.9)

2 4 4 0 5 0 3

23 5 38 20

(41.8) (9.1) (69.1) (36.4)

7 6 22 9

(18.9) (16.2) (59.5) (24.3)

4 1 6 0

IMAGING

of Former

RADIOGRAPHIC

FINDINGS

Flattening and sclerosis were predominant findings on the transpharyngeal radiographs, especially in group I (osteoarthrosis and internal derangement). All features scored on the transpharyngeal radiographs, except for erosion, were found significantly more often in group I than in groups II (contralateral asymptomatic joints) and III (controls). In addition, erosion and sclerosis were found more often in group II than in group III. Cyst formation was not found in any of the TMJs. No significant differences were found between the groups with regard to the translatory capacity of the condyle. Of the five patients in whom maximal mouth opening was less than 35 mm, the translatory capacity was restricted bilaterally in two and unilaterally in two others. Reduction of the oval configuration and sclerosis were predominant findings on the transcranial radiographs. Just as on the transpharyngeal radiographs, all features scored on the transcranial radiographs, except for erosion, were found significantly more often in group I than in groups II and III. In addition, erosion and flattening of the articular eminence were found more often in group II than in group III (Table 5). Overall, group I showed significantly more severe radiographically detectable degenerative changes than

TMJ

TMJ

Chisquare

P

(9.1) (18.2) (18.2) (0.0) (22.7) (0.0) (13.6)

22.36 33.05 11.64 5.31 28.50 8.99 1.47

.oooo .oooo .0030 NS .oooil .0112 NS

(18.2) (4.5) (27.3) (0.0)

7.31 2.22 11.33 10.99

.0259* NS .0035 .0041

NOTE. Percent frequencies are given in parentheses. Group I: TMJs of former patients with osteoarthrosis and internal II: Contralateral (30 years ago asymptomatic) TMJs of former patients; Group III: TMJs of control subjects. Abbreviation: NS, not significant. * P = .0015 (chi-square = 15.39), when TMJs with bilateral osteoarthrosis and internal derangement were excluded.

with bilateral osteoarthrosis and internal derangement from the calculations with regard to the movement ranges did not influence this outcome.

OF THE

derangement;

Group

groups II and III. The changesin group II were more severe than those of group III (Table 6). MRI

FINDINGS

In 95 cases(84%), the position of the disc could be determined on the open as well as the closed mouth Table 6. Overall Extent of Radiographically Detectable Degenerative Condylar Changes TMJs of Former TMJ Patients and Control Subjects

Transpharyngeal No Slight Moderate Severe Transcranial No Slight Moderate Severe

in

Group I (n = 55)

Group II (n = 37)

Group III (n = 22)

8 10 10 27

(14.5) (18.2) (18.2) (49.1)

17 8 5 7

(45.9) (21.6) (13.5) (18.9)

17 4 0 1

(77.3) (18.2) (0.0) (4.5)

15 6 13 22

(25.5) (10.9) (23.6) (40.0)

14 10 5 8

(37.8) (27.0) (13.5) (21.6)

17 3 1 1

(77.3) (13.6) (4.5) (4.5)

NOTE. Percent frequencies are given in parentheses. Group I: TMJs of former patients with osteoarthrosis and internal derangement; Group II: Contralateral (30 years ago asymptomatic) TMJs of former patients; Group III: TMJs of control subjects. Significant differences in extent of radiographic signs on transpharyngeal respectively transcranial radiographs between groups: Group I vs Group II P = BOO3 respectively .0282; Group I vs Group III P < .OOOO respectively < .OOOO; Group II vs Group III P = .0109 respectively .0034.

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Table 7. Disc Position Assessed on MRI in TMJs of Former TMJ Patients and Control Subjects

N RDD PDD

Group I (n = 43)

Group II (n = 30)

Group III (n = 22)

4 (9.3) 13 (30.2) 26 (60.5)

8 (26.7) 13 (43.3) 9 (30.0)

17 (77.3) 4 (18.2) 1 (4.5)

NOTE. Percent frequencies are given in parentheses. TMJs of former patients with osteoarthrosis and internal ment; Group II: Contralateral (30 years ago asymptomatic) former patients; Group III: TMJs of control subjects. Abbreviations: N, normal disc position; RDD, reducing placement; PDD, permanent disc displacement.

Group I: derangeTMJs of disc dis-

image. In 14 cases,disc position could be determined only on the open or closed mouth image; in four cases it was impossible to discern any disc material at all. Displaced discs were found in 91% of TMJ group I (n = 39), in 73% (n = 22) of TMJ group II, and in 23% (n = 5) of the TMJ group III (Table 7). Reducing disc displacement was evidenced on MRI in 50% of the TMJs that were diagnosed with reducing disc displacement 30 years ago. Partial and complete reducing disc displacements were seen in equal numbers. Clicking was found more often in TMJs with reducing disc displacement than in TMJs with normal disc position or with permanent disc displacement (P < .OOOO).Crepitus was found more in TMJs with permanent disc displacement than in TMJs with normal disc position or with reducing disc displacement (P = .0319). Crepitus was positively associatedwith the severity of radiographically detectable degenerative changes (P = .0036). TMJs with normal disc position, or with reducing disc displacement, showed no or only slight radiographically detectable degenerative changes, whereas TMJs with permanent disc displacement showed significantly more moderate to severe radiographically detectable degenerative changes (Table 8, Figs 1 to 3). A moderate but significant correlation (Spearman’s Y = 0.63, P < .OOl) was found between radiographic signs and disc position. Although all control subjects had stated that they were free of TMJ signs and symptoms, reciprocal clicking was found in three of them (four TMJs). This clicking was positively associatedwith slight degenerative changes on the radiographs and with reducing disc displacement evidenced on MRI. In one of these subjects the MRI showed a permanently displaced disc in the contralateral TMJ. This TMJ showed no clinical signs, but the radiographic signs were severe. Of the 18 TMJs that could not be judged appropriately, the disc was not discernible either on the closed

or on the open mouth images in four cases. In eight casesthe disc, being thin and flattened, was detectable in an anterior position on the closed mouth images, but could not be discerned on the open mouth images. In three cases the disc was detectable on the open mouth images,but could not be discerned on the closed mouth images. In these casesthe disc was seentwice in an anterior position and once in a normal position. In three cases,the disc was seenin an anterior position on the closed mouth images, but it was not clear whether it regained its normal position during opening because of poor quality of the open mouth images. Thus, anterior disc position was found in at least 13 of these TMJs. Severe radiographically detectable changes were found in 61% of these TMJs. Discussion

Thirty years after the retrospective diagnosis of osteoarthrosis and internal derangement, the only clinical signs in which former patients differed significantly from control subjects of the same age were maximal mouth opening and deviation on protrusion. Nevertheless, the interincisal distance at maximal mouth opening was more than 35 mm in 90% of the former patients. Furthermore, assessmentof translatory capacity on transpharyngeal radiographs did not show differences between TMJs of former patients and control subjects. However, radiographic signs of osteoarthrosis and internal derangement, such as deviation in shape, flattening, and sclerosis,were observed significantly more often in TMJs of former patients than in TMJs of con-

Table 8. Detectable Associated

Overall Extent of Radiographically Degenerative Condylar Changes With Disc Position Assessed on MRI N

Transpharyngeal No Slight Moderate Severe Transcranial No Slight Moderate Severe NOTE. differences spectively cording to vs PDD P respectively

RDD

PDD

20 6 1 2

(69.0) (20.7) (3.4) (6.9)

16 I 2 1

(61.5) (26.9) (7.7) (3.8)

3 6 10 21

(7.5) (15.0) (25.0) (52.5)

17 I 4 1

(58.6) (24.1) (13.8) (3.4)

17 5 4 0

(65.4) (19.2) (15.4) (0.0)

6 5 10 19

(15.0) (12.5) (25.0) (47.5)

Percent frequencies are given in parentheses. Significant in extent of radiographic signs on transpharyngeal retranscranial radiographs between groups divided acdisc position: N vs RDD P > .05 respectively > .05; N < .OOOO respectively < .OOOO; RDD vs PDD P < .OOOO < .OOOO.

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FIGURE 1. A, Transpharyngeal and B, transcranial radiographs of the left TMJ of a 60.year-old female control subject. radiographically detectable degenerative changes, and TMJ mobility is normal. The sagittal Tl-weighted MR images show position (arrowheads) in both C, closed, and 0, open mouth position.

trol subjects. In addition, the radiographically detectable degenerative changes in TMJs of former patients were more severe than those found in TMJs of control subjects. Recent studies in which disc position was determined by arthrography or MRI have shown that structural hard tissue changes occur predominantly in TMJs with permanent disc displacement and are seldom seen in TIvIJs with reducing disc displacement.“,12,2’ Our results are consistent with these findings. Even in TMJs in which reducing disc displacement was present for

OF THE

TMJ

There are no a normal disc

more than three decades, no or only slight radiographitally detectable degenerative changes were observed. The results of this study indicate that the classification criteria used to select TMJs with osteoarthrosis and internal derangement were highly accurate. In more than 90% of the TMJs with a history of osteoarthrosis and internal derangement, internal derangement was confirmed by MRI. In four TMJs of former patients, a normal disc position was found. Some other TMJ disorder closely resembling the clinical signs of internal derangement may have misled the

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FIGURE 2. A, Transpharyngeal and B, transcranial radiographs of a right TMJ of a 66-year-old female former patient diagnosed with a reducing disc displacement. There are no radiographically detectable degenerative changes, and TMJ mobility is normal. The sagittal Tlweighted MR images show an anteriorly displaced disc (arrowheads) in the C, closed mouth position, which regains its normal position atop of the condyle on opening (D).

observers or the disc may have returned to its “normal anatomic position.” The MR images of the contralateral TMJs of the patients also showed a high percentage of internal derangement. This might easily lead to the conclusion that the classification procedure was not quite as accurate as assumed previously. The position of the discs of the cases under study was not established by any imaging technique 30 years ago. In those days disc visualization was restricted to arthrography, which was a relatively new technique at the time.22 Its drawbacks,

such as invasiveness and radiologic risk, limited its use as a routine diagnostic too1.23-25However, the contralateral TMJs underwent the same classification procedure as the TMJs with a history of osteoarthrosis and internal derangement. Regardless of the current clinical and radiographic findings, 30 years ago no clinical and radiologic signs and symptoms indicative of osteoarthrosis and internal derangement were present in the contralateral TMJs. In agreement with other studies, we found a strong correlation between radiographically detectable degen-

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LlGURE 3. A, Transpharyngeal and B, transcranial radiographs of the left TMJ of a 66-year-old female former patient diagnosed with a permanent disc displacement. Deviation in shape, flattening, sclerosis, and exophyte formation of the condyle are seen on both radiographs. TMJ mobility is normal. The sagittal Tl-weighted MR images show an anteriorly displaced misshapen disc (arrowheads) in both the C, closed and, 0, open mouth position.

erative changes and the stage of internal derangement~“J2,21 In addition, Stegenga et al” found that clinical and conventional radiographic information was sufficient to differentiate between stages of osteoarthrosis and internal derangement. Thus, in our opinion, osteoarthrosis and internal derangement most likely developed in the intervening years on the contralateral side of former patients with unilateral complaints. Only six patients (27%) reported having noticed that signs and symptoms had developed in the con-

tralateral TMJ. None of them had requested treatment for these signs and symptoms. Apparently, in 73% of these cases, osteoarthrosis and internal derangement had developed subclinically. Subclinical or asymptomatic development of osteoarthrosis and internal derangement is not uncommon. However, its prevalence remains somewhat controversial until now. Recent imaging studies have shown frequenties of asymptomatic internal derangement varying from 15% to 60%. 26-30With the introduction of nonhazardous, noninvasive methods to visualize the

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disc, it will become easier to gain insight into this phenomenon in the near future. Several imaging studies have shown bilateral occurrence of internal derangement to be rather common. Frequencies varying from 50% to 65% have been repofled.27.2%31In our study, bilateral osteoarthrosis and internal derangement were also very common (71% of the patients), albeit asymptomatic unilaterally in most of the cases. Like asymptomatic osteoarthrosis and internal derangement, the prevalence of bilateral osteoarthrosis and internal derangement has remained uninvestigated until recently. This might be because of the lack of convenient and nonhazardous imaging modalities or, in fact, simply because of the often asymptomatic course of internal derangement and osteoarthrosis on one side. Basically, bilateral occurrence of osteoarthrosis and internal derangement should not be surprising, because both TMJs are interrelated by the mandible and function under more or less the same circumstances. This implies that they are prone to the same structural, genetic, constitutional, and psychologic causative factors. The question then remains why one TMJ becomes symptomatic and the other does not. Currently, methods to visualize the disc are widely available. With introduction of dual-surface-coil MRI equipment it has become easier and tempting to routinely scan both TMJs in patients with unilateral complaints. A prospective longitudinal study design, which includes regular bilateral imaging of persons with unilateral signs and symptoms, would be helpful to elucidate the problems that exist in understanding the subclinical development of osteoarthrosis and internal derangement of the contralateral TMJ in persons with unilateral complaints. In 18 TMJs, the position of the disc could not be assessed appropriately either in the open or closed mouth position, or both. In most cases, however, the disc was seen in an anterior position on one or more slices of either image. The anterior position, together with a badly misshapen configuration, seemed strongly indicative of a permanently displaced disc.32 In four TMJs it was impossible to discern any disc at all. Considering the high percentage of moderate to severe radiographic changes in this group (approximately 70%), the correlation between radiographic signs and disc position, and the high occurrence of bilateral displacement, it is probably safe to assume that in these cases the discs were displaced permanently as well. The difficulty in discerning the disc was presumably caused by degeneration of all the TMJ components. Perforation or even rupture of the disc or its attachments may very well be the cause of the severe degeneration in these cases. This study shows that 30 years after initial diagnosis of osteoarthrosis and internal derangement, clinical

signs of these disorders are scarce. Radiographically detectable degenerative changes appear to be almost exclusively limited to cases with permanent disc displacement. In TMJs with a reducing disc displacement, even if this condition is present for many years, radiographically detectable degenerative changes are unlikely to be found and, if present, are predominantly slight in nature. Bilateral osteoarthrosis and internal derangement is common, although clinical signs and symptoms of the disorders frequently develop only unilaterally. The asymptomatic course of osteoarthrosis and internal derangement suggests that the TMJ has a remarkable adaptive capacity. Therefore, when treatment is needed, the natural course of the disorder should be considered. References 1.

2. 3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

1.5.

Boering G: Temporomandibularjoint arthrosis: An

analysis of 400 cases. Thesis, University of Groningen, The Netherlands, 1966 Toller PA: Osteoarthrosis of the mandibular condyle. Br Dent .I 134:223, 1973 Rasmussen OC: Temporomandibular arthropathy: Clinical, radiologic and therapeutic aspects with emphasis on diagnosis. Int .I Oral Surg 12:365, 1983 Farrar WB, McCarty WL Jr: Inferior joint space arthrography and characteristics of condylar paths in internal derangements of the TMJ. J Pro&et Dent 41548, 1979 Dolwick MF, Katzberg RW, Helms CA: Internal derangement of the temporomandibular joint: Fact or fiction? J Prosthet Dent 49:415, 1983 Westesson PL, Rohlin M: Internal derangement related to osteoarthrosis in temporomandibular joint autopsy specimens. Oral Surg Oral Med Oral Path01 57:17, 1984 Wilkes CH: Internal derangement of the temporomandibular joint: Pathologic variations. Arch Otolaryngol Head Neck Surg 115:469, 1989 Helkimo E, Westling L: History, clinical findings and outcome of treatment of patients with anterior disk displacement. J Craniomandib Pratt 5:269, 1987 Lundh H, Westesson PL, Kopp S: A three-year follow-up of patients with reciprocal temporomandibular joint clicking. Oral Surg Oral Med Oral Path01 63530, 1987 Eriksson L, Westesson PL: Clinical and radiological study of patients with anterior disc displacement of the-temporomandibular ioint. Swed Dent J 7:55. 1983 Westesson”PL: Structural hard-tissue changes in temporomardibular joints with internal derangement. Oral Surg Oral Med Oral Path01 59:220, 1985 Brooks SL, Westesson PL, Eriksson L, et al: Prevalence of osseous changes in the temporomandibular joint of asymptomatic persons without internal derangement. Oral Surg Oral Med Oral Path01 3: 122, 1992 Nickerson JW, Boering G: Natural course of osteoarthrosis as it relates to internal derangement of the temporomandibular joint, in Merill RG (ed): Oral and Maxillofacial Surgery Clinics of North America, vol 1. Disorders of the TMJ 1: Diagnosis and arthroscopy. Philadelphia, PA, Saunders, 1989, pp 27-45 de Leeuw R, Boering G, Stegenga B, et al: Temporomandibular joint osteoarthrosis: Clinical and radiographic characteristics 30 years after non-surgical treatment: A preliminary report. J Craniomandib Pratt 11: 15, 1993 de Leeuw R, Boering G, Stegenga B, et al: Clinical signs of TMJ osteoarthrosis and internal derangement 30 years after nonsurgical treatment. J Orofacial Pain 8: 12, 1994

1280

DISCUSSION

16. de Leeuw R, Boering G, Stegenga B, et al: Symptoms of TMJ osteoarthrosis and internal derangement 30 years after nonsurgical treatment. J Craniomandib Pratt 13:81, 1995 17. de Leeuw R, Boering G, Stegenga B, et al: Radiographic signs of TMJ osteoarthrosis and internal derangement 30 years after non-surgical treatment. Oral Surg Oral Med Oral Path01 79:382, 1995 18. Stegenga B, de Bont LGM, van der Kuijl B, et al: Classification of temporomandibular joint osteoarthrosis and internal derangement. Part I: Diagnostic significance of signs and symptoms. .I Craniomandib Pratt 10:96, 1992 19. Tasaki MM, Westesson PL, Raubertas RF: Observer variation in interpretation of magnetic resonance images of the temporomandibular joint. J Oral Surg Oral Med Oral Path01 76:231, 1993 20. Van der Kuijl B, Schellhas KP, Mooyaart EL, et al: Temporomandibular joint magnetic resonance imaging: Reliability of articular disk visualization, in Van der Kuijl B: Evaluation of Imaging Techniques, Thesis, Groningen, The Netherlands, 1992, pp 51-67 21. Kirk WS Jr: A comparative study of axial corrected tomography with magnetic resonance imagery in 35 joints. Oral Surg Oral Med Oral Path01 68:646, 1989 22. Norgaard F: Arthrography of the mandibular joint. Acta Radio1 251619, 1944 23. Toller PA: Opaque arthrography of the temporomandibular joint. Int J Oral Surg 3:17, 1974 24. Kircos LT, Orthendahl DA: Magnetic resonance imaging of the TMJ, in Delbalso AM (ed): Maxillofac Imaging. Philadelphia, PA, Saunders, 1990, pp 675-695 25. Van der Kuijl B, de Bont LGM, Vencken LM, et al: Temporo-

26. 27.

28.

29.

30. 31.

32.

mandibular joint articular disc imaging: comparison of direct sagittal CT to MRI, in Van der Kuijl B: Temporomandibular Joint: Evaluation of Imaging Techniques, Thesis, Groningen, The Netherlands, 1992, pp 69-79 Kircos LT, Orthendahl DA, Mark AS, et al: Magnetic resonance imaging of the TMJ disc in asymptomatic volunteers. J Oral Maxillofac Surg 45:852, 1987 Sanchez-Woodworth RE, Tallents RH, Katzberg RW, et al: Bilateral internal derangements of temporomandibular joint: Evaluation by magnetic resonance. Oral Surg Oral Med Oral Path01 65:281, 1988 Westesson PL, Eriksson L, Kurita K: Reliability of a negative clinical temporomandibular joint examination: Prevalence of disk displacement in asymptomatic temporomandibular joints. Oral Surg Oral Med Oral Path01 68:551, 1989 Isberg A, Stenstrijm B, Isacsson F: Frequency of bilateral temporomandibular joint disc displacement in patients with unilateral symptoms: A 5-year follow-up of the asymptomatic joint: A clinical and arthrotomographic study. J Dentomaxillofac Radio1 20:73, 1991 Roberts C, Katzbeg RW, Tallents RH, et al: The clinical predictability of internal derangements of the temporomandibular joint. Oral Surg Oral Med Oral Path01 1:412, 1991 Paesani D, Westesson PL, Hatala M, et al: Prevalence of temporomandibular joint internal derangement in patients with craniomandibular disorders. Am J Orthod Dentofac Orthop 101:41, 1992 de Leeuw R, Boering G, Stegenga B, et al: TMJ disk position and configuration 30 years after the initial diagnosis of osteoarthrosis and internal derangement. J Oral Maxillofac Surg 531234, 1995

J Oral Maxillofac Surg 543280.1281, 1996

Discussion Hard and Soft Tissue Imaging of the Temporomandibular Joint 30 Years After Diagnosis of Osteoarthrosis and Internal Derangement Per-Lennart Westesson,MD, PhD, DDS University

of Rochester

Medical

Center,

Rochester,

New York

This report may give the impression that all patients should be treated with simple and conservative measures and that all of them will stay well for the next 30 years. This is different from the clinical experience of a regular practice where a certain percentage of patients with temporomandibular joint (TMJ) problems do not get better, do not respond to simple treatment methods, and continue to require additional treatment. So how do we explain the discrepancy between the findings of this follow-up study and day-to-day clinical practice? First we must look at the sample. The 46 patients investigated represent about 12% of the original 400 patients that were diagnosed and treated 30 years ago. They were selected for follow-up based on age criteria, availability, and willingness to undergo magnetic resonance imaging. This is a small sample size and from clinical experience we know that refractory TMJ patients constitute only a few percent of the entire TMJ population. Thus, if only one or two pa-

tients would have had a different outcome, this would significantly affect the result. Therefore, it is likely that if a larger proportion of the initial 400 patients had been examined there would have been a few patients with persistent symptoms and a need for more extensive treatment. Secondly, the initial 400 patients may not have been exactly the same type as those who show up in an oral and maxillofacial surgeon’s office today. The patients may already have been preselected in such a fashion that those with milder symptoms may have been seen in this clinic and patients with more severe symptoms may have gone to a different setting. Thus both the initial patient selection and the patient selection at the time of follow-up may have biased the results toward patients with milder symptoms. If the clinic where the 400 patients were diagnosed and treated did not offer surgical treatment at that time, it is likely that those patients with severe symptoms went to another health care facility. Nevertheless, this study is still valuable because it documents that a significant proportion of TMJ patients probably have a favorable natural course or a favorable response to conservative treatment modalities. However, the results cannot be generalized to the entire TMJ population for the reasons described. One thing that should be learned from the study is that initial treatment for TMJ disorders should be kept at a minimum. Reassurance, dietary advice, exercise, heat, and pain