Joint Meniscus Research Articles

Computed tomographic evaluation of the density of the temporomandibular joint meniscus

Pathologic alteration of the articular disk, including moderate calcification within the meniscus proper, has been reported to occur in many cases of TMJ dysfunction with chronic anterior meniscal displacement. The purpose of this investigation was to measure, by means of direct sagittal computed tomographic scanning technology, the density (x-ray attenuation) of the meniscus. Fifty-two joints, shown to have meniscus displacement with or without reduction (MD/MDR), and 24 symptomatic joints with normal tomograms were evaluated with the use of a GE 8800 CT scanner. Mean attenuation values were extrapolated with the use of a symmetrical (1 to 9 pixels) region-of-interest (ROI) cursor. Density gradients of the masseter muscle, lateral pterygoid fat pad, and lateral pterygoid muscle were also obtained. The results of this study showed that the mean meniscal density values were 116.7 ± 4.2 Hounsfield units (HU) for MD subjects, 111.3 ± 4.6 HU for MDR subjects, and 82.4 ± 2.9 HU for subjects with symptoms. The MD and MDR density group means were significantly different ( p < 0.001) from the normal group means. A relative comparison of the meniscus density with that of the lateral pterygoid muscle, its fat pad, and the masseter muscle showed a consistent mean difference when the paired t test was used. Meniscal displacement was found to be associated with an increase in density gradient, which suggests histologic alteration.

Meniscocondylar plication: A modified operation for surgical repositioning of the ectopic temporomandibular joint meniscus: Rationale and operative technique

A historical review of temporomandibular joint (TMJ) surgical meniscal repositioning procedures is presented, and three operations that are currently used to manage this problem are compared and contrasted. Each operation produces iatrogenic deviations in intra-articular anatomy and retains the potential to create significant alterations in TMJ biomechanics. Meniscocondylar plication has been performed on 84 patients (89 joints) with arthrographically confirmed internal derangement of the TMJ. A 90.7% success rate was achieved. The operation is technically facile, surgically uncomplicated and clinically effective. It should rank as a justifiable and viable alternative to those operations that are presently being performed to treat patients with internal derangement of the TMJ.

CT number characteristics of malpositioned TMJ menisci. Diagnosis with CT number highlighting (blinkmode).

The use of computed tomography (CT) number highlighting ("blinkmode") for diagnosing malpositioned temporomandibular joint menisci was investigated. By determining the average CT number, standard deviation, and range for specific periarticular tissues, it is possible to tell how much their attenuation values overlap and, therefore, whether there is a sound basis for distinguishing the disc from adjacent tissues. Fresh and fresh-frozen cadaver specimens, were scanned in axial and direct sagittal planes with 1.5-mm thick overlapping soft-tissue sections. CT number measurements were made for tendon, muscle, fat, and meniscus. Patients also were scanned with overlapping 1.5-mm thick axial soft-tissue sections in order to compare the range of CT numbers in cadavers with that in living subjects. Cadaver joints were cryosectioned at 0.5-mm intervals in the same planes as their CT sections, and the tissue sections were compared with their respective CT highlighted sections. For patients the average CT numbers in Hounsfield units were 88 for tendon, 67 for muscle, -25 for fat, and 100 for meniscus. Fresh unembalmed cadavers showed a higher CT average number for tendon and a lower average CT number for fat. The anatomic sections confirmed the meniscal position seen in the highlighted sections in nine of ten joints (90%) and was equivocal in one. Misshapen and malpositioned discs are seen readily with the blinker function; thinned and normal discs are not. The tendinous insertion of the lateral pterygoid muscle may be confused for meniscus in the medial aspect of the TMJ.(ABSTRACT TRUNCATED AT 250 WORDS)

Posterior dislocation of the temporomandibular joint meniscus: report of three cases

The causes and symptoms of posterior dislocation of the TMJ meniscus are discussed in the context of three case reports. An original surgical technique is described for practitioners to repair the derangement.

Splint therapy evaluation with direct sagittal computed tomography

Splint therapy is often the initial nonsurgical treatment selected to manage patients who have anterior displacement of the temporomandibular joint (TMJ) meniscus. It is usually effective if the splint restores normal meniscocondylar relationships. An accurate method for assessing meniscocondylar relationships by means of direct sagittal computed tomography (CT) is described. The precise protocol for this noninvasive CT method and the criteria used to interpret the CT images are presented.

Increased collagenase activity in human rheumatoid meniscus.

Collagenase activity of the knee joint menisci of patients suffering from rheumatoid arthritis was approximately 3-fold higher than that found in menisci of control patients. The mean collagenase activity in the macroscopically more diseased parts of the rheumatoid menisci was significantly higher than that in the less damaged areas. The specific degradation products resulting from the cleavage of human meniscoid type II collagen by rheumatoid meniscoid collagenase were demonstrated by SDS-polyacrylamide gel electrophoresis. Addition of N-ethylmaleimide, which activates latent mammalian collagenases, did not further increase collagenase activity in rheumatoid menisci. Thus in rheumatoid meniscus, collagenase may be synthesized and then activated, probably by proteolytic enzymes involved in the inflammatory reaction.

Repair of the adult temporomandibular joint meniscus with an autogenous dermal graft

A surgical procedure for the successful repair of the temporomandibular joint meniscus is described. Twenty-three patients have been treated by this procedure, with both objective and subjective improvement. The procedure is accomplished with minimal technical difficulty and minimal cosmetic defect.

Magnetic resonance imaging of the temporomandibular joint meniscus

This report describes early experience with magnetic resonance imaging (MRI) of the temporomandibular joint meniscus in which surface coil technology was used. The results suggest remarkable imaging capabilities and speed with noninvasive methods.

Dislocation of the temporomandibular joint meniscus: Contrast arthrography vs computed tomography

Dislocation of the temporomandibular joint meniscus: Contrast arthrography vs computed tomography

Temporomandibular joint: magnetic resonance imaging.

Magnetic resonance (MR) imaging of the temporomandibular joint was performed in two subjects using a 1.5 T experimental imaging system equipped with a 6.5 cm surface coil antenna. Normal and pathologic anatomy were demonstrated with exquisite detail. Anterior displacement of the joint meniscus was clearly visible in the symptomatic subject, consistent with arthrographic confirmation.

Arthrographically assisted splint therapy

Occlusal splints are often constructed to aid in treatment of temporomandibular joint meniscus displacement. Techniques for arthrographically locating the point of meniscal displacement and for fabrication of an appropriate occlusal splint are described.

Descriptive anatomy of fibrocartilaginous menisci in the finger joints of the hand.

Observations were made from the dissection of 156 digital joints (thumbs excluded). In all joints fibrocollagenous menisci projected into the articular cavity from a ring-like structure based on the joint capsule. These meniscal structures separated the articulating cartilage surfaces at the margins of the joint. Histological examination confirmed a fibrocartilaginous nature of the tissue which demonstrated positive staining for proteoglycans and collagen fibers. Although generally similar in form, these meniscal structures varied in extent when compared between joint groups. The greatest amount and articular contribution was noted in metacarpophalangeal joints with least being found distally.

Computed tomography of the temporomandibular joint meniscus a report of preliminary tests

CT standard techniques have been used as a diagnostic tool to determine anterior meniscus displacement without reduction. 10 patients were examined to test the value of this technique in the daily routinework of a department of Radiology. The results are encouraging.

Three-dimensional imaging and display of the temporomandibular joint

Despite recent advances in diagnostic radiology, current techniques for radiographic evaluation of the temporomandibular joint continue to present the clinician with difficult problems in interpretation and diagnosis. The use of three-dimensional images reconstructed from computed tomographic (CT) data improves the diagnostic value of conventional CT at no additional risk to the patient and may provide new insights into this complex anatomic structure. A sequence of 1.5 mm CT sections is made with a slice-to-slice spacing of 1.0 mm. These are used to construct a new sequence of slices by mathematical interpolation in which the new slice spacing equals the size of the pixels. Structures to be imaged separately are then masked in the interpolated sections prior to “windowing” for the appropriate tissue density. A special algorithm detects the boundary surface of the selected structure. The surface pixels are assigned gray levels on the basis of their distance and attitude from the observer. When displayed, this produces a simulated three-dimensional image. The image can be rotated and sectioned. Rotations permit otherwise hidden surfaces to be examined. Images of a human temporomandibular joint in vitro are presented to demonstrate (1) the bony components of the joint and their relationships within the joint; (2) the bony components separated to display hidden surfaces; and (3) the joint meniscus in situ and as a separate component.

Temporomandibular joint internal derangements: CT diagnosis.

Two hundred patients with suspected displaced temporomandibular joint meniscus were studied with computed tomography. In 75 cases confirmation of the CT diagnosis was subsequently obtained via surgery or arthrography; correlation was found in 73 cases (97%), with one false-negative and one false-positive examination. When meniscus displacement was graded as "mild," "moderate," or "severe," those cases diagnosed as moderate or severe were more likely to require surgery. The technique and interpretation of this technique is described; in most cases CT can replace arthrography in diagnosing displaced temporomandibular joint menisci.

Chemical changes of human knee joint menisci in various stages of degeneration.

Human knee joint menisci graded according to degenerative alterations were submitted to chemical analysis. Normal menisci contained 72% water, 0.12% DNA, 22% collagen, and 0.8% total glycosaminoglycans with the following glycosaminoglycan distribution pattern: 40% chondroitin 6-sulphate, 10-20% chondroitin 4-sulphate, 20-30% dermatan sulphate, and 15% keratan sulphate. The water content increased with increasing degeneration, whereas the collagen and glycosaminoglycan contents decreased with relative increase of chondroitin 6-sulphate.

Diagnosis by computed tomography of temporomandibular joint meniscus displacement

CT may be a practical alternative to arthrography for diagnosing displacement of the meniscus in the TMJ. In a study of 75 patients, 69 were diagnosed by CT to have meniscal displacement. Thirty-four diagnoses were subsequently confirmed by surgery or arthrography. Disadvantages of CT are cost (almost twice as much as an arthrogram), inability to diagnose perforations, and inability to judge meniscus dynamics, which can be done by fluoroscopy. Advantages are patient comfort, safety, and decreased total radiation dose. Continued research and clinical correlation will be needed to determine the role of CT in the diagnosis of meniscus displacement of the TMJ. However, initial results are promising, and CT may quickly replace arthrography as the diagnostic procedure of choice.

Repair of the adult temporomandibular joint meniscus with an autogenous dermal graft

A surgical procedure for the successful repair of the temporomandibular joint meniscus is described. Twenty-three patients have been treated by this procedure, with both objective and subjective improvement. The procedure is accomplished with minimal technical difficulty and minimal cosmetic defect.

Perforations of the temporomandibular joint meniscus: Arthrographic, surgical, and clinical findings

Arthrographic examination of the temporomandibular joint for perforations of the meniscus was found to be a reliable diagnostic test in a retrospective review of 45 surgical cases. Clinically palpable crepitus was also found to be an accurate indicator of the existence of perforations in patients who could open beyond 26 mm. The combination of palpable crepitus and a positive arthrogram was found to be complementary in diagnosing perforations and was confirmed by surgical observations.

Computed tomography of the temporomandibular joint meniscus

Fifteen patients with temporomandibular joint dysfunction were examined by computed tomography using standard CT techniques. The data obtained were evaluated and correlated with arthrographic findings or surgical observations. CT scans may become a valid alternative to the often painful procedure of arthrography for assessment of temporomandibular joint pathology if the potential pitfalls are avoided.