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Results for “Condylar position”

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PubMed1999

In vivo determination of condylar lift-off and screw-home in a mobile-bearing total knee arthroplasty.

Twenty subjects implanted with the low-contact stress (LCS) cruciate-sacrificing, mobile-bearing total knee arthroplasty underwent dynamic videofluoroscopy during in vivo weight-bearing conditions using a 3-dimensional computer-aided design (CAD) interactive modeling method. Ninety percent of the subjects demonstrated significant lift-off during stance phase of gait. Condylar lift-off was present at both the medial and the lateral condyles. The maximal medial lift-off was 2.12 mm, whereas the greatest lateral lift-off was 3.53 mm. The maximal positive screw-home was 9.6 degrees, whereas the maximal negative or reverse screw-home was 6.2 degrees. The average screw-home rotation was positive 0.5 degrees. In 50% of patients, medial condylar translation was unexpectedly greater than lateral condylar motion. Condylar lift-off and screw-home motion are significant kinematic functions in this rotationally unconstrained total condylar knee arthroplasty.

Arthroplasty, Replacement, Knee↗

PubMed2005

A comparative study of unilateral dislocated mandibular condyle fractures in the rabbit.

PURPOSE: The purpose of this study was to clarify the influence of patients age and the degree of dislocation on the healing of mandibular condyle fractures. MATERIAL AND METHODS: Sixty-two Japanese white rabbits (30 adolescent and 30 adult ones) were used. They underwent unilateral condylar neck osteotomy. The proximal fragments were positioned differently. In group I animals, the fragments were reduced into the original position, in group II animals the small fragment was dislocated 55-90 degrees to the ramus. In group III animals the proximal fragment was dislocated 135 degrees to the ramus. Gross and microscopic assessment was performed 4, 6, 8, 12 and 24 weeks postoperatively. RESULTS: In adolescent animals, complete healing of the fracture was observed, irrespective of the degree of dislocation. In the adult animals, there was complete healing of the fractures in groups I and II. In group III animals, there was a decrease of ramus height accompanied by some fibro-cartilaginous changes. CONCLUSION: Even in rabbits condylar deformation has been found following heavily dislocated artificial condylar fractures in adult animals. This result will help to decide for or against surgical treatment of condylar fractures in humans.

Age Factors↗

PubMed1988

Mechanism of adaptation in the mandibular condyle of the mouse. An organ culture study.

The cranial base and whole mandible of 7-day-old mice were cultured for 1 or 2 weeks in a novel organ culture system that provided an articulating movement for the temporomandibular joints. The mandibles were articulating either in a closed or in an open position to simulate the in vivo mouth-breathing pattern. The reactions of the condylar processes were followed macroscopically and microscopically after osteoid or von Kossa staining. After 1 week of culture, small differences were found in the shape of the condylar processes between the two groups. After 2 weeks, significantly increased growth was observed superiorly in those condyles which had been working in a closed position and posteriorly in the condyles which had been working in an open position. Histologic analysis revealed that after 1 week calcification had proceeded faster in the posterior aspect of the condyles in the mandibles which had been working in a closed position as compared to the mandibles which had been working in an open position, and the difference was even more marked after 2 weeks. In the latter condyles calcification had proceeded markedly in the anterosuperior aspect. Osteoid staining showed that perichondrial mesenchymal cells had differentiated into osteoblasts in the posterior aspect of the condyles in those mandibles which had been working in a closed position. This led to a ceasing of expansive growth in the posterior aspect and thus to a more upwardly directed condylar growth. In mandibles which had been working in the open position to simulate the mouth-breathing pattern in vivo, chondrogenesis and thus expansive growth continued in the posterior aspect, leading to a more posteriorly directed condylar growth.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2006

The influence of masseter activity on rat mandibular growth.

Many studies have shown that mandibular and condylar growth is affected by compressive forces on mandibular bone and the condyle. It has been reported that chondroblastic differentiation and proliferation in chondrocytes play important roles in condylar growth. However, the influence of reduced compressive force on chondroblastic proliferation and mandibular bone formation is not fully understood. Thirty-six 3-week-old male Wistar rats were used in this study. In the experimental group, the masseter muscles were bilaterally resected to evaluate the influence of masticatory force on mandibular and condylar bone morphology. Six weeks after the operation, while the rats were in the pubertal growth stage, lateral X-rays were taken to analyze the skeletal pattern of the mandible. The form of the condyle and the thickness of the chondroblastic layers were evaluated by toluidine blue staining. Chondroblastic proliferation was identified by insulin-like growth factor-1 receptor (IGF-1r) immunostaining and bone resorption of the condyle was assessed by measuring tartrate-resistant acid phosphatase (TRAP) activity. Lateral X-rays of the mandible showed that rats in the experimental group tended to have large mandibular plane angles. The chondroblastic layer in the condyles of the experimental group rats was thinner than in the control group. The expression of IGF-1r immunopositive cells in the experimental group was significantly lower than in the control chondrocytes, and the number of TRAP-positive cells was significantly higher in the condylar bone of the experimental group. We conclude that masseter muscle activity is closely related to mandibular morphology during growth.

Acid Phosphatase↗

PubMed2003

Condylar erosion and disc displacement: detection with high-resolution ultrasonography.

PURPOSE: Our goal was to determine the feasibility of high-resolution sonography for the detection of condylar erosion and associated disc displacement at the temporomandibular joint (TMJ) condyle. MATERIALS AND METHODS: Forty-eight consecutive patients (96 joints) with TMJ disorders were investigated prospectively using a 12.5-MHz array transducer. Images were assessed for condylar erosion and disc displacements. Sonographic findings were correlated with those of magnetic resonance imaging (MRI). RESULTS: At MRI, 18 osseous changes were diagnosed with condylar erosion. Sonographically, 15 of the 18 condylar erosions were diagnosed correctly. Sensitivity, specificity, and accuracy of sonography in the depiction of condylar erosion were 83%, 63%, and 67%, respectively. The positive predictive value was 34%, and the negative predictive value was 94%. Disc displacement without reduction (43 of 96) and disc displacement without reduction concomitant with condylar erosion (16 of 96) were detected with an accuracy of 93% and 80%. CONCLUSION: Sonography is an insufficient imaging technique for the detection of condylar erosion. Assessment of disc displacement without reduction may be reliably made with sonography.

Adolescent↗

PubMed2004

Asymmetry in the condylar long axis and first molar rotation.

Asymmetric growth occurs frequently in the mandibulofacial region, but little attention has been given to asymmetry in the temporomandibular joint. The purpose of this study was to clarify the feature of asymmetry in the condylar long axis and its relation to upper first molar rotation. Records of 148 pre-orthodontic patients were used. The angle of the condylar long axis and that of the molar rotation were both larger on the left side than on the right side. Positive correlations were found between the corresponding bilateral measurements of condylar long axes and also between those of molar rotations, whereas no correlation was found between the condylar long axis and molar rotation. These findings were found in most subgroups classified by dental age, skeletal pattern, bite force balance, or gender. These results suggest that consistent left-right differences in the condylar long axis and first molar rotation are common.

Adolescent↗

PubMed1989

Relationship between jaw muscle volume and craniofacial form.

To study the relationship between craniofacial form and jaw muscle function, we evaluated 25 adult male subjects with Obstructive Sleep Apnea (age, 30-61 years; weight, 58-122 kg) on the basis of CT scans obtained for routine diagnostic purposes. All scans were obtained with the Frankfort horizontal plane at right angles to the floor; each CT slice was 8 mm thick. Masseter and medial pterygoid muscle outlines were traced, digitized, and stored, and three-dimensional reconstructions were made for calculation of muscle volume. Lateral cephalometric radiographs were analyzed for quantification of selected craniofacial variables. Significant correlations could not be identified between physiological apnea variables and jaw muscle volume. An intersubject variability in masseter muscle volume was identified (range, 22.4-38.1 cm3). Medial pterygoid muscle volume revealed more variability (range, 7.4-15.2 cm3). Masseter muscle volume had a negative correlation with mandibular plane and gonial angle, and a positive correlation with posterior face height, ramus height, posterior face length, condylar center to first molar point length, gonion to pterygomaxillary fissure length, and the ramus height/anterior face height ratio. Medial pterygoid muscle volume showed a positive correlation with posterior face height, ramus height, posterior face length, and the lengths between condylar center to first molar contact point, gonion to pterygomaxillary fissure, and antegonion to key ridge. Subjects with large masseter and medial pterygoid muscle volumes had flat mandibular and occlusal planes, and small gonial angles.

Adult↗

PubMed2000

Histological changes in the rabbit condyle following posterolateral disk perforation.

PURPOSE: To examine changes in condylar cartilage following perforation in the posterolateral region of the articular disk of the craniomandibular joint of a rabbit. MATERIAL AND METHODS: The circular perforation in the left joint of 25 female Japanese white rabbits measured precisely one-sixteenth of a disk. Histological examination, including the immunohistochemical proliferating cell nuclear antigen (PCNA) procedure, was performed on separate sets of five rabbits each 2, 4, 8, 12, and 24 weeks postoperatively. RESULTS: Microscopic examination revealed hypertrophy of the condylar cartilage with osteophyte formation up to 8 weeks after perforation. Proliferative activity then decreased near the condylar surface as the perforation flattened. Twenty-four weeks postoperatively, the condylar surface was found to be fibrous and flattened. Positive PCNA results in cartilage cells indicated proliferation following disk perforation which peaked in the 4th week and then decreased. CONCLUSION: Disk perforation was followed initially by hypertrophy of condylar cartilage, and later by degeneration of the condylar surface. Although osteoarthritic cartilage was found 24 weeks after perforation, degeneration decreased over time. This suggests that remodelling took place after the perforation.

Animals↗

PubMed1989

Electron microscopic study of condylar cartilage of rat mandible stained with ruthenium red: proteoglycans and hypertrophic chondrocytes.

Ultrastructure of hypertrophic chondrocytes and extracellular matrix in condylar cartilage of rat mandible was studied in conjunction with ruthenium red staining. Special care was given to the preservation of proteoglycans in the extracellular matrix. Ruthenium red-positive granules were observed in the pericellular matrix of condylar chondrocytes, and their size and number increased around the hypertrophic cells. However, these granules disappeared in the lowest hypertrophic zone, in which uncalcified cartilage matrix was also disintegrated prior to initiation of ossification. Moreover, hypertrophic chondrocytes observed at the lowest zone appeared intact in their ultrastructural features, i.e., containing numbers of lysosomes and coated vesicles in the cytoplasm facing the blood capillaries. The results strongly suggest that the lowest hypertrophic chondrocytes in rat condylar cartilage may have an active role in the degradation and resorption of the pericellular matrix, especially proteoglycans, and uncalcified matrix, which changes seem an essential step for the initiation of endochondral ossification.

Animals↗

PubMed1988

Sagittal plane positioning of the femoral component in total knee arthroplasty.

The authors evaluated 623 total knee arthroplasties to determine the relationship between sagittal plane position of the femoral component and the final range of motion of the prosthetic knee. Two different prostheses were evaluated (Posterior Cruciate Condylar and A.G.C.) radiographically and functionally. Variation in sagittal plane position ranged from 20 degrees flexion to 20 degrees extension. No correlation between the sagittal plane position of the femoral component in either prosthesis and the final knee range of motion could be found. Sagittal plane femoral component position in the prostheses studied did not affect final range of motion when component position was between 20 degrees flexion and 20 degrees of extension.

Femur↗

PubMed2006

Influence of different condylar and incisal guidance ratios to the activity of anterior and posterior temporal muscle.

OBJECT: Few studies quantify reactions of masticatory muscles during clenching at different occlusal positions in individuals with different anterior and posterior guidance relationship and different number of working-side occlusal contacts. The hypothesis that altered incisal guidance (IG) and a different number of working-side occlusal contacts in complete denture wearers (CDW) change a pattern of temporal muscle activity and loadings to the mandible during clenching in incisal and lateral positions was tested. DESIGN: EMG activity during clenching in incisal (IP) and left (LOP) and right lateral occlusal (ROP) positions was compared between dentate subjects (DS) with steeper IG than condylar guidance (PG) and canine or canine+first premolar guidance in laterotrusive movements with CDWs who had steeper PG than IG and group function. EMG values were expressed as percentages of maximum voluntary clenching in maximum intercuspation (ICP) in each individual. RESULTS: The CDWs exhibited significantly higher posterior temporal muscle (TP) activity in IP and during lateral biting on mediotrusive side than DSs. Their coronoid process had to be pulled backward by TP fibers to rotate condyle in a counter-clockwise direction (PG>IG); contrary DSs had to rotate condyle in a clockwise direction to compensate for vertical overlap (IG>PG). Group function allowed more working-side contacts in CDWs and significantly higher anterior temporalis (TA) activity. CONCLUSION: Alteration of IG-PG ratio and a number of occlusal contacts during lateral clenching change a pattern of TA and TP activity in CDWs and a direction of mandibular loadings, although age related changes might also be responsible.

Adult↗

PubMed1999

Temporomandibular joint reconstruction in children using costochondral grafts.

PURPOSE: The aim of this study was to evaluate the postoperative growth of the mandible after reconstruction of the condylar process using costochondral grafts in children. PATIENTS AND METHODS: Temporomandibular joint (TMJ) ankylosis was surgically treated and the joint reconstructed with a costochondral graft (CCG) in two boys and eight girls with a mean age of 7.4 years. Two children had bilateral ankylosis. Postoperative changes and craniofacial growth were monitored by lateral and posteroanterior (PA) cephalograms annually from 2 to 6 years (mean of 4 years). RESULTS: Postoperatively, in the eight children with unilateral TMJ reconstruction, the mandible (Co-Gn) grew an average of 14.7 mm in length on the affected side and 15.1 mm on the nonaffected side; ramus length (Co-Go) increased an average of 7.1 mm on the affected side and 7.3 mm on the nonaffected side. However, in five of the children the chin progressively deviated toward the nonaffected side after TMJ reconstruction. The CCGs tended to have a more vertically directed condylar growth pattern and a more laterally positioned condyle. In the two cases with bilateral TMJ reconstruction, the CCGs grew until there was a mandibular prognathism that required orthognathic surgery to set back the mandible. CONCLUSIONS: Using CCGs to reconstruct TMJ ankylosis in children provides a functional condyle with growth potential. However, there is a possibility of excessive growth of the graft, resulting in deviation of the chin and mandibular prognathism years later.

Ankylosis↗

PubMed2002

Diagnostic image analyses of activator treated temporomandibular joint in growth and maturing stages.

This study evaluates the condylar response to activator in growth and in maturing patients using radiographs and magnetic resonance images (MRI). Seven patients (four in growth and three in maturing stages) treated for mandibular distal occlusion were studied. In all seven patients, lateral roentgen cephalograms, panoramic radiograms, and MRIs were made before and following functional treatment. All patients' mandibles advanced during treatment. Downward and forward mandibular growth was observed by superimposition of lateral cephalograms. On the condylar posterosuperior regions for both groups, double contours were sometimes observed on the panoramic radiograms following therapy. These double contours coincided with an area of high intensity in the MRIs for both groups. In the mature adult group, the double contours were more clearly observed when compared with those in the growth group. There were differences in the condylar adaptation types between the growth and mature development stages. Condylar adaptation to the newly created mandibular position was nevertheless found even in adult patients.

Activator Appliances↗

PubMed1993

A new surgical technique for old ununited lateral condyle fractures of the humerus in children.

It is difficult to achieve an anatomic reduction of old lateral condyle humeral fractures in spite of extensive excision of fibrous tissues from the condylar fragment. The long-standing displaced position of the condyle is responsible for the contracture of the origin of the common extensor tendon, which prevents anatomic reduction. In our technique, lengthening of the common extensor origin was done and anatomic reduction achieved. This technique has been tried successfully in 15 cases of neglected fractures of lateral humeral condyles in children.

Child↗

PubMedDate not supplied

Nonunion of slightly displaced fractures of the lateral humeral condyle in children: an update.

Inadequate treatment continues to be the leading cause of nonunion of slightly displaced fractures of pediatric lateral humeral condyles, despite references to prevention in the orthopaedic literature. In most cases, the elbow was established nonunion can be salvaged by early stabilization and bone grafting, provided that the fragment is in acceptable position and the growth plate of the condylar fragment is open. Procrastination may allow the physis of the condylar fragment to close prematurely, preemptying the golden opportunity to salvage the child's elbow. The author has collected 23 similar cases from correspondence with 17 orthopaedic surgeons.

Adolescent↗

PubMed1997

Temporomandibular joint osseous morphology in a consecutive sample of ankylosing spondylitis patients.

OBJECTIVE: To evaluate temporomandibular joint (TMJ) osseous morphology in a consecutive sample of Mexican patients with ankylosing spondylitis. METHODS: Consecutive patients with a diagnosis of ankylosing spondylitis who attended two secondary care outpatient rheumatology clinics were included in the study. Patients had a rheumatological assessment using a structured questionnaire and examination. Recorded variables included demographic data, disease characteristics, TMJ symptoms, and axial mobility measurements. Hypocycloidal tomography of the TMJ was obtained on all subjects. Radiographic variables included condyle position, superior joint space, range of movement, condylar osseous changes, and temporal osseous changes. Patients also underwent standard cervical spine radiography. A control group of normal people without either TMJ symptoms or systemic rheumatic disease was obtained. RESULTS: 65 subjects were studied (65 right sided and 63 left sided tomograms). The control group consisted of 22 individuals. Both groups were similar in age [33 (SD 11) v 34 (9) years, P = 0.8]. Patients with ankylosing spondylitis had more variability in TMJ mobility than controls (P < 0.05) and showed increased frequency of condylar erosions (P < 0.01), flattening (P < 0.01), sclerosis (P < 0.01), and temporal flattening (P < 0.01). Condylar erosions were associated with longer duration of ankylosing spondylitis (P < 0.05), neck complaints (P < 0.05), and atlantoaxial subluxation (P < 0.05). CONCLUSIONS: TMJ involvement is frequent in this population of patients with ankylosing spondylitis and is associated with variables that suggest more severe disease.

Adult↗

PubMed1999

[Image analysis of condylar cartilaginous adaptation to mandibular protrusion in rats].

OBJECTIVE: To quantify chondrogenesis in condylar cartilage in response to active forward positioning of mandible. METHODS: Identical bite-jumping appliances were fixed to upper incisors of animals in experimental groups, causing a continuous mandibular forward positioning. Histological sections were performed through mandibular condyle and were stained with HE under the same condition. Chondrogenesis was quantified by measuring the area of cells in resting, proliferative, hypertrophic and erosive zones in the superioposterior region, through computer-assisted image analyzing system (Q550IW, Leica) with the advanced software (Leica Qwin Pro, V2.2). Statistical analysis was performed with GraphPad 3.0. RESULTS: 1. comparison among experimental groups revealed a fluctuation in proliferative zone, with 21-day group being the greatest (0.058 +/- 0.004 mm2) and 14-day the least (0.012 +/- 0.001 mm2). A change in erosive zone was also depicted by a peak of 0.112 +/- 0.001 mm2 in 7-day group and a bottom of 0.018 +/- 0.002 mm2 in 14-day group (P < 0.001). 2. comparison among the control groups manifested stable zonation, except for a slump of proliferative zone descending from 0.069 +/- 0.005 mm2 in 3-day group to 0.009 +/- 0.001 mm2 in 21-day group (P < 0.001). 3. comparison between experimental and control groups demonstrated significant discrepancy in proliferative zone, hypertrophic zone and erosive zone (P < 0.001). CONCLUSION: Mandibular forward positioning stimulates and accelerates cartilaginous remodeling in mandibular condyle.

Animals↗

PubMed1990

[Conservative treatment of perforated disks].

Stereognathographic recordings were taken of the mandibular movements of 11 patients who had undergone conservative treatment for unilateral disk perforation. The results showed a significant decrease in the condylar inclination angle of the affected joints. Based on these values the condylar inclinations were increased in a condyle positioning simulator (CPS). This allowed production of individually correct occlusal splints. In all cases studied this splinting therapy eliminated pain and crepitus.

Adult↗