 Today we shall be discussing condylar fractures under the headings, anatomy of TMJ, mechanism of condylar injuries and classification of condylar fractures. Let us have a quick look at the anatomy of Temporomandoblar joint. TMJ basically has two components, a passive component and active component. Passive components are the glenoid fossa which is a part of the temporal bone, condyle which is part of the mandible and articular eminence, capsules and ligaments and articular disc. These five are the passive components of TMJ of which the glenoid fossa, condyle and articular eminences are made up of bones or heart tissue and the capsules and ligaments and the disc are made up of soft tissue. The active components of Temporomandoblar joint are the muscles of mastication, all the muscles of mastication, the temporalis muscle, medial and lateral tergoid and mesater. All these fall under the active components of TMJ. TMJ is formed by the mandibular condyle fitting into the mandibular fossa and the two bones are separated by articular disc. The different capsular and ligament attachments are the fibrous capsule. Fibrous capsule or the joint capsule covers the entire joint. Temporomandoblar or lateral ligament. It extends from the zygomatic process to the lateral aspect of condylar head. Spenomandoblar ligament is an accessory ligament that extends from the spinal spinae to the tip of lingula on the medial aspect of the ramus. Stylomandibular ligament is the fourth ligament which extends from the styloid process to the posterior border of ramus at the angle region. So these four structures have attachments to and around the TMJ and their main function is to control the excessive movement or to guide the direction of the condylar head and articular disc during the movement or functioning of TMJ. In the lecture on basics of management of mandibular fractures, we had seen how elevators and depressors act on a fracture to displace it. Latval tergoid has direct attachment to the anterior part of the neck of the condyle at the tergoid fovea and it can displace the fractured condylar head anteriorly and medially. The condylar head is a semi-cylindroid process which is 15-20mm in length and 8-10mm in thickness. The long axis of the condyle is related to the position of the ramus of mandible and not to the skeleton. It is not related to the skeletal axis but it is related to the ramus of the mandible. The angle formed by the two condylar axes varies between 145 degree to 160 degree. This is an axial section of the CT showing cross sections of condyles on both the sides. So it is told that it is found out that the two condyles meet at the furamen magnum at an angle of 145 to 160 degrees. The vascular supply to the TMJ arises anteriorly from the mesotvic artery and posteriorly from the branches of superficial temporal and maxillary arteries. All these are the branches of external carotid artery. The nerve supply to the joint is from the auricular temporal nerve with some additional innervation from mesotvic nerve and deep temporal nerves. These diagrams depict the anatomical and histological differences between the condylar heads of a child and an adult. As you can observe, the cortical bone thickness at the condylar head in a child is very less when compared to that in an adult. The periosteum of the condyle facing the joint is in its active osteogenic state in a child whereas it has moved to the latent osteogenic state in an adult. Condylar neck in a child is broader with thin articular surface. Therefore, an impact at the condyle will confine the fracture within the capsule or it is called intracapsular fracture with hematrosis meaning bleeding and swelling within the joint. This carries a high risk of progressing into TMJ ankylosis. On the other hand, in an adult, the condylar neck is relatively narrow and the articular surface is thicker hence an impact to the condyle will result in extracapsular fracture with normal vascularity. Injury to the condyle may be caused by a variety of mechanisms. Lindal divided traumatic forces causing condylar injury into three categories. The first is energy imparted on a static individual by a moving object. For example, a blow to the face by a fist or a bat or any other object. The second type of force is that of a moving individual striking a static object such as a child falling and hitting the chin against the pavement. This mechanism is also seen in pariet ground fracture wherein a standing soldier collapses hits the chin onto the ground and fractures his condyle or mandible. The third classification is energy developed by a combination of the first two mechanisms. This type of force is typical of that generated during an automobile accident in which the individual is moving forward and the object is moving in the opposite direction. For example, where a person is moving in a car and hitting his chin across the dashboard. There have been many studies into the resistance of mandible. This diagram shows the deformation of bone by an applied force. When a force causes compressive strain at one side, it gets converted into tensile strain at another. It was found that bones fracture at sides of tensile strain because their resistance to compressive force is greater. These by Huell Kahn Hodson showed that isolated mandible is liable to particular pattern of distribution of tensile strain when forces are applied to it. Anterior forces applied to the symphysis mentai, the mental famine or mandibular body gets converted into strain at condylar necks and the lingual plates on the contralateral side. The areas in red denote the force applied and the areas in blue denote the resultant tensile strain. The subcondylar fracture as you can see in this diagram is usually a result of indirect violence to the mental prominence or the contralateral body of mandible. As you already know the mesater has insertion at the lateral aspect of ramus. The medial teregoid has insertion at the medial aspect of ramus and lateral teregoid is inserted at the teregoid phobia at the anterior neck of condyle. So usually a subcondylar fracture is evident just superior to the insertion of mesater. Therefore a coordinated action of the mesater and the teregoids will displace the condylar head in supido anterior and medial direction. Moving on to classification of condylar injuries. There are basically three types of injuries seen in temporal mandibular joint. They are contusion, dislocation and fracture. Contusion involves soft tissue injuries like that to ligaments, muscles, synovium and may cause formation of inflammatory exudates or hemarthrosis. A tear in meniscus can also result in osteoarthritic changes. Dislocation is a displacement of the condylar head completely out of the glenoid fossa which usually cannot be reduced by the patient. There is one more term associated with it, it is called subluxation. In subluxation patient can reduce the displaced condylar head himself. And fracture can either be intra-capsular, that means within the capsule like seen in majority of condylar fractures in children and also extra-capsular or sub-condylar fractures as seen in adults. Different classification systems have been given by various authors. Here we shall be discussing two such systems in detail. The first system was given by Lindahl in the year 1977. He proposed a system that classified condylar fractures based on several factors like based on anatomic location of the fracture, based on the relationship of the condylar segment to the mandibular fragment and based on the relationship between the condylar head and glenoid fossa. Let's see each of them in detail. Based on anatomic location of the fracture, he classified condylar fractures into fractures of the condylar head, condylar neck and sub-condylar fractures. The condylar head is usually defined as the portion of the condyle superior to the narrow constriction of the condylar neck. Fractures of the condylar neck are intra-capsular, means it is within the confinement of the fibrous capsule. The next classification is that of condylar neck. The neck is the thin constructed area located immediately below the condylar head. Therefore, it is extra-capsular. Any fracture at or below the condylar neck is considered extra-capsular fracture. Sub-condylar fracture. So sub-condyle is the region located below the condylar neck and extends from the deepest point of the sigmoid notch anteriorly to the deepest point along the concave posterior aspect of the ramus. So depending on the location, these fractures are described as high or low sub-condylar fractures. Now based on the relationship of the condylar segment to the mandibular fragment, fractures are classified as undisplaced or non-displaced. That means even if there is a fracture, the condylar head does not displace itself. So this is undisplaced fracture, deviated. This involves only an angulation of the condylar fragment in relation to the mandibular segment. As you can see in the diagram, there is only a little bit of angulation of the condylar fragment. The fractured ends remain in contact with no separation or overlap. This is deviated fracture. Displacement with medial or lateral overlap. Here the fractured ends of the condylar segment lies either medially or laterally to the displaced of the distal mandibular segment. Medially displaced condylar fragment is more commonly seen. Displacement with anterior or posterior overlap. As you can see in the diagram here, the condylar head is displaced anterior to the mandibular segment. Or it can be displaced posteriorly also but it is very rare. And the sixth type is no contact. Here there is no contact at all between the condylar fragment and the mandibular distal fragment. So this is the classification of condylar fractures under the category based on the relationship of condylar segment to the mandibular fragment. Based on the relationship between the condylar head and the glenoid fossa, it can be classified as non-displaced, displaced and dislocated fractures. In non-displaced fracture, the condylar head is in normal relation to the glenoid fossa. As you can see here, the relationship between the condylar head and the glenoid fossa remains the same. In displaced fractures, the condylar head remains within the confinement of the fossa but there is alteration in the joint space. The normal anatomy is not being seen here, there is displacement or there is change in the relationship between the condylar head and the glenoid fossa, there is change in the joint space. And in dislocated fractures, the condylar head lies completely outside the fossa. The usual location of dislocation is antedomedial due to the pull of the lateral tigol. So this is how Lindahl has classified condylar fractures based on the anatomic location of fracture based on relationship of the condylar segment to mandibular fragment and based on the relationship between the condylar head and the glenoid fossa. Another classification of condylar fractures was given by MacLennan in the year 1952. His system consists of four divisions, type I fracture or non-displaced fracture. As you can see in the diagram here, the fracture is non-displaced, type II fracture or fracture deviation. This type consists of simple angulation of the fracture segment without overlap or separation. This type includes the green stick fracture which is common in children. Type III fracture or fracture displacement. Here the fracture is characterized by overlap of the proximal and distal fracture segments. The overlap can be anterior, posterior, lateral or medial, but medial displacements are more common. Type IV fracture is fracture dislocation. Here the condylar head is completely outside the glenoid fossa, therefore it is complete extra-capsular fractures. Again the dislocation may be medial or lateral, anterior or posterior. So this is all about classification of condylar fractures. So we have seen in today's lecture the anatomy of TMJ, the mechanism and classification of condylar fractures. In the next lecture we shall be discussing in detail about the management of condylar fractures. Thank you. Continuing with condylar fractures, today we shall look into the clinical features, investigations and management of fractures of mandibular condyle. Let's see the clinical features associated with unilateral condyle fracture. There is often swelling and tenderness over the TMJ area of the affected side. There is hemorrhage from here on the same side which results from laceration of the anterior wall of external auditory meridus. Here it is important to distinguish bleeding originating in the external auditory canal from the middle ear hemorrhage. In middle ear hemorrhage it indicates a fracture of the petrous temporal bone and this may be accompanied by cerebrospinal autoria. That means escape of cerebrospinal fluid through the ear, it is known as cerebrospinal autoria. You will also find achemosis of the skin just below the mastoid process on the same side. This particular physical sign also occurs with fractures of the base of the skull and it is known as battle sign. If the condylar head is dislocated medially and after all the edema has subsided due to passage of time, a characteristic hollow over the region of the condylar head is observed. So this is characteristic of unilateral condylar fracture. During opening the mandible deviates towards the side of the fracture. That means deviates towards the affected side. There is unilateral posterior cross bite. Displacement of the condyle from the fossa or if the fractured condylar neck is overriding, then it causes shortening of the ramus on the same side and produces gagging of occlusion on the same side molars. There is also limited or painful protrusion or excursion. This means while the mandible is being deviated to the opposite side, it is painful. In bilateral condylar fractures, all the signs and symptoms present in unilateral fractures may be present on both the sides. And overall the mandible movement is more restricted than in unilateral fractures. If there is a displacement of the condyles from the glenoid fossa or overriding of the fractured bone ends, then an anterior open bite is present. Pain and limitation of opening and restricted protrusion is present in case of bilateral fractures also. Bilateral condylar fractures are frequently associated with fracture of the symphysis and parasymphysis. So the appearance of an elongated face may be result of bilateral sub-condylar fracture. Here is a diagrammatic representation of the characteristic disturbances of occlusion after condylar injury. As you can see in the first diagram, this is a post-chromatic effusion or hemarthrosis. This means collection of blood within the joint space. So this hemarthrosis may distract the joint surfaces causing a posterior open bite on the affected side or the same side with the deviation of the mandibular midline towards the opposite side. So this is characteristic of a contusion injury or where there is bleeding within the joint space without any definite fracture. The second diagram is that of a unilateral fracture with significant dislocation or displacement. This may result in contraction of the fragments under the action of pterigomacetic sling with ipsilateral premature posterior contact. ipsilateral means on the same side. So when there is action of pterigomacetic sling, it produces a premature posterior contact on the same side and the deviation of mandibular midline to the affected side. So there is premature contact and shift of midline towards the same side. The third diagram is that of bilateral fracture dislocation. Here the fracture condyles are dislocated medially in this case medially. This will produce a premature posterior contact on both the sides with no deviation. Here there is no shift in midline but there is premature contact on both the sides with anterior open bite. This is characteristic of bilateral condyler fractures with dislocation. The fourth figure shows bilateral dislocation without fracture. Here the condyles are not fracture but it is dislocated completely. It means the condyler heads are out of glenoid fossa. This is likely to produce an appearance of long face or prognathism. The patient is unable to occlude the posterior teeth. So there is almost complete inability to occlude any teeth and there is appearance of prognathism or pseudo prognathism. So these are the characteristic disturbances of occlusion after condyler injury. Moving on to the investigations associated with condyler injuries. Conditioned advances in the field of imaging technology have enabled accurate diagnosis and localization of condyler injuries. So you may use conventional radiographic techniques like orthopantamogram, reverse towns view or a transcranial view of TMJ to visualize the injured condyle. You may also use computed tomography and MRI or arthrography. MRI or magnetic resonance imaging is usually performed to study the soft tissues associated with the temporal mandibular joint and arthrography is mainly used to study the joint space. So these are the investigations associated with condyler injuries. The proper management of the fractured mandibular condyle is one of the most controversial topics in maxillofacial trauma. The commonly accepted goal of treatment is the re-establishment of the pre-operative function of the masticatory system. That means it is important to restore the masticatory function as it was before the injury. And this involves re-establishment of the pre-op relationship of the fracture segments, the occlusion and maxillofacial symmetry. So even if you perform a perfect radiographic alignment of the fracture segments, it is not adequate if you are unable to achieve a fully functioning and pain-free joint. These are the general principles associated with management of condyler fracture. Whichever technique you follow, whether you do it conservatively or surgically, these are the principle goals you need to achieve. Now the treatment is divided into two schools, conservative or non-surgical and surgical approaches. Moving on to the conservative management of condyler fractures. Conservative approaches have been practiced by a majority of surgeons and this technique is utilized for all kind of mandibular condyle fractures except those fractures which are an absolute indication for open re-election. Primary goal of conservative and functional treatment is to facilitate active jaw movement as early as possible and also to restore normal occlusion and neuromuscular pathways. The conservative management of condyler fractures can be as simple as observation and soft diet or it may include variable periods of immobilization followed by intense physiotherapy. But still close supervision is mandatory and at the sign of any occlusion instability, deviation with opening or increasing pain, both clinical and radiographic re-evaluation should be performed. Any of these findings like occlusion instability or pain may indicate the conversion of treatment from conservative to surgical. Immobilization Immobilization is one of the major components of conservative management of condyler fractures. The period of immobilization is controversial and must be long enough to allow initial union of the fracture segments but short enough to prevent the complications. What are the complications associated with long duration of immobilization? They include muscular atrophy, joint hypermobility and ankylosis. Currently the period of immobilization ranges from 7 to 21 days i.e. up to 3 weeks. This period may be increased or decreased based on concomitant factors such as the age of the patient, level of fracture, degree of displacement or presence of additional fractures. So this is all about conservative management of condyler fractures. The second approach to manage a fractured condyle is surgical or open reduction. Zyde and Kent have proposed a set of both absolute and relative indications for open reduction of the fractured manubular condyle. The absolute indications include displacement of the condyle into the middle cranial fossa, impossibility of obtaining adequate occlusion by closed techniques or conservative techniques, lateral extracapsular dislocation of the condyle, any foreign bodies within the TMJ capsule, mechanical obstruction that impedes the function of the TMJ and also open injuries like penetration, laceration or evulsion to the TMJ. All these conditions require immediate treatment and is an absolute indication. The relative indications include bilateral condyle fractures in an idensilus patient where you cannot fabricate a splint because of severe rich atrophy, unilateral or bilateral fractures where splinting is again not recommended because of any concomitant medical conditions or when physiotherapy is not possible, bilateral fractures associated with comminuted midfacial fractures and also bilateral fractures associated with other orthodontic problems. So these are the absolute and relative indications mentioned for opening a manubular condyle. But still you need to carefully evaluate the patient on an individual basis and then decide upon the treatment plan. Several surgical approaches to the condyle and the location of the fracture and the degree of displacement decides the selection of approach to access the joint. Subcondylar fractures may be easily accessed via submandu-bla or retro-mandu-bla incisions. But the danger of these techniques is the possible damage to the marginal mandu-bla nerve. If the fracture is in the intracapsular or high on the condylar neck then a pre-auricular or end-aural approach is used. It offers better access, more visibility and ease of manipulation. Some surgeons use intra-aural approach to reach the condyle. This approach has the advantage of visualizing the fracture reduction as well as the occlusion simultaneously. But the disadvantage of intra-aural technique is that there is limited access and also it is difficult to place certain fixation devices. Intradectomy again provides a good access and it is considerably aesthetic also because the scar is placed behind the ear fold. Hemi-coronal approach is used when the condylar fracture is associated with concomitant mid-face fractures or frontal bone fractures. In such cases, Hemi-coronal approach can be used which gives good access to the condyle. The vital structure at highest risk of damage during a pre-auricular approach to the condyle is the facial nerve. This diagram shows the relationship of facial nerve and its branches to the condyle and auditory canal. Here is the bifurcation of the main concoff facial nerve. It is at this point that the facial nerve divides into its five peripheral branches. So this bifurcation is approximately 1.5 to 2.8 cm away from the lowest concavity of external auditory canal. This is the external auditory canal and the bifurcation is 1.5 to 2.8 cm away from this position. The bifurcation is again 2.4 to 3.5 cm away from the post-glenoid tubercle. This is the posterior most tubercle at the glenoid fossa and the bifurcation is approximately 2.4 to 3.5 cm away. Here is the temporal branch of facial nerve which is again 2 cm away from the most anterior concavity of the canal. This is the anterior concavity of the external auditory canal and the temporal nerve or the temporal branch is 0.8 to 3.5 cm away from the anterior most concavity. So it is important to keep these measurements in mind to avoid any damage to the nerve while placing an incision or proceeding with dissection. Here is a brief explanation of the pre-auricular atroch. First the skin in front of the tragus of the ear is infiltrated with local anesthetic solution to ensure hemostasis. Then the incision is outlined at the junction of the facial skin and the helix of the ear. The incision is usually 3 to 4 cm in length and has two limbs, an upper curved limb and an inferior vertical limb anterior to the tragus. Incision is made through the skin and subcutaneous tissues towards the depth of temporalis fascia. It is here that you encounter the superficial temporal vessels and it is retracted anteriorly. This is exposure of the temporalis fascia. At this point you can palpate the zygomatic arch and the lateral pole of mandibular condyle. Here is the arch and here is the condyle. So at this point you can palpate it using finger. Then you make an oblique incision on the surface of temporalis fascia. You place an oblique incision which is parallel to the temporal branch of the facial nerve. The incision should be parallel so that it doesn't cut or it doesn't reset the temporal branch. So you place an oblique incision parallel to the temporal branch through the superficial layer of temporalis fascia. And this is all done above the arch. As you can see in the diagram, this incision and the dissection following incision is all performed above the level of zygomatic arch. You then insert a periosteal elevator beneath the superficial layer of temporalis fascia and the temporalis muscle and strip off the periosteum from the lateral aspect of the arch. You insert an elevator through this incision to reach the zygomatic arch and elevate the periosteum of the arch. The dissection is then carried out inferiorly to expose the capsule of the joint. As you can see in the diagram, as the dissection proceeds inferiorly, the capsule of the joint is visible, which is then incised and the fracture is exposed. So this is in general the principle and the procedure of pre-aricular approach to conduct. There are different modifications of pre-aricular incision. Pre-aricular incision is basically placing an incision within the skin crease in front of the tragus. As you can see in this diagram here, the dotted lines represent the classic pre-aricular incision. Several authors have given modifications to this incision by extending or altering it. For example, alkyth and brambley modification is the extension of pre-aricular incision anteriorly and superiorly. Few other modifications are inverted hockey stick incision by Blair, vertical angulated incision by Thoma and Dinkman incision. Here is the Popovich incision in which the pre-aricular incision is modified into a question mark shape. You have post-aricular incision. As you can see in the diagram here, the dotted violet lines represent post-aricular incision. This is placed behind the ear within the skin crease. You also have end oral incision. This incision is carried through the skin over the tragal cartilage. It is not placed right in front of the tragus but it is placed within the cartilage of the tragus. In this kind of incision, most of the vital structures are in the superficial plane and it gives good access to both the joint and the coronoid process. This is another approach to the condyle which is called the rightedectomy or facelift approach. This is an incision that provides the same exposure as the retro mandibular and pre-aricular approach. Basically, it is a combination of both the retro mandibular and pre-aricular approach. The advantage of this incision is that it is placed in a more cosmetically acceptable location. So, in this figure you can see all the incisions and all the approaches used to reach the condyle that is pre-aricular incision, the end oral incision, inverted hockey stick incision, post-aricular incision and retro mandibular incision. Here is the hemicoronal or bicaronal incision which is used to gain access to the condyle when it is associated with mid-face or frontal bone fractures. Here the incision is placed in this manner and the dissection is carried out through all the layers of scalp. After gaining a surgical access to the condyle, the fractured fragments are reduced in anatomical position and fixed using any of these methods, transocious wiring. This is used for sub-condyle fractures. Here the condyle is approached through sub-mandibular incision and holes are drilled in the fragmented segments. The wire is passed across the segments, it is twisted and tightened. In case of a high-condyle fracture, this is a high-condyle fracture where a pre-aricular incision will be better. Here the fragments are drilled obliquely from the lateral aspect of the fracture, that is you know a mandible has both the lateral and middle aspect. So while performing any procedure on the condyle or head, you take access from the external or the lateral aspect of the mandible. So you drill a hole obliquely here so that you don't injure maxillary artery or other blood vessels in the vicinity. Again transocious wiring is performed and the fragments secured in place. The next technique is the Kishner wire or K-wire technique in which a vertical passage is first drilled across the two fracture fragments and a K-wire is passed in through it. The wire is then secured using transocious wires. The third technique is the intra medullary screw which is placed through sub-mandibular incision. This is a rather inaccurate technique and not used commonly these days. In bone pin technique, two pins are inserted on either side of the fracture site and connected by a condyle or head and universal joint. This technique is also no longer in use and if at all practiced is very rare. Bone plating is the most popularly used fixation technique. Bone plates provide both stability and fridge decay. It also has added advantage of EC application. This is an example of sub-condyler fracture which is stabilized using a mini plate but whereas in case of multiple fracture it is difficult to perform this procedure within the surgical field. Therefore in such cases the ramus is osteotomized in this way. The ramus is osteotomized and the fractured fragments are plated outside the surgical field. That is the fragments are treated like autogenous bone grafts. It is treated totally outside. It is then plated to the main segment again using bone plates. So after fixation the drains are placed, the wound is closed and pressure dressing is applied. The postoperative management includes analgesics, anti-inflammatory, soft diet and intense physiotherapy. Moving on to the complications associated with condyle fractures. There are early and late complications. Complications that occur concurrent or with the treatment of condyle fractures include the following. Complications of tympanic plate, fracture of the glenoid fossa, with or without displacement of the condyler segment into the middle cranial fossa. Damage to the cranial nerves 5 and 7 that is the trigeminal and the facial nerves and vascular injuries. These are the early complications of condyle fractures. Late complications include malocclusion, growth disturbances, temporomandibular joint dysfunction and ankylosis in children. So with this we have completed the topic on condyle fractures as well as management of mandibular fractures. Thanks for watching.