Mt. Sinai Hospital Services, City Hospital Center, Elmhurst, New York.

Transcription

1 CONDYLAR FRACTURES ROGER G. GERRY, D.M.D., F.A.C.D. Mt. Sinai Hospital Services, City Hospital Center, Elmhurst, New York. IN a short presentation, it is impossible to cover definitively a subject so controversial as this. On this basis, lengthy case reports, statistical data and even the use of condylar X-rays, which are highly important diagnostically but reproduce poorly, will be omitted. In a Similar manner, areas in which there is essential agreement among most writers, i.e. incidence and causes, will be avoided, and an effort will be made to concentrate on aspects of the problem about which there are extensive differences of opinion. Detailed descriptions of standard surgical procedures will not be given. Diagnosis.--Any person having a history of recent facial trauma, who presents with tenderness or oedema of the condylar region, should be suspected of having a condylar fracture until proved otherwise. Patients having condylar fractures, or mandibular joint sprain, may also demonstrate limitation of mandibular motion, absence of condylar excursion, and deviation of the depressed mandible towards the injured side. Patients presenting with traumatically acquired open bites or disto-occlusion may be suspected of having bicondylar fractures. Haemorrhage from the external auditory canal is very rare as the tympanic plate is seldom fractured. Mandibular movement of patients suspected of having condylar fractures should be discouraged in order to avoid increasing the malposition of the condylar fragment as the result of the displacing action of the external pterygoid muscle. Until a diagnosis can be established, and definitive treatment started, the mandibles of such patients should be supported, temporarily, by a chin-strap bandage which does not exert any stress, in the posterior direction, on the mandible (Gerry, I959). Every patient suspected of having a condylar fracture should have the benefit of four X-rays, as these may be the only means of establishing a diagnosis. These are the postero-anterior and Towne's views of the skull and lateral oblique views of the entire involved ramus and of the involved mandibular joint taken with the teeth in their usual occlusal relationship. The postero-anterior and Towne's views show medial, lateral or inferior displacement of any part of the proximal fragment. The former view produces less distortion of the bony structures, but superimposition of the malar and mastoid process may obscure some of the pertinent findings. The Towne's view avoids superimposition but elongates the condyle and its neck. This elongation may be of advantage by distorting, and making more obvious, a linear fracture not otherwise demonstrable. The lateral oblique views demonstrate anterior and inferior displacement of the proximal fragment. The absence of a condyle from its glenoid fossa is strongly suggestive of fracture-dislocation and, in these instances, use of lateral tomographic views may be of great value in demonstrating the degree of condylar displacement. Classification.--All condylar fractures may be classified into one of three categories based on the position of the fractured condyle. These are I. Undisplaced II4

2 CONDYLAR FRACTURES II 5 fractures (Fig. I); 2. Displaced fractures which are not dislocated (Figs, z, 3, 4); and 3. Fracture-dislocations (Figs. 5, 6, 7). There is a tendency to add, as a fourth category, the group of intracapsular fractures (Figs. 4 and 7), but these, therapeutically, may be fitted into one of the previously mentioned categories. Condylar fractures in children present the additional problem of possible growth centre injury, and this possibility requires special consideration, but the fractures themselves may be fitted into one of the categories listed above. TREATMENT Undisplaced condylar fractures.--these are linear fractures in which the proximal fragment retains its usual anatomic relationship with the distal fragment. Since concurrent fracture of the tympanic plate or the glenoid fossa (Markowitz & Gerry, 1949, 195o) are virtually unknown it must be assumed that these, as well as the other types of condylar fracture, are caused by the spastic contraction of the external pterygoid muscle at the moment of impact while the remainder of the mandible moves posteriorly or laterally from the force of the blow, or remains fixed in position by the occlusion and the spastic contraction of the elevator muscles. As the result of this fracturing force, many condylar fractures occur just inferior to the insertion of the external pterygoid muscle. Undisplaced condylar fractures (Fig. I) should be treated by mandibular immobilization for a period of about four weeks, or even less in children, as firm pre-osseous union should occur in this time. In the case of the edentulous patient, it is a simple matter to accomplish immobilization by a combination of circumferential wiring of the mandibular denture and a double strand wire of placed, subperiosteally, across the palate, with the ends leading out, through drill holes, above the periphery of the maxillary denture in the lateral incisor regions. Rigid intermaxillary fixation may then be accomplished by twisting the free ends of the trans-palatal wire beneath the symphyseal circumferential wire, or wires. It is particularly important that the mandible be immobilized in patients exhibiting condylar fractures, especially bilaterally, who are bed-ridden because of other injuries. In such 'cases, the distal fragment, including the mandibular dentition, will tend to drift gradually into a disto-occlusal relationship. Even if this displacement has taken place, an effort should be made to reduce the distal fragment, as, if adequate traction is employed, it is possible to correct this displacement even in condylar fractures which are four or five weeks old. Many writers feel (Fry et al,, 1943) and this is Controversy I, short periods of mandibular immobilization should be used so that pre-osseous union will not eventuate, and that the injury will repair by pseudo-arthrosis at the fracture line. It is their "feeling, on this basis, that prolonged immobilization is not only unnecessary but actually harmful. This thesis appears to be untenable when examined. First of all, pseudo-arthrosis provides a "hinge" joint which is unsatisfactory in this area for reasons which will be established below. In addition, most writers agree that surgically created pseudoarthrosis, in the treatment of condylar ankylosis, usually ossifies unless the created defect is very wide. It is therefore, invalid to assume if surgical pseudo-arthrosis ossifies that traumatic pseudo-arthrosis will not. Most condylar fractures treated by early mobilization

3 116 BRITISH JOURNAL OF ORAL SURGERY repair normally in spite of the short period of fixation, although post-fracture malocclusion may be harder to control. In fact, Rakower et al. (I96I) report satisfactory healing of a condylar fracture in a child whose mandible was immobilized only nine days. On this basis, the re-establishment of condylar excursion is desired, even if unwittingly, by the advocates of early mobilization. If this assumption is correct, immobilization should be maintained for a sufficiently long period to assure that ultimate osseous union will eventuate and the patient's dentition will remain in its usual occlusal relationship. Displaced condylar fractures which are not dislocated: (Figs. 2, 3, 4)- In this type of fracture, the proximal fragment is displaced, but the articular surface of the condyle remains within the glenoid fossa and has not herniated through the joint capsule. Two characteristic types of displacement occur. In one the articular surface is displaced anteriorly and may come to lie beneath the articular tubercle (Fig. 2). In the other, the inferior end of the proximal fragment is displaced laterally, and may over-ride the lateral aspect of the distal fragment (Fig. 3). In the latter type of fracture, the joint space may be increased even though the condyle remains in a relatively vertical position. The latter type of fracture usuauy is characterized by a fracture line which extends obliquely downward to form a sharp point with the lateral surface of the condylar neck. This point may enter the substance of the masseter muscle and produce pain and, on this basis, several writers (Giammusso & Johnson, 1959), (Malkin et al., I964) have advocated open reduction of this fracture, through the sub-mandibular approach of Risdon (1934) because of the inferiorly extending fracture line, and fixation of the condylar fragment with a stainless steel wire or with a "V"-shaped tantalum plate. Actually, it may be assumed, in both types of displacement described above, that the articular head of the condyle remains, more or less, in the glenoid fossa; that the joint capsule has not been herniated; that the joint space has not been sufficiently increased to permit significant upward displacement of the involved side of the mandible; and that the contractile length of the external pterygoid muscle has been, for the most part, preserved. Since all the requisite components of good condylar function remain, in only moderately altered relationships, if intermaxillary fixation in the patient's usual occlusal relationship is employed and if proper rehabilitation practices are utilized, it may be assumed that the patient may expect to recover the full range of mandibular motion and function even though the condyle has healed in a moderately displaced position. In fact, it may be anticipated further that, after healing, condylar re-moulding, stimulated by the intact capsule, will take place gradually, and the condyle will appear, ultimately, as though it had never been fractured. In treating this type of condylar fracture, it may be wise to increase the period of immobilization to four weeks, plus an additional day for each millimetre of displacement. Many writers (Thoma, K.H., I956), (Sleeper, E. L., 1952 ) have recommended (Controversy 2) that all fractures ill this group should have the benefit of open reduction, using the pre-auricular approach when the condyle is displaced anteriorly and the submandibular when there is lateral over-riding. However, since completely normal joint function may be expected, after rehabilitation, if the mandible is immobilized properly, there is no basis for open reduction unless it is impossible to reduce the mandible into the patient's usual occlusal relationship. It is almost needless to add that this is a circumstance of the utmost rarity.

4 CONDYLAR FRACTURES 117 ~\--. ' ~ I FIG. I FIG. 2 FIG. Undisplaced condylar fracture. Intermaxillary immobilization is the only treatment indicated. FIG. 2 Anteriorly displaced condylar fracture which is not dislocated. The condyle is in contact with the articular tubercle and the capsule is intact. The patient should regain normal function following intermaxillary immobilization~ but may require rehabilitation after the fracture has healed. I FIG. 3 FIG. 4 FIG. 3 Medially displaced condylar fracture which is not dislocated. The condylar articular surface remains in the glenoid fossa and the capsule is intact. The patient should regain normal function following intermaxillary immobilization, but may require rehabilitation after the fracture has healed. FIG. 4 "Intra-capsular" condylar fracture. The lateral aspect of the condyle remains in anatomic position. The medial aspect, including the external pterygoid muscle insertion, is displaced anteriorly. The capsule is intact. The patient should regain normal function following immobilization, but may require rehabilitation after the fracture has healed.

5 II8 BRITISH journal OF ORAL SURGERY Occasionally, some of the fractures in this group will be intra-capsular (Figs. 4 and 7). When these occur, the fracture line usually follows the lateral margin of the insertion of the external pterygoid muscle. The triangular section of condylar head, including the medial 2/3 or more of the articular surface, will be displaced medially or anteriorly leaving the lateral aspect of the condylar head in continuity with the rest of the mandible. In such cases it would be surgically unfeasible to attempt open reduction without the very great risk of destroying the attached lateral portion of the condylar head. Fractures of this type are unusual, but when the mandible is immobilized as described above, pre-osseous repair will occur by the time of mobilization. If a patient in this category is observed for an adequate period, the space between the fixed and displaced condylar fragments will fill with callus and, as normal condylar function returns, condylar re-moulding will occur and a normal condylar contour develop. Condylar fracture-dislocations: (Figs. 5, 6, 7).--In this type of fracture the proximal fragment is displaced outside the glenoid fossa and may be assumed to have herniated through the capsule. The articular surface may be displaced in an anterior (Fig. 5), antero-medial, or medial (Fig. 6) direction and may be distracted 90 degrees, or more, from its anatomic position. A demonstrable space may separate the proximal and distal fragments. Intracapsular fracture-dislocations are seen, occasionally. In these a triangular fragment, which includes the external pterygoid insertion, is displaced medially through the joint capsule. Obviously, the fracture-dislocation presents greater problems in management than do the other types of condylar fracture. The empty glenoid fossa ultimately fills with scar tissue which inhibits condylar excursion which, after cicatricial contraction develops, tends to elevate the distal fragment and may produce acquired malocclusion. The contractile length of the external pterygoid muscle is shortened, dramatically in the case of anterior and antero-medial fracture-dislocations, with resultant loss of condylar excursive potential which, with the articular adhesions already described, may rule out the probability of a gliding condyle. Some writers, as Thoma (1956) and Sleeper (I952) feel that condylar fracture-dislocation must be treated by open reduction if efficient mandibular joint function is to recur. Others, as Fickling (1964), Blevins and Gores (1961) and MacLennan (I952 and 1956) never advocate open reduction and suggest that, as the result of normal joint function, the malunited condyle ultimately will re-mould to a normal configuration. The latter observation assuredly is valid, even with the partial loss of re-moulding potential as the result of capsule herniation. The latter opinion, also, is supported by several excellent series (MacLennan, 1952), (Blevins & Gores, I96I ) of reported cases. In addition, improved methods of rehabilitation have made it possible to achieve normal joint function in badly displaced fractures and in many fracture-dislocations (Gerry, I959). However, what becomes of the patient with a fracture-dislocation who does not recover normal joint function? Obviously, he does not benefit from the effect of condylar re-moulding, and may have some very real long-range problems as the result. If there was some easy way of deciding, when the patient presents, whether or not he ultimately will regain normal condylar function, the problem would be an easy one. Unfortunately, the answer is not, necessarily, the open reduction of all doubtful cases, as many operated fracture-dislocated condyles do not unite and normal joint function does not follow. Unhappily, these fractures usually are not reported in the

6 CONDYLAR FRACTURES 119 literature. During recent years a few writers (Georgiade et al., 1956) have utilized the surgical technique of exposure of the fractured end of the proximal fragment, through a pre-auricular incision, and the insertion of a skeletal fixation pin near the fracture line. This is used as a "handle" with which to reduce the fracturedislocation, but because of the depth of the small surgical field, it may be necessary 7"' FIG. 5 Anterior fracture-dislocation, in which the joint capsule has been herniated. In this case, there is contact between the fractured surfaces and the condyle is in contact with the articular tubercle. This patient should regain normal function following intermaxillary immobilization, but will require rehabilitation after the fracture has healed Lord (1915) describes the condyle of a prehistoric, excavated skull, in which the findings may be those of healed, functional anterior fracture-dislocation. If the condylar angulation was much greater, or if the fragments were separated, open reduction might be indicated. FIG. 6 Medial fracture-dislocation, in which the joint capsule has been herniated. This patient should regain normal function following intermaxillary immobilization, although rehabilitation will be required after the fracture has healed. If the condylar angulation was much greater, or if the fragments were separated, open reduction might be indicated. FI~. 7 "Intracapsular" fracture-dislocation. The lateral aspect of the condyle remains intact, but the medial fragment, including the external pterygoid muscle insertion, has been displaced medially. The capsule has been herniated, but if the displacement was not so great, the capsule would remain intact and the fracture would be considered to be displaced, but not dislocated. This patient should regain normal function following intermaxillary immobilization, although rehabilitation may be required after the fracture has healed. to re-set the pin three or four times. These extra pin-holes stimulate callus formation. In this procedure the capsule is entered rarely and the articular surface is never exposed. The pin is left in position and, after closure of the incision, is attached by the usual linkage to the mandibular angle. If post-operative X-rays show less than satisfactory position, further adjustment is feasible. The pin is removed after about two weeks, but the usual period of intermaxillary immobilization is completed. This method is less traumatic than conventional

7 120 BRITISH journal OF ORAL SURGERY open reduction and is less likely to impair the condylar blood supply through the external pterygoid muscle. As the result of these advantages, union is more likely to eventuate. How, then, is it possible to prognosticate which fracture-dislocations will regain normal condylar function without surgical intervention, and which will benefit from open reduction? This is still, largely, a matter for the judgment of the individual oral surgeon. It is safe to state, however, that bicondylar fracturedislocations do not require open reduction, as the deformity is symmetrical, and with a little assistance and guidance, the patient will learn to achieve bicondylar excursion. If he does this, the mandible will not be displaced posteriorly and open bite will not ensue. Similarly, dislocated intra-capsular fractures (Fig. 7) do not require open reduction, essentially because a part of the condyle remains, uninjured, and to reduce the dislocated fragment would involve destruction of the undisplaced portion. While there is no doubt that a substantial "gray" area remains, it is likely that those anterior fracture-dislocations which are separated from the distal fragment are more likely to recover normal function following competent open reduction. Condylar fractures in children.--this problem is one in which there is a high degree of harmony, as most writers (MacLennan, 1952 and I956), (Graham & Peltier, 196o), (Rakower et al., 1961), are of the opinion that condylar fractures in children should never be treated by open reduction. All writers justify this attitude because of the possibility of inducing subcondylar growth centre injury as the result of surgery. Rakower et al. (1961) have reported a series of three condylar fractures in children, including a medial fracture-dislocation, which were treated by immobilization only. All regained normal condylar function and all demonstrated satisfactory degrees of condylar remoulding. On the other side of the coin, I have seen four patients who had suffered condylar fractures as adolescents, and who demonstrated characteristic growth deformities as adults. It is worthy of comment that none of the four had normal condylar excursion, or was able to masticate with the contralateral teeth. This finding supports strongly the thesis that condylar function has more to do with condylar development than does the subcondylar growth centre. The validity of this observation is supported by the findings in two other children, one only four years old, who had intracapsular condylar fractures, which, characteristicauy, extend across the articular surface and involve the subcondylar growth centre. Both regained normal condylar function; eventually accomplished condylar remoulding to normal contour; and had no mandibular growth deformities whatever. The foregoing summary leaves unresolved the problem of the management of the child who has suffered a severe condylar fracture-dislocation who is not likely to develop normal condylar function following treatment by immobilization alone. Fortunately, condylar fractures are relatively rare in children. MacLennan (1952) reports only 2.78 per cent. of his series in children under IO years of age, and severe fracture-dislocation is almost never seen. In 1957, I performed an open reduction, using the inserted pin method outlined above, to reduce a condylar fracture-dislocation in an eleven-yearold girl whose condyle was displaced about IiO degrees medially. Following mandibular mobilization, the patient rapidly recovered normal condylar function, and subsequently has had normal, symmetrical mandibular growth.

8 CONDYLAR FRACTURES 121 REHABILITATION OF CONDYLAR FRACTURES A patient who has had a condylar fracture cannot be considered to be cured until he is able to masticate easily with the contralateral side of the dentition, which implies the recovery of condylar excursion. To this may be added the requirement of normal, undeviating mandibular depression, but if adequate condylar excursion exists, deviation becomes a matter of impaired proprioception, which is not of consequence so long as the patient practises contralateral mastication. Numerous writers (Controversy 3) are willing to accept a hinge-type mandibular joint, with accompanying inability to masticate contralaterally and uncontrollable ipsilateral deviation during mandibular depression, as being a completely satisfactory result. This premise cannot be accepted. Sometimes a better result cannot be obtained, but this does not justify its establishment as the standard of acceptability. Patients with unilateral hinge-type joints rapidly develop over-function of the contralateral joint with subsequent hypermotility, disc derangement, and ultimately chronic dislocation. Since these findings may not present for a year or more after fracture, this condition is called the "condylar post-fracture syndrome". Because the uninjured condyle is most often involved, the syndrome may not be associated with the original fracture and the oral surgeon who treated this may be unaware of the delayed sequela. However, those who have had long experience with mandibular joint problems, in all categories, are cognizant of the importance of the condylar post-fracture syndrome. In addition to hypermotility of the uninjured condyle, the fractured condyle sometimes shortens, as the result of displacement and scar-contracture, becomes painful, and may produce premature contact of the ipsilateral teeth and even deviation of the dentition toward the deformed condyle. All these sequelae contribute toward acquired malocclusion and precocious loss of the dental tissues. Actually, the rehabilitation of condylar fracture patients is quite simple provided two general practices are followed. I. The patient should not be discharged from treatment until he has acquired a gliding condyle and can masticate with the contralateral teeth and; 2. The Patient should have a thorough understanding of his problem as well as his own role in correcting it. This can best be done by demonstrating a hinge joint and a gliding joint on a skull, and by explaining the patient's own deformity to him in front of a looking glass. Most patients, following recovery from undisplaced condylar fractures, will require little or no rehabilitation apart from dental equilibration subsequent to the return of condylar excursion. Patients who have had displaced fractures will require a bit more supervision, but, ordinarily, the knowledge of what they are aiming for is adequate to stimulate the reacquisition of condylar excursion. Patients who do not recover condylar excursion readily, and this group includes most fracture-dislocation patients, should be taught to stand in front of a looking-glass and practise contralateral mandibular excursions by applying the antero-lateral margin of the tongue against the lingual surface of the mandible. If needed, especially at the beginning, hand pressure in the same direction, against the opposite side of the mandible, may be used as a supplement. This exercise should be practised for a few minutes at least several times daily but, preferably during every waking hour. By following these exercises, cicatricial adhesions will be stretched and external pterygoid tone and capacity will be improved. Since the development of these exercises, the use of flanges has been discontinued. In addition to the foregoing, patients

9 I22 BRITISH JOURNAL OF ORAL SURGERY should be required to masticate a regular diet with the contralateral side of the dentition. Once lateral excursion starts, it is amazing how rapidly it will develop, and how acquired malocclusion, and even premature contacts, will resolve. When the initial point of maximum improvement has been attained, equilibration of the dentition should be accomplished. However, the patient should be advised to continue to masticate on the side of his dentition contralaterally to the fractured condyle until his mandibular excursions become bilaterally symmetrical. Patients with year old, or older, malunited condylar fractures who have been referred for arthroplasty, have been placed on this routine and have developed relatively normal ranges of mandibular motion as well as resolution of pain within a few days and without the need for surgical interference. REFERENCES BLEVINS, C. ~v ~ GORES, R. (r96t). ft. oral Surg. Anesth, I9, 392. FICKLIN~, B. W. (I964). ft. oral Surg. Anesth. z2, I42. FRY, W. K., SHEPHERD, P. R., McCLoED, A. C. & PARFIT, G. J. (r943). The Dental Treatment of Maxillo-Facial Injuries, p. IO4. Oxford: Blackwell. GEORGIADE~ ~]'.~ PICKRELL, K., DOUGLAS~ W. ~9' ALTANY, F. (I956). Plast. reconstr. Surg. I8, 377. GERRY, R. G. (I959). In SCX~WARrZ, L. Disorders of The Temperomandibular ffoint, P Philadelphia: Saunders. GIAMMUSSO, A. P. C,~ JOHNSON, W. B. (I959). ft. oral Surg. Anesth. x7, 67. GRAHAM, G. G. & PELrIER, J. R. (I96O). ft. oral Surg. Anesth. I8, 416. LORD, F. P. (I915). Anat. Rec. 9, 46I. MAcL~NNAN, W. D. (I952). Brit. ft. plast. Surg. 5, I22. MAcLENr~AN, W. D. (I956). Brit. ft. plast. SurF,. 9~ I25. MALKIN, M., KRESBERG, H. ~' MANDEL, L. (I964). Oral Surg. x7, I52. MARKOWlTZ, H. A. & GERRY, R. G. (I949). Oral Surg. z, I3o9. MARKOWITZ, H. A. & GERRY, R. G. (r95o). Oral Surg. 3, 75. RAKOWER, W.~ PROTZELL, A. & ROSENCRANS, M. (I96I). ft. oral Surg. Anesth. xg~ 5r7 RISDON, F. (I934). Amer. dent. Ass. zx, I933. SLEEI'F.R~ E. L. (I95z). Oral Surg. 5, 4. THOMA, K. H. (I956). ft. oral Surg. x4, 93.