Oral Maxillofacial Surg Clin N Am 19 (2007) 223–234 Condylar Resorption Maria E. Papadaki, DMD, MD, Fardad Tayebaty, Leonard B. Kaban, DMD, MD, Maria J. Troulis, DDS, MSc* Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Harvard School of Dental Medicine, 55 Fruit Street, Warren Bldg. 1201, Boston, MA 02114, USA Various pathologic conditions, such as osteo- (destructive) nature of the condition was docu- arthritis, rheumatoid arthritis, condylar hyperpla- mented [3]. sia, and idiopathic condylar resorption (ICR), affect the temporomandibular joints (TMJ). As a result, the size and morphology of the condyles Etiologic theories may be altered. Both men and women are General considerations affected; however, more so than the other condi- tions, ICR is almost exclusively found in women The exact cause and pathogenesis of condylar [1]. In this article, the diagnosis and management resorption remain unclear. It has been associated of ICR are discussed. with rheumatoid arthritis, TMJ internal derange- ICR is a poorly defined acquired disorder that ment, trauma, steroid use, systematic lupus eryth- is characterized by progressive decrease in condy- ematosus, scleroderma, other vascular collagen lar mass and alteration of condylar shape. It is diseases, orthodontic treatment, and orthognathic almost always bilateral and seems to have a high surgery (secondary condylar resorption) [4,5].In predilection for women in the age range of 15 to most cases, however, there is no identifiable pre- 35 years [1]. Other terms for this condition include cipitating event; hence, the term ‘‘idiopathic con- condylysis, osteoarthrosis, dysfunctional remodel- dylar resorption.’’ De Bont and Stegenga [6] ing, avascular necrosis, osteonecrosis, and condy- subdivided condylar resorption into primary (idi- lar atrophy. Resorption may progress to include opathic) and secondary, depending on the pres- the entire condyle, leaving only a stump at the in- ence of predisposing factors [7]. ferior aspect of the sigmoid notch. The mandibu- Two theories have been described with regard lar ramus below the sigmoid notch is spared. to the pathogenesis of condylar resorption. Arnett The resorptive process may become quiescent and colleagues [8] correlated it with increased, after 1 to 5 years but also can be reactivated; hence, abnormal joint loading and subsequent pressure the distinction between active and inactive condy- resorption, as might occur after orthodontics, or- lar resorption. After age 40, it is rare for patients to thognathic surgery, occlusal therapy, internal de- experience further resorption. rangement, parafunction, trauma, and unstable Condylar resorption was first reported by occlusion [9]. Chuong and colleagues [10,11] pos- Burke in 1961 [2]. He described it as an acquired tulated that the mechanism of condylar resorption condylar hypoplasia. By 1977, condylar resorp- was similar to that of avascular necrosis of the tion was distinguished from congenital condylar femoral head. Intraluminal or extraluminal oblit- aplasia or hypoplasia, and the progressive lytic eration of small vessels, damage to the arterial or venous walls, and increased intraosseous pres- sure from enlargement of intramedullary fat cells or osteocytes are factors that contribute to the de- * Corresponding author. velopment of avascular necrosis of the femoral E-mail address: [email protected] head [12]. Theoretically these conditions could oc- (M.J. Troulis). cur in the mandibular condyle. In 1989, Schellhas 1042-3699/07/$ - see front matter Ó 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.coms.2007.01.002 oralmaxsurgery.theclinics.com 224 PAPADAKI et al and colleagues [13] also reported MRI findings of Orthognathic surgery and condylar resorption unilateral or bilateral avascular necrosis of the Most of the literature on condylar resorption condyle in five patients who had undergone or- discusses its relationship to orthognathic surgery. thognathic surgery, including sagittal split osteot- In 1978, Phillips and Bell [23] first reported bilat- omies, followed by intermaxillary fixation. eral atrophy of the mandibular condyles after sag- Condylar resorption also has been considered ittal split osteotomy for mandibular advancement. to be the result of loss of the normal remodeling Although a definite cause could not be estab- capacity of the condyle caused by factors such as lished, they hypothesized that a biomechanical age, systemic illness, and hormones [8,9]. Wolford phenomenon based on increased muscle tension and Cardenas [14] believe that the mediators to was the most likely causative mechanism. By promote condylar resorption exist in the bilami- 1991, the role of condylar resorption in postoper- nar zone of the meniscus. In a series of 15 patients ative relapse and instability of occlusal and skele- with ICR, they found hypertrophy and prolifera- tal results was elucidated [18]. tion of bilaminar and synovial tissues around The incidence of condylar resorption after the head of the condyle. They hypothesized that orthognathic surgery is reported to range from exposure of the condyles to mediators in these tis- 1% to 31%, depending on various nonsurgical sues creates the resorptive phenomenon [15]. The and surgical factors [4,17,24–27]. The first radio- experience of our group does not support this hy- logic signs of resorption usually present 6 or pothesis. At the time of operation, we have found more months postoperatively [17]. Mandibular no abnormalities in the synovial tissues. Condy- advancement, maxillary impaction, mandibular lectomy and reconstruction with a costochondral autorotation, and bimaxillary osteotomies can in- graft (CCG) result in recreation and remodeling duce condylar resorption. of the condyle, and there is no further resorption Preoperative, nonsurgical, patient-related risk of the ‘‘neocondyle’’ with time, despite contact factors include antecedent TMJ dysfunction, con- with the synovial tissue. dyles with a posterior inclination, small, thin Idiopathic and secondary condylar resorption condyles, and a high mandibular plane angle affect men, but they are more frequently seen in with a low posterior-to-anterior facial height ratio women, with a 9:1 ratio [15–17]. The female pre- [4,7,8,17–19,25]. Patients who have open bite are ponderance may be attributed to the modulation more prone to condylar resorption compared of the bone response by estrogen and prolactin with patients who have deep bite deformities [17]. [8,17–19]. Estrogen receptors have been found in Surgical risk factors that contribute to post- the temporomandibular disk of women [20] and operative condylar resorption are controversial in the condyle and disc of female animals [21,22]. [4,13,17–19,28]. Bimaxillary osteotomies per- In a study of the human TMJ, Abubaker and formed for the correction of mandibular retrogna- colleagues [20] reported that estrogen and proges- thia with open bite present the highest frequency terone receptors were found five times more of condylar resorption. Kerstens and colleagues often in women with symptoms of TMJ internal [4] reported on 12 of 206 patients with high-angle derangement than in asymptomatic women. Seven mandibular retrognathia and open bite who devel- TMJ disc specimens obtained from women with oped condylar resorption after bimaxillary surgi- TMJ symptoms were analyzed for the presence cal treatment. In 1994, De Clercq and colleagues of these receptors. These specimens were [26] found 31% incidence of condylar resorption compared with another group of 15 TMJ discs of more than 2 mm in female patients with high- removed from men and women with no TMJ angle mandibular deficiency who underwent symptoms who were undergoing skull base bimaxillary osteotomies (9/29 patients). No corre- surgery and who had extirpation of the TMJ lation between resorption and age, the amount of for access to the skull base. Detection of retrognathism, or the presence of preoperative hormone receptors was performed with immuno- TMJ dysfunction was found. Hoppenreijs and histochemistry. It was concluded that the TMJ colleagues [17] reported progressive condylar re- disc is potentially a female sex hormone target sorption after bimaxillary osteotomies in 27 of tissue in some patients and that women may 117 patients who had mandibular hypoplasia have different responses to estrogen levels, based and open bite. on the target receptors within the TMJ. More The incidence of condylar resorption after studies should be performed to determine the Le Fort I osteotomy with maxillary posterior role of hormones in ICR. CONDYLAR RESORPTION 225 impaction only and autorotation of the mandi- postoperatively was highly predictive of condylar ble was found to be 9% to 12.5% [17,24].In changes occurring in the ensuing months. Of these cases, it was hypothesized that biome- note is that both of these studies lack information chanical loading of the condyles caused by au- regarding the presence or absence of active resorp- torotation of the mandible was a significant tion before the operation. contributing factor. With regard to the magnitude of mandibular Orthodontics and condylar resorption advancement, analysis of 18 orthognathic surgery Orthodontic treatment alone can cause condy- patients by Huang and colleagues [1] showed that lar resorption. Kato and colleagues [30] treated relapse occurred in patients having bimaxillary a 12-year-old girl who had bilateral impacted surgery with mandibular advancements more than maxillary canines and degenerative disease