Idiopathic Condylar Resorption: Reality or Myth?

Idiopathic condylar resorption (ICR) has been discussed extensively^1-8 since Burke⁹ introduced the term in 1961. In 2017, Young⁶ described ICR as “a condition with no known cause, which manifests as progressive malocclusion, esthetic changes, and often pain” (Figs. 1–4). The premise that ICR doesn’t have a known cause should be re-evaluated, however, given the insights that three-dimensional imaging with MRI and CBCT have provided over the past 40 years. 

4 decades of research and review

In 1985, before MRI imaging was available, Katzberg¹⁰ wrote:

“Significant injury to the soft tissues of the [temporomandibular joint/TMJ] may be the result of trauma. The high percentage of young patients with internal derangements of the TMJ in this series may be the result of poor recognition of this problem in the pediatric population, as well as the reluctance of the referring clinician to perform an invasive procedure such as arthrography. The usefulness of CT in such patients may allay some of these fears. 

Further awareness of internal derangements in pediatric patients should permit greater recognition of their etiology, as well as of the importance of initiating treatment as soon as possible, not only to minimize the development of osseous disease in young adults but also to prevent facial growth deformities.”

Katzberg’s recognition of the connection of internal derangements and facial growth deformities — another way to describe ICR — is one of the earliest references in peer-reviewed literature. 

In 1989, Schellas¹¹ wrote in a landmark article: 

“Magnetic resonance imaging has enhanced our ability to diagnose TMJ derangements. Recent clinical MRI investigations of more diverse patient populations demonstrate a causal relationship between TMJ derangement and degeneration and secondary facial skeleton remodeling or disturbed growth in those patients studied. Patients have been observed longitudinally to develop retrognathia, unstable occlusion disturbances, and mandibular asymmetry after the development of proven TMJ derangement and osseous degeneration.

The actual incidence of TMJ derangement in random retrognathic populations is yet to be investigated. This study represents the first large series of pediatric patients where MR imaging was used to study suspected TMJ derangement(s). In the growing facial skeleton, we propose that internal derangement of the TMJ(s) disk(s) either retards or arrests condylar growth, which results in decreased vertical dimension in the proximal mandibular segment(s) with ultimately mandibular deficiency or asymmetry.”

In 1997, Nebbe wrote:

“The findings of the current study tend to support the argument that internal derangement may be associated with altered craniofacial morphology in an adolescent sample. This pilot study shows reductions in total posterior facial height development and ramus height and a compensatory adaptation in the maxillary dentoalveolar region, with reduced vertical development of the maxillary first molar region.¹²”

Animal research on TMJ’​s effect on the mandible, midface, and cranial base

In a 1999 study by Legrell,¹³ researchers created a disk displacement in the right TMJ of seven 3-month-old rabbits but kept the posterior disk attachment, while seven rabbits underwent surgical opening of the TMJ without disk intervention and seven additional animals served as references. After three months, the animals were examined, and it was concluded that TMJ disk displacement in a growing animal can induce reduction of mandibular height and length before a stage where visible osteoarthritic changes develop. It implies a primary adverse effect on condyle growth. 

The effect that internal derangement of the TMJ might have on the asymmetric development of the cranial base was unknown, so Qadan’s 1999 study, also on rabbits,¹⁴ investigated the consequences of unilateral TMJ disc displacement on the midface and cranial base. Thirteen 10-week-old rabbits — eight controls and five with surgically created unilateral disc displacement — were subjects in this study. 

After 22 weeks, frontal, occlusal, and lateral oblique radiographs were made of the rabbit skulls: 

• Occlusal radiographs demonstrated that the glenoid fossa on the experimental side was located more anteriorly. 


• Oblique radiographs revealed the root of the zygomatic arch on the experimental side to be more inferior. 


• Frontal radiographs showed the anterior aspect of the fossa on the experimental side was seen to be more inferior. 

Qadan’s study points to an alteration of the cranial articular fossa; thus, it may be concluded that disc displacement is capable of producing asymmetry in both the developing mandible and the cranial base. 

Research in the MRI era, on human subjects

In a 2007 landmark study,¹⁵ Flores-Mir stated:

“The objective of this retrospective cohort study was to assess the association of temporomandibular joint (TMJ) disc status and craniofacial growth. Seventy-nine subjects (52 female, 27 male) with and without TMJ disc abnormalities were followed for a mean time of 3 years, 8 months. Of this sample, 40 subjects (21 female, 19 male) received orthodontic treatment. Disc displacement and disc length measurements from magnetic resonance imaging of the jaw joints were used to evaluate TMJ disc status. Horizontal and vertical growth changes were obtained from cephalometric radiographs. A stepwise multiple linear regression analysis was used to evaluate the influence of TMJ disc status and orthodontic treatment on the displacement vectors between initial records (T1) and final records (T2) for each cephalometric point. 

Less horizontal and vertical growth was found in specific regions of the maxilla and the mandible in subjects with TMJ disc abnormalities. TMJ disc abnormality was associated with reduced forward growth of the maxillary and mandibular bodies. TMJ disc abnormality was associated with reduced downward growth of the mandibular ramus.”

In 2019, Lei¹⁶ authored a study that used CBCT to evaluate the occurrence of degenerative TMJ changes in adolescents and young adults with recent onset disc displacement without reduction (DDw/oR). 

This study acquired the CBCT and clinical data of 300 patients — 254 females and 46 males, with a mean age of 20.93 ± 4.77 years — who’d been diagnosed with unilateral DDw/oR within the past 12 months, based on the research diagnostic criteria for temporomandibular disorders. CBCT images of symptomatic and contralateral asymptomatic TMJs were independently evaluated and scored by two radiologists.

• Condylar OA changes were present in 59.3% of the joints with DDw/oR. Early-stage OA changes (loss of continuity of articular cortex and/or surface destruction) constituted most of the alterations. 


• Prevalence of early-stage OA increased from 24% to about 60% one month after TMJ closed-lock occurred. Logistic regression analysis showed the risk of developing early-stage OA changes was 5.33 times higher one month after onset of DDw/oR. 


• A high prevalence of degenerative TMJ changes was observed with recent-onset DDw/oR in adolescents and young adults. Early diagnosis and intervention of DDw/oR is therefore prudent.

Condylar resorption isn’t “idiopathic” anymore 

Given the clear connection between disk displacement in growing patients and the lack of condylar growth and development, our views on ICR should be reevaluated. Idiopathic implies that the cause of the problem is unknown, but in this case, it’s clear that if the disk is not covering the condyle in the growing patient, there’s an increased risk the condyle won’t grow to its full genetic potential.

A strong argument can be made that the articular disk in the TM joint is the forgotten tissue in our profession. Alomar¹⁷ described the articular disk as the most important anatomic structure of the TMJ. 

While the disk is usually discussed in terms of whether the TM joint hurts or locks, the more important role of the disk relates to mandibular and maxillary growth. The Guidelines for Assessment, Diagnosis and Management published by the American Academy of Orofacial Pain¹⁸ state that “MRI represents the current gold standard of diagnostic imaging for soft tissues,” which includes the TM joint disk. 

If we don’t obtain MR imaging in the growing Class II patient, we assume there’s an “idiopathic” issue rather than a growth defect from a structural alteration in the TM joints. When we obtain MR imaging in the growing Class II patient, we’re better able to understand the problem and to offer realistic treatment options.

References 

1. Arnett GW, Milam SB, Gottesman L. (1996). Progressive mandibular retrusion-idiopathic condylar resorption. Part II. American Journal of Orthodontics and Dentofacial Orthopedics, 110(2), 117–127. 


2. Wolford LM, Cardenas L. (1999). Idiopathic condylar resorption: Diagnosis, treatment protocol, and outcomes. American Journal of Orthodontics and Dentofacial Orthopedics, 116, 667–677. 


3. Wolford LM. (2001). Idiopathic condylar resorption of the temporomandibular joint in teenage girls (cheerleaders’ syndrome). Proceedings (Baylor University Medical Center), 14(3), 246–252. 


4. Mercuri LG. (2008). Osteoarthritis, osteoarthrosis, and idiopathic condylar resorption. Oral and Maxillofacial Surgery Clinics of North America, 20(2), 169–183. 


5. Sansare K, Raghav M, Mallya SM, Karjodkar F. (2015). Management-related outcomes and radiographic findings of idiopathic condylar resorption: A systematic review. International Journal of Oral and Maxillofacial Surgery, 44, 209–216. 


6. Young A. (2017). Idiopathic condylar resorption: The current understanding in diagnosis and treatment. Journal of the Indian Prosthodontic Society, 17(2), 128–135. 


7. Kristensen KD, Schmidt B, Stoustrup P, Pedersen TK. (2017). Idiopathic condylar resorptions: 3-dimensional condylar bony deformation, signs, and symptoms. American Journal of Orthodontics and Dentofacial Orthopedics, 152(2), 214–223. 


8. Chigurupati R, Mehra P. (2018). Surgical management of idiopathic condylar resorption: Orthognathic surgery versus temporomandibular total joint replacement. Oral and Maxillofacial Surgery Clinics of North America, 30(3), 355–367. 


9. Burke PH. (1961). A case of acquired unilateral mandibular condylar hypoplasia. Proceedings of the Royal Society of Medicine, 54, 507–510. 


10. Katzberg RW, Tallents RH. (1985). Internal derangements of the TM joint: Findings in the pediatric age group. Radiology, 154(1), 125–127. 


11. Schellhas KP, Pollei SR, Wilkes CH. (1993). Pediatric internal derangements of the TM joint: Effect on facial development. American Journal of Orthodontics and Dentofacial Orthopedics, 104(1), 51–59. 


12. Nebbe B, Major PW, Prasad NG, Grace M, Kamelchuk LS. (1997). TMJ internal derangement and adolescent craniofacial morphology: A pilot study. Angle Orthodontist, 67(6), 407–414. 


13. Legrell PE. (1999). TM joint condyle changes after surgically induced non-reducing disk displacement. Acta Odontologica Scandinavica, 57(5), 290–300. 


14. Qadan S, Macher DJ, Tallents RH, Kyrkanides S, Moss, ME. (1999). The effect of surgically induced anterior disc displacement of the temporomandibular joint on the midface and cranial base. Clinical Orthodontic Research, 2, 124–132. 


15. Flores-Mir C, Nebbe B, Heo G, Major PW. (2006). Longitudinal study of TM joint disc status and craniofacial growth. American Journal of Orthodontics and Dentofacial Orthopedics, 130(3), 324–330. 


16. Lei J, Yap AUJ, Liu MQ, Fu KY. (2019). Condylar repair and regeneration in adolescents/young adults with early-stage degenerative temporomandibular joint disease: A randomized controlled study. Journal of Oral Rehabilitation, 46(8), 704–714. 


17. Alomar X, Medrano J, Cabratosa J, Clavero JA, Lorente M, Serra I, Monill JM, Salvador A. (2007). Anatomy of the temporomandibular joint. Seminars in Ultrasound, CT and MRI, 28(3), 170–183. 


18. Klasser G, Reyes M. (2023). Orofacial Pain: Guidelines for Assessment, Diagnosis, and Management (7th ed.), 51.