While dentists deal with aspects of, or problems with and related to the temporomandibular joint every week in our practices, we do not often meet patients who are in need of replacement of their mandibular condyle or fossa or both. As a matter of fact it would be a rare requirement to need fossa replacement alone. In teaching dental students about this joint we remind them that it is a joint like any other in the body in that disease can affect the soft and hard tissues of this unique joint just like any other. There are so many patients that present with complaints that fall under the umbrella of craniomandibular disorders that we can find ourselves prescribing treatment without having arrived first at a diagnosis. It is also very important to remember that treatment based on subjective complaints alone is not always a prudent medical principle to follow.
In approaching these patients it should be done in a systematic fashion following proper history and physical rules from ‘chief complaint and history of chief complaint’ through ‘functional inquiry, medical, dental and social histories’ to the ‘physical examination’, deciding what ‘tests’ may be required and ultimately arriving at a ‘diagnosis or differential diagnosis and treatment plan’.
With respect to this joint we can consider things that can affect it specifically just as with other body parts such as: intra-articular disorders including disc interference, fracture from trauma, osteoarthritis, inflammatory arthritis, neoplasm – both benign and malignant (including metastatic), involvement from other systemic disorders such as progressive systemic sclerosis, developmental deformations such as hemifacial microsomia, hemi mandibular hypertrophy or atrophy and finally the rather unique idiopathic condylar resorption. While some of these problems are commonplace (osteoarthritis for example) others would be rarely seen in a general dental office. This article will deal with a few examples of who may need joint replacement and what techniques are more commonly used.
Alloplastic
The earliest report of an alloplastic implant in the temporomandibular joint is that by Eggers in 1946 whereby a foil made of tantillum was placed in between the surgically separated condyle and fossa of a 4-year-old child with ankylosis.1 Christensen in 19602 developed an artificial fossa and then in 19733 developed a total prosthetic joint for the TMJ. This was the first time the TM joint was replaced with an alloplast. Others were working on variations of joint replacement at the same time and some were met with disastrous results such as the Vitek-Kent prosthesis,4 which was eventually pulled from the market. There has been an evolution of total joint prostheses over the past few decades to the present day.5,6,7
Aside from total joint replacement (i.e. condyle and fossa) many manufacturers of plates and screws provide reconstruction plates in their kits with condylar heads for condyle replacement in trauma cases or following ablative tumour surgery. These are mostly deemed temporary now since there is a risk of middle cranial fossa penetration from secondary trauma to the jaw or bony erosion over time. With the good quality of total joints presently available there is no indication for permanent prosthetic condyle without placement of a fossa component other than as a temporary measure.
Autogenous
The most common autogenous part transplanted to replace the mandibular condyle is the rib. Specifically it is the costochondral (CC) junction that is harvested along with a few cms of bony rib. Because of the cartilaginous cap at the CC junction the ‘new’ condyle can adapt to its new shape as demanded by function within the glenoid fossa. It’s biology allows it to fully integrate with the mandibular ramus and will undergo fracture as opposed to cranial cavity displacement should enough of a force be applied in an upward direction as in a severe trauma.
The first report of a CC graft was by Gillies in 1920.8 The technique has undergone an evolution in past and recent years and is still widely used today.9,10,11
Other body parts used for this purpose include the metatarsal-phalyngeal joint12 and the sternoclavicular joint.13 Most recently distraction osteogenesis has been proposed as an option to replace the condyle.14
There must be correlating physical and/or imaging findings of disease within the temporomandibular joint before one should consider its replacement. Such problems would include advanced osteoarthritis, ankylosis, dentofacial deformity with total or partial agenesis of condyle (post traumatic and not) with functional disability, tumour, inflammatory arthritis, other systemic disorders (e.g. progressive systemic sclerosis). Complaint of pain alone without a demonstrable physical problem that needs correction is not a reason for joint replacement nor should it be for any irreversible or extensive treatment. This general medical principle has been forgotten by some in dentistry!
For prosthetic total joint replacement it is necessary to open the joint with a preauricular approach for placement of the fossa component (Figure 1). It is also necessary to use a sub- or retro-mandibular approach for placement of the condylar portion (Figure 2). In contrast, when a rib graft is placed, there is obviously a need for a chest incision and it is usually the 5th or 6th rib that is harvested. Figure 3 shows the resultant healed scar from a rib harvest. In addition the same approach to the angle of mandible is required as for the total joint. However the preauricular approach is usually not required.
The following case reports will highlight a few indications where joint replacement has been indicated and the means by which that was achieved.
A 24-year-old female presents with isolated condylar resorption without history of trauma or other disease/dysfunction. Inflammatory arthritis was also ruled out. The chosen procedure was costochondral graft reconstruction and in the absence of chronic TMD. This patient did very well and maintained very good TMJ function. (Figure 3)
An 18-year-old female presented with high bilateral condylar neck fractures that had happened 3 weeks earlier. Her chief complaint was that she couldn’t get her teeth together; the panoramic radiograph shows a large anterior open bite. After it was determined that her condyles and ramal height could not be restored to a functional state as would normally be done via plating the fractures, bilateral joint reconstruction was performed with harvesting the 4th and 6th ribs on the right side. Post operatively she did very well with restoration of her pre traumatic occlusion and very good jaw opening and lateral excursions. (Figure 4)
A 38-year-old female with systemic sclerosis affecting her TM joints undergoes bilateral total joint replacement after presenting with anterior open bite malocclusion and 2 mm of mandibular opening. Post operatively she has immediate 20mm of opening and much improved occlusion. Although orthodontic appliances were placed it was impossible to obtain study models to perform proper treatment planning. (Figure 5)
Although the number of people requiring temporomandibular joint replacement is not that great, we need to remind ourselves of those special situations where this can benefit an individual. If proper case selection is utilized for rib graft
ing there can be very acceptable functional results and a permanent restoration of form. Likewise with total joint arthroplasty, the technology has evolved to the point where predictable results can enhance the lives of and overcome significant dysfunction for many of our patients. OH
Archie Morrison is Associate Professor Dalhousie University and Active Staff OMF Surgery QE II Health Sciences Centre Halifax, NS. References
1. Eggers GW. Arthroplasty of the temporomandibular joint in children with interposition of tantillum foil. J Bone Joint Surg Am 1946;28:603-7.
2. Christensen RW. The correction of mandibular ankylosis by arthroplasty and insertion of a cast vitallium glenoid fossa. J South Calif Dent Assoc 1963;31:117-8.
3. Christensen RW. The temporomandibular joint prosthesis 11 years later. Oral Implantol 1971;2:125-33.
4. Kent JN, Homsy CA, Gross BD, Hinds EC. Pilot studies of a porous implant in dentistry and oral surgery. J Oral Surg 1972;30:608-15.
5. Mercuri LG. Alloplastic temporomandibular joint reconstruction. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1998;85:631-7.
6. Quinn PD, Giannakopoulos H, Carrasco L. Management of surgical failures. Oral Maxillofacial Surg Clin N Am 2006;18(3):411-17.
7. Various authors. Oral Maxillofacial Surg Clin N Am 2000; 12(1):61-139.
8. Gillies HD. Present day plastic operations of the face. J of the National Dental Association 1920;7:3-36.
9. Poswillo DE. Biological reconstruction of the mandibular condyle. Br J Oral Maxillofac Surg 1987;25:100-4.
10. MacIntosh RB. The use of autogenous tissue in temporomandibular joint reconstruction. J Oral Maxillofac Surg 2000;58:63-9.
11. El-Sayed KM. Temporomandibular joint reconstruction with costochondral graft using modified approach. Int J Oral Maxillofac Surg. 2008;37(10):897-902
12. Dierks EJ, Buehler MJ. Complete replacement of the temporomandibular joint with a microvascular transfer of the second metatarsal-phalyngeal joint. Oral Maxillofacial Surg Clin N Am 2000;12(1):139-47.
13. Korula P, Ramchandra NE, Dhanaraj P. Temporomandibular arthroplasty by pedicled transfer of the sternoclavicular joint – a simplified technique. Br J Plast Surg 1991:44(6):410-4.
14. Cheung LK, Zheng LW, Ma L, Shi XJ. Transport distraction versus costochondral graft for reconstruction of temporomandibular joint ankylosis: which is better? Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(1):32-40.
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