la reconstrucción de atm con reemplazo total de cadera aloplástica

8/6/2019 La reconstruccin de ATM con reemplazo total de cadera aloplstica

1/7

C L I N I C A L N O T EAustralian Dental Journal 2011; 56: 8591

doi: 10.1111/j.1834-7819.2010.01288.x

Temporomandibular joint reconstruction with totalalloplastic joint replacement

RHB Jones*

*Professor, James Cook University and Consultant Oral and Maxillofacial Surgeon to the Townsville Hospital; previously Associate Professor,School of Dentistry, The University of Adelaide and Consultant Oral and Maxillofacial Surgeon to the Royal Adelaide Hospital.

ABSTRACT

This paper is a preliminary paper which presents the early findings of an ongoing prospective trial on the use of the TMJConcepts and Biomet Lorenz total joint replacement systems for the reconstruction of the temporomandibular joint (TMJ).

Total alloplastic replacement of the TMJ has become a viable option for many people who suffer from TMJ disease wheresurgical reconstruction is indicated. Degenerative joint diseases such as osteoarthritis, rheumatoid arthritis, psoriaticarthritis, TMJ ankylosis, malunited condylar fractures and tumours can be successfully treated using this technique.

There are a number of TMJ prostheses available. Two of the joint replacement products, which have been found to bemost reliable and have FDA approval in the United States, are the TMJ Concepts system and the Biomet Lorenz system, andfor this reason they are being investigated in this study.

This study presents the findings of seven patients with a total of 12 joint replacements using either the TMJ Conceptssystem or the Biomet Lorenz joint system. Two patients (3 joints) had the TMJ Concepts system and five patients (9 joints)had the Biomet Lorenz system.

Although still early, the results were generally pleasing, with the longest replacement having been in position for threeyears and the most recent six months. The average postoperative mouth opening was 29.7 mm (range 2535 mm) with anaverage pain score of 1.7 (range 03, minimum score of 0 and maximum 10). Complications were minimal and related tosensory disturbance to the lip in one patient and joint dislocation in two patients.

Keywords: Alloplastic, replacement, temporomandibular joint.

Abbreviations and acronyms: CoCrMo = cobalt chromium molybdenum; MRI = magnetic resonance imaging; TMJ = temporomandibularjoint; UHMWPE = ultra high molecular weight polyethylene.

(Accepted for publication 23 May 2010.)

INTRODUCTION

There have been many attempts over the years atreconstruction of the TMJ with both autologous andalloplastic materials with varying degrees of success. Inparticular, the costochondral graft has been used as an

autologous joint replacement for many years and manyauthors have advocated its use.1 Costochondral graftsare still used as growth centre transplants in youngpatients but growth is variable.2,3 In addition, thecostochondral graft is often accompanied by bonyankylosis, particularly if the articular disc has beendestroyed. Various flaps and materials have been usedto replace the missing or destroyed disc but none havebeen particularly successful.4,5

The use of alloplastic materials for TMJ reconstruc-tion fell into disuse in the 1970s as a result of problemswith the KentVitek prosthesis6,7 which caused many

foreign body reactions to the proplast and teflon used in

the manufacture of the glenoid fossa component of theprosthesis.

As a result of this problem, the TMJ Concepts systemand the Biomet Lorenz system have been developed toovercome the problems of the KentVitek joint.

The TMJ Concepts total joint replacement system is a

custom-made joint consisting of a glenoid fossa com-ponent made of ultra high molecular weight polyeth-ylene (UHMWPE) fused to an unalloyed titaniumbacking which lines and is fixed to the glenoid fossawith titanium alloy screws. The mandibular condylecomponent is made from an alloy of cobalt chromiummolybdenum (CoCrMo) and the ramus out of titanium.The total system is custom-made on a bone biomodelproduced from a CT scan of the maxilla and mandibleof the patient.8,9

The Biomet Lorenz system also comes as a glenoidfossa and condyle ramus component and in this case the

glenoid fossa component is made entirely of UHMWPE 2011 Australian Dental Association 85

Australian Dental JournalThe official journal of the Australian Dental Association


2/7

and the condyle ramus component made from CoCrMoalloy. The glenoid fossa part is also fixed into positionwith titanium screws. The Biomet Lorenz system can bepurchased as a stock system or can be custom-made ifrequired.10

Both of these total joint replacement systems have

Federal Drug Administration (FDA) approval in theUnited States for TMJ replacement in humans.

The following paper discusses the use of totalalloplastic joint replacement in seven patients. Five ofthe patients had bilateral joint reconstructions and twoof the patients had single joint reconstructions, a totalof 12 joints. This paper also presents the initial resultsof a longitudinal prospective study on total alloplasticjoint reconstruction at Townsville Hospital and JamesCook University.

MATERIALS AND METHODS

Participants were recruited on the basis of havingsevere disease requiring reconstruction. In addition todisease severity, expense also limited the selection ofparticipants. Seven patients are presented who haveundergone total joint replacement with an alloplasticreconstruction. Five of these patients had bilateral jointreconstructions and two patients had unilateral jointreconstructions. Three patients had total fibrousbonyankylosis of both TMJs, one patient had severeosteoarthritis and one patient had severe rheumatoidarthritis. Of the single joint reconstructions, one patienthad a malunited fracture of the mandibular condyle andthe other had a recurrent keratocyst of the mandibularbody and ramus which required resection.

Participating patients average age was 55.7 yearswith a range from 17 to 75 years. There were twomales and five females. Table 1 indicates the diagnosisand treatment provided.

The following protocol has been used for thediagnosis and selection of patients suitable for totaljoint reconstruction.

PROTOCOL

Diagnosis

A history and clinical examination of the TMJ, musclesof mastication and the relationships between the teeth

and jaws were undertaken. Imaging included:(a) computer tomography (CT) with three-dimensionalreformats of each patient to determine the jointarchitecture and to aid with the diagnosis; and(b) magnetic resonance imaging (MRI) to determinethe nature of the disease, particularly the soft tissues,disc position and to aid with diagnosis.

Patients with a diagnosis of significant disease such asosteoarthritis, rheumatoid arthritis, psoriatic arthritis,fibrous and bony ankylosis, tumours of the TMJ, bothbenign and malignant, or who had multiple operationswere selected for possible prosthetic replacement.

Preoperative preparation

Following selection, a biomodel was made from the CTscan of the maxilla, mandible and the articulationbetween the two and if the occlusion was not to bealtered, the mandible and maxilla were fixed together inthe existing occlusion but if the occlusion was to bealtered, the two were separated so that a new occlusioncould be established.

Model surgery was then carried out on the biomodel,making sure a gap of at least 2.5 cm between theglenoid fossa and the vertical ramus of the mandiblewas made in order to accept the prosthetic components.In the case of the TMJ Concepts replacements, thesewere sent back to the company for prosthesis manu-facture. In the case of the Biomet Lorenz system, themodel was used at the time of surgery as a reference forthe placement of the stock implants.

Surgery

The surgery was carried out in a standard way using apreauricular approach to the glenoid fossa and asubmandibular approach to the mandibular ramus.

The coronoid process was removed using the sub-mandibular access in all cases. This was to remove theaction of the temporalis muscle and allow for greatermandibular opening.

In cases of ankylosis, the extent of the ectopic bonewas established preoperatively using the CT scan andclinically at the time of the operation. Once this hadbeen defined a bony cut was made below the main bodyof the ankylosis, the depth being determined by the useof the stealth navigation system (Medtronic SurgicalNavigation Technologies, Minneapolis, USA). Oncethis cut was made and the jaw opened, further bone

was removed towards the base of the skull. This was

Table 1. Diagnosis and treatment

Patient Diagnosis Treatment Replacement

1 Bilateralankylosis

Resection,gap arthroplasty

Bilateral TMJConcepts prosthesis

2 Bilateralankylosis

Resection,gap arthroplasty

Bilateral BiometLorenz prosthesis

3 Osteoarthritis Gap arthroplasty Bilateral BiometLorenz prosthesis

4 Rheumatoidarthritis

Bilateral gaparthroplasty


5 Condylarfracture

Gaparthroplasty

Unilateral BiometLorenz prosthesis

6 Recurrentkeratocyst

Resection Unilateral TMJConcepts prosthesis

7 Osteoarthritis Bilateral gaparthroplasty


86 2011 Australian Dental Association

RHB Jones


3/7

made much easier because the medial side of themandible could be protected with adequate retractionand under direct vision. By using the navigation system,surgery became more accurate and important anatom-ical structures on the inner aspect of the mandible andat the base of the skull could be protected.

Once the desired bone had been removed and thepreoperatively determined gap created, the glenoidfossa component of the prosthesis was fixed to thebase of the zygomatic arch, using titanium screws.

The ramus and condyle component was then placedin position through the submandibular incision, thecondyle seated in the glenoid fossa and then fixed to themandibular ramus using multiple titanium screws. Priorto this, intermaxillary fixation was applied in order tomaintain the occlusion, arch bars having been wired tothe teeth during the early stages of the operation.

In the case of the TMJ Concepts prosthesis, the

ramus and glenoid fossa components were custom-made and therefore fitted well with minimal contour-ing. However, the Biomet Lorenz prosthesis had to beselected at the time of surgery. Three different sizedglenoid fossa and ramus condyle components wereavailable for trial at the time of surgery and once thesize was selected, the prosthesis was fitted, usually bybone removal. The various parts were secured to theramus and glenoid fossa by titanium screws.

The wounds were sutured in layers with resorbablesutures to the deep layers and nylon to the skin. Allwounds were drained and these drains were removedon the following day.

Postoperative patient management

Intravenous antibiotics were administered prophylacti-cally (cephalothin 1 g six-hourly) for 48 hours and thenoral antibiotics for a further seven days, and intravenoussteroid (dexamethasone 8 mg BD) cover for 48 hours.Patients remained in hospital for three to five days,depending on recovery and the home situation. Inter-maxillary elastics were initially not used but wereinstituted for all patients following the two patient

dislocations in the immediate postoperative period.After discharge from hospital, all patients were reviewedweekly for the first four weeks and monthly for sixmonths, and yearly thereafter for as long as possible.

RESULTSThe early results indicate success with both types ofjoint replacement. All patients had an acceptablemandibular opening with minimal pain and no signsof implant failure as indicated by their stable occlusionand lack of open bite deformity.

Table 2 shows the outcomes and indicates themaximum opening before surgery and at the last visit(range 6 months to 3 years). The pain score is rated asan analogue scale with 0 being no pain and 10 beingextremely painful along with the score at the last visit.Open bite deformity refers to the vertical gap between

the upper and lower incisors and is an indication ofloosening or wear of the prosthesis. The dentalocclusion refers to the stability of the occlusion andtherefore the prosthesis. A trend towards a Class IImalocclusion is an indication of loosening and wear.

The results show an increase in mandibular open-ing from the preoperative average of 14.4 mm, (range225 mm), to an average opening of 29.7 mm postop-eratively (range 2535 mm) and an average pain scoreof 1.7 (range 03 with a possible maximum of 10),where as the preoperative average was 6.7 (range 38).There was no tendency towards open bite, indicatingstability of the prosthesis which is additionally demon-strated by the occlusion where there was no alteration.

Complications

There were three patients who had minor complica-tions. One patient, a 75-year-old female patient withsevere osteoarthritis, had bilateral paraesthesia of theinferior dental nerves following her surgery which wasa result of poor positioning of the ramus component ofthe prosthesis and also resulted in a Class II occlusionpostoperatively. The paraesthesia is slowly resolving.

Table 2. Outcomes

Patient

Maximum opening Pain score (analogue)

Open bitedeformity Occlusion ComplicationPreop

Postoplast visit Preop

Postoplast visit

1 8 mm 28 mm 3 years 8 3, 3 years No Class I Nil2 2 mm 35 mm 1 year 3 0, 1 year No Class I Nil3 18 mm 30 mm 2 years 8 3, 2 years No Class II Numb lip resolving, occlusal

position not correct (Class II)4 15 mm 30 mm 1 year 7 0, 1 year No Class I Nil5 18 mm 30 mm 1 year 6 0, 1 year No Class I Dislocation6 25 mm 25 mm 1 year 7 3, 1 year No Class I Dislocation7 15 mm 30 mm 6 months 8 3, 6 months No Class I Nil

2011 Australian Dental Association 87

TMJ reconstruction with alloplastic joint


4/7

Two patients had dislocation of the mandibularcondyle out of the glenoid fossa in the early postoper-ative period requiring relocation under general anaes-thesia and the placement of intermaxillary elastics forcontrol.

Representative patients

The following two patients are representative of thecohort of patients, including a representative of bothtypes of product. They indicate the nature of thedisease, the protocols used and the outcomes seen.

Patient 1

The first patient was a 65-year-old female patient whohad a long history of psoriatic arthritis and ankylosingspondylitis with minimal response to cyclosporine andmethotrexate. She had multiple gap arthroplasties,with interposition of temporalis muscle and later

dermisfat grafts. Each time the gap reduced, underthe influence of the masseter and medial pterygoidmuscles with the interposition material failing andallowing the joint to undergo re-ankylosis. Thisproduced an increasing anterior open bite as a resultof the lack of vertical ramus height and a steepmandibular plane.

It was eventually decided to reconstruct the jointswith TMJ Concepts total joint replacements. In thisinstance, and in order to increase the accuracy of theprosthesis, it was then decided to carry out the surgeryand reconstruction in two stages: stage 1 release of theankylosis by gap arthroplasty and intermaxillary fixa-

tion; and stage 2 a biomodel was constructed from theCT scans after stage 1 and bilateral prostheses wereconstructed on this biomodel and then placed intoposition as illustrated in Fig 1.

Patient 2

The second patient was a 50-year-old female patientwho suffered from osteoarthritis, pain and limitation ofjoint opening and had previous surgery for discrepositioning. She was edentulous and had only beenwearing an upper denture which was felt to becontributing to her dysfunction. This was thought tobe as a result of overclosure of her occlusal verticaldimension and therefore strain on the TMJs. In the firstinstance, her vertical dimension was corrected with newdentures using two dental implants and an over-denturein the mandible, along with a new full upper denture. Inaddition, at operation, the existence of a fibrousankylosis was found. She was treated with bilateral

alloplastic TMJ replacements of the Biomet Lorenzdesign.

In this case, a trial of virtual surgery was carried out,in order to preoperatively select the prosthesis size andto produce templates in order to more accuratelyremove the bone required at the time of surgery. Thismade the surgery more accurate and reduced the timeof the procedure (Fig 2).

DISCUSSION

TMJ disease is a common problem in the community

but the resection and replacement of the diseased TMJ

(a) (b)

(c) (d)

Fig 1. CT scan of patient 1 indicating the bony ankylosis (a), the custom prosthesis, manufactured on the biomodel after release of the ankylosis andthe production of a gap arthroplasty (b). The prosthesis in position, fossa component fixed to the zygomatic arch (c) and the ramus component fixed

to the mandible (d).


RHB Jones


5/7

is not common. The complexity of the anatomy of theTMJ presents a problem with its reconstruction andmany of the movements of the normal TMJ have notbeen reproduced in the artificial joints available.

Total joint replacement fell into disrepute becausethe early prostheses failed as a result of poor materialsselection and resultant litigation. This retarded thedevelopment of subsequent prosthetic TMJ replace-ments. However, the TMJ Concepts and Biomet Lorenzjoints have been found to be successful in manypatients. The design and materials have overcome the

problems with the previous joints but still need to beimproved if normal function is to be achieved.

These problems revolve around the failure in designof the artificial joints to replace the normal anatomicalfunction of the TMJ and also the fit of the prosthesis.The custom-design of the TMJ Concepts joint hasovercome some of the problems with fit but thefunction still needs to be improved. The Biomet Lorenzsystem comes as a stock joint with three selection sizesand therefore, a reduction in accuracy of fit. Thefunction is the same as the TMJ Concepts design andlacks translatory movements. An attempt at making

things more accurate with the latter joint was to use

virtual selection of the implant parts and the productionof templates to plan the cuts, remove the bone andimprove the fit of the prosthesis.

The TMJ is a unique joint having two joint spaces,separated by a disc made of fibro-cartilage. This discfunctions with the movements of the joint but alsoneeds to move with the joint and disc on the oppositeside in order to function correctly. Both joints arejoined by the mandible, with all of its powerful muscleattachments. In addition, the TMJ moves as a hingejoint and also by translation and in this way lateral

movements are made. It is therefore extremely difficultto reproduce the movements of the joint in theirentirety. The alloplastic joints work with hinge move-ments with no translation and therefore no lateralmovements can be expected of the total joint replace-ments currently available.

There have been a number of papers published on thebiomechanics of the TMJ1315 and it has been foundthat the centre of rotation for an ideal prosthesis isapproximately 15 mm below the centre of rotation ofthe mandibular condyle. If one rotates the mandibleabout this point, both rotatory and translatory move-

ments are made,

16

but it is difficult to produce these

(a) (b)

(c)

(a) (b)

(c)

Fig 2. Virtual selection of the glenoid fossa (a) and ramus (b) components in patient 2. They also show the amount of bone removal required fromthe ramus and condyle and from the glenoid fossa. The lower three dimensional models are of the patient with the templates in position and showing

the amount of bone to be removed at the time of surgery. The screw holes were used to place and fix the final prosthesis (c).




6/7

translatory movements with the current prostheticdesign unless a disc can be included in the joint.

There has been considerable discussion in the liter-ature about TMJ reconstruction1012 and it wouldappear that the current group of prostheses are allacceptable. So far, all of the total alloplastic TMJ

prostheses have been designed along anatomical lines,but to date there has been no effective reproduction of adisc within the joint and therefore none of them areable to reproduce translation and therefore lateralmovement.

The current designs and recommendations from themanufacturers suggest a gap of 2.5 cm between theglenoid fossa and the ramus of the mandible beingnecessary to fit the prosthesis. This arbitrary removal ofbone does not position the new mandibular condyle inan ideal location. Therefore, mandibular opening islimited to a maximum of approximately 30 mm

between the incisor teeth, with no translation and nolateral movements. However, this does not seem to be aproblem with patient acceptance as they are generallypain-free and are able to open their mouth to anacceptable degree and function relatively normally.

In addition to the biomechanical factors affecting thejoint, there are a number of other factors which need tobe considered in total joint replacement systems. Theserelate to the various materials used in their manufac-ture. These materials have been debated extensively andare generally found in the orthopaedic literature.17

In relation to hip, knee and shoulder prostheses, themetal on polyethylene articulation has been found toprovide the best results. Most orthopaedic joints aremade from CoCrMo alloy articulating withUMWPE.18,20 The metal-on-metal prostheses has onlyshown acceptable success in the hip but there are fewlong-term studies documenting their success. Metal-on-metal has not been used for any other joint inorthopaedic surgery, mainly because of the wearparticles produced by the metals. The wear particlesin the metal-on-metal prosthesis produce a foreign bodyreaction which ultimately leads to loosening and failureof the implant.19

Hypersensitivity can also present a problem, with

nickel, cobalt and chromium being the most commonsensitizing agents in humans. This hypersensitivity maybe the trigger for unfavourable outcomes with totaljoint surgery. The occurrence of metal hypersensitivityis significantly greater with the metal-on-metal jointsover those with metal on UHMWPE, as the wearparticles from these metals have been shown to be aproblem.20

Metal-on-metal joints also lead to significantly morecobalt and chromium in the body and the long-termeffects of this accumulation are not known and maylead to an increase in cell toxicity, hypersensitivity andcarcinogenesis.20

According to the orthopaedic literature, the wear ofthe component parts is a limiting factor with hip andknee prostheses and is the major reason why manypatients require revision surgery.

In contrast, the metal on UHMWPE joints haveshown very little wear in the TMJ and therefore, very

little foreign body reaction and little need for revisionsurgery. However, this is an area which may present aproblem with the current design and as such there needsto be some consideration for easy replacement of theglenoid fossa component of the prostheses.

While it does not currently appear to be a problem, atheoretical consideration with the TMJ Concepts designis the titanium backing of the glenoid fossa component,particularly with osseointegration between the glenoidfossa part of the implant and the bone of the base ofthe skull. If wear presented a problem, the integratedglenoid fossa would be difficult to remove and possible

entry into the middle cranial fossa could occur at thetime of revision surgery. In addition, if by chance thearticulating surfaces did wear through, the total jointwould require replacement as the condylar head and thefossa would be damaged.

The debate in the literature relating to the efficacy oftotal joint replacement appears to indicate that jointsmade out of CoCrMo alloy articulating with UMWPEfulfill the requirements orthopaedic surgeons haveused for artificial joint replacements in the hip, kneeand shoulder. Studies by Wolford,8,12 Mercuri11 andQuinn10 have shown the current design and manufac-ture of the TMJ Concepts and Biomet Lorenz total jointreplacements which use these materials for their TMJreconstructions have been successful in the 14 yearsthey have been following their patients.

CONCLUSIONS

This paper describes the management of seven patientsin whom 12 total alloplastic joints have been placed.The results were pleasing but long-term review isrequired. These results correlate well with the findingsof Wolford,8,12 Mercuri11 and Quinn10 in their paperson total joint replacement with alloplastic TMJs.

REFERENCES

1. MacIntosh RB. The use of autogenous tissues for temporoman-dibular joint reconstruction. J Oral Maxillofac Surg 2000;58:6369.

2. Kaban LB, Perrot DH, Fisher K. A protocol for management oftemporomandibular joint ankylosis. J Oral Maxillofac Surg1990;48:11451152.

3. Kaban LB, Bouchard C, Troulis MJ. A protocol for managementof temporomandibular joint ankylosis in children. J Oral Max-illofac Surg 2009;67:19661978.

4. Dimitroulis G. The use of dermis grafts after discectomy forinternal derangement of the temporomandibular joint. J OralMaxillofac Surg 2005;63:173178.


RHB Jones


7/7

5. Wolford LM, Morales-Ryan CA, Morales PG, Cassano DS.Autologous fat grafts placed around temporomandibular jointtotal joint prostheses to prevent heterotopic bone formation. Proc(Bayl Univ Med Cent) 2008;21:248254.

6. Kent JN, Block MS, Homsy CA, Prewitt JM, Reid R. Experiencewith a polymer glenoid fossa prosthesis for partial or total tem-poromandibular joint reconstruction. J Oral Maxillofac Surg

1986;44:520533.7. Kent JN, Block MS, Halpen J, Fontenot MG. Update on the Vitek

partial and total temporomandibular joint systems. J Oral Max-illofac Surg 1993;51:408415.

8. Wolford LM, Pitta MC, Reiche-Fischel O, Franco PF. TMJConceptstechmedica custom made TMJ total joint prosthesis:5 year follow-up study. J Oral Maxillofac Surg 2003;32:268274.

9. Mercuri LG, Wolford LM, Sanders B, White RD, Giobbie-Hur-der. A long term follow-up of the CADCAM patient fittedtemporomandibular joint reconstruction system. J Oral Max-illofac Surg 2007;65:11401148.

10. Quinn PD. Total temporomandibular joint reconstruction. OMSClinics North America 2000:93104.

11. Mercuri LG, Edibam NR, Giobbie-Hurder A. Fourteen-yearfollow-up of a patient-fitted total temporomandibular joint

reconstruction system. J Oral Maxillofac Surg 2007;65:11401148.

12. Wolford LM, Dingwerth DJ, Talwar RM, Pitta MC. Comparisonof 2 temporomandibular joint total joint prosthesis systems.

J Oral Maxillofac Surg 2003;61:685686.

13. van Loon JP. The Groningen temporomandibular joint. Gronin-gen: University of Groningen, 1999. PhD thesis.

14. Finn B. Biomechanics of the sheep temporomandibular joint.Adelaide: The University of Adelaide, 2000. MDS thesis.

15. van Loon JP, Falkenstro m CH, de Bont LG, Verkerke GJ, Steg-enga B. The theoretical optimal center of rotation for a tempo-romandibular joint prosthesis: a three-dimensional kinematicstudy. J Dent Res 1999;78:4348.

16. Falkenstrom CH. Biomechanical design of total temporoman-

dibular joint. Groningen: University of Groningen, 1993. PhDthesis.

17. Schmalzried TP, Callaghan JJ. Wear in total hip and kneereplacements. J Bone Joint Surg Am 1999;81:115136.

18. Semlitsch M, Willert HG. Properties of implant alloys for artifi-cial hip joints. Medical and Biological Engineering and Com-puting 1980;18:318.

19. Amstutz HC, Campbell P, Kossovsky N, Clarke IC. Mechanismsand clinical significance of wear debris-induced osteolysis. ClinOrthop Relat Res 1992;276:718.

20. Wolford LM. Factors to consider in joint prosthesis systems. Proc(Bayl Univ Med Cent) 2006;19:232238.

Address for correspondence:Professor Robert HB Jones

Institute of SurgeryTownsville Hospital

Townsville QLD 4810Email: [email protected]



la reconstrucción de atm con reemplazo total de cadera aloplástica

Documents