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Techmedica custom-made TMJ total joint prosthesis: 5-year follow-up study
Int. J. Oral Maxillofac. Surg. 2003; 32: 268–274 doi:10.1054/ijom.2002.0350, available online at http://www.sciencedirect.com
Clinical Paper TMJ Disorders
TMJ Concepts/Techmedica custom-made TMJ total joint prosthesis: 5-year follow-up study
L. M. Wolford, M. C. Pitta, O. Reiche-Fischel, P. F. Franco Dept of Oral and Maxillofacial Surgery, Baylor University Medical Center, Baylor College of Dentistry, Texas A & M University System, Dallas, TX, USA
L. M. Wolford, M. C. Pitta, O. Reiche-Fischel, P. F. Franco: TMJ Concepts/Techmedica custom-made TMJ total joint prosthesis: 5-year follow-up study. Int. J. Oral Maxillofac. Surg. 2003; 32: 268–274. 2003 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. Abstract. This prospective study evaluated the 5 to 8 year subjective and objective results of 42 consecutive patients who had TMJ reconstruction using the TMJ Concepts/Techmedica custom made total joint prosthesis. Criteria for use of the prosthesis included the following TMJ conditions: (1) multiply operated, (2) previous alloplastic implants, (3) osteoarthritis, (4) inflammatory or resorptive arthritis, (5) connective tissue or autoimmune disease, (6) ankylosis, and (7) absent or deformed structures. Thirty-eight of 42 patients (90%) with 69 TMJs reconstructed using the TMJ Concepts/Techmedica total joint prosthesis had appropriate data for inclusion in the study. The average age at surgery was 36 years and average follow-up was 73.5 months. The entire group and three subgroups were objectively evaluated for incisal opening, lateral excursions, and occlusal stability, while subjectively assessed for pain and jaw function. Paired t-test and comparison analyses were used to assess outcomes. For the group of 38 patients, there was statistically significant improvement in incisal opening (P=0.001), jaw function (P=0.001), and pain level (P=0.0001). Lateral excursion movements significantly decreased (P=0.04). The occlusion remained stable in all cases. Complications occurred in six patients. Comparison analysis of the three groups demonstrated significantly better outcomes for patients with fewer previous TMJ surgeries and without exposure to Proplast-Teflon or Silastic TMJ implants. This study demonstrated that the TMJ Concepts/Techmedica total joint prosthesis is a viable technique for TMJ reconstruction as a primary procedure and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
Introduction Patients with specific temporomandibular joint (TMJ) conditions and pathology may benefit from TMJ reconstruction using a total joint Grants: None. This was a self-funded project. 0901-5027/03/030268+07 $30.00/0
prosthesis, including: (1) multiply operated TMJs (two or more previous surgeries), (2) previous TMJ alloplastic implants, including Proplast-Teflon (Vitek, Inc., Houston, TX, USA) and Silastic (Dow-Corning, Midland, MS, USA), (3) osteoarthritis with involve-
Key words: temporomandibular joint; TMJ; TMJ reconstruction; custom-made total joint prosthesis; multiple TMJ surgeries; Proplast-Teflon; silastic. Accepted 24 September 2002
ment of the condyle and fossa, (4) inflammatory or resorptive TMJ pathology, (5) connective tissue or autoimmune diseases affecting the TMJs (i.e., psoriatic arthritis, ankylosing spondylitis, scleroderma, Sjogren’s syndrome, rheumatoid arthritis, lupus, etc.), (6)
2003 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved.
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Fig. 1. An accurate 3-dimensional plastic model of each patient’s jaws and jaw joints was constructed from CT data. The prosthesis was manufactured from this model. The TMJ Concepts/Techmedica custom-made total joint prosthesis has two components. The fossa is composed of an anatomically contoured titanium sheet covered with titanium mesh and a UHMWPE functional component. The custom-fitted mandibular component shaft is composed of CP titanium or titanium alloy, and the condylar head is chromium-cobalt-molybdenum alloy. There is a posterior stop on the fossa component that is very important for joint function and stability.
fibrous or bony ankylosis, (7) absent or deformed anatomical structures (i.e., fractured displaced condyles, absence of condyles and portions of the ramus as the result of previous trauma, surgery, pathology, or congenital deformity), and (8) tumours involving the joint and jaw area.These conditions can create dysfunction and/or destruction of the articulation of the mandibular condyle to the glenoid fossa. Autogenous tissue grafts (i.e., costochondral, sternoclavicular, temporal myofascial, auricular cartilage, dermis, sliding ramus osteotomy) are used for TMJ reconstruction in many of these conditions. However, since some of these conditions can have an adverse affect on autogenous grafts, a significant incidence of failure may occur with their use4,12,13. These pathological dysfunctional and deforming conditions can significantly alter the anatomy in the TMJ area and mandibular ramus. Also, mandibular advancement and/or counterclockwise rotation (rotating the anterior aspect of the maxillomandibular complex upwards and the posterior aspect downwards) may be necessary to correct the dentofacial deformity associated with or created by the TMJ condition in order to obtain optimal functional and esthetic results. These repositioning movements
can create a large gap between the fossa and mandibular ramus/condyle structures. In these circumstances, a custommade total joint prosthesis can provide accurate adaptation to the anatomical structures of each individual patient13. The custom-made total joint prostheses used in this study, were originally developed in 1989 by Techmedica Inc., Camarillo, CA, USA, and are currently manufactured by TMJ Concepts, Inc., Ventura, CA, USA. These prostheses were CAD/CAM devices (computer assisted design/computer assisted manufacture), designed to fit the specific anatomical requirements for each patient. The following characteristics are very important for a total joint prosthesis to be successful: (1) biocompatible materials, (2) functionally compatible materials, (3) low wear, flow, and fatigue coefficients when loaded under functional conditions, (4) adaptability to anatomical structures, (5) rigidly stabilized components, and (6) corrosion resistant and non-toxic. Materials and methods Prosthesis specifications
The TMJ Concepts/Techmedica TMJ prosthesis design principles and
materials are those that have been proven highly successful in orthopedics. Following a specific CT scan protocol, the CT scan data was processed through a rapid prototyping technology system to produce an anatomically accurate plastic model of the jaws and joints. This model allowed selective repositioning of the mandible on the model into a predetermined functional and esthetic position, as well as performing a condylectomy and recontouring the fossa and ramus as necessary. The repositioning, condylectomy, and recontouring on the model would later have to be reproduced accurately on the patient at the time of surgical intervention for insertion of the prosthesis. The custommade total joint prosthesis was then constructed on this model (Fig. 1). The fossa component was made of two basic materials. A custom fitted, commercially pure (CP) titanium sheet was constructed to conform to the anatomy of the fossa, articular eminence, and lateral aspect of the fossa and adjacent arch. Four layers of titanium mesh were bonded to both sides of the sheet by a special diffusion bonding process. The purpose of the mesh was to allow bone and soft tissue ingrowth from the fossa to maximize long-term stability of the fossa component and to secure the
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Fig. 2. The fossa component custom-fitted titanium sheet is covered with four layers of titanium mesh and fits against the bony fossa and arch area to facilitate bone and soft tissue ingrowth to maximize stabilization. The UHMWPE also attaches to the mesh and provides the fossa articulating surface.
articulating surface composed of ultra high molecular weight polyethylene (UHMWPE), to the fossa titanium base (Fig. 2). The UHMWPE had a relatively flat functional surface and had a posterior stop to provide a centric relation position for the condylar head of the prosthesis. The mandibular component (mandibular shaft and condyle) was constructed from two basic materials. For the mandibular shaft there was a choice of either wrought CP titanium or wrought titanium alloy composed of 90% titanium, 6% aluminium, and 4% vanadium. The CP titanium provided some manipulative bending characteristics to aid in adjusting the prosthesis if necessary. The titanium alloy was very resistant to bending. Therefore, any adjustments necessary to adapt the alloy shaft required alteration of underlying bone. The CP titanium was used in almost all of the prostheses in this study. The functional condyle of the mandibular component was constructed of wrought chromium-cobalt-molybdenum alloy that consisted of approximately 64% cobalt, 28% chromium, 6% molybdenum, and 2% trace elements of nickel, iron, carbon, silicone, manganese and nitrogen. The functional surfaces of the chromium-cobalt-molybdenum alloy and the UHMWPE represent the gold standard for orthopedic joint
replacement in terms of wear and structural stability. Surgical technique
The TMJ was approached through a preauricular or endaural incision. A condylectomy was performed, the area debrided, and bony recontouring of the fossa was completed if indicated. A coronoidectomy was done to release the temporalis muscle when the mandible was advanced (greater than 5 mm) or vertically lengthened posteriorly. A submandibular incision was used to gain access to the mandibular ramus, reflect the masseter muscle, detach the medial pterygoid muscle when indicated (advancements and posterior vertical lengthening), and perform bony recontouring of the ramus when necessary. The mandible was appropriately mobilized, an occlusal splint placed if indicated, and intermaxillary fixation applied. The fossa component of the prosthesis was then inserted and stabilized to the zygomatic arch with 3 to 4, 2.0 mm diameter bone screws. The mandibular component was placed through the submandibular incision and stabilized with 4 to 12, 2 mm diameter bone screws. The intermaxillary fixation was released and the occlusion checked for proper interdigitation. The incisions were then closed in the usual manner.
Patients were routinely covered with antibiotics (usually a cephalosporin) intraoperatively and for 3 weeks post surgery. Patients and methods
This 5 year prospective study evaluated the first 42 consecutive patients, treated with TMJ Concepts/Techmedica custom-made total joint prostheses, operated by one surgeon. There were 38 of 42 patients (90%) (37 F, 1 M) that returned for clinical and radiographic evaluation. Four patients did not return for follow-up evaluations and therefore, were excluded from the study. None of these four patients were known to have any significant surgery related complications. In the 38 patients, there were 69 TMJs that underwent total joint reconstruction using the TMJ Concepts/ Techmedica custom-made total joint prostheses. The average age was 36 years with a range of 15 to 64 years. The follow-up average was 73.5 months with a range of 60 to 96 months. The average number of previous TMJ surgeries was 2.9 with a range of 0 to 16. The patients were divided into three groups according to the number of previous TMJ surgeries and previous use of Proplast-Teflon or Silastic (PT-S) TMJ implants (Table 1). Group 1 (n=6) included patients with 0 to 1 prior TMJ surgeries and no previous
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Table 1. Demographics
Group 1 (0 to 1 previous TMJ surgery) Group 2 (2 or more previous TMJ surgeries) Group 3 (previous TMJ surgery with PT-S*) Total
No. of patients
No. of joints
No. previous surgery
Complications
6 6 26 38
11 12 46 69
0.8; range 0 to 1 2.5; range 2 to 4 3.5; range 1 to 16 2.9 range 0 to 16
1 (BH) 1 (HB) 4 (3HB, 1LMC) 6
*PT-S=Previous proplast-teflon or silastic TMJ implants; HB=heterotopic bone; LMC=loose mandibular component.
alloplastic implants. Group 2 (n=6) included patients with 2 or more previous TMJ surgeries and no previous alloplastic implants. Group 3 (n=26) consisted of patients who had 1 or more previous TMJ surgeries with PT-S placed in the joints. The patients were evaluated clinically by a single investigator, with data recorded on standard forms, for maximum incisal opening, maximum lateral excursions, and occlusal stability at the following intervals: presurgery; postsurgery at 3, 6, 12, 24, 36 months, and at the longest follow-up beyond 5 years. Visual analogue scales (VAS) were used to subjectively evaluate pain levels (0=no pain, 10=worst pain) and jaw function (0=normal function, 10=no function). Functionally, the patients evaluated their ability to chew and perform mandibular movements. Occlusal stability was assessed by cephalometric analysis and by recording the immediate postoperative clinical occlusal relationship and comparing the long-term results relative to Angle’s classification and overbite/ overjet relationships. Descriptive statistics and paired t-tests (P<0.05) were used to compare presurgery and longest postoperative follow-up data. Due to the small sample size, no valid statistical comparison could be used on groups one and two; therefore, all three groups were combined into one group for statistical analysis. Results The patient demographics and pre- and postoperative values of the total group of 38 patients can be seen in Tables 1 and 2. The mean preoperative incisal opening was 27.5 mm (SD 11.1; range 4 to 50 mm) and the mean postoperative incisal opening was 32.6 mm (SD 9.4; range 4 to 56 mm) showing statistically significant improvement at long-term follow-up (P<0.001). The mean preoperative lateral excursive movement was 2.1 mm (SD 2.8; range 0 to 5 mm) with a postoperative mean of 1.7 mm (SD 1.7; range 0 to 3 mm) demonstrating a statistically significant decrease (P<0.04).
The mean subjective VAS preoperative pain level was 7.7 (SD 2.3; range 5.4 to 10) and the mean postoperative pain level was 3.6 (SD 3.1; range 0.5 to 6.7) showing a statistically significant decrease in pain (P<0.0001). The mean preoperative VAS subjective jaw function score was 7.1 (SD 2.3; range 4.8 to 9.4) and the mean postoperative function score was 4.5 (SD 2.3; range 2.2 to 6.8) showing a statistically significant functional improvement (P<0.0001). Long-term occlusion has remained stable in all patients, as compared to the immediate postsurgical occlusal relationship. Some minor tooth positional changes occurred in some patients who were under orthodontic treatment at the time of surgery. Complications encountered included: loosening of one mandibular component, which had only four 2.0 mm diameter titanium screws stabilizing it, in a patient with uncontrolled bruxism, and had to be replaced with a new mandibular component stabilized with 8, 2.0 mm diameter titanium screws. This device has remained stable for over 8 years. Five patients had heterotopic bone formation and required reoperation to remove the bone. In comparing the three groups, we observed that the number of previous TMJ surgeries and exposure to PT-S affected outcomes (Table 3). At the longest follow-up, Group 1 showed greater incisal opening of 39.8 mm (range 27 to 56 mm) and Group 2 had 33.6 mm (range 20 to 45 mm). Although Group 3 had the greatest improvement in incisal
opening (6.3 mm); the group still had the lowest long-term incisal opening at only 30.5 mm (range 4 to 45 mm). The longest follow-up lateral excursion movement was slightly better for Group 1 at 2.3 mm, with Group 2 at 1.5 mm and Group 3 at 1.7 mm, demonstrating a significant reduction for Group 1 and a moderate reduction for Groups 2 and 3. The final average pain level for Group 1 was 1.6 (range 0 to 3), Group 2 was 5.1 (range 0 to 9) and Group 3 was 4.0 (range 0 to 9), where the lower number indicates less pain. The average subjective postoperative jaw function level was better in Group 1 with 3.1 (range 0 to 6) as compared to Group 2 with 4.5 (range 2 to 8) and Group 3 with 4.8 (range 0 to 9), where a lower number indicates better jaw function.
Discussion Techmedica, Inc. developed the TMJ Concepts/Techmedica total joint prosthesis in 1989 as a custom-made TMJ total joint prosthesis. In July 1993, the United States Food and Drug Administration (FDA) halted the manufacture of any TMJ devices developed after 1976, due to lack of safety and efficacy information to support its indicated use. Based on outcomes of this original 5 year study, and the technical merit of design and materials, this product was approved by the FDA to be marketed in July of 1996 by TMJ Concepts Inc. This is the first TMJ total joint device to go through and pass the rigors of FDA
Table 2. Results (38 patients) Mean (SD) Incisal opening Lateral excursion Pain (0=no pain; 10=worst pain) Jaw function (0=normal function; 10=no function)
Preop
Postop
27.5 mm (11) Range 4 to 50 mm 2.1 mm (2.8) Range 0 to 5 mm 7.7 (2.3) Range 5.4 to 10 7.1 (2.3) Range 4.8 to 9.4
32.6 mm (9.4)** Range 4 to 56 mm 1.7 mm (1.7)* Range 0 to 3 mm 3.6 (3.1)** Range 0.5 to 6.7 4.5 (2.3)** Range 2.2 to 6.8
*Statistically significant P<0.05, **statistically significant P<0.001.
24.2 (range 4–40) 30.5 (range 4–45) 2.0 (range 0–11) 1.7 (range 0–3) 7.8 (range 2–10) 4.0 (range 0–9) 7 (range 2–10) 4.8 (range 0–9) 3 Heterotopic bone 1 Loose mandibular component 32.3 (range 12–42) 33.6 (range 20–45) 2.2 (range 0–5) 1.5 (range 0–3) 7.5 (range 5–10) 5.1 (range 0–9) 7.8 (range 5–10) 4.5 (range 2–8) 1 Heterotopic bone *Number of patients.
37 (range 29–50) 39.8 (range 27–56) 4.0 (range 1–8) 2.3 (range 1–3) 7.3 (range 3–9) 1.6 (range 0–3) 7 (range 2–10) 3.1 (range 0–6) 1 Heterotopic bone Incisal opening (mm) Lateral excursion (mm) Pain (0=no pain; 10=worst pain) Jaw function (0=normal function; 10=no function) Complications*
Preop
Group 1 (n=6)
Postop
Preop
Group 2 (n=6)
Postop
Preop
Group 3 (n=26) Postop
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Table 3. Results
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scrutiny. This device uses materials that are well proven in orthopedic joint reconstruction for hip and knee replacements. Although the life expectancy of this device is unknown, based on material selection, treatment philosophy, and this study, these devices have provided the service life of 8 years without evidence of untoward wear or failure. Patients who have received previous TMJ implants, including ProplastTeflon (PT), Silastic (S), or bone cements may have particulization of those materials with migration and penetration into the adjacent bone and soft tissues4,5,7,9,10. It is extremely difficult, if not impossible, to totally remove all of the microscopic particles from the area with surgical debridement. The residual particles can lead to foreign body giant cell reaction that can affect autogenous grafts causing degenerative changes. H & W4 reported a study on 107 patients where autogenous tissues were used to reconstruct the TMJ when previous Proplast-Teflon (PT) had been placed. Long-term evaluations (4 years) for pain, occlusal stability, and jaw function with autogenous grafts for TMJ reconstruction identified the following success rates for each of the tissues used for grafting: Costochondral (12%), sternoclavicular (21%), dermal (8%), temporal fascia (13%), temporal fascia with mandibular sagittal split osteotomies (31%), and auricular cartilage (25%). This study also showed a significant increase in failure rates for all autogenous tissue groups as the number of prior TMJ surgeries increased. After two previous TMJ surgeries, the long term success rate for autogenous tissue grafts approached zero. Ankylosis (decreased function) and pain were the most common causes of failure. Autoimmune, connective tissue, and inflammatory diseases can also attack autogenous grafts in the TMJ area if the joint is involved in the disease process. W et al.12 used sternoclavicular grafts in three different patient types: (1) those with previous PT-S implants, (2) autoimmune, connective tissue, or inflammatory disease processes (i.e. Rheumatoid arthritis, psoriatic arthritis, lupus, Sjogrens, reactive arthritis, spondyloarthropathies), and (3) noninflammatory, non-PT-S TMJ pathology (i.e. previous fractures, congenital deformities). The success rate was 29% in the PT-S joints, 50% in inflammatory disease processes, and 93% in joints with non-inflammatory, non-PT-S pathology. Similar results may occur with other
autogenous grafts when used in joints with previous alloplasts, inflammatory, connective tissue, and autoimmune diseases. In autogenous reconstruction for fibrous or bony ankylosis, the chances of redeveloping heterotopic bone, reactive bone, and/or fibrosis with subsequent reankylosis are very high. The use of a custom-made total joint prosthesis may improve the results in many of these conditions. Patients subjected to multiple (2 or more) surgical procedures will have predictably poorer outcomes compared to those with 0 to 1 previous surgeries, particularly in using autogenous tissues for TMJ reconstruction1,11,13. The more surgeries, the worse the prognosis. Likewise, with total joint prosthesis, the prognosis is worse, particularly related to alleviation of pain11,13. Multiple TMJ operations create scar tissue, interrupt normal blood flow and normal physiologic nutritional distribution to the anatomical structures. This results in degradation of the fibrocartilage, bony structures, articular disc, capsular ligaments, neurogenic components, and associated musculature, that can lead to joint dysfunction, TMJ pain, headaches, myofacial pain, and jaw deformities. Multiple surgeries may establish an environment conducive to a bacterial/ viral reactive arthritis, sympathetic mediated pain, autoimmune polyneuropathy, chronic joint inflammatory disease, etc.11. The high failure rate in using autogenous tissues in the multiply operated TMJ indicates that the custommade total joint prosthesis may be a better alternative for reconstruction of these joints. W et al.13 published a study on 56 patients (55 females, 1 male) with 100 reconstructed temporomandibular joints, using the TMJ Concepts/ Techmedica custom-made total joint prosthesis system. The patients’ average age was 39 years (range 15 to 61 years) and had an average follow-up of 30 months (range 16 to 46 months). The outcomes were categorized as good, fair, or poor, based on clinical and radiographic assessment for pain, incisal opening, and occlusal stability. The results showed that 35 patients (63%) with 58 joints (58%) had a good outcome, 13 patients (23%) with 26 joints (26%) had a fair outcome, and 8 patients (14%) with 16 joints (16%) had a poor outcome. Patients with zero to one previous TMJ surgeries had 86% in the good group, and 16% in the fair group, and no patients in the poor group. In
TMJ concepts total joint prosthesis patients with two or more previous TMJ surgeries, the success rate decreased to 55% with good results, 26% with fair results, and 19% with poor results. Continued pain was the major factor that placed patients in the poor result group which may be related to problems such as cervical neuropathy, residual inflammatory or foreign body giant cell reaction, immunological reaction to alloplastic particles, fibrosis, calcification, heterotopic or reactive bone formation, sympathetic mediated pain, autoimmune polyneuropathy, multiple chemical sensitivity, bacterial/viral contamination, and/or other unidentified factors11. The TMJ Concepts/Techmedica custom-made total joint prosthesis was previously evaluated by H & W4, to determine the outcome in patients with a history of ProplastTeflon TMJ implants. Twenty-six patients (43 joints) were evaluated, with a follow-up from 4 to 24 months. The TMJ Concepts/Techmedica custommade total joint prosthesis provided an 86% success rate relative to stability and function, with a level of residual pain rated as good in 46%, fair 38%, and poor in 16% of the patients. The average postoperative incisal opening in this group was 26 mm at 6 months, 26 mm at 12 months, 32 mm at 18 months, and 35 mm beyond 18 months. M et al.6 published a prospective study on 215 patients (202 females, 13 males) that were reconstructed with the TMJ Concepts/Techmedica total joint prosthesis. The average age at reconstruction was 40.9 years (range 15 to 77 years). There were 363 joints placed, 296 bilateral (148 patients) and 67 unilateral. The patients had TMJ problems for an average of 10.7 years (range 1 to 44 years) prior to surgery, and had undergone a mean of 5.4 (range 0 to 28) prior unsuccessful surgeries. Preoperative and postoperative data were collected for up to 48 months, using a standardized collection format. The results showed statistically significant changes in subjective evaluations including decrease in pain, increase in jaw function, and improvement in diet (P<0.0001). There was also an improvement in incisal opening. The number of previous surgeries was a strong predictor of postoperative pain, function, and diet scores, as well as maximal incisal opening, with an increased number of previous surgeries resulting in poorer outcomes. A lifetime table analysis was performed, indicating good durability of the prosthesis over time. The study
demonstrated that the TMJ Concepts/ Techmedica custom-made total joint prosthesis was useful in the treatment of multiply operated and anatomically mutilated TMJ patients. Five of the TMJ patients in this study have required additional TMJ surgical procedures, following reconstruction with the total joint prosthesis, for removal of fibrotic tissue, continued foreign body giant cell reactions secondary to Proplast-Teflon and Silastic implants, and/or removal of heterotopic and reactive bone. In the surgical re-examining of these joints, there was no visual evidence of wear or cracking of the UHMWPE surface or the chromium-cobalt-molybdenum condylar head. The longest postsurgery time for patient evaluation in this manner was 8.2 years. Histological evaluation of intercapsular tissues taken from those patients with no previous PT-S TMJ implants, showed no evidence of wear debris or foreign body giant cell reaction, confirming the high quality wear characteristics of the prosthesis. In this present study, lateral excursion movements decreased in all three groups. This decrease was likely due to required condylectomy, detachment of the lateral pterygoid muscle to remove the condyle, and subsequent fibrosis and heterotopic/reactive bone that can form around the TMJ prostheses. In approximately 60% of the patients in this study, the lateral pterygoid muscle was reattached to the neck of the prosthesis by permanent sutures, but this did not appreciably improve excursive movements. A common problem with TMJ prostheses is the development of fibrosis and reactive/heterotopic bone around the prostheses, causing pain and limited jaw function. In patients with previous PT-S TMJ implants, the foreign body giant cell reaction can continue because the particulated materials cannot be completely removed. W & K14 have reported a technique of placing a fat graft (harvested from the abdomen or the buttocks) around the TMJ total joint prosthesis to eliminate the dead space. Eliminating the dead space prevents blood clot formation, which otherwise could provide a matrix for the fibrous ingrowth and pluri potential cells migrating into the area that could develop bony and dense fibrous tissues. Also, in patients with previous alloplastic implants, the fat graft blocks out a large area in which foreign body giant cell reaction may otherwise
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redevelop. None of the patients in the study presented herein, had fat grafts placed around the prostheses at the time of TMJ total joint reconstruction, as advocated by some authors8,14, nor was any radiation therapy utilized to inhibit heterotopic bone formation as recommended by others2,3, W & K14 reported on 15 consecutive patients (22 joints) with TMJ Concepts/ Techmedica total joint prostheses, where fat grafts were packed around the joint area and compared the outcomes with 20 consecutive patients (37 joints) treated prior to initiation of the fat graft technique. The patients with fat grafts had improved incisal opening and excursive movements, as well as some decrease in pain. In addition, none of the patients receiving the fat grafts had to be taken back to surgery for removal of fibrous tissue or heterotopic bone as compared to about 30% of the non-grafted group. This technique demonstrates a major improvement in the outcome of patients requiring TMJ total joint prosthesis reconstruction. Two patients had a biopsy of their fat grafts, one at 4 months, and one at 12 months, showing good viability of the fat tissues14. This study demonstrates that the TMJ Concepts/Techmedica total joint prosthesis works well long-term (5 to 8 years of follow-up), and is a viable technique for TMJ reconstruction, as a primary procedure when indicated, and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
References 1. B JP, I AT. Failure Rates of Repetitive Temporomandibular Joint Surgical Procedures. Presented at the American Association of Oral and Maxillofacial Surgeons 74th Annual Meeting. Scientific Poster Session III held in Honolulu, Hawaii. September 1992 (abstract). J Oral Maxillofac Surg 1992: 50: 145. 2. D ED, T EG. Radiation treatment of heterotopic bone formation in the temporomandibular joint articulation. Int J Radiol Oncol Phys 1993: 27: 863–869. 3. F RJ, A AQ. Single dose 6 Gy prophylaxis for heterotopic ossification after total hip arthroplasty. Clin Orth 1995: 317: 131–140. 4. H CH, W LM. Treatment outcomes for temporomandibular joint reconstruction after proplast-teflon implant failure. J Oral Maxillofac Surg 1993: 51: 352–358.
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5. J M, S E. Wear particles of total joint replacements and their role in periprosthetic osteolysis. Curr Opinion Rheumatol 1992: 4: 204–209. 6. M LG, W LM, S B, W RD, H A, H W. Custom CAD/CAM total temporomandibular joint reconstruction system: Preliminary report. J Oral Maxillofac Surg 1995: 53: 106–115. 7. S M. Biomaterial failure. Orthop Clin North Am 1992: 12: 211–217. 8. T BJ. Heterotopic bone formation after total hip arthroplasty. Orthop Clin North Am 1992: 23: 347–358. 9. W PS, B PG. The effects of friction and wear in artificial joints. Orthop Clin North Am 1973: 4: 275–293.
10. W DF. Tissue reaction to metallic corrosion products and wear particles in clinical orthopedics. In: Williams DF, ed.: Biocompatibility of Orthopedic Implants. Vol I: Boca Raton, FL: CRC 1982: 231–248. 11. W LM. Temporomandibular joint devices: treatment factors and outcomes. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997: 83: 143–149. 12. W LM, C DA, H CH. Sternoclavicular grafts for TMJ reconstruction. J Oral Maxillofac Surg 1994: 52: 119–128. 13. W LM, C DA, H CH. Temporomandibular joint reconstruction of the complex patient with the techmedica custom-made total joint
prosthesis. J Oral Maxillofac Surg 1994: 52: 2–10. 14. W LM, K SC. Autologous fat transplantation around TMJ total joint prosthesis: preliminary treatment outcomes. J Oral Maxillofac Surg 1997: 55: 245–251. Address: Larry M. Wolford 3409 Worth St. Suite #400 Dallas TX 75246 USA Tel: (214) 828-9115 Fax: (214) 828-1714 E-mail: [email protected]
Clinical Paper TMJ Disorders
TMJ Concepts/Techmedica custom-made TMJ total joint prosthesis: 5-year follow-up study
L. M. Wolford, M. C. Pitta, O. Reiche-Fischel, P. F. Franco Dept of Oral and Maxillofacial Surgery, Baylor University Medical Center, Baylor College of Dentistry, Texas A & M University System, Dallas, TX, USA
L. M. Wolford, M. C. Pitta, O. Reiche-Fischel, P. F. Franco: TMJ Concepts/Techmedica custom-made TMJ total joint prosthesis: 5-year follow-up study. Int. J. Oral Maxillofac. Surg. 2003; 32: 268–274. 2003 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved. Abstract. This prospective study evaluated the 5 to 8 year subjective and objective results of 42 consecutive patients who had TMJ reconstruction using the TMJ Concepts/Techmedica custom made total joint prosthesis. Criteria for use of the prosthesis included the following TMJ conditions: (1) multiply operated, (2) previous alloplastic implants, (3) osteoarthritis, (4) inflammatory or resorptive arthritis, (5) connective tissue or autoimmune disease, (6) ankylosis, and (7) absent or deformed structures. Thirty-eight of 42 patients (90%) with 69 TMJs reconstructed using the TMJ Concepts/Techmedica total joint prosthesis had appropriate data for inclusion in the study. The average age at surgery was 36 years and average follow-up was 73.5 months. The entire group and three subgroups were objectively evaluated for incisal opening, lateral excursions, and occlusal stability, while subjectively assessed for pain and jaw function. Paired t-test and comparison analyses were used to assess outcomes. For the group of 38 patients, there was statistically significant improvement in incisal opening (P=0.001), jaw function (P=0.001), and pain level (P=0.0001). Lateral excursion movements significantly decreased (P=0.04). The occlusion remained stable in all cases. Complications occurred in six patients. Comparison analysis of the three groups demonstrated significantly better outcomes for patients with fewer previous TMJ surgeries and without exposure to Proplast-Teflon or Silastic TMJ implants. This study demonstrated that the TMJ Concepts/Techmedica total joint prosthesis is a viable technique for TMJ reconstruction as a primary procedure and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
Introduction Patients with specific temporomandibular joint (TMJ) conditions and pathology may benefit from TMJ reconstruction using a total joint Grants: None. This was a self-funded project. 0901-5027/03/030268+07 $30.00/0
prosthesis, including: (1) multiply operated TMJs (two or more previous surgeries), (2) previous TMJ alloplastic implants, including Proplast-Teflon (Vitek, Inc., Houston, TX, USA) and Silastic (Dow-Corning, Midland, MS, USA), (3) osteoarthritis with involve-
Key words: temporomandibular joint; TMJ; TMJ reconstruction; custom-made total joint prosthesis; multiple TMJ surgeries; Proplast-Teflon; silastic. Accepted 24 September 2002
ment of the condyle and fossa, (4) inflammatory or resorptive TMJ pathology, (5) connective tissue or autoimmune diseases affecting the TMJs (i.e., psoriatic arthritis, ankylosing spondylitis, scleroderma, Sjogren’s syndrome, rheumatoid arthritis, lupus, etc.), (6)
2003 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Science Ltd. All rights reserved.
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Fig. 1. An accurate 3-dimensional plastic model of each patient’s jaws and jaw joints was constructed from CT data. The prosthesis was manufactured from this model. The TMJ Concepts/Techmedica custom-made total joint prosthesis has two components. The fossa is composed of an anatomically contoured titanium sheet covered with titanium mesh and a UHMWPE functional component. The custom-fitted mandibular component shaft is composed of CP titanium or titanium alloy, and the condylar head is chromium-cobalt-molybdenum alloy. There is a posterior stop on the fossa component that is very important for joint function and stability.
fibrous or bony ankylosis, (7) absent or deformed anatomical structures (i.e., fractured displaced condyles, absence of condyles and portions of the ramus as the result of previous trauma, surgery, pathology, or congenital deformity), and (8) tumours involving the joint and jaw area.These conditions can create dysfunction and/or destruction of the articulation of the mandibular condyle to the glenoid fossa. Autogenous tissue grafts (i.e., costochondral, sternoclavicular, temporal myofascial, auricular cartilage, dermis, sliding ramus osteotomy) are used for TMJ reconstruction in many of these conditions. However, since some of these conditions can have an adverse affect on autogenous grafts, a significant incidence of failure may occur with their use4,12,13. These pathological dysfunctional and deforming conditions can significantly alter the anatomy in the TMJ area and mandibular ramus. Also, mandibular advancement and/or counterclockwise rotation (rotating the anterior aspect of the maxillomandibular complex upwards and the posterior aspect downwards) may be necessary to correct the dentofacial deformity associated with or created by the TMJ condition in order to obtain optimal functional and esthetic results. These repositioning movements
can create a large gap between the fossa and mandibular ramus/condyle structures. In these circumstances, a custommade total joint prosthesis can provide accurate adaptation to the anatomical structures of each individual patient13. The custom-made total joint prostheses used in this study, were originally developed in 1989 by Techmedica Inc., Camarillo, CA, USA, and are currently manufactured by TMJ Concepts, Inc., Ventura, CA, USA. These prostheses were CAD/CAM devices (computer assisted design/computer assisted manufacture), designed to fit the specific anatomical requirements for each patient. The following characteristics are very important for a total joint prosthesis to be successful: (1) biocompatible materials, (2) functionally compatible materials, (3) low wear, flow, and fatigue coefficients when loaded under functional conditions, (4) adaptability to anatomical structures, (5) rigidly stabilized components, and (6) corrosion resistant and non-toxic. Materials and methods Prosthesis specifications
The TMJ Concepts/Techmedica TMJ prosthesis design principles and
materials are those that have been proven highly successful in orthopedics. Following a specific CT scan protocol, the CT scan data was processed through a rapid prototyping technology system to produce an anatomically accurate plastic model of the jaws and joints. This model allowed selective repositioning of the mandible on the model into a predetermined functional and esthetic position, as well as performing a condylectomy and recontouring the fossa and ramus as necessary. The repositioning, condylectomy, and recontouring on the model would later have to be reproduced accurately on the patient at the time of surgical intervention for insertion of the prosthesis. The custommade total joint prosthesis was then constructed on this model (Fig. 1). The fossa component was made of two basic materials. A custom fitted, commercially pure (CP) titanium sheet was constructed to conform to the anatomy of the fossa, articular eminence, and lateral aspect of the fossa and adjacent arch. Four layers of titanium mesh were bonded to both sides of the sheet by a special diffusion bonding process. The purpose of the mesh was to allow bone and soft tissue ingrowth from the fossa to maximize long-term stability of the fossa component and to secure the
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Fig. 2. The fossa component custom-fitted titanium sheet is covered with four layers of titanium mesh and fits against the bony fossa and arch area to facilitate bone and soft tissue ingrowth to maximize stabilization. The UHMWPE also attaches to the mesh and provides the fossa articulating surface.
articulating surface composed of ultra high molecular weight polyethylene (UHMWPE), to the fossa titanium base (Fig. 2). The UHMWPE had a relatively flat functional surface and had a posterior stop to provide a centric relation position for the condylar head of the prosthesis. The mandibular component (mandibular shaft and condyle) was constructed from two basic materials. For the mandibular shaft there was a choice of either wrought CP titanium or wrought titanium alloy composed of 90% titanium, 6% aluminium, and 4% vanadium. The CP titanium provided some manipulative bending characteristics to aid in adjusting the prosthesis if necessary. The titanium alloy was very resistant to bending. Therefore, any adjustments necessary to adapt the alloy shaft required alteration of underlying bone. The CP titanium was used in almost all of the prostheses in this study. The functional condyle of the mandibular component was constructed of wrought chromium-cobalt-molybdenum alloy that consisted of approximately 64% cobalt, 28% chromium, 6% molybdenum, and 2% trace elements of nickel, iron, carbon, silicone, manganese and nitrogen. The functional surfaces of the chromium-cobalt-molybdenum alloy and the UHMWPE represent the gold standard for orthopedic joint
replacement in terms of wear and structural stability. Surgical technique
The TMJ was approached through a preauricular or endaural incision. A condylectomy was performed, the area debrided, and bony recontouring of the fossa was completed if indicated. A coronoidectomy was done to release the temporalis muscle when the mandible was advanced (greater than 5 mm) or vertically lengthened posteriorly. A submandibular incision was used to gain access to the mandibular ramus, reflect the masseter muscle, detach the medial pterygoid muscle when indicated (advancements and posterior vertical lengthening), and perform bony recontouring of the ramus when necessary. The mandible was appropriately mobilized, an occlusal splint placed if indicated, and intermaxillary fixation applied. The fossa component of the prosthesis was then inserted and stabilized to the zygomatic arch with 3 to 4, 2.0 mm diameter bone screws. The mandibular component was placed through the submandibular incision and stabilized with 4 to 12, 2 mm diameter bone screws. The intermaxillary fixation was released and the occlusion checked for proper interdigitation. The incisions were then closed in the usual manner.
Patients were routinely covered with antibiotics (usually a cephalosporin) intraoperatively and for 3 weeks post surgery. Patients and methods
This 5 year prospective study evaluated the first 42 consecutive patients, treated with TMJ Concepts/Techmedica custom-made total joint prostheses, operated by one surgeon. There were 38 of 42 patients (90%) (37 F, 1 M) that returned for clinical and radiographic evaluation. Four patients did not return for follow-up evaluations and therefore, were excluded from the study. None of these four patients were known to have any significant surgery related complications. In the 38 patients, there were 69 TMJs that underwent total joint reconstruction using the TMJ Concepts/ Techmedica custom-made total joint prostheses. The average age was 36 years with a range of 15 to 64 years. The follow-up average was 73.5 months with a range of 60 to 96 months. The average number of previous TMJ surgeries was 2.9 with a range of 0 to 16. The patients were divided into three groups according to the number of previous TMJ surgeries and previous use of Proplast-Teflon or Silastic (PT-S) TMJ implants (Table 1). Group 1 (n=6) included patients with 0 to 1 prior TMJ surgeries and no previous
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Table 1. Demographics
Group 1 (0 to 1 previous TMJ surgery) Group 2 (2 or more previous TMJ surgeries) Group 3 (previous TMJ surgery with PT-S*) Total
No. of patients
No. of joints
No. previous surgery
Complications
6 6 26 38
11 12 46 69
0.8; range 0 to 1 2.5; range 2 to 4 3.5; range 1 to 16 2.9 range 0 to 16
1 (BH) 1 (HB) 4 (3HB, 1LMC) 6
*PT-S=Previous proplast-teflon or silastic TMJ implants; HB=heterotopic bone; LMC=loose mandibular component.
alloplastic implants. Group 2 (n=6) included patients with 2 or more previous TMJ surgeries and no previous alloplastic implants. Group 3 (n=26) consisted of patients who had 1 or more previous TMJ surgeries with PT-S placed in the joints. The patients were evaluated clinically by a single investigator, with data recorded on standard forms, for maximum incisal opening, maximum lateral excursions, and occlusal stability at the following intervals: presurgery; postsurgery at 3, 6, 12, 24, 36 months, and at the longest follow-up beyond 5 years. Visual analogue scales (VAS) were used to subjectively evaluate pain levels (0=no pain, 10=worst pain) and jaw function (0=normal function, 10=no function). Functionally, the patients evaluated their ability to chew and perform mandibular movements. Occlusal stability was assessed by cephalometric analysis and by recording the immediate postoperative clinical occlusal relationship and comparing the long-term results relative to Angle’s classification and overbite/ overjet relationships. Descriptive statistics and paired t-tests (P<0.05) were used to compare presurgery and longest postoperative follow-up data. Due to the small sample size, no valid statistical comparison could be used on groups one and two; therefore, all three groups were combined into one group for statistical analysis. Results The patient demographics and pre- and postoperative values of the total group of 38 patients can be seen in Tables 1 and 2. The mean preoperative incisal opening was 27.5 mm (SD 11.1; range 4 to 50 mm) and the mean postoperative incisal opening was 32.6 mm (SD 9.4; range 4 to 56 mm) showing statistically significant improvement at long-term follow-up (P<0.001). The mean preoperative lateral excursive movement was 2.1 mm (SD 2.8; range 0 to 5 mm) with a postoperative mean of 1.7 mm (SD 1.7; range 0 to 3 mm) demonstrating a statistically significant decrease (P<0.04).
The mean subjective VAS preoperative pain level was 7.7 (SD 2.3; range 5.4 to 10) and the mean postoperative pain level was 3.6 (SD 3.1; range 0.5 to 6.7) showing a statistically significant decrease in pain (P<0.0001). The mean preoperative VAS subjective jaw function score was 7.1 (SD 2.3; range 4.8 to 9.4) and the mean postoperative function score was 4.5 (SD 2.3; range 2.2 to 6.8) showing a statistically significant functional improvement (P<0.0001). Long-term occlusion has remained stable in all patients, as compared to the immediate postsurgical occlusal relationship. Some minor tooth positional changes occurred in some patients who were under orthodontic treatment at the time of surgery. Complications encountered included: loosening of one mandibular component, which had only four 2.0 mm diameter titanium screws stabilizing it, in a patient with uncontrolled bruxism, and had to be replaced with a new mandibular component stabilized with 8, 2.0 mm diameter titanium screws. This device has remained stable for over 8 years. Five patients had heterotopic bone formation and required reoperation to remove the bone. In comparing the three groups, we observed that the number of previous TMJ surgeries and exposure to PT-S affected outcomes (Table 3). At the longest follow-up, Group 1 showed greater incisal opening of 39.8 mm (range 27 to 56 mm) and Group 2 had 33.6 mm (range 20 to 45 mm). Although Group 3 had the greatest improvement in incisal
opening (6.3 mm); the group still had the lowest long-term incisal opening at only 30.5 mm (range 4 to 45 mm). The longest follow-up lateral excursion movement was slightly better for Group 1 at 2.3 mm, with Group 2 at 1.5 mm and Group 3 at 1.7 mm, demonstrating a significant reduction for Group 1 and a moderate reduction for Groups 2 and 3. The final average pain level for Group 1 was 1.6 (range 0 to 3), Group 2 was 5.1 (range 0 to 9) and Group 3 was 4.0 (range 0 to 9), where the lower number indicates less pain. The average subjective postoperative jaw function level was better in Group 1 with 3.1 (range 0 to 6) as compared to Group 2 with 4.5 (range 2 to 8) and Group 3 with 4.8 (range 0 to 9), where a lower number indicates better jaw function.
Discussion Techmedica, Inc. developed the TMJ Concepts/Techmedica total joint prosthesis in 1989 as a custom-made TMJ total joint prosthesis. In July 1993, the United States Food and Drug Administration (FDA) halted the manufacture of any TMJ devices developed after 1976, due to lack of safety and efficacy information to support its indicated use. Based on outcomes of this original 5 year study, and the technical merit of design and materials, this product was approved by the FDA to be marketed in July of 1996 by TMJ Concepts Inc. This is the first TMJ total joint device to go through and pass the rigors of FDA
Table 2. Results (38 patients) Mean (SD) Incisal opening Lateral excursion Pain (0=no pain; 10=worst pain) Jaw function (0=normal function; 10=no function)
Preop
Postop
27.5 mm (11) Range 4 to 50 mm 2.1 mm (2.8) Range 0 to 5 mm 7.7 (2.3) Range 5.4 to 10 7.1 (2.3) Range 4.8 to 9.4
32.6 mm (9.4)** Range 4 to 56 mm 1.7 mm (1.7)* Range 0 to 3 mm 3.6 (3.1)** Range 0.5 to 6.7 4.5 (2.3)** Range 2.2 to 6.8
*Statistically significant P<0.05, **statistically significant P<0.001.
24.2 (range 4–40) 30.5 (range 4–45) 2.0 (range 0–11) 1.7 (range 0–3) 7.8 (range 2–10) 4.0 (range 0–9) 7 (range 2–10) 4.8 (range 0–9) 3 Heterotopic bone 1 Loose mandibular component 32.3 (range 12–42) 33.6 (range 20–45) 2.2 (range 0–5) 1.5 (range 0–3) 7.5 (range 5–10) 5.1 (range 0–9) 7.8 (range 5–10) 4.5 (range 2–8) 1 Heterotopic bone *Number of patients.
37 (range 29–50) 39.8 (range 27–56) 4.0 (range 1–8) 2.3 (range 1–3) 7.3 (range 3–9) 1.6 (range 0–3) 7 (range 2–10) 3.1 (range 0–6) 1 Heterotopic bone Incisal opening (mm) Lateral excursion (mm) Pain (0=no pain; 10=worst pain) Jaw function (0=normal function; 10=no function) Complications*
Preop
Group 1 (n=6)
Postop
Preop
Group 2 (n=6)
Postop
Preop
Group 3 (n=26) Postop
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Table 3. Results
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scrutiny. This device uses materials that are well proven in orthopedic joint reconstruction for hip and knee replacements. Although the life expectancy of this device is unknown, based on material selection, treatment philosophy, and this study, these devices have provided the service life of 8 years without evidence of untoward wear or failure. Patients who have received previous TMJ implants, including ProplastTeflon (PT), Silastic (S), or bone cements may have particulization of those materials with migration and penetration into the adjacent bone and soft tissues4,5,7,9,10. It is extremely difficult, if not impossible, to totally remove all of the microscopic particles from the area with surgical debridement. The residual particles can lead to foreign body giant cell reaction that can affect autogenous grafts causing degenerative changes. H & W4 reported a study on 107 patients where autogenous tissues were used to reconstruct the TMJ when previous Proplast-Teflon (PT) had been placed. Long-term evaluations (4 years) for pain, occlusal stability, and jaw function with autogenous grafts for TMJ reconstruction identified the following success rates for each of the tissues used for grafting: Costochondral (12%), sternoclavicular (21%), dermal (8%), temporal fascia (13%), temporal fascia with mandibular sagittal split osteotomies (31%), and auricular cartilage (25%). This study also showed a significant increase in failure rates for all autogenous tissue groups as the number of prior TMJ surgeries increased. After two previous TMJ surgeries, the long term success rate for autogenous tissue grafts approached zero. Ankylosis (decreased function) and pain were the most common causes of failure. Autoimmune, connective tissue, and inflammatory diseases can also attack autogenous grafts in the TMJ area if the joint is involved in the disease process. W et al.12 used sternoclavicular grafts in three different patient types: (1) those with previous PT-S implants, (2) autoimmune, connective tissue, or inflammatory disease processes (i.e. Rheumatoid arthritis, psoriatic arthritis, lupus, Sjogrens, reactive arthritis, spondyloarthropathies), and (3) noninflammatory, non-PT-S TMJ pathology (i.e. previous fractures, congenital deformities). The success rate was 29% in the PT-S joints, 50% in inflammatory disease processes, and 93% in joints with non-inflammatory, non-PT-S pathology. Similar results may occur with other
autogenous grafts when used in joints with previous alloplasts, inflammatory, connective tissue, and autoimmune diseases. In autogenous reconstruction for fibrous or bony ankylosis, the chances of redeveloping heterotopic bone, reactive bone, and/or fibrosis with subsequent reankylosis are very high. The use of a custom-made total joint prosthesis may improve the results in many of these conditions. Patients subjected to multiple (2 or more) surgical procedures will have predictably poorer outcomes compared to those with 0 to 1 previous surgeries, particularly in using autogenous tissues for TMJ reconstruction1,11,13. The more surgeries, the worse the prognosis. Likewise, with total joint prosthesis, the prognosis is worse, particularly related to alleviation of pain11,13. Multiple TMJ operations create scar tissue, interrupt normal blood flow and normal physiologic nutritional distribution to the anatomical structures. This results in degradation of the fibrocartilage, bony structures, articular disc, capsular ligaments, neurogenic components, and associated musculature, that can lead to joint dysfunction, TMJ pain, headaches, myofacial pain, and jaw deformities. Multiple surgeries may establish an environment conducive to a bacterial/ viral reactive arthritis, sympathetic mediated pain, autoimmune polyneuropathy, chronic joint inflammatory disease, etc.11. The high failure rate in using autogenous tissues in the multiply operated TMJ indicates that the custommade total joint prosthesis may be a better alternative for reconstruction of these joints. W et al.13 published a study on 56 patients (55 females, 1 male) with 100 reconstructed temporomandibular joints, using the TMJ Concepts/ Techmedica custom-made total joint prosthesis system. The patients’ average age was 39 years (range 15 to 61 years) and had an average follow-up of 30 months (range 16 to 46 months). The outcomes were categorized as good, fair, or poor, based on clinical and radiographic assessment for pain, incisal opening, and occlusal stability. The results showed that 35 patients (63%) with 58 joints (58%) had a good outcome, 13 patients (23%) with 26 joints (26%) had a fair outcome, and 8 patients (14%) with 16 joints (16%) had a poor outcome. Patients with zero to one previous TMJ surgeries had 86% in the good group, and 16% in the fair group, and no patients in the poor group. In
TMJ concepts total joint prosthesis patients with two or more previous TMJ surgeries, the success rate decreased to 55% with good results, 26% with fair results, and 19% with poor results. Continued pain was the major factor that placed patients in the poor result group which may be related to problems such as cervical neuropathy, residual inflammatory or foreign body giant cell reaction, immunological reaction to alloplastic particles, fibrosis, calcification, heterotopic or reactive bone formation, sympathetic mediated pain, autoimmune polyneuropathy, multiple chemical sensitivity, bacterial/viral contamination, and/or other unidentified factors11. The TMJ Concepts/Techmedica custom-made total joint prosthesis was previously evaluated by H & W4, to determine the outcome in patients with a history of ProplastTeflon TMJ implants. Twenty-six patients (43 joints) were evaluated, with a follow-up from 4 to 24 months. The TMJ Concepts/Techmedica custommade total joint prosthesis provided an 86% success rate relative to stability and function, with a level of residual pain rated as good in 46%, fair 38%, and poor in 16% of the patients. The average postoperative incisal opening in this group was 26 mm at 6 months, 26 mm at 12 months, 32 mm at 18 months, and 35 mm beyond 18 months. M et al.6 published a prospective study on 215 patients (202 females, 13 males) that were reconstructed with the TMJ Concepts/Techmedica total joint prosthesis. The average age at reconstruction was 40.9 years (range 15 to 77 years). There were 363 joints placed, 296 bilateral (148 patients) and 67 unilateral. The patients had TMJ problems for an average of 10.7 years (range 1 to 44 years) prior to surgery, and had undergone a mean of 5.4 (range 0 to 28) prior unsuccessful surgeries. Preoperative and postoperative data were collected for up to 48 months, using a standardized collection format. The results showed statistically significant changes in subjective evaluations including decrease in pain, increase in jaw function, and improvement in diet (P<0.0001). There was also an improvement in incisal opening. The number of previous surgeries was a strong predictor of postoperative pain, function, and diet scores, as well as maximal incisal opening, with an increased number of previous surgeries resulting in poorer outcomes. A lifetime table analysis was performed, indicating good durability of the prosthesis over time. The study
demonstrated that the TMJ Concepts/ Techmedica custom-made total joint prosthesis was useful in the treatment of multiply operated and anatomically mutilated TMJ patients. Five of the TMJ patients in this study have required additional TMJ surgical procedures, following reconstruction with the total joint prosthesis, for removal of fibrotic tissue, continued foreign body giant cell reactions secondary to Proplast-Teflon and Silastic implants, and/or removal of heterotopic and reactive bone. In the surgical re-examining of these joints, there was no visual evidence of wear or cracking of the UHMWPE surface or the chromium-cobalt-molybdenum condylar head. The longest postsurgery time for patient evaluation in this manner was 8.2 years. Histological evaluation of intercapsular tissues taken from those patients with no previous PT-S TMJ implants, showed no evidence of wear debris or foreign body giant cell reaction, confirming the high quality wear characteristics of the prosthesis. In this present study, lateral excursion movements decreased in all three groups. This decrease was likely due to required condylectomy, detachment of the lateral pterygoid muscle to remove the condyle, and subsequent fibrosis and heterotopic/reactive bone that can form around the TMJ prostheses. In approximately 60% of the patients in this study, the lateral pterygoid muscle was reattached to the neck of the prosthesis by permanent sutures, but this did not appreciably improve excursive movements. A common problem with TMJ prostheses is the development of fibrosis and reactive/heterotopic bone around the prostheses, causing pain and limited jaw function. In patients with previous PT-S TMJ implants, the foreign body giant cell reaction can continue because the particulated materials cannot be completely removed. W & K14 have reported a technique of placing a fat graft (harvested from the abdomen or the buttocks) around the TMJ total joint prosthesis to eliminate the dead space. Eliminating the dead space prevents blood clot formation, which otherwise could provide a matrix for the fibrous ingrowth and pluri potential cells migrating into the area that could develop bony and dense fibrous tissues. Also, in patients with previous alloplastic implants, the fat graft blocks out a large area in which foreign body giant cell reaction may otherwise
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redevelop. None of the patients in the study presented herein, had fat grafts placed around the prostheses at the time of TMJ total joint reconstruction, as advocated by some authors8,14, nor was any radiation therapy utilized to inhibit heterotopic bone formation as recommended by others2,3, W & K14 reported on 15 consecutive patients (22 joints) with TMJ Concepts/ Techmedica total joint prostheses, where fat grafts were packed around the joint area and compared the outcomes with 20 consecutive patients (37 joints) treated prior to initiation of the fat graft technique. The patients with fat grafts had improved incisal opening and excursive movements, as well as some decrease in pain. In addition, none of the patients receiving the fat grafts had to be taken back to surgery for removal of fibrous tissue or heterotopic bone as compared to about 30% of the non-grafted group. This technique demonstrates a major improvement in the outcome of patients requiring TMJ total joint prosthesis reconstruction. Two patients had a biopsy of their fat grafts, one at 4 months, and one at 12 months, showing good viability of the fat tissues14. This study demonstrates that the TMJ Concepts/Techmedica total joint prosthesis works well long-term (5 to 8 years of follow-up), and is a viable technique for TMJ reconstruction, as a primary procedure when indicated, and for patients with previous multiple TMJ surgeries and mutilated anatomy of the TMJ.
References 1. B JP, I AT. Failure Rates of Repetitive Temporomandibular Joint Surgical Procedures. Presented at the American Association of Oral and Maxillofacial Surgeons 74th Annual Meeting. Scientific Poster Session III held in Honolulu, Hawaii. September 1992 (abstract). J Oral Maxillofac Surg 1992: 50: 145. 2. D ED, T EG. Radiation treatment of heterotopic bone formation in the temporomandibular joint articulation. Int J Radiol Oncol Phys 1993: 27: 863–869. 3. F RJ, A AQ. Single dose 6 Gy prophylaxis for heterotopic ossification after total hip arthroplasty. Clin Orth 1995: 317: 131–140. 4. H CH, W LM. Treatment outcomes for temporomandibular joint reconstruction after proplast-teflon implant failure. J Oral Maxillofac Surg 1993: 51: 352–358.
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5. J M, S E. Wear particles of total joint replacements and their role in periprosthetic osteolysis. Curr Opinion Rheumatol 1992: 4: 204–209. 6. M LG, W LM, S B, W RD, H A, H W. Custom CAD/CAM total temporomandibular joint reconstruction system: Preliminary report. J Oral Maxillofac Surg 1995: 53: 106–115. 7. S M. Biomaterial failure. Orthop Clin North Am 1992: 12: 211–217. 8. T BJ. Heterotopic bone formation after total hip arthroplasty. Orthop Clin North Am 1992: 23: 347–358. 9. W PS, B PG. The effects of friction and wear in artificial joints. Orthop Clin North Am 1973: 4: 275–293.
10. W DF. Tissue reaction to metallic corrosion products and wear particles in clinical orthopedics. In: Williams DF, ed.: Biocompatibility of Orthopedic Implants. Vol I: Boca Raton, FL: CRC 1982: 231–248. 11. W LM. Temporomandibular joint devices: treatment factors and outcomes. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997: 83: 143–149. 12. W LM, C DA, H CH. Sternoclavicular grafts for TMJ reconstruction. J Oral Maxillofac Surg 1994: 52: 119–128. 13. W LM, C DA, H CH. Temporomandibular joint reconstruction of the complex patient with the techmedica custom-made total joint
prosthesis. J Oral Maxillofac Surg 1994: 52: 2–10. 14. W LM, K SC. Autologous fat transplantation around TMJ total joint prosthesis: preliminary treatment outcomes. J Oral Maxillofac Surg 1997: 55: 245–251. Address: Larry M. Wolford 3409 Worth St. Suite #400 Dallas TX 75246 USA Tel: (214) 828-9115 Fax: (214) 828-1714 E-mail: [email protected]