Abstract
The purpose of this study was to assess the number of alloplastic total temporomandibular joint replacement (TMJ TJR) devices implanted and the complications encountered by members of the American Society of Temporomandibular Joint Surgeons (ASTMJS). A questionnaire was developed using REDCap (Chicago, IL) and an on-line link was e-mailed four times over a 6-week period (February to March 2015) to all members of the ASTMJS. The questionnaire included eight questions related to the surgeon’s TMJ TJR experience. A Likert scale was included to assess the respondents’ opinions concerning the future demand for TMJ TJR and their thoughts on potential device improvements. The study sample was composed of 36 ASTMJS respondents (42.4%). TMJ TJR is performed successfully and in relatively high numbers by members of the American Society of Temporomandibular Joint Surgeons.
Since its introduction by Sir John Charnley, orthopedic surgeons have been successfully employing alloplastic total joint replacement for the management of end-stage joint pathology for over five decades. Alloplastic total temporomandibular joint replacement (TMJ TJR) has been documented to be a safe and effective option for the management of end-stage temporomandibular joint (TMJ) pathology in worldwide studies for over two decades.
A prior study assessed the current level of experience that oral and maxillofacial surgery residents in the USA attain in TMJ TJR during training. This study reported that despite variable program experience, it appeared that adequate TMJ TJR didactic and clinical training was being provided to residents. However, it was felt by the respondents that a study was needed to demonstrate the actual utilization of the TMJ TJR training after completion of residency and during the clinical practice of oral and maxillofacial surgery.
The American Society of Temporomandibular Joint Surgeons (ASTMJS) is a non-profit organization whose objective is to stimulate the interest of health care specialists and the public in a more exact knowledge and improved practice of the science and art of rehabilitation of persons with TMJ disorders. Active membership in this organization is achieved by credentialing of surgical experience in the management of TMJ disorders. An international membership classification includes experienced TMJ surgeons from around the world.
This study was performed as a follow-up to the previous study, in order to assess the number of TMJ TJR devices implanted and the complications encountered in a private practice setting. Since members of the ASTMJS perform TMJ surgery on a regular basis, it was decided to survey this group of surgeons to acquire the data for the study. These data, along with the data from the prior academic study, will provide important information on the number of TMJ TJR procedures performed as well as the most commonly encountered TMJ TJR complications.
Materials and methods
A questionnaire was developed using REDCap (Chicago, IL). The on-line link to that questionnaire was emailed four times over a 6-week period (February to March 2015) to all members of the ASTMJS. The questionnaire included eight questions aimed to elicit the desired information on the respondent surgeons’ TMJ TJR experience between 2005 and 2014.
The respondents were de-identified in the survey tool, but the country of practice was noted. After 6 weeks, the results were analyzed using the charts and graphs created in REDCap, as well as tables created from the dataset.
The study was approved by the necessary institutional review board.
Results
All 85 ASTMJS members were solicited and 36 responded (42.4%). Of the respondents, 20 were from the USA, four from Australia, and two from the UK, and one response was obtained from each of Brazil, Canada, Japan, New Zealand, Denmark, the Netherlands, and Spain; three respondents did not report their country. Fig. 1 demonstrates the average number of TMJ TJR cases the responding surgeons performed per year between 2005 and 2014.
TMJ Inc. (Golden, CO) (aka TMJ Medical (Golden, CO), aka Nexus CMF (Salt Lake City, UT)) provided stock metal-on-metal implants to only two of the responding surgeons. TMJ Concepts (Ventura, CA) provided patient-fitted metal-on-ultrahigh molecular weight polyethylene (UHMWPE) implants for 69.4% of the surgeons, and Biomet Microfixation (Jacksonville, FL) provided stock metal-on- UHMWPE implants for 55.6% of the surgeons. Promm (Porto Alegre, RS, Brazil), KLS Martin (Groningen, Netherlands), and Bütow (Pretoria, South Africa) each provided one device over the study period.
To calculate the TMJ TJR failure rate of the respondents over the past 10 years, two numbers were generated. As a result of the survey responses being a range (i.e., 1–2, 3–4, etc.), two failure rates were calculated, the first using the minimum number of failures and the minimum number of procedures and the second using the maximum number of failures and the maximum number of procedures. The failure rate was 4.97% and 8.22%, respectively. Careful consideration must be given prior to assessing the failure rate value of 8.22% in this study, as many respondents selected the answer choice ‘>10 procedures’. However, since a concrete number was not given, the estimated number of TMJ TJR procedures was underestimated, thereby artificially increasing the complication percentage rate. The reported causes of these failures and intraoperative complications are shown in Figs 2 and 3 . These are reported as the percentage of cases encountered during surgery and in the follow-up period by the responding surgeon.
In this study, 30 of the 36 of the respondents (83.3%) agreed or strongly agreed with the statement: “There will be an increase in demand for alloplastic TMJ TJR in the future.”
When asked their opinions on the improvement of future alloplastic TMJ TJR, the majority of respondents felt that improvements in 3D surgical planning and surgeon training are necessary and 12 (33.3%) felt that improved materials and surgical navigation would enhance outcomes.
Regarding the lifespan of the TMJ TJR devices, the overwhelming majority of surgeons (94.4%) expected the TMJ TJR devices to last 10 years or more ( Fig. 4 ). Twenty-five respondents (69.4%) felt that TMJ TJR devices have an expected functional longevity of 11–20 years, while nine respondents (25%) felt they could possibly function for the life expectancy of the patient.
