Predictive risk factors for persistent pain following total prosthetic temporomandibular joint replacement.

The aim of this study was to determine the rate of persistent pain following total TMJ replacement and to identify potential predictive risk factors. A retrospective review of case notes treated by a single surgeon in a tertiary unit was performed. For each patient a number of variables were recorded including visual analogue pain scores (0 to 10) and opioid usage pre surgery and at 12 months or last follow up beyond 12 months. Persistent pain scores of 5 to 7 were regarded as moderate and 8 to 10 as severe. The mean pain score at last follow-up was significantly lower than preoperatively (2.1 vs. 6.3, p < 0.001) with a mean follow-up time of 40.1 months (range 12-44). 16.4% of the patients reported moderate to severe pain and 13.7% were still on regular opioids at the last follow-up. Therefore 15 patients (20.5%) suffered from chronic postoperative pain after TMJ replacement surgery. Patients reporting severe preoperative pain scores (p = 0.04), regular opioid use (p = 0.001) or multiple previous open TMJ surgeries (p = 0.03) were more likely to suffer from chronic persistent pain and these should be regarded as predictive risk factors. The identification of these factors allows for better risk stratification of patients, informed consent and the agreement of expected outcomes. Patients with true articular disease and a single failed surgery should be considered for early total TMJ replacement to minimise multifactorial persistent pain.