Acute pain after total hip arthroplasty does not predict the development of chronic postsurgical pain 6 months later

Much remains unknown about the relationship between acute postoperative pain and the development of pathologic chronic postsurgical pain (CPSP). The purpose of this project was to identify the extent to which maximum pain scores on movement over the first two days after total hip arthroplasty predicted the presence of chronic pain 6 months later after controlling for potentially important covariates.

The sample comprised 82 of 114 patients who participated in a double-blinded randomized controlled trial in which all patients received acetaminophen 1 g p.o., celecoxib 400 mg p.o., and dexamethasone 8 mg i.v., 1-2 h preoperatively. In addition, patients received gabapentin (GBP) 600 mg (G2) or placebo (G1 and G3) 2 h prior to surgery [G1: placebo/placebo (n = 38); G2: GBP/placebo (n = 38); G3: placebo/GBP (n = 38)]. In the PACU, patients received gabapentin 600 mg (G3) or placebo (G1 and G2). Follow-up data from the 82 patients who were contacted by telephone 6 months postsurgery were used for the current study.

Maximal movement-evoked pain intensity over the first two postoperative days (P = 0.38) failed to predict the presence of CPSP 6 months later after controlling for age (P = 0.09), treatment group (P = 0.91), and cumulative morphine consumption (P = 0.8) (multivariate logistic regression likelihood ratio test against the intercept only model P = 0.59).

Neither maximum movement-evoked acute pain, nor any other factor measured, predicted the presence of CPSP at 6 months. Further research is needed to identify risk factors for CPSP after total hip arthroplasty.