Preoperative dexamethasone for pain relief after total knee arthroplasty A randomised controlled trial

BACKGROUND Corticosteroids can reduce pain but the optimal dose and safety profiles are still uncertain. OBJECTIVE This study aimed to evaluate two different doses of dexamethasone for pain management and their side effects after total knee arthroplasty. DESIGN A prospective randomised, controlled trial. SETTING A tertiary teaching hospital in Hong Kong. PATIENTS One hundred and forty-six patients were randomly allocated to one of three study groups. INTERVENTIONS Before operation, patients in group D8, D16 and P received dexamethasone 8 mg, dexamethasone 16 mg and placebo (0.9% saline), respectively. MAIN OUTCOME MEASURES The primary outcome was postoperative pain score. Secondary outcomes were opioid consumption, physical parameters of the knees and side effects of dexamethasone. RESULTS Compared with placebo, group D16 patients had significantly less pain during maximal active flexion on postoperative day 3 [-1.3 (95% CI, -2.2 to -0.31), P = 0.005]. There was also a significant dose-dependent trend between pain scores and dexamethasone dose (P = 0.002). Compared with placebo, patients in group D16 consumed significantly less opioid [-6.4 mg (95% CI, -11.6 to -1.2), P = 0.025] and had stronger quadriceps power on the first three postoperative days (all P < 0.05). They also had significantly longer walking distance on postoperative day 1 [7.8 m ([95% CI, 0.85 to 14.7), P = 0.023] with less assistance during walking on the first two postoperative days (all P < 0.029) and significantly better quality-of-recovery scores on postoperative day 1 (P = 0.018). There were significant dose-dependent trends between all the above parameters and dexamethasone dose (all P < 0.05). No significant differences were found in the incidence of chronic pain or knee function 3, 6 and 12 months postoperatively. CONCLUSION Dexamethasone 16 mg given before total knee arthroplasty led to a reduction in postoperative pain, less opioid consumption, stronger quadriceps muscle power, better mobilisation and better overall quality-of-recovery after operation. No long-term improvement in reduction in pain and function of the knee was found.