Predictors for moderate to severe acute postoperative pain after total hip and knee replacement.

PURPOSE: The ability to identify and focus care to patients at higher risk of moderate to severe postoperative pain should improve analgesia and patient satisfaction, and may affect reimbursement. We undertook this multi-centre cross-sectional study to identify preoperative risk factors for moderate to severe pain after total hip (THR) and knee (TKR) replacement. METHODS: A total of 897 patients were identified from electronic medical records. Preoperative information and anaesthetic technique was gained by retrospective chart review. The primary outcomes were moderate to severe pain (pain score ≥ 4/10) at rest and with activity on postoperative day one. Logistic regression was performed to identify predictors for moderate to severe pain. RESULTS: Moderate to severe pain was reported by 20 % at rest and 33 % with activity. Predictors for pain at rest were female gender (OR 1.10 with 95 % CI 1.01-1.20), younger age (0.96, 0.94-0.99), increased BMI (1.02, 1.01-1.03), TKR vs. THR (3.21, 2.73-3.78), increased severity of preoperative pain at the surgical site (1.15, 1.03-1.30), preoperative use of opioids (1.63, 1.32-2.01), and general anaesthesia (8.51, 2.13-33.98). Predictors for pain with activity were TKR vs. THR (1.42, 1.28-1.57), increased severity of preoperative pain at the surgical site (1.11, 1.04-1.19), general anaesthesia (9.02, 3.68-22.07), preoperative use of anti-convulsants (1.78, 1.32-2.40) and anti-depressants (1.50, 1.08-2.80), and prior surgery at the surgical site (1.28, 1.05-1.57). CONCLUSIONS: Our findings provide clinical guidance for preoperative stratification of patients for more intensive management potentially including education, nursing staffing, and referral to specialised pain management.

A cross-sectional survey on prevalence and risk factors for persistent postsurgical pain 1 year after total hip and knee replacement.

BACKGROUND AND OBJECTIVES: There is a paucity of large multi-institutional surveys to determine the prevalence of and risk factors for persistent pain after total hip (THR) and knee (TKR) replacements. We surveyed a variety of practices and patients and also correlated persistent pain with health-related quality-of-life outcomes. METHODS: From October 10, 2007, to March 15, 2010, patients who had undergone primary THR or TKR with a minimum follow-up of 1 year were identified. A previously published questionnaire to identify persistent postsurgical pain that included a 36-item Short Form Health Survey was mailed to this group. Independent risk factors for persistent pain were identified with logistic regression. RESULTS: Responses from 1030 patients who underwent surgery at some point in time between June 13, 2006, and June 24, 2009, were analyzed (32% response rate). Forty-six percent of patients reported persistent pain (38% after THR and 53% after TKR) with a median average pain score of 3 of 10 and worst pain score of 5. Independent risk factors for persistent pain were female sex (odds ratio [OR], 1.23), younger age (OR, 0.97), prior surgery on hip or knee (OR, 1.39), knee versus hip replacement (OR, 1.65), lower-quality postsurgical pain control (OR, 0.9), and presence of pain in other areas of the body (OR, 2.09). All scores in the 36-item Short Form Health Survey were worse (8%-28% decrease) in patients with persistent postsurgical pain (P < 0.001). CONCLUSIONS: Persistent postsurgical pain is common after THR and TKR and is associated with reduced health-related quality of life, although our survey may be biased by the low response rate and retrospective recall bias. Nonmodifiable risk factors may lead to risk stratification. Severity of acute postoperative pain may be a modifiable risk factor.