Efficacy of Intravenous Acetaminophen for Postoperative Analgesia in Primary Total Knee Arthroplasty.

BACKGROUND: The use of intravenous acetaminophen has seen recent enthusiasm as one component of a multimodal approach to pain management. However, there is a lack of literature examining the efficacy of intravenous acetaminophen for pain control in total joint arthroplasty. The purpose of this study was to evaluate the efficacy of intravenous acetaminophen following primary total knee arthroplasty. METHODS: This is a retrospective review of 38 patients undergoing primary total knee arthroplasty by a single surgeon at one institution. Twenty-five patients received 1 gram of intravenous acetaminophen every 6 hours for 24 hours postoperatively. Thirteen patients received no additional intervention. Exclusion criteria were bilateral or concomitant procedures, allergy to medications included in the standard postoperative protocol, neuropathy or sensory disturbances, history of opioid dependence or abuse, deviations from protocol, revision procedures, and incomplete data. Primary outcomes were change in patient-reported visual analog scale (VAS) pain score, overall opioid consumption measured in morphine milligram equivalents, and hospital length of stay. RESULTS: We found no difference in length of stay, at 3.3 days in the control group and 2.9 days in the intervention group. There was a significant difference in VAS score between 16 and 24 hours. There was a statistically significant decrease in overall opioid consumption in the intravenous acetaminophen group 37.6 vs 18.6 morphine milligram equivalents. CONCLUSION: Intravenous acetaminophen is effective in significantly reducing opioid requirements in the first 24 hours following primary total knee arthroplasty. Additionally, there is a clinically significant decrease in VAS pain scores in patients receiving this intervention.

Prevalence and predictors of osteoporosis risk in orthopaedic patients.

BACKGROUND: Current physician practices are not effective in adequately evaluating and treating patients for osteoporosis. While dual-energy xray absorptiometry is the gold standard in evaluating bone mineral density, calcaneal quantitative ultrasound has emerged as a low-risk and low-cost alternative. QUESTIONS/PURPOSES: We estimated the prevalence of abnormal bone mineral density with calcaneal quantitative ultrasound and developed criteria for risk stratification in female and male orthopaedic patients. METHODS: We enrolled 500 patients (331 women, 169 men) with a mean age of 67 years (range, 55-94 years) and screened them for osteoporosis with calcaneal quantitative ultrasound. Multivariate logistic regression was used to identify predictors of low bone mineral density and a risk model was developed. RESULTS: Quantitative ultrasound identified 154 patients with low bone mineral density at the time of enrollment. The prevalence of abnormal bone mineral density was 31% (women: 38%, men: 17%). Multivariate analysis demonstrated age, female gender, smoking, wrist fracture, and spinal deformities independently predicted low bone mineral density. The probability of low bone mineral density among patients with more than one risk factor was greater than 50% among women and greater than 30% among men. CONCLUSIONS: Low bone mineral density is common among orthopaedic outpatients. Age, female gender, smoking, wrist fractures, and spinal deformities are independent risk factors for osteoporosis. We present a probability model designed to assist orthopaedic surgeons in identifying high-risk patients and initiating adequate preventative measures. LEVEL OF EVIDENCE: Level I, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.