Background
The surgery of knee arthroplasty produces intense postoperative pain and its management is still a challenge.
The aim of the study is to evaluate the analgesic efficacy and safety of sublingual sufentanil in the postoperative of total knee arthroplasty.

Methods
The study prospectively compares a group of patients who underwent knee replacement and received postoperative femoral block and sublingual sufentanil by Zalviso system (n = 31) versus a historical cohort of patients (n = 33) operated of knee arthroplasty who have received double block femoral + sciatic and rescues of subcutaneous methadone.

Results
Patients of both groups are comparable in age, comorbidities and type of surgery.
In both groups of patients, the mean VAS corresponded to controlled pain.
In the Zalviso group we found 8 patients with adverse effects (25%). Nausea and vomiting in 1 (3.2%). Dizziness in 3 (9.6%). Constipation in 3 (9.6%). Insufficient analgesia in 1 (3.2%) Disorientation in 2 (6.45%)
In the control group, 8 patients (24%) presented adverse effects. Pain in 2 (6%). Constipation in 3 (9%). Intolerance to methadone 1 (3%) and disorientation in 2 (6%)
Regarding the hospital stay, the difference has not been statistically significant.
The patients at the end of their hospital stay evaluated the satisfaction with the analgesic technique used on a scale of 1 to 10. The Zalviso group obtained the score (8.61 vs. 6.82, p = 0.000).
Conclusion:
 Sublingual sufentanil in Zalviso device is an option for pain control in the postoperative period of total knee arthroplasty

SUBLINGUAL SUFENTANIL IN ZALVISO SYSTEM FOR KNEE ARTHROPLASTY IN OUR EXPERIENCE. PRELIMINARY RESULTS