gms | German Medical Science

Objectives: In recent years, there has been an increasing interest in local infiltration analgesia (LIA) as a technique to control postoperative pain. We compared this technique to the gold standard using the 3 in 1 nerve block in postoperative pain management after total knee arthroplasty (TKA). This trial analyzed pain, range of motion and consumption of pain medications after TKA in the early postoperative phase.

Methods: We conducted a retrospective trial by analyzing the data of 202 patients, which were separated in two groups. Group 1 treated by 3-in-1 femoral nerve block included 102 patients whereas 105 patients were treated by LIA. The demographic data, as well as the American Society of Anesthesiologists-Score (ASA-Score) were collected. The pain intensity was measured objectively with a numeric rating scale (NRS) in the morning and evening. The pain medication was given according to two protocols with a fix opioid dose for the first 3 days only, additional pain medication could be requested by the patient at any time. Not only the dosage but also the number of additional pain medication was observed. The range of motion was measured from the second postoperative day.

Results: This study showed no statistical difference between the two groups regarding sex, operated side and ASA-score. The pain intensity showed statistical difference between the groups, with the LIA group showing a lower pain intensity in the early postoperative phase, especially in the first days and in the morning. On the 1st postoperative day the average of numeric pain scale for the nerve block group was 2,2 (SD = 1,5) , which was significant higher than the average of the LIA group 1,4 (SD = 1,1). The measurements in the evening show that during the first seven postoperative days there was no significant difference for the pain intensity. The average dose of Oxycodon received on the first postoperative day was 18,8mg (SD = 9,1) in the nerve block group and 11,5mg (SD = 6,2) in the LIA group, on the 6th day the dosage received was 11,9mg (SD = 11,3) respectively 6,2mg (SD = 7,3). On the first postoperative day 50% of the nerve block group received no additional non-opioid medication, 37% received one additional and 13% received two additional non-opioid medication. In the LIA group 68% received no additional medication, 31% received one additional and only 1% received two additional non-opioid medication. And finally the LIA group showed a statistical better range of motion of the operated knee in the early postoperative phase, on the 2nd day 48° + 10 versus 36° + 7 with p = 0,000 and on 7th day 79° + 14 versus 71° + 12 with p = 0,016.

Conclusion: The LIA group showed in this study a significant lower consumption dose of opioid and a quicker recovery of range of motion then the 3 in1 nerve block group. Furthermore additional pain medication could be reduced during the hospital stay.

Level of evidence: retrospective trial