Ultrasound guided femoral nerve block and lateral femoral cutaneous nerve block for postoperative pain control after primary hip arthroplasty: a retrospective study.

PURPOSE: The purpose of this study was to evaluate the use of an ultrasound guided femoral nerve (FN) block together with an ultrasound guided lateral femoral cutaneous nerve (LFCN) block in addition to a patient controlled intravenous analgesia (PCIA) pump with piritramide as a strategy for postoperative pain-management after primary hip arthroplasty.

METHODS: In a retrospective study, data recorded from 32 patients undergoing primary hip arthroplasty in 2008, before peripheral blocks were used, were compared with data from 38 patients undergoing primary hip arthroplasty in 2011, when an ultrasound guided single shot FN and LFCN block was used. As primary endpoint the total piritramide consumption after 48 hours was analyzed. A score on a visual analog pain scale at rest and during movement was included as a secondary outcome.

RESULTS: Patients receiving the peripheral nerve blocks used significantly less piritramide in comparison to the patients who received no peripheral nerve blocks (p < 0.01). Moreover, pain scores at rest and during movement were significantly lower in the group with the peripheral nerve block (p-values respectively < 0.01 and < 0.05).

CONCLUSIONS: This retrospective study indicates that a FN block in combination with a LFCN block as supplementary postoperative analgesia after primary hip arthroplasty, can reduce the piritramide consumption. Furthermore, patients receiving the peripheral nerve block report lower pain scores at rest and during movement compared with the patients who did not receive a peripheral block. However, as this is a retrospective study, conclusions have to be drawn cautiously.