The Pericapsular Nerve Group (PENG) Block Combined With Local Infiltration Analgesia (LIA) Compared to Placebo and LIA in Hip Arthroplasty Surgery

A Multi-center Double-blinded Randomized-controlled Trial

D.-Yin Lin; Brigid Brown; Craig Morrison; Nikolai S. Fraser; Cheryl S. L. Chooi; Matthew G. Cehic; David H. McLeod; Michael D. Henningsen; Nikolina Sladojevic; Hidde M. Kroon; Ruurd L. Jaarsma


BMC Anesthesiol. 2022;22(252) 

In This Article


During the study period, 75 patients were admitted for elective THA and screened for eligibility. Seven patients were excluded on the basis of cognitive impairment or a language barrier. Eight patients declined to participate, due to a preference for general anesthesia instead of the standardized spinal anesthesia, leaving 60 patients who were consented and randomized equally between both groups. (Figure 1) All patients completed the study and were included in the final intention to treat analysis without loss to follow up.

Figure 1.

CONSORT flow diagram

The preoperative demographics of both groups were similar, including baseline NRS pain scores, pain catastrophising scores, incidence of chronic pain and anxiety or depression. (Table 1).

Primary Outcome

Day 0 pain scores in PENG block patients were significantly lower than in the sham block group: 14 patients (47%) in the PENG group reported no pain, compared to 6 patients (20%) in the sham group (p = 0.03). In both groups, 14 patients (47%) reported mild pain, and 2 patients (6%) in the PENG group experienced moderate or severe pain, compared to 10 patients (33%) in the sham group. (Table 2) These pain scores were maximum and on mobilisation, as quadriceps strength was tested immediately prior.

Secondary Outcomes

On Day 1, pain scores were similar between both groups (p = 0.82). Quadriceps muscle strength was preserved in the PENG group and was similar when compared to the sham block group on Day 0 (p = 0.24) and Day 1 (p = 0.75): On Day 0, 23 (77%) PENG patients and 24 (80%) sham block patients had intact quadriceps muscle strength (p = 0.24), and on Day 1 this was 24 (80%) and 22 (73%) respectively (p = 0.75). (Table 2).

Complication rates were similar between both groups. One patient in the sham group had uncontrolled postoperative pain on the ward, requiring maximalisation of oral analgesia, commencement of a fentanyl patient-controlled analgesia pump, and at the end of Day 1 placement of a PENG block. (Table 3). These measures were largely effective. This patient was regarded as a sham patient as per intention-to-treat, and the primary and most secondary outcome measures had already been collected.

There were no differences in PROMs, Timed Up-and-Go tests, patient satisfaction, time to first mobilization, time to discharge and postoperative opiate use between groups. (Table 4 and Table 5).

Adverse Events and Protocol Deviations

In two patients, one in each group, it was technically not possible to perform a spinal anaesthesia. Both had multiple failed attempts at locating a vertebral interspace for neuraxial injection. Therefore, both received a general anaesthetic for surgery.