Postoperative Pain Control by Local Infiltration Analgesia and Peripheral Nerve Block in Primary Prosthetic Total Knee Arthroplasty

BACKGROUND AND OBJECTIVE: Postoperative (post-op) pain control has an important impact on post-op rehabilitation. The logistics of its maintenance challenge the effect of peripheral nerve block on post-op pain control, with the risk for post-op complications. We hypothesized that perioperative use of local infiltration analgesia (LIA) is comparable to post-op pain control by peripheral nerve block. MATERIALS AND METHODS: We evaluated three groups of patients treated with primary total knee arthroplasty (TKA) due to symptomatic end-stage osteoarthritis with post-op pain control by LIA (LIA group, n=52), femoral plus sciatic nerve block (FSNB) (FSNB group, n=54), and without local or regional analgesia as controls (Control group, n=53). The primary outcome variable was the post-op pain level intensity as measured by the visual analog scale (VAS). Secondary outcome variables were knee function measured by the Knee Society Score (KSS) and the quadriceps muscle strength recovery profile. RESULTS: Up to 4 hours post-op, pain intensity was significantly lower in FSNB patients (P<0.05). This effect of the peripheral nerve block on the pain level disappeared 6 hours post-op. The LIA and FSNB patients showed a significant decrease in pain intensity on days 2 and 3 post-op (P<0.05) with no mutual differences (P>0.05). This effect disappeared on day 4 post-op (P>0.05). The KSS score showed similar significant improvement of functional abilities (P<0.001) in all three groups. There was no difference in KSS scores among the groups 6 months after surgery (P>0.05). Quadriceps muscle recovery profile was similar in the LIA and Control groups, but significantly poorer in the FSNB group (P<0.001). CONCLUSION: The value of very short-term and improved pain relief of post-op FSNB over LIA of the surgical wound should be carefully weighed against its cost, logistics, and potential complication threat.