Study evaluates Different Pain Management Approaches After Knee Replacement Surgery
Partial knee replacement
When patients have knee replacement surgery, managing pain afterward is crucial for helping them recover well and start moving around quickly. Recently published study compared two different methods of blocking pain signals using nerve blocks—specialized injections that prevent pain signals from reaching the brain.
The Two Approaches Being Compared
The first method, called ACB combined with iPACK, involves two separate injections that target specific nerves around the knee. The adductor canal block (ACB) targets a nerve in the inner thigh, while iPACK targets small nerve branches on the back of the knee. The second method, combining sciatic and femoral nerve blocks (S + F), targets two larger nerves—one in the back of the thigh and one in the front.
Key Differences in How They Work
The main advantage of the ACB + iPACK approach is that it provides excellent pain relief while preserving the patient's ability to move their leg muscles. In contrast, the S + F method is very effective at blocking pain but tends to weaken the thigh muscles temporarily, which can slow down recovery.
What the Study Found
Researchers looked at 126 patients who received one of these two pain management techniques. They measured pain levels, how much opioid medication patients needed, how well patients could bend their knees, and how soon patients could walk.
The results showed that the ACB + iPACK group had better overall outcomes. These patients experienced less pain, especially when moving around, and required fewer opioid medications over the first two days after surgery. They could also bend their knees more effectively and started walking about nine hours sooner than the S + F group.
Perhaps most importantly, the ACB + iPACK group had much less leg weakness, with about 95% of patients experiencing no muscle weakness at all, compared to only 18% in the S + F group.
Why This Matters
For patients recovering from knee replacement, the ability to move and exercise early is extremely important. It prevents stiffness, improves overall function, and reduces complications like blood clots. The ACB + iPACK method appears to offer a better balance—providing strong pain relief while keeping muscles strong enough for early rehabilitation. This means patients can start their physical therapy exercises sooner and potentially go home faster, leading to better long-term outcomes and greater patient satisfaction.
Key Points
- Total knee arthroplasty (TKA) is a common surgery for knee conditions like osteoarthritis, and postoperative rehabilitation is crucial for restoring knee function and mobility.
- Nerve blocks, such as femoral and sciatic nerve blocks, are vital for postoperative pain management and rehabilitation in TKA patients.
- A retrospective study in Taiwan compared adductor canal block (ACB) combined with iPACK block to sciatic and femoral nerve blocks in TKA patients, showing that the ACB with iPACK block regimen had superior analgesic efficacy and motor recovery.
- Results indicated that the ACB with iPACK block group had lower pain scores, decreased opioid consumption, reduced motor blockade, faster functional recovery, and improved early ambulation compared to the sciatic and femoral nerve block group.
- The study findings consistently demonstrated that the ACB with iPACK block regimen offered better pain control, lower opioid use, improved motor function, and earlier ambulation postoperatively.
- Despite limitations such as its retrospective nature, small sample size, and potential biases, the study supports the effectiveness of ACB combined with iPACK block as a superior nerve block regimen for TKA patients, highlighting its benefits in pain management and rehabilitation outcomes.
Reference -
Sung CH, Liu JH, Hung CF, Fu CH. Comparative analysis of adductor canal block combined with iPACK block versus femoral combined with sciatic nerve blocks: a propensity score matched study. BMC Anesthesiol. 2025 May 16;25(1):249. doi: 10.1186/s12871-025-03112-z. PMID: 40380131; PMCID: PMC12083146.
