b. **Local infiltration analgesia (LIA)**:

Kohan and Kerr repopularized the concept of local infiltration analgesia (LIA) in 2008 for postoperative analgesia for knee surgery [55]. It is mainly given by the operating surgeon during surgery using various drug combinations and volumes. The cocktail combination used for LIA includes LA (ropivacaine 2 mg/ml or bupivacaine 2.5 mg/kg), NSAIDs (ketorolac 30 mg), adrenaline (10 micrograms/ml), opioids (morphine 5–10 mg), and steroids (dexamethasone 8 mg). The total volume of cocktail combination used for LIA may go up to 100–170 ml. For LIA, the surgeon mainly targets the anterior and posterior capsule of the knee, intercondylar area, collateral ligaments, tissue along the femur and tibia, and subcutaneous tissue.

The analgesic effect of the LIA technique depends on the involved injection sites by the surgeon and used drug combinations. However, the drawbacks of single-shot LIA include its limited duration of analgesia (12–18 hours), chances of infection if sterility is not maintained while loading drugs [56, 57], and chondrotoxicity [58] (due to agents used) that may cause loosening of the implants in the long-term followups. Indwelling LIA catheter is usually avoided due to the fear of infection.

### c. **Ultrasound-guided Ring block**:

Ultrasound-guided Ring block is nothing but the LIA technique given by an anesthesiologist under direct vision using ultrasound

*Regional Analgesia for Knee Surgeries: Thinking beyond Borders DOI: http://dx.doi.org/10.5772/intechopen.99282*

#### **Figure 14.**

*Probe position and sonoanatomy of various apporaches of i-PACK block. A: Anteromedial approach of i-PACK, B: Popliteal approach of i-PACK. (STM: Sartorius muscle, AMM: Adductor magnus muscle, PA: Popliteal artery, PV: Popliteal vein, TN: Tibial nerve, Gray line with blue glow: Needle track and drug spread between PA and femur).*

> [59–61]. It targets all innervations responsible for postoperative pain generations. Like conventional LIA, it is also given preoperatively before the beginning of the surgery after the primary mode of anesthesia (neuraxial or GA). This block consists of multiple injections around the knee joint (**Table 4**) except for the lateral spared area of the common peroneal nerve territory (**Figure 15**).

Since this block is given under ultrasound guidance targeting almost all of the innervations of the knee joint, the precision with this block is greater than the LIA given by the surgeon. Surgeons sometimes are reluctant to infiltrate near the popliteal artery in fear of injuring it.

#### *Topics in Regional Anesthesia*


#### **Table 4.**

*Injections sites of ultrasound-guided LIA or Ring block.*

**Figure 15.**

*Field block created by ultrasound-guided LIA or Ring block. (PA: Popliteal artery, SCN: Sciatic nerve, Blue area: Field block due to drug spread).*
