Pain management post Total Knee Arthroplasty (TKA) has improved significantly over the last decade with the current practice involving a multimodal strategy. One of the most important issues concerning patients is immediate postoperative pain. Post TKA , upto 60 % patients have severe knee pain and 30% have moderate knee pain. Effective pain management using a multimodal approach promises to decrease complications, improve outcomes, and increase patient satisfaction after hip and knee arthroplasty. Current strategies involve using peripheral nerve blockade, periarticular injections, and multimodal oral opioid and nonopioid medications during the perioperative and postoperative periods to provide superior pain control.

Local periarticular infiltration of analgesic agents has been found to effectively control pain and improve functional outcome. A cocktail of drugs like bupivacaine, ketorolac, epinephrine and saline are being used. Peripheral nerve blocks help improves pain control and reduces opioid requirements. Femoral nerve bocks significantly improve analgesia control and shortens the time of functional recovery as compared to epidural analgesia or intravenous opioids. Femoral nerve blocks are associated with reduction in quadriceps strength and increased chances of fall. This in turn delays functional recovery and lengthens hospital stay. Adductor canal block (ACB) is a relatively newer technique for pain management. It helps improve quadriceps function as opposed to femoral nerve blocks which reduces quadriceps function. At the same time, the analgesic effect of adductor canal block is comparable to that of femoral nerve block. Anatomical study of adductor canal showed that the adductor canal contained multiple afferent sensory nerves (e.g. saphenous nerve, medial femoral cutaneous, and medial retinacular nerve etc.) but only a single efferent motor nerve (vastus medialis of the quadriceps muscle) that potentially affected motor function^. Therefore, ACB may have a minimal effect on quadriceps muscle strength, but provides a comparable level of pain relief and early mobilization. Pepper et al [1] in their cadaveric study used a 1.5 inch 18 gauge blunt fill needle directed posteriorly at the level of the adductor tubercle in the supracondylar region, angled approximately 15° medial in relation to the sagittal plane, with the needle buried until the syringe hub met resistance to access the adductor canal. They found that this method had an 86% accuracy in accessing the adductor canal with no episode of damage to the femoral artery. They state that intraoperative ACB augmentation of peri articular infiltration is anatomically feasible and safe.

Various studies show that adductor canal block is an effective tool in controlling pain post TKA. [2] Routine practice involves ultrasonography guided adductor canal block given pre operatively. It involves injecting in the distal adductor canal with a success rate as high as 95.6%. Pepper et al found that it was possible to reach the distal adductor canal from the joint, thereby eliminating the need of an extra procedure in giving adductor canal block. Max Greenky et al found that surgeon administered adductor canal block is not inferior to anesthetist administered adductor canal block[3].

To the best of our knowledge there is no study assessing the additive effects of adductor canal infiltration given intraoperatively from the joint. (Search engines used : PubMed, OVID, Elsevier, JBJS, Google Scholar).

We believe this to be an easy and efficient method of adductor canal infiltration thereby decreasing the cost to the patient and removing the need of an extra invasive procedure after the surgery.

1)ResearchQuestion:Does intraoperative adductor canal infiltration from primary exposure of joint have an additive effect on postoperative pain management and early functional recovery in patients undergoing TKA ?

  Aims :

 To assess additive effect of intraoperative adductor canal infiltration in management of postoperative pain in patients undergoing TKA and  early postoperative function post TKA