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Lake Manyara, Tanzania - photo by JoAnn Sturman
Some surgeons prefer femoral nerve blocks for post op pain relief following TKA. Due to quadriceps weakness, physical therapy is not scheduled until the day after surgery. The femoral nerve block alone does not afford complete pain relief, and patients often require narcotic supplements. Spinal narcotics may mitigate the incomplete coverage, but nausea, vomiting, and pruritis are a concern. The following describes a technique which provides extended and complete post op pain relief.
The objective of the block is not to provide surgical anesthesia but rather long lasting post op analgesia with retention of some motor function. The duration of these blocks is volume dependent and requires the use of 200 mg of .25% bupivacaine with decadron and buprenorphine placed under ultra sound guidance.
The patient, a 78 year old male, received no pre op narcotics. He underwent femoral and popliteal blocks after receiving fentanyl 50 ug. Each block consisted of a mixture of 40 ml of .25% bupivacaine with decadron 5mg and buprenorphine .15 mg. The patient received general anesthesia, and although surgical stimulation was blunted by the block, the reduced local anesthetic concentrations did not provide surgical anesthesia during the osteotomies.
The patient was pain free and received no narcotics in the recovery room. Although his leg was numb and lacked normal strength, he was able to move it. He was transferred to the floor, where he experienced a 37 hour pain free interval.
The technique has been used for out patient ACL patients, who are discharged with a knee brace. In this younger group of patients analgesia lasted 30 hours post block. In these cases .25% bupivacaine prevents most surgical surgical stimulation, so patients receive the added benefit of being carried on less than 1 MAC anesthesia.
Iguasu Falls, Argentina - photo by JoAnn Sturman
