Posterior Capsular Injection With Femoral Nerve Block for Total Knee Arthroplasty

Patients undergoing total knee replacement surgery experience severe post-operative pain.
Continuous femoral nerve block combined with selective tibial nerve block provides optimal
pain control in the anterior and posterior aspect of the knee respectively. However, in
patients with pre-existing neuropathy of the sciatic nerve, the blockade of tibial nerve is
contraindicated because of increased risk of nerve damage that may lead to exacerbation of
neurologic symptoms. In such patients where selective tibial nerve block cannot be offered,
ultrasound guided posterior knee capsular injection may be an alternative technique for
controlling posterior knee pain after surgery. Posterior capsular injection by surgeons
intraoperatively, when combined with femoral nerve block has been shown to provide pain
control after total knee replacement. With posterior capsular injection, the main trunk of
the tibial nerve is spared and only the terminal nerve endings innervating the posterior knee
joint is blocked providing effective pain control. In this study, the efficacy of ultrasound
guided posterior capsular injections performed pre-operatively will be compared to tibial
nerve block in controlling knee pain after surgery.

The results of this study may help establish the efficacy of ultrasound guided posterior
capsular injection as an alternative to tibial nerve block in patients undergoing total knee
arthroplasty.

Inclusion Criteria:

- Patients having primary, unilateral total knee arthroplasty

- Age 18-80

Exclusion Criteria:

- History of neurologic disease, neuropathy, diabetes, or major systemic illness

- Allergy to local anesthetic solution or NSAIDs

- Pregnancy

- Chronic use of narcotics

- Inability to give consent/cooperate with study