Motor-sparing peripheral nerve blocks for hip and knee surgery

To summarize the recent literature describing and comparing novel motor-sparing peripheral nerve block techniques for hip and knee surgery. This topic is relevant because the number of patients undergoing same day discharge after hip and knee surgery is increasing. Preserving lower extremity muscle function is essential to facilitate early physical therapy for these patients.

Distal peripheral nerve blocks may allow for preserved quadriceps motor strength and comparable analgesia to traditional techniques. However, few studies in hip and knee populations include strength or function as primary outcomes. For hip surgeries, studies have failed to show analgesic differences between regional blocks and periarticular infiltration. Similarly for knee arthroplasty in the absence of periarticular infiltration, recent evidence suggests adding combinations of blocks (ACB plus iPACK or genicular nerve blocks) may balance pain control and early ambulation.

The use of motor-sparing peripheral nerve block techniques enables early ambulation, adequate pain control, and avoidance of opioid-related side effects facilitating outpatient/ambulatory lower extremity surgery. Further studies of these techniques for continuous peripheral nerve block catheters are needed to assess if extended blockade continues to provide motor-sparing and opioid-sparing benefits.