Background The postoperative analgesic potential of periarticular anesthetic infiltration (PAI) after TKA is unclear as are the complications of continuous femoral nerve block on quadriceps function. Questions/purposes We asked (1) whether PAI provides equal or improved postoperative pain control in comparison to a femoral nerve block in patients who have undergone TKA; and (2) if so, whether PAI improves early postoperative quadriceps control and facilitates rehabilitation. Methods We randomized 60 patients to receive either PAI or femoral nerve block. During the first 5 days after TKA, we compared narcotic consumption, pain control, quadriceps function, walking distance, knee ROM, capacity to perform a straight leg raise, and active knee extension. Medication-related side effects, complications, operating room time, and hospitalization duration were compared.