Long-term pain and functional disability after total knee arthroplasty with and without single-injection or continuous sciatic nerve block in addition to continuous femoral nerve block: a prospective, 1-year follow-up of a randomized controlled trial.

BACKGROUND AND OBJECTIVES: This is a follow-up to determine long-term outcomes after total knee arthroplasty (TKA) in patients enrolled in a previous randomized trial that found reduced postoperative pain after addition of sciatic nerve block to continuous femoral nerve block for TKA.

METHODS: Physical function after TKA was evaluated at 3 and 12 months in patients (n = 89) receiving continuous femoral nerve block alone (group F), combined with a single-injection (group Fs) or continuous sciatic nerve block (group FCS) after TKA, until the second postoperative day. Physical function, stiffness, and pain were measured by using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Oxford Knee Score 12-item knee questionnaires, and visual analog scale at rest and during mobilization before TKA and 3 and 12 months afterward. Post hoc, a median split on poor functioning (WOMAC) was analyzed.

RESULTS: Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Knee Score 12-item knee, and visual analog scale scores improved significantly in all patients, without any differences among groups. Median (range) WOMAC at 3 months were in group F, 83 (20-97); group Fs, 72 (25-99); and group, FCS 76 (28-100) and at 12 months 87 (35-98), 77 (43-100), and 89 (35-100), respectively.

CONCLUSIONS: No differences were detected in the secondary outcomes we examined. Thus, improved postoperative outcome did not translate into improved functional outcome or long-term pain.