Publication:

Periarticular local infiltration analgesia and early recovery after primary total knee arthroplasty: a prospective observational study

Background Postoperative pain after total knee arthroplasty (TKA) may delay mobilization and increase opioid use. Periarticular local infiltration analgesia (LIA) is a motor-sparing technique. This study evaluated pain relief and functional recovery after a periarticular LIA protocol in primary TKA.

Methods This prospective observational study included 40 patients aged >45 years with grade IV osteoarthritis undergoing primary TKA from May 2023 to November 2024. Deep injection before cementation contained bupivacaine 0.5% 24 ml, morphine 8 mg/ml 0.8 ml, methylprednisolone 40 mg/ml 1 ml, cefuroxime 750 mg in saline 10 ml, saline 22 ml, and epinephrine 1:1000 0.3 ml. Superficial injection before closure contained bupivacaine (0.5%) 20 ml and saline 20 ml. The primary outcome measure was postoperative pain intensity, assessed using the visual analogue scale (VAS) at 6, 12, and 24 hours.

Results Mean age was 60.4±7.8 years; 55% were female. Mean VAS scores were 3.1±1.2, 2.4±1.1, and 1.8±0.9 at 6, 12, and 24 hours. Mean rescue opioid use was 4.2±3.3 mg intravenous morphine equivalents; 70% required ≤5 mg. Assisted ambulation within 12 hours occurred in 87.5%, unassisted straight-leg raise within 24 hours in 72.5%, mean knee flexion at 48 hours was 82°±12°, and mean hospital stay was 5.7±1 days. Knee society score improved from 45±8 to 78±7 at 6 weeks and 85±6 at 3 months.

Conclusions A two-stage periarticular LIA protocol with a total volume of 98.1 ml was associated with low early pain scores, modest opioid use, early mobilization, and favorable recovery after primary TKA.