Postoperative analgesia in total knee arthroplasty for posttraumatic arthritis: A randomised controlled trial comparing patient-controlled intravenous analgesia, continuous femoral/sciatic nerve block and continuous local infiltration analgesia

PURPOSE: Postoperative pain remains a major obstacle to early mobilisation following total knee arthroplasty (TKA) and is particularly challenging in patients with posttraumatic arthritis due to prior injury, scarring, and complex surgeries. While various analgesic strategies have been evaluated in degenerative TKA, evidence in posttraumatic cases is lacking. This study is the first to compare patient-controlled intravenous analgesia (PCIA), continuous femoral/sciatic nerve block (cFNB/cSNB), and continuous local infiltration analgesia (cLIA) in this specific population. METHODS: In this prospective, monocentric, randomised controlled trial, 92 patients undergoing TKA for posttraumatic arthritis were allocated to PCIA (n = 31), cFNB/cSNB (n = 30) or cLIA (n = 31). Postoperative pain was assessed using the numeric rating scale (NRS) from day 1 (t1) to discharge (t6). Secondary outcomes included range of motion (ROM), rescue analgesic use, Knee Society Score (KSS) and patient satisfaction. Statistical comparisons between groups were performed using adjusted pairwise tests. RESULTS: At t1, patients in cFNB/cSNB reported significantly lower pain scores compared to cLIA (p = 0.039). cLIA required significantly more rescue analgesics at t1/t2 (both p < 0.05). Active/passive knee flexion was consistently higher in cFNB/cSNB from t1 to t6 (all p < 0.05). No differences were observed in postoperative mobility, KSS or satisfaction. All groups showed significant improvement in pain and ROM over time. CONCLUSIONS: In patients undergoing TKA for posttraumatic arthritis, cFNB/cSNB provided superior early postoperative pain control and functional recovery compared to PCIA and cLIA. The findings suggest that standard fast-track protocols may not be fully applicable in this complex patient population, highlighting the need for individualised analgesic strategies. LEVEL OF EVIDENCE: Level I.