Optimizing perioperative management in UKA: Role of ropivacaine in local infiltration analgesia
20 Feb 2026
Unicompartmental knee arthroplasty (UKA) is a minimally invasive procedure that is well suited to early mobilization and can therefore be done as day surgery, while local infiltration analgesia (LIA) is an important part of multimodal pain management that supports enhanced recovery after surgery (ERAS). Various practical strategies can aid perioperative management of UKA, and choosing a suitable local anaesthetic, such as ropivacaine, for LIA is crucial for optimizing postoperative outcomes, according to insights presented at a local symposium.
Role of pre‑anaesthetic clinics
ERAS protocol for UKA aims to optimize care across the preoperative, intraoperative and postoperative phases, lower complication rates, shorten hospital length of stay (LoS), and accelerate rehabilitation. Suitable and effective analgesia, early mobilization, and pain management remain central to optimizing recovery. [Orthopedics 2025;48:87-97; Br J Anaesth 2025;134:510-522].
In the preoperative phase, pre‑anaesthetic clinics (PACs) play an important role by facilitating completion of essential investigations, identifying anaesthesia-related risk factors, and providing a detailed assessment that helps relieve patients’ anxiety. A PAC consultation also helps determine the appropriate mode of anaesthesia and provides an opportunity to prescribe pre-emptive analgesics to patients. [BMJ Open 2022;12:e054206; Curr Opin Anaesthesiol 2011;24:326-330]
Pre‑emptive analgesics typically include a combination of a cyclooxygenase-2 (COX-2) inhibitor, paracetamol, and pregabalin. They help to alter central processing of pain signals, which would otherwise amplify discomfort after joint replacement surgery. [Appl Sci 2023;13:3798; BMC Musculoskelet Disord 2008;9:77; J Arthroplasty 2002;17:129-133]
Anaesthesia options and benefits of LIA
Intraoperatively, spinal anaesthesia is often preferred over general anaesthesia for joint replacement surgeries, including total knee arthroplasty (TKA), to facilitate postoperative recovery. [J Arthroplasty 2023;38:673-679]
While multiple regional anaesthesia techniques are available for pain control, they are often technically demanding and come with their own challenges. Epidural anaesthesia can cause hypotension and urinary retention, and nerve blocks carry a risk of quadricep weakness, which can interfere with early mobilization and slow down rehabilitation. [Acta Orthop 2009;80:213-219; Br J Anaesth 2008;100:154-164; J Arthroplasty 2012;27:1234-1238]
LIA, in contrast, is a relatively simple yet effective anaesthetic technique with fewer side effects of muscular weakness compared with nerve block, which has been recommended by the ERAS Society’s guidelines for knee replacement. In a 2012 study, LIA demonstrated comparable pain control efficacy vs continuous femoral nerve block in TKA, while also offering a more convenient and cost-effective method of administration, highlighting the efficiency of the approach in terms of manpower and time. [J Orthop Surg Res 2020;15:41; Br J Anaesth 2025;134:510-522; Acta Orthop 2020;91:3-19; J Arthroplasty 2012;27:1234-1238]
Ropivacaine: Preferred local anaesthetic for LIA
Periarticular cocktail injections typically include a local anaesthetic, an NSAID, adrenaline, and saline, with the choice of local anaesthetic playing a critical role. Among the available local anaesthetics, ropivacaine is the preferred option in LIA due to its proven efficacy and safety profile, according to the Expert Consensus on Perioperative Pain Management for Accelerated Orthopedic Rehabilitation 2022. [Appl Sci 2023;13:3798; Eur J Anaesthesiol 2020;37:1157-1167; Integr Pharm Res Pract 2025;14:99-112]
A recent rapid health evaluation study assessed commonly used local anaesthetics after hip and knee arthroplasty across pharmaceutical properties, effectiveness, safety, and other attributes. Compared with liposomal bupivacaine (65.06), levobupivacaine injection (60.35), and bupivacaine injection (61.05), ropivacaine injection achieved the highest overall scores of 68.97 out of 100, reflecting strong efficacy data and an established safety profile with fewer adverse events. (Figure) [Integr Pharm Res Pract 2025;14:99-112]
While ropivacaine, levobupivacaine, and bupivacaine are all pipecolylxylidine local anaesthetics, ropivacaine has the lowest motor-blocking potency of the three. (Table) Ropivacaine selectively blocks sensory nerve fibres and, at lower doses, produces only limited, nonprogressive motor block, which helps preserve quadricep function, encourages earlier mobilization, and supports patients’ postoperative rehabilitation. In contrast, bupivacaine, being more lipophilic, is more likely to penetrate large, myelinated motor fibres and produce a stronger motor block. Similarly, levobupivacaine has been associated with a risk of permanent muscle weakness or sensory impairment. Due to these properties, bupivacaine and levobupivacaine are less optimal choices for enhancing recovery and postoperative outcomes. [Anesth Analg 2007;104:904-907; Integr Pharm Res Pract 2025;14:99-112; Naropin Hong Kong Prescribing Information; Br J Anaesth 2025;134:510-522; Indian J Anaesth 2011;55:104-110]
Ropivacaine also has lower cardiovascular and central nervous system (CNS) toxicity than bupivacaine, as confirmed in both animal studies and healthy volunteers exposed to neurotoxic doses, mainly due to its lower lipophilicity and stereoselective properties. These characteristics further highlight the favourable safety profile of ropivacaine, even when large volumes are used for periarticular infiltration. [Indian J Anaesth 2011;55:104-110; Naropin Hong Kong Prescribing Information; J Arthroplasty 2012;1234-1238]
Addition of steroid to LIA
Steroids may also be added to LIA to enhance postoperative recovery. In a double-blind, paired, randomized trial involving 46 bilateral TKA patients, all patients received 16 mg of intravenous dexamethasone, each with one knee receiving LIA cocktail with triamcinolone 40 mg and another knee receiving LIA cocktail without corticosteroid. The knee treated with both intravenous and periarticular steroids showed greater range of motion from postoperative days 2 to 4 (p<0.05) and achieved straight leg raise sooner than the knee that received intravenous steroids alone (p<0.05), suggesting that adding a corticosteroid to the LIA cocktail provides additional clinical benefits. No increase in wound complications or infection was observed. [J Arthroplasty 2021;36:130-134.e2]
Postoperative pain and symptom control
ERAS postoperative care emphasizes multimodal strategies for pain and symptom control, together with rehabilitation and early physiotherapy. The core principle of postoperative pain control is multimodal analgesia, which involves using different classes of analgesics at the same time to enhance overall pain relief through synergistic effects, minimizes side effects associated with any single drug, and avoids the need for opioids. Current protocols typically include regular oral medications such as paracetamol, pregabalin, and a COX‑2 inhibitor, with short-acting oral opioids reserved for breakthrough pain. [Appl Sci 2023;13:3798; Br J Anaesth 2025;134:510-522; Ann Transl Med 2019;7:69; Medicine (Baltimore) 2023;102:e32941; Eur J Anaesthesiol 2020;37:1157-1167]
Within this multimodal framework, LIA with ropivacaine serves as an effective strategy for postoperative pain management and opioid reduction. In a randomized, double‑blind study of 40 patients undergoing UKA, LIA significantly lowered pain scores at rest and during movement compared with placebo, resulting in reduced morphine consumption in the first 48 hours postoperatively (21 vs 67 mg; p<0.001). [Br J Anaesth 2025;134:510-522; Acta Orthop 2009;80:213-219]
Common postoperative symptoms of knee surgery include nausea and vomiting, dizziness, and urinary retention. To better manage these symptoms, it is important to minimize surgical time, avoid unnecessary opioid use, use intravenous fluids judiciously, and implement urinary retention protocols. [Acta Orthop 2020;91:3-19; J Arthroplasty 2021;36:130-134.e2; Disabil Rehabil 2023;45:4252-4258; Orthop Nurs 2023;42:179-187]
Benefits of reduced LoS and early mobilization
Reducing hospital LoS contributes to functional recovery and allows patients to return to independent living sooner. Based on ERAS recommendations, mobilization should begin as early as possible after surgery, depending on patients’ ability, to help them meet discharge goals sooner. A previous study on TKA highlighted the impact of early mobilization on LoS, where patients mobilized on postoperative day 0 (POD 0) vs POD 1 demonstrated significantly reduced LoS (p=0.002) with a higher percentage of discharge to home instead of rehabilitation (p=0.035). [Ann Transl Med 2019;7:69; Acta Orthop 2020;91:3-19]
Choosing a sensory-selective, motor-sparing local anaesthetic such as ropivacaine for LIA helps minimize muscle weakness, enabling earlier patient mobilization and supporting the ERAS objective of shortened LoS or even same-day discharge in knee arthroplasty. [Naropin Hong Kong Prescribing Information; Br J Anaesth 2025;134:510-522; Acta Orthop 2020;91:3-19]
Conclusion
Adopting ERAS protocols in UKA enhances recovery through multimodal analgesia, early mobilization, and reduced hospital stay, with ropivacaine-based LIA further supporting effective pain control and preserved motor function.
