Glowing knee joint symbolizing pain relief after surgery.

Knee Surgery Breakthrough: How Local Infiltration Can Boost Recovery After Arthroplasty

Lena Voss in Health & Wellness December 2025 • 4 min read.

"A new study reveals the benefits of combining local infiltration of analgesia with femoral nerve blocks for faster recovery after total knee arthroplasty."

Total knee arthroplasty (TKA), a surgical procedure designed to restore function and relieve pain in damaged knee joints, has become increasingly common. While highly effective, managing post-operative pain remains a significant challenge. The goal is to help patients achieve early mobility and satisfaction.

Traditionally, multimodal analgesia, which combines various pain management techniques, has been used post-TKA. This includes local infiltration of analgesia (LIA) and femoral nerve blocks (FNB). While effective, questions remain about the best combination of these techniques for optimal results.

A recent study published in Knee Surgery, Sports Traumatology, Arthroscopy, sought to evaluate the additional benefits of LIA when combined with FNB in patients undergoing TKA. This research aimed to determine if this combination could lead to better pain control and improved functional outcomes compared to FNB alone.

Decoding the Study: LIA and FNB's Impact on Recovery

Glowing knee joint symbolizing pain relief after surgery.

The study, a double-blind randomized controlled trial, involved forty patients undergoing primary TKA. Participants were divided into two groups: one receiving a combination of LIA and FNB, and the other receiving FNB alone. The LIA involved injecting analgesic drugs (ropivacaine and dexamethasone) into the tissues surrounding the knee joint, while the FNB group received saline injections. Post-operative pain was managed using a patient-controlled analgesia (PCA) pump delivering fentanyl.

Researchers primarily measured the total amount of fentanyl consumed by patients in each group during the first 48 hours after surgery. Secondary measures included range of motion (ROM) of the knee, C-reactive protein (CRP) levels (an indicator of inflammation), pain scores, quadriceps strength, and functional assessments.

Reduced Opioid Use: The combination of LIA and FNB led to significantly less fentanyl consumption compared to FNB alone, suggesting better pain control.
Improved Knee Mobility: Patients receiving both LIA and FNB exhibited greater knee ROM on the second post-operative day.
Lower Inflammation: The LIA with FNB group showed significantly lower CRP levels on the third post-operative day, indicating reduced inflammation.
No Difference in Pain Scores: Visual analog scale (VAS) scores for pain at rest or during walking were similar between the two groups.

While pain scores were similar, the reduced opioid consumption and improved ROM suggest that LIA enhances the effectiveness of FNB in the early post-operative period. This could translate to faster rehabilitation and a quicker return to daily activities.

A Promising Path to Enhanced Recovery

The findings suggest that adding LIA to FNB provides superior pain relief and promotes faster recovery of knee ROM in the initial days following TKA. The reduction in opioid consumption is particularly noteworthy, given the potential side effects associated with opioid medications. This combination appears to be an effective strategy for post-operative pain management after total knee arthroplasty. Further research is needed to explore the long-term benefits and optimal protocols for LIA in TKA.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s00167-018-5322-7, Alternate LINK

Title: Additional Benefit Of Local Infiltration Of Analgesia To Femoral Nerve Block In Total Knee Arthroplasty: Double-Blind Randomized Control Study

Subject: Orthopedics and Sports Medicine

Journal: Knee Surgery, Sports Traumatology, Arthroscopy

Publisher: Springer Science and Business Media LLC

Authors: Koji Aso, Masashi Izumi, Natsuki Sugimura, Yusuke Okanoue, Yuko Kamimoto, Masataka Yokoyama, Masahiko Ikeuchi

Published: 2018-12-08

Everything You Need To Know

What is total knee arthroplasty?

Total knee arthroplasty (TKA) is a surgical procedure performed to alleviate pain and restore function in damaged knee joints. It involves replacing the damaged parts of the knee with artificial components. This procedure is crucial for individuals suffering from severe knee issues, aiming to improve their quality of life by enhancing mobility and reducing discomfort.

What is local infiltration of analgesia (LIA)?

Local infiltration of analgesia (LIA) involves injecting pain-relieving drugs, such as ropivacaine and dexamethasone, directly into the tissues surrounding the knee joint during TKA. This technique aims to provide localized pain relief and reduce the need for systemic pain medications. Its importance lies in controlling pain at the source, potentially improving early recovery outcomes by reducing inflammation and promoting greater knee range of motion.

What is a femoral nerve block (FNB)?

Femoral nerve blocks (FNB) involve injecting a local anesthetic near the femoral nerve to temporarily block pain signals from the knee. The purpose is to provide pain relief specifically to the knee area. FNBs are a vital part of the multimodal analgesia strategy, especially after TKA. This helps to provide pain relief, especially in the early post-operative period, facilitating easier movement and potentially speeding up the rehabilitation process.

Why is the combination of LIA and FNB important?

The combination of Local infiltration of analgesia (LIA) with femoral nerve blocks (FNB) is significant because it provides enhanced pain control and improved recovery outcomes following total knee arthroplasty (TKA). Studies show patients experience better pain relief, reduced opioid use, and increased knee mobility when both techniques are used together compared to FNB alone. The implications include faster rehabilitation, a quicker return to daily activities, and reduced reliance on medications associated with potential side effects.

Why is the measurement of knee range of motion important in the context of this study?

The study's findings on range of motion (ROM) of the knee are important because increased knee mobility is a key goal after Total Knee Arthroplasty (TKA). Improved ROM facilitates quicker rehabilitation and a faster return to daily activities. The combination of Local infiltration of analgesia (LIA) with femoral nerve blocks (FNB) showed greater knee ROM compared to femoral nerve blocks alone. This directly translates to improved functional outcomes and a better recovery experience for patients undergoing TKA.