Injections require less organization, planning and have less morbidity.

February 2008

Relieving postoperative pain is an extremely important part of what we do as orthopedic surgeons. We all want to minimize postoperative pain and most believe in regional anesthesia, multimodal analgesia and in acute pain services. I think there is overwhelming evidence for regional anesthesia for both hip and knee arthroplasty. There is a lower mortality rate and there are significant decreases in morbidity in terms of blood loss, nausea, vomiting, respiratory depression and deep vein thrombosis.

The area of debate actually does not center on the use of spinal or perhaps epidural anesthetics during the procedure; it is in that immediate 24-hour postoperative period when the patients have most of their pain. For this, I advocate the use of periarticular injections.

Drawbacks to blocks

If you look at a typical patient after a hip or knee replacement, he or she has most of their pain in the immediate postoperative period and then, fortunately, it decreases. Most believe in preemptive multimodal analgesia and there is no debate that peripheral nerve blocks are effective in reducing this pain. There are a number of blocks that are available: lumbar plexus blocks, femoral blocks, 3-in-1 blocks, sciatic blocks, and obturator blocks. Their drawbacks are they take considerable organization and are not something that you can decide to do on your next operative day. Coordination with the assigned anesthesiologist is required to avoid unacceptable delays. Ideally, the anesthesiologist who has the skill set to perform peripheral nerve blocks will have access to a block room where it can be performed preoperatively. Also, the anesthetist will require special skills and they need special facilities which are often associated with surgical delay, so you need to be really organized to prevent these surgical delays.

There is also a drawback that many of these blocks are uncomfortable to the patient and I don’t think any of us would like to be a human pin cushion if we don’t have to be. A low incidence of complications has been reported (most major texts suggest 0.4%) including: infection; hematoma; actually injecting into the nerve, perhaps causing ischemia; pelvic organ perforation; toxicity; and patient falls. Perhaps some of these you can avoid with periarticular injections.

Periarticular injections

Periarticular injections followed by a multimodal analgesia protocol is a viable alternative to peripheral nerve block - we tend to use bupivacaine, epinephrine, preservative-free morphine, and ketorolac. I think they have a proven safety and efficacy.

Periarticular injections have proven efficacy and safety as published by Busch et al in 2006. For our technique, we like to use a small filter to basically infiltrate the structures around the hip as you do your hip replacement. These patients have virtually no pain for the first 12 to 16 hours following their procedure. Hence, periarticular nerve blocks provide an alternate, more patient-friendly method to relieve postoperative THR pain when compared to peripheral nerve blocks.

We have seen a substantial reduction in the need for PCA-type (patient-controlled analgesia) narcotics in the immediate postoperative period and perhaps more importantly, in the first 24 hours the difference is highly significant. Similarly, we saw a remarkable difference between injected and noninjected patients in terms of a visual analog for pain.

I believe the only area of contention is whether you need peripheral nerve blocks or can you use periarticular injections. We all believe in regional anesthesia. At this time, I think peripheral nerve blocks or periarticular injections should be considered. Multimodal analgesia and the use of an acute pain service really have revolutionized the care of patients who have total joint replacement surgery. The main issue is whether peripheral nerve block offer superior safety and efficacy when compared to peripheral nerve blocks.

To us, I think the periarticular injections are a good substitute for peripheral nerve blocks in minimizing pain after total hip replacement simply because they require less organization, they require less facilities, we think there is less potential morbidity to the patient and certainly less cost.

The ideal solution to the peripheral nerve block versus periarticular injection controversy would be a randomized clinical trail to determine the optimal method to minimize total joint replacement patient pain after surgery.

For more information:

• Robert B. Bourne, MD, FRCS(C), can be reached at London Health Sciences Center, 339 Windermere Road, Rm. C9-122, London, Ontario N6A 5A5, Canada, 519-663-3512  He has no direct financial interest in any product or company mentioned in this article.

References:

• Bourne RB. Peripheral nerve blocks: Optimal method to achieve a painless THA - opposes. Paper #104. Presented at the Current Concepts in Joint Replacement Spring 2007 meeting. May 20-23, 2007. Las Vegas.
• Busch SA et al. Efficiency of periarticular multimodal drug injection in total knee arthroplasty. J Bone Joint Surg. 2006;88A:959-963.