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Experts debate current trends and goals for controlling post-arthroplasty pain
During the past 2 years, I have seen a major advancement in patients benefiting from the improvement in pain management following joint replacement. The majority of patients who had a joint replaced just a few years ago and undergo a subsequent arthroplasty now, are especially appreciative of the reduced pain they experience with current pain management programs.
To help bring our readers up to date on some of the latest thinking in this area, we asked Javad Parvizi, MD, FRCS, to assemble a panel of experts to share their insights and current practices as well as discuss what they see for the future.
Douglas W. Jackson, MD
Chief Medical Editor
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Javad Parvizi, MD, FRCS
Craig J. Della Valle, MD
Eugene R. Viscusi, MD
Richard H. Rothman, MD, PhDJavad Parvizi, MD, FRCS: How do you define “pain”?
Eugene R. Viscusi, MD: The International Association for the Study of Pain defines pain as “an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.” Pain is a complex process involving multiple neurohumoral pathways. While these concepts define pain in terms of its molecular basis and rationale for treatment, they miss the important clinical issue that pain is, in reality, whatever the patient says it is.
Parvizi: Can you briefly tell us how most common analgesics work?
Viscusi: There are a number of classes of pain drugs. Opioids are the most widely used potent analgesics; these drugs act at specific receptors present in the central and peripheral nervous system. Acetaminophen is the most widely used over-the-counter analgesic, and its pathway is likely purely central, but it remains puzzling. NSAIDs and COX-2 selective inhibitors have anti-inflammatory properties as well as peripheral and central anti-nociceptive properties. Local anesthetics work because they prevent neuronal firing, which is accomplished by blocking sodium channels. The list goes on and on.
Each class has its own mechanism or pathway of action, so it becomes easier to understand why using multiple drugs (multimodal analgesia) improves analgesia and reduces side effects by targeting multiple processes.
Parvizi: What, in your opinion, has been the most notable recent accomplishment in pain management following joint arthroplasty?
Richard H. Rothman, MD, PhD: Among the many advances, the most dramatic have been the introduction of extended-release epidural morphine. The latter has radically changed the paradigms for managing perioperative pain in hip and knee replacement patients. When properly and successfully utilized, this drug, which is a depo form of epidural analgesia, provides patients with 2 days of substantial pain relief. This has allowed for a rapid recovery program and early discharge from the hospital. This is not without its problems, however. Attention must be paid to the patient’s age and body mass to avoid respiratory depression.
Viscusi: There is now widespread application of some fairly old approaches, namely peripheral blocks and continuous regional anesthetic techniques using local anesthetics. These approaches dramatically improved pain control but require specific skills from the anesthesiologist. They also rely heavily on pump delivery technologies that are effective but require many resources to manage them properly, and they have also been associated with medication errors, pump programming issues and infection.
The application of aggressive multimodal pathways that include preoperative (or preventative) dosing have dramatically improved pain control. extended release epidural morphine (DepoDur, EKR Therapeutics Inc.) provides 48 hours of analgesia from a single epidural injection without an indwelling epidural catheter. This drug has proven to be a very effective analgesic for total joint arthroplasty (TJA) and it reduces the reliance on patient controlled analgesia (PCA) and epidural pumps.
Parvizi: How far have we come in regard to pain management after TJA?
Rothman: With the introduction of multimodal pain management and alternative analgesics, we are now able to mobilize patients early after their joint arthroplasty. This program — in conjunction with good preoperative education, discharge planning, multimodal pain modulation and a set of well-defined guidelines for rapid recovery — provides for a prompt return to normal function.
Parvizi: What does pre-emptive analgesia mean? Is this the same as preoperative analgesia?
Rothman: To me, it means administration of drugs or modalities before the pain starts. One of the main problems with postoperative management of pain also relates to nausea and vomiting. So pre-emptive administration of anti-emetics is also a very important part of pain management.
Nausea is one of the most common causes for delayed rehabilitation after surgery, and it can be successfully managed with pre-emptive medication. If pain management is handled with a combination of spinal and epidural analgesia, only modest supplemental drugs are needed, such as oral OxyContin (oxycodone, Purdue Pharma). The use of parental narcotics is minimized, since those drugs inherently slow down the patient’s capacity to return to normal function.
Craig J. Della Valle, MD: In my mind, pre-emptive analgesia means using a variety of medications and interventions, such as local anesthetic infiltration prior to the skin incision to blunt or potentially eliminate the pain response that is engendered by surgical intervention. By “staying ahead of the curve,” we can accomplish several things. First, we greatly decrease patients’ anxiety with the surgical procedure, which we have all learned is a very powerful part of enhancing the “patient experience.” Many patients are very scared of experiencing severe pain, and when it is avoided, the confidence engendered leads to a more rapid and pleasant recovery.
Second, we decrease the unwanted side effects of using larger doses of narcotic pain medications acutely to treat severe pain. Finally, by avoiding the intense pain associated with surgical intervention, in the long run, we may be decreasing the prevalence of later, neurogenic-type pain syndromes by preventing central sensitization.
I think that preoperative analgesia is a part of pre-emptive analgesia; however, the process continues throughout the perioperative period. For example, we recommend that our patients take pain medication prior to physical therapy (and not afterwards) so that they are both more confident and comfortable during therapy and avoid playing “catch-up” afterwards.
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We also recommend the continued use of COX-2 inhibitors for several weeks postoperatively, along with pregabalin (Lyrica, Pfizer), as research at our institution has shown better pain scores and, in patients undergoing TJA, improved range of motion and a lower incidence of late neurogenic-type pain when these agents are utilized.
Viscusi: Let me further confuse the topic by adding still another term. “Preventive analgesia” seems to be the emerging term, but all three terms have been used interchangeably. The heart of the concept is that certain pain pathways can best be interrupted before pain signaling occurs and often involves multiple drugs affecting more than one pathway. It harkens back to the multiple pathways and molecular basis of pain and the rational for multimodal pain management. The corollary is that pre- and postop intervention is probably needed to really see a benefit. There are short-term benefits on pain and functionality. What is really exciting is the emerging evidence that this approach may reduce chronic pain following surgery.
Parvizi: What is meant by multimodal pain management?
Rothman: A multimodal pain management program might include the use of spinal and epidural anesthesia, supplemented by peripheral nerve blocks, either femoral or sciatic nerve blocks, local injections of a “pain cocktail” at the operative site, and/or administration of narcotic-sparing drugs.
Della Valle: Multimodal pain management involves using several different classes of medications that act at various sites along the pain pathway to decrease the overall requirement for traditional narcotic pain medications, thereby reducing unwanted side effects. There is some evidence that this can also potentially reduce the prevalence of chronic pain syndromes, which are unfortunately relatively common after procedures such as total knee arthroplasty (TKA).
Parvizi: Does minimally invasive surgery have an influence on the degree and intensity of pain?
Rothman: Our clinical research data indicate that the magnitude of the incision has no impact whatsoever on postoperative pain, the speed of rehabilitation, blood loss or the need for narcotics. This does not imply that an excessively long incision is necessary, but on the other hand, there is no need to compromise a gentle complete exposure of the operative site that allows a technically perfect reconstruction.
Della Valle: This is a complex question that is poorly understood. My belief is that there are many factors that influence postoperative pain and a rapid recovery. A less-invasive exposure probably does have an effect, but clearly it is not as great as I, or many others, had thought several years ago. Other factors seem to be just as important, including the overall health and attitude of the patient pre-operatively, effective patient education, the use of pre-emptive multimodal pain protocols (as we have already discussed) and an accelerated postoperative rehabilitation program.
Many studies have attempted to address this question specifically; however, few have done so in a manner that really teases out the issues of skin incision size vs. deep tissue dissection. Dr. Lawrence Dorr’s 2007 study is among the best that I am aware of, whereby his group was able to randomize patients to a standard approach or a less-invasive approach and then extend the skin incision at the end of the case in an attempt to answer this question. The use of a less-invasive approach was associated with a shorter length of stay, a faster recovery and less pain in the early postoperative period. So, yes, I do believe that the surgical approach can influence the degree and intensity of pain, but it is only one piece of the puzzle.
Parvizi: Can you share some surgical pearls that you believe are important in minimizing postoperative pain?
Rothman: Gentle atraumatic dissection and tissue handling remain the keystones of successful surgery. Ironically, attempting to do a major operation through an excessively small incision results in increased stretching and trauma to the soft tissues and defeats the theoretical advantage. An adequate incision that does not stress the soft tissue, or the surgeon, also allows faster and more precise surgery, which yields obvious benefits to the patient.
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Della Valle: As Richard said, I think the first pearl is to use an incision size that allows you to perform the surgery safely, but without stretching the soft tissues. Avoiding complications is the first step in optimal patient outcomes. Some patients (ie, those who are large, muscular or who have had prior surgery) need a larger incision in order for you to get through the case properly.
The second pearl is getting to know your anesthesiologist and enlisting him or her as an ally to optimize patient outcomes. The use of specialized retractors and instruments to avoid tissue injury are also important.
When working around the knee, avoiding patellar eversion seems to have a substantial effect on postoperative pain. The concept of using the skin incision as a mobile window is also very helpful. You usually can only work on either the medial or lateral side of the knee at once, so you can avoid retracting in the opposite direction, which also decreases the risk of collateral soft-tissue damage through forceful retraction.
Parvizi: Why is TKA more painful than total hip arthroplasty (THA)?
Della Valle: Perhaps for a number of reasons. The amount of soft-tissue coverage is smaller around the knee compared to the hip, tight closure of the knee capsule (which may be stretched by postoperative hematoma), and also the amount of actual bony work performed is much greater when performing a total knee. All of these factors may lead to greater postoperative pain in TKA.
Rothman: The answer to this dilemma is uncertain. Unequivocally, total knees are more painful than total hips, but the explanation remains elusive. It may be that the more relaxed soft tissues about the hip allow for a reasonable degree of perioperative swelling as compared to the tighter envelope around the knee joint.
Viscusi: TKA involves more tissue and bone trauma and usually requires a longer operation. The knee is a more complicated joint from a pain standpoint, with widespread pain generators.
Parvizi: Can you tell us what is on the horizon for pain management?
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Viscusi: This is a tremendously exciting area of study, although much of it is still early in its development. There is a lot of interest in local delivery of drugs to avoid systemic effects and toxicities. There are a number of what I would consider “extended-release local anesthetic delivery systems” that require no external pump or catheter.
There are some novel drugs in development for local delivery, including a capsaicin preparation that has specificity for C-fibers. There is also a fentanyl iontophoretic transdermal system (IONSYS, Ortho-McNeil) that is patient-controlled, needle-free and roughly the size of a credit card. The device sticks on the patient’s arm and only delivers the drug with patient activation. This would reduce some of the burdens associated with standard intravenous patient-controlled analgesia.
I suspect multimodal approaches will become commonplace in orthopedic analgesia.
Parvizi: What role do other factors such as patient and family education, rehabilitation, and patient preconditioning play in perception of pain?
Della Valle: We have had a preoperative patient teaching program at Rush for many years, and I believe this is critical to optimizing patient outcomes. When patients know what to expect, they have less anxiety and have a much easier time in the hospital.
Patient preconditioning is also very important in the treatment process. My early experience with hip resurfacing has made this very clear to me. For me to perform a hip resurfacing safely, I need to make a large incision and completely release the short external rotators, the quadratus and the gluteus maximus insertion. Despite a substantial increase in soft-tissue dissection, these patients seem to get better just as fast, if not faster, than my conventional total hips performed with a less-invasive approach using the same perioperative protocols. Is it because they are generally young, active males who want a hip resurfacing? Is it because we do not invade the medullary canal? I am not sure we know the answers to these questions, but patient preconditioning is definitely part of the answer.
Rothman: A well-informed and educated patient has less anxiety and, therefore, will experience a lower degree of subjective pain response than a poorly informed, apprehensive patient. This reassurance and education can be efficiently delivered through nurse-conducted preoperative educational programs and proper postoperative planning. Eliminating the fear of the unknown is fundamental to successful and peaceful surgery.
Parvizi: What are the consequences of inadequate pain control?
Della Valle: The predominate consequences of inadequate pain control are increased patient anxiety and the unwanted side effects from using larger doses of narcotic pain medications: sedation, nausea and vomiting. It is a big patient confidence-builder to get them up and ambulating immediately after surgery, and you just can’t do that if they are in an unreasonable amount of pain or nauseous.
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Rothman: Lack of an adequate pain control program results in intermittent spikes of pain, anxiety, fear and anger among our patients. This will slow down the rehabilitation process, restrict restoration of motion and promote a sense of hostility among the patient, nursing staff and physician. Patients will be reluctant to have further surgery and often are delayed in their discharge from the hospital.
Viscusi: The consequences are manifest: poorer physical therapy leading to poorer functionality and recovery, increased sympathetic drive that could be linked to cardiac events, hypercoagulation, hyperglycemia, misery and poor patient satisfaction.
Parvizi: Is one anesthesia technique better than another with regard to postoperative pain?
Viscusi: There is no question that regional anesthetic techniques provide an extended period for analgesia. This might result in less “sensitization,” with an impact on pain well after the local anesthetic effect dissipates.
Parvizi: Is there a difference between cemented and uncemented TJA with regard to postoperative pain?
Della Valle: I personally have not seen much of a difference in my own practice between my cementless and hybrid total hips. On the knee side, there are some data to suggest that cementless knees may take longer to become pain-free than their cemented counterparts.
Rothman: A well-performed cementless joint replacement should have achieved solid fixation during the surgical procedure, which should be the equivalent of a cemented arthroplasty. Thus, there will be little difference in the amount of postoperative pain perceived by the patient. A poorly fixed implant will be provocative of pain whether it is cemented or cementless.
Parvizi: How do you handle postoperative anticoagulation and epidural catheters in your institution?
Della Valle: We use Coumadin (Warfarin sodium, Bristol-Meyers Squibb) and start dosing patients on the night of surgery. For our “fast track” patients, the epidural is removed on the morning of postoperative day 1, while patients who we believe are going to be in the hospital longer have the epidural removed on the morning of postoperative day 2, so long as the international normalized ratio (INR) is less than 1.8. We shoot for a goal INR of 2.0 and anticoagulate patients for 3 weeks.
Viscusi: The short answer is that we pay attention to the guidelines on anticoagulation and neuraxial anesthetics published by the American Society of Anesthesiologists to avoid epidural hematoma formation. These are the standards to which we are held. However, these are guidelines and should be used in the context of the risk/benefit ratio of the particular clinical situation. In other words, you have to weigh the relative risk of an epidural hematoma vs. a fatal pulmonary embolus in some situations. Is it worth stopping or reversing anticoagulation in all TJA patients with a slightly prolonged INR? You have to use your clinical judgment and document your reasoning. Try to adhere to the American Society of Regional Anesthesia and Pain Medicine guidelines, but don’t apply them inflexibly.
Parvizi: Are there modalities other than conventional analgesia that may be used to control pain after TJA?
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Viscusi: There is an old adage in pain management: “First try a cold pack, then a hot pack, and then if all else fails, try a six pack!” Seriously, the evidence for cryotherapy is pretty convincing. It is low-risk and low-cost. What is there to lose? Transcutaneous electrical nerve stimulation therapy has some efficacy, as does acupuncture. Some patients have a benefit with self-hypnosis, particularly for controlling side effects. Other than cryotherapy, however, the contribution of these other techniques has been limited.
If I could make one simple, inexpensive intervention, it would be better patient preoperative education about analgesic choices, how to use them effectively, and how to deal with the side effects.
Parvizi: If you had a crystal ball, what would you predict pain management would look like for TJA in 5 years?
Viscusi: To keep pace with the changes in health care, pain management will also need to change. I predict that pain management will become less invasive and less dependent on cumbersome pump and catheter delivery systems. These approaches consume a lot of labor and resources and are becoming less compatible with the clinical needs.
Future technologies are likely to involve more local delivery with extended duration characteristics, rather than systemic drugs. Multimodal therapies with preoperative dosing will become the routine. Emerging technologies are likely to promote “patient-focused” rather than “equipment-focused” therapy.
For more information:
- Craig J. Della Valle, MD, can be reached at the Department of Orthopedics, Rush University Medical Center, 1725 W. Harrison St., Ste. 1063, Chicago, IL 60612; 312-243-4244.
- Javad Parvizi, MD, FRCS, can be reached at the Rothman Institute, 925 Chestnut St., 5th Floor, Philadelphia, PA 19107; 267-339-3617. He is a paid consultant for Stryker and he receives grant/research support from the National Institutes of Health, Aircast, Glaxo Smith Kline, Ortho McNeill, Pfizer, Smith & Nephew and Stryker.
- Richard H. Rothman, MD, PhD, can be reached at the Rothman Institute, 925 Chestnut St., 5th Floor, Philadelphia, PA 19107; 267-339-3500.
- Eugene R. Viscusi, MD, can be reached at the Department of Anesthesiology, Jefferson Medical College, Thomas Jefferson University, 8490 Gibbon Building, 111 South 11th St., Philadelphia, PA 19107; 215-955-6161; e-mail: Eugene.Viscusi@jefferson.edu. He is a consultant for Ortho-McNeil/PriCara Pharmaceutical Inc., Adolor Corp., Johnson & Johnson, Cadence, Anesiva, Wyeth YMBiosciences.
References:
- American Society of Anesthesiologists Consensus Statement can be viewed at www.asra.com.
- Dorr LD, Maheshwari AV, Long WT, et al. Early pain relief and function after posterior minimally invasive and conventional total hip arthroplasty. A prospective, randomized, blinded study. J Bone Joint Surg (Am). 2007;89(6):1153-1160.