Manejo del dolor después del reemplazo total de articulación.(Inglés)

By Eric A. Monesmith, MD

New techniques and protocols improve patients’ postoperative experience.

From left, Sharon Neesen, patient; Eric A. Monesmith, MD; Sandra Groce, patient; and Josie Poole, PA. Total hip and knee replacements are two of the most successful operations performed in medicine. A recent NIH consensus conference confirmed that total knee replacement reliably relieves pain and improves function in patients suffering knee arthritis.1 According to statistics on file with the American Academy of Orthopaedic Surgeons, using hospital discharge data from 2003, approximately 220,000 total hip replacements and nearly 420,000 total knee procedures are done each year in the United States.2 This number is likely to grow as the demographics of our country change and continue to age, in addition to expanding indications for younger patients to receive joint replacements.

Over the past few years, there has been intense interest in the development of minimally invasive surgery (MIS) for joint replacement. Coincident with this has been the development of new techniques and protocols for pain management after these surgeries, as well as new rehabilitation protocols. Thus far, there has been little published data that support the widespread use of MIS surgery. In fact, some of the published data show higher complication rates and little, if any, benefit other than improved cosmesis.3-5

Debate continues over whether the purported benefits of MIS are from the surgery, or from better pain management and/or improved rehab protocols. These issues are complex and multifactorial, and it is proving difficult to sort out exactly which provides the most benefit. However, there can be no doubt that it is much easier to implement new pain management or rehab protocols than to learn new, complex surgical techniques. The purpose of this article is not to debate the merits of MIS surgery, but to describe pain management protocols that may help improve a patient's total joint replacement experience, regardless of the surgical approach.

NEW THINKING To begin, we must change the way we think about postoperative pain management. We need to think more globally, and talk about perioperative pain management. Furthermore, strategies to reduce postoperative nausea and vomiting (PONV) are absolutely necessary to complement the pain management program. A patient who is nauseous and vomiting for 24 hours after surgery cannot participate in rehab and is going to remember the postoperative experience as miserable, regardless of their pain management.

This effort involves more than just increasing the dose of pain medication we give. We use preoperative anti-inflammatories starting 48 hours in advance of surgery, an aggressive perioperative antiemetic program, blood loss management, regional nerve catheters for total knee replacement, scheduled narcotics with additional prn medications, and less-invasive surgical techniques (not necessarily MIS).

The basic idea is to preempt the pain signals, prevent PONV, and attack these issues from different angles, using a multimodal therapeutic approach. The multimodal approach targets different areas of the pain pathway. Celecoxib inhibits prostaglandin synthesis, primarily via the inhibition of cyclooxygenase-2 enzyme, reducing the inflammatory mediated pain signals. The mechanism of hydrocodone or oxycodone is not precisely understood, but it is believed to work on opiate receptors in the central nervous system to inhibit pain. Acetaminophen elevates the pain threshold, effectively improving analgesia.

PONV can negatively affect even the most well-done surgery and cause patients great distress, slow down their recovery, and greatly diminish the quality of their postoperative experience. To prevent this, we use round-the-clock, scheduled, antiemetics. Zofran (ondansetron HCL) is a serotonin 5-HT3 antagonist. Whether its action may be central or peripheral or both remains unclear, but release of serotonin in response to stress may stimulate the vagal afferents, causing vomiting, and Zofran appears to prevent this. Scopolamine is an anticholinergic that works in the central nervous system to block cholinergic transmissions from the reticular formation to the brain's vomiting center. Prevacid (lansoprazole and naprapac) is a proton pump inhibitor that works to reduce gastric acid secretions.

Implementing these programs is something that all total joint surgeons, from high volume to occasional, can do to make a positive impact on patient care and hopefully improve outcomes.

Below, I describe our program in detail when using a single-shot spinal with bupivacaine and Duramorph for either total knee or total hip replacement. Later, I will discuss how this protocol changes when we utilize intraoperative femoral and sciatic nerve blockade, followed by continuous femoral nerve infusion (CFI) postoperatively.

Preoperative. If the patient is not truly sulfa allergic, celecoxib 400-600 mg a day starting 2 days prior to surgery. There are data demonstrating reduced pain and narcotic usage in TKR using Cox-2 NSAIDs to support the use of this.6 This will not interfere with the deep venous thrombosis prophylaxis protocol.

Day of Surgery. One hour prior to surgery: Scopolamine patch 1.5 mg applied behind the ear Zofran 4 mg IV Oxycodone hydrochloride 10 mg po Celecoxib 400 mg po Acetaminophen 1,000 mg po Lansoprazole 20 mg po 500 cc bolus lactated Ringer's IV Postoperatively while in hospital: Zofran 4 mg IV q 8 hours x 24 hours Continue scopolamine patch for 72 hours Combined acetaminophen and hydrocodone 7.5/325 mg, 1 tablet po q 6 hours Acetaminophen 500 mg po q 6 hours Celecoxib 200 mg po bid Lansoprazole 20 mg po qd Hydrocodone prn

After discharge: Combined acetaminophen and hydrocodone 7.5/325 1-2 po q 6 hours Celecoxib 200 po bid for 2 weeks

REGIONAL BLOCKS A slightly different protocol is used when utilizing regional block anesthesia. Studies have demonstrated the efficacy of using regional blocks, such as the CFI, and sciatic nerve blockade to help relieve the pain of TKR. In addition, the use of regional anesthesia has also demonstrated reduced rates of PONV.7,8 Our current protocol uses CFI with a single-shot sciatic nerve block with sedation to complete the TKR. However, by avoiding neuraxial or general anesthesia, the risk of PONV is greatly reduced. Therefore, we do not use the scopolamine patch or the scheduled postoperative Zofran in these patients. The rest of the protocol is the same.

The dosage of the regional blocks is as follows: Preoperatively, the femoral nerve blocks are instituted with a preoperative injection of 15-20 cc of mepivacaine and 15-20 cc of 0.5% bupivacaine. A perineural catheter is placed, and then a CFI is started postoperatively. For CFIs, we use ropivacaine 0.2% at 6-12 cc/h.

The one shot sciatic nerve blocks utilize a combination of medicines, with 15-20 cc of 2% mepivacaine and 15-20 cc of 0.5% bupivacaine. This provides rapid onset and long duration for this block.

In healthy patients under 65 years old, we began using this regional anesthesia technique in May 2004 in an ambulatory surgery center setting, utilizing a 23-hour stay protocol, for total knee replacement. Patient health status is maximized prior to surgery. Hemoglobin must be greater than 13.5 as well. Home health services are utilized, including physical therapy and nursing, to monitor progress the first few days after surgery. All patients have a preoperative visit with our athletic trainer the week before surgery. This session is done to fit the patient with their brace and to teach ambulation in the brace. After surgery, the CFI is maintained for 4 to 5 days. During this time, the patient wears the hinged knee brace when up-ambulating to protect against falls due to weakened quadriceps, which, along with analgesia, is an effect of the CFI.

To date, we have done 50 total knee replacements with this 23-hour-stay protocol. Our su
rgical technique uses an abbreviated median parapatellar approach without everting the patella. This approach is familiar, safe, and easily extensile. Our complications include one transfer to the hospital on postoperative day 1 for therapy issues and one heel blister, which healed uneventfully. We had no VTE complications, and no nerve complications related to the blocks.

This regional block technique can also be used in the inpatient setting. The CFI is removed the morning of postoperative day 2, and the patient usually goes home that afternoon or on postoperative day 3. Bracing is not routinely necessary when they are in the hospital, as therapists and nurses are readily available to assist the patient. The perioperative pain management protocol outlined above is still utilized, but PONV is much less of a problem, and so the scheduled antiemetics are not used, but rather only as prn medications. Use of these regional blocks in the elderly can help limit the utilization of postoperative narcotics, especially morphine, possibly preventing confusion in the early postoperative period.

In summary, postoperative pain management for joint replacement has become perioperative pain management. Protocols such as the ones described in this article help reduce pain and PONV, improve patient vigor, and increase patient satisfaction. Regardless of the surgical approach used for the hip or knee replacement, these types of protocols can be beneficial for patients. Debate will continue about the effectiveness of MIS surgery, but improving pain management is something we all can, and should, do for our patients.

Orthopedic Technology Review. Vol 8 NO 1. January 2006

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