Total joint replacements (TJRs), especially total knee replacements, are among the most painful surgeries. In a preoperative survey of 20 TJR patients at Suburban Hospital in Bethesda, Maryland, most indicated that they expected to have high levels of postoperative pain; postoperatively, this proved to be the case. Pain management in TJR patients is complicated by their age, increased number of comorbidities, and their general deconditioned status before surgery.
Despite the pain, TJR surgery is often the best treatment option for some patients, such as those with advanced osteoarthritis. Surgery not only lessens the pain from their condition, but also increases functionality. So, effectively managing postoperative pain is essential for helping patients achieve the best possible functional outcome.
In this article, we'll look at several pain management options that exist for these patients, including patient-controlled analgesia (PCA), epidural analgesia, intermittent intravenous (I.V.) injections of pain medications, and oral pain medication, both extended-release and short-acting formulations. One option that's usually off limits is nonselective nonsteroidal anti-inflammatory drugs, such as naproxen or ibuprofen, because they can prolong bleeding time. Also, keep in mind that any pain management option must be combined with effective assessment techniques before and during therapy sessions.
Pump away the pain
The PCA pump is a good choice for postoperative pain management in TJR patients. The surgeon prescribes pain medication, such as morphine, hydromorphone (Dilaudid), or fentanyl, which is delivered I.V. through an infusion pump at the bedside. Patients push a button to receive a dose of medication from the pump if their pain level increases. Continuous or basal rates, which deliver a set amount of medication each hour, are no longer recommended with PCA because they contribute little to pain relief and carry the risk of overdose or oversedation.1,2 An added benefit of PCA is that patients commonly feel more satisfied with their pain relief when they use a PCA pump. They can get pain relief when they need it without waiting for pain medication, and they can choose when and how often they use the medication, although a lock-out system is in place so patients can't overmedicate themselves.
On the local front
Using local anesthetic for pain relief, either alone, as in a continuous femoral blockade, or combined with an opioid delivered through an epidural catheter, is another option for pain control after TJR. Epidural catheters can be placed before surgery, used during the operative procedure, and then continued for postoperative pain relief. The length of time the catheters can be used is limited, however, because most TJR patients are started on anticoagulants after surgery, putting them at risk for an epidural hematoma. The patient's international normalized ratio or prothrombin time should be monitored closely while the catheter is in place.
More recently, continuous femoral blockade using an On-Q PainBuster has become popular for pain control (see About the On-Q PainBuster).
Progressing to oral medications
Oral medications are started when patients no longer need the PCA pump or epidural or I.V. pain medications. These medications should be offered regularly for the first few days to promote more consistent pain relief.
Patients who've been using pain medication regularly before surgery may require extended-release pain medication such as oxycodone (OxyContin) or morphine sulfate extended-release capsules (Kadian, Avinza). For most patients, shorter-acting combination pain medications, such as oxycodone and acetaminophen (Percocet) or hydrocodone and acetaminophen (Vicodin, Lortab) may be sufficient to adequately control pain.
Next, let's look at what role physical and occupational therapists can play in minimizing pain while optimizing function in TJR patients.
Once the health care provider has ordered rehabilitation for the TJR patient, physical therapists (PTs) and occupational therapists (OTs) should assess the patient's pain level; social history; home environment; discharge needs; goals; and functional, gait, and strength status. Establishing a pain level baseline is important for gauging pain tolerance and response to activity, such as range of motion (ROM) exercises. It's best to use a pain rating scale of 0 to 10 (0 = no pain and 10 = maximal pain) to assess the pain level. Check for pain at rest and with movement, and then document the findings at the initial evaluation and after each subsequent session to maintain a running record of postoperative pain. A documentation sheet where these results are recorded helps track how the patient is tolerating the therapy.
On the move
As the PT begins to mobilize the postoperative TJR patient with transfer, gait training, and ROM exercises, the results of the pain rating scale will be used during therapy to modulate the intensity of the sessions. Transfers and gait training with an assistive device, such as a walker or crutches, are essential to facilitating independent mobility and allowing for a safe discharge home or to further rehabilitation.
The OT plays a key role in determining what type of devices the patient will need for activities of daily living. The OT is involved in helping the patient transfer from bed to chair in the early postoperative period to ensure that this can be done safely. Mobility training helps ensure safe functional mobility. Movement also increases blood flow, facilitates flexibility of all joints and, in turn, helps decrease postoperative pain levels.
Remember that activity of any type, especially physical or occupational therapy, can dramatically increase pain. Make sure the patient has been premedicated 30 minutes before therapy or that he or she is using PCA with a drug that delivers quick onset of relief. This is the best method to relieve the dynamic pain of movement.
In addition, cold therapy can be applied locally to the postoperative joint to decrease pain. The patient should be educated on the benefits of cold therapy and routines for use of cold packs in managing postoperative pain.
Even before surgery, PTs and OTs play an important role in educating patients about what to expect concerning activity level after surgery. Many hospitals have developed Joint Schools or Joint Camps-patients come to the hospital before their surgery to see what their new joint will look like, and to hear from the staff who will care for them postoperatively.
At these sessions, exercises can be demonstrated or instructional sheets can be handed out to patients so they can see what type of activity is expected. The PT and OT can explain the postoperative exercise regimen and the need to be comfortable enough to tolerate the activity after surgery. This is the time to stress the benefits of early mobilization in the plan of care for rehabilitation. It's an opportunity for the staff to meet patients and make an initial assessment about what level of care will be needed in the rehabilitation period. Some patients with good baseline functioning and home support may be able to go directly home after surgery with home physical therapy services. Other patients who are more deconditioned and have less home support may need a short stay in a rehabilitation center before going home.
Most Joint Schools or Joint Camps have a set schedule for therapy sessions that take place in a large gym area where the whole group of joint patients can interact and watch each other progress. This group process is important in encouraging the patients to follow the plan of care for participating in both physical and occupational therapy. Many patients report that they're very satisfied and encouraged by the group therapy sessions and their interactions with the PTs and OTs.
Easing the pain
Although postoperative pain control can be difficult in TJR patients, the benefits of good pain management on early mobilization is tremendous. The expert assessment skills of PTs and OTs can help patients understand how to move more efficiently and with less pain, contributing significantly to the overall success of the surgical experience.
About the ON-Q PainBuster
The ON-Q PainBuster catheter is placed during surgery at the site of the femoral nerve. The catheter has a soaker hose type of perforation along the end of it, which allows a local anesthetic, such as bupivacaine, to flow directly over the nerve. The result is a dramatic reduction in pain. The local anesthetic is contained in a ball-shaped reservoir and flows at a preset rate, either 5 mL or 10 mL per hour. The medication usually lasts for 48 hours postoperatively. Although the pain sensation is decreased, most patients have no trouble tolerating the local anesthetic and can participate fully in physical therapy.
Photo courtesy of I-Flow Corporation, Lake Forest, Calif.