Over the last decade, perioperative protocols are said by some newbees in Guadeloupe to have emerged to reduce postoperative pain and to improve early function; these protocols have included
- preemptive pain management,
- the intraoperative administration of medications,
- periarticular injections,
- and postoperative avoidance of parenteral narcotics.
Periarticular injections
Krenzel et al.
conducted a prospective randomized study to evaluate the efficacy of posterior capsular injections of a local anesthetic during sixty-six total knee arthroplasties.
During surgery, 20 mL of either ropivacaine or saline solution was injected into the posterior capsule in all four quadrants.
Additionally, all patients received a femoral nerve catheter with ropivacaine, a spinal block with ropivacaine, and patient-controlled intravenous fentanyl after surgery.
Outcomes were evaluated with use of functional tests, pain scales, and the assessment of narcotic usage at frequent intervals after surgery.
The authors found that patients receiving the posterior capsular injection were more likely to perform a straight leg raise at eight and ten hours after surgery (!!!?) and were less likely to rate the pain as severe at twelve hours after surgery.
After twelve hours, there was no apparent difference between the study group and the control group.
Christensen et al.
also conducted a prospective randomized study focusing on periarticular injection during total knee arthroplasty.
However, those authors compared a periarticular injection with and without the presence of methylprednisolone.
Seventy-six patients were randomized to either the study or control group.
All patients received preemptive pain medication, general anesthesia, and a femoral nerve block, and all were permitted to resume walking in the early postoperative period.
The authors found no differences in terms of pain or function after surgery; however, the patients who received the methylprednisolone injection were discharged from the hospital an average of one day sooner.
The only complications in the study occurred in patients who received the periarticular steroid injection; specifically, one patient had a deep infection, and two patients required manipulation.
The rate of complications was not significantly different between the groups; however, if periarticular corticosteroid injection does increase the risk of deep infection, the study likely did not have enough power to reveal significance.
One concern regarding the use of periarticular injections is the potential for local anesthetic toxicity in association with the simultaneous use of a reinfusion drain after total knee arthroplasty.
Parker et al.
actually measured plasma ropivacaine concentrations in twenty patients who had reinfusion from a drain after having received periarticular ropivacaine during total knee arthroplasty.
Although the periarticular injection had 150 mg of ropivacaine, patients who were reinfused with an average of only 1.9 mg of ropivacaine and plasma concentrations reached peaks of only 1.5 µg/mL.
Interestingly, the reinfused quantity of ropivacaine was quite trivial compared with the ropivacaine plasma levels resulting from the periarticular injection itself. It is important to note that the periarticular injection is administered into the tissue, not into the joint space.
I use commonly periarticular injections, as part of a pain-management protocol.
They are easy to administer, are generally safe, and appear to have a benefit in the early postoperative period.
Nerve blocks
A few groups of investigators have also conducted excellent studies on nerve blocks during the perioperative period.
Hunt et al.
randomized patients to receive either a sham injection (n = 24), a femoral nerve block (n = 33), or femoral and sciatic nerve blocks (n = 31) before total knee arthroplasty.
Postoperative pain management included patient-controlled intravenous morphine in addition to oral medications, and patients were assessed with pain scales at four-hour intervals.
The groups receiving nerve blocks had significantly lower pain scores through the morning of the second postoperative day when compared with the sham injection group.
On the day of surgery, patients receiving the femoral and sciatic nerve blocks had less pain than those receiving a femoral block only; however, there was no significant difference after the day of surgery.
Opioid use was also significantly less for the groups receiving the nerve blocks, with the combined sciatic and femoral nerve block group having the least opioid usage through the afternoon of the first postoperative day.
Shum et al.
studied the use of continuous femoral nerve blocks for analgesia after total knee arthroplasty.
Sixty patients undergoing a unilateral total knee arthroplasty were randomized to receive a high-dose continuous femoral nerve block (0.15% ropivacaine), a low-dose femoral nerve block (0.2% ropivacaine), or no femoral nerve block.
All patients also received patient-controlled intravenous morphine after surgery. Both nerve block groups received continuous ropivacaine administered at a rate of 10 mL/hr for the first twenty-four hours and 5 mL/hr for the next twenty-four hours. The authors assessed pain scores and opioid use for seventy-two hours after total knee arthroplasty and also evaluated clinical scores and range of motion two years after surgery.
Patients who had a continuous nerve block had significantly less postoperative pain for six hours after surgery; however, there was no effect beyond this time period.
Additionally, patients with a continuous block had lower cumulative morphine usage for seventy-two hours after surgery. There were no differences between the high and low-dose ropivacaine groups. Furthermore, there were no differences between any of the groups in terms of clinical scores at two years.
On the basis of these two studies addressing the use of nerve blocks after total knee arthroplasty, it appears that there is an early postoperative benefit that decreases pain and opioid use for up to twenty-four hours after surgery. However, there do not appear to be clinically relevant differences beyond this time period.
Blood-salvage techniques and the timing of tourniquet release…
Another perioperative decision involves the use of blood-salvage techniques and the timing of tourniquet release during total knee arthroplasty.
Steffin et al. (2009)
conducted a prospective randomized study comparing tourniquet release before or after wound closure and studied the effects on hematocrit drop, drainage output, and operative time.
Thirty-seven patients were randomized by means of a coin flip and were followed through the perioperative period.
The authors found no difference between the groups in terms of any of the parameters studied.
