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Knee News

Issues in Adult Reconstructive Knee Surgery

Total knee replacement, or total knee arthroplasty is an increasingly common surgery. The authors of this article describe various issues involved in knee reconstruction, including economic, surgical and demographics. To do this, researchers reviewed 100 medical journals to ultimately find the outcome of 6,483 patients who had undergone knee replacements.

One study, by Bhattacharyya and colleagues looked at the success of pay-for-performance. They found that teaching hospitals, hospitals with higher volumes of replacement surgeries and hospitals in the Midwestern part of the United States had better pay-for-perfomance rate. The performance was judged on three issues: when antibiotics was started before surgery (preoperatively) and if it was done within one hour, when antibiotics were stopped after surgery (postoperative and if it was within 24 hours of surgery, and if there were signs of bleeding, bruising, or chances that the patient would need to be readmitted to the hospital.

Another study, however, by Bozic and Chiu that also looked at pay-for-performance, found that surgeons varied widely as to whether they stuck to certain guidelines, such as timing of x-rays before surgery, timing of referral for surgery, use of injections and physical therapy, and repeat operations after one year. Finally, a third study by Rosenberg and colleagues looked at the timing of when antibiotics were started before the surgery. To ensure that patients received the antibiotics, the institution studied used a 'time out' protocol, which aimed to ensure that the timing of the antibiotics was adequate. In other words, the incision for surgery would not be made until a certain amount of time had passed since the patient received the antibiotics. The authors of the study found that this time-out period improved antibiotic guideline adherence from 65 percent to 97 percent within 18 months.

Unicompartmental Arthritis

When arthritis affects one part of the knee, rather than the whole knee, this is unicompartmental arthritis. This is a common reason for knee replacements. In one study, Riddle and colleagues looked at the data from three different implant manufacturers and how often these implants were used in 44 hospitals. They found that over a seven-year period (1998 to 2005), the rate of implant use increased by an average of 32.5 percent. In comparison, there was a 9.4 percent increase in total knee replacements over that same period.

Another study that used the Swedish registry to look at knee replacements, done by Robertsson and Lidgren, looked at the short-term results of three different unicompartmental knee replacements. They found that there was a less than 10 percent risk of having a revision surgery after five years, but one particular type of implant needed revisions more than the other two.

A 12-year study, done by Emerson and Higgins, looked at 55 knees over the course of 12 years following unicompartmental knee replacement. They found an revision rate of 85 percent. Interestingly, there have been excellent long-term reports for this type of surgery, but there have also been many early failures due to mechanical breakdown. To study this aspect, Aleto and colleagues looked at 32 knee replacement revisions on patients whose average age was 66 years at the time of the revision and there was an average of 5.7 years between the initial surgery and the revision surgery. Fifteen failures were due to a collapse of the medial tibial plateau, the smooth bony surface of the two bones that join at the knee. The patients who had this complication ended up needing more screws or other hardware when their knee was replaced by a total knee replacement. As well, these patients were generally older than the others. They were, on average, 71 years old while the others were an average of 61 years old.

As with most other procedures, there are various approaches that surgeons may use to accomplish their goal. Recently, surgeons have been focusing on trying to reduce tissue damage, reduce pain after surgery, and improve the speed with which a patient may regain full - or as close to full as possible - function.

One approach, called the midvastus involves making an incision into the joint (arthrotomy that moves away from the kneecap, to the middle of the quadracep muscle. Dalury and colleagues investigated this approach in 20 patients who had both knees replaced; one knee was done this way and the other using another approach. The results of their study showed that there was not much difference between the two knees six weeks after the surgery. Six patients did prefer the midvastus approach, but no other issues were noted.

Another approach, the mini-subvastus approach has similar results but the surgeon can avoid cutting into the quadraceps muscle and tendon. Schroer and colleagues looked at 150 total knee replacements to assess the success of this approach. They found that patients who had the mini approach were discharged from hospital earlier than patients who had the traditional approach. They were able to recover their quadriceps strength more quickly, were less likely to need inpatient rehabilitation, and had better ability to bend the knee.

Minimally invasive surgeries, those that don't make such large incisions as traditional surgeries, are becoming more common as surgical equipment becomes more advanced. Researchers McAllister and Stepanian looked at the early results of 100 patients who had total knee replacements, either with minimally invasive surgery or traditionally. Their results showed that the patients with the minimally invasive surgery had shorter hospital stays, less complaints of pain, and better bending than those who had the traditional surgeries. However, after one year, there were not many differences between the two groups.

Computer Use
Computer navigation is becoming increasingly popular in surgery. With knee replacements, computer navigation allows the surgeons to line up the bones more accurately, improving the chances of the implant success. In one study, by Lionberger and colleagues looked at 46 total knee replacements during which the surgeons used a navigation system. After surgery, 95 percent of the patients had accurate lining up of the bones and mechanical limb alignment was 93 percent.

During Surgery
Perioperative, during surgery, management has also been improving over the years. Pain management and patient education have also significantly improved outcomes after knee surgery. Dorr and colleagues studied 35 patients who had an epidural anesthetic and 35 who had a femoral nerve block (local anesthesia), along with pain medications after surgery. The patients were encouraged to take medications before they were absolutely necessary. These patients seemed to have better pain relief than those who are managed with traditional pain relief techniques. This type of pain relief also reduced the need for narcotics.

Another researcher, Lavernia and colleagues, looked at 778 procedures where patients were managed with traditional pain relief techniques and compared them with 358 patients who followed a specific pain-management protocol. The protocol included using the medications celecoxib, controlled release oxycodone, acetaminophen, and ondansetron. These medications were given in such a way that the pain was prevented, rather than treated. The patients also received the same local anesthetic described above. The results were not surprising. Those patients who prevented the pain did better after surgery than those patients who managed the pain once they felt it.

Blood Clots
Venous thromboembolism, blood clots in the deep veins in the leg, are a common problem among many patients who undergo surgery, particularly surgery in the hips and knees. There are treatments to try to prevent it, but this is controversial among some surgeons for patients who undergo total knee replacements. Researchers Novicoff and colleagues looked at patients who received a new protocol of anti-coagulation therapy, medications that prevent the formation of blood clots. All patients who had a total hip replacement received warfarin to thin their blood and those who were considered to be high risk for developing a clot received a higher dose.

As with all medications, anticoagulants may cause side effects and the researchers found that this was no different. In this study, there was a 1.4 percent increase in bruising and hemorrhages from before the protocol was instituted. That wasn't all. Readmission to hospital increased by 2.2 percent and there was no change in the number of patients who developed blood clots.

Another study, done by Callaghan and colleagues, looked at 312 total knee replacements, in which low-risk patients were given aspirin to try to prevent blood clots. In this study, there were no side effects noted and no readmissions to hospital.

As with all surgeries, total knee replacements do cause complications for some patients. Pulido and colleagues investigated in-hospital complications in 15,383 joint replacement in patients who had either a knee or hip replacement. They found a 0.16 percent mortality rate in the hospital. Complications involving body systems, systemic complications, included 152 blood clots that went to the lungs, pulmonary emboli; 92 rapid and irregular heart beats, tachyarrhthmias; and 36 heart attacks.

When looking at the joints, the researchers found 29 injuries involving the nerves around the joints, 25 fractures of the replacements; 18 dislocations; and 16 injuries to the blood vessels around the joints. Another researcher, Parvizi, found that 0.7 percent of 4,567 patients studied developed postoperative ileus, complications in the colon.

Infections are always a risk after surgery and knee replacements are no different. In a study by Kurtz and colleagues, it was found that those patients who had a total knee replacement had a higher rate of infection (0.92 percent) than patients who had a total hip replacement (0.88 percent). Having an infection doubled the length of hospital stay among patients with the replacement.

Carl A. Deirmengian, MD, and Jess H. Lonner, MD. What's New in Adult Reconstructive Knee Surgery. In The Journal of Bone and Joint Surgery. Dec. 2009.  Vol. 91-A. No. 12. Pp. 3008 to 3018.


*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.
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