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.
EconomicsOne 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.
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.