Dr. William Barrett’s Blog

At the recent American Academy of Orthopaedic Surgeons 75th annual meeting in San Francisco, California, the use of partial knee replacement was reviewed. Unicompartmental or partial knee replacements have been around for quite some time. They can be utilized for typically the medial compartment or inside compartment of the knee and also for the patellofemoral joint.

Manufacturers are now looking a combining a partial knee with a patellofemoral replacement in an attempt to replace two out of the three compartments sparing the uninvolved third compartment. Whether or not these partial replacements will equal or exceed the results of total knee replacement remains to be seen. Ten year plus results of unicompartmental replacement from a variety of centers have shown excellent results and are a reasonable option for that group of patients (10%), who are candidates for partial knee replacement. While partial knee replacement is an attractive alternative, it at times can be a more challenging procedure. Patients considering this should ask their surgeon how experienced they are in this type of procedure, as it is certainly less common than total knee arthroplasty.

There were several papers at the recent American Academy of Orthopaedic Surgeons meeting in San Francisco, California March 2008, discussing the use of metal-on-metal hip replacement. There have been reports in the literature outing a delayed hypersensitivity-type reaction. The incidence of this os felt to be very low, but the extent of potential problem is not completely known. Some studies haver reported this while other centers have had a extremely low rate of metal-on-metal allergic-type reaction. While this is certainly a possibility, it seems that the instance at most center is very low. We have extensive experience with metal-on-metal articulation in total hip replacement and have seen a very low incidence (less than 1%) of allergic-type reaction. Each combination of bearing surfaces and total hip replacement brings its own pluses and minuses and you should discuss these with your orthopedic surgeon. 

We are presenting a paper at the 75th annual meeting of the American Academy of Orthopaedic Surgeons, outlining risk factors associated with infection after total knee arthroplasty. A review of over 5800 total knees, done at seven centers across the United States, revealed that patients who are obese (Body Mass Index greater than 30) have a significantly increased risk of infection after total knee arthroplasty. Furthermore, patients with a Body Mass Index greater than or equal to 35, classified as highly obese, had an even greater risk of infection following total knee replacement. Obesity increases the risk of surgical complications as a result of more difficult exposure, longer operative time, prolonged wound drainage, due to the thick layer of adipose tissue which is present between the skin and the deeper tissue, leading to the higher risk of wound complications and infection. It is important that individuals who are overweight work to try and maximize their health prior to surgery and strategize on how to keep their weight as reasonable as possible. There is strong evidence that obesity leads to an increased risk of developing arthritis in the knee and in fact, in our study 55% of the patients were in fact obese at the time of surgery.

There have been many changes in the doctor patient interaction over the last two decades. With increasing demand for patient’s time, office visits have been shortened and grouped closer together. This often leads to longer wait times, shorter face to face time with the physician and increased interaction with physician’s assistants. In an effort to more accurately document what happens and create a more permanent record, many offices are moving to digital x-rays and electronic medical records. Our office began using distal x-rays approximately five years ago and we have been very excited with the outcome of this. It provides faster delivery of images, a more permanent record, and a more transferable image. The quality of our x-rays has increased significantly and allows us to give copies of x-rays to patients after their office visit.

In an effort to meet increasing governmental regulation, we are converting our medical records to an electronic medical record. This allows better record keeping, greater access to information for documentation purposes, but will change the nature of the interaction with the patient. Instead of listening and dictating the interaction at a later date, often data will be inputted into a tablet, a personal computer, at the time of the office visit, which will alter the way that we interact with patients. This may create a somewhat impersonal interaction, but probably will become the wave of the future. It will also change the way patients interact with physicians’ offices. Appointments and appointment forms will be downloadable from the internet and many of the information can be completed and electronically sent back to the office, decreasing the amount of time spent filling out paperwork in physician’s offices. Change is inevitable and our job is to try and embrace new technology and use it in a way that allows us to provide better care, better record keeping, and allow us to accommodate an increasing number of patients that is inevitable as our baby boom generation continues to age.

Analysis of the incidence of total hip and knee replacement over the next 20 years, as baby boomers reach retirement age, anticipates a six fold increase in the number of knee replacements done by 2030 and a doubling of the number of hip replacements. In 2016 there will be over 572,000 hip replacements and 3.5 million knee replacements performed. In 2005, 7% of the American Academy of Orthopaedic Surgeons identified themselves surgical specialists for adult hip and knee replacement. The number of adult joint reconstruction surgeons is decreasing while the number of patients requiring joint replacements is significantly increasing. This added to the fact that from 1991 to 2007 there has been a 40% decrease in reimbursement for hip replacement while during that same period there has been a 49% cost of living increase, is creating a challenging environment for joint replacement surgeons to continue to undertake the increasing volume of patients as we go forward over the next 20 years.

At a paper presented at the American Association of Hip and Knee Surgeons, at Dallas, Texas, a study from the Mayo Clinic asked patient’s their perception of function after hip resurfacing versus standard total hip replacement. The majority of patients felt that hip resurfacing was a safer procedure, required less soft tissue damage to perform the procedure, and they would get back to activities more quickly. While these perceptions are not supported by any data, this study underscores how patient perception can influence postoperative result and anticipation of what procedure would be best. Rather than base decisions on perceptions or unfounded claims on the internet, it is best to discuss the pros and cons of different types of hip operations with your orthopedic surgeon to make sure you make a knowledgeable informed consent.

At a recent meeting of the American Association of Hip and Knee Surgeons in Dallas, Texas, a paper was presented that reviewed a series of revisions of knee replacements done by five surgeons at three different centers. The group of patients who had had a minimally invasive total knee replacement had a much higher rate of failure in less than12 months, 37% versus a more standard approach 5%. From reviewing this data it appears that the use of minimally invasive total knee replacement can account for a substantial increase in revision of total knees particularly at less than 12 months after surgery. This trend merits further evaluation and underscores the importance of properly aligning and placing the knee replacement and not sacrificing long-term results for a shorter skin incision.