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Dr. Robert LaPrade: Next Steps to Improve Posterolateral Knee Outcomes

by Elizabeth Hofheinz, M.P.H., M. Ed.

The renowned Robert LaPrade, M.D., Ph.D. an orthopedic surgeon with Twin Cities Orthopedics in Edina, Minnesota, has published over 500 peer-reviewed scientific manuscripts during his career, 48 of which have been on the posterolateral knee.

Musing about the “Dark Ages” of knee surgery, Dr. LaPrade told OSN, “A mere 20 years ago, the posterolateral corner of the knee was called the ‘dark side of the knee.’ It was the era of Star Wars and we just didn’t have much quantitative anatomic data, there were no anatomic-based reconstructions, and there was a high rate of clinical outcome failures. And the nonanatomic posterolateral reconstructions that were attempted often resulted in recurrent increases in varus gapping and significant overconstraint in external rotation.”

A desert of knowledge=opportunity

“When I was interviewing for a fellowship in 1992, directors were saying that the most intractable condition to treat was a posterolateral corner injury. So I decided on a program where I could undertake research on this condition, namely, the Hughston Clinic. When I began looking at this topic, the anatomy was not well defined, nor were the biomechanics. The surgical options were either a sling procedure which overconstrained the knee or a primary repair. In most situations, the postoperative technique involved wearing a cast for six weeks, which meant that the knee became stiff or the repair stretched out over time. Not only was arthrofibrosis an issue, but unaddressed  posterolateral corner injuries were often leading to failure of anterior and posterior cruciate ligament (PCL) reconstruction grafts.”

“When I began practicing, I noticed that few surgeons were performing posterolateral knee repairs or reconstructions that were placed anatomically. At the time I saw that the nonanatomic-based reconstructions were stretching out. When we performed our quantitative anatomy studies, we found out that there was an average 18.5 mm distance between the popliteus tendon and LCL attachment sites on the femur. I immediately felt that one graft placed on the femur could not possibly reproduce the function of these two separate structures.”

“It turns out that we as a profession up to that point in time were not putting the grafts in the right place, especially on the femur. We compared a variety of techniques looking at different graft locations on the femur and found that the grafts placed anatomically functioned the best. I felt that we all knew that an ACL graft placed up to 2 cm away from its anatomic attachment site would not work well and felt that had to be the same for the nonanatomic- versus anatomic-based graft placement for the posterolateral knee. That is how we arrived at our anatomic-based posterolateral knee reconstruction technique way back in 1999.”

Nearly 20 years…

“Along with colleagues, almost 20 years ago I developed an anatomic reconstruction that put the grafts where they normally attach (an anatomic-based reconstruction). I recently met with a patient who underwent this surgery in 2002 and her reconstruction had remained in perfect condition. My colleagues and I came to the conclusion that it wasn’t necessary to postoperatively cast patients and that they could move immediately after surgery. We demonstrated that with an anatomic reconstruction and early motion that stress x-rays showed objectively that patients recovered  very well. In addition, we found that with early motion that the grafts did not stretch out.”

Move it, move it

“When I used to run into colleagues at meetings, I often would hear from the podium, ‘You should immobilize these patients for a couple of weeks or your grafts will stretch out.’ But these were the same surgeons who are getting arthrofibrosis in up to 30% of their patients because they were sitting in extension too long. My team and I demonstrated that with early motion our stress x-rays at two years showed that they fared better both subjectively and objectively. Our rate of arthrofibrosis was much less than 5%.”

So where is the room for improvement now?

“Overall, we have made giant strides in treating posterolateral knee injuries…now it is a matter of going from an A to A+. In the past, satisfactory outcomes were 60%…in college that is a D. Now they are 95%. However, we need to polish and refine these anatomic-based techniques and bring postop rehabilitation protocols up to date. Whereas these cases used to take up to two hours to perform, with a good working knowledge of its anatomy, one can perform this surgery in 15 minutes. There has been more progress…up until about three years ago everyone who had been saying that the grafts would stretch out suddenly began promoting range of motion exercises on day one, as well as immediate rehabilitation, which we had been promoting for over 20 years now.”

And on the research front, he commented to OSN, “We need to ensure that future outcome studies have both patient-reported outcomes and objective data with stress radiographs. The next biggest step to improve on our outcomes will be on improving postoperative rehab. In order to prove that very early weight bearing leads to better functioning without causing the posterolateral knee grafts to stretch out will require Level 1 data, i.e., randomized controlled trials that are properly analyzed.”

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Elizabeth Hofheinz

Two time winner of the MORE award Ms. Hofheinz was the first writer employed by Orthopedics This Week. The MORE award is granted annually by the American Academy of Orthopaedic Surgeons to recognize excellence in journalism. Ms. Hofheinz is currently the Director of Communications for Ortho Spine Partners (OSP).

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