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High Complication Rate with MPFL Knee Reconstruction

In this systematic review, surgeons from the Department of Orthopaedic Surgery and Sports Medicine at the University of Kentucky found 25 articles on the subject of medial patellofemoral ligament (MPFL) reconstruction. Their interest was in reporting on the various ways to do this surgery and the rate of complications.

This information is important in helping surgeons improve treatment and results for the many athletes who are affected by injury to this ligament. A little bit of anatomy will help explain this injury. Let's start with the patella -- more commonly known as the "kneecap". The patella moves up and down in front of the knee joint along a built-in track called the patellofemoral groove.

The kneecap is held in place by several ligaments on either side and by the patellar tendon (attached to the quadriceps muscle). The quadriceps muscle is the large, four-part muscle along the front of the thigh.

Although you can take your hands and passively move the kneecap from side to side, this is not an active movement you can make your patella do without assistance. We call that side-to-side (medial-to-lateral) movement accessory motion. The up-and-down and side-to-side accessory motions are referred to as patellar glide.

As part of the patellar tendon, there are slips of ligamentous fibers that help hold the patella in place and keep it from moving too far to one side or the other. On the inside of the kneecap is the medial patellofemoral ligament. On the outside is the lateral patellofemoral ligament.

Without the medial patellofemoral ligament, the kneecap dislocates laterally (in a direction sideways away from the other knee). Because the medial patellofemoral ligament is connected with other ligamentous structures, complete rupture will likely damage other areas as well. The medial patellofemoral ligament attaches above to the femur (thigh bone) and below to the tibia (lower leg bone).

When this ligament is torn, surgery to repair or reconstruct it may be needed. But there are many different ways to accomplish this and no one way known to have the best results for everyone. Looking at results reported for different graft choices, graft tension, and fixation methods (ways to attach the graft in place) will help surgeons find better ways to stabilize the knee and prevent a disabling condition for these young athletes.

The choice of articles to review was limited because some reports were just case studies (small groups of patients) while others were done on cadavers (rather than with live patients). Of the studies that qualified to be included, there was a 26.1 per cent complication rate. The procedure was a success but the complication rate was considered significant. This figure represents an overall complication rate from all the studies combined. Rates actually ranged from zero (no complications) up to 85 per cent.

Taking a closer look at the specific complications, there were patellar fractures, patellar instability, loss of knee motion, pain, infection, and other wound complications. Twenty-six of the 629 knees treated surgically required an additional surgical procedure. The most common revision surgeries were to remove bothersome hardware or manipulate (move) the joint to restore motion. Three per cent of the total number were classified as "failures" due to ongoing instability and persistent patellar dislocation.

What conclusions did the authors come to from the results of their analysis?

  • MPFL reconstruction surgery is a popular choice but complication rates following surgery are too high. Caution is advised when this procedure is done.
  • There is a lack of high-quality, consistent research reported on this topic; future studies need to evaluate MPFL reconstruction techniques. Comparisons between different approaches are needed with large numbers of patients.
  • There may be other as yet unknown risk factors for complications after this type of surgery; reasons for complications and failures must be determined.

    The authors concluded their discussion by providing other surgeons with advice and counsel on MPFL reconstruction. They based their comments on their experience and findings in the systematic review. For example, they offered suggestions for the right amount of tension placed on the graft tissue and placement of the graft.

    The surgical treatment techniques presented are meant to stabilize the knee but retain motion. They also pointed out the difficulties reported with different fixation methods (e.g., tunnel versus suture techniques). And they suggested a fixation angle for the graft at less than 60 degrees in order to prevent complications.

    Jay N. Shah, MD, MS, et al. A Systematic Review of Complications and Failures Associated with Medial Patellofemoral Ligament Reconstruction for Recurrent Patellar Dislocation. In The American Journal of Sports Medicine. August 2012. Vol. 40. No. 8. Pp. 1916-1923.


    *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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