Should weekend warriors worry about a patellar tendon injury?

As most sports fans can attest to, Victor Cruz sustained a very painful and devastating knee injury in the third quarter of the Eagles/Giants football game earlier this month. As a sports medicine physician watching the game with a group of friends and passionate football fans, I became the target of a barrage of questions and concerns regarding this injury. Quickly it became quite clear that the level of concern in the room was unexpected.

The first question from virtually everybody watching the game was "What happened?" The reason for the confusion was that the replays did not really demonstrate much of an injury mechanism. It was a non-contact injury and it appeared that Victor Cruz was doing something that he had done probably hundreds of times before in similar settings. Based upon the video it would have been almost impossible to predict that a patellar tendon rupture did occur. Once the type of injury was confirmed, the next question I faced, particularly from the more athletic of the group in attendance, was "how could this happen to a 29 year old professional football player?"

Victor Cruz was doing an activity that did not appear much different than what any other athlete had done numerous times during sports such as football, basketball, volleyball, or even jumping to catch a baseball. It became evident to me that the concerns of these weekend warriors was not so much with Cruz's future, but rather the overwhelming concern was "could this happen to me?"

Patellar tendon anatomy is relatively straightforward. The patellar tendon is a ropy structure that lies in front of the knee and attaches from the bottom of the kneecap to the top of the tibia. The patellar tendon along with the quadriceps tendon are essential components to allow an individual to straighten their knee. A patellar tendon tear is a rare injury occurring in less than 0.5% of the U.S. population per year, most commonly in men. The mechanism of injury occurs following a sudden quadriceps contraction with the knee in a flexed position as would be seen in jumping sports. Less commonly a patellar tendon can tear following a fall if there is a direct impact to the front of the knee. Unfortunately complete tears of the tendon result in an inability to straighten the knee and, therefore, these injuries must be fixed surgically.

Patellar tendon ruptures tend to occur in athletes age 40 and younger and in older individuals who have risk factors such as diabetes or lupus or rheumatoid arthritis. There is also a separate category of individuals who are predisposed to tendon rupture because they have had prior injuries to the patellar tendon that have caused some internal damage, or individuals who have had prior injections to the patellar tendon. Taking anabolic steroids to increase performance can also weaken the tendon and increase the risk of rupture.

Athletes will know immediately that there is an injury because they will feel some type of ripping sensation and will be unable to ambulate because of weakness and pain. They will also be unable to actively straighten out their leg. These injuries are relatively easy to diagnose simply by physician or trainer examination. X-rays are used to rule out fractures of the patella or tibia and MRIs are useful in diagnosing partial tears.

There is a thought that healthy normal patellar tendons should not tear, particularly with the type of mechanism that was seen in 29 year old Victor Cruz's situation. There was nothing unusual about his particular play that would have led anyone to think that that injury could have occurred. Therefore, that does beg the question as to whether or not there was some prior damage to the tendon that he may not have been aware of. It also arises a suspicion that there could be possibly have been some association with steroid usage as well. Clearly I have not seen any information whatsoever to suggest that Victor Cruz had ever taken any type of anabolic steroid, but given the mechanism of injury that occurred, it is a question that would be asked of every athlete in a similar situation regardless of who that athlete is.

While Victor Cruz is not the only NFL player to experience this type of injury, it does not occur very often. A 2011 study in the American Journal of Sports Medicine noted that knee injuries were relatively common among professional football players, but ruptures of the patellar tendon were actually relatively rare. Between 1994 and 2004, 24 patellar tendon ruptures were noted in NFL football players. Eleven of the football players had some symptomatology prior to the injury. The most common mechanism of injury was a lengthening contraction of the extensor muscles. Three of the football players also tore their anterior cruciate ligament at the same time, but the majority of players only had the patellar tendon injury.

So the bottom line is that this study shows that patellar tendon ruptures can occur in healthy football players who did not have pre-existing symptoms or predisposing factors. On the positive side though, surgical repair generally produced good results that allowed these athletes to return to professional or high-level football.

Knowing that the level of concern in the room after this injury was not altruistic, but rather mediated by personal fear, I did advise these weekend warriors that they had a far better chance of tearing their ACLs and their meniscii and developing arthritis than tearing their patellar tendons. For greater validation, I was speaking not only as a sports medicine surgeon, but a member of the ACL club, the meniscal club, and the arthritis club!

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