An Australian physical therapist (they are called physiotherapists down under) won The American Journal of Sports Medicine’s annual competition in 2009. It was for the best systematic review with meta-analysis on the subject of leg injuries in athletes who are hypermobile.
Let’s back up a bit and explain a few things. First, what’s the big deal about the competition? Well, a systematic review involves sifting through 1000s (4841 to be exact in this study) of studies on a particular topic. Meta-analysis means the researchers had to find studies that were similar enough in data collection and analysis that the results could be pooled together.
In the case of this review, no one had ever performed a meta-analysis and all previous systematic reviews had not been able to answer the question. And what was the question again? Are athletes with generalized joint hypermobility (GJH) more likely to injure knees and/or ankles compared with sports participants who have “normal” joint motion.
Generalized joint hypermobility (GJH) is defined as a condition in which most, if not all, of a person’s joints are super flexible. They move past the range of motion that the normal, average person has. This type of connective tissue flexibility is sometimes referred to as being “double jointed”.
The person really only has one joint at each location. It’s just that those joints move too far, too easily. Sprains, strains, subluxations (partial dislocations), and complete dislocations are common. It seems like athletes with generalized joint hypermobility (GJH) actively involved in sports injure the joints of the legs more often than those players who don’t have GJH. But does it just seem that way or is it a true observation?
The results of this systematic review with meta-analysis suggest there is a direct link between GJH and leg injuries. One of the challenges the authors faced was the fact that most of the studies they found only looked at one type of leg injury (just the knee or just the ankle). There was very little information on hip injuries (only one study and only three hip injuries).
There was a wide range of athletes included from ballet dancers and divers to military recruits and football players, the last group was from the college and professional level. Some of the injuries were from contact activity with high-impact collisions (with another body or with the ground). Others were from overuse (e.g., diving, dancing). Overall, there were significantly more injuries among the contact or collision sports participants.
As for the joints injured most often — that distinction goes to the knees. Individuals with generalized joint hypermobility (GJH) were much more likely to injure the knee (much moreso than the ankle) compared with athletes who had normal joint motion.
These findings are consistent with what other studies show about ankle injuries — namely, that loss of ankle motion is the key risk factor in ankle injuries (not hypermobility). Likewise, when it comes to knee injuries, when the foot is planted on the ground and the body twists or rotates above, the lack of restraint on the knee joint in someone with GJH contributes to knee injuries. Without stiff ligaments, there’s no tension keeping the joint from sliding too far.
So whether it’s ballet or grid iron, male or female, amateur or professional, there is an increased risk of leg (knee) injury among people with generalized joint hypermobility. No recommendations were made based on these findings. Just coming to some conclusions about this issue based on a systematic review and meta-analysis is a major step forward in sports orthopedics.