Three Sports Injury Studies

This month we will look at three studies that attempt to answer questions on specific sports injuries and how they affect athletes.

• What is the long-term prognosis for patients with Achilles tendinopathy?

   

• What is the incidence rate for concussion in high school and collegiate football players, and what are the factors that relate to concussion and return-to-play decisions?

   

• Can a preseason training program reduce the number of lower extremity injuries in female soccer players?

Paavola M, Kannus P, Paakkala T, et al. Long-term prognosis of patients with Achilles tendinopathy: an observational eight-year follow-up study. Am J Sports Med 2000;28(5):634-642.

Several common scenarios inevitably occur when dealing with runners. One provides a suggestion to the runner concerning the prognosis of an Achilles tendon problem. Certainly, the distinction between an insertional tendinopathy versus a pure tendinopathy has led to some speculation about evaluation and management. However, the distinction between the histopathological changes of a peritendinitis versus a tendinosis seems to have questionable correlation to clinical signs and symptoms. Further complicating the prognosis prediction is whether findings on palpation, such as tenderness, nodules or swelling, have any bearing on future pain or dysfunction.

This current study takes a look at the natural history of tendinopathy (insertional tendinitis was excluded whenever it was identified). Following 83 patients over eight years gives a glimpse into some possible characteristics of the long-term status of Achilles tendinopathy patients. Although the distinction between "conservative" versus surgical is made, it is also made clear that conservative measures include a variety of inconsistently applied therapies, including: nonsteroidals; intravenous injections of heparin; local corticosteroid injections; and strength and flexibility exercises, among others. With this limitation in mind, 29 percent of patients went on to surgery, while the remainder opted to not have surgery. For all patients, 84 percent had a full recovery (i.e., back to pre-injury activity level). Ninety-four percent were asymptomatic or had mild pain with strenuous activity.

Not surprisingly, 41 percent of patients developed overuse symptoms in the uninvolved Achilles tendon. Although long-term follow-up demonstrated mild to moderate changes with ultrasonagraphic examination and tenderness and nodules were often found, these findings were poorly correlated to pain or dysfunction. It will be important to determine in future studies who is more likely to require surgery, what types of "conservative" care are most effective, and perhaps develop a better distinction between those at risk for bilateral involvement.

Guskiewicz KM, Weaver NL, Padua DA, Barrett WE Jr. Epidemiology of concussion in collegiate and high school football players. Am J Sports Med 2000;28(5):643-650.

Studies have indicated that the incidence of concussion in high school football was 2.8-3.6 percent, and for collegiate football, 4-4.8 percent annually. This study indicates that the incidence may be higher. The researchers also attempted to identify some of the epidemiological factors related to concussion. There are several categorizations schemes for concussion in use. This study used the Cantu concussion rating scale:

• Grade 1 - no loss of consciousness (LOC) and memory loss less than 30 minutes
  
• Grade 2 - LOC less than 5 minutes and memory loss between 30 minutes to 24 hours
  
• Grade 3 - LOC more than or equal to five minutes and memory loss more than or equal to 24 hours

Other rating scales are more conservative (i.e., more likely to prevent an athlete from continuing to play and more likely to send them off for neurological or special imaging evaluation). The following statistics are based on questionnaires sent to high school and collegiate athletic trainers.

The incidence of concussion at the high school level was 5.6 percent; at the collegiate division III level, the incidence was 5.5 percent. Players who sustained one concussion during the season were three times as likely to sustain a second injury. About 60 percent occurred during games. The most common injury mechanisms were:

• Contact with an opponent = 64 percent
  
• Contact with a teammate = 17 percent
  
• Contact with the ground = 10 percent
  
• Contact with equipment = 4 percent

When contact with the ground was the mechanism of injury, 18 percent were on artificial turf (82 percent on natural grass). However, when injury did occur on artificial turf, 22 percent resulted in grade II concussion (versus nine percent on natural grass). The most common symptoms after concussion were headache (86 percent), dizziness (67 percent), and confusion (59 percent). Over 30 percent of players returned to play on the same day of concussion. Of those players, 14 percent had sustained a grade II concussion. Of those who returned to play, they were withheld from competition for an average of 13 minutes. For those who did not return to play on the same day, those sustaining grade I concussion were restricted from playing an average of four days; those with a grade II were restricted eight days on average. Although most decisions were made jointly by the team physician and athletic trainer at the collegiate level, few high school games had a physician in attendance, therefore, the decision was more often made by an athletic trainer.

Heidt RS, Sweeterman LM, Carlonas RL, et al. Avoidance of soccer injuries with preseason conditioning. Am J Sports Med 2000;28(5):659-662.

The injury rate in soccer for females is thought to be twice that of males. There are many factors that have been suggested, most notably that of conditioning. This study compared the injury rates of a group of female soccer players that were given a protocol called the Frappier Acceleration Training Program.¹ This combines sports-specific cardiovascular training; plyometrics; and coordination and strength training. The program was followed for seven weeks by one group of high school female soccer players (42 out of a group of 300), while the control group did not follow this training method. All athletes were followed through two separate seasons. All injuries reported were of the lower extremities, and 61 percent occurred at the knees or ankles. The injury rate for trained athletes was significantly lower than for the untrained group (14 percent versus 34 percent). Although there was also a lower rate of anterior cruciate injury in the trained group, it was not statistically significant.

Reference

1. 1. Swanson SC, Caldwell GE. An integrated biomechanical analysis of high-speed incline and level treadmill running. Med Sci Sport Exerc 2000;32:1146-1155.

Thomas Souza,DC,DACBSP
San Jose, California
souzata@earthlink.net