Currently, the majority of these decisions are based on the most current and up to date information we have available. Or is it? Considering that most use a Biodex to make this decision, does an open kinetic chain strength test (Biodex) really tell us anything about how stable the limb is in closed kinetic chain conditions, in running, landing or cutting situations? Adduction in the frontal plane is a risk factor and hip strength plays a big role in. Does this test give an indication of hip strength? Is there a better way to assess frontal plane motion?
Considering the following scenario. Athlete who is testing for return to play and is tested on a Biodex. She tests to be within 90% of the non-involved limb. But this poses several questions. 90% of what. Is that 90% of good strength which adds to good quality movement or is that 90% of poor strength and quality of movement? Secondly, does this open kinetic chain test truly reflect closed kinetic chain function. I think once we see this, we can all clearly see she is at risk, but how do we quantify that?
Over the last couple of years, several papers have attempted to look at just that. In some of our previous blogs we cited McCullough et al who published a MOON study in 2012 that looked at return to sport following ACL reconstruction. What they showed was that 63% of high school players and 69% of college players were able to return to sport following ACL reconstruction. They also showed that only 43% of those athletes were able to return to the same level of sport as prior. In this case, return to same level of sport was defined as same level of pre-injury performance as self-reported by the athlete. Similar studies have attempted to do this in NBA players. Harris et al published a paper in 2013 that looked at the impact of ACLR on future performance in fifty-eight NBA players. Performance was measured by comparing pre-injury data to post injury data in the following areas: games per season played, minutes played, points & rebounds per game and field goal percentage. Several interesting findings came out of this study including 40% of the players who tore their ACL during a game, did so in the fourth quarter. 86% of players returned to the NBA and 12% of players returned to the FIBA or D-league. 98% of the players that returned to the NBA and 3% had revision of their ACL. Performance upon return to sport following surgery declined significantly for all subjects. However, this was not statistically significant when compared to controls during this same time period. Busfield et al 2009 also investigated this in NBA players. They looked at 27 NBA players who had ACLRs. Of those, 22% did not return to the NBA and 78% did return to play. Of the 78%, 15% had an increase from pre-injury performance and 44% had a significant reduction from pre-injury performance.
- Performance is negatively impacted by injuries and with return to sport. This highlights the importance of directly measuring the pre/post performance variance.
- The fact that over 40% tore their ACL in the fourth quarter tells us that fatigue plays a significant role. This highlights the importance of considering this in the assessment with return to play.
- The fact that speed position players were 4.0 times less likely to return to play may indicate the impact that injury has on power output. Since these positions are so dependent on explosive power and agility, you would expect that if injury does have a big impact on performance that these positions would be the most significantly impacted.