I have written about knee injuries so much. Every day we are bombarded with research that quite frankly, it gets boring. The problem is with approximately a quarter-million ACL injuries per year, it is safe to say the injury is rampant. The devastating nature and commonality of the injury has provided loads of information on prevention, rehabilitation and mechanisms of injury. I am not going to regurgitate them all, but do want to share some recently published articles that sports medicine experts should read.
Article 1: Negahban, Et al. A systematic review of postural control during single-leg stance in patients with untreated anterior cruciate ligament injury. Knee Surgery Sports Traumatology and Arthroscopy, May, 2013.
I love systematic lit reviews and this SLR aimed to determine postural control on those with ACL injuries. We have many internal systems and senses that help us balance. Beyond the use of our eyes and ears to sense balance, tiny mechanoreceptors and proprioceptors exist in our tissue that sense abnormal movement. This study found that when the eyes are closed individuals with ACL injuries had increased postural sway and loss of balance. This indicates that the injury and inflammation following injury inhibits our body’s internal mechanism to sense balance. When rehabilitating, be sure to emphasize proprioception exercises.
Article 2: Thomas, Abbey, et al. Lower Extremity Muscle Strength After Anterior Cruciate Ligament Injury and Reconstruction. Journal of Athletic Training published online first, 2013.
Despite advances in rehabilitation and the numerous studies published on ACL rehabilitation protocols, we appear to be failing. This study shows that at 6 months Status Post ACL reconstruction that global weakness still exists. When comparing strength output from injured vs. uninjured legs it appears the knee-extensors (quads) and knee flexors (hamstrings) are weaker at 6 months when compared to the contralateral side. Conversely hip and ankle strength was not significantly different at 6 months. The timeline to return a player back to competition and activity is 6 months following activity and/or 95% strength of the uninjured side. This study indicates 6 months might be too early. Also, we may need to adjust our strengthening protocols to further stress knee flexion / extension strength.
Article 3 – Bell, DR, Clark, MA, Padua, DA, et al., Two- and 3-Dimensional Knee Valgus Are Reduced After an Exercise Intervention in Young Adults With Demonstrable Valgus During Squatting. Journal of Athletic Training published online first, 2013.
Darin Padua and the UNC Department of Exercise and Sport Science has done a lot of work on knee displacement and correlating the findings with ankle hypomobility and hip underactivity. This particular model used the NASM Corrective Exercise Model as the intervention procedure. This method systematically turns off hyperactive tissue and activates hypotonic tissues. The data revealed that following intervention of the ankle and hip medial knee displacement was significantly reduced. This information is important as several studies have shown medial knee displacement to be a primary cause of ACL injuries and chronic knee pain.
Article 4: Ericksen, et, al. Different Modes of Feedback and Peak Vertical Ground Reaction Force During Jump Landing: A Systematic Review. Journal of Athletic Training published online first, 2013.
The inability of the body to absorb and control joint movement during high levels of ground reaction forces has been shown to increase risk of ACL injury as well as other chronic knee conditions. This study evaluated the effect of expert provided and self-analysis feedback reduced peak ground reaction forces. This is not a paramount study but does shows the effectiveness of verbal queuing and observation to correct suboptimal neuromuscular control, specifically during landing and absorption of ground reaction forces through the kinetic chain. Rehab practitioners should incorporate feedback to teach clients appropriate muscle control during ACL rehabilitation.
I would like to say thank you to Darin Padua, PhD, ATC for keeping me abreast with current data. Darin is a leader in sports medicine research and specifically has many published papers on ACL injuries. Darin manages his blog site and also shares info on his twitter account. If you are a health and wellness professional seeking important information rehabilitation and prevention of injury, I recommend you give Darin a follow.