Injuries to the anterior cruciate ligament (ACL) of the knee are one of the most common orthopedic phenomena, affecting up to 400 000 individuals each year in the United States alone. This is commonly observed in organized sport activities, especially ones involving dynamic change in direction and speed, such as soccer, basketball, or American football. While the treatment must be individualized and depends on level of activity, age, and patient expectations, most of these injuries are treated with reconstruction. This involves using a person’s own tissue is used to reestablish the stability of the knee.
Certain factors put an individual at higher risk of injury and some of these can be minimized while others are nonmodifiable. While being well described for years in the orthopedic community, female gender is a risk factor that has received a considerable amount of attention in recent years. Females are much more susceptible to ACL tears, almost 5-fold compared to their male counterparts. There are several reasons for which can be stratified as anatomic, biomechanical, hormonal as well as neuromuscular. Females are known to have a smaller ACL and a narrower “notch,” which is an area in the knee where the ligament itself passes through. In addition to having valgus alignment, or being "knock-kneed,” females tend to land from a jump in a more extended position and this mainly due to the uneven muscular recruitment which is more quadriceps dominant, having lower hamstring engagement and weaker core. Some experts have also postulated that the lack of “sport diversification” is to blame for rising incidence, meaning increasing number of adolescents are dedicated to only one sport, in which they participate all year long, as opposed to playing multiple sports throughout the year. This is thought to engage different muscle groups and stress their bodies in different ways.
Most people will require surgery for an ACL injury. If a person desires to return to activities which involve contact sports, change of direction and pace, a reconstruction is required to preserve the stability of the knee. This involves taking a graft from elsewhere in the body and securing it in place where the native ACL was. Common grafts include quadriceps, patellar or hamstring tendon. There are pros and cons to each of these choices, however all have demonstrated to be reliable and durable, with the choice depending on patient and surgeon preference.
The cornerstone of any orthopedic treatment is rehabilitation and ACL injuries are no different in this regard. This is a lengthy process that typically lasts 9-12 months and is paramount to a successful outcome. Rehabilitation is typically done in phases which the patient “graduates from”. The initial phase focuses on flexibility and regaining range of motion, followed by strengthening and finally a phase involving dynamic exercises and real-life loading of the knee. Following a successful rehab, patients are expected to resume all activities, in the same capacity, as they did before the injury. However, a commonly neglected and crucial caveat is ongoing conditioning in years to come, which will maintain longevity and prevent reinjury.
Article written by Ognjen Stevanovic, MD, PharmD