In this blog, we are going to walk through ACL reconstruction. What is the knee comprised of you ask? The tibiofemoral joint (knee joint) is a hinge joint with primary motion in the sagittal plane allowing for flexion and extension (bending & straightening). The knee does have some secondary motions like tibial internal and external rotation, but these accessory motions are hard to control and oftentimes lead to injury. Regional interdependence describes dysfunction at one point in the kinetic chain resulting in abnormal loading or dysfunction at another. Plain and simple, the knee is the “middle man” between the hip and the foot/ankle complex, dysfunction at either can lead to breakdown or injury.
Dysfunction at the hip, specifically gluteus medius weakness, leads to neuromuscular control deficits during dynamic movement. This ultimately results in an increased rate in femoral adduction and internal rotation couple that with an increased pronation moment at the foot and you’ve got a recipe for disaster. This force couple puts an immense amount of stress on the anterior cruciate ligament which has a primary function to stabilize the knee and check the anterior or forward translation of the tibia.
Essentially when the mechanical stress exceeds the threshold of the passive stabilizer (ACL) and the active stabilizer (muscle) isn’t strong enough to make up the difference the tissue gives way. If this is the case, best-case scenario, we end up with an isolated ACL tear. It is not uncommon to experience the terrible triad which is a multi-ligamentous injury to the ACL, MCL (medial collateral ligament), and the medial meniscus. This is due to common insertion points and structural makeup to prevent specific forces.
Most ACL injuries are non-contact, meaning there is no direct blow to the knee. Female athletes ages 13-17 are most commonly affected. There are multiple predisposing factors that increase the likelihood for ACL tears in this population which we lump under “Neuro-Hormonal-Biomechanical influences”. The fact that we know and understand these things allows us to implement injury prevention strategies to help mitigate the risk for traumatic injury.
When ACL reconstruction surgery is deemed necessary if there is meniscal involvement the surgeon will debride (cut-out) the portion of the meniscus that is torn and suture it down to the tibial plateau. When ACL reconstruction takes place there are multiple options to choose from based on patient goals and activity level. The first is will the ACL graft be an autograph meaning from the patient’s own body or will it be an allograft meaning a donor from a deceased body.
After that determination is made the surgeon will decide what tendon, yes tendon, will be harvested from to create the new ACL. Options include the quadriceps tendon, semimembranosus tendon (hamstring), patellar tendon, and tibialis anterior tendon. These tend to be the most common choices. Tunnel holes will be created in the femoral condyle as well as the tibial plateau and the graft will be fixated via an interference screw which over time will calcify with the bone.
After ACL reconstruction, the real fun starts! Getting back to where you were before you were injured or even better than you were. Just like with most surgeries, there will be a time and criteria-based progression to allow appropriate healing. Early milestones of importance include restoring full flexion and extension ROM and regaining full quadriceps strength. This will ensure stability with a normal gait and a post-op brace will no longer be needed. Once that has been achieved you will go through a gradual progression of exercises to build core, glute, quadriceps/hamstring strength.
The focus will shift toward neuromuscular control (eccentric based control) with functional movements like squatting, lateral step downs, and single-leg Romanian deadlifts. The biggest post-op challenge and question is, “When can I run?” Running progression can start typically as early as 4 months but typically between 4-6 months and again is based on criteria. Normal return to sport typically takes between 10 months on the early side, extending to the 1-year mark and beyond.
In a 2019 study, Spindler and colleagues found patients are able to perform sports-related functions and maintain a relatively high knee-related quality of life 10 years after ACL reconstruction.
ACL reconstruction surgery is a minor setback for a major comeback! At the Rehab Docs, we treat our patients as whole human beings and not as individual parts. Therefore, we focus on finding and treating the root causes not just masking the pain. Contact us today to learn more or schedule an appointment.