CATHERINE FISCELLA, MSPT
The Knee JointV
Anatomy, common injuries and postrehab strategies.
Knee injuries are among the most common complaints of individuals involved in sports and fitness activities. This is not surprising, since the knee is a weightbearing joint that must withstand large forces–sometimes, as in running and jumping, double and quadruple an individual’s body weight. This article will look at the anatomy of the knee, some common injuries, treatments typically used by healthcare professionals, and postrehabilitation strategies that personal fitness trainers (PFTs) can implement in their training programs.
Joint Capsule. This capsule encloses
Proximal Factors Patellar Position. The patella sits too high
the tibiofemoral and patellofemoral joints to increase stability.
The Patellofemoral Joint
The patellofemoral joint slides superiorly (up) when the knee extends and inferiorly (down) when the knee flexes. A slight amount of medial and lateral deviation, as well as tilting, takes place during normal movement. The following structures help stabilize the patellofemoral joint. Lateral Femoral Condyle. This rounded aspect of the distal end of the femur acts as a bony block to limit lateral motion during knee flexion. Retinacular Tissue. This tissue, which is found medially and laterally, statically stabilizes the patella.
(patella alta) or too low (patella baja) anatomically. Muscle Imbalance. The ratio of the vastus lateralis to the vastus medialis is imbalanced, resulting in increased lateral gliding with patella movement. Rather than moving up during knee extension, the patella moves out to the side and rubs on the femoral condyle. Soft-Tissue Constraints. Distal ITB tightness results in lateral pulling of the patella.
Distal Factors Increased Pronation and Rigid Cavus Foot. Poor foot posture and/or a rigid high
arch of the foot can result in changes in the kinetic chain of the lower extremity.
The knee joint functions as a stabilizer for the lower extremity during weight bearing and allows large range of motion for various functional activities. The two primary articulations of the knee joint are the tibiofemoral joint and the patellofemoral joint.
The T ibiofemoral Joint
The tibiofemoral joint moves in the sagittal plane to flex and extend, and in the transverse plane to rotate when the knee is bent. The following structures help stabilize the tibiofemoral joint: Ligaments. Ligaments connect bones to other bones and prevent excessive movement and dislocation. The medial collateral ligament, lateral collateral ligament, anterior cruciate ligament and posterior cruciate ligament all support and stabilize the tibiofemoral joint. The iliotibial band (ITB) also helps support the knee to limit internal rotation of the tibia on the femur. Menisci. The lateral and medial menisci add depth to the joint surface, thereby aiding in stability. They also serve to distribute load more evenly across the
The following muscles all act at the knee joint to flex, extend and rotate the knee: Extensors: quadriceps femoris (rectus femoris, vastus medialis, vastus lateralis and vastus intermedius); tensor fasciae latae. Flexors: hamstrings (biceps femoris, semitendinosus and semimembranosus); popliteus; gracilis; sartorius. Internal (Medial) Rotators: semimembranosus; popliteus; pes anserinus (semitendinosus, gracilis, sartorius). External (Lateral) Rotators: biceps femoris (possibly aided by the tensor fasciae latae as the knee moves into flexion).
PATELLOFEMORAL PAIN SYNDROME
The treatment chosen by the physician, physical therapist or athletic trainer depends on the cause of the PFPS. Orthotics may be prescribed to address a biomechanical foot dysfunction, or pain may be resolved by strengthening the vastus medialis and stretching the shortened ITB and hamstrings.
One common knee injury is patellofemoral pain syndrome (PFPS). Clients may complain of symptoms when the knee is bent–for example, with stair climbing, squatting and sitting. A healthcare professional will take a clinical history and perform a physical exam to determine the cause of the pain or dysfunction, which may result from proximal or distal factors.
January 2005 IDEA Fitness Journal
Once a medical professional has determined that the patient is ready for postrehab, a PFT can implement the following program: Strengthening. Strength training should focus primarily on the vastus medialis. Potential exercises include the following: