There are several factors that can affect knee joint stability which can be crucial for a healthy joint. The knee relies on 4 major ligaments to maintain the stability of your joint – the ACL (anterior cruciate ligament), PCL (posterior cruciate ligament), MCL (medial collateral ligament) and the LCL (lateral collateral ligament). In addition to the major ligaments, other components that help maintain joint stability are the shape and alignment of the bones (bow legged versus knock-kneed), the integrity of the meniscus and the intact cartilage surfaces (loss of cartilage=arthritis). Injury from direct or indirect trauma can tear or rupture one or multiple ligaments creating instability in the joint.
The most commonly injured ligament in the knee is the ACL, which usually tears from an uncontrolled deceleration. For example, football, soccer, hockey, skiing and other sports in which players are moving quickly and then forced to slow down or stop in an uncontrolled fashion can often lead to torn ACL’s. Ligaments can be repaired, usually arthroscopically, using grafts from other parts of the knee. Many patients are able to return to their previous level of function after completing the appropriate rehab program.
Your kneecap (patella) also needs to glide properly in the “knee groove” for the joint to function normally. Patella malalignment or instability can often feel like your knee cap is slipping or dislocating out of the natural groove of the knee. Sometimes, people are born with abnormal alignment or have a knee groove that is too shallow, allowing the kneecap to dislocate. In other cases, patella malalignment can also be caused by trauma or from overuse. Patellar realignment surgery brings the kneecap back into normal alignment. This can be achieved by adjusting the tension of the ligaments and muscles on either side of the patella, creating a deeper groove with an implant or by moving the bone to one side where the patella tendon attaches to the shinbone.
If your leg alignment is abnormal (varus-bowlegged or valgus-knock kneed) then a High Tibial Osteotomy can be performed. The majority of knee osteotomies are performed on the tibia. For example, someone with abnormal alignment that has there too much stress on the inside or outside of the knee can be straightened so the force is more evenly distributed across the joint. This is achieved by taking a wedge of bone out of the shinbone, straightening the leg and then fixing the shinbone in place with screws and a plate. Alternatively, a larger bone wedge can be inserted to prop up the bone, like a shim, in order to bring the leg back into normal alignment. It takes approximately 1 year for the new bone and alignment to heal but the HTO procedure can be very effective and last a long time.
Each year, more than 100,000 ACL reconstruction procedures are completed with approximately 1/3 of those having associated knee problems such as malalignment. Are you experiencing any of the symptoms of knee malalignment?