THE KNEE
| The knee joint is formed by three bones: The tibia, the femur, and the patella (knee cap). These three bones are held together by various ligaments and tendons, allowing the knee to bend and straighten for sitting, walking, and other activities. All three bones are lined with articular cartilage, with is a smooth layer over the bones to allow normal gliding of one bone over the other. Also, the knee joint contains a medial and lateral meniscus, both of which act like shock absorbers in the knee and help contour the femur to the tibia. Finally, the stability of the knee joint is enhanced by four major ligaments: 1. The anterior cruciate ligament (ACL); 2. The posterior cruciate ligament (PCL); 3. The medial collateral ligament (MCL); and 4. The lateral collateral ligament (LCL). Other structures critical to knee function are the patellar tendon, quadriceps tendon, hamstring tendons, the iliotibial band, and medial patellofemoral ligament (MPFL). | |
KNEE SWELLING
Knee swelling is not a condition in itself but a sign of injury to one of the many structures that form the knee. Swelling inside the knee capsule itself is known as an “effusion.” A knee effusion can be painful and can limit motion and is an indication that something within the knee joint itself is injured. This could be a ligament, a meniscus, the cartilage lining, an infection, a fracture, or some other less common reason.
ANTERIOR CRUCIATE LIGAMENT (ACL) INJURY
Injury to the ACL is a very common injury, typically occurring in active individuals. The injury can occur from contact sports, non-contact activity, or by trauma. The ligament serves to provide stability to the knee joint and a torn ligament can result in pain, swelling, and difficulty walking. Over time, patients may suffer from episodic pain and instability of the knee. Injuries to the meniscus and cartilage lining are common injuries that occur with ACL injuries. Long term problems with an ACL deficient knee include further damage to the meniscus, further cartilage lining damage, and arthritis. An ACL injury can be diagnosed by office examination supplemented by an MRI scan of the knee.
Depending on age and activity level, surgery may be recommended to reconstruct the ACL. The ACL cannot usually be surgically repaired and needs to be replaced with graft tissue. The surgery is typically done using a minimally invasive arthroscope. Physical therapy is needed after the procedure and patients can return to full activity in 6-9 months, depending on graft selection and concurrent injuries.
POSTERIOR CRUCIATE LIGAMENT (PCL) INJURY
Injury to the PCL is an uncommon injury, typically occurring in active individuals. The injury can occur from contact sports, non-contact activity, direct blow to the front of the knee, or by trauma. The ligament serves to provide stability to the knee joint and a torn ligament can result in pain, swelling, and difficulty walking. Over time, patients may suffer from episodic pain and instability of the knee. Injuries to the meniscus and cartilage lining are common injuries that occur with PCL injuries. Long term problems with a PCL deficient knee include further damage to the meniscus, further cartilage lining damage, and arthritis. A PCL injury can be diagnosed by office examination supplemented by an MRI scan of the knee.
Depending on the extent of the PCL injury, surgery may be recommended to reconstruct the PCL. The PCL cannot usually be surgically repaired and needs to be replaced with graft tissue. The surgery is typically done using a minimally invasive arthroscope. Physical therapy is needed after the procedure and patients can return to full activity in 6-9 months, depending on graft selection and concurrent injuries.
MEDIAL COLLATERAL LIGAMENT (MCL) INJURY
The medial collateral ligament is the most commonly injured ligament of the knee. It is located on the inner aspect of the knee. The MCL can be injured by contact or non-contact mechanisms. Injury to the MCL results in pain in the inner aspect of the knee, swelling, and difficulty walking. A MCL injury can be diagnosed by office examination supplemented by an MRI scan of the knee. MCL injuries usually do not require surgery. However, surgery may be recommended for high grade MCL tears.
LATERAL COLLATERAL LIGAMENT (LCL) INJURY
The lateral collateral ligament is a less commonly injured ligament of the knee. It is located on the outer aspect of the knee. The LCL can be injured by contact or non-contact mechanisms. Injury to the LCL results in pain in the outer aspect of the knee, swelling, and difficulty walking. A LCL injury can be diagnosed by office examination supplemented by an MRI scan of the knee. Depending on the extent of injury and other concurrently injured structures, surgery may be recommended for an LCL injury.
MENISUS INJURY (MEDIAL MENISCUS AND LATERAL MENISCUS)
The medial meniscus and lateral meniscus serve as shock absorbers of the knee and help contour the femur to the tibia. They also serve to protect the articular cartilage lining of the knee. The meniscus can be injured with an acute injury or with gradual wear and tear. Meniscus injuries can result in pain over the inner or outer aspect of the knee, depending on which meniscus is injured. Also, patients can present with pain, swelling, and clicking/popping of the knee. Meniscal injuries that are displaced can occasionally cause locking of the knee. A meniscus injury can be diagnosed by office examination supplemented by an MRI scan of the knee.
Depending on the type and extent of the meniscal tear as well as other concurrent knee problems, surgery may be recommended to treat the meniscal injury. Meniscal injuries can be treated with surgical repair versus partial removal of the meniscus. This is typically done with a minimally invasive arthroscopic procedure. Physical therapy is needed after the procedure and patients can return to full activity in 1-6 months, depending on the extent of the tear and whether the meniscus was repaired or partially removed.
CARTILAGE INJURY
The smooth surfaces of the femur, tibia, and patella are known as the articular cartilage lining of the knee. They allow easy gliding of one bone on the other to facilitate movement of the knee joint. Injury to this cartilage lining can occur with contact or non-contact injury to the knee as well as by trauma. Symptoms of cartilage injury include specific pain over the site of injured cartilage as well as swelling of the knee joint. The cartilage can be injured by itself or along with a bony fracture beneath the cartilage. Cartilage injury in the knee can be diagnosed by office examination supplemented by x-ray and MRI scans of the knee. Depending on the extent of cartilage damage, surgery may be recommended for repair or reconstruction. There are several cartilage restoration techniques, and the surgeon will discuss with you which are appropriate for each specific injury.
PATELLAR INSTABILITY
The patella normally slides over the front of the femur with bending of the knee. For various reasons, the patella can dislocate out of this normal position. The patella typically dislocates laterally. Patellar dislocation can occur with trauma, non-contact knee injury, or spontaneously due to abnormal bony and soft tissue anatomy. Patellar dislocations can spontaneously reduce or may need to be reduced by a health care professional. Patellar dislocations result in pain, swelling, and difficulty walking. A patellar dislocation can be diagnosed by office examination supplemented by x-ray and MRI scans of the knee.
Patellar dislocations can be treated non-operatively in a special brace. However, surgery may be recommended for recurrent dislocations. Surgery involves reconstructing the medial patellofemoral ligament as well as possibly other surgical procedures such as realigning the bone to which the patellar tendon attaches to prevent further dislocation.
KNEE ARTHRITIS
Knee arthritis is usually a condition of wear and tear of the cartilage lining of the knee. Arthritis can occur in only one area of the knee or can be throughout the entire knee. Arthritis is thought to be accelerated by obesity and prior injury to the knee. Symptoms of knee arthritis include pain, swelling, and reduced ability for walking or other activities. Arthritis can be diagnosed by office examination supplemented by x-ray examination of the knee.
Arthritis can be treated in many ways, ranging from physical therapy, knee injections, and surgery. Knee injections come in two varieties. One type of injection is known as viscosupplementation. In this type of injection, gelatinous material mimicking the worn cartilage is injected into the knee to cushion the knee and reduce some of the inflammation in the knee joint. You may know these injections by their trade names: Synvisc, OrthoVisc, Supartz, and Euflexxa, amongst others. Alternatively, cortisone injections can be placed in the knee, helping to alleviate the inflammatory component of arthritis and help with pain symptoms. The longevity of both of these injections is unpredictable but can often result in long lasting symptomatic relief.
Knee arthritis can also be treated with surgery. Depending on the extent and location of the arthritis, there are several surgical procedures available. These range from partial knee replacement, total knee replacement, and osteotomy of the knee (shifting the body weight from the damaged to the more normal part of the knee). Physical therapy is needed after any of these operations and recovery time depends on the surgery performed.
PATELLAR TENDONITIS
The patellar tendon is a structure that connects the patella to the tibia. It is critical for walking and extending the knee. Patellar tendonitis can occur due to overuse, jumping, or chronic wear. Symptoms of patellar tendonitis include pain over the patellar tendon, pain with walking or jumping, and sometimes difficulty walking. Patellar tendonitis is typically diagnosed by office examination and sometimes aided by an MRI scan of the knee.
Patellar tendonitis can most often be treated with physical therapy and oral anti-inflammatory medications. If this first line treatment is unsuccessful, a new injection known as PRP (platelet rich plasma) can be placed into the area of damaged tendon and aid in healing of the tendon. Finally, recalcitrant cases of patellar tendonitis can be treated with surgery.