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Knee Pain Occurrence and Prevention
Part 1: Acute Knee Pain
By Anne C. Terry, RN, MSN, ARNP
As climbers, we may encounter a knee injury sometime in our sporting lifetime. Potential damage to the knee may include an acute injury from a fall while rock climbing, an overuse injury from hiking long distances with a large pack, or in high speed lateral sports a twisting injury to the supporting tendons from sideways movements. The knee involves the center of articulation between the bones of the leg—the femur and tibia--and the patella, a free-floating bone over the anterior knee surface. Known as a synovial joint, the knee has six bursae, or sacs, that are filled with fluid and provide joint mobility. The knee also has two menisci (plural for meniscus), or small cartilage cushions, and four strong ligaments. The knee is classified as a hinge joint, performing predominantly flexion and extension. However, it can also perform both lateral and rotational movements to varying degrees. (1,2)
Below I outline common acute knee injuries and conditions. Acute knee pain may or may not be associated with trauma and involves pain of less than two weeks in duration. Chronic knee pain (to be discussed in January 2004) is often the result of overuse and/or may be precluded by a history of previous knee injury. It is typically gradual in onset and greater than a few weeks in duration. The first part of this article is intended to be informative and is not a substitute for proper medical evaluation.
Acute Knee Pain
- Knee Dislocations
- Ligament Tears
- Meniscal Tears
- Patellar Dislocations
- Prepatellar Bursitis
- Quadriceps or Patellar Tendon Ruptures
Fractures of the knee involve the femur, patella and/or tibial plateau (top of the tibia.) They are often overlooked after an acute injury since attention is drawn to the possibility of a ligament tear. These fractures are often intraarticular, meaning they involve the actual joint space of the knee. Fractures cause sudden pain, swelling, and an inability to bear weight on the affected limb. Fractures of the femur and tibial plateau often involve a fall from a height with the knee in a compromised position. Depending on the severity of the fracture, treatment may simply involve casting. However, more severe fractures will require surgical repair. Fractures of the largest free floating bone in the body, the patella, typically involves direct trauma, such as a fall anterior surface (front of the knee). Patients usually present with pain, swelling and/or bruising over the front of the patella and have increased discomfort with knee extension or straightening the leg. Both nonoperative and surgical treatment options are available. More severe fractures are treated with full leg casting for 4-6 weeks with the leg placed in full extension. (1,2)
Acute dislocation of the knee is a severe injury requiring immediate medical attention. This injury is associated with high-energy injuries such as a fall. Clinically, the knee will often appear deformed. The patient will experience extreme pain, possible swelling, and/or bruising. Vascular injury (injury to the blood vessels) is a potentially dangerous complication of knee dislocation. This type of dislocation generally requires surgical repair. (1,2)
There are four main ligaments in the knee: the anterior cruciate ligament (ACL); posterior cruciate ligament (PCL); lateral collateral ligament (LCL); and medial collateral ligament (MCL). The ACL and PCL stabilize the knee for front and back movements, while the MCL and LCL stabilize against forces to the sides of the knee surface. (1,2,4)
Injury to the ACL is often the result of a quick twisting movement, such as a tight turn in skiing, and results in a sudden “giving way” of the knee and significant pain. Some patients may also experience an audible popping. Tears of this ligament can be either partial or complete and are often accompanied by an injury to the menisci. Acute swelling, instability and pain prevent the patient from being able to continue their activity. Treatment options are decided upon by the patient’s age, the severity of the tear, and any associated injuries. Surgical treatment generally yields high success. Young patients are often able to return to their normal activities. Untreated ACL tears can lead to degenerative arthritis and/or meniscal injuries.
Known as the strongest ligament in the knee, the PCL can become injured in a number of settings, such as hyperflexion or hyperextension, a fall on a flexed knee and/or forces directed towards the back of the knee surface. Pain and swelling usually occur directly after the injury. Some patients may feel that the knee is unstable. PCL tears can often be treated nonoperatively with quadriceps strengthening. However, these tears often occur with additional ligament damage and may require surgery.
MCL and LCL
Injuries to the MCL and LCL are generally the result of injuries to the knee from the outside or inside of the knee surface. Patients report acute pain, stiffness and swelling of the knee, but are often able to continue playing their sport. They report pain over the inside or outside of the knee along the joint line. Treatment of this type of tear is generally nonoperative, since motion of the knee can be performed with other ligaments intact. Significant tears may involve damage to other structures in the knee surface and also may require surgery.
Damage to the medial and lateral menisci are often the result of a sudden twisting motion and may occur with or without ligament damage. After the injury, patients are often able to continue participation in their activity. Most commonly, pain is noted over the outside or inside of the knee surface and is associated with swelling. Full knee motion may be limited as a result of pain. Depending on the severity of the tear, some meniscal injuries can be treated with conservative management, such as rest, elevation, ice application and use of anti-inflammatory medications like NSAIDs (Non-steroidal anti-inflammatory agents). Examples of NSAIDs include advil, motrin and aleve, and are available over the counter. NSAIDs should be used with caution since they have the potential to cause gastrointestinal, liver and/or kidney complications. Please consult with your primary care provider with additional questions regarding anti-inflammatories. Severe meniscal tears, particularly in the young athlete are often treated with surgery. (1,2)
The patella, or kneecap, can be displaced in acute injury by a fall on the knee surface or a blow to the knee, such as in rockfall or slipping on rough ice or scree. Injury to the surrounding soft tissue and damage to the ligaments holding the patella in place cause pain, fluid collection in the joint, bruising, and reduced range of motion. Most patients report a sudden pop with pain and/or swelling. They may also notice asymmetry in kneecap appearance and the feeling that the knee is “giving way.” Depending on the severity, patellar dislocations often reduce, or are put back in position, spontaneously. A single dislocation may predispose the patient to recurrence. (1,2)
Quadriceps and Patellar Tendon Ruptures
Acute rupture of the quadriceps and/or patella tendons results in pain, swelling and loss of the ability to extend the leg. Typically, this occurs as a result of a fall on a partially flexed knee. In compensation, the extremely strong quadriceps muscle may overcome the strength of these associated tendons. Patients are often unable to walk immediately following such an injury. Complete tears must be repaired surgically and are often associated with fractures of the patella. (1,2)
This inflammatory and/or infectious condition is often the result of an acute injury to the anterior knee surface or can become a chronic condition resulting from prolonged kneeling. Patients with this condition will notice pain and swelling of the patellar bursa, a small sac located between the patella, or kneecap, and the outlying skin. An infectious bursitis produces a more pronounced area of pain, swelling and redness and is often the result of a small scab or wound on the knee surface becoming infected with bacteria. Treatment of an inflammatory bursitis involves rest, immobilization and use of NSAIDs. Infectious bursitis is also treated with immobilization, as well as antibiotics, often given intravenously. (1,2,4)
This is the first in a three-part series on knees. Knee injuries can happen to any active outdoor enthusiasts, particularly those who participate in high force activities such as skiing, snowboarding and jumping sports, climbing, and sports involving lateral or sprinting movements such as soccer, rugby, football, basketball and lacrosse. This month Annie Terry, RN, MSN, ARNP, and climber with the Seattle Mountaineers, has joined us to discuss acute (sudden onset) knee pain including ligament strains, meniscal tears and patellar dislocations. In January (see Part 2 www.bodyresults.com/e2kneepain2.asp) we will take a look at chronic knee pain associated with overuse. February will feature a series of sport-specific free weights leg exercises and stretches that will help you recover from and prevent future recurrence of knee pain.
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- Spence, A. Basic Human Anatomy. pp. 160-170.
- Vad V, Hong HM, Zazzalit M, Agi N, Barai D. Exercise recommendations in athletes with early osteoarthritis of the knee. Sports Med 2002; 32 (11): pp. 729-39.