Our knees are the largest joints in our bodies. They’re the most complex, highly used, and vulnerable tools of our anatomy, bearing our weight and carrying us where we need to go. From bending to extending and rotating, these joints are active participants in most day-to-day activities. Taking on the amount of force they do throughout the day, it’s no surprise that knee pain is one of the most common complaints among patients of any age.
Beyond the simple daily activities that strain these joints, such as going up and down stairs, bending to pick something up, and sitting or standing, most sports and exercises put additional stress on the lower body. In fact, knee injuries make up as much as 55% of all sports injuries. The joints’ complexity allows them to move in wondrous ways but also makes them susceptible to injuries unique from other joints.
The three bones that join together at the knee, the tibia, femur, and patella, are linked by tendons and cushioned by cartilage. Unless gliding together perfectly, the repeated strain on the anatomy can cause runner’s knee, fractures, tears, or various other ailments.
Whether caused by a serious injury or a minor ache, point-of-care ultrasound (POCUS) serves as a convenient tool to assess knee pain. Without transporting the patient, POCUS-trained orthopedists may use the bedside tool to rapidly evaluate the severity of the injury and determine a proper way forward.
Despite the name, runner’s knee can affect even those who don’t run. The term refers to multiple conditions that cause pain around the kneecap, all caused by misalignment of the patella. When the kneecap moves improperly, it may rub against the lower part of the thigh bone, causing pain when walking, running, or sitting for long periods. The condition may occur due to overuse, poor running posture, or weak hamstrings or quadriceps. As the knee bends, the muscles on either side of the leg pull the patella. An imbalance in the strength of these muscles can cause patellar misalignment.
Pain from the injury should be treated with rest, ice, compression, and elevation (RICE). To remedy the condition, practitioners may recommend running shoes with increased arch support, continued rest, extended warm-ups prior to exercise, and physiotherapy to strengthen the necessary muscles and realign the patella.
Some clinicians may choose to diagnose runner’s knee using only medical history and physical exam, but imaging may be necessary to rule out other, more serious injuries. Other common knee ailments include tears and strains of the anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL), meniscus tears, fractures, and dislocation. Symptoms of these injuries are similar: a popping sensation, sudden swelling, stiffness, pain, and instability. All are common athletic injuries, each caused by an improper bend or rotation of the knee.
Because of their similar symptoms and the need to assess severity, imaging is essential to diagnosing these pathologies. Surgery may be required to repair the damage caused by tears or fractures, but most dislocations and sprains can be approached noninvasively with RICE to reduce pain and swelling and physiotherapy to strengthen the joint and surrounding muscles.
Using POCUS as the initial diagnostic tool allows clinicians to rapidly assess the status of the joint. Though magnetic resonance imaging (MRI) provides a deeper picture of the anatomy, ultrasound is quick and cost-effective. It offers beneficial initial insight at the bedside or on the field.
The knee is vulnerable. Pain may be caused by overuse, underuse, or unavoidable sources such as age, arthritis, or structural abnormalities. The joint and the muscles around it must be strong enough to bear our weight under the pressure of everyday life to keep pain to a minimum and discourage major or minor injuries. Every bone and ligament in our bodies are connected. If one muscle is weak, the others must compensate, leading to strains and tears. Every cog of the machine must push and pull in unison, or we put ourselves at risk of injury and the need to sacrifice our favorite activities.
By showing our bodies the respect they deserve, they may continue carrying us throughout the day.
Interested in learning more about the countless benefits POCUS provides orthopedists and their patients? The Point-of-Care Ultrasound Certification Academy™ provides additional insight into the improvements POCUS can make to musculoskeletal health.