Pain under the knee when bending is a common concern for many individuals. This discomfort, often felt during actions like squatting, climbing stairs, or sitting for extended periods, impacts daily life. Understanding its origins is key to management. Underlying issues range from mechanical problems to joint inflammation.
Common Reasons for Pain
Patellofemoral pain syndrome (PFPS), often called “runner’s knee,” is a frequent cause of pain under the kneecap. It typically causes a dull ache around or behind the patella, worsening with activities like running, jumping, squatting, or using stairs. PFPS can arise from overuse, improper kneecap alignment, or muscle imbalances that prevent smooth patella tracking. Pain occurs due to cartilage irritation beneath the kneecap from stress or abnormal movement.
Tendinopathies are another common source of pain under the knee. Patellar tendinopathy, known as “jumper’s knee,” causes pain just below the kneecap. It results from repetitive stress on the patellar tendon, connecting the kneecap to the shinbone. Quadriceps tendinopathy can cause pain above or in front of the knee due to overuse and strain.
Meniscal tears can cause pain under the knee, especially during bending, twisting, or squatting. The menisci are C-shaped cartilage pieces that cushion the knee joint, acting as shock absorbers. Tears can lead to sharp pain, stiffness, swelling, or a feeling of catching or locking. Pain with bending often occurs when the torn fragment is pinched within the joint.
Osgood-Schlatter disease primarily affects adolescents, causing pain and swelling below the kneecap, at the top of the shinbone where the patellar tendon attaches. It is a repetitive strain injury common in young athletes during growth spurts, as physical activity stresses the growth plate. Pain worsens with deep knee bending, running, or jumping, due to the patellar tendon pulling on the growing bone.
Initial Steps for Relief
For mild knee pain, several at-home strategies can provide relief. The RICE method—Rest, Ice, Compression, and Elevation—is a recommended initial approach for swelling and discomfort. Resting the affected knee by avoiding pain-triggering activities prevents further irritation and allows healing. Applying ice for 15-20 minutes every few hours reduces inflammation and pain; wrap ice packs to prevent direct skin contact. Compression with an elastic bandage limits swelling, while elevating the leg above heart level reduces fluid accumulation.
Over-the-counter pain relievers, such as nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, alleviate pain and reduce inflammation. Acetaminophen is another pain relief option, though it does not address inflammation. Topical NSAID gels also provide localized pain relief with fewer systemic side effects.
Gentle exercises strengthen knee-supporting muscles and improve flexibility, but should be performed without pain. Quadriceps sets, hamstring stretches, and glute bridges are beneficial examples. Activity modification, such as avoiding deep squats or prolonged kneeling, can prevent aggravating the knee and allow recovery.
When to Seek Professional Guidance
While many instances of under knee pain improve with home care, certain signs indicate the need for professional medical evaluation. Severe pain preventing weight bearing or significantly interfering with daily activities warrants immediate attention. Persistent pain that worsens despite several days of home treatment should prompt a visit to a healthcare provider.
Significant swelling around the knee, especially if sudden, indicates a more serious injury or infection. Other concerning symptoms include knee instability or “giving out,” inability to fully straighten or bend, or an audible popping sound. Redness or warmth around the knee, particularly with fever, could suggest a joint infection, requiring urgent assessment.
Medical Diagnosis and Treatment
For knee pain, a healthcare provider typically begins with a physical examination and discussion of symptoms and medical history. The doctor assesses range of motion, stability, and tenderness to pinpoint the pain source. They may also ask about activities that worsen or improve pain, and any specific incidents.
Imaging tests may be ordered to evaluate the knee and confirm a diagnosis. X-rays can help rule out bone fractures or osteoarthritis. For a more detailed view of soft tissues like ligaments, tendons, and cartilage, an MRI scan may be utilized. These tests provide insights into structural integrity.
Treatment approaches vary by diagnosis and condition severity. Physical therapy is a common and effective treatment, focusing on strengthening exercises for surrounding muscles and flexibility training. Therapists may guide specific exercises, such as eccentric loading for tendinopathies, to promote healing and improve function. Bracing or taping can provide support and help with kneecap alignment.
For persistent pain, injections may be considered. Corticosteroid injections can reduce inflammation and pain, while platelet-rich plasma (PRP) injections promote tissue healing. In rare cases where conservative treatments are unsuccessful or for severe injuries like certain meniscal tears or ligament ruptures, surgery may be necessary. Surgical procedures range from minimally invasive arthroscopic techniques to more extensive open surgeries, depending on the issue.