Painful Lump Below Knee In Adults: What Could It Be?

Written By on November 10, 2021 — Medically Reviewed By Kristopher Ceniza

Written by on November 10, 2021 — Medically Reviewed By: Kristopher Cenzia

The Osgood-Schlatter disease typically affects children and adolescents. But, about 10% of these cases carry the disease into maturity and it can present as a painful pump below the knee in adults. (1)

Most cases of Osgood-Schlatter in adults improve with home care. Although, rare cases may need surgery to get rid of the pain and other symptoms. Don’t worry, we’ll go over treatments for OSD so you know what to do. (1)

But, what if you didn’t have Osgood-Schlatter as a child? Well, there are 2 common conditions that mimic Osgood-Schlatter disease in adults. We’ll talk about those, too.

First, let’s figure out if it’s a flare-up of Osgood-Schlatter disease:

What is Osgood-Schlatter disease?

Osgood-Schlatter disease is an inflammation of the patellar tendon. It affects the part where the patellar tendon attaches to the shin bone (i.e. the tibial tubercle).

The patellar tendon is also how your quadriceps muscles pull on your leg. Thus, straightening your knee joint.

On the other hand, the tibial tubercle is a growth plate in children and adolescents. So, it’s more cartilage than bone until growth stops.

That said, Osgood-Schlatter disease happens when there’s repetitive pulling on the cartilage. This irritates your tibial tubercle, leading to inflammation and OSD. (1)

Osgood-Schlatter disease can happen during a growth spurt because, sometimes, the muscles can’t keep up with the bone growth. This can cause growing pains and OSD inactive children. (1)

Some athletic activities make kids prone to Osgood-Schlatter disease. Common examples include (1):

Knee Force Knee Sleeve
  • Jumping sports.
  • Skiing.
  • Figure skating.

Causes of Osgood-Schlatter disease in adults

Adults don’t have growth spurts anymore. But, you can still have the condition if the cause of your Osgood Schlatter disease wasn’t addressed properly as a child. Or, more specifically:

  • Your disease went untreated.
  • Your OSD wasn’t treated properly.
  • There are bone fragments in your patellar tendon due to OSD.

A flare-up of OSD can happen in adults that play sports like basketball, volleyball, or running. Running and jumping motions can irritate the tibial tubercle, causing Osgood-Schlatter’s pain.

Symptoms of Osgood-Schlatter disease in adults

The main symptom is a painful inflammation of the tibial tubercle. It can look like a lump under the kneecap, on the tip of the shin bone.

Other symptoms include:

  • Tightness on the thigh muscles.
  • Pain on the affected knee while climbing stairs.
  • Redness in the area.

How to treat Osgood-Schlatter disease?

Osgood-Schlatter disease responds well to conservative treatments. These reduce pain and swelling to let the tendon heal. But, adults with recurrent symptoms may need surgery.

The treatment for children and adults is similar. It includes:

Ice and rest

Applying ice to the area can reduce pain and swelling. You can do this at home with ice packs. Place the pack on the bump for 10 minutes at a time, 2 or 3 times per day.

Also, activity modification is key for your recovery. Resting will reduce the stress on the tendon to let it heal. If you keep doing physical activity during a flare-up, you can worsen your symptoms. (2)

Knee Supports

There are several types of these but the best knee supports for Osgood-Schlatter are the ones that help you manage your symptoms.

Knee straps apply pressure on the patellar tendon, thereby altering its effect on your tibial tubercle and reducing pain.

Compression sleeves help with blood flow, warmth, and proprioception. So they’re great for both prevention and recovery.

Knee braces, particularly those with designs that apply pressure on your tendon while relieving pressure off your kneecaps, are great for adding stability while reducing pain.

Physical therapy

Physiotherapy can speed up your recovery. It can also help you get back into sports activity while preventing Osgood-Schlatter and other injuries.

First, your physical therapist will work on reducing knee pain and inflammation. The treatment may include using heat/cold, electrotherapy, massage, or light exercise to reduce symptoms.

Then, your therapist will address any underlying weaknesses. This is key to prevent Osgood-Schlatter disease. But, treatment won’t always be the same for everyone. (2)

For example, you may need to strengthen your quadriceps muscles. Another person may need to strengthen their hamstring muscles. Some athletes may have to improve their technique to prevent injury.

In any case, a knowledgeable PT can figure that out.

And, if you need help finding a PT in your locality, we can help.


Oral anti-inflammatory drugs can help if you are in too much pain. Your doctor may prescribe them to manage symptoms. If the oral drugs don’t work, your doctor may suggest injecting a local anesthetic into the area. (2)


This is the last resort. Orthopedic surgeons suggest this for people that don’t improve with physical therapy or medication. (2)

Knee Force Knee Sleeve

The type of surgery depends on the severity of your symptoms. Your orthopedic surgeon may have to remove part of the bony prominence and/or the bursa.

Other causes of knee pain below the kneecap

If you didn’t have Osgood-Schlatter disease as a kid, the lump may be due to:

Jumper’s knee

This is also known as “patellar tendinopathy.”

Here, the tendon has micro traumas due to repetitive athletic movements. It’s common in sports that involve running, jumping, or cutting. Like basketball or volleyball, for example. (3)

It has two main differences to Osgood-Schlatter disease (1, 3):

  • Tendinopathy affects the patellar tendon as a whole. OSD only affects the insertion point of the tendon at the growth plate.
  • Tendinopathy can happen to anyone that plays sports but OSD is almost exclusive to children and teens.

Your doctor will make a thorough examination of your lower leg before the diagnosis. If you’re under 18 years old, your doctor may need imaging tests to see your tendon.

Infrapatellar bursitis

A bursa is a small fluid-filled sac. It reduces friction between tendons, muscles, and/or skin. Bursitis happens when a bursa gets swollen.

Infrapatellar bursitis affects the bursa below the kneecap. This bursa is very close to the insertion point of the patellar tendon. The most common cause of this bursitis is prolonged kneeling. (4)

This bursitis looks like a lump under the kneecap. So, it can look like Osgood-Schlatter disease. Your doctor will perform a physical exam and may ask for some x-rays to tell the difference.

Also, the swelling from Osgood-Schlatter can cause infrapatellar bursitis. But, this bursitis won’t cause Osgood-Schlatter disease. (4)


What causes Osgood-Schlatter in adults?

The main cause is not treating Osgood-Schlatter disease in childhood.

Does Osgood-Schlatter bump go away?

For children and adolescents, probably. Once you treat the disease, the bump should go away. But, this may not be the case for adults with Osgood-Schlatter.

Can Osgood-Schlatter Disease Affect Adults?

Yes, if the disease wasn’t treated during childhood or adolescence.

Conclusion: Bony bump below knee cap in adults

The lump can be a flare-up of Osgood-Schlatter disease. This is a painful condition that can happen in an adult that wasn’t treated properly during childhood.

Most people improve their OSD pain at home. But, severe cases may need surgical treatment.

Whether you have OSD or not, it’s best to go to a health-care professional. They’ll check the lump, tell you what it is, and how to treat it.


  1. Smith J M. “Osgood-Schlatter Disease.” [Updated 2021 Jul 30]. StatPearls. Retrieved on August, 2021 from:
  2. Neuhaus, Cornelia et al. “A systematic review on conservative treatment options for OSGOOD-Schlatter disease.” Physical therapy in sport: official journal of the Association of Chartered Physiotherapists in Sports Medicine vol. 49 (2021): 178-187. doi: 10.1016/j.ptsp.2021.03.002
  3. Santana JA. Jumpers Knee. [Updated 2021 Aug 6]. StatPearls. Retrieved on August, 2021 from:
  4. Jain, Mantu et al. “Infrapatellar bursitis presenting as a lump.” BMJ case reports vol. 14, 5 e243581. 25 May. 2021, doi: 10.1136/bcr-2021-243581
Mitch Torres (PT)
Mitch is a physical therapist, personal trainer, and nutrition coach. Fascinated with the knee joint, Mitch poured that passion into writing about knee pain and how to overcome it with movement. His goal is to teach you how to apply this knowledge into your daily life, so you can keep knee pain away for good.