Last updated: 2026-10-15
It Hurts Even When You Press Just One Spot Below the Inner Knee
If one spot below the inside of your knee hurts when you press it and you feel a sharp twinge when standing up from a chair, the same spot also hurts the moment your knees touch while you lie on your side. This pain may come not only from a cartilage problem inside the knee joint but also from pes anserine tendinitis, an inflammation of the pes anserine tendons and bursa where they attach to the upper inner part of the shinbone, below the joint line.
For example, a woman in her 60s may come in because of a sharp twinge below the inside of her knee when she stands up from a chair or walks down stairs. Even if she was previously told she had early knee arthritis, the spot that actually hurts shows up clearly at one place a little below the gap where the knee joint surfaces meet.
This upper inner part of the shinbone, below the knee joint line, is where a structure called the pes anserinus ("goose's foot") sits: three tendons coming down from the thigh gather there and attach together. Inner knee pain arising around the pes anserine tendons and bursa, together with tenderness on the inner side just below the joint, is also grouped under the name pes anserine syndrome.(Helfenstein M Jr et al., 2010)
At Ansim Teunteun Pain Clinic, we check this pes anserinus site directly with ultrasound diagnosis, and we use ultrasound-guided injections and extracorporeal shockwave therapy to treat pes anserine tendinitis.
Why Does It Hurt More When Standing Up from a Chair or Using Stairs?
Three tendons coming down from the thigh attach to the upper inner part of the shinbone (tibia), and because they fan out like the webbed toes of a goose, the area was named the pes anserinus ("goose's foot"). The tendons of the sartorius, which crosses obliquely down from the front of the thigh, the gracilis on the inner thigh, and the semitendinosus at the back of the thigh all gather at this spot. According to a study that dissected and analyzed 86 legs of Korean cadavers, the sartorius tendon attaches at a relatively shallow layer, while the gracilis and semitendinosus tendons attach at a deeper layer below it.(Lee JH et al., 2014)
Between these three tendons and the tibia lies the pes anserine bursa, a thin fluid-filled sac that reduces friction. The three muscles that make up the pes anserinus bend the knee and support the inner side of the knee so it does not wobble. So when you repeat movements such as sitting down and standing up from a chair, going up and down stairs, or squatting, these three muscles contract. Each time, the spot where the pes anserine tendons attach to the bone is pulled again and again. On top of that, when you lie on your side and your knees press against each other, the pes anserinus area, which sits between the bone and the skin, is compressed directly and the pain gets worse.
Beyond the physical strain of these movements, your overall health and body type also have an effect. Diabetes is a known predisposing factor for pes anserine syndrome, and being overweight and having knee arthritis are also listed as risk factors that increase the load on the pes anserinus.(Helfenstein M Jr et al., 2010) In fact, when patients with symptomatic knee arthritis were examined, pes anserine bursitis was more common in women than in men and more common in older patients.(Uysal F et al., 2015)
When You've Been Told It's Arthritis, but the Pain Is in One Specific Spot
Knee pain has many causes, including degenerative osteoarthritis, meniscal injury, patellar tendinitis, ligament injury, and synovitis. Among these, degenerative osteoarthritis makes the whole knee ache or feel stiff in the morning, and the joint may swell or build up extra joint fluid. When the medial (inner) meniscus is damaged, pain develops right at the inner side of the knee joint line, and the pain may get worse when you twist the knee, or the joint may feel as if it catches.
Pes anserine tendinitis, by contrast, mainly hurts when you press on the upper inner part of the shinbone, below the knee joint line. However, because the areas where patients feel pain lie close to one another, it is easily confused with other joint conditions. One study reviewed 509 knee imaging exams performed on suspicion of an injury inside the joint and found that pes anserine bursitis accounted for 2.5% of them. The most common symptom in those cases was pain along the inner joint line, similar to a medial meniscus tear.(Rennie WJ et al., 2005)
Pes anserine lesions also occur together with knee arthritis in no small number of cases. In a study that examined 170 knees of patients with symptomatic knee arthritis by ultrasound, pes anserine bursitis was observed in 34 knees, or 20%, and the higher the arthritis grade, the greater the length and area of the pes anserine bursa.(Uysal F et al., 2015) For this reason, if pain in the upper shinbone does not settle and keeps going even while you are being treated for arthritis, it should also be checked whether a pes anserine lesion is present alongside it.
If the whole knee is swollen or feels warm, we first examine whether there is inflammation or damage inside the joint. If the pain is severe enough to make walking difficult, or if the knee feels unstable and gives way, an injury inside the joint and a ligament injury need to be checked first. Even if the discomfort is mild, if knee pain lasts more than 2 weeks, it is advisable to see a doctor and identify the exact cause.
Can Ultrasound Show the Pes Anserinus Area Directly?
First, we press by hand on the knee joint line and then on the inner shinbone below it, one after the other, to find the spot where you feel the most pain. Next, we have you bend and straighten your knee yourself to see how the pain at the pes anserinus site increases with movement.
An X-ray is an exam that checks the shape of the bones and the joint space, while ultrasound is an exam that looks at soft tissues such as tendons and bursae. With ultrasound, we look at whether the pes anserine tendon attachment has thickened and whether fluid has collected inside the bursa.
Ultrasound diagnosis involves no radiation exposure, and it allows a dynamic exam of the tissue around the pes anserinus while you bend, straighten, and move your knee. During this exam, we also look at the condition of the inner knee ligament and whether joint fluid has increased, not just the pes anserinus. Ultrasound diagnosis at Ansim Teunteun Pain Clinic takes about 10 to 15 minutes, and during the exam you watch the ultrasound screen together with the doctor and hear an explanation of the current tissue findings right away.
In a study of patients with knee arthritis, too, ultrasound was used to evaluate pes anserine bursitis objectively.(Uysal F et al., 2015) Furthermore, an accurate imaging diagnosis of pes anserine bursitis has been reported to help reduce unnecessary arthroscopy that might otherwise be performed when the condition is mistaken for a tear inside the joint.(Rennie WJ et al., 2005)
How Do the Injections and Extracorporeal Shockwave Therapy Used for Pes Anserine Tendinitis Differ?
When treatment begins, you should also adjust your daily habits so that the pes anserinus is not pulled or pressed in everyday life. While the pain is settling down, cut back on going up and down stairs, squatting, and walking for long periods so that the tendon attachment can rest. If you put a pillow between your knees when you sleep on your side at night, you can reduce the pressure on the pes anserinus area from your knees touching each other.
At Ansim Teunteun Pain Clinic, we decide whether to use ultrasound-guided injections or extracorporeal shockwave therapy alone or in combination, based on the examination and the ultrasound diagnosis. If the tendon damage has become chronic, with pain that lasts a long time even after ultrasound-guided injections or extracorporeal shockwave therapy, we discuss autologous blood regenerative therapy with you. Autologous blood regenerative therapy is a treatment not covered by national health insurance, in which the medical team separates and concentrates the cells and growth factors involved in regeneration from your own blood and injects them into the damaged area under ultrasound guidance. If the exam also confirms knee arthritis, we plan a separate arthritis treatment that addresses the inside of the joint as well.
Ultrasound-guided injection is a treatment that places medication precisely around the pes anserine bursa and the tendon attachment while the anatomical location is viewed on ultrasound. An ultrasound-guided injection takes about 5 to 10 minutes and is given 1 to 3 times at 1- to 2-week intervals, with the schedule set according to your symptoms and response to treatment. Ultrasound-guided injections can be covered by national health insurance, and depending on the medication used, some items are not covered. A randomized study of 60 patients with pes anserine bursitis compared a single ultrasound-guided steroid injection with 3 weeks of extracorporeal shockwave therapy given once a week. In this study, pes anserine thickness and pain decreased after treatment in both groups, and the decrease in pes anserine thickness was larger in the injection group.(Majidi L et al., 2023)
Extracorporeal shockwave therapy sends shockwave energy from outside the body to trigger a healing response in the stiffened, damaged tendon attachment. Depending on the pattern of the lesion, we use focused shockwaves, which concentrate energy at a target depth, and radial shockwaves, which deliver energy to relatively wide, shallow tissue. At Ansim Teunteun Pain Clinic, one extracorporeal shockwave therapy session takes about 10 minutes. We advise 3 to 5 sessions at 1-week intervals and set the schedule according to your symptoms and response to treatment. Extracorporeal shockwave therapy is not covered by national health insurance. In a randomized study of 40 patients with pes anserine bursitis whose pain had lasted more than 3 months and had not responded to conservative treatment, the shockwave group had lower pain scores than the sham shockwave group when assessed at 3 weeks, right after treatment, and at 8 weeks.(Khosrawi S et al., 2017)
For 1 to 2 days after an injection, cut back on strenuous exercise, and to prevent infection, wait 1 to 2 days before using public baths, saunas, or swimming pools. If redness, warmth, or severe pain at the injection site continues, you should contact the clinic. After extracorporeal shockwave therapy as well, avoid intense exercise for 24 to 48 hours and watch how your knee responds without overusing it.
Jinyeol Kwon · Anesthesiology and Pain Medicine Specialist · Ansim Teunteun Pain Clinic
References
- Helfenstein M Jr, Kuromoto J (2010). Anserine syndrome.. Rev Bras Reumatol. PMID: 21125167
- Lee JH, Kim KJ, Jeong YG (2014). Pes anserinus and anserine bursa: anatomical study.. Anat Cell Biol. PMID: 24987549
- Uysal F, Akbal A, Gökmen F (2015). Prevalence of pes anserine bursitis in symptomatic osteoarthritis patients: an ultrasonographic prospective study.. Clin Rheumatol. PMID: 24797774
- Rennie WJ, Saifuddin A (2005). Pes anserine bursitis: incidence in symptomatic knees and clinical presentation.. Skeletal Radiol. PMID: 15940489
- Majidi L, Saeb F, Alaei B (2023). Comparison of the Effectiveness of Local Corticosteroid Injection and Extracorporeal Shockwave Therapy in Patients With Pes Anserine Bursitis: An Open-Label Randomized Clinical Trial.. Med J Islam Repub Iran. PMID: 37123337
- Khosrawi S, Taheri P, Ketabi M (2017). Investigating the Effect of Extracorporeal Shock Wave Therapy on Reducing Chronic Pain in Patients with Pes Anserine Bursitis: A Randomized, Clinical-Controlled Trial.. Adv Biomed Res. PMID: 28626745
Frequently Asked Questions
Q. Are pes anserine tendinitis and pes anserine bursitis the same thing?
Strictly speaking, they refer to two different things, inflammation of the tendon and inflammation of the bursa beneath the tendon, but because the two structures sit close together, the terms are sometimes used together when describing pain in the pes anserinus area. When you are trying to understand a treatment plan, it helps to check not only the diagnosis name but also whether the actual target of treatment is the area around the tendon or the bursa.
Q. What should I do if pain in the pes anserinus area remains after knee arthritis treatment?
When arthritis and pes anserine tendinitis occur together, tenderness below the inside of the knee may remain even after the joint pain has eased. At Ansim Teunteun Pain Clinic, we examine where the tenderness remains and ask how the pain changes with daily movements to decide whether the pes anserinus area needs additional treatment.
Q. During treatment for pes anserine tendinitis, how much should I cut back on walking and using stairs?
Rather than following a fixed step count, adjust the amount based on the pain you feel during activity and how that pain changes from after the activity through the next day. If pain lingers for a long time after walking or is worse the next day, shorten the distance and time, and keep a record of whether the pain settles down once you use the stairs less.
Q. How are the treatment intervals and insurance coverage for ultrasound-guided injections and extracorporeal shockwave therapy determined?
The interval between repeat ultrasound-guided injections is set according to the medication used, the date of the previous injection, and changes in pain, and the schedule for extracorporeal shockwave therapy is also adjusted according to how well pain and daily activity recover after treatment. For cost, check whether the procedure and the ultrasound exam are each covered by national health insurance or not, and separately confirm the coverage of private medical indemnity insurance under the terms of your policy and the documents it requires.