Inner (medial) knee pain

Expert reviewer, Mr Damian McClelland, Trauma and Orthopaedic Consultant, and Clinical Director for Musculoskeletal Services at Bupa
Next review due March 2022

Inner knee pain may also be called medial knee pain. Medial simply means middle – so the side of your knee nearer the middle of your body (that is, the left side of your right knee and the right side of your left knee).

You may have pain over, or just below, the inner side of your knee. It may be worse when you bend and straighten your leg. Your knee may feel as if it is about to give way, may lock (get stuck) or catch when you bend your leg.

A diagram by Bupa of where inner knee pain is located

Causes of inner knee pain

There is no single cause, but there are several reasons why you may have inner knee pain. It’s more common in:

  • footballers, skiers, rugby players and those who play sports
  • other activities that involve sudden twisting or pivoting of the knees
  • those who suddenly increase the amount of activity they normally do
  • activities that result in over-use of the knee, such as cycling or swimming breaststroke
  • older people, due to falls or arthritis

Conditions associated with inner knee pain

There are several medical conditions linked to inner knee pain. Generally, they’re caused by damage from a sports injury, from overusing the knee during exercise or from getting older.

Medial collateral ligament injury is caused by stretching or tearing the band of tissue that connects the inside of the thigh bone to the inside of the shin bone. A ligament is a band of tissue that connects one bone to another. The medial collateral ligament runs down the inner side of your knee. It helps to stabilise the knee.

Meniscal injury is commonly known as a torn cartilage. The meniscus cartilages act like shock absorbers and may tear when you twist your knee with your foot still on the ground. This type of injury is common in sports where you have to change direction suddenly, such as football. It can happen in occupations involving lifting and twisting, such as construction or manual labouring. The meniscus can also tear in older people because of wear and tear, without any particular injury.

Anterior cruciate ligament injury occurs when the ligament is stretched or torn. It runs across the knee from the thigh to the shin bone and helps to stabilise the two bones when walking. A tear may be either complete or partial. It’s a sudden injury, caused by twisting or overextending the knee. It can happen if you suddenly slow down, stop or change direction and is nearly always associated with sports.

Osteoarthritis of the knee is a common cause of knee pain. The smooth, shiny cartilage that lines the knee joint becomes worn and rough. This causes pain and increasing damage to the knee. It mostly affects people over 50. The older you are, the more likely you are to get it.

Patellofemoral pain syndrome (PFPS) means pain related to the kneecap (the patella) and the thigh bone (the femur). When you bend and straighten your leg, your kneecap slides up and down a groove at the front and end of your thigh bone. Damage or swelling where the kneecap and thigh bone meet stops the kneecap from sliding smoothly and causes pain. The knee may also feel as if it will give way. PFPS is one of the common causes of pain at the front of the knee but can also cause pain over the inner part of the knee.

Pes anserinus syndrome (or pes anserine bursitis) causes pain on the inside of the knee, over a fluid-filled sac called the anserine bursa.

Medial plica syndrome is when a small fold of tissue (a plica) inside the knee becomes inflamed. It tends to come on when you’ve suddenly become more active and causes acute pain across the inside of the knee.

Bone icon Looking for physiotherapy?

You can access a range of treatments on a pay as you go basis, including physiotherapy. Find out more >

Bone iconLooking for physiotherapy?

Inner knee pain symptoms

Other symptoms you may have with inner knee pain will vary, depending on the cause. You may have swelling, pain with particular movements and your knee may click or get stuck in one position (lock).

With a medial collateral ligament injury, pain and swelling usually come on straightaway after your accident, although you may not always have swelling. The injury causes pain over the inner knee, which may be focussed on the mid-point of the knee joint. The ligament helps to keep the knee stable, so you may feel as if your knee is going to give way.

Symptoms of a torn meniscus cartilage generally come on up to a day after the initial injury. Pain and swelling may get worse and you may have difficulty fully straightening your leg. A more severe tear will be painful from the start.

The knee may also lock, feel stiff or feel unstable, as if it’s about to give way.

Pain from an anterior cruciate ligament injury may be sudden and you may hear a ‘pop’. The knee is likely to swell from internal bleeding and may feel as if it’s going to give way.

Osteoarthritis usually causes pain when you’re putting weight on the leg, and is relieved by rest. You may have stiffness and loss of movement first thing in the morning or after sitting for a while. You may also have some swelling around your knee.

Patellofemoral pain syndrome causes an ache inside your knee. It’s made worse by running, climbing stairs, squatting or after sitting for a long time. Your knee may feel unstable, as if it’s going to give way.

Medial plica syndrome typically causes pain on climbing stairs, running or squatting. You may have pain if you have your leg bent for a long time. The knee may also catch or click when you bend your leg.

Pes anserine pain gets worse when you repeatedly bend your leg, such as when going up and down stairs. Some people have pain at night, from one leg pressing on the other, which can disturb sleep. You may have slight swelling, but there isn’t usually a collection of fluid on the knee. Many people with pes anserine pain also have osteoarthritis.

Diagnosis of inner knee pain

Your doctor will examine your knee and take a history, asking about:

  • the type of pain you have, when it started and whether it comes and goes
  • how active you are
  • any activity, accident or injury that could have caused it

They may suggest an X-ray or a magnetic resonance imaging (MRI) scan, but this is not always necessary. The examination and your history may be enough to diagnose you.

If you have cartilage or ligament damage, your doctor may suggest a procedure to look inside your knee, called an arthroscopy (often referred to as ‘keyhole surgery’). This involves making a small cut in your knee and inserting a thin tube with a camera on the end. As well as diagnosing the problem, the procedure can also be used to repair or remove damaged tissue.

Managing inner knee pain

Immediately after an injury, you can help yourself by resting your leg, using an ice pack and taking painkillers, such as ibuprofen. If you can’t put weight on your leg, you may need crutches. Avoid twisting or bending the knee as far as possible.

If your injury is mild, you may not need to see a doctor or physiotherapist, but you should if:

  • you cannot put weight on the affected leg
  • you have severe pain, even when not bearing weight
  • your knee gives way, clicks, or locks (gets stuck)
  • your knee is deformed or misshapen
  • your knee is hot, red or very swollen or you have a fever
  • you have pain, swelling, numbness, tingling, or a bluish discoloration in your calf
  • you’re still in pain after three days

Treatment of inner knee pain

The treatment that you have for your inner knee pain will depend on what condition is causing the pain.

For information on treatments, please see the relevant knee condition page.

Did our information help you?

We’d love to hear what you think. Our short survey takes just a few minutes to complete and helps us to keep improving our health information.

About our health information

At Bupa we produce a wealth of free health information for you and your family. This is because we believe that trustworthy information is essential in helping you make better decisions about your health and wellbeing.

Our information has been awarded the PIF TICK for trustworthy health information. It also follows the principles of the The Information Standard.

The Patient Information Forum tick

Learn more about our editorial team and principles >

    • Knee pain - assessment. NICE Clinical Knowledge Summaries., last updated July 2017
    • Medial collateral ligament injury. BMJ Best Practice., last updated November 2017
    • Crossley K, Cook J, Cowan S. Biomechanical aspects of injury in specific sports. Brukner & Khan's Clinical Sports Medicine (5th ed.), accessed October 2018
    • Osteoarthritis. PatientPlus., last updated March 2017
    • Meniscal tear. BMJ Best Practice., last updated March 2018
    • Anterior cruciate ligament injury. BMJ Best Practice., last updated March 2018
    • Osteoarthritis. BMJ Best Practice., last updated October 2018
    • Patellofemoral pain syndrome. BMJ Best Practice., last updated March 2018
    • Knee anatomy. Encyclopedia Britannica., accessed October 2018
    • Patellofemoral syndrome. Medscape., last updated January 2017
    • Simon C, Everitt H, Van Dorp F, et al. Musculoskeletal problems. Oxford Handbook of General Practice (4th ed.) Oxford: Oxford University Press 2014,
    • Lee PYF, Nixion A, Chandratreya A, et al. Synovial plica syndrome of the knee: a commonly overlooked cause of anterior knee pain (how is it diagnosed?) Surg J 2017; 3(1):e9–e16
    • Knee bursitis., last updated February 2018
    • Assessment of knee injury. BMJ Best Practice., last updated June 2018
    • Knee ligament injuries. PatientPlus., last updated February 2017
    • Soft tissue knee injury. Medscape., last updated February 2016
    • Knee pain. Medline Plus., last updated October 2018

  • Reviewed by Alice Windsor, Specialist Health Editor, Bupa UK Health Content Team, March 2019
    Expert reviewer, Mr Damian McClelland, Trauma and Orthopaedic Consultant, and Clinical Director for Musculoskeletal Services at Bupa
    Next review due March 2022