Pain on the inside of your knee, known as medial knee pain, most often comes from strain or irritation to one of several soft tissues that stabilize the joint. The inner knee is a busy intersection of ligaments, tendons, cartilage, and a fluid-filled cushion called a bursa, and any of these structures can become a source of pain depending on your activity level, age, and injury history. Understanding which structure is involved helps explain what you’re feeling and what to do about it.
What’s on the Inside of Your Knee
The inner (medial) side of your knee relies on a group of structures working together like a functional unit. The main stabilizer is the medial collateral ligament, or MCL, a band of tissue that runs about 10 to 12 centimeters from your thighbone down to your shinbone. It prevents the knee from bending inward. Deeper inside the joint, a second layer of ligament attaches directly to the medial meniscus, a C-shaped piece of cartilage that acts as a shock absorber between the two bones.
Below the joint line, three tendons from your thigh muscles merge together and attach to the inner shinbone. This spot, called the pes anserine, sits about 5 to 7 centimeters below the knee joint. A small fluid-filled sac (bursa) cushions these tendons where they meet the bone. Each of these structures can become irritated or injured independently, which is why inner knee pain can feel slightly different depending on the cause.
MCL Sprains and Tears
The MCL is the most commonly injured ligament in the knee. It typically gets hurt when a force pushes the knee inward, like a hit to the outside of the leg during sports or an awkward landing. MCL injuries are graded by severity. A grade 1 sprain means some fibers are stretched but the ligament is still intact. Grade 2 involves a partial tear, and grade 3 is a complete rupture. Interestingly, incomplete tears (grades 1 and 2) are often more painful than complete ruptures, because the remaining intact fibers are still under tension and sending pain signals.
With a grade 1 injury, you’ll feel tenderness directly along the inner knee and some mild swelling, but the joint stays stable. A grade 2 tear adds more swelling and makes it painful to bend or straighten the knee fully. With a grade 3 tear, the knee may feel unstable or wobbly when you try to stand or change direction, because the ligament can no longer keep the joint from gapping open on the inside.
Recovery times vary predictably by grade. A mild sprain typically heals in one to three weeks. A moderate tear takes four to six weeks. A severe tear needs six weeks or more, and some complete tears combined with other ligament damage may require surgery.
Meniscus Tears
The medial meniscus sits between your thighbone and shinbone and absorbs shock with every step. It tears more easily than the outer meniscus because it’s firmly anchored to the deep ligament layer and the joint capsule, which limits its ability to move out of the way under stress. Tears happen from twisting motions, deep squats, or simply from wear over time.
The hallmark symptoms are catching or locking of the knee, where the joint briefly gets stuck mid-motion. You might also notice a clicking sensation, swelling that builds gradually over a day or two, and sharp pain right along the joint line when you press on the inner knee. The pain tends to worsen with squatting, kneeling, or twisting movements. Unlike an MCL sprain, a meniscus tear often causes mechanical symptoms, meaning the knee itself feels like something is physically in the way.
Pes Anserine Bursitis
This is one of the most common causes of inner knee pain in people who aren’t athletes and didn’t have a specific injury. The bursa beneath the pes anserine tendons becomes inflamed from repetitive friction, and the pain is located noticeably lower than the joint line, about 5 to 7 centimeters below the inner edge of the knee. It’s a distinct enough location that it’s sometimes confused with a problem inside the joint when it’s actually outside it.
Certain activities reliably trigger or worsen the pain: climbing stairs, getting up from a chair, and sitting with crossed legs. Runners are prone to it, as are people who play sports with lateral movements and sudden direction changes like basketball, soccer, and racket sports. It also frequently develops alongside osteoarthritis, so if you’re over 50 with inner knee pain that gets worse going up stairs, this combination is worth considering.
Osteoarthritis of the Inner Knee
The medial compartment of the knee bears more load than the outer side, which is why arthritis tends to develop here first. Medial compartment osteoarthritis is one of the most common orthopedic presentations, especially in people over 50. The cartilage on the inner half of the joint wears down while the outer half and the kneecap area remain relatively spared.
The pain is usually a deep ache that worsens with activity and improves with rest, at least in early stages. Over time, stiffness after sitting and pain with the first few steps of walking become more prominent. As the cartilage thins, the knee may gradually bow inward (a varus alignment), which accelerates the wear by concentrating even more force on the damaged side. Morning stiffness lasting less than 30 minutes, crepitus (grinding or crunching), and gradual onset over months or years are typical patterns that distinguish arthritis from acute injuries.
Your Hip Might Be the Problem
This is the cause people rarely suspect. Hip joint problems, including arthritis and labral tears, can produce pain that radiates to the inner knee without any knee damage at all. In one study, about 34% of patients with hip disease experienced anterior knee pain during movement, and a meaningful subset felt it specifically on the inner side.
The reason is neurological. The femoral and obturator nerves, which originate from the same spinal nerve roots (lumbar vertebrae 2 through 4), supply sensation to both the hip joint capsule and the inner knee. Some nerve fibers literally branch to both locations, so the brain has difficulty telling where the signal is coming from. Anatomical dissections have confirmed that branches of these nerves supply the hip joint lining and then continue down to the inner knee area.
If your inner knee pain doesn’t match any of the patterns above, if your knee exam and imaging come back normal, or if you also have groin stiffness or reduced hip rotation, the source may be your hip rather than your knee.
Strengthening the Right Muscles
Regardless of the specific cause, strengthening the muscles around the knee is a core part of recovery and prevention. The American Academy of Orthopaedic Surgeons recommends targeting five muscle groups for knee stability: the quadriceps (front of the thigh), hamstrings (back of the thigh), adductors (inner thigh), abductors (outer thigh), and gluteal muscles (buttocks).
For medial knee pain specifically, the inner quadriceps and adductors deserve extra attention. The inner quadriceps muscle helps track the kneecap properly and stabilizes the joint during the last degrees of straightening. Hip adduction exercises, where you squeeze your legs together against resistance, strengthen the inner thigh muscles that share tendons at the pes anserine. Stronger glutes also help by controlling how much the knee collapses inward during walking, running, and stair climbing, which reduces strain on all the medial structures.
A practical starting point is straight-leg raises, wall sits, and side-lying leg lifts, progressing to resistance-band exercises and single-leg balance work as strength improves. Consistency over four to six weeks matters more than intensity in the early stages.
Signs That Need Prompt Attention
Most inner knee pain improves with rest, ice, and gradual strengthening. But certain patterns warrant an X-ray or urgent evaluation. The Ottawa Knee Rules, used in emergency departments worldwide, flag the following: you’re 55 or older with a new knee injury, you can’t bend the knee to 90 degrees, you can’t put weight on the leg for four steps (even with a limp), or you have tenderness over the bony bump on the outer upper shinbone (the fibula head). Inability to bear weight immediately after an injury suggests a possible fracture or severe ligament damage. Rapid swelling within hours of an injury, a knee that feels like it might buckle or give way, or locking that won’t resolve also point to injuries that benefit from earlier evaluation rather than waiting.