Knee Pain Decoded: Inner Side, Outer Side, and Stairs

Knee pain is one of the most common complaints out there, and it is far from being a problem only for athletes or older people. Sometimes it pinches on the inside when you get out of the car. Sometimes the knee speaks up when you climb stairs, especially on the way down. Sometimes the pain sits at the back in the hollow of the knee, sometimes on the outside, sometimes as a dull pulling sensation around the kneecap.

The good news: in most cases, knee pain is not a dramatic structural problem, but a mix of overuse, muscle imbalance, and a body that could have used a little more attention. Which structure is actually annoyed can often be guessed from the location: inner side, outer side, kneecap, back of the knee. In this article we walk through the four pain zones step by step, explain what is typically behind each, and show a small self-test plus five gentle exercises for everyday life.

Our panda thinks knees are generally underrated. They carry your full body weight every day, cushion every step, and ask for surprisingly little in return. When they do speak up, it pays to listen.

Where exactly does the knee hurt? Anatomy in brief

The knee is one of the largest and most complex joints in the body. It connects the thigh bone (femur), the shin bone (tibia), and the kneecap (patella), and is stabilised by:

• Four ligaments: the medial collateral ligament, the lateral collateral ligament, and the anterior and posterior cruciate ligaments.
• Two menisci: the medial and lateral meniscus, crescent-shaped cartilage discs that act as shock absorbers.
• Several tendons: the quadriceps tendon at the top, the patellar tendon at the bottom, the pes anserinus tendons on the inside, the iliotibial band on the outside.
• Muscular stabilisers: quadriceps in front, hamstrings behind, adductors on the inside, abductors and gluteus on the outside.

This short overview already makes one thing clear: knee pain can come from very different structures. The location is therefore the most important first hint. Anyone who roughly divides the knee into inside, outside, front (kneecap), and back (hollow of the knee) already has a starting orientation for what is likely and what is not.

Knee pain on the inner side: what is behind it?

Pain on the inside of the knee is among the most common complaints overall, especially in people between 30 and 60. That is also why so many people search for it. Three structures are particularly often involved:

1. Medial meniscus issues

The medial meniscus is more vulnerable than the lateral one because it is firmly attached to the medial collateral ligament and cannot move as freely. Typical triggers are rotational movements under load (classic ones: skiing, football, tennis, but also standing up from a deep squat). The pain sits on the inner joint line, often with a sharp feeling during rotational movements or when kneeling. With a structural tear, blockages can occur, that feeling that the knee is briefly "stuck".

2. Pes anserinus (the goose foot)

A bit further down on the inside, roughly a hand's width below the joint line, three tendons attach to the shin bone: sartorius, gracilis, and semitendinosus. This tendon plate is called the pes anserinus, "goose foot", because the arrangement looks like one. It reacts sensitively to overuse, especially in runners, on long walks in uncomfortable shoes, or after long car or plane trips. The typical pain is a dull, pressure-sensitive spot that gets worse with load.

3. Medial collateral ligament

The medial collateral ligament stabilises the knee against sideways opening. It can be irritated or sprained by direct blows from the outside (football tackles, falls). Typical signs are pressure pain along the ligament, increasing with sideways load. Acute ligament injuries with swelling or a feeling of instability belong in medical hands.

If your knee hurts on the inside and you have not had an acute injury, the cause is often a combination of weak hip abductors (a tendency toward knock-knees), tight adductor pull, and everyday overuse. Many of the exercises further down target exactly this.

Knee pain on the outer side: ITBS and friends

Pain on the outside of the knee is less common than on the inside, but very typical for runners and cyclists. Three suspects sit at the top of the list:

1. Iliotibial band syndrome (ITBS, "runner's knee")

The iliotibial band, also known as the tractus iliotibialis, is a wide band of connective tissue that runs from the pelvis along the outside of the thigh down to just below the knee. With repeated bending and straightening (running, cycling, hiking), it can rub at the outer edge of the knee and become inflamed. The pain is sharp, often pinpointed at the outer upper edge of the shin, and typically appears after a certain distance or time. Studies show that a weak hip abductor (gluteus medius) is a major risk factor.

2. Lateral meniscus issues

Less common than on the medial side, but possible. Triggers are similar: rotational movements under load. Pain on the outer joint line, often during deep squatting or rotational movements.

3. Lateral collateral ligament

Injured less often than the medial collateral ligament. Pain on the outside, especially with blows from the inside or with sideways instability.

With outer-side pain, it is especially worth looking at the hip and glutes. The actual levers are often there: a weak hip abductor, a tight iliotibial band, an unfavourable running technique. More on this in our article on runner's knee.

Knee pain when climbing stairs

"Knee pain on stairs" is one of the most common search queries around the knee. Especially going down is telling: on the way down, the quadriceps has to work strongly eccentrically (braking), and the kneecap is pressed against its sliding groove with high pressure. If this pressure is unbalanced, the knee speaks up. Two diagnoses lead the list:

1. Patellofemoral pain syndrome (PFPS)

Also known as "runner's knee" or simply "knee at the front". The pain sits around or behind the kneecap, especially when going down stairs, walking downhill, sitting for a long time with a bent knee ("moviegoer's knee"), and standing up from a squat. The causes are usually unfavourable tracking of the kneecap in its sliding groove, often through:

• Weak or unbalanced quadriceps (especially the inner part, vastus medialis).
• Weak hip abductors (the knee tilts inwards, knock-knee tendency when climbing stairs).
• Shortened hip flexors or shortened hamstrings.
• Suddenly increased training volume.

Studies like the review by Crossley et al. (Br J Sports Med 2016) show clearly: hip and quadriceps strengthening is the most effective conservative approach for PFPS. Surgery is unnecessary in the vast majority of cases.

2. Patellar tendinopathy (jumper's knee)

Here the pain is precisely localised: at the lower pole of the kneecap, where the patellar tendon attaches. Classic triggers are jumping and stop-and-go sports (volleyball, basketball), but also repetitive loading like stair climbing or high training volumes. The patellar tendon reacts with irritation and structural tendon changes (tendinopathy). Here too, strength training (especially eccentric) is the most evidence-based therapy approach.

3. Early osteoarthritis

In older people or after past injuries, early osteoarthritis can also be behind stair pain. Typical signs: start-up pain that gets better after a few steps, and morning stiffness that resolves within a few minutes. Persistent complaints should be checked by a doctor.

Knee pain in the hollow of the knee

Pain right at the back in the hollow of the knee is less common and is often described as pulling or tense. Common causes:

1. Hamstring tendinopathy

The flexor muscles at the back of the thigh (hamstrings) attach with their tendons just above the back of the knee. With overload (lots of sitting plus sudden activity, sprint sports), these tendon attachments can become pressure-sensitive. Typical: pain when bending against resistance, when standing for a long time, or on the first step after sitting for a while.

2. Baker's cyst

A Baker's cyst is a bulge of the joint capsule that pushes into the back of the knee. It often develops as a consequence of other knee problems (meniscus tear, osteoarthritis), when the joint produces more fluid in response to irritation. Typical sign: a palpable swelling at the back of the knee, a feeling of tightness when bending. A small, asymptomatic Baker's cyst can be observed, a larger or painful one belongs in medical hands.

3. Deep vein thrombosis (red flag)

Rare, but important: a dull, pulling pain in the calf or back of the knee, combined with a one-sided swollen, warm calf, can be a sign of deep vein thrombosis. Risk factors include long immobility (long-haul flight, surgery, bed rest). With this suspicion, see a doctor immediately, this is not a self-test topic.

Self-test: where is the pain and what does it mean?

This compact table helps you sort out your pain. It is of course no substitute for a diagnosis, but it helps you ask the right questions of yourself (or your doctor).

If you cannot place the pain or the complaints last longer than two weeks despite resting, the path to the doctor or physio is worth it.

5 exercises for knee pain

These exercises are gentle, suited to everyday life, and cover the most common muscular levers: quadriceps activation, hip stability, gentle mobility, and targeted self-massage. Please do not work into acute pain, and not with acute swelling. If you are unsure, talk to a physio or doctor first.

1. Seated quadriceps activation. Sit upright, leg fully extended, heel on the floor. Actively press the back of the knee toward the floor, the quadriceps engages, the kneecap pulls slightly upward. Hold for 10 seconds, repeat 10 times, 2 sets per side. Particularly useful for PFPS and pes anserinus complaints.
2. Side-lying hip abduction. Lie on your side, top leg extended, toes pointing slightly downward. Slowly raise the leg toward the ceiling (no higher than 30 degrees), hold briefly, lower under control. 12 reps per side, 2 sets. Strengthens the gluteus medius, which is often weak in ITBS and PFPS.
3. Gentle knee mobility while seated. Seated, extend the painful leg, then gently flex and extend it. Stay within the pain-free range of motion. 15 slow reps, twice a day. Helps reduce fear of movement and lubricates the joint.
4. Self-massage of the outer thigh with the Foam Roller 30. Lie on your side with the foam roller under the outer thigh. Roll gently in small passes with tolerable pressure. Pause briefly on sensitive spots, keep breathing. 60 to 90 seconds per side. Important: not directly on the knee and not into pinching pain. Studies on self-massage of the iliotibial band show that tension feelings often feel more pleasant afterwards.
5. Targeted trigger work with the Duoball 8 or Massage Ball 8. Sit on a chair, place the Duoball 8 or Massage Ball 8 on the pes anserinus (inside, a hand's width below the joint line) or directly on the quadriceps attachment. Build up gentle pressure, breathe, 30 to 60 seconds. Works precisely on pressure-sensitive points without rolling through the whole region.

Three to five times per week, for a few weeks in a row. If something hurts or feels noticeably worse the next day, dial it back a notch or skip it.

When to see a doctor: red flags for the knee

For most knee pain, patience, movement, and gentle self-help are enough. There are situations, however, in which medical clarification is important:

• Acute trauma with immediate strong pain, clear swelling, or an audible pop (suspected ligament rupture, meniscus tear, bone injury).
• Joint blockage, the knee will not fully bend or straighten (suspected trapped meniscus or loose body in the joint).
• Significant swelling or warmth, especially with fever or general illness (suspected infection or acute inflammation).
• Feeling of instability, the knee gives way under load (suspected ligament injury).
• Persistent complaints over more than two to three weeks despite resting.
• Pain in the back of the knee plus a one-sided swollen, warm calf (suspected thrombosis, emergency).

Better to check too early once than too late, especially after a fall or twisting trauma.

Common misconceptions

"Knee pain means osteoarthritis"

Wrong. Osteoarthritis is only one of many possible causes, and it tends to affect older people or those with previous issues. In younger people, muscular imbalances, tendon irritations, and overuse syndromes are the more common suspects.

"With knee pain: rest, rest, rest"

Also wrong. Complete rest weakens the stabilising muscles further, the knee becomes more sensitive, and you spiral down. Gentle, dosed movement within the pain-free range is usually the better path. High-intensity sport during acute pain, of course not.

"You can't rebuild cartilage, so why bother"

Cartilage itself does indeed only regenerate to a very limited extent, that is true. But the surrounding support system (muscles, tendons, ligaments) can absolutely adapt, and that makes the biggest difference in everyday feel. A strong hip and a well-coordinated quadriceps measurably take load off the knee.

"If it hurts once, it hurts forever"

Wrong. A great many acute or subacute knee problems fully resolve with the right mix of movement, load adjustment, and patience. Even patellofemoral syndromes and ITBS can in the vast majority of cases be managed conservatively.

That's it from us

Knee pain is common, varied, and in most cases can be influenced well. The most important information is in the location: inside, outside, front, back of the knee. Anyone who knows where exactly it hurts is already much closer to the cause and can target it specifically, with movement, gentle mobility, and targeted strengthening of the hip and quadriceps.

Our panda would tell you at this point: listen to your knee, take it seriously, but don't catastrophise. Most complaints are not a structural catastrophe, but an invitation to give the leg a little more attention. After a first twisting trauma or with instability: off to the doctor. With a dull pulling sensation after long sitting: take a moment to fit a few exercises in.

If you are working on bringing the knee environment into your routine, a small set can make sense. With a Foam Roller 30 you reach the thighs and calves, with a Duoball 8 you reach the pes anserinus and the quadriceps attachments, and with a Massage Ball 8 the small, pressure-sensitive spots. If you need several of these tools at once, take a look at our 5-Piece Complete Set, it covers everything you need for the exercises above.

Be patient with your knee, your PandaFit team.

Sources

1. Crossley KM, van Middelkoop M, Callaghan MJ et al. 2016 Patellofemoral pain consensus statement from the 4th International Patellofemoral Pain Research Retreat, Manchester. Part 2: recommended physical interventions. Br J Sports Med 2016; 50(14):844-852.
2. Aderem J, Louw QA. Biomechanical risk factors associated with iliotibial band syndrome in runners: a systematic review. BMC Musculoskelet Disord 2015; 16:356.
3. Helito CP, Bonadio MB, Soares TQ et al. The meniscal insertion of the knee anterolateral ligament. Surg Radiol Anat 2016; 38(2):223-228.
4. Bannuru RR, Osani MC, Vaysbrot EE et al. OARSI guidelines for the non-surgical management of knee, hip, and polyarticular osteoarthritis. Osteoarthritis Cartilage 2019; 27(11):1578-1589.
5. Hunter DJ, Bierma-Zeinstra S. Osteoarthritis. Lancet 2019; 393(10182):1745-1759.
6. Malliaras P, Cook J, Purdam C, Rio E. Patellar Tendinopathy: Clinical Diagnosis, Load Management, and Advice for Challenging Case Presentations. J Orthop Sports Phys Ther 2015; 45(11):887-898.
7. AWMF S2k-Leitlinie 033/004. Gonarthrose. Stand 2018, awmf.org. Letzter Zugriff April 2026.
8. Powers CM. The influence of abnormal hip mechanics on knee injury: a biomechanical perspective. J Orthop Sports Phys Ther 2010; 40(2):42-51.

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