Quick Summary
Descending stairs forces the patellofemoral joint to absorb roughly 3.5 times your body weight through eccentric quadriceps loading, which is why anterior knee pain often shows up here first. The three most common causes are patellofemoral pain syndrome, chondromalacia patella, and a posterior-horn meniscal tear. Most cases improve with quadriceps and hip strengthening; persistent or mechanical symptoms should be evaluated by an orthopedic specialist.
If your knee hurts every time you step down a staircase, you are noticing a real biomechanical signal — not weakness, not "getting old." Going downstairs loads the patellofemoral joint with roughly 3.5 times your body weight, far more than walking on level ground, which is why subtle problems with kneecap tracking, cartilage, or meniscus tend to surface here first. This is one of the most common reasons patients book an evaluation with me at Hospital for Special Surgery in New York, and the good news is that most causes respond well to targeted treatment.
Why does going downstairs hurt the knee specifically?
Descending stairs requires eccentric quadriceps contraction — the muscle generates force while lengthening — which drives the patella hard into the trochlear groove of the femur. Walking on flat ground generates roughly 0.5x body weight across the patellofemoral joint. Climbing stairs generates about 2.5x. Going down generates 3.5x or more. That is the biomechanical reason the front of the knee tends to complain here before anywhere else.
Because the joint reaction force is so high, descending stairs is the screening test I use in clinic. If a patient can do everything else but not stairs, the source is almost always anterior (patellofemoral) rather than the inside or outside of the joint. Quadriceps weakness, hip abductor weakness, a high Q-angle, or a tight iliotibial band can all change how the kneecap sits in the trochlear groove and amplify that load.
What are the most common causes?
The three most common diagnoses for "pain only going downstairs" are patellofemoral pain syndrome (PFPS), chondromalacia patella, and a posterior-horn meniscal tear. They are not the same condition, the imaging findings differ, and the treatment paths diverge — which is why the comparison below matters.
| Condition | Where it hurts | Hallmark sign | First-line treatment |
|---|---|---|---|
| Patellofemoral pain syndrome (PFPS) | Around or behind the kneecap | Pain with stairs, squats, prolonged sitting ("theatre sign") | Quadriceps + hip strengthening, activity modification |
| Chondromalacia patella | Behind the kneecap, deep ache | Crepitus / grinding, MRI shows softened cartilage | PT, NSAIDs; cartilage repair if focal lesion |
| Meniscal tear (posterior horn) | Joint line, back or side of knee | Catching, locking, joint-line tenderness | PT first; arthroscopic repair if mechanical |
1. Patellar pain or patellar arthritis (PFPS)
Patellar pain, also called patellofemoral pain syndrome, runner's knee, or anterior knee pain, is the single most common cause of pain going downstairs. The kneecap fails to track smoothly in the trochlear groove of the femur, often because of malalignment, a high Q-angle, weak vastus medialis obliquus (VMO), tight lateral retinaculum, or early patellofemoral arthritis. Pain sits around or behind the kneecap and is worse with knee flexion under load — squats, lunges, and stairs. Some patients also notice swelling, instability, or the knee "giving way."
2. Knee chondromalacia (chondromalacia patella)
Chondromalacia is the softening, fissuring, or breakdown of the articular cartilage on the underside of the patella. It is a structural diagnosis — visible on MRI or arthroscopy — and it produces a deeper, more achy pain than PFPS, with crepitus (grinding) on stairs and stiffness after sitting with the knee bent (the "theatre sign"). Long-standing PFPS often progresses into chondromalacia, which is why we treat the biomechanics aggressively before cartilage damage becomes irreversible.
3. Meniscal tear
A torn meniscus, particularly in the posterior horn, can present primarily as pain going downstairs because deep knee flexion at the top of each step compresses the back of the meniscus. The pain typically sits along the joint line — back or inside of the knee, not behind the kneecap — and is often accompanied by joint-line tenderness, catching, or locking. Mechanical symptoms (a feeling that the knee "catches" mid-motion) are the strongest pointer toward a tear rather than PFPS.
Key takeaways
- Pain only going downstairs almost always points to the front of the knee (patellofemoral joint).
- PFPS and chondromalacia overlap clinically; the distinction is structural cartilage damage on imaging.
- Catching, locking, or joint-line pain shifts suspicion toward a meniscal tear.
When should you see an orthopedic specialist?
See a specialist if knee pain on stairs lasts more than 4-6 weeks, comes with swelling, instability, locking, or a history of injury, or if it is interfering with sleep or work. Early evaluation matters: PFPS that is treated with the right strengthening program in the first 6-8 weeks rarely progresses, while ignored cases can develop cartilage damage that is much harder to reverse.
In my New York practice, the patients who do best are the ones who come in early — runners, dancers, parents going up and down apartment stairs, or anyone who has noticed a clear loss of function. An MRI is rarely needed at the first visit; a focused clinical exam plus a careful history is usually enough to point us at the right diagnosis. If imaging is needed, we order it on the same visit.
What can you do at home before your appointment?
Most patellofemoral pain improves with relative rest, activity modification, and a structured quadriceps and hip strengthening program — not with complete rest. Going completely off your feet causes muscle atrophy that worsens the loading problem. The goal is to lower load while you rebuild the muscles that protect the joint.
- Modify, do not quit. Step down one stair at a time, lead with the non-painful leg, and use the railing while symptoms calm down.
- Ice after activity for 15-20 minutes to reduce swelling and pain.
- Strengthen the right muscles. Targeted physical therapy for the quadriceps (especially VMO), hip abductors, and gluteus medius improves patellar tracking and offloads the patellofemoral joint.
- Avoid pain-provoking depths. Limit deep squats and lunges past 60 degrees of flexion temporarily.
- Try a brief NSAID course if your medical history allows it, and discuss patellar bracing or taping with your physical therapist.
For related reading on the same anatomy and treatment options, see why your knee can hurt going up stairs, knee pain when squatting, knee chondromalacia symptoms and treatment, and exercise, pain, and creaky knees.
Worried it means surgery? Most cases do not.
Many patients arrive convinced they need surgery because the pain is so reproducible. The reality: the majority of patellofemoral pain — even with mild chondromalacia — is managed without an operation. Surgical options like tibial tubercle osteotomy, cartilage repair (MACI), or partial knee replacement are reserved for specific structural problems that do not respond to a focused 3-6 month program. The exam tells us which group you fall into.
Frequently asked questions
Why does my knee hurt only going down stairs and not on flat ground?
Going down stairs puts about 3.5 times your body weight across the kneecap joint, while walking on level ground generates only about 0.5 times your body weight. That much higher load is why early cartilage wear, off-center kneecap tracking, or quad weakness shows up first when going downstairs, even when flat walking still feels normal.
Is it patellofemoral pain syndrome or chondromalacia patella?
Patellofemoral pain syndrome (PFPS, a clinical diagnosis based on symptoms) is named for kneecap pain with no visible cartilage damage. Chondromalacia patella is a structural finding seen on MRI or arthroscopy — softened or fissured cartilage behind the kneecap. You can have PFPS without chondromalacia, but long-standing PFPS is often what eventually develops into chondromalacia.
Should I stop using the stairs if my knee hurts going down?
You don't need to avoid stairs entirely. Modify temporarily by stepping down with the non-painful leg first, holding the handrail, and limiting repeated descents while you rebuild quad and hip strength. Completely avoiding stairs leads to muscle weakening that makes the problem worse. If the pain lasts more than 4 to 6 weeks despite modification, see an orthopedic specialist.
Can a meniscal tear cause pain only when going down stairs?
Yes — a meniscus tear can show up primarily as pain with descending stairs, especially when the tear sits in the back portion of the meniscus. The deep knee bending required at the top of the descent loads the back of the meniscus. Pain along the joint line, the knee catching, or the knee locking alongside stair pain are key signs that point toward a meniscus tear rather than kneecap pain.
When should I see an orthopedic surgeon for knee pain on stairs?
See an orthopedic specialist if knee pain on stairs lasts more than 4 to 6 weeks, comes with swelling, instability, locking, or a history of injury, or if it limits work or sleep. An MRI is rarely needed at first, but persistent symptoms or mechanical signs warrant imaging and a clinical exam to rule out cartilage damage, meniscus tears, or off-center kneecap tracking.
If your knee pain is interfering with daily life, do not ignore it. Early assessment and intervention — whether through exercise modification, structured physical therapy, or, in select cases, surgery — can make a meaningful difference in your recovery timeline and the long-term health of your knee. To request an evaluation with Dr. Sabrina Strickland at Hospital for Special Surgery in New York, please book an appointment.
Photo by Frank Eiffert on Unsplash
