What causes knee pain when climbing stairs?

Knee Pain When Climbing Stairs: Causes and Clinical Approach

Primary Cause: Patellofemoral Pain Syndrome

The most common cause of knee pain specifically during stair climbing is patellofemoral pain syndrome (PFPS), characterized by retropatellar or peripatellar pain that occurs when load is placed on the knee extensor mechanism during activities requiring knee flexion under load, such as climbing stairs, squatting, or sitting with flexed knees. 1, 2, 3

Key Clinical Features of PFPS

• Pain localizes behind or around the kneecap and worsens with activities that load a flexed knee 1, 2
• Stair climbing (both ascent and descent) is a classic pain-provoking activity 3, 4
• Patients often demonstrate altered muscular recruitment strategies during stair ambulation, including longer vastii activation duration and earlier onset of vastus lateralis 5
• The condition particularly affects adolescents and young adults, though it can persist into middle age 2, 4

Critical Assessment Framework

Anatomic Location Determines Differential

• Anterior knee pain during stairs strongly suggests patellofemoral disorders including cartilage loss, subluxation/dislocation, friction syndrome, patellar tendinopathy, or fat pad impingement 6
• Medial knee pain during stairs points toward medial compartment osteoarthritis or subchondral insufficiency fractures (particularly in middle-aged to elderly females) 6
• Lateral knee pain suggests iliotibial band syndrome or lateral compartment osteoarthritis 6

Exclude Referred Pain First

• Hip pathology commonly refers pain to the knee and must be evaluated if knee imaging is normal 6, 7
• Lumbar spine pathology must be considered when knee radiographs are unremarkable and clinical evidence suggests spinal origin 6, 7
• A thorough clinical examination of the lumbar spine and hip should precede knee-focused imaging 6

Patellofemoral Osteoarthritis: The Continuum

PFPS as Precursor to OA

• Patellofemoral OA shares clinical symptoms with PFPS, including anterior knee pain during stair ambulation and squatting 8
• PF OA is most commonly diagnosed in people aged >40 years, many of whom report a history of PF pain, suggesting PFPS and PF OA form a continuum of disease 8
• People with patellofemoral OA demonstrate altered neuromotor control during stair ambulation, with longer vastii activation and earlier vastus lateralis onset 5

Clinical Evidence in OA

• Physical examination in OA patients routinely reveals knee effusions 9
• Synovitis/effusion severity changes are significantly related to the risk of frequent knee pain 9
• Both bone marrow lesions and synovitis/effusion may indicate the origin of knee pain in osteoarthritis patients 9

Occupational and Activity-Related Considerations

Activities That Increase OA Risk

• Kneeling, squatting, and bending show strong evidence for increased risk of developing knee OA in both men and women 1
• Heavy physical demands demonstrate strong evidence for increased knee OA risk 1
• Lifting activities show strong evidence for increased hip OA risk 1

Activities NOT Associated with Increased Risk

• Climbing stairs or ladders shows strong evidence for NO increased risk of knee OA, which distinguishes stair climbing as a pain-provoking activity in existing pathology rather than a causative factor 1
• Sitting, standing, and walking demonstrate moderate evidence for no increased knee OA risk 1

Diagnostic Algorithm

Initial Evaluation

• Obtain anteroposterior and lateral knee radiographs first to exclude fractures, osteoarthritis, osteophytes, and loose bodies 6, 7
• Assess for knee effusion on physical examination, as presence guides treatment approach 9
• Evaluate hip and lumbar spine clinically before attributing symptoms solely to knee pathology 6, 7

Advanced Imaging Indications

• If radiographs are normal or show only effusion but pain persists, MRI without intravenous contrast is indicated 7
• MRI is excellent for identifying meniscal tears, ligamentous injuries, bone marrow edema, and Baker's cysts 7
• Consider hip radiographs if knee examination and imaging are unrevealing 7

Treatment Approach for PFPS

Exercise Therapy as Primary Treatment

• Exercise therapy for PFPS results in clinically important reduction in pain (mean difference -1.46 on 0-10 scale) and improvement in functional ability, as well as enhancing long-term recovery 2
• Hip plus knee exercises are more effective in reducing pain than knee exercises alone (mean difference -2.20 on 0-10 scale) 2
• Individualized knee-targeted exercise therapy (±hip) should be delivered following assessment of symptom severity and irritability 1

Supporting Interventions

• Prefabricated foot orthoses should be prescribed when patients respond favorably to treatment direction tests 1
• Education should underpin all interventions, providing rationale for treatment and building confidence 1
• Taping may be used as an adjunct to exercise delivery 1

Critical Pitfalls to Avoid

• Do not overlook referred pain from hip or lumbar spine before attributing symptoms exclusively to knee pathology 6, 7
• Avoid premature MRI: approximately 20% of patients with chronic knee pain undergo MRI without recent radiographs 6, 7
• Radiographs may be initially normal in subchondral insufficiency fractures, which later show articular surface fragmentation 6
• Not all meniscal tears are symptomatic, particularly in patients over 45 years 6