What are the possible causes and treatments for knee pops and clicks?

Knee Pops and Clicks: Causes and Management

Initial Clinical Assessment

Knee popping and clicking are common symptoms that require evaluation primarily when accompanied by pain, swelling, locking, or giving way—these associated symptoms indicate potential underlying pathology requiring further workup. 1

Key Diagnostic Distinctions

The approach depends critically on whether the popping occurs in isolation or with concerning features:

• Isolated popping without pain, swelling, or mechanical symptoms is often benign and may represent normal joint sounds from gas bubbles, ligament movement, or tendon snapping 2
• Popping with pain, swelling, locking, catching, or giving way warrants imaging evaluation for meniscal tears, osteochondritis dissecans (OCD), patellofemoral disorders, or cartilage damage 1, 3

Physical Examination Priorities

Document these specific findings systematically:

• Weight-bearing status: Have the patient take at least 4 steps, as this directly influences management decisions 3
• Range of motion: Specifically assess whether the knee flexes to 90 degrees 3
• Joint effusion: Palpate for fluid, which may indicate inflammatory processes or structural damage 1, 3
• Crepitus and tenderness: Assess for grinding sensations and joint line tenderness (83% sensitive and specific for meniscal tears) 2
• McMurray test: Perform concurrent knee rotation with extension (61% sensitive, 84% specific for meniscal tears) 2

Imaging Strategy

When to Order Radiographs

Obtain plain radiographs (AP, lateral, Merchant/sunrise, and tunnel views) if: 1, 3, 4

• Pain has been present for more than 6 weeks
• Popping occurs with pain, swelling, locking, or giving way
• Physical examination reveals effusion or suspected fracture
• Patient is over 45 years with activity-related pain (95% sensitive for osteoarthritis) 2

When to Order MRI

Reserve MRI for specific situations: 1, 3

• Initial radiographs are normal but symptoms persist despite 6 weeks of conservative treatment
• Surgery is being considered
• Need to characterize an OCD lesion found on radiographs
• Evaluating meniscal tears, articular cartilage damage, or bone marrow lesions when radiographs are non-diagnostic

Management Algorithm

First-Line Conservative Treatment

All patients without urgent indications should receive a combination approach of acetaminophen, exercise therapy, and patient education. 3

Pharmacologic Management

• Acetaminophen up to 4g/day is the first-line oral analgesic due to its safer long-term profile compared to NSAIDs 5, 3, 4
• Topical NSAIDs or capsaicin as second-line options if acetaminophen is ineffective, offering excellent safety profiles 5, 3
• Oral NSAIDs for patients unresponsive to acetaminophen, with gastroprotection if gastrointestinal risk factors exist 5, 3
• Intra-articular corticosteroid injection specifically for pain flares accompanied by effusion 5, 3

Exercise Therapy (Essential Component)

• Regular, progressive strengthening exercises with load progression individualized to patient tolerance 3
• Hip strengthening if the patient demonstrates poor tolerance to loaded knee flexion 3
• Eccentric strengthening as pain allows, progressing based on tissue tolerance 3
• Balance, agility, and coordination exercises to improve performance-based function 3

Additional Interventions

• Weight reduction if obese, addressing a key risk factor for knee osteoarthritis 5, 3
• Patient education explaining the condition and pain management strategies 3
• Manual therapy in addition to exercise when symptoms are severe 3
• Prefabricated foot orthoses when the patient responds favorably to treatment direction tests 3

Specific Conditions Causing Popping

Degenerative Meniscal Tears

Arthroscopic surgery is NOT recommended for degenerative knee disease with meniscal tears, even in the presence of mechanical symptoms like clicking or locking. 5

• Exercise therapy is first-line treatment for degenerative meniscal tears 5, 2
• Surgery shows no improvement in long-term pain or function compared to conservative management 5
• Mechanical symptoms (clicking, locking) may be multifactorial and less responsive to arthroscopic meniscectomy 6

Traumatic Meniscal Tears

• Severe traumatic tears (e.g., bucket-handle tears with displaced tissue) likely require surgery 2
• Conservative management with exercise therapy for 4-6 weeks is appropriate for most other traumatic tears 2

Snapping Popliteus Tendon

• Causes lateral knee popping, easily palpated midway between lateral epicondyle and lateral joint line 7, 8
• More prominent when knee is loaded with varus stress during passive flexion-extension 8
• Most cases resolve spontaneously or with conservative treatment 8
• Surgery (tendon release or tenodesis) reserved for persistent symptomatic cases 8

Reassessment and Surgical Referral

Reassessment Timeline

• Reassess at 6 weeks if no favorable outcomes are observed 3
• Consider MRI if not yet obtained and symptoms persist 3

Indications for Surgical Referral

Refer for surgery when: 3, 4

• Radiographic evidence of osteoarthritis with refractory pain and disability despite conservative treatment
• Specific mechanical pathology identified (e.g., unstable OCD lesion, severe bucket-handle meniscal tear)
• Persistent symptoms despite 6+ weeks of adequate conservative treatment with concerning MRI findings
• End-stage osteoarthritis (minimal joint space with inability to cope with pain) after exhausting conservative options 2

Critical Pitfalls to Avoid

• Do not rush to arthroscopy for clicking or locking symptoms in patients over 35 years, as these are often degenerative and surgery provides no benefit 5
• Do not use glucosamine, chondroitin, or acupuncture, as evidence shows no clinically important outcomes 5
• Do not use hyaluronic acid injections, as they are not recommended 5
• Do not assume mechanical symptoms require surgery—they may be multifactorial and respond to conservative treatment 6
• Do not skip weight-bearing assessment, as it directly influences management decisions 3