What causes my knee to click?

What Causes Knee Clicking?

Knee clicking is most commonly a benign phenomenon caused by normal joint mechanics, but when accompanied by pain, it may indicate underlying pathology such as meniscal tears, cartilage lesions, loose bodies, or patellofemoral tracking issues. 1, 2

Benign vs. Pathological Clicking

Benign Clicking (Most Common)

• Asymptomatic clicking or grinding is extremely common and does not require treatment. 1, 3
• Normal joint mechanics can produce audible sounds from gas bubbles, ligament/tendon movement over bony prominences, or synovial tissue displacement. 4
• The popliteal tendon snapping over the lateral femoral condyle can cause lateral knee clicking and popping. 5

Pathological Clicking (Requires Evaluation)

When clicking occurs with pain, swelling, or functional limitation, consider:

• Meniscal tears: Clicking with twisting/pivoting pain, joint line tenderness (83% sensitivity, 83% specificity), or positive McMurray test (61% sensitivity, 84% specificity). 3
• Loose bodies: Intra-articular fragments causing mechanical symptoms and catching. 1
• Cartilage lesions: Focal chondral defects or osteochondral lesions producing grinding/clicking. 1, 6
• Patellofemoral tracking disorders: More common in teenage girls and young women, causing anterior knee clicking with squatting. 3, 4

Critical Clinical Context

Age matters significantly in interpretation:

• Patients >45 years: The majority of people over 70 have asymptomatic meniscal tears, and the likelihood of a tear is similar in painful versus painless knees in ages 45-55. 2, 7
• Younger patients (<40 years): More likely to have acute traumatic tears or patellofemoral disorders. 3, 4

Mechanical symptoms (clicking, locking, catching) are multifactorial and may not respond to surgery. 8, 6 Recent evidence shows that clicking/grinding resolves in 65.6% of patients after arthroscopy, but this is not an indication for surgery in degenerative knee disease. 1, 6

Diagnostic Approach

Initial Evaluation

• Start with plain radiographs (AP, lateral, tunnel, and tangential patellar views) to rule out osteoarthritis, loose bodies, and other bony pathology. 9, 2
• Look specifically for: joint space narrowing, osteophytes, loose ossific bodies, and patellofemoral alignment. 1, 9

Advanced Imaging (If Symptoms Persist)

• MRI without contrast is indicated when radiographs are normal/non-diagnostic and symptoms continue. 1, 9, 2
• MRI detects meniscal tears (96% sensitivity, 97% specificity at 3T), cartilage lesions, bone marrow edema, and loose bodies. 2, 7
• Important caveat: In older patients, focus on bone marrow lesions and synovitis/effusion rather than meniscal tears alone, as these correlate better with pain. 7

Management Algorithm

For Clicking WITHOUT Pain or Functional Limitation

• Reassurance only—no imaging or treatment needed. 1, 3

For Clicking WITH Pain

1. Conservative management first (regardless of imaging findings in degenerative disease):

   • Exercise therapy for 4-6 weeks 3
   • Weight loss if overweight 3
   • Patient education and self-management 9, 3
   • Acetaminophen up to 4g/day as first-line analgesia 9

2. Surgery is NOT indicated for degenerative meniscal tears even with mechanical symptoms. 1, 3

3. Surgery may be considered only for:

   • Severe traumatic bucket-handle tears with displaced tissue 3
   • True locked knee (persistent, not intermittent) 1
   • Loose bodies causing recurrent locking 1

Common Pitfalls to Avoid

• Do not attribute clicking to meniscal tears on MRI in patients >45 years without considering that tears are equally common in asymptomatic knees. 2, 7
• Do not recommend arthroscopy for degenerative knee disease with clicking—evidence shows no benefit over conservative management. 1
• Do not overlook smoking, obesity, and multiple compartment cartilage lesions, which predict persistent symptoms after any intervention. 6
• Do not assume mechanical symptoms require mechanical solutions—clicking/locking may be multifactorial and often resolve with conservative care. 8, 6