What is the best course of action for a 37-year-old female with a swollen right knee, who experienced a popping sensation 2 weeks ago while getting up quickly, has no pain, can bend and bear full weight, and has not tried over-the-counter (OTC) medications, ice, or heat?

Management of Painless Knee Swelling After Popping Sensation

Begin with conservative management including ice therapy (10-minute applications multiple times daily), acetaminophen up to 4g/day, and immediate initiation of progressive exercise therapy, while obtaining plain radiographs only if symptoms persist beyond 6 weeks or if examination reveals concerning features. 1, 2

Immediate Assessment Priorities

The absence of pain with full weight-bearing and normal range of motion are reassuring signs that argue against urgent structural damage requiring immediate imaging. 2 However, document the following key examination findings:

• Confirm full weight-bearing capacity by having her take at least 4 steps 2
• Assess range of motion to verify she can flex the knee to at least 90 degrees 2
• Palpate for joint effusion, as its presence would suggest intra-articular pathology requiring imaging even in the absence of pain 1, 2
• Inspect for deformity, ecchymosis, or erythema to evaluate injury severity 2

The "popping" sensation she experienced likely represents a soft tissue event rather than a fracture, given her preserved function. 1

Initial Conservative Treatment Protocol

Cryotherapy Application

• Apply ice through a wet towel for 10-minute periods, repeated multiple times daily rather than continuous application 1, 3
• This intermittent approach sustains reduced tissue temperature (target reduction of 10-15°C) while allowing superficial skin temperature to normalize between applications 3
• Continue ice therapy for the first 72 hours, then as needed for swelling control 4

Pharmacologic Management

• Start acetaminophen up to 4g/day as first-line oral analgesic, given its safer profile for ongoing use compared to NSAIDs 4, 2
• If acetaminophen provides insufficient relief, consider oral NSAIDs with gastroprotection if gastrointestinal risk factors exist 4, 2
• Topical NSAIDs represent an alternative with fewer systemic side effects 1

Exercise Therapy (Critical Component)

Initiate therapeutic exercise immediately rather than prolonged rest, as early mobilization improves outcomes. 1, 5

• Begin with gentle range of motion exercises to prevent stiffness 4
• Progress to eccentric strengthening exercises as tolerated, which have high-level evidence for reversing soft tissue pathology 1, 2
• Add quadriceps strengthening using exercises like quad sets, short-arc extensions, and straight leg raises performed 5-7 repetitions, 3-5 times daily 4
• Incorporate hip strengthening if she demonstrates poor tolerance to loaded knee flexion 2
• Advance to balance, agility, and coordination exercises to restore full function 2

A randomized trial demonstrated that accelerated exercise protocols during the first week after acute joint injury significantly improved function compared to standard rest-based approaches. 5

Imaging Decision Algorithm

Defer radiographs at this 2-week timepoint given the following favorable features: 2

• No pain with weight-bearing or movement
• Full range of motion preserved
• Ability to bear full weight
• Symptoms present less than 6 weeks

Obtain plain radiographs (AP, lateral, Merchant, and tunnel views) if: 1, 2

• Symptoms persist beyond 6 weeks
• Joint effusion is present on examination
• Pain develops or worsens
• Mechanical symptoms emerge (locking, catching)
• Functional limitations develop

Reserve MRI for specific situations: 2

• Persistent symptoms despite 6+ weeks of adequate conservative treatment
• Normal radiographs but ongoing symptoms
• Consideration of surgical intervention
• Suspected meniscal tear, cartilage lesion, or ligament injury

Patient Education and Activity Modification

• Explain that pain does not necessarily correlate with tissue damage, and her lack of pain is a positive prognostic indicator 1
• Implement relative rest by reducing activities that increase swelling while maintaining activities that don't worsen symptoms 1
• Avoid complete immobilization, which causes muscular atrophy and deconditioning 1
• Use the "pacing principle" of "small amounts often" linked to daily activities to establish routine 2

Critical Pitfalls to Avoid

• Joint effusions are uncommon with simple soft tissue injuries and suggest intra-articular pathology requiring imaging 1
• Complete immobilization must be avoided despite the swelling, as it leads to worse functional outcomes 1
• Do not delay exercise therapy waiting for swelling to completely resolve, as early mobilization improves recovery 5

Reassessment Timeline

Reassess at 6 weeks if no favorable outcomes are observed. 2 At that point, obtain radiographs if not yet done, and consider MRI if symptoms persist with normal radiographs. 2

Advanced Interventions (If Conservative Management Fails)

• Intra-articular corticosteroid injection may be considered specifically for pain flares accompanied by persistent effusion 2
• Extracorporeal shock wave therapy (ESWT) represents a safe option for chronic symptoms persisting beyond 3-6 months 1
• Surgical consultation is warranted if symptoms persist after 6 months of appropriate conservative management 1