What is the best course of treatment for a patient who hyperextended their knee, resulting in proximal knee pain, swelling, and a palpable knot that migrates with activity?

Management of Acute Knee Hyperextension Injury with Migrating Swelling

This patient requires immediate imaging with standard knee radiographs (AP, lateral, Merchant, and tunnel views) to rule out osteochondritis dissecans or other intra-articular pathology, followed by conservative management with relative rest, ice therapy, NSAIDs, and early therapeutic exercise if imaging is reassuring. 1, 2

Initial Diagnostic Approach

The presentation of proximal knee pain with a palpable "knot" that migrates and swelling that worsens with activity after hyperextension injury raises concern for several pathologies:

• Obtain standard radiographs immediately including AP, lateral, Merchant (sunrise), and tunnel views, as patients presenting with knee pain, swelling, and mechanical symptoms warrant imaging to evaluate for osteochondritis dissecans (OCD) lesions or other structural damage 1

• Consider MRI if radiographs show abnormalities or if concomitant pathology is suspected (meniscal tear, ligament injury, or articular cartilage damage), though this is optional based on initial findings 1

• The migrating "knot" suggests possible fluid collection or soft tissue pathology rather than fixed bony abnormality, but imaging remains essential to exclude serious intra-articular damage 1

Conservative Management Protocol

Immediate Phase (Week 1-2)

• Implement relative rest by reducing activities that aggravate symptoms while maintaining activities that don't worsen pain, avoiding complete immobilization which causes muscular atrophy 2, 3

• Apply ice through a wet towel for 10-minute periods multiple times daily for short-term pain relief and swelling reduction 2, 3

• Prescribe NSAIDs (oral or topical) for short-term pain control, recognizing they provide symptomatic relief but don't alter long-term outcomes 2, 3

  • Topical NSAIDs offer similar pain relief with fewer gastrointestinal side effects 2, 3

• Consider contrast therapy (alternating heat and cold) which has demonstrated effectiveness in reducing knee pain, swelling, and improving range of motion even after a single treatment 4

Progressive Rehabilitation Phase (Week 2-6)

• Initiate eccentric strengthening exercises as pain allows, as these have proven beneficial in reversing degenerative changes in tendinosis and may help other soft tissue injuries 2, 3

• Implement knee-targeted exercise therapy with progression based on symptom severity and tissue tolerance to load 1

• Add hip strengthening if indicated, particularly if the patient demonstrates poor tolerance to loaded knee flexion 1

• Provide education addressing pain not correlating with tissue damage, expected recovery timeframes, and load management strategies to build patient confidence and autonomy 1

Advanced Interventions if Conservative Management Fails

• Corticosteroid injection may be considered if there is significant effusion or inflammatory flare, though this provides only short-term relief without improving long-term outcomes 2, 3

• Extracorporeal shock wave therapy (ESWT) represents a safe, noninvasive option for chronic symptoms persisting beyond 3-6 months 2, 3

• Surgical consultation is warranted if symptoms persist after 6 months of appropriate conservative management 2

Critical Pitfalls to Avoid

• Joint effusions are uncommon with simple tendinopathy and suggest intra-articular pathology requiring imaging 2

• Complete immobilization must be avoided to prevent muscular atrophy and deconditioning 2, 3

• Beware of aberrant anatomy: In rare cases, hyperextension injuries with persistent lateral knee snapping may indicate aberrant biceps femoris anatomy requiring surgical intervention 5

• Patella infera can develop with certain treatment approaches and lead to patellofemoral complaints, requiring monitoring of patellar height 6

• The posterolateral and posteromedial capsular structures provide the majority (54.7%) of restraint against knee hyperextension, with cruciate ligaments contributing only 25.3%, so capsular injury should be suspected in significant hyperextension mechanisms 7

Monitoring Parameters

• Assess pain levels using Visual Analog Scale (VAS) at each visit 4

• Measure knee circumference at mid-patella, 5 cm above, and 5 cm below to objectively track swelling 4

• Document knee flexion and extension range of motion to monitor functional improvement 4

• Evaluate functional status using validated outcome measures to guide treatment progression 1

• Reassess at 1,2,3, and 4 weeks post-injury to ensure appropriate healing trajectory 8