ALGORITHM FOR THE DIAGNOSIS AND TREATMENT OF KNEE DISORDERS FOR HEALTH CARE PROVIDERS

General Principles

• All patients should be referred to an orthopaedic surgeon within 1 week (or less) unless emergency referral is specified.
• All MRIs should be 1.5 or 3 Tesla, Never Open (unless it is 1.5 Tesla)
• Protected weight bearing should usually be with a walker. If Crutches are used, make sure the patient is young, lean and able to handle them, and understands that they must use two crutches, not just one. A cane is inadequate.
• Pain relief in the knee patient is accomplished by:
  • Protected weight bearing
  • Continuous ice to area (but not directly on the skin to avoid ice burn)
  • Acetaminophen if needed
  • Tramadol in addition to Acetaminophen if necessary
  • Never NSAIDs (aspirin, Aleve, Ibuprofen, Advil, etc)
  • Never opiates: unless the patient has a fracture or unusual circumstance (judicious hydrocodone, never oxycodone)

Which Knee X-Rays to Order:

• Under 50 years old – Bilateral standing AP, lateral, sunrise, and oblique if desired
• 50 years and over – Bilateral standing AP, lateral, and sunrise

Diagnosis and Treatment Algorithm

Red Color Below – Indicates likely Diagnosis

Blue Color Below – Indicates Recommended Initial Treatment

Emergent Injuries

X-Ray Positive for

• Knee Dislocation - Immediate 911 – Ambulance to Hospital ER
• Femoral Shaft or Unstable Tibial Shaft Fracture - Immediate 911, Ambulance to Hospital ER

Non-Emergent Injuries

X-Ray Positive for Stable Fracture

• Tibia Plateau or Femoral Condyle Fracture – Non weight bearing with walker/crutches - Brace locked in 40° flexion preferred, or knee immobilizer, or long leg splint: urgent referral to orthopaedic surgeon or ER.
• Patella Fracture – Touchdown weight bearing with walker/crutches in knee immobilizer: urgent referral to orthopaedic surgeon or ER.
• Tibial Tubercle Avulsion Fracture – Knee immobilizer touchdown weight bearing, urgent referral to orthopaedic surgeon or ER.

X-Ray Negative for Fracture

Tender Over the Tibial Plateau - Possible occult tibial plateau fracture - Non weight bearing, MRI scan, and orthopaedic referral within a week.

Not Tender over the Tibial Plateu

• Large Effusion
  • Redness, Pain with Minimal Motion, Temperature of at Least 100 Degrees, Drainage - Septic Arthritis - Drain knee with 18 or 16 gauge needle from proximal lateral location, send for gram stain cell count, culture and sensitivity and crystals. Start on Keflex 500 mg two tablets qid (Clindamycin 600mg tid if patient is penicillin allergic), Do Not Start Antibiotic Until the Knee is Drained for Culture. Draw blood for ESR, CRP, CBC with differential. Arrange to be Seen on the Same Day by an orthopaedist or ER.
  • No Redness, Pain with Minimal Motion, Fever, nor Drainage
    • Tender over the Medial Patella and a History Suggesting Patellar Dislocation - Patellar dislocation - Knee immobilizer, partial weight bearing.
    • Not Tender over Medial Patella, Cannot Do Straight Leg Raise - Quadriceps or Patellar Tendon Rupture - Knee immobilizer, partial weight bearing.
    • Not Tender over Medial Patella, Can Do Straight Leg Raise - ACL tear - Partial weight bearing, MRI, no immobilization.
    • History of Gout - Gout - Serum uric acid, CBC with differential, aspirate knee and send fluid for gram stain, culture, cell count and crystals. Give indomethacin or ibuprofen (my only NSAID indication).
• Small or No Effusion
  • Tender Medial Joint Line, Normal Standing AP Knee Joint Space and/or Age under 40, No valgus Laxity or Pain with Valgus Stress - Medial Meniscal Tear or Referred Patellofemoral Pain - Partial weight bearing, no immobilization.
  • Tender Lateral Joint Line, Normal Standing AP Knee Joint Space and/or Age under 40, Not Tender over LCL, No Varus Laxity in 40° of Knee Flexion - Lateral Meniscal Tear or Referred Patellofemoral Pain - Partial weight bearing if limping, no immobilization.
  • Tender over Lateral Collateral Ligament with Knee Flexed 40° and Varus Stress Applied, Positive Varus Laxity in 40° Knee Flexion - Lateral Collateral Ligament (LCL) Injury - Partial weight bearing, no immobilization.
  • Tender Medial or Lateral Joint Lines, Decreased Medial or Lateral Joint Space on Standing AP Views or Age over 50 - Arthrosis - Partial weight bearing, no immobilization.
  • Tender over Medial Epicondyle of Femur or Medial Tibia 4 finger breadths below the Joint Line More than Medial Joint Line Tenderness (with or without valgus laxity or pain to valgus stress) - MCL Sprain - Partial weight bearing, no immobilization.
  • Positive Patello-Femoral Crepitus Supine with Hip Flexed 90° and Normal Sunrise View - Chondromalacia Patellae - or Abnormal Sunrise View - Patellofemoral Arthrosis - Partial weight bearing, no immobilization.
  • No Patella-Femoral Crepitus and Tender over Infra-Patellar Border - Patellar Tendinitis - Partial weight bearing.
  • Tender over Tibial Tubercle, X-ray Shows Intact Although Possibly Fragmented Tibial Tubercle, Age 13-15 years - Osgood-Schlatter Syndrome - Partial weight bearing, knee immobilizer if severe.

Posterior Knee Pain – Difficult to Diagnose ("Baker's Cysts" do not produce pain unless they are very large), Posterior Pain is often Referred Pain from Patellofemoral Joint - Protected weight bearing if pain more than mild.