Initial Evaluation and Treatment of Knee Pain in Adults Jose Yasul, MD April 29, 2009

Goals Make a decision and start treatment Knee / Shoulder anatomy Common pain patterns Frequently encountered causes Specific examination skills Imaging Labs Differential diagnosis

Disclosure Slide No relevant financial relationship exists to potential commercial bias

Musculoskeletal Numbers Back 23% Knee 19% Shoulder 16% Urwin M, Symmons D, Alison T, et al. Estimating the burden of musculoskeletal disorders in the community: the comparative prevalence of symptoms at different anatomical sites, and the relation to social deprivation. Ann Rheum Dis. 1998;57(11):

Knee Anatomy Bones Ligaments Menisci

History Time Course Mechanism of injury Pain characteristics Mechanical symptoms Effusion Medical History

Acute Onset (Questions I ask) Date of injury Mechanism Able to walk or continue activity immediately after injury Able to walk or bear weight since injury Effusion / bruising Mechanical symptoms 1 st injury? Prior lower extremity injuries

Focused Physical Exam Inspection and palpation Range of motion Ligaments Menisci Patellofemoral assessment Gait

Inspection and palpation / ROM Erythema, swelling, bruising, discoloration Musculature Pain, warmth, effusion Point tenderness Range of motion

Cruciate ligaments ACL >Anterior drawer >Lachman’s >Pivot Shift PCL >Posterior sag sign >Posterior drawer test

Collateral ligaments MCL – Valgus stress LCL – Varus stress Compare to uninjured side 0 and 30 degrees of flexion

Menisci Joint line tenderness McMurray’s test >Lateral meniscus – IR tibia + valgus stress >Medial meniscus – ER tibia + varus stress Ege's test – May be the most sensitive

Imaging (X-rays) Bilateral AP Weight bearing Lateral Merchant’s view

Knee Fractures Patella fractures Femoral condyle fractures Tibial eminence fractures Tibial tubercle fractures Tibial plateau fractures

Quadriceps Injuries Quadriceps contusion Quadriceps tendon sprain / rupture Quadriceps muscle partial tear Acute hamstring injuries tend to be more proximal Acute calf injuries tend to be more distal

ACL Non-contact deceleration Plant and sharp turn – Anterior displacement of tibia causes sprain or rupture of ACL “Pop” felt followed by pain causing patient to cease activity with swelling within 2 hrs

ACL Acutely moderate to severe joint effusion Guarding and hemearthrosis limits testing in the acute phase Lachman test X-ray – tibial spine avulsion MRI

MCL & LCL MCL more common than LCL Results from Valgus and varus stress respectively Tenderness at respective joint line Valgus/varus stress at 0 & 30º reproduce pain (+) endpoint grade I/II sprain (-) endpoint grade III sprain

Meniscal tear Sudden twisting injury or a prolonged degenerative process Recurrent locking with squatting / twisting Tender joint line Quad atrophy McMurray testing / Ege’s testing MRI

Septic arthritis More common in immune compromised Abrupt onset of pain Warm, swollen, and exquisitely tender MINIMAL motion causes INTENSE pain Arthrocentesis -WBC > 50,000/mm 3 - Gram stain – Staph, Strep, Gonorrhea Blood – Elevated WBC, ESR, CRP

Make a Decision - DDx Knee contusion Fracture Muscle / tendon strain or rupture Ligament strain or rupture Meniscal injury Infection Exacerbation of chronic knee pain

Treatment goals Stabilize knee Prevent further injury Regain full function Cause no harm

Treatments Reassurance Limit activity / RICE Braces and immobilizers Crutches and canes (weight bearing status) Home exercise program Pain meds (Do not prevent further injury) Follow up Further imaging Consultation / Referrals / admission

Chronic Onset (Questions I ask) How long? What were you doing when pain first noticed Prior injuries Pain all the time or come and go Swelling Mechanical symptoms What makes it better / worse (Theatre sign) Treatments? (Rehab, bracing, meds)

Physical Examination Inspection and palpation Range of motion Ligaments Menisci Patellofemoral assessment Feet & Shoes

Patellofemoral assessment Patient supine and knee in extension Effusion in suprapatellar pouch Tracking of patella Crepitus VMO tone Patella apprehension test Patellar grind

Feet & Shoes Pes planus Posterior tibia tendon dysfunction Treadwear Solid sole

Imaging Adults 3 views >AP >Lateral >Merchant’s or Sunrise (Note: Teens, add notch or tunnel view )

Labs ? Of septic arthritis >Blood – CBC-d, ESR, CRP >Joint fluid -cell count with differential -glucose & protein -bacterial culture Simple joint effusion Hemearthrosis Fat globules

Differential Diagnosis Patellofemoral pain syndrome Medial plica syndrome Pes anserine bursitis Trauma – ligament sprains or meniscal tear Inflammatory arthropathy Septic arthritis

Older adults Osteoarthritis Crystal induced inflammatory arthropathy Gout, pseudogout Popliteal cyst (Baker’s cyst)

Patellofemoral syndrome (chondromalacia) The most common diagnosis in outpatients presenting with knee pain Anterior pain - mild to moderate severity “Theater sign” Poorly localized “Circle sign” “Knee giving way” A final common pathway

Osteoarthritis Aggravated by weight bearing and relieved by rest No systemic symptoms, morning stiffness Episodes of acute synovitis PE reveals decreased ROM, crepitus, mild joint effusion, possibly palpable osteophytes

Osteoarthritis X-rays – Wt bearing AP, lateral, Merchant Joint space narrowing Subchondral bony sclerosis Cystic changes osteophytes

Crystal induced inflammatory arthropathy Gout – Sodium urate crystals precipitate and cause inflammatory response Pseudogout – Calcium pyrophosphate PE – Red, warm, swollen, tender Arthrocentesis WBC – 2,000 to 75,000 per mm 3 Protein – high (>32g/dL) Glucose – 75% of serum

Gout Crystals

Pseudogout – Calcium pyrophosphate CPPD crystals in the fluid rhomboid or rod- shaped, weakly positively birefringent crystals on polarized light microscopy of synovial fluid

Medial plica syndrome Frequently overlooked source of medial knee pain Redundant joint synovium inflamed with repetitive overuse Tender, mobile nodularity medial aspect of knee just anterior to the joint line Medial knee pain Worse with repetitive flexion and extension

Pes anserine bursitis Medial knee pain Worse with repetitive flexion and extension Exam >No effusion >tenderness just post. & distal to med jt line >Pain reproduced by valgus stress or resisted knee flexion

Popliteal cyst (Baker’s cyst) Mild to moderate pain in popliteal area The most common synovial cyst Usually a response to preceding trauma Posteromedial aspect at the level of the gastrocnemiosemimembranous bursa Palpable fullness posteromedially McMurray test may be positive

Popliteal cyst (Baker’s cyst) Definitive diagnosis of a popliteal cyst may be made with arthrography, ultrasonography, CT scanning, or, less commonly, MRI

Make a Decision - DDx Patellofemoral pain syndrome Osteoarthritis Crystal induced inflammatory arthropathy Gout, pseudogout Trauma – ligament sprains or meniscal tear Medial plica syndrome Pes anserine bursitis Septic arthritis Popliteal cyst (Baker’s cyst)

Treatments Reassurance Limit activity Braces and immobilizers Crutches and canes (weight bearing status) Home exercise program Pain meds (Do not prevent further injury) Steroids (Oral or injectable) Follow up Further imaging Consultation / Referrals / admission

The role of the physician is to entertain the patient while Nature takes its course. Voltaire