MARCH 2014 Approach to the Adult with Knee Pain

Objectives Broadly categorize knee pain Identify most common differential diagnosis of knee pain

Knee Pain TraumaticNon –Traumatic IntrinsicExtrinsic PeriarticularIntraarticular StructuralInflammatory

Anatomy

Clinical Question 57 yo M with PMH of Hypertension, Diabetes presents with right knee pain started 3 months ago. He noticed his knee slowly became more red and swollen. He works in an office and sits most of the day. He does not recall any trauma. He likes to walk with his wife in the evenings and occasionally does gardening on the weekends. He denies any fevers, rash or pain in other joints. On physical exam there is no click, there is full range of motion however painful and with tenderness to palpation on the medial aspect of knee. What condition does he most likely have?  Iliotibial band syndrome  Prepatellar Bursitis  Meniscal tear  Patellofemoral pain syndrome

Step 1: Intrinsic vs Extrinsic Knee motion rarely aggravates referred pain If examination of knee is normal. Test hip and ankle to identify referred pain

Step 2: Periarticular versus Intraarticular Intra-articular - structural defect or an inflammatory process  patient experiences discomfort within the knee  often a chronic effusion is present and tenderness is diffuse Peri-articular – patient’s can localize the pain to a specific area around the knee  Specific examination maneuvers (direct palpation, valgus or varus stress) elicit a focal pain at the involved structure

Varus and Valgus Stress Tests

Periarticular Pain by Location LocationMost common diagnoses Anterior MCL and Pes Anserine Bursitis Medial patellofemoral pain syndrome, prepatellar bursitis Lateral lateral collateral ligament injury, iliotibial band syndrome Posterior Popliteal (Baker’s Cyst), joint effusion

Intraarticular Knee Pain: Step 3: Inflammatory vs Structural Structural – pain is usually provoked by activity and is absent at rest  Meniscal tear, ACL tear  Inflammatory process -pain with activity AND at rest o Often presents with joint effusion and fluid analysis is needed by aspiration of the effusion

Common Causes of Intra-articular Knee Pain StructuralInflammatory Meniscal InjurySeptic arthritis ACL injuryGout PCL injuryReactive arthritis Knee Dislocation Fractures Osteonecrosis Osteoarthritis

Knee Pain TraumaticNon –Traumatic IntrinsicExtrinsic PeriarticularIntraarticular StructuralInflammatory Referred from other joints like hip, ankle, back Focal pain, Ddx based on location Pain with activity Pain with rest and activity

Summary Use the step wise algorithm in your approach to creating a differential diagnosis Localization of the pain can help narrow the differential

References Up to Date: General evaluation of the adult with knee pain MKSAP 16 Rheumatology MKSAP 16 General Internal Medicine MedStudy 15 th Edition Core curriculum Book 3 Rheumatology