What is the appropriate assessment and plan (A/P) for a patient with unspecified right knee pain without trauma?

Assessment and Plan for Unspecified Right Knee Pain Without Trauma

Assessment

For atraumatic knee pain, the most likely diagnoses are osteoarthritis (especially if age ≥45 years), patellofemoral pain syndrome (especially if age <40 years and physically active), or degenerative meniscal pathology. 1

Clinical Evaluation

Key history elements to document:

• Age - OA is most likely in patients ≥45 years with activity-related pain and <30 minutes of morning stiffness (95% sensitivity, 69% specificity) 1
• Pain pattern - Anterior knee pain during squatting suggests patellofemoral pain (91% sensitivity, 50% specificity) 1
• Functional limitations - Weight-bearing ability, presence of effusion, and focal tenderness guide imaging decisions 2
• Rule out referred pain - Consider hip or lumbar spine pathology if knee examination is unremarkable 2, 3

Physical examination findings to assess:

• Joint line tenderness - 83% sensitivity and specificity for meniscal pathology 1
• McMurray test - Concurrent knee rotation with extension (61% sensitivity, 84% specificity for meniscal tears) 1
• Effusion presence - Indicates need for imaging per Ottawa criteria 2
• Patellar tracking and anterior knee pain reproduction 1

Diagnostic Imaging

Initial radiographs are appropriate for chronic knee pain to evaluate for degenerative changes, and should include anteroposterior, lateral, and tangential patellar views. 4, 2

• Radiographs should be obtained for chronic atraumatic knee pain to assess for OA 4
• Do not order MRI as initial imaging - MRI should only be considered when surgery is contemplated, pain persists despite adequate conservative treatment, or initial radiographs are normal but symptoms persist 4, 2
• Meniscal tears on MRI are often incidental findings in older patients and should not drive treatment decisions 2

Plan

First-Line Conservative Management

Exercise therapy, patient education, and self-management programs are the cornerstone of treatment for all common causes of atraumatic knee pain. 1, 5

For suspected osteoarthritis (age ≥45 years):

• Exercise therapy - Structured strengthening and aerobic exercise program 6, 1
• Weight loss if BMI >25 - Critical component of OA management 1
• Patient education - Diagnosis explanation and activity modification 1, 7
• NSAIDs when not contraindicated - Oral NSAIDs for symptomatic relief (high quality evidence, strong recommendation) 6
• Acetaminophen may be considered when NSAIDs contraindicated (consensus evidence) 6
• Physical therapy referral - Can be considered for mild-to-moderate symptomatic OA (high quality evidence, moderate strength recommendation) 6

For suspected patellofemoral pain (age <40 years, anterior knee pain):

• Hip and knee strengthening exercises combined with foot orthoses or patellar taping 1
• No indication for surgery in patellofemoral pain 1

For suspected degenerative meniscal tear:

• Exercise therapy for 4-6 weeks is first-line treatment 1
• Surgery is not indicated for degenerative meniscal tears, even with mechanical symptoms like locking or catching 1

Pharmacologic Adjuncts

• Oral NSAIDs when not contraindicated for symptomatic relief 6
• Intra-articular corticosteroid injections for symptomatic effusions (judicious use as monotherapy or adjunct) 5, 8
• Hyaluronic acid infiltrations are conditionally recommended 5

Follow-up and Escalation

• Reassess in 4-6 weeks after initiating conservative management 1
• Consider MRI only if pain persists despite adequate conservative treatment or if surgery is being contemplated 4, 2
• Orthopedic referral for end-stage OA (minimal joint space, inability to cope with pain) after exhausting conservative options 1, 8

Key Pitfalls to Avoid

• Do not rush to imaging before completing thorough clinical examination 3
• Do not order MRI without recent radiographs - occurs in ~20% of chronic knee pain cases 2
• Do not perform surgery for degenerative meniscal tears - exercise therapy is first-line even with mechanical symptoms 1
• Do not overlook referred pain from hip or lumbar spine pathology 2, 3