CHRISTOPHER W. BUNT, MD, CHRISTOPHER E. JONAS, DO, AND JENNIFER G. CHANG, MD
Am Fam Physician. 2018;98(9):576-585
Patient information: See related handout on knee pain.
Author disclosure: No relevant financial affiliations.
Knee pain affects approximately 25% of adults, and its prevalence has increased almost 65% over the past 20 years, accounting for nearly 4 million primary care visits annually. Initial evaluation should emphasize excluding urgent causes while considering the need for referral. Key aspects of the patient history include age; location, onset, duration, and quality of pain; associated mechanical or systemic symptoms; history of swelling; description of precipitating trauma; and pertinent medical or surgical history. Patients requiring urgent referral generally have severe pain, swelling, and instability or inability to bear weight in association with acute trauma or have signs of joint infection such as fever, swelling, erythema, and limited range of motion. A systematic approach to examination of the knee includes inspection, palpation, evaluation of range of motion and strength, neurovascular testing, and special (provocative) tests. Radiographic imaging should be reserved for chronic knee pain (more than six weeks) or acute traumatic pain in patients who meet specific evidence-based criteria. Musculoskeletal ultrasonography allows for detailed evaluation of effusions, cysts (e.g., Baker cyst), and superficial structures. Magnetic resonance imaging is rarely used for patients with emergent cases and should generally be an option only when surgery is considered or when a patient experiences persistent pain despite adequate conservative treatment. When the initial history and physical examination suggest but do not confirm a specific diagnosis, laboratory tests can be used as a confirmatory or diagnostic tool.
Knee pain affects approximately 25% of adults. The prevalence of knee pain has increased almost 65% over the past 20 years, accounting for nearly 4 million primary care visits annually. 1 , 2 The initial evaluation should emphasize excluding urgent causes while considering the need for referral. A standardized, comprehensive history and physical examination are crucial for differentiating the diagnosis. Nonsurgical problems do not require immediate definitive diagnosis. Imaging and laboratory studies can play a confirmatory or diagnostic role when appropriate. This article reviews the initial primary care office evaluation of undifferentiated knee pain in adults and adolescents (ages 11 to 17 years), highlighting key patient history and physical examination findings (Table 1 1 , 3 – 27 ). The uses of and indications for radiography, musculoskeletal ultrasonography, magnetic resonance imaging (MRI), and laboratory evaluation are also addressed.
| Clinical recommendation | Evidence rating | References | Comments |
|---|---|---|---|
| Internal derangement should be suspected in patients with knee trauma and acute effusion. | C | 3, 4, 6, 7, 11, 12, 14, 19, 30 | Rapidity of effusion should be noted. |
| In patients with suspected meniscal injury, the Thessaly test is preferred over the McMurray test or other evaluation for joint-line tenderness. | C | 3, 4, 6, 7, 12, 14, 16, 25, 30, 31, 34 | Thessaly may be difficult to perform in an acute setting because of pain and feeling of instability. |
| The Ottawa Knee Rule should be used to determine which patients with acute knee injury require imaging. | A | 11, 16, 17, 29, 30, 36 – 38 | — |
| Recommendation | Sponsoring organization |
|---|---|
| Avoid ordering knee magnetic resonance imaging for a patient with anterior knee pain without mechanical symptoms or effusion unless the patient has not improved after completion of an appropriate functional rehabilitation program. | American Medical Society for Sports Medicine |