What are the key clinical features to assess in a patient presenting with knee pain to differentiate between osteoarthritis and meniscal injury?

To differentiate between osteoarthritis (OA) and a meniscal injury in a patient presenting with knee pain, a thorough clinical assessment focusing on history and examination findings is crucial ².

Key features for Osteoarthritis (OA):

• A clinical diagnosis of knee OA can often be made without imaging if the patient is 45 years or older, has activity-related joint pain, and has either no morning joint stiffness or morning stiffness lasting no longer than 30 minutes ¹.
• Pain is typically activity-related and worsens with use ¹.
• Stiffness is commonly experienced in the morning, lasting less than 30 minutes, or after periods of rest ¹.
• Patients may report reduced function and difficulty with daily activities ¹.
• On examination, crepitus (a grating or crackling sound) may be felt or heard during knee movement ². An effusion (swelling due to fluid accumulation) may also be present ².

Key features for Meniscal Injury:

• A history of a specific twisting injury to the knee is often reported ².
• Patients commonly present with mechanical symptoms such as locking (the knee getting stuck), clicking, or giving way (sudden instability) ².
• Pain is often exacerbated by specific movements like squatting ².
• On examination, there may be tenderness along the joint line where the meniscus is located ². An effusion may also be present ².

Differentiation and Overlap:

• The presence of mechanical symptoms like locking, clicking, or giving way is highly suggestive of a meniscal injury and helps differentiate it from isolated OA ².
• While OA pain is typically more generalized and activity-related, meniscal pain can be more localized to the joint line and triggered by specific movements ¹,².
• Morning stiffness lasting less than 30 minutes is a hallmark of OA, whereas it is less characteristic of an isolated meniscal injury ¹.
• It is important to note that individuals can present with both osteoarthritis and symptomatic meniscal tears, which can collectively influence their reported pain and mobility [Luc-Harkey et al., 2018]. Therefore, a comprehensive assessment is vital to identify all contributing factors to the patient's knee pain ².