Dr Kola Tytler MBBS CertHE MBA MRCGPClinical Lead • iatroX
For evaluating knee pain in primary care, imaging modalities are generally not routinely recommended for diagnosis or management of osteoarthritis (OA) unless specific criteria are met NICE NG226.
- Diagnosis of Osteoarthritis: OA can typically be diagnosed clinically without imaging in individuals aged 45 or over who have activity-related joint pain and morning stiffness lasting no longer than 30 minutes NICE NG226. Imaging should not be routinely used for diagnosis unless there are atypical features or signs suggesting an alternative or additional diagnosis NICE NG226.
- Management of Osteoarthritis: Imaging is not routinely used for follow-up or to guide non-surgical management of OA NICE NG226.
- Sprains and Strains: Magnetic Resonance Imaging (MRI) is considered the gold standard for imaging ligamentous and intra-articular structures of the knee NICE CKS. However, its routine use for acute injuries is limited by cost and availability NICE CKS. MRI should be reserved for cases of persistent symptoms in severe sprains or chronic instability to rule out osteochondral defects, missed syndesmotic injuries, or bony injuries not identified on X-ray NICE CKS.
- Specialised Assessment: Appropriately focused imaging for knee pain is in most cases better performed as part of further specialised assessment NICE CKS. Direct access to MRI may be available depending on local arrangements and criteria NICE CKS.
You should refer a patient for further investigation under the following circumstances:
- Urgent Referral (to be seen within 2 weeks):
- If a tumour is suspected NICE CKS,NICE NG12.
- If persistent synovitis of undetermined cause is suspected, especially if small joints of the hand or feet are affected, more than one joint is affected, or there has been a delay of 3 months or longer between symptom onset and seeking medical help NICE CKS. Refer urgently to a rheumatologist to assess for inflammatory polyarthritis NICE CKS.
- If a child or young person presents with suspected juvenile idiopathic arthritis, refer urgently to a paediatric rheumatologist and discuss immediate management with the on-call rheumatologist NICE CKS.
- If osteonecrosis of the knee is suspected, refer urgently to an orthopaedic surgeon NICE CKS.
- Immediate Assessment:
- If patellar dislocation occurs in a person with recurrent dislocation and is associated with moderate or severe swelling NICE CKS.
- If Henoch-Schönlein purpura is suspected NICE CKS.
- If a child presents with a limp NICE CKS.
- Referral for Further Assessment and/or Advice (to an integrated musculoskeletal service or orthopaedic surgeon):
- Persisting knee pain or other symptoms for more than six weeks NICE CKS.
- A suspected degenerative meniscal tear NICE CKS.
- Symptomatic bipartite patella NICE CKS.
- Fat pad impingement/inflammation NICE CKS.
- Plicae syndrome NICE CKS.
- Osteochondritis dissecans NICE CKS.
- Recurrent patellar dislocation/subluxation NICE CKS.
- Patellofemoral pain syndrome, particularly if not improved after 6 weeks of conservative management NICE CKS.
- Iliotibial band syndrome NICE CKS.
- Other Specific Referrals:
- If complex regional pain syndrome is suspected, refer to an appropriate specialist for confirmation of diagnosis, to rule out ongoing pathology, and for symptom control and rehabilitation NICE CKS.
- If the diagnosis is uncertain, consider referring to an appropriate specialist (e.g., rheumatologist, orthopaedic surgeon, sports physician, or other musculoskeletal specialist) NICE CKS.
- For osteoarthritis, consider referral to an orthopaedic surgeon if non-surgical management is unsuitable or ineffective after 3 months, especially if symptoms substantially impact the person's quality of life, there is diagnostic uncertainty or atypical features, or a sudden worsening of symptoms NICE CKS. The decision to refer for joint surgery should not be based on age, sex, smoking status, comorbidities, or BMI NICE CKS,NICE NG226.