Summary of intervention
Patients who have knee pain with persistent mechanical symptoms (locking, catching and intermittent sudden pain on movement) that has not responded to three months of initial non-operative care may have a symptomatic meniscal tear. These patients are referred to intermediate or secondary care and in these circumstances an MRI scan is the best investigation to determine the cause of symptoms.
Patients who have a clear history of a significant acute knee injury and mechanical symptoms or who have a locked knee require referral to intermediate or secondary care and should undergo MRI investigation.
The majority of patients who present to primary care with knee pain do not require initial investigation with an MRI scan once red flag symptoms and signs have been excluded.
This guidance applies to adults aged 19 years and over.
Number of interventions 2018/19
Currently there is no diagnostic data in outpatients so indication for knee MRI is not clear, therefore the number of interventions (80,315) represents the total number of knee MRIs
Patients with a clear history of a significant acute knee injury and mechanical symptoms or who have a locked knee may have a repairable meniscal tear and should undergo referral to intermediate or secondary care and have MRI investigation.
The majority of patients who initially present in primary care with knee symptoms, no red flags and no history of acute knee injury or a locked knee do not need an MRI investigation and can be treated with non-operative supportive measures. Patients with persistent mechanical knee symptoms should be referred to secondary care and should have an MRI scan of the knee to investigate for a meniscal tear and/or other pathology.
Rationale for recommendation
Degenerate meniscal tears and OA are extremely common in the general population. MRI is not recommended for a suspected degenerative meniscal tear unless there are mechanical symptoms (e.g. locking) or lack of improvement with conservative treatment (e.g. exercise/therapy, weight loss, bracing, topical or oral analgesia). Acute knee injury can result in meniscal pathology that may require surgical intervention such as meniscal repair and an MRI scan is the investigation of choice in these cases. A locked knee requires urgent assessment and an MRI scan is the investigation of choice to define the cause.