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Knee MRI when symptoms are suggestive of osteoarthritis

Knee MRI when symptoms are suggestive of osteoarthritis

Best Practice Guidance


Osteoarthritis (OA), the most common form of arthritis, is characterised by joint pain accompanied by a varying degree of functional limitation and reduced quality of life. The most commonly affected joints are the knees, hips and small hand joints with a poor link between changes visible on a radiograph and symptoms of osteoarthritis.

An initial diagnosis of OA can be made when clinical assessment is suggestive of this pathology. If imaging is required to confirm the diagnosis, then weight bearing radiographs are the first-line of investigation. Magnetic resonance imaging (MRI) for knees is not usually needed.


This guidance applies to adults aged 19 years and over.


In primary care, where clinical assessment is suggestive of knee OA, imaging is not usually necessary. If imaging is required then weight bearing radiographs are the first-line of investigation. Patients with persistent symptoms should, after three to four months, be referred to secondary care and should have imaging of the knee to investigate for OA and/or other pathology.

Where imaging is necessary, in secondary care the first-line investigation of potential knee OA is weight bearing plain radiography. If the patient has a pattern of disease that allows surgical treatment to be adequately planned with plain radiographs, then MRI is not required.

However, there are a number of situations where MRI of the osteoarthritic knee can be useful:

  • Patients who have severe symptoms but relatively mild OA on standard X-rays. In this situation the MRI offers more detail and can show much more advanced OA or Osteonecrosis within the knee
  • In working up a patient for possible HTO or partial knee replacement an MRI can be a very useful investigation focusing on the state of the anterior cruciate ligament and state of the retained compartments.

In summary an MRI scan can be a useful investigation in the contemporary surgical management of osteoarthritis, giving critical information on the pattern of disease and state of the soft tissues. However, requesting an MRI scan when it is not indicated potentially prolongs further waiting times for patients, can cause unnecessary anxiety while waiting for specialist consultation and can delay MRI scans for appropriate patients.


Rationale for recommendation

The diagnosis of knee OA can be effectively made in primary care based upon the patient’s history and physical examination. In particular, NICE recommends diagnosing osteoarthritis clinically, and without investigations, in patients who:

  • Are 45 or over AND
  • Have activity-related joint pain AND
  • Has either no morning joint-related stiffness or morning stiffness that lasts no longer than 30 minutes.

It is important to exclude other diagnoses in some cases where there may be atypical features which may indicate alternative or additional diagnoses such as:

  • A history of trauma
  • History of cancer or corresponding risk factors
  • Prolonged morning joint-related stiffness
  • Rapid worsening of symptoms
  • The presence of a hot swollen joint.

Important differential diagnoses include gout, other inflammatory arthritides (for example, rheumatoid arthritis), septic arthritis and malignancy (bone pain).

In secondary care when surgical intervention for OA is being considered an MRI scan can offer valuable information about the pattern of disease within the knee. This includes planning for osteotomy around the knee for OA and for partial knee replacement, where in both cases information about the state of the preserved compartments and the anterior cruciate ligament are critical to the surgical plan.

A meta-analysis published in 2017 assessing the role of MRI in OA assessed 16 studies, which included 1220 patients. It found that MRI can detect OA with an overall high specificity and moderate sensitivity so better used to exclude OA than to confirm it. The study recommended that standard clinical algorithm for OA diagnosis, aided by radiographs is the most effective method for diagnosing OA.

The European League Against Rheumatism (EULAR) conducted a systematic review including 390 studies leading to seven recommendations concerning the use of imaging in peripheral joint OA as below:

  • Imaging is not required to make the diagnosis in patients with typical presentation of OA. Level of evidence: III–IV. LOA (95% CI) 8.7 (7.9 to 9.4)
  • In atypical presentations, imaging is recommended to help confirm the diagnosis of OA and/or make alternative or additional diagnoses. Level of evidence: IV. LOA (95% CI) 9.6 (9.1 to 10)
  • Routine imaging in OA follow-up is not recommended. However, imaging is recommended if there is unexpected rapid progression of symptoms or change in clinical characteristics to determine if this relates to OA severity or an additional diagnosis. Level of evidence: III–IV. LOA (mean, 95% CI) 8.8 (7.9 to 9.7)

If imaging is needed, conventional (plain) radiography should be used before other modalities. To make additional diagnoses, soft tissues are best imaged by US or MRI and bone by CT or MRI. Level of evidence: III–IV. LOA (95% CI) 8.7 (7.9 to 9.6).

  • Consideration of radiographic views is important for optimising detection of OA features; in particular for the knee, weightbearing and patellofemoral views are recommended. Level of evidence: III. LOA (95% CI) 9.4 (8.7 to 9.9)
  • According to current evidence, imaging features do not predict nonsurgical treatment response and imaging cannot be recommended for this purpose. Level of evidence: II–III. LOA (95% CI) 8.7 (7.5 to 9.7)
  • The accuracy of intra-articular injection depends on the joint and on the skills of the practitioner and imaging may improve accuracy. Imaging is particularly recommended for joints that are difficult to access due to factors including site (e.g., hip), degree of deformity and obesity. Level of evidence: III–IV. LOA (95% CI) 9.4 (8.9 to 9.9).


Patient information

There is no specific EBI patient guidance for this intervention.

However, we recommend using the BRAN principles (Benfits, Risks, Alternatives and do Nothing) when speaking with patients about this.

Further information on patient involvement in EBI can be found on the EBI for patients section.


Code Script

Coding and count merged for T Knee MRI when symptoms are suggestive of osteoarthritis and U Knee MRI for suspected meniscal tears, producing a
single metric.

WHEN LEFT(opa.Der_Procedure_All,4) in ('U133','U211’)
AND (opa.Der_Procedure_All like '%Z846%’ 
OR opa.Der_Procedure_All like '%O132%’)
AND (not ( opa.der_diagnosis_all like '%M00[01289]%’
OR opa.der_diagnosis_all like '%M01[01234568]%’
OR opa.der_diagnosis_all like '%M0[25][012389]%’
OR opa.der_diagnosis_all like '%M03[0126]%’
OR opa.der_diagnosis_all like '%M0[68][0123489]%’
OR opa.der_diagnosis_all like '%M07[0-6]%’
OR opa.der_diagnosis_all like '%M09[0128]%’
OR opa.der_diagnosis_all like '%M10[012349]%’
OR opa.der_diagnosis_all like '%M11[01289]%’
OR opa.der_diagnosis_all like '%M12[0123458]%’
OR opa.der_diagnosis_all like '%M13[0189]%’
OR opa.der_diagnosis_all like '%M14[01234568]%’
OR opa.der_diagnosis_all like '%M15[12348]%’
OR opa.der_diagnosis_all like '%M16[012345679]%’
OR opa.der_diagnosis_all like '%M17[2345]%’
OR opa.der_diagnosis_all like '%M238%’
OR opa.der_diagnosis_all like '%C40[289]%’
OR opa.der_diagnosis_all like '%C7[69]5%’
OR opa.der_diagnosis_all like '%D162%’)
OR opa.der_diagnosis_all IS NULL)
AND ISNULL(opa.Age_at_Start_of_Episode_SUS,opa.Der_Age_at_CDS_Activity_Date) between 19 AND 120 
THEN 'C_knee_arth'

Code Definitions

Procedure codes (OPCS)

U133 Magnetic resonance imaging of bone
U211 Magnetic resonance imaging NEC
Z846 Knee joint (secondary to U code)
O132 Knee NEC (secondary to U code)

Diagnosis codes (ICD)

M150 Primary generalized (osteo)arthrosis
M159 Polyarthrosis, unspecified
M170 Primary gonarthrosis, bilateral
M171 Other primary gonarthrosis
M179 Gonarthrosis, unspecified
M232 Derangement of meniscus due to old tear or injury
S832 Tear of meniscus, current
M000 Staphylococcal arthritis and polyarthritis
M001 Pneumococcal arthritis and polyarthritis
M002 Other streptococcal arthritis and polyarthritis
M008 Arthritis and polyarthritis due to other specified bacterial agents
M009 Pyogenic arthritis, unspecified
M010 Meningococcal arthritis
M011 Tuberculous arthritis
M012 Arthritis in Lyme disease
M013 Arthritis in other bacterial diseases classified elsewhere
M014 Rubella arthritis
M015 Arthritis in other viral diseases classified elsewhere
M016 Arthritis in mycoses
M018 Arthritis in other infectious and parasitic diseases classified elsewhere
M020 Arthropathy following intestinal bypass
M021 Postdysenteric arthropathy
M022 Postimmunization arthropathy
M023 Reiter disease
M028 Other reactive arthropathies
M029 Reactive arthropathy, unspecified
M030 Postmeningococcal arthritis
M031 Postinfective arthropathy in syphilis
M032 Other postinfectious arthropathies in diseases classified elsewhere
M036 Reactive arthropathy in other diseases classified elsewher
M050 Felty syndrome
M051 Rheumatoid lung disease
M052 Rheumatoid vasculitis
M053 Rheumatoid arthritis with involvement of other organs and systems
M058 Other seropositive rheumatoid arthritis
M059 Seropositive rheumatoid arthritis, unspecified
M060 Seronegative rheumatoid arthritis
M061 Adult-onset Still disease
M062 Rheumatoid bursitis
M063 Rheumatoid nodule
M064 Inflammatory polyarthropathy
M068 Other specified rheumatoid arthritis
M069 Rheumatoid arthritis, unspecified
M070 Distal interphalangeal psoriatic arthropathy
M071 Arthritis mutilans
M072 Psoriatic spondylitis
M073 Other psoriatic arthropathies
M074 Arthropathy in Crohn disease [regional enteritis]
M075 Arthropathy in ulcerative colitis
M076 Other enteropathic arthropathies
M080 Juvenile rheumatoid arthritis
M081 Juvenile ankylosing spondylitis
M082 Juvenile arthritis with systemic onset
M083 Juvenile polyarthritis (seronegative)
M084 Pauciarticular juvenile arthritis
M088 Other juvenile arthritis
M089 Juvenile arthritis, unspecified
M090 Juvenile arthritis in psoriasis
M091 Juvenile arthritis in Crohn disease [regional enteritis]
M092 Juvenile arthritis in ulcerative colitis
M098 Juvenile arthritis in other diseases classified elsewhere
M100 Idiopathic gout
M101 Lead-induced gout
M102 Drug-induced gout
M103 Gout due to impairment of renal function
M104 Other secondary gout
M109 Gout, unspecified
M110 Hydroxyapatite deposition disease
M111 Familial chondrocalcinosis
M112 Other chondrocalcinosis
M118 Other specified crystal arthropathies
M119 Crystal arthropathy, unspecified
M120 Chronic postrheumatic arthropathy [Jaccoud]
M121 Kaschin-Beck disease
M122 Villonodular synovitis (pigmented)
M123 Palindromic rheumatism
M124 Intermittent hydrarthrosis
M125 Traumatic arthropathy
M128 Other specific arthropathies, not elsewhere classified
M130 Polyarthritis, unspecified
M131 Monoarthritis, not elsewhere classified
M138 Other specified arthritis
M139 Arthritis, unspecified
M140 Gouty arthropathy due to enzyme defects and other inherited disorders
M141 Crystal arthropathy in other metabolic disorders
M142 Diabetic arthropathy
M143 Lipoid dermatoarthritis
M144 Arthropathy in amyloidosis
M145 Arthropathies in other endocrine, nutritional and metabolic disorders
M146 Neuropathic arthropathy
M148 Arthropathies in other specified diseases classified elsewhere
M151 Heberden nodes (with arthropathy)
M152 Bouchard nodes (with arthropathy)
M153 Secondary multiple arthrosis
M154 Erosive (osteo)arthrosis
M158 Other polyarthrosis
M160 Primary coxarthrosis, bilateral
M161 Other primary coxarthrosis
M162 Coxarthrosis resulting from dysplasia, bilateral
M163 Other dysplastic coxarthrosis
M164 Post-traumatic coxarthrosis, bilateral
M165 Other post-traumatic coxarthrosis
M166 Other secondary coxarthrosis, bilateral
M167 Other secondary coxarthrosis
M169 Coxarthrosis, unspecified
M172 Post-traumatic gonarthrosis, bilateral
M173 Other post-traumatic gonarthrosis
M174 Other secondary gonarthrosis, bilateral
M175 Other secondary gonarthrosis
M238 Other internal derangements of knee (code for knee locking but not specific to this)
C402 Malignant neoplasm: Long bones of lower limb
C408 Malignant neoplasm: Overlapping lesion of bone and articular cartilage of limbs
C409 Malignant neoplasm: Bone and articular cartilage of limb, unspecified
C765 Malignant neoplasm of other and ill-defined sites: Lower limb
C795 Secondary malignant neoplasm of bone and bone marrow
D162 Benign neoplasm: Long bones of lower limb

Additional Exclusions
apcs.der_diagnosis_all not like '%C[0-9][0-9]%' and 
apcs.der_diagnosis_all not like '%D0%' and 
apcs.der_diagnosis_all not like '%D3[789]%' and
apcs.der_diagnosis_all not like '%D4[012345678]%’

This code captures code in the ranges C00-C99, D00-D09 and D37-D48.
Age range: the codes use the following age ranges 0-18 for children and 19-120
for adults.
— Private Appointment Exclusion
AND apcs.Administrative_Category<>’02’


  1. NICE clinical guideline (2014) Osteoarthritis: care and management [CG177]
  2. Menashe L, et al. The diagnostic performance of MRI in osteoarthritis: a systematic review and meta-analysis. Osteoarthritis Cartilage. 2012 Jan;20(1):13-21. PMID: 22044841.
  3. Sakellariou G, et al. EULAR recommendations for the use of imaging in the clinical management of peripheral joint osteoarthritis. Ann Rheum Dis. 2017 Sep;76(9):1484-1494. PMID: 28389554.

How up to date is this information?

Last revised December 2023


December 2023 - Coding updated. August 2022 - Coding updated