Lower Extremity MRI (Foot, Ankle, Knee, Leg or Hip MRI) - CAM 721HB
GENERAL INFORMATION
It is an expectation that all patients receive care/services from a licensed clinician. All appropriate supporting documentation, including recent pertinent office visit notes, laboratory data, and results of any special testing must be provided. If applicable: All prior relevant imaging results and the reason that alternative imaging cannot be performed must be included in the documentation submitted.
Where a specific clinical indication is not directly addressed in this guideline, medical necessity determination will be made based on widely accepted standard of care criteria. These criteria are supported by evidence-based or peer-reviewed sources such as medical literature, societal guidelines and state/national recommendations.
Policy
INDICATIONS FOR LOWER EXTREMITY MRI (FOOT, ANKLE, KNEE, LEG or HIP)
Pre-condition
Plain radiographs must precede MRI evaluation unless otherwise indicated.
Joint or Muscle Pain (1,2,3)
Negative Findings on Orthopedic Exam and after X-Ray Completed
NOTE: Does not apply to young children (up to age 12)
- Persistent joint or musculotendinous pain unresponsive to conservative treatment," within the last 6 months which includes active medical therapy (physical therapy, chiropractic treatments, and/or physician supervised exercise**) of at least four (4) weeks
- With progression or worsening of symptoms during the course of conservative treatment
Joint Specific Provocative Exam Tests and Suspected Injuries (4)
Approvable Orthopedic Test
With a positive orthopedic sign, an initial x-ray is always preferred; however, it is not required to approve advanced imaging UNLESS otherwise specified in bold below. Any test that suggests joint instability requires further imaging (the below list is not all inclusive)
Ankle (5,6)
- Syndesmotic injury (high ankle injury) with tenderness to palpation over the syndesmosis (AITFL – anterior inferior tibiofibular ligament) and any of the following:(7,8)
- Positive stress X-rays
- Squeeze test
- Cotton test
- Dorsiflexion external rotation test
- Unstable lateral injury to ATFL (anterior talofibular ligament) with suspicion of a possible associated fracture around the ankle or a possible osteochondral injury of the talus and any ONE of the following:(9)
- Positive stress x-rays
- Positive anterior drawer test with non-diagnostic or inconclusive X-rays
- Positive posterior drawer test with non-diagnostic or inconclusive X-rays
- Achilles tendon tear(10)
- Thompson test or palpable partial or complete Achilles defect on physical examination
Knee (11,12)
- Anterior cruciate ligament (ACL) Injury(13)
- Positive testing:
- Anterior drawer
- Lachman’s
- Pivot shift test
- Positive testing:
- Suspected ACL Rupture - acute knee injury with physical exam limited by pain and swelling AFTER initial x-ray completed with any of the following (14)
- Based on mechanism of injury, i.e., twisting, blunt force
- Normal x-ray:
- Based on mechanism of injury, i.e., twisting, blunt force
OR
- Anyone of the following:
- Extreme pain
- Instability to stand
- Audible pop at time of injury
- Very swollen joint with inability to perform the physical exam
OR
- Abnormal x-ray:
- Large knee effusion on x-ray
- Acute mechanical locking of the knee not due to guarding(15)
- Meniscal injury/tear (A positive test is denoted by pain or audible/palpable clunk)(16)
- McMurray’s Compression
- Apley’s
- Thessaly test
- Patellar dislocation (acute or recurrent)(17)
- Positive patellofemoral apprehension test
- Radiographic findings compatible with a history of patellar dislocation (i.e., lipohemarthrosis or osteochondral fracture)
- Posterior cruciate ligament (PCL) injury
- Posterior drawer
- Posterior tibial sag (Godfrey or step-off test)
- Medial collateral ligament tear
- Positive valgus stress testing/laxity
- Lateral Collateral ligament tear
- Positive Varus stress testing/laxity
Hip
- Femoroacetabular impingement (FAI) / Labral tear(18,19,20)
- Anterior Impingement sign (aka FADIR test) (Hip or groin pain with flexion, adduction, and internal rotation)
- Posterior Impingement sign (Pain with hip extension and external rotation on exam)
- Persistent hip mechanical symptoms (after initial radiographs completed) including clicking, locking, catching, giving way or hip instability with a clinical suspicion of labral tear and/or radiographic findings suggestive of FAI (i.e., cross over sign, pistol grip deformity, alpha angle over 50 degrees) and suspected labral tear
- Determine candidacy for hip preservation surgery for known FAI
NOTE: For evaluation of both hips when the patient meets hip MRI guidelines (x-ray + persistent pain unresponsive to conservative treatment) for both the right and left hip, Evolent Clinical Guideline 037 for Pelvis MRI is the preferred study.
- Labral tear is suspected and fulfills above criteria, then bilateral hip MRIs are the preferred studies (not Pelvis MRI)
- Bilateral hip arthrograms are requested and otherwise meet guidelines, bilateral hip MRIs are the preferred studies (not Pelvis MRI)
Tendon Rupture (21,22)
After X-Ray and not Listed Above
High clinical suspicion of specific tendon rupture based on mechanism of injury and physical findings (i.e., palpable defect in quadriceps or patellar tendon rupture)
Trauma
Bone Fracture
- Hip and Femur(23)
- Suspected occult, stress or insufficiency fracture with a negative or non- diagnostic initial x-ray
- Approve an immediate MRI (no follow up radiographs required)- MRI preferred test
- Suspected occult, stress or insufficiency fracture with a negative or non- diagnostic initial x-ray
- Suspicion of a hip fracture in a pregnant patient does not require an initial x-ray
- Non-hip extremities: Suspected occult, stress, or insufficiency fracture(24)
- If x-rays, taken 10-14 days after the injury or clinical assessment, are negative or non-diagnostic
- If at high risk for a complete fracture with conservative therapy (e.g., navicular bone), then immediate MRI is warranted
- Pathologic or concern for impending fracture on x-ray or CT(24) – approve immediate MRI
- Suspected ligamentous/tendon injury with known fractures on x-ray/CT that may require surgery
- Nonunion or delayed union as demonstrated by no healing between two sets of x- rays. If a fracture has not healed by 4-6 months, there is delayed union. Incomplete healing by 6-8 months is nonunion, CT is the preferred study(25)
Osteochondral Lesions (12,26,27)
Defects, Fractures, Osteochondritis Dissecans
Clinical suspicion based on mechanism of injury and physical findings
NOTE: X-ray completed
Joint Prosthesis/Replacement (28)
Suspected joint prosthesis loosening, or dysfunction, (i.e., pseudotumor formation) after initial x-rays
- Suspected Metallosis with painful metal on metal hip replacement(29) after initial x- rays
Extremity Mass (30)
- Mass or lesion after non-diagnostic x-ray or ultrasound. CT is better than MRI to evaluate mass calcification or bone involvement and may complement or replace MRI
- Baker’s cyst should be initially evaluated with ultrasound
- Superficial mass, then ultrasound is the initial study
- Deep mass, then x-ray is the initial study
- Vascular malformations(31)
- After initial evaluation with ultrasound and results will change management
- Inconclusive ultrasound
- Preoperative planning
- MRA is also approvable
- Follow up after treatment/embolization
Known Primary Cancer of the Extremity (32,33,34,35)
- Initial staging primary extremity tumor
- Follow-up of known primary cancer of patient undergoing active treatment within the past year or as per surveillance imaging guidance for that cancer
- Signs or symptoms or imaging findings suspicious for recurrence
- Suspected metastatic disease with signs/symptoms and after initial imaging with radiographs
Further Evaluation of Indeterminate Findings on Prior Imaging
Unless follow-up is otherwise specified within the guideline
- For initial evaluation of an inconclusive finding on a prior imaging report that requires further clarification
- One follow-up exam of a prior indeterminate MR/CT finding to ensure no suspicious interval change has occurred. (No further surveillance unless specified as highly suspicious or change was found on last follow-up exam.)
Osteonecrosis (36,37)
- To further characterize a prior abnormal x-ray or CT suggesting osteonecrosis
- Normal or indeterminate X-rays, but symptomatic and high risk (such as glucocorticosteroid use, renal transplant, glycogen storage disease, alcohol abuse, sickle cell anemia)
- Known osteonecrosis to evaluate a contralateral joint after initial x-rays
e.g., Avascular Necrosis (AVN), Legg-Calve-Perthes Disease
Loose Bodies or Synovial Chondromatosis (38)
(After X-Ray or Ultrasound Completed)
In the setting of joint pain or mechanical symptoms
Infection of Bone, Joint, or Soft Tissue Abscess (39)
- Abnormal x-ray or ultrasound
- Negative x-ray or ultrasound but with a clinical suspicion of infection based on either of the following:
- Signs and symptoms of joint or bone infection such as:
- Pain and swelling
- Decreased range of motion
- Fevers
- Laboratory findings of infection include any of the following:
- Elevated ESR or CRP
- Elevated white blood cell count
- Positive joint aspiration
- Signs and symptoms of joint or bone infection such as:
- Ulcer (diabetic, pressure, ischemic, traumatic) with signs of infection (redness, warmth, swelling, pain, discharge which may range from white to serosanguineous) that is not improving despite treatment and bone, or deep infection is suspected(40)
- Increased suspicion if size or temperature increases, bone is exposed/positive probe-to-bone test, new areas of breakdown, new smell
- Neuropathic foot with friable or discolored granulation tissue, foul odor, non-purulent discharge, and delayed wound healing(40)
Pre-Operative/Procedural Evaluation
Pre-operative evaluation for a planned surgery or procedure
Evaluation of Tumor
When needed for clarification of vascular invasion from tumor after prior imaging.
Post-Operative/Procedural Evaluation
- When imaging, physical examination, or laboratory findings indicate joint infection, delayed or non-healing or other surgical/procedural complications.
- Trendelenburg sign(41) or other indication of muscle or nerve damage after recent hip surgery
Evaluation of Known or Suspected Autoimmune Disease (42,43)
- Further evaluation of an abnormality or non-diagnostic findings on prior imaging
- Initial imaging of a single joint for diagnosis or response to therapy after plain films and appropriate lab tests (e.g., RF, ANA, CRP, ESR)
- To determine change in treatment or when diagnosis is uncertain prior to start of treatment
- Follow-up to determine treatment efficacy of the following:
- Early rheumatoid arthritis
- Advanced rheumatoid arthritis if x-ray and ultrasound are equivocal or noncontributory
e.g., Rheumatoid Arthritis
Known or Suspected Inflammatory Myopathies (44)
- For diagnosis
- For biopsy planning
NOTE: Includes polymyositis, dermatomyositis, immune-mediated necrotizing myopathy, inclusion body myositis
Peripheral Nerve Entrapment (45,46)
- Abnormal electromyogram or nerve conduction study
- Abnormal x-ray or ultrasound
- Clinical suspicion and failed 4 weeks conservative treatment including at least two of the following (active treatment with physical therapy is not required):
- Activity modification
- Rest, ice, or heat
- Splinting or orthotics
- Medication
e.g., Tarsal tunnel, Morton’s neuroma
Foreign Body (47)
Indeterminate x-ray and ultrasound
Painful Acquired or Congenital Flatfoot Deformity (48,49)
Adult
- After X-ray completed
- After failure of active conservative therapy
- Including at least two of the following (active treatment with physical therapy is not required):
- Activity modification
- Rest, ice, or heat
- Splinting or orthotics
- Medication
- Including at least two of the following (active treatment with physical therapy is not required):
Pediatrics (Up to Age 18)
- Painful flatfoot (pes planus) deformity with suspected tarsal coalition, not responsive to non-active conservative care (such as orthotics, rest etc.) (50)
- Slipped Capital Femoral Epiphysis with negative frog leg and AP x-rays of the hips but clinically suspected(51,52)
- Drehmann sign
- Limited internal rotation of the hip
- Consider imaging the asymptomatic contralateral hip with a normal x-ray to detect early SCFE if prophylactic surgery is planned
- Chronic Recurrent Multifocal Osteomyelitis after initial work-up (labs (i.e. CRP/ESR and x-ray)(53,54)
- Whole body bone marrow MRI is more appropriate when multiple joints requested see Evolent_CG_059 for Bone Marrow MRI)
- Acute limp in a child 5 or less years old(55)
- Concern for infection not localized to the hip (initial imaging not required)
- Concern for infection localized to the hip after initial evaluation with ultrasound
- Osteoid Osteoma – MRI not usually done because x-ray and CT more accurate for diagnosis(56)
Rationale
MRI
Magnetic resonance imaging shows the soft tissues and bones. With its multiplanar capabilities, high contrast, and high spatial resolution, it is an accurate diagnostic tool for conditions affecting the joint and adjacent structures.
MRI can positively influence clinicians’ diagnoses and management plans for patients with conditions such as primary bone cancer, fractures, abnormalities in ligaments/tendons/cartilage, septic arthritis, and infection/inflammation.
Special Note
- Plain radiographs must precede MRI evaluation unless otherwise indicated
- Some indications are for MRI, CT, or MR or CT Arthrogram (more than one should not be approved at the same time)
- If an MR Arthrogram fits approvable criteria below, approve as MRI
OVERVIEW
*Conservative Therapy
Musculoskeletal should include a multimodality approach consisting of a combination of active and inactive components.
Inactive components such as rest, ice, heat, modified activities, medical devices, (including crutches, immobilizer, metal braces, orthotics, rigid stabilizer, or splints, etc. and not to include neoprene sleeves), medications, injections (bursal, and/or joint, not including trigger point), and diathermy, can be utilized.
Active modalities may consist of physical therapy, a physician supervised home exercise program**, and/or chiropractic care.
**Home exercise program (HEP)
The following two elements are required to meet guidelines for completion of conservative therapy:
- Information provided on exercise prescription/plan AND
- Follow-up with member with information provided regarding completion of HEP (after suitable 4-week period), or inability to complete HEP due to physical reason- i.e., increased pain, inability to physically perform exercises.
NOTE: Patient inconvenience or noncompliance without explanation does not constitute
“inability to complete” HEP
Contraindication and Preferred Studies
- Contraindications and reasons why a CT/CTA cannot be performed may include: impaired renal function, significant allergy to IV contrast, pregnancy (depending on trimester)