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Internal Derangement of the Knee N046

Document
Last amended 
26 November 2015

Current RMA Instruments:

Reasonable Hypothesis SOP
51 of 2010
Balance of Probabilities SOP
52 of 2010
Changes from previous Instruments:

SOP Bulletin 144

 ICD Coding:
  • ICD-9-CM Codes: 717.0-717.5,717.8,717.9
  • ICD-10-AM code M23.2, M23.5, M23.8 or M23.9
Brief description

This is a chronic condition involving a torn knee meniscus or a damaged knee ligament (or both).

Confirming the diagnosis

Acute knee injuries are likely to be covered by the SOPs for sprain and strain or acute meniscal tear of the knee.  For this diagnosis evidence of chronicity (longer term problems) is required.  It is possible for the diagnosis to be made on clinical grounds but it is preferrable to have arthroscopic, MRI or CT scan evidence.

The relevant medical specialist is an orthopaedic surgeon.

Additional diagnoses covered by the SOP

Chronic symptomatic tear of:

  • Cruciate ligament (anterior or posterior)
  • Collateral ligament (medial or lateral)
  • Capsular ligament
  • Meniscus
Conditions excluded from the SOP
  • Acute articular cartilage tear* of the knee
  • Acute meniscal tear of the knee*
  • Acute sprain of the knee* - sprain and strain SOP
  • Chondral defect of the knee - acute articular cartilage tear or osteoarthritis SOPs
  • Chondromalacia patellae*
  • Congenital discoid meniscus#
  • Cyst of a meniscus#
  • Degenerative tear of a meniscus, ICD code 715 (osteoarthritis), N.I.F., or 717.5 (non-SOP)
  • Grade 1 or grade 2 meniscal degeneration on MRI scan (not a disease)
  • Loose body in the knee joint# - may relate to chondral defect
  • Osteoarthritis* of the knee
  • Osteochondritis dissecans#
  • Recurrent dislocation of the knee* - joint instability SOP
  • Recurrent subluxation of the knee* - joint instability SOP

* another SOP applies  - the SOP has the same name unless otherwise specified

# non-SOP condition

Clinical onset

The diagnosis can't be confirmed until there is evidence of chronicity, but the clinical onset can be retrospectively assessed back to the date of an initiating injury.  If there was no discrete injury event then clincial onset can be dated to the start of relevant persisting knee symptoms.

Clinical worsening

Clinical worsening could result from further injury, causing additional meniscus or ligament pathology or rerupture of a repaired knee ligament.