Mueller-Weiss syndrome (classification)

Mueller Weiss syndrome refers to a spontaneous adult onset osteonecrosis of the tarsal navicular. This syndrome is multifactorial and related to chronic loading on a suboptimally ossified navicular bone which is susceptible to central osteonecrosis due to its centripetal blood supply. It is distinct from Köhler disease, the osteochondrosis of the tarsal navicular bone that occurs in children.

Radiographic features

Classification

• mild
  • stage 1: normal radiographs but subtle subtalar varus deformity may be present because of lateral displacement of the talar head which can cause an overlap with the anterior calcaneal process
• moderate
  • stage 2: dorsolateral subluxation of the talus resulting in cavovarus and dorsal angulation of the Meary-Tomeno line
  • stage 3: compression or splitting of the navicular resulting in a lowered longitudinal arch and neutral Meary-Tomeno line 
• severe
  • stage 4: compression of the navicular leading to hindfoot equinization and loss of the longitudinal arch and plantar angulation of the Meary-Tomeno line
  • stage 5: talocuneiform neoarticulation and extrusion of a fragmented navicular also known as listhesis navicularis