Answer for BIR CoW 01 Apr 2018
Talus & Navicular Avascular Necrosis
Findings
Impacted fracture neck of talus. Talar dome & body sclerosis with articular cortical depressed fracture in the dome. Dislocation of subtalar joint with anterior translation. Diffuse sclerosis with collapse & fragmentation of navicular bone. Secondary osteoarthritic changes in talo-navicular & calcaneo-cuboid joint. Ankle joint effusion. DIAGNOSIS : Avascular Necrosis Of Talus & Navicular Bone with secondary osteoarthritis.
Discussion
Avascular necrosis (AVN) is a generic term referring to the ischaemic death of the constituents of bone. AVN has a wide variety of causes and can affect nearly any bone in the body. MRI is the most sensitive modality and demonstrates changes well before plain films changes are visible. -diffuse oedema: oedema is not an early sign; instead, studies show that oedema occurs in advanced stages and is directly correlated with pain -reactive interface line is a focal serpentine low signal line with -fatty centre (most common appearance and first sign on MRI) -double line sign: serpiginous peripheral/outer dark (sclerosis) and inner bright (granulation tissue) on T2WI is diagnostic -rim sign: osteochondral fragmentation: -secondary degenerative change AVN of the talus occurs with an interruption in any part of the vascular network, including arteries, capillaries, sinusoids, and veins. Severe necrosis along with resorption around necrotic bone leads to the collapse of articular surfaces. In severe AVN, the talar dome is a typical location for articular collapse. However, collapse may also occur at the inferior articular surface of the talus (subtalar joint). T2 weighted images display a typical double line sign which consisting of a hypointense outer line (sclerosis and fibrosis) and a hyperintense inner line (granulation tissue). Osteonecrosis of Navicular Bone – -Köhler disease is an eponymous term referring to childhood-onset osteonecrosis of the navicular bone in the foot. It typically presents in the paediatric population (4-6 years of age) and there is a recognised male predilection. navicular may appear wafer-like (thinned) and fragmented, demonstrates patchy sclerosis and is often associated with soft tissue swelling -Mueller Weiss syndrome refers to spontaneous multifactorial adult onset osteonecrosis of the tarsal navicular. It occurs in adults between 40 and 60 years of age and is more common in females. Patients present with mid- and hindfoot pain and pes planovarus. There may be acomma-shaped deformity due to collapse of the lateral part of the bone with medial or dorsal protrusion of a portion of the bone or the entire navicular bone. MRI shows edema on STIR images The disease may be bilateral or asymmetric and associated with pathologic fractures. references - Yochum & Rowe's Essentials of Skeletal Radiology Avascular necrosis of Talus - A Pictorial Essay (Pearce et al)
Findings
Impacted fracture neck of talus. Talar dome & body sclerosis with articular cortical depressed fracture in the dome. Dislocation of subtalar joint with anterior translation. Diffuse sclerosis with collapse & fragmentation of navicular bone. Secondary osteoarthritic changes in talo-navicular & calcaneo-cuboid joint. Ankle joint effusion. DIAGNOSIS : Avascular Necrosis Of Talus & Navicular Bone with secondary osteoarthritis.
Discussion
Avascular necrosis (AVN) is a generic term referring to the ischaemic death of the constituents of bone. AVN has a wide variety of causes and can affect nearly any bone in the body. MRI is the most sensitive modality and demonstrates changes well before plain films changes are visible. -diffuse oedema: oedema is not an early sign; instead, studies show that oedema occurs in advanced stages and is directly correlated with pain -reactive interface line is a focal serpentine low signal line with -fatty centre (most common appearance and first sign on MRI) -double line sign: serpiginous peripheral/outer dark (sclerosis) and inner bright (granulation tissue) on T2WI is diagnostic -rim sign: osteochondral fragmentation: -secondary degenerative change AVN of the talus occurs with an interruption in any part of the vascular network, including arteries, capillaries, sinusoids, and veins. Severe necrosis along with resorption around necrotic bone leads to the collapse of articular surfaces. In severe AVN, the talar dome is a typical location for articular collapse. However, collapse may also occur at the inferior articular surface of the talus (subtalar joint). T2 weighted images display a typical double line sign which consisting of a hypointense outer line (sclerosis and fibrosis) and a hyperintense inner line (granulation tissue). Osteonecrosis of Navicular Bone – -Köhler disease is an eponymous term referring to childhood-onset osteonecrosis of the navicular bone in the foot. It typically presents in the paediatric population (4-6 years of age) and there is a recognised male predilection. navicular may appear wafer-like (thinned) and fragmented, demonstrates patchy sclerosis and is often associated with soft tissue swelling -Mueller Weiss syndrome refers to spontaneous multifactorial adult onset osteonecrosis of the tarsal navicular. It occurs in adults between 40 and 60 years of age and is more common in females. Patients present with mid- and hindfoot pain and pes planovarus. There may be acomma-shaped deformity due to collapse of the lateral part of the bone with medial or dorsal protrusion of a portion of the bone or the entire navicular bone. MRI shows edema on STIR images The disease may be bilateral or asymmetric and associated with pathologic fractures. references - Yochum & Rowe's Essentials of Skeletal Radiology Avascular necrosis of Talus - A Pictorial Essay (Pearce et al)
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!