Complex regional pain syndrome following Cedell fracture

Case contributed by Dr Yuan Ling

Presentation

Fall onto left ankle.

Patient Data

Age: 40 years
Gender: Male
X-ray

Initial x-ray left ankle and foot.

Frontal: comminuted fracture of the posteromedial talar tubercle (medial tubercle of the posterior talar process).

Oblique: Small bony fragments at adjacent to the tip of the lateral malleolus reflect injury of the lateral ankle ligaments.

Lateral: cortical flake of bone at dorsal talar head reflects avulsion of the dorsal talonavicular ligament.

CT

CT left ankle for further evaluation.

Improved depiction of the intra-articular, comminuted, Cedell fracture.

Fragments at the tip of the lateral malleolus likely due to avulsion by CFL and inferior peroneal retinaculum.

Proximal avulsion of the dorsal talonavicular ligament should prompt suspicion of midtarsal (Chopart) sprain. No fracture of the anterior calcaneal process, nor obvious fat stranding around the bifurcate ligament. Tiny os peroneum; no appreciable ligamentocapsular injury of the calcaneocuboid joint.

Small fracture fragments vs chondrocalcinosis in the posterior subtalar joint.

X-ray

4 months after injury, disproportionate pain and swelling.

Small bone fragments at the aforementioned sites of fracture, with small loose body in the posterior joint recess.

Generalized osteopenia, particularly subchondral/peri-articular.
Surrounding soft tissue edema is non-specific.
Disuse osteopenia, or other cause??

CT

4 months after injury, disproportionate pain and swelling.

Bones are diffusely demineralized, particularly of the subchondral bone in the midfoot (peri-articular osteopenia). Joint spaces are preserved and congruent. Cortex appears thinned; no acute or stress fracture. No osseous destruction to suggest osteomyelitis.

MRI

4 months after injury, persistent pain and swelling.

Widespread patchy marrow hyperintensity with a subchondral predilection. No fracture.
Small non-specific ankle and posterior subtalar joints. All ligaments intact.
Non-specific fluid in the peroneal tendon sheath. All tendons intact.
Generalized subcutaneous edema; no focal collection/abscess.
Minor non-specific edema signal in muscles, reactive/sympathetic. No fatty atrophy (denervation unlikely).
 

Nuclear medicine

6 months after injury, persistent pain and skin changes.

Tc-99m MDP limited bone scan with SPECT/CT.

Early images: mildly increased blood flow and blood pool to the left foot, with foci of more markedly increased blood pool in the hindfoot and medial midfoot. 

Delayed images: markedly increased osteoblastic activity adjacent to the posterior subtalar joint, adjacent to the articulation between the medial and middle cuneiform bones, and adjacent to the 1st TMTJ. 
Moderately increased osteoblastic activity adjacent to the 1st MTPJ, and mildly increased periarticular osteoblastic activity elsewhere in the left foot. 

Conclusion: Findings are suggestive of reflex sympathetic dystrophy/complex regional pain syndrome of the left foot, with superimposed arthropathy involving the posterior subtalar, intercuneiform and first TMT joints. 

Case Discussion

Cedell fractures are rare. Complications included malunion, non-union, AVN, and early OA.

Disproportionate pain, swelling, vasomotor instability, and trophic skin changes raise the suspicion of post-traumatic reflex sympathetic dystrophy (complex regional pain syndrome, type 1). Findings relate to hyperemia (increased blood flow and blood pool on bone scan), and peri-articular osteopenia with preservation of joint space.

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Case information

rID: 69567
Published: 17th Jul 2019
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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