# MRI RIGHT ANKLE – FINAL REPORT

**Clinical information:** Male, 30s. Chronic right ankle pain. Remote inversion sprain. Ankle arthroscopy 2018 with anterior osteophyte resection.

**Technique:** Sagittal STIR, sagittal T1 TSE, axial T1 TSE, axial PD SPAIR, coronal T1 TSE, coronal PD SPAIR. No intravenous contrast. Fat suppression is inhomogeneous in the medial/plantar heel soft tissues on the coronal PD SPAIR, limiting assessment there. No comparison study available.

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## FINDINGS

**Tibiotalar joint – effusion and synovium**
- Moderate tibiotalar joint effusion distending both the anterior and posterior recesses, seen on all fluid‑sensitive sequences.
- Irregular intermediate‑signal tissue fills the anterior recess and extends over the dorsal talar neck, replacing normal fat on T1 and thickening the anterior capsular line on fluid‑sensitive images. In this post‑arthroscopic ankle this is most consistent with anterior capsular scarring/synovitis (soft‑tissue anterior impingement pattern).
- No loose body identified.

**Anterior osseous margins (post‑arthroscopic)**
- The anterior lip of the distal tibia is blunted and mildly irregular with a small residual/recurrent anterior beak, opposed by a small dorsal talar neck prominence (sagittal and axial T1). This is compatible with the prior resection with minor residual/recurrent anterior osseous impingement configuration. No large recurrent osteophyte. No adjacent marrow oedema.

**Lateral gutter and lateral ligament complex**
- Intermediate‑signal soft‑tissue thickening fills the anterolateral gutter between the fibula and lateral talus (axial T1, coronal T1), with fluid in the lateral gutter on coronal PD SPAIR.
- The anterior talofibular ligament is not seen as a discrete taut low‑signal band; instead there is intermediate‑signal thickening at its expected location, consistent with chronic thickened/scarred ATFL following the remote sprain. No acute ligament discontinuity or oedema pattern to suggest recent tear. CFL region shows similar mild thickening; suboptimally assessed in the available planes.
- Lateral malleolar tip marrow shows a subtle linear low‑signal band on sagittal T1, most likely partial‑volume of cortex/ligament attachment; a remote healed small avulsion is not excluded. No acute fracture.
- Syndesmosis: normal tibiofibular relationship, no incisura widening.

**Medial gutter and deltoid ligament**
- Fluid/synovitis in the medial gutter between the medial malleolus and medial talus, with poorly defined superficial deltoid fibres (coronal PD SPAIR) and heterogeneous, mildly thickened deep deltoid on axial T1 – favours chronic deltoid scarring rather than acute injury.

**Subtalar joint and sinus tarsi**
- Increased fluid/oedema signal within the sinus tarsi and tarsal canal with partial loss of the normal fat signal and indistinct interosseous/cervical ligaments on fluid‑sensitive and sagittal T1 sequences (fat better preserved on axial/coronal T1). Appearance is in keeping with sinus tarsi fluid/scarring (sinus tarsi syndrome pattern) following prior inversion injury; a small communicating ganglion is not excluded.
- Mild posterior subtalar joint effusion. Mild subchondral irregularity of the lateral talar process at the posterior facet, without marrow oedema – possible early degenerative change.

**Bones, marrow and cartilage**
- No fracture line. No diffuse marrow oedema in the tibia, fibula, talus or calcaneus.
- Talar dome: a few‑millimetre focal subchondral high‑signal focus in the central/medial talar dome is seen on the sagittal STIR only; no corresponding lesion is confidently identified on T1 or on the axial/coronal fluid‑sensitive sequences, and the talar dome contour is preserved. Findings may represent a tiny subchondral cyst or early focal osteochondral change, but a definite osteochondral lesion is not established.
- Small low‑signal focus with slight contour irregularity at the anterolateral tibial plafond/lateral talar dome margin (coronal T1) – most likely post‑resection contour irregularity or minor subchondral sclerosis; no marrow oedema.
- Dorsal talonavicular/naviculocuneiform margins: mild dorsal marginal high signal with small marginal osteophytes and adjacent soft‑tissue oedema on sagittal STIR; a small focus of increased marrow signal in the dorsal talar head/navicular on axial PD SPAIR – mild dorsal midfoot capsulitis/early degenerative change.
- Calcaneus: normal. No Haglund deformity, no plantar or posterior enthesophyte. Tiny low‑signal dot in the superior calcaneus most likely a vascular channel. No os trigonum.

**Tendons**
- Peroneal tendons: fluid distends the common peroneal sheath in the retromalleolar and inframalleolar groove with mild surrounding soft‑tissue oedema – peroneal tenosynovitis. Tendons are of normal calibre and low signal on T1, normally located, without subluxation. A subtle cleft in the brevis on axial PD SPAIR raises the question of a small longitudinal split but this is not confirmed on other sequences.
- Flexor hallucis longus: fluid in the FHL sheath posterior to the talus and along the posteromedial calcaneus, continuous with the posterior tibiotalar recess – most likely communicating joint fluid, though somewhat more than expected, favouring mild FHL tenosynovitis. Small amount of fluid tracks distally along the medial flexor tendons toward the knot of Henry. Tendon calibre and signal normal.
- Tibialis posterior, FDL: normal.
- Achilles tendon: normal thickness and low signal throughout; a few faint internal intermediate‑signal foci in the distal free tendon on axial T1 are borderline for minimal tendinosis, without partial tear. Kager fat pad clear. Trace fluid in the retrocalcaneal bursa region, not amounting to bursitis.
- Anterior compartment tendons: normal.

**Plantar structures**
- Plantar fascia normal thickness and signal at its calcaneal origin. Spring ligament region unremarkable. Heel fat pad and plantar intrinsic muscles normal. Curvilinear high signal in the medial plantar heel on coronal PD SPAIR reflects the venous plexus and incomplete fat suppression rather than true oedema.

**Soft tissues / muscles**
- Mild nonspecific subcutaneous oedema over the dorsum of the midfoot and around the lateral ankle. No mass, collection or cellulitis. Muscles of normal bulk and signal without fatty atrophy.

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## IMPRESSION

1. **Moderate tibiotalar joint effusion with anterior recess synovitis/capsular scarring and minor residual/recurrent anterior tibial lip and dorsal talar neck osseous prominence** – combined soft‑tissue and mild osseous anterior impingement pattern in this post‑arthroscopic ankle; the most likely correlate for the patient's chronic anterior ankle pain. *(Effusion: high confidence; synovitis/scar: medium; residual osseous impingement: medium.)*

2. **Anterolateral gutter soft‑tissue thickening with chronically thickened/indistinct ATFL** – post‑sprain/post‑arthroscopic capsuloligamentous scarring with anterolateral impingement configuration. No acute ligament tear. *(Medium confidence.)*

3. **Sinus tarsi fluid/scarring with partial fat replacement and mild posterior subtalar effusion** – sinus tarsi syndrome pattern; mild lateral talar process subchondral irregularity suggests early subtalar degenerative change. *(Medium confidence.)*

4. **Peroneal tenosynovitis** without definite tendon tear or subluxation; a subtle peroneus brevis split is questioned on one sequence but not confirmed. *(Tenosynovitis: medium‑high; split tear: low.)*

5. **Fluid in the FHL sheath extending distally toward the knot of Henry**, most likely communicating with the joint effusion with possible mild FHL tenosynovitis. *(Medium confidence.)*

6. **Medial gutter synovitis with chronic deltoid (superficial and deep) scarring**; no acute deltoid tear. *(Medium‑low confidence.)*

7. **Questionable tiny (few‑mm) subchondral focus in the central/medial talar dome**, seen on sagittal STIR only and not confirmed on other sequences; no definite osteochondral lesion. If clinically relevant, could be re‑evaluated with dedicated high‑resolution cartilage‑sensitive sequences or follow‑up. *(Low‑medium confidence.)*

8. **Mild dorsal talonavicular/naviculocuneiform capsulitis with marginal osteophytes and minimal marginal marrow signal** – early degenerative/impingement change. *(Low‑medium confidence.)*

9. No fracture, no significant bone marrow oedema, no tendon rupture, no loose body. Syndesmosis, Achilles tendon (at most borderline distal tendinosis), plantar fascia and spring ligament are intact. *(High confidence.)*