**MRI RIGHT ANKLE**

**CLINICAL HISTORY:** Male in his 30s, chronic right ankle pain, remote history of an ankle sprain, previous ankle arthroscopy (2018, osteophyte resection).

**FINDINGS:**

**Bones and Articular Cartilage:**
There is a focal osteochondral lesion (OCL) at the medial aspect of the talar dome, characterized by a hyperintense subchondral cyst, surrounding reactive bone marrow edema, and overlying articular cartilage thinning and irregularity. 
At the anterior tibiotalar joint, there are prominent, beak-like recurrent/residual osteophytes at the anterior margin of the tibial plafond and the dorsal aspect of the talar neck. There is marked "kissing" bone marrow edema directly adjacent to these osteophytes. The anterior margin of the distal tibia demonstrates irregularity and flattening, consistent with the patient's prior osteophyte resection. 
There is mild reactive subchondral bone marrow edema near the posterior facet of the subtalar joint. A prominent elongated posterior process of the talus (Stieda process) is present, with no obvious os trigonum or fracture line. Mild dorsal osteophytosis is noted at the talonavicular joint. The remainder of the regional bone marrow signal is normal.

**Joints:**
There is a moderate tibiotalar joint effusion extending into the medial and lateral gutters. A small to moderate subtalar joint effusion is also present. 

**Ligaments:**
The anterior talofibular ligament (ATFL) is markedly thickened, nodular, and demonstrates irregular, heterogeneous signal, lacking its normal thin, taut appearance. This is classic for a chronic, scarred tear. The calcaneofibular ligament (CFL) region also demonstrates soft tissue thickening and ill-defined signal, consistent with chronic post-traumatic scarring. The superficial and deep fibers of the medial deltoid ligament complex are mildly thickened, suggestive of chronic stress or a low-grade chronic sprain. The posterior talofibular ligament (PTFL) and tibiofibular syndesmotic ligaments are intact.

**Tendons:**
There is a prominent amount of fluid distending the tibialis posterior tendon sheath, consistent with marked tenosynovitis; the tendon itself is continuous but may be mildly tendinopathic. Fluid is also noted distending the common peroneal tendon sheath on sagittal imaging, consistent with tenosynovitis. A small amount of fluid in the flexor hallucis longus (FHL) tendon sheath likely represents physiologic communication with the joint effusion. The Achilles tendon and anterior extensor tendons demonstrate normal course, caliber, and signal intensity. 

**Soft Tissues:**
There is intermediate-to-low T1 signal soft tissue thickening in the anterior joint space, interposed between the anterior tibial and talar osteophytes. This represents capsular scarring and synovial hypertrophy, consistent with an anterior soft tissue impingement component. 
Within the sinus tarsi, there is hyperintense STIR signal replacing the normally suppressed fat, though T1 fat signal is preserved, suggestive of sinus tarsi syndrome. Diffuse subcutaneous edema is present surrounding the ankle, most prominent anterolaterally and medially. The plantar fascia is of normal thickness and signal intensity at its calcaneal origin.

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**IMPRESSION:**

1. **Recurrent Anterior Ankle Impingement Syndrome:** Prominent recurrent/residual bony osteophytes at the anterior tibial plafond and dorsal talar neck with active "kissing" bone marrow edema. This is accompanied by anterior capsular scarring/synovial hypertrophy contributing to soft tissue impingement. *(Confidence: High)*
2. **Osteochondral Lesion (OCL):** Focal osteochondral lesion of the medial talar dome with a subchondral cyst, reactive bone marrow edema, and an overlying chondral defect. *(Confidence: High)*
3. **Chronic Lateral Ligamentous Injury:** Markedly thickened and scarred anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL), consistent with the patient's remote history of an ankle sprain. *(Confidence: High)*
4. **Tenosynovitis:** Marked tibialis posterior tenosynovitis and mild peroneal tenosynovitis. *(Confidence: High)*
5. **Sinus Tarsi Syndrome:** Edema within the sinus tarsi, likely a sequela of the patient's chronic lateral ligamentous instability/remote sprain. *(Confidence: High)*
6. **Joint Effusions:** Moderate tibiotalar and small-to-moderate subtalar joint effusions, with mild reactive subchondral edema at the posterior subtalar facet. *(Confidence: High)*
7. **Deltoid Ligament:** Mild chronic thickening of the deltoid ligament complex, likely representing chronic stress or low-grade sprain. *(Confidence: Medium)*