| Title : Case 104 |
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Age / Sex : 22 / M Age/Sex: 22/M Diagnosis: peroneal longus tendon dislocation DiscussionFindings: T2-weighted axial images show periosteal stripping and SPR insufficiency (Type I SPR injury) with minimal tendon subluxation at time of exam. SPR is elevated from its normal attachment to the posterolateral margin of the fibula, and irregular thickened. The periosteum is partially stripped and thickened, forming a false pouch. On T2- weighted axial images with ankle dorsiflexion, the peroneal bevis tendon is seen posterior to the lateral malleolus and the peroneal longus tendon is subluxed lateral to the fibula. The SPR is laterally displaced from its normal attachment at the lateral margin of the lateral malleolus, remaining attached to the fibular periosteum, which is stripped and elevated by the dislocated tendon. The stripped periosteum forms a false pouch into which the peroneus longus is displaced. Op finding: - type 1 injury of distal SPR - convex contour of peroneal or retromalleolar groove - grossly o.k. of peroneus longus tendon Diagnosis: Subluxation of the peroneus longus tendon with Type I injury of the superior peroneal retinaculum. Discussion: - Superior peroneal retinaculum (SPR): ü primary constraint to peroneal tendon subluxation ü formed as a confluence of superficial fascia of the leg, and common peroneal tendon sheath, and periosteum of distal fibula (about 2 cm proximal to fibula tip) ü runs posteriorly to blend with the Achilles tendon sheath ü synovial sheath passes behind the distal fibula (retromalleolar sulcus) ü the depth of the sulcus may be related to propensity for peroneal subluxation - Injury mechanism ü Injury of SPR occurs with peroneal dislocation through forceful ankle dorsiflexion and concomitant reflex peroneal muscle contraction. ü Subluxation of the peroneal tendons may be provoked by having the patient dorsiflex the foot from a position of dorsiflexion and eversion. ü Oden classification of SPR injury: Type 1: detached from the lateral malleolus together with stripping and elevation of the periosteum to which it is attached, forming a false pouch Type 2: torn near the lateral fibular margin Type 3: associated avulsion fracture(+) Type 4: a tear of the posterior portion of the SPR - Ultrasound: effective in real-time demonstration of recurrent peroneal subluxation or dislocation. - MRI : a complete assessment of the structures at risk, associated pathology, and diagnostic mimics. ü The diagnosis of dislocation of the peroneal tendons is made when either or both tendons are not identified in their normal anatomic positions posterior to the lateral malleolus and the diagnosis of complete tendon rupture and retraction is excluded. ü With peroneal tendon dislocation, the periosteum is stripped and elevated together with the attached SPR, forming a false pouch lateral to the fibular margin. The tendons may reduce, but the SPR remains incompetent, allowing recurrent subluxation and/or dislocation. The resultant abnormal stress leads to tendon. Identification of periosteal stripping and an abnormal pouch is particularly important in patients with recurrent episodes of tendon subluxation, who may have normally positioned tendons at the time of imaging. References: 1. Rosenberg ZS, Bencardino J, Astion D, Schweitzer ME, Rokito A, and Sheskier S. MRI Features of Chronic Injuries of the 2. Wang XT, Rosenberg ZS, Mechlin MB, Schweitzer ME. Normal Variants and Diseases of the Peroneal Tendons and |
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| Name | Institution |
| Total Applicants (8) | |
| Correct Answer (5) | |
| 김성준: 영동세브란스병원 | |
| 박상현: 순천향대학천안병원 | |
| 박소영: 분당서울대병원 | |
| 이승훈: 서울보훈병원 | |
| 이재혁: 경북대학교병원 | |
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