OrthoNet

Dislocations of the Proximal Tib/Fib Joint

Reference: Ogden, JBJS 56A, 145-154

Main Message

- Acute dislocations are treated with closed reduction usually, and are usually stable. If unstable, open reduction and ligamentous repair +/- K-wiring is recommended. Arthrodesis is not recommended because it screws up ankle motion. If peroneal nerve symptoms arise, consider resection of the fibular head.

Points of Interest

- Classified into subluxation and 3 types of dislocation - superior, anterolateral, posteromedial.
- Often associated with severe trauma, and often missed
- The joint is supported anteriorly by thickened capsule, which is probably extension from biceps tendon.
- Posteriorly, there is a thick capsule reinforced by popliteus
- The fibular collateral ligament provides the most proximal support of the joint.

Acute dislocations - require muscle relaxation, then flexion of the knee to relax the ligament, followed by a firm push in the direction required. Once reduced, they are usually stable. They generally speaking do not require immobilization, and non-weightbearing is recommended for 2 weeks.

In the rare case where closed reduction is unsuccessful, it is debatable what to do. The authors in Rockwood and Green suggest that leaving them alone with a recurrently subluxating joint is okay, and if they run into problems down the road you can offer further treatment - fixation, arthrodesis, resection.

If you need to treat someone with recurrent instability and PAIN, open reduction and internal fixation with K-wires that are removed at 6 weeks is suggested, or simple resection if peroneal nerve symptoms occur. Arthrodesis is not advocated because of long-term discomfort in the ankle.

Thoughts….