[Acute and chronic instability of the elbow joint].

Successful treatment of elbow instability is aided by fundamental biomechanical understanding. This allows for clinical instability to be traced back to structural injuries, which can be addressed with targeted therapy. Acute instability of the elbow joint after frequent posterolateral dislocations tends to affect the radial ligamentous complex. In addition to simple ligamentous injuries, fractures can also contribute to elbow instability; comminuted fractures of the radial head often correlate with a rupture of the ulnar collateral ligament. Improperly healed acute injuries can result in chronic instability. However, recurrent microtrauma such as that seen in throwing athletes can also lead to changes in joint laxity. Conservative therapy of simple elbow dislocation usually leads to satisfactory results. In isolated cases, chronic lateral instability may result that requires operative stabilization. Recently, chronic posterolateral instability has been seen as the primary underlying pathology in unstable elbows. Chronic medial instability is also a problem for active athletes and may even lead to inability to participate in athletics. Conservative therapy should be the primary course of treatment. Surgical treatment may be indicated if conservative measures fail, if an athlete desires additional treatment, or in cases of high-grade medial instability. In this case, a rehabilitation period of up to one year should be expected.