Relationship Between the Lateral Collateral Ligament of the Elbow and the Kocher Approach: A Cadaver Study

Abstract

Purpose: The lateral ulnar collateral ligament (LUCL) is considered to be the portion of the lateral collateral ligament playing the most important stabilizing role. Iatrogenic forms of posterolateral rotatory instability have been described. The Kocher approach is a popular approach to the lateral side of the elbow. The aim of this study was to describe the relationship between the LUCL and the Kocher interval.

Methods: The Kocher interval was identified and marked in 20 cadavers. The LUCL was identified and the distance between the LUCL insertion on the tubercle of the cresta supinatoris and the Kocher interval was calculated (TK distance). This distance was considered 0 if the Kocher interval was directly above the tubercle, as a positive value if it was anterior to the tubercle, and as a negative value if it was posterior. Finally, the Kocher interval was sharply opened, and elbow stability was tested using the posterolateral rotatory drawer test.

Results: A discrete LUCL was identified in 16 specimens. The mean TK distance was -2.3 ± 4.4 mm (range, -11 to +10). The median TK distance was -3 mm. The posterolateral rotatory drawer test was positive for subluxation after the sharp incision of the Kocher interval in 15 specimens. The median TK distance was significantly higher in the stable group (+2 mm) than in the unstable group (-3 mm).

Conclusions: The LUCL often lies beneath the Kocher interval and is at risk during the Kocher approach.

Clinical relevance: Iatrogenic forms of posterolateral rotatory instability could result from this approach.

Keywords: Cadaver; Kocher approach; iatrogenic elbow instability; lateral ulnar collateral ligament; posterolateral rotatory instability.