The effect of suture fixation of type I coronoid fractures on the kinematics and stability of the elbow with and without medial collateral ligament repair.

The objective of this study was to determine the effect of suture repair of type 1 coronoid fractures on elbow kinematics in ligamentously intact and medial collateral ligament (MCL)-deficient elbows. Cadaveric testing was performed in stable and MCL-deficient elbows with radial head arthroplasty and with the coronoid intact, with the coronoid fractured, and after suture repair. Ulna versus humerus angulation was measured during active motion. Varus and valgus motion pathways were measured during passive gravity-loaded flexion. With intact ligaments, there was a small increase in valgus angulation after a type 1 fracture that was not corrected with suture fixation. With MCL deficiency, there was no change in kinematics regardless of coronoid status. Type 1 coronoid fractures cause only small changes in elbow kinematics that are not corrected with suture repair. MCL repair, rather than type 1 coronoid fixation, should be considered if the elbow remains unstable after radial head repair or replacement and lateral ligament repair.