Is Lateral Onset Cross Pin Technique Strong Enough? A Biomechanical Study.

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Fracture Management

Background:

• Supracondylar humeral fractures are common injuries requiring stable fixation.
• Various pinning techniques exist, each with potential biomechanical advantages and disadvantages.

Purpose of the Study:

• To biomechanically compare the lateral onset cross-pinning (LXP) technique with three other pin configurations for supracondylar humeral fractures.
• To evaluate the stability of different pinning methods under varus, valgus, and flexion bending forces.

Main Methods:

• Biomechanical testing was conducted on 52 synthetic humeri using a Shimadzu Autograph measuring machine.
• Four pin configurations were tested: crossed pins (XP), 2 lateral pins (2LP), 3 lateral pins (3LP), and LXP.
• Each configuration underwent varus bending, valgus bending, and flexion bending tests, with displacement and load data recorded.

Main Results:

• The 2LP group exhibited significantly lower varus displacement and flexion load values compared to XP, 3LP, and LXP groups (p<0.05).
• No significant differences in valgus stability were observed between the groups (p>0.05).

Conclusions:

• The LXP technique demonstrates comparable biomechanical stability to the traditional XP technique.
• The 2LP technique appears less stable in varus and flexion compared to other tested methods.
• Findings are relevant for surgeons selecting fixation strategies, particularly for complex distal humerus fractures.