Ex vivo biomechanical comparison of four Center of Rotation Angulation Based Leveling Osteotomy fixation methods

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Veterinary orthopedics

Background:

• Center of Rotation Angulation (CORA)-Based Leveling Osteotomy (CBLO) is a surgical technique used to correct angular limb deformities.
• The biomechanical strength of fixation constructs is crucial for successful osteotomy healing.
• Various methods exist to augment CBLO fixation, but their comparative strength requires further investigation.

Purpose of the Study:

• To compare the biomechanical strength of four different fixation constructs for CBLO in an ex vivo canine model.
• To evaluate the yield load and ultimate load of each construct.

Main Methods:

• An ex vivo study utilizing 32 canine tibiae.
• Four fixation groups were tested: plate and pin (Plate), plate with countersink compression screw (HCS), plate with tension band (TB), and plate with HCS and TB (HCSTB).
• Constructs were subjected to distraction loading until failure to measure stiffness, yield load, and ultimate load.

Main Results:

• No significant differences in construct stiffness were observed between the four groups.
• The HCSTB group demonstrated a significantly greater yield load compared to the Plate, HCS, and TB groups.
• The HCSTB group also exhibited a significantly greater ultimate load than the other three fixation methods.

Conclusions:

• Augmenting CBLO fixation with both a tension band (TB) and a countersink compression screw (HCS) results in a stronger construct.
• This combined augmentation strategy provides superior yield and ultimate load capacity compared to using either augmentation alone or a simple plate fixation.
• The findings suggest that HCSTB is a biomechanically superior fixation method for CBLO procedures.