Stem damage during implantation of modular hip prostheses

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Medical device engineering

Background:

• Modular hip prostheses are widely used in joint replacement surgery.
• Specialized surgical instruments, such as stem holders, are essential for implanting these prostheses.
• Ensuring proper coupling between the prosthesis and instrumentation is critical to prevent damage.

Purpose of the Study:

• To evaluate potential stem damage induced by modular hip prosthesis stem holders.
• To identify specific stem holder design features that minimize such damage.
• To analyze the impact of simulated surgical handling on stem-holder interactions.

Main Methods:

• Investigation of two distinct stem holder connector designs for a specific modular hip prosthesis system (AnCAFit).
• Simulated surgical handling to mimic in-vivo use.
• Surface inspection of the stem cavity to identify and quantify damage caused by the stem holders.

Main Results:

• Both investigated stem holder designs induced surface damage on the prosthesis stem cavity.
• A purportedly improved stem holder design resulted in significantly greater damage compared to the other design.
• Observed scars on the stem cavity surface indicate potential for fretting corrosion and debris generation during the implant's service life.

Conclusions:

• Stem holders for modular hip prostheses can cause detrimental surface damage to the implant stem.
• The design of the stem holder connector plays a crucial role in the extent of damage.
• Damage induced by stem holders may compromise the long-term performance of hip implants by initiating fretting debris production.