It falls under combination products per the definitions below:
Combination products are products that combine drugs, devices and or biological products.
1. A product comprised of two or more regulated components
2. Two or more separate products packaged together in a single package
3. A drug, device, or biological product packaged separately that according to its investigation plan or proposed labeling is intended for use only with an approved individually specified drug
https://www.fda.gov/CombinationProducts/AboutCombinationProducts/ucm118332.htm
The primary mode of action is defined as “the single mode of action of a combination product that provides the most important therapeutic action of the combination product.”
https://www.mddionline.com/combination-products-primary-mode-action-refined

Its primary mode of action is intended to replace a defective bone to support the hip.
Class II device
The claim would be the implant will treat infection in a single procedure.
Pre-clinical Research
The tests should include cytotoxicity, genotoxicity, irritation, system Tox, hemocompatability, implantation, Toxikokinetics
IDE is required for significant risk device study:
It is considered significant risk if the implant poses a serious risk to health, safety or welfare and it sustains life. Being that that hip stem is not supporting life an IDE is not required.
https://www.fda.gov/downloads/RegulatoryInformation/Guidances/UCM126418.pdf