What's the biggest drawback to the newer minimally-invasive joint replacements?

Many possible disadvantages have been reported. Most have to do with the small visual field. Some relate to learning a new method. Surgeons often have better results the more times they do the operation. Early attempts may have poorer results or more complications.

Sometimes one factor leads to another and another. For example, it might take longer to do a surgery that's new to the surgeon. Longer operating time means longer exposure to anesthesia. Longer surgery time also leads to higher risk for blood clot or infection.

Overall not being able to see clearly inside and around the joint is the surgeon's biggest drawback. Finding the anatomy to guide each incision makes a difference. Implant placement and function depends on finding the landmarks and vital structures.