The smaller incisions for the mini-incision joint replacements definitely mean it's harder for the surgeon to see all the anatomy. They do use a special X-ray called fluoroscopy that allows them to see inside the joint. It's not quite the same as the standard open method.
The nerves can get cut when the surgeon replaces the hip from the front or anterior approach. The lateral femoral cutaneous nerve is one cut most often. Numbness in the thigh is the most common complaint. Itching, burning, and tingling are also possible. The symptoms can be mild to severe.
The problem usually goes away gradually over time. It can take up to a full year or longer. Occasionally there is permanent nerve damage.