Anterior thigh pain is related either to the lateral femoral cutaneous nerve (a nerve that enters the thigh around the pelvis and is liable for compression with long surgeries like you had) or from L1-3 originating from the upper lumbar spine. If it is nerve injury from compression (from lying on your belly in a long surgery), then over time, the symptoms should improve.
The posterior thigh pain that radiates down to the foot is from irritation or injury to the L5 or S1 nerve. The nerve needs to be manipulated in a redo decompression and this can cause irritation. Generally, if that is the case, I will order an MRI to make sure the nerve is decompressed and no hematoma (that can cause compression) has formed.