Patient-specific acetabular alignment guides

An acetabular system comprising:

• a patient specific acetabular alignment guide including a bone engagement surface configured and shaped to be conforming and complementary to an acetabular and periacetabular area of an acetabulum of a specific patient in accordance with a three-dimensional model of the acetabulum of the specific patient and based on a pre-operative plan, the acetabular alignment guide including a plurality of guiding formations extending therethrough for guiding a plurality of alignment pins in a periacetabular area of a patient;
• an acetabular instrument including a handle, a shaft and an acetabular coupler;
• and
• a first alignment adapter removably coupled to the shaft of the acetabular instrument, the first alignment adapter including a plurality of apertures configured to correspond to the guiding formations of the acetabular alignment guide, such that the alignment pins can pass through the apertures of the alignment adapter after the acetabular alignment guide is removed without removing the alignment pins from the patient.