This is a randomized controlled trial (RCT) to evaluate the introduction of a 3D printed model into the pre and intra-operative planning for arthroscopic femoroacetabular impingement (FAI) surgery. The RCT will look to place patients into one of two treatment groups: 1) conventional preoperative imaging (X-ray, CT, and MRI) only and 2) those that have had a 3D printed model created in addition to the conventional imaging.

In this study, we investigate the use of 3D models during pre and intra-operative planning could improve the success of hip arthroscopy and reduce the incidence of revision cases. By adding an adjunct to the common suite of pre-operative imaging modalities (X-ray, MRI and CT), we can change the surgeon's understanding of each patient's individual morphology with a tactile physical model. This study will compare the success of hip arthroscopy in patients with or without 3D printed models (in addition to traditional pre-operative imaging).

This will be a single-center, blinded observer, randomized controlled trial of 80 patients performed at the Halifax Infirmary, Queen Elizabeth II Health Sciences Center in Halifax, Nova Scotia. Patients with cam-type FAI involved in the study will be approached by the surgeon, Dr. Ivan Wong, or a delegate regarding the study during a pre-operative visit. Following a detailed discussion of the risks/benefits/alternatives of this study, the patient will be provided with a copy of the informed consent to review, if they demonstrate an interest in the study. If the patient wishes to be enrolled in the study, the research team will obtain patient consent for the study according to the Division of Orthopaedic Surgery and Nova Scotia Health Authority (NSHA) institutional protocols.

In the pre-operative period, there will be no additional time requirements for the participant, except for the informed consent process for the study. Routine X-ray radiographs, as well as a pre-operative MRI and CT scan, will be obtained for all subjects undergoing FAI surgery. The participants will not be exposed to any additional radiation. Subjects will complete a structured clinical examination conducted by a sports medicine fellowship-trained orthopaedic consultant. The patient will also complete pre-operative questionnaires.

Patients that have consented to the study will be randomized into two groups with a 50% chance of being in either group. Randomization will be done with a computer random number generator. Both groups will undergo routine pre-operative imaging but one group will also have a 3D print made from the 3D CT reconstruction. All patient groups will undergo hip arthroscopy for the treatment of their FAI.

Inclusion Criteria:

• Radiological proven diagnosis of cam-type femoroacetabular impingement (FAI)

Exclusion Criteria:

• Patients with advanced arthritis (Tonnis Grade III or Kellgren-Lawrence Grade III or IV or evidence of less than 2 mm of joint space, as determined by conventional radiographs.)
• Patients with 1cm2 (or greater) of cartilage delamination in the hip
• Patients with type III or IV heterotopic ossification
• Patients with avascular necrosis
• Patients who are unable to provide informed consent
• Patients who are undergoing revision hip arthroscopy
• Patients who are pregnant
• Patients who have the presence of local or systemic infection
• Patients with an inability to cooperate with and/or comprehend post-operative instructions
• Patients with nonvascular surgical sites (MRI proven)
• Patients with cancer

Individual participant data will not be shared with other researchers.

Participants will be blinded/masked to the treatment (if they do or don't receive a 3D printed model of their hip) they receive until the end of the study. Patients will still be aware of the details of their surgical treatment.