Hip implants come in different sizes. Currently, surgeons predict the implant size that will be needed using an analogue method whereby photos of the implant sizes are overlaid on the x-rays. In this study, we propose to use a digital, computerized method of templating which we expect will be more accurate than the overlay method.

Inclusion Criteria:

• Patients booked for primary total hip arthroplasty with non-cemented prosthesis.
• No previous surgery/fractures to acetabulum or femur or hip.
• No gross bony abnormality except for osteoarthritis and avascular necrosis.

Exclusion Criteria:

• Cancer or tumor suspected, morbid obesity, revision, previous acetabular/femur/hip surgery, gross bony deformity, calibration bar not completely pictured on radiograph, unsuccessful surgery fracture/cancer/cemented prosthesis used.

Patients booked for primary total hip arthroplasty with non-cemented prosthesis