Custom total hip replacement or patient-specific hip replacement, is a newer, more advanced technology in total hip arthroplasty that uses an individualized hip implant for the replacement of the damaged or injured components of the hip joint. The hip implant is an artificial device used to restore the natural anatomy of the hip joint and improve or restore range of motion.
Custom total hip replacement requires a pre-operative CT scan of the hip joint. Using computer software, a virtual 3D model of the patient’s bone anatomy is generated to help the surgeon achieve greater accuracy in positioning the femoral and the acetabular components of the hip implant. The implant matches the size and orientation of the patient’s natural hip joint.
Anatomy of the Hip Joint
The hip is a ball-and-socket joint made up of the head of the thigh bone or femur, that acts as the ball, and the rounded socket of the hip bone or acetabulum. The neck of the femur is the region just below the ball of the hip joint.
Components of the Patient-Specific Hip Implant
The hip implant includes a femoral component with a patient-specific neck, an acetabular cup, and a biocompatible plastic liner. The femoral head can be made of either ceramic or cobalt chrome.
The custom implant is designed such that its shape matches the patient’s bone defect/bone geometry and can adapt to the human body.
Indications for Custom Hip Replacement
Custom hip replacement is recommended for the treatment of the following:
- Large bone defects
- Leg-length discrepancy
- Severe hip joint deformation
- Pelvic discontinuity
- Complications related to existing implants
Pre-Surgical Preparation for Custom Hip Replacement
A few weeks before surgery, your surgeon will order medical imaging tests which include a computed tomography (CT) scan in three positions: standing, seated and step-up (one leg raised and the other straight). Your pelvic - including hip bone and thigh bone - measurements are taken. This helps design the femoral and acetabular components of the implant specific to the individual patient.
After the CT scan images are available, a special tool called a jig is used by your surgeon to develop 3D bone implants. The jigs are a set of disposable patient-specific equipment that are used to assist in implant positioning.
Thus, an optimal implant position and an accurate length of the bone to be incised (cut) will be recorded. This will improve the precision of the custom-fitted total hip arthroplasty procedure.
Procedure: Custom Hip Replacement
You will be administered general anesthesia. During the procedure, a surgical cut is made over the hip to expose the hip joint, and the femur is dislocated from the acetabulum.
- The surface of the femur is prepared by removing the arthritic bone and any soft tissue remnants using special instruments to create space to accommodate the femoral component of the implant.
- Similarly, the surface of the acetabular socket is cleaned, and the damaged or arthritic bone removed.
- Then the femoral head/neck component and acetabular component of the implant are placed into their respective grooves assisted by fixation screws, jigs, and medical imaging. The use of bone cement may be avoided.
- The incision is closed.
Advantages of Custom Total Hip Replacement
The customhip implant offers numerous benefits, including:
- Adapts to the natural bone defect
- Improves hip alignment and joint movements
- Improves stability of the hip joint
- Maximizes the performance of the implant bearing
- Improves surgical accuracy
- Reduces the surgical time
- Improves survival of knee and hip implants
- Minimizes the need for revision surgery
Risks Associated with Custom Hip Replacement
Customized hip replacement is a relatively safe procedure. However, as with any surgery, there are certain risks involved that may include infection, bleeding, delayed healing, and loosening of the implant.