Primary Hip Replacement

What is Primary Hip Replacement?

Primary hip replacement or hip arthroplasty is a surgical procedure in which the worn out or damaged parts of the hip joint are removed and replaced with artificial components called prostheses or implants that are made of metal, plastic, or ceramic. The main objective of the procedure is to relieve hip pain and restore normal range of motion and function to the hip joint when conservative treatment, such as medications, injections, and physical therapy have failed to provide desired results.

Anatomy of the Hip

The hip joint is one of the body's largest weight-bearing joints and is the point where the thighbone (femur) and pelvis (acetabulum) join. It is a ball-and-socket joint in which the head of the femur forms the ball, and the pelvic acetabulum forms the socket. The joint surface is covered by smooth articular cartilage that cushions and enables smooth movement of the joint. The bones are held together by bands of tissue called ligaments that provide stability to the joint.

Indications for Primary Hip Replacement

Your surgeon may recommend primary hip replacement if you have significant pain, inflammation, and damage to your hip joint due to conditions such as:

• Osteoarthritis
• Rheumatoid arthritis
• Septic arthritis
• Tumour in the hip joint
• Osteonecrosis (avascular necrosis)
• Dislocation of the hip joint
• Severe hip joint fracture or trauma
• Skeletal dysplasia (disorders that cause abnormal bone growth)
• Severe hip joint pain that limits your activities of daily living, such as walking or climbing stairs

Preparation for Primary Hip Replacement

Preoperative preparation for a primary hip replacement may involve the following steps:

• A review of your medical history and a physical examination are performed by your doctor to check for any medical issues that need to be addressed prior to surgery.
• Depending on your medical history, social history, and age, you may need to undergo tests such as blood work and imaging to help detect any abnormalities that could compromise the safety of the procedure.
• You will be asked if you have allergies to medications, anaesthesia, or latex.
• You should inform your doctor of any medications, vitamins, or supplements that you are taking or any conditions you have such as heart or lung disease.
• You may be asked to avoid medications such as blood thinners, aspirin, or anti-inflammatories for a specific period prior to surgery.
• You should refrain from alcohol or tobacco at least a few days prior to the surgery and several days after as it can hinder the healing process.
• You should not consume any solids or liquids at least 8 hours prior to surgery.
• You need to arrange for someone to drive you home after surgery.
• Signed informed consent will be obtained from you after the pros and cons of the surgery have been explained in detail.

Procedure for Primary Hip Replacement

The surgery is performed under general anaesthesia. 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 socket is cleaned, and the damaged or arthritic bone is removed using a reamer. The acetabular component is inserted into the socket using screws, or occasionally, bone cement. A liner made of plastic, ceramic, or metal is placed inside the acetabular component. 

The femur or thighbone is then prepared by removing the arthritic bone using special instruments to exactly fit the new metal femoral component. The femoral component is then inserted into the femur either by a press fit or using bone cement. Then the femoral head component made of metal or ceramic is placed on the femoral stem. All the new parts are secured in place using special cement. The muscles and tendons around the new joint are repaired and the incision is closed. 

Postoperative Care and Recovery

In general, postoperative care instructions and recovery after primary hip replacement may involve the following:

• You will be transferred to the recovery area where your nurse will closely observe you for any allergic/anaesthetic reactions and monitor your vital signs as you recover.
• Most patients may need to stay in the hospital for 2 to 3 days before discharge to home.
• You may notice pain, swelling, and discomfort in the hip area. Pain and anti-inflammatory medications are provided as needed for comfort.
• You will be placed on assistive devices such as crutches with instructions on restricted weight-bearing for a specified period of time. You are encouraged to walk with assistance as frequently as possible to prevent blood clots.
• Instructions on surgical site care and bathing will be provided to keep the wound clean and dry.
• Refrain from strenuous activities for the first few months and lifting heavy weights for at least 6 months. A gradual increase in activities over a period of time is recommended.
• An individualised physical therapy protocol will be designed to help strengthen hip muscles and optimise hip function once you are off crutches.
• Most patients are able to resume their normal activities in 3 to 4 weeks after surgery; however, returning to sports may take at least 6 months or longer.
• Refrain from driving until you are fully fit and receive your doctor’s consent.
• A periodic follow-up appointment will be scheduled to monitor your progress.

Risks and Complications

Primary hip replacement is a relatively safe procedure; however, as with any surgery, some risks and complications may occur, such as the following:  

• Infection
• Bleeding
• Damage to nerves and vessels
• Blood clots in the legs or lungs
• Anaesthetic/allergic reactions
• Continued pain or stiffness
• Fracture
• Dislocation
• Implant failure
• Leg length discrepancy
• The need for revision surgery