A total hip arthroplasty, or total hip replacement, is a surgical procedure to replace the hip joint with an artificial prosthesis. This
procedure is performed for the treatment of severe joint conditions causing hip dysfunction and pain. The two prosthetic components, the acetabular and the femoral stem and ball, model the anatomy of the original hip. The goal of the procedure is pain relief and restoring function to allow the patient to return to daily activities and hobbies.
The hip joint is a multi-axial ball and socket joint designed for stability and weight bearing. The hip is a synovial joint with an articulation between the acetabulum and the head of the femur. A branch of the obturator artery supplies the head of the femur. Hyaline cartilage covers the acetabular fossa and the head of the femur. A synovial membrane covers the ligament of head of femur and blends into the fibrous membrane. The fibrous membrane medially attaches to the outside of the acetabulum, and laterally to the intertrochanteric line of the femur. The ligaments that help stabilize the joint are the: iliofemoral ligament, pubofemoral ligament, ischiofemoral ligament.
- Avascular Necrosis
- Traumatic Arthritis
- Early degeneration of the joint from preexisting conditions
- A high occurrence of pain is preventing daily activities. The pain does not respond to conservative treatment i.e. NSAID
The surgeon has two options for the selection of the surgical implant. Both options are chosen for different reasons. It is important to have a discussion with the surgeon on what implant is most appropriate.
- Younger Patients
- More active
- Involves restricted weight bearing status the first 6 months after surgery
- Better outcomes for long term fixation
- Elderly patients
- Less physical demand
- Early fixation
- Loosening of implant in long term outcomes
1. Posterior lateral approach (Traditional)
- 8-12 inch incision
- Disruption of connective tissue and muscles
- More precautions post surgery
2. Direct Anterior approach
- 3-4 inch incision
- Tissue and muscle sparing
- Potentially no precautions post surgery
Steps during the surgery:
(steps 1-2 are dependent on surgical approach)
- The patient is placed in a lateral side-lying position with the affected hip exposed.
- The Surgeon makes an incision starting at the upper thigh that goes up towards the buttocks. The incision is made through the tissue, muscle, and capsule of the affected hip to expose the joint.
- The surgeon dislocates the hip joint and prepares the bone for the prosthesis by removing the head of the femur and reaming out the intermedullary canal. The socket is prepared by smoothing the bone down to make an even sphere.
- The cup and femoral stem are press fit into the joint. The prosthesis is roughened to encourage bone growth during recovery to secure the prosthesis.
- A trial prosthesis ball is connected to the femoral stem. The surgeon checks the fit through all directions. Once the correct fit is chosen, the permanent head is placed and the patient’s range of motion in the hip is rechecked.
- The Surgeon closes up the wound and dresses it with gauze. Some surgeons will place a drain to help remove excess fluids.
- An abduction brace is placed on the surgical leg to prevent adduction, a position of risk for dislocation.
Post Operative Treatment
Surgeons instruct patients on three common precautions following surgery. Patients are also instructed in proper weight bearing. The surgeon might remove or add different precautions based on each individual surgery. The three main precautions are as follows:
- Do not flex hip past 90 degrees
- Do not Internally rotate the hip; keep toes straight forward
- Do not adduct the hip; do not cross midline
Weight bearing status: Cement implants are weight bearing as tolerated; Cementless implants are touch down weight bearing for 6-8 weeks post-surgery.
Goals for physical therapy include :
- Protecting against dislocation of the joint
- Gaining range of motion
- Strengthening the hip and knee muscles
- Regaining functional activity
Bed exercises will be initiated post-surgery day 1. These exercises can include:
- Ankle pumps
- Quad sets
- Glute sets
- Abduction slides
- Short arc quads
- Heel slides *with bed flat
Standing exercises can be used to progress the program
- Heel raises
- Small step ups forward and lateral
Other areas of focus are:
- Transfer training
- Gait training
- Stair training
• Dislocation of the artificial joint
• Blood loss
• Venous Thromboembolism
• Injury to nerve or blood vessels
• Loosening of the prosthesis over time
• Pressure Sores- from sitting or lying in one position too long without repositioning
- American Academy of Orthopaedic Surgeons : http://orthoinfo.aaos.org/topic.cfm?topic=a00377
- Medline Plus http://www.nlm.nih.gov/medlineplus/hipreplacement.html
- Mayo Clinic : http://www.mayoclinic.com/health/hip-replacement/MY00235