Total Hip Arthroplasty for Hip Fracture
David J. Mayman, MD
Dr. Mayman or an immediate family member is a member of a speakers’ bureau or has made paid presentations on behalf of Smith & Nephew; serves as a paid consultant to Smith & Nephew; has stock or stock options held in OrthAlign; and serves as a board member, owner, officer, or committee member of the Knee Society.
Introduction
Hip arthroplasty for treatment of hip fracture can be an excellent treatment option that can allow for a very fast recovery to prefracture level of activity.
Historically, total hip arthroplasty (THA) has been used in a limited amount for hip fractures because of risk of dislocation, infection, and periprosthetic fracture. Hemiarthroplasty is commonly performed in elderly patients for displaced fractures as a reliable means of maintaining mobility. Fixation is commonly performed in younger patients or in nondisplaced fractures in the elderly to preserve the native hip. However, the challenges of reduction, fixation, and healing of femoral neck fractures have made total hip replacement a good option for the active older patient while avoiding the problem of acetabular wear with hemiarthroplasty. The increasing success of modern THA for degenerative conditions in younger patients has led to its growing popularity for hip fractures in the middle-aged or older active patient. Hemiarthroplasty is still more commonly performed in elderly patients, although pain relief has been shown to be better with total hip replacement.
Anatomy
Hip fractures come in many forms. The definition of the fracture is based on the anatomic location. The more proximal in the femur the fracture is, the simpler THA becomes.
Femoral Neck Fracture
Femoral neck fractures occur between the femoral head and the trochanters. This fracture is typically at or above the level at which the femoral neck would be cut for a standard total hip replacement.
Basicervical Fracture
Basicervical fractures occur just above the intertrochanteric ridge. They do not involve either the lesser or greater trochanter and typically below the level of where a neck cut would be made for a THA. Revision hip implants may be required in these cases given the lack of supporting bone remaining in the femoral calcar to support a primary hip prosthesis.
Intertrochanteric Fracture
Intertrochanteric fractures involve the lesser trochanter, the greater trochanter, or both. THA for this fracture pattern is performed uncommonly—these fractures are most commonly fixed with an intramedullary nail or a plate and screws, and tend to heal. If a THA is performed in this case, usually after failure of fixation, revision femoral implants need to be used.
The large majority of total hip replacements done for hip fractures are done for displaced femoral neck fractures (Figure 38.1).
Surgical Procedures
THA resurfaces the acetabulum with a socket and puts a stem into the canal of the femur. A liner is placed in the socket and a ball is placed on a stem that fits into the canal of the proximal femur. Today, the majority of acetabular components are titanium implants with a porous ingrowth surface. Cemented femoral implants are still used commonly in elderly patients or patients with questionable femoral bone quality. The socket then has a modular liner inserted into it. These liners are usually made of cross-linked polyethylene.
The femoral implant is either made of titanium with a porous ingrowth surface or is cemented into the femur for fixation. The decision of whether to use a cemented or uncemented femoral implant is based on bone quality and surgeon preference.
The surgery can be done through a number of surgical approaches. The approach used for surgery and surgeon preferences will affect the limitations or precautions in the early postoperative period.
Direct Anterior Approach
The direct anterior approach utilizes the intramuscular plane between the tensor fascia lata and the rectus femorus muscle. Exposure to the acetabulum is relatively simple, but exposure of the femur is more difficult. Posterior structures are left intact. The risk of posterior instability is low, but the risk of anterior instability is higher.
Anterolateral Approach
The anterolateral approach has a low risk of dislocation, but the anterior portion of the gluteus minimus and gluteus medius are taken off of the trochanter for the procedure, and have to heal back to the trochanter after surgery.
Direct Lateral Approach
The direct lateral approach incorporates an osteotomy of the greater trochanter. This approach is not commonly used today; it requires time for the osteotomy to heal.
Posterolateral Approach
The posterolateral approach is the most common approach used for hip arthroplasty in the United States today. The abductors are left intact, but the posterior capsule, piriformis tendon, and conjoined tendon are released from the posterior aspect of the femur, necessitating posterior hip precautions during the healing period.
Early Postoperative Rehabilitation
Early postoperative rehabilitation is highly dependent on the surgical approach used. Early ambulation is encouraged to minimize postoperative medical risks such as deep vein thrombosis (DVT), pulmonary embolism, and pneumonia.
Most patients will be weight bearing as tolerated immediately after surgery unless a complication such as fracture is noted.
Direct Anterior Approach
Weight bearing, as tolerated.
Avoid hyperextension and external rotation.
Progress from a walker to a cane to no ambulatory aids, as tolerated.
Anterolateral Approach
Weight bearing, as tolerated.
Avoid hyperextension and external rotation.
Progress from a walker to a cane, but a cane should be used, and avoid active abduction to protect the abductor repair for the first 6 weeks.
Direct Lateral Approach
Weight bearing, as tolerated.
Avoid flexion, adduction, and internal rotation.
Progress from a walker to a cane; a cane should be used to protect the osteotomy for the first 6 weeks.
Posterolateral Approach
Weight bearing, as tolerated.
Avoid flexion, adduction, and internal rotation.
Progress from a walker to a cane to no ambulatory aids, as tolerated.
Posterior Hip Precautions
Hip replacement done through a posterior approach leaves the abductors fully intact, but releases the piriformis tendon and the conjoined tendon from the back of the femur. The posterior capsule is then released. The hip is dislocated by a combination of hip flexion, adduction, and internal rotation.
Posterior hip precautions are designed to avoid harming the repair of the posterior structures or dislocation of the hip joint.
No hip flexion past 90°.
No adduction past neutral.
No internal rotation of the hip (Figure 38.2).
Early Postoperative Rehabilitation Exercises
Ankle Pumps
Slowly push the foot up and down. Do this exercise several times as often as every 5 or 10 minutes. This exercise can begin immediately after surgery (Figure 38.3).
Ankle Rotations
Move the ankle inward toward your other foot, then outward away from your other foot.