Revision Total Hip Replacement
A revision total hip replacement is required when an initial total hip replacement fails from one of a variety of causes. These can include osteolysis (weakening and breakdown of bone) and subsequent subsidence (loosening), infection, recurrent dislocation due to incorrect positioning of the prosthetic components, and peri-prosthetic fracture (fracture through the thigh bone around the prosthesis).
When determining if someone is a good candidate for revision total hip replacement, the first step is to figure out why the prosthesis has failed. This will dictate which surgical approach is used.
Joint Failure due to an Infection
The presence of an infection dramatically changes the approach to revising a total hip replacement as the infection must be cleared before a new hip replacement is performed. If there is an infection, a debridement (cleaning out of the hip joint) and two-staged replacement is usually required:
- First stage – This includes cleaning out the infected hip joint and placing a temporary antibiotic spacer. The spacer is made of cement and contains an antibiotic that slowly leaks out to the surrounding area for a 6-week period to clear the infection. In addition to the antibiotic spacer, antibiotics are given intravenously (through the veins) to maximize treatment.
- Second stage – Once the hip joint area is free of infection, a definitive revision total hip replacement is performed using a new implant.
Joint Failure from Other Causes
If failure is due to peri-prosthetic fracture, the fracture will likely need to be formally fixed, and the prosthesis may need to be revised (replaced).
Loosening (subsidence) due to osteolysis
More commonly, the hip replacement will fail due to loosening (subsidence) as a result of a reactive process leading to inflammation of the synovium (a thin layer of cells lining the joint that secretes a lubricating fluid for smooth joint movement). The inflammation is secondary to release of particles from wearing of the artificial joint components, such as plastic or metal particle debris. This occurs over time as the two sides of the joint move against each other. The metal and/or plastic (polyethylene) particles become lodged in the synovium and cause inflammation. Inflammation ultimately leads to breakdown and weakening (osteolysis) of bone around the prosthesis, otherwise known as subsidence. The breakdown of bone as well as wear of the prosthetic components causes implant loosening. Ultimately, the joint stops functioning properly as a result leading to pain.
If the cause of failure is determined to be synovitis and subsequent prosthetic subsidence, the femoral and/or acetabular components of the hip replacement will be removed. A new prosthesis, which is often specialized to compensate for the loss of bone (osteolysis), will replace the old prosthesis. Additionally, a bone graft (bone taken from another part of the body or cadaver bone) may be used to replace missing bone that was crucial to proper adherence and stability of the hip replacement.
A revision total hip replacement may involve replacing: only the lining of the acetabulum (hip socket); the entire acetabulum (hip socket) prosthesis; the femoral (thigh) prosthesis; or all of these components. In general, a revision total hip replacement is a more complicated procedure than a primary total hip replacement and in many instances it is substantially more complicated. This often means that the surgery takes longer, has a longer recovery period, and a higher overall complication rate when compared to first-time (primary) total hip replacements.
Recovery from a revision total hip replacement is often more involved than for a primary total hip replacement. Recovery includes gradual weight-bearing as tolerated on the prosthetic hip using an assistive device such as a cane or walker. The amount of weight placed on the artificial hip is slowly increased until full weight-bearing is achieved. Another component of recovery is pain management, which can be accomplished by using pain medications such as NSAIDs if they are considered safe for the individual to use. Physical therapy and home exercises will also be recommended in order to regain strength and range of motion in the artificial hip and surrounding area.
Complications from revision total hip replacement tend to occur at a higher rate than with primary total hip replacement. Potential complications include:
- Prosthetic loosening
- Surgical site infection
- deep vein thrombosis (blood clot) and pulmonary embolism
- Heterotopic ossification (bone formation in an area where it should not form)
- Leg-length discrepancy, or differences in length between the two legs
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Keywords: revision total hip replacement, revision total hip arthroplasty, failed total hip replacement, failed total hip arthroplasty, hip osteolysis