Hip and knee arthroplasty have been a boon to mankind. Prior generations suffered mightily with end-stage arthritis, having no means of relieving pain and restoring function once joint cartilage was lost. Individuals struck with “rheumatism” lost their ability to meaningfully ambulate and engage in activity. Beginning in the 1960s, joint replacement offered these individuals the opportunity to restore their ambulatory ability and to resume their activities. These surgeries and the prostheses used in them were continuously modified in the ensuing 50 years, providing off-the-shelf availability to fit nearly any individual.
Although these procedures were very successful in appropriate individuals, they were initially undertaken with caution. Highly specialized individuals in highly specialized centers performed joint replacements on carefully selected patients. As medical procedures popularize and proliferate, more patients request them from more surgeons. Consequently, the indications for arthroplasty loosened, and the fear of complications lessened. This allowed more people to undergo joint replacement, but at a great cost not only to society, but to the individuals themselves, as periprosthetic infection is a devastating complication. Surgeons and hospital systems have therefore become increasingly selective with regard to patients, procedures, and the surgeons who perform them, as it became obvious that an infected or dysfunctional prosthetic joint is far worse than an arthritic joint.
Performing a hemiarthroplasty on the hip is a procedure whereby only the femoral portion of the joint is replaced. In this way, the femoral head is removed, and a prosthesis is placed in the remaining femoral bone and allowed to articulate with the acetabulum.
Hemiarthroplasty has a fairly small number of indications including displaced femoral neck fractures in elderly individuals, oncologic resections of the femur, and avascular necrosis (Figure 8–1). Contraindications to hemiarthroplasty include substantial arthritic changes of the acetabular cartilage and active infection.
An anteroposterior radiograph demonstrating a cemented hip hemiarthroplasty performed for a fracture of the femoral neck.
The success of hemiarthroplasty depends greatly upon its indications. In elderly individuals who suffer displaced femoral neck fractures and who lack arthritic changes, hemiarthroplasty has traditionally provided lifelong relief from pain and allows the individual to ambulate. Functional success is strongly dependent upon preinjury function, as most individuals require more ambulatory assistance after this type of injury and surgery than they had at baseline before injury. The functional results in oncologic resections have rarely been studied, as the focus was oncologic success and mild pain or functional deficiencies were considered secondary issues. Use of hemiarthroplasty in avascular necrosis is controversial because many patients do not have complete pain relief. This is balanced by the risk of complications, especially prosthetic dislocation, being substantially higher after total hip arthroplasty (THA) being done for avascular necrosis.