Hemi Versus Total Hip Arthroplasty
Moderate evidence supports a benefit to total hip arthroplasty in properly selected patients with unstable (displaced) femoral neck fractures.

One high strength (Keating et al 50) and four moderate strength studies (Blomfeldt et al 80, Hedbeck et al 81, Macaulay et al 82, van den Bekerom et al 83) examined this question.  Though various methodologic issues preclude strong recommendations, the evidence on this question generally demonstrates a benefit to patients who received total hip arthroplasty (Hedbeck et al 81, Macaulay et al 82).  This benefit was largely manifest in lower pain related scores and lower revision rates for acetabular wear.  Mortality rates and infection rates were largely unaffected within the first 4 years after treatment.

However, patient exclusion criteria in some of these studies also reflects the general bias amongst surgeons towards performing total hip arthroplasty in patients who are higher functioning and more likely to be independent community ambulators (Macaulay et al 82). Cautious decision making for lower functioning patients may be justified; studies also demonstrate a higher dislocation rate among total hip arthroplasty patients (van den Bekerom et al 83).

Risks and Harms of Implementing this Recommendation
Implementing this recommendation does not result in additional harm in the patient beyond that conferred by usual surgical risk. The choice of appropriate treatment requires discussion of risk and benefit with patients and families.  This may help determine which patients stand to benefit from the superior pain relief and lower likelihood of revision surgery conferred by total hip arthroplasty, and which patients whose preoperative function does not justify a surgical procedure involving greater risks.

Future Research
Further areas of investigation include whether potential delays in surgery occur when total hip arthroplasty is the chosen treatment, and whether this has an effect on postoperative morbidity. Another important but unanswered question is whether the demand for total hip arthroplasty following fracture can be met by surgeons who currently employ hemiarthroplasty, or if the increasing use of total hip arthroplasty by less experienced surgeons will offset potential benefits seen in previous studies.