Unstable Femoral Neck Fractures - Total Arthroplasty vs. Hemi Arthroplasty
In properly selected patients with unstable (displaced) femoral neck fractures, there may be a functional benefit to total hip arthroplasty over hemi arthroplasty at the risk of increasing complications.

Rationale

This recommendation was downgraded from Strong to Moderate strength due to effect size. 

Four high strength (Chammout 2019, Hedbeck 2011, Keating 2005, van den Bekerom 2010) and ten moderate strength studies (Blomfeldt 2005, Cadossi 2013, Health Investigators 2019, Iorio 2019, Li 2017, Parker 2019, Ren 2017, Sharma 2016, Ukaj 2019, Xu 2017) examined this question. The evidence demonstrates a small functional outcome benefit to patients who received total hip arthroplasty. Hemi arthroplasty was associated with a small decrease in dislocation and instability. Mortality rates were largely unaffected within the first 4 years after treatment.

The strength of the evidence is strong. However, the effect size is small, which led the expert panel to unanimously downgrade this recommendation to moderate. Patient exclusion criteria in some of these studies reflect the general bias amongst surgeons towards performing total hip arthroplasty in patients who are higher functioning and more likely to be independent community ambulators. Cautious decision making for lower functioning patients may be justified considering the bias and risk for complications.

Benefits/Harms of Implementation

Implementing this recommendation does not result in additional harm to the patient beyond that conferred by usual surgical risk. The choice of appropriate treatment requires discussion of risk and benefit with patients and families (shared decision making). This may help determine which patients might benefit more from functional improvement or avoiding complications including those patients whose preoperative function does not justify a surgical procedure involving greater risks. 

Implementing this recommendation is likely to lead to greater expenditure. Total hip arthroplasty implants are priced higher than implants for hemi arthroplasty. Procedural and professional fees are higher for total hip arthroplasty than for hemi arthroplasty. The slight increase in complications with total hip arthroplasty may also generate additional charges.

Future Research

Further areas of investigation include whether potential delays in surgery occur when total hip arthroplasty is the chosen treatment, and whether this influences 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 hemi arthroplasty, or if the increasing use of total hip arthroplasty by less experienced surgeons will offset potential benefits seen in previous studies.