Hemiarthroplasty or Total Hip for Femoral Neck Fracture
An older adult with a displaced femoral neck fracture will almost always get a new hip, and replacing half or all of the joint trades a small gain in function against a higher risk of dislocation.
Key terminology
- Femoral neck
- This short segment joins the femoral head to the shaft and sits inside the hip capsule. A break here is intracapsular, so it threatens the head's blood supply.
- Medial femoral circumflex artery (MFCA)
- This branch of the profunda femoris wraps behind the hip and enters the capsule. Its deep branch gives the retinacular vessels that feed most of the femoral head.
- Avascular necrosis (AVN)
- This is death of bone from loss of its blood supply. In the hip it makes the femoral head collapse, which is a main reason fixation of a displaced fracture goes wrong.
- Garden
- This system grades femoral neck fractures I to IV on the AP film. Grades I and II are nondisplaced and grades III and IV are displaced.
- Hemiarthroplasty
- This operation replaces the femoral head and neck with a metal stem and ball. The acetabulum is left alone, so the metal head rides on the patient's own cartilage.
- Total hip arthroplasty (THA)
- This operation replaces both the femoral head and the acetabulum with a lined cup. It removes cartilage wear as a problem but adds dislocation risk and OR time.
Takeaways
- A displaced femoral neck fracture tears the main blood supply to the femoral head. The deep branch of the MFCA is the primary source for the head. Inside the capsule it runs along the posterosuperior neck and splits into 2 to 4 retinacular vessels, so displacement of the neck tears them → avascular necrosis (AVN) and nonunion (Gautier et al, J Bone Joint Surg Br 2000;82:679-683, PMID 10963165).
- Arthroplasty beats internal fixation for the displaced femoral neck fracture in an older adult. Across 14 trials and 1901 patients, revision surgery after arthroplasty had a relative risk of 0.23 vs fixation, at the cost of more infection (RR 1.81), blood loss and OR time. In one RCT secondary surgery ran 39% after fixation vs 5% after bipolar hemiarthroplasty and 9% after total hip (Bhandari et al, J Bone Joint Surg Am 2003;85:1673-1681, PMID 12954824; Keating et al, J Bone Joint Surg Am 2006;88:249-260, PMID 16452734).
- Garden grades I to IV boil down to nondisplaced (I-II) and displaced (III-IV). Surgeons agree only moderately on the full 4-stage grade (mean interobserver κ 0.49). The simple displaced vs nondisplaced split is far more reliable (κ 0.71 on the AP view alone and 0.76 with a lateral), and it drives the fix vs replace decision (Cazzato et al, BMC Musculoskelet Disord 2022;22:1063, PMID 35078436; Macke et al, Front Surg 2021;8:652528, PMID 34109207).
- Total hip and hemiarthroplasty lead to about the same reoperation rate. HEALTH randomized 1495 patients 50 y/o and older who walked without help from another person. A secondary hip procedure within 24 months occurred in 7.9% after total hip vs 8.3% after hemiarthroplasty (HR 0.95, 0.64-1.40), and mortality was similar at 14.3% vs 13.1% (HEALTH Investigators et al, N Engl J Med 2019;381:2199-2208, PMID 31557429).
- Total hip buys a small gain in function at the price of more dislocations. In HEALTH, dislocation ran 4.7% after total hip vs 2.4% after hemiarthroplasty, and WOMAC function gains were called clinically unimportant. In a Finnish registry, THA for fracture had 3.0x the hazard of dislocation revision vs THA for arthritis (HEALTH Investigators et al, N Engl J Med 2019;381:2199-2208, PMID 31557429; Panula et al, Scand J Surg 2020;110:351-358, PMID 32500836).
- Older small trials favored total hip, and the pooled evidence no longer shows a clear advantage. Trials of 81 and 120 patients favored total hip on hip scores, and every surviving hemiarthroplasty at 9 years had acetabular erosion. A meta-analysis of 16 RCTs (3084 patients) found no difference in revision, function, dislocation or mortality, though nearly half the patients came from HEALTH (Avery et al, J Bone Joint Surg Br 2011;93:1045-1048, PMID 21768626; Blomfeldt et al, J Bone Joint Surg Br 2007;89:160-165, PMID 17322427; Ekhtiari et al, J Bone Joint Surg Am 2020;102:1638-1645, PMID 32732709).
- AAOS and NICE still favor total hip for the fit, independent walker. AAOS 2021 says total hip may give a functional benefit in properly selected patients, with more complications (moderate strength). NICE's 2023 update, after HEALTH, still offers total hip over hemiarthroplasty to patients who walk outdoors with no more than a stick and have no cognitive or medical bar (O'Connor and Switzer, J Am Acad Orthop Surg 2022;30:e1291-e1296, PMID 36200817; Ong and Vindlacheruvu, Age Ageing 2023;52:afad110, PMID 37389557).
- Cognitive impairment raises dislocation risk and steers the choice toward hemiarthroplasty. In a case-control study of hemiarthroplasty dislocation, dementia, longer surgical delay and a shorter residual femoral neck were all more common in patients who dislocated. One-year mortality was 44% after a dislocation vs 14% in matched controls, and 67% needed more surgery (Bellostas et al, Injury 2024;55 Suppl 5:111737, PMID 39581656).