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In a multicenter study, patients who underwent total hip arthroplasty (THA) for a femoral neck fracture were more likely to experience a second fracture and require revision surgery if a cementless rather than cemented femoral implant was used.

This study was presented at the 2023 annual meeting of the American Academy of Orthopaedic Surgeons and was previously published by The Journal of Arthroplasty.

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“Femoral neck fractures are very common in the elderly and are a major cause of morbidity and mortality in this population,” said study author Alexander McLawhorn, MD, a hip and knee orthopedic surgeon at Hospital for Special Surgery.

“Several national registry studies have demonstrated a lower risk of overall revision surgery, and specifically revision for periprosthetic fracture, with cemented femoral fixation. Despite this overwhelming data, many patients in the United States receive cementless fixation, including patients who have sustained femoral neck fractures.”

Patients Classified by Dorr Type

The retrospective study analyzed 709 THAs (199 cemented, 510 cementless) performed for femoral neck fractures between 2006 and 2020 at 3 large academic institutions: Hospital for Special Surgery, Indiana University Health, and University Hospitals Cleveland Medical Center. The researchers reviewed patient demographics, perioperative characteristics, and radiographs. They then categorized patients according to the Dorr classification system: Dorr type A, B, or C bone. This system is widely used to evaluate femoral bone quality.

“To our knowledge, this was the first non-registry study comparing outcomes of cemented versus cementless total hip replacement for acute femoral neck fractures [by] examining the influence of various patient factors, including bone quality,” said lead author Michael Kheir, MD, who participated in the study as a fellow from Hospital for Special Surgery. He is now an orthopedic surgeon specializing in hip and knee replacement at the University of Michigan.

“The primary purpose [of the study] was to compare complication rates between both groups, including periprosthetic fractures, aseptic revision, dislocation, and mortality rates.”

Study Findings

The prevalence of Dorr type bone was:

• 1% type A
• 3% type B
• 6% type C

Patients receiving cemented implants were older, had a lower BMI, were more often women, and were more likely to have a pre-existing diagnosis of osteoporosis and Dorr C bone type than patients receiving cementless implants.

Patients with cementless implant stems had higher all-cause aseptic femoral revision (5.1% vs 0.5%) and periprosthetic femoral fracture (4.3 vs 0%) rates than patients with cemented stems. Bone classification played a major role: For patients with cementless implants, each successive Dorr grade had a higher fracture rate: Dorr A =2.3%, Dorr B = 3.7%, and Dorr C = 15.9%. There were no between-group differences for rates of dislocation, revision due to infection, or mortality. The study found an equal distribution of male and female patients who sustained a fracture.

“While femoral fractures occurred in patients with all types of bone quality, Dorr C bone was particularly prone, with an alarmingly high fracture rate when using cementless stems,” Dr. Kheir noted.

“All of the fractures requiring a revision surgery occurred in cementless cases, suggesting that cemented stems may minimize this complication, regardless of patient sex or Dorr classification.”

Source

Kheir MM, Dilley JE, Speybroeck J, et al. The influence of Dorr type and femoral fixation on outcomes following total hip arthroplasty for acute femoral neck fractures: a multicenter study. J Arthroplasty. 2023 Apr;38(4):719-725. doi: 10.1016/j.arth.2022.10.028. Epub 2022 Oct 22.