Article

Periprosthetic fracture is a devastating complication of
total knee replacement (TKR). Most published studies have not comprehensively
assessed clinical and demographic predictors.
We wanted to determine the
incidence and predictors of postoperative periprosthetic fracture after primary
and revision TKR. METHODS: We used prospectively collected data in
the Mayo Clinic Total Joint Registry on all patients who underwent primary or
revision TKR at the Mayo Clinic, Rochester, from 1989 through 2008. We assessed
incidence of postoperative periprosthetic fractures and modifiable (comorbidity,
body mass index) and unmodifiable factors (age, sex, operative diagnosis, ASA
class, previous cardiac disease, and previous thromboembolic disease) as
predictors of postoperative periprosthetic fractures. We used
multivariable-adjusted Cox regression analyses separately for primary and
revision TKR. RESULTS: 12,914 patients underwent 17,633 primary TKRs and 3,286
patients underwent 4,090 revision TKRs during the period 1989-2008. 1.1% of
patients (188/17,633) after primary TKR and 2.5% of patients (104/4,090) after
revision TKR sustained a postoperative periprosthetic fracture on or after
postoperative day 1. Older age was associated with lower risk of periprosthetic
fractures after primary TKR (p < 0.001). Compared to </= 60 years, risk was lower
for ages 61-70 years (hazard ratio (HR) = 0.5, 95% confidence interval (CI):
0.3-0.7)) and 71-80 years (HR = 0.6, CI: 0.4-0.8), but not for age > 80 years (HR
= 0.9, CI: 0.5-1.6). In revision TKR cohort, a diagnosis of non-union (HR = 4.9,
CI: 1.2-20), infection (HR = 2.9, CI: 1.3-6.4) or previous surgery with
components removed (HR = 2.1, CI: 1.3-3.4) increased the risk of postoperative
periprosthetic fracture, compared to a diagnosis of loosening/wear/osteolysis.
INTERPRETATION: We identified significant risk factors for periprosthetic
fracture after primary and revision TKR. Patients with these risk factors can be
informed by their surgeons of increased risk of this uncommon, but serious complication of TKR.

Langue : ANGLAIS