Differences in subsidence rate between alternative designs of a commonly used uncemented femoral stem

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• 作者：Munnan Al-Najjim^a ; ^{malnajjim@yahoo.com" class="auth_mail" title="E-mail the corresponding author} ; Usman Khattak^a ; Juluis Sim^b ; Iain Chambers^a
• 关键词：Femoral stems ; Corail stem ; Uncemented
• 刊名：Journal of Orthopaedics
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：13
• 期：4
• 页码：322-326
• 全文大小：526 K

文摘

Measurement of early subsidence of uncemented femoral stems can be used to evaluate the likelihood of long term stem component loosening and therefore clinical failure.

Our aim was to evaluate the factors associated with subsidence in collared and uncollared versions of the Corail femoral stem.

Methods

121 hips in 113 consecutive patients were studied, operated on by two surgeons in our hospital differing in their choice of Corail stem. This gave two groups of patients with 66 hips having collared stems and 55 hips having uncollared. We recorded patients’ age, sex, ASA grade and BMI. Radiographs post-operatively at day 1, 6 weeks and 1 year were evaluated measuring subsidence, angulation, signs of stability and fixation, and canal fill ratio at the metaphysis and diaphysisafter correcting for magnification errors by calibration using femoral head size.

Results

Clinically significant subsidence (>3 mm) occurred in 7.6% of collared and 10.9% of uncollared stems, all within 6–8 weeks, but did not reach statistical significance (p = 0.345). Revision for symptomatic loosening was required in 1 patient in each group (1.5% collared versus 1.8% uncollared).

Discussion

Early subsidence of Corail femoral stem should alert surgeons to closer patient follow-up as the rate of early revision is 18% in stems with >3 mm of subsidence. However, the presence of a collar does not seem to be protective.