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· DOS Abstracts
EOS imaging for assessing lower limb alignment and
implant positioning after Total Knee Arthroplasty
(TKA)
Kirill Gromov, Viktor Hansen, Dov Goldvasser, Orhun Muratoglu,
Henrik Malchau, Anders Troelsen
Department of Orthopaedic Surgery, Copenhagen University Hospital
Hvidovre; Harris Orthopaedic Laboratory, Massachusetts General Hospital
Background:
The lower limb axis and implant alignment are traditionally as-
sessed to evaluate the success of primary TKA surgery. EOS imaging is a novel
technology that can provide the surgeon with full body images, while exposing
the patient to significantly lower radiation dosage
Purpose / Aim of Study:
In this study we seek to evaluate the precision of
EOS imaging for measuring lower limb axes as well as implant alignment follow-
ing primary TKA
Materials and Methods:
32 patients that underwent TKA and had EOS radi-
ography performed pre- and postoperatively were included in the study. Hip-
Knee-Ankle (HKA) axis and tibiofemoral angle (TFA) was measured pre- and
postoperatively. Tibial and femoral implant alignment was assessed in anterior-
posterior (AP) and lateral plane in respect to anatomical as well as mechanical
axis. Two readers each assessed all images with reassessment by one reader..
Intra- and inter-reader variability was assessed by the mean difference and
95% limits of agreement (LoA)
Findings / Results:
95% LoA for postoperative HKA and TFA were +/- 0.41°
and +/-0.80°, respectively. 95% LoA for AP implant alignment in respect to
the mechanical axes were all within +/-0.80° and within +/-1.47° in respect
to anatomical axes. 95% LoA for tibial lateral implant alignment were within +/-
1.50° and within +/-3.65° for femoral lateral implant alignment. There were no
systematic differences between observers. Mean difference and LoA for tibial
component alignment in the AP plane in respect to the mechanical compared to
anatomical axis was -0.18° +/-2.86°
Conclusions:
EOS imaging can be used for precise measurements of lower limb
axis and implant alignment following primary TKA. This allows EOS imaging to be
potentially implemented as a clinical tool for evaluation of results following TKA
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