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· DOS Abstracts
Bone remodelling of the of the tibia after total knee
arthroplastry with uncemented tibia implants
Mikikel Rathsach Andersen, Nikolaj Winther, Thomas Lind, Henrik Schrøder,
Michael Mörk Petersen
Knæklinikken, Ortopædkirurgisk afdeling, Gentofte Hospital, Region
Hovedstaden; Ortopædkirurgisk klinik U, Hovedortocenteret, Rigshospitalet,
Region Hovedstaden
Background:
Loss of bone stock as a response to the bone trauma and post-
operative immobilisation is a well known complication to joint replacement sur-
gery.
Purpose / Aim of Study:
This study investigates the adaptive bone remodel-
ling of the tibia, after total knee arthroplasty (TKA) with two uncemented total
knee arthroplastries.
Materials and Methods:
We performed 1 year follow up of 54 patients (mean
age 61,7 (38-70) years, 28/26=x/y, BMI 29,5) that received an uncemented
TKA in a prospective randomised controlled trial, where the patients were ran-
domised into two groups that recieved different tibial components. The TKAs
were performed using the uncemented Zimmer Nexgen® trabecular metal tib-
ia implants with either a monoblock (A) or modular (B) polyethylene design.
Measurements of bone mineral density (BMD) were done postoperatively and
after 3, 6, and, 12 months. BMD was measured in 3 regions of interest (ROI)
medially, laterally, and distally around the tibial component. Statistics: Paired and
unpaired t-test (P< 0.05 were considered significant).
Findings / Results:
Significant changes in BMD after 12 months of follow-up
was only seen in group A, where BMD decreased medially by 9.4% (p=0.002)
and laterally by 6.7% (p=0.009). When comparing BMD changes between the
groups after 12 months differences was found in the medial (p=0.01) and lat-
eral (p=0.053) ROIs.
Conclusions:
A significantly different bone remodelling pattern of the proximal
tibia was seen in the two groups with a higher degree of bone loss seen in knees
that received the monoblock design.
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