DOS 2017

DOS Kongressen 2017 ·

113

Preoperative systemic bone quality does not affect

tibial component migration in knee arthroplasty. A 2

year RSA study of 101 consecutive patients.

Karina Nørgaard Linde, Katriina Bøcker Puhakka, Bente Lomholt Langdahl, Kjeld

Søballe, Inger Krog-Mikkelsen, Frank Madsen, Maiken Stilling

Orthopaedic Research Unit, Department of Clinical Medicine, Aarhus Univer-

sity Hospital, Denmark; Department of Radiology, Aarhus University Hospital,

Denmark; Department of Endocrinology and Internal Medicine, Aarhus Univer-

sity Hospital, Denmark; Department of Orthopaedic Surgery, Aarhus University

Hospital, Denmark

Background:

Bone quality and other preoperative predictive factors may affect

the survival of knee arthroplasty. Early implant migration in the first 2 postop-

erative years measured with RSA has been shown to predict long- term implant

survival of knee arthroplasty.

Purpose / Aim of Study:

To explore the association between preoperative

bone quality and tibial component (TC) migration.

Materials and Methods:

Longitudinal case study investigating the predictors

of TC migration (RSA) at 2 years postoperative follow up in 101 patients (65 fe-

male) with total knee arthroplasty (TKA) or unicompartmental knee arthroplas-

ty (UKA). Three TCs were investigated: cementless NexGen trabecular-metal

monoblock, cemented NexGen stemmed, and cemented Oxford medial UKA.

Predictors comprised clinical risk factors for osteoporosis, DXA, bone turnover

markers (BTMs), and osteoarthritis grade. Clinical outcome was assessed by

OKS. The acceptable migration threshold at 1 year was set at 0.54mm MTPM

according to Piljs et al. (Acta Orthop 2012).

Findings / Results:

Patients had a mean age of 67.7 years (range 39-87),

and 15 had osteoporosis. At 1 year, 52.5 % had a migration below the “ac-

ceptable” threshold, and the remaining TCs were considered “at risk” for later

premature failure. There was no significant difference in BTMs and the grade

of osteoarthritis between groups below and above the acceptable migration

threshold (p>0.07), and mean total OKS score was similar between the two

groups (p=0.65). We found no difference in TC MTPM at 2 years (3 implant

types combined) comparing patients with and without osteoporosis (p=0.34).

Implant sub-type TC MTPM migration was also alike for patients with and with-

out osteoporosis (p>0.06).

Conclusions:

Migration of tibial components was not affected by preoperative

osteoporosis, bone turnover markers and local osteoarthritis grade in the knee.

No conflicts of interest reported

65.