KNEE
Mid-term outcomes of computer-assisted total knee arthroplasty
Kazunari Ishida
•
Tomoyuki Matsumoto
•
Nobuhiro Tsumura
•
Seiji Kubo
•
Atsushi Kitagawa
•
Takaaki Chin
•
Tetsuhiro Iguchi
•
Masahiro Kurosaka
•
Ryosuke Kuroda
Received: 18 January 2010 / Accepted: 7 December 2010 / Published online: 14 January 2011
Ó Springer-Verlag 2011
Abstract
Purpose The aim of this study is to investigate the clin-
ical results of total knee arthroplasty (TKA) using a navi-
gation system after a minimum of 5 years.
Method Thirty cases of posterior-stabilized, TKA-
implanted using a computed tomography-free navigation
system were compared with 30 cases having matched TKA
of the same type implanted via a classical, manual tech-
nique. At mid term, a minimum of 5 years after surgery,
Knee Society scores (KSSs), Knee Society Functional
scores (KSFSs), range of motion (ROM), and radiographic
results of 27 patients in each group were assessed and
reported in this study.
Results The accuracy of the implantations in relation to
the coronal mechanical axis in the navigation group was
superior to that of the manual group (P \ 0.01). The
femoral rotational profile revealed the prosthesis in the
navigation group that was implanted with significantly less
internal rotation than the manual group. Mid-term 5-year
clinical results, including ROMs and KSSs, were signifi-
cantly better in the navigation group (P \ 0.01). KSFSs
were equally good in both the groups.
Conclusion Better alignment and similarity of good
clinical results at mid-term follow up may provide patients
who receive navigation TKA with long-term endurance of
their implants. Further studies on longer-term outcomes
and functional improvements are required to validate these
possibilities.
Level of evidence Prospective comparative study, Level
II.
Keywords Total knee arthroplasty Á Navigation Á Clinical
outcome Á Mid-term results Á Computer assisted surgery
Introduction
Total knee arthroplasty (TKA) is a well-established pro-
cedure that generally results in relief of pain, improved
physical function, and a high level of patient satisfaction.
TKA is conventionally performed with the use of intra-
medullary or extramedullary alignment guides and
achieves a high rate of success [20]. However, it has been
suggested that the most common cause of revision TKA is
the surgical error [23], resulting from malpositioning of the
components [5], which leads to poorer post-operative out-
comes [7]. Restoration of the coronal mechanical axis
within 3° is thought to be optimal for a better outcome.
However, the achievement of proper alignment is difficult,
and several authors have reported that 24–26% of con-
ventionally operated TKAs fail to achieve satisfactory
post-operative alignment, even when surgery is performed
by experienced surgeons [13, 19]. Based on the theoretical
assumption that the use of computer-assisted (CA) systems
in TKA may improve implant alignment and thus improve
implant longevity, the use of this technology is becoming
increasing popular.
A computed tomography (CT)-free navigation system
(Vector Vision; Depuy-BrainLAB, Heimstetten, Germany)
K. Ishida (&) Á N. Tsumura Á A. Kitagawa Á T. Chin Á T. Iguchi
Department of Orthopaedic Surgery,
Hyogo Rehabilitation Centre Center Hospital,
1070 Akebono-cho, Nishi-ku, Kobe 651-2181, Japan
e-mail: wavedreamer17@yahoo.co.jp
T. Matsumoto Á S. Kubo Á M. Kurosaka Á R. Kuroda
Department of Orthopaedic Surgery,
Kobe University Graduate School of Medicine,
7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
123
Knee Surg Sports Traumatol Arthrosc (2011) 19:1107–1112
DOI 10.1007/s00167-010-1361-4