Knee Surgery, Sports Traumatology, Arthroscopy
No diﬀerence in mid-term survival and clinical outcome
between patient-speciﬁc and conventional instrumented total knee
arthroplasty: a randomized controlled trial
M. G. M. Schotanus
· B. Boonen
· W. van der Weegen
· H. Hoekstra
· R. van Drumpt
· R. Borghans
· R. Vos
L. van Rhijn
· N. P. Kort
Received: 22 December 2017 / Accepted: 27 April 2018
© European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2018
Purpose The purpose of this multicentre prospective randomized controlled trial was to compare the survival rate and clinical
outcome in total knee arthroplasty (TKA) after MRI-based patient-speciﬁc instruments (PSI) and conventional instruments
5 years after initial surgery.
Methods At a mean follow-up of 5.1 years (0.4), 163 patients (90.6%) with a mean age of 71.8 years (8.7) were analysed. A
survival analysis with revision of the TKA as endpoint was performed. The Knee Society Score (KSS), evaluations on plain
radiographs and patient-reported outcome measures (PROMs) were obtained preoperatively and at each FU.
Results At ﬁnal follow-up, one TKA in the PSI- (1.2%) and 3 TKAs in the conventional group (3.8%) had undergone revi-
sion surgery (n.s.). No radiological abnormalities were noted at any time point. Postoperatively, the KSS and PROMs sig-
niﬁcantly improved within each group compared with the preoperative values. There were no clinically relevant diﬀerences
for the KSS [PSI: 77.4, 9.8 (95% CI 75.0–79.7) vs. conventional: 77.3 10.5 (95% CI 74.9–79.8)] and the PROMs between
both groups (n.s.) at 5 years follow-up.
Conclusion There is still a lack of reliable data on the survival of TKA and clinical evidence, when using PSI for TKA.
Longer follow-up studies are, therefore, needed.
Level of evidence I.
Keywords Patient-speciﬁc instruments · Conventional instruments · Total knee arthroplasty · Mid-term · Survival ·
Randomized controlled trial · PROMS · TKA · RCT · PSI
One of the key factors that can improve the longevity of the
implant after total knee arthoplasty (TKA) is a correct align-
ment of the individual femoral and tibial components [2,
11, 19, 22]. Malalignment is associated with poor implant
survivorship [19, 23, 24, 29]. Alignment of the TKA can be
done in several ways. During the conventional technique, the
TKA position is deﬁned during surgery with use of align-
ment rods. Several studies reported results of postoperative
malalignment using conventional alignment rods in TKA
[6, 14, 28]. Patient-speciﬁc instruments (PSI) are already
in relatively common use to align the TKA. The method of
image acquisition and preoperative planning is not stand-
ardized among different manufacturers . Published
results on PSI are contradictory. PSI’s early 2 years clinical
results are equal to conventional instrumented TKA [5, 27,
36]. There is still a lack of reliable data on the survival of
TKA and long-term clinical outcome with the use of PSI.
To our knowledge, there are no randomized controlled tri-
als (RCT) comparing the implant survival and clinical out-
come between PSI TKA and conventional TKA at 5-year
This multicentre RCT is a continuation of previously
published studies that compared intra-operative results,
the radiological outcome of the component alignment and
the short-term clinical follow-up in 180 patients who were
The original version of this article was revised: one of the
co-author’s (W. van der Weegen) middle name has been included.
* M. G. M. Schotanus
Extended author information available on the last page of the article