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Fixation inJoint Arthroplasty
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MichaelMorlock, SarahFischer, andElkeLieb
Contents
13.1 Clinical History – 138
13.2 Clinical Outcome – 139
13.3 Fixation Method – 139
13.3.1 Cement Type – 140
13.3.2
Cementing Technique – 140
13.4 What Have WeLearned? – 141
References – 141
137
13
© The Author(s), under exclusive license to Springer-Verlag GmbH, DE, part of Springer Nature 2022
E. Hansen, K.-D. Kühn (eds.), Essentials of Cemented Knee Arthroplasty,
https://doi.org/10.1007/978-3-662-63113-3_13
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138
M. Morlock et al.
13.1 Clinical History
The clinical history of total joint arthroplasty (TJA)
started with implants xed into the bone without
cement. First pioneers in orthopedics concentrated
rather on innovative prosthesis designs imitating the
mechanical functions of natural joints than on their
xation method into the surrounding bone bed. In total
hip arthroplasty (THA) milestone developments in
implant xation were introduced in the mid-nineteenth
century by Judet with his articial femoral head (Judet
and Judet 1950), the Matchett Brown hemiarthroplasty
(Emery and Gray 1996), and the Phillip Wiles design of
a metal-on-metal prosthesis (Gomez and Morcuende
2005). Some impressively good long-term results exist
for these prostheses. For example, for a Judet polymethylmethacrylate (PMMA) hip hemiprosthesisa time in
situ of 51 years before revision was reported
Fig.13.1). This makes it the rst implant to have sur-
(.
vived for longer than 50 years. No signs of aggressive
osteolysis were found on histologic analysis, which conrms good tissue tolerance for PMMA (Kovač et al.
2004). In 1890, already the outstanding work from
Themistocles Gluck about mechanical principles has led
to an important understanding of total knee arthroplasty (TKA) prosthesis designs, which came into clinical use quite sometime after the THA designs
(Eynon-Lewis etal. 1992).
Based on these early biomechanical insights, it was
Sir John Charnley who marked one of the crucial milestones in orthopedics with his “low friction” arthroplasty concept that prevented mechanical loosening and
was associated with less wear debris due to a small head
diameter of 22.225mm (. Fig.13.2) (Charnley 2012).
The area of tribology research was born. For the xation of his implant, he utilized an acrylate bone cement
that was in surgical use for cranioplasty, which he modied in terms of adequate working time and the addition
of a radio-opaque agent. He described the property of
. Fig. 13.2 The Charnley monoblock prosthesiswith a small head
(diameter 22.225mm) and a Charnley Ogee PE Cup
this bone cement as a grout and not as a glue, highlighting that it acts as a space-ller holding the implant
against the bone due to its bounding to the adjacent surfaces by penetrating cavities and closely molding the
surface asperities. This xation method solved the initial
problem for the mechanical stability of the prosthesis in
the bone.
PMMA bone cement for TJA xation was launched
as a medical device. Initially, PMMA bone cement did
not contain any antibiotics. At the same time, Buchholz
and Engelbrecht were the rst to introduce the concept
of antibiotic-loaded bone cement (ALBC) in their
cemented hip procedures by mixing gentamicin powder
into their Palacos® bone cement (Buchholz and
Engelbrecht 1970). The antibiotic powder was mixed
into the cement rst by hand without really knowing the
right dosage and the release properties. This made it difcult to achieve an optimized combination aligned with
the patient-specic systemic antibiotic therapy. Despite
these shortcomings during the initial 10years, an overall
77% success rate in controlling infections could be demonstrated by this use of ALBC in 583 patients and a
90% success rate after subsequent revisions (Buchholz
etal. 1981). In the coming years, improvements in clinical success rates continued to rise with the market access
of industrially mixed and certied off-the-shelf ALBC.
. Fig. 13.1 Example of a Judet prosthesisexplant, revised at AK
Eilbek in Hamburg after 27years in situ
> Today, there is some evidence that ALBC signicantly
reduces the rate of infections in revision procedures
(Kleppel etal. 2017; Leong etal. 2020).
Fixation philosophies in TJA, nowadays, vary not only
greatly between countries (in Europe there is the phrase:
The further you go south the less cement in THA) but
also between different joints like hip, knee, shoulder, and
ankle. In 2019, the German Arthroplasty
Registry(EPRD) reported primary THA xation methods: 78.6% for cementless, 5% for cemented, and 14.8%
for hybrid cemented cases, whereas only 1.3% reversehybrid cemented implantations occurred. For TKA primary interventions, the situation was the opposite:
Cemented implantations are dominant with 93.2% and
Fixation inJoint Arthroplasty
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only 1.2% for cementless xations. Hybrid and reversehybrid cement xation was reported in only about 5% of
the cases (Endoprothesenregister Deutschland (EPRD)
2019). For the same year, the Swedish Knee Arthro-
plasty Register reported very similar data with only
7.3% cementless TKA surgeries. Between 1985 and
1995, Swedish surgeons experimented with cementless
and hybrid xations but came back to mainly all
cemented implants soon after (Swedish Knee Arthroplasty Register 2019).
13.2 Clinical Outcome
> In all available national registries, the most frequent
reason for revision is loosening of the prosthesis in
the surrounding bone bed in both THA and TKA
with 34% and 32% of all respective revision cases. The
second reason is diagnosed infection with 19% for
THA and 22% for TKA.
The EPRD reported loosening in 34% and infection in
19% of THA cases as a reason for revision and for TKA
revision 32% loosening and 22% infection. Notable is that
the national joint registries from Scandinavia, existing
since the early 1970s—thus with the most matured data—
expressed their doubts if the true incidence of infection is
underestimated by about 40% (Gundtoft etal. 2015; Jämsen etal. 2009; Espehaug etal. 2006; Witso 2015).
139
Patient Weight
z
Another factor that inuences signicantly the longterm survival of a joint implant is the patient’s body
mass index (BMI). Studies show, for instance in TKA,
that the adjusted cumulative hazard of revision due to
aseptic tibial loosening more than doubles when BMI
passes more than 35 kg/m2 (Abdel et al. 2015).
Interestingly, some newer studies indicate that uncemented TKA in the obese and morbidly obese might be
performing equal or better (Sinicrope etal. 2019). Again,
such results are strongly inuenced by the respective surgeon. In THA, body weight also comprises an important issue but the results are not coherent: Some
publications quote a quite signicant increase in complications with increased bodyweight; others do not
(Haynes etal. 2017).
Prosthesis Design
z
Since the introduction of the Swedish Hip Arthroplasty
Registry 40years ago, the choice of prosthesis design has
become less and less important. This does not mean that
the prosthesis design is not important anymore, but
rather that all registries and institutions (e.g., the
Orthopaedic Data Evaluation Panel) together, have been
very effective in identifying poor designs or materials and
consequently removing them from the market. This statement accounts for cemented and for uncemented prostheses.
13
> The clinical outcome of TJA depends on multiple factors.
Of all the factors responsible for the clinical outcome of
TJA, the most important factor cannot be assessed
directly: the implantation process performed by the
operating surgeon. The inuence of other factors can be
assessed by comparing patient cohorts, even so a surgeon bias cannot be completely ruled out.
Fixation Method and Patient Age
z
Registries have started early in their development to
report their data in addition to the whole data set separately for different age groups since age has a major
inuence. Most of the data show that THA patients
younger than 75 years generally benet more from
cementless xation, especially when considered on longterm follow-up. However, a signicantly better and longer clinical success result is achieved with cementing
xation for patients older than 75 years
(Endoprothesenregister Deutschland (EPRD) 2019). In
TKA, the inuence of age for the comparison between
cemented and cementless xation of the femur component in young patients does not show a signicant difference with respect to function or revision rate
(Franceschetti etal. 2017).
13.3 Fixation Method
> Uncemented and cemented designs are similarly suc-
cessful in most registries with national differences
with respect to preferred choices (Deere etal. 2019a;
Deere etal. 2019b).
A recent analysis of a National Joint Registry comes to
the conclusion that despite improved survivorship of
uncemented xation in TKA for osteoarthritis, cemented
xation remains the gold standard (Nugent etal. 2019).
Several clinical studies are available, either demonstrating the advantage of certain designs or showing similarities. Clinical studies always have to be viewed under
the limitation that surgeon inuence might be a major
factor for the results. As an example, just a single study
comparing 200 cases of a cementless tibial mobilebearing TKA design showing similar survival rates after
11years compared with cemented similar tibial design is
mentioned (Prudhon and Verdier 2017). Own TKA
autopsy study demonstrated that the xation strength
of cemented designs decreases with time in situ and
showed that cement pockets for increased cement bonding are advantageous (Gebert de Uhlenbrock et al.
2012). Again the age-related factor inuences the long-
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M. Morlock et al.
term result hypothesizing that younger patients are more
active and that the load factor does play a negative role
for the bony interface loading.
13.3.1 Cement Type
There are many different cements from several compa-
nies available (. Fig. 13.3). The handling differences
mainly concern viscosity (low, medium, or normal,
high). Depending on the cement type, work timings are
different and penetration and interdigitation into the
bone also vary with the application method (Kelly etal.
2018; Silverman etal. 2014). This makes it difcult for
surgeons since they have to adapt to their respective
cementing techniques depending on the kind of cement
they use. A data summary from the National Joint
Registry (NJR) concluded for cement type when
extracted for brand name with endpoint as cemented
component revision that Palacos® bone cement from
Heraeus Medical resulted in a signicantly lower cumulative revision rate after 12years than all other cement
brands (National Joint Registry 2020). Other registries
indicate that the introduction of new bone cements led
to survival rates as good as with “the old” bone cements
(Birkeland etal. 2016), but that not all bone cements
perform equally well (Trela-Larsen etal. 2017).
13.3.2 Cementing Technique
The introduction of innovative minimally invasive surgery (MIS) in 2016 represented a challenge for the correct cementing technique due to minimized access to
the bone site. The unilateral knee arthroplasty design
(UKA) introduced in parallel to MIS experienced early
failure rates assumingly also linked to the limited
access to the surgical site exposure which could result
in poor or non-homogenous cement penetration into
the bone (Hauptmann etal. 2008). Another complication associated with early failure could be posterior
cement leakage when the implanted prosthesis was
moved before the cement had hardened completely
(Karataglis etal. 2012). This started discussions regarding the questions such as which patient is best for which
prosthesis design (mobile or xed bearing, constraint
or unconstraint), which modern surgical technique
(minimal invasive or computer-assisted), and which
xation technique is most suitable (cemented, uncemented, or special coatings). A multitude of studies
performed at the University of Technology in Hamburg
highlighted that preparation of the bone bed is one of
the most crucial aspects for the xation strength of
TKA components (Nagel et al. 2017; Schlegel et al.
2015; Schlegel etal. 2014a; Schlegel etal. 2014; Schlegel
etal. 2011).
13
. Fig. 13.3 Examples for different cement types available
Fixation inJoint Arthroplasty
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. Fig. 13.4 Jet lavage as an effective way to improve cement-to-
bone xation strength
> The use of jet lavage seems to be a simple but very
effective way of improving the interdigitation and
strength of the initial cement–implant bond
(.
Fig.13.4).
141
13
(Puliero etal. 2019; Deere etal. 2019b). Future research
should focus on standardizing patient satisfaction
reporting and dening ways to optimize patient satisfaction after TKA (Kahlenberg etal. 2018b) and the implementation of patient-reported outcome measures
(PROMs) into national and even international common
registries.
The nal challenge to be solved is what Justin Cobb
from Imperial College in London calls “epistemology—
patient welfare and function versus Device survival”. A
revision or addition surgery might very well be justied
and not collectively called a “failure”, if every stage of
the process has produced the desired outcome. UKA
is a good example of this: The design with quite high
overall revision rates in the registries performs very well
if implanted by high-volume surgeons and can show
better function than TKA (Endoprothesenregister
Deutschland (EPRD) 2019; Deere et al. 2019a;
Mohammad etal. 2018; Casper etal. 2019).
> The focus on further improving the cementing tech-
nique for cemented TJA and on improving the pri-
mary stability for uncemented TJA will prevail.
Applying pressure to cement also improves the xation
strength (Pérez-Mañanes etal. 2011).
13.4 What Have WeLearned?
TJA has become a very successful procedure; it should
be considered as the operation of the century (Learmonth
et al. 2007), especially in THA. In the past, improvements in outcomes were made possible by improvements
in implant design and materials. As in other highly specialized performing elds, further improvement relying
only on improvement of the “hardware” will hardly be
possible anymore.
> “Big Data” available from the registries highlight
more and more the dominating importance of the
implantation process and the surgeon. The concentration on these factors will mark the twenty-rst century.
Especially in TKA, surgeons still face a group of
unhappy patients postoperatively despite the fact the
surgery went well and the positioning of the implant
was achieved as planned (Kahlenberg etal. 2018a; Klem
etal. 2020). Up to one out of four patients is unhappy
with the outcome of the TKA surgery after the rehab
phase, which is in contrast to THA surgery, for which
“the forgotten joint” is achieved in more than 90% of
the patients (Puliero etal. 2019). It’s paradoxical, that
despite the higher percentage of unhappy patients, revision rates in TKA after 10years are lower than in THA
Take-Home Messages
5 Fixation in total joint replacement has been
greatly improved by improvement in design and
materials over the last 50years.
5 Patient and surgical factors play an important
role in long-term survival.
5 Further improvement is only possible if all rele-
vant factors are addressed: material, design, surgeon, and patient.
5 Uncemented and cemented xations perform
equally well but benets of one method over the
other exist in certain patient cohorts.
5 In cemented xation, the preparation of the
bone bed is crucial and the use of jet lavage is
highly advised, especially in TKA.
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Bishop NE (2012) Inuence of time in-situ and implant type on
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Medial Unicompartmental
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Knee Arthroplasty
AsimKhan andFaresHaddad
Contents
14.1 Introduction – 144
14.2 Patient Selection – 144
14.3 Implant Development – 146
14.4 Implant Design – 147
14.5
Surgical Technique – 150
143
14
14.6 New Technology inUKA – 151
14.7 Postoperative Rehabilitation – 151
References – 152
© The Author(s), under exclusive license to Springer-Verlag GmbH, DE, part of Springer Nature 2022
E. Hansen, K.-D. Kühn (eds.), Essentials of Cemented Knee Arthroplasty,
https://doi.org/10.1007/978-3-662-63113-3_14
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A. Khan and F. Haddad
14
14.1 Introduction
Knee arthroplasty provides a predictable and reliable
way of treating painful loss of mobility of the knee joint
in patients with arthritis. There is a philosophical and
surgical debate as to whether osteoarthritis of the knee
can only affect individual compartments or whether the
whole knee is inevitably affected, either primarily or secondarily. The belief that arthritis is a disease of the
whole knee joint has led to a biased focus on improvements in total knee arthroplasty (TKA) design at the
expense of innovations in unicompartmental knee
arthroplasty (UKA; medial, lateral, or patellofemoral).
At the turn of the century, the introduction of minimally invasive techniques (Repicci and Eberle 1999)
resulted in renewed interest in UKA and its utilization
has increased at a rate nearly triple that of TKA (Foran
etal. 2013). Although the decision to undertake partial
or total knee arthroplasty may depend in part on a surgeon’s training, experience, or interpretation of literature, both partial and total knee arthroplasty are viable
options for the treatment of osteoarthritis of the knee.
The decision may ultimately be shaped by the ability of
enhanced technologies to help with the execution of the
procedure (Kayani etal. 2018a, b).
A recent synthesis of evidence from randomized trials, registries, and cohort studies suggested a shorter
hospital stay, fewer early complications, and better functional outcome with unicompartmental arthroplasty.
Following this procedure, patients can kneel better and
have better patient-reported outcomes. Mortality rates
may be reduced compared with TKA.The patients also
need fewer manipulations under anesthesia.
Revision surgery, however, is much more commonly
needed after unicompartmental versus total knee arthroplasty (NJR Online 2019). A higher perceived revision
rate has led to the UKA falling out of favor in some
centers and countries. While this should not be the only
key metric to assess an implant, there is potentially a
solution with the use of enhanced technologies that can
avoid malalignment and other risks associated with
UKA.
sion rate (Murray and Parkinson 2018). To add to the
confusion, because UKA is perceived as being a lesser
operation, some surgeons may be tempted to offer it to
patients with less severe osteoarthritis. Unfortunately,
this may lead to worse outcomes that may further tarnish the reputation of this procedure (Murray and Parkinson 2018). We must also recognize the potential for a
lower threshold for revising a “painful” partial knee
arthroplasty, as this is a relatively straightforward operation, whereas surgeons are less likely to advise revision
of total knee arthroplasty for the same indication due to
its perceived technical difculty. In addition, because of
the presence of early degenerative changes and osteophytes in the non-resurfaced compartments in a patient
with a partial knee arthroplasty, a surgeon may more
easily justify revision, which may have a poor functional
outcome because the symptoms could have nothing to
do with the arthroplasty. This is akin to secondary resurfacing of the patella in a patient with a TKA and a nonresurfaced patella, which, of course, is a very
unpredictable operation. Comparison of revision rates
as the only way of assessing outcome is, therefore, dangerous and we must look beyond registry data to cohort
series, prospective studies, and other datasets to understand the pros and cons of UKA compared with TKA
(Murray and Parkinson 2018; Murray etal. 2017; Goodfellow etal. 2010).
The communication of ndings can only be effective
if all authors refer to the same operation by the same
name. Terms such as unicompartmental, unicondylar,
bicondylar, and bicompartmental need to be dened
and standardized so that readers of research articles can
truly understand what is being referred to. More importantly, international registries need to agree on one
nomenclature so that long-term results can be accurately
understood and compared. Garner et al. (2019) proposed a simple classication system for combined partial knee arthroplasty in an attempt to address issues of
nomenclature. There will doubtless be differing views
within the orthopedic community, but the simplicity of
the proposed classication system should enhance its
widespread adoption, or at least the adoption of a modication that will be acceptable to all.
> In simple terms, hitting a target through a minimally
invasive incision and with high accuracy because of
the sensitivity and balance of the rest of the joint
demands better instruments or enhanced technologies that are now available (Kayani etal. 2018a).
Authors from centers that perform high volumes of partial knee arthroplasty assert that for optimal outcomes,
a surgeon’s proportion of unicompartmental arthroplasty ought to be more than 20% to minimize the one
disadvantage of this operation, namely its higher revi-
14.2 Patient Selection
Patient selection for UKA has remained a heavily
debated topic in the literature.
> The ideal candidate for UKA is the symptomatic, uni-
compartmental osteoarthritic patient with an intact
ACL, preserved range of motion, a correctable defor-
mity, no inammatory arthritis, and an intact medial
collateral ligament (MCL).
Medial Unicompartmental Knee Arthroplasty
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. Fig. 14.1 Weight-bearing posteroanterior radiographs in extension (left) and exion Rosenberg views (right)
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We have moved on from the initial Kozinn and Scott’s
criteria, which recommended against UKA in patients
who were under the following categories:
5 Younger than 60years of age.
5 Weighed more than 82kg.
5 Extremely active or heavy laborers.
5 Had chondrocalcinosis or exposed bone in the patel-
lofemoral joint (PFJ) because of an early risk of failure (Kozinn etal. 1989; Kozinn and Scott 1989).
Pandit etal. have shown similar or better clinical outcomes with mobile-bearing UKA in patients with the
potential contraindications proposed by Kozinn and
Scott (Pandit etal. 2011). Furthermore, work by Scott
and Goodfellow etal. challenged the thresholds previously reported and showed that weight, age, activity, the
state of the PFJ, and chondrocalcinosis should not be
considered contraindications to UKA (Deshmukh and
Scott 2001; Scott 2003; Goodfellow 2006).
Special preoperative weight-bearing X-rays can be
extremely useful. Standing PA views in extension and
exion (Rosenberg views) can be used to screen for unicompartmental disease (.
X-rays will reveal the pattern of wear; posterior tibial
bone loss indicates a disrupted or non-functional ACL
(. Fig. 14.2). Anterior tibial translation in ACLdecient knees exposes the posterior tibia to contact
stresses from the distal femoral condyles. Merchant or
skyline views may demonstrate PFJ arthritis which is a
relative contraindication to UKA.
Intraoperative assessment of unicompartmental disease can be made at the time of surgery with the option
to proceed with TKA if there is signicant lateral or
patellofemoral compartment wear. Mild softening or
Fig. 14.1). Standing lateral
ssuring of cartilage in the lateral compartment can be
accepted. Konan et al. have shown that medial PFJ
chondral lesions do not appear to affect outcomes after
UKA; however signicant (modied Outerbridge grade
3 or higher) lesions in the central or lateral PFJ are an
indication to proceed with TKA (Konan and Haddad
2016). ACL deciency is considered a signicant (yet
not absolute) contraindication to UKA.If the tibial plateau wear pattern is central or anterior, a xed-bearing
UKA may still be feasible and mobile-bearing implants
should be avoided. Little or no posterior slope should be
applied. The surgeon should bear in mind that lateral
subluxation of the tibia may still lead to contralateral
compartment arthritis. As varus osteoarthritis progresses, it may present with a kissing lesion or an “anvil
osteophyte”. The former results from central tibial subluxation. The lateral tibial spine erodes the medial aspect
of the lateral femoral condyle producing a chondral
lesion. A lesion of signicant size warrants a total or
bicompartmental knee replacement. The anvil osteophyte is a tibial osteophyte that occurs just anterior to
the footprint of the ACL and causes notch impingement. The resultant exion contracture can be corrected
on the removal of this osteophyte. Inammatory arthritis in the form of a signicant synovial reaction or diffuse chondrocalcinosis, as seen in gout or pseudogout,
particularly involving hyaline cartilage as opposed to
the menisci alone, are considered contraindications to
UKA.
Although osteoarthritis limited to a single compartment of the knee is the most common indication for
UKA, focal spontaneous osteonecrosis of the knee
(SPONK) with articular surface collapse may be another
indication. Osteonecrosis of the medial femoral condyle
and rarely of the medial tibial plateau has anatomical
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A. Khan and F. Haddad
14
. Fig. 14.2 Lateral weight-bearing views of both knees (left) of the patient in . Fig.14.1 showing a central pattern of wear in both knees.
In contrast, standing lateral X-rays of a patient with posterior tibial bone loss (right) indicating ACL deciency
features very similar to those of osteoarthritis and the
surgical technique for UKA is very similar to that used
for patients with medial osteoarthritis lesions (Radke
etal. 2005).
lateral compartments of the knee while preserving the
cruciate ligaments (Gunston 1971). Modular designs
such as the St. Georg Sled (1969), the Manchester knee
(1971), the Marmor (1972), the Liverpool knee (1972),
and Insall’s Unicondylar knee (1976) were all developed
> A deep femoral defect secondary to SPONK has to be
dealt with carefully to ensure that not too much bone
is milled off the femur and cemented techniques
should be utilized whenever possible (Radke et al.
2005).
during a short period of time as interest in UKA was
revived. The materials used in the development of these
implants evolved over time and initial results were disappointing perhaps because of the learning curve associated with the introduction of a new technique.
The Oxford UKA designed by Goodfellow and
A meta-analysis of 273 patients undergoing UKA
instead of TKA for SPONK has shown fewer complications, signicant improvements in functional outcomes,
and 95% survivorship at a mean follow-up of 6 years
(Jauregui etal. 2018).
O’Connor and rst used clinically in 1982 (Phase 1,
. Fig.14.3) was perhaps the most signicant evolution
in UKA design (Goodfellow and O’Connor 1978).
Earlier designs had utilized a polyradial, convex metal
femoral component based on the natural polycentric
form of the femoral condyles. This is articulated with a
non- conrming at or slightly concave polyethylene
14.3 Implant Development
tibial component. The rounded femoral component
articulating with a at tibia led to the reduced contact
UKA has the advantage of being anatomic by design;
preservation of both cruciate ligaments and restoration
of the native tension in the collateral ligaments results in
the reproduction of near-normal kinematics of the knee
(Patil etal. 2005).
One of the earliest UKA designs, the polycentric,
was developed in 1968 by Frank Guston, a Canadian
surgeon, while on a fellowship at Wrightington Hospital
in the UK. It involved replacing both the medial and
area and, therefore, increased contact pressures particularly in deep exion where the radius of the posterior
part of the femoral component was smaller. Designers
of the Oxford UKA wanted to maximize the contact
area between the two components of the prosthesis
while allowing for the natural translation and axial rotation that occurs in the native knee during exion and
extension activities (Goodfellow and O’Connor 1978).
The Oxford UKA was therefore designed with two
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