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The debate on patellofemoral arthroplasty
(PFA) is becoming more intriguing as our
knowledge on the subject continues to grow.
The advantages of PFA above total knee
arthroplasty to address symptomatic isolated
patellofemoral osteoarthritis (PFOA) seem
obvious; PFA targets only the involved
(patellofemoral) compartment, sparing the
tibiofemoral cartilage, menisci, and cruciate
ligaments. Knee kinematics and propriocepsis
are better preserved which are strong arguments
favoring PFA above TKA for treating PFOA.
Skepticism is losing ground as more promising,
including long-term, PFA results appear [1-5]
and the results of total knee arthroplasty after
conversion are not negatively affected [6].
Despite these reassuring findings there are still
certain issues that need to be addressed.
Choosing the right patient and the right implant
is the hallmark to successful treatment of
PFOA. To date this remains difficult. The low
incidence of PFOA and PFA is the reason that
level l evidence on the subject is not, and is not
likely to become, available. Which makes
proving the many theories about PFA, for
example: “Do differences in etiology play a
role on PFA outcome?”, a big challenge. Also
declaring superiority of one PFA design over
another is skating on thin ice when it is not
backed up by a randomized controlled trial. On
top of that the low volumes of PFA does not
give every surgeon the chance of getting
familiar with the surgical procedure and the
many pitfalls of implantation of this technical
high demanding prosthesis. These issues:
choosing the implant, choosing the patient, the
role of etiology and the enhanced risk on
surgical error (and its consequences) need
answering. These answers ideally will have to
come from combined efforts of orthopedic
surgeons throughout the world who are playing
the field of patellofemoral pathology. In the
meantime we hope that this overview can
facilitate your future decision making on PFA.
Patient selection is crucial in PFA, especially
pre-existent femorotibial OA has a negative
effect on PFA succes rates. Symptomatic
isolated patellofemoral osteoarthritis is the
common indication for PFA. Although being a
distinct entity PFOA can act as a precursor of
generalized knee OA [22] making clear that
when considering PFA the surgeon must inform
the patient of the possibility of conversion to
TKA. In patients with knee osteoarthritis,
isolated patellofemoral joint osteoarthritis
occurs in approximately 4% to 24% of patients
[7-9]. Two retrospective case series noted that
isolated
patellofemoral
osteoarthritis
represented approximately 5% of patients
undergoing total knee replacement [10, 11].
Isolated patellofemoral osteoarthritis can be
considered a distinct entity from femorotibial
osteoarthritis. Systemic and local factors
influencing both the development and
maintenance of patellar cartilage differ from
those in the femorotibial joint [12]. In addition,
Patellofemoral
Arthroplasty
R.J. de Jong, H.P.W. van Jonbergen, A. van Kampen