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La rééducation est très progressive et le travail
des amplitudes articulaires en flexion est parti-
culièrement précautionneux et progressif étant
donné le délai de consolidation des baguettes
osseuses allongé en cas d’allogreffe. Des radio-
graphies successives permettent de surveiller
cette consolidation et d’autoriser une flexion
plus importante.
Cette allogreffe est donc la greffe de choix dans
notre expérience en cas de rupture chronique
de l’appareil extenseur après prothèse totale de
genou ; que cette rupture intéresse le tendon
rotulien ou le tendon quadricipital.
La rupture du tendon quadricipital avec rotule
très basse représente un cas particulier et la
technique dans ce cas sera adaptée. En effet, la
rétraction du tendon rotulien est telle que la ro-
tule devient un “obstacle” à la chirurgie. Nous
conseillons dans ce cas de procéder à une patel-
lectomie totale tout en conservant les fibres de
l’appareil extenseur et d’utiliser une allogreffe
massive avec un tendon rotulien complet, une
rotule entière légèrement désépaissie et un ten-
don quadricipital avec tendon du droit antérieur
complet.
Enfin, une alternative à l’allogreffe de l’appa-
reil extenseur serait la reconstruction ou le ren-
fort avec une bandelette de type Synthetic
Mesh. Cette technique est en cours d’évalua-
tion dans notre pratique.
Chronic rupture of the extensor mechanism
after total knee arthroplasty (TKA) is a
therapeutic challenge. In case of chronic
rupture of the patellar tendon, the existence of
a fibrous tissue, the quadriceps tendon
retraction and the appearance of a patella alta
do not allow a direct suture of the patellar
tendon with or without reinforcement. Inversely,
in case of chronic rupture of the quadriceps
tendon, the presence of a patella baja with
retraction of the patellar tendon does not allow
this suture. The healing would be achieved with
a poor functional outcome and an important
lack of flexion.
Furthermore, in these patients, should be consi
dered the patient’s age (often above 65 years),
apoor bone quality, asurgical history of the knee,
the presence of a patellar resurfacing, the
frequency of rheumatic diseases, osteoarthritis,
or pathology of the contralateral knee…
These multiple reasons make the extensor
mechanism allograft our first choice. There are
benefits as time saving and also absence of
iatrogenic lesions in the contralateral knee.
This is also useful in special circumstances
such as collagen disease, or a history of the
contralateral knee. If the quality of tissue may
appear worse than autograft, we must
emphasize the possibility of taking larger
grafts. The length of the patellar tendon and
patella of the allograft must be assessed to
obtain proper length and specific radiographs
are necessary (millimeter radiographs and
radiographs of the contralateral knee).
The surgical technique is very similar to that
described by Henri Dejour for autograft
reconstruction. The preparation of the allograft
is larger. The transplant uses complete extensor
mechanism with tibial tuberosity, patellar
tendon, patella and quadriceps tendon. The
patellar bone is wider and cut with concave
edges, allowing wider tendon harvest. Fixation
uses a wire on a flat head screw associated with
staples for the tibial tuberosity and metallic
wires for the patella. PDS reinforcement is
sutured distally throughout the extensor
mechanism, at 90° flexion. It protects the
allograft from constraints during flexion.
Rehabilitation is very progressive and range of
motion in flexion is particularly cautious and
progressive due to the time of consolidation of
an allograft. Successive radiographs assess the
consolidation and greater flexion will be
allowed.
In brief, allograft is the graft of choice in our
experience for chronic rupture of the extensor
mechanism after TKA, either patellar tendon
or quadriceps tendon ruptures.