الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
The patellofemoral joint is the third compartment of the knee joint lying
between the posterior surface of patella and the anterior surface of the
distal femur .The patella was classified anatomically into four types .
The patella has anterior ,posterior surfaces and a base which is thicker
superiorly giving attachment for quadriceps femoris muscle ,which have
four major components acting as dynamic stabilizers of the
patellofemoral joint ,they include vastus medialis, ,rectus femoris
muscle,vastus intermedius muscle,vastus lateralis, the distal part of the
vastus lateralis inserts onto the lateral patella obliquely thus providing
dynamic stabilization against medial displacement .The femoral trochlea
is the articular portion of the anterior surface of the distal femur, which
articulates with the patella. It consists of a sulcus with lateral and medial
facets. The quadriceps tendon it is tri-Laminar having the aponeurosis of
insertion of vastus lateralis lies sandwiched between that of vastus
intermedius and rectus femoris . The ligametum patellae continues from
the patella to the tuberosity of the tibia
The patella has important function as it increases the moment arm of the
quadriceps mechanism, provides a cartilage on cartilage articulation with
a relatively low coefficient of friction and centralizes the divergent forces
of the four heads of the quadriceps and transmitting these forces to the
patellar tendon.
It is important to understand the biomechanics of patellofemoral
joint,contact areas, contact pressure and reaction force to reach to the
aetiology and diagnosis.The pathology of the arthritis is duo to many Risk
factors and there are two main causes of osteoarthritis: Primary
patellofemoral arthritis and Secondary causes including patellofemoral
arthritis after trauma, secondary to malalignmet, secondary to Q angle
abnormality, following anterior cruciate reconstruction and duo to
systematic Factors such as sex hormones abnormalities, genetic
Susceptibility and racial differences.
The Normal cartilage has two main components, collagens (II,
IX, & XI) , proteoglycans (mainly aggrecan)and chondrocytes.
Disturbance in these components function cause osteoarthritis.
Patellofemoral Osteoarthritis can be diagnosed clinically by
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inspection, palpation and special examination and by radiology
as PXR ,CT and MRI.
Patellofemoral Osteoarthritis can be treated by non pharmacological
mearures as Psychosocial reassurance, weight
reduction ,temperature Modalities, exercise, orthotics and Bracing
,modification in activities of daily living and Pharmacological treatment
as topical agents and systemic agents as non-narcotic analgesics ,non
steroidal antiinflammatory drugs, narcotic analgesics, nutritional
supplements and intra-articular injection of steroids or hyaluronic acid
derivatives.
Surgical treatment :
The surgical treatment of patellofemoral arthrosis are divided
into two categories; For relieving the stresses on the joint and
improve the extensor mechanism asarthroscopic lateral retinacular
release, lateral Patellar facetectomy, proximal soft tissue realignment and
distal realignment procedures such as anterior or elevation osteotomy of
the tibial tubercle ,anterolatralization and anteromedialization of tibial
tubercle .And those Operation that directly address the pathology of the
articular cartilage include arthroscopic debridement, lavage and cortical
abalation, autologus Cartilage transplantation and at the last patellectomy.
Patellofemoral arthroplasty as a treatment of arthritis in late and extensive
stages is indicated in Degenerative or posttraumatic osteoarthritis limited
to the patellofemoral joint .
Severe symptoms affecting daily activities, failure of a previous surgical
procedure to unload the extensor patellofemoral malalignment .
Arthroplasty is contraindicated in: Patella baja (infera), Patella alta,
algodystrophy, regional pain syndrome, axis malalignment, fixed flexion
deformity and Early chondral disease.
Patellofemoral arthroplasty is a relatively new procedure with a legacy
that dates back to 1955. Patellofemoral arthroplasty is an option for the
treatment of patellofemoral disease arthrosis from primary osteoarthrosis,
dysplasia, or posttraumatic arthritis in patients often younger than age 60
years who have normal patellofemoral alignment.
Sparing of the tibiofemoral compartments, menisci, and cruciate
ligaments allows preservation of a more kinematically sound knee joint
than is typical with TKA, making it an attractive alternative to TKA or
patellectomy in this patient cohort. Conversion to TKA is likely to be the
salvage procedure after failed arthroplasty; thus, careful patient selection
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is important. Patellar maltracking from malalignment may result in early
failure, underscoring the need to exclude patients with uncorrectable
patellar instability or malalignment. The patient who has had a prior distal
realignment procedure may be a candidate for the procedure.
Contemporary designs are associated with reduced incidence
of patellofemoral complications, with progressive tibiofemoral arthritis
likely representing the primary failure mechanism of these newer
implants. Although patellofemoral arthroplasty may have a great value
for selected patients, it is important to recognize that most published
series have been short or midterm analysis of the procedure. Long-term
data, suggest that loosening of cemented trochlear and polyethylene
patellar components is uncommon. Further investigation is necessary to
determine how these implants will perform over 10 to 20 years and
whether younger patients can anticipate long-term success with this
procedure using newer prosthesis designs. Long-term failures from
tibiofemoral degeneration will occur in at least 25% of patients.
patellofemoral arthroplasty should be considered an intermediate
procedure for some patients with isolated patellofemoral arthritis when
TKA is not desirable.
custom patellofemoral arthroplasty appears to be a safe and effective
treatment for isolated patellofemoral arthritis of the knee.