2. Medial Parapatellar Approach
• Room setup and equipment
• standard OR table
•
Patient positioning
• supine position
• bump under the operative hip to minimize hip external
rotation if needed (goal is to have patella facing
straight up)
• Thigh tourniquet should be placed as proximal as
possible to allow adequate room for prepping and
draping (ideally placed in hip crease)
3. Medial Parapatellar Approach
• Draw incision and
identify anatomy
• identify tibial tubercle,
patella,
• draw a straight midline
incision starting several
centimeters (generally
four finger breadths)
proximal to the proximal
pole of the patella and
continuing just distal to
the tibial tubercle
4. Medial Parapatellar Approach
• Incise to extensor
mechanism
carry the skin incision
straight down to the
deep fascia which
marks the extensor
mechanism (quad
tendon, patella, and
patellar ligament)
5. Medial Parapatellar Approach
• Create skin flaps
• elevate skin flaps just
deep to the fascia
the perforating arteries
which supply the skin
run just superficial to
the deep fascia
6. Medial Parapatellar Approach
• Identify medial aspect
of patellar tendon and
quadriceps tendon
• identify the medial
aspect of the patellar
ligament, medial aspect
of the patella and the
quad tendon lateral to
the vastus medialis
oblique (VMO).
7. Medial Parapatellar Approach
• Perform arthrotomy
• start from the proximal
aspect in a longitudinal
manner curving medially
around the patella,
• leave 3-5 mm of soft tissue
on the patella to assist with
arthrotomy closure later in
the case
• complete the arthrotomy by
a straight distal cut along
the medial border of the
patellar ligament
8. Medial Parapatellar Approach
• Perform proximal tibia soft
tissue release
• sharply dissect enough of
the medial capsular sleeve
off of the tibia to provide
exposure of the joint
• the amount of dissection is
variable, depending on the
particular knee, but a good
rule of thumb is to dissect
the tibia posteriorly to the
mid-coronal plane
9. • Flex knee, evert patella, and prepare
joint space
• flex the knee to at least 90 degrees
and evert the patella
• resect fat pad, ACL remnant&
meniscus
place retractors
• a lateral retractor is then placed
under the lateral meniscus near the
mid-coronal plane
• a medial retractor retracts the medial
sleeve
• posterior retractor (PCL or Hohmann
style) is placed in front to the PCL to
push the tibia anteriorly
10. Medial Parapatellar Approach
• Advantages
– familiar to most
– excellent exposure even in
challenging cases
• Disadvantages
– failure of medial capsular
repair
– lateral patellar subluxation
– access to lateral
retinaculum less direct
– may jeopardize patellar
circulation if lateral release
is performed
11. Lateral Parapatellar Approach
• Advantages
– useful for a fixed valgus
deformity
– preserves blood supply to
patella
– prevents lateral patellar
subluxation
– direct access to lateral side in
a valgus knee
• Disadvantages
– technically demanding
• medial eversion of patella is
more difficult
– may require tibial tubercle
osteotomy
12. Midvastus
– similar approach to medial parapatellar that
spares VMO insertion and may lead to quicker
recovery
• Advantages
– vastus medialis insertion on quad tendon is
not disrupted
– potentially allows accelerated rehab due to
avoiding disruption of extensor mechanism
– patellar tracking may be improved compared
to medial parapatellar approach
• Disadvantages
– less extensile
– exposure difficult in obese patients
– exposure difficult with flexion contractures
• Relative contraindications
– ROM <80 degrees
– obese patient
– hypertrophic arthritis
– previous HTO
13. Subvastus Approach
•
– muscle belly of vastus medialis is lifted
off intermuscular septum
• Advantages
– patellar vascularity preserved
– extensor mechanism remains intact
– minimal need for lateral retinacular
release
• Disadvantages
– least extensile
– potential for denervation of VMO
• Relative contraindications
– revision TKA
– large quadriceps
– previous HTO
– obese patient
– previous parapatellar arthrotomy
14. Extensile Exposures
•
Quadriceps snip
– technique
• snip made at apex of quadriceps tendon obliquely across
tendon at a 45-degree angle into vastus lateralis
– advantages
• no change in post-operative protocol
• minimal, if any, long-term consequences
– disadvantages
• not as extensile as a turndown or tibial tubercle osteotomy
15. Extensile Exposures
• V-Y turndown
– technique
• straight medial parapatellar arthrotomy with diverging incision
down the vastus lateralis tendon towards lateral retinaculum
– advantages
• allows excellent exposure
• allows lengthening of quadriceps tendon
• preserves patellar tendon and tibial tubercle
– disadvantages
• extensor lag
• may affect quadriceps strength
• knee needs to be immobilized post-operatively
16. Extensile Exposures
• Tibial tubercle osteotomy
– technique
• 6-10 cm bone fragment cut from medial to lateral
• fixed with screws or wires
– advantages
• excellent exposure
• avoids extensor lag seen with V-Y turndown
• avoids quadriceps weakness
– disadvantages
• some surgeons immobilize or limit weight-bearing post-operatively
• tibial tubercle avulsion fracture
• non-union
• wound healing problems
