PATELLAR DISLOCATION is a common sport injury.usually neglected in majority of cases.

1. PATELLAR DISLOCATION
PRESENTED BY-DR NAVEEN RATHOR
RESIDENT DOCTOR
R.N.T. MEDICAL COLLEGE

2. ANATOMY
-patella is a largest sesamoid bone roughly triangular in shape, with the
apex of the patella facing downwards.The apex is the most inferior
(lowest) part of the patella. It is pointed , and gives attachmentto the
patellar ligament.
- function of patella :
• 1)primary function is to increase the force
production of the quadriceps; acts like a pulley to
increase the mechanical action of the quadriceps
• 2)centralizes the divergent muscles of the quadriceps
• 3)protects the femur
- Thus improving efficacy of quadriceps contraction
- HOW
- patella displaces the force vectors of quadriceps
and patellar tendons away from the centre of
rotation of knee

4. • In the patella an ossification centre develops
between the ages 3–6 years.[1] The patella
originates from two centres of ossification
which unite when fully formed.
DEVELOPMENT

5. PATELLA
The upper three-quarters of the patella articulates with the
femur and is subdivided into a medial and a lateral facet by
vertical ledge which varies in shape.

6. Wieberg classification
• Wieberg classify patella on the basis of size of
medial and lateral facets-
• Type1-equal medial and lateral facet
• Type2-medial facet is slightly smaller
• Type3-medial facet is markedly smaller

7. BLOOD SUPPLY
The patellar network (circulatory anastomosis ) is an
intricate network of vessels around and above the patella,
and on the contiguous ends of the femur and tibia, forming
a superficial and a deep plexus.

8. •
QUADRICEPS AND OTHER SOFT TISSUE STRUCTURE
• rectus femoris tendon: 8-10 cm in length, triangular in shape
with insertion 3-5 cm in width at superior pole patella
• VMO tendon: inserts obliquely at superomedial border of
patella,only a few mm in length; primary stabilizer of patella
medially against VL
• vastus lateralis: inserts obliquely at superolateral aspect of
patella, 2.8 cm in length
• lateral expansion of the vastus lateralis with a superficial and
deep layer forms the lateral retinaculum; deep layer is the
lateral patellofemoral lig: this is a static guide for the patella;
this may decrease medial excursion and increase lateral
tracking .
• medial side also has a PF lig, but it is much weaker than the
lateral side

10. PATELLOFEMORAL JOINT
The patellofemoral joint (PFJ) is a complex
structure with high functional and
biomechanical requirements.
The normal function of this joint is dependent
on the congruent relationship of the patella
with the trochlear groove.

11. ARTICULATION
• no contact between the femur and patella in full
extension;
• from extension to flexion, the patella: begins laterally
and moves medially as the patella enters the trochlear
groove and the tibia derotates;
• with flexion, patella enters the trochlear groove from
the lateral side
• seats in the trochlea at ~20 degrees; at this point, the
congruence and compressive forces provide stability
• from 0-20 degrees, stability comes from soft tissues

12. PATELLOFEMORAL CONTACT POINTS
Variations in area of contact:
inf. Surface – first contacts – 20 ⁰ flexion
Mid-portion – 60 ⁰ flexion
Superior portion – 90 ⁰ flexion
Extreme flexion( > 120 ⁰ ) – only medially &
laterally , quadriceps tendon articulates
with trochlea

13. Patellofemoral Biomechanics
• Joint Reactive Force
– In flexion, patella compressed
onto femur creating joint
reactive force
-directly related to quadriceps
force generation
-increases as the angle of
flexion increases
– Stair climbing – 3.5 X BW
– Deep bends – 7-8 X BW

14. The length of the lever arm varies as a function of :
• Geometry of trochlea
• Varying patellofemoral contact areas
• Varying center of rotation of knee (flexion)

15. PFJ BIOMECHANICS
Patellofemoral joint reaction force
WALKING 0.5xBW
STRAIGHT LEG RAISE 0.5xBW 0 DEG
CYCLING: 1.2 × BW
RISING FROM A CHAIR w ARMS: <3 × BW
STAIRS (UP OR DOWN) 3.3xBW 60 DEG
JOGGING & SQUAT–RISE 6xBW at 140 deg
SQUAT–DESCENT 7.6x BW at 140 deg
JUMPING UP TO 12 × BW
Ff
Ft
Fj
PostGrad Orth Deiary Kader

16. PATELLO FEMORAL INSTABILITY
Static stabilizers
1. trochlear groove : primary bony stabilizers:
depth, height
patellar engagement
2 medial patello femoral ligament (MPFL):
primary static soft tissue stabilizer
3 Medial retinaculam
Dynamic stabilizer
quadriceps (VMO)

17. CAUSES OF PATELLA INSTABILITY
• Soft Tissue Restraints
• Medial
• MPFL Insufficiency
• VMO dysplasia/VL dominance
• Lateral -- ITB, Contracture Lat Ret
• Osseous abnormalities
• Patella alta/ morphology
• Trochlea dysplasia
• Lower limb Malalignment (Torsion or Genu Valgum)
– Fem anteversion, Ext tibia torsion, foot pronation
– Increased Q angle or TT:TG distance
• Gait (Valgus thrust, Pelvis core muscles)

18. • Direct injury-Rare cause
Knee flexed, quadriceps relaxed
>> patella forced laterally by direct force.
• Indirect injury-Common cause
in athelets
MECHANISM OF
INJURY
Sudden, severe contraction of quadriceps
muscle
While the knees is stretch in FLEXION
VALGUS & EXTERNAL ROTATION

19. Lateral patellar dislocation. (a) Drawing shows the
classic mechanism of injury: fixed tibia, internal femoral
rotation, and quadriceps contraction.

20. PATTERNS OF DISLOCATION
ACUTE DISLOCATION-
Single episode after a significant trauma.
Almost always lateral dislocation
RECURRENT DISLOCATION-
• repeated, occasional dislocation (commonest form).
• The dislocations may occur at intervals of weeks or
months.
HABITUAL DISLOCATION-
also known as chronic dislocation
• patella which dislocates every time the knee flexes.
• in these cases it cannot be held in the reduced
position throughout the full range of flexion. i

21. Recurrent Dislocation
• Second decade
• Female preponderance / Athletic males
• Initial episode of dislocation
• Subsequent episodes of instability
• Frequency decreases with Age(Crosby)
• The main factor is incompetance of MPFL

22. Habitual dislocation
• Knees in which patella dislocates laterally each
time knee is flexed and returns to midline in
extension(Habitual dislocation)
• More severe –patella permanently dislocated
–(Permanent dislocation)

23. PATELLO FEMORAL INSTABILITY
Who tends to recur
• Young
• Female
• Family history
• Bilateral
• Atraumatic disorders
• Anatomic abnormalities
patella alta
trohlear hypoplasia
↑TT-TG distance
↑ ‘q’ angle
quadriceps dysfunction
hyper mobility

24. PATELLO FEMORAL INSTABILITY
Evaluation
We evaluate the following features
1. Integrity of medial patello femoral ligament
2. Height of patella on physical and radiographic
examination
3. Length of patellar tendon
4. Position of patella in relationship to trochlea

25. Patella Alta
A patella alta, or high-riding patella, is a patella that is too high above
the trochlear fossa and occurs when the patellar tendon is too long.
Patella alta is considered a main factor in patellofemoral
misalignment because with patella alta, the degree of flexion needs
to be higher for the patella to engage in the trochlea, compared with
a normal knee.
This problem leads to reduced patellar contact area and decreased
bone stability in shallow degrees of flexion.
About 25% of the patients with acute patellar dislocation have a high-
riding patella depicted on MR images.
Note, however, that patella alta is a normal anatomic variant that is
asymptomatic in most individuals.

26. Blumensaat's line
NORMAL

27. TROCHLEAR DYSPLASIA
 The normal trochlea is located in the anterior aspect of the
distal femur. It is composed of two facets divided by the
trochlear sulcus
 The lateral facet is the biggest, it extends more proximally
than medial facet and is more protuberant in A.P. Aspect
 Dysplastic trochleas are shallow, flat or convex
 These trochleas are not effective in constraining mediolateral
patellar displacement
 Is defined by a sulcus angle > 140°
 Trochlear dysplasia has been identified as one of the main
factors contributing to chronic patellofemoral instability.

28. TROCHLEAR DYSPLASIA
Radiological features
X- ray lateral projection of normal trochlea will typically show the contour of
the facets, and posterior to them, the line representing the bottom of the
sulcus is visualized and is continues with the intercondylarnotch line

29. TROCHLEAR DYSPLASIA
Radiological features
Crossing sign
 The radiographic line of trochlear sulcus crosses the projection of the femoral
condyles
 The crossing point represents the exact location of the deepest point of trochlear
sulcus which is about 0.8mm posterior to a line projected from anterior femoral
cortex, in dysplastic trochlea it’s an point is 3.2mm forward to same

30. TROCHLEAR DYSPLASIA
Radiological features
Trochlear spur
the supratrochlear spur corresponds to an attempt to contain the lateral
displacement of the patella

31. TROCHLEAR DYSPLASIA
Radiological features
Double-contour sign
represents the hypo plastic medial facet, seen posterior to the lateral facet in
lateral view

32. TROCHLEAR DYSPLASIA
Classification of trochlear dysplasia
Type A: crossing sign +
the trochlea is shallower than normal, but still symmetrical and
concave
Type B: crossing sign +
supratrochlear spur +
the trochlea is flat or convex in axial view

33. TROCHLEAR DYSPLASIA
Classification of trochlear dysplasia
Type C: crossing sign +
double-contour sign +
supratrochlear spur –
representing hypoplasia of medial facet and lateral facet convex
Type D: crossing sign +
double-contour sign+
supratrochlear spur +
clear asymmetry of the height of facets, and referred to as a cliff pattern

34. Trochlear dyspla

35. Apprehension test of Fairbank
• Patella pushed laterally in 20-30 deg of
flexion

36. Patellar tilt( Kolowich & Poulos)
-in 20 degree knee flexion
-fingers are placed on medial side of patella and thumb on
lateral aspect.

37. Dynamic Patellar Tracking
• Examiner standing in front of seated
patient while the patient slowly extend
the knee.
• J sign- lateral subluxation as the knee
approches full extension.

38. Active patellar tracking
(lateral pull test)
• Should be examined with the knee relaxed in
the extended position.
• When the quadriceps muscle tightened
,motion of patella examined
• Normally,the patella should move more
superiorly then laterally

39. Described by sir brattstrom
firstly
an angle formed by the line of
pull of quadriceps
mechanism and that of
patellar tendon as they
intersect vat the centre of
patella.
for measurements patella
must be centre on trochlea
by flexing the knee 30
degree.
Q- Angle

40. Q angle
(described by sir Brattstrom)
Values vary-male 10-14 deg Female 17 deg
> 20 Abn
• Increase in-genu valgum,
external tibial torsion
increase femoral anteversion
• Increase Q angle more chance of
Recurrent subluxation

41. IMAGING OF THE PATELLOFEMORAL JOINT
AP and Lateral Knee x-ray
Axial view
Merchant’s view
MRI Axial view
CT Rotational Profile
Merchant’s

42. Blumensaat's line
NORMAL

43. Radiology- Insall Salvati Ratio
• T –Length of patellar tendon
• P-greatest diagonal length of
patella
• Average T/P=1.02 SD 0.13(Insall)
1.04SD0.11( Aglietti)
>1.2 Patella Alta,<0.8 Patella infera

44. MEASURING PATELLA HEIGHT
Caton – Deschamps index =0.6-1.3
Ratio between articular facet length of patella and distance
between articular facet of patella and anterior corner of
superior tibial epiphysis,knee flexed 30 degree.
Patella infra-<0.6
Patella alta>1.3
PostGrad Orth Deiary Kader

45. Blackburne-peel ratio
-length of articular surface of patella to length measured
from articular surfacevof tibia to inferior pole of patella.
-Measurement of patellar height
normal rangr =0.54-1.06

46. Distance from Tibial Tubercle to Trochlear Groove(TT-TG)
The position of the tibial tubercle is crucial for the inferolateral force
vector of the patella. In a normal joint, the tibial tuberosity lies
vertically under the femoral sulcus, directing the force vector inferiorly
during knee bending.
However, if there is excessive lateralization of the tibial tuberosity, the
patella is pulled laterally during flexion.
A tibial tubercle–trochlear groove distance of more than 20 mm is
nearly always associated with patellar instability. Values of 15–20 mm
are considered borderline, less than 15 mm is considered normal.
However, measurement of the lateral distance between the tibial
tubercle and the trochlear groove is less accurate in individuals with
severe trochlear dysplasia because no deepest point of the trochlea can
be defined.

47. Image shows a normal distance of 12 mm
between the tibial tubercle and the trochlear
groove.
Image shows a distance of 22 mm, which is
higher than the normal range

48. Trochlear Depth
• Dejour used a true lateral radiograph
with the knee in 20 degree flexion
To evaluath trochlear depth.
-trochlear depth was defined as the
maximum distance of the trochlear
groove from the line connecting the
medial and lateral trochlear facets.
< 5MMmm consider pathiological.

49. Axial views
• Various method have been described to taking
axial view.
• Knee flexed in range of 20-45 degree.
• Shape of patella should be evaluated ,along the
shape of the femoral trochlea and the
relationship of patella to femur.

50. MERCHANTS VIEW
• An xray of knee while it is in 30 degree
flexion,with the patellofemoral joint viewed
tangentially.
• Show the position of the dorsal surface of
patella as it sits in trochlear groove.
• Measurew sulcus angle and congruence angle

51. Merchants view: tangential axial view of patello femoral joint obtained with knee in 45°
of flexion
Sulcus angle
normal angle : 140°
> 140° : trochlear dysplasia
Congruence Angle
normal : -8°to+14°
>14° indicates lateral subluxation
Lateral Patello Femoral Angle
normal: angle opens laterally
abnormal : angle opens medially
or lines become parallel

52. Laurin’s view
• Lateral patellofemoral angle is measured
• Open laterally in normal knees
• Open medially or parallel in recurrent
dislocations

53. CT
• Significant advantage
– Avoids problems associated with positioning,obesity
etc
– Avoid image overlap and distortion
• Look for
– sulcus angle, tilt ,congruence and subluxation
• Reference line tangential to posterior condyles
more accurate

54. CT classification of malalignment
• Type 1 -Subluxed with out tilt
• Type 2-Subluxed with tilt
• Type 3 tilt without Sublux
• Type4 normal alignment

55. MRI SCAN
-MR imaging can be used to diagnose prior patellar
dislocation on the basis of typical injury patterns.
-In general, deformity or edema of the inferomedial
patella and the lateral condyle, in conjunction with MPFL
disruption and patellar lateralization, is diagnostic for
recent patellar dislocation.
- More than two-thirds of the patients will show chondral
or osteochondral lesions of the medial patella.

56. MPFL injury
Patella pain
Articular Damage
MRI SCAN

57. MANAGEMENT
CONSERVATIVESURGICAL

58. CONSERVATIVE MX
• Non Operative management To be attempted in all
patients.
• -Goals –Normal flexibility,Balanced quadriceps
strength,Stretching of tight lateral structures
 Push back w/o difficulty .
 Jt aspiration and immobilized in full extension for 3 weeks.
>Splint;
• If no sign of soft tissue lesion
• Retained for 2-3 weeks
• Quadriceps strengthening exercise ; 2-3 months.

59. TREATMENT OF PATELLA INSTABILITY
Conservative first
Quads strengthening
Core stability
McConnell Taping
Insoles

60. Quadriceps Training
• Most essential component
• Strengthening of quads esp. VMO
• Isometric and progressive resistive ex. with knee
in extension
• With increase in strength,Short arc exercises in
last 300.

61. McConnell patellar taping
• Indications
• With certain knee injuries – such as
patellofemoral pain syndrome where abnormal
patella tracking is contributing to the injury.
• To prevent injury or injury aggravation – Patella
taping may be beneficial during sports or
activities that place the knee (patellofemoral
joint) at risk of injury or injury aggravation.

62. McConnell Medial PatellaTaping
with the knee slightly bent, and rolled up towel under the knee.
Start the tape in line with the middle of the knee cap at the
outer aspect of the knee. gently push the knee cap towards
the inner aspect of the knee.whilst simultaneously using your
fingers to pull the skin at the inner aspect of the knee towards
the knee cap. Repeat this process 1 – 3 times depending on
the amount of support required.

63. BAREFOOT RUNNING
• Barefoot running may reduce patellofemoral joint
stress as a result of reduced joint reaction forces.
• Barefoot runners are more likely to use a forefoot
vs a heel strike pattern in the initial loading
response, which has been shown to increase ankle
eccentric work and simultaneously decrease the
loading on the knee joint.

64. SURGICAL TREATMENT
• Surgery in acute patellar dislocation indicated
in-
• 1)osteochondral fracture
• 2)loose body formation or joint incongruity
• 3)incompetancy of MPFL
• Removal of loose bodies and MPFL repair
required in these conditions.

65. • Recurrent dislocation
• Anterior knee pain
• Knee swelling
• Recurrent haemartheosis
COMPLICATION

66. MANAGEMENT OF RECURRENT PATELLAR
INSTABILITY
 Defined as the condition where patellar dislocation
had occurred at least twice,
or
where patellar instability following initial dislocation
had persisted for more than three months
 A large number of procedures have been described.
 No single surgery is universally successful
 approach is to identify the underlying problem that
cause the patello femoral instability and systemically
correct them

67. MANAGEMENT OF RECURRENT PATELLAR INSTABILITY
The surgical procedures are classified into proximal and distal
realingment
If the operation involves structures at or above the kneecap, it is
called a proximal and If the operation involves structures
below the kneecap, it is called a distal realignment.
Proximal Realignment Of Extensor Mechanism
1.Lateral retinacular release
2. Medial plication/ reefing
3. VMO advancement
4.MPFL reconstruction
Distal Realignment Of Extensor Mechanism
Medial or antero medial displacement of tibial tuberosity

68. MEDIAL PATELLO FEMORAL
LIGAMENT RECONSTRUCTION
-Medial patello femoral ligament (MPFL) is the
primary soft tissue passive restraint to pathologic
lateral patellar dislocation, and MPFL is torn when
patella dislocates, hence reconstruction of MPFL is
done in an attempt to restore its function.

69. MEDIAL PATELLO FEMORAL LIGAMENT
RECONSTRUCTION
indicated in : skeletally mature patient
excessive lateral laxity
normal trochlea
‘Q’ angle is normal
TT-TG distance is < 20mm
low grade trochlear dysplasia
Contraindications : skeletally immature

70. MEDIAL PATELLO FEMORAL LIGAMENT RECONSTRUCTION
Procedure
>Graft harvesting and graft preparation
 Patellar tunnel preparation
 Femoral tunnel preparation
 Femoral tunnel graft passage and fixation
 Graft passage through patellar tunnel and fixation
 Wound closure

71. Technique – Graft Harvesting
-autologus semitendinous hamstring(prefer) or
adductor magnus tendon graft used.
Make a 3cm incision 3cm medial to the inferior portion
of the tibial tuberosity.
And harvest the graft.

72. Technique – Graft Preparation
measure atleast 16cm of harvested
graft and remove any excess
length,place a whip stitch in each
tail of graft

73. Technique – Patellar Preperation
-Make a small incision just
superomedial asprct of patella
-Junction of Upper
1/3rd and lower 2/3rd
Should be at the
centre- not
violating ant.
Cortex or articular
surface.
Tunnel diameter-
Minimal to avoid
Patellar fracture

74. FEMORAL TUNNEL PREPARATION
-make a 3cm incision in between the adductor tubercle and the
medial epicondyle.
-select the site of femoral tunnel approximately 1cm distal and
5mm posterior to adductor tuberccle.

76. Graft Loop Through Patella

77. Graft was passed through a Soft Tissue Tunnel
between Medial Retinaculum and Joint
Capsule(extrasynovial)

78. GRAFT FIXATION
Graft Fixed to the Medial Epicondyle of
Femur

80. COMPLICATIONS OF MPFL
RECONSTRUCTIUON
• 1)RESIDUAL INSTABILITY
• 2)PATELLAR FRACTURE
• 3)DECREASED ROM OF KNEE JOINT
• 4)HAEMARTHROSIS AND WOUND
COMPLICATIONS
• 5)PATELLOFEMORAL ARTHROSIS
• 6)ANTERIOR KNEE PAIN
• Now a days due to modification in techniques
complications are very low and it considered as
low risk and high rewarding method.

81. Lateral release
>Indication-
1)tight lateral structure prevent patellar centering
2)lateral patellar pressure syndrome
3)Can be done in skeletally immature patients
>release to include-
1)Lateral retinaculum from distal third of vastus
lateralis
2)Lateral patellofemoral ligament
3)Lateral patellotibial ligament.

82. • Can be done open or arthroscopy procedure(now
a days arthroscopic release preferred)
• complication-
• 1)Extending the release too far can cause medial
subluxation of the patella; in fact.
** medial patella subluxation or dislocation is
almost always iatrogenic, secondary to an
overzealous lateral release.
• 2)injury to suerolateral geniculate vessel(to
prevent this make a superior anterolateral 2cm
insion starting just lateral to the proximal pole of
patella.
• Results varied,good results in short
term(metcalf,Simpson),poorer in long
term(Christensen)

83. Medial repair
• Anatomic and biomechanical studies have
indicated that the MPFL and the VMO are the
primary restraints to lateral patella translation,
particularly early in flexion before full trochlear
engagement.
• There are 3 types of primary procedures for
medial repair,The techniques include
• (1) plication of the medial patellar retinaculum,
(2) anatomic repair of the MPFL, and
• (3), anatomical repair surgery of the VMO.

84. Technique-
-make a 4cm incision at the superior pole of
patella,2cm medial and parallel to the medial
border of patella extending distally.
-identify the vastus medialis and medial
retinaculum,grasp these structure and pull them
laterally to assesthe integrity of adductor tubercle
attachment site.
-carefully incise the vastus medialis and medial
retinaculum along the medial border of patella
down to,but not through,the level of synovium.
-using no.2 ethibond suture,advance the medial
retinaculum to the medial border of patellausing
atleast four mattress suture.

85. Medial REEFING AND LATERAL
RELEASE(NAM AND KARZEL)
• Alters line of pull of quadriceps
• Does not alter Q angle or length of patellar
tendon
• Can be done in skeletally immature patient.
• 2 components –Lateral release + lateral and
distal advancement of medial structures in line of
VMO.

87. DISTAL REALIGNMENT SURGERY
aims to diminish the q angle or TT-TG distance with
anteromedialisation of tibial tuberosity and unloads
patello femoral articulation .
Indications
1. ↑ Q angle or ↑ TT-TG distance > 20mm
2. Patellar alta
3. Normal patellar glide
4. Medial facet arthritis
Contraindications
1. Skeletally immature patients
2. incompetent MPFL
3. Diffuse patellar arthritis

88. ELMSLIE-TRILLAT OPERATION
• The procedure consist of lateral retinacular
release,medial retinacular plication, and medial
transfer of tibial tuberosity.
• Tibial tuberosity is moved 8-10mm medially and
secured with a cancellous screw.
• Usually this method not indicated in atheletes
due to high mean load to failure and total energy
to failure rates.
• Specially reserved for patients with severe
patellofemoral degenerative changes.

89. TECHNIQUE
• Make a 6cm lateral parapatellar
incision approximatelly 1cm
lateral to the patellar tendon.
• Perform the lateral release,the
release is considered adequate
when the patellar articular
surface can be everted 90
degree laterally.
• Approach the tibial tubercle
through the same incision,using
a 2.5cm flat osteotome,raise a
flat 6cm long,7mm thick
osteoperiosteakl flap

90. • Rotate the flap medially,cracking
the cortex distally,and hold it in
place with a k-wire
• -knee is moved through a full
passive range of motion to
evaluate the patellar tracking.
• if tracking is acceptable,fix it
with one or two 4mm
cancellous screw

92. Fullkerson antero-medial tibial tuberosity
transfer
>Modification of Elimslie trillat method
 Routine lateral retinacular release is done
 An oblique osteotomy is made from anteromedially
close to anterior tibial crest directed in postero
lateral direction ,existing at lateral cortex posteriorly
 Bone pedicle is displaced in an antero medial
direction usually about 10to 15mm of anterization
depending on obliquity of osteotomy

93. • Advantage-
• Mechanical studies shows that elimslie-trillat
osteotomy(flat osteotomy)has significantly
higher mean load to failure and total energy
to failure then the fulkerson techniqur(oblique
osteotomy)

94. Hauser
Fulkerson

95. DEROTATONAL HIGH TIBIAL
OSTEOTOMY
• INDICATIONS-
1)Femoral anteversion(thigh foot angle>30
degree)
2)External tibial torsiuon
3)Tubercle sulcus angle angle more than 10
degree.

96. MANAGEMENT OF TROCHLEAR DYSPLASIA
Surgical indications
 High grade trochlear dysplasia with patellar instability in the absence of
patellofemoral osteoarthritis
 Type of dysplasia should be identified when deciding the procedure
 Associated abnormalities including TT-TG distance, patellar alta, patellar
tilt should be identified and rectified
 MPFL reconstruction is always done
Contra indications
 Skeletally immature patients
 Associated osteoarthritis

97. MANAGEMENT OF TROCHLEAR DYSPLASIA
Type A dysplasia : medial patellofemoral ligament reconstruction
Type B and D dysplasia : sulcus deepening trochleoplasty with MPFL
reconstruction
Type C dysplasia : lateral facet elevation trochleoplasty with MPFL
reconstruction

99. Thank you