Post on 16-Jul-2015
Professor Deiary F KaderDepartment of Sport, Exercise, Northumbria University, Newcastle
www.oasir.co.uk
Knee Surgeon, Nuffield Hospital, Newcastle upon Tyne
PATELLOFEMORAL JOINT INSTABILITY
PostGrad Orth Deiary Kader
Postgraduate OrthopaedicsFRCS(Tr&Orth) Revision Course
Newcastle Upon Tyne 16-21 March 2015
•
Professor Deiary KaderConsultant Orthopaedic & Trauma Surgeon
Knee Surgeon
Nuffield Hospital Newcastle
NGMV Charity
PLAN
Presentation
Frank dislocation
Subluxation
Symptomatic instability
Pain due to mal-tracking
PATELLAR DISLOCATION
Re-dislocation rate
First Time 17-20%
Second Time 44%-71%
High dissatisfaction following
conservative Rx
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
TrigonometryFjf=Ff cos(angle/2)
PostGrad Orth Deiary Kader
PATELLAR STABILITY
DETERMINED BY
– Soft Tissue 0-300
Muscles
Ligaments MPFL (at 200-300)
– Bone morphology >300
CAUSES OF PATELLA INSTABILITY
• Soft Tissue• Global --HMS (Hyperlaxity)• 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)
WHY THE PATELLA IS UNSTABLE
Lower limb Malalignment??
– Femur, tibia or foot pronation
Osseous abnormalities??– Patella alta– Increased Q angle – Trochlea dysplasia
Soft Tissue??– HMS– MPFL Insufficiency– Muscle or ITB
Gait ??
PostGrad Orth Deiary Kader
KNEE ASSESSMENT
Leg Alignment Varus/valgus
Soft tissue imbalance
Ligament assessment (ACL,PCL, MCL, LCL)
Meniscal assessment
Medial/ Lateral compartment OA
Hip , Spine, peripheral pulses
Apprehension test
PATELLA ASSESSMENT
Beighton Score0---9
Patella Alignment (Q Angle)
Dislocation in extn (J Sign)
Quads Bulk/ ITB (Ober's test)
Hamstring Tightness
Patella height Alta/Baja
Patella Mobility (N@300=<1/2)
Parapatellar tenderness
Patella Apprehension
PFJ Crepitus
PFJ Compression (Clarke test)
Trochlea Depth Normal (1380) – Shallow ,Flat , Convex , Cliff
Many potential problems
• Crude measure
• How it is measured?– Flexion, Extension
– Standing, Sitting, Supine
– Muscle relaxed/tense
• No standard method
Q- Angle
IMAGING OF THE PATELLOFEMORAL JOINT
AP and Lateral Knee x-ray
Merchant’s view
MRI Axial view
CT Rotational Profile
Merchant’s
Trochlea dysplasia
Blumensaat's line
Normal Trochlea Depth
NORMAL
MEASURING PATELLA HEIGHT
Caton – Deschamps index =1.2
Blackburne-peel index = 1.12
PostGrad Orth Deiary Kader
MPFL injury
Patella pain
Articular Damage
MRI SCAN
ROTATIONAL PROFILE CTEVIDENCE BASED INTERVENTION
1. Femoral Anteversion N=50 -150
2. Knee rotation N=30
3. External Tibial torsion 250-300
4. TT:TG offset (N= 10-19mm)
5. Patella index
6. Patella Tilt (N=average QD&QC <200)
7. Trochlea Tilt (N>130)
8. Trochlea DepthNormal (1380+/- 60)
TRUE Q ANGLE, MEASUREMENT OF THE TIBIAL TUBEROSITY-TROCHLEAR GROOVE (TT/TG)
DISTANCE
Normally TT/TG = 2-9 mm pathologic measure is > 19 mm
PostGrad Orth Deiary Kader
HOW USEFUL IS TT:TG
• Large variation in normal value (patient size and height)
• Poor interrater reliability 3-5mm measurement error– Trochlea ?deepest point of
– Tib Tub bony landmark vs Central point of PT attachment 4mm
• What condition? – Flexion or extension
– Weight bearing 5mm
• MRI or CT measurement
TREATMENT OF PATELLA INSTABILITY
Conservative firstQuads strengthening Core stabilityMcConnell TapingInsolesGait
Med Epicondyle
Add Tubercle
Patella
MPFL
PostGrad Orth Deiary Kader
PostGrad Orth Deiary Kader
BONY TUNNEL
PostGrad Orth Deiary Kader
MX OF PATELLA INSTABILITY
Patellofemoral Instability with Malalignment
Distal Realignment
tibial tubercle transfer
Combined
MPFL Recon
FULKERSON'S TECHNIQUE OF ANTEROMEDIALIZATION
A steeper osteotomy plane will produce more anteriorization along with medialization
OTHER PATELLOFEMORAL PROBLEMS
Patella Alta
– Distal transfer (Distalization)
Trochlea Dysplasia
– Trochloplasty
PostGrad Orth Deiary Kader
1.4 cm
Patella alta
TROCHELOPLASTY
TAKE HOME MESSAGE
The approach to patellar instability should be
individualised and tailored to each patient’s
symptoms, anatomy and physical demands
PostGrad Orth Deiary Kader
24 years old female doctor had a permanents dislocation of the patellaTreated with1. Lateral release2. Tib Tub Medialisation3. Tib Tub Distalisation4. Trochleaoplasty5. MPFL Reconstruction
PostGrad Orth Deiary Kader
TREATMENT SUMMARY
MPFL Reconstruction (very popular >80%)
Tib Tub Medialisation on the decline
Tib Tub Distalisation excellent procedure
Trochleoplasty
Distal femoral Osteotomy
THANK YOU