Lonnie E. Paulos, MD
Medical Director
The Andrews-Paulos
Research & Education Institute
Gulf Breeze, FL
Knee Cap
The patella articulates with the femur….
Patella
It’s a joint
Sulcus
Femur
To function properly any joint must be...
Aligned (Straight)
Congruent (fits together)
Side view
Stable (norm ligaments)
Sunshine view
The patella-femoral joint rarely has
all three
The most common knee problem
seen by doctors
The majority of people have a
patella-femoral joint that is either...
Mal-aligned (not straight)
Incongruent (doesn’t fit)
Too loose (weak ligaments)
Too tight (contracted ligaments)
All of the above (miserable mal-alignment)
? Mean
Malalignment
Patella-femoral alignment is
• Determined by
skeletal alignment.
Develops from hip to
foot (genetics)
• Functional alignment
which requires normal
muscle balance and
conditioning during
activities
The “Maligned” Patella!
There is little or no
consensus as to what
constitutes malalignment
or what treatment should
be employed for
symptomatic patients...
The result is inconsistent treatment,
unpredictable outcomes and
occasionally increased symptoms
Anterior iliac spine
• Historically, Q angle
has been measured
with knee in extension
• Has never
demonstrated
Med. significance
Lat.
• ? Sulcus location
(Patella-Sulcus alignment)
Tibial
tubercl
e
Patella-Sulcus Alignment
Is determined by hip, thigh,
leg and foot alignment
which can be measured by
radiographs (CT scans)
and estimated by physician
examination.
Computerized Axial Tomography (CT
Scan)
Tubercle/Sulcus Position
• Full extension
• May identify abnormalities that
reduce with flexion
• Precise measures
• Distance between tibial tubercle
and trochlear sulcus
• >9 mm indicates lateralization of
tibial tubercle
Physical Examination
Skeletal Alignment
• Hip rotation
•Knee valgus or varus
• Knee ROM
• Patella-Sulcus angle
•Foot alignment
Axial Alignment
Knee valgus or varus
• Lateral insertion of patella tendon
• Normal  5° valgus
Saggital Alignment
• Hyper-extension
3° to 5° normal
• Flexion
140° to 150°
normal
Tubercle-Sulcus Angle
• Flexed knee Q angle
• Perpendicular to
transepicondylar axis
• Patella center to tubercle
• Knee flexed 90º
• Normal = 0º, abnl > 10º lat.
Kolowich, Paulos et. al 1990
AJSM 18:359-365
Rotational Alignment
Hip Rotation
• Ext. rotation  Int. rotation
• Hip assumes neutral
position for gait so toes
point forward
Hip Internal
• Diff > 60° no external
rotation => Abnormal
Hip External
Rotational Alignment
Thigh-foot angle
• Normal = 15° ext.
• > 30° - consider surgery
Foot Alignment
Pronation
• Assoc. ext. tibial rotation and
compensatory valgus
Incongruence
STRUCTURAL
&
ARTICULAR
Patellofemoral Imaging
• Radiographs – AP, lateral, axial
• Computed Tomography
• Magnetic Resonance
Imaging
• Helpful in evaluation, but
diagnosis of subluxation
or dislocation is clinical,
not radiographic
Patellofemoral Imaging
Axial Views
Laurin - 20º
Merchant - 45º
• Joint congruency
• Trochlear depth
• Lateral buttress
• Tilt
• Subluxation
Patellofemoral Joint Congruence
Alignment
Growth
Congruence
• Femoral sulcus shape  depth;
lateral condylar height
• Patella shape  facet size;
angle
• Patella height  alta; infera
“Geometric restraints”
Wyberg
Articular
•
•
•
•
•
Grade 0: healthy cartilage
Grade 1: cartilage soft spot or blisters
Grade 2: minor tears visible in the cartilage
Grade 3: deep crevices (>50% of cartilage layer)
Grade 4: exposed bone
“Chondromalacia”
Too Loose
Passive Laxity
Determined by
Ligament integrity
Geometry (Congruence)
Patellar Glide
Patellar Glide Test
0º Flexion
Determines
Medial/Lateral
Restraint
30º flexion
Congruence
3 to 4 quad glide  too loose
Passive Patellar Tilt
Determines lateral
and medial
Restraints
Female + 5º = +10º
Male 0°  + 5º
 Tilt  too loose
Lateral Patellar Compression
Syndrome (LPCS)
Too tight
• Lateral retinacular tightness – 0 or
negative tilt
• Lateral patella pain
• Radiographic patella tilt/overhang ±
• Arthroscopic lateral tracking with
lateral patellofemoral wear ±
NOT X-RAY Diagnosis!
Primary vs. Secondary
LPCS
Lateral Trackers
Hypermobile-Lateral Tracker
Time
LPCS
All of the above
Miserable Malalignment!
•
•
•
•
•
•
•
•
 Internal femoral torsion
 External tibial torsion
Dysplastic patella shape
Dysplastic femur sulcus
 T/S angle
Lateral tilt
 Medial glide
Flat feet
Treatment?
Accurate Evaluation
Joint reaction force
with congruence
Consensus Opinion
[patella-femoral
maladies]
=
muscle strength
+
balance
“envelope of function”
Scott Dye
function
“Envelope of Function
Excellent
Over-use
Strength
and
Balance
Functional
Capacity
Accident
Dis-use
Obesity
Bad
Mild
Major
Limb Malalignment
?
Treatment
Surgery  [Malalignment] + [Patholaxity] + [Incongruence]
Physical  [Muscle condition] + [Activity modification]
Therapy
Usually
1st Choice when treating P/F problems is
conservative (non-surgical) treatment
Surgery
Typical Non-Surgical
• Neuromuscular
facilitation
• Activity modification
• Weight loss
• Orthotics
• Bracing & Taping
But . . .
Dynamic (compensatory) Alignment
Maximum
Compensation
Minimum
Compensation
•Patient strides forward, one leg is lifted while
full weight is on the other leg. The swing leg is
subjected to rotational hip compensation,
mechanical alignment, and T/S angle
positioning of the tibia tubercle to the femoral
sulcus just prior to heel strike.
•Much like “lining up a putt” in golf, the
patella is aligned with the sulcus.
•At heel strike, the femur engages the patella
as the hip and femur finish rotating to the midpoint between internal and external hip
rotation in order to keep the foot pointed
forward during the foot-flat and toe-off phases
of gait.
•The femoral sulcus is pre-positioned in its
relationship to the tibial tubercle and actually
engages the more passive patella. If this fails
to occur, depending on the static and
geometric restraints present, the patella will
track lateral and spontaneously subluxate or
dislocate during gait just prior to the foot-flat
phase.
Dynamic Restraints?
• Quadriceps unit (mass action vector)
• PES anserine group (reduces T/S angle)
• Hip Abduction/Adduction (rotation)
Patellofemoral Joint
Functional Rehabilitation
•
•
•
•
•
•
•
•
Isometrics
Straight leg raises
Leg presses (standing)
Cycle
Patella
Forces
Swim
Low impact jumping
0°
Stretch cords
Progressive step-ups (8” max)
Standing
Sitting
Knee Flexion Angle
• Increase passive hip rotation & strength!
100°
Indications for Surgery
•
•
•
•
Failure of conservative care
Progressive P/F arthritis with pain
Recurrent subluxations / dislocations
Debilitating symptoms with daily activities
Amount and type of surgery depends
on the patient’s anatomy and severity
of problems
?
[malalignment] + [patholaxity] + [incongruence]
The surgeon should choose the
surgical procedure with the least risk
and highest chance of success
based on patient anatomy
Not the easiest!
High Risk
Proximal + Distal Realignment
Proximal Realignment
Lateral Release
Synovectomy/Chondroplasty
Low Risk
Procedure selected depends on age, goals, informed consent
Synovectomy/Chondroplasty?
• Pain + crepitation only
• Short term symptoms
• No instability
+
Lateral Release
☼
Primary Indication for
Isolated Lateral Release
• Failed conservative treatment
• A negative or neutral passive
patellar tilt (LPCS)
• NO or minimal instability or
malalignment
+
Proximal Realignment
(at the patella)
Indications
?
• Subluxating/dislocating
patella with medial laxity
• Minimal patella alta
• Minimal malalignment
• Failure of patella to center
after lateral release
• Failure to improve after
lateral release (6 to 9 mos.)
Proximal Realignment Procedures
Medial plication
• Mini-open
• Arthroscopic
Rarely Need
• VMO advancement
• MPFL reconstruction
or replacement
+
?
Distal Realignment Procedures
(at the tibia)
Indications
• Subluxating /
dislocating patella
•  T/S angle >15º
• Patella alta
• Patella infera
• Mal-alignment
Hauser Procedure
• Medial
• Posterior
Fulkerson Procedure
• Medial
• Anterior
Elmsley-Trillat Procedure
• Flat cut
• 5-6 cm tubercle shingle, intact
distally + med. sleeve
• Rotate tubercle medially 1-1.5cm
• Check tracking, tubercle sulcus
angle  0°
• Fix with 2 screws
A
B
C
Bench Mark Study
Lateral Patella Compression Syndrome (LPCS)
1990 Study
Failed vs. successful lateral release
Kolowich-Paulos
AJSM-1990
Mid-90’s
Proximal-Distal Results
256 patients
• 5 yr F/U
• > 80% satisfied
• < 5% recurrence rate
BUT…
• Gradual symptoms @ 24 mos. >30%
esp. for extreme T/S angles
?
Severe femoral-tibial torsion
Enlightened
• Stan James, M.D.
• Robert Tiege, M.D.
• Peter Stevens, M.D.
“Torsional Limb Mal-alignment”
Bruce, Stevens
J Pediatr Orthop, Jul-Aug 2004
Tiege, Robert
Meisler, James
Am J Ortho, Feb 1995
New Distal Procedure
De-Rotation high tibial osteotomy
D-HTO
Corrects significant external tibial torsion
and associated extreme T/S angle
A
B
C
0° T/S Angle
[T/F Angle] – [T/S Angle] <= + 15°
Never Negative
Miserable Malalignment
• Femoral malrotation
[Int – Ext]
2
≥ 30º
• Derotational osteotomy femur
• External tibial torsion ≥ 30º
• Derotational osteotomy tibia
• Supratubercular
• Mid-diaphyseal (immature)
• Lateral release
• ± medial ligament repair
2003
A crossover study was conducted of patients
with dislocating patellae and significant torsional
lower leg deformity who underwent a (D-HTO).
The results were compared to patients with
similar alignment and dislocating patellae who
underwent The Elmsley-Trillat Fulkerson (ETF)
proximal-distal realignment.
Questionnaires
1. Kujala scoring sheet
• Specific to patella-femoral joint
• Validated 1993 + 2003
• Reliability = 0.86, Consistency = 0.82
• Ceiling 19%, Floor 0%
2. The Knee and Osteoarthritis Score (KOOS)
• Patient based outcomes following TKA and osteoarthritis
3. The RAND 36-Item Health Survey (ver. 1.0)
• 8 Health concepts
“Gun-sight” CAT Scan
Confirmed Torsional Alignment
Instrumented Treadmill
•
•
•
•
•
51 - Retro-reflective markers
8 - Digital motion analysis - TM cameras
4 - 3D force transducers
Data low passed filtered (Butterworth dig. Filter)
Visual 3D real time software
Results
Stride Kinematics
Group I
Group II
Surgery
NonSurgery
Difference
(SD)
Surgery
NonSurgery
Difference
(SD)
p
value
Total Stride Time (s)
0.671
0.673
-0.002
(.005)
0.665
0.680
-0.014
(.005)
0.004
Single Stance Time (s)
0.380
0.382
-0.002
(.005)
0.374
0.388
-0.014
(.005)
0.004
Double Stance Times (s)
0.144
0.147
-0.002
(.004)
0.153
0.138
0.015
(.007)
0.004
Total Limb Contact Time (s)
0.289
0.293
-0.004
(.009)
0.277
0.306
-0.028
(.011)
0.004
Near Equal Significant
Non-Significant
Shown are means and mean differences (standard deviation) of surgery-side limb minus the non-surgery side limb. The p value is from
an independent samples Fisher-Pitman permutation test to allow for skewness in the difference score distributions.
The double stance time value indicates which limb was forward during each period of double stance within each stride.
Foot-External Rotation
Significant variability
Results
Kajula and Knee and Osteoarthritis Scale Scores
Preoperatively* and at Most Recent Follow-up Evaluation
Group I (Derotational high tibial osteotomy)
Kajula Score
KOOS Scores:
Pain
Symptoms
Activities of Daily Living
Sports and Recreation
Quality of Life
Group II (Proximal-distal)
Preoperative
Follow-up
p Value
Preoperative
Follow-up
p Value
50 + 23
80 + 10
< 0.001
55 + 22
65 + 16
NS
54 + 26
48 + 21
67 + 22
24 + 24
17 + 19
85 + 12
81 + 16
85 + 15
58 + 28
62 + 24
< 0.001
< 0.001
< 0.001
0.002
< 0.001
57 + 22
49 + 18
62 + 25
31 + 29
31 + 22
67 + 18
62 + 17
73 + 19
44 + 30
35 + 25
NS
0.02
0.03
NS
NS
p Value
Group I vs.
Group II
Follow-up
0.01
0.005
0.008
NS
NS
0.005
All values are mean + standard deviation. NS = not significant.
*There were no significant differences at the preoperative evaluation between Group 1 and Group 2.
**The between group comparisons were done using a multivariable linear regression comparing the group follow-up scores, controlling for both the
preoperative scores and time to follow-up evaluation, with p values adjusted for six multiple comparisons using Hochberg’s procedure.
Results
SF-36 Scores Preoperatively and at the
Most Recent Follow-up Evaluation
Group 1 (Derotational high tibial osteotomy)
Group 2 (Proximal-distal)
SF Factor
Preoperative
Follow-up
P Value
Preoperative
Follow-up
p value
P value
Group I vs.
Group II
Follow-up
Physical Functioning
Role Limitations Due to Physical Health
Role Limitations Due to Emotional
Problems
Energy/Fatigue
Emotional Well-Being
Social Functioning
Pain
General Health
47.1 ± 25.4
20.8 ± 41.0
75.0 ± 43.9
55.4 ± 21.9
56.0 ± 19.1
45.8 ± 22.9
51.5 ± 22.5
34.2 ± 27.6
87.9 ± 22.4
100 ± 0.0
94.4 ± 23.2
86.7 ± 15.1
88.0 ± 16.5
85.4 ± 14.6
95 ± 10.0
78.3 ± 22.4
< 0.001
< 0.001
NS
< 0.001
< 0.001
< 0.001
< 0.001
< 0.001
44.2 ± 30.3
65.4 ± 48.0
64.1 ± 48.6
60.8 ± 24.7
68.6 ± 20.3
59.6 ± 22.4
72.5 ± 16.4
51.4 ± 32.2
50.0 ± 27.1
78.8 ± 41.2
74.4 ± 44.2
65.8 ± 22.2
68.0 ± 20.9
65.0 ± 19.1
77.7 ± 13.1
53.4 ± 28.5
NS
NS
NS
NS
NS
NS
NS
NS
0.004
0.001
NS
0.007
< 0.001
< 0.001
< 0.001
0.001
All values are mean + standard deviation. NS = not significant.
*Between group comparisons were done using a multivariable linear regression comparing the follow-up scores, while controlling for the preoperative scores
and time to follow-up evaluation.
How much better is
D-HTO vs. Tubercle Transfer?
JAW DROPPING!
In closing:
Patella femoral surgery must be
undertaken only with a thorough
understanding of the problem, after
an accurate evaluation, exhaustive
conservative care and
with the utmost
caution.
¤