Lonnie E. Paulos, MD

Medical Director

The Andrews-Paulos

Research & Education Institute

Gulf Breeze, FL

Knee Cap

The patella articulates with the femur….

It’s a jointPatella

Sulcus

Femur

To function properly any joint must be...

Aligned (Straight)

Congruent (fits together)

Stable (norm ligaments)

Side view

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

• Determined by skeletal alignment. Develops from hip to foot (genetics)

• Functional alignment which requires normal muscle balance and conditioning during activities

Patella-femoral alignment is

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

The “Maligned” Patella!

Anterior iliac spine

Med.Lat.

• Historically, Q angle has been measured with knee in extension

• Has never demonstrated significance

• ? Sulcus location (Patella-Sulcus alignment)

Tibial

tubercle

Is determined by hip, thigh, leg and foot alignment which can be measured by radiographs (CT scans) and estimated by physician examination.

Patella-Sulcus Alignment

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 ExaminationSkeletal 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

•Diff > 60° no external rotation => Abnormal

Hip Internal

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 ImagingAxial Views

Laurin - 20º

Merchant - 45º• Joint congruency

• Trochlear depth• Lateral buttress

• Tilt• Subluxation

Patellofemoral Joint Congruence

• Femoral sulcus shape depth; lateral condylar height

• Patella shape facet size; angle

• Patella height alta; infera

Alignment Growth Congruence

“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

0º Flexion

Determines

Medial/Lateral

Restraint

30º flexion

Congruence

Patellar Glide Test

3 to 4 quad glide too loose

Passive Patellar Tilt

Determines lateral and medial Restraints

Female + 5º = +10ºMale 0° + 5º

Tilt too loose

?Too tight

• Lateral retinacular tightness – 0 or negative tilt

• Lateral patella pain• Radiographic patella tilt/overhang ±• Arthroscopic lateral tracking with

lateral patellofemoral wear ±

Lateral Patellar Compression Syndrome (LPCS)

NOT X-RAY Diagnosis!

Primary vs. Secondary

Lateral Trackers LPCS Time

LPCS Hypermobile-Lateral Tracker

?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

Accurate Evaluation

Treatment?

Joint reaction force with congruence

Consensus Opinion

[patella-femoral maladies]

muscle strength + balance

“envelope of function” Scott Dye

function=

Time

“Envelope of FunctionCompensated

Compensated

Mild MajorLimb Malalignment

Excellent

Bad

Strength and

Balance

FunctionalCapacity

Over-use

Obesity

Accident

Dis-use

?Surgery [Malalignment] + [Patholaxity] + [Incongruence]

Physical [Muscle condition] + [Activity modification]Therapy

Treatment

1st Choice when treating P/F problems is conservative (non-surgical) treatment

Surgery

Usually

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 mid-point 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.

• Quadriceps unit (mass action vector)

• PES anserine group (reduces T/S angle)

• Hip Abduction/Adduction (rotation)

Dynamic Restraints?

Patellofemoral Joint

Functional Rehabilitation• Isometrics• Straight leg raises• Leg presses (standing)• Cycle• Swim• Low impact jumping• Stretch cords

• Progressive step-ups (8” max)

• Increase passive hip rotation & strength!

Patella Forces

Knee Flexion Angle

Standing

Sitting

100°0°

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!

Proximal + Distal Realignment

Proximal Realignment

Lateral Release

Synovectomy/Chondroplasty

High Risk

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

Indications• Subluxating /

dislocating patella T/S angle >15º• Patella alta• Patella infera• Mal-alignment

(at the tibia)

+

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

1990 StudyFailed vs. successful lateral release

Kolowich-Paulos

AJSM-1990

Bench Mark Study

Lateral Patella Compression Syndrome (LPCS)

Proximal-Distal Results256 patients

• 5 yr F/U• > 80% satisfied• < 5% recurrence rate

BUT…• Gradual symptoms @ 24 mos. >30%

esp. for extreme T/S angles

Mid-90’s

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

[T/F Angle] – [T/S Angle] = + 15°<

0° T/S Angle

Never Negative

Miserable Malalignment

• Femoral malrotation ≥ 30º• Derotational osteotomy femur

• External tibial torsion ≥ 30º• Derotational osteotomy tibia

• Supratubercular• Mid-diaphyseal (immature)

• Lateral release• ± medial ligament repair

[Int – Ext]

2

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.

Questionnaires1. 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 KinematicsGroup I Group II

Surgery Non-Surgery

Difference (SD)

Surgery Non-Surgery

Difference (SD)

pvalue

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

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.

Near Equal Significant Non-Significant

Foot-External Rotation

Significant variability

Group II (Proximal-distal)Group I (Derotational high tibial osteotomy)

Results

Kajula and Knee and Osteoarthritis Scale Scores Preoperatively* and at Most Recent Follow-up

Evaluation

Preoperative Follow-up p Value Preoperative Follow-up p Value

p ValueGroup I vs.

Group IIFollow-up

Kajula ScoreKOOS Scores: Pain Symptoms Activities of Daily Living Sports and Recreation Quality of Life

50 + 23

54 + 2648 + 2167 + 2224 + 2417 + 19

80 + 10

85 + 1281 + 1685 + 1558 + 2862 + 24

< 0.001

< 0.001< 0.001< 0.0010.002

< 0.001

55 + 22

57 + 2249 + 1862 + 2531 + 2931 + 22

65 + 16

67 + 1862 + 1773 + 1944 + 3035 + 25

NS

NS0.020.03NSNS

0.010.0050.008NSNS

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 valueGroup I vs.

Group IIFollow-up

Physical FunctioningRole Limitations Due to Physical HealthRole Limitations Due to Emotional ProblemsEnergy/FatigueEmotional Well-BeingSocial FunctioningPainGeneral Health

47.1 ± 25.420.8 ± 41.075.0 ± 43.955.4 ± 21.956.0 ± 19.145.8 ± 22.951.5 ± 22.534.2 ± 27.6

87.9 ± 22.4100 ± 0.0

94.4 ± 23.286.7 ± 15.188.0 ± 16.585.4 ± 14.695 ± 10.0

78.3 ± 22.4

< 0.001< 0.001

NS< 0.001< 0.001< 0.001< 0.001< 0.001

44.2 ± 30.365.4 ± 48.064.1 ± 48.660.8 ± 24.768.6 ± 20.359.6 ± 22.472.5 ± 16.451.4 ± 32.2

50.0 ± 27.178.8 ± 41.274.4 ± 44.265.8 ± 22.268.0 ± 20.965.0 ± 19.177.7 ± 13.153.4 ± 28.5

NSNSNSNSNSNSNSNS

0.0040.001NS

0.007< 0.001< 0.001< 0.0010.001

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.

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