1

Evidence – Based Examination

and Treatment of the

Sports/Orthopedic Knee and

Patellofemoral Joint

@robptatcscs

Robert Manske, PT, DPT, SCS, ATC, CSCS

Wichita State University Department of

Physical Therapy

Via Christi Health

Wichita, KS

Anatomy and Biomechanics of

the Patellofemoral Joint

Robert C. Manske PT, DPT, MEd, SCS, ATC, CSCS

Professor

Wichita State Department of Physical Therapy

Via Christi Health

Wichita, KS

Knee Injuries

• 14-16% of all musculoskeletal injuries at

the high school level.

• 9000 knee surgeries performed on high

school athletes alone

National high school injury survey. Natl Athl Train Assoc News. April

1996:17-23.

Rice SG. Risks of injury during sports participation. In: Sullivan JA,

Anderson SJ, (eds). Care of the Young Athlete. Rosemont, IL: American

Academy of Orthopaedic Surgeons and the American Academy of

Pediatrics; 2000:9-18.

PFP• General practitioner sees an average of 5-6 new cases

per year, actual incidence in general population is

unknown.

• Higher incidence in females.

• Incidence rates of 25-43% in military and sports

medicine.

Callaghan M, Selfe J. Has the incidence of prevalence of patellofemoral pain in

the general population in the UK been properly evaluated. Phys Ther Sport.

2007;8:37-43.

Devereaux MD, Lachmann SM. Patello-femoral arthralgia in athletes attending

a Sports Injury Clinic. Br J Sports Med. 1984;18:18-21.

Thijs Y, Van Tiggelen D, Roosen P, De Clercq D, Witvrouw E. A prospective

study on gait-related intrinsic factors for patellofemoral pain. Clin J Sports

Med. 2007;17:437-445.

PFP• Investigate 2-year prognosis of knee pain among

adolescents with and without knee pain.

• 2200 aged 15-19 yrs old.

• 55% of those with knee pain continued to have

knee pain after 2 years

• 12% of those without knee pain at baseline had

pain after 2 years

• Those with pain more likely to decrease activity

Rathleff MS, Rathleff CR, Olesen JL, Rsmussen S, Roos WM. Is knee pain

during adolescence a self-limiting condition? Prognosis of patellofemoral pain

and other types of knee pain. Am J Sport Med. 2016;44(5):1165-1171.

Patellofemoral Anatomy

2

The Patella: The “little plate”

Primary role in promoting efficient

load transmission

Acts as bony shield to underlying

structures

Patella

• Embedded within

quadriceps

• Largest sesmoid in

body

• Inverted triangle with

apex directed inferior

Patella

• Anterior Surface

• Convex all directions

• Rough superior third

– Quadriceps tendon

• V-shaped point

– Patellar tendon

Patella

• Posterior Surface

• Central portion of patella has thickest cartilage ~ 5 mm

• < 1 mm in periphery of surfaces

• Up to 7 mm mid-patellar – Thickest in human body

Fulkerson JP. Disorders of the Patellofemoral Joint, 3rd ed. Williams

&Wilkins, Baltimore, MD, 1997.

Heegaard J, et al. The biomechanics of the human patella during passive knee

flexion. J Biomech. 1995;28:1265-1279.

Grelsamer RP, Weinstein CH. Applied biomechanics of the patella. Clin

Orthop Rel Res 2001;389:9-14.

Patella• Posterior Surface

• Bone mineral density greater in lateral portion of patella – Increased loads

• Inferior pole– Non articulating

• Vertical ridge

• Articular cartilage

• Divided equally

• Medial and lateral facets

Fulkerson JP. Disorders of the Patellofemoral Joint, 3rd ed. Williams

&Wilkins, Baltimore, MD, 1997.

Leppala J, et al. Bone mineral density in the chronic patellofemoral pain

syndrome. Calcif Tissue Int 1998;62:548-553.

Patella

• Posterior Surface

• Facets flat to biconvex

sup/inf and med/lat

• Second vertical ridge

• Odd facet

3

Distal Femur

• Distal Femur

– Femoral sulcus

– Patellar groove

– trochlea

• Ridge corresponds to that of posterior patella

• Lateral facet of sulcus higher than medial

Distal Femur

• Trochlear displasia

PFJ

• Attached from quads

to tibial tuberosity

• Patellar surface much

smaller than femoral

surface

• One of the most

incongruent joints in

body

Four – Quadrant Force Equality

PF Medial Side Restraints

• Dynamic

– VMO fibers

– Originates from adductor magnus and adductor longus tendon

– Inserts on superomedial half of patella

– Results in oblique pull

PF Medial Side Restraints

• Dynamic

– VMO fibers do not extend the knee

– VML fibers extend the knee

– VMO fibers provide medial dynamic stability to patella

– VMO dysplasia predisposes the patient to lateral subluxation

– Selective atrophy of VMO post Sx

4

PF Medial Side Restraints

• VMO

• “Key to the knee”

• Normal inserts 1/3 to ½ way down medial border of patella

• Pathologically may barely reach patella

• Only medial side dynamic restraint

Quadriceps

• Lieb and Perry

• VML 15-18° from

long axis of femur

• VMO 50-55° from

long axis of femur

Lieb FJ, Perry J: Quadriceps function: an anatomical and mechanical study

using amputated limbs. J Bone Joint Surg 1968;50A:1535-1548.

PF Medial Side Restraints

• Static

– Medial Retinaculum

– Medial capusle

– Medial PFL

Medial Patellofemoral Ligament

• Primary static restraint to lateral patellar

displacement at 20° of knee flexion,

contributing 60% of total restraining force.

• Medial retinaculum and patellotibial

ligaments minimal contributions at 11% and

5% respectively

Desio SM, Burks RT, Bachus KN. Soft tissue restraints to lateral

patellar translation in the human knee. Am J Sports Med 1998;26:59-65.

Medial Patellofemoral Ligament

• 55% of passive soft tissue restraint to lateral

patellar subluxation

Amis AA. Current concepts on anatomy and biomechanics of patellar

stability. Sports Med Arthrosc. 2007;15:48-56.

Medial Patellofemoral Ligament

• 20 limbs from 17

cadavers

• MPFL identified in

66.7%

• More commonly

found than LPFL

Waligora AC, Johanson NA, Hirsch BE. Clinical anatomy of the

quadriceps femoris and extensor apparatus of the knee. Clin Orthop Rel

Res 2009;467:3297-3306.

5

Dynamic Medial Restraints PF Lateral Side Restraints

• Dynamic

– Vastus lateralis

• Static

– Lateral retinaculum

• Superficial – IT

band to patella

• Deep

– ITB

– TFL

Dynamic Lateral Restraints

Patellofemoral Biomechanics

Patellar Function

• Facilitating extension of the knee by increasing the distance of the extensor apparatus

• Moment arm produces greatest quadriceps torque at 20-60°flexion

• Neutral position 0°

6

Patellar Function

• Guide for the quadriceps tendon

• Changes direction of quadriceps force –acting as a pulley

PF Joint Reaction Forces

(PFJRF)

• The measurement of compression of patella

against femur

• Greatest force occurs between 60-30°

– Values approaching 3000 Newtons

Huberti HH, et al. Force ratios in the quadriceps tendon and ligamentum

patella. J Orthop Res 1984;21:49-54.

PF Joint Reaction Forces

(PFJRF)

• PFJRF are equal and

opposite to R of

quadriceps tension and

patellar tendon tension

PFJRF• Increase as knee flexion increases

– Angle becomes more acute

– Lever arms of femur and tibia increase

PF Joint Reaction Forces

(PFJRF)

• OKC knee extension requires greater

amount of quad force

– Active insufficiency of quads

– Full effects of gravity

– Decreased biomechanical advantage

PFJRF

• Imbalance of quadriceps muscle that

produces a decrease in magnitude or

direction of tension of VMO may result in

significant displacement of patella laterally

placing the PFJRF almost entirely on the

lateral facet

Rand JA. The patellofemoral joint in total knee arthroplasty. J Bone

Joint Surg 1994; 76A:612-620.

7

Forces on the patella

• Walking 0.5-1.5x BW

• Stairs 3.0x BW

• Squatting 7-8x BW

Percy EC, Strother RT. Patellalgia. Phys SportsMed 1985;13:43-59.

Huberti HH, Hayes WC. Patellofemoral contact pressures. The incidence of

Q-angle and tendofemoral contact. J Bone Joint Surg 1984;66A:715-724.

Reilly DT, Martens M. Experimental analysis of the quadriceps muscle force

and patello-femoral joint reaction force for various activities. Acta Orthop

Scand 1972;43:126-137.

Contact Stress

One part or another of patellar cartilage is

loaded throughout the entire flexion-

extension cycle

Except the earliest degrees of knee flexion

Grelsamer RP, Weinstein CH. Applied biomechanics of the patella.

Clin Orthop Rel Res 2001;389:9-14.

CKC Exercises

Contact Pressures and PFJ

• CKC Exercises

• As knee extends PFJ

contact stress decreases

despite”

– decreased contact area

– May be due to decreased

torque of gravity

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OCK Exercises

Contact Pressures and PFJ

• OKC Exercises

• As knee extends PFJ

contact stress increases

due to:

– Increased PFJR force and

decreased contact area

Contact Pressures and PFJ

• High contact pressure

activities

• Loaded OKC knee

extension exercise

• CKC knee extension

activities in > 50° of

knee flexion

Contact Pressures and PFJ

• Low contact pressure

activities

• Loaded OKC knee

extension exercise from

90°-50° & 20°-0°

• CKC knee extension

activities in < 50° of

knee flexion

PF Contact Surface Area

9

PF Contact Surface AreaDegree of

Flexion

Patella Articulation Femoral

Articulation

0° Femoral Sulcus Min. bony

contact

20°-30° Inf. facets Mid. fem.sulcus

60° mid. facets Superior femoral

notch

90° mid/sup lat facets Sup fem notch

120° Lat mid and sup

facet

Sup fem notch/

LFC

135° Lat mid facet/lat

sup facet/ odd

LFC/lat surface

of MFC

Contact Stress

Distal portion of patella loaded as knee flexes

and contact area migrates proximally with

progressive flexion

At 90° the contact area is located proximally,

after which contact area moves back toward

central aspect of patella

Grelsamer RP, Weinstein CH. Applied biomechanics of the patella.

Clin Orthop Rel Res 2001;389:9-14.

Articular Surface Of The Patella

Quadriceps Angle

“THE LAW of VALGUS”

Fulkerson JP and Hungerford DS:

Disorders of the Patellofemoral Joint.

2nd ed. Baltimore, MD: Williams and

Wilkins

PF Signs

• Increased Q-angle

– More significant

for females

• Normal

Males: 8°-14°

• Females: 15°-

17°

10

Q-Angle • Originally described

by Brattstrom

• “the angle formed by

the resultant vector of

the quadriceps force

and the patellar tendon

with the knee in an

“extended, end-

rotated” position.”

Brattstrom H. Shapre of the intercondylar groove normally and in recurrent

dislocation of the patella. Acta Orthop Scand Suppl 1964;68:1-48.

Q-Angle • Angle formed by the

intersection of a line drawn from the anterior superior iliac spine to the midpoint of the patella

• Proximal extension of the line from the tibial tubercle to the midpoint of the patella

Neuman DA. Kinesiology of the Musculoskeletal System: Foundations

for Physical Rehabilitation. Philadelphia, PA: Mosby, Inc., 2002.

Q-Angle

• Theory centers around

this measurement

• Offset in force vectors

from the quadriceps

force and force from

patellar tendon

Q-Angle

• A larger Q-angle may

create a larger lateral

vector and potentially a

greater predisposition to

lateral patellar tracking

when compared to a

smaller Q-angle

Schulthies SS et al: Does the Q angle reflect the force on the patella in the

frontal plane? Phys Ther 1995;75:24-30.

Measuring Q angle

• Standing

Caylor D, Fites R, Worrell TW: The relationship between

quadriceps angle and anterior knee pain syndrome. J Orthop

Sports Phys Ther 17(1):11-16, 1993.

Cowan DN, et al: Lower limb morphology and risk of

overuse injury among male infantry trainees. Med Sci Sports

Exerc 28(8):945-952, 1996

Roy S, Irvin R: Sports Medicine: Prevention, Evaluation,

Management, and Rehabilitation, Englewood Cliffs:

Prentice-Hall, Inc., 1983.

Measuring Q angle

• Dynamically

Caylor D, Fites R, Worrell TW: The relationship between

quadriceps angle and anterior knee pain syndrome. J Orthop

Sports Phys Ther 17(1):11-16, 1993.

Kernozek TW, Greer NL: Quadriceps angle and rear-foot

motion: Relationships in walking. Arch Phys Med Rehabil

74(4):407-410, 1993

11

Measuring Q angle

• With Quadriceps Contracted

Fairbank JCT, et al: Mechanical factors in the incidence of

knee pain in adolescents and young adults. J Bone Joint Surg

66B(5):685-693, 1984.

Guerra JP, Arnold MJ, Gajdokik RL: Q-angle: Effects of

isometric quadriceps contraction and body position. J Orthop

Sports Phys Ther 19(4):200-204, 1994.

Measuring Q angle

• With Standardized Foot Positions

Cowan DN, et al: Lower limb morphology and risk of

overuse injury among male infantry trainees. Med Sci Sports

Exerc 28(8):945-952, 1996.

Guerra JP, Arnold MJ, Gajdokik RL: Q-angle: Effects of

isometric quadriceps contraction and body position. J Orthop

Sports Phys Ther 19(4):200-204, 1994.

Reider B, Marshall JL, Warren RF: Clinical characteristics of

patellar disorders in young athletes. Am J Sports Med

9(4):270-274, 1981.

Lack of

standardization of a

measurement

technique still a

problem!

Q-Angle

• Relationship between Q-

angle and clinical signs

and symptoms has not

always been consistent

Livingston LA: The Quadriceps angle: a review of the literature. J

Orthop Sports Phys Ther 1998;28:105-109.

Q-Angle

• May be problematic in subpopulation of

those with PFP

• Etiologic factors unrelated to Q-angle may

be more dominant in certain individuals

• Remember: Q-Angle is “static”

measurement that measures dynamic

function!

Femoral Anteversion and

Retroversion Effects on Q-Angle

12

Q-Angle

• Can vary significantly when measurement

taken standing due to foot position.

• Supine measurement taken as static position

• Standing can be taken as a more

“functional” measurement.

Q-Angle

• Although and increased Q-angle is

traditionally associated with a valgus knee,

some of the highest Q angles are found in

patients with a combination of genu varus

and proximal tibial torsion.

Hughston JC, Walsh WM, Puddu G. Patellar subluxation and

dislocation. In: Saunders Monographs in Clinical Orthopeadics,

Philadelphia. Saunders, 1984.

Olerud C, Berg P. The variation of the quadriceps angle with

different positions of the foot. Clin Orthop 1984;191:162-165.

Patellar OrientationClinical Assessment of PF

Alignment

Patellar Position

• Assess medio-lateral

glide and patellar tilt

with MRI

• 24 subjects; 16 males;

8 females

• * Examiner -15 years

of experience

McEwan I, et al. The validity of clinical measures of patella position.

Man Ther 2007;12:226-230.

Patellar Position

• Good correlation

between findings of

clinical test of

medio-lateral

position and MRI

(r=0.611, p=0.002)

McEwan I, et al. The validity of clinical measures of patella position.

Man Ther 2007;12:226-230.

13

Patellar Position

• If found lateral

patellar tilt, patellar

tilt angle via MRI

was > 5°

McEwan I, et al. The validity of clinical measures of patella position.

Man Ther 2007;12:226-230.

• 30 patients with tilt

• 51 patients without tilt

• Found patients with significant tilt on PE can be

expected to have >10° tilt on MR

Grelsamer RP, Weinstein CH, Gould J, Dubey A. Patellar tilt: The

physical examination correlates with MR imaging. Knee. 2008;15:3-8.

Grelsamer RP, Weinstein CH, Gould J, Dubey A. Patellar tilt: The

physical examination correlates with MR imaging. Knee. 2008;15:3-8.

• Any MR angle <10° is associated with the absence

of significant tilt on MR

• *This study should not imply abnormal tilt in any

given patient automatically implies pathology

• Patients with any tilt on PE can be expected to

have an MRI tilt angle that is 10° or >.

Grelsamer RP, Weinstein CH, Gould J, Dubey A. Patellar tilt: The

physical examination correlates with MR imaging. Knee. 2008;15:3-8.

Assessment of Patellar Position?

14

Clinical examination and

measurement of patellofemoral

alignment with visual

examination, using calipers or

goniometer’s may be unreliable

when performed within or

between testers

Intratester Kappa’s displayed

questionable reliability for:

• Mediolateral tilt 0.57

• Superior/inferior tilt 0.50

• Rotation 0.41

• Mediolateral position 0.40

Tomsich DA, Nitz AJ, Threlkeld AJ, Shapiro R. Patellofemoral

Alignment: Reliability. J Orthop Sports Phys Ther 1996;23(3):200-208

Intertester Kappa’s displayed

questionable reliability for:

• Mediolateral tilt 0.18

• Superior/inferior tilt 0.03

• Rotation 0.30

• Mediolateral position 0.03

Tomsich DA, Nitz AJ, Threlkeld AJ, Shapiro R. Patellofemoral

Alignment: Reliability. J Orthop Sports Phys Ther 1996;23(3):200-

208

The low intratester and intertester

agreement coefficients were

clinically unacceptable and

suggest that treatment decisions

based on these measurements

should not be made!

What passes for PF malalignment

at one clinic or with one therapist

may not be the deemed the same

problem at another clinic because

clinicians cannot agree on basic

physical examination data.

Reliability of Tests for PF

Alignment (Intertester)

• Medial/lateral displacement 0.10

• Medial/lateral tilt 0.21

• Anterior/posterior tilt 0.24

• Medial/lateral rotation 0.36

Fitzgerald GK, McClure PW. Reliability of measurements obtained with

four tests of patellofemoral alignment. Phys Ther 1995;75(2):84-92.

15

Smith TO, et al. An evaluation of the clinical tests and outcome

measures used to assess patellar instability. The Knee. 2008;15:255-262

Smith TO, et al. The reliability and validity of assessing medio-lateral

patellar position: a systematic review. Man Ther. 2008;:1-8.

Medial/lateral Position

AUTHOR Inter-Tester Intra-Tester

Fitzgerald and McClure, 1995 0.10 NA

Herrington, 2008 NA 0.86

Herrington, 2002 M-.91; L-.94 NA

Herrington, 2006 NA 0.99

Herrington and Nester, 2004 NA 0.99

McEwan et al, 2007 NA 0.86

Powers et al, 1999 NA 0.91

Tomsich et al, 1996 0.14 0.70

Watson et al, 1999 0.02 0.11-0.35

Fitzgerald GK, McClure PW. Reliability of measurements obtained with four tests

for patellofemoral alignment. Phys Ther. 1995;75:84-92.

Herrington LC. The inter-tester reliability of a clinical measurement used to

determine the medial/lateral orientation of the patella. Man Ther. 2002;7:163-167.

Herrington LC et al. the relationship between patella position and length of

iliotibial band as assessed using Ober’s test. Man Ther. 2006;11:182-186.

Herrington LC. The difference in a clinical measure of patella lateral position

between individuals with patellofemoral pain and matched controls. J Orthop

Sports Phys Ther. 2008;38:59-62.

Herrington LC, Nester C. Q-angle undervalued? The relationship between Q-angle

and medio-lateral position of the patella. Clin Biomech. 2004;19:1070-1072.

McEwan I, Herrington L, Thom J. The validity of clinical measures of patella

position. Man Ther. 2007;12:226-230.

Powers C et al. Criterion-related validity of a clinical measurement to determine

the medial/lateral component of patellar orientation. J Orthop Sports Phys Ther.

1999;29:372-377.

Tomsich DA, Nitz AJ, Threlkeld AJ, Shapiro R. Patellofemoral Alignment:

Reliability. J Orthop Sports Phys Ther 1996;23(3):200-208.

Watson CJ et al. Reliability of McConnell’s classification of patellar orientation in

symptomatic and asymptomatic subjects. J Orthopedic Sports Phys Ther.

1999;29:378-385.

Thank You!Robert C. Manske, PT, DPT, MEd, SCS,

ATC, LAT, SCS, CSCS

Professor

Wichita State University Dept. Physical Therapy

1845 North Fairmount

Wichita, Kansas 67260-0043

316-978-3702

robert.manske@wichita.edu