The Patellofemoral Articulation

1
Chapter 7

• The Patellofemoral Articulation

2
Introduction

• Separated from the knee chapter because of
  differences in the mechanisms and onset of injury
• Injury is usually due to overuse, congenital
  malalignment, or structural insufficiency

3
Clinical Anatomy

• Patella is largest sesamoid bone in body
• Anatomical design allows for
• Increased efficiency of quadriceps muscle group
• Protection of anterior portion of knee joint
• Absorption and transmission of patellofemoral
  joint reaction forces (forces transmitted through
  articular surfaces)
• Shape of patella
• Figure 7-1, page 244

4
Clinical Anatomy

• Articular surface of patella
• Figure 7-2, page 244
• Patella tracks medially during range of 45o to
  18o as knee moves from flexion to extension
• During final 18o of extension, patella tracks
  laterally
• During flexion and extension patella tracks
  within femoral trochlear groove (between the 2
  femoral condyles lined with articular cartilage)

5
Clinical Anatomy

• Articulation of patellofemoral joint
• Table 7-1, page 245
• Compressive forces
• Walking .5 times body weight
• Walking up/down stairs or running hills 3.3
  times body weight
• Lateral retinaculum
• From vastus lateralis and IT band to lateral
  border

6
Clinical Anatomy

• Medial retinaculum
• Vastus medialis and adductor magnus to medial
  border
• Medial and lateral patellofemoral ligaments
• Superior portion on fibrous capsule thickens and
  inserts on patellas superior border

7
Muscular Anatomy and Related Soft Tissue

• Quadriceps muscles
• Flexion patella is pulled inferiorly by patella
  tendons attachment to tibial tuberosity
• Extension quadriceps femoris and its tendon
  pull patella superiorly
• Length of patella is approximately same length as
  the long axis of the patella
• Figure 7-4, page 245

8
Muscular Anatomy and Related Soft Tissue

• Vastus lateralis pulls patella laterally
• Vastus medialis (VMO) guides patella medially
  and prevents lateral patellar subluxation
• Tight IT band can accentuate the lateral tracking
  of patella, resulting in subluxations or patellar
  malalignment

9
Muscular Anatomy and Related Soft Tissue

• Alignment of foot and normal flexibility of
  triceps surae and hamstring muscles are needed
  for adequate knee ROM and normal patellofemoral
  mechanics
• Example increased foot pronation increased
  internal tibial rotation rotation of tibial
  tuberosity toward midline

10
Bursa of the Extensor Mechanism

• Varying numbers of bursa being directly involved
  with extensor mechanism
• 4 found consistently in population
• Suprapatellar bursa
• Prepatellar bursa
• Subcutaneous infrapatellar bursa
• Deep infrapatellar bursa
• Figure 7-5, page 246

11
Clinical Evaluation of the Patellofemoral
Articulation

• Dysfunction of joints superior to or inferior to
  knee may manifest themselves as patellofemoral
  pain
• Patient preparedness
• Clinician preparedness

12
History

• Mechanism and onset of injury
• Acute vs. chronic or insidious onset
• Chondromalacia Patella
• Softening and wearing away of patellas hyaline
  cartilage grinding
• Box 7-1, page 247
• Clarkes sign - Box 7-5, page 253
• When pain occurs
• Location of pain

13
History

• Level of activity
• Prior surgery
• Relevant past history

14
Inspection

• Patella alignment
• Patellar alignment
• Figure 7-6, page 247
• Patellar malalignment
• Box 7-2, page 248
• Figure 7-7, page 247
• Posture of knee
• Genu varum, valgum, recurvatum

15
Inspection

• Q angle
• Relationship between line of pull of quadriceps
  and the patellar tendon
• Box 7-3, page 250
• Box 7-4, page 251
• Tubercle sulcus angle
• Relationship between tibial tuberosity and
  inferior patellar pole
• Leg length difference
• Foot posture
• Areas of scars

16
Palpation

• Refer to clinical proficiencies
• Utilize pages 249 253

17
Range of Motion Testing

• AROM
• Flexion to extension patella glides superiorly
  and somewhat laterally
• Tightness of lateral structures may accentuate
  lateral displacement
• Flexion patella glides inferiorly and medially
• RROM
• Pain during movement may indicate malalignment
• Open and closed kinetic chain

18
Range of Motion Testing

• Lower extremity flexibility
• Quadriceps, hamstrings, IT band, triceps surae
• Tightness may
• Result in decreased functional ROM
• Force the quadriceps to exert more pressure on
  patella
• Cause patellar tracking deficits

19
Ligamentous Testing

• Evaluate knee ligaments
• Laxity in knee joint can result in abnormal
  patellar tracking, secondary to uniplanar or
  rotatory shifting of tibia or femur, causing
  patellofemoral pain
• Ligamentous and capsular stability of patella is
  based on presence of patellar tilt and amount of
  glide available to patella

20
Ligamentous Testing

• Patellar Glide
• Figure 7-9, page 254
• Box 7-6, page 255
• Patellar Tilt
• Box 7-7, page 256
• Synthesis of Findings
• Relationship between patellar glide and tilt

21
Neurologic Testing

• Same as described in Chapter 6

22
Pathologies and Related Special Tests

• patellofemoral dysfunction and patellofemoral
  pain syndrome used to describe wide range of
  symptoms
• Onset may occur during inactivity (theater knee)
  and/or during or after activity
• Differentiation between meniscal and patellar
  pain
• Table 7-2, page 257
• Evaluation Map page 257

23
Patellofemoral Pain Syndrome

• All-inclusive diagnosis for pain in and around
  the joint that cannot be explained by a specific
  pathology
• Signs and symptoms
• Insidious onset occasionally caused by trauma
• Primary complaint of anterior knee pain caused by
  activity, pain may be constant
• Stair climbing, sitting for long periods
• swelling

24
Patellofemoral Pain Syndrome

• Signs and symptoms continued
• Pain increased with AROM and RROM
• Surrounding tissues evaluate for tightness and
  hyperlaxity by assessing patellar glide and tilt
• Assess subtalar joint
• Treatment
• Modify activity, NSAIDs, ice, patellar
  mobilization and passive stretching, flexibility
  and strength training
• Orthotics, patellar taping

25
Patellar Maltracking

• Normal tracking depends on relationships between
• Alignment of femur on tibia
• Q angle
• Integrity of soft tissue restraints
• Foot mechanics
• Flexibility of triceps surae, quads, hamstrings,
  IT band
• Table 7-3, page 258

26
Patellar Maltracking

• Predisposing factors
• Congenital dysfunction
• Injury to patella or knee
• Increased body weight
• Gait mechanics
• Gradual onset of symptoms
• Redistribution of forces along patellar facets
• Pain during ADLs

27
Patellar Subluxation and Dislocation

• Acute, chronic, or congenital laxity of medial
  patellar restraints or abnormal tightness of
  lateral retinaculum results in increased lateral
  glide of patella
• Predisposes patient to subluxation or dislocation
• Subluxations can occur without patient knowing it
• Dislocations shift patella laterally and lock out
  of place, obvious deformity and quadriceps spasm
• Figure 7-10, page 259

28
Patellar Subluxation and Dislocation

• Most apt to dislocate or subluxate within 20 to
  30 degrees of knee flexion or after valgus blow
  to knee
• May result in fractured patella, osteochondral
  damage, bone bruises, osteochondritis dissecans
• Multiple incidences result in wearing of
  articular cartilage

29
Patellar Subluxation and Dislocation

• Predisposing factors
• Hypomobile medial glide
• Flattened posterior articulating surface
• External tibial rotation and hyperpronated feet
  increase Q angle
• Family history

30
Patellar Subluxation and Dislocation

• Evaluative Findings
• Table 7-4, page 260
• Apprehension Test
• Box 7-8, page 261
• Radiographic examination
• Rule out MCL sprain
• Treatment
• Conservative vs. surgical

31
Patellar Tendinitis

• Insidious onset
• Jumping activities, running sports, weight
  lifting
• Acute onset
• Blow to tendon
• Repetitive motions on a biomechanically
  malaligned extensor mechanism can result in
  unequal loads on the extensor mechanism
• Microtearing of fibers

32
Patellar Tendinitis

• Most common site of pain inferior pole
• Pain at superior pole quadriceps tendinitis
  (jumpers knee)
• Evaluative Findings
• Table 7-5, page 262
• MRI may be useful
• Conservative vs. surgical treatment

33
Patellar Tendon Rupture

• Predisposing factors
• Rheumatoid arthritis, diabetes, lupus, chronic
  renal disease, gout
• Chronic inflammation of tendon
• Corticosteroid medications
• Tension developed within quadriceps unit
  overloads the patellar tendon, resulting in
  rupture in midsubstance or avulsion from patella
  or patellar tuberosity

34
Patellar Tendon Rupture

• Evaluative Findings
• Table 7-6, page 262
• No ligamentous stability tests should be
  performed until examined by physician
• Treatment
• Immediate immobilization and transport
• Surgical intervention within 7 to 10 days
• Rehabilitation to restore knee function full
  return to activity in 12 months

35
Patellar Bursitis

• Bursa inflamed secondary to
• Single traumatic blow
• Repeated low-intensity blows
• Overuse
• Infection (redness, warmth, refer to physician)
• Evaluative Findings
• Table 7-7, page 264
• Figure 7-11, page 263
• Treatment modify activity control inflammation

36
Synovial Plica

• Fold of the fibrous membrane that projects into
  joint cavity
• During maturation, folds are absorbed into
  capsule however, in majority of population, a
  thickened area or crease remains
• Remains asymptomatic until area is traumatized
• Most commonly affects medial joint capsule

37
Synovial Plica

• When symptomatic, plica loses elastic properties
  and alters biomechanics of patellar gliding
  mechanism
• Evaluative Findings
• Table 7-8, page 264
• Test for medial plica syndrome
• Box 7-9, page 265
• Stutter Test
• Box 7-10, page 266

38
Synovial Plica

• Confirmed through MRI
• Treatment
• Modify activity
• Control inflammatory response
• Strengthen VMO to lessen symptoms by reducing
  tensile forces placed on plica

39
Osgood-Schlatter Disease

• Adolescent inflammatory condition that strikes
  the tibial tuberositys growth plate where
  patellar tendon attached
• Onset due to repeated avulsion fractures of
  tendon from its attachment caused by rapid
  growth and/or increased quad strength
• Results in osteochondritis of tubercle

40
Osgood-Schlatter Disease

• Evaluative Findings
• Table 7-9, page 267
• Figure 7-12 page 266
• Conservative treatment by reducing activity,
  controlling inflammation
• Surgical intervention if conservative treatment
  fails

41
Sinding-Larsen-Johansson Disease

• Found at attachment of tendon into inferior
  patellar pole (or quad tendon at proximal pole)
• Caused by stress fracture or avulsion because of
  repetitive forces associated with running and
  jumping
• Affects males more often, ages 10-14 yrs

42
Sinding-Larsen-Johansson Disease

• Evaluative Findings
• Table 7-10, page 268
• Treatment
• Rest, immobilization
• Decrease inflammation
• Modalities, NSAIDs
• Stretching and strengthening
• May be symptomatic until maturation

43
Patellar Fracture

• Blunt trauma
• May rupture of bursa palpation reveals crepitus
  or false joint
• Figure 7-13, page 268
• Active knee extension and passive knee flexion
  produce severe pain
• Resisted knee extension cannot be performed due
  to pain

44
On-Field Evaluation of Patellofemoral Injuries

• Equipment considerations
• On-field History
• On-field Palpation
• On-field Functional Tests
• Willingness to move the involved limb
• Willingness to bear weight

45
Initial Management of On-Field Injuries

• Patellar Tendon Rupture
• Gross deformity, immediate loss of function
• Splint in extension and transport
• Patellar Dislocation
• Obvious deformity
• Reduction should not be attempted spontaneous
  reduction may occur
• Splint in position if not reduced, in extension
  if reduced transport
• Figure 7-14, page 270