Hip

1
Hip
2
Fractures

• Pelvic fx 20 MVA - 15,300/yr in U.S.
• Proximal hip fx - 250,000/yr in U.S.
• 4.5/100 in people gt 70 y.o.

3
Mechanisms

• Femoral neck fx
• Trauma 20 falls
• Lateral Rotation of LE w/ fall backwards
• Stress fx

4
Mechanisms

• Impact 20 fall ?subsequent fx
• Fracture precipitates fall
• Hip fx occur in lt 5 of falls
• Inverse relationship between hip fx and BMI

5
Mechanisms
6
Mechanisms
7
Mechanisms
8
Understanding the Mechanisms

• Bone quality
• Muscular strength
• Soft tissue characteristics
• Neuromuscular coordination
• Rare

9
Lever-Arm Dysfunction

• Bony lever arms are abnormal due to abnormal bone
  development
• Cerebral Palsy

10
Lever-Arm Dysfunction

• Normal bone growth dependent on
• Genetics
• Adequate nutrition
• Adequate dynamic forces
• Bone deforms according to the
• Forces placed on it
• Lack of forces placed on it

11
Angle of Inclination

• Infancy 1500
• Adult - 1250

12
Coxa Valga
G. Medius
G. Medius
G. Medius
13
Femoral Torsion

• Approximately 400 - 450 (anteverted) in newborn
• 150 in the adult

14
Femoral Torsion
Anteversion
Retroversion
15
Femoral Anteversion

• Why in CP?
• Delayed standing
• Abnormal external forces 20 ? tone
• ? ligamentous laxity
• 45 - 650

16
Femoral Anteversion

• Manifestations
• Hip abductor weakness resulting from moment arm
  out of plane
• Anterior pelvic tilt ? maintain femoral head
  coverage
• ? knee extension moment ? Hip IR, Knee flexion
  and valgus

17
Femoral Anteversion

• Manifestations
• Internal foot progression angle ? ? rockers
• Abnormal patellafemoral mechanics

18
Dislocation

• High forces
• Usually associate with acetabular and/or femoral
  fx
• Direct - trochanter
• Indirect - foot or flexed knee (dashboard
  dislocation)

19
Dislocation

• Anterior (10-20 of hip dislocations)
• Forcible abduction
• Abduction w/ flexion ER
• obturator-type anterior dislocation
• Abduction w/ extension
• pubic- or iliac-type dislocation

20
Dislocation

• ? Retroversion ? ? risk of dislocation
• Congenital hip dislocation (hip dysplasia)

21
Osteoarthritis/DJD

• Most common joint disorder
• 20 inflammation
• softening of cartilage 20 ? proteoglycan
• thinning ? pitting, fissuring, ulceration
• subchondral bone necrosis
• osteophyte formation

22
Osteoarthritis/DJD

• Graded
• joint space narrowing
• osteophyte formation
• sclerosis
• joint deformity

23
Osteoarthritis/DJD

• Strongly associated w/
• Onset
• MTP
• wrist and spine
• toe IPs and 1st carpometacarpal
• tibiofemoral
• hip

24
Osteoarthritis/DJD

• Development
• predisposition
• joint abnormality
• mechanical loading
• use

25
Osteoarthritis/DJD

• Primary - idiopathic
• Secondary
• trauma
• metabolic disorders
• CPDD
• DISH

26
Osteoarthritis/DJD

• Biomechanical
• Biochemical
• Inflammatory
• Immunological

27
Osteoarthritis/DJD

• Biomechanical
• trauma
• overuse - occupation
• obesity

28
Muscle Strain

• Occurs during
• forced lengthening/eccentric
• - control
• - decelerate high velocity movements
• compromised muscle ? ? ability to absorb energy

29
Muscle Strain

• Muscle compromise
• fatigue
• predisposing factors
• - muscle imbalance
• - inflexibility
• - insufficient warm-up

30
Hamstring Strain

• Susceptible
• two-joint muscles
• sprinters
• - late swing
• - early stance
• - high proportion of FT

31
Hamstring Strain

• Most common
• proximal
• biceps femoris long head
• myotendinous junction
• - actual interface (folding) ? more shearing
  than tensile
• - limited extensibility