PELVIC OBLIQUITY. Mohahad osman, MD Assist. prof. Zagazig University. Definition of Pelvic Obliquity ( PO).
Mohahad osman, MD
Assist. prof. Zagazig University
A- PO is failure of the pelvis to lie in a perfectly horizontal position in the frontal plane; ie; interspinous line is not perpendicular to midline of body provided that legs are parallel to midline of body.
B- 3-D definition : any fixed malalignment bet. Spine & pelvis, in frontal, sagittal, horizontal or all these 3 planes.
I- Mayer (1936) :
1- Functional / non-structural PO :
- present only when pt. stands with knees straight & no lift under foot & disappear on sitting & on recumbency w legs parallel to midline of body
- due to LLD.
2- Structural / fixed PO :
-persists in all positions & cannot be passively corrected.
-Aetiology: a- infrapelvic (hips) b- pelvic
c-suprapelvic ( spine) d- combined
II- Dubousset ( 1991) :
1- Regular PO : spine & pelvis in same directions of deformity.
2- Opposite PO : in opposite directions.
A- Congenital hip contracture:
1- cong. Abductor contracture
2- cong. Adduction contracture
B- neuromuscular hip contractures :
abd, add or both.
SUPRA-PELVIC FIXED PO.:
- in cong. or neuromuscular scoliosis
- not in idiopathic scoliosis ( curve not extend to pelvis )
Interferes w sitting, standing balance & walking.
B- 2ry. Deformities :
* spinal : L. scoliosis( cause / result) . Increased L. lordosis.
* hip : Abd / add contractures .
* knee : hyperextension on long side
* apparent LLD.
C- decubitus ulceration: ischial / G. trochanter on lower side.
* CARDIOPULMONARY FUNCTION
* Gait :
- short leg limp ( dipping gait)
- Trendlenburg gait
EXAM OF DEFORMITY :
a- Pelvic obliquity:
* Oblique pelvis : interspinous line is not perpendicular to midline of body provided that legs are parallel to midline of body
* functional PO.; present only when pt. stands with knees straight & no lift under foot & disappear on sitting & on recumbency w legs parallel to midline of body
* fixed PO. : persists in all positions & cannot be passively corrected
1- infra-pelvic; overcomed by swining legs to one side or other while recumbent.
2- supra-pelvic; never.
* trunk alignment : plumb line
* type of curve
* flexibility / rigidity of curve
* neurologic exam.
* clinical photographs.
C- Fixed hip def. : abd, add, flexion ,rotation
- Power - specific muscles ( hip / trunk) -sensation
- PO. - LLD ( app / true) - circumference.
SPECIAL TESTS :
- iliotibial band
- hip instability.
A- Pelvic obliquity :
* diagnosis of PO. :
- in frontal plane - 3-D
* Angle of PO: Osebold , 1982
A- Angle ( Cobb )
B- rotation ( pedicles displac.)
C- c rigidity : - side bending - traction - suspension
D- Torso decompensation: Osebold
E- Pt. maturation : Risser sign
2ry changes in hips
B- suspension XR
C- traction XR
* Biochemical ; ms dystrophy
TTT of PO is directed to the specific cause
Ttt of functional PO:
- by leg length balancing
- up to 3 cm LLD ; shoe lift
- > 20 cm LLD; orthosis
- 3-20 cm LLD; shortening, lengthening or both.
* correct bony def. or jt. Contracture 1st.
A- cong hip contractures:
- early ; stretching / traction and spica casting
- neglected ; surgical release & splinting.
B- Paralytic hip contractures ; surgical
- abd contracture by ;
1- soft tissue release ( prox & distal).
2- STR+ erector spinae transplant or
3- STR+ intertroch. femoral osteotomy ; > 3 y old, severe, 3-D
- add contracture ;
A- Abdominal fascial plastic operations
B- Muscle- tendon transplant operations
C- Spinal surgery.
Objective: correction of def. to the point at which pelvis is level & then fusion of spine & pelvis in that corrected position.
A- Post. Surgery only; if pelvis can be levelled by passive bending / traction
* Harrington sacral bar * Luque * recent segmental instrumentations
B- Combined ant. & post . Surgery ; if pelvis can not be levelled by passive bending / traction or deficient post. elements
* ant correction& fusion without instrumentation
* ant correction& fusion with instrumentation ( Dwyer system).
A- correct hip & knee def. 1st then spinal fusion, otherwise spinal def will recur [ Barr, 1950 & Turek, 1984]
B- Beaty ; when PO is moderate & L. scoliosis is fixed , correct scoliosis w instrumentation 1st.
TTT of PO that cannot be corrected by hip / spinal surgery
1- 2ry osseouship changes or 2ry arthritic changes in L spine rendering full correction impossible.
2- residual significant fixed PO [ 18 deg]
1- LL realigning to trunk by femoral osteotomy
2- post iliac osteotomy [ Lindseth,1978]; compensating pelvic def. placing isch tuberosities & acetabla in planes perpendicular to long axis of body
3- ischium excision; partial / complete