BASIC ARTHROPLASTY WORKSHOP

ARTHROCON

HIP SURGICAL ANATOMY & APPROCHES

OP LAKHWANI

Associate Professor, Orthopedics Surgery,

ESIC – Postgraduate Institute Of Medical Sciences & Research, ESI Hospital, New Delhi

SURGICAL ANATOMY

HIP Ball & socket joint

6 degree movements

Hip inclined plane shearing forces.

Cement – strong compression than shearing forces

Femur > Acetabulum wear

DISSECTION

Superior and

inferior Gluteal

Nerve

ACETABULUM

Anterior - iliopubic eminence

Superior - strong thick

Posterior - Stability

Medial - Tear drop

ilioischial line

Inferior - deficient, TAL

ACETABULUM EXPOSORE

360 degree exposureSuperior

large smooth Steinman pin to

retract abductor

Anterior

Iliopubic eminence place a

curved pointed retractor

translate the femur anteriorly.

Difficult exposure - check distal

insertion of the gluteus maximus

tendon on the femur and the retained

superior capsule and tendon of the

reflected proximal rectus femoris have

been adequately released.

ACETABULUM EXPOSURE

Inferior - a cobra retractor at

transverse acetabular

ligament.

Posterior - wide

Hohman- type

retractor into the

tuberosity of the

ischium. Take care

not place posterior

acetabular

wall and into the

acetabular fossa.

ACETABULUM EXPOSURE

Remove remnants of acetabular labrum,

osteophyts from the acetabular brim. Next

remove the pulvinar (fibrofatty material

medially).

avoid the ascending branch of the

obturator artery when removing the

inferior pulvinar near the transverse

acetabular ligament.

medial osteophyte is present, the pulvinar

may not visible. This means that

acetabular reaming needs to proceed

medially down to the true medial aspect of

the acetabulum.

Acetabular Fixation Safe Area

The successful total hip arthroplasty -

fixation and stability with appropriate

component positioning.

Restore center of rotation, leg length, and

offset, Inclination, Anteversion,

POSITIONING OF ACETABULUM CUP

Orientation -10 – 300 of anteversion, 40 - 500

abduction

Position – flexion deformity , lumbar lardosis – ant Pelvic tilt

Inclination - targeted to 40° ± 5°

Combined anteversioncustomized according to femur to combined

anteversion of 30° to 45° (with 5° margin of error for safe zone of 25° to 50°), lower r men with low femoral anteversion, and higher women .

Center of rotation - Reaming medially is done to the cotyloid notch which medializes the center of rotation 3 to 6 mm; removal of the lunate bone and formation of a hemisphere moves the centerof rotation cephalad to 5 mm.

Surface land marks - ASIS, iliac tubercle, Shoulder Patient positioning, Greater trochanter

Inter conlar axis patella

Positional guide

Intra-articular landmarks

orient the inferior most portion of the cup at the level of the teardrop and margin at TAL, anterior margin at level of ant wall the posterior edge of the cup at the level of the ischium.posterior superior edge may over hang mm anterior.

,

Notch Acetabular angle - lies parallel to acetabular opening hence aligning the cup along sciatic notch acetabular angle reproduces normal anteversion aligning socket towards notch add 10-15 0

additional antevesion

Cup stability – combined anteversion

anatomy of acetabulum not permit anteversion of cup

beyond 30°. Abn anteversion , modular stem, or

cementing .

limits 25° to 45° anterior dislocations if more than 50°

combined anteversion

lower in men because femoral anteversion.7° in women in

our study.

To accomplish the combined anteversion requires femoral

preparation first so the cup can be adjusted to the stem.

The combined anteversion test assesses component

positioning With the limb in 10 adduction, the femoral head

should be coplanar with the face of the acetabulum. when

the limb is internally rotated.

FEMORAL PREPERATION - LIMB LENGTH

Measure length before dislocation

and compare after

Offset

Cut – level , Direction, anteversion

Anteversionpatella, transcondylar

axis

Measuring the distance from the lesser

trochanter to the center of the femoral

head and reproducing this dimension

post-arthroplasty will help to minimize

leg length discrepancies.

Leg length

The lesser trochanter should not impinge on the ischium in full extension and should be one fingerbreadth above the tip of the ischium for correct leg length.

In external rotation and abduction, the metal neck should not impinge on the cup nor the greater trochanter on the posterior ilium. In flexion and internal rotation, the metal

neck should not impinge on the anterior-superior cup or the greater trochanter on the anterior ilium.

Several tests are available to assess the quality of the arthroplasty including the combined anteversiontest, the shuck test, the Ober test, and the range-of-motion test.

Failure to restore component offset may result in instability, limp, and excessive wear. Increasing the offset may lead to pain, stiffness, and functional leg lengthening due to abduction contracture.

SURGICAL APPROACEHS

Surgeon driven

Expertise

Training

Personal philosophy

95% case primary hip can be operated with one approach hence said master the one approach

Situation - Altered anatomy

Previous surgery

Pt related factors

Preference one over other

Internervous Intermuscular plane Least interfering Neurovacular structure and tissue trauma.

Classic ilitibial band Gluteus med Key Muscle, Essentially lateral differ only in so far as they may be slightly anterior or posterior to the lateral plane. The anatomical structure which determines the question is theGlutus med tensor fascia Approach in front of this muscle antero-lateral: if behind, then postelo-late'al.

Trans trocha main door Charnley

AnteroL

PosteroL

SURGICAL APPROACEHS

Postero lateral Approach

POSITION - lateral decubitus

INSCISION

advancing anteriorly moore to gibson.

Posterior border of the greater trochanter,

and extends proximally from the level of the

vastus tubercle for 10 cm cephalad.

STEPS

Gluteus maximus incised 6 to 8 cm along

the posterior border greater trochanter.

external rotators and the posterior capsule

with the leg in internal rotation as a single

flap just proximal to the quadratus femoris

In flexible hips, the Piriformis tendon+/-

preserved and an L-shaped incision one arm

parallel to the piriformis tendon.

The hip is dislocated third incision is of the

inferior medial capsule, which is incised

from the anterior femur to the acetabulum

through the transverse acetabular ligament.

Postero lateral Approach…. Decrease dislocation – tagging before

release External rotator repair

Larger head

Adv – excellent view acetabulum and femur, risk of sciatic nerve, dislocation – post soft tissue repair - Transosseusnonabsorbable suture to repair the anterior released fiber of G medius,

easier to make these drill holes prior to reducing the hip

advantage of dependent drainage, extensile

Avoid abductor damage Ext rotator release – dislocation , Sciatic nerve

Tight hips may require 1 cms more release of G medius at anterior superior corner of GT.

difficult dislocation require ITB release and allow to slip posterior to GT.

Ant Lateral ApproachPOSITION - Supine/ LateralINCISION - Centered over greater anterior

aspect of Greater Trochanter.STEPS

-Split ITB distally and G.Max proximally.- Exposing – Vastus lateralis and G medius- Idetify position of head , Tip of greater

trochanter , Slit Vastus lateralis and G.Mediusat anterior 1/3 maintain continuty of anterior sleeve

Differ in manner and effect of releasing Gluteus medius and vastus lateralis insertion and protection of Superior Gluteal nerve and vessels.

Flexible hip, Less risk of avn head preserving surgery Limitation – superior gluteal nerve and branches , imited posterior collumn access, ant dislocation

Trochanter overhang – varus positioning of implant

Safe limit area

Surgical Approaches

Trans troch

Approach Dislocation HO Limp

PosterL ++ + +

Antero L + ++ ++

Trans troch + + +

STABILITY CHECK

Assess component stability. Examine the hip at: 90 degrees of hip flexion-simulating sitting;

flexion, adduction and internal rotation simulating the fetal sleeping position; and

in extension, abduction and external rotation,

assessing for any evidence of anterior instability.