THA Direct Anterior Approach

Authors:

Planning

B

Preoperative Plan

1

Radiographic templating

  • In general templating the case pre-operatively is helpful when planning the surgery. Of not it is more difficult to lengthen a patient through the direct anterior approach then say a posterior approach so this must be considered when planning the surgery.

2

Execute surgical walkthrough

  • describes the steps of the procedure to the attending prior to the start of the case
  • describe potential complications and steps to avoid them
C

Room Preparation

1

Surgical Instrumentation

  • total hip replacement system of choice

2

Room setup patient positioning and equipment

  • required operative table
  • Hana table
  • C-arm on opposite side of table with scrub (can help hold anterior retractors).
  • put patient to sleep on stretcher
  • put webril and coban, SCDs and TEDs on both legs then place in boots
  • transfer to HANA table
  • place peroneal post (wrapped in webril) then slide patient all the way down against post
  • place boots in foot holders
  • contralateral arm on arm board, ipsilateral arm across body sandwiched in pink foam and taped out of way
  • Arch table
  • make sure table allows bottom portion to be removed (not just bent down) ~36 inches from floor to rail
  • slide table all the way down on base to allow C-arm to get under from opposite side of table
  • put webril and coban on operative foot, SCD and TED on both legs
  • ARCH should be at a height so the heel of boot is at the top level of the padding on the bed
  • have someone hold both legs and remove bottom portion of bed
  • place peroneal post (wrapped in webril) on ipsilateral rail, move as proximal as possible and tighten
  • slide patient all the way down against post. Put rail extension on contralateral side, place well leg holder and put leg in neutral position to slight ER so that lesser troch is visible
  • slide ARCH in from below, make sure it is directly in-line w/ leg, put leg in boot and tighten straps
  • raise/lower ARCH base so leg is neutral
  • make sure GROSS traction is in the middle of rail and tighten
  • tighten base of ARCH
  • contralateral arm on arm board
  • ipsilateral arm across body sandwiched in pink foam and taped out of way.
  • Tableless
  • will usually need a third assistant on opposite side of table to aid in leg positioning
  • can break the legs of the table down to allow extension of the operative leg.

Technique

D

Incision & Superficial Dissection

1

Identify anatomic landmarks

  • Incision starts 2-3cm posterior to ASIS and ~2cm distal to ASIS, extends about 30 degrees posteriorly (towards fibular head/later femoral condyle), about 10-12 cm long

2

Smith Peterson Approach

3

Identify internervous plane

  • Superficial internervous plane - sartorius(femoral n.)/tensor fasciae latae (sup. gluteal n.)
  • Smith Peterson Approach
  • Deep internervous plane - rectus femoris(femoral n.)/gluteus medius (sup. gluteal n.)

4

Modified Hueter Approach

E

Deep Dissection to Anterior Capsule

1

Modified Hueter Approach

  • Deep internervous plane - rectus femoris(femoral n.)/gluteus medius (sup. gluteal n.)
  • this is the same internervous planes as Smith Peterson approach but instead the dissection is carried down through the fascial compartment of the tensor fasciae latae
  • this will decrease the risk to the lateral femoral cutaneous nerve

2

Get through fat to fascia of TFL,

3

Make incision through the TFL

  • fascial incision will end up being middle ⅓ of TFL.
  • be sure to split subcutaneous tissues up to the pelvis.

4

Ensure incision in proper anatomic structure

  • make nick in fascia to ensure fibers are running in correct orientation to be TFL and not abductors.

5

Open up the fascia

  • open fascia entire length up to pelvis
  • put Alice on anterior flap, cobb or finger dissect TFL posteriorly.
  • feel for soft spot over lateral femoral neck,
  • open deep TFL fascia here w/ bovie,

6

Place retractor

  • place long double bent narrow homan or Cobra retractor at 45 degrees (handle toward contralateral shoulder)

7

Identify the vastus lateralis

  • split tissue up onto pelvis
  • split fascia distally and find vastus lateralis
  • from vastus work proximally to find vessels

8

Identify vessels

  • place vessels/vascular leash cross field in middle of incision or toward distal end just proximal to vastus,
  • use bovie to feather down to them
  • occasionally the vessels will be deep to fascia instead of superficial
  • usually thin fascial layer above vessels and deep precapsular fascia deep to vessels.
  • use 2 tonsils to isolate and clamp vessels (tips facing each other), transect in middle with bovie/scissor. 0 Silk ties or cauterize each end

9

Identify the femoral neck

  • the Inferior femoral neck just anterior to vastus lateralis
  • place a cobra retractor here
  • handle towards contralateral knee

10

Expose the capsule

  • when completely through deep TFL fascia, remove triangle of pre-capsular fat (b/t TFL, rectus, vastus lateralis).
  • use cobb to elevate rectus off anterior capsule
  • start inferior neck and distal and work proximal onto acetabulum
  • don’t release origin.
  • can flex hip 20o to take tension off rectus but usually not necessary

11

Perform capsulotomy

  • place MIS anterior retractor under rectus, over anterior rim/column of acetabulum.
  • make sure you are on capsule and no muscle is under retractor
  • neurovascular bundle is on the other side of the rectus.
  • perform “T” or "L" capsulotomy along intertrochanteric line and up femoral neck to anterior rim of acetabulum. Can tag capsule for later repair of excise it.
  • move retractors to inside of capsule
  • externally rotate leg to 40-50 degrees
F

Femoral Neck Cut and Acetabular Exposure

1

Identify landmarks of the femoral neck

  • useful landmarks include the shoulder of the neck superiorly, head/neck junction and lesser trochanter

2

Identify location of the femoral neck cut

  • you can measure the distance above the lesser trochanter using a template placed at the shoulder of the neck or drill hole in neck where you think cut should be
  • place schnit in hole and take X-ray.
  • usually if you find the shoulder of the femoral neck and draw a line just below the head neck junction that is a good estimate of where your cut should be.
  • be careful if there is a large CAM lesion as this can distort the anatomy and should be removed first.

3

Make the femoral neck cut

  • start on calcar side, be careful not to notch posterior troch, lever on saw blade to complete cut. MAKE SURE TO CUT MEDIAL CALCAR
  • if neck is not completely cut it is most likely medial calcar.
  • can perform "napkin ring" double osteotomy to remove a piece of bone which may make head removal easier.
  • place traction on the leg to aid in head removal
  • some will place traction on the leg and dislocate the hip prior to cutting the neck which helps in releasing the soft tissue from the hip
  • corkscrew on power up femoral neck
  • if head is stuck in actetabulum 2/2 large osteophyte or ankylosed hip, put on T handle and spin head to expose beak of lateral neck and trim w/ rongeur to avoid trauma to TFL when removing
  • release any remaining attached capsule

4

Expose the acetabulum

  • maintain leg in ~50o ER and traction
  • If capsule preserved can place self retainer (ie Gelpie) inside capsular flaps
  • replace anterior MIS retractor under rectus to hold self retainer in place
  • place cobra over posterior column at capsular/labral junction around 7-8 o’clock for right hip
  • may need to use hibbs to retract capsule to identify capsular/labral junction
  • remove labrum, obvious osteophyte, and define true floor (condyloid fossa usually points toward perineal post) and debulk transverse acetabular ligament if necessary for exposure
G

Acetabular Preparation and Acetabular Component Implantation

1

Ream the acetabulum

  • select reamer size based on template and size of resected head
  • ballpark 3mm below templated size OR odd # larger than measured femoral head
  • may need an offset reamer to avoid levering on femoral neck
  • start reaming medially first, tendency is to ream up into dome too much and not get to medial wall
  • final reamer position is pointing toward ipsilateral SI joint
  • most systems under ream by 1mm to press fit a cup
  • use C-arm to check position of reamer

2

Place the cup

  • impact cup, palpate to ensure no anterior overhang, check amount of lateral overhang and confirm w/ template
  • use C-arm to confirm position of cup
  • remove inserter and look through hole to ensure cup down completely
  • use secondary impactor as needed
  • place screws if desired
  • orient drill slightly more flat (less anteverted) than it was for cup insertion
  • place poly insert
  • use osteotome/rongeur for osteophytes
H

Femoral Exposure

1

Expose the femur

  • release traction on femur.
  • consider removing capsular flaps along acetabular rim or continue to save for later closure.
  • goal is maximal external rotation of femur (120-130o)
  • this is achieved by releasing the posterior caspule from the femoral neck and releasing the capsule up on to the posterior aspect of the trochanter with the goal of preserving the piriformis and short external rotators attachment
  • the leg operator should count out ER as they begin to rotate the leg and stop when it is tight with the goal being a vertically oriented calcar

2

Place femur into wound

  • translate the femur laterally during ER and releasing the tissue to avoid the greater trochanter from impinging on the pelvis
  • place a retractor around the posterior medial femoral neck to retract the medial tissues and another retractor can be placed around the anterior femur and over the trochanter to help elevate and expose the femur
I

Femoral Preparation, Trialing, and Component Implantation

1

Prepare the femur

  • prepare the femur using the appropriate broaches
  • in general with each broach you want to assure you are lateralizing the broach and maintaining the appropriate anteversion
  • the tendency is to over antevert which can increase you chance for a post-operative dislocation

2

Place the trial implant

  • place a trial head and neck in accordance with your pre-op plan/template
  • reduce the hip
  • confirm position
  • use C arm to confirm the position and size of your broach as well as your leg length
  • leg length can be evaluated but using a long rod and comparing the lesser trochanters on an AP pelvis image
  • dislocate the hip
  • reapply traction and externally rotated the leg
  • may need a bone hook around the femoral neck
  • with the hip dislocated remove the trial head and neck
  • release the traction now, externally rotated back to ~130, extend the leg to the floor and adduct to expose the femur again

3

Place final implant

  • place your retractors and reassess the broach to assure there was no subsidence and that the broach remains stable
  • remove broach and place femoral component
  • trial the hip again to fine tune length through the femoral head or place the real head if you were comfortable with you implant position compared to the broach position

4

Reduce the hip as above

J

Wound Closure

1

Irrigation, hemostasis, and drain

  • irrigate wound

2

Deep closure

  • repair capsule if preserved
  • close fascia over tensor

3

Superficial closure

  • close subcutaneous layers
  • consider a subcuticular running suture for the skin with skin glue
  • these wounds sometimes have difficulty healing secondary to their position near the groin.

4

Dressing and immediate immobilization

  • soft dressings over incision

Patient Care

K

Preoperative H & P

1

Perform basic medical and orthopaedic history and physical

  • document neurovascular status
  • identify medical co-morbidities that might impact surgical treatment
  • screen medical studies to identify and contraindications for surgery
  • ensure all studies are required to proceed with surgical intervention

2

Order basic imaging studies

  • AP/Lateral of the hip
  • AP pelvis

3

Perform operative consent

  • describe complications of surgery including
  • Lateral femoral cutaneous nerve palsy
  • infection
  • dislocation
L

Perioperative Inpatient Management

1

Write comprehensive admission orders

  • IV fluids
  • wound care
  • orders and interprets basic imaging studies
  • inpatient physical therapy
  • advance diet as tolerated
  • DVT prophylaxis
  • pain meds
  • foley out when ambulating
  • appropriate medical management and medical consultation

2

Discharges patient appropriately

  • pain meds
  • outpatient PT
  • wound care
  • schedule follow up in 2 weeks
M

Outpatient Evaluation and Treatment

1

Obtain focused history and performs focused exam

  • concomitant and associated orthopaedic injuries
  • assess for risk of thromboemblotic disease
  • differential diagnosis and physical exam tests

2

Orders and interprets required diagnostic studies

  • order and interpret AP pelvis, AP and lateral of the hip

3

Prescribes and manages nonoperative treatment

  • physical therapy
  • guides trial of medical managment
  • Nsaids
  • attempts trial of physical therapy
  • injections
  • activity modification

4

Makes informed decision to proceed with operative treatment

  • documents failure of nonoperative management
  • describes accepted indications and contraindications for surgical intervention

5

Provides post-operative management and rehabilitation

  • postop: 2-3 week postoperative Visit
  • wound check
  • check radiographs
  • diagnose and management of early complications
  • physical therapy
  • weight bearing as tolerated
  • no dislocation precautions although some will advise against bridging.
  • advise patients/therapist to avoid repetitive strengthening exercises of hip flexors (such as supine SLR) to minimize psoas and rectus pain until surgical inflammation completely resolved
  • postop: ~ 3 month postoperative visit
  • check radiograph
  • diagnosis and management of late complications
  • postop: 1 year postoperative visit
N

Advanced Patient Evaluation and Treatment

1

Appropriately orders and interprets advanced imaging studies

  • MRI
  • CT
  • nuclear medicine imaging
  • advanced radiographs views

2

Appropriately recommends surgical intervention

3

Modifies and adjusts post-operative treatment plan as needed

4

Provides prophylaxis and manages thromboemblotic disease

O

Complex Patient Evaluation and Treatment

1

Develops unique, complex post-operative management plans

 

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