480ms
Updated: 3/25/2022

Direct Anterior Approach for THA on a Standard OR Table

TECHNIQUE STEPS
Preoperative Patient Care
Operative Techniques
D

Simulation

1

Cadaveric demonstration of surgical approach and therapeutic skill

2

Sawbones demonstration of proper instrumentation

E

Preoperative Plan

P

1

Radiographic Templating

  • Identify radiographic view, laterality, and calibrate image
  • Estimate preoperative leg length discrepancy attributable to the hip
  • create a horizontal reference line between the bases of both acetabular tear drops
  • create two lines perpendicular to the reference line, one to the base of each lesser trochanter
  • the difference between both perpendicular lines represents the preoperative leg length discrepancy attributable to the hip
  • Select desired acetabular component, size and position
  • Select desired femoral stem component, size and position
  • Select desired femoral head size and length
  • Record leg length discrepancy and component size for reference during the case
  • Make note of the need for specialized components as necessary
Pearls
  • The goals of templating are to estimate component size, and to restore leg length and offset by careful cup and stem positioning. It can be helpful to estimate the amount of acetabular medialization and appropriate neck cut location prior to surgery

2

Surgical walkthrough including description of basic anatomy, appropriate approach, and goals of therapeutic skills

3

Performs appropriate physical exam maneuvers under anesthesia

4

Description of potential complications and steps to avoid them

F

Room Preparation

1

Surgical Instrumentation

  • Confirm all necessary instruments and implants are available

2

Room Setup and Equipment

  • Either a regular or radiolucent surgical table is used based on surgeon preference
  • a regular table allows the end of the bed to be lowered as needed to assist with femoral exposure
  • a radiolucent table does not have rails or a base that may interfere with intraoperative fluoroscopy
  • Confirm large C-arm is available on the opposite side of the table
  • An extra Mayo stand should be available for positioning the contralateral limb

3

Patient Positioning

  • The patient is positioned supine with the head near the anesthesiologist
  • A rectangular gel pad is placed centered under the buttocks, with the ASIS at the top 1/3 of the pad
  • if using a regular table, the inferior aspect of the gel pad should be at the edge of the break
  • The patient should be at the lateral edge of the operative side of the table
  • The surgeon should verify that the patient’s shoulders, pelvis, and feet are all in line with the longitudinal axis of the table, and that the pelvis is level with the floor
  • The surgeon should assess limb lengths prior to prepping and draping by manually palpating both heels or medial malleoli
  • a Galleazzi test may also be used
  • The ipsilateral arm may be placed across the chest and secured in place with straps for better access to the femur, but may impede anesthesiology access to the airway
  • The ipsilateral arm board may be moved to the contralateral side at the foot of the bed, to allow for abduction of the contralateral limb if necessary

4

Surgical Preparation and Draping

  • Both lower extremities are prepped in the usual sterile fashion
  • Impervious stockinettes are placed on both legs and rolled up just proximal to the knee
  • A sterile down sheet is placed under both extremities to the buttocks
  • Sterile adhesive impervious drapes are used to isolate the operative hip from the groin to just proximal to the ASIS
  • Coban wraps are applied on each extremity from the toes to the knee
  • A bilateral extremity drape is placed over the feet and up to the knees bilaterally, and then the end is placed over the hips and given to anesthesia
  • A laminar flow curtain may be placed based on hospital protocols
  • Bandage scissors are used to cut an opening in the extremity drape centered over the surgical site
  • The team is positioned
  • the surgeon should stand at the incision
  • one assistant should stand on the operative side, just proximal to the surgeon
  • a second assistant should stand on the opposite side of the table
  • the scrub tech should be positioned behind the surgeon

5

Surgical Team Timeout

G

Incision and Approach

P

1

Identify Landmarks and Draw Incision

  • The ASIS should be palpated and marked from its inferior aspect
  • The incision begins approximately 2 fingerbreadths distal and lateral to the inferior aspect of the ASIS and continues for approximately 5 fingerbreadths distal and lateral pointing towards the fibular head
  • The exposed skin covered with an antimicrobial drape
Pearls
  • The incision should be distal to the inguinal crease in order to reduce the incidence of wound healing problems. The tensor fascia lata may be palpated through the skin to confirm appropriate incision location

2

Incision and Approach

  • The skin is incised with a scalpel from proximal to distal
  • Dissection is continued through the adipose tissue down to the fascia of the TFL, using fingers or retractors to place the tissue on tension
  • Superficial vessels are grasped and cauterized prior to fascial incision
  • The TFL fascia is cleaned bluntly with a sponge
  • The TFL may be identified by four signs:
  • translucent fascia: the red color of the TFL should be seen beneath the fascia
  • the muscular fibers should course distal and lateral
  • perforating vessels should be seen entering the fascia laterally
  • the fascia should separate from the muscle easily after being incised
Pearls
  • It is vital for the surgeon to be certain that the fascial incision is centered over the TFL. This should be confirmed by palpating the ASIS subcutaneously and making the fascial incision distal and lateral to it
  • Making the fascial incision medial to the ASIS endangers the lateral femoral cutaneous nerve, and may risk dissection into the improper interval, endangering the femoral neurovascular bundle and leading to catastrophic injury

3

Deep Dissection

  • The TFL fascia is incised over the TFL in line with its fibers, and then gently elevated off the muscle with a knife, hemostat, or Allis clamp
  • Blunt digital dissection is used to open the interval between the TFL and rectus femoris, and the “saddle” of the superior femoral neck is palpated with the surgeon’s finger
  • A blunt Cobra retractor is placed into the saddle of the superior femoral neck
  • A Hibbs retractor is placed to retract the rectus femoris medially
  • A sharp angled Hohmann retractor is placed in between the TFL and vastus lateralis, distal to the vastus ridge
  • The lateral femoral circumflex vessels are identified with a hemostat using blunt dissection and cauterized or ligated
  • The deep fascial incision is continued until pericapsular fat is visualized
  • A large bump is placed under the thigh to relax the rectus femoris and femoral vessels
  • A finger is used to palpate the inferior femoral neck under the rectus femoris, and a second blunt Cobra is placed from superolateral to inferomedial
  • care should be taken not to place the retractor through the vastus lateralis, and should be repositioned promptly if this occurs
  • a small vessel over the inferior capsule now often becomes visible and should be cauterized
  • A Cobb and rongeur are used to remove the pericapsular fat and visualize the capsule
  • A Cobb is used to elevate the rectus femoris off the anterior aspect of the capsule to the anterior acetabular rim and electrocautery is used to release 1cm of the indirect head of the rectus
  • A lighted retractor is placed just over the anterior acetabular rim and the Cobb is removed
  • The bump is removed from below the thigh
  • A capsulotomy or capsulectomy is performed based on surgeon preference, exposing the proximal femur from the acetabular rim to the intertrochanteric line, and taking care to skeletonize the saddle of the proximal femur with electrocautery and a rongeur
  • If a capsulotomy is performed, either a “T” or “L” shape is used from the intertrochanteric line to the anterior rim of the acetabulum, and tagging sutures should be used to aid in retraction
  • The Cobra retractors should be moved intra-articularly
Pearls
  • Ideally, the vessels will be located in the center of the incision. The vessels should always be present: if they are not found, it is critical for the surgeon to pause and confirm that dissection is proceeding through the proper interval. Typically two arteries and one vein may be identified. The vessels should be inspected again at the end of the procedure and re-cauterized as needed to avoid postoperative hematoma
  • The Cobb and anterior acetabular retractor should be placed with great care due to their proximity to the femoral neurovascular bundle
H

Femoral Neck Cut and Acetabular Exposure

P

1

Neck Cut

  • The neck cut location is marked with electrocautery based on the preoperative plan and implant chosen
  • typically, the cut begins at the base of saddle going inferior and medial perpendicular to the axis of the femoral neck
  • The neck is cut with a sagittal saw
  • A second, “napkin ring” cut may also be made approximately 5-10mm proximal to the neck cut in order to assist with femoral head removal
  • A flat osteotome is used to free the “napkin ring” of bone, and it is removed with a tenaculum
  • A corkscrew tipped power drill is placed into the center of the femoral head. Once the tip engages with the femoral head, all retractors are removed except the anterior lighted retractor, and the surgeon pulls back so that the head will spin and release the ligamentum teres
  • The drill is disengaged from the corkscrew tip while it remains in the femoral head, and a “T handle” grip is attached in order to gently remove the femoral head
Pearls
  • The surgeon should ensure that the neck cuts are complete so that the calcar is not fractured during femoral head removal
  • The surgeon should also ensure not to plunge excessively deep with the saw in order to avoid damaging the posterior greater trochanter, sciatic nerve, or posterior acetabular rim
  • Making the “napkin ring” cut prior to the final femoral neck cut may ensure that the bone being cut is always stabilized by the femoral shaft
  • Orienting the cut surface of the femoral head towards the cut surface of the femoral neck during removal may allow it to slide out gently and avoid fracture of the calcar

2

Acetabular Exposure

  • The lighted retractor is replaced anteriorly if necessary, just anterior to the labrum but under the remaining capsule
  • The assistant raises the operative leg, and a sharp bent Hohmann retractor is placed posterior to the acetabulum to retract the TFL and proximal femur
  • The inferior capsule by the TAL is incised with electrocautery if tight, and a blunt Cobra is placed just distal to the TAL
I

Acetabular Preparation and Component Implantation

P

1

Acetabular Preparation

  • The labrum and acetabular fat pad are removed with a Kocher and long-handled knife and electrocautery
  • A small reamer is used initially. A 44mm size is usually sufficient, but smaller ones may be necessary based on femoral head size. Either straight or offset reamer handles may be used
  • The first reamer is directed medially in the appropriate anteversion
  • the goal of the first reamer is to go down to, but not into the true acetabular floor
  • Subsequently larger reamers are used in the anticipated appropriate abduction and anteversion until punctate bleeding bone is seen circumferentially and the remaining cartilage is removed
  • The final reamer used is either the same size or 1mm smaller than the acetabular component used, based on component design
  • C-arm fluoroscopy is used to check for adequate medialization and reamer size
Pearls
  • Removing the entire fat pad will allow the surgeon to appreciate the depth of the true “floor” of the acetabulum
  • Disengaging the reamer basket from the handle while in the wound and then removing the basket with a Kocher may reduce soft-tissue trauma
  • The surgeon should take care to ensure appropriate reamer position. The natural tendency is to over-ream anteriorly due to the position of the femur and musculature. The surgeon should be especially wary of this in muscular patients

2

Acetabular Component Insertion

  • The cup is impacted into place and position confirmed with fluoroscopy
  • The screw holes are inspected to ensure the cup is seated completely against the bone.
  • The impactor handle is removed, and screws are drilled and placed as needed
  • The acetabular liner is aligned and impacted into place, then checked with a Freer or Penfield-4 instrument to ensure it is seated properly
  • Osteophytes are removed with an osteotome, curette, and rongeur to prevent extra-articular impingement
  • All retractors are removed
Pearls
  • Osteophytes are commonly found inferiorly and should be removed after liner insertion
  • When inserting the cup, one edge should be first located underneath the rim, and then the cup rotated into position before impaction
J

Femoral Exposure

P

1

Table-Mounted Hook Placement

  • The post is attached to edge of the surgical table at the inferior aspect of the incision, and the arm is attached
  • The hook is attached to the arm
  • The surgeon uses the hook to translate the proximal femur anterior and lateral, and the assistant secures the hook and arm into place
  • The surgeon manually palpates the lateral aspect of the proximal femoral shaft through the vests laterals
  • The hook is placed into the deep interval, then through the vastus lateralis, grasping the posterior aspect of the femur, and pushing across the linea aspera, ensuring the hook is directly contacting the bone
Pearls
  • Use of a table-mounted hook is optional, but greatly assists with femoral exposure in our practice

2

Femoral Releases

  • The contralateral foot is elevated onto a padded Mayo stand, just enough to allow the operative foot to pass below the contralateral thigh
  • The assistant adducts and externally rotates the surgical limb, bending the knee and passing the foot underneath the contralateral limb
  • A short-footed Mueller retractor is placed on the posterior-medial calcar
  • A long-footed Mueller retractor is placed between the abductors and greater trochanter
  • The superior capsule in between the femoral neck and greater trochanter should be released with electrocautery, gradually moving from the anterior to the posterior aspect of the trochanter
  • If using the table-mounted hook, the surgeon should periodically increase the tension on the hook as more tissues are released
  • If not using a table-mounted hook, the surgeon should translate the femur laterally, then distal and anterior with either their hand behind the thigh, or a bone hook inserted into the calcar
  • As more tissues are released, the assistants should gradually increase external rotation, adduction, and elevation of the femur
  • If using a standard OR table, the foot of the bed may be dropped as needed to increase femoral exposure
Pearls
  • The assistants are very important for femoral exposure. Holding the limb in adduction and external rotation is key for ensuring the surgeon is able to access the proximal femur adequately
  • The retractor over the greater trochanter should be held gently to avoid fracture.
  • It is critical to ensure that the posterior aspect of the greater trochanter does not become entrapped posterior to the acetabular component prior to elevation in order to avoid fracture
K

Femoral Preparation, Trialing, and Component Implantation

P

1

Femoral Preparation

  • The surgeon should ensure the proximal femur is exposed adequately prior to preparing the femur
  • A ball-tip probe may be inserted into the proximal femur and down into the femoral shaft in order to visualize proper broach trajectory and avoid perforating the femoral canal with broaches
  • A box osteotome or rasp is used to enlarge the opening in the appropriate orientation and anteversion
  • A rongeur may be used to remove remaining bone on the superior femoral neck to assist with proper broach positioning
  • The femur is sequentially broached using offset broach handles, making sure to lateralize to avoid varus positioning
Pearls
  • The posterior femoral neck is a reliable indicator of native femoral anteversion. However, a long neck cut may distort the perception of native anteversion

2

Trialing

  • A trial head is attached to the broach of the anticipated final size
  • The retractors are removed, the hook is disconnected from the arm but the hook is left in place posterior to the femur
  • The assistant brings the limb straight out of adduction/external rotation, and uses traction and internal rotation to locate the hip while the surgeon guides the trial head into the acetabular component with their fingers
  • C-arm fluoroscopy is used to assess proper broach size
  • Limb lengths are assessed manually by palpating the heels or malleoli
  • Anterior hip stability is checked by palpating the trial head while externally rotating the foot. Posterior hip stability may be checked by flexing and internally rotating the hip
  • The assistant dislocates the hip by applying traction and external rotation to the limb while the surgeon uses their fingers or a bone hook to guide the trial head out of the acetabular component
Pearls
  • The surgeon should always keep their fingers in contact with the trial head during dislocation and relocation to prevent it from disengaging from the broach and migrating into the abdomen
  • Due to parallax and distortion, an AP fluoroscopic image alone is relatively inaccurate for assessing limb length, offset, and acetabular abduction and anteversion

3

Femoral Stem Insertion

  • The proximal femur is re-exposed, the broach removed, and the final stem is placed
  • A trial head is re-applied, the hip is relocated, and the limb lengths reassessed
  • The hip is dislocated and the proximal femur is exposed
  • The trunnion is cleaned with a sponge, the final head is chosen based on limb-length assessment, and is then placed and impacted
  • The hip is relocated and a final fluoroscopic image is taken
N

Wound Closure

1

Irrigation and Hemostasis

  • A Hibbs retractor is used to retract the rectus medially
  • The Hueter interval is inspected and hemostasis is achieved, making sure to re-inspect the lateral femoral circumflex vessels for recurrent bleeding
  • The wound is irrigated
  • Local anesthetic is administered in the deep tissues

2

Deep Closure

  • The capsule is repaired if capsulotomy is performed
  • The tensor fascia is closed with running #1 absorbable suture

3

Superficial Closure

  • The subcutaneous layer is closed with interrupted 2-0 absorbable suture
  • An additional running 3-0 absorbable monofilament may be used per surgeon preference

4

Dressing

  • A sterile, watertight dressing is applied
Postoperative Patient Care
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