1. Opening slide – stress the “muscle sparing” part.
The Zimmer® MIS™ Anterolateral Hip Procedure A Muscle-Sparing Approach to THA

2. Objectives
Review the objectives for the course in order to set expectations for the participants.
Ask the participants if they have any questions on the objectives.
Discuss the history of minimally invasive surgery in terms of evolution, definitions, approaches, and classification schemes
Identify the unique characteristics of the Zimmer MIS Anterolateral THA procedure
Discuss in detail the stages and key elements of the Zimmer MIS Anterolateral THA surgical procedure
Define the Five Acts of leg positioning and describe how they relate to the various stages of the surgical procedure

3. Objectives (cont.)
Objectives continued.
Ask for questions.
Discuss clinical data obtained from procedure to date
Define the advantages and disadvantages of the Zimmer MIS Anterolateral THA procedure as they relate to THA in general
Identify and discuss key concerns in the overall continuum of care related to the Zimmer MIS Anterolateral THA procedure

4. This section will discuss the history of minimally invasive surgery as it relates to medical advances as well as to THA.
Minimally Invasive Surgery: History, Evolution, Definitions, and Approaches

5. Minimally Invasive Surgery: Evolution in THA Procedures
Advent of modern THA in 60s/70s with large incisions – better view with larger incision.
Time has shown a decrease not only in the size of incision, but in the trauma to soft tissue.
Transition to next slide is from history to evolution throughout medicine.
Maximally invasive 60s/70s
Moderately invasive 80s/90s
Minimally invasive Turn of the century

6. Maximally Invasive Surgery
Straightforward – benefits of traditional approach to total joint arthroplasty.
Typically Provides:
Wide Exposure
Neurovascular protection
Confident implant placement
With this incision I can do every hip:
I can expose it,
I can see it,
I can teach it
(C. S. Ranawat, CCJR 2003)

7. What is the Minimally Invasive THA?
Content here is more rhetorical.
Meant to stimulate thought process as to why a surgeon would want to venture into minimally invasive procedures.
Can ask participants what they think to generate early discussion in session.
Key point: length of incision is not important…lack of tissue trauma is.
Too small of an incision can actually result in more tissue trauma.
Length of Incision?
Length of capsule incision.
Amount of muscle trauma!
Amount of bone loss!

8. Minimally Invasive THA Classification
Historically, the various approaches have been classified by the inventor’s name.
This does not necessarily provide for a concise, systematic method of determining what is occurring surgically.
Eponymous
Modified Watson Jones
Modified Smith Peterson
Modified Moore
Keggi/Mears/Röttinger
…does not connote much meaning

9. Minimally Invasive THA Classification
A better way to classify the various THA approaches is by these categories.
Briefly cover each of these characteristics
Let participants know you will cover each of these in detail on subsequent slides.
Proposal
Direction
Number of incisions
Method of deep dissection

10. Minimally Invasive THA Classification
Glut Med represents a dividing point between anterior and posterior minimally invasive surgery approaches.
Anterior approaches are anterior to medius, posterior behind, and lateral through the medius.
Transition to next slide on number of incisions.
Direction is the key
Gluteus Medius is the signpost
Anterior
Anterolateral
Lateral
Posterior

11. Minimally Invasive THA Classification
In addition to approach direction, minimally invasive THA procedures can be further classified by number of incisions.
Cover each of these briefly.
Key message is difference between single and dual-incision approaches.
Literature has even defined a three-incision approach (Keggi).
Number of incisions
Single Incision – acetabular/femoral preparation through one incision
Two incisions – acetabular preparation through anterior incision and femur preparation through posterior incision

12. Minimally Invasive Surgery THA
Traditional and mini Direct lateral/Anterolateral procedures divide or split muscles, while others spare by going around the entire muscle.
Key: Anterolateral is a muscle-sparing approach.
Method of Deep Dissection is key
Do you divide or go between the muscles and tendons?
Traditional – Cut
Mini Anterolateral – Cut less
MIS Anterolateral – Spare
Spare: to refrain from doing harm
Merriam Webster’s Dictionary

13. Minimally Invasive THA Classification
To further expand upon this notion, here is a breakdown of muscle-splitting vs. muscle-sparing.
Any questions?
Method of Deep Dissection
Anterior - Muscle Sparing
Anterolateral - Muscle Sparing
Lateral - Muscle Cutting
Posterior - Muscle Cutting
Two-incision - Muscle Sparing

14. Introduction to the Zimmer MIS Anterolateral THA Procedure
Transition slide to preface surgical technique section.
Covers
Introduction to the Zimmer MIS Anterolateral THA Procedure

15. The MIS Anterolateral Approach
Cover key bullet points.
Identify appropriate location of interval.
We’ll discuss how to identify this interval when we get to the surgical technique portion of the program.
Gluteus Medius
A single incision
Muscle sparing approach to the hip
Interval between the anterior border of the gluteus medius and the posterior border of tensor fascia lata.
Minimally invasive modification conceived by Heinz Röttinger, M.D. from the Orthopädische Chirurgie München (O.C.M.) Munich, Germany in 2003
Tensor Fascia Lata

16. The MIS Anterolateral Approach – Overview
Features and benefits the AL procedure.
Precursor to the surgical procedure – each of these will be covered in greater detail.
(This slide is not meant as a comparison to other procedures)
Interval between Gluteus Medius and Tensor Fascia Lata
No division of any muscle or tendon
Acetabulum and femur directly visualized
8-10 cm incision
Posterior capsule intact → lower risk of dislocation

17. The MIS Anterolateral Approach – Overview (cont.)
Continuation of previous slide’s material.
(Again, no comparison to other procedures).
Reinforces advantages of AL approach.
Extensile - bail out is full Watson Jones exposure
Acceptable learning curve
Familiar lateral positioning
Clear of neurovascular hazards
Compatible with most contemporary Zimmer implants

18. The MIS Anterolateral Key Principles
Before delving into the full surgical technique, it is important to understand the three key principles of the AL approach that help lead to success.
Each of these will be covered in detail on subsequent slides.
This is more of a transition slide into the full surgical procedure section.
Identification of interval
Anatomical referencing
Retraction and mobile window
Femoral exposure/Extensibility of capsular incision
Leg positioning

19. MIS Anterolateral Procedure
Procedure’s success is predicated on leg position.
These five acts of leg positioning represent the crucial aspects of the procedure.
We cannot overemphasize the importance of this concept.
Cover each and state you will go into detail on following slides.
We will review these in greater detail after you have been exposed to the individual steps of the surgical procedure.
The Five Leg Positions
Skin and Capsular Incisions/Closure
Transcapital Neck Cut
Definitive Neck Cut
Acetabulum
Femur

20. Leg Positioning Incisions Femoral Side Acetabular Side 1st Femoral Cut
Importance of leg position.
Assistant can work with you or against you.
Incisions
Femoral Side
Acetabular Side
1st Femoral Cut
Definitive Osteotomy

21. Surgical Technique for the Zimmer MIS Anterolateral THA Procedure
1. Transition slide.
Surgical Technique for the Zimmer MIS Anterolateral THA Procedure

22. The MIS Anterolateral Surgical Considerations
Discuss the content here as the main components of the surgical procedure.
You can read them for yourselves, but each of these is a different aspect of the procedure.
Pre-op Templating
Table
Positioning
Draping
Incision
Dissection
Capsule
Referencing (intra-operative measurements)
Neck Osteotomies
Acetabulum
Femur

23. Templating Measure down from the “Saddle” Other anatomical references
Key: saddle – dependable and repeatable landmark.
Measure down from the “Saddle”
Other anatomical references
Lesser trochanter can usually be palpated for cross reference
“Saddle”
Greater Trochanter
Lesser Trochanter
Overall pre-operative planning for the MIS Anterolateral Approach includes:
Determining leg length differential (LLD).
Identifying femoral offset issues.
Determining correct acetabular and femoral component sizes.
Assessing positioning of the femoral neck cut.

24. Surgical Technique Table set up Trumpf Jupiter table or Maquet
Must be able to drop the leg off of the table for femoral preparation.
These are suggested table types/modifications.
Others may exist.
Table set up
Trumpf Jupiter table or Maquet
Skytron table attachments
Local custom modification
Make sure padding is sufficient under lower leg to avoid pressure problems.
Must get used to anterior position if you have been performing THA from posterior side of patient.

25. Patient and Table Preparation
Surgeon on anterior aspect of patient could be new for many surgeons.
Slight adjustment period as a result.
Discuss with participants that it is not an overwhelming adjustment.
(Add your own anecdotal experiences and learning curve before you were comfortable – i.e., how many cases.)
Patient and Table Preparation
Patient in direct lateral position
Securely held on table
Leg support modified to allow posterior leg positioning
Surgeon works on anterior side
Pelvic clamping system must be highly effective.
Rotational deforming forces on pelvis during femoral preparation tend to displace the pelvis.
Visualization of the femur can become markedly compromised.
“Bean bag” my be insufficient.
Some use peg board style system.

26. Draping Drape can become unstable Sterile bag
Something to be aware of.
Bag concept may be new to participants.
Draping
Drape can become unstable
Sterile bag
Operative leg must be placed in a sterile side pocket before elevating the limb for both trial and final reduction.
Helps prevent contamination during femoral preparation.

27. Team Positioning Surgeon Anterior 1st Assistant Distal/Posterior
Recommend two assistants for early cases especially.
Learning curve and skilled assistants may allow for one only.
First assistant is key as they will be manipulating leg position.
Assistants don’t need to see what’s occurring with AL procedure.
Educate assistants to avoid excessive retraction.
Assistant can work with you, or against you, especially with leg positioning.
Surgeon Anterior
1st Assistant Distal/Posterior
2nd Assistant Posterior

28. Skin Incision and Intermuscular Interval
We covered this briefly in an earlier slide.
Transition to following slide – refreshes learner’s memory on incision and interval.

29. Skin Incision
Discuss actual technique of identifying the interval and incision site.
Cover these aspects on the picture.
Tendency is to go distally with incision, which creates difficulty in locating interval and you end up going through the medius.
Extend incision over greater trochanter if desired – affords better exposure without disrupting underlying tissues.
Identify greater trochanter and anterior superior iliac crest
Extend incision from anterosuperior aspect of greater trochanter about 8cm to a point 2-4cm posterior to the ASIS
Leg is in position #1: neutral to slight hip abduction.
Recommend drawing the landmarks on the patients skin.
If the incision is too far superior and/or posterior, the acetabular view is impaired and may result in difficulty determining the muscle interval.
Anterior border of gluteus medius vulnerable to surgical damage, notably the forceful application of retractors.
Assistants need to be instructed on proper use of retractors and “mobile window”.
Leg is in neutral to slightly abducted position.

30. Approximate incision location
The Interval
1. Reinforces previous slides with a look at the deeper structures.
Tensor Fascia
Lata
Gluteus Medius
Approximate incision location

31. The Interval Gluteus Medius Head Greater Trochanter ASIS
Locate the anterior-superior of the greater trochanter.
There will commonly be a slight divergence of the gluteus medius and the tensor fascia lata in this region.
This is where you insert your finger/thumb to identify the intermuscular plane and separate the two muscles.
Note the leg position of neutral to slight abduction to relax the gluteus medius.
Tensor Fascia Lata
Gluteus Medius
Head
ASIS
Greater
Trochanter
Blunt finger dissection anterior to the greater trochanter is very effective in defining the glutei/tensor fascia lata interval superficially.
Should be able to sweep in interval with fingers down to capsule and over to greater trochanter.

32. Capsular Exposure The Instruments Retractors numbered for ease of use
Retractors are specifically designed to minimize soft tissue trauma and maximize exposure.
Remember that excessive retraction can lead to decreased visibility and potential tissue damage.
The Instruments
Retractors numbered for ease of use
Optimized radius to be gentle to muscle
Retractor 1
Retractor 2
Retractor 1 goes above the capsule and Retractor 2 goes below the capsule.
Will see this on the next slide.

33. The Interval Capsule Tensor Fascia Lata Gluteus Medius
Simple representation of the retractor positions.
Capsule
Tensor Fascia Lata
Gluteus Medius
Retractor 1 is inserted deep to the gluteus medius and minimus around the superior aspect of the femoral neck, superficial to the hip capsule.
Placement may be eased by directing the tip of the retractor superiorly underneath the medius and over the capsule.
The twist the handle 1800 into position with the retractor nip under the superior aspect of the femoral neck.
Retractor 2 is inserted deep to the tensor fascia lata, under the rectus femoris around the inferior border of the femoral neck, superficial to the hip capsule.
Retractors should always be levered on bone, not soft tissue.

34. Capsulotomy A “Z” shaped capsular incision with two flaps is created
Key is obviously ability to extend lateral capsular incision so that you can adequately expose the femur.
A “Z” shaped capsular incision with two flaps is created
Slight internal hip rotation
Neutral to slight hip abduction
Ability to extend lateral capsular incision can be critical to obtaining adequate femoral exposure
T or H shaped capsular incisions are certainly viable options
At anterior-superior portion, capsule may be obscured by overlying gluteus minimus or rectus femoris muscle.
Elevate muscle with a Cobb elevator.
Diagonal incision from lateral anterior-superior portion of greater trochanter medially to anterior inferior portion of the capsule.
Lateral portion of “Z” is along greater trochanter inferiorly.
Medial portion of “Z” is from medial anterior-inferior capsule in a superior direction.

35. This video shows the following actions/steps:
Palpate the greater trochanter and mark it.
Mark the incision line from the greater trochanter towards a point posterior to the ASIS.
Incision is made.
Note the leg is in slight abduction and neutral rotation.
Electrocautery down through the fascia to the muscle.
Interval between gluteus medius and tensor fascia lata is dissected with fingers.
Capsule can be palpated.
Retractors inserted.

36. Femoral Neck Exposure Retractors are replaced inside the capsule
Retractor 1 is placed inferiorly, under the femoral neck.
Retractor 3 is placed superiorly, under the femoral neck.
Clears the capsule and soft tissue from the field of view.
Retractors are replaced inside the capsule
Slight hip flexion can relax the gluteals and ease placement of Retractor 3.

37. Referencing The “Saddle” Other anatomical references
Referencing slide.
Double-checking pre-operative templating.
Ensures neck cuts will be accurate.
Speak to what you are using in particular as facilitator.
Key: saddle – dependable and repeatable landmark.
Use sawbones to illustrate.
Lesser trochanter accessed by placing leg in “figure-of-4” position.
The “Saddle”
Other anatomical references
Lesser trochanter can usually be palpated for cross reference
“Saddle”

38. First Neck Osteotomy Femoral head and neck are taken out in two pieces
Key: proximal neck cut needs to be into articular portion of the head - near the equator.
Inferior blade direction helps avoid cutting into the posterior acetabulum.
Note leg position.
Femoral head and neck are taken out in two pieces
First “neck” cut is in articular portion of femoral head
Direct blade inferior
Externally rotate maximally to approximately 60 or to allowable range of motion
Leg is externally rotated about 600 into position #2 with about 200 of abduction.
The higher the first osteotomy is made, the more easily the femoral head fragment will be removed – be cautious not to carry first cut too far medially as you can cut into the acetabulum.
Direct the saw blade inferiorly.

39. Neck-Head Disassociation
Leg position is transitioning during this step.
Key: be sure that proximal neck cut is complete before attempting to disassociate the head from the neck; otherwise, you risk longitudinal fracture of the neck.
Place Cobb elevator in the first neck cut
Move leg into extension and external rotation and lever with Cobb elevator to disassociate femoral neck from residual head and deliver neck into incision
Neck will now be parallel to the floor

40. Definitive Femoral Neck Cut(s)
Key: femur should be horizontal to the floor.
Move retractors distally from previous cut positions.
Note: osteotomy references.
Note: Make the vertical cut 1st – to avoid migrating into greater trochanter with angled cut.
Hip and leg are rotated 90 externally with thigh parallel to the floor
Slight hip flexion may help and saw must be adjusted accordingly
Retractors placed more distal on neck
Osteotomy - Identify references
Oblique portion based on preoperative plan for angle and position
Horizontal portion medial to trochanter
Leg position #3 – 900 of hip external rotation and knee flexed with femur parallel to the floor.
Retractor 1: tip inferior and medial to the proximal femoral neck.
Retractor 3: above and behind the superolateral femoral neck.
If necessary, position Retractor 4 lateral to Retractor 3 on the lateral aspect of the femoral neck.
Can be helpful in identifying the level of the second osteotomy.
Final cut based on pre-operative templating.

41. Femoral Head Removal
Reinforce equator cut with first osteotomy facilitates head removal.
Different methods to extract head (e.g., clamp, Steinmann pin, etc.).
External rotation of the femur moves it out of the field of vision for easier removal of head.
Proximal positioned first osteotomy facilitates easier removal
Leg position #4: neutral hip abduction/adduction with external rotation.
Slight hip flexion can help visualize and facilitate femoral head removal.
Can use Femoral Head Corkscrew or Steinmann pin – Femoral Head Stabilizer can also be used with the femoral head corkscrew.
Segmentation of the femoral head is possible if difficulty exists in removing it whole.

42. Initial neck cut near the equator of the femoral head.
Dissociation of the head from the neck with an osteotome.
Note the leg position with the hip in external rotation.
The definitive neck cut is made.
The neck piece is removed.
The remaining femoral head piece is then removed.
This video shows the following actions/steps:
Initial neck cut near the equator of the femoral head.
Dissociation of the head from the neck with an osteotome.
Note the leg position with the hip in external rotation.
Third retractor required at this stage.
The definitive neck cut is made.
The neck piece is removed.
The remaining femoral head piece is then removed.

43. Acetabular Exposure
The Instruments
Retractors
Retractor 1
Retractor 3

44. Acetabular Exposure Retractor Placement
Note placement of retractors on outside of acetabulum in anterior and posterior positions.
Retractor Placement
4 o’clock and 8 o’clock positions
Retractor 3
Leg is still in position #4: neutral abduction/adduction with external femoral rotation – slight hip flexion can help with visualization.
Retractors 1 and 3 are placed intra-capsularly around the acetabulum.
Position Retractor 3 directly posterior around the posterior wall of the acetabulum.
Position Retracor 1 around the anterior wall of the acetabulum.
“4-o’clock and 8 o’clock positions.”
If difficulty remains in exposure of acetabulum due to proximal femur, this usually means:
The neck is too long.
Insufficient capsule has been released around the medial greater trochanter.
Retractor 1

45. Acetabular Preparation
Show instruments to class.
Ask for questions.
Offset reamer handle is not required.
Do not exclusively rely on alignment frame for cup position – potential to over-antevert the cup with this procedure, especially for surgeons accustomed to posterior approaches.
The Instruments
Offset reamer handle, low profile reamers and offset cup positioner
Reamers are very aggressive – suggest starting in reverse once in acetabulum.
Insert reamer so that open part of reamer is directed surperiorly.

46. Acetabular Preparation
Reaming
Position handle superiorly with flat portion of low profile reamer resting on superior rim of acetabulum
Rotate reamer handle distally and position reamer
Hip flexion and abduction can facilitate insertion
Note the straight reamer handle – straight or offset can be used.
Offset recommended for obese patients to maintain alignment.
Leg still in external rotation.
Remove the labrum and overhanging soft tissue prior to acetabular reaming.
Remove any pulvinar remaining in the acetabular fossa.
Assistant must not forcefully oppose retractors – will limit visualization.
Use “mobile window” principles.
Release retraction on gluteus medius when surgeon not working in window to avoid damage to the muscle.
Recommended to start with reamer close to final estimated size seen in pre-operative templating.
Use retractors to protect soft tissue when inserting and removing reamers.

47. Acetabular Preparation
Again, don’t strictly rely on alignment frame due to potential over-anteversion.
There is a general tendency based on the view to underestimate anteversion.
Use pelvic sawbones model to demonstrate anteversion issues.
We’ll cover this in greater detail in the lab session.
Please ask if you have questions when performing the procedure.
Acetabular implant
Position acetabular shell in inserter so that the locking mechanism is easily visible superiorly after the shell has been inserted.
Make sure patient is aligned correctly on the table.
Gentle longitudinal traction placed on the leg can facilitate cup insertion.
May be necessary to slightly extend the incision to accommodate shell sizes greater than 62mm.
Avoid heavy retraction on the proximal femur – can posteriorly rotate the pelvis and result in an increase in anteversion of the shell.
Screws can be used in the cup
Be cautious with retractors as they can dislodge the cup when placing screws.

48. Acetabular reaming (note the use of straight-handled reamer).
Use of retractors to protect soft tissue when inserting and removing reamers.
Reaming creates good bleeding bone.
Additional soft tissue, labrum, and pulvinar are removed.
The cup is inserted.
The liner is inserted.
This video shows the following actions/steps:
Acetabular reaming (note the use of straight-handled reamer).
Use of retractors to protect soft tissue when inserting and removing reamers.
Reaming creates good bleeding bone.
Additional soft tissue, labrum, and pulvinar are removed.
The cup is inserted.
The liner is inserted.

49. Femoral Exposure - Leg Position
Moving on to femoral side.
Leg position changes significantly to extension, adduction, and external rotation.
Ability to achieve desired leg position will be dictated by capsule release (ties back to extending the lateral capsular incision).
First assistant can straddle leg to maintain position and hold retractors if necessary.
Foot and leg in a bag on the posterior table
Deliver the proximal femur into the incision for instrumentation
20 Extension
40 Adduction
90 External Rotation
This is leg position #5: 20 Extension, 40 Adduction, and 90 External Rotation
Leg is in a sterile side pocket/bag.
Essentially tibia is perpendicular to the ground.
If difficulty exists in elevating femur, more posterior-superior capsule may need to be released.
Retractor 3 around posterior medial corner of the osteotomized femoral neck.
Retractor 1 around posterior lateral aspect of the femur at the tip of the greater trochanter.

50. Femoral Preparation The Instruments: Angled/offset rasp handles
Demonstrate instruments and allow participants to examine.
Instruments may depend on system preference.
This is the key instrument in set – allows you to avoid proximal incision soft tissue damage and promotes correct rasp orientation.
Inadvisable to attempt procedure without this instrument.
The Instruments: Angled/offset rasp handles
400 Rasp Handle
300 Rasp Handle
CLS® Rasp Handle

51. Femoral Preparation Retractor placement
Cover retractor placement.
Cover personal experiences with assuring adequate exposure.
Note: anterior and lateral capsule remnants will impede complete visualization of femur.
Insufficient capsular release increases risk of greater trochanteric fracture related to excessive retraction.
Place dull bone hook in canal and lift to appreciate amount of femoral elevation then make capsular incision accordingly.
Retractor placement
Retractor 3 inferior and medial to cut femoral neck
Elevates femur
Retracts tensor & capsule
Retractor 1 lateral to posterior, superior tip of greater trochanter
Retracts abductors
Retractor 1
Retractor 3
Remove any residual anterior and lateral capsule at top of neck to deliver femur
Box osteotome or large burr to remove bone from medial portion of the greater trochanter.
Insert Charnley awl and advance it down the femoral canal equal to the length of the stem.
Broach/rasp incrementally.

52. 1. (need moderator notes).
This video shows the following actions/steps:
Demonstration of the leg position in external femoral rotation.
Use of an awl to start the canal.
Use of the box osteotome medial to the greater trochanter to prepare the canal for rasping/broaching.
Take as much out laterally to avoid putting implant in varus position.
Note the offset handles and how they facilitate insertion and soft tissue protection.
Note that the rasps/broaches are used incrementally.
Demonstration of the curved rasp/broach handle.
Note that the canal is easily viewed with proper leg positioning and elevation of the femur into the wound.

53. 1. (Need moderator notes).
This video shows the following actions/steps:
The final rasp/broach is applied.
The femoral component is inserted and impacted.
The head is placed and impacted.
Final reduction and motion testing – longitudinal traction helps with reduction.
Capsular and wound closure.

54. Wound closure Adapting capsule suture Deep drain 6 – 24 hours
Use preferred closure methods.
Add anecdotal information on your preferences.
Adapting capsule suture
Deep drain 6 – 24 hours
Closure of fascia
Subcutaneous suture
Intracutaneous suture
Consideration should be given to infiltration of the soft tissues around the wound with local anesthetic and other agents – avoid injection into the femoral triangle.

55. The Five Acts of Leg Positioning
1. Transition slide.
Surgical Recap:
The Five Acts of Leg Positioning

56. MIS Anterolateral Procedure
Procedure’s success is predicated on leg position.
These five acts of leg positioning represent the crucial aspects of the procedure.
We cannot overemphasize the importance of this concept.
Cover each and state you will go into detail on following slides.
We will review these in greater detail after you have been exposed to the individual steps of the surgical procedure.
The Five Leg Positions
Skin and Capsular Incisions/Closure
Transcapital Neck Cut
Definitive Neck Cut
Acetabulum
Femur

57. Leg Positioning Incisions Femoral Side Acetabular Side 1st Femoral Cut
Importance of leg position.
Assistant can work with you or against you.
Incisions
Femoral Side
Acetabular Side
1st Femoral Cut
Definitive Osteotomy

58. Skin and Capsular Incision
Mayo stand and arm elevator are utilized when only one assistant is available.
Create discussion as to what the associated steps of the procedure are related to this leg position.
Position 1
Assistant holds leg in neutral to slight hip abduction
Relaxes abductors to achieve maximum exposure
Mayo Stand
Arm Elevator

59. Transcapital Neck Cut Assistant holds leg in Foot in bag
Generate same discussion on associated steps of procedure.
Patients with severe arthritis will have restricted external rotation.
Assistant holds leg in
neutral ab/adduction
slight hip flexion
external rotation that anatomy allows
Foot in bag
Relaxes iliopsoas
Provides improved visualization of femoral neck
Position 2

60. Definitive Neck Cut Assistant moves leg into Foot in bag
Generate same discussion on associated steps of procedure.
Slight hip flexion may improve visualization here as it relaxes iliopsoas, HOWEVER, you will need to adjust saw angle accordingly.
Assistant moves leg into
90 External Rotation
Foot in bag
Femur parallel to floor
Tibia perpendicular to floor
Positions femoral neck parallel to floor to visualize cut
Position 3

61. Acetabulum Assistant moves leg into
Generate same discussion on associated steps of procedure.
Assistants do not need to visualize wound exposure.
Position 4
Assistant moves leg into
Full knee extension
Slight external hip rotation
Slight hip abduction and hip flexion can help insertion and extraction of reamers

62. Femur Assistant moves leg into Foot in bag
Generate same discussion on associated steps of procedure.
Position 5
Assistant moves leg into
90 External Rotation
20 Extension
40  Adduction
Foot in bag
Tibia perpendicular to floor
Elevates femur

63. Closure Assistant moves leg back to initial position
Review your methods of closure.
Assistant moves leg back to initial position

64. Transition slide.
Data included is based on experiences of Heinz Roettinger of Germany.
Roettinger previously utilized posterior approach.
Most early complications were related to implant selection and learning curve.
Now typically uses CLS® stem and Trilogy® cup (primaries only).
Also does revision THA with AL.
Further North American data is being collected and should be available shortly.
Clinical Data Associated With the Zimmer MIS Anterolateral THA Procedure

65. Clinical data 2 surgeons (03/03 – 2/05) >700 THA
Cover factually.
Ask for questions.
Add individual, anecdotal experiences as necessary.
2 surgeons (03/03 – 2/05)
>700 THA
Bodyweight 74.5 kg (min. 43 kg, max. 134 kg)
BMI 26 (maximum 42)
Surgery time 46 minutes
Retransfusion volume 302 ml (intraoperative to 6 hrs. postop.)
Röttinger, 2005

66. Clinical Experience – Early Results
Review of clinical experiences seen so far with MIS Anterolateral THA.
2 days Post-op
>700 patients
Excellent early mobilization
Decreased pain
Excellent abductor function
Excellent standard approach (also for revisions)
Acceptable learning curve
Röttinger, 2005

67. Clinical Experience—Complications
Most of these complications are part of the development of the approach and can be avoided with current instrumentation and techniques.
6 greater trochanteric fractures likely due to insufficient capsular release.
2 dislocations of acetabular component – potentially linked to learning curve and use of screws to stabilize cup early in learning process.
3 anterior dislocations ties back to point that potential exists to over-antevert the cup.
>700 patients
5 postop. periprothetic fractures
Caused by a particular femoral component
6 greater trochanter fractures
Asymptomatic
2 dislocations of the acetabular component
3 anterior dislocations
Increased anteversion of acetabular component (2 revisions)
Röttinger, 2005

68. Greater Trochanteric Fractures
Videos of patients who received the MIS Anterolateral THA procedure.
No dislocation
No muscle insufficiency
Likely related to insufficient lateral superior capsular release
Röttinger, 2005

69. Transition slide.
Discussion: Advantages, Disadvantages, and the Continuum of Care With the Zimmer MIS Anterolateral THA Procedure

70. Where does this new approach fit?
Highlight advantages of AL.
This is a summary/review of concepts already covered.
Great alternative for surgeons who prefer anterior approaches
Advantages
Theoretically better early abductor muscle function
Lateral femoral cutaneous nerve and lateral femoral circumflex vessel not in operative field
Acceptable surgical time
No intraoperative x-ray necessary
Acetabulum and femur directly visualized

71. Where does this new approach fit?
Highlight advantages of AL.
This is a summary/review of concepts already covered.
More Advantages
Familiar lateral positioning
Compatible with many Zimmer implants
Performed through small incision (patient preference)
Viable bail out

72. Where does this new approach fit?
Tie back to why to use minimally invasive procedures.
Reinforce key benefits.
For surgeons who prefer posterior approach
Many of the aforementioned features
with
New view of hip
Low dislocation rate
Time, experience and well designed studies will tell
Röttinger, 2005

73. Where does this new approach fit?
Highlight some potential challenges with this procedure.
Stress and reinforce the capsular release.
Potential Challenges
New surgeon positioning
May require two surgical assistants
Expect a variable learning curve
Initial risk of complications
Excessively anteverted cup
Insufficient capsular release
Varus stem
Greater trochanteric fracture
Obese and very muscular patients still difficult

74. Discussion Post-Op Care Anesthesia Challenges Patient Outcomes
Discuss your experiences and thoughts in these areas.
Post-Op Care
Anesthesia
Challenges
Leg Position
Interval
Capsular Incision
Acetabulum
Femur
Patient Outcomes

75. Conclusions This MIS anterolateral approach is intermuscular
Summary slide – captures the potential benefits of the procedure and the encouraging results to date.
This MIS anterolateral approach is intermuscular
Potentially little to no delay in rehab
Potentially little to no abductor weakness
Clinical results are encouraging

76. Ask for final questions.
Summarize any last key points.