Hip Arthroplasty Principles and Application

8/11/2019 Hip Arthroplasty Principles and Application

1/12

Hip ArthroscopyPrinciples andApplicationJ.W. Thomas Byrd, M.D.

Hip SeriesTechnique Guide


2/12

As described by:

J.W. Thomas Byrd, M.D.Southern Sports Medicine and Orthopaedic CenterNashville, TN

Introduction

Arthroscopic techniques have found wide applicabilitin both large and small joints of the body. In the hip,however, the application of these techniques brings light a number of unique considerations. The hip isencased in a dense soft tissue envelope that makesthe introduction of arthroscopic instrumentschallenging. Further, the constrained ball and socketbony architecture limits both access andmaneuverability of instrumentation within the joint.Finally, the strong, relatively non-compliant capsule isa factor in achieving adequate distraction of the jointDespite these challenges, arthroscopic surgery of thehip is becoming an increasingly well-recognizedclinical procedure. With well-founded basic principlesthe techniques of hip arthroscopy are evolving andthe indications continue to expand. Hip arthroscopy proving to be an invaluable tool in defining certainintraarticular lesions. Imaging techniques such as MR which are often important in discerningarthroscopically amenable lesions in joints such asthe shoulder and knee are currently less reliable ithe hip. Observations made during hip arthroscopy

can enhance our ability to more accurately interpretdiagnostic images and to correlate clinical findingswith pathology.


3/12

Hip Arthroscopy Principles andApplication

Patient Selection

Indications for hip arthroscopy include:

Loose bodies

Labral tears

Degenerative disease

Chondral injuries

Synovial disease

Joint sepsis

Avascular necrosis

S/P total hip arthroplasty

Ruptured ligamentum teres Unresolved hip pain

Removal of loose bodies represents the clearestindication for hip arthroscopy. The diagnosis is usuallyevident with currently available imaging techniquesincluding arthrography or arthro-CT scan. Oncediagnosed, the importance of loose body removal hasbeen well documented. Arthrotomy for debridementcarries greater associated morbidity than hiparthroscopy.

Labral tears are more elusive to diagnose than loosebodies. Neither MRI nor various arthrographytechniques are fully reliable in defining labral lesions.Were it not for the option of arthroscopic intervention,many of these patients would be resigned to l ivingwithin the constraints of their symptoms. However,with arthroscopy, a definite diagnosis can be madeand effective treatment instituted. Successfularthroscopic debridement of symptomatic labral tearscan produce very gratifying results.

Arthroscopic debridement has a limited role in themanagement of select patients with degenerativedisease. It is a palliative and temporizing procedurethat may potentially delay the subsequent need fortotal hip arthroplasty.

Similar to labral lesions, the diagnosis of isolatedchondral injuries may be elusive. However, whenrecognized, these injuries represent an excellentindication for arthroscopic management. Arthroscopyhas also found a role in select synovial disease andjoint sepsis.

Arthroscopic debridement in association withavascular necrosis of the femoral head has a verylimited place. Similarly, arthroscopy has occasionallybeen reported for removal of debris associated withtotal hip arthroplasty. Rupture of the ligamentum tereshas been discerned arthroscopically and arthroscopy

has also been reported for select cases of unresolvedhip pain.

Contraindications

Hip arthroscopy is contraindicated in the presence ofankylosis or advanced arthrofibrosis.

Soft tissue compromise, whether from disease,trauma or previous surgery, may contraindicate thepassage of instruments into the hip joint. Similarly,bony compromise, either of the joint architecture orpotential stress risers, regardless of the cause, may

contraindicate application of the distraction forcesnecessary for hip arthroscopy.

For hip arthroscopy, extra length instruments areusually necessary, even for moderate sized patients.Consequently, severe obesity may be a relativecontraindication to arthroscopic intervention.

Advanced disease states with destruction of the hipjoint also contraindicate arthroscopy as there can beno reasonable expectation of symptomaticimprovement.


4/12

4

Figure 2. Optimal vector for distraction is oblique relative to the axis ofthe body and more closely coincides with the axis of the femoral neckthan the femoral shaft. This oblique vector is partially created by hipabduction and partially accentuated by the small transverse componentachieved by lateralizing the peroneal post.

Operative Technique

Hip arthroscopy is performed as an outpatientprocedure, and usually under general anesthesia.Epidural anesthesia is an appropriate alternative butrequires an adequate motor block to ensure muscle

relaxation.

Patient Positioning

Hip arthroscopy can be performed with the patient ineither of the following positions:

Supine

Lateral Decubitus

For the first option, the patient is positioned supine oa modified fracture table. An oversized, formedurethane peroneal post is used and lateralized to theoperative side (Figure 1). Lateralizing the peroneal poadds a slight transverse component to the direction othe traction vector (Figure 2).

The operative hip is abducted approximately 25 andpositioned in extension. Although slight flexion mightrelax the capsule and facilitate distraction, it alsodraws the sciatic nerve closer to the joint making itmore vulnerable to injury. Thus, flexion of the hip joinduring arthroscopy is avoided.

It is important that the operative hip be in neutralrotation during portal placement. However, freedom o

rotation of the foot plate during arthroscopy should bassured to facilitate visualization of the femoral head

The non-operative hip is abducted as necessary toaccommodate placement of the draped C-armbetween the legs. The contralateral foot is anchoredwith slight traction in order to keep the pelvis fromshifting during distraction of the operative hip.

Traction is then applied to the operative extremity toconfirm the ability to distract the joint. Adequatedistraction typically requires 25 to 50 pounds of

traction. More force may be necessary for anexceptionally tight hip but should only be applied witsome caution. Distraction of the hip joint is confirmeby fluoroscopic examination.

If joint distraction is not readily achieved when initialtraction is applied, immediate application of furthertraction should be avoided. Rather, a delay of a fewminutes should be instituted to permit the capsule toaccommodate to the tensile forces. This often resultsin relaxation of the capsule and adequate distractionwithout the need for further traction.

Figure 1. Supine position for hip arthroscopy requires a peroneal post

lateralized to the operative side. The operative hip is placed inextension, approximately 25 abduction and neutral rotation.

Pressure

Peroneal Post

DistractionVector

Traction


5/12


6/12

6

4.5 mm, 5.0 mm and 5.5 mm extra length cannulasmay be used during hip arthroscopy. A 4.5 mmcannula allows interchangeability of the arthroscopeinstrumentation and the inflow. When the inflow isattached to the arthroscope bridge, a 5.0 mm cannuprovides the best flow hydrodynamics. A 5.5 mm

cannula is also available for extra length, largediameter shaver blades.

Special cannulated obturators can be advanced overa switching wire placed through the 17 gauge needleused in pre-positioning. Also, for freehand placemena custom sharp obturatorrather than a trocarallows for ease in penetrating the hip capsule withless risk of inadvertent articular damage (Figure 5).

Extra length curved shaver blades are useful foroperative arthroscopy around the convex surface

of the femoral head. Extra length flexible cannulasaccommodate passage of the curved blades (Figure 6

Hip arthroscopy also requires arthroscopic handinstruments specifically designed for use in the hipjoint. Importantly, although hand instrumentscommonly used in laparoscopic procedures may havthe required extra length, they are fragile and mayeasily break if used in the hip. Consequently,endoscopic hand instruments are contraindicated fouse during hip arthroscopy.

Figure 6. Extra length flexible cannula and extra length curved shaverblade facilitate operative arthroscopy around the femoral head.

Figure 5. Obturators and Trocar.

Standard Obturator

Sharp Trocar

Custom Sharp Obturator


7/12

Figure 7. Anatomical landmarks guide portal positioning.

Portal Location

Three standard portals are utilized for hip arthroscopy(Figure 7):

Anterior

Anterolateral

Posterolateral

The site of the anterior portal coincides with theintersection of a sagittal line drawn distally from theanterior superior iliac spine and a transverse lineacross the superior margin of the greater trochanter.The direction of this portal courses approximately 45cephalad and 30 towards the midline. Theanterolateral and posterolateral portals are positioneddirectly over the superior aspect of the trochanter atits anterior and posterior borders.

Anterior Portal*

The pathway of the anterior portal penetrates themuscle belly of the sartorius and the rectus femorisbefore entering the anterior capsule (Figure 8).Neurovascular structures of concern during portalplacement include the lateral femoral cutaneousnerve, the femoral nerve and the ascending branch ofthe lateral circumflex femoral artery.

At the level of the anterior portal, the lateral femoralcutaneous nerve typically divides into three or morebranches. Consequently, the portal usually passeswithin several millimeters of one of these branches.Because of the multiple branches, the nerve is noteasily avoided by altering the portal position. Rather, itis protected by utilizing meticulous technique in portalplacement. Specifically, the nerve is most vulnerableto a deeply placed skin incision which lacerates oneof the branches. Therefore, the initial stab woundshould be made carefully through the skin only.

Passing from the skin to the capsule, the anteriorportal runs almost tangential to the axis of the femoralnerve. The average minimum distance from the portal

to the nerve is 3.2 cm.

Although variable in its relationship, the ascendingbranch of the lateral circumflex femoral artery isusually approximately 3.7 cm inferior to the anteriorportal.

* Anatomic references are based on cadaver studies and areaverages only. Significant variances may exist. The surgeonmust be fully familiar with the anatomy and landmarks of theregion when performing hip arthroscopy.

Anterior Portal

Posterolateral Portal

Anterolateral Portal

Figure 8. Anterior Portal Pathway/Relationship to Lateral FemoralCutaneous Nerve, Femoral Nerve and Lateral Circumflex Femoral Artery

Femoral n.Lateral femoralcutaneous n.

Ascending branch,lateral circumflexfemoral a.

Rectusfemoris m.

Sartorius m.

Portal pathway


8/12

8

Figure 10. Posterolateral Portal Pathway/Relationship to Sciatic Nerveand Superior Gluteal Nerve

Anterolateral Portal*

The anterolateral portal penetrates the gluteus mediuprior to entering the lateral aspect of the capsule at ianterior margin (Figure 9).

The only structure of significance relative to theanterolateral portal pathway is the superior glutealnerve. After exiting the sciatic notch, the superiorgluteal nerve courses transversely, posterior toanterior, across the deep surface of the gluteusmedius. The average distance from the portal to thesuperior gluteal nerve is 4.4 cm.

Posterolateral Portal*

The posterolateral portal penetrates both the gluteusmedius and minimus prior to entering the lateralcapsule at its posterior margin. Its course is superior

and anterior to the piriformis tendon (Figure 10).

The posterolateral portal lies closest to the sciaticnerve at the level of the capsule with the distanceaveraging 2.9 cm. An average distance of 4.4 cmseparates the portal from the superior gluteal nerve.

Establishing Portals

The anterolateral portal lies most centrally in the safzone for arthroscopy. Thus, it is the first portalestablished for introduction of the arthroscope.Subsequent portals are then placed utilizing direct

arthroscopic visualization.

Pre-positioning is performed with a 6-inch, 17 gaugeneedle under fluoroscopic control. The hip joint isthen distended with approximately 40 cc of fluid andthe intra-capsular position of the needle confirmed bbackflow of fluid.

A stab wound is made through the skin at theentrance site of the needle. The switching wire isplaced through the needle. The needle is thenremoved, leaving the switching wire in place. The

cannulated obturator with the 5.0 mm arthroscopycannula is passed over the wire into the joint(Figure 11).

* Anatomic references are based on cadaver studies and areaverages only. Significant variances may exist. The surgeonmust be fully familiar with the anatomy and landmarks of theregion when performing hip arthroscopy.

Figure 9. Anterolateral Portal Pathway/Relationship to Superior Gluteal

Nerve

Sciatic n.

Piriformistendon

Gluteusminimus m.

Gluteusmedius m.

Piriformistendon

Portal pathway

Gluteusmedius m.

Superior gluteal n.

Portal pathway


9/12

Figure 11. The switching wire guides advancement of the 5.0 mmarthroscopy cannula/cannulated obturator assembly into the joint.

In establishing the portal, the cannula/obturatorassembly should pass close to the superior tip of thegreater trochanter and then directly above the convexsurface of the femoral head (Figure 12). It is importantto keep the assembly off the femoral head to avoidinadvertent articular surface scuff ing. However, it is

also important to stay below the lateral lip of theacetabulum. If the capsule is entered more cephaladin order to avoid the femoral head, the assemblycould penetrate and damage the labrum.

Once the anterolateral portal has been established,the arthroscope is inserted and initial orientation tothe joint is completed. It is best to use the 70arthroscope for placement of the other portals as itallows direct visualization of where the cannulaspenetrate the capsule.

The anterior portal is the second portal created. Pre-positioning is performed with the 17 gauge spinalneedle. Portal placement is facilitated by directvisualization through the arthroscope as well asfluoroscopy.

Finally, the posterolateral portal is placed. It isimportant to ensure that the hip has remained inneutral rotation. Specifically, if the hip is in externalrotation, the greater trochanterthe maintopographical landmark for portal placementmovesposteriorly. In turn, this change in trochanter locationmoves the portal pathway posteriorly, placing thesciatic nerve more at risk for injury (Figure 13).

As with anterolateral and anterior portal placement,pre-positioning is performed with the 17 gauge spinalneedle. Fluoroscopic control and direct arthroscopicvisualization are again used to ensure properplacement of the posterolateral portal.

Once all three portals have been established, one ofthe cannulas can be used for a separate inflow. The5.0 mm cannula can then be replaced with a 4.5 mmcannula allowing greater ease of interchangeability of

the arthroscope and instruments while assuringample flow from the third cannula.

Releasing the capsule around the portal sites with anarthroscopic knife passed through the cannula willalso improve the maneuverability of the arthroscopeand instruments within the joint.

Figure 12. Advancement of the assembly via the correct anterolateralportal pathway positions cannula directly above the convex surface ofthe femoral head.

Figure 13. Neutral rotation of the operative hip is essential forprotection of the sciatic nerve during placement of posterolateralportal.

GreaterTrochanter

PosterolateralPortal Pathway

Sciatic n.


10/12

Arthroscopic Examination

Systematic examination and operative arthroscopy othe hip are facilitated by interchanging theinstruments and arthroscope between the threeestablished portals (Figure 14). By utilizing both the

30 and 70 video-articulated arthroscopes, thestructures that can dependably be visualized includethe superior weight bearing portion of theacetabulum; the fossa; the ligamentum teres; and thanterior, posterior and lateral aspects of theacetabular labrum. Most of the weight bearingarticular portion of the femoral head can be visualizeintraoperatively by internally and externally rotatingthe hip.

The anterior wall and anterior labrum are bestvisualized through the anterolateral portal (Figure 15)The posterior wall and posterior labrum are best

visualized through the posterolateral portal (Figure 16The lateral labrum and its capsular reflection are besvisualized through the anterior portal (Figure 17). Thefossa and ligamentum teres can usually be visualizedfrom all three portals with a different perspective fromeach (Figure 18).

The inferior aspect of the acetabulum and femoralhead below the ligamentum teres, the inferior capsuand the transverse acetabular ligament areoccasionally able to be visualized.

At the completion of the procedure, traction isimmediately released. The portals are reapproximatewith nylon sutures and a sterile dressing is applied.

Postoperative Course

After hip arthroscopy, immediate ambulation isallowed. Protected weight bearing status is variabledepending on the pathology addressed andprocedure performed.

On the first postoperative day, the initial dressing isremoved and replaced with band-aids. Sutures are

removed between postoperative day three and fiveand replaced with steri-strips.

Figure 15. Anterolateral portal view.

Figure 14. Established portals allow instrument and arthroscope

interchange.

GreaterTrochanter

AnteriorWall

FemoralHead

AnteriorLabrum

Anterolateral Portal (Camera)

FemoralHead

Posterolateral Portal (Camera)

FemoralHead

Figure 16. Posterolateral portal view.

PosteriorWall

Femoral Head

PosteriorLabrum


11/12


12/12

2001, 2006 Smith & Nephew, All Rights Reserv

06/06 1030203 R

EndoscopySmith & Nephew, Inc.Andover, MA 01810

USA

www.smith-nephew.com978 749 1000978 749 1108 Fax

800 343 5717 U S C t S i

Additional Instruction

Prior to performing this technique,consult the Instructions for Useprovided with individualcomponents including

indications, contraindications,warnings, cautions, andinstructions.

Courtesy of Smith & Nephew, Inc.,Endoscopy Division

Caution: U.S. Federal law restricts thisdevice to sale by or on the order of a

physician.

Trademarks of Smith & Nephew. Certain marks

registered U.S. Patent & Trademark Office.

Documents

Hip Arthroplasty Principles and Application