The Hip - book
Home » Joints » Hip » Anterolateral Approach to Hip Joint: (Watson Jones)

Anterolateral Approach to Hip Joint: (Watson Jones)

(see also: Smith Peterson Approach)

Discussion

  • major problems with the Watson Jones technique are dealing w/ gluteus medius & minimus, which lie over anteior capsule and must be damaged or cut to obtain adequate exposure;
    • original Charnely technique used anterolateral approach w/ pt supine, osteotomy of greater troch, & ant dislocation of hip;
    • this approach is used less commonly now as result of problems related to reattachement of the greater trochanter;
    • other major problem is dealing w/ medius & minimus, which lie over anterior capsule & are damaged or cut to obtain adequate exposure;

Incision

  • skin incision is made 2.5 cm behind ASIS to tip of greater trochanter;
  • then extend incision vertically down along anterior margin of trochanter for about 10cm;
  • or carry incision it to a point just posterior to trochanter, & then angle it about 110 deg anteriorly and distally to parallel the femoral shaft;

Interneural Interval

  • interval between tensor fascia lata & gluteus medius is identified;
    • overlying gluteal fascia is divided allowing these muscles to be separated up to iliac crest;
    • upper ends of these 2 muscles may be fused;
  • dissection of interval may facilitated more easily by beginning separation between ASIS & greater trochanter, before tensor fasica lata ends w/ its fascial insertion;
  • carry dissection proximally to expose branch of superior gluteal nerve, which innervates TFL;

Alternative

  • or make similar incision in underlying iliotibial band & retract tensor fascia lata medially & gluteus medius laterally;
  • then incise transversely gluteus medius attachment to greater troch until bursa between gluteus mimimus & troch is opened;

Deep Dissection

  • anterior parts of gluteus medius & minimus are raised from hip bone & retracted posteriorly;
  • upper part of Capsule of hip joint will been seen, w/ reflected head of rectus femoris attached to upper part of acetabular rim;
    • this head can be detached to give greater exposure of capsule, which may if indicated, may be incised or removed;
  • ascending branch of lateral femoral circumflex art. & its accompanying veins cross gap deep to these muscles and must be ligated;

 Osteotomy

  • osteotomy of greater troch is performed only if necessary to obtain exposure or to correct posterior displacement of trochanter;

Capsule

  • - make a longitudinal incision in the joint Capsule
  • make a transverse incision in the anterior margin of the acetabulum.
  • exteranally rotate the limb;
  • femoral head is exposed for osteotomy and removal from acetabulum;
  • if the posterior wall of the neck is longer than the anterior neck, there will be increased anteversion;
  • perform a complete capsulectomy - especially w/ an external rotational deformity;
  • pull anteriorly piriformis tendon and the attachments of the other short external rotators and divide them;
  • femoral nerve & vessels are anteroinferior to acetabulum and must be carefully protected.
  • carefully section quadratus femoris muscle until the perivascular fat surrounding the circumflex anastomosis is identified;

Hazards

  • ascending branch of LFCA and accompanying veins are large vessels that pass deep to rectus femoris,  tensor fascia lata, and gluteus medius, & require ligation as the gap between the tensor and gluteus medius is opened up;
  • nerve to tensor fascia lata also crosses gap (at higher level than vessels) and should be preserved, but it can be sacrificed if necessary for adequate exposure;
  • sciatic nerve must not be damaged if joint is being dislocated to remove the head for a prosthetic replacement; consider detaching & spliting only anterior third of gluteus medius to limit risk of damage to superior gluteal nerve, which passes 4.5 cm above and 2 cm behind the tip of greater trochanter

References