|
http://upload.orthobullets.com/topic/12028/images/1.jpg
http://upload.orthobullets.com/topic/12028/images/2.jpg
http://upload.orthobullets.com/topic/12028/images/3.jpg
http://upload.orthobullets.com/topic/12028/images/4.jpg
http://upload.orthobullets.com/topic/12028/images/5.jpg
http://upload.orthobullets.com/topic/12028/images/6.jpg
Introduction
  • Approach provides exposure to most structures of the anterior aspect of knee
  • Indications
    • total knee arthroplasty
    • synovectomy
    • open medial menisectomy
    • open removal of loose bodies 
    • open ligamentous reconstructions 
    • patellectomy
    • I&D of knee
    • ORIF of distal femoral fractures
      • with a medial plate
  • Contraindications
    • relative
      • previous utilization of a lateral parapatellar arthrotomy
  • Variations
    • midvastus approach (details below)
    • subvastus (Southern) (details below)
    
 
Preparation    
  • Anesthesia
    • general
    • spinal, epidural, and/or femoral blocks
  • Position
    • supine
      • with sandbag below buttock to internally rotate operative leg
      • with sandbag on end of table to support heel when knee is flexed to 90 degrees
  • Tourniquet
    • applied to thigh
 
Intermuscular Plane
  • Intermuscular plane
    • incise between rectus femoris (femoral nerve)  and
    •  vastus medialis (femoral nerve) 
 
Preparation & Position
  • Anesthesia
    • spinal, epidural, sciatic and/or femoral blocks
  • Position
    • supine
    • tape sandbag under hip to internally rotate leg
  • Tourniquet
 
Approach
  • Incision
    • landmark
      • palpate midline of patella in line to tibial tubercle
    • make midline longitudinal incision
      • begin 5 cm above superior pole of the patella
      • extending to the level of the tibial tubercle
      • curved or straight incision can be used
      • and can be done with knee flexed
  • Superficial Dissection
    • divide subcutaneous tissues below skin incision
    • deepen dissection between the vastus medialis and quadriceps tendon
    • develop medial skin flap to expose the  quadriceps tendon, medial border of the patella, and medial border of the patellar tendon
    • perform medial parapatellar arthrotomy 
      • take care not to damage the anterior insertion of the medial meniscus (irrelevant for TKA)
    • retract or excise the infrapatellar fat pad
  • Deep dissection
    • dislocate patella and flip laterally
      • protect insertion of patellar tendon on tibia
      • if difficult to flip patella then extend incision between rectus femoris and vastus medialis proximally
      • if contractures continue to prevent dislocation of the patella then can detach tibial tuberosity bone block and reattach afterwards with a screw
    • flex knee to 90 degrees to gain exposure to entire knee joint
  • Extension
    • proximal
      • may extend to distal two thirds of femur
      • incise between rectus femoris and vastus medialis
      • split underlying vastus intermedius to expose femur
  • Variations
    • midvastus approach
      • proximal portion of the arthrotomy extends into the muscle belly of the vastus medialis 
      • patella can be difficult to evert and is subluxated laterally instead
    • subvastus (Southern) parapatellar approach 
      • muscle belly of the vastus medialis is lifted off the intermuscular septum
      • patella can be difficult to evert and is subluxated laterally instead
      • benefits include
        • preserving the blood supply to the patella
        • preserving the anatomy of the quadriceps tendon (maintains stability of knee)
 

 
Clinical Images
  
Dangers
  • Superior lateral genicular artery
    • at risk during lateral retinacular release
    • may be last remaining blood supply after medial parapatellar approach and fat pad excision
  • Infrapatellar branch of saphenous nerves
    • saphenous nerve becomes subcutaneous on medial aspect of knee after piercing the fascia between the sartorius and gracilis
    • saphenous nerve then gives of infrapatellar branch that provides sensory to the anteromedial aspect of the knee
    • injury can lead to postoperative neuroma
      • if cut during surgery, resect and bury end to decrease chance of painful neurom
  • Skin Necrosis  
    • cutaneous blood supply may be tenuous in cases of previous surgery (revision TKA) or poor host (rheumatoid etc.)
      • skin is supplied by perforating arteries which run in the muscular fascia so any medial or lateral skin flaps (if needed) should be just below (deep to) the fascia to avoid skin necrosis
      • old incisions should, as best as possible, be crossed at 90 degrees.
        • parellel longitudinal incisions are problematic so maximizing the skin bridge is important (5-6cm recommended clinically)
 

Please rate topic.

Average 3.8 of 12 Ratings

Questions (2)
EVIDENCE & REFERENCES (3)
VIDEOS (1)
Topic COMMENTS (0)
Private Note