Medial Parapatellar Approach

  • The medial parapatellar approach is a very useful approach to the knee joint. It allows excellent access to most structures when it’s extended to the full length of incision.

  • Portions of the incision can be used to gain access to the suprapatellar pouch, the patella, and the medial side of the joint.
  • The medial parapatellar approach can be used for:
    1. Total knee arthroplasty.
    2. Synovectomy.
    3. Open medial menisectomy.
    4. Open removal of loose bodies.
    5. Open ligamentous reconstructions.
    6. Patellectomy.
    7. Drainage of the knee joint in cases of sepsis
    8. Open reduction and internal fixation of distal femoral fractures with a medial plate.

  • Place the patient in a supine position on the operating table:
    • 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.

  • Landmark:
    1. Patellar ligament.
    2. Patella.
  • Incision:
    • 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.

  • There is no internervous plane in the medial parapatellar approach.
  • Intermuscular plane runs between:
    1. Rectus femoris muscle.
    2. Vastus medialis muscle.
      • Both are innervated by the femoral nerve.

  • Divide subcutaneous tissues below skin incision,
  • Deepen dissection between the vastus medialis muscle 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 total knee arthroplasty).
  • Retract or excise the infrapatellar fat pad.

  • Dislocate patella and flip it laterally:
    • Protect insertion of patellar tendon on tibia.
    • If difficult to flip patella then extend incision between rectus femoris and vastus medialis muscles proximally.
    • If contractures continue to prevent dislocation of the patella, then you can detach tibial tuberosity bone block and reattach afterwards with a screw.
  • Flex the knee to 90 degrees to gain exposure to entire knee joint.

  • Proximal Extension of medial parapatellar approach:
    • The approach can be extended proximally between the rectus femoris and vastus medialis muscles.
    • Split the underlying vastus intermedius muscle to expose the distal two thirds of the femur.
    • Stay in the distal third of the thigh; more proximally, the branches of the femoral nerve may become involved, resulting in partial denervation (Also see Anteromedial Approach to the Distal Two Thirds of the Femur).
  • Distal Extension medial parapatellar approach:
    • Mobilize the upper part of the attachment of the patellar ligament to the tibia or remove the patellar ligament with an underlying block of bone.
    • This extension may be useful in dealing with complex intraarticular fractures of the knee joint.
      (See the lateral approach to the distal femur).

  • The structures at risk during medial parapatellar approach include:
    1. Superior lateral genicular artery:
      • At risk during lateral retinacular release.
      • May be last remaining blood supply after medial parapatellar approach and fat pad excision.
    2. 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.
      • Its injury can lead to postoperative neuroma.
        • if cut during surgery, resect and bury end to decrease chance of painful neuroma
    3. 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.
          • Parallels longitudinal incisions are problematic so maximizing the skin bridge is important (5-6cm recommended clinically).

  • Surgical Exposures in Orthopaedics book - 4th Edition
  • Campbel's Operative Orthopaedics book 12th
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