Knee – Medial Approach

Modern Study Review (AI-Generated)

High-Yield Summary

The medial approach to the knee is a versatile, extensile exposure primarily indicated for medial compartment pathology, medial collateral ligament (MCL) injuries, and posteromedial corner reconstructions. It remains the gold standard for open procedures involving medial knee structures but is increasingly complemented by arthroscopic techniques for intra-articular pathology. This approach provides excellent visualization of the MCL, pes anserinus tendons, and posteromedial capsule while requiring meticulous protection of the saphenous nerve and vessels.

Applied Anatomy & Intervals

Internervous Interval

• No true internervous plane: Dissection proceeds through muscular and fascial planes with careful retraction.

Anatomic Landmarks

• Adductor tubercle (proximal landmark)
• Medial border of the patella (incision runs ~3 cm medial and parallel)
• Medial joint line (incision extends ~6 cm distal on anteromedial tibia)

Patient Positioning & Setup

• Table Type: Standard operating table with ability to flex the knee.
• Patient Position: Supine with the affected knee flexed to approximately 60°, hip flexed and externally rotated to optimize medial exposure.
• Specialized Equipment:
• Limb positioner or bolster to maintain knee flexion
• Tourniquet optional but often used for bloodless field
• C-arm positioned laterally if intraoperative imaging is required

Surgical Technique (The “Vital Steps”)

Incision & Superficial Dissection

• Make a long, curved incision starting 2 cm proximal to the adductor tubercle, curving anteriorly and inferiorly to a point 6 cm below the joint line on the anteromedial tibia.
• Incision runs parallel and approximately 3 cm medial to the medial border of the patella.
• Raise skin flaps carefully to expose the fascia.
• Identify and usually sacrifice the infrapatellar branch of the saphenous nerve, which crosses transversely.

Deep Dissection & Exposure

• Incise fascia along the anterior border of the sartorius muscle in line with its fibers, from tibial attachment to 5 cm above the joint line.
• Flex the knee to allow posterior retraction of the sartorius.
• Identify and retract the sartorius, gracilis, and semitendinosus muscles posteriorly to expose the superficial MCL insertion.
• For intra-articular access, incise the joint capsule anterior or posterior to the MCL depending on the target area.
• Posteromedially, separate the medial head of the gastrocnemius from the semimembranosus and posterior capsule to expose the posteromedial corner.

The “Danger Zone”

Post-Operative Pearl

Use a drain routinely to prevent hematoma formation under skin flaps, which can compromise skin viability. Early controlled mobilization is encouraged, but avoid valgus stress to protect MCL repair or reconstruction.

Classic Clinical Notes

Knee – Medial Approach

• Position:

Supine with affected knee flexed to 60° and hip flexed and externally rotated.

• Incision:
• Long, curved incision starting 2 cm proximal to adductor tubercle.
• Curves anteriorly and inferiorly to a point 6 cm below joint line on anteromedial tibia.
• Runs parallel to medial border of patella about 3 cm medial to it.

• Internervous Plane:

None.

• Dissection:
• Raise skin flaps to expose fascia.
• Infrapatellar branch of saphenous nerve crosses operative field transversely (usually cut).
• Saphenous nerve emerges between gracilis and sartorius.
• Long saphenous vein runs in posteromedial aspect of dissection.

Anterior to superficial MCL:

– Incise fascia along anterior border of sartorius in line with muscle fibers from tibial attachment to 5 cm above joint line.

– Flex knee to allow sartorius to retract posteriorly.

– Semitendinosus and gracilis exposed behind and beneath sartorius.

– Retract all three muscles posteriorly.

– Insertion of superficial MCL lies deep and distal to anterior edge of sartorius.

– Gentle traction to MCL exposes injury.

– For intra-articular exposure, incise joint capsule anterior to MCL.

Posterior to superficial MCL:

– Incise fascia along anterior border of sartorius.

– Retract three muscles of pes anserinus posteriorly.

– Separate medial head of gastrocnemius from semimembranosus.

– Separate medial head of gastrocnemius from posterior capsule.

– Exposes posteromedial corner.

– Incise capsule posterior to MCL for intra-articular exposure.

• Dangers:
• Infrapatellar branch of saphenous nerve (usually cut).
• Saphenous nerve (emerges between sartorius and gracilis with long saphenous vein).
• Long saphenous vein.
• Medial inferior genicular artery (curves around upper tibia; may be damaged when medial head of gastrocnemius lifted off posterior capsule).
• Popliteal artery (lies on posterior capsule in midline adjacent to medial head of gastrocnemius).

• Special Problems:
• Use drain — hematoma under skin flaps can cause skin necrosis.

Last Updated on January 25, 2026 by orthonet