Knee arthroscopy portals

Standard portals

• AL• AM• PM• SL

Superolateral portal

Anterolateral

• Created 1st blindly• Almost all structures clearly visualised except– PCL– Anterior portion of lateral meniscus– Periphery of posterior horn of medial meniscus

• 1cm above lateral joint line• 1cm lateral to patellar tendon• 1cm below patella

• The trochar and sleeve are inserted at 70° of knee flexion.

• Firm, gradual pressure applied until there is a reduction in resistance, indicating that the trochar has passed through the joint capsule.

• knee is extended to around 20° of flexion and the trochar advanced, passing through the patellofemoral joint

• Its intra-articular position can be confirmed by sweeping the arthroscope gently from side to side – it can be felt to be beneath the patella.

• If it is outside the knee joint, it will not sweep from side to side.

• position of the arthroscope should be confirmed before removing the trochar, introducing the camera and turning on the saline inflow

• Portal too near the joint line- – the ant. horn of the lateral meniscus can be lacerated– difficulty in maneuvering the scope.

• Too superior to the joint line- – prevents viewing of the posterior horns of the menisci

and other posterior structures. • Immediately adjacent to the edge of the patellar

tendon – can penetrate the fat pad, difficulty in viewing and in

maneuvering the scope within the joint.

Anteromedial

• For additional visualisation of lateral compartment and to probe lateral and medial compartment structures

• Location similar to AL• Needle inserted such that it exits just above

medial meniscus

Posteromedial

• 1cm above PM joint line in line with lateral border of medial femoral condyle

• ‘soft spot’ between the tendon of semimembranosus, the medial head of gastrocnemius and the medial collateral ligament.

• Before distention of the joint, this small triangle can be palpated easily with the knee flexed to 90 degrees.

• The knee must be maximally distended with irrigating solution so that the posteromedial compartment balloons out like a bubble when the knee is flexed to 90 degrees (saphnous nerve)

• For repair or removal of displaced posterior horn meniscal tears and for removal of posterior loose bodies that cannot be displaced into the medial compartment and removed through an anterior portal.

• For total synovaectomy

Superolateral portal

• most useful for viewing the dynamics of the patellofemoral articulation.

• lateral to the quadriceps tendon and about 2.5 cm superior to the SL corner of the patella.

• evaluation of patella tracking, patellar congruity, and lateral overhang of the patella and for suprapatellar synovectomy

Optional portals

• Posterolateral Portal• Proximal Midpatellar Medial and Lateral

Portals• Accessory Far Medial and Lateral Portals• Central Transpatellar Tendon (Gillquist) Portal

Posterolateral

• Knee flexed to 90 degrees and joint maximally distended.

• line drawn along the posterior margin of the femoral shaft intersects a line drawn along the posterior aspect of the fibula.

• 2 cm above the PL joint line at the posterior edge of the IT band and the anterior edge of the biceps femoris tendon.

• Soft point between the lateral head of gastrocnemius, LCL and the PL tibial plateau

• May damage the articular surface of the posterior femoral condyle

• plunging in with a sharp trocar into the popliteal space may damage neurovascular structures.

• The outflow of irrigation solution on removal of trocar confirms entry into the joint.

• This portal is useful for assisting with repair of lateral meniscal tears.

Proximal Midpatellar Medial and Lateral Portals

• view the anterior compartment structures, the lateral meniscocapsular structures, and the popliteus tunnel

• minimize accessory instrument crowding with the arthroscope during procedures requiring triangulation of several instruments into these compartments.

• Viewing posterior horns of the menisci and the tibial attachment of the PCL may be difficult

• located just off the medial and lateral edges of the midpatella at the broadest portion of the patella.

Accessory Far Medial and Lateral Portals

• used for triangulation of accessory instruments into the knee.

• approximately 2.5 cm medial or lateral to the standard AM and AL portals

• Medially, near the anterior edge of the tibial collateral ligament;

• laterally, anterior to the fibular collateral ligament and popliteus tendon.

• the meniscus or the collateral ligament can be lacerated, or the articular margin of the femoral condyle can be damaged.

Central Transpatellar Tendon (Gillquist) Portal

• 1 cm inferior to the lower pole of the patella in the midline of the joint through the patellar tendon.

• most helpful in ACL reconstruction procedures after graft harvest has been completed, avoiding tendon damage.

• If a transpatellar tendon portal is necessary for posterior compartment evaluation or anterior compartment triangulation, it is made with the knee in 90 degrees of flexion to keep the tendon under tension.