Medial Femoral Condyle

For Medical Students

Structure and Location

The medial condyle is the longer of the two in the sagittal plane and extends further distally. Held at the end of a femur, it is the condyle that reaches the table first.

Its articular surface is more curved than the lateral and narrower from side to side, and the cartilage over it is of the order of 2 to 3 mm thick. The surface continues round onto the posterior aspect, and the most posterior part only articulates at deep flexion.

On the outer wall are the medial epicondyle and, above it, the adductor tubercle. The lateral surface of the condyle forms the medial wall of the intercondylar notch.

Relations

Medially, outside the capsule: the superficial medial collateral ligament from the epicondyle, adductor magnus inserting on the adductor tubercle, the medial patellofemoral ligament in the region between the two, and the medial head of gastrocnemius arising above and behind.

Inside the notch: the posterior cruciate ligament attaches to the lateral surface of this condyle.

Posteriorly the medial head of gastrocnemius separates the condyle from the popliteal contents, and the semimembranosus passes distally to the posteromedial tibia.

Function

The medial condyle carries the greater share of load through most of the range, conventionally taught as about 60 per cent in a normally aligned knee in stance. That follows from its position relative to the mechanical axis rather than from anything about its shape.

Because it is longer front to back, the medial side of the joint translates less through flexion than the lateral. The medial condyle acts more as a pivot and the lateral as the side that travels.

Clinical Relevance

The adductor tubercle and the medial epicondyle are the two landmarks used to find the medial patellofemoral ligament and the superficial collateral through skin.

The medial condyle is the commonest site of osteochondral problems on the femoral side, and its load bearing position is the reason. The conditions themselves belong to Section 6.

MRCS Level

Structure and Location

Three features are worth naming. The articular surface is convex in both planes and more sharply curved in the sagittal plane than the lateral condyle. The outer wall carries the epicondyle and the adductor tubercle, with a shallow depression between them. The inner wall is flat and forms the notch.

The relationship of the three medial attachments to each other is a standard question. The adductor magnus inserts highest, on the tubercle. The superficial collateral arises lowest, from the epicondyle. The medial patellofemoral ligament arises between them, in the depression, closer to the tubercle than to the epicondyle.

The posterior part of the surface carries a flattened area against which the posterior horn of the medial meniscus lies at deep flexion.

Relations

Capsular: the capsule attaches close to the articular margin anteriorly and medially, and further from it posteriorly, so the posterior condyle has an intracapsular portion.

Medial layered anatomy: superficial to the condyle lie, in order, the deep fascia with the sartorius, then the superficial medial collateral ligament, then the capsule with its deep collateral fibres attaching to the meniscus. That layering is the subject of 2.9.1.

Posteromedially, the medial head of gastrocnemius arises from the condyle above the joint line, and the semimembranosus and the posterior oblique fibres reinforce the corner.

The saphenous nerve and its infrapatellar branch cross the medial side distal to the condyle and are relations of the approach rather than of the bone.

Blood Supply and Innervation

Supply is from the superior medial and inferior medial genicular arteries, reaching the epiphysis through the capsular and retinacular attachments, with the descending genicular artery contributing above.

The notch surface and the posterior cruciate attachment are supplied by the middle genicular artery.

Articular innervation is from the obturator nerve medially, with contributions from the femoral nerve through the nerve to vastus medialis and from the tibial nerve posteriorly.

Function

The medial compartment behaves as the more constrained of the two: a more curved femoral surface on a concave tibial surface, with the meniscus less mobile than its lateral counterpart.

That constraint is why medial translation through flexion is small and why rotation of the tibia occurs about an axis closer to the medial side than to the centre of the joint. 3.13 develops this.

Clinical Relevance

The medial epicondyle and adductor tubercle are the landmarks for medial patellofemoral ligament reconstruction, and the ligament's femoral attachment lying between them rather than on either is the reason placement is checked rather than assumed.

Gastrocnemius arising from the condyle above the joint line means a posteromedial exposure can be developed by taking the muscle off the bone without entering the joint.

The medial condyle is where femoral osteochondral lesions and spontaneous osteonecrosis most often appear. The anatomy explains the site; Section 6 owns the disease.

FRCS Level

Relations

The posteromedial corner is a layered structure and the condyle is its anchor. Working there means knowing which layer carries which restraint, because the layers separate cleanly in a cadaver and far less cleanly in a swollen knee.

The gastrocnemius origin is the structure that protects the popliteal contents during a posteromedial exposure, and the plane anterior to it is the one that stays safe.

Function

The medial compartment carries more load and accommodates less motion, which is why it tolerates malalignment poorly and why varus loads it further.

Restoring medial geometry matters more than restoring lateral geometry for the same reason. The lateral side can absorb a difference in translation; the medial side cannot, because it was not translating in the first place.

Clinical Relevance

Medial condylar geometry is the reference for the medial resection in arthroplasty, and for the correction in a distal femoral osteotomy. Both are technical decisions owned elsewhere, and both are made against this surface.

In cartilage work on the medial condyle, the load bearing zone is the part in contact near extension rather than the geometric centre of the surface. That distinction decides whether a lesion is weight bearing.

The femoral attachment of the medial patellofemoral ligament lies close to the physis in a skeletally immature knee, which constrains reconstruction in that group. Section 10 owns the paediatric decision.