Supine | Vastus Medialis / Adductor Plane | Femoral Vessels at Risk
- Internervous plane between vastus medialis (femoral nerve) and the adductor group (obturator nerve)
- The superficial femoral artery, femoral vein and saphenous nerve lie in the adductor (subsartorial/Hunter's) canal - the key danger
- Perforating branches of the profunda femoris cross to the linea aspera and must be ligated during subperiosteal stripping
- Uncommon approach - the lateral approach is the standard exposure for the femoral shaft
- Indications are vascular access or repair, medial bone grafting, selected nonunions and tumours
When & Why
Why the medial approach and when it is used. The medial approach to the femur is an uncommon surgical exposure. For the vast majority of femoral shaft problems the lateral approach is standard, because it avoids the major neurovascular structures of the medial thigh and gives extensile access to the whole shaft through a single internervous/intermuscular plane. The medial approach is therefore reserved for specific situations in which the surgeon needs direct access to the medial femoral cortex, to the superficial femoral vessels, or to a lesion on the medial aspect of the bone that cannot be reached safely from the lateral side. Primary indications
Exposure of the superficial femoral artery through the adductor canal - for arterial repair, bypass, embolectomy or arteriovenous fistula work. Performed jointly with a vascular surgeon; this is the commonest modern indication for the approach.
Delivery of cancellous autograft to the medial cortex for a femoral shaft nonunion, particularly the hypertrophic or atrophic nonunion that needs biological enhancement on its compression (medial) side.
Direct access to a medial nonunion site for debridement, opening of the medullary canal and fixation when the lateral side has already been addressed or is unsuitable.
Biopsy or resection of a lesion on the medial or distal femur (for example a distal femoral resection for a giant cell tumour) where a medial corridor gives the required clearance.
Buttress plating of a comminuted distal femoral fracture with a medial column fragment that cannot be captured from a lateral approach, as part of a double-plating construct.
Drainage and debridement of medial thigh or femoral infection, including medial sequestra, where the lateral route would not reach the focus.
Position and landmarks. The patient is supine with the affected limb draped free. The hip is flexed, abducted and externally rotated (a frog-limb position) to bring the medial thigh uppermost, and the knee is flexed to relax the posterior structures; a bump under the ipsilateral buttock helps roll the limb into external rotation. For the proximal third (femoral triangle) more flexion and abduction is used; for the distal third the knee is flexed over a bolster with the foot on the table. The surface landmarks are the adductor tubercle (distal) and the pubic tubercle (proximal); the incision runs longitudinally along the line between them, centred on the pathology and following the oblique course of sartorius.
| Landmark | Location | Why it matters |
|---|---|---|
| Adductor tubercle | Medial distal femur, just below the medial epicondyle | Distal end of the incision line |
| Medial femoral condyle | Medial aspect of the knee | Confirm distal extent and joint level |
| Pubic tubercle | Anterior groin | Proximal landmark for the femoral triangle |
| Adductor longus tendon | Groin, medial border of the femoral triangle | Apex of the femoral triangle = start of the adductor canal |
| Patella | Anterior knee | Reference for rotation and joint line |
Contraindications and alternatives. Most femoral shaft fractures are better served by the standard lateral approach, antegrade or retrograde intramedullary nailing, or minimally-invasive plating. Active skin infection or a compromised medial soft-tissue envelope, and a lack of vascular surgical support when the indication is vascular, argue against the approach. When only the lateral or anterior cortex is needed, the lateral or anterolateral approach is safer and more extensile.
| Approach | Plane | Best for | Main risk |
|---|---|---|---|
| Lateral | Vastus lateralis / lateral intermuscular septum | Standard for shaft fracture fixation | Perforators of profunda at the linea aspera |
| Anterolateral | Between vastus lateralis and rectus femoris | Proximal and mid-shaft; vascular access to profunda | Femoral nerve branches |
| Posterolateral | Behind the lateral intermuscular septum | Posterior cortex exposure | Sciatic nerve (proximal), perforators |
| Posterior (Henry) | Between hamstrings | Posterior surface of shaft | Sciatic nerve, profunda perforators |
The Exposure
The medial approach exploits the internervous plane between the vastus medialis (femoral nerve) and the adductor group (obturator nerve). The same interval houses the adductor (subsartorial) canal, which is why the superficial femoral vessels and the saphenous nerve dominate the list of structures at risk. Work down through the layers along the line from adductor tubercle to pubic tubercle, identify and protect the canal contents, then strip vastus medialis subperiosteally off the medial cortex.
| Muscle | Position | Nerve supply |
|---|---|---|
| Vastus medialis | Retracted anteriorly | Femoral nerve |
| Adductor longus (proximal) | Retracted posteriorly | Obturator nerve |
| Adductor magnus (distal) | Retracted posteriorly | Obturator nerve (with a tibial component to magnus) |
The adductor (subsartorial, Hunter's) canal runs from the apex of the femoral triangle (where sartorius crosses adductor longus) to the adductor hiatus in the tendon of adductor magnus, about one hand's breadth (approximately 7 to 10 cm) proximal to the knee. It is roughly 15 cm long. Its walls are sartorius and its fascia (roof/anteromedial), vastus medialis (lateral wall) and adductor longus then adductor magnus (posterior wall/floor). It carries the superficial femoral artery, the femoral vein, the saphenous nerve and the nerve to vastus medialis. At the hiatus the superficial femoral artery becomes the popliteal artery.
Cross-sectional and surface diagram of the medial approach to the femoral shaft: the longitudinal incision along the adductor tubercle-to-pubic-tubercle line, the sartorius reflected to reveal the adductor canal, and the internervous plane between vastus medialis (retracted anteriorly) and the adductor group, with vessel loops protecting the superficial femoral artery, femoral vein and saphenous nerve.
Context: A verified image is being sourced for this exposure.
Exposure sequence
- Make a longitudinal incision over the line from adductor tubercle to pubic tubercle, centred on the pathology and long enough to expose what is required.
- Incise subcutaneous tissue; identify and preserve or ligate crossing branches of the long saphenous vein (the vein itself runs subcutaneously on the medial thigh and may be met distally).
- Incise the deep fascia (fascia lata) longitudinally in the line of the incision.
- The sartorius is the key superficial landmark, crossing the thigh obliquely from anterior-superior to posterior-inferior.
- Free its deep surface and retract it as needed; the subsartorial canal lies directly deep to sartorius.
- Develop the plane between vastus medialis (anteriorly/laterally) and the adductor group (posteriorly/medially).
- Retract vastus medialis anteriorly and the adductors posteriorly - the true femoral/obturator internervous plane.
- As the plane opens, the contents of the adductor canal come into view - the superficial femoral artery and vein and the saphenous nerve.
- Identify them, protect them with vessel loops, and mobilise them anteriorly with vastus medialis or posteriorly with the adductors, depending on the target.
- Never place a metal retractor directly on a vessel - use gentle vessel loops and release retraction periodically.
- Once the vessels are controlled, incise the periosteum / medial intermuscular septum longitudinally.
- Strip vastus medialis off the medial femoral cortex subperiosteally to expose bone; remain strictly on bone.
- As stripping approaches the linea aspera, the perforating branches of the profunda femoris (usually four) are met passing from deep to superficial through the adductor mass.
- Coagulate or ligate each one carefully to prevent brisk, deep bleeding that retracts behind the adductors.
- With the medial cortex exposed and the canal contents protected, perform the indicated procedure - vascular repair, bone grafting, fixation, debridement, or tumour resection.
- The medial cortex and the superficial femoral vessels are now both under direct control.
The defining risk of this exposure is injury to the superficial femoral artery or vein and the saphenous nerve within the adductor canal. Identify the canal contents early, protect them with vessel loops, and never clamp a self-retaining or metal retractor directly onto a vessel. If a major vessel is injured, obtain proximal and distal control, call vascular surgery, and repair primarily or with an interposition graft. The profunda perforators at the linea aspera must be caught and ligated as they are divided, or they retract behind the adductors and bleed briskly.
All bone work stays strictly subperiosteal on the medial cortex. This keeps you off the profunda perforators that hug the linea aspera, and keeps the canal contents protected on the muscle side of the dissection. Identify the canal contents first, then go to bone.
Dangers & Extensions
Structures at risk, layer by layer
| Layer | Structure | Type | Protection |
|---|---|---|---|
| Subcutaneous | Long saphenous vein branches | Vein | Preserve; ligate small crossing branches |
| Subcutaneous | Saphenous nerve | Sensory nerve | Protected in the canal; exits distally to the medial knee |
| Canal | Superficial femoral artery | Artery | Identify, vessel loop, mobilise |
| Canal | Femoral vein | Vein | Mobilise with the artery; avoid direct retraction |
| Canal | Nerve to vastus medialis | Motor nerve | Protect so vastus medialis is not denervated |
| Muscle plane | Obturator nerve branches | Motor nerve to adductors | Retract the adductors as a group; stay in the plane |
| On bone | Perforators of profunda femoris | Arteries | Stay subperiosteal; coagulate or ligate at the linea aspera |
Consequences of injury - Saphenous nerve - sensory loss over the medial leg and foot; no motor deficit, but a source of numbness and neuroma pain.
- Superficial femoral artery or vein - serious bleeding and leg ischaemia if arterial; requires immediate repair by a vascular surgeon.
- Nerve to vastus medialis - weakness of knee extension (terminal extension) and a risk of patellar instability.
- Obturator nerve - weakness of hip adduction.
- Profunda perforators - brisk deep bleeding that retracts behind the adductors and is hard to control if not caught as it is divided. How to extend the approach. Extend proximally toward the groin, following the adductor longus tendon to its origin, to open the femoral triangle and expose the common and superficial femoral vessels and the origin of the profunda femoris - useful for proximal vascular exposure. Extend distally, medial to the knee and curving toward the popliteal fossa, following the superficial femoral artery through the adductor hiatus where it becomes the popliteal artery; this connects with the medial approach to the knee for distal vascular access and popliteal repair. Closure. Achieve meticulous haemostasis, paying particular attention to the perforator stumps at the linea aspera. Reapproximate the plane between vastus medialis and the adductors where possible, but this interval often cannot be closed tightly and should not be forced. Close the deep fascia (fascia lata) with absorbable suture if it was incised, place a suction drain for significant dead space or expected ooze, and close subcutaneous tissue and skin in layers. Document the distal pulses and the saphenous nerve territory before and after the procedure. Immediate post-operative care - Neurovascular monitoring: document distal pulses (dorsalis pedis and posterior tibial), capillary refill, and the saphenous nerve sensory territory, compared with the pre-operative baseline.
- Elevate the limb to reduce swelling.
- Watch for compartment syndrome: increasing pain despite analgesia, pain on passive stretch, and a tense swollen thigh are red flags.
- DVT prophylaxis per institutional protocol (mechanical plus chemoprophylaxis as appropriate), particularly after vascular or tumour work. Complications
| Complication | Prevention | Management |
|---|---|---|
| Superficial femoral artery injury | Identify early; vessel loop; stay subperiosteal | Direct vascular repair with vascular surgery |
| Brisk bleeding from profunda perforators | Ligate as encountered at the linea aspera | Direct pressure; identify and ligate the stump |
| Saphenous nerve injury (numbness) | Protect in the canal; gentle retraction | Usually observation; neuroma excision if painful |
| Nerve to vastus medialis injury | Identify with the artery; avoid over-retraction | Observe; physiotherapy for extension weakness |
| Haematoma | Meticulous haemostasis; drain for dead space | Evacuation if tense or infected |
| Infection | Aseptic technique; prophylactic antibiotics | Debridement and antibiotics; remove hardware if loose |
Outcomes. Outcomes are governed by the underlying indication rather than the approach itself. Vascular repairs depend on the injury pattern and time to revascularisation. Medial bone grafting for nonunion succeeds when the mechanical environment is stable and the biological stimulus is adequate. Tumour resection outcomes follow oncological principles and margins. Because the approach is uncommon and the indications heterogeneous, there is no single outcome metric - the principles of safe exposure, vascular protection, and meticulous closure are what the examiner is testing.
Procedures Through This Approach
The medial approach is tailored to the proximal, middle or distal third of the femur and can be extended proximally into the femoral triangle and distally toward the popliteal fossa, which is what makes the same corridor useful across such different indications.
| Zone | Procedure | Key consideration |
|---|---|---|
| Proximal third | Femoral triangle vascular access | Profunda origin and common femoral vessels |
| Middle third | Medial bone grafting for nonunion | Protect the canal contents; expose the medial cortex |
| Middle third | Tumour biopsy or resection | Plan the margin with imaging beforehand |
| Distal third | SFA / popliteal vascular repair | Joint vascular-surgical consent and support |
| Distal third | Medial-column buttress plating | Often part of a double-plate distal femur construct |
Viva & Exam Focus
MEDFEMMEDFEM - the medial femur approach in six safe steps
NAVSNAVS - contents of the adductor canal
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“Describe the medial approach to the femoral shaft, including the internervous plane and the structures at risk.”
“A patient needs exposure of the superficial femoral artery in the adductor canal for vascular repair. How would you plan and perform the medial approach, and how would you extend it for full control?”
“A patient has an established femoral shaft nonunion and you plan posteromedial bone grafting. Describe how you would use the medial approach and how you avoid its dangers.”
Position & Landmarks
- Supine with the hip flexed, abducted and externally rotated
- Knee flexed; bump under the ipsilateral buttock aids external rotation
- Landmarks: adductor tubercle (distal) and pubic tubercle (proximal)
- Longitudinal incision along the line between them, centred on the pathology
- Sartorius crosses obliquely and is the key superficial landmark
Internervous Plane
- Vastus medialis (femoral nerve) retracted anteriorly
- Adductor group (obturator nerve) retracted posteriorly
- A true femoral/obturator internervous plane
- Sartorius (femoral nerve) is superficial and retracted
- The adductor canal lies within this interval
Adductor Canal (Hunter's)
- Roughly 15 cm long, apex of femoral triangle to adductor hiatus
- Adductor hiatus about one hand's breadth proximal to the knee
- Walls: sartorius roof, vastus medialis lateral, adductor longus then magnus posterior
- Contents: superficial femoral artery, femoral vein, saphenous nerve, nerve to vastus medialis
- SFA becomes the popliteal artery at the adductor hiatus
Structures at Risk
- Superficial femoral artery and vein in the canal - the key danger
- Saphenous nerve (sensory, longest branch of femoral nerve)
- Nerve to vastus medialis (largest branch of femoral nerve)
- Obturator nerve branches to the adductors
- Perforating branches of the profunda femoris at the linea aspera
Indications & Procedures
- Uncommon - lateral approach is standard for the shaft
- Vascular access and repair of the superficial femoral artery
- Medial and posteromedial bone grafting for nonunion
- Selected tumour biopsy or resection of the medial/distal femur
- Medial-column buttress plating of comminuted distal femur fractures
Extension & Closure
- Proximal: toward the groin, opening the femoral triangle and profunda origin
- Distal: toward the medial knee and popliteal fossa via the adductor hiatus
- Meticulous haemostasis, especially the perforator stumps
- Reapproximate the plane loosely; do not force it closed
- Suction drain for dead space; document distal pulses
References
Guidelines, Registries & Global Practice The medial approach to the femur is a surgical exposure rather than a disease entity, so there are no treatment registries attached to it. Practice converges worldwide on a few principles common to advanced orthopaedic practice, DNB/MS, MRCS and SICOT curricula: the lateral approach is the global standard for femoral shaft fixation and the medial approach is reserved for specific indications (vascular, bone grafting, tumour, selected medial-column plating); the internervous plane (vastus medialis/adductors), the contents of the adductor canal, and the protection of the superficial femoral vessels and saphenous nerve are taught identically across the major anatomical and surgical texts; and for vascular indications the exposure is planned and executed jointly with a vascular surgeon, with proximal and distal control obtained before the vessel is opened. In well-resourced centres the approach supports complex vascular reconstruction and tumour resection; in resource-limited settings the same anatomy applies but the approach is used less often because shaft fractures are nailed and the lateral route suffices. The anatomy and the dangers do not change. Consent (globally applicable): discuss bleeding and vascular injury (the superficial femoral vessels), saphenous nerve numbness, weakness of knee extension if the nerve to vastus medialis is injured, haematoma, infection, and the need for vascular surgical support when the indication is vascular.
For the Operative Surgery station you must be able to describe the medial approach systematically: the position and landmarks, the femoral/obturator internervous plane between vastus medialis and the adductors, the contents and danger of the adductor canal, the profunda perforators at the linea aspera, the indications, and the proximal and distal extensions.
Extensile Exposure
The foundational monograph that codified extensile surgical exposures of the limb long bones, including the medial (subsartorial) approach to the femur. It established the principle of exploiting true internervous planes to gain extensile access while preserving muscle innervation, and remains the classic reference for the medial exposure of the femoral shaft and its relationship to the adductor canal.
Surgical Exposures in Orthopaedics: The Anatomic Approach
Describes the medial approach to the femur through the internervous plane between vastus medialis (femoral nerve) and the adductor group (obturator nerve). It identifies the superficial femoral vessels and the saphenous nerve within the adductor (subsartorial) canal as the critical at-risk structures, and details the surface landmarks from adductor tubercle to pubic tubercle, the positioning, and the need to ligate the perforating branches of the profunda femoris.
Gray's Anatomy: The Anatomical Basis of Clinical Practice
Defines the adductor (subsartorial, Hunter's) canal as approximately 15 cm long, running from the apex of the femoral triangle to the adductor hiatus. It gives the canal boundaries (lateral wall vastus medialis, posterior wall adductor longus then adductor magnus, roof sartorius with its fascia) and lists the contents as the superficial femoral artery and vein, the saphenous nerve and the nerve to vastus medialis, with the artery becoming the popliteal artery at the hiatus.
Rockwood and Green's Fractures in Adults
The standard trauma reference for femoral shaft and distal femoral fractures, where the lateral approach is standard and the medial approach is reserved for specific indications. It supports posteromedial bone grafting for femoral nonunion and medial-column buttress plating through a medial exposure when indicated, and emphasises protection of the perforating vessels and the femoral arterial system when working on the medial and posteromedial femoral cortex.
Rutherford's Vascular Surgery and Endovascular Therapy
The standard vascular reference for surgical exposure of the superficial femoral artery through the medial thigh along the adductor canal. It describes proximal extension into the femoral triangle and distal extension to the popliteal artery for complete vascular control, underpinning the common modern indication for the medial femoral approach as vascular access, repair or bypass performed with a vascular surgeon.