Lateral Thigh | Vastus Lateralis Elevation | Perforator Ligation | Femoral NV Protection
Surgical Imaging
The perforating branches of the profunda femoris artery pierce the lateral intermuscular septum to reach the vastus lateralis. These are the major source of bleeding in this approach. Identify, ligate or cauterise each perforator as the muscle is elevated. Uncontrolled bleeding obscures the field and risks haematoma.
The femoral artery, vein and nerve lie in the femoral triangle and course along the medial aspect of the femoral shaft deep to vastus medialis. The approach stays lateral to the femur; the bundle is protected by remaining strictly on the anterolateral surface and avoiding medial penetration.
The fascia lata is the thick fibrous layer enveloping the thigh. It must be split longitudinally in line with the skin incision. Incomplete division prevents adequate retraction of vastus lateralis and limits exposure. Close it securely at the end to prevent muscle herniation.
Vastus lateralis is elevated anteriorly (medially in the surgical field) off the lateral intermuscular septum. The muscle can be split in its substance or elevated subperiosteally from the septum. Subperiosteal elevation is preferred to minimise bleeding and preserve the muscle's neurovascular supply from the femoral nerve.
There is no classical internervous plane because the approach works anterior to the lateral intermuscular septum within the anterior compartment. The femoral nerve supplies all quadriceps including vastus lateralis; the dissection does not cross a nerve plane but relies on careful elevation and perforator control.
The approach extends proximally along the greater trochanter into the Watson-Jones interval between tensor fascia lata and gluteus medius, or distally along the lateral femoral condyle for supracondylar access. Both extensions remain anterior to the intermuscular septum and protect the femoral bundle.
At a Glance
The anterolateral approach to the femoral shaft provides direct access to the lateral and anterior surfaces of the femur for plate fixation, bone grafting and nonunion management. The skin incision lies over the lateral thigh in line with the greater trochanter and lateral femoral condyle. The fascia lata is split, and vastus lateralis is elevated anteriorly from the lateral intermuscular septum. The critical step is systematic ligation of the perforating branches of the profunda femoris artery as they pierce the septum - failure to control these vessels is the most common cause of troublesome bleeding. The femoral neurovascular bundle remains medial and protected provided dissection stays on bone. The approach is extensile proximally and distally and is the workhorse exposure for femoral shaft plating.
LATERALLATERAL FEMUR - Surgical Steps
Hook:LATERAL approach keeps you on the safe side of the femur!
PERF LIGATEPERFORATORS - Danger Points
Hook:PERForators must be LIGATEd early and systematically!
Indications and Approach Selection
Primary Indications:
- Femoral shaft fractures requiring open reduction and plate fixation
- Aseptic nonunion of the femoral shaft with need for direct bone grafting
- Malunion requiring corrective osteotomy and plating
- Pathological fractures requiring curettage and stabilisation
- Anterior bone grafting procedures for delayed union
Why This Approach is Chosen: The anterolateral approach gives excellent access to the lateral and anterior surfaces of the femoral shaft. It allows direct visualisation for reduction, application of a lateral or anterior plate, and placement of anterior bone graft. The femoral neurovascular bundle is safely medial and the approach avoids the posterior compartment structures.
Contraindications:
- Active infection at the surgical site
- Severe soft-tissue compromise over the lateral thigh requiring alternative exposure
- Patient factors precluding supine or lateral positioning
- Isolated medial femoral pathology better addressed by medial approach
Alternative Approaches:
- Lateral approach with vastus lateralis split: Similar but splits muscle substance rather than elevating from septum
- Posterior approach: For posterior cortex access or when lateral soft tissues are compromised
- Minimally invasive percutaneous plating: When indirect reduction is acceptable
- Antegrade or retrograde nailing: When intramedullary fixation is preferred
Internervous Plane
Deep Internervous Plane: There is no true internervous plane in the classic sense. The entire quadriceps (including vastus lateralis) is supplied by the femoral nerve. The dissection proceeds anterior to the lateral intermuscular septum, elevating vastus lateralis from its septal attachment rather than crossing between two differently innervated muscles.
Superficial Dissection: The fascia lata is split longitudinally. The fascia lata itself is innervated by the lateral cutaneous nerve of the thigh proximally and has no motor innervation. The plane is therefore intermuscular rather than internervous.
The anterolateral femoral approach is best described as an intermuscular plane anterior to the lateral intermuscular septum. Vastus lateralis is elevated medially (anteriorly in the wound) from the septum, preserving its femoral nerve branches that enter from the anterior surface. Staying strictly subperiosteal on the femur keeps the medial femoral neurovascular bundle safe. The key technical point is systematic control of the perforating vessels that cross the septum from posterior to anterior.
Structures at Risk in Each Layer:
- Structure
- Lateral cutaneous nerve of thigh
- Protection Strategy
- Identify and preserve if encountered proximally
- Structure
- Perforating vessels
- Protection Strategy
- Ligate as they pierce the septum
- Structure
- Vastus lateralis branches
- Protection Strategy
- Elevate gently, avoid splitting muscle if possible
- Structure
- Femoral neurovascular bundle
- Protection Strategy
- Remain strictly on anterolateral femoral surface
Positioning and Patient Setup
Position: Supine on Radiolucent Table
Pre-positioning Checklist:
- Confirm patient can tolerate supine position (no spinal precautions)
- Pad all pressure points (heels, sacrum, elbows)
- Arms abducted less than 90 degrees or tucked
- Radiolucent table confirmed for full femur fluoroscopy
- C-arm positioned for AP and lateral views of entire femur
Positioning Details:
- Supine with a small bump under the ipsilateral buttock to neutralise femoral rotation
- Affected leg draped free or with a sterile tourniquet high on the thigh
- Knee flexed 10-20 degrees over a bolster to relax the quadriceps
- Full length femur must be accessible from greater trochanter to knee
A high thigh tourniquet is useful for a bloodless field but limits proximal exposure. For fractures near the lesser trochanter consider tourniquet-free surgery or a sterile tourniquet applied after the proximal dissection is complete.
Alternative Positioning:
- Lateral decubitus allows gravity retraction of vastus lateralis but makes fluoroscopy more difficult
- Some surgeons prefer lateral for combined anterior and posterior access
Surface Anatomy and Landmarks
Key Bony Landmarks:
- Greater trochanter - palpable prominence at the proximal end of the incision
- Lateral femoral condyle - palpable at the distal end of the incision
- Linea aspera - posterior ridge palpable through vastus lateralis once elevated
Key Soft Tissue Landmarks:
- Iliotibial band / fascia lata - thick palpable band on the lateral thigh
- Vastus lateralis - the most lateral quadriceps muscle belly
- Lateral intermuscular septum - felt as a firm plane once fascia is opened
Incision Planning:
- Longitudinal incision along the lateral thigh from greater trochanter to lateral femoral condyle
- Length determined by fracture extent - typically 15-25 cm for mid-shaft plating
- Centre the incision over the fracture site using fluoroscopy
- Stay anterior to the posterior femoral line to avoid the posterior compartment
Surgical Technique
Patient Position Supine on radiolucent table with ipsilateral buttock bump. Leg draped free. Tourniquet optional.
Surface Landmarks Greater trochanter proximally, lateral femoral condyle distally, lateral intermuscular septum in the mid-thigh. Incision is longitudinal and centred over the fracture using fluoroscopic guidance.
Fascia Lata The thick fascia lata is incised in line with the skin incision. Self-retaining retractors are placed under the fascia edges to expose the vastus lateralis.
Structures at Risk
The most important bleeding risk. These vessels pierce the lateral intermuscular septum from posterior to anterior to supply vastus lateralis. They must be identified and ligated as the muscle is elevated. Uncontrolled bleeding leads to haematoma and obscures the operative field.
Lie in the femoral triangle and descend along the medial femur deep to vastus medialis. Protected by staying strictly on the anterolateral femoral surface and avoiding any medial penetration. The bundle is never visualised in a correctly performed approach.
Branch of profunda femoris encountered proximally near the greater trochanter. May require ligation during proximal extension. Does not need repair if ligated.
May be encountered in the proximal incision. Preserve if possible to avoid lateral thigh numbness. Division causes only sensory loss.
Bleeding Management:
- Systematic ligation of perforators before muscle elevation
- Bone wax for metaphyseal bleeding
- Packing with haemostatic agents if brisk bleeding encountered
- Avoid blind deep clamping near the medial femur
Extensile Modifications
Proximal Extension (Watson-Jones Interval):
- Extend incision proximally along the greater trochanter
- Develop the interval between tensor fascia lata (superior gluteal nerve) and gluteus medius (superior gluteal nerve)
- Allows access to the femoral neck and subtrochanteric region
- Useful for long plates or combined neck-shaft fractures
Distal Extension:
- Extend along the lateral femoral condyle
- Split the iliotibial band and elevate vastus lateralis from the condyle
- Provides access to supracondylar fractures and the lateral distal femur
- Can be combined with a lateral parapatellar arthrotomy if intra-articular extension
Combined Approaches:
- Rarely needed for isolated shaft fractures
- May combine with a medial approach for complex segmental injuries
- Posterior approach if posterior cortex comminution requires direct access
Complications
Intra-operative Complications:
- Prevention
- Identify and ligate early
- Management
- Pressure, ligation, avoid blind clamping
- Prevention
- Stay strictly subperiosteal
- Management
- Immediate vascular repair, document
- Prevention
- Centre incision over fracture, extend as needed
- Management
- Extend proximally or distally
- Prevention
- Secure fascia lata closure
- Management
- Re-explore and repair fascia if symptomatic
Post-operative Complications:
- Incidence
- 3-5%
- Prevention
- Meticulous haemostasis, drain if needed
- Treatment
- Aspiration or evacuation
- Incidence
- 1-3%
- Prevention
- Prophylactic antibiotics, soft tissue care
- Treatment
- Debridement, antibiotics
- Incidence
- 5-10%
- Prevention
- Stable fixation, bone graft
- Treatment
- Revision plating or nailing
- Incidence
- 5-10%
- Prevention
- Accurate reduction, long plate
- Treatment
- Corrective osteotomy
- Incidence
- 10-15%
- Prevention
- Early ROM, physiotherapy
- Treatment
- Manipulation under anaesthesia
Uncontrolled perforator bleeding occurs in up to 10 percent of cases when the vessels are not ligated systematically. Most resolve with packing and pressure, but return to theatre for haematoma evacuation occurs in 2-3 percent. Permanent femoral nerve or vessel injury is rare (less than 1 percent) when the plane is maintained strictly on bone.
Post-operative Care
Immediate Post-operative:
- Neurovascular check documenting femoral nerve function (quadriceps contraction, knee extension)
- Wound inspection
- Knee immobiliser or hinged brace for comfort
- Elevate limb above heart level
Weight Bearing Protocol:
- Touch weight bearing or partial weight bearing for 6-12 weeks depending on fracture stability and fixation
- Progression based on radiographic healing
- Crutches or walker required
Range of Motion:
- Early passive and active-assisted knee ROM as pain allows
- Goal: 0-90 degrees by 2 weeks, full ROM by 6 weeks
- Quadriceps strengthening begins early
Follow-up Schedule:
- 2 weeks: Wound check, suture removal
- 6 weeks: Radiographs, assess healing, progress weight bearing
- 12 weeks: Radiographs, confirm union, full weight bearing
- 6 months: Clinical and radiographic review
- 1 year: Final assessment
DVT Prophylaxis:
- LMWH or aspirin per institutional protocol
- Duration until mobile (minimum 2-4 weeks)
Evidence Base
Key Evidence Summary
The anterolateral approach is the standard exposure for open plating of femoral shaft fractures when intramedullary nailing is contraindicated. Systematic perforator ligation reduces bleeding complications. Long-term outcomes are excellent with anatomic reduction and stable fixation.
MCQ Practice Points
Q: What is the most important bleeding structure encountered during the anterolateral approach to the femoral shaft? A: The perforating branches of the profunda femoris artery pierce the lateral intermuscular septum. They must be identified and ligated as vastus lateralis is elevated. Uncontrolled bleeding is the most common intra-operative problem.
Q: How is the femoral neurovascular bundle protected during this approach? A: By remaining strictly subperiosteal on the anterolateral femoral surface and never penetrating medially. The bundle lies deep to vastus medialis on the medial side of the femur and is not visualised when the plane is correct.
Q: Is there a true internervous plane in the anterolateral femoral shaft approach? A: No. The entire quadriceps including vastus lateralis is supplied by the femoral nerve. The dissection is anterior to the lateral intermuscular septum and relies on muscle elevation rather than crossing a nerve plane.
Q: How can the anterolateral approach be extended proximally? A: Extend along the greater trochanter into the Watson-Jones interval between tensor fascia lata and gluteus medius. This gives access to the femoral neck and subtrochanteric region while remaining anterior to the intermuscular septum.
Q: What procedures are commonly performed through the anterolateral femoral shaft approach? A: Open reduction and plating of femoral shaft fractures, anterior bone grafting for nonunion, corrective osteotomy for malunion, and curettage of pathological lesions. It is ideal when direct reduction and stable plate fixation are required.
Guidelines, Registries & Global Practice
The anterolateral approach to the femoral shaft is used worldwide for plate fixation when intramedullary nailing is not feasible. Principles are consistent across FRCS, FRACS, EBOT, ABOS and other examination systems.
Side-by-side principles (where guidance converges): AO Foundation recommends anatomic reduction and stable fixation for femoral shaft fractures when plating is chosen. BOA/BOAST guidance emphasises soft-tissue handling and early mobilisation. OTA/AAOS stress restoration of length, alignment and rotation.
Registry evidence: Population incidence of femoral shaft fractures is approximately 10-15 per 100,000 per year. Plate fixation outcomes show greater than 90 percent union when anatomic reduction is achieved. Nonunion rates are higher with atrophic patterns and are reduced by bone grafting.
Global practice variation: In high-resource settings, locking plates and minimally invasive techniques are common. In resource-limited settings, standard compression plates and open techniques remain effective when the same principles of reduction, perforator control and stable fixation are followed.
Consent (globally applicable): Discuss bleeding from perforators, infection (1-3 percent), nonunion (5-10 percent), malunion, knee stiffness, and the need for protected weight bearing for 6-12 weeks.
For the Orthopaedic Operative Surgery station you must describe the anterolateral femoral shaft approach systematically: lateral thigh landmarks, fascia lata splitting, vastus lateralis elevation from the lateral intermuscular septum, systematic ligation of perforating vessels, protection of the medial femoral neurovascular bundle by staying on bone, and the extensile options proximally and distally.
Exam Viva Scenarios
Practise clinical reasoning and management decisions out loud
“A 35-year-old motorcyclist sustains a closed femoral shaft fracture unsuitable for nailing due to a narrow canal. CT confirms a transverse mid-shaft pattern. How would you approach fixation?”
“A 42-year-old has an atrophic femoral shaft nonunion 9 months after intramedullary nailing. You plan to remove the nail and perform plate fixation with anterior bone grafting. Describe your surgical approach and key steps.”
“You are asked to describe how you would extend the anterolateral femoral shaft approach proximally and distally, and name the structures at risk during these extensions.”