Revision THA Exposure – Anterolateral Approach

Archival Presentation Notice: This article modernizes the multimedia presentation “Anterolateral Approach to the Hip: And How to Make it Extensile” originally presented by David G. Lewallen, MD (Mayo Clinic). The historical Flash lecture has been reconstructed into the synchronized video slide presentation above, with the original file preserved in the digital archives (Exposure_Anterolateral_Approach_Lewallen.swf).

1. High-Yield Summary

The anterolateral approach (Watson-Jones corridor and its direct lateral modifications) provides exceptional anterior hip stability and direct visualization of the anterior column, anterior acetabular wall, and proximal femur in revision total hip arthroplasty (THA). In complex revision scenarios marked by extensive osteolysis, well-fixed ingrown femoral stems, cemented mantles, or severe proximal bone loss, standard intermuscular intervals become restrictive. Converting the standard anterolateral corridor into an extensile exposure—via an anterior capsular release, vastus lateralis reflection, trochanteric slide, or extended trochanteric osteotomy (ETO)—enables collinear access along the femoral diaphysis while preserving the vital continuity of the abductor-vastus soft-tissue sleeve.

• Primary Clinical Indication: Revision total hip arthroplasty requiring reconstruction of the acetabulum and/or femur in patients with anterior instability risk, deficient posterior soft tissues, or failed prior anterolateral procedures.
• Critical Technical Move: Maintaining the uninterrupted anatomical continuity between the gluteus medius proximally and the vastus lateralis distally during trochanteric osteotomy to prevent proximal migration and preserve abductor vascularity.
• Catastrophic Error to Avoid: Proximal dissection extending more than 3 to 5 cm cephalad to the greater trochanter tip within the abductor mass, which denervates the anterior gluteus medius and tensor fasciae latae via superior gluteal nerve neurotmesis.

2. Indications and Contraindications

Absolute Indications

• Revision THA in patients with recurrent posterior instability or high dislocation risk where posterior capsular integrity is irrevocably compromised.
• Femoral component revision requiring extraction of well-fixed cementless porous-coated or cemented stems via collinear distal osteotomy.
• Management of periprosthetic proximal femoral fractures (Vancouver B2 and B3) requiring simultaneous fracture reduction, implant extraction, and bypass diaphyseal fixation.
• Reconstruction of extensive anterior and superior acetabular bone deficiencies (Paprosky Type IIB, IIC, and III) requiring augment or cage reconstruction.

Relative Indications

• Prior surgical intervention through an anterolateral or direct lateral incision where existing surgical scars should be incorporated.
• Two-stage exchange arthroplasty for periprosthetic joint infection (PJI) requiring aggressive radical debridement of anterior soft-tissue spaces and complete cement mantle removal.

Contraindications

• Preexisting complete abductor deficiency or irreversible superior gluteal nerve palsy where preservation of posterior hip structures is paramount.
• Massive posterior column or posterior wall acetabular defects (Paprosky Type IIIA/IIIB with posterior pelvic discontinuity) where posterior visualization via a posterior extensile approach is mandatory.
• Severe active soft-tissue infection or necrotic tissue envelopes directly overlying the anterolateral aspect of the hip.

3. Surgical Anatomy and Internervous Planes

The standard Watson-Jones approach exploits the intermuscular interval between the tensor fasciae latae (TFL) anteriorly and the gluteus medius posteriorly. Because both muscles receive innervation from the superior gluteal nerve (L4, L5, S1), this interval is an intermuscular interval rather than a true internervous plane. Dissection must strictly respect the anatomical boundaries of the nervous supply to prevent denervation of the abductor complex.

Key Anatomical Structures

• Superior Gluteal Nerve: Emerges through the greater sciatic notch superior to the piriformis muscle, running laterally between the gluteus medius and gluteus minimus. Its distal branch arborizes into the tensor fasciae latae approximately 3 to 5 cm proximal to the tip of the greater trochanter. Cephalad extension beyond this safety margin produces permanent abductor denervation and intractable Trendelenburg gait.
• Lateral Femoral Circumflex Artery (LFCA): The ascending branch crosses the anterior aspect of the femoral neck and intertrochanteric line beneath the rectus femoris and tensor fasciae latae. It must be proactively identified, clipped, or electrocoagulated during anterior capsular mobilization to prevent brisk retraction hemorrhage.
• Femoral Neurovascular Bundle: Located anterior and medial to the hip capsule, separated by the iliopsoas tendon and reflected head of the rectus femoris. Retractors placed over the anterior acetabular rim must remain in direct contact with bone deep to the capsule to avoid traction or compression injury to the femoral nerve.
• Abductor-Vastus Continuum: Fibers of the gluteus medius and vastus lateralis merge into a dense tendinous aponeurosis over the lateral surface of the greater trochanter. Preserving this functional continuum during trochanteric osteotomies maintains active compression across the osteotomy site during postoperative muscle contraction.

4. Preoperative Planning and Templating

Revision surgery through an extensile anterolateral approach demands comprehensive radiographic assessment and meticulous instrumentation logistics to address anticipated skeletal deficiencies and implant extraction requirements.

Imaging Modalities

• Plain Radiographs: Full-length standing bilateral anteroposterior (AP) pelvis, AP and cross-table lateral of the affected hip, and full-length femoral views. Assess center of rotation, leg-length discrepancy, trochanteric morphology, cement mantle boundaries, stem-to-cortex bonding, and Paprosky classification for acetabular and femoral defects.
• Computed Tomography (CT) with Metal Artifact Reduction (MARS): Crucial for evaluating 3D acetabular column loss, retroacetabular osteolysis, pelvic discontinuity, and femoral cortical thinning. Cross-sectional views reveal the rotational alignment of well-fixed components and guide osteotomy planning.

Equipment Checklist

• Universal implant extraction systems (slap hammers, flexible osteotomes, high-speed carbide burrs, ultrasonic cement removal wands).
• Deep hip retractor sets: Curved blunt Hohmann retractors, spiked anterior acetabular retractors, double-angled Charnley retractor frames, and narrow femoral lever elevators.
• Cable and cerclage fixation systems: Cobalt-chrome or titanium monofilament and braided cables, cable passers, tensioners calibrated to 40–50 Nm, and crimp locking clips.
• Revision implants: Modular tapered splined titanium stems, porous-coated cylindrical stems, modular dual-mobility acetabular systems, porous metal trabecular augments, and structural reconstruction cages.

5. Patient Positioning and Room Setup

Stable, reproducible positioning is required to facilitate intraoperative limb manipulation (adduction, external rotation, extension) and clear fluoroscopic visualization when creating an extended osteotomy.

Operating Room Configuration

• Lateral Decubitus Position: Preferred for revision cases requiring extensile femoral access. The pelvis is locked perpendicular to the operating table using rigid pubic and sacral peg supports. Ensure the dependent axilla is protected with a padded axillary roll and the peroneal nerve of the down leg is free from pressure.
• Sterile Draping Corridor: The entire operative limb is prepped and draped free with a sterile stockinette and elastic wrap from the toes to the iliac crest. Sterile drapes must expose the anterior superior iliac spine (ASIS), greater trochanter, and the lateral femoral shaft down to the knee joint.
• Fluoroscopy Clearance: Position the C-arm base on the contralateral side with unobstructed anteroposterior and cross-table lateral trajectories across the femoral diaphysis.

6. Standard Anterolateral (Watson-Jones) Approach

The standard exposure provides baseline access to the hip joint before implementing extensile modifications.

• Skin Incision: Begin 3 to 4 cm distal and posterior to the ASIS, extend curved over the anterior third of the greater trochanter, and continue straight distally along the anterior border of the femoral shaft for 10 to 15 cm.
• Deep Fascial Incision: Incise the fascia lata longitudinally over the femoral shaft, extending proximally into the interval between the posterior margin of the tensor fasciae latae and the anterior margin of the gluteus medius.
• Intermuscular Interval: Bluntly split the interval with finger dissection. Identify and electrocoagulate the ascending branches of the lateral femoral circumflex vessels crossing the operative floor.
• Capsular Exposure: Retract the TFL anteromedially and the gluteus medius posterolaterally. Incise the reflected head of the rectus femoris off the anterior hip capsule. Perform a generous inverted T-shaped or H-shaped anterior capsulotomy to expose the femoral neck and acetabular margin.

7. Extensile Exposure Options

When the standard Watson-Jones corridor is restricted by contracture, extensive scarring, or the need for distal femoral instrumentation, specific extensile strategies must be applied sequentially.

8. Step-by-Step Operative Technique for Revision Exposure

Executing an extensile anterolateral exposure requires precise sequential execution to maximize visualization while preserving vascular and mechanical tissue integrity.

Step 1: Fascial Extension and Vastus Lateralis Reflection

Extend the fascial incision distally along the iliotibial band to the junction of the middle and distal thirds of the femur. Incise the fascia overlying the vastus lateralis. Reflect the posterior border of the vastus lateralis anteriorly off the lateral intermuscular septum. Coagulate profunda femoris perforating vessels immediately as they penetrate the septum to maintain a bloodless surgical corridor.

Step 2: Trochanteric Slide Execution

When acetabular exposure is obstructed, perform a trochanteric slide. Mark an osteotomy plane from the posterior superior border of the greater trochanter obliquely to the vastus tubercle. Pass a Gigli saw or oscillating saw blade from posterior to anterior under cooling irrigation, exiting at the vastus ridge. Mobilize the osteotomized trochanteric fragment anteriorly along with its continuous attached sleeve of gluteus medius and vastus lateralis. Retract the fragment anteriorly with a sharp Hohmann retractor positioned over the anterior acetabular rim.

Step 3: Extended Trochanteric Osteotomy (ETO) Creation

For femoral component extraction or severe proximal deformity, convert to an ETO. Determine osteotomy length based on the distal extent of the stem or cement mantle, typically 10 to 15 cm distal to the vastus ridge. Drill a transverse relief hole (4.5 mm drill bit) at the anticipated distal apex to eliminate stress risers. Cut the posterior longitudinal cortical border using an oscillating saw blade aligned collinear with the femoral shaft axis. Cut the distal transverse segment across one-third to one-half of the femoral circumference connecting to the relief hole. Lever the anterior osteotomy segment open with wide, thin osteotomes, intentionally cracking the anterior cortex greenstick-style to preserve anterior soft-tissue attachments.

Step 4: Implant Extraction and Canal Preparation

Visualize the stem-bone interface directly under collinear illumination. Disrupt fibrous or bone ingrowth along the lateral, anterior, and posterior aspects using thin flexible osteotomes. Attach the universal stem extraction slap hammer to the stem trunnion and extract the component with axial impaction. Remove remaining cement mantles, distal plugs, or reactive neocortex under direct vision using ultrasonic instruments and reverse-hook curettes.

Step 5: Diaphyseal Fixation and Osteotomy Reconstruction

Place a prophylactic cerclage cable immediately distal to the osteotomy apex prior to reaming to protect against diaphyseal hoop-stress fractures. Ream the distal intact diaphysis cylindrically for at least 4 to 6 cm of scratch fit. Seat a modular tapered splined or cylindrical revision stem past the osteotomy site. Reduce the osteotomy fragment anatomically against the host femur. Secure the fragment using two to three 2.0 mm braided cobalt-chrome or titanium cables with calibrated tensioning (40–50 Nm) and crimping.

Critical Technical Move

The single critical move is pre-placing a prophylactic cerclage cable distal to the ETO apex before reaming or trial reduction. Reaming without apical hoop reinforcement creates devastating distal spiral propagating fractures that compromise diaphyseal stability and jeopardize stem fixation.

9. Management of Severe Acetabular and Femoral Bone Loss

Extensile anterolateral exposure provides direct access to address complex structural defects on both sides of the joint.

• Paprosky Type II and III Acetabular Deficiencies: With the trochanter reflected anteriorly, superior and anterior column deficits are visualized directly. Porous metal augments (titanium or trabecular metal) are shaped to fit structural cavitary/segmental voids and secured with multi-hole trabecular shells.
• Paprosky Type III Femoral Bone Loss: In cases of severe metaphyseal-diaphyseal deficiency where less than 4 cm of intact isthmus remains, distal fixation must be established using fluted tapered modular titanium revision stems that bypass the deficient proximal bone by at least two cortical bone diameters.
• Pelvic Discontinuity: If pelvic discontinuity is recognized intraoperatively, the extensile corridor allows superior exposure of the iliac wing and posterior column for cage bridge plating or dual-column plate fixation combined with porous metal cup-cage constructs.

10. Pearls and Pitfalls

11. Postoperative Rehabilitation Protocol

Postoperative rehabilitation balances structural bone-healing demands against the physiological benefits of early mobility.

12. Complications and Danger Zones

Anticipation of neurovascular danger zones and mechanical pitfalls significantly diminishes revision morbidity.

• Superior Gluteal Nerve Injury: Neurapraxia or transection of the nerve branches within the gluteus medius/minimus interval results in permanent abductor limp (Trendelenburg gait). Prevention requires limiting proximal abductor splitting to less than 3 cm.
• Femoral Diaphyseal Fracture: Cortical perforation or fracture propagation occurs during stem extraction or aggressive broaching. A prophylactic cerclage cable distal to the osteotomy apex is mandatory.
• Trochanteric Nonunion / Migration: Occurs in 1% to 3% of cases following trochanteric slide or ETO, usually secondary to inadequate cable tension, insufficient cable quantity, or premature active abduction. Revision with trochanteric claw plates and structural strut allografts may be required if symptomatic.
• Dislocation: The anterolateral approach historically confers an extremely low dislocation rate (<1.5% to 2.5%) compared to the posterior approach. Ensuring accurate component anteversion, proper abductor tensioning, and anatomical trochanteric reconstruction minimizes instability.
• Heterotopic Ossification (HO): Extensive abductor and capsular dissection increases HO risk. Prophylactic oral NSAIDs (indomethacin 75 mg daily for 10–14 days) or single-fraction radiation therapy (700 cGy) should be considered in high-risk patients.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

14. References

• Younger TI, Bradford MS, Magnus RE et al. Extended proximal femoral osteotomy. A new technique for femoral revision arthroplasty. J Arthroplasty. 1995. doi:10.1016/s0883-5403(05)80182-2 [Level IV: Landmark Technique & Retrospective Case Series]
• Brown TS, McLaughlin RJ, Berry DJ et al. What Is the Survivorship of Revision Surgery Performed for the Chronically Dislocated THA?. Clin Orthop Relat Res. 2019. doi:10.1097/CORR.0000000000000392 [Level IV: Large Retrospective Cohort Series]
• Wyles CC, Hannon CP, Viste A et al. Extended Trochanteric Osteotomy in Revision Total Hip Arthroplasty. JBJS Essent Surg Tech. 2023. doi:10.2106/JBJS.ST.21.00003 [Level IV: Surgical Technique & Clinical Outcomes Review]
• Abwini LZ, Tang A, Zeiman M et al. Immediate Weight Bearing Is Safe Following Combined Extended Trochanteric Osteotomy and Revision Total Hip Arthroplasty. J Am Acad Orthop Surg. 2026. doi:10.5435/JAAOS-D-25-01575 [Level III: Retrospective Comparative Cohort Study]
• Farid YR. The Extended Lesser Trochanteric Osteotomy (ELTO) in Complex Revision Hip Arthroplasty: An Alternative to the Extended Trochanteric Osteotomy (ETO). J Bone Joint Surg Am. 2026. doi:10.2106/JBJS.26.00179 [Level IV: Surgical Technique & Consecutive Case Series]

15. Master Class Pro-Tip

When executing an extended trochanteric osteotomy in severe revision arthroplasty, the most critical surgical maneuver is preserving the uninterrupted anterior continuity of the abductor-vastus continuum. Never disconnect the distal gluteus medius fibers from the proximal vastus lateralis origin. Before making any cortical osteotomy cuts, place a calibrated 2.0 mm cerclage cable 1 to 2 cm distal to the planned osteotomy apex; this prophylactic hoop barrier prevents catastrophic distal fracture propagation during canal preparation. At closure, re-tension all trochanteric cables sequentially after cycling the hip through range of motion, compensating for initial viscoelastic cable stretch and ensuring rigid union.

Master Class Surgical Pearl: Extensile Anterolateral Exposure & Trochanteric Sleeve Preservation