Periprosthetic fracture in THA

1. High-Yield Summary

• Periprosthetic femoral fractures around total hip arthroplasty (THA) represent major surgical trauma in increasingly frail populations, carrying a 1-year mortality rate approaching 11% to 14%, equivalent to native geriatric hip fractures.
• The Vancouver Classification directs surgical decision-making based on fracture location (Type A: trochanteric; Type B: around or just distal to the stem; Type C: well below the stem), stem stability, and host bone quality.
• Determining femoral stem stability is the paramount clinical inflection point: Vancouver B1 fractures (solid, well-fixed stem) are treated with open reduction and internal fixation (ORIF) using locked lateral plates, cerclage cables, and optional strut allografts.
• Vancouver B2 (loose stem, adequate bone stock) and B3 (loose stem, deficient bone stock) fractures cannot be treated with osteosynthesis alone and mandate revision arthroplasty; B2 injuries require distal diaphyseal-engaging modular tapered fluted titanium stems bypassing the fracture by at least two canal diameters.
• Intraoperative stem stability assessment via direct mechanical distraction and rotational stress (“the wiggle test”) is mandatory before final osteosynthesis to prevent catastrophic fixation failure of an undetected loose stem.

2. Anatomy

Successful management of periprosthetic fractures around total hip implants requires deep knowledge of proximal femoral osteology, endosteal vascular supply, and adjacent neurovascular corridors.

Proximal Femoral Osteology and Geometry

The proximal femur consists of the femoral head, femoral neck, greater trochanter, lesser trochanter, and the intertrochanteric and subtrochanteric regions. The calcar femorale is a dense vertical plate of cortical bone that originates from the posteromedial femoral shaft and projects toward the greater trochanter. This structure provides critical resistance to compressive and shear loads transferred from the femoral component. Femoral canal morphology is categorized according to Dorr classification:

• Dorr Type A: Narrow diaphyseal canal with thick, dense cortices (“champagne flute” profile), providing optimal press-fit purchase but predisposing to intraoperative hoop-stress burst fractures during broaching and stem seating.
• Dorr Type B: Intermediate cortical thickness with progressive funneling; standard structural response.
• Dorr Type C: Wide cylindrical canal with thin, porous cortices (“stovepipe” profile), common in elderly and osteoporotic patients, which markedly elevates the risk of late periprosthetic fracture around cementless tapered-wedge stems.

Vascular Corridors and Periosteal Preservation

The blood supply of the proximal femur is derived from the medial and lateral femoral circumflex arteries, the ascending and descending branches of the lateral circumflex system, and descending branches of the profunda femoris artery that enter through muscular attachments. After hip arthroplasty, the endosteal blood supply is largely obliterated by intramedullary broaching, reaming, or cement polymerization. Consequently, cortical perfusion relies almost exclusively on periosteal blood flow. Surgical exposure and cerclage cable placement must avoid circumferential subperiosteal stripping, which causes cortical ischemia and substantially increases the nonunion rate.

Internervous Intervals and Neurovascular Danger Zones

The surgical corridor selected for periprosthetic fracture fixation or revision arthroplasty dictates specific anatomical hazards:

• Posterolateral Approach: Exploits the plane between the gluteus maximus (inferior gluteal nerve) and the tensor fasciae latae (superior gluteal nerve). The primary danger zone is the sciatic nerve, which runs immediately posterior to the short external rotators and quadratus femoris. The nerve is particularly vulnerable to retraction injuries, traction neuropraxia when reducing displaced proximal fragments, or direct laceration from sharp fracture spikes.
• Anterolateral / Direct Lateral Approach (Hardinge): Splits the anterior one-third of the gluteus medius and vastus lateralis. The superior gluteal nerve exits the greater sciatic notch and courses between the gluteus medius and minimus, branching approximately 3 to 5 cm proximal to the tip of the greater trochanter. Proximal extension beyond 3 cm risks permanent denervation of the tensor fasciae latae and anterior gluteus medius, causing an intractable Trendelenburg gait.
• Subvastus Corridor (Lateral Femoral Exposure): For lateral plate osteosynthesis, the vastus lateralis is elevated anteriorly from the lateral intermuscular septum. Perforating branches of the profunda femoris artery pierce the septum at roughly regular intervals and must be systematically identified, ligated, or electrocoagulated to prevent brisk arterial bleeding and postoperative compartment hematomas.

3. Pathogenesis and Biomechanics

Periprosthetic hip fractures occur when cumulative torsional, bending, or axial stresses exceed the ultimate tensile or shear strength of the surrounding cortical bone. The presence of a rigid intramedullary metallic prosthesis fundamentally alters the biomechanics of the femur by creating a severe mismatch in elastic modulus between cobalt-chromium (approx. 200 GPa), titanium alloy (approx. 110 GPa), and cortical bone (approx. 18 GPa).

The stem tip constitutes an abrupt structural transition zone and acts as a mechanical stress riser. Low-energy falls from standing height, accompanied by external rotation and torsional torque, concentrate high shear stress at the junction between the rigid stem and the flexible distal diaphysis, generating characteristic spiral or oblique fracture patterns.

Implant fixation geometry substantially influences fracture morphology and timing:

• Cementless Tapered-Wedge Stems: Rely on proximal metaphyseal wedging and hoop-stress generation for initial stability. In osteoporotic or thin-cortex (Dorr Type C) bone, subtle longitudinal split fractures can occur during broaching or stem seating. If unrecognized intraoperatively, early postoperative axial loading causes progressive stem wedging, catastrophic sagittal split propagation, and early stem subsidence (Vancouver B2).
• Cemented Stems: Transmit stress through an intermediate polymethylmethacrylate (PMMA) mantle. Polished taper-slip stems undergo controlled micro-subsidence within the cement mantle to maintain radial compressive load, whereas composite beam stems depend on complete surface bonding. Fractures around cemented stems typically occur late, precipitated by cement mantle fatigue cracking, particle-induced osteolysis, or high-energy trauma.
• Osteolysis and Cortical Thinning: Polyethylene or metal wear debris elicits macropinocytosis and macrophage activation, releasing inflammatory cytokines (IL-1, IL-6, TNF-alpha) and activating the RANK/RANKL osteoclast pathway. Progressive focal endosteal scalloping and cavitation reduce the polar moment of inertia, dramatically lowering the torque required to induce periprosthetic bone failure.

4. Natural History and Epidemiology

Periprosthetic femur fractures represent the third most common indication for revision total hip arthroplasty, following aseptic loosening and periprosthetic joint infection, and are the most common reason for revision within the first 90 days of index surgery.

• Incidence: The reported cumulative incidence ranges from 0.4% to 1.5% following primary cemented THA, 2.0% to 4.5% following primary cementless THA, and 4.0% to 8.0% following revision THA.
• Demographics: Peak incidence occurs in female patients between 75 and 85 years of age. Primary predisposing risk factors include severe osteoporosis, inflammatory arthritis, prior lumbar spine fusion (altering spinopelvic kinematics and ground reaction forces), neuromuscular disease, dementia, and revision surgery with cortical bone defects.
• Prognosis Without Surgical Stabilization: Displaced periprosthetic fractures and unstable stems treated nonoperatively almost invariably progress to fibrous nonunion, severe stem subsidence, recurrent dislocation, permanent loss of ambulatory capacity, and chronic pain. In elderly patients, prolonged recumbency triggers systemic deconditioning, pneumonia, decubitus ulcers, and thromboembolic death. Even with modern surgical intervention, 30-day mortality is approximately 2% to 4%, and 1-year mortality reaches 11% to 14%.

5. Clinical Presentation

History

Patients typically present after a low-energy ground-level fall with sudden, excruciating pain in the thigh, groin, or knee, accompanied by immediate inability to bear weight. The clinician must explicitly probe for:

• Prodromal Symptoms: Pre-existing start-up groin or thigh pain upon rising from a seated position, thigh discomfort during weight-bearing, or progressive limp. Prodromal symptoms indicate pre-fracture stem loosening, micro-instability, or occult osteolysis (strongly pointing toward a Vancouver B2 or B3 rather than an isolated B1 injury).
• Implant Timeline and History: Date and type of index surgery, primary vs. revision implant, history of prior deep wound complications, and presence of other joint arthroplasties.
• Systemic and Fall Risk Profile: Syncope, cardiac arrhythmias, transient ischemic attacks, polypharmacy, and mechanical tripping mechanisms to differentiate fragility falls from medical syncopal episodes.

Physical Examination

Physical examination must begin with visual inspection of the injured limb and systemic evaluation of hemodynamic stability:

• Inspection and Alignment: The affected extremity classically displays shortening, external rotation, and thigh swelling or ecchymosis. Soft tissue tension must be evaluated for signs of tense subfascial hematoma.
• Palpation: Point tenderness and palpable cortical crepitus along the mid-to-distal lateral thigh corresponding to the fracture site.
• Neurovascular Exam: Systematic motor and sensory assessment of the sciatic nerve branches (peroneal: deep peroneal web space sensation, ankle dorsiflexion, and extensor hallucis longus; tibial: plantar sensation and ankle plantarflexion) and femoral nerve (quadriceps contractility and anterior thigh sensation). Distal pulses (dorsalis pedis and posterior tibial) must be palpated and graded.

6. Imaging and Diagnostic Studies

Comprehensive radiographic evaluation is mandatory to determine fracture configuration, assess stem stability, evaluate host bone stock, and exclude concurrent acetabular periprosthetic fractures or pelvic discontinuity.

Plain Radiography (The Gold Standard)

• Anteroposterior (AP) Pelvis and Bilateral Hip Views: Provides baseline comparison with the contralateral hip, allows assessment of abductor musculature, component offset, and leg length discrepancies.
• Full-Length AP and Lateral Femur Radiographs: Essential imaging requirement. The entire length of the femur including the knee joint must be visualized. Standard hip films that cut off the distal stem tip fail to demonstrate distal spiral fracture extensions or previous distal cortical stress risers.
• Comparison with Historical Postoperative Films: Comparing current films with immediate postoperative or routine surveillance radiographs is the single most reliable method to diagnose stem loosening. Key radiographic indicators of component loosening include:
  • Stem subsidence of 2 mm or greater compared with baseline radiographs.
  • Progressive varus or valgus tilt of the femoral stem.
  • Continuous radiolucent lines (> 2 mm) at the bone-implant or bone-cement interface in Gruen zones 1 through 14.
  • Fracture, fragmentation, or complete debonding of the acrylic cement mantle.
  • Pedestal formation or reactive endosteal sclerosis below the stem tip in an unbonded stem.

Computed Tomography (CT) with Metal Artifact Reduction

CT with metal artifact reduction software (MARS) is invaluable in complex fracture patterns. CT clarifies whether the fracture line propagates into the metaphyseal calcar region, details rotational displacement of the fragments, maps pelvic continuity in periacetabular fractures, and quantifies remaining cortical thickness for distal revision fixation.

Laboratory Evaluation & Infection Workup

Periprosthetic joint infection (PJI) must be actively ruled out in all patients presenting with periprosthetic fractures, particularly those with prodromal pain, low-energy atraumatic fractures, or marked osteolysis:

• Serology: Serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP). Note that acute fractures elevate CRP; however, baseline ESR and markedly disproportionate CRP (> 100 mg/L) raise suspicion for active underlying sepsis.
• Joint Aspiration: Mandatory if clinical history, inflammatory markers, or radiographic osteolysis suggest chronic infection. Synovial fluid is analyzed for total nucleated cell count, polymorphonuclear percentage (> 70%), and aerobic/anaerobic cultures.

7. Classification

The Vancouver Classification System, originally described by Duncan and Masri in 1995, is the universally accepted standard for classifying periprosthetic femoral fractures around hip arthroplasties. It stratifies injuries based on anatomical site, stability of the femoral prosthesis, and the quality of surrounding host bone stock.

The Unified Classification System (UCS), described by Duncan and Haddad (2014), expands this framework across all anatomical joints and includes Type D (fracture of an implant), Type E (articular fracture adjacent to implant), and Type F (fracture spanning between two implants, such as an ipsilateral THA stem and total knee arthroplasty femoral component).

8. Treatment and Surgical Management

Medical and Nonoperative Management

Nonoperative management has an extremely limited role in periprosthetic hip fractures, strictly restricted to:

• Nondisplaced or minimally displaced (< 1 cm) Vancouver Type A_G fractures without abductor insufficiency.
• Isolated Vancouver Type A_L fractures where stem stability is unequivocally confirmed.
• Critically ill, bedridden, or moribund patients with prohibitively high anesthetic risk who cannot survive surgical intervention.

Nonoperative treatment consists of 4 to 6 weeks of protected partial or non-weight-bearing with crutches or a walker, coupled with aggressive deep venous thrombosis prophylaxis and close serial radiographic surveillance to detect delayed displacement or occult stem subsidence.

Operative Management: Goals and Algorithmic Execution

The primary goals of operative management are: restoration of femoral length, alignment, and rotation; rigid biomechanical stabilization allowing immediate postoperative mobilization; and definitive revision of any loose or compromised prosthetic components.

• Vancouver Type B1 (ORIF with Locked Plating):
  • Requires an extensive lateral subvastus approach to the femur.
  • Direct fracture reduction and provisional fixation using reduction clamps and cerclage cables.
  • Implantation of a broad, long 4.5 mm periprosthetic locked compression plate spanning from the greater trochanter to the supracondylar distal femur.
  • Proximal fixation around the well-fixed stem is achieved using offset plate holes with bicortical screws anterior/posterior to the stem, unicortical locked screws, or integrated cerclage cable attachments.
  • Distal fixation requires at least 4 to 5 bicortical screws (8–10 cortices) engaging pristine distal diaphyseal and metaphyseal bone.
  • Cortical strut allografts (placed anteriorly or medially 90 degrees to the plate) provide dual-column mechanical support, enhance biological healing, and improve load transfer in osteoporotic bone.
• Vancouver Type B2 (Revision Arthroplasty with Modular Tapered Stems):
  • Requires an extended posterolateral approach, frequently utilizing an extended trochanteric osteotomy (ETO) to facilitate controlled stem extraction, complete cement removal, and anatomical reduction of the proximal femoral tube.
  • Provisional cerclage cables are placed around the proximal fragments and distal to the fracture line prior to reaming to prevent propagation of splits into the intact diaphysis.
  • Distal reaming of the pristine diaphysis to achieve rigid scratch-fit purchase.
  • Implantation of a modular tapered fluted titanium stem that bypasses the most distal fracture line by at least two canal diameters (4 to 5 cm) of circumferential cortical contact.
  • The proximal modular body is selected to independently restore anteversion, vertical offset, and leg length.
  • Cerclage cables are retensioned around the reduced proximal fragments to reconstruct the proximal bone sleeve around the prosthesis.
• Vancouver Type B3 (Complex Proximal Femoral Reconstruction):
  • In active patients with adequate distal bone: long modular tapered stems combined with structural cortical allografts or impaction bone grafting.
  • In low-demand, elderly patients with un-reconstructible proximal bone loss: Proximal Femoral Replacement (PFR) with cemented or uncemented distal modular fixation. PFR significantly shortens operative time, eliminates reliance on union of necrotic fragments, and enables immediate weight-bearing.
  • Dual-mobility bearings or constrained liners are strongly indicated to counteract the high dislocation rate resulting from proximal abductor and capsular deficiency.
• Vancouver Type C (Distal Plate Osteosynthesis):
  • Treated according to standard fracture principles using a retrograde intramedullary nail (if the distance between the stem tip and fracture permits) or a long distal femoral locked compression plate.
  • Critical surgical principle: The plate must extend proximally to overlap the femoral stem by at least two full cortical shaft diameters. Leaving a gap between the plate and the stem tip creates an extreme stress riser that causes early refracture.

Indications and Contraindications

Definitive operative thresholds include:

• Indications for ORIF: Vancouver B1 with verified stem stability; Vancouver C; Vancouver A_G with displacement > 1 cm and significant abductor dysfunction.
• Indications for Revision Arthroplasty: Any Vancouver B2 or B3 fracture; any periprosthetic fracture with pre-existing stem loosening, stem subsidence > 2 mm, or broken cement mantle; failure of prior B1 osteosynthesis.
• Contraindications to ORIF Alone: Unrecognized stem loosening; attempting plate fixation across a loose stem (B2 misclassified as B1) results in mechanical failure rates exceeding 40% to 50%.

9. Outcomes and Survivorship

Modern algorithmic treatment protocols have markedly improved union rates and implant survivorship for periprosthetic hip fractures:

• Vancouver B1 Fractures: Modern locked compression plating with proximal cable-screw options and strategic strut allografting achieves fracture union rates of 90% to 95%, with a mean time to union of 14 to 20 weeks. Reoperation rates for nonunion or hardware failure range from 5% to 9%.
• Vancouver B2 and B3 Fractures: Revision arthroplasty using modular tapered fluted titanium stems achieves fracture union in 92% to 96% of cases and long-term stem survivorship exceeding 90% at 5 to 10 years. In elderly patients managed with proximal femoral replacement (PFR), immediate full weight-bearing is achieved, though 5-year implant survivorship is approximately 80% to 85% due to late loosening or infection.
• Functional Recovery: Functional scores (Harris Hip Score, Parker Mobility Score) show an average decline of 15% to 25% compared to pre-fracture baseline. Approximately 60% to 70% of previously independent community ambulators regain independent walking status, while 30% require upgraded assistive devices (canes or walkers).

10. Complications

Periprosthetic hip fractures carry substantial morbidity, categorized chronologically:

11. Pearls and Pitfalls

Senior arthroplasty surgeons adhere to key technical pearls to navigate dangerous pitfalls:

• The Direct Wiggle Test (Essential Pearl): Never rely solely on static preoperative radiographs to classify a fracture as Vancouver B1. After surgical exposure of the fracture, apply direct rotational and axial distraction force to the femoral prosthesis using a bone hook or punch. If any micromotion is observed between the stem and host bone, the fracture is by definition a Vancouver B2 and requires stem revision.
• Prophylactic Distal Cerclage Cabling: When revising a Vancouver B2/B3 fracture with a modular tapered stem, always place a prophylactic cerclage cable 1 to 2 cm distal to the planned osteotomy or fracture zone before inserting reamers or impacting the stem. This prevents catastrophic hoop-stress splitting of the pristine distal diaphysis.
• Avoiding the “Empty Hole” Stress Riser: When fixing Vancouver B1 or C fractures with lateral plates, ensure the plate overlaps the stem tip by at least two full bone diameters. Never leave empty screw holes adjacent to the stem tip, as stress concentration at unfilled holes triggers early plate fracture.
• Judicious Soft Tissue Stripping: Limit periosteal elevation on the medial and anterior surfaces of the proximal fragments. Strut allografts and plates must be placed with minimal subperiosteal dissection to protect residual periosteal perforators.
• Liberal Use of Dual-Mobility Articulations: Postoperative dislocation is the most frequent mechanical complication following revision for periprosthetic fractures. Utilizing dual-mobility bearings significantly reduces dislocation rates without increasing aseptic loosening.

12. Controversy

Several major controversies persist in the contemporary management of periprosthetic hip fractures:

• ORIF vs. Stem Revision in Borderline Vancouver B1/B2 Fractures: Certain stable fracture patterns with minimal subsidence (< 2 mm) have been treated by some trauma centers with plate osteosynthesis alone. However, national registry data and long-term cohort studies consistently indicate that failure rates exceed 30% when borderline stems are treated with ORIF. Contemporary consensus firmly favors revision arthroplasty whenever stem stability is questionable.
• Modular Tapered Fluted Stems vs. Proximal Femoral Replacement (PFR) in Vancouver B3: Modular fluted stems preserve host bone biology and allow reconstitution of the proximal bone sleeve over time, but require long protected weight-bearing periods and have a risk of nonunion. In contrast, PFR enables immediate full weight-bearing and shortens operative time, making it increasingly popular for low-demand geriatric patients (age > 80 years), despite higher long-term risks of dislocation and infection.
• Routine Strut Allografts vs. Modern Locked Plating Alone in B1 Fractures: Proponents of cortical strut allografts argue that dual-column fixation accelerates biological union and reduces plate strain. Conversely, advocates of modern locked plating with multiple cable-screw attachments argue that allografts increase surgical dissection, risk viral transmission, and add substantial financial expense without showing a statistically significant reduction in nonunion in modern locked series.
• Cemented vs. Cementless Fixation in Primary Arthroplasty for Fragility Patients: Given the elevated risk of early periprosthetic fracture with cementless wedge stems in elderly osteoporotic females (Dorr Type C bone), many international registries and clinical guidelines strongly recommend cemented femoral fixation for primary hip arthroplasty in patients aged 70 years and older.

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

• Abushal MH, Embaby OM, Mersal M et al. Cemented vs uncemented femoral fixation in total hip arthroplasty: A systematic review and meta-analysis of periprosthetic fracture risk. World J Orthop. 2026. doi:10.5312/wjo.v17.i2.115615 [Level I: Systematic Review / Meta-Analysis]
• Mabrouk A, Feathers JR, Mahmood A et al. Systematic Review and Meta-Analysis of Studies Comparing the Rate of Post-operative Periprosthetic Fracture Following Hip Arthroplasty With a Polished Taper Slip versus Composite Beam Stem. J Arthroplasty. 2024. doi:10.1016/j.arth.2023.06.014 [Level I: Systematic Review / Meta-Analysis]
• Gausden EB, Bedard NA, Gililland JM et al. What’s New in Periprosthetic Femur Fractures?. J Arthroplasty. 2024. doi:10.1016/j.arth.2024.04.037 [Level IV: Clinical Review / Practice Consensus]
• Abdel MP, Cottino U, Mabry TM. Management of periprosthetic femoral fractures following total hip arthroplasty: a review. Int Orthop. 2015. doi:10.1007/s00264-015-2979-0 [Level IV: Clinical Review / Cohort Algorithm]
• Wu ES, Cherian JJ, Kapadia BH et al. Outcomes of post-operative periprosthetic femur fracture around total hip arthroplasty: a review. Expert Rev Med Devices. 2015. doi:10.1586/17434440.2015.958076 [Level IV: Clinical Review / Meta-Summary]

15. Master Class Pro-Tip

When approaching a presumed Vancouver B1 periprosthetic femur fracture, the single most critical maneuver is intraoperative mechanical interrogation of the stem under direct visualization. After exposing the fracture site, place a bone hook or punch against the collar or shoulder of the prosthesis and apply aggressive axial extraction and rotational torque. If the stem displays even 1 millimeter of independent toggling or pistoning within the proximal canal, the injury is a Vancouver B2. Attempting osteosynthesis of a loose stem invariably leads to hardware fatigue failure, nonunion, and catastrophic revision. When revising Vancouver B2/B3 fractures, ensure the modular tapered fluted stem engages at least 4 to 5 centimeters (or two cortical diameters) of pristine distal diaphyseal bone, and always place prophylactic cerclage cables distal to the fracture prior to reaming to prevent longitudinal split propagation.

Master Class Surgical Pearl: Intraoperative Stem Stability Interrogation and Distal Bypass Principles in Periprosthetic Hip Fractures