Periprosthetic Fractures Around Total Hip Arthroplasty

Periprosthetic femoral fracture is now among the top 3-4 reasons for THA revision across the major joint registries (NJR, AJRR, AOANJRR, Swedish/Nordic). Incidence is rising globally with ageing populations, the dominance of uncemented stems and the growing cumulative pool of primary THAs.

Intraoperative fracture. The technical risks are revision surgery (4-7% risk), uncemented press-fit stem insertion, undersized canal preparation and excessive impaction force. The patient risks are rheumatoid arthritis, severe osteoporosis and anterior femoral cortical defects.

Postoperative fracture. On the implant side, the risks are aseptic loosening with osteolysis, stress shielding with cortical thinning, and a retained cement mantle. On the patient side, they are age over 70, female sex (2.5 times the risk) and frequent falls.

Stress shielding. Rigid metallic stems transfer load distally, bypassing the proximal femur. The proximal femur adapts by resorbing bone (Wolff's law), and the resulting cortical thinning and osteopenia significantly increase the risk of fracture from minor trauma.

Bone quality. Wear debris induces cytokine-mediated bone loss, which is osteolysis. A cortex less than 4mm thick increases fracture risk exponentially, and osteopenia is common in the THA population.

Danger zones. Three sites, each with its own cause:

• Anterior cortex at the apex of the femoral bow, a common perforation site
• Proximal lateral cortex, at risk from aggressive broaching
• Calcar, with varus stem malposition

Prevention. Choose the stem, its fixation and the insertion technique from femoral morphology and patient risk. Prophylactic cerclage is selective, not routine for every fragile femur.

Femoral: Vancouver. A descriptive framework based on location, stem status and bone stock. It does not encode host, infection, implant design or fracture morphology, so each type gives a usual direction that those factors can change.

Acetabular: modified Petersen. Acetabular fractures are described by timing and cup stability.

History. Establish the mechanism, a low-energy fall or higher-energy trauma. Prodromal thigh or groin pain suggests loosening. Record pre-injury function, from independent to bedbound, and comorbidities such as osteoporosis, rheumatoid arthritis and steroid use.

Examination. Look for shortening, rotation and swelling, and feel for tenderness and crepitus. A sciatic and femoral nerve check is mandatory, and systemic signs of infection or sepsis are sought.

Radiographs. Obtain an AP pelvis and orthogonal femoral views that include the entire fracture, the implant and the planned fixation or revision zone. Add full-length imaging for distal extension, other implants, deformity or long construct planning. The rule is coverage of the complete injury and every implant or stress riser relevant to the construct, not a mandatory full-length film.

CT. Metal-artefact-reduction CT is used selectively, for occult extension, comminution, bone stock or osteolysis, acetabular or pelvic involvement, or complex revision planning.

Infection work-up. Infection can present with fracture, loosening or osteolysis. ESR/CRP, aspiration and intraoperative cultures and histology are selected from the symptoms, the wound, osteolysis or loosening, prior infection and operative findings, rather than treated as mandatory clearance tests. Normal markers do not exclude infection, and abnormal markers are nonspecific after trauma.

Distinguishing a stable B1 from a loose B2 is the single most important decision in this topic. The signs are read against a standard map, the Gruen zones, using defined loosening criteria.

Gruen zones. The femoral component is divided into seven zones on the AP film, numbered 1-7 from the lateral shoulder at the greater trochanter, down the lateral cortex to the stem tip and back up the medial cortex, with matching zones on the lateral view. They give a reproducible language for where a lucency, osteolysis or debonding sits.

Cemented stems: the Harris criteria. A progressive or circumferential lucency is the key signal. Read subsidence against the design, because a polished taper-slip stem may subside within an intact cement mantle by design (see Controversies).

• Definite - stem migration or subsidence, or a fractured cement mantle
• Probable - a continuous radiolucent line at the cement-bone interface around the entire stem
• Possible - a lucent line over 50 to 100% of the interface

Uncemented stems. Loosening is suggested by subsidence or migration on serial films, a continuous reactive line around a porous surface, and a distal pedestal with no proximal bone ongrowth. Spot-welds (endosteal bone bridging to the porous coating) and absence of migration indicate a stable, osseointegrated stem.

When the films stay equivocal. Compare against serial and immediate-postoperative films whenever possible. If the radiographs remain equivocal, test the stem directly at operation before committing: a loose stem fixed as a B1 fails. The selected B2 fixations described under Surgical Technique are a deliberate choice around specific cemented-stem mechanics, not this error.

The painful THA with a possible fracture must be distinguished from other causes of acute or progressive hip/thigh pain. The two errors that fail candidates are missing infection (septic loosening masquerading as fracture) and missing occult loosening in an apparently intact femur.

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The decision. Stem stability materially changes the reconstruction, but host, infection, stem design, reducibility, fracture morphology and surgical burden can modify the operation. Do not reduce treatment to B1 ORIF versus B2 revision.

Non-operative or limited goals. Observation or protected mobilisation may suit selected stable trochanteric or minimally displaced patterns, very frail or nonambulatory patients, or palliative goals. Loading, imaging and escalation depend on displacement, pain, function and construct, not a fixed 5 mm or 6-12 week rule.

Intraoperative fracture is defined by location, propagation, component stability and bone, not by one cable recipe. Do not assume every calcar crack needs one cable or every split needs a stem two cortical diameters longer.

The sequence. Stop, define the full pattern and component stability, then stabilise the demonstrated deficit:

1. Stop the manoeuvre that caused concern, expose and inspect as needed, and image the relevant extent of femur and implant.
2. Determine whether the component remains stable and whether seating or removal will propagate the fracture.
3. A limited stable calcar or trochanteric crack may be treated with cerclage, screw or plate fixation, but pattern and stem stability can require a different stem, longer fixation or fracture reconstruction.
4. Diaphyseal or distal propagation may require a plate, a revision stem or both; bypass and overlap are individualised.
5. Re-test implant and fracture stability before closure, and set loading from the actual construct.

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Early. Infection, dislocation, VTE, bleeding, wound problems and nerve injury depend on host, exposure, revision burden and implants. Dual mobility or constrained bearings and cerclage are selective risk-management tools, not automatic.

Late. Nonunion or malunion, loosening, stem subsidence, refracture or stress concentration, and hardware failure should be analysed by biology, alignment, implant stability and construct, not assigned one Vancouver percentage.

Aftercare follows host and construct.

Loading. Mobilise early, with weight-bearing prescribed from stem fixation, fracture and plate stability, bone quality, soft-tissue repair and patient ability. Some constructs permit weight-bearing as tolerated and others require temporary protection.

Precautions and prophylaxis. Use hip precautions only for the surgical approach, component instability and individual dislocation risk. Select VTE prophylaxis from fracture and arthroplasty guidance, bleeding risk, renal function and local protocol rather than a universal 35 days.

Surveillance. Monitor the wound, infection, alignment, union and callus, stem subsidence or loosening, hardware and joint stability at decision-relevant intervals.

Bone health. Treat falls, nutrition, osteoporosis and its secondary causes, and rehabilitation globally. Vitamin D, calcium and drug choice and timing follow measured deficiency, renal function and bone-health guidance, not fixed targets or waiting for radiographic union.

Outcome depends on frailty and comorbidity, pre-fracture mobility, infection, morphology, implant stability, bone stock, reconstructive burden, union and complications. Vancouver subtype alone does not provide a reliable union, revision or functional-return percentage.

Counselling. Counsel from the patient's baseline and the chosen operation. Many need aids or do not regain prior mobility, but no universal six-to-twelve-month endpoint applies.

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Registries consistently identify rising fracture burden and higher risk with some uncemented stems in older/frail femora, but treatment evidence remains observational and implant-era dependent. No global guideline supplies a complete B1/B2/B3 operation table.

Related pages: THA Aseptic Loosening, THA Wear and Osteolysis, Revision THA, Femoral Impaction Bone Grafting, and Periprosthetic Hip Fracture.