Periprosthetic femoral fracture (hip stem)

Vancouver / UCS IV.3

A, B1–B3, C · around a hip stem

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A fracture of the femur around or below a hip replacement stem. Its incidence rises with every arthroplasty done in an ageing population. The Vancouver classification combines three questions: where is the fracture (trochanters, around the stem, well below it), is the stem still well fixed, and is the bone stock good enough to hold a new implant. Stem stability is the key question, because a loose stem must be revised, not plated. (The model here shows the native femur only; the text describes the stem.)

Periprosthetic femoral fracture around an uncemented hip stem. AP view of a left total hip: fracture lines run along the femoral cortex beside an uncemented stem, a Vancouver B pattern; stem fixation decides between plating (B1) and revision (B2). — Jmarchn, CC BY-SA 3.0, via Wikimedia Commons.

Mechanism

Mostly low-energy falls in elderly patients. Risk factors: osteoporosis, uncemented stems (especially early) and, among cemented stems, polished taper-slip designs, a loose or osteolytic stem, revision surgery, female sex, rheumatoid arthritis. Intraoperative fractures occur while broaching or impacting a press-fit stem.

Clinical findings

Pain, deformity and inability to bear weight after a fall in a patient with a hip replacement.
Ask about pain before the fall (start-up thigh pain suggests a loose stem) and prior infection; check the operation note for the implant type.
Infection must be excluded: CRP, and aspiration if suspected. Many patients are frail: orthogeriatric care from the start.

Imaging

AP pelvis and AP and lateral of the whole femur including the knee.
Compare with previous post-operative films: stem subsidence, cement mantle fracture, radiolucent lines or osteolysis suggest a loose stem.
CT (with metal artefact reduction) for stem fixation and bone stock when unclear; infection markers (CRP) and aspiration if suspected.

AP pelvis and AP and lateral of the whole femur including the knee (a knee replacement below changes the plan).
Compare with previous films: subsidence of the stem, a cement mantle fracture, a radiolucent line around the stem or osteolysis all suggest a loose stem (B2).
CT helps judge stem fixation and bone stock; the final decision on stability is often made in theatre (test the stem under direct vision).

Classification

Vancouver A_G: Greater trochanter fracture (often osteolysis behind it).
Vancouver A_L: Lesser trochanter fracture: check that the calcar and stem fixation are intact.
Vancouver B1: Around or just below the stem, stem well fixed.
Vancouver B2: Around the stem, stem loose, good bone stock.
Vancouver B3: Around the stem, stem loose, poor bone stock or severe comminution.
Vancouver C: Well below the stem tip: treat as a femoral fracture independent of the implant.
UCS (Unified Classification): Extends Vancouver to every joint: adds D (fracture between two implants, e.g. hip and knee), E (fractures of two bones supporting one implant) and F (fracture of the bone articulating with a hemiarthroplasty).

Types shown in 3D

Vancouver A_G: Greater trochanter: often through an area of osteolysis. Abductors pull the fragment up. Fix if displaced more than about 2 cm or if the hip is unstable.
Vancouver A_L: Lesser trochanter pulled off by iliopsoas. Usually harmless, but a large fragment can take the medial calcar with it and loosen the stem.
Vancouver B1: Spiral or oblique fracture around the stem, which is still well fixed (no subsidence, intact cement mantle or bone ingrowth). Treat with a long locking plate and cables spanning the stem.
Vancouver B2: Same level, but the stem is loose (it has subsided or the fracture runs through the cement mantle / proximal bone that held it). Revise to a long distally fixed stem that bypasses the fracture.
Vancouver B3: Loose stem with poor bone stock: the proximal femur is comminuted or eroded. Long tapered fluted revision stem, proximal femoral replacement or allograft–prosthesis composite.
Vancouver C: Well below the stem tip: fix it as a femoral shaft or distal femur fracture, but overlap the stem with the plate so that no unprotected bone is left between implants.

Treatment

Vancouver A: Usually non-operative with protected weight bearing and limited abduction. Fix a greater trochanter displaced more than about 2 cm, or one causing abductor weakness or instability (cable-grip or hook plate, cables, tension band).
Vancouver B1: Open reduction and internal fixation: a long locking plate spanning the whole femur, with cables and locking screws around the stem, ± allograft strut. Overlap the stem by at least two cortical diameters to avoid a stress riser.
Vancouver B2: Revise the stem to a long, distally fixed implant (modular fluted tapered or extensively coated) that bypasses the fracture by at least two cortical diameters, plus cerclage of the proximal fragments. In selected cemented polished taper-slip stems with an intact bone–cement interface, reduction and fixation with cement-in-cement revision is an option.
Vancouver B3: Revision with a long tapered fluted stem if there is enough distal diaphysis to grip; otherwise proximal femoral replacement (megaprosthesis) or an allograft–prosthesis composite. Choose dual-mobility or a constrained liner to lower the dislocation risk.
Vancouver C: Locking plate that overlaps the stem (and any knee implant), to avoid an unprotected segment of bone between two implants; a retrograde nail leaves a gap below the stem and is usually combined with a plate.

Aftercare

Early mobilisation is the goal; weight bearing depends on the construct (often immediate after revision with a distally fixed stem, protected after plating). Thromboprophylaxis, osteoporosis treatment and a fall assessment.

Complications

High 1-year mortality (similar to a hip fracture)
Non-union and plate failure (often from missing a loose stem)
Dislocation after revision
Infection
Refracture at the end of a plate or between implants