Periprosthetic Fractures



Periprosthetic Fractures





TOTAL HIP ARTHROPLASTY


Femoral Shaft Fractures


Epidemiology



  • Intraoperative: There is a 0.3% up to 5% incidence overall, including cemented and uncemented components.


  • Postoperative: There is a 0.1% incidence.


  • They occur more frequently with noncemented components, with an incidence of 2.6% to 5% to as high as 21% for noncemented revisions.


  • Mortality associated with age >70 years and male sex (men 2.1% vs. 1.2% in women).


Risk Factors



  • Osteopenia: Osteoporosis or bone loss secondary to osteolysis


  • Rheumatoid arthritis


  • Total hip arthroplasty (THA) following failed open reduction and internal fixation (ORIF)


  • Stress risers secondary to cortical defects


  • Revision surgery


  • Inadequate implant site preparation: Large implant with inadequate reaming or broaching may be responsible.


  • Pericapsular pathology: A scarred capsule with inadequate release may result in intraoperative fracture.


  • Loose components: Loose femoral components are responsible for up to 33% of periprosthetic femur fractures.


Surgical Considerations (to Avoid Periprosthetic Fracture During Revision Surgery)



  • Use longer stem prosthesis, spanning twice the bone diameter beyond the defect.



  • Consider bone grafting the defect.


  • Consider strut allograft or plate support.


  • Place cortical windows in an anterolateral location on the femur in line with the neutral bending axis.


  • Leave cortical windows <30% of the bone diameter.


  • Choose the correct starting point for reaming and broaching.


Classification

American Academy of Orthopaedic Surgeons Classification (Fig. 6.1) This divides the femur into three separate regions:

Level I: Proximal femur distally to the lower extent of the lesser trochanter

Level II: 10 cm of the femur distal to level I

Level III: Covers remainder of femur distal to level II

Type I: Fracture proximal to the intertrochanteric line that usually occurs during dislocation of the hip

Type II: Vertical or spiral split that does not extend past the lower extent of the lesser trochanter

Type III: Vertical or spiral split that extends past the lower extent of the lesser trochanter but not beyond level II, usually at the junction of the middle and distal thirds of the femoral stem

Type IV: Fractures that traverse or lie within the area of the femoral stem in level III, with type IVA being a spiral fracture around the tip and type IVB being a simple transverse or short oblique fracture

Type V: Severely comminuted fractures around the stem in level III

Type VI: Fractures distal to the stem tip, also in level III






FIGURE 6.1 American Academy of Orthopaedic Surgeons classification of fractures associated with hip arthroplasty. (Modified from Petty W, ed. Total Joint Replacement. Philadelphia: WB Saunders; 1991:291-314.)







FIGURE 6.2 Vancouver classification scheme for periprosthetic fractures about total hip arthroplasties. (Modified from Duncan CP, Masri BA. Fractures of the femur after hip replacement. In: Jackson D, ed. Instructional Course Lectures 44. Rosemont, IL: American Academy of Orthopaedic Surgeons; 1995:293-304.)


Vancouver Classification (Fig. 6.2)

Type A: Fracture in the trochanteric region

AG: Greater trochanteric region

AL: Lesser trochanteric region

Type B: Around or just distal to the stem

B1: Stable prosthesis

B2: Unstable prosthesis

B3: Unstable prosthesis plus inadequate bone stock

Type C: Well below the stem


Treatment Principles



  • Treatment depends on:



    • Location of the fracture


    • Stability of the prosthesis



      • A loose stem should be revised.


    • Bone stock


    • Age and medical condition of the patient


    • Accurate reduction and secure fixation


  • Options include:



    • Nonoperative treatment: limited weight bearing, brace, cast, or traction


    • ORIF (with plate and screws or cable and/or strut allograft)


    • Revision plus ORIF



Vancouver Type A Fractures



  • These are usually stable and minimally displaced.


  • ORIF is used to maintain abductor function with wide displacement.


  • Revision of acetabular component is indicated with severe polyethylene wear.


Vancouver Type B1 Fractures



  • These are usually treated with internal fixation.


  • Options for fixation include:



    • Wires or cables


    • Plate and screws and/or cables



      • Open versus percutaneous plate placement


    • Cortical onlay allograft—may or may not incorporate


    • Combination


  • Long-term results depend on:



    • Implant alignment


    • Preservation of the periosteal blood supply


    • Adequacy of stress riser augmentation


Vancouver Type B2 Fractures



  • Revision arthroplasty and ORIF are used.


  • Choice of implant includes:



    • Uncemented prosthesis



      • Extensive coated long-stem curved prosthesis


      • Fluted long-stem prosthesis


      • Modular implants


    • Cemented prosthesis


Vancouver Type B3 Fractures



  • No sufficient bone stock supports the revision prosthesis.


  • Options include:



    • Proximal femoral reconstruction



      • Composite allograft


      • Scaffold technique


    • Proximal femoral replacement


  • Treatment depends on:



    • The age of the patient


    • The severity of the bone defect


    • The functional class of the patient


Vancouver Type C Fractures



  • Treat independently of the arthroplasty.


  • Use a plate and screws and/or cables, usually without a strut allograft.


  • Do not create any new stress riser—bypass stemmed implant.

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Jun 17, 2016 | Posted by in ORTHOPEDIC | Comments Off on Periprosthetic Fractures

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