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Perspective

Periprosthetic femoral fractures after total hip arthroplasty Total hip arthroplasty (THA) is an effective surgery with relatively low probability of complications. However, periprosthetic femoral fracture is a potentially devastating complication, with the reported incidence varying between 0.1% and 18%.1 Periprosthetic femoral fracture is associated with high rate of postoperative complications, often showing poor clinical result and increased mortality rate.2 As more periprosthetic fractures around THAs are encountered, it requires good understanding, accurate classification and subsequent treatment decisions taken accordingly.3 A look at risk factors can provide an insight into the preventive aspects and taking precautionary steps would minimize periprosthetic fractures after THA and its complications.

Epidemiology of periprosthetic femoral fractures after THA

Dr. Sanjib Kumar Behera MS (Ortho), DNB (Rehab), ISAKOS (France), DPMR Consultant Orthopaedic Surgeon

The incidence of periprosthetic femoral fractures following THA, though difficult to determine due to problems with long-term follow-up, varies by more than 10-fold, depending on clinical situation. Incidence is much higher after revision surgery than primary THA and is higher with use of uncemented stems. Intraoperative fractures are more common in these cases due to a need for tight press fit and force required to obtain such a fit. Rates reportedly varied from 4.1% to 27.8% after uncemented THA, as compared to <3% with use of cemented stems.4

Risk factors for periprosthetic femoral fractures Bony pathologies / deformities Higher risks for intraoperative fractures exist in rheumatoid arthritis than osteoarthritis, probably due to osteopenia / osteoporosis, and in cases of increased bone fragility (osteomalacia, Pagetâ&#x20AC;&#x2122;s 3


disease, osteopetrosis, and osteogenesis imperfecta, etc). Deformities of proximal femur, especially with a narrow medullary canal (e.g. secondary degenerative joint disease after developmental dislocation of hip) are an increased risk. Improper fit or inadequate insertion or poor removal of cement or bony shelf may also lead to fracture.

Cortical perforation / revision surgery Revision surgery is associated with a higher risk of fracture than primary THA. Fractures occur during hip dislocation, cement extraction, or reaming through old cement. Cortical perforation during THA is a risk factor with incidence seen to be between 0.4% and 4%. Cortical penetration and extruded cement, not treated properly, were seen to be substantial risk factors for femoral stress fractures, especially in revision surgeries. Sudden onset of pain leads to suspicion of loosening or infection in such cases.5 A wider exposure is recommended in patients at risk, and longer stem or with a cortical onlay allograft strut and cerclage wire fixation may be used to minimize perforation.5

Aseptic loosening / osteolysis Loosening of the prosthesis with cortical bone loss and stress risers within the cortex, including old screw holes, ends of plates, or impingement of loose stem against lateral femoral cortex add to risk. Femoral osteotomy done in THA for proximal femoral deformity is associated with high risk. Localized osteolysis is associated with periprosthetic femoral fractures.5

Classification Classification of periprosthetic femoral fractures guides treatment, estimates prognosis, and indicates likely complications. Several factors are considered while evaluating periprosthetic femur fractures (Box 1). Several different classifications have been suggested by various authors for periprosthetic femoral fractures with hip prostheses, depending on fracture location, time of fracture (intraoperative or postoperative), status of implant (loose or stable), and type of implant (cemented or uncemented). However, the Vancouver classification6 is considered 4

Perspective

Box 1. Factors affecting management of periprosthetic femoral fractures: Patient characteristics •

General factors

Age

Health

Tobacco use

Immunosuppression

Local factors •

Previous irradiation

Osteoporosis

Osteolysis

History of previous fracture

Presence of other stress risers

Fracture characteristics

Location

Pattern

Implant characteristics •

Stability

Well fixed

Loose

Type of implant •

Press-fit vs. cemented

Short vs. long stem

More than one implant

standard and has been rigorously evaluated with acceptable and consistent reliability and validity.7 The Vancouver classification is based on fracture location, quality stem fixation, and the quality of bone. Treatment decisions are guided by correct classification of fracture. The Vancouver classification divides periprosthetic femoral fractures into three main types (Type A, B, C) based on the location of the fracture, which are further subdivided based on bone stock or bone quality (Table 1).

Treatment of periprosthetic fractures Early healing, preservation or reconstitution of bone, restoration of correct alignment, and achieving stable fixation are objectives of treatment. Conservative management by plaster casts or traction devices have become obsolete due to associated complications. Conservative therapy is only recommended, if at all, only for stable fractures of trochanter (Type A fractures), while other types of fractures require operative therapy.8

Periprosthetic femoral fractures after total hip arthroplasty


Table 1. The vancouver classification of periprosthetic femoral fractures6 Type

Location

A

Trochanteric

Subtype A(G): Greater trochanter A(L): Lesser trochanter B(1): Prosthesis stable (18%)

B

About the stem tip

B(2): Prosthesis loose (45%) B(3): Bone stock inadequate (37%)

C

Well below stem tip

â&#x20AC;&#x201C;

Internal fixation Internal fracture osteosyntheses are indicated in cases of unstable Types A, B1 and C fractures, where correct alignment is possible. Varus deviation of the prosthesis or of femur of >6 degrees is a contraindication for internal fixation osteosynthesis due to high rate of pseudoarthrosis; exchange of prosthesis is indicated in such cases. A number of different plate systems are available; however, those used include integrated cable or cerclage devices and modern, less invasive stabilized systems where fixation derives from angular stability of the platescrew interface.9

Strut grafts (SG) Single SG or double SGs are used in cases of stable prostheses (Vancouver Type B1); SGs have an advantage of representing biological osteosynthesis technique. Strut grafts aid restructuring of bone, support healing of fracture and lead to a more stable bone structure. Potential stress riser effect of screw holes is avoided by SGs, and load transmission from distal end of strut graft to normal bone is less abrupt than with plates, which reduces risk of new fracture. The disadvantages of SGs include high cost, limited availability, increased infection, and potential for transmitting disease.10

Revision arthroplasty If the prosthesis is loose (Vancouver Types B2 and B3 fractures) or is fractured, exchange of the prosthesis is necessary. Prosthesis can be replaced either by cemented or cementless stem implant. Cemented stem has a disadvantage of cement being forced into

Perspective

the fracture site and impeding union and healing. Cemented stem is generally recommended only for older patients and for osteoporotic bones, where change to a cementless fixation is difficult.11 Cementless implants Cementless implants are basically of two types; those having their primary point of anchorage at proximal femur and those having it at a more distal point of fixation. The disadvantage of former is that relative motion between proximal fragment of fracture and prosthesis can impede bone ingrowths into the implant. Hence, it is combined with SGs to improve proximal stability. Cementless prostheses with distal fixation (point of fixation lying outside area of fracture) have advantage of allowing the fracture to be bridged. Moreover the fracture gets osteosynthesized, with cerclage wires or cables binding the fracture pieces to the prosthesis. The technique appears to deliver excellent results.9

Treatment based on fracture type Intraoperative fractures Cerclage wires suffice to stabilize longitudinal fractures of proximal femur. Perforations may be managed with cortical strut grafting and use of long-stem implant. Rarely, open reduction and plate fixation may be necessary.

Trochanteric fractures These fractures may be undisplaced or displaced, and undisplaced fractures are treated nonoperatively. However, displaced fractures are treated with tension band wiring if local skin condition and health is favorable. Intertrochanteric fractures are rare and can be treated nonoperatively.12 Intertrochanteric fractures that occur around loose implants should be treated by long-stem revision arthroplasty.

Diaphyseal fractures Femoral shaft fractures are treated according to implant status and bone stock, and operative treatment shows better results than traction treatment.13 Fractures occurring about stable,

Periprosthetic femoral fractures after total hip arthroplasty

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well-aligned stems are repaired with plates. A

Intraoperative fluoroscopy should be considered during instrumentation of the distal femoral shaft to lessen the chance of cortical perforation.

Postoperative fractures are best avoided by performing timely revision surgery.

Proximal osteolytic lesions may be observed in asymptomatic case; however, revision surgery or SG should be done in lesions within 2 cm of stem tip even if asymptomatic.5

combination of unicortical or bicortical screws and cerclage wires are used in case of proximal areas while bicortical screws are used distally. If the distal plate extends to supracondylar region, fixed angle blade plate or dynamic condylar screw offers best fixation.

Fractures distal to femoral stems Fractures occurring below femoral stem are treated without any regard to the implant, if the stem does not show loosening. Nonoperative or internal fixations are used depending on health and activity of patient. In cases of internal fixation, plating is generally preferred.

General principles of management •

Primary considerations in deciding rationale of treatment is whether to treat the fracture operatively or not.

If an operative approach is warranted, whether to proceed with fracture repair or revision arthroplasty.

Conclusion Periprosthetic fractures in THA lead to considerable morbidity in terms of component fixation, bone loss, and subsequent function. Various risk factors have been identified and should be taken into account. Classification of fractures is important for deciding intervention strategy. Early recognition and appropriate management of fractures are critical. Treatment depends on various factors and could be location-specific. Prevention is best and needs attention of the surgeon to minimize periprosthetic femoral fractures.

References 1. Masri BA, Meek RM, Duncan CP. Periprosthetic fractures evaluation and treatment. Clin Orthop Relat Res. 2004;420:80-95.

No single approach is applicable to all cases.

2. Franklin J, Malchau H. Risk factors for periprosthetic femoral fracture Injury. Int. J. Care Injured. 200738,655-60.

Generally speaking, displaced fractures should be stabilized, and loose stems should be replaced with long stems extending well beyond the fracture.

3. Pike J, Davidson D, Garbuz D, et al. Principles of treatment for periprosthetic femoral shaft fractures around well-fixed total hip arthroplasty. J Am Acad Orthop Surg. 2009;17(11):677-88.

Prevention of periprosthetic femoral fractures •

Wide surgical exposure is important as it avoids placing excessive force, especially torque, on the femur. Deficient bone must be identified prior to surgery and efforts made to avoid further bone damage.

Implant removal must be done carefully.

Extended trochanteric osteotomy may be performed to better expose the medullary canal and facilitate cement or prosthesis removal.

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Perspective

4. Schmidt AH, Kyle RF. Periprosthetic fractures of the femur Orthop Clin North Am. 2002;33(1):143-52. 5. Haddad FS, Masri BA, Garbuz DS, et al. The prevention of periprosthetic fractures in total hip and knee arthroplasty. Orthop Clin North Am. 1999;30(2):191-207. 6. Duncan CP, Masri BA. Fractures of the after hip replacement. Instr Course Lect. 1995;44:293-304. 7. Brady OH, Garbuz DS, Masri BA, et al. The reliability and validity of the Vancouver Classification of femoralfractures after hip replacement. J Arthroplasty. 2000;15:59-62. 8. Tsiridis E, Haddad FS, Gie GA. The management of periprosthetic femoral fractures around hip replacements. Injury. 2003:34:95-105. 9. Fink B, Fuerst M, Singer J. Periprosthetic fractures of the femur associated with hip arthroplasty. Arch Orthop Trauma Surg. 2005; 125(7):433-42. 10. Logel KJ, Lachiewicz PF, Schmale GA, et al. Cortical strut allografts for thr treatment of femoral fractures and deficiencies in revision total hip arthroplasty. J South Orthop Assoc. 1999;8:163-72. 11. Kyle RF, Crickard GE III. Periprosthetic fractures associated with total hip arthroplasty. Orthopedics. 1998;21:982-84. 12. Mont MA, Maar DC. Fractures of the ipsilateral femur after hip arthroplasty: A statistical analysis of outcome based on 487 patients. J Arthroplasty. 1994;9:511-19. 13. Beals RK, Tower SS. Periprosthetic fractures of the femur: An analysis of 93 fractures. Clin Orthop.1996;327:238-46.

Periprosthetic femoral fractures after total hip arthroplasty

Bayer surgerie issue 1 dr sanjib k behera  
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