PERIPROSTHETIC FRACTURESMehdi Abbasi M.D

Shariati hospital

P.P.F increases in frequency

P.P.F often increase in osteoporotic bone, making stable fixation even more problematic

Mechanisms of injuryLow-energy falls are the mechanisms of

injury in most patientsAccording to last Swedish registry at least

75% of P.P.F occur postoerativelySpontaneous P.P.F is more common after

revision surgeryHigh energy trauma accounts for only a small

percentage of P.P.F and these types are associated with a more comminution

Mechanisms of injuryIntraoperative P.P.F occur more commonly

during revision proceduresGiven the predominance of low-energy injury

mechanisms, associated injuries are uncommon

HistoryHistory should include:

Date of implantationUsed prosthesisArthroplasty complication such as infectionFunctional state of patient, any recent changes

in status or symptoms related to the arthroplasty can be a clue to heighten suspicion of subtle P.P.F or prefracture implant loosening

Physical examPrior surgical wound

Presence or absence of associated lesions

ImagingA.P and lateral views of joint and full length

of bones above and below the jointAttention should paid to fractures ,

prosthesis(loosening), osteolysis, cortical erosion cortical penetration and notching

Diagnosis of intraoperative fractures can be from direct observation, but intraoperative radiograph should be obtained

Incidence and risk factor300000 T.K.A per year0.3% to 2.5% P.P.F in primary T.K.AUp to 38% P.P.F in revision T.K.APatient-specific risk factors:

R.AOsteolysisOsteopenic boneFrequent fallsTechnique-specific risk factors

Incidence and risk factorsOsteopenia is a major contributing factor of

P.P.F B.M.D in the distal of femur decrease 19-44%

one year after T.K.AStress fracture in the femur and tibia have been

described after T.K.A . The patient complains of sudden pain without trauma and sign of infection

Periodic X.R and early bone scan are diagnosticLocal factors : osteolytic lesion, anterior femoral

notchingP.S femoral component increases risk for

intraoperative fracture

Classification of P.P femur fractureLewis and rorabek classification

Classification of P.P femur fractureSu et al classification

treatmentNonoperative treatment for displaced

fractures has been associated with poor results.

Internal fixation: traditional condylar buttress type plate is

prone to complicationTraditional fixed angle plate constructs such as

condylar plate reduces varus collapse but have limited application.

Modern methods of fixation, locked plating and retrograde nailing, provide superior results

treatmentBicondylar and unicondylar locked screw

fixation provide excellent distal fixation.

Retrograde intramedulary nailing can be applied to P.P.F

that have adequate distal bone stock. It is preferred method by some authors.

Revision knee arthroplastyFor patient with loose implant associated with a P.P.F

or inadequate bone stock to achieve fixation, revision is considered

In patient with a loose implant or a history of prefracture pain, occult infection should be ruled out.

Revision T.K.A with intramedulary femoral stem that engage the diaphysis and simultaneously stabilize the fracture can be used

Distal femoral replacement megaprosthesis have been used for salvage of failed internal fixation of P.P.F

For a younger, active patient an allograft prosthetic composite may be a better alternative

Periprosthetic fracture of tibial and patellaIncidence:

They are less common than femoral side

According to myoclinic joint registry (1999) incidence of P.P.F after primary T.K.A is 0.4% in the tibia 0.7% in the patella and 0.9% in the femur

The frequency of P.P.F in revision surgery is higher

PatellaPatellar fracture is the second most frequent

P.P.F around the knee.About 12% of reported fractures were

directly associated with trauma. The remaining occurred spontaneously and most fractures occur during first 2 years after arthroplasty .

Etiologic factors specific to the patella are component design, excessive resection of bone , limb and prosthesis alignment and lateral release .

Classification of patellar fractures

Classification Type I Type II Type IIIa Type IIIb

Extensor mechanism Intact Disrupted Intact Intact

Implant fixation Well-fixed Well-fixed or

loose Loose Loose

Bone stock Unspecified Unspecified Reasonable Poor

Classification of Tibial fractures

Classification Type I Type II Type III Type IV

Fracture location Tibial plateau Adjacent to

stemDistal to

prosthesisTibial

tubercle

Subtype

A Prosthesis well-fixed

Prosthesis well-fixed

Prosthesis well-fixed

Prosthesis well-fixed

B Prosthesis loose

Prosthesis loose

Prosthesis loose

Prosthesis loose

C Intraoperative

Intraoperative

Intraoperative

Intraoperative

Patellar fracture treatmentPatellar fracture treatment: no operative – ORIF –

component resection patellectomy .When extensor mechanism is intact , conservative

management is recommended .Surgical management is reserved for disturbance of

extensor mechanism integrity , a loose patellar component and patellar maltracking .

ORIF with T.BW or cerclage wiring results in nonunion with an average nonunion rate of 82%

Therefore operative management is not an unreasonable consideration even in the face of a disrupted extensor mechanism.

Patellar fracture treatmentThe presence of fracture and a loose implant

is associated with high complication rates regardless of treatment method.

When there is adequate bone stock (>10mm) revision of the patellar component is reasonable.

Severe bone loss mandates patellar resection arthroplasty .

Extensor lag about 10˚ and a limitation of 20˚-30˚ of flexion are common.

TIBIA

P.P.F of tibia are uncommonMost often they are associated a loose tibial

component therefore revision is preferred in these situations.

Tibial revision for P.P.F requires the routine use of stem end augment and metaphysical filling metal implants.

The surgeon should be aware that isolated tibial component revision is rare, and commonly, should be prepared to revise the entire arthroplasty.

When arthroplasty component is stable , locked plate is preferred method of treatment.