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.
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