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Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement.
Periprosthetic fracture following TKA occurs most frequently in the femur, primarily in the supracondylar area with an incidence rate of 0.3-2.5%

Knee Periprosthetic Fractures

Femoral Supracondylar periprosthetic fractures are the most common with an incidence rate of 0.3-2.5% post-primary TKR
Periprosthetic fractures of the tibia occur at an incidence of approximately o.4-1.7% in primary TKR and approximately 0.9% in revision TKR

Risk factors for femoral supracondylar fractures include:


  • Anterior femoral notching leading to Supracondylar fracture is a possible yet controversial factor
  • Mismatch of the elastic modulus between the metal implant and the femoral cortex
  • Rotationally constrained components
  • Osteolysis
  • Previous revision TKA has been noted to increase risk from 0.6 to 1.7% (Meek
Patient factors
  • Advanced age most significant factor
  • Osteoporosis
  • Rheumatoid arthritis
  • Female gender  
  • Neurologic disorders incl (epilepsy, parkinsons, poliomyelitis, Myasthenia Gravis
  • DM causes autonomic neuropathy aswell as difficulty with proprioception and hence can predispose to falls and periprosthetic fractures

When a patient first comes to the ED, it is important that the surgeon takes a full history about his or her comorbidities, chronic medications, trauma and whether or not he or she was experiencing pain associated with the joint before fracture occurred. This is vital as it may suggest that there was a pre-existing aseptic loosening of the implant, possibly due to component loosening, polyethylene wear with osteolysis, ligamentous laxity, arthrofibrosis or patellofemoral complications.
Antecedent knee or thigh pain may indicate pre-existing component loosening 
Loosening due to infection needs to be considered in all cases of periprosthetic fracture.
Enquire about a history of pain, swelling, erythema and prolonged wound drainage or a sinus tract following the initial knee arthroplasty. In such a case, then a thorough infectious workup to include serological markers (ESR and CRP) and preoperative joint aspiration with with synovial white cell count (WCC), polymorphonuclear (PMN) cell proportion and microbiological analysis needs to be performed.

A thorough clinical examination involves assessing the patient’s general physical condition. BMI is important as. A large BMI with a large knee is going to pose technical challenges at surgery.Check the state of the surrounding soft tissues and for any neurovascular compromise.

Obtain the old operating notes if possible as this will help with perioperative planning. This is important is you are contemplating using a retrograde nail for fixation

Obtain standard anteroposterior (AP) and lateral radiographs of the knee views.
Typical signs of loosening will appear as displacement of the femoral component or stem with a complete radiolucent line of 2 mm or more around the prosthesis at the bone–cement interface. In more complex cases, where the fracture pattern cannot be completely identified with AP and lateral X-rays, a CT-scan may aid in the detection of loosening or to gain a clear picture of the fracture pattern. If previous radiographs are available, they should be analysed for comparison

Supracondylar Femoral Periprosthetic Classification System

1 Non-displaced and prosthesis intact
2 Displaced fracture and prostesis intact
3 A non-displaced or displaced fracture with a loose prosthesi

Type 1:

Most common and can be asymptomatic and discovered on routine follow-up radiographs. These fractures present with a well-fixed implant and an intact extensor mechanism

Type 2:

Associated with difficulty in knee extension but retains a well-fixed implant. This type is associated with a high rate of complications (50%) and recurrent operations (42%)

Type 3:

Associated with loose patellar implant and subdivided into:

    3a – implemented if there is a good remaining bone stock

    3b – implemented if the remaining bone stock is of poor quality

Tibial Plateau Periprosthetic Classification System

Type Fracture of tibial plateau
I Fracture adjacent to tibial stem
II Distal to component 
III Fracture of tibial tubercle 

 THA incidence is increasing due to developments in the field of joint replacement, which is leading to increased numbers of arthroplasty procedures in the elderly population

Periprosthetic fractures can be divided into two categories
     – Intraoperative and Postoperative fractures.
Each has its own Vancouver Classification and treatment recommendations.

Intra-operative Fractures

  • 3.5% of Primary Uncemented Hip Replacements
  • 0.4% of cemented Arthroplasties

Post-operative Fractures

  • 0.1%
  • Stem tip most frequent
Type Description Treatment
 A1   Proximal metaphysis, cortical perforation Bone graft alone (e.g acetabular reaming)     
 A2   Proximal Metaphysis, Non-displaced crack

Cerclage  wire before inserting stem(prevents crack propagation)

Ignore the fracture if fully porous coated stem is used-ONLY if there no distal propagation

 A3   Proximal Metaphysis, displaced unstable fracture

Fully porous coated stem,or tapered fluted stem provided 

Wires/Cables/Claw plate for isolated GT fractures

 B1   Diaphyseal, cortical perforation (usually during cement removal) Fully porous coated stem(bypass by 2 cortical diameters)
 B2   Diaphyseal, non-displaced crack (from increased hoop stress during broaching or implant placement)

Cerculage wire(if implant stable

Fully porous coated stem to bypass defect(if implant unstable +/- Strut Allograft

PWB and observation (if detected postop)

 B3   Diaphyseal, displaced unstable fracture ( usually during hip dislocation, cement removal, stem insertion) Fully porous coated stem to bypass defect +/- strut allograft
 C1   Distal to stem tip, cortical perforation (during cement removal) Morcelised bone graft, fully porous coated stem to bypass defect, strut allograft
 C2   Distal to stem tip, cortical perforation (during cement removal) Morcellised bone graft, fully porous coated stem to bypass defect, strut allograft
 C3   Distal to stem tip, displaced unstable fracture ORIF
Table 1:Vancouver Classification - Intraoperative Femoral Fractures

Intraoperative Acetabular Fractures
Greater incidence in cementless acetabular insertion (0.4%) compared with (0.2%) in cemented. It is often at the point of acetabular component impaction.

Risk Factors
Cup Under-Reaming
Elliptical Nodular Cups
Previous Radiotherapy


  • If identified intraoperatively and the cup was deemed to be stable the patient can be advised to be partial weight bearing 8 weeks

Acetabular Revision

  • Acetabular screws can be inserted to stabilise the cup
  • ORIF: If the posterior column of the cup is unstable ORIF and revision is the most appropriate management
  • Bone graft in the case of poor bone quality
  • Partial weight bearing for 8 weeks

Intraoperative Femur Fracture

Primary THA: 0.1-5%
Revision THA: 3-21%
Proximal Fracture:
     -Bone preparation due to excessive rasping
     -Prosthetic insertion (incorrect implant size)
Mid Femur Fracture:
      -Excessive force during surgical exposure
Distal Femur Fracture:
      -Straight stem prosthesis impacting at femoral bow

Risk Factors
Revision Arthroplasty
Female sex
Surgical Error
Cementless implants

Post Operative Femur Fracture

0.1-3% for primary cementless total hip arthroplasties

Early postoperative fractures
Cementless insert fracture 3-6 months post op.
Stress risers during reaming and broaching are thought to be causative
wedge-fit tapered designs cause proximal fractures
cylindrical fully porous-coated stems can result in distal split in femoral shaft

Late postoperative fractures
Cemented prosthesis are more prone to fracturing after 5 years.
They fracture around the tip of the prosthesis or distal to it.

Risk factors
Inferior bone quality
Cementless prostheses
Compromised bone stock
Patient who have underwent a revision procedure.





Fracture in trochanteric region

Commonly associated  with osteolysis,

AG (Greater trochanter) fractures caused by retraction, broaching, actual implant insertion, previous hip screws

Firstly treat the osteolysis

AG fractures with <2cm displacement, treat nonoperatively with partial WB and allow fibroud union

AG fractures >2cm needs: ORIF (loss of abductor function leads to instability) with trochanteric claw/cables

B1 Fractures around stem or just below it, with a well fixed stem

ORIF using cerclage cables and locking plates

B2 Fracture around stem or just below it, with a loose stem but good proximal bone stock

Revision of the femoral component to a long porous-coated cementless stems and fixation of the fracture fragment

Revision of the acetabular component if indicated

B3 Fracture around stem or just below, with proximal bone that is poor quality or severely comminuted Femoral component revision with proximal femoral allograft or proximal femoral replacement
C Fracture occurs well below the prosthesis  ORIF with plate: Leave the hip and Acetabular prothesis alone


Case based Discussion Periprosthetic knee fracture


A 72-year-old lady presents to ED following a fall on pavement. She complains of pain around the right knee arthroplasty performed 7 years previously. She did not have any knee discomfort or symptoms prior to the fall.  She is independent with activities; medical comorbidities include Type 2 Diabetes Mellitus and ischemic heart disease.Her radiographs are shown below (Figure 1)

Periprosthetic knee .png

Figure 1.Anteroposterior(AP) and lateral radiographs right knee 

Question 1:How: would you describe this injury on the radiographs?

Question 2:What  are the likely treatment options you would discuss with patient?

Answer:This is a periprosthetic distal femur fracture around a stable cruciate retaining knee replacement. This can be classified as Type B1 in Unified Classification System (UCS) for periprosthetic fractures. Type B1 and C fractures are usually managed with fixation of the fracture, which can be with a plate or intramedullary nail. Retrograde nailing is a reasonable option when there is adequate distal bone stock to allow a hold with interlocking screws; but this is only possible with cruciate retaining or open box cruciate sacrificing knee replacement. Assessment of the proximal femur and hip is essential for planning the fixation.

Distal femoral replacement is recommended for Type B2 and B3 fractures. This is increasingly popular management option due to the advantage of early mobilisation although this is a complex procedure with associated risks. There are studies looking at the overall cost benefit with a distal femoral replacement due to the less number of days in hospital and earlier return to activity.

The patient was counselled about different treatment options and elected to have fracture fixation with a distal femoral locking plate. She was progressing well at 3 months follow up visit, walking using a single crutch.

Further reading:
Duncan CP, Haddad FS. The Unified Classification System (UCS): improving our understanding of periprosthetic fractures. Bone Joint J. 2014 Jun;96-B (6):713-6.
Darrith B, Bohl DD, Karadsheh MS, Sporer SM, Berger RA, Levine BR Periprosthetic Fractures of the Distal Femur: Is Open Reduction and Internal Fixation or Distal Femoral Replacement Superior?. J Arthroplasty. 2019 Dec 20. pii: S0883-5403(19)31182-9. 

She presents 6 months later with sudden increase in pain around the right knee. She has recently increased her activity level with outdoor walking and exercises. Radiographs show breakage of distal screws and secondary displacement of the fracture(Fgure 2). 

Question 3:What are the causes of fixation failure? 

Question 4:How would you manage the current situation?

Periprosthetic knee 2.png

Figure 2.Anteroposterior(AP) and lateral radiographs right knee

Answer:The sudden increase in pain around the right knee is due to failure of fracture union leading to fatigue failure of screws. It is important to exclude infection as a cause of fixation failure.This patient subsequently underwent distal femoral replacement after counselling of the various available treatment options(Figure 3 ).

Periprosthetic knee 3 .png

Figure 3.Anteroposterior(AP) and lateral radiographs right knee DFR.

Question: How would you plan to perform the distal femoral replacement for a failed internal fixation?

Answer:This is essentially two operations, metal work removal and distal femoral replacement (DFR)

A high thigh tourniquet may be applied if there is adequate clearance from the surgical field. Surgical approach is the next consideration, as it needs to allow access for removal of plate and screws. It can be performed through a midline knee incision with extension as a lateral subvastus approach or separate lateral incision for removal of plate. The level of bone resection around the distal femur would be dictated by level of fracture, bone quality and available length of prosthesis segment. Restoration of joint line and component rotation can be achieved by marking on the bone before bone resection and trial assessment. In this case, the proximal screws were still intact and taken out with ease. Broken proximal screws are less common but can be an issue as they come in the way of a femoral stem. Intraoperative fluoroscopy is useful to check whether the stem of a DFR has adequately bypassed the screw holes to avoid a stress riser. It is good practice to have adequate bone contact to the hydroxyapatite collar if the DFR prosthesis being used has one. Vigilance for postoperative wound closure and healing is vital as infection and extensor mechanism problems are challenging concerns.

Further reading:
Haidukewych GJ. Role of Distal Femoral Replacement for Periprosthetic Fractures Above a Total Knee Arthroplasty: When and How? J Orthop Trauma. 2019 Sep;33 Suppl 6: S33-S35.



A 71-year-old fit and well male sustains a fracture of his femur between a hip and knee replacement. The fracture is in the supracondylar area, 3cm above the superior aspect of the knee replacement. The fixation of either hip or knee replacement is not involved. You are planning the fixation and need to decide which modality of treatment will give you best fixation for early weight bearing and decrease future complications.
Which treatment strategy will you choose?


1. A. Combined retrograde nail from the knee to the tip of the hip replacement with a locking plate to the tip of the hip replacement
2. B. Combined retrograde nail from the knee to the tip of the hip replacement with a locking plate to the proximal femur with screws around the femoral stem of the hip replacement
3. C. Locking plate fixation from the distal femur to the proximal femur with screws around the femoral stem of the hip replacement
4. D. Locking plate fixation from the distal femur to the tip of the hip replacement
5. E. Retrograde nail from the knee reaching close to the tip of the hip replacement.


PC: A 70 year old man presents to the ED after being knocked off his bike by a car. He is complaining of significant pain over his left thigh and hip.

PMHx: Left total hip arthroplasty, HTN, high cholesterol. 

O/E: Erythema and swelling over right proximal thigh, reduced range of movement in the right hip.

Initial plain film radiograph left femur.  

After reviewing the radiograph you note a periprosthetic fracture(Figure  1)

 Vancouver 3C.png

Figure 1.Radiograph left proximal  femur

What is the Vancouver classification and optimal managment option?


1. Vancouver AG, ORIF
2. Vancouver B1, ORIF with impaction grafting
3. Vancouver B2, ORIF with femoral strut allograft augmentation
4. Vancouver B3, revision to proximal femoral replacement.
5. Vancouver C, revision to proximal femoral replacement


  • 1. Periprosthetic fractures of the knee: a comprehensive review. Vadim Benkovich1 · Yuri Klassov2 · Boris Mazilis3 · Shlomo Bloom2.
  • 2. Meek RMD, Norwood T, Smith R, Brenkel IJ, Howie CR (2011) The risk of peri-prosthetic fracture after primary and revision total hip and knee replacement. J Bone Jt Surg (Br) 93:96–101
  • 3. Felix NA, Stuart MJ, Hanssen AD (1997) Periprosthetic fractures of the tibia associated with total knee arthroplasty. Clin Orthop Relat Res.