Patella Fracture

Mechanism

 

Direct blow

- most common

 

Indirect

- forced knee flexion with foot fixed / maximally contracted quadriceps

 

Types

 

1.  Vertical

 

Patella Fracture Vertical

 

2.  Transverse

 

Patella Fracture DisplacedPatella Fracture Displaced AP

 

3.  Burst / Stellate

 

Patella Fracture Stellate

 

Management

 

Non operative

 

Indications

 

Vertical

- biomechanically stable

 

Undisplaced transverse fractures

- < 2mm

- extensor mechanism intact

- able to straight leg raise

 

Patella Fracture TransverseUndisplaced patella fracture

 

Operative

 

Indications

 

Displaced transverse fractures

 

Techniques

 

1.  TBW

 

Patella TBW LateralPatella TBW AP

 

2.  Cerclage wire +/- ORIF

- stellate fractures

 

3.  Lag screws

 

4.  Patellectomy

 

Technique

 

Concept

 

Excise patella in full close retinaculum tightly with VMO advancement

 

Concerns

- extensor lag and weakness

- continued pain if trochlea lesions

- issues with later TKA

 

AO Surgery Reference Technique



Surgical technique PDF

 

Results

 

Outcomes

 

Baker et al JBJS 1988

- patellectomy for OA in 20 knees

- 19/20 satisfied

 

Cavaignac et al KSSTA 2014

- systematic review of 31 articles and 1400 patellectomies

- 85% good or excellent if extensor mechanism reinforcement is performed

 

Complications

 

Ziran et al CORR 1994

- 12 patellectomies

- good function, but extensor weakness and ROM differences



Asopa et al J Orthop Surg Res 2015

- better results with disease confined to the patella

 

TKA and patellectomy

 

Asadollahi et al Knee 2017

- systematic review of TKA after previous patellectomy

- reduced flexion and increased risk complications in patients with patellectomy

 

Indications

- unreconstructable fracture

 

Risks

- extension lag / weakness

- anterior instability

 

Gunal et al JBJS Br 1996

- patients with at least 5 fragments

- advocated VMO advancement

- additional medial parapatellar incision

- advance laterally and distally

- demonstrated improved strength and decreased lag

 

Patellectomy Lateral

 

Late Management

 

Malunion Patella Fractures

 

Partial patellectomy

- remove part of medial or lateral facet

- good functional and pain relief

 

Non Union Patella Fragment

 

Patella Fracture nonunionPatella Fracture NonunionPatella Fracture Nonunion CT

 

Patella Fracture Nonunion