patellar fracture 1

8/12/2019 Patellar Fracture 1

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Patellar Fracture

Dr Mohd Syafiq Bin Shahbudin

MB BCh (Alex)



Introduction

Patella is a thick, circular-triangular bone which

articulates with the femur (thigh bone) and

covers and protects the anterior articular

surface of the knee joint



Anterior surface

Posterior surface

Course ,flattened

and rough.

(For quadriceps

tendon attachment)

Distal apex

Origin of patella

ligament

Medial

facet

Lateral facet

Numerous

vascularcanaliculi

Vascular canaliculi

filled by fatty tissue



Incidence

• 1% of all fractures

• common: 20 to 50 years old.

• Men > women



Type of patella fracture

• Non displaced

- Tranverse

- Stellate

- Vertical

•Displaced-Tranverse

-Stellate-Multifragmented

-Polar

-Proximal

-Distal

-Osteochondral



Non Displaced fracture

Transverse pattern (50 – 80% of cases)

• 80% occur -> middle to lower 3rd of patella

• >35% injuries are non displaced

• Usually minimal damage -> extensormechanism remains intact.



• Stellate fracture

- From a direct compressive blow

- Account 30% - 35% of patella fracture

- > 50% of these fracture are nondisplaced

- Due to it injury mechanism, damage to

femoral and patellar articular surfaces can

occur



• Longitudinal / marginal vertical

- 12 to 17% of patella fractures

- Marginal -> from direct trauma and involve

lateral facet

- The fracture not seen in standard x-ray view.

axial views are necessary



Displaced fracture

Fracture fragment separation more than 3mmor an articular incongruity of 2mm or more.

Extensor mechanism disruption with displaced

fracture -> indication for operative repair



• 52% displaced tranverse -> non comminuted

• Some patient may demonstrate displaced

fracture fragments but maintain active

extension of the leg



Comminuted fracture

Unstable fracture.

The bone shatters into pieces



Open fracture

The skin has been broken and exposes the bone.

Involve much more damage to the surrounding

muscles, tendons, and ligaments.

Higher risk of complication and late healing.



Cause

• Patellar fractures are most commonly caused

by a direct blow.

• The patella can also be fractured indirectly.

Eg: Quadriceps muscle is contracting but the

knee joint is straightening.(Eccentric contraction)



Investigations

• History taking

• c/o by the patient

•

Test: Straight leg raise test

- To test the function of the the quadriceps

muscle and its attachment to tibia.- Disruption of quadriceps, patella tendon or

patella itself lead to inability to perform test.



• X-ray

- Differentiate other abnormalities such as

bipartite patella.



Bipartite patella

- A congenital fragmentation or synchondrosis

of the patella as the result of developmentallack of assimilation of the bone during growth.

- Occurs in approximately 1 % of population.

Characteristic x-ray

features:

- Rounded

- Sclerotic lines ratherthan the sharp edges of

a fracture.



Treatment

• Non surgical treatment –

Indications:

- For undisplaced fractures with intact articular surface.- Preserved extensor mechanism with maintained active

extension against gravity.

- Retinacula on either side of patella should not be torn.

- There should be minimal displacement of fragments (2-3mm)

- Minimal disruption of the articular surface (2-3mm)

- Tranverse undisplaced fracture of the patella is anavulsion fracture

- Should aspirate with occurrence of tense hemoarthrosis.



Management:

• Intact extensor function:

-knee immobilizer, rest, ice, analgesia

• Diminished extensor function:

- Immobilize, rest, ice, analgesia, Non weight

bearing and proceed with ORIF



• Surgical treatment –

Indications:

- Extensor mechanism involvement

- Displaced transverse fracture, either simple or comminuted,with associated disruption of quadriceps retinacula.

- Patella fractures with compromised overlying skin shouldundergo delayed fixation.

Disruption of

quadriceps

retinacula



Cerclage wiring

Indicated in:

- Displaced fracture

- Impaired extensor function.

• Cerclage wiring may be used alone or

combination with lag screw.



• cerclage wire plaster/ thermoplastic/

cylinder treatment of the leg/ removablesplintage as support

Contraindication:• Polytrauma patient in extremis

• Medically unfit for surgery

• Local soft-tissue compromise



Advantages

•Restoration of extensor function

•Early mobilization of knee joint

•No plaster, or prolonged splintage

Disadvantages

•Caution with knee mobilization is needed, if asingle cerclage wire is used

•Secondary displacement

•Prominent metalwork after fixation•articular malunion

•Risks of open operation



Tension band wiring

• Commonly indicated in transverse displaced

patella fracture and also comminuted fracture

of patella.



Technique:

- Reduction of fracture with reduction of clamp

- K-wire is inserted perpendicular to the

fracture- Figure of 8 tension band wire is applied for

compression of the fracture



• These tension band wires convert anterior

distractive forces to compressive forces at the

articular surface

• (More flexion of the knee will give more

compression to the articular surface)



Wound Closure:

- Following implant insertion, the extensor

retinaculum is repaired

- The superficial retinaculum must be closed

properly in order to maximize coverage over

the implant.



• Post Operative Care:

- Patient is immobilized for 2-3 weeks

- begin prone hang exercises at 2-3 weeks

- crutches are discontinued after 6 weeks



Claw plate



Patellectomy

Partial Patellectomy

Involve distal pole of patella



• Smaller fragments are excised

• The patella tendon is reattached anteriorly

with sutures



• Complications: Suture pull out.

Signs:

- Look for proximal migration of upper patellar

pole on radiography or by absence of palpable

quad tendon repair to inferior pole fragment

- Absence or weakness of quadriceps function

- Inability to palpate the patellar ligament or

detection of gap between ligament and pole.



Total Patellectomy

Total patellectomy is reserved for severe

multifragmentary fractures (comminuted and

displaced) of the patella, which may be

combined with significant osteochondral

damage to the patellofemoral joint



• Bone fragments are excise before

reattachment to patella tendon



Complication of patella fracture

• Infection

• Loss of reduction

• Failure of internal fixation

• Malunion

• Quadriceps weakness

•Extensor lag

• Traumatic arthritis of patellofemoral joint

patellar fracture 1

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