ottawa clinical decision rule - a prospective, validation study for use of radiography in acute...

Ottawa Clinical Decision Rule - A Prospective, Validation Study for use of Radiography in Acute Ankle, Mid Foot and

Knee Injuries in the ED, South India.

SRMC&RI

Dr. Srihari. Cattamanchi., M.D. (A&EM).Sri Ramachandra Medical College & Research Institute,

Chennai . India

Background

• The Ottawa clinical decision rules are a set of

guidelines for doctors to aid them in deciding if a

patient with ankle, foot or knee pain should be offered

x-rays to diagnose a possible bone fractures.

• Before the introduction of the rules most patients with

ankle, foot or knee injuries would have been x-rayed.

Background

• However only about 15% of X-rays were

positive for fracture, other patients had sprains

or other injuries.

• As a result many unnecessary X-rays were

taken, which was costly, time consuming and a

possible health risk.

Ottawa rules for x-ray of ankle

An ankle x-ray is required only if there is any pain in

Malleolar zone and any of these findings:

– age 55 or over

– bone tenderness at posterior edge or tip of lateral

malleolus

– bone tenderness at posterior edge or tip of medial

malleolus

– inability to weight bear both immediately and in ED

Ottawa rules for x-ray of ankle & Foot

Ottawa rules for x-ray of foot

A foot x-ray is required if there is any pain in the

Midfoot zone and any of these findings:

– age 55 or over

– bone tenderness at Base of 5th Metatarsal

– bone tenderness at Navicular

– inability to weight bear both immediately and in the

emergency department.

Ottawa rules for x-ray of ankle & Foot

Ottawa rules for x-ray of knee

A knee x-ray is only required for knee injury patients with any of these findings:

– age 55 or over

– isolated tenderness of the patella

– tenderness at the head of the fibula

– inability to flex to 90 degrees

– inability to weight bear both immediately and in the emergency department.

Objectives

To determine the sensitivity and specificity of the

Ottawa clinical decision rules.

To determine whether use of the rule would reduce the

number of radiographs ordered.

Materials & Methods

Design: A prospective, analytical, validation study

Setting: Done at an academic ED of Sri Ramachandra

Medical College & Research Institute, a tertiary care

university hospital, & Level I trauma center, in South

India.

Duration: Between June 1st 2008 and December 31st

2009.

Materials & Methods

Inclusion Criteria:

– All patients registered in the ED,

– above 2 years of age,

– sustained Ankle, Foot or Knee injury in

preceding 7 days, and

– evidence of bony injury on physical

examination.

Materials & Methods

Exclusion Criteria:

– Paraplegic patients,

– pregnant,

– altered sensorium,

– polytrauma or

– other major fractures.

Sampling: A consecutive sampling technique .

Statistical analysis: Sensitivity, specificity & 95%

confidence interval done with SPSS Ver.17.0

Instrument: A preformatted proforma was used.

Materials & Methods

Results – Age & Sex Distribution

0

50

100

150

200

250

1 - 10Years

11 - 20Years

21 - 30Years

31 - 40Years

41 - 50Years

51 - 60Years

61 - 70Years

71 - 80Years

> 80Years

No

of

Pat

ien

ts Male - 671

Female - 258

Mechanism of Injury

277

201

451

Direct Blow

Torsion

Other indirectinjury

Causes of Injury

74

224

502

17112

Sports Injury

Fall Related Injury

Road TrafficAccidents

Assault

IndustrialAccidents

Injuries Sustained

205

325

399 Ankle

Foot

Knee

History

239

43

690

656

0 100 200 300 400 500 600 700 800

Cracking / Popping Sound Heard

Lower Limb Injury in Precedingyear

Able to Bear weightImmediately

Able to continue activity beingperformed at time of Injury

Range of Motion

612

317

Full

Restricted

Ability to Bear Weight – 4 Steps in ED

690

239

Yes

No

Bone Tenderness of Ankle Joint

1316

4

97

13

0

2

4

6

8

10

12

14

16

18

Lateral Malleolus Medial Malleolus

No

of

Pat

ien

ts

Anterior Edge Inferior Tip Posterior Edge

Bone Tenderness of Foot

21

57

24

Fig. 13. Bone Tenderness of the Foot

Cuboid Navicular Base of Fifth Metatarsal

Bone Tenderness of Knee Joint

22

36 39 4455

33

60

43

0

10

20

30

40

50

60

70

Patella IsolatedPatella

Patella &DirectBelow

MedialFemoralCondyle

LateralFemoralCondyle

Medial TibiaLateral Tibia TibialTuberosity

No

of

Pat

ien

ts

Prospective Prediction of Ottawa Clinical Decision Rule

87113

81118

212

318

0

50

100

150

200

250

300

350

Ankle Foot Knee

No

of

Pat

ien

ts

Fracture No Fracture

Radiographs Ordered

632

769

1224

Ankle

Foot

Knee

N = 2625

Fracture Yield

• Fractures Detected

• 69 ankle fractures,

• 104 midfoot fractures and

• 66 knee fractures.

• Fracture Yield

• 10.9% for ankle films,

• 13.5% for foot films and

• 5.4% for knee films.

Radiological Findings

136

221

333

69104

66

0

50

100

150

200

250

300

350

Ankle Foot Knee

No

of

Pat

ien

ts

Normal Study Signigicant Fracture

Missed Fractures

Rule failed to predict fracture in 3 ankle injuries

and 2 midfoot injuries

Two were distal fibula fractures and one was

distal tibia fracture.

Two missed midfoot fractures were of 5th

metatarsal and calcaneus.

The examiner’s clinical impression was no

fracture.

Disposition

333

487

2881

Discharged Admitted to Ward Admitted to ICU / Immediate Surgery DAMA

Sensitivity, Specificity & Negative predictive

value of rule in ankle, foot & knee injuries.

Parameters1 Ankle Foot Knee

Sensitivity 95.6% 98% 100%

Specificity 86.7% 95.5% 95.7%

Negative Predictive

value

97.5% 99% 100%

Positive Predictive

Value

78.5% 91.8% 82.5%

Potential Radiographic

Savings

57.5% 65.2% 79.6%

Limitations

Study population - convenience sample of eligible

patients.

May have introduced selection bias toward patients with

more severe injury.

This is suggested by our relatively high fracture yields for

ankle and mid-foot injuries.

Examination accuracy may have varied among

examiners.

Inter-rater reliability not assessed.

Conclusion

Prospective validation has shown Ottawa Rules to be

100% sensitive for identifying fractures of knee.

However, their sensitivity is not 100% in ankle and foot

injuries.

Appears to be much more sensitive than clinical

impression

Conclusion

May be used as a guideline for selectively ordering

radiographs in acute ankle, foot and knee injury.

Application of the rule would have led to a 32% relative

reduction in use of radiography in the ED.

This would inturn decrease waiting times for patients

discharged without radiography by 55 minutes in this

study.

Thank You

My friends & Colleagues

My friends & Colleagues