OCS Exam Webinar Review #1. Ground Rules

Transcription

1 Presents OCS Exam Webinar Review #1 Developed & Presented By: Eric Wilson, PT, DSc, DPT Board CerAfied, Orthopedic Physical Therapy Board CerAfied, Sports Physical Therapy CerAfied, ElectrodiagnosAc TesAng CerAfied Strength & CondiAoning Specialist NASM- Performance Enhancement Specialist Fellow American Academy of Orthopedic Manual Physical Therapists Ground Rules Type quesaons I ll try to answer all before leaving the secaon All other quesaons please wait and type them at the end. We will have plenty of Ame for quesaons 1

2 OBJECTIVES Upon compleaon of this course the paracipant will be able to: Understand research and staasacs as it pertains to successfully passing the OCS Exam Describe the Clinical PredicAon Rules for radiology of the cervical spine, knee, ankle and foot Prometrics TesAng Center 2

3 AGENDA (tentaave) 8:00pm: Research & StaAsAcs 8:45pm: CPRs for imaging 9:30pm: QuesAons 10:00pm Post- Test/Course Complete 3

4 Research & StaAsAcs A Brief Review of Commonly Asked QuesAons 3 Components of Evidence Based Medicine (EBM) 1. Individual clinical experience 2. PaAent preferences 3. Best available external evidence from systemaac research and consideraaon of available resources 8 4

5 Guidelines: Strength of Evidence 9 Guidelines: Strength of Evidence 10 5

6 Based on Validity of Study 6

7 From: Center for Evidence- Based Management 7

8 Prevalence vs. Incidence Prevalence: the proporaon of a populaaon with a problem at a designated Ame Studies with likelihood raaos and Pre- Test Probability Pre- Test Probability = Prevalence 15 of 50 subjects had the condiaon of interest during the research study Prevalence/Pre- Test Probability = 30% Incidence: rate of a new problem during a period of Ame Power The probability that the test will reject the null hypothesis when the research hypothesis is true (i.e. not commigng a Type 2 Error) 8

9 Errors Type 1 Error (Home): Backing a LOSER Type 2 Error (Guest): Missing a WINNER Confidence Intervals (CI s) Provide the reliability of an esamate Means are esamates of true values what we think the populaaon at large looks like based on our sample CI s tell us how accurately the Mean represents the populaaon Typically expressed as 95% CI Probability that the populaaon falls within the two limits 95% CI vs. 95% CI Like all esamates, the narrower the bejer 18 9

10 CI s: An AutomoAve Example $250- $1,000 $450- $ Confidence Intervals Cook (2010) Unlike p- values, CI s are easier to interpret regarding the precision of an esamate A low p- value does not necessarily = high level of precision CI s moves researchers away from accept/reject dichotomy of p- values Indicates how good an esamate is by providing a range of uncertainty for the esamate CI vs. p- value: a finding may have a low p- value (good) but a wide CI (bad) suggesang low precision and wide variance in potenaal results 20 10

11 CI Summary Help us to extrapolate results from a study to our paaents If CI crosses zero (range includes posiave and negaave values) the results cannot be considered staasacally significant (Fejers & Tilson) 21 Clinical Significance: Effect Size Results may be staasacally significant but that does not mean they are clinically significant To be considered clinically significant, results must Show change on a measure that has value to the paaent (paaent expectaaons/values) Show a change of a magnitude that will make an actual difference in the paaent s life (funcaon, etc) 23 Fejers L, Tilson J. Evidence Based Physical Therapy. 2nd ed. F.A. Davis;

12 Effect Size: How Calculated Can be calculated for all forms of measures The measure of standardized mean difference (Cohen s d) between two comparaave groups that measure conanuous data is the most common (Cook 2008) Outcome variable dictates whether effect size (+) or (- ) ODI, NPRS: lower score=bejer outcome Exp Grp improves > Control Grp = (- ) Effect Size If not included in paper, calculate on your own 24 Cook, 2008 Effect Size: How Used Allows greater precision in determining true magnitude of the intervenaons when results are not Large or obvious or staasacally significant Unlike p- values, are independent of sample size Useful when evaluaang over/under- powered studies manual therapy studies oren suffer from small sample sizes 25 Cook,

13 Effect Size: How Used Meta- Analysis Summarize findings from different studies and allow pooling of data Differences in effect size are typically reflecave of study bias or design variaaon more so than disparity in intervenaon outcome VariaAons include control groups, types of care provided, outcome measures and providers 26 Cook, 2008 Effect Size Guidelines 27 Cook,

14 Group A Group B Example Effect size 0.9 = 82% of control group below the average score in the experimental group Mean Scores 28 Effect Size: LimitaAons May provide misleading findings, especially when Biased study design Data is not normally distributed SD s are very wide 29 14

15 Effect Size: Summary Tells us if the results of the study are important Ability to translate a paaent s change in health status to a standardized value (effect size) Actually correlates to GROC scores Middel, J Eval Clin Pract, Cook, 2008 InterpreAng LRs From Fritz

16 Nomogram Easily converts pre- test probabiliaes into post- test probabiliaes for diagnosac test results with a known Likelihood RaAo 32 Laslej s CPR SIJ Pre- Test: 26% At least 3 posiave Pain ProvocaAons Tests +LR: 4.16 Post- Test: 59% <3 posiave Pain Prov tests - LR 0.12 Post- Test: 4% Laslej, Man Ther,

17 Cervical Spine Knee Foot/Ankle Radiology Rules 35 17

18 Ojawa Cervical Spine CPR Level II Predictors (3 series) 1. Any high- risk factors would require XR If No 2. Any low- risk factors that allow safe assessment of ROM If Yes 3. AROM C- spine 45 bilat (regardless of pain) No XR needed if decision making algorithm leads to no XR Sn = 1 (95% CI ) SAell,

19 Predictors: Series #1 Any high- risk factors would require XR Age 65 Dangerous MOI Fall 1m/5 stairs, axial load to head, MVA ((>62mph, rollover, ejecaon), recreaaonal vehicle, bicycle)) Paresthesias in extremiaes If NO 38 Predictors: Series #2 Any low- risk factors that allow safe assessment of ROM Simple rear- end MVA (excludes pushed into oncoming traffic, hit by bus/large truck, rollover, hit by high- speed vehicle) Signg posiaon in ER Ambulatory at any Ame Delayed onset of neck pain (not immediate) Absence of mid- cervical tenderness If YES 39 19

20 Predictors: Series #3 AROM C- spine 45 bilat (regardless of pain) Decision: No low- risk factors present or pt is unable to rotate neck 45 in both direcaons 40 Ojawa Cervical Spine CPR Inclusion criteria ConsecuAve adult pts in ER s/p acute blunt trauma to head or neck Neck pain from any MOI No neck pain but visible injury proximal to clavicles, had not been ambulatory, and had sustained a dangerous MOI Glasgow coma scale of 15 Stable vital signs Systolic BP>90mmHg Respiratory rate per minute Exclusion criteria <16 years old Minor injuries (neg #1-2 inclusion) Glasgow coma scale <15 Grossly abnormal vital signs Injured >48 hours PenetraAng trauma Presented w/acute paralysis Known vertebral disease f/u same injury Pregnancy Pts w/o XR who could not be contacted on 2- wk f/u 41 20

21 Ojawa Cervical Spine CPR Demographics N=8,924 Mean age 36.7 (16) Prevalence clinically sig c- spine injury = 1.7% Female 48%

22 Canadian C- Spine Rule SAell, The CCR would have missed 1 paaent, NLC would have missed 15 paaents with important injuries RecommendaAon: Use CCR vs. NLC SAell,

23 46 NEXUS II CT s/p Head Injury Level II Predictors 1. Evidence of significant skull fx 2. Scalp hematoma 3. Neurologic deficit 4. Altered level of alertness 5. Abnormal behavior 6. Coagulopathy (clogng disorder) 7. Persistent vomiang 8. Age 65 CT Scan not indicated if NO variables present Sn = 0.98 (95% CI ) in all cases Sn = 0.95 (95% CI ) those w/ Glascow coma of

24 NEXUS II CT s/p Head Injury Inclusion criteria Blunt head trauma pts for whom CT scan was ordered Exclusion criteria PenetraAng trauma InfecAons CVA Tumors Other atraumaac indicaaons for CT Demographics N=13,728 Median age 37 Prevalence clinically important intracranial injuries = 6.7% Female 34% 48 A knee x- ray is only required for knee injury paaents with any of these findings: age 55 or over isolated tenderness of the patella (no bone tenderness of the knee other than the patella) tenderness at the head of the fibula inability to flex to 90 degrees inability to weight bear both immediately and in the casualty department (4 steps - unable to transfer weight twice onto each lower limb regardless of limping). 24

25 An ankle x- ray is required only if there is any pain in malleolar zone and any of these findings: bone tenderness at A bone tenderness at B inability to weight bear both immediately and in the casualty department. A foot x- ray is required if there is any pain in the midfoot zone and any of these findings: bone tenderness at C bone tenderness at D inability to weight bear both immediately and in the casualty department. QuesAons for Me 25