PMID- 32224628
OWN - NLM
STAT- MEDLINE
DCOM- 20210312
LR  - 20210312
IS  - 2329-9185 (Electronic)
IS  - 2329-9185 (Linking)
VI  - 8
IP  - 2
DP  - 2020 Feb
TI  - Revisiting the Sample Size and Statistical Power of Randomized Controlled Trials 
      in Orthopaedics After 2 Decades.
PG  - e0079
LID - 10.2106/JBJS.RVW.19.00079 [doi]
AB  - BACKGROUND: A study published in 2001 reported that sample sizes in the 
      randomized controlled trials (RCTs) published in major orthopaedic journals in 
      1997 were too small, resulting in low power to detect reasonable effect sizes. 
      Low power is the fundamental reason for the poor reproducibility of research 
      findings and serves to erode a cornerstone of the scientific method. The aim of 
      this study was to ascertain whether improvements have been made in orthopaedic 
      research during the past 2 decades. METHODS: The electronic table of contents 
      from the 2016 and 2017 volumes of 7 major orthopaedic journals were searched 
      issue by issue in chronological order to identify possible RCTs. A posteriori 
      (after-the-fact) power to detect small, medium, and large effect sizes, defined 
      by the Cohen d value, were calculated from the sample sizes reported in the 
      studies. The power to detect effect sizes associated with the most commonly used 
      patient-reported outcome measures (PROMs) was also calculated. Finally, the use 
      of a priori power analysis in the included studies was assessed. RESULTS: In 
      total, 233 studies were included in the final analyses. None of the negative 
      studies had sufficient power (>/=0.80) to detect a small effect size. Only between 
      15.0% and 32.1% of the negative studies had adequate power to detect a medium 
      effect size. When categorized by anatomic region, 0% to 52.6% had adequate power 
      to detect an effect size corresponding to the minimal clinically important 
      difference (MCID). An a priori power analysis was employed in 196 (84%) of the 
      233 studies. However, the power analysis could not be replicated in 46% of the 
      studies that used a mean comparison. CONCLUSIONS: Although small improvements in 
      orthopaedic RCTs have occurred during the past 2 decades, many RCTs are still 
      underpowered: the sample sizes are still too small to have adequate power to 
      detect what would be deemed clinically relevant.
FAU - Reito, Aleksi
AU  - Reito A
AD  - Department of Orthopaedics, Tampere University and Tampere University Hospital, 
      Tampere, Finland.
AD  - Department of Medicine and Health Technology, Tampere University, Tampere, 
      Finland.
AD  - Department of Surgery, Central Finland Central Hospital, Jyvaskyla, Finland.
FAU - Raittio, Lauri
AU  - Raittio L
AD  - Department of Medicine and Health Technology, Tampere University, Tampere, 
      Finland.
FAU - Helminen, Olli
AU  - Helminen O
AD  - Department of Surgery, Central Finland Central Hospital, Jyvaskyla, Finland.
AD  - Department of Surgery, Oulu University Hospital, Oulu, Finland.
LA  - eng
PT  - Journal Article
PT  - Systematic Review
PL  - United States
TA  - JBJS Rev
JT  - JBJS reviews
JID - 101674872
SB  - IM
MH  - Humans
MH  - Orthopedics/*trends
MH  - *Randomized Controlled Trials as Topic
MH  - *Sample Size
EDAT- 2020/04/01 06:00
MHDA- 2021/03/13 06:00
CRDT- 2020/04/01 06:00
PHST- 2020/04/01 06:00 [entrez]
PHST- 2020/04/01 06:00 [pubmed]
PHST- 2021/03/13 06:00 [medline]
AID - 01874474-202002000-00007 [pii]
AID - 10.2106/JBJS.RVW.19.00079 [doi]
PST - ppublish
SO  - JBJS Rev. 2020 Feb;8(2):e0079. doi: 10.2106/JBJS.RVW.19.00079.