September 28, 2020

The SWIFFT Trial: To Cut or To Cast – That Is the Question

Background: FOOSH injuries, or falls onto outstretched hands, are a common presentation to the emergency department, and can frequently result in scaphoid fractures.  In fact, scaphoid fractures “account for 90% of all carpal fractures and 2-7% of all fractures” (Dias).  The most common location for a scaphoid fracture is within the scaphoid waist.  As with any fracture, in treating a scaphoid fracture, the goal is to stabilize fracture fragments in alignment to allow healing.  For scaphoid fractures, this can be accomplished with either casting to immobilize the wrist or by placing a screw through the fracture.  Traditional treatment strategy usually included plaster cast immobilization for 6-10 weeks, with operative fixation only for the roughly 10% of cases in which healing was unsatisfactory.  In recent years, however, there has been a trend toward early surgical intervention.  This trend results in higher costs and more invasive procedures, but is thought to speed recovery, allowing for earlier return to normal function.  In 2018, a systematic review and meta-analysis (14 trials with 765 patients) by Li et al compared surgical vs. non-surgical treatment of scaphoid waist fractures showed “no statistical difference in patient satisfaction, pain, and The Disability of the Arm, Shoulder, and Hand scores between surgical treatment and nonsurgical treatment.” Due to the variable quality of the data analyzed, the authors recommended further high-quality studies (Li).  

Paper:

  • Dias JJ et al. Surgery versus cast immobilisation for adults with a bicortical fracture of the scaphoid waist (SWIFFT): a pragmatic, multicentre, open-label, randomised superiority trial. Lancet 2020. PMID: 32771106

Clinical Question: 

  • For the treatment of scaphoid waist fractures displaced by 2mm or less, is treatment with surgical fixation superior to cast immobilization accompanied by early fixation of fractures to union failure in improving patient outcomes?

Image from Wikipedia [Link is HERE]

What They Did:

  • A pragmatic, parallel-group, multicenter, open-label, two-arm, randomised superiority trial of adults with scaphoid waist fractures that are displaced by 2mm or less.
    • Scaphoid waist is defined as the middle 60% of the scaphoid
    • 31 NHS hospitals in England and Wales
  • The authors designed the Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT) to compare early fixation with initial cast immobilization
  • Procedures:
    • Surgical Treatment Group 
      • Treatment via either percutaneous or open surgical fixation, per surgeon preference.
      • Implant type, surgical approach and postoperative management were not restricted
    • Cast Immobilization Group
      • Below-elbow cast immobilization for 6 -10 weeks, with or without inclusion of thumb
      • X-ray taken at 6 – 10 weeks was reviewed for nonunion and CT scan was performed if non-union was suspected
      • If CT confirmed non-union, immediate surgical fixation was offered
      • Surgery treatment then proceeded as above 
    • All subjects received standard physical therapy rehabilitation exercises with additional exercises given per the treating clinician
  • Patients completed the patient-related wrist evaluation (PRWE) questionnaire.  This questionnaire measures wrist pain and disability.   The total score ranges from 0 (no disability) to 100 (maximal loss of function and significant pain).  
  • Patients completed the questionnaire twice at baseline, once to recall any symptoms in the week prior to the injury, in an attempt to identify any underlying wrist symptoms and second to reflect their initial post injury status. 
  • PRWE was completed again at 6, 12, 26 and 52 weeks after enrollment
  • A prespecified difference of 6 points on the PRWE was set as likely to be notable and significant to patients.  
  • Bone union was assessed at baseline and 52 weeks via X-ray and CT scan

Outcomes:

  • Primary
    • Total PRWE score at 52 weeks
      • PRWE measures wrist pain and disability and contains 15 items, each with an 11-point ordered scale
      • The total score ranges from 0 (no disability) to 100 (maximum loss of function and marked pain)
      • A 6 point improvement in PRWE was deemed to be a conservative minimum clinically important difference
  • Secondary
    • PRWE pain and function subscale scores
    • 12-item Short Form Health Survey (SF-12) physical and mental component scores
    • Degree of bone union
    • Range of movement
    • Grip strength
    • Complications – defined as medical, surgical or cast-related and recorded at visits at 6, 12, and 52 weeks

Inclusion:

  • Skeletally mature
  • Age 16 or older
  • Presenting to National Health Service (NHS) hospital within 2 weeks of injury
  • Clear bicortical scaphoid waist fracture on plain radiograph
    • Defined as “a break in the continuity of both cortices on any radiographic view”
  • Displaced scaphoid fracture with a step or gap ≤2mm on any of five radiographic views
  • Available to have surgery within 2 weeks of presentation

Exclusion:

  • Fracture displaced by more than 2mm
  • Fractures involving the proximal or distal pole of the scaphoid
  • Trans-scaphoid-perilunate dislocation
  • Multiple injuries to the same arm
  • Concurrent wrist fracture of the opposite arm
  • Insufficient mental capacity to comply with treatment or data collection
  • Pregnancy
  • Patient not residing within the area to allow for follow up

Results:

  • 439 patients randomized
    • 408 patients included in primary analysis
    • Results were analyzed with covariance pattern mixed-effect linear regression model
    • Mean age of participants was 32.9 years
    • 83% of participants were male
    • 61% of participants had a fracture displacement of <1mm
    • Surgical group: 86% received surgery
    • Cast immobilization group: 97% received plaster cast
  • There was no statistically significant or clinically relevant difference in PRWE scores between the two groups at 52 weeks
    • Adjusted Mean (95% CI) at 52 weeks
      • Surgery group 11.9 (9.2 – 14.5)
      • Cast-immobilization group 14.0 (11.3 -16.6)
      • Mean difference -2.1 (-5.8 -1.6)
      • p-value 0.27

  • While patients were still in casts (6 and 12 weeks) there was a trend to improved pain and function scores in the surgery group, but given that the difference was less than 6 points on the PRWE scale (the difference preset by the researchers as likely to be relevant to patients) the clinical significance of this difference is uncertain. Beyond 12 weeks there was no notable difference. 
  • There was no significant difference in the PRWE subscales for pain or function, the SF-12 mental component scores, wrist range of motion or grip strength between either of the two groups.
  • Of the 220 patients randomized to the cast-immobilization group, 25 (11.4%) received surgery. 
  • There were fewer cases of non-union or slight union at 52 weeks in the surgery group, however, the difference was not significant (adjusted odds ratio 0.40 [95% CI 0.21-1.33]. p=0.13)
  • Potentially serious complications associated with surgery (infection, nerve problems and complex regional pain syndrome) occurred in 14% of the surgery group and only 1% of the cast immobilization group.
  • Minor cast related complications (cast too soft, too tight, broke, causing skin problems) occurred in 18% of the cast immobilization group and only 2% of the surgery group.

Strengths:

  • Multicenter, randomized clinical trial at 31 hospitals
  • Largest randomized trial comparing surgery with cast immobilization for treatment of adults with slight or no displacement of scaphoid waist fractures
  • Patient centered primary outcome
  • Randomization and analysis were appropriate to minimize bias in a study in which blinding was not an option
  • Analysis was done on intention-to-treat basis
  • Response bias minimized by repeated-measures model which allows for inclusion of patients with intermittent responses. 
  • Subgroup analysis was pre-planned
  • Baseline characteristics between groups were similar with the exception of ethnicity, education and smoking status
  • Performed a complier average causal effect (CACE) analysis.  This showed that non-compliance described in the study did not have an effect on the primary outcome
  • Number of large and small hospitals and surgeons involved increases generalizability of findings

Limitations:

  • Masking of trial participants or clinicians for outcome assessments was not possible.  When the primary outcome is a subjective one, this can influence the results, as is the case in this trial
  • Enrollment required that the patient have a clear scaphoid fracture on radiograph.  In emergency department patients, we often splint based on physical exam and clinical suspicion, therefore many of our patients may have been excluded from this study population. 
  • Inclusion of thumb in casting was not specified.  Function scores between those with casted thumb and free thumb could have been markedly different in the early weeks. 
  • The pragmatic nature of the trial allowed for freedom for the treating physician to follow their usual practice for cast immobilization, physical therapy and rehabilitation, surgical implant type, surgical approach and post-operative care, potentially introducing heterogeneity to the treatment plans.   However, authors note that this may make results relevant to more clinical settings and practice patterns.

Discussion:

  • Over a three period (2013 – 2016) the authors assessed 1047 patients for eligibility, 272 did not meet eligibility criteria and 336 refused to participate, leaving 439 randomly assigned patients.  This is still a huge cohort of patients with scaphoid fractures
  • At 6 to 12 weeks participants in the cast immobilization group, there was some evidence of a difference between the two groups, in terms of pain and function, favoring surgery, however the difference did not exceed 6 points on the PRWE
  • Beyond 12 weeks there was no difference between the two groups in terms of pain and function.  Additionally there was no evidence that the proportion of patients who had non-union and slight union of the fracture differed significantly between the two groups
  • Complications were 10x more likely in the early surgical fixation group (31 pts [14%]) compared to cast immobilization (3 pts [1%])
  • Reoperation was more frequent after early screw fixation in the surgery group (8 pts [4%]) compared to cast immobilization group (1 pts [<1%])
  • Long term consequences of arthritis, malunion, injury, and screw penetration will be investigated in a 5-year review of these participants
  • Unadjusted mean PRWE scores over time by patient treatment preference and fracture displacement at randomization:

Author Conclusion: “Adults who have bicortical scaphoid waist fracture displaced by 2mm or less that has been immobilised in a below-elbow cast have little difference in pain and function outcomes to those who have the fracture surgically fixed with a screw.”

Clinical Take Home Point:  Treatment of minimally displaced scaphoid waist fractures (≤2mm) with either cast immobilization and early fixation as needed or surgical fixation have similar outcomes with regard to patient pain and function scores, particularly at their long term (ie 26 and 52 week) follow up visits.  Utilization of more cast immobilization could reduce medical cost as well as surgical complications in these patients.  

References:

  1. Dias JJ et al. Surgery versus cast immobilisation for adults with a bicortical fracture of the scaphoid waist (SWIFFT): a pragmatic, multicentre, open-label, randomised superiority trial. Lancet 2020. PMID: 32771106
  2. Li H et al. Surgical versus nonsurgical treatment for scaphoid waist fracture with slight or no displacement: A meta-analysis and systematic review. Medicine (Baltimore). 2018. PMID: 30508914
  3. MacDermid JC et al. Patient rating of wrist pain and disability: a reliable and valid measurement tool. J Orthop Trauma. 1998. PMID: 9840793
  4. Ware J Jr et al. A 12-Item Short-Form Health Survey: construction of scales and preliminary tests of reliability and validity. Med Care. 1996. PMID: 8628042

For More Thoughts on this Topic:

Post Peer Reviewed By: Salim R. Rezaie, MD (Twitter: @srrezaie)

Cite this article as: Jenny Beck-Esmay, MD, "The SWIFFT Trial: To Cut or To Cast – That Is the Question", REBEL EM blog, September 28, 2020. Available at: https://rebelem.com/the-swifft-trial-to-cut-or-to-cast-that-is-the-question/.
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Jenny Beck-Esmay, MD

Jenny is the assistant residency director at the Department of Emergency Medicine at St. Luke's-Mount Sinai West in New York City. Originally from Minnesota, she moved to NYC to attend the New York University Tisch School of the Arts. After earning a BFA in drama, Jenny switched gears and turned to a career in medicine. She received her medical degree from the University of Minnesota Medical School and completed her emergency medicine residency at Bellevue-New York University. She is passionate about the medical education of learners at all levels. She has been involved in national and regional emergency medicine societies as the editor of the AAWEP newsletter, as a member of the Editorial Advisory Committee for EMResident and member of the NY ACEP Education Committee. In addition to serving as Editor-In-Chief of FemInEM, she is Associate Editor of R.E.B.E.L. EM, co-host of the CoreEM podcast, a contributor to EM:RAP and UC:RAP, and has spoken nationally and internationally at conferences including FIX, SMACC, Essentials of Emergency Medicine, and Rebellion in EM. She maintains an interest in the arts and literature and has a particular love of sci-fi, fantasy and comics.
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