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To compare the Short Musculoskeletal Function Assessment Dysfunction Index and the Short Form-36 Physical Component Summary scores among patients undergoing operative management of tibial fractures.
Between July 2000 and September 2005, we enrolled 1319 skeletally mature patients with open or closed fractures of the tibial shaft that were managed with intramedullary nailing. Patients were asked to complete the Short Musculoskeletal Function Assessment and Short Form-36 at discharge and 3, 6, and 12 months post surgical fixation.
Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores were highly correlated at 3, 6, and 12 months post surgical fixation. The difference in mean standardized change scores for the Short Musculoskeletal Function Assessment Dysfunction Index and the Short Form-36 Physical Component Summary, from 3 to 12 months post-surgical fixation, was not statistically significant. Both the Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores were able to discriminate between healed and non-healed tibial fractures at 3, 6, and 12 months post surgery.
In patients with tibial shaft fractures, the Short Musculoskeletal Function Assessment Dysfunction Index offered no important advantages over the Short Form-36 Physical Component Summary score. These results, along with the usefulness of the Short Form-36 for comparing populations, recommends the Short Form-36 for assessing physical function in studies of patients with tibial fractures.
The Short Musculoskeletal Function Assessment, based on the longer, 101-item Musculoskeletal Function Assessment questionnaire, is a two-part, 46-item, self-reported health-status questionnaire.1 One part, the Dysfunction Index, is designed to detect differences in the functional status of patients who have a broad range of musculoskeletal disorders that are commonly seen in community practices. The second part, the Bothersome Index, allows patients to evaluate how bothered they are by functional problems. Both Short Musculoskeletal Function Assessment indexes are scored from 0 to 100 and higher scores indicate poorer function.
The Short Form-36 is a widely accepted, well-validated functional status measure that was developed from the Medical Outcomes Study.2–4 It is a self-administered, 36-item questionnaire that measures health-related quality of life in eight domains that can be aggregated into a physical and a mental summary score. Each summary score is scored separately from 0 to 100, and lower scores indicate poorer function
Evidence suggests that, in general, disease-specific instruments (such as the Short Musculoskeletal Function Assessment) are able to detect small but important change – that is, they are more responsive – than are generic measures.5 Generic measures (such as the Short Form-36) facilitate comparisons to other populations. These considerations provide the rationale for the common use of both the Short Musculoskeletal Function Assessment and the Short Form-36 in current orthopaedic trials.6,7 Use of both instruments, however, increases the burden on both patients and researchers and may therefore adversely impact on trial feasibility. This study was designed to assess what is gained by adding the Short Musculoskeletal Function Assessment to the Short Form-36 in clinical trials of patients with tibial fractures.
From July 2000 to September 2005 we enrolled 1319 patients with open (Gustilo Type I–IIIb) and closed (Tscherne Type 0–3) tibial shaft fractures amenable to operative fixation with an intramedullary nail in a multi-centre, randomized controlled trial, the eponym for which is SPRINT (Study to Prospectively evaluate Reamed Intramedullary Nails in Tibial fractures). Each institution’s ethics review board approved the study, which was registered at Clinicaltrial.gov (Identifier: NCT00038129); readers can obtain details of the study design elsewhere.8
At discharge from hospital, patients rated their pre-injury status using the Short Musculoskeletal Function Assessment and Short Form-36. We have previously shown that patients undergoing lower limb orthopaedic surgery recall their preoperative quality of life, function, and general health at 2 weeks postoperative with sufficiently high accuracy to warrant substituting prospectively collected baseline data with recalled ratings.9 Patients completed the Short Musculoskeletal Function Assessment and Short Form-36 again at 3, 6, and 12 months post-surgery. Patients completed all questionnaires under the supervision of personnel trained to facilitate instrument completion without influencing responses. The role of supervising personnel was limited to reviewing respondents’ questionnaires after completion to confirm that each item was answered, and to draw attention to any contradictory responses and to provide respondents with the opportunity to make changes if they saw fit. Patients’ attending surgeons assessed fracture healing at each follow-up time on the basis of lateral and anterioposterior radiographs of patients’ fractures.
Our analyses, at each time point, were restricted to only those patients who provided completed Short Musculoskeletal Function Assessment and Short Form-36 questionnaires. When follow-up time differed from that specified in the protocol, we used follow-up to the scheduled time point closest to the actual follow-up. If two actual follow-up times were nearest to a single scheduled time-point, we used data from the actual follow-up closest to the scheduled time. We evaluated differences in patient characteristics between time-points with a t-test for normally distributed data and a chi-squared test for proportional data; we set our level of statistical significance at p<0.05. At each time point we calculated the Pearson correlation coefficient and associated 95% confidence interval between Short Musculoskeletal Function Assessment Dysfunction Index and SF-36 Physical Component Summary scores for all respondents. We explored the ability of the Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores to discriminate between patients who had, or had not, healed radiographically at each follow-up point with a paired t-test.
We calculated instrument responsiveness through a standardized response mean, the mean score change divided by the standard deviation of the score change.10 We compared the difference in standardized change scores for the Short Musculoskeletal Function Assessment Dysfunction Index and the Short Form-36 Physical Component Summary from 3 to 12 months with a paired t-test. We also tested whether the differences in standardized response means between the Short Form-36 Physical Component Summary and the Short Musculoskeletal Function Assessment Dysfunction Index were significant using the modified jack knife proceedure.11,12 In this analysis, each patient's standardized response mean was calculated as their individual change in score divided by the standard deviation of change in the whole cohort.
We centered the standardized response mean value for each instrument by subtracting the mean standardized response mean score from each individual standardized response mean score. Using linear regression, we predicted the differences in standardized response means between two different scales by including the centered standardized response mean value of one of the two instruments of interest as a predictor in the model; the dependant variable assures that either choice of instrument as a predictor will yield the same intercept. A significant intercept coefficient then represents a significant difference between standardized response means of the two instruments.
We explored the proportion of patients who achieved the minimally important difference in the Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores between each follow-up time with a McNemar test for 2 sets of observations on the same sample of patients; we set our level of significance at p<0.05.
We reviewed test scores at 3 months post-surgery to explore for a floor effect (scores reflecting the lowest level of functioning) in either Short Musculoskeletal Function Assessment Dysfunction Index or Short Form-36 Physical Component Summary scores. To explore for possible ceiling effects, scores reflecting optimal functioning, we examined patients’ estimated pre-injury Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores, provided at discharge, and the scores of all patients whose tibial fracture was declared healed at 3, 6, and 12 months follow-up. An instrument was considered to have floor/ceiling effects if >10% of scores were at the lowest or highest level of functioning.
Tibial fractures are often not isolated injuries and generic health related quality of life measures, such as the Short Form-36 Physical Component Summary, are influenced by co-morbidity. Thus, presence of co-morbidity may attenuate the signal of the tibial fracture on the Short Form-36. To explore this potential measurement issue we repeated all analyses of Short Form-36 Physical Component Summary and Short Musculoskeletal Function Assessment Dysfunction Index scores among patients with isolated tibial fractures (only one tibia fractured and no additional fractures or injuries) and patients with multi-trauma. All comparisons were 2-tailed and a p-value of < 0.05 was considered statistically significant.
Table 1 presents demographic data for our population. Response rates were 83% at discharge (n=1089), 69% at 3 months (n=906), 60% at 6 months (n=787), and 53% at 12 months post-surgery (n=700). There were no significant differences in patient characteristics between time-points. At all time points Short Musculoskeletal Function Assessment Dysfunction Index and SF-36 Physical Component Summary scores were strongly and significantly inversely correlated (Table 2). Both the Short Musculoskeletal Function Assessment Dysfunction Index and the Short Form-36 Physical Component Summary mean scores demonstrated statistically significant differences between patients with healed versus unhealed tibial fractures at 3, 6, and 12 months post-surgical fixation (Table 3).
There are no existing guidelines for the Short Musculoskeletal Function Assessment score difference that constitutes a minimally important difference. A 3 to 5 point change in score on a 0 to 100 scale is often cited as a meaningful threshold in evaluating patient changes in Short Form-36 scores, based on the work by Stewart and colleagues.13 More recent work by other authors has suggested that the smallest important difference may be larger than 3 to 5 points,14, 15 and a recent systematic review found that the threshold of discrimination for changes in the Short Form-36 is approximately half a standard deviation16. Applying this criterion to our data, the minimally important difference was approximately 7 points for the Short Musculoskeletal Function Assessment Dysfunction Index score and approximately 5 points for the Short Form-36 Physical Component Summary score, and the mean change in both instruments exceeded this importance threshold.
The proportion of patients who achieved a minimally important difference was significantly higher for Short Musculoskeletal Function Assessment Dysfunction Index scores from 3 to 6 months post-surgery than for Short Form-36 Physical Component Summary scores (Table 4). Differences in proportions from 6 to 12 months were not significant except when restricted to patients with isolated fractures, in which case Short Form-36 Physical Component Summary scores yielded a higher proportion of patients meeting the minimally important difference for improvement.
The modified jack knife approach (linear regression) found that differences in standardized response means of the Short Form-36 Physical Component Summary and Short Musculoskeletal Function Assessment Dysfunction Index from 3 to 12 months post-surgery were not significant (p=0.12). Changes in both instruments showed statistically significant improvement in function from 3 months to 12 months, and the standardized response means were very similar; any differences could be explained by chance (Table 2). With the exception of the Short Musculoskeletal Function Assessment Dysfunction Index which exhibited a ceiling effect (16.9% of respondents provided a score of zero) when patients were asked to rate their pre-injury status, we found no evidence of floor or ceiling effects for either Short Musculoskeletal Function Assessment or Short Form-36 Physical Component Summary scores in our population. Our results were similar when repeated on subpopulations of patients with isolated tibial fractures (Tale 5– Tale 7) and multi-trauma (data not shown).
We found that, in patients with tibial fractures, the Short Musculoskeletal Function Assessment Dysfunction Index and Short Form-36 Physical Component Summary scores are highly correlated, and demonstrate similar responsiveness and discriminative validity. We found no evidence of floor effects; however, a ceiling effect of the Short Musculoskeletal Function Assessment Dysfunction Index was found when patients estimated their pre-injury level of function. The presence of floor/ceiling effects would suggest limitations in an instrument’s ability to distinguish between patients with different levels of function due to clustering of scores at extremes. Ceiling effects also decrease an instrument’s ability to assess the patients’ improvement following injury due to clustering of patient’s scores at maximal recovery.17
The Short Musculoskeletal Function Assessment Dysfunction Index classifies patients as having achieved the minimally important difference earlier in the recovery process following surgical fixation of tibial fractures than the Short Form-36 Physical Component Summary score, and this difference appears to be greatest among patients presenting with multi-trauma. The significance of this earlier labelling is uncertain. No studies have empirically addressed the minimally important difference associated with the Short Musculoskeletal Function Assessment and we applied a somewhat arbitrary value of ½ the standard deviation as the minimally important difference for both instruments. Perhaps even more importantly, if one were using the instruments in randomized trials, a more pertinent quantity would be the difference in the proportion of patients who exceed the minimally important difference, and in this situation the particular threshold one uses for the minimally important difference makes little difference.18
The strengths of our study include a large sample size of patients presenting with similar injuries. Our study does have some limitations. After a patient’s fracture was declared healed by their attending surgeon they were no longer required to attend fracture clinic, which adversely impacted follow-up rates for quality of life instruments. Hence, our follow-up rates for completed Short Musculoskeletal Function Assessment and Short Form-36 questionnaires dropped from 83% at discharge to 53% at 12 months post-surgery.
To minimize respondent burden, we assessed pre-injury status, but not current status, with the Short Musculoskeletal Function Assessment and Short Form-36 questionnaires at discharge. This may have limited our ability to detect floor effects on instruments. Further, it remains possible that we would have found significant differences between standardized change scores of the Short Form-36 Physical Component Summary and the Short Musculoskeletal Function Assessment Dysfunction Index had we used discharge, rather than 3 months post-discharge, scores as our baseline.
Our use of estimates of pre-operative health status made post-operatively was based on the results of a previous study, conducted on a large population of patients undergoing elective arthroscopic knee surgery, that provided compelling evidence that patients can accurately recall their pre-operative state, 2 weeks post-operatively (intra-class correlation coefficient between pre-and post-operative assessments of pre-operative Short Form-36 Physical Component Summary scores was 0.81; 95% confidence interval = 0.75 to 0.86).8 We could not make the same assessment in the current study because we did not have pre-operative measures of health status. Our finding of a lower correlation between Short Form-36 Physical Component Summary and Short Musculoskeletal Function Assessment Dysfunction Index scores for estimates of pre-injury status in comparison to post-injury assessments (Table 2 & 6) was likely affected by the ceiling effect present with the Short Musculoskeletal Function Assessment. Alternative explanations may include that that our patients were less able to recall their pre-operative health state than patients undergoing elective arthroscopic knee surgery, or that patient’s pre-injury recall may be more reliable with the Short Form-36 Physical Component Summary (the instrument used in the previous study) than the Short Musculoskeletal Function Assessment Dysfunction Index.
Another limitation of our study is the uncertain significance of radiological healing of tibial fractures. Differences between mean instrument scores of radiographically healed and unhealed patients were statistically significant at all 3 time points we assessed, but their magnitude was relative small at 3 and 6-months post-discharge (Table 3 and Table 7). This suggests that radiographic healing of tibial fractures may have limitations as a surrogate for functional recovery.
The generalizability of our results to other populations is uncertain. For instance, a previous investigation found that the 101-item Musculoskeletal Function Assessment questionnaire had superior responsiveness and less ceiling and floor effects than the Short Form-36.19 The 444 patients who participated in this study were a highly diverse orthopaedic population, including 121 with upper extremity injuries.19 The Short Form-36 has minimal capacity to detect upper-extremity deficits as it has few items that specifically address upper-extremity function and this measure would, therefore, be more likely to exhibit ceiling effects.2 The existence of the arm/hand subscale of the Short Musculoskeletal Function Assessment is one potential advantage over the Short Form-36, and for that population the Short Musculoskeletal Function Assessment may have important advantages over the Short Form-36.
Kirschner et al. found that the Short Musculoskeletal Function Assessment demonstrated larger effect sizes than the Short Form-36 in 63 patients with primary osteoarthritis undergoing total knee arthroplasty.20 However, their analysis was inappropriate as they compared the effect size of the Short Musculoskeletal Function Assessment Dysfunction Index to all 8 domains of the Short Form-36, instead of comparing the Short Musculoskeletal Function Assessment Dysfunction Index to the Short Form-36 Physical Component Summary score. Obremskey and colleagues administered both the Short Musculoskeletal Function Assessment and the Short Form-36 on a single occasion to a group of 127 patients with isolated ankle fractures, managed operatively, an average of 27 months after their injury.21 They found equivalent measurement properties with the exception of floor effects in two of eight Short Form-36 domains. However, the Short Form-36 is typically reported according to Physical Component Summary or Mental Component Summary scores, and not as 8 domains.
Our findings also suggest that the additional information gained by administering both the Short Musculoskeletal Function Assessment Dysfunction Index and the Short Form-36 Physical Component Summary is insufficient to justify the respondent burden in trials of tibial fracture patients. Given the far more extensive use of the Short Form-36, more extensive validation, and ability to compare to other populations, we feel that the Short Form-36 Physical Component Summary score’s similar performance to the Short Musculoskeletal Function Assessment Dysfunction Index in patients with tibial fractures dictates the Short Form-36 as the instrument of choice for assessing physical function in these patients. Generalizing these results beyond this specific population is currently not warranted, and will require similar specific comparisons.
The following persons participated in the SPRINT Study:
Study Trial Co-Principal Investigators: Mohit Bhandari; Gordon Guyatt; Steering Committee: Chair: Gordon Guyatt; Mohit Bhandari; David W. Sanders; Emil H. Schemitsch; Marc Swiontkowski; Paul Tornetta III; Stephen D. Walter; Central Adjudication Committee: Chair: Gordon Guyatt; Mohit Bhandari; David W. Sanders; Emil H. Schemitsch; Marc Swiontkowski.; Paul Tornetta III; Stephen D. Walter; Steering / Adjudication / Writing Committee: Chair: Gordon Guyatt; Mohit Bhandari; David W. Sanders; Emil H. Schemitsch; Marc Swiontkowski; Paul Tornetta III; Stephen D. Walter; SPRINT Methods Centre Staff: McMaster University, Hamilton, Ontario: Sheila Sprague; Diane Heels-Ansdell; Lisa Buckingham; Pamela Leece; Helena Viveiros; Tashay Mignott; Natalie Ansell; Natalie Sidorkewicz; University of Minnesota, Minneapolis, Minnesota: Julie Agel; Data Safety and Monitoring Board: Chair: Claire Bombardier; Jesse A. Berlin; Michael Bosse; Bruce Browner; Brenda Gillespie; Alan Jones; Peter O’Brien; Site Audit Committee: Julie Agel; Sheila Sprague; Rudolf Poolman; Mohit Bhandari.
Investigators: London Health Sciences Centre / University of Western Ontario, London, Ontario: David W. Sanders; Mark D. Macleod; Timothy Carey; Kellie Leitch; Stuart Bailey; Kevin Gurr; Ken Konito; Charlene Bartha; Isolina Low; Leila V. MacBean; Mala Ramu; Susan Reiber; Ruth Strapp; Christina Tieszer; Sunnybrook Health Sciences Centre / University of Toronto, Toronto, Ontario: Hans J. Kreder; David J. G. Stephen; Terry S. Axelrod; Albert J.M. Yee; Robin R. Richards; Joel Finkelstein; Wade Gofton; John Murnaghan; Joseph Schatztker; Michael Ford; Beverly Bulmer; Lisa Conlan; Hospital du Sacre Coeur de Montreal, Montreal, Quebec: G.Yves Laflamme; Gregory Berry; Pierre Beaumont; Pierre Ranger; Georges-Henri Laflamme; Sylvain Gagnon; Michel Malo; Julio Fernandes; Marie-France Poirier; St. Michael’s Hospital / University of Toronto, Toronto, Ontario: Emil H. Schemitsch; Michael D. McKee; James P. Waddell; Earl R. Bogoch; Timothy R. Daniels; Robert R. McBroom; Milena R. Vicente; Wendy Storey; Lisa M. Wild; Royal Columbian Hospital / University of British Columbia, New Westminster/Vancouver, British Columbia: Robert McCormack; Bertrand Perey; Thomas J. Goetz; Graham Pate; Murray J. Penner; Kostas Panagiotopoulos; Shafique Pirani; Ian G. Dommisse; Richard L. Loomer; Trevor Stone; Karyn Moon; Mauri Zomar; Wake Forest Medical Center / Wake Forest University Health Sciences, Winston-Salem, North Carolina: Lawrence X. Webb; Robert D. Teasdall; John Peter Birkedal; David Franklin Martin; David S. Ruch; Douglas J. Kilgus; David C. Pollock; Mitchel Brion Harris; Ethan Ron Wiesler; William G. Ward; Jeffrey Scott Shilt; Andrew L. Koman; Gary G. Poehling; Brenda Kulp; Boston Medical Center / Boston University School of Medicine, Boston, Massachusetts: Paul Tornetta III; William R. Creevy; Andrew B. Stein; Christopher T. Bono; Thomas A. Einhorn; T. Desmond Brown; Donna Pacicca; John B. Sledge III; Timothy E. Foster; Ilva Voloshin; Jill Bolton; Hope Carlisle; Lisa Shaughnessy; Wake Medical Center, Raleigh, North Carolina: William T. Obremskey; C. Michael LeCroy; Eric G. Meinberg; Terry M. Messer; William L. Craig III; Douglas R. Dirschl; Robert Caudle; Tim Harris; Kurt Elhert; William Hage; Robert Jones; Luis Piedrahita; Paul O. Schricker; Robin Driver; Jean Godwin; Vanderbilt University Medical Center, Nashville, Tennessee: William T. Obremskey; Philip James Kregor; Gregory Tennent; Lisa M. Truchan; Marcus Sciadini; Franklin D. Shuler; Robin E. Driver; Mary Alice Nading; Jacky Neiderstadt; Alexander R. Vap; MetroHealth Medical Center, Cleveland, Ohio: Heather A. Vallier; Brendan M. Patterson; John H. Wilber; Roger G. Wilber; John K. Sontich; Timothy Alan Moore; Drew Brady; Daniel R. Cooperman; John A. Davis; Beth Ann Cureton; Hamilton Health Sciences, Hamilton, Ontario: Scott Mandel; R. Douglas Orr; John T.S. Sadler; Tousief Hussain; Krishan Rajaratnam; Bradley Petrisor; Mohit Bhandari; Brian Drew; Drew A. Bednar; Desmond C.H. Kwok; Shirley Pettit; Jill Hancock; Natalie Sidorkewicz; Regions Hospital, St. Paul, Minnesota: Peter A. Cole; Joel J. Smith; Gregory A. Brown; Thomas A. Lange; John G. Stark; Bruce A. Levy; Marc F. Swiontkowski; Mary J. Garaghty; Joshua G. Salzman; Carol A. Schutte; Linda Tastad; Sandy Vang; University of Louisville School of Medicine, Louisville, Kentucky: David Seligson; Craig S. Roberts; Arthur L. Malkani; Laura Sanders; Carmen Dyer; Jessica Heinsen; Langan Smith; Sudhakar Madanagopal; Linda Frantz-Bush; Memorial Hermann Hospital, Houston, Texas: Kevin J. Coupe; Jeffrey J. Tucker; Allen R. Criswell; Rosemary Buckle; Alan Jeffrey Rechter; Dhiren Shaskikant Sheth; Brad Urquart; Thea Trotscher; Erie County Medical Center / University of Buffalo, Buffalo, New York: Mark J. Anders; Joseph M. Kowalski; Marc S. Fineberg; Lawrence B. Bone; Matthew J. Phillips; Bernard Rohrbacher; Philip Stegemann; William M. Mihalko; Cathy Buyea; University of Florida – Jacksonville, Jacksonville, Florida: Stephen J. Augustine; William Thomas Jackson; Gregory Solis; Sunday U. Ero; Daniel N. Segina; Hudson B. Berrey; Samuel G. Agnew; Michael Fitzpatrick; Lakina C. Campbell; Lynn Derting; June McAdams; Academic Medical Center, Academic Medical Center, Amsterdam, The Netherlands: J. Carel Goslings; Kees Jan Ponsen; Jan Luitse; Peter Kloen; Pieter Joosse; Jasper Winkelhagen; Raphaël Duivenvoorden; University of Oklahoma Health Science Center, Oklahoma City, Oklahoma: David C. Teague; Joseph Davey; J. Andy Sullivan; William J. J. Ertl; Timothy A. Puckett; Charles B. Pasque; John F. Tompkins II; Curtis R. Gruel; Paul Kammerlocher; Thomas P. Lehman; William R. Puffinbarger; Kathy L. Carl; University of Alberta / University of Alberta Hospital / Royal Alexandra Hospital, Edmonton, Alberta: Donald W. Weber; Nadr M. Jomha; Gordon R. Goplen; Edward Masson; Lauren A. Beaupre; Karen E. Greaves; Lori N. Schaump; Greenville Hospital System, Greenville, South Carolina: Kyle J. Jeray; David R. Goetz; David E. Westberry; J. Scott Broderick; Bryan S. Moon; Stephanie L. Tanner; Foothills General Hospital, Calgary, Alberta: James N. Powell; Richard E. Buckley; Leslie Elves; Saint John Regional Hospital, Saint John, New Brunswick: Stephen Connolly; Edward P. Abraham; Trudy Steele; Oregon Health & Sciences University, Portland, Oregon: Thomas Ellis; Alex Herzberg; George A. Brown; Dennis E. Crawford; Robert Hart; James Hayden; Robert M. Orfaly; Theodore Vigland; Maharani Vivekaraj; Gina L. Bundy; University of California, San Francisco, San Francisco General Hospital, San Francisco, California: Theodore Miclau III; Amir Matityahu; R. Richard Coughlin; Utku Kandemir; R. Trigg McClellan; Cindy Hsin-Hua Lin; Detroit Receiving Hospital, Detroit, Michigan: David Karges; Kathryn Cramer; J. Tracy Watson; Berton Moed; Barbara Scott; Deaconess Hospital Regional Trauma Center and Orthopaedic Associates, Evansville, Indiana: Dennis J. Beck; Carolyn Orth; Thunder Bay Regional Health Science Centre, Thunder Bay, Ontario: David Puskas; Russell Clark; Jennifer Jones; Jamaica Hospital, Jamaica, New York: Kenneth A. Egol; Nader Paksima; Monet France; Ottawa Hospital – Civic Campus, Ottawa, Ontario: Eugene K. Wai; Garth Johnson; Ross Wilkinson; Adam T. Gruszczynski; Liisa Vexler.
Funding: This Study was funded by Research Grants from the Canadian Institutes of Health Research # MCT-38140 [PI: G. Guyatt], National Institutes of Health NIAMS-072; R01 AR48529 [PI: M. Swiontkowski], Orthopaedic Research and Education Foundation [American Academy of Orthopaedic Surgeons [PI: P. Tornetta III], Orthopaedic Trauma Association [PI: M. Bhandari]. Smaller site-specific grants were also obtained from Hamilton Health Sciences Research Grant [PI: M. Bhandari] and Zimmer [PI: M. Bhandari]. No funds were received for the preparation of this manuscript. Dr. Jason W. Busse is funded by a New Investigator Award from the Canadian Institutes of Health Research and Canadian Chiropractic Research Foundation. Dr. Mohit Bhandari is supported, in part, by a Canada Research Chair, McMaster University.
Role of Funding Agencies: The funding sources had no role in design or conduct of the study; the collection, management, analysis, or interpretation of the data; or the preparation, review, or approval of the manuscript.
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Trial Registration: The SPRINT trial was registered [ID NCT00038129] at http://clinicaltrials.gov/ct/show/NCT00038129
Competing interests: Dr. Marc Swiontkowski was an original developer of the Short Musculoskeletal Function Assessment Questionnaire.