A proximal femoral fracture is one of the most common reasons for admission to an orthopedic service.1 Operative fixation is the mainstay of treatment for femoral neck fractures in younger and elderly patients with undisplaced fractures.2 The goals of operative fixation are preserving the native joint, providing pain relief, promoting early mobilization, and decreasing mortality. Internal fixation for femoral neck fractures is most commonly performed with multiple parallel screws or a sliding hip screw.3 Both of these constructs allow for fracture compression to promote healing.3 However, these methods of fixation may also lead to excessive shortening of the femoral neck from compression during axial loading, changing the moment arm for the hip abductors and the overall mechanics of gait.3,4
Evidence suggests that femoral neck shortening results in inferior hip function.3,5–7 Because femoral neck shortening occurs in up to 50%–60% of patients after internal fixation of femoral neck fractures,3,8 it is important to better understand its association with physical functioning in these patients. Furthermore, if femoral neck shortening is associated with adverse outcomes, it may be prudent to investigate a different fixation implant that does not allow for excessive shortening while simultaneously leading to successful fracture healing.
Small cohorts and nonspecific measurements of health-related outcomes have limited previous studies assessing the relationship between femoral neck shortening and hip function. We conducted a secondary analysis of the “Fixation using Alternative Implants for the Treatment of Hip fractures” (FAITH) trial9 to analyze functional outcomes after internal fixation in patients 50 years of age or older using the Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) questionnaire. We hypothesized that increased femoral neck fracture shortening would be associated with inferior hip function.
Study Design and Patients
We performed a secondary analysis of the FAITH trial data. The protocol for the FAITH trial has been previously described in detail.9 Briefly, FAITH was a multicenter, randomized controlled trial that compared the sliding hip screw versus multiple cancellous screws for the fixation of femoral neck fractures.9 Patients included were men and women 50 years of age or older who had an isolated femoral neck fracture and underwent timely (within 72 hours of injury) operative fixation of the fracture.9 Patients excluded were those not suitable for internal fixation secondary to pre-existing conditions such as severe osteoarthritis or disorders bone metabolism, associated major injuries of the lower extremity, retained hardware or infection around the affected hip, or problems that would interfere with assessment of the primary outcome or follow-up.9 After informed consent, patients were randomized to receive a sliding hip screw or cancellous screws for fixation of their femoral neck fractures. Patients were recruited from 81 clinical centers internationally and enrolled in the study between March 2008 and March 2014.9 This secondary analysis includes only patients with healed fractures and a completed WOMAC questionnaire at 24 months after injury. Only patients with healed fractures were included in this study to minimize bias related to inferior functional outcomes secondary to nonunion.
Data were obtained from Centre for Evidence-Based Orthopaedics (McMaster University), which coordinated the FAITH trial. Based on the trial protocol, study participants returned for clinical follow-up at routine time intervals for up to 24 months. At each follow-up, patients completed clinical assessments and radiographs per the discretion of the treating surgeon. A subset of participants at all clinical sites completed the WOMAC questionnaire and other measures of health-related quality of life (HRQoL).9 WOMAC and HRQoL measures were no longer collected once a sufficient number of patients had enrolled, based on the sample size estimates allowing for secondary HRQoL comparisons between groups.
Femoral Neck Shortening
An independent Central Adjudication Committee (CAC) reviewed radiographic characteristics, quality of surgery, fracture healing, reoperations, fracture-related complications, and mortality after the 24-month follow-up.9 The committee consisted of 4 orthopedic surgeons with experience in hip fracture care and clinical trial adjudication. The committee members adjudicated all available radiographic data from visits at and after the week 10 time point.9 Contralateral hip radiographs were not collected or reviewed per the trial protocol. Femoral neck shortening was measured as a categorical variable and classified into one of the following groups, as determined by the CAC (Fig. 1): no shortening, mild shortening (≤5 mm), moderate shortening (6–10 mm), or severe shortening (>10 mm).9 These predetermined classifications of femoral neck shortening were established in the FAITH trial design based on categories previously described in the literature and consistent with a pragmatic clinical approach to classify the magnitude of shortening.3–5,8 Shortening was measured on the anteroposterior radiograph along the long axis of the femoral neck by comparing the position of the fixation implant between the intraoperative or immediate postoperative film compared with the last available follow-up radiograph Members of the CAC were unable to standardize hip rotation at the time of x-ray secondary or review contralateral hip radiographs due to the pragmatic nature of the study in assessing for shortening; however, they were able to account for variable x-ray magnification based on the diameter of the fixation implants. This technique has been used in other studies measuring femoral neck shortening and it is a pragmatic approach similar to Serrano et al,10 although it only uses the known screw diameter and not the screw length. Unpublished data determined that measuring the change in screw position, and using the screw diameter to adjust for magnification, has high inter-rater reliability (intraclass correlation coefficient = 0.96) and underestimates the amount of shortening by an average of 0.5 mm (95% confidence interval, 0.37–0.64 mm).
Hip Function Assessment
The primary outcome for the current analysis was hip function, as measured by the WOMAC questionnaire, at 24 months after injury. The WOMAC is an extensively validated, disease-specific, self-administered questionnaire that is one of the most widely used self-reported measures of lower extremity symptoms and function.11,12 The questionnaire contains 24 items with 3 subscales that evaluate pain, stiffness, and physical function.11,12 It is scored from 0 to 96, with higher scores representing inferior function.11
Patient factors include the following: age, sex, race, body mass index (BMI), mechanism of injury, any additional injuries, American Society of Anesthesiologists (ASA) physical status classification, smoking status, prefracture living status and function, fracture classification, type of reduction, and rehabilitation. Prefracture living status includes whether the patient was institutionalized or not, and prefracture function refers to whether a patient was an independent ambulator or used a walking aid, such as a cane or a walker. Rehabilitation refers to the patient's discharge location, such as to home or to a rehabilitation facility and their progression from that point.
The covariates of age and fracture displacement were chosen a priori to assess for effect measure modification. Previously published evidence shows that the association between femoral neck shortening and hip function may differ when stratified by these variables.7–9,13
All analyses were performed using SAS University Edition (SAS Institute Inc, Cary, NC). We performed a univariate analysis to characterize baseline patient characteristics and variables of interest. We reported counts and percentage for nominal data, and mean and SD for continuous variables. The association between femoral neck shortening and hip function was estimated using linear regression. We performed tests of interaction using a linear regression model to assess for effect measure modification. We included independent variables in a multivariable linear regression model if they were confounders. To assess for confounding, we analyzed the association between covariates and femoral neck shortening using a χ2 test or Fisher's exact test, and the association between covariates and WOMAC score using linear regression. If the P value was less than 0.05, then the covariate was considered to be associated with shortening or WOMAC score. To identify a confounder, we compared crude estimates to adjusted estimates, which were obtained by adding each covariate to the model and obtaining a parameter estimate. If the percent change in estimate was 10% or greater, then the covariate was considered a confounder and was added to the linear regression model.
In the FAITH trial, 1108 patients were randomized to receive operative fixation with a sliding hip screw or cancellous screws between March 3, 2008, and March 31, 2014, and 1079 patients were eligible to be included in the FAITH analyses (Fig. 2).9 Two hundred eighty-four patients did not have radiographs available for fracture adjudication and therefore were not included in the fracture healing analysis. Of these 795 patients remaining, 532 patients achieved radiographic union within 24 months of clinical follow-up; however, only 350 patients completed a WOMAC questionnaire at 24 months after fracture (the final sample).
As shown in Table 1, the majority of patients were 50–80 years of age (n = 285, 81%) and white (n = 336, 96%). Slightly more than half of the patients were female (n = 218, 62%) and underweight (BMI <18.5) to normal (BMI 18.5–25) BMI (n = 214, 61%). Most patients fractured their hip by falling (n = 338, 97%) and did not sustain other injuries (n = 308, 88%). Furthermore, three-quarters of the patients were relatively healthy with an ASA classification of I or II (n = 261, 74%). About half of the patients were never smokers (n = 169, 48%), while the rest were current or former smokers (n = 181, 52%).
As shown in Table 2, the majority of subjects had undisplaced fractures (n = 249, 71%). In terms of surgical treatment, the patients were split evenly between sliding hip screw (n = 176, 50%) and cancellous screws (n = 174, 50%), with very few requiring open reduction (n = 17, 5.0%). Over half the patients were discharged to home after their hospitalization (n = 224, 64%), and the majority were living at home by 24 months after fracture (n = 326, 93%). Two-thirds of the patients healed with either no or mild femoral neck shortening (≤5 mm) (n = 238, 68%), whereas the other one-third experienced moderate or severe shortening (>5 mm) (n = 112, 32%).
Overall Adjusted Association
We found a significant association between shortening and WOMAC score (P < 0.01) when adjusting for surgical treatment (Table 3). We did not find age or type of fracture to be effect measure modifiers (P = 0.9663 and P = 0.3250, respectively). Type of fracture reduction and displacement were both associated with femoral neck shortening (P < 0.001 for both, using Fisher's exact test for the association between type of fracture reduction and shortening and a χ2 test for the association between fracture displacement and shortening); however, they did not contribute significantly to the final multivariable linear regression model (P = 0.7057 for reduction and P = 0.6769 for displacement when added to the model adjusted for surgical treatment) and were thus excluded. Although surgical treatment was not associated with femoral neck shortening or WOMAC score, we chose to include it in our final linear regression model secondary to its clinical importance in the original FAITH trial design. We also tested for interaction between treatment group and smoking status based on their significance in the FAITH trial, but this was not significant and therefore not included in the final multivariable linear regression model. We found that as femoral neck shortening increased, so did the mean WOMAC score, indicating inferior hip function (P < 0.01). In the “no shortening” group, the WOMAC score was 37.9; in the “mild” group, the score was 43.4; in the “moderate” group, the score was 44.1; and in the “severe” group, the score was 44.6. The mean WOMAC score for the cohort was 42.5. There were also significant differences in mean WOMAC scores between patients with mild and no shortening (5.5, P < 0.01), moderate and no shortening (6.2, P < 0.01), and severe and no shortening (6.7, P = 0.02).
We found that no/mild shortening (≤5 mm) was present in two-thirds of patients, while moderate/severe shortening (>5 mm) was present in one-third of patients. We found that hip function worsened as femoral neck shortening increased, and there was a significant association between shortening and hip function.
Compared with previous reports, our cohort included a higher number of patients with no or mild shortening and fewer patients with moderate and severe shortening. Zlowodski et al4 estimated no/mild shortening (<5 mm) in 34%, moderate shortening (5–10 mm) in 36%, and severe shortening (>10 mm) in 30% in patients with undisplaced fractures who received treatment with multiple cancellous screws. Stockton et al8 found moderate femoral neck shortening (≥5 and <10 mm) in 22% and severe shortening (≥10 mm) in 32% of patients ages 60 years or younger who received fixation with multiple cancellous screws or sliding hip screw. Slobogean et al7 estimated 22.8% had moderate shortening (5–10 mm) and 12.9% had severe shortening (≥10 mm) in patients younger than 55 years who received fixation with multiple cancellous screws; these numbers are the most consistent with our findings. The differences between our study and the literature may be secondary to cohort size, type of surgical treatment, or patient population. Alternatively, our findings may be different secondary to the methodologies used to assess shortening.
Our findings that hip function worsens with increasing femoral neck shortening are consistent with the literature. Slobogean et al7 found that patients under the age of 55 years with femoral neck shortening >10 mm had a mean Harris Hip Score 9.9 points lower than patients with less shortening at 12 months after fixation. Similarly, Zlowodzki et al3 found that physical functioning scores decreased in a gradient fashion as shortening increased after internal fixation with cancellous screws for undisplaced femoral neck fractures. They found differences in scores related to the degree of shortening, indicating poor functional outcomes with a greater degree of shortening.3 Weil et al5 reported a statistically negative correlation between SF-12 score and overall neck shortening after fixation with multiple screws. More recently, Crosby and Parker14 found that one year after internal fixation for displaced hip fracture, femoral neck shortening of greater than 15 mm was associated with increased residual pain and loss of mobility.
Although our findings are clinically relevant to the orthopedic trauma population, the results should be interpreted in the context of the study design. The WOMAC questionnaire, while reliable, has no normative data available for hip fracture patients.11 More importantly, the minimal clinically important differences score for the WOMAC has not been well-established in the hip fracture population. However, in 2014, SooHoo et al15 recently described a potentially relevant minimal clinically important difference estimate of 10.21 from a cohort of patients at 3 months postoperatively who underwent either total hip or total knee arthroplasty. Our results do not quite meet this 10-point change between no shortening and severe shortening but are still relevant in comparison with current literature. For example, Aprato et al16 in 2011 examined patient's health-related quality of life after THA for intracapsular femoral neck fracture and noted a mean global WOMAC score of 33.1 at an average follow-up time of 2.4 years postoperatively. Our study revealed a mean WOMAC score of 47.2, which is about 14 points higher than the number estimated by Aprato; therefore, it may be considered a clinically relevant difference in hip function between patients treated with THA and internal fixation.
Our study has several limitations. It is a retrospective study of previously prospectively collected data from the FAITH trial. We were only able to analyze 350 patients of more than 1000 patients who were included in the initial FAITH trial secondary to available previously collected data, and therefore, our study population may not match the larger trial population. Although we were able to analyze a large number of variables from the data set, there were some that were unavailable for our final analysis (such as whether a patient had a previous diagnosis of osteoporosis or specific postoperative complications). Similarly, we were unable to determine whether the strength of the association between shortening and functional outcome varied with increasing age because age was reported as above or below 80 years in the original trial data set. Therefore, our final model may not account for all possible confounders, and as a result, the estimated association between femoral neck shortening and hip function may have unknown underlying bias. In addition, quality of reduction was not included as a covariate in our analysis because less than 0.5% of participants in the FAITH trial were deemed to have an unacceptable quality of reduction by the Central Adjudication Committee.9 However, while anatomical reduction is required for optimum stability, rotational malalignment cannot be easily judged from plain radiographs. The FAITH adjudication committee did their best to determine acceptable reduction but they were not judging reductions as unacceptable versus acceptable as opposed to “perfect” or “anatomic.” Finally, we do not know the causal effect of a shortened femoral neck. Although the WOMAC captures certain information regarding a patient's pain, stiffness, and physical function, the actual effect of decreased function remains unknown. Regardless, for these patients, shortening is on the causal pathway between fracture fixation, fracture healing, and final functional outcome.
Despite its limitations, this study has a number of strengths. At 350 patients, it represents the largest multicenter cohort to date assessing the association between femoral neck shortening and hip function. In addition, our cohort included both patients treated with cancellous screws or a sliding hip screw, the 2 most common surgical implants used for internal fixation of femoral neck fractures. Therefore, these results are generalizable to the most common internal fixation methods for femoral neck fractures. Furthermore, the original trial used an independent adjudication committee to determine healing and shortening measurements, which ensures consistency across all patients and removes potential for bias from the treating surgeon. Finally, the WOMAC questionnaire is a highly sensitive measure of hip function and that has been frequently used in this population.11,12
In summary, we found that there is a strong association between femoral neck shortening and hip function among patients 50 years and older who received internal fixation for a femoral neck fracture. While this subsequent secondary analysis of data from the FAITH trial confirms the association between shortening and hip function after fixation with the 2 most common implants, it is unknown if fixation devices that limit the amount of fracture collapse could achieve similar healing success, avoid excessive fracture shortening, and improve functional outcomes. When choosing to perform internal fixation for a femoral neck fracture, surgeons must remain cognizant that >5 mm of fracture shortening is associated with inferior hip functional outcomes.
APPENDIX 1. FAITH Investigators
Mohit Bhandari (Chair, McMaster University), Marc Swiontkowski (University of Minnesota), P. J. Devereaux (McMaster University), Gordon Guyatt (McMaster University), Martin J. Heetveld (Spaarne Gasthuis, Haarlem), Kyle Jeray (Greenville Health System), Susan Liew (The Alfred), Martin Richardson (University of Melbourne), Emil H. Schemitsch (University of Western Ontario), Lehana Thabane (McMaster University), Paul Tornetta III (Boston University Medical Center), and Stephen D. Walter (McMaster University).
Global Methods Center
Mohit Bhandari (Principal Investigator); Sheila Sprague (Research Methodologist); Paula McKay (Manager); Taryn Scott, Alisha Garibaldi, Helena Viveiros, Marilyn Swinton, (Research Coordination); Mark Gichuru, Sofia Bzovsky (Adjudication Coordination); Diane Heels-Ansdell, Qi Zhou (Statistical Analysis); Lisa Buckingham, Aravin Duraikannan (Data Management); and Deborah Maddock, Nicole Simunovic (Grants Management) (McMaster University).
United States Methods Center
Marc Swiontkowski (Principal Investigator) and Julie Agel (Research Coordination) (University of Minnesota).
Netherlands Method Center: Martin J. Heetveld (Principal Investigator); Esther M. M. Van Lieshout (Research Coordination); and Stephanie M. Zielinski (Trial Coordination) (Erasmus MC, University Medical Center Rotterdam).
United Kingdom Method Center
Amar Rangan (Principal Investigator), Birgit C. Hanusch, Lucksy Kottam, and Rachel Clarkson (Research Coordination) (The James Cook University Hospital).
Gregory J. Della Rocca (Chair) (Duke University), Robert Haverlag (Onze Lieve Vrouwe Gasthuis), Susan Liew (The Alfred), Gerard P. Slobogean (University of Maryland, Baltimore), and Kyle Jeray (Greenville Health System).
Participating Clinical Sites
Canada: Robert McCormack, Kelly Apostle, Dory Boyer, Farhad Moola, Bertrand Perey, Trevor Stone, Darius Viskontas, H. Michael Lemke, Mauri Zomar, Karyn Moon, Raely Moon, Amber Oatt (Royal Columbian Hospital/Fraser Health Authority/University of British Columbia); Richard E. Buckley, Paul Duffy, Robert Korley, Shannon Puloski, James Powell, Kelly Johnston, Kimberly Carcary, Melissa Lorenzo, Ross McKercher (Foothills Medical Centre); David Sanders, Mark MacLeod, Abdel-Rahman Lawendy, Christina Tieszer (London Health Sciences Centre); David Stephen, Hans Kreder, Richard Jenkinson, Markku Nousiainen, Terry Axelrod, John Murnaghan, Diane Nam, Veronica Wadey, Albert Yee, Katrine Milner, Monica Kunz, Wesley Ghent (Sunnybrook Health Sciences Centre); Emil H. Schemitsch, Michael D. McKee, Jeremy A. Hall, Aaron Nauth, Henry Ahn, Daniel B. Whelan, Milena R. Vicente, Lisa M. Wild, Ryan M. Khan, Jennifer T. Hidy (St. Michael's Hospital); Chad Coles, Ross Leighton, Michael Biddulph, David Johnston, Mark Glazebrook, David Alexander, Catherine Coady, Michael Dunbar, J. David Amirault, Michael Gross, William Oxner, Gerald Reardon, C. Glen Richardson, J. Andrew Trenholm, Ivan Wong, Kelly Trask, Shelley MacDonald, Gwendolyn Dobbin (Queen Elizabeth II Health Sciences Centre); Ryan Bicknell, Jeff Yach, Davide Bardana, Gavin Wood, Mark Harrison, David Yen, Sue Lambert, Fiona Howells, Angela Ward (Human Mobility Research Centre, Queen's University and Kingston General Hospital); Paul Zalzal, Heather Brien, V. Naumetz, Brad Weening, Nicole Simunovic (Oakville Trafalgar Memorial Hospital); Eugene K. Wai, Steve Papp, Wade T. Gofton, Allen Liew, Stephen P. Kingwell, Garth Johnson, Joseph O'Neil, Darren M. Roffey, Vivian Borsella (The Ottawa Hospital); and Victoria Avram (Juravinski Hospital and Cancer Centre).
United States: Todd M. Oliver, Vicki Jones, Michelle Vogt (Boone Hospital Center—Columbia Orthopaedic Group); Clifford B. Jones, James R. Ringler, Terrence J. Endres, Debra L. Sietsema, Jane E. Walker (Orthopaedic Associates of Michigan); Kyle J. Jeray, J. Scott Broderick, David R. Goetz, Thomas B. Pace, Thomas M. Schaller, Scott E. Porter, Michael L. Beckish, John D. Adams, Benjamin B. Barden, Aaron T. Creek, Stephen H. Finley, Jonathan L. Foret, Garland K. Gudger Jr, Richard W. Gurich Jr, Austin D. Hill, Steven M. Hollenbeck, Lyle T. Jackson, Kevin K. Kruse III, Wesley G. Lackey, Justin W. Langan, Julia Lee, Lauren C. Leffler, Timothy J. Miller, R. Lee Murphy, Jr, Lawrence K. O'Malley II, Melissa E. Peters, Dustin M. Price, John A. Tanksley, Jr, Erick T. Torres, Dylan J. Watson, Scott T. Watson, Stephanie L. Tanner, Rebecca G. Snider, Lauren A. Nastoff, Shea A. Bielby, Robert J. Teasdall (Greenville Health System); Julie A. Switzer, Peter A. Cole, Sarah A. Anderson, Paul M. Lafferty, Mengnai Li, Thuan V. Ly, Scott B. Marston, Amy L. Foley, Sandy Vang, David M. Wright (Regions Hospital-University of Minnesota); Andrew J. Marcantonio, Michael S. H. Kain, Richard Iorio, Lawrence M. Specht, John F. Tilzey, Margaret J. Lobo, John S. Garfi (Lahey Hospital & Medical Center); Heather A. Vallier, Andrea Dolenc, Mary Breslin (MetroHealth Medical Center); Michael J. Prayson, Richard Laughlin, L. Joseph Rubino, Jedediah May, Geoffrey Ryan Rieser, Liz Dulaney-Cripe, Chris Gayton (Miami Valley Hospital); James Shaer, Tyson Schrickel, Barbara Hileman (St. Elizabeth Youngstown Hospital); John T. Gorczyca, Jonathan M. Gross, Catherine A. Humphrey, Stephen Kates, John P. Ketz, Krista Noble, Allison W. McIntyre, Kaili Pecorella (University of Rochester Medical Center); Craig A. Davis, Stuart Weinerman, Peter Weingarten, Philip Stull, Stephen Lindenbaum, Michael Hewitt, John Schwappach, Janell K. Baker, Tori Rutherford, Heike Newman, Shane Lieberman, Erin Finn, Kristin Robbins, Meghan Hurley, Lindsey Lyle, Khalis Mitchell, Kieran Browner, Erica Whatley, Krystal Payton, Christina Reeves (Colorado Orthopedic Consultants); Lisa K. Cannada, David E. Karges, Sarah A. Dawson (St. Louis University Hospital); Samir Mehta, John Esterhai, Jaimo Ahn, Derek Donegan, Annamarie D. Horan, Patrick J. Hesketh, Evan R. Bannister (University of Pennsylvania); Jonathan P. Keeve, Christopher G. Anderson, Michael D. McDonald, Jodi M. Hoffman (Northwest Orthopaedic Specialists); Ivan Tarkin, Peter Siska, Gary Gruen, Andrew Evans, Dana J. Farrell, James Irrgang, Arlene Luther (University of Pittsburgh Medical Center); William W. Cross III, Joseph R. Cass, Stephen A. Sems, Michael E. Torchia, Tyson Scrabeck (Mayo Clinic); Mark Jenkins, Jules Dumais, Amanda W. Romero (Texas Tech University Health Sciences Center—Lubbock); Carlos A. Sagebien, Mark S. Butler, James T. Monica, Patricia Seuffert (University Orthopaedic Associates, LLC); Joseph R. Hsu, Daniel Stinner, James Ficke, Michael Charlton, Matthew Napierala, Mary Fan (US Army Institute of Surgical Research); Paul Tornetta III, Chadi Tannoury, Hope Carlisle, Heather Silva (Boston University Medical Center); Michael Archdeacon, Ryan Finnan, Toan Le, John Wyrick, Shelley Hess (UC Health/University of Cincinnati Medical Center); Michael L. Brennan, Robert Probe, Evelyn Kile, Kelli Mills, Lydia Clipper, Michelle Yu, Katie Erwin (Scott and White Memorial Hospital); Daniel Horwitz, Kent Strohecker, Teresa K. Swenson (Geisinger Medical Center); Andrew H. Schmidt, Jerald R. Westberg (Hennepin County Medical Center); Kamran Aurang, Gary Zohman, Brett Peterson, Roger B. Huff (Kaiser Permanente); Joseph Baele, Timothy Weber, Matt Edison (OrthoIndy Trauma St. Vincent Trauma Center); Jessica Cooper McBeth (Santa Clara Valley Medical Center); Karl Shively, Janos P. Ertl, Brian Mullis, J. Andrew Parr, Ripley Worman, Valda Frizzell, Molly M. Moore (Indiana University—Eskenazi Health Services); Charles J. DePaolo, Rachel Alosky, Leslie E. Shell, Lynne Hampton, Stephanie Shepard, Tracy Nanney, Claudine Cuento (Mission Hospital Research Institute); Robert V. Cantu, Eric R. Henderson, Linda S. Eickhoff (Dartmouth-Hitchcock Medical Center); E. Mark Hammerberg, Philip Stahel, David Hak, Cyril Mauffrey, Corey Henderson, Hannah Gissel, Douglas Gibula (Denver Health and Hospital Authority); David P. Zamorano, Martin C. Tynan, Deeba Pourmand, Deanna Lawson (University of California Irvine Medical Center); Gregory J. Della Rocca, Brett D. Crist, Yvonne M. Murtha, Linda K. Anderson (University of Missouri Health Care); Colleen Linehan, Lindsey Pilling (Covenant Healthcare of Saginaw); Courtland G. Lewis, Stephanie Caminiti, Raymond J. Sullivan, Elizabeth Roper (Hartford Hospital); William Obremskey, Philip Kregor, Justin E. Richards, Kenya Stringfellow (Vanderbilt University Medical Center); and Michael P. Dohm, Abby Zellar (Western Slope Study Group).
The Netherlands: Michiel J. M. Segers, Jacco A. C. Zijl, Bart Verhoeven, Anke B. Smits, Jean Paul P. M. de Vries, Bram Fioole, Henk van der Hoeven, Evert B. M. Theunissen, Tammo S. de Vries Reilingh, Lonneke Govaert, Philippe Wittich, Maurits de Brauw, Jan Wille, Peter M. N. Y. M. Go, Ewan D. Ritchie, Ronald N. Wessel, Eric R. Hammacher (St. Antonius Ziekenhuis); Martin J. Heetveld, Gijs A. Visser, Heyn Stockmann, Rob Silvis, Jaap P. Snellen, Bram Rijbroek, Joris J. G. Scheepers, Erik G. J. Vermeulen, Michiel P. C. Siroen, Ronald Vuylsteke, Hans L. F. Brom, Herman Rijna (Kennemer Gasthuis); Piet A. R. de Rijcke, Cees L. Koppert, Steven E. Buijk, Richard P. R. Groenendijk, Imro Dawson, Geert W. M. Tetteroo, Milko M. M. Bruijninckx, Pascal G. Doornebosch, Eelco J. R. de Graaf (IJsselland Ziekenhuis); Maarten van der Elst, Carmen C. van der Pol, Martijne van 't Riet, Tom M. Karsten, Mark R. de Vries, Laurents P. S. Stassen, Niels W. L. Schep, G. Ben Schmidt, W. H. Hoffman (Reinier de Graaf Gasthuis); Rudolf W. Poolman, Maarten P. Simons, Frank H. W. M. van der Heijden, W. Jaap Willems, Frank R. A. J. de Meulemeester, Cor P. van der Hart, Kahn Turckan, Sebastiaan Festen, Frank de Nies, Robert Haverlag, Nico J. M. Out, Jan Bosma (Onze Lieve Vrouwe Gasthuis); Albert van Kampen, Jan Biert, Arie B. van Vugt, Michael J. R. Edwards, Taco J. Blokhuis, Jan Paul M. Frölke, Leo M. G. Geeraedts, Jean W. M. Gardeniers, Edward C. T. H. Tan, Lodewijk M. S. J. Poelhekke, Maarten C. de Waal Malefijt, Bart Schreurs (University Medical Center St. Radboud); Gert R. Roukema, Hong A. Josaputra, Paul Keller, Peter D. de Rooij, Hans Kuiken, Han Boxma, Berry I. Cleffken, Ronald Liem (Maasstad Ziekenhuis); Steven J. Rhemrev, Coks H. R. Bosman, Alexander de Mol van Otterloo, Jochem Hoogendoorn, Alexander C. de Vries, Sven A. G. Meylaerts (Medisch Centrum Haaglanden); Michiel H. J. Verhofstad, Joost Meijer, Teun van Egmond, Frank H. W. M. van der Heijden, Igor van der Brand (St. Elisabeth Ziekenhuis); Peter Patka, Martin G. Eversdijk, Rolf Peters, Dennis Den Hartog, Oscar J. F. Van Waes, Pim Oprel (Erasmus MC, University Medical Center Rotterdam); Harm M. van der Vis, Martin Campo, Ronald Verhagen, G. H. Robert Albers, Arthur W. Zurcher (Tergooi Ziekenhuizen); Rogier K. J. Simmermacher, Jeroen van Mulken, Karlijn van Wessem, Taco J. Blokhuis, Steven M. van Gaalen, Luke P. H. Leenen (University Medical Center Utrecht); Maarten W. G. A. Bronkhorst, Onno R. Guicherit (Bronovo Ziekenhuis); and J. Carel Goslings, Robert Haverlag, Kees Jan Ponsen (Academic Medical Center).
International: Mahesh Bhatia, Vinod Arora, Vivek Tyagi (RLB Hospital and Research Centre, India); Susan Liew, Harvinder Bedi, Ashley Carr, Hamish Curry, Andrew Chia, Steve Csongvay, Craig Donohue, Stephen Doig, Elton Edwards, Greg Etherington, Max Esser, Andrew Gong, Arvind Jain, Doug Li, Russell Miller, Ash Moaveni, Matthias Russ, Lu Ton, Otis Wang, Adam Dowrick, Zoe Murdoch, Claire Sage (The Alfred, Australia); Frede Frihagen, John Clarke-Jenssen, Geir Hjorthaug, Torben Ianssen, Asgeir Amundsen, Jan Egil Brattgjerd, Tor Borch, Berthe Bøe, Bernhard Flatøy, Sondre Hasselund, Knut Jørgen Haug, Kim Hemlock, Tor Magne Hoseth, Geir Jomaas, Thomas Kibsgård, Tarjei Lona, Gilbert Moatshe, Oliver Müller, Marius Molund, Tor Nicolaisen, Fredrik Nilsen, Jonas Rydinge, Morten Smedsrud, Are Stødle, Axel Trommer, Stein Ugland, Anders Karlsten, Guri Ekås, Elise Berg Vesterhus, Anne Christine Brekke (Oslo University Hospital, Norway); Ajay Gupta, Neeraj Jain, Farah Khan (Nirmal Hospital, India); Ateet Sharma, Amir Sanghavi, Mittal Trivedi (Satellite Orthopaedic Hospital and Research Centre, India); Anil Rai, Subash, Kamal Rai (Highway Hospital, India); Vineet Yadav, Sanjay Singh, Kamal Rai (Popular Hospital, India); Kevin Tetsworth, Geoff Donald, Patrick Weinrauch, Paul Pincus, Steven Yang, Brett Halliday, Trevor Gervais, Michael Holt, Annette Flynn (Royal Brisbane and Women's Hospital, Australia); Amal Shankar Prasad, Vimlesh Mishra (Madhuraj Nursing Home, India); D. C. Sundaresh, Angshuman Khanna (M. S. Rammaiah Medical College & Hospital, India); Joe Joseph Cherian, Davy J. Olakkengil, Gaurav Sharma (St John's Medical College Hospital, India); Marinis Pirpiris, David Love, Andrew Bucknill, Richard J. Farrugia (Royal Melbourne Hospital, Australia); Hans-Christoph Pape, Matthias Knobe, Roman Pfeifer (University of Aachen Medical Center, Germany); Peter Hull, Sophie Lewis, Simone Evans (Cambridge University Hospitals, England); Rajesh Nanda, Rajanikanth Logishetty, Sanjeev Anand, Carol Bowler (University Hospital of North Tees, England); Akhil Dadi, Naveen Palla, Utsav Ganguly (Sunshine Hospital, India); B. Sachidananda Rai, Janakiraman Rajakumar (Unity Health Complex, India); Andrew Jennings, Graham Chuter, Glynis Rose, Gillian Horner (University Hospital of North Durham and Darlington Memorial Hospital, England); Callum Clark, Kate Eke (Wexham Park Hospital, England); and Mike Reed, Dominic Inman, Chris Herriott, Christine Dobb (Northumbria Healthcare NHS Foundation Trust, England).
1. Parker M, Johansen A. Hip fracture. BMJ. 2006;333:27–30.
2. Zlowodzki M, Jönsson A, Paulke R, et al. Shortening after femoral neck fracture fixation: is there a solution? Clin Orthop Relat Res. 2007;461:213–218.
3. Zlowodzki M, Brink O, Switzer J, et al. The effect of shortening and varus collapse of the femoral neck on function after fixation of intracapsular fracture of the hip: a multi-centre cohort study. J Bone Joint Surg Br. 2008;90:1487–1494.
4. Zlowodzki M, Ayeni O, Ayieni O, et al. Femoral neck shortening after fracture fixation with multiple cancellous screws: incidence and effect on function. J Trauma. 2008;64:163–169.
5. Weil YA, Khoury A, Zuaiter I, et al. Femoral neck shortening and varus collapse after navigated fixation of intracapsular femoral neck fractures. J Orthop Trauma. 2012;26:19–23.
6. Zielinski SM, Keijsers NL, Praet SF, et al. Femoral neck shortening after internal fixation of a femoral neck fracture. Orthopedics. 2013;36:e849–e858.
7. Slobogean GP, Stockton DJ, Zeng BF, et al. Femoral neck shortening in adult patients under the age of 55 years is associated with worse functional outcomes: analysis of the prospective multi-center study of hip fracture outcomes in China (SHOC). Injury. 2017;48:1837–1842.
8. Stockton DJ, Lefaivre KA, Deakin DE, et al. Incidence, magnitude, and predictors of shortening in young femoral neck fractures. J Orthop Trauma. 2015;29:e293–e298.
9. FAITH Investigators. Fracture fixation in the operative management of hip fractures (FAITH): an international, multicentre, randomised controlled trial. Lancet. 2017;389:1519–1527.
10. Serrano R, Blair JA, Watson DT, et al. Cephalomedullary nail fixation of intertrochanteric femur fractures: are two proximal screws better than one? J Orthop Trauma. 2017;31:577–582.
11. Bellamy N. WOMAC Osteoarthritis Index: A User's Guide. London, ON: University of Western Ontario; 1995.
12. McConnell S, Kolopack P, Davis AM. The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC): a review of its utility and measurement properties. Arthritis Rheum. 2001;45:453–461.
13. Liu Y, Ai ZS, Shao J, et al. Femoral neck shortening after internal fixation. Acta Orthop Traumatol Turc. 2013;47:400–404.
14. Crosby JM, Parker MJ. Femoral neck collapse after internal fixation of an intracapsular hip fracture: does it indicate a poor outcome? Injury. 2016;47:2760–2763.
15. SooHoo NF, Li Z, Chenok KE, et al. Responsiveness of patient reported outcome measures in total joint arthroplasty patients. J Arthroplasty. 2015;30:176–191.
16. Aprato A, Massè A, Caranzano F, et al. Patient-perceived quality of life after total hip arthroplasty: elective versus traumatological surgery. ISRN Orthop. 2011;2011:910392.