Transverse Fractures of the Femoral Shaft Are a Better Predictor of Nonaccidental Trauma in Young Children Than Spiral Fractures Are

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1 106 COPYRIGHT Ó 2015 BY THE JOURNAL OF BONE AND JOINT SURGERY, INCORPORATED Transverse Fractures of the Femoral Shaft Are a Better Preictor of Nonacciental Trauma in Young Chilren Than Spiral Fractures Are Ryan Murphy, BS, Derek M. Kelly, MD, Alice Moisan, BSN, Norfleet B. Thompson, MD, William C. Warner Jr., MD, James H. Beaty, MD, an Jeffrey R. Sawyer, MD Investigation performe at the Campbell Clinic, University of Tennessee, an Le Bonheur Chilren s Hospital, Memphis, Tennessee Backgroun: Certain fracture configurations, especially spiral fractures, are often thought to be inicative of nonacciental trauma in chilren. The purpose of this stuy was to etermine whether femoral fracture morphology, as etermine by an objective measurement (fracture ratio), was inicative of nonacciental trauma in young chilren. Methos: Consecutive patients who were three years of age or younger an ha a close, isolate femoral shaft fracture treate at an urban peiatric level-i trauma center between 2005 an 2013 were ientifie. Anteroposterior an lateral fracture ratios (fracture length/bone iameter) were calculate for each patient by a fellowship-traine peiatric orthopaeic surgeon who was bline to the patient s clinical history. The presence or absence of a Chil Protective Services referral as well as institutional Chil Assessment Program evaluations were reviewe. Nonacciental trauma was eeme to be present, absent, or ineterminate by Chil Protective Services or an on-site Chil Assessment Program team. To further evaluate an quantify the likelihoo of nonacciental trauma, the criteria of the Moifie Maltreatment Classification System were use. Results: Of 122 patients ientifie, ninety-five met the inclusion criteria for this stuy. Of these ninety-five, fifty-one (54%) ha either a Chil Protective Services or a Chil Assessment Program consultation because of suspecte nonacciental trauma. Thirteen (25%) were foun to have nonacciental trauma as etermine by Chil Protective Services or the Chil Assessment Program team an seven (14%) ha ineterminate Chil Protective Services or Chil Assessment Program investigations. All thirteen patients with nonacciental trauma, as well as the seven patients with an ineterminate Chil Protective Services or Chil Assessment Program investigation, ha positive Moifie Maltreatment Classification System scores for physical abuse. Patients who ha nonacciental trauma ha significantly ecrease mean anteroposterior fracture ratios compare with those who ha confirme acciental trauma (p < ). Conclusions: The fracture ratio can be helpful to etermine fracture morphology an can be use as part of the assessment of a chil with suspecte nonacciental trauma. While not iagnostic, the presence of a transverse iaphyseal femoral fracture in a young chil shoul raise the inex of suspicion for nonacciental trauma. Level of Evience: Prognostic Level III. See Instructions for Authors for a complete escription of levels of evience. Peer Review: This article was reviewe by the Eitor-in-Chief an one Deputy Eitor, an it unerwent bline review by two or more outsie experts. The Deputy Eitor reviewe each revision of the article, an it unerwent a final review by the Eitor-in-Chief prior to publication. Final corrections an clarifications occurreuring one or more exchanges between the author(s) an copyeitors. Musculoskeletal injuries are the secon most common physical manifestation of nonacciental trauma (NAT) in chilren, after soft-tissue injuries 1. It is estimate that 10% to 70% of chilren with NAT have a musculoskeletal injury, an 30% to 50% of all abuse chilren are seen by an orthopaeic surgeon 2-4. Certain fractures of the ribs, corner Disclosure: None of the authors receive payments or services, either irectly or inirectly (i.e., via his or her institution), from a thir party in support of any aspect of this work. None of the authors, or their institution(s), have ha any financial relationship, in the thirty-six months prior to submission of this work, with any entity in the biomeical arena that coul be perceive to influence or have the potential to influence what is written in this work. Also, no author has ha any other relationships, or has engage in any other activities, that coul be perceive to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitte by authors are always provie with the online version of the article. J Bone Joint Surg Am. 2015;97:

2 107 fractures, long-bone fractures in nonambulatory chilren, an multiple fractures at ifferent stages of healing are generally suggestive of NAT 2. Particular morphologic features of the fracture, such as a spiral configuration, have been suggeste to be associate with a higher likelihoo of NAT 5. Balwin an Scherl recently state that fracture morphology can inicate the irection but not the etiology of the mechanical force causing the injury 2. Ientifying NAT relies on a combination of thorough history review, physical examination, an raiographic stuies, an it often requires a multiisciplinary approach 3,6. Along with characterization of maltreatment by Chil Protective Services (CPS), injury assessment tools, such as the Moifie Maltreatment Classification System (MMCS) 5,7-9,havebeenevelopeto help to ientify the presence an quantify the severity of NAT. A recent stuy at our institution foun substantial variability in escribing femoral shaft fractures in young chilren 10. A fracture ratio, which is calculate by iviing the maximum length of the fracture by the iameter of the bone at the fracture site (Fig. 1), was evelope to more objectively etermine fracture morphology. Fractures with lower ratios (closer to 1) are more transverse, an those with higher ratios are more spiral. Intraobserver reliability with this ratio was goo for orthopaeic surgeons (kappa, 0.6), an overall interobserver agreement was 70%, regarless of specialty, for transverse fractures when the fracture ratio was <1.47 an for spiral fractures when the fracture ratio was >3.45. The purpose of this stuy was to etermine whether fracture morphology, as etermine with use of the fracture ratio, is inicative of NAT in young chilren with a femoral shaft fracture. Materials an Methos After institutional review boar approval was obtaine, consecutive patients who were three years of age or younger an ha a close, isolate femoral shaft fracture treate at an urban peiatric level-i trauma center between 2005 an 2013 were ientifie with use of an International Classification of Diseases, Ninth Revision (ICD-9) coe (821.01). Patients were inclue only if appropriate anteroposterior an lateral raiographs were mae at the time of initial presentation an complete meical recors were available. Patients with metabolic bone isease, neuromuscular isorers, genetic conitions such as osteogenesis imperfecta, or other ocumente reasons for osteopenia were exclue. Anteroposterior an lateral fracture ratios were calculate for each patient by a fellowship-traine peiatric orthopaeic surgeon eucate in the fracture-ratio calculations an bline to the clinical history (J.R.S.). The presence or absence of a CPS referral, which coul be mae by any health-care professional at the institution, as well as institutional Chil Assessment Program (CAP) evaluations, were reviewe. The fracture ratio was not calculate or use by members of the CPS or CAP team. Chil abuse was eeme to be present, absent, or ineterminate by CPS an/or an on-site CAP team, which was le by a single experience peiatrician with specialize training in ientifying NAT in chilren. To further evaluate an quantify the likelihoo of NAT, the MMCS criteria for nonescript physical abuse (section 109), violent hanling of a chil (section 105), an a hit or kick to limbs or extremities (section 104) were use, an they provie a measurement of maltreatment severity on a scale of 1 to 6 9. The MMCS score is not part of a routine NAT evaluation at our institution an was calculate inepenently by a single investigator. The finings of CPS investigations were eeme to be NAT if abuse was explicitly note in the CPS or CAP report or if there was sufficient evience to remove the chil from the caretaker s custoy or take legal action against those suspecte of chil abuse. The finings of CPS investigations were efine as ineterminate if the cases were suspicious for NAT but the cause coul not be etermine an the chilren were release back into the caretaker s custoy; either the event happene outsie of the caretaker s watch (e.g., at aycare or with a babysitter) or no action was taken against the caretaker because of a lack of evience. All groups were analyze with use of D Agostino-Pearson omnibus tests for normality an F-tests to compare variances. Also, subsequent unpaire t-test analyses of fracture ratios were performe accoringly. Source of Funing No external funing was receive. Fig. 1 The fracture ratio was etermine by measuring the length of the fracture (Line 1) aniviing it by the iameter of the bone (Line 2). (Reprouce, with permission of Wolters Kluwer Health, Lippincott Williams & Wilkins, from Thompson NB, Kelly DM, Warner WC Jr, Rush JK, Moisan A, Hanna WR Jr, Beaty JH, Spence DD, Sawyer JR. Intraobserver an interobserver reliability an the role of fracture morphology in classifying femoral shaft fractures in young chilren. J Peiatr Orthop. 2014;34:352-8.) Results Of 122 patients ientifie, 102 (84%) ha complete recors for review an met the other inclusion criteria for this stuy. Of these 102, seven (7%) were exclue because of metabolic bone isease or osteopenia, which left ninety-five patients (93%) for analysis. The sixty-five males (mean age, 21.8 months) an thirty females (mean age, 20.7 months) ha an average age of 21.5 months.

3 108 (Fig. 2-B). The 95% confience intervals (CIs) for the anteroposterior fracture ratios were 1.06 to 2.01 for NAT an 2.48 to 3.08 for acciental trauma. The 95% CIs for the lateral fracture ratios were 1.18 to 2.31 for NAT an 2.72 to 3.44 for acciental trauma. The mean age was 16.8 months for patients with NAT an 21.9 months for those with acciental trauma (p = 0.17). Fig. 2-A NAT Compare with Possible NAT Patients who ha NAT ha significantly ecrease mean anteroposterior fracture ratios compare with those who ha possible NAT (1.53 compare with 2.56; p = ) (Fig. 3-A). Similar finings were note with use of the lateral fracture ratio (1.75 compare with 3.05; p = ) (Fig. 3-B). The 95% CIs for the anteroposterior fracture ratios were 1.06 to 2.01 for NAT an2.05to3.07forpossiblenat.the95%cisforthelateral fracture ratios were 1.18 to 2.31 for NAT an 2.45 to 3.64 for possible NAT. The mean age was 16.8 months for patients with NAT an 21.1 months for those with possible NAT (p = 0.28). Fig. 2-B Figs. 2-A an 2-B Graphs showing anteroposterior (AP; Fig. 2-A) an lateral (Fig. 2-B) femoral fracture ratios of seventy-five patients who ha confirme acciental trauma compare with thirteen patients who ha confirme nonacciental trauma (NAT). The ratios were significantly ifferent (p < for anteroposterior femoral fractures an p = for lateral femoral fractures). The blue line inicates the mean, an the re I-bar inicates the 95% confience interval. Fig. 3-A Of these ninety-five patients, fifty-one (54%) ha either a CPS or CAP consultation because of suspecte NAT. Forty-four chilren i not have a CPS or CAP evaluation: twenty-eight ha acciental trauma witnesse by parents or caretakers, five were injure when their caretakers fell while holing them, five were involve in motor vehicle accients, an six ha no cause ocumente in their recors but never were referre for a CPS or CAP evaluation. Thirteen (25%) of the fifty-one chilren with a CPS or CAP consultation ha NAT, an seven (14%) ha CPS investigations with ineterminate finings. All thirteen patients with NAT an the seven patients with ineterminate CPS finings ha positive MMCS scores for physical abuse. NAT Compare with Acciental Trauma Patients who ha NAT ha significantly ecrease mean anteroposterior fracture ratios compare with those who ha acciental trauma (1.53 compare with 2.78; p < ) (Table I an Fig. 2-A). Similar finings were note with use of the lateral fracture ratio (1.75 compare with 3.08; p = ) Fig. 3-B Figs. 3-A an 3-B Anteroposterior (AP; Fig. 3-A) an lateral (Fig. 3-B) femoral fracture ratios for all patients who haefinitive investigations by Chil Protective Services (CPS). The trauma was rule acciental in thirty-one patients an nonacciental in thirteen. The ratios were significantly ifferent (p = for anteroposterior femoral fractures an p = for lateral femoral fractures). The blue line inicates the mean, an the re I-bar inicates the 95% confience interval.

4 109 TABLE I Comparison of Fracture Ratios Between Acciental an Nonacciental Trauma Groups* Comparison Fracture Ratio Acciental NAT P Value Acciental (n = 75) an NAT (n = 13) Anteroposterior <0.001 Lateral CPS evaluate: acciental (n = 31) an NAT (n = 13) Anteroposterior Lateral Acciental (n = 75) an positive MMCS (n = 20) Anteroposterior Lateral < *NAT = nonacciental trauma, CPS = Chil Protective Services, an MMCS = Moifie Maltreatment Classification System. Positive MMCS Coing Compare with Acciental Trauma Patients who ha positive MMCS coing ha significantly ecrease mean anteroposterior fracture ratios compare with Fig. 4-A Fig. 4-B Figs. 4-A an 4-B Anteroposterior (AP; Fig. 4-A) an lateral (Fig. 4-B) femoral fractures ratios of seventy-five patients who ha confirme acciental trauma (either never requiring a Chil Protective Services [CPS] consultation or etermine acciental by CPS) compare with twenty patients who ha positive Moifie Maltreatment Classification System (MMCS) coing (incluing all thirteen patients who ha confirme nonacciental trauma [NAT] an the seven patients who ha ineterminate CPS finings). The blue line inicates the mean, an the re I-bar inicates the 95% confience interval. those who ha acciental trauma (1.91 compare with 2.78; p = ) (Fig. 4-A). Similar finings were note with use of the lateral fracture ratio (1.87 compare with 3.08; p < ) (Fig 4-B). The 95% CIs for the anteroposterior fracture ratios were 1.37 to 2.41 for patients with positive MMCS coing an 2.48 to 3.08 for patients with acciental trauma. The range of the lateral fracture ratios was 1.44 to 2.30 for positive MMCS coing an 2.72 to 3.44 for acciental trauma. The mean age was 20.0 months for patients with a positive MMCS an 21.9 months for patients with acciental trauma (p = 0.559). Discussion Because of the frequency of musculoskeletal injury in chilren who sustain NAT, orthopaeic surgeons often are involve in their care. Certain fractures have a high likelihoo of an abusive etiology, incluing metaphyseal corner fractures, posterior fractures of the ribs, an long-bone fractures in nonambulatory chilren, as well as bilateral long-bone fractures or multiple fractures at ifferent stages of healing 2,11,12. While fracture morphology can yiel information regaring the mechanism of injury (such as a spiral fracture cause by a rotational force or a corner fracture cause by a traction force), it gives no information on the etiology of the force 2. Spiral fractures have been consiere inicative of NAT because of the belief that the twisting mechanism require to create them oes not occur in acciental trauma in young chilren Despite these unique fracture patterns, King et al. reporte that, in their review of 429 fractures in 189 battere chilren, the mostcommonfracturewasanacutetransverseiaphysealfracture; these transverse fractures occurre most often in the humerus, followe by the tibia an femur 21.Similarfinings were note in an injury-plausibility stuy by Pierce et al., in which transverse fractures were more suspicious for NAT than spiral fractures were 22. While the authors of both stuies foun transverse fractures to be more commonly associate with NAT than spiral fractures were, no raiographic efinition or quantification of a spiral or transverse fracture was use. Despite the finings of these an other stuies, the perception remains, base on oler stuies, that spiral femoral fractures are suggestive of NAT 19,23,24. We foun that the use of a stanarize raiographic measure, the fracture ratio, to classify femoral shaft fractures as

5 110 transverse, spiral, or oblique prouce moerate interobserver agreement (kappa, 0.48) among peiatric orthopaeic surgeons, emergency room physicians, an musculoskeletal raiologists. Peiatric orthopaeic surgeons ha slightly higher interobserver agreement (kappa, 0.54) than the other two groups i, an this group also ha strong intraobserver agreement (kappa, 0.71). While there was consierable variability in classifying fractures as oblique, there was goo interobserver agreement in classifying fractures as transverse with lower fracture ratios (<1.47) an as spiral with higher fracture ratios (>3.45). A single peiatric orthopaeic surgeon traine in this technique (J.R.S.) quantifie the morphologic features of the fractures. Significant ifferences in fracture morphology were foun between NAT an acciental trauma (p < ); NAT was associate more frequently with transverse fractures. Even when all patients who were referre to CPS an/or CAP with enough evience of NAT to warrant referral were evaluate, this relationship remaine. This comparison is clinically relevant because it may be the most ifficult group in which to make the iagnosis of NAT or acciental trauma. In aition, we were able to correct for any potential bias in our institution s CPS referral an/or CAP evaluations. We also stratifie these patients in terms of a well-establishe, valiate chil-abuse scale, the MMCS. Moreover, the fact that we were unable in any comparison to fin a relationship between NAT an spiral fracture morphology lens further evience to the growing boy of knowlege that spiral femoral fractures generally are not associate with NAT in chilren. One potential limiting factor in this stuy is that we report the experience of a single institution, an the inications for CPS referral may iffer among centers. At our high-volume urban peiatric level-i trauma center, any health-care professional can make a CPS referral, as is common nationwie. Because of the subjective nature of the iagnosis of NAT, it is possible that the criteria for a positive CAP evaluation may vary accoring to the members of the team at each institution. At our center, all evaluations were mae by a single experience peiatrician whose full-time practice is evote to the ientification an treatment of NAT. That transverse femoral fractures were more prevalent in the chilren who screene positive or ha an ineterminate case accoring to their MMCS score supports the finings of the CAP team. It is possible that aitional chilren with NAT might have been ientifie ha every chil in the stuy been evaluate by CPS. However, the experience an expertise of the staff at this level-i peiatric trauma center make it unlikely that a referral was not mae for any chil with any suggestion of NAT. Another potential limitation is that we inclue chilren up to the age of three years (olest patient, thirty-four months). While up to 50% of fractures in chilren less than one year of age are cause by NAT, the rate ecreases ramatically with age 4,22,25. Schwen et al. foun that the prevalence of NAT in ambulatory chilren with a femoral shaft fracture was 2.6% 12.Inourstuy, we were unable to fin any inepenent effect of age on the frequency of NAT. In aition, even if NAT is rare in ambulatory chilren, a careful assessment still nees to be mae because of the extremely high rate of reinjury if NAT is misse 26.Interestingly, Panya et al. foun that an age of more than eighteen months was an inepenent preictor of a humeral shaft fracture being a result of NAT, unlike femoral shaft fracture 27. Ientification of NAT remains challenging because of the subjective nature of many of the assessments use. The lack of a single objective test, except for rare vieotape examples, can lea to either a misseiagnosis 28,29 or a misiagnosis 12 of NAT. Even though we foun a strong association between the fracture ratio an positive MMCS scores an the iagnosis of NAT, there is enough variability in both the measurement of the fracture ratio an the finings in this stuy that the fracture ratio shoul not be use in isolation but as part of a comprehensive, iniviualize multiisciplinary assessment of NAT in a young chil with a femoral shaft fracture. Our finings o give further evience that there is no relationship between a spiral femoral fracture an the iagnosis of NAT an that, while not iagnostic, the presence of a transverse iaphyseal femoral fracture in a young chil shoul raise suspicion for NAT. n Ryan Murphy, BS Derek M. Kelly, MD Norfleet B. Thompson, MD William C. Warner Jr., MD James H. Beaty, MD Jeffrey R. Sawyer, MD Department of Orthopaeic Surgery an Biomeical Engineering, University of Tennessee, 1211 Union Avenue, Suite 510, Memphis, TN aress for J.R. Sawyer: jsawyer@campbellclinic.com Alice Moisan, BSN Le Bonheur Chilren s Hospital, 848 Aams Avenue, Memphis, TN References 1. McMahon P, Grossman W, Gaffney M, Stanitski C. Soft-tissue injury as an inication of chil abuse. J Bone Joint Surg Am Aug;77(8): Balwin KD, Scherl SA. Orthopaeic aspects of chil abuse. Instr Course Lect. 2013;62: Sink EL, Hyman JE, Matheny T, Georgopoulos G, Kleinman P. Chil abuse: the role of the orthopaeic surgeon in nonacciental trauma. Clin Orthop Relat Res Mar;469(3): Panya NK, Balwin K, Wolfgruber H, Christian CW, Drummon DS, Hosalkar HS. Chil abuse an orthopaeic injury patterns: analysis at a level I peiatric trauma center. J Peiatr Orthop Sep;29(6): Barber I, Perez-Rossello JM, Wilson CR, Silvera MV, Kleinman PK. Prevalence an relevance of peiatric spinal fractures in suspecte chil abuse. 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