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Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448DOI 10.1186/s12891-016-1302-6STUDY PROTOCOLOpen AccessOperative treatment of 2-part surgical neckfractures of the proximal humerus (AO 11-A3)in the elderly: Cement augmented lockingplate Philos vs. proximal humerus nailMultiLoc Tobias Helfen*, Georg Siebenbürger, Marcel Mayer, Wolfgang Böcker, Ben Ockert and Florian HaastersAbstractBackground: Proximal humeral fractures are with an incidence of 4–5 % the third most common fractures inthe elderly. In 20 % of humeral fractures there is an indication for surgical treatment according to the modifiedNeer-Criteria. A secondary varus dislocation of the head fragment and cutting-out are the most commoncomplications of angle stable locking plates in AO11-A3 fractures of the elderly. One possibility to increase thestability of the screw-bone-interface is the cement augmentation of the screw tips. A second is the use of amultiplanar angle stablentramedullary nail that might provide better biomechanical properties after fixation of2-part-fractures. A comparison of these two treatment options augmented locking plate versus multiplanar anglestable locking nail in 2-part surgical neck fractures of the proximal humerus has not been carried out up to now.Methods/Design: Forty patients (female/male, 60 years or female postmenopausal) with a 2-part-fracture of theproximal humerus (AO type 11-A3) will be randomized to either to augmented plate fixation group (PhilosAugment)or to multiplanar intramedullary nail group (MultiLoc). Outcome parameters are Disabilities of the Shoulder, Arm andHand-Score (DASH) Constant Score (CS), American Shoulder and Elbow Score (ASES), Oxford Shoulder Score (OSS),Range of motion (ROM) and Short Form 36 (SF-36) after 3 weeks, 6 weeks, 3 months, 6 months, 12 and 24 months.Discussion: Because of the lack of clinical studies that compare cement augmented locking plates with multiplanarhumeral nail systems after 2-part surgical neck fractures of the proximal humerus, the decision of surgical methodcurrently depends only on surgeons preference. Because only a randomized clinical trial (RCT) can sufficiently answerthe question if one treatment option provides advantages compared to the other method we are planning to performa RCT.Trial registration: Clinical Trial (NCT02609906), November 18, 2015, registered retrospectively.Keywords: Humeral head, Osteosynthesis, Plate, Nail, Osteoporosis* Correspondence: [email protected] of Trauma Surgery, Ludwig-Maximilians-University (LMU),Campus Innenstadt, Nußbaumstr. 20, D-80336 Munich, Germany The Author(s). 2016 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication o/1.0/) applies to the data made available in this article, unless otherwise stated.

Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448BackgroundProximal humeral fractures are with an incidence of 4–5 %the third most common fractures in the elderly [1]. Theseare the second most common upper-limb fracture afterdistal radial fractures [2, 3]. Sixty-five percent of all patientswith a proximal humeral fracture are older than 60 years[1]. Being aware of the demographic change there will evenbe an increase of incidence of these fractures. Kannus et al.showed an incidence of 298 per 100,000 in the at least80 years old patients in 2007 [4]. Palvanen et al. predict anincrease of incidence of 50 % until 2030 [1].Approximately 80 % of all humeral fractures are minimally or non-displaced and can be treated conservatively with a good functional result [5]. In 20 % ofhumeral fractures there is an indication for surgicaltreatment according to the modified Neer-Criteria [6].These criteria are fulfilled if there is an angulation of atleast 45 between fracture fragments, a displacement ofthe humeral shaft against the humeral head of at least1 cm or a dislocation of the greater tuberosity of at least5 mm [7]. Up to now there is no evidence for superiorityof any surgical treatment in literature [8]. At the momentthe most frequently used surgical technique for treatmentof proximal humeral fractures is the angle stable plate fixation. There are various publications concerning this topicpublished by our research group [9, 10]. In our 10-yearsresults a majority of patients showed excellent and good,but also 16 % showed unsatisfactory results after lockingplate fixation [10]. Main risk for poor outcome was revision surgery caused by secondary displacement (14 %)which is also confirmed by results of other studies [11].In a further study our research group could show thatthere is a higher risk for secondary displacement in 2part-fractures with a gross primary dislocation or alarge metaphyseal fracture zone (AO 11-A3), especiallyin osteoporotic patients [12]. Moreover these are common fractures and because of that a problem in surgicaltreatment.A secondary varus dislocation of the head fragmentand cutting-out are the most common complications ofangle stable locking plates in AO 11-A3 fractures of theelderly. The primary reason for this mechanism of failure is certain instability of transmetaphyseal fracturesin the region of the surgical neck caused by loss of impaction in a porous spongiosa. Because of that theforces on the head screws are high while the so calledscrew-bone-interface is rather weak after a surgicaltreatment.Currently there exist various approaches to avoid a failure of the primary screw implantation. One possibility toincrease the stability of the screw-bone-interface is the cement augmentation of the screw tips [13–18]. To datethere exists no clinical study that reports the results oflocking plate fixation and the augmentation of cannulatedPage 2 of 7head screws although it is a widely used method in everyday surgery, especially in the elderly.A second possibility to prevent secondary displacementafter surgical treatment of 2-part-fractures is the use of anintramedullary nails [19–22]. A further development ofintramedullary nails is multiplanar nailing. Screws can beinserted in various different levels and directions whichcan lead to a clearly higher stability [23–25].A comparison of these two treatment options augmented locking plate versus multiplanar angle stablelocking nail in 2-part surgical neck fractures of the proximal humerus has not been carried out up to now.Aim of the studyThis randomized clinical study aims to compare cementaugmented locking plate fixation versus a multiplanarhumeral nail system for the treatment of displaced 2part proximal humeral fractures in the elderly patient interms of complication rate, shoulder function, quality oflife and patient satisfaction.HypothesisWe anticipate the cement augmented angle stable platefixation system Philos with augmentation (DepuySynthes) achieves significant better outcome concerningintra- and postoperative complication and revision rate,functional outcome and patient satisfaction comparedwith the multiplanar proximal MultiLoc -Nail (DepuySynthes).Methods/DesignStudy designFor comparative evaluation of the two treatment options: cement augmented plate fixation versus multiplanar intramedullary locking nail in proximal humeralfractures (AO Type 11-A3) we planned a single-centreparallel group, randomized controlled trial (RCT), following the CONSORT statement guidelines [26].Forty patients will be randomized to either to augmented plate fixation group (PhilosAugment) or to multiplanar intramedullary nail group (MultiLoc). Patientswill be recruited at our hospital (level I trauma centre).All subjects must provide written informed consent.Population, screening and randomizationThe study will be conducted at the Department of TraumaSurgery, University of Munich (LMU), Germany. Patientswill be screened within the regular emergency unit settings using the AO-Classification. Patients (female/male, 60 years or female postmenopausal) with a 2-partsurgical neck fractures of the proximal humerus (AO type11-A3). A correct fracture classification is ensured by CTscans for all participants. Inclusion and exclusion criteriaare listed in Table 1. Within 7 days, participants must be

Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448Page 3 of 7Table 1 Inclusion- and exclusion criteriaInclusion criteriaExclusion criteria Age: 60 years, or female postmenopausal 2-part fracture according to AO-classification(Arbeitsgemeinschaft für Osteosynthesefragen):AO 11-A3 Signed informed consent Patient can read and understand German Refusal to participate in the study Not Independent Dementia and/or institutionalized Does not understand written and spoken guidance German Pathologic fracture or a previous fracture of the same proximal humerus Alcoholism or drug addiction, e.g., in the emergency department, breathalyzerindicates blood alcohol concentration of more than 2 % Other injury to the same upper limb requiring surgery Major nerve injury (e.g., complete radial- or axillary nerve palsy) Rotator cuff tear arthropathy Open fracture Multi-trauma or -fractured patient Fracture dislocation or head-splitting fracture Non-displaced fracture Isolated fracture of the major or minor tubercle Any medical condition that excludes surgical treatment Pregnancyincluded. Inclusion and exclusion criteria are listed inTable 1. Within 7 days, participants must be included andrandomized by sealed envelope (opaque, not resealable)drawing (Fig. 1). Each subject will have a unique identification number and keep that number throughout the study.Sequence generation was performed by online StatisticalComputing Web Programme: www.randomization.com.InterventionsAll fractures will initially be immobilised by a Gilchristbandage. This is the same procedure as for patients whodo not attend this or any other trial and will be performed by the doctor on-duty in the emergency room.Patients will be admitted to the trauma ward after that.On the same day or at the latest on day after this patients will be informed about the current investigation,screened, included and randomized by one of the studyinvestigators to our trial after written consent will be obtained as described above. The patients are allowed tomake their decision within 24 h.Operative treatment is exclusively performed by thebelow mentioned study investigators. The interventiongroup will be treated by the angle stable 3-hole platefixation system Philos with augmentation (DepuySynthes) the comparison group by the multiplanarproximal humeral nail MultiLoc with the length of160 mm and a diameter according to the humeral shaft((Depuy-Synthes). For plate fixation screws are set in astandardized fashion: Seven screws placed subcorticalin row A, B, D and F as well as 3 screws bicortical inthe shaft (one proximal non-locking and two distallocking screws). Whenever possible (according to contrastdye testing) the screws in row A and E are augmentedwith 0.5 ml Traumacem V (Depuy-Synthes). Alternatively screws in row B and D are used. The MultiLok nailis standardized fixed with three 4.5 mm MultiLoc screwsat levels A, B and D. Two additional 3.5 mm screw-in-screws are used at levels A and B and aimed posteriorly.In the shaft one ascending calcar screw and two multiplanar distal locking screws are implanted. All study investigators are very experienced with both devices and havecompleted their learning curves.Types of outcomes and follow-upThe primary outcome will be the Disabilities of the Shoulder, Arm and Hand (DASH) Score after 24 months. Thesecondary outcome parameters are listed in Table 2 (Disabilities of the Shoulder, Arm and Hand-Score (DASH),Constant Score (CS), American Shoulder and Elbow Score(ASES), Oxford Shoulder Score (OSS), Range of motion(ROM) and Short Form 36 (SF-36) after 3 weeks, 6 weeks,3 months, 6 months, 12 and 24 months. Further evaluation will be: Fracture reduction and healing results(radiographic findings), complications (Table 3) andrevisions. Complications will be classified as described inTable 2. Follow-up examinations will take place after3 weeks, 6 weeks, 3 months, 6 months, 12 and 24 months(Fig. 1). There will be no blinding of outcome assessment(Table 2).Sample size estimation and statistical analysisPrimary outcome of our study is the DASH-Score (0–100points, 0 (no disability) to 100 (most severe disability))[27]. In a case number calculation for unpaired samplesand target figures we assume an effect size of a differenceof 15 points at the highest as there is a standard deviationof 15 points as well. A difference of 15 points is seen as aminimal clinically important difference. This data hasbeen published in other studies before. It has been testedfor plausibility and has been taken over after that. Following parameters are the results: Delta 15, SD 15, alpha 0.05, power 0.8. N 40 patients will be included according to the above mentioned calculation. To protect

Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448Page 4 of 7Fig. 1 Randomization and follow-up workflowthe quality of our study the drop-out rate should not exceed 20 % (e.g. 3 patients per group).Standard deviations or confidence intervals, in the caseof percentages, will be provided for each type of epidemiological data. The assumption of normality will beverified by the Shapiro-Wilk test for the use of parametric tests. A Pearson’s chi-square test will be employed toanalyse results from the two groups involving categoricalvariables. A Student’s (parametric) t-test will be used forcomparing groups of numeric variables. Paired t-tests(parametric) and Wilcoxon tests (non-parametric) willbe used to compare clinical progression at follow-up intervals. The significance level used in all statistical testsis to be 5 % (alpha 0.05), with tests having a P valueless than 0.05 being statistically significant.Should differences be found in primary outcomes,then statistical methods will be used to test whetherthere is robust correlation between epidemiological factors or fracture seriousness and the observed functionaloutcomes. In addition, we intend to employ KaplanMeier survival analysis to evaluate drop-outs shouldhigh rates of complications (greater than 20 %) occur ineither assignment group.Patients who experience treatment failures and requireadditional surgery will be monitored and their resultscomputed in the primary assignment group (intention-

Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448Page 5 of 7Table 2 Assessment and procedure of the trialAssessmentPre-operative1. visit 6 weeks2. visit 3 months3. visit 6 months4. visit 12 months5. visit 24 monthsDoctor’s visitXXXXXXx-ray (true a.p., lateral, axial view)XXXXXXCT-scanXInclusion criteriaXConsentXMedical -36XXXXXXXUltrasound for rotator cuff statusROM range of motion, CS Constant Score, ASES American Shoulder and Elbow Score, OSS Oxford Shoulder Score, DASH Disabilities of the Shoulder, Arm and Hand,SF-36 Score and Short Form 36to-treat principle). Provisions are to be made for blindedstatistical analysis of data by a statistician who is unfamiliar with the objectives and outcomes of interest.Table 3 ComplicationsClassification of complicationsA) Implant associated complications/revisionsA1) varus displacementA2) dorsal displacemenmtA3) varus and dorsal displacementA1-3) S additional screw-cut-outA4) humeral shaft perforationA5) implant breakingA6) subacromial impingementA7) intraarticular cement malpositionB) Non-implant associated complications/revisionsB1) frozen shoulderB2) hematoma/seromaB3) infectionB4) impairment of wound healingB5) nerve injuryB6) avascular necrosisC) Technical complications/revisionsC1) malposition of the implantC2) inadequate reductionD) Medical complicationsD1) venous thrombembolismsD2) pulmonary complicationsD3) cardiac complicationsDiscussionThe present study protocol on the operative treatmentof 2-part surgical neck fractures (AO 11-A3) of theproximal humerus in the elderly is the first study tocompare a cement augmented locking plate versus amultiplanar proximal humerus nail. Both options mightprevent secondary displacement after surgical treatmentof 2-part-fractures.Since secondary dislocation of the humeral head is stillthe most common complication after surgical treatmentof proximal humeral fractures [10] various approachesexist to increase the biomechanical properties of theavailable constructs. One option is to increase the stability of the screw-bone-interface in locking plate devicesby cement augmentation of the screw tips. Thereforecannulated screws are introduced in the humeral headand a small amount of Polymethylmethacrylat cement(PMMA) is injected around the screw tip. Various biomechanical trials demonstrate that the cement augmentation causes a noticeably higher primary stability. Ungeret al. showed a significantly higher tolerance concerningvarus-bending and axial-rotation after augmentation ofthe four most proximal screws [13]. Roderer et al. alsoachieved almost the same results concerning primarystability of the fracture by positioning of only two augmented screws in the region of the least bone density[15, 28]. Krappinger et al. recommended screw tip augmentation after studying predictors for failure of surgicalfixation in proximal humerus fractures. They especiallypointed out a reduced bone density as a main risk factor

Helfen et al. BMC Musculoskeletal Disorders (2016) 17:448for failure of primary fixation [16]. Although screw tpaugmentation is widely used, there is no study reportingon clinical results.In a clinical retrospective study of 2- and 3-partfractures in older patients (age: 60–83 years) Mihara et al.reported good results in terms of function, range of motion (ROM), pain and alignment of the former fracture elements after a mean follow-up of 14 months aftertreatment by nail [19]. A biomechanical trial by Furoria etal. resulted in higher rotational stability and toleranceagainst torsion after locking plate fixation compared to anintramedullary nail, whereas there was no significant difference in movement of the fracture elements [20]. Similarresults were observed in a biomechanical study byEdwards et al. who found a significant stiffer boneimplant construct after usage of a proximal humeral nailcompared to a locking compression plate [21]. Lekic et al.showed in a clinical study a comparable outcome aftertreatment of 2-part- fractures with intramedullary nail(IMN) and locking plate but assume a higher rate of complication after use of a nail [22]. A further development ofIMNs is multiplanar nailing. Screws can be inserted invarious different levels and directions (multiplanar) whichcan lead to less implant toggling and higher stability [23].Using angle stable locking screws in the distal part of thehumerus results in a significant lower movement of thefracture elements during rotational and bending load,especially in a postoperative early stage [24]. In a randomized controlled trial Zhu et al. compared the IMN withthe non-augmented locking plate in 2-part surgical neckfractures of the proximal humerus and showed a lowercomplication rate in the IMN group whereas the outcomein the locking plate group was better. After three years nodifference in the outcome measured by the ASES-Scorewas observed [25].Respecting the increasing incidence of fragility fractures to the proximal humerus, there is an urgent needto optimize the stability of our fixation construct. Withthis RCT we aim to compare the clinical outcome of thelatest implant designs addressing this