TITLE: Effect of cement augmentation on early postoperative ADL score in patients treated with cephalomedullary nailing for trochanteric fractures
AUTHORS: Yusuke Mochizuki, Norio Yamamoto, Tatsuya Fujii, Tomoyuki Noda, Toshifumi Ozaki

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<div class = "text-blocks"><div class = "text-block"><span style = "font-weight:bold;">Introduction </span></div><div class = "text-block">Femoral trochanteric fractures are among the most frequently encountered fractures in clinical practice, and the number of these fractures continues to increase owing to an aging society [1,2]. As the average patient age increases, many cases get complicated by severe osteoporosis [1,2]. The most common mechanical complication related to trochanteric fracture fixation with cephalomedullary nails (CMNs) is cut-out [3]. Screw cut-out and cut-through is reported to occur in up to 16.5% of cases and lead to fixation failure [4].  </div><div class = "text-block">   In several biomechanical studies, improvements in stability have been demonstrated with cement augmentation devices [5,6]. Therefore, fixation with CMNs and cement augmentation (CA) has been developed as a new treatment option for osteosynthesis of trochanteric fractures in osteoporotic bones. Procedures with CA reportedly have good short-term postoperative clinical results, including a lower implant failure rate [7-9]. Based on previous studies comparing hip fractures with and without CA, no significant differences were found in the results at 3 months after surgery in terms of mortality and intraoperative healing position [7].  However, postoperative pain and the activities of daily living (ADL) score in the CA group were better than that in the group without CA at 6 weeks after surgery [10]. Notwithstanding, the effect on ADL in the early postoperative period has not yet been investigated despite the importance of early ADL performance in reducing postoperative complications and regaining ambulation after surgery [11].</div><div class = "text-block">   Therefore the purpose of this study is to clarify the effect of CA on early postoperative ADL scores in patients with trochanteric fractures. We hypothesize that the enhanced stability with CA will reduce loading pain, allowing patients to regain preoperative ADL in the early postoperative period and reduce perioperative complications.</div><div class = "text-block"><span style = "font-weight:bold;">Materials and Methods</span></div><div class = "text-block">Study design and setting</div><div class = "text-block">We will perform a prospective multicenter cohort study of patients with trochanteric fractures from February 2021, treated by 2 orthopedic surgeons from general hospitals in Japan. We designed the study in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) criteria and will use the checklist for reporting purposes [12].</div><div class = "text-block">Details of the research design includes:</div><div class = "text-block">P (population of interest): Patients undergoing internal fixation with CMN for trochanteric fracture</div><div class = "text-block">I (intervention): Fixation with CMN plus CA</div><div class = "text-block">C (control): Fixation with CMN only</div><div class = "text-block">O (outcomes): Cumulated ambulation score (CAS) (representing ADL in the early postoperative period), pain scale, and adverse events.</div><div class = "text-block">Patient selection</div><div class = "text-block">The inclusion criteria are patients with first-time trochanteric fractures (fracture type: AO Foundation/Orthopedic Trauma Association [AO/OTA] classification 31A [13]), age >60 years and ability to walk independently before the injury (walking without aid or with a cane or walker). The exclusion criteria are pathological fractures, open fractures, use of a wheelchair before the injury, history of allergy to cement, multiple lower extremity trauma, postoperative inability to bear weight, and postoperative medical complications making it difficult to leave the bed (pneumonia, heart failure, etc.). </div><div class = "text-block">Surgical procedures</div><div class = "text-block">First, we will perform a closed reduction on a traction table under fluoroscopic guidance. When we are not able to achieve adequate fracture reduction, we will add the procedures to achieve anteromedial cortical reduction via a lag screw incision or an additional mini-open anterolateral incision. [14]. We will then fix the fracture with a Trochanteric Femoral Nail Advanced (TFNA) perforated spiral blade (DePuy Synthes, Paoli, PA) following the manufacturer’s recommendations. The indications for CA are surgeon-dependent. </div><div class = "text-block">Main exposure</div><div class = "text-block">In patients undergoing CA, Traumacem (DePuy Synthes, Paoli, PA), a polymethyl methacrylate (PMMA) cement, will be injected into the blade (3-6mL) under fluoroscopic control. </div><div class = "text-block">Preoperative variables</div><div class = "text-block">The preoperative variables will be compared between the CMN plus CA and CMN only groups: patient demographics (age, sex, height, weight and body mass index [BMI]), Charlson comorbidity index (CCI) [15] (including congestive heart failure, dementia, chronic lung disease, rheumatism, mild liver damage, diabetes with chronic complications, hemiplegia or paraplegia, renal disease, malignancy including leukemia and lymphoma, moderate to severe liver disease, metastatic solid tumors, and HIV/AIDS, American Society of Anaesthesiologists classification, preoperative blood samples results including hemoglobin (Hb) and albumin (Alb), pre-injury residence (single, co-residence, institutional, hospital), osteoporosis, bone mineral density measured at the total hip and forearm using dual-energy x-ray absorptiometry, fracture characteristics based on AO/OTA classification [13], and preoperative waiting period (day of  hospital admission until day of surgery).</div><div class = "text-block">Postoperative variables</div><div class = "text-block">The postoperative variables include physical therapy intervention on postoperative day 1, reduction quality of fracture site, fixation quality, blade position, surgical time (min), and intraoperative blood loss (cc).</div><div class = "text-block">On the postoperative radiograph, the quality of reduction will be rated “good” (normal or slight valgus alignment on the anteroposterior radiograph, <20 degrees of angulation on the lateral radiograph, and maximum 4 mm of displacement of any fragment), “acceptable” (the reduction met the criterion for a “good” reduction with respect to either alignment or displacement but not both) or “poor” (the reduction met neither criteria) according to Baumgaertner (1995) [16]. On postoperative anteroposterior and lateral radiographs, we will assess quality of device placement with the tip–apex distance (TAD) [16], and  the blade tip position by dividing the femoral head into nine zones according to Cleveland et al.(1959) [17].</div><div class = "text-block">Outcomes</div><div class = "text-block">The primary outcome of interest is the total CAS score on postoperative days 1, 2, and 3. The CAS is a valid and reliable assessment tool for evaluating a patient’s mobility by observing the following three basic movements [18] : (1) getting in and out of bed, (2) sitting and rising from a chair (with armrests), and (3) indoor walking (with or without a walking aid).</div><div class = "text-block">The secondary outcomes are pain scores measured using the visual analog scale (VAS) at rest and VAS score during movement on postoperative days 1-3, and the Barthel index at 1-week postoperatively, walking ability (wheelchair, parallel bars, walker, cane or walking alone) and other complications within 1-week postoperatively (coronary artery disease, gastrointestinal bleeding, acute renal failure, delirium [diagnosed based on the confusion assessment method] [19], stroke, venous thrombosis, pneumonia, urinary tract infection, wound infection, pressure ulcer, death, or perioperative blood transfusion) [20]. Intraoperative adverse events related to the CA, such as cement allergy and cement leakage, are also included.</div><div class = "text-block">Sample size calculation</div><div class = "text-block">Based on previous studies using CAS as an outcome variable in acute hip fractures [21], a sample size of 42 patients (21 patients per treatment group) is needed for this study to have 80% power to detect a 2-point mean difference in CAS scores with a type I error of 5%. Therefore, we set  a sample size of 50 patients (25 patients per treatment group) to accommodate for patient dropouts.</div><div class = "text-block">Statistical analyses</div><div class = "text-block">Continuous data with normal distribution will be presented as means ± standard deviations, and compared using t-test. Variables with non-normal distribution will be presented as medians and interquartile ranges and compared using the Mann–Whitney U test. Categorical data will be presented as a proportion of cases and compared using Fisher’s exact test or χ2 test, as appropriate. Univariate and multivariate logistic regression analyses will be performed to clarify the effect of the CA. Significance will be defined as P < .05. All statistical analyses will be performed using EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan).</div><div class = "text-block"><span style = "font-weight:bold;">References</span></div><div class = "text-block">1. Chen IJ, Chiang CY, et al. Nationwide cohort study of hip fractures: time trends in the incidence rates and projections up to 2035. Osteoporos Int 26: 681-688 2015</div><div class = "text-block">2. Dhanwal DK, Dennison EM, et al. Epidemiology of hip fracture: worldwide geographic variation. Indian J Orthop 45: 15-22 2011</div><div class = "text-block">3. Turgut A, Kalenderer Ö, et al. Which factor is most important for occurrence of cutout complications in patients treated with proximal femoral nail antirotation? Retrospective analysis of 298 patients. Arch Orthop Trauma Surg 136: 623-630 2016</div><div class = "text-block">4. Pascarella R, Fantasia R, et al. How evolution of the nailing system improves results and reduces orthopedic complications: more than 2000 cases of trochanteric fractures treated with the Gamma Nail System. Musculoskelet Surg 100: 1-8 2016</div><div class = "text-block">5. Heini PF, Franz T, et al. Femoroplasty-augmentation of mechanical properties in the osteoporotic proximal femur: a biomechanical investigation of PMMA reinforcement in cadaver bones. Clin Biomech (Bristol, Avon) 19: 506-512 2004</div><div class = "text-block">6. Stoffel KK, Leys T, et al. A new technique for cement augmentation of the sliding hip screw in proximal femur fractures. Clin Biomech (Bristol, Avon) 23: 45-51 2008</div><div class = "text-block">7. Yee DKH, Lau W, et al. Cementation: for better or worse?  interim results of a multi-centre cohort study using a fenestrated spiral blade cephalomedullary device for pertrochanteric fractures in the elderly. Arch Orthop Trauma Surg 140: 1957-1964 2020 </div><div class = "text-block">8. Goodnough LH,  Wadhwa H, et al. Trochanteric fixation nail advanced with helical blade and cement augmentation: early experience with a retrospective cohort. Eur J Orthop Surg Traumatol 31: 259-264 2021</div><div class = "text-block">9. Kammerlander C, Hem ES, et al. Cement augmentation of the Proximal Femoral Nail Antirotation (PFNA) - a multicentre randomized controlled trial. Injury 49: 1436-1444 2018</div><div class = "text-block">10. Mattsson P, Alberts A, et al. Resorbable cement for the augmentation of internally-fixed unstable trochanteric fractures. A prospective, randomised, multicentre study. J Bone Joint Surg Br 87: 1203-1209 2005</div><div class = "text-block">11. Kristensen MT, Öztürk B, et al. Regaining pre-fracture basic mobility status after hip fracture and association with post-discharge mortality and readmission-a nationwide register study in Denmark. Age Ageing 48: 278-284 2019</div><div class = "text-block">12. Von Elm E, Altman DG, Egger M, Pocock SJ, Gøtzsche PC, Vandenbroucke JP  et al.  “The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies.” Int J Surg 12: 1495-1499 2014</div><div class = "text-block">13. Meinberg EG, Agel J, et al. Fracture and dislocation classification Compendium-2018. J Orthop Trauma 32 Supplement 1: S1-S170 2018</div><div class = "text-block">14. Chang SM, Zhang YQ, et al. Fracture reduction with positive medial cortical support: a key element in stability reconstruction for the unstable pertrochanteric hip fractures. Arch Orthop Trauma Surg 135: 811-8182015</div><div class = "text-block">15. Quan H, Li B, et al. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 173: 676-682 2011</div><div class = "text-block">16. Baumgaertner MR, Curtin SL, et al. The value of the tip-apex distance in predicting failure of fixation of peritrochanteric fractures of the hip. J Bone joint Surg Annu 1995</div><div class = "text-block">17. Cleveland M, Bosworth DM, et al. A ten-year analysis of intertrochanteric fractures of the femur.J Bone Joint Surg Am 41-A: 1399-1408 1959</div><div class = "text-block">18. Foss NB, Kristensen MT, et al. Prediction of postoperative morbidity, mortality and rehabilitation in hip fracture patients: the cumulated ambulation score. Clin Rehabil 20: 701-708 2006</div><div class = "text-block">19. Inouye SK, van Dyck CH, et al. Clarifying confusion: the confusion assessment method: A new method for detection of delirium. Ann Intern Med 113 1990</div><div class = "text-block">20. Sink EL, Leunig M, et al. Reliability of a complication classification system for orthopaedic surgery. Clin Orthop Relat Res 470: 2220-2226 2012</div><div class = "text-block">21. Hulsbæk S, Larsen RF, et al. The Barthel Index and the Cumulated Ambulation Score are superior to the de Morton Mobility Index for the early assessment of outcome in patients with a hip fracture admitted to an acute geriatric ward. Disabil Rehabil 41: 1351-1359 2019</div></div>

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