Relative lateral wall thickness is an improved predictor for postoperative lateral wall fracture after trochanteric femoral fracture osteosynthesis

Scientific Reports, vol. 13, pp. 17750

Abstract

Lateral wall thickness is a known predictor for postoperative stability of trochanteric femoral fractures and occurrence of secondary lateral wall fractures. Currently, the AO/OTA classification relies on the absolute lateral wall thickness (aLWT) to distinguish between stable A1.3 and unstable A2.1 fractures that does not take interpersonal patient differences into account. Thus, a more individualized and accurate measure would be favorable. Therefore, we proposed and validated a new patient-specific measure-the relative lateral wall thickness (rLWT)-to consider individualized measures and hypothesized its higher sensitivity and specificity compared with aLWT. First, in 146 pelvic radiographs of patients without a trochanteric femoral fracture, the symmetry of both caput-collum-diaphyseal angle (CCD) and total trochanteric thickness (TTT) was assessed to determine whether the contralateral side can be used for rLWT determination. Then, data of 202 patients were re-evaluated to compare rLWT versus previously published aLWT. Bilateral symmetry was found for both CCD and TTT (p ≥ 0.827), implying that bone morphology and geometry of the contralateral intact side could be used to calculate rLWT. Validation revealed increased accuracy of the rLWT compared with the gold standard aLWT, with increased specificity by 3.5% (Number Needed to Treat = 64 patients) and sensitivity by 1% (Number Needed to Treat = 75 patients). The novel rLWT is a more accurate and individualized predictor of secondary lateral wall fractures compared with the standard aLWT. This study established the threshold of 50.5% rLWT as a reference value for predicting fracture stability in trochanteric femoral fractures.

Authors 9

1. Kenneth P. van Knegsel corresponding

   University of Zurich · Luzerner Kantonsspital

   Affiliation as printed

   AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland. Kennethpetrus.vanknegsel@uzh.ch

   Department of Orthopedics and Trauma Surgery, Lucerne Cantonal Hospital, Spitalstraβe 16, 6000, Lucerne, Switzerland. Kennethpetrus.vanknegsel@uzh.ch

   Medical Faculty, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland. Kennethpetrus.vanknegsel@uzh.ch

   Department of Orthopedics and Trauma Surgery, Lucerne Cantonal Hospital, Spitalstraβe 16, 6000, Lucerne, Switzerland

2. Cheng-En Hsu

   Tunghai University · Taichung Veterans General Hospital

   Affiliation as printed

   Department of Orthopedics, Taichung Veterans General Hospital, Taichung, Taiwan

   Sports Recreation and Health Management Continuing Studies-Bachelor's Degree Completion Program, Tunghai University, Taichung, 407, Taiwan

3. Kui Huang

   Asia University · Asia University Hospital

   Affiliation as printed

   Department of Occupational Therapy, Asia University, Taichung, Taiwan

   Department of Orthopedics, Asia University Hospital, Taichung, Taiwan

4. Emir Benca

   AO Foundation · Medical University of Vienna

   Affiliation as printed

   AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland

   Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria

5. Torsten Pastor

   AO Foundation · Luzerner Kantonsspital

   Affiliation as printed

   AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland

   Department of Orthopedics and Trauma Surgery, Lucerne Cantonal Hospital, Spitalstraβe 16, 6000, Lucerne, Switzerland

6. Bergita Ganse

   Universitätsklinikum des Saarlandes · Saarland University

   Affiliation as printed

   Department of Trauma, Hand and Reconstructive Surgery, Saarland University Hospital, 66421, Homburg, Germany

   Werner Siemens Foundation Endowed Chair for Innovative Implant Development, Clinics and Institutes of Surgery, Saarland University, 66421, Homburg, Germany

7. Peter Varga

   AO Foundation

   Affiliation as printed

   AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland

8. Boyko Guergov Gueorguiev

   AO Foundation

   Affiliation as printed

   AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos, Switzerland

9. Matthias Knobe Aachen Medical Faculty

   University of Zurich · Universitätsklinikum Aachen · RWTH Aachen University

   Affiliation as printed

   Department of Orthopaedic Trauma, Westmuensterland Hospital, Wuellener Strasse 101, 48683, Ahaus, Germany

   Medical Faculty, RWTH Aachen University Hospital, Pauwelsstrasse 30, 52074, Aachen, Germany

   Medical Faculty, University of Zurich, Raemistrasse 100, 8091, Zurich, Switzerland