gms | German Medical Science

Objectives: Low-impact and, at times, atraumatic FFP are an ever more common challenge for orthopaedic surgeons. These osteoporotic fractures differ significantly from high-impact fractures and require particular vigilance for diagnosis. Due to the complex biomechanics of the pelvic rim, FFP cause an alteration in the gait and pain during ambulation. The alterations vary between anterior, posterior, unilateral and bilateral involvements. The most widely used FFP classification by Rommens and the recently established OF classification by the German Society for Orthopaedics and Trauma (DGOU) attempt to represent the pelvic stability. Both classifications are based on similar criteria (unilateral, bilateral, anterior and posterior involvement); thus, significant gait differences between them are unlikely. Here we aim to evaluate how these classifications depict gate alterations using quantitative gait analysis.

Methods: From June 2020 until December 2022, we included 54 patients (Age: 84.2 ± 6.79 (Mean ± SD); 90.7% female) with FFP diagnosed by conventional computer tomography (CT). They were retrospectively incorporated and classified according to the classifications mentioned above. We performed quantitative gait analysis using in-sole sensors (Loadsol®; Novel, Munich, Germany). Average and maximum peak force in relation to body weight (avgPF% and maxPF%)and the force-time integral ratio (FTI ratio), a measure of gait imbalance, were assessed during ambulation. Pairwise comparison according to the FFP and OF classification was performed.

Results and conclusion: Regardless of fracture type and classification, FFP resulted in a significant reduction in mobility. Isolated anterior pelvis fractures (FFP1 and OF2) showed a reduction in the avgPF% between the fractured and healthy side. Similar results were observed for bilateral posterior fractures (FFP4 and OF4). FFP2 and 3 fractures are represented in OF3 fractures, representing unilateral posterior pelvic fractures. This group made up the majority of cases and showed a significant reduction in the avgPF% placed on the injured side (FFP2: 70.70 ± 15.29 % vs. 60.71 ± 16.24%; OF3: 69.98 ± 16.71% vs. 58.01 ± 16.70% (mean ± SD)), likely due to the rotational and transmission pelvis force causing pain-elicited protection of the injured side in 92% of cases. Both classifications captured this equally well. Due to the limited number of patients subgroup analysis could not be performed (FFP2 vs. 3). Additionally, all our patients were diagnosed through CT; thus, radiologically occult OF1 fractures are not depicted.

Gait analysis using in-sole sensors offers a unique insight into the gait changes and reduction of the tolerated weight. The currently established FFP classification and the new OF classification both represent this to the same degree, with no superiority between them. Further, research should focus on the often undiagnosed radiologically occult fractures and how these provoke gait alterations.