Hip osteoarthritis as a predictor of the fracture pattern in proximal femur fractures.

Introduction: Several authors have suggested a correlation between the fracture patterns of proximal femur fractures and the degree of hip osteoarthritis (HOA), but the current evidence to support this are insufficient. The aim of our study was to demonstrate whether there is an association between the grade of HOA and fracture pattern observed, in patients presenting with a fragility fracture of the proximal femur.
Materials and Methods: We contacted a retrospective review of all patients presenting to our institution with fragility fractures involving the proximal femur, between March 2012 and October 2013. Pathological fractures, high-energy injuries and patients with less than one year of follow-up were excluded from further analysis. Admission radiographs and severity of HOA were assessed according to Kellgren and Lawrence scale (minimal: Grades 1-2; severe: Grades 3-4). Fractures were classified according to AO/OTA classification.
Results: A total of 1003 patients (725 females; 1003 fractures) met the inclusion criteria, having a mean age of 81.5 (46-106 years). With regards to fracture classification, 417 (41.6%) fractures were classified as extracapsular and 586 (58.4%) as intracapsular. A total of 939 (93.9%) patients presented with minimal HOA, whilst 61 (6.1%) of the patients presented with severe HOA. Of the 61 patients presenting with severe HOA, 42 patients (68.9%) sustained a 31A-interthrocanteric fracture and 19 patients (31.1%) sustained a 31B-intracapsular fracture. Regarding the patients presenting with minimal HOA (832 patients in total), 323 patients (38.8%) sustained 31A-intertrochanteric fracture and 509 patients (61.2%) sustained a 31B-intracapsular fracture. Patients presenting with severe HOA were found to have a statistically significant chance to present with an extracapsular fracture (p<0.01).
Conclusions: The degree of HOA is related to the fracture pattern in patients presenting following simple mechanical falls. More specifically, higher grades of HOA are associated with extracapsular fracture patterns, whereas lower grades of HOA are associated with intracapsular fracture patterns.
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