Background Neck of femur (NOF) fractures, including intertrochanteric fractures, are common fragility fractures seen in the elderly population and are often amenable to fixation with a proximal femoral nail (PFN). However, there is conflicting evidence regarding the incidence of peri-prosthetic fractures with each device. Several studies from the 1990s and a recent meta-analysis have shown a higher incidence of peri-prosthetic fractures in the short PFN cohort. Other studies have shown a lower reoperation rate with short PFNs, and no statistically significant differences have been quoted in the rates of peri-prosthetic fractures in systematic reviews. Aim The purpose of this retrospective study, therefore, was to assess the peri-prosthetic fracture rate and failure rates of elderly neck of femur (NOF) fractures implanted with either a short or long proximal femoral nail (PFN). Materials and methods A retrospective study was conducted in a single orthopaedic department (University Hospital Dorset, Poole, GBR) using collected data on all extracapsular neck of femur fracture patients from the national hip fracture database (NHFD) from January 1, 2011, to December 23, 2021. The data collected included patient age, sex, the American Society of Anesthesiologists (ASA) type of neck of femur fracture, type of surgery performed, any further peri-prosthetic fractures, and time to re-operation in that subset of the group. The implants used were the Stryker Gamma 3 Nail and the Smith Nephew (Trigen and Intertan). All patients were allowed to fully weight bear as tolerated and received both orthopaedic and elderly medical care. Failure was defined as a cut-out or implant fracture. Results From January 1, 2011, to December 23, 2021, there were 1010 extracapsular neck of femur fractures recorded on the National Hip Fracture Database (NHFD) treated with a PFN from the study centre. Of those patients, 11 had pathological fractures and were excluded. 649 patients had long PFNs, and 350 had short PFNs. Of the total of 999 patients, 254 (25%) were male and 745 (75%) were female. More than 80% of the patients in the sample were over the age of 75. The majority of patients in both groups had A1/A2 fractures (short 84.3%, long 49.1%). The rate of periprosthetic fractures in the short PFNs was 1.71%, and the failure rate was 0.57%. The rate of periprosthetic fractures in the long PFNs was 0.62%, with a failure rate of 0.92%. The multi-nominal logistic regression model did not show statistically significant odds ratios (OR) for the following variables: long/short nails, male/female gender, age, ASA, or type of fracture. The female gender was associated with a higher risk of both periprosthetic fractures and failures (OR of 2.232 and 2.95), but this was not found to be statistically significant. Similarly, unstable A3 fractures had a much higher risk of failure (OR of 2.691) compared to periprosthetic fractures (OR of 0.985). However, this was not statistically significant. Conclusion Overall, this study has identified that in a patient population that is predominantly female and over the age of 75, the risk of periprosthetic fracture rate and the failure rate is similar in both the use of a short or a long PFN for intertrochanteric fractures.
Keywords: elderly population; femur intertrochanteric fracture; fragility fracture; neck of femur fracture (nof); neck of femur fractures; nof; orthopaedics surgery; periprosthetic fracture; proximal femoral nail.
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