Atypical periprosthetic femoral fractures after arthroplasty for fracture are at high risk of complications.

It is difficult to investigate clinical features in a single-center study because atypical periprosthetic femoral fracture (APFF) is rare. This study aims to perform a nationwide survey of APFF to investigate the characteristics of this fracture and compare the clinical outcome with that of typical periprosthetic femoral fracture (typical PFF). A nationwide survey was performed asking for cooperation from 183 councilors of the Japanese Society for Fracture Repair. The subjects were patients with APFF injured between 2008 and 2017. The control group was comprised of patients with typical PFF of our facility injured in the same period. A total of 43 patients met the APFF definition. The control group was comprised of 75 patients with typical PFF. The rate of bisphosphonate use was significantly higher in the APFFs group than in the typical PFF group (62.8% and 32%, p < 0.02). The rate of cemented stem was significantly higher in the APFFs group than in the typical PFF group (30.2% and 6.7%, p < 0.001). In the patients with arthroplasty for hip fracture, multivariable logistic regression analyses showed that APFF was an independent risk factor of complications following the initial management (Odds ratio 11.1, 95% confidence interval 1.05-117.2, p = 0.045). However, no significant association between PFF and APFF was observed in the patients with arthroplasty for other hip diseases. The risk of complications was higher in the APFF group than in the typical PFF group in the patients with arthroplasty for fracture. When AFPP after arthroplasty for the fracture is suspected, it may be necessary to add not only internal fixation with a normal plate but also some additional treatment.

Undisplaced femoral neck fractures need a closed reduction before internal fixation.

INTRODUCTION: Undisplaced femoral neck fractures (UFNF) are generally treated with in situ internal fixation, and few studies have addressed the impact of closed reduction. The aim of this study was to investigate the clinical outcome of UFNF treated with internal fixation using the Hansson pinloc system after closed reduction. PATIENTS AND METHODS: This was a retrospective study of 40 patients who underwent internal fixation using the Hansson pinloc system after closed reduction between September 2014 and May 2016. In the present study, posterior tilt, presence of complete fracture, interval from injury to surgery, and changes in activities of daily living were statistically analyzed to investigate the association between nonunion and late segmental collapse (LSC). RESULTS: Five cases each of nonunion and LSC were identified. The frequency of LSC was significantly higher in patients with preoperative posterior tilt ≥ 20° (p < 0.05). The risks of nonunion and LSC were lower in patients with incomplete fracture (p < 0.05) and fixation within 48 h (p < 0.05). Of the 40 patients, 34 were categorized in the sufficient reduction group fixed with posterior tilt ≤ 5°. Secondary operation rate was lower in the sufficient reduction group (5/34 cases) than in the insufficient reduction group (3/6 cases). DISCUSSION: The fixation timing < 48 h decrease the risk of fracture healing complications and sufficient reduction may reduce the risk of secondary operation. Preoperative posterior tilt ≥ 20° and complete fractures on CT scans were related to poor prognosis.