FEMORAL NECK FRACTURES GARDEN I AND II: EVALUATION OF THE DEVIATION IN LATERAL VIEW

Sagittal deformity of Garden type I and II geriatric femoral neck fractures is frequently misclassified by lateral radiographs

The objective of this study was to determine the validity and inter-rater reliability of radiographic assessment of sagittal deformity of femoral neck fractures.

Design

This is a retrospective cohort study.

Setting

Level 1 trauma center.

Patients/Participants

Thirty-one patients 65 years or older who sustained low-energy, Garden type I/II femoral neck fractures imaged with biplanar radiographs and either computed tomography or magnetic resonance imaging were included.

Main Outcome Measurements

Preoperative sagittal tilt was measured on lateral radiographs and compared with the tilt identified on advanced imaging. Fractures were defined as "high-risk" if posterior tilt was ≥20 degrees or anterior tilt was >10 degrees.

Results

Of 31 Garden type I/II femoral neck fractures, advanced imaging identified 10 high-risk fractures including 8 (25.8%) with posterior tilt ≥20 degrees and 2 (6.5%) with anterior tilt >10 degrees. Overall, there was no significant difference between sagittal tilt measured using lateral radiographs and advanced imaging (P = 0.84), and the 3 raters had good agreement between their measurements of sagittal tilt on lateral radiographs (interclass correlation coefficient 0.79, 95% confidence interval [0.65, 0.88], P < 0.01). However, for high-risk fractures, radiographic measurements from lateral radiographs alone resulted in greater variability and underestimation of tilt by 5.2 degrees (95% confidence interval [-18.68, 8.28]) when compared with computed tomography/magnetic resonance imaging. Owing to this underestimation of sagittal tilt, the raters misclassified high-risk fractures as "low-risk" in most cases (averaging 6.3 of 10, 63%, range 6 - 7) when using lateral radiographs while low-risk fractures were rarely misclassified as high-risk (averaging 1.7 of 21, 7.9%, range 1 - 3, P = 0.01).

Conclusions

Lateral radiographs frequently lead surgeons to misclassify high-risk sagittal tilt of low-energy femoral neck fractures as low-risk. Further research is necessary to improve the assessment of sagittal plane deformity for these injuries.

Level of Evidence

Level IV diagnostic study.

Finite element analysis of necessity of reduction and selection of internal fixation for valgus-impacted femoral neck fracture

This study compared the biomechanical characteristics of different treatment strategies based on finite element analysis. Posterior tilt and valgus angle were measured on X-ray from ten valgus-impacted femoral neck fractures, and 7 finite element models that were generated to compare the stress and displacement. The results showed that in the intact femur, von Mises stress was concentrated at the medial and inferior sides of the femoral neck. In valgus-impacted femoral neck fractures, von Mises stress was at the same locations but was 5.66 times higher than that in the intact femur. When 3 cannulated screws were used for internal fixation, anatomic reduction diminished the stress at the fracture end from 140.6 to 59.14 MPa, although displacement increased from 0.228 to 0.450 mm. When the fracture was fixed with a sliding hip screw (SHS) + cannulated screw, there was less stress at the fracture end and greater displacement with anatomic reduction than that without reduction (stress: 15.9 vs 37.9 MPa; displacement: 0.329 vs 0.168 mm). Therefore, the SHS + cannulated screw has superior biomechanical stability than 3 cannulated screws, and is recommended following anatomic reduction to treat valgus-compacted femoral neck fractures.

Poor results of functional treatment of Garden-1 femoral neck fracture in dependent patients

INTRODUCTION

Variable results are reported after functional treatment for Garden-1 femoral neck fracture, with no definite factors for failure, particularly in the absence of selection for risk. It seems well indicated in frail and/or dependent patients with comorbidities, but this has not been specifically assessed, and failure is frequent in this target population. We therefore performed a retrospective study to: (1) assess results of functional treatment for Garden-1 impacted femoral neck fracture in dependent patients, and (2) analyze survival in terms of complications and death, and related factors.

HYPOTHESIS

Functional treatment for Garden-1 fracture in dependent patients gives poor results, with a high rate of surgical revision.

MATERIAL AND METHODS

A retrospective analysis was made of Garden-1 femoral neck fracture in dependent patients (Parker score≤5), with a minimum 2 years' follow-up. One hundred and forty-six patients were included: mean age, 81.3±8.7 years (range, 55.7-99.6 years). The endpoint was survival in terms of complications requiring surgery, secondary displacement requiring surgery, excessive pain requiring surgery, non-union or femoral head osteonecrosis. Secondary endpoints were overall mortality and mortality related to complications.

RESULTS

Mean follow-up was 4.2±2.6 years (range, 2.0-10.3 years). Ninety-one of the 146 patients (62.3%) required secondary surgery: 79 (54.1%) early (<3 months post-fracture), with 77 (52.7%) secondary displacements and 2 cases (1.4%) of excessive pain; and 12 (8.2%) late (162.2±132.3 days; range, 90-454 days), with 8 (5.4%) non-unions and 4 (2.7%) osteonecroses. Mean time to onset of secondary displacement was 13.6±11.8 days (range, 0-67.0 days). Two-year survival in terms of revision surgery was 34.1% [95% CI: 26.0-42.4]. At last follow-up, 91 patients (62.3%) had died; 2-year survival in terms of death was 69.9% [95% CI: 62.4-77.3]. Survival analysis in terms of complications revealed greater mortality in absence of complications: 42 of the 55 patients (76.3%) without complications requiring surgery died, versus 49 of the 91 (53.8%) with complications requiring surgery (p=0.012); relative risk of death in absence of complications requiring surgery was 1.42 [95% CI: 1.33-5.77].

DISCUSSION

Functional treatment for Garden-1 fracture in dependent patients gave poor short- and medium-term results. Surgery is therefore recommended in this specific population; the present findings should improve survival.

LEVEL OF EVIDENCE

IV, retrospective study.