Importance of sliding screw position in trochanteric fracture. 4 cases of secondary cervical fracture

Femoral neck fractures after internal fixation of trochanteric fractures with implants in situ in adults: A systematic review

INTRODUCTION

Femoral neck fractures (FNF) after internal fixation of trochanteric fractures (AIFTF) with the implant in situ (WIIS) are uncommon. Publications of FNFAIFTFWIIS are rare. The purpose of this systematic review of the literature is to report on the frequency, risk factors, mechanisms, clinical presentation, diagnostic and therapeutic modalities, outcomes and the eventual prevention of this complication.

MATERIALS AND METHODS

A comprehensive review of the literature was undertaken using the PRISMA guidelines with no language restriction. Case reports of FNFAIFTFWIIS and series of trochanteric fractures (TF) with this complication in adults published between inception of journals to May 2018 were eligible for inclusion. Cases with fractures in pathological bone, undergoing treatment with hip replacement, or after partial or total implant removal were excluded. Relevant information was divided in two parts. Part I included the analysis of cases of FNFAIFTFWIIS, with the objective of establishing the eventual risk factors, mechanisms, diagnostic, treatment modalities, and outcomes. Part II analyzed series of TFs with implants in situ which included cases of FNFs for assessing the incidence of FNFs in this condition.

RESULTS

Overall 77 publications with 104 cases of FNFAIFTFWIIS met the inclusion criteria. The median incidence of this complication was 0,43%. The mean age was 80 years (range, 42-96).The prevalent factors for FNFAIFTFWIIS were osteoporosis, and the presence of the implant in the femoral neck and head. A short nail or screw with the tip far from the subchondral bone was of influence as a stress riser factor, but not prevalent because in two thirds of the cases the FNF occurred when the implant was introduced up to the subchondral bone. Other risk factors analysed included varus reduction or nonunion of the TF, and the breakage of the hip screw, which modify the forces exerted over the femoral neck, and may contribute to the FNF. The FNFs were spontaneous, i.e. not related to trauma or fall, in more than two thirds of the cases.

CONCLUSION

The etiology of FNFAIFTFWII should be considered multifactorial. The frequency seems low. Although a subchondral positioning of the hip screw might diminish the incidence of FNFS, a correct surgical technique does not preclude a FNFAIFTFWIIS, and in fact the incidence of this complication was higher in these correctly treated patients. FNFAIFTFWIIS is a fragility fracture and adequate management of systemic osteoporosis should be targeted as a main factor of prevention.

Ipsilateral Intracapsular Hip Fracture 2 Years after Fixation of Extracapsular Fracture by Dynamic Hip Screw

INTRODUCTION

Sustaining an intracapsular fracture in a hip which was previously fixed with dynamic hip screw for extracapsular fracture, is a very rarely reported occurrence. We present one such case in order to discuss the presentation and management of this fracture. We have also reviewed the literature and pooled the previously reported cases to look at potential cause & risk factors.

CASE REPORT

A 92 year old female, presented with new onset hip pain following a trivial injury. Couple of years back, she had sustained an extracapsular fracture on same side which was treated by DHS fixation. Further investigations confirmed a de-novo fracture which was treated by removal of DHS and cemented bipolar hemiarthroplasty.

CONCLUSION

This complication might not be as rare as earlier thought to be. All patients, especially elderly females who present with new onset hip pain following DHS fixation of their hip fracture previously must be evaluated for a de-novo intracapsular fracture. On confirmation of diagnosis, they can be treated by removal of dynamic hip screw and hemiarthroplasty as most of these are low demand elderly patients.

Femoral neck fracture after removal of the compression hip screw from healed intertrochanteric fractures

OBJECTIVES

To evaluate the incidence of femoral neck fracture (FNF) after removal of a compression hip screw (CHS) without trauma and to determine the risk factors for this type of fracture.

DESIGN

Retrospective study of consecutive patient series.

SETTING

University teaching hospital.

PATIENTS

Sixty-seven patients with a mean age of 65.3 years (45 women and 22 men).

INTERVENTION

A total of 67 implants were removed in the presence of bony consolidation of the fracture site; most of them were due to hardware pain.

MAIN OUTCOME MEASURES

The incidence of FNF after a CHS removal, clinical parameters (age, gender, bone mineral density, body mass index, and fracture stability), and radiologic parameters (the femoral neck-shaft angle, femoral neck width, distance between thread of lag screw, and neck cortex). Univariate analysis was performed for those parameters of the fracture group and the nonfracture group. To assess which variables were associated with FNF, a multiple logistic regression was used.

RESULTS

Six (9.0%) FNFs occurred within 1 month after a CHS removal. The mean anterior and lateral neck widths were significantly smaller, and the mean anterior and inferior thread-to-cortex distances were significantly shorter in the fracture group compared with the nonfracture group. The risk factor significantly associated with FNF was the inferior thread-to-cortex distance (odds ratio, 0.462; 95% confidence interval, 0.217-0.988).

CONCLUSIONS

CHS should not be removed routinely due to the risk of FNF. Furthermore, attention should be paid to at-risk patients with a hip screw positioned close to the inferior femoral neck cortex.

LEVEL OF EVIDENCE

Prognostic level II.

Biopolymer augmentation of the lag screw in the treatment of femoral neck fractures--a biomechanical in-vitro study

The cut-out of the sliding screw is one of the most common complications in the treatment of intertrochanteric fractures. The reasons for the cut-out are: a suboptimal position of the hip-screw in the femoral head, the type of fracture and poor bone quality. The aim of this study was to reproduce the cut-out event biomechanically and to evaluate the possible prevention of this event by the use of a biopolymer augmentation of the hip screw. Concerning the density and compression force of osteoporotic femoral bone polyurethane foam according to the terms of the Association for Standard Testing Material (ASTMF 1839-97) was used as test material. The polyurethane foam Lumoltan 200 with a compression force of 3.3 Mpa and a density of 0.192 g/cm(3) was used to reproduce the osteoporotic bone of the femoral fragment (density 12 lbm/ft(3)). A cylinder of 50 mm of length and 50 mm of width was produced by a rotary splint raising procedure with planar contact. The axial load of the system was performed by a hydraulic force cylinder of a universal test machine type Zwick 1455, Ulm, Germany. The CCD-angle of the used TGN-System was preset at 130 degrees. The migration pattern of the hip screw in the polyurethane foam was measured and expressed as a curve of the distance in millimeter (mm) against the applied load in Newton (N) up to the cut-out point. During the tests the implants reached a critical changing point from stable to unstable with an increased load progression of steps of 50 Newton. This unstable point was characterized by an increased migration speed in millimeters and higher descending gradient in the migration curve. This peak of the migration curve served as an indicator for the change of the hip screw position in the simulated bone material. The applied load in the non-augmented implant showed that in this group for a density degree of 12 (0,192 g/cm(3)) the mean force at the failure point was 1431 Newton (+/- 52 Newton). In the augmented implant we found that the mean force at the failure point was 1987 Newton (+/- 84 Newton). This difference was statistically significant. In conclusion, the bone density is a significant factor for the stability of the hip screw implant. The osteosynthesis with screws in material with low density increases the chance for cut-out. A biopolymer augmented hip screw could significantly improve the stability of the fixation. The use of augmentation with a fast hardening bone replacement material containing polymer-ceramic changes the point of failure under axial load in the osteoporotic bone model and could significantly improve the failure point. Our study results indicate, that a decrease of failure in terms of cut-out can be achieved with polymer augmentation of hip screws in osteoporotic bones.

Subcapital femoral neck fracture following successful trochanteric fracture treatment with a dynamic hip screw: a report of five cases

A subcapital femoral neck fracture complicating a healed trochanteric fracture is rare. Such cases are managed in a rather heterogeneous manner, i.e. there exists a mixture of cases treated by either fixed angle devices or dynamic compression screws. We describe 5 patients who developed subcapital femoral neck fractures after healed trochanteric fractures treated with dynamic compression screws. The subjects' clinical data, operative records, and radiographs have been studied retrospectively and the literature reviewed. The risk factors for such a complication include being of advanced age, female, osteoporotic, and having a small femoral head and neck, and a basicervical type of fracture.