A three-dimensional comparison of intramedullary nail constructs for osteopenic supracondylar femur fractures

Fractures of the distal femur in elderly patients: retrospective analysis of a case series treated with single or double plate

Introduction

We evaluated the radiologic and clinical outcomes of a lateral incision single plate with and a single-incision double plating in elderly patients with osteoporotic distal femoral fractures.

Materials and methods

We performed a retrospective study of 82 cases of distal femoral fractures from May 2004 to June 2018. Group A consisted of 42 patients who underwent single-plate fixation. Group B consisted of 40 patients who underwent double-plate fixation. The mean patient age was 77 years (67–87 years) and 76 years (64–86 years) in groups A and B, respectively. All patients were evaluated for procedure duration, time to union, range of knee motion, Lysholm knee score, and presence of complications.

Results

The average procedure time was 81 min (66–92 min) and 110 min (95–120 min) in groups A and B, respectively (p = 0.33). One case in group B required bone grafting after 5 months. The average time to union was 14 weeks (9–19 weeks) and 12.2 weeks (8–19 weeks) (p = 0.63), and the mean range of knee motion was 105° (90–125°) and 110.7° (90°–130°) (p = 0.37) in groups A and B, respectively. There was no significant statistical difference between the two groups in the Lysholm knee score (p = 0.44) and knee society score (p = 0.53).

Conclusion

The clinical and radiological outcomes were similar in the 2 groups. In elderly patients, double plate fixation for distal femoral fractures is an useful method for several advantages such as adequate exposure, easy manipulation, anatomical reduction and stable fixation.

Comparative analysis of the biomechanical behavior of anterograde/retrograde nailing in supracondylar femoral fractures

Supracondylar femoral fractures account for a noticeable percentage of the femoral shaft fractures, affecting two etiological groups: high energy trauma in young men, with good bone quality, and older women with osteoporotic femur. Surgical treatment of those kind of fractures remains controversial, with different surgical options such as plate and sliding barrel locking condylar plate, less invasive stabilization system (LISS) or intramedullary nailing, which has emerged as a new fixation choice in the treatment of that type of fractures. The present work performs a comparative study about the biomechanical behavior of anterograde and retrograde nailing in supracondylar femoral fractures type A, in order to determine the best choice of nailing and locking configuration. A three-dimensional finite element model of the femur was developed, modeling femoral supracondylar fracture and different nailing configurations, both for anterograde and retrograde nails. The study was focused on the immediately post-operative stage, verifying the appropriate stability of the osteosynthesis. The obtained results show a better biomechanical behavior for anterograde nails, providing a better stability from the point of view of global movements, lower stresses in screws, and less stress concentration in cortical bone. So, for the analyzed fractures and osteosyntheses types, anterograde nailing has demonstrated to be a better surgical option, being an excellent indication in supracondylar fractures of femur, with clear benefits compared to retrograde nailing, providing a better stabilization which enables for a more satisfactory fracture healing.

Osteoporotic distal femur fractures in the elderly: peculiarities and treatment strategies

Distal femur fractures account for 4-6% of osteoporosis related fractures of the femur in the elderly population. They represent a relevant cause of morbidity and mortality in the geriatric population with a reported 1-year mortality reaching 30%. Non-displaced fractures or even displaced fractures in patients with high operative risk can be treated conservatively. However, operative treatment is the most widely accepted management option for displaced fractures. The advantage resides in early mobilization and weight-bearing, reducing risks related with a prolonged immobilization when compared with conservative treatment. On the other hand, the intrinsic difficulty of fixing an osteoporotic bone is a major concern. The presence of osteosynthesis devices or prosthetic implants in the femur can make the surgical treatment more challenging, sometimes limiting therapeutic options. Aim of the present paper is to review the most recent literature about osteoporotic distal femur fractures in the elderly, including periprosthetic and other hardware related fractures, to highlight current evidence on management options and related results as a guide for the daily clinical practice.

Comparison of Less Invasive Stabilization System Plate and Retrograde Intramedullary Nail in the Fixation of Femoral Supracondylar Fractures in the Elderly: A Biomechanical Study

Objective

To compare the biomechanical stabilities of less invasive stabilization system (LISS) plate and retrograde intramedullary nail (IMN) for the comminuted femoral supracondylar fracture fractures in the elderly.

Methods

Sixteen pairs of embalmed cadaver femurs were obtained to simulate a comminuted supracondylar femur fracture (AO/OTA33‐A3) gap model. All left‐side specimens were fixed with LISS plate, and retrograde IMN were applied to the right‐side specimens. All specimens were tested in torsional, axial and cyclic load mode on an Instron testing machine.

Results

The mean torsional stiffness for LISS plate group was 34.1% greater than retrograde IMN group (2.90 vs. 1.91 Nm/degree, P = 0.002), but the mean axial stiffness was greater for the retrograde IMN (199.16 vs. 303.93 N/mm, P < 0.001). The total deformation of LISS plate caused by cyclic axial loading was greater than retrograde IMN (4.17 vs. 3.57 mm, P = 0.014). Significantly less mean irreversible deformation was detected in LISS plate than in retrograde IMN (1.64 vs. 1.69 mm, P = 0.699). Failure loads of the constructs were significantly different between the two groups (LISS plate: 2941±128 N; retrograde IMN: 4022±176 N, P < 0.001).

Conclusion

For comminuted femoral supracondylar fractures in the elderly, the tested instruments can both maintain sufficient biomechanical stabilities, but retrograde IMN is superior to LISS plate in deformation of fracture site.

A double-plating approach to distal femur fracture: A clinical study

BACKGROUND

Locked plating is one of the latest innovative options for treating supracondylar femur fractures with relatively low failure rates. Single lateral plating was often found to have a relative higher failure rate. No clinical studies of double-plating distal femur fixation have thus far been reported. The aim of this study is to present our clinical experience with this surgical approach.

PATIENTS AND METHODS

Thirty-two patients (26 females and 6 males, mean age 76 years, range 44-101) were included in the study. Eight of them patients had a periprosthetic stable implant fracture and two patients were treated for a nonunion.

RESULTS

All fractures, excluding one that needed bone grafting and one refracture, healed within 12 weeks. One patient needed bone grafting for delayed union and one patient needed fixation exchange due to femur re-fracture at the site of the most proximal screw. Two patients developed superficial wound infection and one patient required medial plate removal after union due to deep infection.

CONCLUSIONS

Based on these promising results, we propose that the double-plating technique should be considered in the surgeon's armamentarium for the treatment of supracondylar femur fractures, particularly in patients with poor bone quality, comminuted fractures and very low periprosthetic fractures.

Retrograde dynamic locked intramedullary nailing for aseptic supracondylar femoral nonunion after dynamic condylar screw treatment

OBJECTIVE

Supracondylar femoral nonunions after dynamic condylar screw (DCS) treatment are uncommon, and few studies have addressed an optimal treatment technique for this disorder. Re-insertion of a new plate may not be secure because of bony defects in the distal fragment, created by the lag screw of the DCS.

MATERIALS AND METHODS

Forty-two consecutive adult patients with 42 supracondylar femoral nonunions were treated with removal of the DCS, re-alignment of the knee axis, and insertion of a retrograde dynamic traditional femoral locked nail. When necessary, a humeral plate was augmented to reinforce rotational stability.

RESULTS

A final group of 36 patients with 36 nonunions were followed for an average of 2.8 years (range 1.1-6.2 years). All nonunions healed with a union rate of 100 %, and the average time to union was 4.2 months (range 2.5-5.5 months). Complications included two malunions. There were no instances of nonunion or deep infection. Satisfactory knee function among 36 patients improved from 8.2 % preoperatively to 86.1 % at the last follow-up (p < 0.001). All 36 patients could walk without aids.

CONCLUSION

The described technique may be an excellent alternative treatment for an aseptic supracondylar femoral nonunion after DCS treatment. The technique is not difficult, and the union rate and satisfactory rate are high.

Prospective comparative study of two methods for fixation after distal femur corrective osteotomy for valgus deformity; retrograde intramedullary nailing versus less invasive stabilization system plating

INTRODUCTION

The aim of this study was to compare the radiological and functional results of two different methods of fixation for the correction of femoral valgus deformities.

METHODS

Patients who had undergone osteotomy and correction of a valgus deformity from 2007 to 2013 were prospectively followed. Thirty three patients (20 females, 13 males) with 39 lower limbs were included in the study. Seventeen lower limbs were treated with retrograde intramedullary nailing (IMN) and 22 with less invasive stabilization system plating. Standing orthoroentgenograms of the lower limbs were taken pre-operatively and at the final follow-up. mLDFA, aLDFA, mechanical axis deviation (MAD) were measured in this orthoroentgenograms. Knee osteoarthritis outcome score (KOOS) and knee range of motion were used pre-operatively and at the final follow-up as part of the evaluation of the clinical results. All patients duration of surgery, length of hospital stay were assessed. Operations were performed by two orthopedic surgeons. The choice of correction method for each patient was determined by the surgeon. Pre-operative and post-operative values were simultaneously measured by two additional orthopedic surgeons.

RESULTS

The mean age of the patients was 26.2 years (18.0-51.0) in the plating group and 29.3 years (18.0-55.0) in the nailing group. Patients in the plating and nailing groups were followed up for 24.0 (12.0-60.0) and 27.8 (12.0-60.0) months. All patients were followed for a minimum of 12 months. No significant differences were observed between the groups in terms of age, sex, or duration of follow-up (p > 0.05) Comparison of the pre- and post-operative mLDFA, aLDFA, MAD, length of hospital stay, and duration of surgery between the plating group and nailing group, no significant difference was observed between the groups (p > 0.05). However, patients treated with retrograde IMN had significantly better post-operative results in terms of the KOOS and range of motion of the knee according to plating group (p < 0.05).

CONCLUSION

Retrograde IMN does not provide a radiological advantage over the LISS plating technique for valgus deformity but retrograde IMN and correction offered better functional results in cases of femoral valgus deformity than did the LISS plating method.

Motion Predicts Clinical Callus Formation: Construct-Specific Finite Element Analysis of Supracondylar Femoral Fractures

BACKGROUND

Mechanotransduction is theorized to influence fracture-healing, but optimal fracture-site motion is poorly defined. We hypothesized that three-dimensional (3-D) fracture-site motion as estimated by finite element (FE) analysis would influence callus formation for a clinical series of supracondylar femoral fractures treated with locking-plate fixation.

METHODS

Construct-specific FE modeling simulated 3-D fracture-site motion for sixty-six supracondylar femoral fractures (OTA/AO classification of 33A or 33C) treated at a single institution. Construct stiffness and directional motion through the fracture were investigated to assess the validity of construct stiffness as a surrogate measure of 3-D motion at the fracture site. Callus formation was assessed radiographically for all patients at six, twelve, and twenty-four weeks postoperatively. Univariate and multivariate linear regression analyses examined the effects of longitudinal motion, shear (transverse motion), open fracture, smoking, and diabetes on callus formation. Construct types were compared to determine whether their 3-D motion profile was associated with callus formation.

RESULTS

Shear disproportionately increased relative to longitudinal motion with increasing bridge span, which was not predicted by our assessment of construct stiffness alone. Callus formation was not associated with open fracture, smoking, or diabetes at six, twelve, or twenty-four weeks. However, callus formation was associated with 3-D fracture-site motion at twelve and twenty-four weeks. Longitudinal motion promoted callus formation at twelve and twenty-four weeks (p = 0.017 for both). Shear inhibited callus formation at twelve and twenty-four weeks (p = 0.017 and p = 0.022, respectively). Titanium constructs with a short bridge span demonstrated greater longitudinal motion with less shear than did the other constructs, and this was associated with greater callus formation (p < 0.001).

CONCLUSIONS

In this study of supracondylar femoral fractures treated with locking-plate fixation, longitudinal motion promoted callus formation, while shear inhibited callus formation. Construct stiffness was found to be a poor surrogate of fracture-site motion. Future implant design and operative fixation strategies should seek to optimize 3-D fracture-site motion rather than rely on surrogate measures such as axial stiffness.

The effects of distal interlocking screws on torsional stability in three-part intertrochanteric hip fractures

OBJECTIVE

Many surgeons currently use long cephomedullary nails for the treatment of intertrochanteric fractures. The optimal indications for deploying distal interlocks are still debatable. This study examined the torsional biomechanical properties of 3-part intertrochanteric femur fractures in a cadaveric bone model using two different distal fixation strategies, an unlocked long cephalomedullary nail versus a dynamically locked nail. Our hypothesis is that a long cephalomedullary nail does not require distal locking fixation when used for treatment of a 3-part intertrochanteric fracture.

METHODS

Five matched pairs of cadaveric femora were randomly assigned to one of two distal fixation treatment groups; a single distal interlock screw placed in the dynamic orientation or no distal fixation. A 3-part intertrochanteric fracture was produced. Specimens were potted and mounted in a double gimbal fixture facilitating unconstrained motion in the sagittal and coronal planes. Specimens were cyclically loaded dynamically in both internal and external rotation. Range of motion, internal and external rotation stiffness, torsion stiffness, torsion yield and ultimate torsion magnitude were calculated.

RESULTS

The samples instrumented with a distal locking screw reported statistically greater external rotational stiffness than the unlocked samples in nondestructive testing. The results of the destructive data demonstrated no statistical difference between the locked and unlocked group with regard to yield torque (p = 0.282), peak torque (p = 0.340), stiffness (p = 0.220), displacement at yield torque (p = 0.0605), and displacement at peak torque (p = 0.280).

CONCLUSION

Distal locking of a long cephalomedullary nail increases the stiffness of the nail-femur construct in a 3-part biomechanical fracture model. However, our testing illustrates that an unlocked construct will tolerate at least equal stress before catastrophic failure in a torsional loading model.

Retrograde intramedullary nailing for the treatment of femoral medial condyle fracture nonunion

An unicondylar fracture of the femur is uncommon and of the medial condyle more so. Open reduction and internal fixation of these fractures is most commonly performed with screws or plate and screws. Secure bone fixation is compromised by osteoporosis in elderly patients; additional measures may be required. We report the case of an elderly osteoporotic patient with a medial condyle fracture nonunion treated successfully through retrograde intramedullary nailing. A 78-year-old osteoporotic woman suffered medial condyle fracture of the femur 9 months before visiting our hospital. She had been treated conservatively, and the fracture demonstrated a complete nonunion with gross instability. The edge fragments appeared sclerotic, and the nonunion site was accompanied by a bony defect. Although fixation by a plate and screw is the standard method for the treatment of such fracture, we judged that stability would be difficult to achieve with this method due to the accompanying bony defect and osteoporosis. Thus, we performed open reduction and fixation by retrograde intramedullary nailing with the use of "condyle screw and nut" system, followed by bone grafting. Bony union was successfully obtained. The stability and range of motion of the knee were recovered, and the patient regained the ability to walk. We suggest the unique application of retrograde intramedullary nailing with condyle screw and nut for the treatment of specific, complex cases of femoral medial condyle fracture.

Internal fixation of osteoporotic fractures

Osteoporosis leads to bone fragility and increased risk of fracture. Despite advances in diagnosis and treatment, the prevalence continues to rise. Osteoporotic fracture treatment has a unique set of difficulties related to poor bone quality and traditional approaches, and implants may not perform well. Fixation failure and repeat surgery are poorly tolerated and highly undesirable in this patient population. This review illustrates the most recent updates in internal fixation, implant design, and surgical theory regarding treatment of patients with osteoporotic fractures.

A biomechanical comparison of locked and unlocked long cephalomedullary nails in a stable intertrochanteric fracture model

OBJECTIVES

This study compared the torsional properties of stable intertrochanteric femur fractures in a cadaveric bone model using 2 different distal fixation strategies: unlocked long cephalomedullary nailing versus dynamically locked nailing.

METHODS

Fourteen matched pairs of cadaveric femora were randomly assigned to 1 of 2 distal fixation treatment groups: a single distal interlock screw placed in the dynamic orientation or no distal screw fixation. A stable 2-part intertrochanteric fracture was produced. Specimens were potted and mounted in a double gimbal fixture, facilitating unconstrained motion in the sagittal and coronal planes. Specimens were cyclically loaded dynamically in both internal and external rotation. Range of motion, internal and external rotation stiffness, torsion stiffness, torsion yield, and ultimate torsion magnitude were calculated.

RESULTS

The samples instrumented with a distal locking screw reported statistically significantly greater internal (1.54 ± 0.81 N·m per degree vs. 1.08 ± 0.35 N·m per degree; P = 0.026) and external rotational stiffness (1.42 ± 0.72 N·m per degree vs. 0.86 ± 0.36 N·m per degree; P = 0.009). Samples with locked distal fixation were statistically stiffer and displayed statistically less displacement at the yield and peak torque. The yield torque was statistically significantly higher in the samples without distal fixation (14.2 ± 3.3 N·m per degree vs. 10.6 ± 3.8 N·m per degree; P = 0.037). The peak torque was comparable between locked and unlocked samples (15.0 ± 4.6 N·m per degree vs. 16.2 ± 4.2 N·m per degree; P = 0.492).

CONCLUSIONS

Distal locking of femoral intramedullary nails increases the stiffness of the nail-femur construct. Unlocked samples displayed statistically significant higher yield torque while maintaining comparable peak torque as the locked samples. This study indicates that treating stable intertrochanteric fractures with unlocked long intramedullary nails may be an acceptable option, although further clinical study will be needed to test this assertion.

Implant augmentation: adding bone cement to improve the treatment of osteoporotic distal femur fractures: a biomechanical study using human cadaver bones

The increasing problems in the field of osteoporotic fracture fixation results in specialized implants as well as new operation methods, for example, implant augmentation with bone cement. The aim of this study was to determine the biomechanical impact of augmentation in the treatment of osteoporotic distal femur fractures.Seven pairs of osteoporotic fresh frozen distal femora were randomly assigned to either an augmented or nonaugmented group. In both groups, an Orthopaedic Trauma Association 33 A3 fractures was fixed using the locking compression plate distal femur and cannulated and perforated screws. In the augmented group, additionally, 1 mL of polymethylmethacrylate cement was injected through the screw. Prior to mechanical testing, bone mineral density (BMD) and local bone strength were determined. Mechanical testing was performed by cyclic axial loading (100 N to 750 N + 0.05N/cycle) using a servo-hydraulic testing machine.As a result, the BMD as well as the axial stiffness did not significantly differ between the groups. The number of cycles to failure was significantly higher in the augmented group with the BMD as a significant covariate.In conclusion, cement augmentation can significantly improve implant anchorage in plating of osteoporotic distal femur fractures.

Effect of distal interlock fixation in stable intertrochanteric fractures

The objective of this study was to evaluate the torsion stiffness of locked and unlocked distal fixation of long cephalomedullary nail constructs, in both a fresh fracture and healed, stable intertrochanteric fracture model. Samples were tested in both internal and external rotation (0±3 Nm) for a duration of 10 cycles. Each femur was tested without instrumentation (intact femur), with instrumentation and no fracture (healed intertrochanteric fracture), and with instrumentation with an osteotomy creating a stable intertrochanteric fracture (fresh fracture). All specimens were instrumented with a long cephalomedullary nail. A distal interlock was placed in the dynamic position in 1 femur, and the other femur of the matched pair was left unlocked. Mean external (ER) and internal (IR) rotation stiffness for intact femurs without instrumentation (ER, 2.1±0.5 Nm/degree; IR, 2.2±0.5 Nm/degree) was statistically stiffer (P<.05 for all) compared with fresh fractured locked (ER, 1.1±0.2 Nm/degree; IR, 1.1±0.3 Nm/degree) and fresh fractured unlocked (ER, 0.9±0.3 Nm/degree; IR, 1.0±0.2 Nm/degree) samples. Similarly, healed locked (ER, 2.5±0.2 Nm/degree; IR, 2.8±0.1 Nm/degree) and healed unlocked (ER, 2.5±0.5 Nm/degree; IR, 2.4±0.3 Nm/degree) samples had statistically higher stiffness compared with fresh fractured treatments. These results suggest that the unlocked distal constructs provide similar torsional strength compared with locked fixation in these models.