Aims

The incidence of atypical femoral fractures (AFFs) continues to increase. However, there are currently few long-term studies on the complications of AFFs and factors affecting them. Therefore, we attempted to investigate the outcomes, complications, and risk factors for complication through mid-term follow-up of more than three years.

Objectives. The use of two implants to manage concomitant ipsilateral femoral shaft and proximal femoral fractures has been indicated, but no studies address the relationship of dynamic hip screw (DHS) side plate screws and the intramedullary nail where failure might occur after union. This study compares different implant configurations in order to investigate bridging the gap between the distal DHS and tip of the intramedullary nail. Methods. A total of 29 left synthetic femora were tested in three groups: 1) gapped short nail (GSN); 2) unicortical short nail (USN), differing from GSN by the use of two unicortical bridging screws; and 3) bicortical long nail (BLN), with two angled bicortical and one unicortical bridging screws. With these findings, five matched-pairs of cadaveric femora were tested in two groups: 1) unicortical long nail (ULN), with a longer nail than USN and three bridging unicortical screws; and 2) BLN. Specimens were axially loaded to 22.7 kg (50 lb), and internally rotated 90°/sec until failure. Results. For synthetic femora, a difference was detected between GSN and BLN in energy to failure (p = 0.04) and torque at failure (p = 0.02), but not between USN and other groups for energy to failure (vs GSN, p = 0.71; vs BLN, p = 0.19) and torque at failure (vs GSN, p = 0.55; vs BLN, p = 0.15). For cadaveric femora, ULN and BLN performed similarly because of the improvement provided by the bridging screws. Conclusions. Our study shows that bicortical angled screws in the DHS side plate are superior to no screws at all in this model and loading scenario, and suggests that adding unicortical screws to a gapped construct is probably beneficial

Aims. It is imperative to understand the risks of operating on urgent cases during the COVID-19 (SARS-Cov-2 virus) pandemic for clinical decision-making and medical resource planning. The primary aim was to determine the mortality risk and associated variables when operating on urgent cases during the COVID-19 pandemic. The secondary objective was to assess differences in the outcome of patients treated between sites treating COVID-19 and a separate surgical site. Methods. The primary outcome measure was 30-day mortality. Secondary measures included complications of surgery, COVID-19 infection, and length of stay. Multiple variables were assessed for their contribution to the 30-day mortality. In total, 433 patients were included with a mean age of 65 years; 45% were male, and 90% were Caucasian. Results. Overall mortality was 7.6% for all patients and 15.9% for femoral neck fractures. The mortality rate increased from 7.5% to 44.2% in patients with fracture neck of femur and a COVID-19 infection. The COVID-19 rate in the 30-day postoperative period was 11%. COVID-19 infection, age, and Charlson Comorbidity Index were independent risk factor for mortality. Conclusion. There was a significant risk of contracting COVID-19 due to being admitted to hospital. Using a site which was not treating COVID-19 respiratory patients for surgery did not identify a difference with respect to mortality, nosocomial COVID-19 infection, or length of stay. The COVID-19 pandemic significantly increases perioperative mortality risk in patients with fractured neck of femora but patients with other injuries were not at increased risk. Cite this article: Bone Jt Open 2021;2(5):330–336

Aim. The aim of this study was to determine whether the absence of periosteal reaction on plain radiographs was predictive of exchange nail failure in lower limb diaphyseal fracture non-unions. Methods. A consecutive cohort of 20 femora and 35 tibiae undergoing exchange nailing for diaphyseal aseptic (n=39) and septic (n=16) fracture non-union at a single centre from 2003 to 2010. Multiple causes of non-union were found in 29 patients (53%) with infection present in 16 cases (29.1%). Of this cohort 49 fracture non-unions had complete radiographic records (19 femora and 30 tibiae) allowing evaluation of the periosteal callus. The primary outcome was the number of number of revision procedures required to achieve union. Failure was defined was as the requirement of >two revision procedures to achieve union. Results. The absence of periosteal callus from the fracture site on all four cortices conferred a relative risk ratio (RRR) 5.00 (p=0.006) of exchange nail failure in septic fracture non-unions. Receiver operator characteristic curve analysis of number of cortices with periosteal reaction for predicting exchange nail (>two exchange nail procedures) failure in both septic and aseptic cases found an area under the curve of 0.79 (95% confidence interval 0.675–0.904, p<0.0001). The complete absence of callus within 5 mm of the fracture site had a 75% chance of requiring 3 or more exchange nails to obtain union. Conversely the presence periosteal callus on at least one cortex within 5mm of the fracture site had a 100% chance the fracture would unite following 1 or 2 exchange nail procedures. Conclusion. Careful radiographic analysis of lower limb diaphyseal non-union should be undertaken before exchange nailing. The absence of periosteal reaction on plain radiographs in septic fracture non-union is predictive of exchange nail failure

Common cell based strategies for treating bone defects require time-consuming and expensive isolation and expansion of autologous cells. We developed a novel expedited technology creating gene activated muscle grafts. We hypothesized that BMP-2 activated muscle grafts provide healing capabilities comparable to autologous bone grafting, the clinical gold standard. Two male, syngeneic Fischer 344 rats served as tissue donors. Muscle tissue was harvested from hind limbs and incubated with an adenoviral vector carrying the cDNA encoding BMP-2. Bone tissue was harvested from the iliac crest. Segmental bone defects were created in the right femora of 12 rats and were filled with either BMP-2 activated muscle tissue or bone grafts. After 8 weeks, femora were evaluated by radiographs, microCT, and biomechanical tests. BMP-2 activated muscle grafts and autologous bone grafts resulted in complete mineralization and healing, as documented by radiographs and microCT. Bone volume in the muscle graft defects (33+/-12mm3) was similar to autologous bone graft defects (39+/-5mm3). Torque at failure of the two groups was statistically indistinguishable (240+/-115 Nmm vs. 232+/-108Nmm). In previous experiments we demonstrated that the large segmental defect model in this study will not heal with either empty defects or non-activated muscle grafts. Our findings therefore demonstrate that BMP-2 gene activation of muscle tissue effectively stimulates defect healing similar to autologous bone grafts

MicroRNAs (miRNAs ) are small non-coding RNAs that regulate gene expression. We hypothesised that the functions of certain miRNAs and changes to their patterns of expression may be crucial in the pathogenesis of nonunion. Healing fractures and atrophic nonunions produced by periosteal cauterisation were created in the femora of 94 rats, with 1:1 group allocation. At post-fracture days three, seven, ten, 14, 21 and 28, miRNAs were extracted from the newly generated tissue at the fracture site. Microarray and real-time polymerase chain reaction (PCR) analyses of day 14 samples revealed that five miRNAs, miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p, were highly upregulated in nonunion. Real-time PCR analysis further revealed that, in nonunion, the expression levels of all five of these miRNAs peaked on day 14 and declined thereafter. . Our results suggest that miR-31a-3p, miR-31a-5p, miR-146a-5p, miR-146b-5p and miR-223-3p may play an important role in the development of nonunion. These findings add to the understanding of the molecular mechanism for nonunion formation and may lead to the development of novel therapeutic strategies for its treatment. Cite this article: Bone Joint J 2015; 97-B:1144–51

Background. Continual implant stability is an important factor for the long-term success of cementless hip replacements. The increasing lifespan of patients causes a higher frequency of osteoporosis which may result in implant loosening due to bone loss. This study aimed to evaluate stability of long living implants in patients with advanced age. Patients and methods. Nine cementless stems made of Titanium-alloy including adjacent bone tissue obtained post mortem were evaluated by radiologic-microradigraphical, histological and morphometrical analysis. The percentage of the surface area covered by bone (BICI=bone implant contact index) was determined. The age of seven women and two men ranged between 81 and 92 years. The time in situ ranged between 10 and 20 years. From the entire length of the femora bearing implants 5 transverse segments were excised, dehydrated, embedded in methylmethacrylate. After the grinding procedure, the sections were evaluated by light microscopy and morphometrical analysis. The autopsy findings were recorded. Atherosclerosis and their related diseases were evident in all cases. Results. The femora of all female patients revealed features of high bony atrophy with concomitant transformation of the corticalis into spongy bone, whereas in male patients minor to moderate atrophic bone changes in the proximal femoral area without implication of the corticalis could be observed. All of the cementless stems made of Titanium-alloy showed osteointegration. The stabilization of the implant resulted in the forceps-like encasement of the edges of the implant within the cortical anchoring and by the development of compensatory bony hypertrophy. The BICI ranged between 35 und 63 percent. Conclusion. Elderly patients provided with cementless hip replacments revealed stable implants in spite of marked bone atrophy and an implantation period up to 20 years. Simultaneously, severe atherosclerosis and their related diseases, which may contribute to bone loss, were evident. The present findings may result from the favoring properties of cementless endoprostheses made of titanium alloy, cortical prosthesis anchoring, and self regulating bone processes. Pharmacologic and therapeutic consequences together with geriatric assessment should be required to preserve functionality and mobility

The purpose of this study was to describe the anatomical distribution and incidence of fatigue injuries of the femur in physically-active young adults, based upon MRI studies. During a period of 70 months, 1857 patients with exercise-induced pain in the femur underwent MRI of the pelvis, hips, femora, and/or knees. Of these, 170 patients had a total of 185 fatigue injuries, giving an incidence of 199 per 100 000 person-years. Bilateral injuries occurred in 9% of patients. The three most common sites affected were the femoral neck (50%), the condylar area (24%) and the proximal shaft (18%). A fatigue reaction was seen in 57%, and a fracture line in 22%. There was a statistical correlation between the severity of the fatigue injury and the duration of pain (p = 0.001). The location of the pain was normally at the site of the fatigue injury. Fatigue injuries of the femur appear to be relatively common in physically-active patients

Despite its clinical significance, metaphyseal fracture healing has received little attention in research and experimental models have been limited. In particular it is not known to what extent the mechanical environment plays a role in metaphyseal fracture healing. Recently, a new murine internal fixation plate has been developed to stabilise fractures in the distal femur under highly standardised conditions. Goal of the current study was to modify this design, in order to be able to evaluate the influence of the fixator bending stiffness on metaphyseal fracture healing in mice. Adapting the existing single body design, resulting in low flexibility fixation, two new plates were developed with a decreased bending stiffness of approximately 65% and 45% of the original implant (100%). Pilot experiments were performed on 54 animals, whereas the mice were sacrificed and fracture healing assessed radiologically and biomechanically after 14 and 28 days. MicroCT evaluation confirmed that the osteotomy was created in the trabecular, metaphyseal bone of the distal mouse femora. All bones showed progressive fracture healing over time, with decreased implant stiffness leading to increased periosteal callus formation. These implants represent an important new research tool to study molecular and genetic aspects of metaphyseal fracture healing in mice under standardized mechanical conditions, in order to improve clinical treatment in challenging situations, such as in osteoporotic bone

Clinical evidence that patients with type 2 diabetes mellitus (T2DM) have increased risk of fractures is reported. Furthermore, thiazolidinediones, used to treat T2DM increases the risk of secondary osteoporosis & subsequent fractures. The osteogenic potency of metformin is reported in vitro, few studies have investigated the effects of metformin on bone mass and fracture healing in vivo. We aimed to investigate the effects of metformin on fracture healing in vivo. Method. 20 female Wistar rats aged 3 months were randomly divided in two groups, one group receiving saline, the other group receiving metformin administered orally via the drinking water at a concentration of 2mg/ml. After 4 weeks of metformin treatment, a mid-diaphyseal, open External fixation fracture was performed. Rats were sacrified 4 weeks later. Right contralateral tibia and left osteotomised femora were excised, bone architecture analysed by micro-CT in the right tibia. Results. No significant differences were noted between the two groups. Fracture callus volume and mineral content after 4 weeks were similar in metformin and saline groups. Discussion Our results indicate that while metformin has no adverse effects on bone, it does not promote bone mass, as suggested by in vitro studies. This confirms clinical data which have not shown direct links between metformin and decreased fracture risk

Background. Femoroacetabular impingement due to a reduced femoral head-neck-offset or excessive acetabular coverage will lead to early cartilage lesions of the hip joint. The purpose of the present study was to analyze the relationship between the extent of bony deformity and the presence and extent of cartilage lesions in femoroacetabular impingement. Methods. On the radiographs of 92 hip joints in 86 patients with a mean age of 36.5 ± 9.2 years who were operated on for with femoroacetabular impingement by surgical hip dislocation, the acetabular index of the weight-bearing zone, the center-edge-angle, the inclination of the acetabulum, the lateral-head-extrusion-index, retroversion signs of the acetabulum, the neck-shaft-angle, asphericity, superior and anterior alpha angles, and superior and anterior offset and offset ratios were assessed and correlated to the presence and extent of chondromalazia. Results. Acetabular chondromalazia was found in 60 hip joints. Full-thickness delamination of the acetabular cartilage was present in 42 of these hips with an average size of 1.1 ± 0.5 cm2. Femoral-sided chondromalazia was found in 9 hip joints. Hip joints with chondromalazia had a lower center-edge-angle (p = 0.014) and anterior offset ratio (p = 0.028) and a higher lateral-head-extrusion-index (p = 0.029). Hip joints with acetabular cartilage delamination had a significantly lower center-edge-angle (p = 0.012) and anterior offset (p = 0.03) and a significantly higher lateral-head-extrusion-index (p = 0.001) and superior (p = 0.006) and anterior alpha angles (p = 0.003). Conclusions. Marked cam-type femoral deformity and lesser coverage of the femoral head are associated with the acetabular cartilage lesions, arousing suspicion to the assumption that a large lateral aperture of the acetabulum abets proximal femora with cam-type deformity to inflict cartilage damage in femoroacetabular impingement

Background. In poliomyelitis; hand to knee gait is the sum of quadriceps weakness and fixed knee flexion deformity. Limb shortening is another added problem. Usually, each problem is attacked separately; with variable end results and complication rates for each procedure. Patients and methods. 22 patients (16–46 y.); with poliomyelitis with hand to knee gait due to fixed knee flexion deformity of mild to moderate degree (10–400); and limb shortening of 4.5–9.5 cm., were managed simultaneously by a single operation. A distal femoral metaphyseal anterior closing wedge (recurvatum) corrective osteotomy was done to treat acutely the fixed knee flexion deformity(and subsequently hand to knee gait). A modified Wagner or Orthofix frame was applied as a mono-plane mono-axial lengthening device to stabilize the osteotomy and to lengthen the short limb. Lengthening was started in all cases two weeks post-operatively. Results. All cases showed full correction of the deformity with elimination of the hand to knee gait problem and all showed - the desired - limb length equalization. The femora were lengthened to an average of 6.4 cm.(= 21% of original femoral bone length), range of lengthening was: 4–9 cm. (= 11–26%). The average healing index was 37 days per centimeter (with a range of 31 to 53 days per centimeter.). Conclusion. Simultaneous management of hand to knee and limb shortening could be achieved by a single osteotomy which is used to extend the knee acutely and for distraction two weeks later using a mono-lateral frame. Results were good, complications were few and accepted and the procedure is well tolerated by the patients

Introduction. Periprosthetic femur fractures are a serious complication after hip replacement surgery. In an aging population these fractures are becoming more and more common. Open reduction and plate osteosynthesis is one of the available treatment options. Objective. To investigate hip stem stability and cement mantle integrity under cyclic loading conditions after plate fixation with screws perforating the cement in the proximal fragment. Methods. Polished tapered hip stems were implanted in 16 biomechanical testing femora with Palacos cement (3rd generation technique) according to the manufacturer's recommendations. 8 testing bones were osteotomised distal to the stem representing the fracture group (Vancouver Type C). The osteotomy was fixed with a polyaxial locking plate, the other 8 specimens served as a control group. The specimens were tested in a biaxial material testing machine under axial compression (including adduction and torsion moments) for 100.000 cycles at physiological loads. Stem subsidence was measured in 3 planes with a stereoscopic image correlation system during the tests. Subsequently the sliced and crack dyed specimens were investigated microscopically for cement cracks. Results. In the control group no specimen failed during testing. There were no statistically significant differences in stem subsidence along the longitudinal axis (control group mean ± SD −15.4 ± 12.2 μm, fracture group −14.1 ± 13.1 μm). In the fracture group two specimens fractured through the most proximal screw hole after 74.000 and 80.000 cycles. Overall 15 out of 36 screws in the proximal fragment had direct stem contact. No cement cracks were detected in the sliced specimens in both groups. Conclusion. Drilling the cement mantle and placing screws in the cement did not increase stem subsidence under cyclic loading. No cracks or cement mantle failure were observed. Large screw diameters proximally weaken the lateral cortex resulting in tension failure of the bone. Plate fixation of a periprosthetic femoral fracture with a stable, cemented prosthesis does not lead to early cement mantle failure

Introduction. Malrotation following total knee replacement is directly related to poor outcome. The knowledge of proximal and distal rotational axes and angles of the femur is therefore of high importance. The aim of the study was to determine whether the most used proximal and distal femoral angles; femoral anteversion angle (FAA) and posterior condylar angle (PCA) were different within individuals, between right, left and gender. As well, we studied whether the “inferior condylar angle” is correlated to the PCA and therefore useful in determining the rotation of the distal femur. Material and Methods. From 36 cadavers the femora were obtained and after removing the soft tissue a Computed Tomography (CT) scan was made. Three angles were measured: (i) the FAA between femoral columnar line (FHNL) and posterior condylar line (PCL), (ii) the PCA between anatomical transepicondylar line (TEL) and PCL, (iii) the inferior condylar angle (ICA) between the TEL and inferior condylar line (ICL). Statistical analysis of comparative relationships between the different angles was examined by calculating correlation coefficients and a paired t-test. Results. The mean FAA, PCA and ICA for the whole group were respectively 12.0 degrees (range 0.2–31.6, SD 8.3, 95% CI 9.6–14.4), 4.8 degrees (range 0.9–9.6, SD 2.3, 95% CI 4.1–5.4) and 4.5 degrees (range 0.1–9.8, SD 2.1, 95% CI 3.9–5.1). A strong correlation of the FAA was found within the total group and left versus right (r = 0.82; p = 0.00). A weaker relationship was found for the total group of the PCA measurements (r = 0.59; p = 0.00). When FAA compared to the PCA subdivided in only sexes, there is a weak correlation for the female group (r = 0.54; p = 0.00) Despite the small mean difference of the mean ICA and PCA, there was no correlation between these two angles. Conclusion. Considering the weak correlation of the FAA and PCA within the group but also individuals, the importance of development of more individual approaches for determining the optimal rotation of the components in total knee surgery is essential. As a result, one should be aware that the widely used, current guidelines for knee rotation of 3 degrees of external rotation in placing total knee arthroplasties shows variation between individuals. A more individual approach in total knee arthroplasty seems essential for future knee prosthesis implantations

Aims

Dual plating of distal femoral fractures with medial and lateral implants has been performed to improve construct mechanics and alignment, in cases where isolated lateral plating would be insufficient. This may potentially compromise vascularity, paradoxically impairing healing. This study investigates effects of single versus dual plating on distal femoral vascularity.

It is becoming increasingly common for a patient to have ipsilateral hip and knee replacements. The inter-prosthetic (IP) distance, the distance between the tips of hip and knee prostheses, has been thought to be associated with an increased risk of IP fracture. Small gap distances are generally assumed to act as stress risers, although there is no real biomechanical evidence to support this.

The purpose of this study was to evaluate the influence of IP distance, cortical thickness and bone mineral density on the likelihood of an IP femoral fracture.

A total of 18 human femur specimens were randomised into three groups by bone density and cortical thickness. For each group, a defined IP distance of 35 mm, 80 mm or 160 mm was created by choosing the appropriate lengths of component. The maximum fracture strength was determined using a four-point bending test.

The fracture force of all three groups was similar (p = 0.498). There was a highly significant correlation between the cortical area and the fracture strength (r = 0.804, p <  0.001), whereas bone density showed no influence.

This study suggests that the IP distance has little influence on fracture strength in IP femoral fractures: the thickness of the cortex seems to be the decisive factor.

Cite this article: Bone Joint J 2014;96-B:1378–84.

We investigated a new intramedullary locking nail that allows the distal interlocking screws to be locked to the nail. We compared fixation using this new implant with fixation using either a conventional nail or a locking plate in a laboratory simulation of an osteoporotic fracture of the distal femur. A total of 15 human cadaver femora were used to simulate an AO 33-A3 fracture pattern. Paired specimens compared fixation using either a locking or non-locking retrograde nail, and using either a locking retrograde nail or a locking plate. The constructs underwent cyclical loading to simulate single-leg stance up to 125 000 cycles. Axial and torsional stiffness and displacement, cycles to failure and modes of failure were recorded for each specimen. When compared with locking plate constructs, locking nail constructs had significantly longer mean fatigue life (75 800 cycles (sd 33 900) vs 12 800 cycles (sd 6100); p = 0.007) and mean axial stiffness (220 N/mm (sd 80) vs 70 N/mm (sd 18); p = 0.005), but lower mean torsional stiffness (2.5 Nm/° (sd 0.9) vs 5.1 Nm/° (sd 1.5); p = 0.008). In addition, in the nail group the mode of failure was either cut-out of the distal screws or breakage of nails, and in the locking plate group breakage of the plate was always the mode of failure. Locking nail constructs had significantly longer mean fatigue life than non-locking nail constructs (78 900 cycles (sd 25 600) vs 52 400 cycles (sd 22 500); p = 0.04).

The new locking retrograde femoral nail showed better stiffness and fatigue life than locking plates, and superior fatigue life to non-locking nails, which may be advantageous in elderly patients.

Cite this article: Bone Joint J 2014;96-B:114–21.

Aims

The aim of this paper is to review the evidence relating to the anatomy of the proximal femur, the geometry of the fracture and the characteristics of implants and methods of fixation of intertrochanteric fractures of the hip.

Systemic antibiotics reduce infection in open fractures. Local delivery of antibiotics can provide higher doses to wounds without toxic systemic effects. This study investigated the effect on infection of combining systemic with local antibiotics via polymethylmethacrylate (PMMA) beads or gel delivery.

An established Staphylococcus aureus contaminated fracture model in rats was used. Wounds were debrided and irrigated six hours after contamination and animals assigned to one of three groups, all of which received systemic antibiotics. One group had local delivery via antibiotic gel, another PMMA beads and the control group received no local antibiotics. After two weeks, bacterial levels were quantified.

Combined local and systemic antibiotics were superior to systemic antibiotics alone at reducing the quantity of bacteria recoverable from each group (p = 0.002 for gel; p = 0.032 for beads). There was no difference in the bacterial counts between bead and gel delivery (p = 0.62).

These results suggest that local antibiotics augment the antimicrobial effect of systemic antibiotics. Although no significant difference was found between vehicles, gel delivery offers technical advantages with its biodegradable nature, ability to conform to wound shape and to deliver increased doses. Further study is required to see if the gel delivery system has a clinical role.

Cite this article: Bone Joint J 2015;97-B:1423–7.

Several bisphosphonates are now available for the treatment of osteoporosis. Porous hydroxyapatite/collagen (HA/Col) composite is an osteoconductive bone substitute which is resorbed by osteoclasts. The effects of the bisphosphonate alendronate on the formation of bone in porous HA/Col and its resorption by osteoclasts were evaluated using a rabbit model. Porous HA/Col cylinders measuring 6 mm in diameter and 8 mm in length, with a pore size of 100 μm to 500 μm and 95% porosity, were inserted into a defect produced in the lateral femoral condyles of 72 rabbits. The rabbits were divided into four groups based on the protocol of alendronate administration: the control group did not receive any alendronate, the pre group had alendronate treatment for three weeks prior to the implantation of the HA/Col, the post group had alendronate treatment following implantation until euthanasia, and the pre+post group had continuous alendronate treatment from three weeks prior to surgery until euthanasia. All rabbits were injected intravenously with either saline or alendronate (7.5 μg/kg) once a week. Each group had 18 rabbits, six in each group being killed at three, six and 12 weeks post-operatively. Alendronate administration suppressed the resorption of the implants. Additionally, the mineral densities of newly formed bone in the alendronate-treated groups were lower than those in the control group at 12 weeks post-operatively. Interestingly, the number of osteoclasts attached to the implant correlated with the extent of bone formation at three weeks.

In conclusion, the systemic administration of alendronate in our rabbit model at a dose-for-weight equivalent to the clinical dose used in the treatment of osteoporosis in Japan affected the mineral density and remodelling of bone tissue in implanted porous HA/Col composites.