Aims. This study reviews the use of a titanium mesh cage (TMC) as an adjunct to intramedullary nail or plate reconstruction of an extra-articular segmental long bone defect. Patients and Methods. A total of 17 patients (aged 17 to 61 years) treated for a segmental long bone defect by nail or plate fixation and an adjunctive TMC were included. The bone defects treated were in the tibia (nine), femur (six), radius (one), and humerus (one). The mean length of the segmental bone defect was 8.4 cm (2.2 to 13); the mean length of the titanium mesh cage was 8.3 cm (2.6 to 13). The clinical and radiological records of the patients were analyzed retrospectively. Results. The mean time to follow-up was 55 months (12 to 126). Overall, 16 (94%) of the patients achieved radiological filling of their bony defect and united to the native bone ends proximally and distally, resulting in a functioning limb. Complications included device failure in two patients (12%), infection in two (12%), and wound dehiscence in one (6%). Four patients (24%) required secondary surgery, four (24%) had a residual limb-length discrepancy, and one (6%) had a residual angular limb deformity. Conclusion. A titanium mesh cage is a useful adjunct in the treatment of an extra-articular segmental defect in a long bone. Cite this article: Bone Joint J 2018;100-B:646–51

Between 1996 and 2003 six institutions in the United States and France contributed a consecutive series of 234 fractures of the femur in 229 children which were treated by titanium elastic nailing. Minor or major complications occurred in 80 fractures. Full information was available concerning 230 fractures, of which the outcome was excellent in 150 (65%), satisfactory in 57 (25%), and poor in 23 (10%). Poor outcomes were due to leg-length discrepancy in five fractures, unacceptable angulation in 17, and failure of fixation in one. There was a statistically significant relationship (p = 0.003) between age and outcome, and the odds ratio for poor outcome was 3.86 for children aged 11 years and older compared with those below this age. The difference between the weight of children with a poor outcome and those with an excellent or satisfactory outcome was statistically significant (54 kg vs 39 kg; p = 0.003). A poor outcome was five times more likely in children who weighed more than 49 kg

A total of 20 patients with a depressed fracture of the lateral tibial plateau (Schatzker II or III) who would undergo open reduction and internal fixation were randomised to have the metaphyseal void in the bone filled with either porous titanium granules or autograft bone. Radiographs were undertaken within one week, after six weeks, three months, six months, and after 12 months. The primary outcome measure was recurrent depression of the joint surface: a secondary outcome was the duration of surgery. The risk of recurrent depression of the joint surface was lower (p < 0.001) and the operating time less (p < 0.002) when titanium granules were used. The indication is that it is therefore beneficial to use porous titanium granules than autograft bone to fill the void created by reducing a depressed fracture of the lateral tibial plateau. There is no donor site morbidity, the operating time is shorter and the risk of recurrent depression of the articular surface is less. . Cite this article: Bone Joint J 2015; 97-B:836–41

Introduction. The most common treatment options for fixation of osteoporotic distal femur fractures are retrograde nails and locking plates. There are proponents of more elastic titanium plates as well as more rigid steel plates; No clear superiority of one over the other has been established. We aimed to evaluate the mechanical differences between stainless steel and titanium locking plates in the fixation of distal femur fractures in osteoporotic bone. We hypothesized that due to its higher elasticity titanium locking plates can absorb more energy and are therefore less likely to “cut” into the bone compared to stainless steel locking plates resulting in improved metaphyseal osteoporotic fracture fixation. Methods. We used eight matched pairs of osteoporotic fresh-frozen human cadaveric femurs (age >70 years, all female). Within each pair we randomized one femur to be fitted with a Less Invasive Stabilization System (LISS-Titanium locking plate) and one with a Distal Locking Condylar Plate (DLCP-Stainless steel locking plate). A fracture model simulating an AO 33-A3 fracture was created (extraarticular comminuted fracture) and specimens were subsequently subjected to step-wise cyclic axial loading to failure. We used an advanced three dimensional tracking system (Polhemus Fastrak) to monitor the movement of the distal fragment relative to the real time distal plate position allowing us to evaluate distal implant cut-out. Results. During cyclic testing, seven of the eight pairs of matched femurs, the DLCP failed before the LISS plate (p=0.03). All constructs were able to withstand cyclical loading up to 800N. The overall plastic deformation as measured by the displacement of the Instron crosshead experienced by the titanium plate constructs was significantly lower compared to the stainless steel plate construct: The plastic deformation of the LISS plates was 39% lower compared to the Locking Condylar plates after cycle testing at 400 Newtons and 70% lower at 800N. Furthermore during the 800N cycle testing the LISS plating system showed a significantly lower rate of plastic deformation not only for the entire bone-implant construct, but also between the plate and the distal fragment than the locking condylar plate (=less distal implant cut-out). Conclusions. The use of a more advanced three dimensional tracking system, fresh-frozen osteoporotic matched human specimen and the ability to test all constructs to failure allowed us a more thorough comparison of titanium versus stainless steel implants compared to previous studies. The titanium locking plates provided an overall superior fixation of osteoporotic distal femur fractures with less distal implant cut-out, a better elastic recoil, and a slower rate of residual plastic deformation

We present our results of cementless total hip arthroplasty with a tapered, rectangular stem made of titanium-aluminum-niobium alloy. This implant is used since 1979 with only minor modifications. The design of the femoral component achieves primary stability through precision rasping and press-fit implantation. Between October 1986 and November 1987, two hundred consecutive patients (208 hips) underwent total hip arthroplasty with this tapered, rectangular stem. In all cases the acetabular component was a threaded cup made of titanium. At a minimum follow-up of twenty years eighty-seven patients were still alive. Sixty-seven patients (69 hips) were available for clinical and radiographic follow-up. The probability of survival of the stem was 0.96 (95% confidence interval, 0.91 to 0.98) and that of the cup was 0.72 (0.62 to 0.80). The probability of survival of both the stem and the acetabular component with revision for any reason as the end point was 0.71 (0.61 to 0.78). Two stems have been revised due to aseptic loosening. We found various degrees of osteolysis around the acetabular and femoral component (61,7%). At the time of the 20-year follow-up no stem was deemed at risk for loosening. The key findings of our twenty-year follow-up are the very low rate of revisions of the femoral component and the low rate of distal femoral osteolysis associated with this stem. Our data show that femoral fixation of the stem continues to be secure at a follow-up of twenty years

The osteointegration of a new three-dimensional reticular titanium material, Trabecular Titanium™, was assessed using a bilateral cancellous (distal femur, proximal tibia) and cortical (tibia diaphysis) bone drill hole model in 18 sheep. TT is a novel Ti6Al4V material characterized by a high open porosity and composed of multi-planar regular hexagonal cells. Two 5.0 mm diameter, 12 mm long cylinders (TT1 & TT2) of two different porosities (TT1:650 μm, TT2:1250 μm) were tested and compared to two solid predicate 5.0 mm diameter, 12 mm long Ti cylinders (PT1 & PT2) coated with porous Ti (PT1: vacuum-plasma spray coating; PT2: inert-gas shielding arc spray coating). Each implant type was surgically implanted at 4 separate locations in each sheep (16 implants per sheep). Three timepoints of 4, 16 and 52 weeks (n=6 sheep per timepoint) were used. Bone-implant interface was analyzed ex vivo by the determination of: 1) the shear strength (SS) measured during a push out test, 2) the percentage of bone in-growth (%B) using histomorphometry, 3) the bone apposition rate using fluorochrome labelling analysis and 4) the bone-implant contact using backscattered scanning electron microscopy (SEM). An ANOVA with a Bonferroni Post hoc test were used to detect differences between tested and predicate implants. P values 0.05 were considered significant. At 4 weeks, 5 out of the 6 TT1 could be pushed out of the cortical bone (COB) samples. The remaining TT1 collapsed during testing. All TT1 could be pushed of the cancellous bone (CAB) samples. Four out of the 6 TT2 could be pushed out of CAB and of the COB samples. At 16 and 52 weeks, only one TT1 and one TT2 could be pushed out of the bone samples, the remaining implants collapsed during testing. All the PTs were successfully pushed out at all timepoints. The mean %B of PT1 and PT2 did not significantly increase over time. For both materials, the mean %B ranged between 1.7% and 4.4% at 4 weeks and between 5.7% and 6.5% at 52 weeks. The mean %B of TT1 significantly increased over time in both COB (10.2% at 4 weeks, 46.2% at 16 weeks, 50.5% at 52 weeks) and CAB (5.8%, 23.9%, 24.3%). Similarly, the mean %B of TT2 significantly increased over time in both COB (7.8%, 48.6%, 65%) and CAB (4.5%, 24.1%, 38.6%). Bone apposition rates for the TT implants remained superior to 2 μm/day for the entire duration of the study. SEM showed an intimate bone-implant contact for all implant types at all timepoints. At 16 and 52 weeks, histomorphometry revealed an extensive osteointegration of the TT specimens. Bone-implant interface strength was so high for the TT implants that they could not be pushed out of the bone samples. The results of this study would indicate that the TT implants provide a good scaffold for bone in-growth

Engineered bone tissue to recreate the continuity of damaged skeletal segments is one of the field of interest of tissue engineering. Trabecular titanium has very good mechanical properties and high in vitro and in vivo biocompatibility: it can be used in biomedical applications to promote osteointegration demonstrating that it can be successfully used for regenerative medicine in orthopaedic surgery (1). Purpose of this investigation was to evaluate the behavior of adipose tissue derived stem cells (hASCs) cultured on scaffolds of Trabecular TitaniumTM (Lima-Lto) (TT). hASCs are considered to be multipotent mesenchymal stem cells that are easily induced to differentiate into functional osteoblasts both in vitro and in vivo (2). The hASCs were obtained from the subcutaneous adipose tissue of healthy donors during total hip replacement procedures after digestion with collagenase. They were seeded on monolayer and on the TT scaffolds, and incubated at 37 degrees C in 5% CO2 with osteogenic medium or control medium. The expression of bone-related genes using RT-PCR, time course of alkaline phosphatase activity and morphological investigation with Scanning Electron Microscopy (SEM) were performed to evaluate the osteogenic differentiation of hASCs. Alkaline phosphatase activity, marker of the differentiation toward the osteogenic pattern, was significantly higher in hASCs grown with osteogenic medium than in cells grown with control medium, both in monolayer and TT scaffolds; moreover, also alkaline phosphatase of hASCs grown on TT scaffolds in the presence of control medium increased with time, differently from that of cells grown on monolayer. The osteogenic differentiated hASCs expressed the bone-related genes type I collagen, osteocalcin, Runx-2 and alkaline phosphatase. SEM observations showed that hASCs differentiated toward osteoblast-like cells: they produced a big amount of extracellular matrix that covered the surface of the porous scaffolds with bridges between the pore walls. These data suggest that hASCs are able to adhere to TT scaffolds, to acquire an osteoblastic phenotype and to produce abundant extracellular matrix, with but also without osteogenic medium. We can therefore conclude that this material carries osteinductive properties being responsible of ostegenic differentiation; consequently, this scaffold/cells construct is effective to regenerate damaged tissue and to restore the function of bone tissue

The Thompson hemiarthroplasty is a common treatment option for acute neck of femur fractures in the elderly population. Our department noted a significant number of patients returning with thigh pain, radiographic loosening and femoral osteolysis following cemented implantation of the titanium alloy version of the Thompson hemiarthroplasty. We are not aware of any previous reports documenting complications specific to the titanium Thompson implant and a retrospective cohort study was therefore initiated following clinical governance approval. 366 titanium alloy Thompson prostheses were implanted for hip fracture treatment between 2017 and 2020. As of February 2023, 6 of these have been revised at our hospital. 5 were revised for symptomatic femoral osteolysis and 1 presented with an acute periprosthetic fracture. All revised cases were determined to be aseptic. 32 living patients were excluded from recall on compassionate grounds due to permanent nursing home residence. 47 living patients were identified of which 33 attended for xray. 28 deceased and/or nursing home resident patients who had pelvis x-rays in the previous 12 months were also included in the analysis. Including the 6 index hips already revised, a total of 61 hip xrays were analysed, of which 19 hips (31.1%) showed radiographic evidence of femoral osteolysis or loosening. We conclude that there is a concerning incidence of femoral osteolysis and implant loosening associated with the titanium Thompson implant. We have discontinued use of the implant and reported our experience to the MHRA. We encourage other Scottish Health-Boards who use this implant to consider enhanced follow-up

Aims. Osteopetrosis (OP) is a rare hereditary disease that causes reduced bone resorption and increased bone density as a result of osteoclastic function defect. Our aim is to review the difficulties, mid-term follow-up results, and literature encountered during the treatment of OP. Methods. This is a retrospective and observational study containing data from nine patients with a mean age of 14.1 years (9 to 25; three female, six male) with OP who were treated in our hospital between April 2008 and October 2018 with 20 surgical procedures due to 17 different fractures. Patient data included age, sex, operating time, length of stay, genetic type of the disease, previous surgery, fractures, complications, and comorbidity. Results. The mean follow-up period was 92.5 months (25 to 140). Bony union was observed in all of our patients. Osteomyelitis developed in two patients with femoral shaft fractures, and two patients had peri-implant stress fractures. Conclusion. Treatment of fractures in OP patients is difficult, healing is protracted, and the risk of postoperative infection is high. In children and young adults with OP who have open medullary canal and the epiphyses are not closed, fractures can be treated with surgical techniques such as intramedullary titanium elastic nail (TENS) technique or fixation with Kirschner (K)-wire. Cite this article: Bone Joint J 2020;102-B(8):1082–1087

The previous bioabsorbable plates have had several issues with regard to clinical usage for fractures. The aims of this study were to demonstrate the clinical results of novel bioabsorbable plates made of hydroxyapatite/poly-L-lactide and titanium plates for metacarpal fractures and to compare mechanical properties of them in a fracture model. The subjects were 33 metacarpal diaphyseal fractures of 27 consecutive patients treated with bioabsorbable plates. The mean age was 35.8 (17–78), 22 male and 5 female was included. The mean follow up period was 7.4months (2–14). All cases achieved bone union, and there were no complication especially for aseptic swelling etc. Furthermore, we compared the mechanical properties of bioabsorbable and titanium plates. There were no significant differences in 6 month postoperative clinical results including total range of active motion and % of the contralateral grip strength between patients receiving bioabsorbable and titanium plates. The bending strength and stiffness of one-third tubular bioabsorbable plate constructs were comparable with those of titanium plates for 1.5mm screws, and those of semi-tubular bioabsorbable plates were comparable with those of titanium plates for 2.0mm screws. The torsional strength of semi-tubular bioabsorbable plates was significantly greater than that of titanium plates for 2.0mm screws

Aims

Several previously identified patient-, injury-, and treatment-related factors are associated with the development of nonunion in distal femur fractures. However, the predictive value of these factors is not well defined. We aimed to assess the predictive ability of previously identified risk factors in the development of nonunion leading to secondary surgery in distal femur fractures.

Due to its popularity of intramedullary nails (IMN) high success rate, newer design (titanium) IMN system have been introduced to replace stainless steel system. However the stability provided by the titanium IMN. may not be adequate, there by influencing the union rate. We aimed to compare the results of both IMN systems via prospective clinical study and biomechanical testing using RSA. Biomechanical study. This study was done in an experimental set-up which consisted of a physically simulated femoral shaft fractures models fixed with a stainless steel (Russell Taylor) or Titanium (Trigen) IM nailing system. Two common fracture configurations with stimulated weight bearing conditions were used and the axis of fragment movements recorded. Clinical study. The data on two groups of patients were collected as part of a prospective cohort study. Details of the implant, such as size of nail, cross screw lengths, screw thickness, etc. was collected. Patients were followed up for a minimum of 4 months and details of clinical complications recorded. Biomechanical study. The degree of translation movement in comminuted fracture, using titanium IMN system, was 6 times more compared to stainless steel IMN system. Clinical study. The results show that there is a 5.7% of non union and 14% hardware problems with titanium based IMN system when compared to 2.2% non union in the stainless steel IMN system. Titanium based IM nailing system have a potential to inherent mechanical instability when used to treat comminuted fractures. This may explain some of the clinically observed delayed or non-union of femoral fractures

Osteoporosis is a major healthcare burden, responsible for significant morbidity and mortality. Manipulating bone homeostasis would be invaluable in treating osteoporosis and optimising implant osseointegration. Strontium increases bone density through increased osteoblastogenesis, increased bone mineralisation, and reduced osteoclast activity. However, oral treatment may have significant side effects, precluding widespread use. We have recently shown that controlled disorder nanopatterned surfaces can control osteoblast differentiation and bone formation. We aimed to combine the osteogenic synergy of nanopatterning with local strontium delivery to avoid systemic side effects. Using a sol-gel technique we developed strontium doped and/or nanopatterned titanium surfaces, with flat titanium controls including osteogenic and strontium doped media controls. These were characterised using atomic force microscopy and ICP-mass spectroscopy. Cellular response assessed using human osteoblast/osteoclast co-cultures including scanning electron microscopy, quantitative immunofluorescence, histochemical staining, ELISA and PCR techniques. We further performed RNAseq gene pathway combined with metabolomic pathway analysis to build gene/metabolite networks. The surfaces eluted 800ng/cm2 strontium over 35 days with good surface fidelity. Osteoblast differentiation and bone formation increased significantly compared to controls and equivalently to oral treatment, suggesting improved osseointegration. Osteoclast pre-cursor survival and differentiation reduced via increased production of osteoprotegrin. We further delineated the complex cellular signalling and metabolic pathways involved including unique targets involved in osteoporosis. We have developed unique nanopatterned strontium eluting surfaces that significantly increase bone formation and reduce osteoclastogenesis. This synergistic combination of topography and chemistry has great potential merit in fusion surgery and arthroplasty, as well as providing potential targets to treat osteoporosis

Objectives. External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF). Methods. A fracture gap model was created to simulate comminuted mid-shaft tibia fractures using synthetic composite bones. Fifteen constructs were stabilised with ET-LCP, ESS-LCP or UEF (five constructs each). The constructs were loaded under both axial and torsional directions to determine construct stiffness. Results. The mean axial stiffness was very similar for UEF (528 N/mm) and ESS-LCP (525 N/mm), while it was slightly lower for ET-LCP (469 N/mm). One-way analysis of variance (ANOVA) testing in all three groups demonstrated no significant difference (F(2,12) = 2.057, p = 0.171). There was a significant difference in mean torsional stiffness between the UEF (0.512 Nm/degree), the ESS-LCP (0.686 Nm/degree) and the ET-LCP (0.639 Nm/degree), as determined by one-way ANOVA (F(2,12) = 6.204, p = 0.014). A Tukey post hoc test revealed that the torsional stiffness of the ESS-LCP was statistically higher than that of the UEF by 0.174 Nm/degree (p = 0.013). No catastrophic failures were observed. Conclusion. Using the LCP as an external fixator may provide a viable and attractive alternative to the traditional UEF as its lower profile makes it more acceptable to patients, while not compromising on axial and torsional stiffness. Cite this article: B. F. H. Ang, J. Y. Chen, A. K. S. Yew, S. K. Chua, S. M. Chou, S. L. Chia, J. S. B. Koh, T. S. Howe. Externalised locking compression plate as an alternative to the unilateral external fixator: a biomechanical comparative study of axial and torsional stiffness. Bone Joint Res 2017;6:216–223. DOI: 10.1302/2046-3758.64.2000470

Aims

Our objective was to conduct a systematic review and meta-analysis, to establish whether differences arise in clinical outcomes between autologous and synthetic bone grafts in the operative management of tibial plateau fractures.

The concept of stainless steel dual mobility cups in total hip arthroplasty has demonstrated very low long-term instability rates and a 98% survival rate after 12 years. We systematically implanted titanium alloy acetabular cups during a one year period. The purpose of our retrospective study was to report the 18-year clinical outcome data in a homogeneous and continuous series of 103 primary total hip replacements after implantation of a cementless titanium cup. All patients were implanted with NOVAE Ti (SERF) cups made of titanium alloy combined with a retentive polyethylene liner and a 22.2 mm cobalt chrome prosthetic head. Mean patient age at the time of surgery was 53 years. All patients were clinically and radiographically evaluated. The overall 18-year actuarial cup survival rate with a 95% confidence interval was 87.4%. At last follow-up, there was no evidence of implant instability whereas acetabular aseptic loosening was reported in one case and high wear of the retentive liner in 9. The results of this investigation confirmed the long-term stability of dual-mobility implants. The main limitation of this system was early wear of the polyethylene liner in contact with the titanium metal back and reaction with third body along with loss of liner retentivity. In our study, titanium demonstrated favourable osteointegration properties but poor tribologic characteristics, therefore suggesting its interest at the bone-cup interface only

INTRODUCTION. Surgical correction of spinal deformities in the growing child can be applied with or without fusion. Sublaminar wiring, first described by Luque, allows continuation of growth of the non-fused spine after correction of the deformity. Neurological complications and wire breakage are the main clinical problems during the introduction and removal of currently used sublaminar wires. In this pilot study a posterior hybrid construction with the use of a medical-grade UHMWPE (Dyneema Purity®) sublaminar wire was assessed in an ovine model. We hypothesized that such a hybrid construction can safely replace current titanium laminar wires, while providing sufficient stability of the non-fused spinal column with preservation of growth. MATERIALS AND METHODS. This study included 6 Tesselaar sheep, age 7±2months. Two pedicle screws (Legacy system, Medtronic) were placed at lumbar level. Four consecutive laminae were attached to two titanium bars (4.5 mm) using 3 mm diameter UHMWPE (Dyneema Purity®) on the left side and 5 mm diameter on the right side. The sublaminar wires were fixed with a double loop sliding knot and tightened with a tensioning device. As a control, in one animal titanium sublaminar wires (Atlas cable, Medtronic) were applied. After sacrifice the spine of the animals was harvested. Radiographs were taken and CT scans were performed. The vertebrae were dissected and placed in formaldehyde for macroscopic and histological evaluation. RESULTS. The animals were sacrificed after a (minimal) postoperative period of 15 weeks. One animal developed a wire fistula and one animal died the first postoperative day due to complications of the anesthesia. None of the 3 or 5 mm knots loosened and no neurological complications occurred. An average of 8.7 mm growth was seen over the segment operated on. Computed tomography confirmed the preserved stability. Even though no decortication was performed, variable bone bridges with fused levels were seen on CT. Macroscopic and histological analysis showed no inflammation at lamina and dura levels containing Dyneema Purity®, with the exception of the case with the fistula where it was observed locally. DISCUSSION. This pilot animal model study shows that the UHMWPE laminar wire made by Dyneema Purity® has good handling and tensioning properties and can provide sufficient stability in fusionless spinal instrumentation while allowing substantial growth. The examined model showed to be a feasible spinal study model, without occurrence of neurological problems. Reactive periostal bone formation with fusion levels led to some restrictions in this model. In the future it will be necessary to test the described construction in a large animal scoliosis model

Background. The circular Ilizarov frame is a well-established method of external fixation used in the acute treatment of fractures. In our unit, based on our experience, we have changed practice from an all-wire construct to a hybrid, incorporating one 5mm titanium half-pin in the distal reference construct. We were able to compare the all-wire construct against this hybrid in terms of time to union and complications. Methods. All patients who underwent circular frame fixation between 2009 and 2016 for Schatzker IV-VI tibial plateau fractures at one district general hospital were included in the study. The date of union was noted and time to union was calculated. Results. A total of 151 patients were identified for the study. Of these, 17 were excluded due to loss to follow up. In total, 134 patients were included, 74 in the all-wire group and 60 in the hybrid group. Mean time to union was 155.5 days and 114.3 days respectively (p<0.01). Time spent in frame was therefore shorter in the hybrid group. There was no incidence of deep infection in either group and rates of superficial infection were comparable amongst both groups. Previously published data shows there is no difference between the groups in functional scores and SF scores. Conclusions. These results suggest that the hybrid method of Ilizarov fixation is superior to the classical all-wire method. Use of the hybrid construct will reduce time to union, thus improve patient tolerance and reduce associated complications

Introduction. Locking nail have considerably improved the treatment of long weight bearing bones. However, distal locking needs experience and may expose to radiations. Many methods have been proposed to facilitate distal locking and improve safety. Recently, an external distal targeting device adapted to the ancillary of the Long Gamma Nail has been proposed. We report our experience with this device through a comparative series of distal lockings. Aim of this work was to assess feasibility and advantages brought about with this targeting device when considering time or dose of irradiation. Material and methods. Two prospective series of 50 distal locking performed by an experienced surgeon have been compared. Two methods were compared: the classical freehand technique using a Steinmann rod with the image of rounded holes, and the external distal targeting device. The following datas were collected: technical difficulties with either technique, locking mistakes and duration of exposure to radiations. Results. Two locking errors were observed using the targeting device, in pathological fractures with the use of a titanium nail. These cases belonged to the five earliest cases. External targeting device requires a learning curve that is reasonnably short with little difficulties encountered. Ther is a fundamental difference between the two series concerning exposure to radiations. In the freehand technique mean exposure was 25,8s (6–38) and it was 8,6s (6–18) with the dital targeting device. Discussion. A short learning curve confirms the ease of use of the distal targerting device. Diminution of exposure to radiation is effectively obtained. Some factors may increase the risk of error: the use of very long nails and the use of titanium nails as this may increase motion at distal end. Conclusion. The external visor is an efficient device as it facilitates distal locking and alllows for a diminution of irradiation time

In an interdisciplinary project involving electronic engineers and clinicians, a telemetric system was developed to measure the bending load in a titanium internal femoral fixator. As this was a new device, the main question posed was: what clinically relevant information could be drawn from its application? As a first clinical investigation, 27 patients (24 men, three women) with a mean age of 38.4 years (19 to 66) with femoral nonunions were treated using the system. The mean duration of the nonunion was 15.4 months (5 to 69). The elasticity of the plate-callus system was measured telemetrically until union. Conventional radiographs and a CT scan at 12 weeks were performed routinely, and healing was staged according to the CT scans. All nonunions healed at a mean of 21.5 weeks (13 to 37). Well before any radiological signs of healing could be detected, a substantial decrease in elasticity was recorded. The relative elasticity decreased to 50% at a mean of 7.8 weeks (3.5 to 13) and to 10% at a mean of 19.3 weeks (4.5 to 37). At 12 weeks the mean relative elasticity was 28.1% (0% to 56%). The relative elasticity was significantly different between the different healing stages as determined by the CT scans. Incorporating load measuring electronics into implants is a promising option for the assessment of bone healing. Future application might lead to a reduction in the need for exposure to ionising radiation to monitor fracture healing