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

Aims. Musculoskeletal infection is a devastating complication in both trauma and elective orthopaedic surgeries that can result in significant morbidity. Aim of this study was to assess the effectiveness and complications of local antibiotic impregnated dissolvable synthetic calcium sulphate beads (Stimulan Rapid Cure) in the hands of different surgeons from multiple centres in surgically managed bone and joint infections. Methods. Between January 2019 and December 2022, 106 patients with bone and joint infections were treated by five surgeons in five hospitals. Surgical debridement and calcium sulphate bead insertion was performed for local elution of antibiotics in high concentration. In all, 100 patients were available for follow-up at regular intervals. Choice of antibiotic was tailor made for each patient in consultation with microbiologist based on the organism grown on culture and the sensitivity. In majority of our cases, we used a combination of vancomycin and culture sensitive heat stable antibiotic after a thorough debridement of the site. Primary wound closure was achieved in 99 patients and a split skin graft closure was done in one patient. Mean follow-up was 20 months (12 to 30). Results. Overall, six out of 106 patients (5.6%) presented with sepsis and poorly controlled comorbid conditions, and died in the hospital within few days of index surgery. Out of the remaining 100 patients, control of infection was achieved in 95 patients (95%). Persistence of infection was noted in five (5%) patients. Out of these 95 patients that had good control of infection, four patients (4.2%) with gap nonunion needed Masquelet procedure to achieve union. Conclusion. Our multicentre experience confirmed that surgical debridement along with calcium sulphate bead insertion was effective in treating bone and joint infections without any side effects and complications. Cite this article: Bone Jt Open 2023;4(7):516–522

Aims. The aim of the present study was to assess the outcomes of the induced membrane technique (IMT) for the management of infected segmental bone defects, and to analyze predictive factors associated with unfavourable outcomes. Methods. Between May 2012 and December 2020, 203 patients with infected segmental bone defects treated with the IMT were enrolled. The digital medical records of these patients were retrospectively analyzed. Factors associated with unfavourable outcomes were identified through logistic regression analysis. Results. Among the 203 enrolled patients, infection recurred in 27 patients (13.3%) after bone grafting. The union rate was 75.9% (154 patients) after second-stage surgery without additional procedures, and final union was achieved in 173 patients (85.2%) after second-stage surgery with or without additional procedures. The mean healing time was 9.3 months (3 to 37). Multivariate logistic regression analysis of 203 patients showed that the number (≥ two) of debridements (first stage) was an independent risk factor for infection recurrence and nonunion. Larger defect sizes were associated with higher odds of nonunion. After excluding 27 patients with infection recurrence, multivariate analysis of the remaining 176 patients suggested that intramedullary nail plus plate internal fixation, smoking, and an allograft-to-autograft ratio exceeding 1:3 adversely affected healing time. Conclusion. The IMT is an effective method to achieve infection eradication and union in the management of infected segmental bone defects. Our study identified several risk factors associated with unfavourable outcomes. Some of these factors are modifiable, and the risk of adverse outcomes can be reduced by adopting targeted interventions or strategies. Surgeons can fully inform patients with non-modifiable risk factors preoperatively, and may even use other methods for bone defect reconstruction. Cite this article: Bone Joint J 2024;106-B(6):613–622

Aims. Fracture-related infections (FRIs) are a devastating complication of fracture management. However, the impact of FRIs on mental health remains understudied. The aim of this study was a longitudinal evaluation of patients’ psychological state, and expectations for recovery comparing patients with recurrent FRI to those with primary FRI. Methods. A prospective longitudinal study was conducted at a level 1 trauma centre from January 2020 to December 2022. In total, 56 patients treated for FRI were enrolled. The ICD-10 symptom rating (ISR) and an expectation questionnaire were assessed at five timepoints: preoperatively, one month postoperatively, and at three, six, and 12 months. Results. Recurrent FRI cases consistently exceeded the symptom burden threshold (0.60) in ISR scores at all assessment points. The difference between preoperative-assessed total ISR scores and the 12-month follow-up was not significant in either group, with 0.04 for primary FRI (p = 0.807) and 0.01 for recurrent FRI (p = 0.768). While primary FRI patients showed decreased depression scores post surgery, recurrent FRI cases experienced an increase, reaching a peak at 12 months (1.92 vs 0.94; p < 0.001). Anxiety scores rose for both groups after surgery, notably higher in recurrent FRI cases (1.39 vs 1.02; p < 0.001). Moreover, patients with primary FRI reported lower expectations of returning to normal health at three (1.99 vs 1.11; p < 0.001) and 12 months (2.01 vs 1.33; p = 0.006). Conclusion. The findings demonstrate the significant psychological burden experienced by individuals undergoing treatment for FRI, which is more severe in recurrent FRI. Understanding the psychological dimensions of recurrent FRIs is crucial for comprehensive patient care, and underscores the importance of integrating psychological support into the treatment paradigm for such cases. Cite this article: Bone Jt Open 2024;5(7):621–627

Aims. Postoperative malalignment of the femur is one of the main complications in distal femur fractures. Few papers have investigated the impact of intraoperative malalignment on postoperative function and bone healing outcomes. The aim of this study was to investigate how intraoperative fracture malalignment affects postoperative bone healing and functional outcomes. Methods. In total, 140 patients were retrospectively identified from data obtained from a database of hospitals participating in a trauma research group. We divided them into two groups according to coronal plane malalignment of more than 5°: 108 had satisfactory fracture alignment (< 5°, group S), and 32 had unsatisfactory alignment (> 5°, group U). Patient characteristics and injury-related factors were recorded. We compared the rates of nonunion, implant failure, and reoperation as healing outcomes and Knee Society Score (KSS) at three, six, and 12 months as functional outcomes. We also performed a sub-analysis to assess the effect of fracture malalignment by plates and nails on postoperative outcomes. Results. The rates of nonunion and reoperation in group U were worse than those in group S (25.0% vs 14.3%; 15.6% vs 5.6%), but the differences were not significant (p = 0.180 and p = 0.126, respectively). Mean KSS in group U at all follow-up periods was significantly worse that in group S (75.7 (SD 18.8) vs 86.0 (SD 8.7); p < 0.001; 78.9 (SD 17.2) vs 89.1 (SD 9.8); p < 0.001; 85.0 (SD 11.9) vs 91.1 (SD 7.2); p = 0.002, respectively). In the sub-analysis of plates, mean KSS was significantly worse in group U at three and six months. In the sub-analysis of nails, the rate of reoperation was significantly higher in group U (28.6% vs 5.8%; p = 0.025), and mean KSS at six and 12 months was significantly worse in Group U. Conclusion. To obtain good postoperative functional results, intraoperative alignment of the coronal plane should be accurately restored to less than 5°. Cite this article: Bone Jt Open 2022;3(2):165–172

Aims. The purpose of this study was to: review the efficacy of the induced membrane technique (IMT), also known as the Masquelet technique; and investigate the relationship between patient factors and technique variations on the outcomes of the IMT. Methods. A systematic search was performed in CINAHL, The Cochrane Library, Embase, Ovid MEDLINE, and PubMed. We included articles from 1 January 1980 to 30 September 2019. Studies with a minimum sample size of five cases, where the IMT was performed primarily in adult patients (≥ 18 years old), in a long bone were included. Multivariate regression models were performed on patient-level data to determine variables associated with nonunion, postoperative infection, and the need for additional procedures. Results. A total of 48 studies were included, with 1,386 cases treated with the IMT. Patients had a mean age of 40.7 years (4 to 88), and the mean defect size was 5.9 cm (0.5 to 26). In total, 82.3% of cases achieved union after the index second stage procedure. The mean time to union was 6.6 months (1.4 to 58.7) after the second stage. Our multivariate analysis of 450 individual patients showed that the odds of developing a nonunion were significantly increased in those with preoperative infection. Patients with tibial defects, and those with larger defects, were at significantly higher odds of developing a postoperative infection. Our analysis also demonstrated a trend towards the inclusion of antibiotics in the cement spacer having a protective effect against the need for additional procedures. Conclusion. The IMT is an effective management strategy for complex segmental bone defects. Standardized reporting of individual patient data or larger prospective trials is required to determine the optimal implementation of this technique. This is the most comprehensive review of the IMT, and the first to compile individual patient data and use regression models to determine predictors of outcomes. Cite this article: Bone Joint J 2020;102-B(12):1723–1734

Aims. To clarify the effectiveness of the induced membrane technique (IMT) using beta-tricalcium phosphate (β-TCP) for reconstruction of segmental bone defects by evaluating clinical and radiological outcomes, and the effect of defect size and operated site on surgical outcomes. Methods. A review of the medical records was conducted of consecutive 35 lower limbs (30 males and five females; median age 46 years (interquartile range (IQR) 40 to 61)) treated with IMT using β-TCP between 2014 and 2018. Lower Extremity Functional Score (LEFS) was examined preoperatively and at final follow-up to clarify patient-centered outcomes. Bone healing was assessed radiologically, and time from the second stage to bone healing was also evaluated. Patients were divided into ≥ 50 mm and < 50 mm defect groups and into femoral reconstruction, tibial reconstruction, and ankle arthrodesis groups. Results. There were ten and 25 defects in the femur and tibia, respectively. Median LEFS improved significantly from 8 (IQR 1.5 to 19.3) preoperatively to 63.5 (IQR 57 to 73.3) at final follow-up (p < 0.001). Bone healing was achieved in all limbs, and median time from the second stage to bone healing was six months (IQR 5 to 10). Median time to bone healing, preoperative LEFS, or postoperative LEFS did not differ significantly between the defect size groups or among the treatment groups. Conclusion. IMT using β-TCP provided satisfactory clinical and radiological outcomes for segmental bone defects in the lower limbs; surgical outcomes were not influenced by bone defect size or operated part. Cite this article: Bone Joint J 2021;103-B(3):456–461

Aims. Bone health assessment and the prescription of medication for secondary fracture prevention have become an integral part of the acute management of patients with hip fracture. However, there is little evidence regarding compliance with prescription guidelines and subsequent adherence to medication in this patient group. Patients and Methods. The World Hip Trauma Evaluation (WHiTE) is a multicentre, prospective cohort of hip fracture patients in NHS hospitals in England and Wales. Patients aged 60 years and older who received operative treatment for a hip fracture were eligible for inclusion in WHiTE. The prescription of bone protection medications was recorded from participants’ discharge summaries, and participant-reported use of bone protection medications was recorded at 120 days following surgery. Results. Of 5456 recruited patients with baseline data, 2853 patients (52%) were prescribed bone protection medication at discharge, of which oral bisphosphonates were the most common, 4109 patients (75%) were prescribed vitamin D or calcium, and 606 patients (11%) were not prescribed anything. Of those prescribed a bone protection medication, only 932 patients (33%) reported still taking their medication 120 days later. Conclusion. These data provide a reference for current prescription and adherence rates. Adherence with oral medication remains poor in patients with hip fracture. Cite this article: Bone Joint J 2019;101-B:1402–1407

This article presents a unified clinical theory that links established facts about the physiology of bone and homeostasis, with those involved in the healing of fractures and the development of nonunion. The key to this theory is the concept that the tissue that forms in and around a fracture should be considered a specific functional entity. This ‘bone-healing unit’ produces a physiological response to its biological and mechanical environment, which leads to the normal healing of bone. This tissue responds to mechanical forces and functions according to Wolff’s law, Perren’s strain theory and Frost’s concept of the “mechanostat”. In response to the local mechanical environment, the bone-healing unit normally changes with time, producing different tissues that can tolerate various levels of strain. The normal result is the formation of bone that bridges the fracture – healing by callus. Nonunion occurs when the bone-healing unit fails either due to mechanical or biological problems or a combination of both. In clinical practice, the majority of nonunions are due to mechanical problems with instability, resulting in too much strain at the fracture site. In most nonunions, there is an intact bone-healing unit. We suggest that this maintains its biological potential to heal, but fails to function due to the mechanical conditions. The theory predicts the healing pattern of multifragmentary fractures and the observed morphological characteristics of different nonunions. It suggests that the majority of nonunions will heal if the correct mechanical environment is produced by surgery, without the need for biological adjuncts such as autologous bone graft. Cite this article: Bone Joint J 2016;98-B:884–91

Objectives. The monitoring of fracture healing is a complex process. Typically, successive radiographs are performed and an emerging calcification of the fracture area is evaluated. The aim of this study was to investigate whether different bone healing patterns can be distinguished using a telemetric instrumented femoral internal plate fixator. Materials and Methods. An electronic telemetric system was developed to assess bone healing mechanically. The system consists of a telemetry module which is applied to an internal locking plate fixator, an external reader device, a sensor for measuring externally applied load and a laptop computer with processing software. By correlation between externally applied load and load measured in the implant, the elasticity of the osteosynthesis is calculated. The elasticity decreases with ongoing consolidation of a fracture or nonunion and is an appropriate parameter for the course of bone healing. At our centre, clinical application has been performed in 56 patients suffering nonunion or fracture of the femur. Results. A total of 39 cases of clinical application were reviewed for this study. In total, four different types of healing curves were observed: fast healing; slow healing; plateau followed by healing; and non-healing. Conclusion. The electronically instrumented internal fixator proved to be valuable for the assessment of bone healing in difficult healing situations. Cost-effective manufacturing is possible because the used electronic components are derived from large-scale production. The incorporation of microelectronics into orthopaedic implants will be an important innovation in future clinical care. Cite this article: B. Kienast, B. Kowald, K. Seide, M. Aljudaibi, M. Faschingbauer, C. Juergens, J. Gille. An electronically instrumented internal fixator for the assessment of bone healing. Bone Joint Res 2016;5:191–197. DOI: 10.1302/2046-3758.55.2000611

The best method of managing a fracture of the distal humerus in a frail low-demand patient with osteoporotic bone remains controversial. Total elbow arthroplasty (TEA) has been recommended for patients in whom open reduction and internal fixation (ORIF) is not possible. Conservative methods of treatment, including the ‘bag of bones’ technique (acceptance of displacement of the bony fragments and early mobilisation), are now rarely considered as they are believed to give a poor functional result. We reviewed 40 elderly and low-demand patients (aged 50 to 93 years, 72% women) with a fracture of the distal humerus who had been treated conservatively at our hospital between March 2008 and December 2013, and assessed their short- and medium-term functional outcome. . In the short-term, the mean Broberg and Morrey score improved from 42 points (poor; 23 to 80) at six weeks after injury to 67 points (fair; 40 to 88) by three months. . In the medium-term, surviving patients (n = 20) had a mean Oxford elbow score of 30 points (7 to 48) at four years and a mean Disabilities of the Arm, Shoulder and Hand score of 38 points (0 to 75): 95% reported a functional range of elbow flexion. The cumulative rate of fracture union at one year was 53%. The mortality at five years approached 40%. . Conservative management of a fracture of the distal humerus in a low-demand patient only gives a modest functional result, but avoids the substantial surgical risks associated with primary ORIF or TEA. Cite this article: Bone Joint J 2015;97-B:1132–8

Objectives. The aim of this systematic literature review was to assess the clinical level of evidence of commercially available demineralised bone matrix (DBM) products for their use in trauma and orthopaedic related surgery. Methods. A total of 17 DBM products were used as search terms in two available databases: Embase and PubMed according to the Preferred Reporting Items for Systematic Reviews and Meta Analyses statement. All articles that reported the clinical use of a DBM-product in trauma and orthopaedic related surgery were included. Results. The literature search resulted in 823 manuscripts of which 64 manuscripts met the final inclusion criteria. The included manuscripts consisted of four randomised controlled trials (level I), eight cohort studies (level III) and 49 case-series (level IV). No clinical studies were found for ten DBM products, and most DBM products were only used in combination with other grafting materials. DBM products were most extensively investigated in spinal surgery, showing limited level I evidence that supports the use Grafton DBM (Osteotech, Eatontown, New Jersey) as a bone graft extender in posterolateral lumbar fusion surgery. DBM products are not thoroughly investigated in trauma surgery, showing mainly level IV evidence that supports the use of Allomatrix (Wright Medical, London, United Kingdom), DBX (DePuy Synthes, Zuchwil, Switzerland), Grafton DBM, or OrthoBlast (Citagenix Laval, Canada) as bone graft extenders. Conclusions. The clinical level of evidence that supports the use of DBM in trauma and orthopaedic surgery is limited and consists mainly of poor quality and retrospective case-series. More prospective, randomised controlled trials are needed to understand the clinical effect and impact of DBM in trauma and orthopaedic surgery. Cite this article: J. van der Stok, K. A. Hartholt, D. A. L. Schoenmakers, J. J. C. Arts. The available evidence on demineralised bone matrix in trauma and orthopaedic surgery: A systemati c review. Bone Joint Res 2017;6:423–432. DOI: 10.1302/2046-3758.67.BJR-2017-0027.R1

Aims. Demineralised bone matrix (DBM) is rarely used for the local delivery of prophylactic antibiotics. Our aim, in this study, was to show that a graft with a bioactive glass and DBM combination, which is currently available for clinical use, can be loaded with tobramycin and release levels of antibiotic greater than the minimum inhibitory concentration for Staphylococcus aureus without interfering with the bone healing properties of the graft, thus protecting the graft and surrounding tissues from infection. Materials and Methods. Antibiotic was loaded into a graft and subsequently evaluated for drug elution kinetics and the inhibition of bacterial growth. A rat femoral condylar plug model was used to determine the effect of the graft, loaded with antibiotic, on bone healing. Results. We found that tobramycin loaded into a graft composed of bioglass and DBM eluted antibiotic above the minimum inhibitory concentration for three days in vitro. It was also found that the antibiotic loaded into the graft produced no adverse effects on the bone healing properties of the DBM at a lower level of antibiotic. Conclusion. This antibiotic-loaded bone void filler may represent a promising option for the delivery of local antibiotics in orthopaedic surgery. Cite this article: Bone Joint J 2016;98-B:1126–31

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

We report the outcome of 84 nonunions involving long bones which were treated with rhBMP-7, in 84 patients (60 men: 24 women) with a mean age 46 years (18 to 81) between 2003 and 2011. The patients had undergone a mean of three previous operations (one to 11) for nonunion which had been present for a mean of 17 months (4 months to 20 years). The nonunions involved the lower limb in 71 patients and the remainder involved the upper limb. A total of 30 nonunions were septic. Treatment was considered successful when the nonunion healed without additional procedures. The relationship between successful union and the time to union was investigated and various factors including age and gender, the nature of the nonunion (location, size, type, chronicity, previous procedures, infection, the condition of the soft tissues) and type of index procedure (revision of fixation, type of graft, amount of rhBMP-7) were analysed. The improvement of the patients’ quality of life was estimated using the Short Form (SF) 12 score. A total of 68 nonunions (80.9%) healed with no need for further procedures at a mean of 5.4 months (3 to 10) post-operatively. Multivariate logistic regression analysis of the factors affecting union suggested that only infection significantly affected the rate of union (p = 0.004).Time to union was only affected by the number of previous failed procedures (p = 0.006). An improvement of 79% and 32.2% in SF-12 physical and mental score, respectively, was noted within the first post-operative year. Rh-BMP-7 combined with bone grafts, enabled healing of the nonunion and improved quality of life in about 80% of patients. Aseptic nonunions were much more likely to unite than septic ones. The number of previous failed operations significantly delayed the time to union. Cite this article: Bone Joint J 2015;97-B:997–1003

Objectives. The biomembrane (induced membrane) formed around polymethylmethacrylate (PMMA) spacers has value in clinical applications for bone defect reconstruction. Few studies have evaluated its cellular, molecular or stem cell features. Our objective was to characterise induced membrane morphology, molecular features and osteogenic stem cell characteristics. Methods. Following Institutional Review Board approval, biomembrane specimens were obtained from 12 patient surgeries for management of segmental bony defects (mean patient age 40.7 years, standard deviation 14.4). Biomembranes from nine tibias and three femurs were processed for morphologic, molecular or stem cell analyses. Gene expression was determined using the Affymetrix GeneChip Operating Software (GCOS). Molecular analyses compared biomembrane gene expression patterns with a mineralising osteoblast culture, and gene expression in specimens with longer spacer duration (> 12 weeks) with specimens with shorter durations. Statistical analyses used the unpaired student t-test (two tailed; p < 0.05 was considered significant). Results. Average PMMA spacer in vivo time was 11.9 weeks (six to 18). Trabecular bone was present in 33.3% of the biomembrane specimens; bone presence did not correlate with spacer duration. Biomembrane morphology showed high vascularity and collagen content and positive staining for the key bone forming regulators, bone morphogenetic protein 2 (BMP2) and runt-related transcription factor 2 (RUNX2). Positive differentiation of cultured biomembrane cells for osteogenesis was found in cells from patients with PMMA present for six to 17 weeks. Stem cell differentiation showed greater variability in pluripotency for osteogenic potential (70.0%) compared with chondrogenic or adipogenic potentials (100% and 90.0%, respectively). Significant upregulation of BMP2 and 6, numerous collagens, and bone gla protein was present in biomembrane compared with the cultured cell line. Biomembranes with longer resident PMMA spacer duration (vs those with shorter residence) showed significant upregulation of bone-related, stem cell, and vascular-related genes. Conclusion. The biomembrane technique is gaining favour in the management of complicated bone defects. Novel data on biological mechanisms provide improved understanding of the biomembrane’s osteogenic potential and molecular properties. Cite this article: Dr H. E. Gruber. Osteogenic, stem cell and molecular characterisation of the human induced membrane from extremity bone defects. Bone Joint Res 2016;5:106–115. DOI: 10.1302/2046-3758.54.2000483

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 objective of this study was to determine if a synthetic bone substitute would provide results similar to bone from osteoporotic femoral heads during in vitro testing with orthopaedic implants. If the synthetic material could produce results similar to those of the osteoporotic bone, it could reduce or eliminate the need for testing of implants on bone. Methods. Pushout studies were performed with the dynamic hip screw (DHS) and the DHS Blade in both cadaveric femoral heads and artificial bone substitutes in the form of polyurethane foam blocks of different density. The pushout studies were performed as a means of comparing the force displacement curves produced by each implant within each material. Results. The results demonstrated that test material with a density of 0.16 g/cm. 3. (block A) produced qualitatively similar force displacement curves for the DHS and qualitatively and quantitatively similar force displacement curves for the DHS Blade, whereas the test material with a density of 0.08 g/cm. 3. (block B) did not produce results that were predictive of those recorded within the osteoporotic cadaveric femoral heads. Conclusion. This study demonstrates that synthetic material with a density of 0.16 g/cm. 3. can provide a good substitute for cadaveric osteoporotic femoral heads in the testing of implants. However we do recognise that no synthetic material can be considered as a definitive substitute for bone, therefore studies performed with artificial bone substrates may need to be validated by further testing with a small bone sample in order to produce conclusive results

Low-energy fractures of the proximal humerus indicate osteoporosis and it is important to direct treatment to this group of patients who are at high risk of further fracture. Data were prospectively collected from 79 patients (11 men, 68 women) with a mean age of 69 years (55 to 86) with fractures of the proximal humerus in order to determine if current guidelines on the measurement of the bone mineral density at the hip and lumbar spine were adequate to stratify the risk and to guide the treatment of osteoporosis. Bone mineral density measurements were made by dual-energy x-ray absorptiometry at the proximal femur, lumbar spine (L2-4) and contralateral distal radius, and the T-scores were generated for comparison. Data were also collected on the use of steroids, smoking, the use of alcohol, hand dominance and comorbidity. The mean T-score for the distal radius was −2.97 (. sd. 1.56) compared with −1.61 (. sd. 1.62) for the lumbar spine and −1.78 (. sd. 1.33) for the femur. There was a significant difference between the mean lumbar and radial T scores (1.36 (1.03 to 1.68); p < 0.001) and between the mean femoral and radial T-scores (1.18 (0.92 to 1.44); p < 0.001). The inclusion of all three sites in the determination of the T-score increased the sensitivity to 66% compared with that of 46% when only the proximal femur and lumbar spine were used. This difference between measurements in the upper limb compared with the axial skeleton and lower limb suggests that basing risk assessment and treatment on only the bone mineral density taken at the hip or lumbar spine may misrepresent the extent of osteoporosis in the upper limb and the subsequent risk of fracture at this site. The assessment of osteoporosis must include measurement of the bone mineral density at the distal radius to avoid underestimation of osteoporosis in the upper limb

Objectives. Because of the contradictory body of evidence related to the potential benefits of helical blades in trochanteric fracture fixation, we studied the effect of bone compaction resulting from the insertion of a proximal femoral nail anti-rotation (PFNA). . Methods. We developed a subject-specific computational model of a trochanteric fracture (31-A2 in the AO classification) with lack of medial support and varied the bone density to account for variability in bone properties among hip fracture patients. Results. We show that for a bone density corresponding to 100% of the bone density of the cadaveric femur, there does not seem to be any advantage in using a PFNA with respect to the risk of blade cut-out. On the other hand, in a more osteoporotic femoral head characterised by a density corresponding to 75% of the initial bone density, local bone compaction around the helical blade provides additional bone purchase, thereby decreasing the risk of cut-out, as quantified by the volume of bone susceptible to yielding. Conclusions. Our findings indicate benefits of using a PFNA over an intramedullary nail with a conventional lag screw and suggest that any clinical trial reporting surgical outcomes regarding the use of helical blades should include a measure of the femoral head bone density as a covariable