There is still no consensus on which concentration of mesenchymal stem cells (MSCs) to use for promoting fracture healing in a rat model of long bone fracture. To assess the optimal concentration of MSCs for promoting fracture healing in a rat model. Wistar rats were divided into four groups according to MSC concentrations: Normal saline (C), 2.5 × 106 (L), 5.0 × 106 (M), and 10.0 × 106 (H) groups. The MSCs were injected directly into the fracture site. The rats were sacrificed at 2 and 6 자 post-fracture. New bone formation [bone volume (BV) and percentage BV (PBV)] was evaluated using micro-computed tomography (CT). Histological analysis was performed to evaluate fracture healing score. The protein expression of factors related to MSC migration [stromal cell-derived factor 1 (SDF-1), transforming growth factor-beta 1 (TGF-β1)] and angiogenesis [vascular endothelial growth factor (VEGF)] was evaluated using western blot analysis. The expression of cytokines associated with osteogenesis [bone morphogenetic protein-2 (BMP-2), TGF-β1 and VEGF] was evaluated using real-time polymerase chain reaction. Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture (P = 0.040, P = 0.009; P = 0.004, P = 0.001, respectively). Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture (P = 0.018, P = 0.010; P = 0.032, P = 0.050, respectively). At 2 wk post fracture, SDF-1, TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L (P = 0.031, P = 0.014; P < 0.001, P < 0.001; P = 0.025, P < 0.001, respectively). BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk postfracture (P = 0.037, P = 0.038; P = 0.021, P = 0.010). Compared to group L, TGF-β1 expression was significantly higher in groups H (P = 0.016). There were no significant differences in expression levels of chemokines related to MSC migration, angiogenesis and cytokines associated with osteogenesis between M and H groups at 2 and 6 wk post-fracture. The administration of at least 5.0 × 106 MSCs was optimal to promote fracture healing in a rat model of long bone fractures

This edition of Cochrane Corner looks at some of the work published by the Cochrane Collaboration, covering pharmacological interventions for the prevention of bleeding in people undergoing definitive fixation or joint replacement for hip, pelvic, and long bone fractures; interventions for reducing red blood cell transfusion in adults undergoing hip fracture surgery: an overview of systematic reviews; and pharmacological treatments for low back pain in adults: an overview of Cochrane Reviews

Objectives. Fracture non-union poses a significant challenge to treating orthopaedic surgeons. These patients often require multiple surgical procedures. The incidence of complications after Autologous Bone Graft (ABG) harvesting has been reported up to 44%. These complications include persistent severe donor site pain, infection, heterotopic ossification and antalgic gait. We retrospectively compared the use of BMP-7 alone in long bone fracture Non-union, with patients in whom BMP-7 was used in combination with the Autologous Bone Graft (ABG). Material and Methods. The databases of our dedicated Limb Reconstruction Unit were searched for patient with three common long bone fractures Non-unions (Tibia, Femur and Humerus). The patients who had intra-operative use of Bone Morphogenetic Protein (BMP-7) alone and in combination with ABG were evaluated. 53 Patients had combined use of ABG and BMP-7, and 65 patients had BMP-7 alone. Results. In the ABG and BMP-7 group, the union rate for femoral (n=18) Non-unions was 83%, for humeral (n=16) Non-unions 81%, and for tibia (n=19) Non-unions it was 47%. In the BMP-7 alone group, 83% of the femoral (n=12) Non-unions, 87% of the humeral (n=16) and 56% of the tibial (n=37) Non-unions healed. The common risk factors for Non-union were comparable in both the groups and included location and nature (open vs closed) of fracture, infection, smoking and NSAIDs use. The average time to union in ABG+BMP-7 group was 8.1 months (range 3-30 months) and in BMP-7 alone group it was 7.2 months (range 3-24 months). Conclusion. Autologous Bone Grafting has a pivotal role in limb reconstruction surgery but its indication should be carefully evaluated in view of considerable morbidity associated with graft donor site. Our study did not show any significant difference in the union rates of common long bone fracture Non-unions treated with BMP-7 alone or with a combination of Autologous Bone Graft and BMP-7

Background

Bothlimited-contact dynamic compression plate (LC-DCP) and locking compression plate (LCP) systems were designed to provide enhanced bone healing and to improve stability at fracture site. However, implant failure, delayed union, nonunion and instability are still frequently encountered complications. The purpose of this study was to determine the biomechanical characteristics of a novel persistent compression dynamic plate (PCDP) which provides a persistent compression to fracture edges, and to compare the biomechanical properties of such a novel plate with the commonly used LCP.

Introduction and Objective. Malunion after trauma can lead to coronal plane malalignment in the lower limb. The mechanical hypothesis suggests that this alters the load distribution in the knee joint and that that this increased load may predispose to compartmental arthritis. This is generally accepted in the orthopaedic community and serves as the basis guiding deformity correction after malunion as well as congenital or insidious onset malalignment. Much of the literature surrounding the contribution of lower limb alignment to arthritis comes from cohort studies of incident osteoarthritis. There has been a causation dilemma perpetuated in a number of studies - suggesting malalignment does not contribute to, but is instead a consequence of, compartmental arthritis. In this investigation the relationship between compartmental (medial or lateral) arthritis and coronal plane malalignment (varus or valgus) in patients with post traumatic unilateral limb deformity was examined. This represents a specific niche cohort of patients in which worsened compartmental knee arthritis after extra-articular injury must rationally be attributed to malalignment. Materials and Methods. The picture archiving system was searched to identify all 1160 long leg x ray films available at a major metropolitan trauma center over a 12-year period. Images were screened for inclusion and exclusion criteria, namely patients >10 years after traumatic long bone fracture without contralateral injury or arthroplasty to give 39 cases. Alignment was measured according to established surgical standards on long leg films by 3 independent reviewers, and arthritis scores Osteoarthritis Research Society International (OARSI) and Kellegren-Lawrence (KL) were recorded independently for each compartment of both knees. Malalignment was defined conservatively as mechanical axis deviation outside of 0–20 mm medial from centre of the knee, to give 27 patients. Comparison of mean compartmental arthritis score was performed for patients with varus and valgus malalignment, using Analysis of Variance and linear regression. Results. In knees with varus malalignment there was a greater mean arthritis score in the medial compartment compared to the contralateral knee, with OARSI scores 5.69 vs 3.86 (0.32, 3.35 95% CI; p<0.05) and KL 2.92 vs 1.92 (0.38, 1.62; p<0.005). There was a similar trend in valgus knees for the lateral compartment OARSI 2.98 vs 1.84 (CI −0.16, 2.42; p=0.1) and KL 1.76 vs 1.31 (CI −0.12, 1.01; p=0.17), but the evidence was not conclusive. OARSI arthritis score was significantly associated with absolute MAD (0.7/10mm MAD, p<0.0005) and Time (0.6/decade, p=0.01) in a linear regression model. Conclusions. Malalignment in the coronal plane is correlated with worsened arthritis scores in the medial compartment for varus deformity and may similarly result in worsened lateral compartment arthritis in valgus knees. These findings support the mechanical hypothesis that arthritis may be related to altered stress distribution at the knee, larger studies may provide further conclusive evidence

INTRODUCTION. Intramedullary nail fixation has been used for successful treatment of long bone fracture such as humerus, tibia and femur. We look at the experience of our trauma unit in treating long bone fracture using the AO approved Expert femoral/tibial nail and proximal femoral nail antirotation (PFNA). We look at the union and complication rates in patients treated with AO approved nailing system for pertrochanteric, femoral and tibial shaft fracture. METHODS. We carried out retrospective case notes review of patients that underwent femoral and tibial nailing during the period of study- October 2007 to August 2009. All patients were treated using the AO approved nailing system. We identified all trauma patients that underwent femoral and tibial nailing through the trauma register. Further information was then obtained by going through medical notes and reviewing all followed-up X-rays stored within the online radiology system. RESULTS. 149 patients, 85 male and 64 female were included into the study. 150 procedures were carried out during period of study as 1 patient underwent conversion of lateral entry femoral nail to PFNA due to refracture. Patients' age ranged from 14-96 with mean of 55. 140 patients had isolated long bone fracture (either femur or tibia) compared to 9 patients with multiple bone fractures. Our unit performed 64 Expert tibial nail, 36 PFNA, 31 Expert lateral entry femoral nail and 19 Expert retrograde femoral nail during period of study. 13 patients treated with intramedullary nail sustained open fracture, 9 of them were compound tibial fracture compared to 4 compound femoral fractures. All patients were followed-up between 2 to 24 months or until death. 9 out of 17 patients that died in this study had diagnosis of tumour. Complication rates were 17% for Expert tibial nail (1 patient with valgus deformity, peroneal nerve palsy and delayed union, 3 with delayed union, 4 with broken locking screw, 2 with wound infection and 1 with abscess over wound site), 4% for lateral/retrograde femoral nail (1 each for pulmonary embolism and broken locking screw) and 4% for PFNA (1 each for delayed union and deep vein thrombosis). The overall complication rates were 10% from this study. DISCUSSION & CONCLUSIONS. We conclude that the AO approved nailing system used for treating pertrochanteric, femoral and tibial fractures were effective with high union rate. The overall complication rates were 10% from this study. Complication rates for tibial nail were as high as 17% compared to 4% for femoral nail or PFNA. The complication rates for PFNA in our study were lower compared to 29% in PFN that was reported in one literature

Objectives. To explore the therapeutic potential of combining bone marrow-derived mesenchymal stem cells (BM-MSCs) and hydroxyapatite (HA) granules to treat nonunion of the long bone. Methods. Ten patients with an atrophic nonunion of a long bone fracture were selectively divided into two groups. Five subjects in the treatment group were treated with the combination of 15 million autologous BM-MSCs, 5g/cm. 3. (HA) granules and internal fixation. Control subjects were treated with iliac crest autograft, 5g/cm. 3. HA granules and internal fixation. The outcomes measured were post-operative pain (visual analogue scale), level of functionality (LEFS and DASH), and radiograph assessment. Results. Post-operative pain evaluation showed no significant differences between the two groups. The treatment group demonstrated faster initial radiographic and functional improvements. Statistically significant differences in functional scores were present during the first (p = 0.002), second (p = 0.005) and third (p = 0.01) month. Both groups achieved similar outcomes by the end of one-year follow-up. No immunologic or neoplastic side effects were reported. Conclusions. All cases of nonunion of a long bone presented in this study were successfully treated using autologous BM-MSCs. The combination of autologous BM-MSCs and HA granules is a safe method for treating nonunion. Patients treated with BM-MSCs had faster initial radiographic and functional improvements. By the end of 12 months, both groups had similar outcomes. Cite this article: H.D. Ismail, P. Phedy, E. Kholinne, Y. P. Djaja, Y. Kusnadi, M. Merlina, N. D. Yulisa. Mesenchymal stem cell implantation in atrophic nonunion of the long bones: A translational study. Bone Joint Res 2016;5:287–293. DOI: 10.1302/2046-3758.57.2000587

Long bone fractures in patients with diabetes mellitus (DM) are slow to heal, often resulting in delayed reunion or non-union. It is reasonable to postulate that the underlying cause of these DM-associated complications is a reduced population of bone marrow progenitor cells and/or their dysfunction. With the hypothesis that the administration of healthy, allogeneic adult bone marrow-derived mesenchymal stromal cells (MSCs) can enhance DM fracture healing, the aim of this endeavour was to assess the efficacy of MSC administration to support fracture repair using two doses. Here 250,000 or 500,000 human bone marrow-derived MSCs were locally introduced to femoral fractures in diabetic mice, and the quality of de novo bone assessed 8 weeks later. Preliminary bone bridging was evident in all animals; however, a large circumferential reparative callus was consistently retained indicating non-union. Micro-CT analysis elucidated consistent callus dimensions, bone mineral density, bone volume/total volume in all groups, but an increase in bone surface area/bone volume in cell-treated fractures. Moreover, greater amounts of mature bone were identified in fractures treated with a low dose of MSCs. Four-point bending evaluation of the mechanical integrity of the repairing fracture indicated a statistically significant improvement in flexure strength and flexure modulus in DM fractures treated with 250,000 MSCs as compared to controls. An improvement in total energy required for failure was observed in both groups that received MSCs. Therefore, the administration of non-DM bone marrow-derived MSCs supported the development of more mature bone in the reparative callus, resulting in greater mechanical integrity

Background. The approach to Intramedullary (IM) fixation of long bone fractures remains a controversial issue. Early reports demonstrated less favourable results of retrograde nailing as compared with antegrade options due to higher non-union rates. The aim of this audit was to evaluate the outcomes of practice within the Trauma and Orthopaedic department with relation to IM nail fixation of diaphyseal femur fractures. Methodology. The Trauma database between February 2010 and September 2013 was used to identify all femur IM nailing procedures. Picture Archiving and Communication System (PACS) software was used to classify the fractures according to the Muller AO classification. All 3–2 (Diaphyseal femur fractures) were included in the audit. PACS imaging together with outpatient documentation was evaluated for radiological and clinical outcome. Results. A total sample size of 23 patients was identified (13 antegrade vs. 10 retrograde approach fixations). Mean patient age was 67 years and male to female ratios were similar (11M vs. 12F). Antegrade nailing was performed in a younger population as compared to retrograde nailing (mean age 60 vs. 73 respectively). Mean time to union was somewhat more protracted in the retrograde group (7 vs. 5 months), although all fractures united. The most common complication with relation to antegrade nailing was due to distal locking screws backing out. I case of infection was reported in the retrograde nail group, which was treated successfully with antibiotic therapy. There were 2 cases of nonunion observed in the antegrade group. Conclusions. The results of our practice were comparable to those published in recent literature. Overall, union rates for the two groups of fixation were similar. Each fixation technique is associated with its own specific set of complications. As a general rule antegrade nailing was reserved for a younger population so as to prevent trauma to the native knee joint

Background. Delayed bone healing and nonunion are complications of long bone fractures, with prolonged pain and disability. Regenerative therapies employing mesenchymal stromal cells (MSC) and/or bone substitutes are increasingly applied to enhance bone consolidation. Within the REBORNE project, a multi-center orthopaedic clinical trial was focused on the evaluation of efficacy of expanded autologous bone marrow (BM) derived MSC combined with a CaP-biomaterial to enhance bone healing in patients with nonunion of diaphyseal fractures. To complement the clinical and radiological examination of patients, bone turnover markers (BTM) were assayed as potential predictors of bone healing or non-union. Methods. Bone-specific alkaline phosphatase (BAP), C-terminal-propeptide type I-procollagen (PICP), osteocalcin (OC), β-Cross-Laps Collagen (CTX), soluble receptor activator of NFkB (RANKL), osteoprotegerin (OPG) were measured by ELISA assays in blood samples of 22 patients at BM collection and at follow-ups (6, 12 and 24 weeks post-surgery). Results. A significant relationship with age was found only at Visit 6, with an inverse correlation for CTX, RANKL and OC, and positive for OPG. BTM levels were not related to gender. As an effect of local regenerative process, some BTM showed significant changes in comparison to the starting value. In particular, the time course of BAP, PICP and RANKL was different in patients with a successful healing in comparison to patients with negative outcome. The BTM profile indicated remarkable bone formation activity after 12 weeks after surgery. However, the paucity of failed patients in our case series did not allow to prove statistically the role of BTM as predictors of the final outcome. Conclusion. BTM related to bone cell function are useful to measure the efficacy of a regenerative approach based on expanded MSC. Level of evidence. Diagnostic Level IV. Work supported by the EC, Seventh Framework Programme (FP7), through the REBORNE Project, grant agreement no. 241879

Delayed bone healing and nonunion are complications of long bone fractures, with prolonged pain and disability. Regenerative therapies employing mesenchymal stromal cells (MSC) and/or bone substitutes are increasingly applied to enhance bone consolidation. The REBORNE project entailed a multi-center orthopaedic clinical trial focused on the evaluation of efficacy of expanded autologous bone marrow (BM) derived MSC combined with a CaP-biomaterial, to enhance bone healing in patients with nonunion of diaphyseal fractures. To complement the clinical and radiological examination of patients, bone turnover markers (BTM) were assayed as potential predictors of bone healing or non-union. Peripheral blood was collected from patients at fixed time-endpoints, that is at 6,12 and 24 weeks post-surgery for implantation of expanded autologus MSC and bone-like particles. Bone-specific alkaline phosphatase (BAP), C-terminal-propeptide type I-procollagen (PICP), osteocalcin (OC), β-Cross-Laps Collagen (CTX), soluble receptor activator of NFkB (RANKL), osteoprotegerin (OPG) were measured by ELISA assays in blood samples of 22 patients at BM collection and at follow-up visits. A significant relationship with age was found only at 6 months, with an inverse correlation for CTX, RANKL and OC, and positive for OPG. BTM levels were not related to gender. As an effect of local regenerative process, some BTM showed significant changes in comparison to the baseline value. In particular, the time course of BAP, PICP and RANKL was different in patients with a successful healing in comparison to patients with a negative outcome. The BTM profile apparently indicated a remarkable bone formation activity 12 weeks after surgery. However, the paucity of failed patients in our case series did not allow to prove statistically the role of BTM as predictors of the final outcome. Blood markers related to bone cell function are useful to measure the efficacy of a expanded MSC-regenerative approach applied to long bone non-unions. Changes of the markers may provide a support to radiological assessment of bone healing

This review is aimed at clinicians appraising preclinical trauma studies and researchers investigating compromised bone healing or novel treatments for fractures. It categorises the clinical scenarios of poor healing of fractures and attempts to match them with the appropriate animal models in the literature. We performed an extensive literature search of animal models of long bone fracture repair/nonunion and grouped the resulting studies according to the clinical scenario they were attempting to reflect; we then scrutinised them for their reliability and accuracy in reproducing that clinical scenario. Models for normal fracture repair (primary and secondary), delayed union, nonunion (atrophic and hypertrophic), segmental defects and fractures at risk of impaired healing were identified. Their accuracy in reflecting the clinical scenario ranged greatly and the reliability of reproducing the scenario ranged from 100% to 40%. It is vital to know the limitations and success of each model when considering its application

Long bone fractures are a commonly presented paediatric injury. Whilst the possibility of either accidental or non-accidental aetiology ensures significant forensic relevance, there remain few clinical approaches that assist with this differential diagnosis. The aim of this current study was to generate a reproducible model of spiral fracture in immature bone, allowing investigation of the potential relationship between the rotational speed and the angle of the subsequent spiral fracture. Seventy bovine metacarpal bones were harvested from 7 day old calves. Sharp dissection ensured removal of the soft tissue, whilst preserving the periosteum. The bones were then distributed evenly before eleven groups, before being aligned along their central axis within a torsional testing machine. Each group of bones were then tested to failure at a different rotational speed (0.5, 1, 15, 20, 30, 40, 45, 60, 75, 80 and 90 degrees s-1). The angle of spiral fracture, relative to the long axis, was then measured, whilst the fracture location, the extent of comminution and periosteal disruption, were all recorded. Sixty-two out of 70 specimens failed in spiral fracture, with the remaining tests failing at the anchorage site. All bone fractures centred on the narrowest waist diameter, with 5 specimens (all tested at 90 degrees s-1) demonstrating comminution and periosteal disruption. The recorded spiral fracture angles ranged from 30 - 45 degrees, and were dependant on the rotational speed. This study has established a relationship between the speed of rotation and the angle of spiral fracture in immature bovine bone. It is anticipated that further study will enable investigation of this trend in paediatric bone, ultimately providing an additional diagnostic tool for clinicians trying to verify the proposed mechanism of injury

Tissue reconstruction, based on stem cell activity has become an important part of orthopaedic practice. It is now possible to develop cell lines which are able to produce the fundamental cells which can be used in musculoskeletal regeneration, especially in fracture healing, cartilage regeneration, and muscle repair. However, for the newly implanted cells to be effective, it is vital to have an adequate and developing blood supply to that area. Human and animal studies have demonstrated the marked contribution of bone marrow derived precursor cells in the normal bone healing process. Studies of the application of bone marrow graft have shown that there is greater bone growth when more precursor cells are grafted and these cells are thought to be a mixed population of stems cells and their associated progeny. CD34+ cells have shown remarkable ability to differentiate into many cells types which include chondrocytes and osteocytes. They have also been shown to home on to sites of bone injury and mature into bone cells which take part in the repair process. Colleagues in our laboratories have described a plastic adherent sub-population of CD34+ cells which have been able to reconstitute and sustain hematopoeisis over 5 weeks, similar to long-term marrow culture. This sub-population of cells are called omnicytes. Using this sub-population, we have conducted in vitro and animal experiments using a fracture healing model to assess the role of stem cells in accelerating the fracture healing process. However, it is clear that in order for these cells to be effective, the blood supply needs to be viable. In this paper, the importance of the blood supply and the role of blood flow will be discussed particularly in relation to fracture healing and intervertebral disc regeneration. In fracture healing, the increase of blood flow occurs within the first 6 weeks after the fracture has occurred and CD34+ cells applied to the fracture site via the nutrient artery could accelerate the process of fracture union. In the same way, intervertebral disc patients with chronic low back pain for more than 3 months could be treated with enhanced CD34+ cells in order to allow disc cartilaginous type cells to regenerate. This will be a review of the role of the blood supply, the development of CD34+ cells (namely omnicytes), and the clinical application of these cells to patients with long bone fractures and low back pain

Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant.

Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1–34) 5 μg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters.

These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.