The Cierny and Mader classification assists with decision-making in the management of osteomyelitis by strafying the host status and the pathoanatomy of disease. However the anatomical type IV represents a heterogenous group with regards to treatment requirements and outcomes. We propose that modification of the Cierny and Mader anatomical classification with an additional type V classifier (diffuse corticomedullary involvement with an associated critical bone defect) will allow more accurate stratification of patients and tailoring of treatment strategies. A retrospective review of 83 patients undergoing treatment for Cierny and Mader anatomical type IV osteomyelitis of the appendicular skeleton at a single centre was performed. Risk factors for the presence of a critical bone defect were female patients (OR 3.1 (95% CI 1.08– 8.92)) and requirement for soft tissue reconstruction (OR 3.35 (95% CI 1.35–8.31)); osteomyelitis of the femur was negatively associated with the presence of a critical bone defect (OR 0.13 (95% CI 0.03–0.66)). There was no statistical significant risk of adverse outcomes (failure to eradicate infection or achieve bone union) associated with the presence of a critical-sized bone defect. The median time to bone union was ten months (95% CI 7.9–12.1 months). There was a statistically significant difference in the median time to bone union between cases with a critical bone defect (12.0 months (95% 10.2–13.7 months)) and those without (6.0 months (95% CI 4.8–7.1 months)). This study provided evidence to support the introduction of a new subgroup of the Cierny and Mader anatomical classification (Type V). Using a standardised approach to management, comparable early outcomes can be achieved in patients with Cierny and Mader anatomical type V osteomyelitis. However, to achieve a successful outcome, there is a requirement for additional bone and soft tissue reconstruction procedures with an associated increase in treatment time

Introduction. The Cierny and Mader classification assists with decision-making by stratifying host status and the pathoanatomy of the disease. However, the anatomical type IV represents a heterogenous group with regards to treatment requirements and outcomes. We propose that modification of the Cierny and Mader anatomical classification with an additional type V classifier (diffuse corticomedullary involvement with an associated critical bone defect) will allow more accurate stratification of patients and tailoring of treatment strategies. Materials & Methods. A retrospective review of 83 patients undergoing treatment for Cierny and Mader anatomical type IV osteomyelitis of the appendicular skeleton at a single centre was performed. Results. Risk factors for the presence of a critical bone defect were female patients (OR 3.1 (95% CI 1.08–8.92)) and requirement for soft tissue reconstruction (OR 3.35 (95% CI 1.35–8.31)); osteomyelitis of the femur was negatively associated with the presence of a critical bone defect (OR 0.13 (95% CI 0.03–0.66)). There was no statistically significant risk of adverse outcomes (failure to eradicate infection or achieve bone union) associated with the presence of a critical-sized bone defect. The median time to bone union was ten months (95% CI 7.9–12.1 months). There was a statistically significant difference in the median time to bone union between cases with a critical bone defect (12.0 months (95% 10.2–13.7 months)) and those without (6.0 months (95% CI 4.8–7.1 months)). Conclusions. This study provided evidence to support the introduction of a new subgroup of the Cierny and Mader anatomical classification (Type V). Using a standardised approach to management, comparable early outcomes can be achieved in patients with Cierny and Mader anatomical type V osteomyelitis. However, to achieve a successful outcome, there is a requirement for additional bone and soft tissue reconstruction procedures with an associated increase in treatment time

Aim. The primary endpoint of this study is to characterize the progression of bone defects at the femoral and tibial side in patients who sustained PJI of the knee that underwent two-stage revision with spacer implantation. In addition, we want to analyze the differences between functional moulded and hand-made spacers. Methods. A retrospective analysis of patients that underwent two-stage revision due to PJI of the knee between January 2014 and December 2021 at our institution. Diagnosis of infection was based on the criteria of the Muscoloskeletal Infection Society. The bone defect evaluation was performed intraoperatively based on the AORI classification. The basal evaluation was performed at the time the resection arthroplasty and spacer implantation surgery. The final evaluation was performed at the second-stage surgery, at the time of spacer removal and revision implant positioning. The differences between groups were characterized by using T-test student for continuous variables, and by using chi-square for categorical variables. A p-value < 0.05 was defined as significant. Results. Complete data of 37 two-stage TKAs revision were included in the study. An articulating moulded functional spacer was used in 14 (35.9%) cases, while a hand-made spacer was used in 23 (58.9%) cases. The average length of interval period (excluding the time for patients that retained the spacer) was 146.6 days. A bone defects progression based on the AORI classification was documented in 24 cases at the femoral side (61.6%), a bone defect progression was documented in 17 cases at the tibial side (43.6%), and a bone defect at both sides was documented in 13 cases (33.3%). A statistically significant greater bone defect progression at the tibial side was observed when hand-made spacers were used. A complication during the interval period was reported in five cases (12.8%) and postoperative complication was reported in 9 cases (23.1%). Conclusions. When comparing patients in which a functional articulating spacer was used, with patients in which static spacer was used, we reported a statistically significant reduced bone defect progression during the interval period at the femoral side only when moulded spacers were used. We observed a higher incidence of bone defect progression also at the tibial and both sides when hand-made spacers were used. This is the first study that documented the bone defect progression during two-stage revision of the knee, the results observed in this study are very encouraging

Introduction. A significant burden of disease exists with respect to critical sized bone defects; outcomes are unpredictable and often poor. There is no absolute agreement on what constitutes a “critically-sized” bone defect however it is widely considered as one that would not heal spontaneously despite surgical stabilisation, thus requiring re-operation. The aetiology of such defects is varied. High-energy trauma with soft tissue loss and periosteal stripping, bone infection and tumour resection all require extensive debridement and the critical-sized defects generated require careful consideration and strategic management. Current management practice of these defects lacks consensus. Existing literature tells us that tibial defects 25mm or great have a poor natural history; however, there is no universally agreed management strategy and there remains a significant evidence gap. Drawing its origins from musculoskeletal oncology, the Capanna technique describes a hybrid mode of reconstruction. Mass allograft is combined with a vascularised fibula autograft, allowing the patient to benefit from the favourable characteristics of two popular reconstruction techniques. Allograft confers initial mechanical stability with autograft contributing osteogenic, inductive and conductive capacity to encourage union. Secondarily its inherent vascularity affords the construct the ability to withstand deleterious effects of stressors such as infection that may threaten union. The strengths of this hybrid construct we believe can be used within the context of critical-sized bone defects within tibial trauma to the same success as seen within tumour reconstruction. Methodology. Utilising the Capanna technique in trauma requires modification to the original procedure. In tumour surgery pre-operative cross-sectional imaging is a pre-requisite. This allows surgeons to assess margins, plan resections and order allograft to match the defect. In trauma this is not possible. We therefore propose a two-stage approach to address critical-sized tibial defects in open fractures. After initial debridement, external fixation and soft tissue management via a combined orthoplastics approach, CT imaging is performed to assess the defect geometry, with a polymethylmethacrylate (PMMA) spacer placed at index procedure to maintain soft tissue tension, alignment and deliver local antibiotics. Once comfortable that no further debridement is required and the risk of infection is appropriate then 3D printing technology can be used to mill custom jigs. Appropriate tibial allograft is ordered based on CT measurements. A pedicled fibula graft is raised through a lateral approach. The peroneal vessels are mobilised to the tibioperoneal trunk and passed medially into the bone void. The cadaveric bone is prepared using the custom jig on the back table and posterolateral troughs made to allow insertion of the fibula, permitting some hypertrophic expansion. A separate medial incision allows attachment of the custom jig to host tibia allowing for reciprocal cuts to match the allograft. The fibula is implanted into the allograft, ensuring nil tension on the pedicle and, after docking the graft, the hybrid construct is secured with multi-planar locking plates to provide rotational stability. The medial window allows plate placement safely away from the vascular pedicle. Results. We present a 50-year-old healthy male with a Gustilo & Anderson 3B proximal tibial fracture, open posteromedially with associated shear fragment, treated using the Capanna technique. Presenting following a fall climbing additional injuries included a closed ipsilateral calcaneal and medial malleolar fracture, both treated operatively. Our patient underwent reconstruction of his tibia with the above staged technique. Two debridements were carried out due to a 48-hour delay in presentation due to remote geographical location of recovery. Debridements were carried out in accordance with BOAST guidelines; a spanning knee external fixator applied and a small area of skin loss on the proximal medial calf reconstructed with a split thickness skin graft. A revision cement spacer was inserted into the metaphyseal defect measuring 84mm. At definitive surgery the external fixator was removed and graft fixation was extended to include the intra-articular fragments. No intra-operative complications were encountered during surgeries. The patient returned to theatre on day 13 with a medial sided haematoma. 20ml of haemoserous fluid was evacuated, a DAIR procedure performed and antibiotic-loaded bioceramics applied locally. Samples grew Staphylococcus aureus and antibiotic treatment was rationalised to Co-Trimoxazole 960mg BD and Rifampicin 450mg BD. The patient has completed a six-week course of Rifampicin and continues on suppressive Co-Trimoxazole monotherapy until planned metalwork removal. There is no evidence of ongoing active infection and radiological evidence of early union. The patient is independently walking four miles to the gym daily and we believe, thus far, despite accepted complications, we have demonstrated a relative early success. Conclusions. A variety of techniques exist for the management of critical-sized bone defects within the tibia. All of these come with a variety of drawbacks and limitations. Whilst acceptance of a limb length discrepancy is one option, intercalary defects of greater than 5 to 7cm typically require reconstruction. In patients in whom fine wire fixators and distraction osteogenesis are deemed inappropriate, or are unwilling to tolerate the frequent re-operations and potential donor site morbidity of the Masqualet technique, the Capanna technique offers a novel solution. Through using tibial allograft to address the size mismatch between vascularised fibula and tibia, the possible complication of fatigue fracture of an isolated fibula autograft is potentially avoidable in patients who have high functional demands. The Capanna technique has demonstrated satisfactory results within tumour reconstruction. Papers report that by combining the structural strength of allograft with the osteoconductive and osteoinductive properties of a vascularised autograft that limb salvage rates of greater than 80% and union rates of greater than 90% are achievable. If these results can indeed be replicated in the management of critical-sized bone defects in tibial trauma we potentially have a treatment strategy that can excel over the more widely practiced current techniques

Introduction. Acetabular bone defects are still challenging to quantify. Numerous classification schemes have been proposed to categorize the diverse kinds of defects. However, these classification schemes are mainly descriptive and hence it remains difficult to apply them in pre-clinical testing, implant development and pre-operative planning. By reconstructing the native situation of a defect pelvis using a Statistical Shape Model (SSM), a more quantitative analysis of the bone defects could be performed. The aim of this study is to develop such a SSM and to validate its accuracy using relevant clinical scenarios and parameters. Methods. An SSM was built on the basis of segmented 66 CT dataset of the pelvis showing no orthopedic pathology. By adjusting the SSM's so called modes of shape variation it is possible to synthetize new 3D pelvis shapes. By fitting the SSM to intact normal parts of an anatomical structure, missing or pathological regions can be extrapolated plausibly. The validity of the SSM was tested by a Leave-one-out study, whereby one pelvis at a time was removed from the 66 pelvises and was reconstructed using a SSM of the remaining 65 pelvises. The reconstruction accuracy was assessed by comparing each original pelvis with its reconstruction based on the root-mean-square (RMS) surface error and five clinical parameters (center of rotation, acetabulum diameter, inclination, anteversion, and volume). The influence of six different numbers of shape variation modes (reflecting the degrees of freedom of the SSM) and four different mask sizes (reflecting different clinical scenarios) was analyzed. Results. The Leave-one-out study showed that the reconstruction errors decreased when the number of shape variation modes included in the SSM increased from 0 to 20, but remained almost constant for higher numbers of shape variation modes. For the SSM with 20 shape variation modes, the RMS of the reconstruction error increased with increasing mask size, whereas the other parameters only increased from Mask_0 to Mask_1, but remained almost constant for Mask_1, Mask_2 and Mask_3. Median reconstruction errors for Mask_1, Mask_2, and Mask_3 were approximately 3 mm in Center of Rotation (CoR) position, 2 mm in Diameter, 3° in inclination and anteversion, as well as 5 ml in volume. Discussion. This is the first study analyzing and showing the feasibility of a quantitative analysis of acetabular bone defects using a SSM-based reconstruction method in the clinical scenario of a defect or implant in both acetabuli and incomplete CT-scans. Validation results showed acceptable reconstruction accuracy, also for clinical scenarios in which less healthy bone remains. Further studies could apply this method on a larger number of defect pelvises to obtain quantitative measures of acetabular bone defects

Purpose. The aim of this study was to compare the clinical outcomes of the revision TKA in which trabecular metal cones and femoral head allografts were used for large bone defect. Method. Total 53 patients who have undergone revision TKA from July 2013 to March 2017 were enrolled in this study. Among them, 24 patients used trabecular metal cones, and 29 patients used femoral head allografts for large bone defect. There were 3 males and 21 females in the metal cone group, while there were 4 males and 25 females in the allograft group. The mean age was 70.2 years (range, 51–80) in the femoral head allograft group, while it was 79.1 years (range, 73–85) in the metal cone group. Bone defect is classified according to the AORI classification and clinical outcomes were evaluated with Visual Analogue Scale (VAS), Hospital Special Surgery-score (HSS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS), and ROM. Operation time was also evaluated. We used radiographs to check complications such as migration or loosening. We took follow-up x-rays and 3D CT of the patients, to assess the mean bone union period. Shapiro-Wilk test was done to check normality and Student T-test and Mann Whitney U-test were done for comparison between two groups. Result. The mean follow-up period was 3 .75 years (Range; 2.1 ∼ 5.75). The pre-op scores did not show significant difference. The mean VAS in the allograft and trabecular metal cone groups was 2.1 ± 0.87 and 1.8 ± 0.53, respectively (p = 0.16). The mean HSS score were 76.3 ± 5.51 and 79.2 ± 4.12 respectively (p = 0.13) and the mean WOMAC scores were 15.1 ± 3.25 and 14.8 ± 3.31 respectively (p = 0.06), and the mean KOOS scores were 27.8 ± 4.77 and 25.5 ± 4.84, respectively (p = 0.07). The mean ROM ranges were 100.6 ± 17.54 and 101.3 ± 19.22, respectively (p = 0.09). But the mean operation time of the allograft and trabecular metal cone groups was 137 minutes (Range; 111–198) and 102minutes (Range; 93 −133) (p=0.02) respectively, which showed statistical significance. In follow-up x-rays, no migration or loosening of the implants, osteolysis and other complications were found in both groups. In follow-up 3D CT, osteointegration was seen at the trabecular metal cone site, host bone being interpreted to the host bone. The allograft group showed fibrous and stable union in follow-up 3D CT. Conclusion. According to this study, in case of revision TKA with large bone defect, using whether allograft or trabecular metal cones did not affect the clinical outcomes. However, operation time was significantly shorter in trabecular metal cone group, therefore, in patients with poor general condition along with severe underlying diseases, usage of trabecular metal cone would be a better choice to shorten operation time and ease postoperative care. Keywords. Revision TKA, metal cone, allograft, bone defect. For any figures or tables, please contact authors directly

Purpose. The aim of this study was to assess the clinical and radiological result of the usage of chip bone graft in non-contained type bone defect in primary or revision total knee arthroplasty patients. Subjects and Methods. We investigated 32 patients who had underwent primary or revision total knee arthroplasty from March, 2014 to February, 2017 in our hospital, who had non-contained type of defect. The mean age was 73.1 years. 5 of them were males, while 27 of them were females. 7 of them were primary total knee arthroplasty patients, while 25 of them were revision patients. 8 of them had chip bone graft used both in the femur and tibia. 9 of them had chip bone graft used only in the tibia. The other 15 had chip bone graft used only in the femur. Wire-mesh was used in the 9 patients who had chip bone graft used only in the medial side of the tibia. We used KOOS (Knee injury and osteoarthritis outcome score), HSS (Hospital for Special Surgery knee service rating system) and WOMAC scores to assess the clinical result, before the surgery and at the last follow-up. In addition, we had follow-up x-rays and 3D CT done for the patients to check the mean bone union period. In addition, overall radiologic imaging studies were used for complications such as loosening, osteolysis and lesions with radiolucency. Result. The Mean follow-up period was 2.7 years (range; 2.1 to 5). The Mean preoperative KOOS was 102.8 (range; 47 to 132), while it became 31.8 postoperatively (range; 20 to 45). The mean HSS was 13.1 (range; 6 to 35), while it became 35.9 postoperatively (range; 24 to 64). The mean WOMAC was 82.9 (range; 62 to 92), while it became 22.5 postoperatively (range; 13 to 30). According to follow-up x-ray and CT, the mean bone union period was 10.6 months (range: 10 to 13). In follow-up 3D CT of all cases, we could check cortical healing and new bone formation, seen as medium to high-attenuating conglomerate. The graft-host junction showed trabecular ingrowth, while the medullary canal showed fibrous ingrowth. Radiologically, there was no complication such as loosening, osteolysis, migration and radiolucent lines around the stems or cement mantles. In addition, there was no complication such as infection. Conclusion. Chip bone graft is not a commonly used method for bone defect in total knee arthroplasty. According to the result of the usage of chip bone graft in primary or revision total knee arthroplasty with non-contained type of bone defect, it showed favorable result for the subject patients. Therefore, we can consider it as one of the effective methods to manage non-contained bone defect in knee arthroplasty. Keywords. Revision TKA, chip bone graft, wire-mesh, non-contained bone defect. For any figures or tables, please contact authors directly

Treatment of segmental bone defects remains a major clinical problem, and innovative strategies are often necessary to successfully reconstruct large volumes of bone. When fractures occur, the resulting hematoma serves as a reservoir for growth factors and a space for cell infiltration, both crucial to the initiation of bone healing. Our previous studies have demonstrated very clear ultrastructural differences between fracture hematomas formed in normally healing fractures and those formed in segmental bone defects. However, there is little information available regarding potential differences in the underlying gene expression between hematomas formed in normal fractures, which usually heal by themselves, and segmental bone defects, which do not. Therefore, the aim of this study was to identify differences in gene expression within hematomas collected from 0.5 mm (normal fracture) and 5 mm (segmental bone defect) fracture sites during the earliest stages of bone healing. Osteotomies of 0.5 and 5 mm in the femur of Fisher 344 rats were stabilized with external fixators (RISystem AG). After 3 days the rats were sacrificed, and the fracture hematomas were collected for RNA-sequencing. Ingenuity pathway analysis (IPA) was used to identify upstream regulators and biological functions that were significantly enriched with differentially expressed genes from the RNA-sequencing analysis. Animal procedures were conducted following the IACUC protocol of the UT Health Science Center San Antonio. Key upstream regulators of bone formation were less active (e.g. TGFB1, FGF2, SMAD3) or even inhibited (e.g. WNT3A, RUNX2, BMP2) in non-healing defects when compared to normally healing fractures. Many upstream regulators that were uniquely enriched in healing defects were molecules recently discovered to have osteogenic effects during fracture healing (e.g. GLI1, EZH2). Upstream regulators uniquely enriched in non-healing defects were mainly involved in an abnormal modulation of hematopoiesis, revealing evidence of impaired maturation of functional macrophages and cytokines (e.g. IL3, CEBPE), both essential for successful bone healing. In addition, the enrichment pattern suggested a dysregulation of megakaryopoiesis (e.g. MRTFA, MRTFB, GATA2), which directly affects platelet production, and therefore fracture hematoma formation. Remarkably, the organization of the ECM was the most significantly enriched biological function in the normally healing fractures, and implies that the defect size directly affected the structural properties within the fracture hematoma. Conversely, genes encoding important ECM components (e.g. BGN, various collagens, IBSP, TNC), cell adhesion molecules, MMPs (MMP2), and TIMPs were all significantly downregulated in non-healing defects. Our most recent findings reveal new important key molecules that regulate defect size-dependent fracture healing. Combined with our previous results, which identified structural differences in fracture hematomas from both types of defects, current findings indicate that differential expression of genes is dictated by the structural properties of the hematomas formed during early fracture healing. Consequently, creating a bioscaffold that mimics the structure of normal fracture hematomas could be the first step towards developing new orthoregenerative treatment strategies that potentiate healing of large bone defects and non-healing fractures

Acetabular reconstruction of extensive bone defect is troublesome in revision total hip arthroplasty (rTHA). Kerboull or Kerboull type reinforcement acetabular device with allobone grafting has been applied since 1996. Clinical results of the procedure were evaluated. Patients. One hundred and ninety-two consecutive revision total hip arthroplasties were performed with allograft bone supported by the Kerboull or Kerboull type reinforcement acetabular device from 1996 to 2009. There were 23 men and 169 women. Kerboull plates were applied to 18 patients, and Kerboull type plates to 174. The mean follow up of the whole series was 8 years (4–18years). Surgical Technique. The superior bone defect was reconstructed principally by a large bulky allo block with plate system. Medial bone defect was reconstructed by adequate bone chips and/or sliced bone plates. After temporally fixation of bulky bone block with two 2.0mm K-wires, it was remodeled by reaming to fit the gap between host bone and plate, followed by fixation to the iliac bone by screws. Finally, residual space of the defect between host bone and the fixed plated was filled up with morselized cancellous bones, bone chips, and/or wedged bony fragments with impaction. This method was sufficiently applicable to AAOS Typeâ�, II, and III bone defects. In case of AAOS Typeâ�£, the procedure was also available after repairing discontinuation between distal and proximal bones by reconstrusion plate or allografting with tibial bone plates or sliced femoral head. Results. Nine patients (4.7%) required revision surgery (infection 5, breakage 3, and malalignment 1). The plate breakage was observed in 8 joints (4.2%). Three patients had no symptoms after the breakage. Three required revision, but the other cases were carefully observed without additional surgical intervention. Ten-year survival rate by Kaplan-Meier method was 96.6% when the endpoint was set revision by asceptic loosning. Conclusions. This study indicated that acetabular allograft reconstructions reinforced by Kerboull or Kerboull type acetabular device were able to recover bone stock with anatomic reconstruction of femoral head center, thus providing satisfactory clinical results in middle term period

This article is based on the analysis of surgical treatment peculiarities of 641 patients with post-osteomyelitis long bones defects. The average age of patients at the time of hospital admission was 32,4 ± 0,7 and ranged from 4 to 70 years. Most of them were people of active working age (476 (74.3%)) and male (523 (81.1%)). In this observation group 566 (88.3%) patients had the osteomyelitis process of the traumatic origin, including post-surgical (n = 155) and post-gunshot injuries (n = 13). Chronic hematogenous osteomyelitis was diagnosed in 75 (11.7%) patients. Most patients had lower extremity bones problems, including 444 tibia defects and 142 femoral bone defects. Much fewer patients had the osteomyelitis process of the upper extremity (humerus, radius, ulnar bone – 18, 19 and 18 respectively). Purulent necrotic process was accompanied by nonunion bone fragments in 160 (24%) patients, delayed union in 95 (14.6%) patients, false joint in 178 (27.6%) patients, segmental bone defect in 75 (11 5%) patients and bones union with edge defects and cavities in 143 (22.3%) patients. 340 (53%) patients were operated using the method of free bone grafting, and 301 (47%) patients were operated using the distraction method. The need to use the bilocal for external fixation on upper extremities occurs quite seldom (twice in our observations). Even when there is an upper extremity bone defect of several centimeters the preference should be given not to bilocal external fixation. When treating the lower extremities taking the above mentioned into consideration, segmental defects predominated, that is why the bilocal distraction-compression method of surgical treatment prevailed (98.6%). Thus, the main method of upper extremities long bones defects replacement is free bone grafting with segment fixation by the external fixation device, for lower extremities the is not-free main Ilizarov method, which allows to get positive results in 84.6% of patients with femoral bone problems and in 96.4% of tibia problems, mainly due to one-step treatment, directed simultaneously to inflammatory process elimination and maximum possible anatomical and functional restoration of the affected extremity

Introduction. The bone defect reconstruction is the first step of successful primary or revision TKA in case of large bone defect. If the defect is not reconstructed adequately, we can neither preserve knee joint function nor guarantee long survival of the implant. Allogeneic bone graft is known to be the treatment of choice in large defect. However the surgical technique is demanding and incorporation failure is constant issue of the allogeneic bone graft. We propose new bone defect reconstruction technique using multiple screws and cement. Material and method. From April 2012 to April 2014, 12 patients with large defect which could not be reconstructed with metal augment were involved in this study. The bone defect type was 10 cases of 2A and 2 cases of 2B according to AORI (Anderson Orthopedic Research Institute) classification. The defect was reconstructed with multiple screws and cementing technique by single surgeon (WS Cho). Average follow-up period was 15 months. (24 ∼ 1 month). Result. We analyzed 6 patients whose follow-up periods were more than 12 months. Average ROM was 107' and clinical scores were 86 by HSS, 93 by KS and 11 by WOMAC respectively. No complications such as infection and loosening were developed. Mean surgical time was 1 hour and 57 minutes. Conclusion. In short term follow-up, cementing technique using multiple screws can be a solution for large bone defect reconstruction

Purpose. Angiogenesis and osteogenesis are essential for bone growth, fracture repair, and bone remodeling. VEGF has an important role in bone repair by promoting angiogenesis and osteogenesis. In our previous study, endothelial progenitor cells (EPCs) promoted bone healing in a rat segmental bone defect as confirmed by radiological, histological and microCT evaluations (Atesok, Li, Schemitsch 2010); EPC treatment of fractures resulted in a significantly higher strength by biomechanical examination (Li, Schemitsch 2010). In addition, cell-based VEGF gene transfer has been effective in the treatment of segmental bone defects in a rabbit model (Li, Schemitsch et al 2009); Purpose of this study: Evaluation of VEGF gene expression after EPC local therapy for a rat segmental bone defect. Method. Rat bone marrow-derived EPCs were isolated from the rat bone marrow by the Ficoll-paque gradient centrifuge technique. The EPCs were cultured for 7 to 10 days in endothelial cell growth medium with supplements (EGM-2-MV-SingleQuots, Clonetics). and collected for treatment of the rat segmental bone defect. EPCs were identified by immunocytochemistry staining with primary antibodies for CD34, CD133, FLK-1, and vWF. A total of fifty six rats were studied. A five millimeter segmental bone defect was created in the middle 1/3 of each femur followed by mini plate fixation. The treatment group received 1×106 EPCs locally at the bone defect and control animals received saline only. Seven control and seven EPC treated rats were included in each group at 1, 2, 3 and 10 weeks. Animals were sacrificed at the end of the treatment period, and specimens from the fracture gap area were collected and immediately frozen. Rat VEGF mRNA was measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and quantified by VisionWorksLS. All measurements were performed in triplicate. Results. Cultured EPCs at 1 week showed positive staining for CD34, CD133, Flk-1 and vWf markers. The EPC group had a greater VEGF expression than the control group at week 1, 2 and 3 but not at week 10. Three VEGF isoforms were detected in this rat model: VEGF120, VEGF164 and VEGF188. VEGF120 and VEGF164 levels peaked at two weeks, while VEGF188 levels peaked at three weeks. All three VEGF isoform levels were low at ten weeks. Conclusion. EPC-based therapy for a segmental bone defect results in increased VEGF expression during the early period of fracture repair. In addition, the specific VEGF isoform may be a key regulator of the bone healing process. These findings demonstrate that EPCs promote fracture healing by increasing VEGF levels and thus stimulating angiogenesis, a process that is essential for early callus formation and bone regeneration

Introduction. Revision total knee arthroplasty (TKA) has been often used with a metal block augmentation for patients with poor bone quality. However, bone defects are frequently detected in revision TKA used with metal block augmentation. This study focused on identification of a potential possibility of the bone defect occurrence through the evaluation of the strain distribution on the cortical bone of the tibia implanted revision TKA with metal block augmentation, during high deep flexion. Materials and Methods. Composite tibia finite element (FE) model was developed and revision TKA FE model with a metal block augmentation (Baseplate size #5 44AP/67ML, Spacer size #5 44AP/67ML, Stem size Φ9, L30, Augment #5 44AP/67ML thickness 5mm) was integrated with the composite tibia FE model. 0°, 30° 60°, 90°, 120° and 140° flexion positions were then considered with femoral rollback phenomenon [Fig 1.A]. A compressive load of 1,600N through the femoral component was applied to the composite tibia FE model integrated with the tibia component, sharing by the medial and lateral condyles, simulating a stance phase before toe-off [Fig 1.B]. Results and Discussions. The strain distribution on the cortical bone of the tibia was shown in [Fig 2]. The results showed that the strains on the posterior region were gradually increased from extension to high deep of the knee joint and generally larger than the other regions. This fact was favorably corresponded to the femoral rollback phenomenon in the knee joint, showing a good accuracy of our FE model. In contrast to the results on the posterior region, the strains on the medial region were gradually decreased after 60° or 90° flexion position and relatively lower than the other regions. Particularly, the strains on the medial region were generally lower than 50–100 µstrain, which is known as critical value range able to inducing bone loss, during high deep flexion. This fact indicate that a potential possibility of bone defect occurrence in revision TKA used with a metal block augmentation may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. This study may be valuable by identifying for the first time a potential possibility of the bone defect occurrence through evaluation of the strain distribution beneath metal block augmentation in revision TKA used with a metal block augmentation during high deep flexion. Conclusions. A potential possibility of bone defect occurrence in revision TKA used with a metal block augmentation may be dependent on loading patterns applied on the knee joint related to personal lifestyle history. Particularly, it may be relatively increased in patients who are frequently exposed to a personal lifestyle history with the loading conditions of the high flexion. Acknowledgements. This study was supported by a grant from the New Technology Product Evaluation Technical Research project, Ministry of Food and Drug Safety (MFDS), Republic of Korea

The use of new megaprosthesis for massive bone loss is an option for the replacement of skeletal segments. There are several clinical scenarios that can be associated with this situation including severe trauma with multiple failed osteosynthesis with a non union or with a previous prosthetic replacement of a neighbouring joint; multiple revision of arthroplasty with or without infections or large resections of tumours. The aim of this work is to evaluate retrospectively both clinical and radiological outcomes and any complications in patients treated with megaprosthesis in SEPTIC BONE DEFECTS in our Hospital from February 2012 to January 2015. From February 2012 to January 2014 a total of 20 patients were treated with mono-and bi-articular megaprosthesis subdivided as follows: 4 proximal femur, 11 distal femur, 3 total femur, 1 total humerus and 1 proximal humerus. Clinical and serial radiographic evaluations were performed at 6 weeks, 3, 6, 12, 18 and 24 months. Blood parameters with CRP and ESR were monitored for at least 2 months. The mean follow-up of patients was about 24.4 months (range 5 months to 31 months). The mean age of the patients was 53 years (range 37–80years). Of the patients 20, 9 were female and 11 were male. The aetiology was: 11 septic non unions, 3 infected TKA, 4 infected THR and 2 infected tumor prostheses. We have evaluated retrospectively both clinical and radiological outcomes of 20 patients. They had large bone defects that threatened the viability of the limb. They were treated with megaprosthesis. Although the mean length of follow-up was only 24.4 months they showed encouraging clinical results, with good articulation of the segments, no somato-sensory or motor deficit and acceptable functional recovery. There were three cases of dislocation, one case with rifampicin toxicity, one case with acute prosthetic infection (case that needed debridement and one case with chronic oral antimicrobial. Megaprosthesis provides a valuable opportunity to restore functionality to patients with highly disabling diseases. The number of complications is not depreciable

The Masquelet or induced membrane technique (IMT) is a two-stage surgical procedure used for the treatment of segmental bone defects. In this technique, the defect is first filled with a polymethyl methacrylate (PMMA) spacer, which triggers the formation of a membrane that will encapsulate the defect. During the second surgery, the spacer is carefully removed and replaced by autologous bone graft while preserving the membrane. This membrane is vascularized, contains growth factors, and provides mechanical stability to the graft, all of which are assumed to prevent graft resorption and promote bone healing. The technique is gaining in popularity and several variations have been introduced in the clinical practice. For instance, orthopaedic surgeons now often include antibiotics in the spacer to treat or prevent infection. However, the consequences of this approach on the properties of the induce membrane are not fully understood. Accordingly, in a small animal model, this study aimed to determine the impact on the induced membrane of impregnating spacers with antibiotics frequently used in the IMT. We surgically created a five-mm segmental defect in the right femur of 25 adult male Sprague Dawley rats. The bone was stabilized with a plate and screws before filling the defect with a PMMA spacer. Animals were divided into five equal groups according to the type and dose of antibiotics impregnated in the spacer: A) no antibiotic (control), B) low-dose tobramycin (1.2 g/40 g of PMMA), C) low-dose vancomycin (1 g/40 g of PMMA), D) high-dose tobramycin (3.6 g/40 g of PMMA), E) high-dose vancomycin (3 g/40 g of PMMA). The animals were euthanized three weeks after surgery and the induced membranes were collected and divided for analysis. We assessed the expression of selected genes (Alpl, Ctgf, Runx2, Tgfb1, Vegfa) within the membrane by quantitative real-time PCR. Moreover, frozen sections of the specimens were used to quantify vascularity by immunohistochemistry (CD31 antigen), proliferative cells by immunofluorescence (Ki-67 antigen), and membrane thickness. Microscopic images of the entire tissue sections were taken and analyzed using FIJI software. Finally, we measured the concentration of vascular endothelial growth factor (VEGF) in the membranes by ELISA. No significant difference was found among the groups regarding the expression of genes related to osteogenesis (Alpl, Runx2), angiogenesis (Vegfa), or synthesis of extracellular matrix (Ctgf, Tgfb1) (n = four or five). Similarly, the density of proliferative cells and blood vessels within the membrane, as well as the membrane thickness, did not vary substantially between the control, low-dose, or high-dose antibiotic groups (n = four or five). The concentration of VEGF was also not significantly influenced by the treatment received (n = four or five). The addition of tobramycin or vancomycin to the spacer, at the defined low and high doses, does not significantly alter the bioactive characteristics of the membrane. These results suggest that orthopaedic surgeons could use antibiotic-impregnated spacers for the IMT without compromising the induced membrane and potentially bone healing

Introduction. Diaphyseal bone defect represents a significant problem for orthopaedic surgeons and patients. Bone is a complex tissue whose structure and function depend strictly on ultrastructural organization of its components: cells, organic (extracellular matrix, ECM) and inorganic components. The purpose of this study was to evaluate bone regeneration in a critical diaphyseal defect treated by implantation of a magnetic scaffold fixed by hybrid system (magnetic and mechanical), supplied through nanoparticle-magnetic (MNP) functionalized with Vascular Endothelial-Growth-Factor-(VEGF) and magnetic-guiding. Methods. A critical long bone defect was created in 8 sheep metatarsus diaphysis: it was 20.0 mm in length; the medullary canal was reamed till 8.00 mm of inner diameter. Then a 8.00 mm diameter magnetic rod was fitted into proximal medullary canal (10 mm in length). After that a scaffold made of Hydroxyapatite (outer diameter 17.00 mm) that incorporates magnetite (HA/Mgn 90/10) was implanted to fill critical long bone defect. A magnetic rod (6.00 mm diameter) was firmly incorporated at proximal side into the scaffold. Both magnets had 10 mm length. To give stability to the complex bone-scaffold-bone a plate was used as a bridge; it was fixed proximally by 2 screws and distally by 3 screws. Scaffolds biocompatibility was previously assessed in vitro using human osteoblast-like cells. Magnetic forces through scaffold were calculated by finite element software (COMSOL Multiphysics, AC/DC Model). One week after surgery, magnetic nanoparticles functionalized with VEGF were injected at the mid portion of the scaffold using a cutaneous marker positioned during surgery as reference point in 4 sheep; other sheep were used as control group. After sixteen weeks, sheep were sacrificed to analyze metatarsi. Macroscopical, radiological and microCT examinations were performed. Results. Samples obtained didn't show any inflammatory tissue around the scaffold and revealed bone tissue formation inside pores of the scaffolds and we could see also complete coverage of the scaffolds. Formation of new bone tissue was more evident at magnetized bone-scaffold interface. X-rays showed a good integration of the scaffold with a good healing process of critical bone defect: new cortical bone formation seemed to be present, recreating continuity of metatarsus diaphysis. No signs of scaffold mobilization was showed (Fig. 1). All these datas were confirmed by the microCT: new bone formation inside the scaffolds was evident, in particular at proximal bone-scaffold interface, where permanent magnet were present (Fig. 2). These preliminary results lead our research to exploiting magnetic forces to stimulate bone formation, as attested in both in vitro and in vivo models and to improve fixation at bone scaffold interface, as calculated by finite element software, and moreover to guide targeted drug delivery without functionalized magnetic nanoparticles dissemination in all body

Aim. Which patients is bone-defect-reconstruction with the Masquelet-technique suitable and which problems did we see?. Method. From 11/2011 to 4/2016 we treated 49 Patients (12f/37m) with bone-defects up to 150mm after septic complications with the Masquelet-technique. We had infected-non-unions of upper and lower extremity, chronic osteomyelitis, infected knee-arthrodesis and upper-ancle-empyema. On average the patients were 48 (8–74) years old. The mean bone-defect-size was 60 mm (25–150). From other hospitals came 47 of the 49 patient, where they had up to 20 (mean 4,9) operations caused by the infection. The time before transfer to our hospital was on average 177days (6–720). 40 patients receaved flaps because of soft tissue-defects (12 free flaps, 28 local flaps). 21 patients suffered a polytrauma. In 8 cases the femur, in 4 cases a knee-arthrodesis, in 34 cases tibia, in 2 cases humerus and in 1 case the ulna were infected resulting in bone defects. Indication for the Masquelet-technique was low-/incompliance in 35 cases due to higher grade of traumatic brain injury and polytrauma and difficult soft-tissue conditions, in 9 times problems with segment-transport and in 5 cases as dead space management. Positive microbial detection succeeded in 32 patients at the first operation. Mainly we found difficult to treat bacteria. After treating the infection with radical sequestrectomy, removal of foreign bodies and filling the defect with antibiotic loaded cement spacer and external fixation we removed the spacer6–8 weeks later and filled the defect with bone graft. In 23 cases we stabilized the defect then with an internal angle stable plate. All patients were examined clinically and radiologically every 4–6 weeks in our outpatient-department until full weight bearing, later every 3 months. Results. In 41 of 49 cases the infection was clinically treated successfully. 21 patients are allowed for full weight bearing (all with secondary internal plates). There were 8 recurrences of infection, 22 instabilities needing internal stabilization and further bone graft. We saw “Plate-breaks” in 4 cases. 2 patients underwent amputation. Conclusions. For patients with low-/incompliance for various reasons and for those with difficult soft tissue conditions following flaps the Masquelet technique is a valuable alternative to the normal bone graft and to the segment transport. The stiffness of the new Masquelet bone like a rod is a problem. Internal fixation is often necessary

To document early in-vivo concentrations of gentamicin in plasma and drain fluid after bone defect reconstruction using a gentamicin-eluting bone graft substitute. Introduction. Reconstruction of bone defects after surgical bone tumor resection is associated with an increased risk of infection and some surgeons therefore prefer extended antibiotic prophylaxis in these patients. A gentamicin-eluting bone graft substitute consisting of sulphate and apatite has been shown to be effective for treatment of osteomyelitis(1) and may be a valuable addition to the therapeutic and/or prophylactic antibiotic regime for this and many other indications. We performed a prospective pilot study from December 2014 to February 2015 in 7 patients (M/F: 4/3, mean age 51 (37–79) years) who underwent bone defect reconstruction with a gentamicin-eluting bone graft substitute (CERAMENT™|G – BONESUPPORT AB) containing 175 mg gentamicin per 10 mL. Indications for surgery were metastatic bone disease (n=3, proximal humerus), giant cell tumor (n=2, distal femur), aseptic prosthetic loosening (n=1, knee) and chondroid tumor (n=1, distal femur). Additional endoprosthetic reconstruction with a tumor prosthesis was performed in 3 patients (2 proximal humerus and 1 distal femur). Drain fluid and plasma was collected immediately postoperatively and each postoperative day until the drain was removed. In 2 cases we were unable to collect drain fluid directly postoperatively due to minimal fluid production. Gentamicin concentrations were analyzed using an antibody technique (Indiko™ – Thermo Scientific). A mean of 14 (10–20) mL gentamicin-eluting bone graft substitute was used, either alone or in combination with cancellous allograft and/or a bone graft substitute not containing gentamicin (CERAMENT™|BVF – BONESUPPORT AB). Mean drain fluid concentrations of gentamicin were 1200 (723–2100) mg/L immediately postoperative (0–2 hours), 1054 (300–1999) mg/L on day 1 (17–23 hours) and 509 (38–1000) mg/L on day 2 (39–45 hours). Mean plasma concentrations of gentamicin were 1.26 (1.08–1.42) mg/L immediately postoperative, 0.95 (0.25–2.06) mg/L on day 1 and 0.56 (0.20–0.88) mg/L on day 2. Discussion. As gentamicin induces a concentration-dependent bacterial killing effect, the obviously high local peak concentrations of gentamicin found in this study would be expected to deliver a substantial prophylactic effect after long operations with an increased risk of intraoperative bacterial contamination. Local implantation of a gentamicin-eluting bone graft substitute for bone defect reconstruction results in high concentrations of gentamicin in the drain fluid in the first postoperative days and low plasma concentrations

Aim & introduction. Infected knee with bone defect resulting from failed total knee arthroplasty (TKA) or destruction of native joint can necessitate restoration of segmental defect and arthrodesis for therapy of infection and maintenance of walking ability. In segmental knee defect external fixators or KAFO are not suitable, not comfortable and poor tolerated by elderly patients. Both custom-made Femoro-Tibial Nail (FTN) combined with acrylic cement spacer and Knee Arthrodesis Nail System (KANS) offer maintenance of supportive function of extremity and avoidance of leg length discrepance after removal of TKA. Method. The group consists of 13 patients. In 12 cases knee arthrodesis have been performed due to infection with bone defect after removal of infected TKA, and in 1case due to inflammatory destruction of native knee joint. In 7 cases FTN with ALAC spacer and in 6 cases KANS (5 cases Orthopedic Salvage System-OSS; 1 case Link KANS) was used. In cases treated with FTN the gap between distal femur and proximal tibia was filled with hand-made acrylic cement spacer loaded with selected antibiotic (2g per 40 g cement) so that the spacer finally gained cylindrical shape. Results. Stable knee was noted after 7 years in 4 of 7 knees treated with FTN with ALAC spacer and after 2 years in 6 of 6 after KANS. Infection free knee was gained after 7 years in 4 of 7 cases treated with FTN with ALAC spacer and after 2 years in 5 of 6 cases treated with KANS. Amputation was necessary after 6 years in 3 of 7 cases treated with FTN with ALAC spacer and after 2 years in none case treated with KANS. Complications occurred in 2 cases after FTN with ALAC spacer (1x: FTN breackage, 1x: stress fracture of femoral neck) and in 1 case after KANS (OSS implant failure). Replacement of FTN nail and cement spacer in 1 case and respectively revision of OSS KANS in 1 cases was performed. Conclusions. Compared with the KANS, custom-made FTN combined with ALAC spacer proved to be effective up to 6 years, but shoved higher rate of complications and amputations after 6 years. It can be considered as a temporary low-cost salvage procedure for infected TKA with segmental bone defect as 1. st. stage in two-stage arthrodesis for infected knee prosthesis

Treatment of segmental bone loss remains a major challenge in orthopaedic surgery. This study evaluated the healing potential of a series of highly porous tissue engineering scaffolds with the current clinical gold standard. We compare healing of collagen-glycosaminoglycan (CG) and collagen micro-hydroxyapatite (CHA) scaffolds, with and without recombinant bone morphogenetic protein-2 (BMP2), with autogenous bone graft (ABG) in the healing of a 15mm rabbit radius defect, which were filled with either CG scaffold, CHA scaffold, CG-BMP2, CHA-BMP2 or ABG. Serial radiographs and micro-computed tomography (µCT) at six week radiographs demonstrated complete defect bridging with callus using CHA and CG-BMP2 while the CHA-BMP2 was already in an advanced state of healing with cortical remodeling. By sixteen weeks CHA, CG-BMP2 and ABG all had advanced healing with cortical remodeling while CHA-BMP2 had complete anatomic healing. Quantitative histomorphometry values demonstrated similarly high healing levels of healing in CHA, CG-BMP2 and ABG with highest overall values in the CHA-BMP2 group. Thus, treatment of a critical sized, weight bearing, rabbit radius defect with a CHA scaffold can result in full cortical bridging with medullary cavity development. In addition, a CHA-BMP2 combination can result in fully mature, anatomic healing. The use of an off-the-shelf CHA scaffold for direct surgical placement into a defect site may be an effective bone graft substitute in the treatment of skeletal defects. The ease of manufacture, storage and peri-operative preparation may offer an alternative to traditional strategies, as well as to more recent BMP2 devices. This study provides clear evidence that CHA scaffolds can perform as well as autogenous bone grafts and supports their use as a viable alternative. Where the use of BMP2 may be desirable, these materials provide an ideal delivery mechanism and using a very low (near physiological) dose, healing superior to autogenous graft may be achieved.