Thermal osteonecrosis is a side effect when used Kirschner (K) wires and drills in orthopaedic surgeries. This osteonecrosis may endanger the fixation. Orthopaedic surgeons sometimes have to use unsharpened K-wires in emergent surgery. The thermal effect of used and unsharpened K wire is ambiguous to the bone. This experimental study aims to assess the thermal osteonecrosis while drilling bone with three different types of K-wires especially a previously used unsharpened wire and its thermographic measurements correlation. Two different speeds of rotation were chosen to investigate the effect of speed on thermal necrosis to the bone. A total of 16 New Zealand white rabbits weighing a mean of 2.90 kg (2.70 – 3.30 kg) were used. All rabbits were operated under general anaesthesia in a sterile operating room. Firstly, 4 cm longitudinal lateral approach was used to the right femur and then the femur was drilled with 1.0 mm trochar tip, spade tip and previously used unsharpened K-wires and 1.0 mm drill bit at 1450 rpm speed. Left femur was drilled with same three type K-wires and drill bit at 330 rpm speed. One cm distance was left among four penetrations on the femur. The thermal changes were recorded by Flir® E6 Thermal Camera from 50 cm distance and 30-degree angle. Thermographic measurements saved for every drilling process and recorded for the highest temperature (°C) during the drilling. All subjects were sacrificed post-operatively on the eighth day and specimens were prepared for the histological examination. The results of osteonecrosis assessment score and thermographic correlation were evaluated statistically. Histological specimens were evaluated by the scoring of osteonecrosis, osteoblastic activity, haemorrhage, microfracture and inflammation. Results were graded semi-quantitatively as none, moderate or severe for osteonecrosis, haemorrhage and inflammation. The microfracture and osteoblastic activity were evaluated as present or absent. There was no meaningful correlation between osteonecrosis and the drilling speed (p=0.108). There was less microfracture zone which was drilled with trochar tip K-wires at 1450 rpm speed (p=0.017). And the drilling temperature of trochar tip K-wires was higher than the others(p=0.001). Despite this evaluation, osteonecrosis zone of spade and unsharpened tip K-wires were more than trochar tip K-wires (p=0.039). The drill bit at 330 rpm caused the least osteonecrosis and haemorrhage and respectfully the lowest drilling temperature (p=0,001). The osteoblastic activity shows no difference between the groups. (p=0,122; 0,636;0.289). On the contrary to the literature, our experiment showed that there is no meaningful correlation between osteonecrosis score and temperature produced by drilling. The histological assessment showed the osteonecrosis during short drilling time but, not clarify the relation with drilling temperature. Eventually, the osteonecrosis showed a positive correlation with drilling time independently of drilling temperature at 330 rpm. (p=0,042) These results show that we need more studies to understand about osteonecrosis and its relationship with drilling heat temperature. Trochar tip K-wires creates higher drilling temperature but less osteonecrosis than a spade and unsharpened cut tip K-wires. Using unsharpened tip K-wire causes more osteonecrosis. Previously used and, unsharpened K-wires should be discarded

Introduction and Objective. In multiple trauma patients, as well as in the healing of isolated fractures (Fx) with heavy bleeding (trauma haemorrhage, TH), complications occur very often. This is particularly evident in elderly patients over 65 years of age. Since these accompanying circumstances strongly influence the clinical course of treatment, the influence of age on bone regeneration after femoral fracture and severe blood loss was investigated in this study. Materials and Methods. 12 young (17–26 weeks) and 12 old (64–72 weeks) male C57BL / 6J mice per group were examined. The fracture group Fx underwent an osteotomy after applying an external fixator. The THFx group also received blood pressure-controlled trauma hemorrhage (35 mmHg for 90 minutes) and reperfusion with Ringer's solution for 30 minutes. The Sham group received only the catheter and one external fixator. μCT scans of the femora were performed in vivo after 2 weeks and ex vivo after 3 weeks. Histological and biomechanical examinations were also carried out. The statistical significance was set at p ≤ 0.05. The non-normally distributed data were analyzed using the Mann-Whitney-U or Kruskal-Wallis test. Results. The histology showed less mineralized bone in the fracture gap in old animals of the Fx (25.41% [1.68%]) and THFx groups (25.50% [4.07%]) compared with the young ones (34.20% [6.36%], p = 0.003; 34.31% [5.12%], p=0.009). Moreover, a severe blood loss lead to more cartilage in both young (6.91% [5.08%]) and old animals (4.17% [1.42%]) compared to animals with only a fracture (2, 45% [1.04%], p=0.004; 2.95% [1.12%], p=0.032). In old animals (11.37 / nm. 2. [17.17 / nm. 2. ]) in contrast the young mice with an isolated fracture (33.6/nm. 2. [8.83/nm. 2. ]) fewer osteoclasts were present (p=0.009). Therefore, the severe blood loss further reduced the number of osteoclasts only in young animals (16.83/nm. 2. [6.07/nm. 2. ]) (p=0.004). In the in vivo μCT, after 2 weeks, a lower volume of bone, cortex and callus was found in old THFx animals (3.14 mm. 3. [0.64 mm. 3. ]); 1.01 mm. 3. [0.04 mm. 3. ]; 2.07 mm. 3. [0.57 mm. 3. ]) compared with the Fx animals (4.29 mm. 3. [0.74 mm. 3. ], p=0.008; 1.18 mm. 3. [0, 25 mm. 3. ], p=0.004; 3.02 mm. 3. [0.77 mm. 3. ], p=0.008) After 3 weeks, the ex vivo μCT scans also showed a reduced callus percentage in old THFx animals (61.18% [13.9 9%]), as well as a low number of trabeculae (1.81 mm. -1. [0.23 mm. -1. ]) compared to animals without blood loss (68.72% [15.71%], p = 0.030; 2.06mm. -1. [0.37mm. -1. ], p=0.041). In the biomechanical test, a reduced elasticity limit of the old THFx mice (7.75 N [3.33 N]) in contrast to the old Fx (10.24 N [3.32 N]) animals was shown (p=0.022). Conclusions. A severe blood loss has a higher negative effect on the healing, morphometry, and biomechanical properties of previously fractured femora in old compared to young individuals

Purpose. In patients with multiple trauma delayed fracture healing is often diagnosed, but the pathomechanisms are not well known yet. The purpose of the study is to evaluate the effect of a severe hemorrhagic shock on fracture healing in a murine model. Methods. 10 male C57BL/6N mice per group (Fx, TH, THFx, Sham) and point in time were used. The Fx-group received an osteotomy after implantation of a fixateur extern. The TH-group got a pressure controlled hemorrhagic shock with a mean arterial blood pressure of 35 mmHg over 90 minutes. Resuscitation with 4 times the shed blood volume of Ringer solution was performed. The THFx group got both. Sham-animals received the implantation of a catheter and a fixateur extern but no blood loss or osteotomy. After 1, 2, 3, 4 or 6 weeks the animals were sacrificed. For the biomechanics the bones were analyzed via X-ray, µCT and underwent a 3-point bending test. The nondecalcified histology based on slices of Technovit 9100. The signaling pathway was analyzed via RT. 2. Profiler™ PCR Array Mouse Osteoporosis, Western Blot and Quantikine ELISA for RankL and OPG. Statistical significance was set at p < 0.05. Comparisons between groups were performed using the Mann–Whitney U (Fx vs. THFx) or Kruskal-Wallis Test (other groups). Results. The experiment showed that after 1 week the bones of the Fx- and THFx-mice were macroscopically instable. After 2 weeks the Fx-group showed macroscopically a stable bridging whereas the bones of the THFx-group were partly not stable bridged. 3 weeks after surgery the bones of both groups were stable bridged. Analysis via µCT showed that trauma hemorrhage leads to decreased density of the bone and callus and also to increased share of callus per bone volume after 2 weeks. The 3-point-bending test showed that the maximum bending moment is decreased in the group THFx compared to Fx after 2 weeks. The studies of the histology showed after 2 weeks a decrease in bone and cartilage after trauma-hemorrhage by optical analysis of photographs of the slices. The analyses of the signaling pathway pointed to an involvement of the RankL/Opg and IL6 pathway. Conclusion. A hemorrhagic shock has a negative effect on fracture healing in terms of reduced density of the bone and callus, increased share of callus per bone volume, decreased maximum bending moment, reduced mineralization of the callus and leads to changes in the RankL/Opg and IL6 pathways

Introduction and Objective. Hemorrhagic shock and fractures are the most common injuries within multiple injured patients, inducing systemic and local inflammation in NF-kappaB-dependent manner. Alcohol intoxication, showing a high incidence with severe injuries, has immunomodulatory properties and implicates NF-kappaB downregulation. However, the mechanism is largely unknown. A20 deubiquitinase is a critical negative regulator of NF-kappaB activity and inflammation. Here, we investigate the role of A20 as a modifier of NF-kappaB-driven inflammation and remote lung injury in severely injured and alcohol-intoxicated mice. Materials and Methods. Mice were randomly divided into four groups. Either sodium chloride or ethanol (35%, EtOH) was administrated by intragastral gavage one hour before trauma induction. In the trauma group, the animals underwent an osteotomy with external fracture fixation (Fx) followed by a pressure-controlled hemorrhagic shock (35±5 mmHg; 90 minutes) with subsequent resuscitation (H/R). Sham-operated animals underwent only surgical procedures. Mice were sacrificed at 24 hours. Fatty vacuoles and thus, the alcohol intoxication were evaluated by Oil red O staining of the liver. To assess the lung injury, hematoxylin eosin staining, determination of total protein concentration in bronchoalveolar lavage (BALF) and calculation of the lung injury score (LIS) were performed. Lungs were stained for neutrophil elastase, CXCL1 and active caspase-3 to determine neutrophil invasion, pro-inflammatory changes and apoptosis, respectively. The expression level of A20 was evaluated by immunofluorescence microscopy. Results. EtOH induced significant fatty changes in the liver. Fx+H/R led to trauma-induced lung injury, significantly enhancing the total protein concentration in the BALF and the histomorphological LIS compared to sham animals. In turn, EtOH reduced the lung injury in Fx+H/R. The expression of CXCL1 and activated caspase-3 as well as the pulmonary neutrophil infiltration were significantly enhanced in Fx+H/R vs. sham, whereas A20 protein expression was reduced. EtOH+Fx+H/R caused reduced pulmonary neutrophil invasion, CXCL1 expression, and apoptosis compared to Fx+H/R, whereas the A20 protein expression in the lungs was increased. Conclusions. In murine Fx+H/R trauma model, EtOH ameliorates the extent of the remote lung injury. The immunosuppressive effect may be caused by elevated pulmonary levels of A20 deubiquitase, indicating a suppression of NF-kappaB activation

Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight. Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A. 2. , nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid. This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome

Our aim was to evaluate bursal involvement at different stages of the impingement syndrome as judged by conventional histopathological examination and expression of tenascin-C, which is known to reflect active reparative processes in different tissues and disorders. Samples of subacromial bursa were taken from 33 patients with tendinitis, 11 with a partial tear and 18 with a complete tear of the rotator cuff, and from 24 control shoulders. We assessed the expression of tenascin-C, the thickness of the bursa, and the occurrence and degree of fibrosis, vascularity, haemorrhage and inflammatory cells. The expression of tenascin-C was significantly more pronounced in the complete tear group (p < 0.001) than in the partial tear, tendinitis or control groups. It was more pronounced in the tendinitis group than in the control group (p = 0.06), and there was more fibrosis in all the study groups than in the control group. The changes in the other parameters were not equally distinctive. Expression of tenascin-C did not correlate with the conventional histopathological parameters, suggesting that these markers reflect different phases of the bursal reaction. Tenascin-C seems to be a general indicator of bursal reaction, being especially pronounced at the more advanced stages of impingement and this reaction seems to be an essential part of the pathology of impingement at all its stages

Objectives

Osteophytes are products of active endochondral and intramembranous ossification, and therefore could theoretically provide significant efficacy as bone grafts. In this study, we compared the bone mineralisation effectiveness of osteophytes and cancellous bone, including their effects on secretion of growth factors and anabolic effects on osteoblasts.

The establishment of a suitable animal model of repair of the rotator cuff is difficult since the presence of a true rotator cuff anatomically appears to be restricted almost exclusively to advanced primates. Our observational study describes the healing process after repair of the cuff in a primate model. Lesions were prepared and repaired in eight ‘middle-aged’ baboons. Two each were killed at four, eight, 12 and 15 weeks post-operatively. The bone-tendon repair zones were assessed macroscopically and histologically.

Healing of the baboon supraspinatus involved a sequence of stages resulting in the reestablishment of the bone-tendon junction. It was not uniform and occurred more rapidly at the sites of suture fixation than between them. Four weeks after repair the bone-tendon healing was immature. Whereas macroscopically the repair appeared to be healed at eight weeks, the Sharpey fibres holding the repair together did not appear in any considerable number before 12 weeks. By 15 weeks, the bone-tendon junction was almost, but not quite mature.

Our results support the use of a post-operative rehabilitation programme in man which protects the surgical repair for at least 12 to 15 weeks in order to allow maturation of tendon-to-bone healing.

The stress response to trauma is the summation of the physiological response to the injury (the ‘first hit’) and by the response to any on-going physiological disturbance or subsequent trauma surgery (the ‘second hit’).

Our animal model was developed in order to allow the study of each of these components of the stress response to major trauma. High-energy, comminuted fracture of the long bones and severe soft-tissue injuries in this model resulted in a significant tropotropic (depressor) cardiovascular response, transcardiac embolism of medullary contents and activation of the coagulation system. Subsequent stabilisation of the fractures using intramedullary nails did not significantly exacerbate any of these responses.

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.

We assessed the predictive value of the macroscopic and detailed microscopic appearance of the coracoacromial ligament, subacromial bursa and rotator-cuff tendon in 20 patients undergoing subacromial decompression for impingement in the absence of full-thickness tears of the rotator cuff. Histologically, all specimens had features of degenerative change and oedema in the extracellular matrix. Inflammatory cells were seen, but there was no evidence of chronic inflammation. However, the outcome was not related to cell counts.

At three months the mean Oxford shoulder score had improved from 29.2 (20 to 40) to 39.4 (28 to 48) (p < 0.0001) and at six months to 45.5 (36 to 48) (p < 0.0001). At six months, although all patients had improved, the seven patients with a hooked acromion had done so to a less extent than those with a flat or curved acromion judged by their mean Oxford shoulder scores of 43.5 and 46.5 respectively (p = 0.046). All five patients with partial-thickness tears were within this group and demonstrated less improvement than the patients with no tear (mean Oxford shoulder scores 43.2 and 46.4, respectively, p = 0.04). These findings imply that in the presence of a partial-thickness tear subacromial decompression may require additional specific treatment to the rotator cuff if the outcome is to be improved further.

We evaluated the possible induction of a systemic immune response to increase anti-tumour activity by the re-implantation of destructive tumour tissue treated by liquid nitrogen in a murine osteosarcoma (LM8) model. The tumours were randomised to treatment by excision alone or by cryotreatment after excision. Tissue from the tumour was frozen in liquid nitrogen, thawed in distilled water and then re-implanted in the same animal. In addition, some mice received an immunological response modifier of OK-432 after treatment. We measured the levels of interferon-gamma and interleukin-12 cytokines and the cytotoxicity activity of splenocytes against murine LM8 osteosarcoma cells. The number of lung and the size of abdominal metastases were also measured.

Re-implantation of tumour tissue after cryotreatment activated immune responses and inhibited metastatic tumour growth. OK-432 synergistically enhanced the anti-tumour effect. Our results suggest that the treatment of malignant bone tumours by reconstruction using autografts containing tumours which have been treated by liquid nitrogen may be of clinical value.