A ruptura do ligamento cruzado cranial (RLCCr) é a principal causa de claudicação em cães, podendo ocorrer devido à causas traumáticas ou degenerativas. Apesar da ampla variedade de técnicas cirúrgicas disponíveis, o tratamento ideal para esta condição ortopédica permanece indeterminado. Nas últimas décadas, foram desenvolvidas técnicas que evitam a movimentação anormal do joelho por conseguir estabilidade dinâmica através da alteração da geometria óssea e, dentre elas, destacam-se as técnicas de osteotomia para nivelamento do platô tibial (TPLO) e a osteotomia para avanço da tuberosidade tibial (TTA). São poucos os estudos clínicos que avaliam o joelho e sua funcionalidade após as cirurgias de TPLO e TTA. O apoio precoce do membro no pós-operatório é uma das principais vantagens da TPLO e TTA, e este apoio pode ser avaliado de forma subjetiva (tabela com graus de claudicação), mas a análise cinética do movimento em plataforma de pressão destaca-se por proporcionar mensuração objetiva do uso do membro durante a deambulação. O objetivo deste trabalho é comparar as técnicas de osteotomia para avanço da tuberosidade tibial (TTA) e osteotomia para nivelamento do platô tibial (TPLO) na estabilização de joelhos de cães com ruptura de ligamento cruzado cranial, por avaliação subjetiva e objetiva através da análise em plataforma de pressão (baropodometria). Foram avaliados 27 cães adultos acima de 20 quilos e com RLCCr unilateral, submetidos aos procedimentos de TTA (12 cães) ou TPLO (15 cães). Estes pacientes foram avaliados no período pré-operatório e aos 14, 30, 60 e 90 dias de pós-operatório com tabela de graduação da claudicação (dois Médicos Veterinários), escala de análise visual (deambulação pelo proprietário), exames radiográficos mensais (consolidação da osteotomia), tabela de graduação da recuperação do uso do membro (proprietário) e apoio em plataforma de pressão (baropodometria). Os animais foram separados nos grupos de acordo com a angulação do platô tibial (APT) e, baseado na recomendação clínica, foi utilizado TPLO para qualquer APT e TTA para APT de até 27°. Em ambos os grupos foi observada recuperação funcional do membro operado estatisticamente significativa, tanto nas avaliações subjetivas, como na avaliação objetiva em plataforma de pressão. Em decorrência da recomendação clínica para TTA, houve diferença significativa entre os grupos com relação ao ângulo do platô tibial (28,13° para TPLO e 22,33° para TTA), porém este foi corrigido com o teste de covariância. Não houve diferença entre os grupos na recuperação do apoio do membro com RLCCr, tanto na avaliação subjetiva como na avaliação objetiva em plataforma de pressão. Concluise que os procedimentos cirúrgicos de TPLO e TTA foram eficientes em promover melhora do apoio em cães com ruptura do ligamento cruzado cranial unilateral. / Cranial cruciate ligament rupture is the major cause of lameness in dogs and can occur due to degenerative or traumatic causes. Despite the wide variety of surgical techniques available, the ideal treatment for this orthopedic condition remains undetermined. Currently techniques have been developed to prevent abnormal movement of the stifle. Dynamic stability is achieved by changing the bone geometry by techniques like tibial plateau leveling osteotomy (TPLO) and osteotomy to tibial tuberosity advancement (TTA). One of the main advantages of TPLO and TTA is the early weight-bearing in postoperative period, which can be evaluated subjectively. But the locomotion kinetic analysis in pressure platform is a more objective measurement in the use of the limb during walking. The objective of this study is to compare the techniques of tibial tuberosity advancement (TTA) and tibial plateau leveling osteotomy (TPLO) in stabilizing dogs stifles with cranial cruciate ligament deficiency in one limb. Evaluation will be done with subjective and objective assessment via analysis in pressure platform (baropodometry). We evaluated 27 adult dogs over 20 Kg with unilateral or bilateral cranial cruciate ligament rupture. They were underwent to TTA (12 dogs) and TPLO (15 dogs). These patients were evaluated in the preoperative period and at 14, 30, 60 and 90 days postoperatively focus on claudication (two veterinarians - grade scale), visual analysis scale (weightbearing - owner), radiographs (osteotomy healing), recovery degree of the function (owner) and on pressure platform (baropodometry). We evaluated 27 adult dogs with 20 kilos at least and unilateral cranial cruciate ligament deficience. They were subjected to procedures TTA (12 dogs) or TPLO (15 dogs). These patients were evaluated in the preoperative period and at 14, 30, 60 and 90 days after surgery, with postoperative lameness grading system (two veterinarians), scale of visual analysis (owner), radiographic exam (osteotomy healing), recovery grading system (owner) and pressure platform (baropodometry). The animals were divided into groups according to the the tibial plateau angle (TPA) and based on clinical recommendation we used TPLO in all patients and TTA in those patients that had TPA less than 27°. In both groups we observed statistically significant recovery, both in subjective evaluations and objective assessment. Due to the clinical recommendation for TTA, there was significant difference among groups in respect to the tibial plateau slope (28.13 for TPLO and 22.33 for TTA), but It was corrected with the covariance test. There was no difference between groups in recovery of the surgery. We conclude that TPLO and TTA were effective in promoting improved support in dogs with cranial cruciate ligament deficience.

Pure magnesium (Mg) and its alloys with calcium (Ca) and both Ca and zinc (Zn) have potential as bioresorbable bone implant materials provided the corrosion rate can be controlled. Thus, corrosion behaviour was investigated for pure Mg, Mg-2Ca, and Mg-2Ca-1Zn cast alloys subjected to either no heat treatment or to solutionizing and aging heat treatment. In addition, corrosion behaviour was investigated for surface modifications involving the deposition of silver (Ag) nanoparticles. These materials and constructs were all nominally biocompatible in that they would not elicit a strong and immediate adverse tissue reaction when implanted in bone. Static immersion tests in Hanks’ balanced salt solution were performed to evaluate the corrosion behaviour. The Mg-2Ca alloy exhibited the highest corrosion rate when compared with pure Mg and Mg-2Ca-1Zn for any length of immersion time. For short immersion times (48 hours), solutionizing followed by natural aging reduced the corrosion rate of Mg-2Ca alloy, but this heat treatment did not seem to have an effect on the corrosion rate of Mg-2Ca-1Zn alloy. As well, for short immersion times (48 hours), solutionizing and artificial aging also did not seem to have a large effect on corrosion rates for either Mg-2Ca or Mg-2Ca-1Zn, when compared to solutionizing and natural aging. Corrosion behaviour of surface-modified samples was sensitive to certain features of the Ag depositions. It was found that when the deposited Ag tracks were thick and wide, the corrosion rate of Ag-deposited samples increased significantly when compared to samples without any Ag deposition. However, when the Ag tracks were thinner and somewhat narrower, the corrosion rate did not appear to be much higher than that of samples without Ag deposition. Therefore, controlled Ag deposition may not be too detrimental to the corrosion behaviour of Mg and Mg alloys. The corrosion product morphology appeared to be similar for both the samples deposited with Ag and samples without any Ag. Needle-like formations were observed in small areas on the corroded surfaces. X-ray diffraction revealed Mg(OH)₂ as the main corrosion product. Because energy dispersive X-ray analysis consistently revealed multiple elements in the corrosion products (such as Mg, O, Ca, P, small amounts of C, and sometimes Cl), it was concluded that other compounds (possibly hydroxyapatite, magnesium chloride, and/or magnesium- and calcium-containing phosphates) may have formed in addition to the Mg(OH)₂.

Purpose: To highlight the histopathological characteristics of the skin in congenital clubfoot and correlate the clinical findings in clubfoot with the changes in the dermal layers. Materials and methods: One hundred skin specimens, from 77 infants (6 to 12 months), were studied between 2004 and 2008. Using the Pirani scoring system, the clinical severity was recorded. The mobility of the skin and the correctability of the medial ray were assessed clinically. A skin specimen (1cm x 1mm) was taken from the medial side of the foot at surgery following failed plaster treatment. The layers were studied under light microscopy. The thickness of the dermis and the histopathological features of clubfoot skin were compared with 10 normal skin specimens. Results: The dermis of clubfoot skin showed significant fibrosis with thick bundles of collagen fibres (P = .001) on Haematoxylin and Eosin staining (H&E). The dermal thickness ranged between 1.0mm and 5.2mm in clubfoot skin, compared with controls (0.64-1.28mm). Fibrosis extended into the subcutis in a septolobular fashion in 95% of the cases. Significant atrophy of eccrine glands was seen in 98% (P = .001). Hair follicles were absent in 78%. The elastic fibres of clubfoot skin, stained with Elastic van Gieson staining (EVG), showed hypertrophy in varying degrees in all skin specimens. They were fragmented, with loss of their parallel arrangement. There was no significant inflammatory reaction in the dermis. The Pirani score was significantly increased (mean 7.8). Discussion: Fibrosis and thickening of the dermis were the most significant histopathological features of the clubfoot skin. The elastic fibres were also abnormal. There was atrophy of the skin appendages due to the fibrosis. There was a strong correlation between the Pirani score and the severity of the deformity(P 0.016). The cases with poor outcome had a higher score than those with a satisfactory outcome.Lack of a significant inflammatory reaction suggests that neither the serial manipulations of the foot, nor the repeated plaster cast changes, were responsible for the dermal fibrosis, which is probably present from birth and contributes to the deformity. / Thesis (Ph.D.)-University of KwaZulu-Natal, Durban, 2012.

Pure magnesium (Mg) and its alloys with calcium (Ca) and both Ca and zinc (Zn) have potential as bioresorbable bone implant materials provided the corrosion rate can be controlled. Thus, corrosion behaviour was investigated for pure Mg, Mg-2Ca, and Mg-2Ca-1Zn cast alloys subjected to either no heat treatment or to solutionizing and aging heat treatment. In addition, corrosion behaviour was investigated for surface modifications involving the deposition of silver (Ag) nanoparticles. These materials and constructs were all nominally biocompatible in that they would not elicit a strong and immediate adverse tissue reaction when implanted in bone. Static immersion tests in Hanks’ balanced salt solution were performed to evaluate the corrosion behaviour. The Mg-2Ca alloy exhibited the highest corrosion rate when compared with pure Mg and Mg-2Ca-1Zn for any length of immersion time. For short immersion times (48 hours), solutionizing followed by natural aging reduced the corrosion rate of Mg-2Ca alloy, but this heat treatment did not seem to have an effect on the corrosion rate of Mg-2Ca-1Zn alloy. As well, for short immersion times (48 hours), solutionizing and artificial aging also did not seem to have a large effect on corrosion rates for either Mg-2Ca or Mg-2Ca-1Zn, when compared to solutionizing and natural aging. Corrosion behaviour of surface-modified samples was sensitive to certain features of the Ag depositions. It was found that when the deposited Ag tracks were thick and wide, the corrosion rate of Ag-deposited samples increased significantly when compared to samples without any Ag deposition. However, when the Ag tracks were thinner and somewhat narrower, the corrosion rate did not appear to be much higher than that of samples without Ag deposition. Therefore, controlled Ag deposition may not be too detrimental to the corrosion behaviour of Mg and Mg alloys. The corrosion product morphology appeared to be similar for both the samples deposited with Ag and samples without any Ag. Needle-like formations were observed in small areas on the corroded surfaces. X-ray diffraction revealed Mg(OH)₂ as the main corrosion product. Because energy dispersive X-ray analysis consistently revealed multiple elements in the corrosion products (such as Mg, O, Ca, P, small amounts of C, and sometimes Cl), it was concluded that other compounds (possibly hydroxyapatite, magnesium chloride, and/or magnesium- and calcium-containing phosphates) may have formed in addition to the Mg(OH)₂.

- / -

- / -

- / -

PURPOSE: The goal of this thesis research project is to evaluate and compare post-operative complications among patients, who underwent short and long segment Anterior Cervical Discectomy/Corpectomy and Fusion (ACDF/ACCF). METHODS: Retrospective cohort study design allowed for evaluation of series of variables (age, sex, diagnosis, general post-operative outcome, and complications) while comparing them between the short and long segment groups. RESULTS: Patients within both cohorts tended to experience similar complications, except pseudarthrosis and adjacent segment disease, which both were more prevalent in the long segment group. Diagnosis or short versus long segment length did not have an effect on the general post-operative outcome. One-level ACDF patients were younger than multilevel ACDF surgery patients. Dysphagia was more likely to occur in older patients, with the risk of dysphagia incidence increased by 7% with each year of patient’s age. CONCLUSIONS: Study indicated that longer segment ACDF/ACCF does not carry higher risk of complications incidence than short segment treatment. Further studies are advised to increase generalizability of these results.

Parathyroid hormone is a vital mediator of bone metabolism and studies have shown that exogenous treatment can enhance the fracture repair process in murine models. Bone remodeling is a complex process that necessitates multiple molecular and cellular interactions that are affected by genetic variations. These differences contribute to both histological and whole organ level differences of fracture healing. This study was performed to determine the effect of genetic variability of fracture healing in mice treated with parathyroid hormone during two time windows. The first window was the first 14-day period post fracture associated with chondrogensis and the second was the day 15 to day 28 post fracture, which is associated with osteogenesis. Three inbred strains of mice A/J (AJ), C57BL/6J (B6), and C3H/HeJ (C3) that have material and structural differences in bone quality were given Femoral shaft fractures and healing was evaluated at different time points post fracture using quantitative real-time polymerase chain reaction (qRT-PCR) and qualitative radiographic analysis. Chondrogenic genes Sox9, ColIIa, aggrecan, and ColXa and osteogenic genes ostrix, osteocalcin, BSP, and DMP1 were examined. The temporal analysis of mRNA expression revealed that PTH treatment given in the first 14 days post fracture enhanced osteogenic and chondrogenic expression in B6 mice, but hindered expression in AJ mice. Treatment with PTH from post fracture day 14 to day 28 greatly affected the osteogenic expression of B6 mice, but had little affect on other animals. Radiographic analysis showed that each strain presents callus formation at approximately day 7 and reaches maximum size at day 21 post fracture. Additionally B6 mice appear with the largest callus and AJ the smallest. Taken together, these results are consistent with past studies in showing that different strains of mice express a unique temporal and mRNA expression pattern of chondrogenic and osteogenic differentiation. Furthermore, these variations affect the biomechanical properties of the fracture callus during bone remodeling.

Bones have a large capacity for repair and regeneration after an injury. 5-10% of the nearly 8 million fractures that occur every year in the United States do not heal properly. Bone repair and regeneration is a complex process that utilizes molecular and cellular interactions to return to its original structure. Phosphate is essential for healthy bone growth and when phosphate deficient it has been shown to impair the process of fracture healing. It is unknown if replenishing phosphate to the diet will help return the injured bone to its original properties. Some of the differences in fracture repair may be due to genetic variability that contributes to morphology of bone and fracture healing. This study was carried out to assess how genetic variability affects the process of fracture healing. To determine how genetic differences interact with phosphate deficiency fractures were generated in three different inbred mouse strain (A/J (AJ), C57BL/6J (B6), C3H/HeJ (C3)) that had previously been shown to have different endochondral bone formation. Animals were placed on a phosphate restricted diet two days prior to fracture, and was maintained for 15 days, which covered the normal duration of endochondral bone development. To determine if replenishing phosphate in the diet could recover the normal healing, phosphate was returned to the diet after 15 days. There was also control groups that were on a regular diet for the entire time of the study, which was used for comparison. Micro-computed tomography (micro-CT), biomechanical torsion testing, and contrast enhanced micro-computed tomography (CECT) were methods used to asses the properties of the callus over the course of fracture healing. Micro-CT and mechanical test results showed that there were significant differences within AJ, B6, and C3 strains of mice at the various post-operative day (POD) time points. Results from micro-CT data showed that as the POD time point increased there was an increase in the amount of mineralized tissue and a decrease in fracture callus. These results were confirmed by with the increase in strength measurements from mechanical testing conclusions. Further, the fracture callus is less rigid at the early time points and as the fracture callus becomes mineralized there is an increase in the rigidity measures. Other measures of mechanical properties showed that there were significant differences in the B6 and C3 strains of mice among the various POD time points and control and phosphate restricted diets. Assessing cartilage content via CECT showed that there were significant differences in the control and phosphate restricted diets at POD 14, however many of these differences were recovered at the later time points. Visualization of the fracture callus using CECT confirmed that there was diminishing cartilage present in the fracture callus. These results provide insight into the fracture healing process and much information about the return of stability and strength to the fractured bone. Taken together, the outcomes of this study indicate that the bones heal and mechanical strength is recovered once the phosphate has been added back into the diet.