The application of bone substitutes and cements has a long standing history in augmenting fractures as a complement to routine fracture fixation techniques. Nevertheless, such use is almost always in conjunction with definite means of fracture fixation such as intramedullary pins or bone plates. The idea of using biomaterials as the primary fixation bears the possibility of simultaneous fixation and bone enhancement. Intramedullary recruitment of bone cements is suggested in this study to achieve this goal. However, as the method needs primary testings in animal models before human implementation, and since the degree of ambulation is not predictable in animals, this pilot study only evaluates the outcomes regarding the feasibility and safety of this method in the presence of primary bone fixators. A number of two sheep were used in this study. Tibial transverse osteotomies were performed in both animals followed by external skeletal fixation. The medullary canals, which have already been prepared by removing the marrow through proximal and distal drill holes, were then injected with calcium phosphate cement (CPC). The outcomes were evaluated postoperatively by standard survey radiographs, morphology, histology and biomechanical testings. Healing processes appeared uncomplicated until week four where one bone fracture recurred due to external fixator failure. The results showed 56% and 48% cortical thickening, compared to the opposite site, in the fracture site and proximal and distal diaphyses respectively. This bone augmentative effect resulted in 264% increase in bending strength of the fracture site and 148% increase of the same value in the adjacent areas of diaphyses. In conclusion, IMCO, using CPC in tibia of sheep, is safe and biocompatible with bone physiology and healing. It possibly can carry the osteopromotive effect of the CPCs to provide a sustained source of bone augmentation throughout the diaphysis. Although the results must be considered preliminary, this method has possible advantages over conventional methods of bone fixation at least in bones with compromised quality (i.e. osteoporosis and bone cysts), where rigid metal implants may jeopardize eggshell cortices.
The use of bone grafts in treating non- or delayed unions as the result of large bone loss is well established. However, despite good outcomes, the time to achieve complete union is still considerably long. To overcome this problem, the use of platelet-rich plasma (PRP) has been advocated albeit with varying success. To determine the true effectiveness of PRP in treating non-/delayed unions, a study was conducted using (n=12) rabbit models.
We studied the factors influencing the mid-term outcomes of tibial plateau fractures treated conservatively (n=21) and surgically (n=27) from December 1994 to December 1997. Joint stability was an important prognostic determinant. In the surgical group, the most important factor was good anatomical reduction. Functional outcomes were comparable between the conservative and surgical groups. We concluded that conservative treatment is a valid option for fractures with minimal displacement and surgical treatment is justified for severely displaced or depressed fractures. Attention must be paid to the recognition and restoration of joint stability and articular surface congruency for a satisfactory outcome.
Sixty percent of open fracture wounds are contaminated at the time of injury. Despite that, the necessity for sequential multiple cultures and sensitivity studies for open fractures and their interpretation are still controversial. Predebridement, intraoperative, postoperative swabs and swabs in established infection for culture and sensitivity study were taken in 33 open tibial fractures over a 6 months period. 39.3% of predebridement swabs grew bacteria with the majority yielding gram-positive organism. None of the patients developed infection with similar organisms. 24.2% of the postoperative swabs grew bacteria, of which 75% were gram-negative. 50% of the patients with positive postoperative swabs developed infection. Thus, the role of sequential multiple cultures and sensitivity studies are not helpful in management of open fracture.
The results of treatment using a locally-designed external fixator in 20 patients are presented. Open fractures were the main indications for external fixation. Pin tract infection occurred in 8 patients. Only 2 patients had unstable fixation which required removal of the device. One third of patients developed malunion exceeding 15 degrees and two thirds had joint stiffness after conversion to plaster cast. This external fixator is adequate in the treatment of most open fractures of the tibia. However, improved techniques of pin insertion and cast application upon removal of the external fixator may help to reduce the incidence of pin tract infections and malunion.
Bone allografts donated by other individuals offer a viable alternative to autograft. Risks of disease transmission are overcome by sterilizing the bone; unfortunately sterilization methods generally affect bone functional properties including osteogenic potential and biomechanical integrity. This study aimed to determine any enhancement effect when gamma sterilised allografts was impregnated with autologous bone marrow in improving the rate and quality of integration in metaphyseal-tibial defects of rabbits. Almost all subjects showed 50% of the defect being covered by new bones by the third week and smaller residual defect size in the treated group at the fifth week. Hounsfield units at the defect site showed increasing healing in all samples, with the treated group having an apparent advantage although insignificant (p > 0.05). In the histopathological score evaluating healing over cortical and cancellous bone at the fracture site showed only slight variations between the groups (p > 0.05). Therefore no enhanced healing by the autologous bone marrow was observed when added to the bone allografts in treating the unicortical defects.