A post mortem study of fracture of Long Bones

Mechanical trauma of adequate force, whatever the nature of the agent, usually leads to a wound. The latter may be limited to the tissues covering the outer and inner surface of the body, namely skin and mucous membranes, giving rise to a superficial injury, or may involve as well one or more of the deeper structures like bone leading to fracture. Examination of an injury in both living and dead is an important medico-legal issue in the field of crime investigation to fix the liability. A doctor is required to date injuries specifically and individually while preparing an injury report. In all traumatic deaths where fractures were found over the body, it is important to find out whether these injuries were caused while alive and not after death of a person. The forensic pathologist can be confronted with the estimation of fracture age in association with murder, manslaughter, and bodily harm with fatal consequences, (primarily survived) accidents and further constellations. In this paper we have studied the sequential Gross and Histopathological Changes at the Site of Fracture injuries and compared the findings with available standard data. Total 78 Medicolegal deaths having long bone fractures over the body, brought for post-mortem examination, over a period of two year were studied.


Introduction
Mechanical trauma of adequate force, whatever the nature of the agent, usually leads to a wound. The latter may be limited to the tissues covering the outer and inner surface of the body, namely skin and mucous membranes, giving rise to a superficial injury, or may involve as well one or more of the deeper structures like bone leading to fracture. Fracture is a complete or incomplete break in the continuity of a bone. Although in most fractures, there is a distinct history of trauma. (1,2) Diagnosis of a Fracture 1 can nearly always be inferred from the history and clinical examination. However, clinical evidence must always be confirmed or refuted by radiological examination. Some fairly constant signs of fracture which should arouse suspicion include: (i) local swelling, (ii) local tenderness, (iii) visible or palpable deformity and (iv) impairment of function. Dating of an injury in both living and dead is an important medicolegal issue in the field of crime investigation to fix the liability. A doctor is required to date injuries specifically and individually while preparing an injury report.
In all traumatic deaths where fractures were found over the body, it is important to find out whether these injuries were caused while alive and not after death of a person. Fracture age describes the time interval between the infliction of a fracture of bone and the time of death, and in living person till time of examination. (1) It can be considered as the survival time of the individual following a physical injury. The forensic pathologist can be confronted with the estimation of fracture age in association with murder, manslaughter, and bodily harm with fatal consequences, (primarily survived) accidents and further constellations. A forensic expert must be able to distinguish vital reactions from agonal as well as supravital reactions and finally from post-mortem changes. While agonal changes can arise during a state of vita minima, changes are considered to represent a supravital reaction if they are expressed after circulatory arrest and may have the appearance of a vital reaction. (1) Dating of an injury both in the living and dead is an important medico legal problem in the field of investigation of crime. Moreover, all the injuries found on the body of a victim might not have been inflicted at the same time and even on the same day. Though it will not be possible to give exact time of infliction of injury, yet approximate age of the injury can be made out from the reparative changes that occur after infliction of any injury; reaction to injury is immediate, and it continues until the repair is complete. (2) The bone healing process is greatly influenced by a variety of systemic and local factors. A thorough understanding of the basic science of bone healing as well as the many factors that can affect it is highly critical to time it.
Objectives of the Study 1. To study Gross and Histo-pathological changes at the site of Fracture. 2. To study the time since infliction of Fracture Injuries. 3. To compare gross changes with histo-pathological changes at site of fracture in relation to time.

Material and Method
The study was carried out with an objective to study certain medico legal aspects of Fractures on the basis of its gross & histopathological examination at the time of post-mortem.

Discussion
The Healing of fractures is in many ways similar to the healing of soft-tissue wounds, except that the end result is mineralized mesenchymal tissue, i.e. bone. (3) A fracture begins to heal as soon as the bone is broken, and through a continuous series of stages. A continuously occurring state of bone deposition, resorption, and remodeling facilitates the healing process. The cellular components of bone consist of osteogenic precursor cells, osteoblasts, osteoclasts, osteocytes, and the hematopoietic elements of bone marrow. (4,5) Osteoblasts are mature, metabolically active, bone-forming cells. They secrete osteoid, the unmineralized organic matrix that subsequently undergoes mineralization, giving the bone its strength and rigidity. Osteoblasts also play a role in the activation of bone resorption by osteoclasts.
There are three primary types of bone: woven bone, cortical bone, and cancellous bone. (3,4) Woven bone is found during embryonic development, during fracture healing (callus formation). Woven bone is normally remodelled and replaced with cortical or cancellous bone. Osteoid is the unmineralized organic matrix secreted by osteoblasts. It is composed of 90% type I collagen and 10% ground substance, which consists of non-collagenous proteins, glycoproteins, proteoglycans, peptides, carbohydrates, and lipids. The mineralization of osteoid by inorganic mineral salt calcium phosphate provides bone with its strength and rigidity. (5,6) Healing occurs in overlapping stages of: 1) Stage of hematoma; 2) Stage of Inflammation & granulation tissue formation; 3) Stage of callus; 4) Stage of remodelling & modelling (Consolidation). (7,8,9) Stage of haematoma: This stage lasts for 7-10 days. When a bone is fractured, blood leaks out through torn vessels in the bone and forms a haematoma between and around the fracture. (10,11) Stage of Inflammation & granulation tissue formation : This stage lasts for about 2-4 weeks. In this stage, Inflammatory cells (macrophages, monocytes, lymphocytes, and polymorphonuclear cells) and fibroblasts infiltrate the bone under prostaglandin mediation. The sensitised precursor cells (daughter cells) produce cells which differentiate and organise to provide blood vessels, fibroblasts, osteoblasts etc. Collectively they form a soft granulation tissue in the space between the fracture fragments. Stage of callus (Woven bone) Formation: This stage lasts for about 4-12 weeks. In this stage, the granulation tissue differentiates further and creates osteoblasts. These cells lay down an intercellular matrix which soon becomes impregnated with calcium salts. This results in formulation of the callus, also called woven bone. The callus is the first sign of union visible on X-rays, usually 3 weeks after the fracture. Stage of remodeling & modelling (Consolidation): in this stage, the woven bone is replaced by mature bone with a typical lamellar structure. Adequate strength is typically achieved in 3 to 6 months. (8,12) In present study, death has occurred within 24 hours of infliction of fracture in 26 (33.33%) cases. Out of these 26 (33.33%) cases 19 (24.36%) were of simple fracture & 7 (8.97%) were of compound fracture. On  There is no similar study is available to compare our findings except literature on bone healing that mentioned in standard textbooks. It is not possible to determine exactly the age of an injury on the basis of its appearance to the naked eye. The results obtained are erroneous because of variability of the intensity of local inflammatory reaction. (1,3,7,12)

Limitation of Study
Factors affecting healing process are not studied in this study as all cases selected for this study are healthy individuals; this is one of the limitations of this study. Study of enzyme histochemistry of wound as documented in literature which is also one of the useful tool for age estimation of injury is not considered in this study which would have been additional source to arrive to more precise conclusions, is one of the limitation of the study.

Summary and Conclusion
Medico legal autopsy is an important part of an examination for scientific determination of age of Fracture. Careful gross examination study of fracture site can be helpful to arrive at conclusion about their antemortem or post-mortem nature in most of the cases. However in few cases, there are limitations to gross examination to conclude ante-mortem or post-mortem nature of fracture & to decide age of injury. Hisotpathological study to determine the age of injury is useful and advanced method which is helpful for investigation and proper administration of justice. Proper selection of tissue samples with proper preservatives and qualitative technology is necessary for perfect microscopic observation and conclusions. Histopathological examination is further helpful to give closer range of timing of infliction of fracture as compared to only gross examination. On histopathological examination of fractures of age of few hours revealed RBC's infiltration and delayed cases, callus and woven bone formation noted. Age of injury is important in disputed insurance settlement, road traffic accident claim, prisoners died in police custody and in homicidal deaths.