Orthopaedic Surgery/Fractures and Dislocations:Principles of Fractures
|Principles of Fractures|
"The question for the modern surgeon is not whether operative treatment is to supersede manipulative...The problem before each of us is how we can improve our skill and technique in both manipulative and operative treatment and what means must we adopt in each individual case to give our patients the surest, safest and most complete restoration of function." -Robert Jones 1913
This point of view recognizes two modes of fracture healing enchondral and intra-membranous. Closed management will attempt to optimize the former in which genetic expression at the fracture site will reiterate embryologic processes beginning with differentiation of recruited stem cells into cartilage cells. Open treatment will tend toward a direct differentiation to bone formation. Thus our treatments surgical or closed will either promote or interfere with these intrinsic mechanisms by which bone is capable of healing in an efficient scar free way so as to recreate its initial structure.
When the stucture of the bone is violently disrupted there is physical disruption of the matrix as well as the cellular elements of bone. Hemorrhage from disrupted blood vessels results in a fracture hematoma. We interpret what appears to be happening at a cellular level as an initial call for help, setting the stage for damage control and the recruiting of all available healing resources. There is pain which alerts us to the injury, there is swelling which splints the part and allows for the ready transit of any needed raw material out of the vasculature and into the zone of injury. Inflammation is the name we give to this first of three recognized phases of fracture healing.The first responders then generate messages in the form of chemotactic factors to call upon what is needed for the healing process to continue. This first 5 to 7days transitions into a process of cleaning out the damaged material, there is resorbtion of calcified bone, macrophage activation and modulation of mesenchymal pluripotential cells into fibroblasts and chondroblasts and osteoblasts, these activities dominate the picture from days 4 to 40 in what is known as the reparative phase. The process is accelerated in the young so that the reparative phase may be contracted into the first week in the new born and the final phase of fracture healing begins, the hallmark being the formation of calcified salts to form woven bone and radiographically aparent fracture healing. This is typically evident at 4 weeks, more so in diaphyseal bones especially those with a generous surround of muscle. Metaphyseal areas, intra-articular fractures, carpal bones and phalanges find a less exuberant or at least more delayed radiographic appearance even in the face of effective clinical union. This last phase known as the remodeling phase continues for a year or more.
A variety of endogenous and exogenous factors influence each of the three phases of fracture healing. The most important of these to recognize is the fact that a living patient is required to heal a fracture. The first implication of this fact is that attention must first be paid to the ABC's of resuscitation prior to attending to the dramatically flailed extremity which may attract attention while an insidious life threatening situation may be overlooked. The next consideration is that the bone will need blood supply to heal so will the soft tissues around the bone which may be precariously tented. Any deformity which is compromising the local perfusion about the fracture or to the distal extremity should be corrected. A survey of all areas presuming unrecognized secondary skeletal injury, and using the best available means, which is a laying on of hands to feel for crepitation and in the conscious patient to elicit tenderness will tend to yield an overlooked fracture in 15% of cases. In the case of high energy injury especially a fall from a height or a motor vehicular accident a skeletal survey to include spine and pelvis is usually pursued and commonly augmented by CT scan as this is generally used to screen for any intra-cranial or intra-abdominal injury is such cases thus a scan of the neck is easily added to supplement a cross table lateral plain film. The identified fractures should be xrayed with two views in the standard frontal and saggital planes if possible with the joint above and below the fracture site demonstrated.
The next priority is to address the open fracture with the goal of eliminating any foreign and devitalized material. The foreign material is considered to harbor micoorganisms which must be diminished in their quantity if not eliminated as they have an agenda entirely at odds with our purposes and will tend to thrive unchecked in the nutrient rich setting of a fracture. It is recognized that despite the most assiduous and repeated efforts in this regard some micoorganisms may persist at the fracture site, but if there are no sizable areas of devitalized tissue to harbor them then the patient's immune system in conjunction with parenterally administered antibiotics will eliminate any residual invaders. Due attention to the volume of irrigation in proportion to the area of injury, with formal surgical exposure of the intramedullary aspect of the bone is the goal, paying all due respect to the preservation of blood supply to the fracture and the overlying soft tissues. Pulse lavage and the use of a bone currette facilitates the process. It is instructive to inspect a freshly irrigated open tibia under loupe magnification to recognize that even after 10 liters of pulse lavage and scraping there remains low level contamination. Despite the best efforts some open fractures will become infected and usually from the proliferation of an organism that entered at the time of injury. Antibiotic resistence extent now in many communities requires surveillance to determine the optimal choice for initial antibiotic prophylaxis.
The desire to get on with what may be a lengthy process of stablizing the fracture with surgical implants must not be allowed to give short shrift to the process of cleansing the fracture site. From the point of view of an invading micoorganism, there is no more welcome addition than a large metallic surface allowing the organism the opportunity to form a defensive perimeter in the form of a membrane adjacent to the implant within which the organism will evade the patients immune mechanisms and the deadly effects of any antibiotics administered either parenterally or locally.
The desirability of stabilizing all long bone fractures as soon as possible must be tempered by a realistic appaisal of the level of resources immediately available, the level of fatigue and expertise of the surgical team, and the duration of anesthesia which may represent an undesirable level of immediate physiologic stress to a recently traumatized patient. If the crew is worn out, if the young surgeon is not quite sure of the best approach to stabilization, then focus on washing the fracture out and providing provisional stabilization allowing for a respite, reconsideration of options, and additional consultation, and availablity of the most appropriate implants for the purpose at hand. Many bad starts to a healing process are born in the middle of the night when strenuous efforts are brought to bear with the best of intensions.