Plates have been used from very early times to fix the bones internally. The plates serve to maintain length, rotation, and angulation at the fracture. Initially, there were Sherman plates, which used self-tapping screws. Then came the Broad, Narrow and Small plates of A O type. They were used with compression devices to give a rigid internal fixation. There used to be cortex to cortex union with no visible callus formation. To achieve an anatomical reduction extensive dissection was done. The periosteum was stripped mercilessly. At that time the biological treatment concept was not there. The heavy plates were tightened to fix on the bone. The area under the plate lost its periosteal blood supply and became avascular. The stability was produces by the friction between the undersurface of plate and bone. The avascular bone corroded and the holes in bones for screws got osteonecrosed and loose hence they failed to hold till union quite often.
There was incidence of sterile sequestrum formation in the avascular bone. The process of fracture union used to get delayed till they were revascularized by creeping substitution. Till then the limb had to be immobilized causing stiffness, weakness, muscle atrophy, joint stiffness (fracture disease).
Next came Dynamic Compression plates (DCP). Which due to its special hole pattern produced compression without compression device and concept of extra-periosteal plate came. Still, there was avascular area under the plate. Which was further reduced by Low Contact Dynamic Compression Plate (LCDCP). Here the avascular area under the plate was less. Care was taken to avoid unnecessary periosteal stripping. Hence the union was quicker and better.
With these principles in mind, the DCP and LCDCP reduced the fracture healing time and there was some callus formation. There was consequent early mobilization and less amount of Fracture disease.
Once the true nature of these events was uncovered, the priorities changed from mechanical stability to biology. The biological internal fixation or bio-buttress fixation is one that makes sense from the biological point of view. Blind, subcutaneous, or submuscular insertion of an implant like a bone plate via a minimal surgical approach to preserve vascularity and fixing it by the newer aiming and stabilizing technologies to achieve elastic flexible fixation is part of this protocol. It took some more time to come with the concept of the internal fixator.
The healing pattern of bone is more natural with visible callus formation, and its strength returns early since live bone heals in a shorter time than creeping substitution of dead bone. The locked internal fixation plates! (LIFE) represents a novel, bio-friendly approach to internal fixation. It resembles a plate, but its biological and mechanical characteristics are different and it functions rather like a fully implanted external fixator, even in its healing pattern. It is known that external fixator causes least vascular damage in comparison to intramedullary nailing or conventional plate fixation.
This is the L C P. These plates were custom made for different parts of bones and areas. They were made to tackle even the periarticular fractures. These plates were also slotted in the undersurface to reduce the amount of periosteal damage. The holes had an option of fixation with two types of screws. The first one was a regular cortical or cancellous screw which fixed the plate to the bone in the desired position, the other was a locking option. They have a guide to fix the direction of the screws to the plate. The holes are having threads as well as on the screw heads so that on tightening the screws it fixed to the plate without producing unnecessary compression of the plate on the bone. The healing pattern of bone is more natural with visible callus formation, and its strength returns early since live bone heals in shorter time than creeping substitution of dead bone. The locked internal fixation plates (LIFE) represents a novel, bio-friendly approach to internal fixation. It resembles a plate, but its biological and mechanical characteristics are different and it functions rather like a fully implanted external fixator, even in its healing pattern. I am known that external fixator causes least vascular damage in Comparison to intramedullary nailing or conventional plate fixation.
Spinal or spine implant systems made of titanium and other materials, utilizing specially designed spinal instrumentation are often used when spinal conditions require surgery. The implants facilitate fusion, correct deformities, and stabilize and strengthen the spine.
Conditions that often require instrumented fusion surgery include slippage of the spine (spondylolisthesis), chronic degenerative disc disease, traumatic fracture, and other painful forms of spinal instability including scoliosis.
Implants for Spine Surgery are made of metals like titanium, titanium-alloy or stainless steel; some are made of non-metallic compounds. These are available in different shapes and sizes to accommodate patients of all gender and ages.
Scientists and surgeons around the world are constantly working to develop and refine implants. In recent years there have been huge advances, including the advent of a hook, rod and screw systems that enable surgeons to correct spinal deformities 3-dimensionally; the development of special plates and cages that help promote spinal fusion; and the creation of small but strong implants for children.
Type of Spine Implants
- Rods–Rods are used, along with hooks and screws, to immobilize involved spinal levels, and to contour the spine into correct alignment. One of the original implants used in the spine, the rods are strong, yet have some flexibility so that the surgeon can shape the rod to match the contours of the patient’s spine.
- Pedicle Screws– Deriving its name from pedicles of the spinal vertebrae, these specially designed screws are carefully implanted into the pedicles. Traditionally used in the lumbar spine, with recent advances in technology and technique, surgeons are now using them in the thoracic spine too. Screws provide strong “anchorage” points to which rods can be attached. Rods can then be contoured to correct deformities and to facilitate fusion.
- Hooks– These are used with rods and other implants to anchor them to vertebrae.
- Plates– Plates are mostly used in the cervical spine. Plates are manufactured to conform to the contour of the spine and are held in place by screws set into adjacent vertebrae. When the plate requires adjustment, a contouring tool is used to customize the fit to the patient’s anatomy.
- Cages– These are most often placed between two vertebrae and are called “interbody” cages. Cages are small hollow devices with perforated walls. Bone graft or BMP is often packed into the cage to promote bone growth between the adjacent vertebrae. Cages are used to restore lost disc height resulting from a collapsed disc and to relieve pressure on nerve roots.
Application of Spine Implants
Implants are carefully chosen to ensure the best choice for the specific patient. For example, “low volume” implants are used because they reduce muscle irritation and cause less post-operative pain. For patients who are slim, “low profile” implants not visible through the skin are used. Titanium is preferred material as it is strong, light and, unlike stainless steel implants, can be used with MRIs. When suitable, use of radiolucent materials such as carbon fiber cages is also followed. Carbon-fiber implants cannot be seen on a scan but allow us to see if a bone is forming and fusion is taking place.
Future of Spine or Spinal Implants
Scientists are working on developing bio-resorbable implants. These are used to facilitate fusion. However, after a year or so (when fusion should be complete) the implant is not necessary but is left in the body. Bio-resorbable implants are designed to break down when they come in to contact with water (such as body fluids). In a year, most decreases in size by 50% and are completely gone in 2-3 years. Thus the implant is present in the body when it is needed to promote fusion, and then gradually “fades-away” over a 12-36 month period. Though only a few bio-resorbable implants are available, it is hoped that in future a significant step in this field would take place.
In the past two decades, there have been major breakthroughs in the development of spinal implants. The result is a better treatment option for patients.
A bone, if fractured needs to be properly aligned and stabilized so that it unites and is strong enough to handle the body’s weight and movement. Earlier, Doctors relied on casts and splints from outside the body to support and stabilize the bone. The development of a surgical intervention to internally set and stabilize fractured bones using Implants is now widely practiced.
To treat a fracture, the bone fragments are first repositioned (reduced) into their normal alignment during the surgical procedure. Special implants Viz. plates, screws, nails, and wires hold them together.
Some of the advantages of such Internal fixation procedure are:
- shorter hospital stays,
- enables patients to return to his normal function faster, and
- reduces the incidence of nonunion (improper healing) and malunion (healing in improper position) of fractured bones.
The implants are made from stainless steel and titanium, which are durable and strong. In the case of joint replacement, these implants can also be made of cobalt and chrome alloy. The Implant material is compatible with the body and rarely cause an allergic reaction.
Most often used an implant for internal fixation is Screws. Although it is a simple device, there are various designs depending upon the type of fracture and place of use. Screws different sizes are used with bones of varying sizes. Screws may be used alone to hold a fracture and is used with plates, rods, or nails. After the bone unites, screws may be either left in place or removed.
Plates hold the broken pieces of bone together and work as an internal splint. Screws are used to fix it to the bone. After healing of the bone is complete, Plates may be left in place or may be removed.
Nails or Rods
Long bones in our body are hollow at its center. Inserting a rod or nail through the hollow center of the bone to hold the bone pieces together is adopted the technique in some fractures of the long bones. Screws at each end of the rod are used to keep the fracture from shortening or rotating and hold the rod in place until the fracture has healed. Rods and screws may be removed after healing is complete or left in the bone. This technique is commonly used to treat the fractures in the femur (thighbone) and tibia (shinbone) bone.
Wires are often used to pin the bones back together. They are often used to hold together pieces of bone that are too small to be fixed with screws. In many cases, they are used in conjunction with other forms of internal fixation, but they can be used alone to treat fractures of small bones, such as those found in the hand or foot. Wires are usually removed after a certain amount of time but maybe left in permanently for some fractures.
External fixation is often used to hold the bones together temporarily when the skin and muscles have been injured. An external fixator acts as a stabilizing frame to hold the broken bones in the proper position. In an external fixator, metal pins or screws are placed into the bone through small incisions into the skin and muscle. The pins and screws are attached to a frame outside the skin. Because pins are inserted into the bone, external fixators differ from casts and splints which rely solely on external support.
In many cases, external fixation is used as a temporary treatment for fractures. Because they are easily applied, external fixators are often put on when a patient has multiple injuries and is not yet ready for a longer surgery to fix the fracture. An external fixator provides good, temporary stability until the patient is healthy enough for the final surgery.
Other times, an external fixator can be used as the device to stabilize the bone until healing is complete.
There may be some inflammation or, less commonly, infection associated with the use of external fixators. This is typically managed with wound care and/or oral antibiotics.
Sterile conditions and advances in surgical techniques reduce but do not remove, the risk of infection when internal fixation is used. The severity of the fracture, its location, and the medical status of the patient must all be considered.
In addition, no technique is foolproof. The fracture may not heal properly or the plate or rod may break or deform. Although some media attention has focused on the possibility that cancer could develop near a long-term implant, there is little evidence documenting an actual cancer risk and much evidence against that possibility. Orthopaedic surgeons are continuing their research to develop improved methods for treating fractures.
The humerus bone connects the shoulder to the elbow. The upper extremity includes this segment of the body together with the hand and the forearm. The humerus is a strong bone which has the ball of the ball-and-socket shoulder joint on the top and a hinge of the elbow joint on the bottom. There are three types of humerus fractures: proximal humerus fractures of the shoulder, mid-shaft humerus fractures, and distal humerus fractures of the elbow.
Mid-Shaft Humerus Fractures
A mid-shaft humerus fracture does not involve the shoulder or elbow joints. Statistically, about 3% of all broken bones constitute this type of fracture. The most common reason of a humeral shaft fracture is a fall or high-energy injuries (motor vehicle collisions, sports injuries). Penetrating trauma (gunshot wounds) can also cause this injury. Osteoporosis is known to be a cause for many humeral shaft fractures.
The X-rays often frighten the patients, because there is only one bone connecting the shoulder to the elbow, and patients fear as though their arm is not attached. However, they should be reassured, that there is much more than bone that holds the arm and that the vast majority of mid-shaft humerus fractures heal without surgery.
Non-surgical treatments are the most common treatment options. Thanks to gravity, which works to align the humerus, and often the best treatment for a humerus fracture is simply allowing the arm to hang by the side. Furthermore, minimizing the chance of
complication is one reason to consider non-surgical treatment.
Multiple fractures, open fractures, injuries to blood vessels or nerves, and failure of healing with nonsurgical treatment (nonunion) lead to surgical treatment, which includes.
- Fracture Bracing: Fracture brace, often referred to as a Sarmiento brace, named after the physician who popularized this treatment is the most common treatment for a humeral shaft fracture. Usually, the fracture is treated with a splint or sling allowing swelling to subside, and then a fracture brace is fitted to the patient. The brace holds the humerus in alignment and looks like a clamshell. As healing progresses, patients can begin to use their shoulder and elbow.
- Metal Plates: The most common surgical treatment of a humerus fracture is to place a large metal locking plate along the humerus and secure it with screws. In comparison to non-surgical treatments, surgical treatments have higher associated risks of nerve injury and nonunion.
- Rods: An intramedullary metallic rod is placed in the hollow center of the bone. The advantages of this option is that the surgery is less invasive, and the surgeon is working far from the important nerves that travel down the arm. The concern with a rod is that healing rates are not high, and nonunion is a common problem.
Healing Time and Complications
Though complete healing of a mid-shaft humerus fracture takes several months, exercises to improve the mobility of the shoulder and elbow joints may be initiated much sooner. The two complications usually encountered are injuries to the radial nerve and nonunion of the fracture.
Radial nerve tightly wraps around the middle of the humerus and injuries to it may occur. It may be injured at the time of the fracture or during treatment. Radial nerve injuries cause numbness on the back of the hand, and difficulty straightening (extending) the wrist and fingers. Most radial nerve injuries improve with time, but the doctor needs to follow this carefully to decide any further treatment.
Nonunion is when the fracture does not heal. Several reasons could result in a nonunion. One of the most common reasons for nonunion is surgery. The soft tissues surrounding the fracture are further disrupted by surgery and this can compromise blood flow to the site of the fracture. While, it would be advisable to avoid surgery to prevent the risk of nonunion, but in case of a nonunion surgery is almost always needed to stimulate a healing response of the bone.
Preoperative planning has always been a significant component of the complete strategy of fracture care by surgical intervention.
Preoperative planning enables the surgeon to perform the operation in his mind prior to the actual surgical procedure. It gives him an opportunity to prepare the equipment that might be needed and allows him to plan the steps of the operation, including the location of the incisions, choice of trauma implants, reduction technique and techniques of application.
With preoperative planning the orthopedic surgeon is better prepared for surgery, therefore ensuring a higher chance of success as well as avoiding possible complications. Another benefit is that the surgeon may provide the patient with a detailed explanation of the operation so that he may obtain informed consent and forge a good patient-surgeon relationship.
Planning in MIPO
In MIPO, preoperative planning plays an even more important role. Since the fracture sites aren’t visualized or exposed, the surgeon must plan each step of the surgical procedure to make sure that the operation proceeds smoothly, precious time isn’t wasted, and that unnecessary exposure to irradiation is prevented.
The following guidelines can be helpful in the decision-making process as well as the preparation of a preoperative plan for MIPO.
Appropriate assessment of the patient and the injury is essential for correct decision making. This includes a detailed history, relevant laboratory tests, a careful physical examination, x-rays, and other ancillary imaging studies if specified.
Patient factors that need to be considered in the decision-making process include:
- Post-trauma status including hemodynamic stability
- Future expectations
- Patient compliance
- General medical status and comorbidities
- Quality of bone
- Preinjury functional status
- Patient compliance
- Future expectations
This evaluation aids to decide whether the patient is an appropriate candidate for surgery and is fit for anesthesia.
For proper assessment of the fracture, good quality x-rays are essential. Traction films are beneficial in some instances. Other imaging studies that can be helpful include CT scans, MRI, 3-D reconstructions, and vascular studies.
The fracture factors that should be taken into consideration include:
- Duration after injury
- Closed open fracture
- Simple, wedge or complex
- Associated fractures
- Location- articular, metaphyseal or diaphyseal
- Condition of the skin and soft tissues
- Neurovascular injuries
- Associated injuries
Good indications for MIPO are complex or multifragmentary fractures of the metaphysis and diaphysis and fractures of intraarticular with extension into the diaphysis.
Relative indications are simple diaphyseal fractures and some open fractures.
Graphic preoperative plan
One of the necessities of a good preoperative plan is to make a graphic representation of the fracture fragments, manipulating the fragments on paper to attain a reduction, selecting the suitable orthopedic implants and superimposing them on the reduced fracture utilizing templates, and reviewing the plan to see whether the desired result is attained.
To prepare the preoperative plan, the following are important:
- X-rays of good quality, including views of the normal side if possible
- Tracing paper (or transparencies)
- Colored felt-tipped pens and pencils
- Additional imaging such as CT scans (especially for intra-articular fractures)
- Relevant implant templates of the correct scale
- A goniometer
The following planning techniques are usually used.
- Direct overlay
- Use of the physiological axes for articular fractures
- Overlay using the normal side
Distal Femur is the part of thighbone above Knee joint, which pans out like an inverted funnel. A fracture in this bone is termed a Distal Femur Fracture.
Such fractures commonly occur in people whose bones are weak due to old age, or in younger people who have suffered high energy injuries like a car crash. In both, the elderly and the young, the injury may extend into the knee joint and may shatter the bone into many pieces.
The largest weight-bearing joint in the body is the Knee. While distal femur bone makes up the top part of the knee, the upper part of Tibia bone supports the bottom part of the knee joint.
Articular cartilage, a smooth, slippery substance covers the ends of the femur. When we bend or straighten our knee, this cartilage protects and cushions the bone.
Normal knee anatomy
Knee Joint is supported by strong muscles. Muscle in the front of our thigh is called Quadriceps, while the one at the back of thigh is Hamstrings. Apart from supporting, they also allow us to bend and straighten our knee.
There are different types of Distal Femur Fractures. The bone may break in transverse plane or into many pieces (comminuted fracture). Sometimes the fracture may extend into the knee joint and separate the surface of the bone into a few (or many) parts. Such fractures are called intra-articular. Due to damage to the cartilage surface of the bone, intra-articular fractures can be more difficult to treat.
Various fracture types of distal femur:
(Left) A transverse fracture across the distal femur.
(Center) An intra-articular fracture that extends into the knee joint.
(Right) A comminuted fracture that extends into the knee joint and upwards into the femoral shaft.
Distal femur fractures can be closed — if the skin is intact — or can be open. An open fracture is when a bone breaks in such a way that bone fragments stick out through the skin or a wound penetrates down to the broken bone.
Open fractures often have associated damage to the surrounding muscles, tendons, and ligaments. Thus, they have a higher risk of complications and take a longer time to heal.
The hamstrings and quadriceps muscles, both tend to contract and shorten when the distal femur breaks. In such case, the bone fragments change position and it is difficult to line up with a cast.
Distal femur fracture in which the bones are out of alignment
In this x-ray of the knee taken from the side, the muscles at the front and back of the thigh have shortened and pulled the broken pieces of bone out of alignment.
As discussed earlier, Fractures of distal femur occur mostly in younger people (under age 50) or the elderly.
Younger patients suffer high energy injuries usually caused by falls from significant heights or motor vehicle collisions. Due to the high energy impact, many patients also often have injuries of the head, chest, abdomen, pelvis, spine, and other limbs.
In Elderly people, with age the bone quality becomes poor. Bone become thinner and become very weak and fragile. A lower-force impact, like a fall from standing, can also cause a distal femur fracture. Although elderly patients do not often have other injuries, they may have concerning medical problems, such as conditions of the heart, lungs, and kidneys, and diabetes.
The most common symptoms of distal femur fracture include:
Pain with weight-bearing
Swelling and bruising
Tenderness to touch
Deformity — the knee may look “out of place” and the leg may appear shorter and crooked
While in majority of cases, these symptoms occur around the knee, but there may also be symptoms in the thigh area.
The following are some general guidelines when using these implants for Locking compression plate-LCP
- Whenever possible, the fracture is first reduced by indirect means.
- If required, the reduction is then maintained using external fixators or distractors.
- If a well-contoured or anatomically preshaped plate is utilized, the implant may be used as a reduction aid when utilized with standard screws.
- If the compression purpose of the LCP is to be utilized, for example in simple transverse fractures, correct contouring of the plate is first performed; axial compression may then be carried out utilizing standard screws in the dynamic compression unit of the combination holes. It’s significant to note that the LCP combination holes are arranged asymmetrically on the plate. This asymmetry enables axial dynamic compression to be exerted unidirectionally. After exerting axial compression by the standard screws, further LHS may then be inserted.
- If it’s desired to apply interfragmentary compression in spiral or simple oblique fractures, this should first be accomplished utilizing standard screws as lag screws prior the application of LHS.
- To insert standard screws, the universal drill guide is utilized. The screw holes are predrilled, either eccentrically or neutrally, depending on the screw’s intended function. The depth of the screw hole is then measured as well as tapped, and the suitable standard screw inserted.
- If plate contouring is required, it should be performed using the suitable bending instruments. Bending should be done between the combination holes and not done through the holes as this can cause deformation of the holes and lead to difficulty in the following insertion of LHS. One way of preventing this deformation is to insert an LHS or a threaded drill sleeve into the threaded portion of the combination hole before carrying out the bending.
- If wanted, an LCP spacer be screwed into the plate before its insertion. The spacer ensures a gap of 2 mm between the plate and underlying cortex, therefore minimizing plate-bone contact and preserving periosteal circulation. This spacer may be removed after insertion of the LHS.
- Skin incisions are made, corresponding in location to the ends of the plate.
- A tunneler can be used to create a submuscular extra-periosteal tunnel for the bone plate.
- The bone plate is then passed into the tunnel. This may be done in one of many ways. If a tunneler is utilized, one end of the plate is tied with a suture to the end of the tunneler. As the tunneler is withdrawn, the bone plate is pulled into position. Another way is to fix plate’s one end with a plate holder or a threaded LCP drill guide which is then utilized to guide the plate into position along the track made by the tunneler.
- Once the plate is in place, bone screw insertion may follow. If the first inserted bone screw is an LHS, before locking, the other end of the plate should be temporarily stabilized with either a standard screw, a K-wire, a threaded LCP drill guide, or another LHS that isn’t locked. This is to avoid the plate from rotating and causing damage to the surrounding soft tissue as the 1st LHS is tightened and locked.
- If the equally of fracture reduction satisfactory, the rest of the LHS are inserted.
- To insert a self-tapping LHS percutaneously, a threaded LCP drill guide is 1st introduced through a stab incision in the skin, and then screwed into the threaded part of the selected combination hole. The drill guide makes sure that drilling is done in the accurate direction so that the screw is appropriately locked to attain maximal angular stability. The screw hole is then drilled and measured, and the suitable LHS inserted, first utilizing a power tool with the screwdriver shaft and then performing the final tightening by hand with the torque-limiting until clicking happens.
- Predrilling and depth measurement aren’t essential if a self-drilling, self-tapping LHS is used monocortically. This, though, is only possible in good-quality bone with a thick cortex. Monocortical screw fixation is also specified in periprosthetic fractures.
There are two bones in the forearm – radius and the ulna. When one or both the bones of the forearm have a fracture, we term it as Forearm Fracture. Both bones are important not only for proper motion of the elbow and wrist joints but also serve as important attachments to muscles of the upper extremity.
A most common reason for fractures is due to a fall on the hand, or a direct blow to the forearm (commonly seen in altercations, sports injuries, and car accidents). Pain, swelling, and deformity of the forearm indicate a forearm fracture. Proper diagnosis can be made with physical examination and x-ray studies.
Radial shaft fractures, ulnar shaft fractures, and fractures of both forearm bones are discussed below. Siora Surgicals has manufacture locking implants for hand fracture. Other Fractures that occur around the elbow (radial head fractures and olecranon fractures) and those that occur around the wrist (wrist fractures), will be covered separately.
Radial Shaft Fractures
It is not common to suffer an isolated fracture of the radial shaft. Most fractures of the radial shaft are associated with injury to the ulna (see ‘both bones forearm fracture’ below) or injury to one of the joints around the wrist (Galeazzi fracture).
An isolated radial shaft fracture, if it occurs, commonly requires surgery unless the fracture is non-displaced. If the fracture is out of position, then fracture is realigned to allow forearm rotation. Hence, surgery is the preferred treatment option to realign and hold the bones in the proper position.
Ulnar Shaft Fractures
An isolated fracture to the ulna is most often caused during an altercation and is called a “nightstick” fracture. Raising of the forearm in a protective posture exposes the ulna bone, which can be damaged by a blunt traumatic hit. The name is derived from the defensive gesture of people trying to shield themselves from a policeman’s nightstick leading to ulnar fractures.
If the fracture is well aligned, an isolated ulna fracture can be treated with immobilization in a cast. However, if the fracture is badly displaced, or the skin is broken causing an open fracture, then surgical treatment is advised.
Both Bones Forearm Fracture
Fracture of Both bones almost always require surgery in an adult patient. Without surgery, the forearm is generally unstable and to cast this type of fracture in a proper orientation is very difficult if possible. In younger children, nonsurgical treatment can be considered, but in adolescents, surgery may have to be carried out.
Fractures of both bones of the forearm are most commonly treated by fixing a metal plate and screws on both the radius and ulna bones. These bones have to be approached through a separate incision, necessitating, therefore, you will have two incisions on your forearm. Some surgeons may use a rod within the bone to maintain the position of the bone, but this cannot be done in fractures where rotational stability is required. Hence, both bones forearm fractures are mostly treated with plate and screws.
Complications of Forearm Fractures
The complications that are commonly encountered in such fractures include:
- Limited Motion: After the treatment of forearm fractures, decreased motion capability is common. It can be limited in the elbow and wrist joints but is most commonly noticed in forearm rotation (i.e. opening a jar or turning a door handle).
- Non-Healing Fracture: Due to inadequate healing of the bones of the forearm, there may be persistent pain. In open Fractures or where the bone is lost (i.e. many small pieces), this problem is more likely to occur. In such cases, repeat surgery for bone grafting may be necessary.
- Infection: Post-surgery, possibility of Infection is common. An infection in forearm fracture after surgery may require removal of the metal plate and screws to cure the infection.
Painful Hardware: Many times, the metal implants used during surgery can be felt under the skin and are painful. They can be removed, after the bone has properly united, usually at least a year after surgery.
The overview of the internal fixator has made MIPO a more practical theory and expanded its scope and range of applications.
The internal fixator is a submuscular or subcutaneously positioned external fixator. The design feature that is unique of the internal fixator is the locking head screw (LHS)- the screw head incorporates a double conical thread for safe fixation into a corresponding conical thread in the hole of the plate. This characteristic imparts a degree of angular stability to the construct because the locked screw head can no longer toggle within the plate hole. Also, because the screw head is secured within the plate hole, it doesn’t press the plate against the underlying bone as the screw is tightened, in contrast to standard screws such as cancellous or cortex bone screws.
The internal fixator, therefore, possesses characteristics that make it suitable for MIPO. These include:
- LHS which prevent the bone plate from being pressed against the underlying bone, therefore sparing the periosteal blood supply.
- Since the bone isn’t pulled against the plate by the LHS because the bone screws are tightened, there is no loss of primary reduction if the fracture has previously been reduced.
- Consequently, correct contouring of the plate isn’t necessary, a definite benefit in MIPO as the bone isn’t exposed for templating.
- Angular stability of the construct also avoids secondary loss of fracture’s reduction when placed under load.
- As the LHS are either self-tapping and self-drilling or only self-tapping, application of screw is made easier in the MIPO setting as drilling and/or tapping is no longer needed as is the situation with the application of standard screws.
The 1st internal fixator specifically intended for use in MIPO was the less invasive stabilization system (LISS) for the distal femur. As the benefits of the LISS became apparent, demand for a more versatile system risen, and this result in the development of the locking compression plate (LCP) with a specially intended combination hole, one half of which is intended as a dynamic compression until that enables the use of standard screws for interfragmentary or axial compression, while the other half is threaded to enable the application of LHS. Therefore, the LCP may function as a compression plate or as an internal fixator when only LHS are utilized.
In theory, no contouring of the LCP is essential when used as an internal fixator, however in practice, some degree of contouring is usually required, especially in the bone’s epi-metaphyseal segments. Otherwise, the plate can stand proud and become prominent subcutaneously or cause irritation of the adjacent soft tissue. To overcome this issue, specially intended metaphyseal plates were introduced. The special characteristics of this plate are that the juxta-articular end of the plate is thinned out to aid contouring and the two distal holes in this thinned part of the plate are angled at 11⁰ toward the center of the plate to enable optimal application of the LHS in the epiphyseal part in order to avoid penetration of the articular surface. A further refinement of this is the progress of anatomically preshaped LCP for use in specific epi-metaphyseal portions of the skeleton. The metaphyseal end of such a plate enables the insertion of a cluster of LHS in a convergent or divergent manner to improve their pull-strength. Additionally, no contouring of the plate is usually required. An added benefit of this anatomical preshaped LCP is that they may be used as an aid for indirect fracture reduction when utilized with standard screws. These may draw the bone toward the plate and therefore effect an adaptation of the bony fragments to the shape of the bone plate. Examples of anatomically preshaped LCP are the LCP distal humerus, locking proximal humerus plate (LPHP), LCP distal radius, LCP distal femur, LCP distal tibia, and LCP proximal lateral tibia.