Osteosynthesis or metal osteosynthesis in bone fractures’ treatment
Metal osteosynthesis (MOS of fractures) is one of the fundamental methods to manage unstable long bone fractures and in many situations - the only remedy available (putting aside replacing a damaged joint). It enables correct healing in severe situations like intraarticular fractures with impairments of cartilage surface integrity, comminuted fractures with significant fragments' displacements and large bone defects.
Osteosynthesis or metal osteosynthesis in bone fractures’ treatment
What is osteosynthesis? What are the types of osteosynthesis? Indications and contraindications. Where to apply a specific method of osteosynthesis? Modern methods of osteosynthesis and looking to the future
What is osteosynthesis?
According to Wikipedia, Osteosynthesis (Anc. Greek ὀστέον – a bone; σύνθεσις — junction, connection) is a surgical reposition (matching) bone fragments for durable elimination of their mobility. Osteosynthesis ensures the reliable fixation of bone fragments in their correct position, preserves a segment's functional axis and stabilizes the fracture area till fusion completes. In turn, a more extended name – metal osteosynthesis (MOS) predetermines the use of fixing devices made of different metal alloys or combinations of metal and polymer. The materials are biologically, chemically, and physically inert and do not interact with the human body. Among materials, there are different kinds of steel, titanium alloys, their combinations with polymers or ceramics, as in the case of endoprostheses
Металоостеосинтез (МОС переломів) є одним з основних методів при лікуванні нестабільних переломів довгих трубчастих кісток, а часто єдино можливим (крім ендопротезування пошкодженого суглоба) особливо при внутрішньосуглобових переломах з порушенням цілісності суглобової поверхні, багатоуламкових переломах з великим зміщенням та великих кісткових дефектах. Сучасний остеосинтез почав своє формування наприкінці 1800-х на початку 1900-х років. Але деякі знахідки археологів підтверджують, що внутрішньокісткові або накісткові імпланти застосовувалися ще в стародавньому Єгипті, Китаї та Індії.
What are the types of osteosynthesis?
There are several types of osteosynthesis:
External (percutaneous) osteosynthesis means no intervention into the fracture area. Instead, it applies an external fixation device (a system by Ilizarov, Kostiuk, Volkov-Oganesian) with its wires and nails going through the bone above and below the fracture area.
Different external fixation devices
Internal osteosynthesis means the insertion of a fixing device into the fracture area. Internal osteosynthesis splits into three methods: perosseous, surficial, and intraosseous.
Internal perosseous osteosynthesis applies screws or wires to fix bone fragments. The fixing devices may be inserted into the bone transversely, longitudinally, or inclined. This method is beneficial for spiral fractures of finger phalanxes, fractures of calcaneal bone, patella, condyles, syndesmosis, ankles, etc.
Screws for perosseous osteosynthesis
Plating works most frequently for tubular bone fractures at any location and closed displaced fractures without complications (like transverse, comminuted or similar complex cases). Implants here are metal plates fixed to the bone with screws. In turn, contemporary implants for plating split into many different types: mini-invasive, with minimal contact, locking, biphase, etc.
Plates for bone fragments’ fixation in different areas
Internal intramedullary osteosynthesis works for tubular bone fractures of almost any location. There are two styles of internal osteosynthesis – open reduction internal fixation (ORIF) and closed reduction internal fixation (CRIF). ORIF consists of open surgery to set the bones without special devices, using only surgical instruments. CRIF requires a navigation tool insertion of a metal or polymeric-metal nail into the intramedullary canal. Usually, the procedure stipulates an X-ray of EOP control. However, modern navigation systems make it possible to do surgery without radiational supervision.
Nails for intramedullary osteosynthesis
Types of osteosynthesis also differ depending on the period from trauma to its surgical treatment. There are 2 of them:
- initial, when metal osteosynthesis occurs within the first 12 hours after the injury;
- delayed, when the surgery takes place 12 hours and more after the trauma.
The delayed osteosynthesis doesn't mean wasting time or lateness of medical aid. A surgeon decides on the type of operation appropriate for each specific case, relying on the patient's general health conditions, concomitant traumas and diseases, the availability of adequate implants in the operation rooms, etc.
Indications and contraindications. When to use each specific type of osteosynthesis?
Indications
Absolute indications of osteosynthesis: unstable fractures with significantly displaced fragments; comminuted fractures unable to fuse without repositioning and fixation. For instance: olecranon process and patella fractures with the discrepancy of bone fragments, some types of femoral neck fractures; intra-articular fractures (of femoral and tibial condyles, distal metaepiphyses of shoulder or radial bone); if a bone fragment threatens to perforate the skin, i.e. make the close fracture open, fractures accompanied with the interposition of soft tissues between bone fragments or those complicated with damage to a major vessel or nerve.
Contraindications
Only a patient's general health conditions could be an absolute contraindication. To avoid extra trauma, another narcosis, and probable blood loss, a surgeon may postpone the operation, waiting for the general conditions to stabilize.
The following may be relative contraindications to one or another method of osteosynthesis:
- blood diseases associated with its clotting disorders, low haemoglobin, sepsis
- acute infectious diseases, purulent skin lesions in surgical approach areas
- osteoporosis and metabolism disorders (need a different fixation method)
There are no accurate algorithms to determine the best method to fix fragments. Recommendations and scientific papers substantiate the benefits of this or that method for fractures in specific locations.
Relative and absolute indications for implants (in many cases) exist for open and closed fractures. Intraosseous and surficial types of osteosynthesis are not recommended for open fractures, especially if there is a risk of the fracture area’s infection. In these cases, external fixation devices are suitable. An external fixation device may be a constant method until the complete fusion or as a temporary one until soft tissue heals, and later replaced with an intramedullary nail or a minimal-contact bone plate.
Implants for osteosynthesis of the spine produced by ChM
Removal of implants after the osteosynthesis. Is the removal necessary?
Patients always ask if it is necessary to remove implants after osteosynthesis or if the nail, screw, plate, or wire could remain in the body to avoid additional surgery. In some cases, trauma surgeons could let the implants remain inside the bony forever, although their removal is necessary for the following situations:
- the surgical method predetermines the removal of the implants (locking nails and plates for intramedullary osteosynthesis);
- infection and purulent processes development (osteomyelitis);
- young age of the patient (the fixing device may prevent the growth of the segment);
- fracture nonunion after previous surgical treatment (to replace the unsuitable fixing device with another one);
- the implant causes an individual discomfort in specific locations (clavicle, elbow, ankles, calcaneal bone, hand, etc..);
- migration of implants
Advantages and disadvantages of fracture treatment using osteosynthesis
Osteosynthesis has the following benefits:
- recovery of a bone’s integrity without plater dressing promotes early rehabilitation and prevents contractures of adjacent joints;
- stable fixation in an anatomically correct position, matching the fragments;
- possibility to start walking before the fusion completes (only provided that the fixation is stable);
- suitability of the method for complex fractures with dislocations and displacements when plaster dressing is inefficient and harmful for joints (joints lose mobility after the fixation, contractures development is highly probable)
If the fixation method is correct, no complications occur, and rehabilitation starts in time, a patient may return to a habitual way of life within 3-6 months, depending on the localization of the fracture and the method of osteosynthesis chosen
Disadvantages
- Price of implants: some may cost tens of thousands of UAH.
- Removal of implants after the bone consolidation, i.e. one more surgery required
- Individual allergy to metal
Risks of complications:
- concomitant infection,
- breakage of the device due to a manufacturing defect, excessive load, repeated trauma (e.g. if a patient falls on the extremity with the implanted fixing device)
- nonunions of fractures due to the wrong choice of implants, fixation inconsistency, metabolic disorders (osteoporosis), or incorrect rehabilitation
- migration of implants
Appearance after different methods of osteosynthesis (plates, nails, screws, external fixation device)
Modern methods of osteosynthesis and snooping on the future
Among the last achievements in the sphere of surficial bone osteosynthesis, there were LCP plates, later – LPC plates with variable-angle-screws. A specific LCP screw has a bone thread in its lower portion and another - under its head. Threaded plate holes are compatible with the threaded portion of a screw's upper part to fix each screw tightly are reliably. This way of fixation prevents the migration of screws and enhances the stability of osteosynthesis.
There are LCP plates for every segment of long tubular bones. They correspond to the shapes and surfaces of the respective areas. Such anatomical pre-bending is very helpful at the stage of repositioning the fracture
A biphasic plate is another modern invention currently in the clinical trial process.
A system of periprosthetic proximal femoral variable angle LCP plates 3.5/4.5 of stainless steel. Plates on the image: proximal femoral plate with an additional ring for greater trochanter, extra variable angle locking plate, supplement loop plate for the distal femur.
Інтрамедулярні стержні з поліаксіальною стабільністю в 3-х площинах, анатомічні для різних сегментів з навігаційними системами, максимально спрощую імплантацію навіть без наявності ЕОПа або рентгена в операційній.
A modern system for intramedullary osteosynthesis of a tibia, with a navigator
Promising are elaborations in the sphere of biodegradable materials. Implants made of these materials don’t need removal. Unfortunately, such fixing devices have not gained wide clinical application yet.
To summarize
For many fractures, osteosynthesis is the only remedy to return a patient quickly to a habitual life, avoid contractures or other complications, typical of plaster dressings or durable skeleton traction. Osteosynthesis works for almost any bone or segment, from fingertips to spines and tips of toes. The wide variety of different fixing devices enables a surgeon to make an optimal choice to fix specific fractures. Each newly elaborated implant reduces the significance and frequency of probable disadvantages and complications. Bioinert materials contribute to avoiding some patients' intolerance and allergic reactions, while new alloys enable dosed load on injured extremities from the first days after the surgery.
