Principles of closed reduction

Closed reduction is always preferable to open reduction provided that a comparable reduction can be obtained and held. Closed reduction relies on the attachments of the bone to soft tissues (periosteum and/or ligaments) to obtain and to hold reduction. Intra-articular fractures, where fragments may not have any soft-tissue attachments, cannot usually be reduced closed. These fractures also need accurate reduction if traumatic secondary arthritis is to be avoided and so are best performed open to make sure that reduction is anatomical. In children the bones may not be clearly visible on X-ray because they have not yet fully ossified, especially around the elbow. Open reduction may be needed to be certain that reduction has been achieved (Table 21.4).

Pain relief

Patients need to be free of pain when reducing fractures, so a general anaesthetic will be required if a regional block is not possible. If there is no neurovascular compromise this is not an urgent operation, so time should he allowed for the patient’s stomach to empty before a general anaesthetic is administered. It may be best to send the patient home with a splint and analgesia so that the procedure can be performed as a semi-planned procedure on a fully staffed list the following morning. If there is any chance that the reduction will not be successful, and that the fracture will need to be opened, then this should be planned in advance (another good reason to leave the case over until the following morning). You will also need to plan how you are going to check that the fracture has indeed reduced satisfactorily, so you will need to book either an image intensifier or plain X-rays, and the patient will need to be positioned so that imaging in two planes is possible. You will also need to plan how to hold the fracture and what facilities (such as plaster or traction pins and frames) you will need.

Value of the periosteum

When a bone fractures the periosteum remains largely intact, especially on the concave side of the fracture. This strong membrane is not visible on the X-ray and so its value in guiding the fracture to a stable reduction may not always be fully appreciated. Impacted fractures which are also partially displaced will need disimpacting before the displace­ment can be corrected. Disimpaction is carried out by apply­ing steady distraction to the fracture until you feel the bone ends separate. The force applied should be no more than 4 or 5 kg as otherwise there is a danger (especially in the elderly) of degloving the limb (pulling off the skin and soft tissues). If the fracture does not initially disimpact, then the fracture should be bent further than it is already angulated, ‘exaggerating the deformity’. This manoeuvre should disengage the jammed ends. The limb will lengthen slightly, and the fracture will become floppy. Traction should be continued for another couple of minutes to drive oedema out of the tissues around the fracture. This will allow the soft tissues to extend to their normal length and make the reduction easier.

Engaging the bone ends

The intact periosteum on the concave side of the fracture can now block reduction unless the tension is taken off it. This is done by angulating the fracture even further than before, and sliding the fractured end of the distal fragment up the cortex of the proximal fragment until it slips over the broken edge of the proximal fragment. As soon as this occurs the fracture can be rolled into place with the jagged ends of the fracture interdigitating like gear wheels. When the fracture comes to anatomical alignment, the intact periosteum on what was the concave side will become tight and prevent overcorrection of the fracture. Providing that any lateral pressure exerted on the fracture is in the direction of overcorrection the fracture will remain stable, splinted by the periosteum.

Open reduction of fractures

Exposure of a fracture should allow adequate access to see as much of the fracture as necessary while minimising damage to soft tissues. It should also minimise damage to the periosteum, which will be providing the bulk of the blood supply to the broken bone fragments. If that blood supply is lost then the fracture cannot unite. The incision will have to take into account any wounds already present and should be extensile (able to be extended if necessary). If a plate is to be put on the bone the incision should be planned to enable the plate to be put on the side of the bone which will be in tension. If there is skin and soft-tissue loss then incisions should be planned with a plastic surgeon to ensure that skin and soft-tissue cover of the bone and fixation can be obtained at the end of the operation. Fractures which are conta­minated and those which are open (which must be treated as contaminated) are an emergency, but not a life-threatening one. Every hour that goes by increases the risk of the fracture becoming infected, so surgery needs to be performed as soon as the anaesthetist feels that it is safe.