Treatment

What treatments should I consider?

Nonsurgical Treatment

Because of the wide variety of fractures that occur around the knee there are a large number of different treatment options. Traction, cast immobilization and surgery have all been used.

This method of treating fractures depends on the fact that stretching out the injured part tends to pull the bone fragments into better alignment. When traction is applied, the ligaments and soft tissue between the fragments pull tight and aligns the bone fragments. If you pull a string of beads taut they line up and the same it true for fracture fragments.

Traction is maintained for several weeks until the healing process has advanced to the point where healing bone is beginning to form between the fragments. This new bone is called callus. Callus can be seen on x-ray, so the surgeon depends on the x-rays to determine when the callus is sufficient to hold the bone fragments together. Bone fragments bonded together with callus should be stable and not move out of position. At this point the traction can be removed and the patient mobilized. A cast or special fracture brace is usually needed at this stage and weight-bearing is not permitted until the fracture is consolidated.

Traction is usually applied under an anesthetic. A stainless steel pin is placed through the shin bone below the fracture. The lower part of the leg is supported in a splint and weights are attached to the pin to keep a constant pull on the bone. Traction can be used for supracondylar fractures of the femur or tibial plateau fractures.

Special hinged splints are used so that the knee can bend while the traction is maintained. This is valuable for nutrition of the joint and helps prevent later stiffness of the knee. Although applying traction may require an anesthetic, it is not a major operation. It causes less stress on the system and may be preferable when other medical conditions make surgery more risky.

The primary disadvantage of traction treatment is that the fracture fragments may not return exactly to their normal position. This mal-reduction can be a problem if it leaves the joint surface irregular. Treatment with traction also requires a long time of immobilization in hospital.

For nondisplaced fractures of any part of the knee, immobilization of the knee is an option. This is the normal treatment for most avulsion fractures, unless ligament reconstruction surgery is also needed. The cast is applied from thigh to ankle leaving the foot out of the cast. If the cast treatment is for an nondisplaced supracondylar fracture or a tibial plateau fracture the knee is usually held in 45 degrees flexion inside the cast. Nondisplaced fractures of the kneecap are rare but may be treated in a cast with the knee straight. With cast treatment one can expect to have x-rays done at intervals during the healing period to make sure the fracture does not displace.

A cast is often also applied after a period of traction. The initial cast may be changed at four to six weeks post injury. An x-ray at this stage is used to confirm that the position of the fracture is still acceptable and to assess the progress of healing. A second cast or a removable splint is then applied. If the splint is removable the surgeon may recommend you take it off and do non-weight-bearing exercises to bend and straighten the knee once or twice a day. Weight-bearing is allowed once there are X-ray signs of adequate healing.

Treatment of fractures in a cast seems simple and understandable. No operation is required and most casts can be applied without an anesthetic. But, cast treatment has disadvantages. The fracture fragments may not be accurately reduced or may displace during the healing period leading to malunion. Prolonged immobilization in a cast may lead to stiffness of the knee. The difficulty in recovering range of motion may result in later wear-and-tear changes and arthritis of the joint.

Cast treatment may make full recovery longer because the cast immobilization is continued until healing has occurred. Once healing is adequate to begin physical therapy, the knee is stiff and the muscles of the leg are weak. Recovering normal function then requires a longer period of rehabilitation.

The most popular method of surgical treatment of knee fractures in North America is open reduction and internal fixation (ORIF). This means that the fracture site is exposed through an incision in the skin (open), the fracture fragments are moved back into the correct position (reduction) and then held in place by metal implants such as pins, screws and plates (fixation). The fixation devices are left on the bone and the wound is closed.

The intent of this surgery is to hold the bone fragments rigidly in place and allow movement of the joint while the bone is healing. Weight-bearing is not permitted until the bone is healed, otherwise the fixation devices would bend or fail by metal fatigue. There is a great advantage to have the joint move again soon after the surgery. Early motion reduces the risk of stiffness and arthritis of the knee. Motion also shortens the period of recovery. Healing, recovery of movement and strengthening can proceed together.

Treatment of some knee fractures is possible using the minimally invasive procedure of arthroscopy. In this technique a small camera is inserted into the joint and the fragments can be manipulated using the camera to visualize the inside of the knee. This can be used to retrieve and remove a loose osteochondral fracture fragment. If more complicated repair of the ligaments or muscle attachments is required, arthroscopy may be combined with open incisions to allow the surgeon to fix these injuries as well.

Avulsion fractures of the tibial spines may also be reduced and fixed using an arthroscopic technique alone. Certain very simple tibial plateau fractures can also be reduced and fixed using arthroscopic technique. One assumes that this approach will be expanded in the future as techniques are developed to reduce more complex fractures arthroscopically.

Where the attachment of tendon or ligament has been pulled off it may be necessary to fit the bone fragment back to the exact site it came from in order to restore the normal function of the tendon or ligament. For example, avulsion of the patellar ligament from the tip of the patella or the tibial tubercle would normally be treated by opening up the site of the injury, replacing the fragment in the correct position and fixing it with a small screw. The strain is taken off the repair by passing a wire transversely through the kneecap then circling round to pass through the tibia below the tubercle. This wire then absorbs the pull of the muscle until the fracture fragment has healed in position.

If surgery is chosen for treatment of these fractures it can be undertaken by an intramedullary nail or by a plate applied to the outer side of the lower end of the femur.

In the first technique in incision is made into the knee. Any intra-articular fragments are reduced accurately and fixed with pins or screws; this is to ensure that the joint surface is restored to smoothness. Then a rod is passed up into the intact upper part of the bone and fixed with transverse screws. The lower part of the bone is also fixed to the rod; thus all fracture fragments are held immobile and in good position by the metal rod inside them. This technique has the advantage that exposure of the fracture fragments can be quite limited with less disturbance of the blood supply of the bone.

Some surgeons are concerned that the technique enters the knee joint and may cause later damage from small pieces of bone floating in the joint. There is also an issue about entering the knee joint again to remove the rod if that becomes necessary after the fracture heals.

The second method of treating supracondylar fractures involves exposing the bone fragments from the outer side, moving them back into position (reduction) and fixing them by a long metal plate fixed to the bone above and below the fracture. A variation of this technique involves indirect reduction of the fracture fragments with minimal exposure. The plate is slid up under the muscle so that the blood supply is not disturbed.

Depending on the anatomy of the fracture the inner or the outer side of the upper end of the tibia is exposed. Exposing a fracture means that an incision is made and enough of the tissue surrounding the fracture is moved aside so that the fracture can be seen good enough to repair it. The fracture fragments are then reduced, paying particular attention to the joint surface. It is common for parts of the joint surface to be broken and pushed down inside the bone. This is referred to as a depressed tibial plateau fracture. These fragments need to be lifted up, or elevated, and held in position by plates and screws. The plate extends down on the side of the shin bone to provide fixation above and below the fracture.

Bone graft is often used to add support for the depressed fragments. It is sometimes impossible to restore the smoothness of the joint surface exactly and in other cases there is extensive irreparable damage to the joint surface. In those situations the aim of fracture treatment is to preserve the correct overall shape of the bone so that a later knee replacement can be done.

In some cases, a less invasive technique may be recommended as treatment. This minimally invasive technique for tibial plateau fractures uses a combination of open reduction for the joint surface and an external fixation frame for the rest of the fracture. The frame consists of strong pins passed through the skin and into the bone above and below the fracture. These pins are then attached to a ring system outside the leg. The rings are connected by strong bars and the whole assembly holds the fracture fragments still while healing takes place.

The main advantage of this technique is that there is less exposure and disturbance of the blood supply. Unfortunately, there is a risk of infection of the pin sites and this limits the applicability of this technique.

Operative treatment for displaced fractures of the kneecap is the norm. The fracture is exposed and the fragments brought together accurately. The joint surface is the important consideration and every effort is made to avoid a ridge or step in the joint surface. The position of the fragments is then maintained by passing stainless steel wires through the fragments and reinforcing this with a wire that goes round the pins, often in a figure of 8 fashion.

It is usually not necessary to put a cast on the leg after this operation but weight-bearing is not permitted until the x-ray shows signs of healing. The fracture will pull apart and the pins break if pulled on by the strong quadriceps muscle too early.

The amount of damage to the bones at the knee can be severe. In these cases it may be valuable to assist the healing process by adding bone graft. When this is considered necessary, the bone is usually harvested from the rim of the pelvis. A small incision is made above the hip, the pelvic bone is exposed and a piece of bone is removed. The bone graft pieces are shaped to fit and packed into the fracture defect.

Bone graft assists the healing process and supplies some mechanical strength. It is used quite frequently in supracondylar fractures of the femur and in tibial plateau fractures. There is on-going research into substitutes for bone graft to facilitate the healing process and remove the need for the operation to harvest bone graft.

Patients usually ask whether implants to treat fractures will need to be removed later. The answer is: it depends. The pins used in the external frame are always removed once the fracture has started to heal. A choice must be made about removal of other types of hardware. Quite often there are symptoms of aching, cold sensitivity and tenderness which are related to the hardware. If these symptoms warrant it the hardware (metal plates, rods, pins and screws) can be removed.

An operation to remove hardware is often viewed with concern by many patients because of the pain experienced after the initial operation and because of concern about re-fracture. Much of the postoperative pain after the original fracture is from damage to the muscle and other soft tissue in the original injury. This damage is not repeated when the hardware is removed to the post-operative pain is usually much less severe and the operation does not usually require a hospital stay.

Re-fracture after hardware removal in the leg is rare although most surgeons limit sports and other heavy activity for a few weeks as a precaution. The bone does not become significantly weaker once the hardware has been removed.

Some cultures prefer hardware to be removed even if there are no symptoms. There is also a school of thought among orthopaedic surgeons that plates should be removed because they shield the bone from stress. Since bone responds to stress by getting stronger, theoretically this stress shielding might make the bone relatively weak. There is not enough evidence that stress shielding actually causes problems later in life to convince all surgeons to subject their patients to a hardware removal operation when there are no symptoms.