انت هنا الان : شبكة جامعة بابل > موقع الكلية > نظام التعليم الالكتروني > مشاهدة المحاضرة

Lower limbs trauma 2010 \ third lecture

Patellar dislocation :

Dislocation of the patella is most common in adolescent females, particularly if there is any generalized ligamentous laxity. Dislocation is virtually always to the lateral side. Closed reduction under sedation may be needed, but many dislocations spontaneously reduce. Initial management is conservative with a programme of knee rehabilitation. Surgical stabilization can be considered for patients with recurrent troublesome instability.

Patellar fracture :

Fractures of the patella constitute almost 1% of all skeletal injuries, resulting from either direct or indirect trauma. The anterior subcutaneous location of the patella makes it vulnerable to direct trauma, such as the knee striking the dashboard of an automobile or from a fall on the anterior knee.

 These injuries often are comminuted or displaced and may include chondral injury to the distal femur or patella. Fractures caused by indirect mechanisms result from a violent contraction of the quadriceps with the knee flexed. These fractures usually are transverse and may be associated with tears of the medial and lateral retinacular expansions. Most patellar fractures are caused by a combination of direct and indirect forces. The most significant effects of fracture of the patella are loss of continuity of the extensor mechanism of the knee and potential incongruity of the patellofemoral articulation.

Fractures of the patella can be classified as undisplaced or displaced .Transverse fractures usually involve the central third of the patella, but can involve the proximal (apical) or distal (basal) poles.

A variable amount of comminution of the poles may be present. Most fractures  are transverse. Vertical fractures usually involve the middle and lateral thirds of the patella. If only the medial or lateral edge of the patella is affected, the fracture is called marginal.. Another common fracture pattern is the comminuted or stellate patellar fracture, which is associated with a variable amount of displacement.

Patellar fractures generally are associated with a hemarthrosis and localized tenderness. In fractures that are displaced or have concomitant retinacular tears, a palpable defect may be present. Inability of the patient to extend the affected knee actively usually indicates a disruption of the extensor, which require surgical treatment.

Treatment :

The initial treatment of acute patellar fractures should consist of splinting the extremity in extension or slight flexion and applying ice to the knee. To prevent soft-tissue damage, the ice should not be applied directly to the skin. Closed fractures with minimal displacement, minimal articular incongruity, and an intact extensor retinaculum can be successfully treated nonoperatively. Nonoperative treatment consists of immobilizing the knee in extension in a cylinder cast from ankle to groin for 4 to 6 weeks, with weight bearing allowed as tolerated..

Surgical treatment: Wiring techniques are used most often for transverse fractures. They also can be used in comminuted fractures if the fragments are large enough to lag together with screws, converting it to a transverse fracture. Many different wiring techniques have been described, including cerclage wiring, alone or in combination; tension band wiring, alone or modified with longitudinal Kirschner wires or screws.

Comminuted Patellar Fractures

Often, only the distal pole of the patella is fragmented, leaving a substantial and relatively normal proximal fragment. This fragment is an important part of the extensor mechanism and should be preserved. In case of severe comminution  patellectomy is the best option.

Tibia & Fibula Injuries  :

TIBIAL PLATEAU  FRACTURES

Fractures of the tibial plateau are more common in older patients. Most of these injuries occur as isolated fractures and less than 2% are associated with multiple trauma. Most tibial plateau fractures involve the lateral plateau. Valgus deformity of the knee is, therefore, the most common clinical finding. In medial plateau fractures varus deformity is present. Fractures involving both the medial and the lateral plateau (Bicondylar fractures) account for 10% of plateau fractures and are consequences of high-energy trauma. Extensive swelling and bruising is commonly associated with this fracture pattern. Medial tibial plateau fractures occur as a result of forced varus deformity and are associated with common peroneal nerve palsy in 10% of cases.

Imaging :

Plain radiographs are sufficient in most cases to establish the diagnosis. In cases where the extent of displacement is uncertain or in complex injury patterns then a CT scan is the most useful additional investigation.

Management:

Undisplaced plateau fractures are infrequent, but if there is no articular surface displacement they can be treated non-operatively in a plaster cast or hinged knee brace, touch weight-bearing for 6 weeks. Radiographs are carried out in the first 2 weeks to ensure no displacement occurs.

Fractures with articular displacement are an indication for operative treatment in a fit patient. Internal fixation using screws or plates is the usual treatment method. External fixation can be used and may be a safer choice in patients with extensive soft-tissue injury.

The clinical outcome is satisfactory in most patients. Wound complications affect  5% of patients. Deep venous thrombosis is an occasional problem also. Stiffness will occur in 5% of patients and may require a manipulation under anaesthesia to restore knee flexion after fracture union. The main long-term risk is osteoarthritis of the knee. Some degree of post-traumatic degenerative change is observed in 50-70% of patients within 10 years of injury, but total knee replacement is required in only 5% of cases.

In children fractures of the tibial spine are the commonest intra-articular fracture of the proximal tibia and correspond to a rupture of the ACL in the adult . A fall on the flexed knee is a common mechanism of injury. The ACL stretches before the tibial spine is avulsed. The child presents with a large haemarthrosis and treatment depends on the degree of displacement as seen on the lateral X-ray of the knee. An undisplaced fracture can be managed non-operatively, but significant displacement is an indication for internal fixation of the avulsed fragment.

Fibula Diaphysis Fractures

Isolated fibula fractures can be associated with other injuries of the leg, such as fracture of the tibia or fracture-dislocation of the ankle joint. One should pay particular attention to the medial malleolus to rule out deltoid ligament rupture or medial malleolus fracture. Isolated fibula fracture can be the result of a direct or "tapping" mechanism; however, it can also coincide with syndesmosis disruption. If reduction of the mortise is congruent, radiographic follow-up needs to be careful to ensure maintenance of reduction.

Tibia Diaphyseal Fractures

Isolated fractures of the tibial diaphysis are usually the result of torsional stress. There is a tendency for the tibia to displace into varus angulation because of an intact fibula.

Fractures of both the tibia and fibula are more unstable, and displacement can recur after reduction. The fibular fracture usually heals independently of the reduction achieved. The same does not apply to the tibia. There is some controversy as to what is an acceptable reduction of a tibial shaft fracture in the adult. The following criteria are generally accepted: apposition of 50% or more of the diameter of the bone in both anteroposterior and lateral projections, no more than 5 degrees of varus or valgus angulation, 5 degrees of angulation in the anteroposterior plane, 10 degrees of rotation, and 1 cm of shortening. It is assumed that fracture healing in an unacceptable position (ie, malunion) will affect the mechanics of the knee or ankle joint and possibly lead to premature degenerative joint disease.

Acceptable reduction can be obtained in one of many ways, and this is another area of ongoing controversy: closed versus open treatment. The goal of any treatment is to allow the fracture to heal in an acceptable position with minimal negative effect on the surrounding tissues or joints. Closed reduction is obtained under general anesthesia if necessary, and the patient is immobilized in a long leg non-weight–bearing cast. Weekly radiographs for the first 4 weeks will help ensure that displacement does not occur. If it does, angulation can be corrected by "wedging" the cast. This involves dividing the plaster circumferentially and inserting wedges in the appropriate direction after corrective manipulation. At 6 weeks, some shaft fractures are stable enough to be put in a short leg weight-bearing cast, usually a patellar tendon-bearing cast( PTB cast) or brace . Protected weight bearing should be continued until clinical and radiologic healing is evident.

If acceptable and stable reduction cannot be obtained by closed means, other methods are required. Skeletal traction via a calcaneal transfixing pin is rarely used, although it is an acceptable short-term option in the polytraumatized patient. An external fixator with an outer frame is extremely useful for open fractures, as it provides rigid fixation and still allows access for wound care. This is still the initial treatment for some Gustilo type 3 injuries and in the hemodynamically unstable patient. A reamed intramedullary nail is the recommended treatment for most displaced closed fractures. Intramedullary nails are introduced from a proximal starting point anterior to the tibial tubercle and across the fracture site under fluoroscopic control without opening the fracture site.

Open reduction and internal fixation with plates and screws using minimally invasive percutaneous plate osteosynthesis (MIPPO) techniques, avoids direct exposure of the fracture site and decreases soft-tissue dissection, devascularization of the bone, risk of infection, and delayed union. This technique is useful in periarticular fractures with diaphyseal extension.

Disadvantages of operative treatment include infection, wound problems. The advantages of closed treatment are early mobilization with or without weight bearing and a short hospital stay, with less risk of infection from the operative approach. Closed conservative treatment does not preclude further surgical treatment. Disadvantages include residual deformity, knee or ankle joint stiffness, and more difficult wound care. Sound clinical judgment is needed in the decision-making process.