Knee dislocation is a relatively rare injury but an important one to recognize because coexistent vascular injury, if missed, often leads to limb loss. In addition, knee dislocation often presents in the context of multisystem trauma or spontaneous relocation, which makes detection more difficult.
More than half of all dislocations are anterior or posterior, and both of these have a high incidence of popliteal artery injury. Twenty to thirty percent of all knee dislocations are complicated further by open joint injury.
The finding of varus or valgus instability in full extension of the knee is suggestive of a spontaneously reduced yet grossly unstable dislocation. In addition, pain out of proportion, or absent or decreased pulses are red flags of such an injury.
Patellar pain is common in both athletic and nonathletic individuals. Among athletes, men tend to present with more patellofemoral injuries, including traumatic dislocations, than women. In the nonathletic population, women present more commonly with patellar disorders.
indirect trauma or force : With sudden changes in direction, usually happened with athletes due to suddon, severe contraction of the quadriceps muscle while the knee is stretched in valgus and external rotation.
Lower leg fractures include fractures of the tibia and fibula. Of these two bones, the tibia is the only weight bearing bone. Fractures of the tibia generally are associated with fibula fracture, because the force is transmitted along the interosseous membrane to the fibula.
The skin and subcutaneous tissue are very thin over the anterior and medial tibia and as a result of this; a significant number of fractures to the lower leg are open. Even in closed fractures, the thin, soft tissue can become compromised. In contrast, the fibula is well covered by soft tissue over most of its course with the exception of the lateral malleolus.
Tibial shaft fractures usually present with a history of major trauma. An exception to this is a toddler's fracture, which is a spiral fracture that occurs with minor trauma in children who are learning to walk.
Initially, all tibial shaft fractures should be stabilized with a long posterior splint with the knee in 10-15° of flexion and the ankle flexed at 90°. Admission to the hospital may also be necessary to control pain and to monitor closely for compartment syndrome.
Closed fractures with minimal displacement or stable reduction may be treated nonoperatively with a long leg cast, but cast application should be delayed for 3-5 days to allow early swelling to diminish. The cast should extend from the mid thigh to the metatarsal heads, with the ankle at 90° of flexion and the knee extended. The cast increases tibial stability and can decrease pain and swelling.
Early ambulation with weight bearing as tolerated should be encouraged. Tibial shaft fractures treated with casting must be monitored closely with frequent radiographs to ensure that the fracture has maintained adequate alignment. Adequate callus formation generally takes 6-8 weeks before cast therapy can be discontinued.
Despite proper casting techniques and adequate follow-up, not all nonoperatively treated tibial shaft fractures heal successfully. In addition, 6 weeks without knee motion often results in a stiff joint.
In general, however, better results are reported with internal fixation of displaced tibial shaft fractures than with nonoperative treatment. The results of nonoperative treatment of displaced tibial shaft fractures were not as satisfactory as those with intramedullary nailing.