Background: Ipsilateral fractures of femur and tibia, the so called “floating knee” are usually the result of high-energy trauma. They are associated with increased risk of local soft tissue injures around the knee including ligamentous injuries, delayed union, and more importantly, vascular injuries. We are reporting our experience with such fractures in a teaching hospital. Methods: A cross sectional study of “floating knee” injuries treated in Shahid Bahonar hospital of Kerman over a 1 year period (2003 to 2004) was performed. Seventy eight patients (69 males, 9 females), with a maximum follow-up of 2 weeks entered the study and are reported here. The injury type and, in particular, the vascular status of the limb in terms of prevalence and the fate of limb in first two weeks were the points of concern. Seventy eight “floating knee” patients comprised the study group that was divided into six groups in accordance with the limb vascular status. Group 1: Forty nine cases with normal pulses and normal capillary refill; group 2: Seven cases with low blood pressure and poor pulse, but intact capillary refill; group 3: Thirteen cases with no pulse and no capillary refill, and ischemic time of below 6 hours that had angiographic studies; whit severe crushing and vascular compromise referring 24 hours later who underwent amputation; group 6: Two patients who developed vascular compromise after fracture fixation. Each “floating knee” case was further classified according to the level and type of each bone fracture. Results: Out of 78 cases 18 had no pulse and did not regain any hemodynamic stabilization, and 13 had angiography and 5 went directly for arterial exploration. In general 15 cases (19.2%) of “floating knee” had vascular compromise, 8 of whom ended up with amputation. The vascular damage had no direct correlation with age, or anatomic location of fractures. Discussion: Simultaneous ipsilateral fractures of femur and tibia are associated with around 20 percent chance of vascular injury. Careful and immediate assessment of limb circulation is mandatory for any “floating knee” injuries.

Background: Simultaneous knee ligament injury with ipsilateral diaphyseal leg fracture happens not infrequently. Such injury could be missed on original evaluation of the broken limb. We report the prevalence of such occurrence in isolated ipsilateral diaphyseal leg fractures.Material and Methods: Eighty-two cases of diaphyseal leg fractures were enrolled in this study during a 18-month period. All these cases had a thorough examination of knee ligaments in the operating room following internal fixation of their fractures.Results: Of 82 cases 87.8 percent were male. Their average age was 27.2 years and 65.8 percent were involved in motorcycle accident. Sixteen cases (19.5%) with ligamentous injury were observed which included 8 patients (9.7%) with medial collateral injury (MCL), 6 (7.3%) anterior cruciate ligament (ACL) tear, 2 (2.4%) lateral collateral ligament (LCL) injury and 2 (2.4%) posterior cruciate ligament (PCL) tear and in two cases simultaneous injury of MCL and ACL occurred.Conclusions: Ipsilateral diaphyseal leg fractures, even in isolation, are associated with high risk of ipsilateral knee ligament injuries. This is an important fact to remember when dealing with such fractures.

Background: Simultaneous knee ligament injury with femoral shaft fracture happens not infrequently. Such injuries may be missed on initial evaluation of the broken limb. In this study we report the prevalence of knee ligament injury in a group of isolated femoral fractures.Materials and Methods: A total of 125 patients with isolated femoral fractures entered to this study and followed for 24 months. After fixation of their fractures, all patients underwent a thorough examination of knee ligaments in the operating room.Results: Among these 123 cases 75.1% were male. Mean age was 26.2 years. There were 39 patients (31.2%) with simultaneous ligamentous injury. The types of ligamentous injury were as follow: medial collateral ligament (18), posterior cruciate ligament (12), lateral collateral ligament (6), and anterior cruciate ligament (3).Conclusion: Based on the above findings, it is recommended to have a high index of suspicion for co-existence of knee injuries in ipsilateral fracture of femoral shaft.

Ipsilateral fractures of the femur and tibia result in a flail knee joint condition referred to as “ floating knee” . Associated knee ligament injuries are common and have been reported to be frequently missed in initial evaluations. We report the diagnosis and treatment of the concomitant patellar tendon rupture during fixation of the distal femur and proximal tibia fractures in a patient who presented with floating knee and a history of osteomyelitis. This case further highlights the paramount importance of careful assessment of the knee in patients who present with floating knee injuries. We also recommend that MRI and ultrasonography be used to prevent ignored patellar tendon ruptures in such patients; particularly when physical exam is challenging or an intra-articular injury is present.

Case A 13-year-old boy presented to the ski clinic following a fall and a possible twisting of his right knee. He was not able to bear any weight on his right leg and was experiencing pain in the medial aspect of his right knee. His past medical and surgical histories were unremarkable and he was otherwise in good health. Physical examination revealed no ecchymosis or effusion.He had moderate tenderness over the medial femoral condyle. Stress valgus test did not reveal any laxity, but caused significant pain. Plain radiography was performed (Fig.1).How do you interpret his radiographs.A. Enchondroma of the medial distal femur.B. Nonossifying fibroma of the medial distal femur.C. Osteoid osteoma of the medial distal femur.D. Salter-Harris type II fracture of the distal femur.

Background: Lower extremity injuries are frequently observed in car-to-pedestrian accidents and due to the bumper height of most cars, knee joint is one of the most damaged body parts in car-to-pedestrian collisions. Objective: The aim of this paper is first to provide an accurate Finite Element model of the knee joint and second to investigate lower limb impact biomechanics in car-to-pedestrian accidents and to predict the effect of parameters such as collision speed and height due to the car speed and bumper height on knee joint injuries, especially in soft tissues such as ligaments, cartilages and menisci. Materials and Methods: In this analytical study, a 3D finite element (FE) model of human body knee joint is developed based on human anatomy. The model consists of femur, tibia, menisci, articular cartilages and ligaments. Material properties of bones and soft tissues were assumed to be elastic, homogenous and isotropic. Results: FE model is used to perform injury reconstructions and predict the damages by using physical parameters such as Von-Mises stress and equivalent elastic strain of tissues. Conclusion: The results of simulations first show that the most vulnerable part of the knee is MCL ligament and second the effect of speed and height of the impact on knee joint. In the critical member, MCL, the damage increased in higher speeds but as an exception, smaller damages took place in menisci due to the increased distance of two bones in the higher speed.