The Knee
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Randomized Controlled Trial Comparative Study
Biomechanical analysis of four different fixations for the posterolateral shearing tibial plateau fracture.
The posterolateral shearing tibial plateau fracture is uncommon in the literature, however with the increased usage of computer tomography (CT), the incidence of these fractures is no longer as low as previously thought. Few studies have concentrated on this fracture, least of all using a biomechanical model. ⋯ Vertical displacement of the posterolateral fragment was measured using three different strengths of axial loading force, and finally loaded until fixation failure. It was concluded that the posterolateral buttress plate is biomechanically the strongest fixation method for the posterolateral shearing tibial plateau fracture.
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Randomized Controlled Trial Comparative Study
Mobile bearing UKA compared to fixed bearing TKA: a randomized prospective study.
We prospectively evaluated a consecutive series of 56 patients with unicompartmental knee arthritis who underwent unicompartmental knee replacement or total knee arthroplasty and received an average of 52months of follow-up. These patients were enrolled in a prospective randomized clinical trial. There were no significant differences in the pre-operative parameters of both groups. ⋯ Seven cases of UKA were converted to total knee arthroplasty - all of them within the first 2years of starting the procedure and all of them in relatively young patients. From the study we concluded that mobile bearing UKA can obtain similar clinical effect with TKA by surgeons who have the adequate training and experience. After the learning curve UKA should be considered the primary treatment option for unicompartmental knee arthritis.
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A 62year old man developed a compartment syndrome of the thigh after total knee arthroplasty. Twelve years previously he had a HTO of the same knee complicated by a compartment syndrome of the calf. ⋯ Compartment syndrome of the thigh is a rare, but potentially devastating, complication following total knee arthroplasty. A previous compartment syndrome of the calf is identified as a risk factor.
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Varus thrust is an abnormal lateral knee motion frequently seen in patients with medial knee osteoarthritis (OA) during gait. It is a worsening of the alignment in the stance phase of the gait cycle and closely relates to disease progression. In this study, we measured the thrust quantitatively using skin markers and examined the relationship to other static and dynamic parameters. ⋯ The amounts of thrust in subjects with K-L grades 2 (25 knees), 3 (13 knees), and 4 (6 knees) were 2.4°(±1.3°), 2.8°(±1.4°), and 7.2°(±5.3°), respectively and the knee adduction moments were 3.6(±1.5) %BW⁎Ht, 3.9(±1.2) %BW⁎Ht and 6.9(±2.2%) BW⁎Ht, respectively. The amount of thrust also exhibited significant correlation to static radiographic alignment (R=0.47: 95% confidence interval 0.67-0.21, p=0.0038) and showed greater correlation to the knee adduction moment (R=0.73: 95% confidence interval 0.84-0.55, p<0.001), which has been identified as an important dynamic index of the disease. The amount of thrust, which is able to be measured by simple inexpensive equipment, correlated to static and dynamic parameters and may offer an important clinical index for knee OA.
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We present two case reports with clinical and radiological assessment of the anatomical features at the distal lateral end of trochlea and femur in patients with patellar instability in higher knee flexion and how these findings could possibly be involved in the genesis of this rare type of patellar instability. Both patients underwent several (nine and seven) surgical procedures, but the patellar instability could not be successfully eliminated. Our hypothesis was that a short and flattened lateral distal condyle/trochlea may cause lateral patellar instability in higher flexion. ⋯ With these procedures, lateral patellar instability with increased flexion could be completely eliminated in both patients at the 1- and 2-year follow-up. Our experience of assessment and treatment of these patients let us conclude that variations of the distal lateral femoral condyle/trochlea morphology may be responsible for patellar instability with increased flexion. This is another type of patellar instability caused by distal condyle/trochlea dysplasia compared to the well known and often described types of patellar instability close to extension caused by proximal trochlea dysplasia.