Articles: tibia-surgery.
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Arch Orthop Trauma Surg · Jan 1999
Comparative StudyPrimary stability of different implants used in conjunction with high tibial osteotomy.
High tibial osteotomy in the varus knee has been successfully performed for a long time. Several newer operation techniques have been established in recent years. We tested the primary stability of several of these techniques in vitro. ⋯ If the medial cortex is transected intraoperatively in lateral osteosynthesis, an additional medial implant is necessary to ensure sufficient primary stability. For practical reasons it was necessary to neglect the contribution of the soft tissues around the knee, although all implants were tested under the same conditions. Care should thus be taken when interpreting the results of this study in a clinical setting.
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This biomechanical study evaluated the static response of a new opening-wedge osteotomy plate to compression and torsion loads in a human cadaver model. This plate incorporates a metal block that distracts the medial tibial cortices to ensure precise correction and prevent bone collapse. The 15-mm plate was inserted into 23 fresh cadaver specimens using a standard surgical technique. ⋯ This opening-wedge osteotomy plate construct appears marginally strong enough to withstand the estimated axial load on the proximal tibia during gait. Estimated torsional load on the knee during level walking slightly exceeds the failure load prior to osteotomy healing. This information can be used to guide further experimental protocols for static and dynamic testing of this device to determine the appropriate rehabilitation guidelines following opening-wedge proximal tibial osteotomy.
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Arch Orthop Trauma Surg · Jan 1999
Loss of correction after lateral closing wedge high tibial osteotomy--a human cadaver study.
In 12 human cadaver tibiae, osteotomies were carried out at two levels (2 and 3 cm from the distal joint line) with three different wedges (5 degrees, 10 degrees, 15 degrees) to evaluate the influence of displacement of the osteotomy fragments on areas of cortical contact. In undisplaced osteotomies (medical cortical edges superposed) cortical contact areas formed 28% (level 2 cm) and 40.5% (level 3 cm) of the cortical circumference of the proximal fragments (NS). Wedge angles and levels of osteotomy displayed no statistical differences. ⋯ Displacing the distal fragment laterally, medial cortical contact is lost, and weight-bearing leads to revarisation as cancellous bone sustains only 3 MPa, and the measured compressive stresses at the medial edge amounted to 6 MPa on average. Displacing the distal fragment medially leads to a decrease of total cortical contact, too, but at the medial edge of the osteotomy cortical contact areas are still present. As a result of the study, postoperative weight-bearing without additional plaster cast fixation is recommended only in cases with undisplaced fragments.
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Arch Orthop Trauma Surg · Jan 1999
Substitution of tibial bony defects with allogeneic and autogeneic cancellous bone: encouraging preliminary results in 18 knee replacements.
Eighteen knee replacements in 15 patients with severe gonarthritis or loosening of total knee arthroplasty (TKA) requiring bone grafting for bony deficiencies were studied before and after operation. The average follow-up was 2.4 years. Fifteen knees showed satisfactory clinical and radiographic results of the integration of the bone grafts. ⋯ Two of 3 knees with loosening of the tibial component required revision. These results are encouraging. Success depends as much on rigid fixation of the grafted bone and protected weight-bearing as on rigid, micromotion-preventing fixation of the tibial component.
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Arch Orthop Trauma Surg · Jan 1999
High tibial osteotomy: factors influencing the duration of satisfactory function.
In 94 patients 112 knees were examined after high tibial osteotomy for varus and valgus gonarthrosis. Preoperatively, there were 71 varus and 23 valgus deformities. The mean follow-up period was 9.0 years (range 2-21 years). ⋯ The data were subjected to multivariate statistical analysis in which three of four evaluated risk factors were found to be associated with the duration of pain-free survival: certain preoperative injuries, preoperative meniscopathies and a deterioration of the stage of arthrosis (P < 0.05). There was no significance for weight in excess of 10% above the normal body mass index (BMI) limits. However, in a Kaplan-Meier survival analysis this parameter could be determined as a significant factor for a reduced pain-free survival interval (P < 0.05): patients with a BMI of more than 10% above normal limits had a pain-free period of 5.07 years, whereas those with a BMI of less than 10% had a pain-free period of 7.80 years.