Bmc Musculoskel Dis
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Bmc Musculoskel Dis · Jun 2013
Study of surgical indication for knee arthroplasty by cartilage analysis in three compartments using data from Osteoarthritis Initiative (OAI).
Bicompartmental or unicompartmental knee arthroplasty (BKA, UKA) is currently advocated as an alternative solution to conventional total knee arthroplasty (TKA) in order to preserve bone stock and ligaments for limited osteoarthritis (OA) with intact anterior and posterior cruciate ligaments (ACL, PCL). However, the actual rate of UKA or BKA compared to TKA procedures in OA patients has not been reported. In this study, we retrospectively analyzed preoperative MRI of the knee in subjects who underwent knee arthroplasty and assessed the potential for UKA or BKA as an alternative treatment. ⋯ Many medial or lateral compartmental OA subjects, with or without patellar compartment defects have undergone TKA. The results of this study suggest the indication for partial arthroplasty, such as UKA or BKA, may increase when cartilage in each compartment, as well as ligaments and subchondral bone status are comprehensively evaluated.
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Bmc Musculoskel Dis · Jun 2013
Effects of cord pretension and stiffness of the Dynesys system spacer on the biomechanics of spinal decompression- a finite element study.
The Dynesys system provides stability for destabilized spines while preserving segmental motion. However, clinical studies have demonstrated that the Dynesys system does not prevent adjacent segment disease. Moreover, biomechanical studies have revealed that the stiffness of the Dynesys system is comparable to rigid fixation. Our previous studies showed that adjusting the cord pretension of the Dynesys system alleviates stress on the adjacent level during flexion. We also demonstrated that altering the stiffness of Dynesys system spacers can alleviate stress on the adjacent level during extension of the intact spine. In the present study, we hypothesized that omitting the cord preload and changing the stiffness of the Dynesys system spacers would abate stress shielding on adjacent spinal segments. ⋯ The results reveals that removing the Dynesys system cord pretension attenuates the ROMs, disc stress, and facet joint contact forces at adjacent levels during flexion and axial rotation. Removing cord pretension together with softening spacers abates stress shielding for adjacent segment during four different moments, and it provides enough security while not jeopardizes the stability of spine during axial rotation.