RESUMO
BACKGROUND: Patients with hip instability due to cerebral palsy, hemiplegia, infantile paralysis and extensive damage in gluteus medius, appear with high dislocation rate after arthroplasty, which is a great challenge for clinicians.OBJECTIVE: To investigate the reconstruction of the hip joint stability with the dual-mobility acetabular cup, and to prevent the dislocation after replacement in patients with hip neuromuscular lesions.METHODS: Twelve cases of hemiplegia, infantile paralysis, developmental dysplasia of the hip and recurrent dislocation after hip arthroplasty admitted in the Orthopedic Treatment Center, the Second Affiliated Hospital of Henan University of Chinese Medicine from January 2010 to July 2014 were enrolled, then underwent joint replacement or revision with dual-mobility cup, and the dynamic stability of the hip was achieved by adjusting the abductor lever arm.RESULTS AND CONCLUSION: (1) The followed-up time was from 20 to 60 months. (2) One year later, one case suffered Vancouver A right femoral fracture and received conservative treatment at 1 year postoperatively; one case of dislocation at postoperative 1 week, and dislocation, infection and loosening occurred in none cases. (3) These results manifest that those patients with neuromuscular disease and hip instability treated with hip joint arthroplasty using dual-mobility acetabular cup can reconstruct the stability of the hip joint and prevent the occurrence of postoperative dislocation.
RESUMO
This study was aimed to estimate the effect of different ProDisc-C arthroplasty designs after it was implanted to C5-C6 cervicalspine. Finite element (FE) model of intact C5-C6 segments including the vertebrae and disc was developed and validated. Ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model and the curvature of the ProDisc-C prosthesis was varied. All models were loaded with compressed force 74 N and the pure moment of 1.8 Nm along flexion-extension and bilateral bending and axial torsion separately. The results indicated that the variation in the curvature of ball and socket configuration would influence the range of motion in flexion/extension, while there were not apparently differences under other conditions of loads. The method increasing the curvature will solve the stress concentration of the polyethylene, but it will also bring adverse outcomes, such as facet joint force increasing and ligament tension increasing. Therefore, the design of artificial discs should be considered comprehensively to reserve the range of motion as well as to avoid the adverse problems, so as not to affect the long-term clinical results.
