Preventive cobalt therapy in heterotopic ossification consequent to prosthetic hip reimplantation.

Prosthetic hip reimplantation is considered to be a procedure at risk for the development of periprosthetic heterotopic ossification, which may be responsible for functional limitations of the hip operated on. Preventive treatment may be carried out with radiation or drug therapy. The authors report the results of 54 cases submitted to prosthetic reimplantation and treated by cobalt therapy, as compared to the results of 76 reimplantations (control group) that did not undergo any kind of treatment: the occurrence of high grade ossification (exceeding Brooker grade III) was 2% in cases treated, as compared to 9% in those not treated. Males were more at risk for the development of ossification.

Diastematomyelia in congenital scoliosis. A review of the literature and description of one clinical case.

The authors present a case of diastematomyelia, a malformation of the neurospinal axis, frequently associated with congenital vertebral deformities. Often asymptomatic, its site different from that of the vertebral deformity, it may go unrecognized if specific imaging diagnosis is not used, thus exposing the patient who is then submitted to surgery for the correction of vertebral deformity to a high risk of neurological complications.

The use of cobalt therapy to prevent heterotopic ossification after total hip arthroplasty.

The occurrence of heterotopic ossification after total hip arthroplasty may be prevented by radiation or medical therapy. The authors report the results obtained in 96 cases treated by cobalt therapy: the occurrence of high grade ossification (Brooker III and IV) is equal to 1% in cases treated, as compared to 9% in cases not treated. Male patients of advanced age and who are characterized by primary arthrosis are more at risk for ossification.

The use of ceramic in prosthetic hip surgery. The state of the art.

The authors review current knowledge regarding the use of ceramic materials in prosthetic hip surgery, both as constituents of prosthetic components, and as materials used to coat metallic surfaces. A review of the literature defines the advantages and disadvantages to using ceramic-polyethylene or ceramic-ceramic combinations, based on the possibility that alumina coating may favor localized bone demineralization, and on the first promising clinical results of the use of hydroxyapatite coating.

Indications for prosthetic reimplantation.

It is difficult to establish on the basis of rigorous criteria when a prosthetic implant must be considered loosened, but it is even more difficult to define with certainty whether a loosened prosthesis must be reimplanted, and particularly when it is necessary to act. The authors emphasize the need to act quickly every time there is loss of periprosthetic bone substance that progresses in time, and that may make anatomical reconstruction difficult.

Which length for the revision stem?

The results of 79 stem implantations performed between 1981 and 1992 are presented. Mean clinical and radiographic follow-up was obtained 36 months after surgery. All of the prostheses were substituted due to aseptic loosening: of these 68% were cemented. Femoral osteolytic lesions secondary to loosening was classified based on the Paprosky protocol. A severe femoral osteolytic defect (type 2b, 2c or 3 according to Paprosky) was associated with 4% of the cases of loosened cementless prostheses, and with 37% of the cemented ones. Homoplastic bone grafts were used in 40% of the patients. The length of the stems used for reimplantation was short (12-13 cm) in 43%, standard (17-18 cm) in 49%, and long (> or = 22 cm) in 7% of the cases. These stems were cemented in 32% of the cases. The incidence of cementation was different in relation to length, as 62.5% of the short stems were cemented, as compared to 5.3% of the stems of standard length. Clinical results were excellent in 90% of the cases submitted to surgery with short stems, in 80% of those treated with standard stems, and in 50% of the cases of revision surgery where long stems were used. Radiographically, 97% of the short stems were osteointegrated, as compared to 94% of the standard stems and to 25% of the long ones, which were only used in a very few cases to be considered quite complex ones.

Techniques for removal of the stem: transfemoral or intramedullary?

Since 1981 a total of 76 reimplantations of the prosthetic stem have been performed, substituting 52 cemented stems and 24 cementless ones. Only 7 patients (9%) required transcortical access, 3 of these stems (43%) were not osteointegrated, while of the 69 reimplantations performed by intramedullary approach, only 4% of the stems did not achieve skeletal stabilization. A total of 43% of the stems reimplanted using an intramedullary approach were short (12-13 cm). The advantages of intramedullary access may be summarized by saying that diaphyseal cortical bone is saved; in the use of short prosthetic models. The transcortical technique is limited to a minority of patients, particularly to cases where stems that show osteointegration and are cementless are removed.

Orthopaedic manifestations of leukemia during childhood: a rare case of isolated periosteal reaction.

The authors describe one case of acute lymphoid leukemia during childhood manifested by migrant arthralgias. The only radiographic signs were constituted by a periosteal reaction in the left fibula. The main clinical symptoms and radiographic signs described in the literature and used to diagnose leukemia are reported.

Femoral bone remodeling: clinical experience with cemented and cementless total hip arthroplasty.

A radiographic study of femoral bone tissue remodeling around hip arthroplasty was carried out simultaneously in two series totalling 224 cementless and 77 cemented prostheses. Remodeling was analyzed by detailed visual evaluation of the radiographic assessment. The results show that the phenomenon of bone remodeling is still evolving more than 5 years after surgery. Bone demineralization of the proximal femur is more evident in cementless prostheses than in those stabilized with acrylic cement (24% vs. 12%). The preoperative state of mineralization significantly influences bone remodeling.