Biomedical subjects
Publications and source records attributed to S Terzi.
The authors describe a clinical case of a patient affected with Lowe syndrome. Ocular modifications, as well as those involving the nervous system, renal function, and the locomotor apparatus, typical of the syndrome, are taken into consideration. The problem of axial deformity of the knee, secondary to spontaneous fracture of the femur, a frequent occurrence in these patients, is dealt with.
Between November 1985 and October 1993, a total of 694 ceramic-ceramic hip arthroplasties were implanted; up until 1987 the alumina used in the first 82 cases was Ostalox, produced by IMEC of Caravaggio, characterized by poor control of the size of the crystals; after 1987 Biolox alumina of the Feldmhule company was used in 612 cases. Fracture of the ceramic head occurred in 2 cases; in both patients ceramic was of the Ostalox type, meaning a 2.4% incidence of fracture; up until the present none of the 612 Biolox heads has presented this complication.
Problems related to the use of total hip arthroplasty and the properties of the materials used to make prostheses have encouraged wear phenomena of the epiphysis-acetabulum combination of international importance and acknowledgement. Based on a review of the literature, the authors analyze the most recent years of study of wear phenomena and discuss the choice of materials to be used in total hip arthroplasty implant, with particular interest in any potential defects.
The authors report the radiographic results of 65 An. C.A. prosthetic stems coated with hydroxyapatite and followed-up at least 24 months after implantation. A comparison with a homogeneous group of aluminum-coated An.C.A. stems showed that hydroxyapatite-coated stems are characterized by better osteointegration, with a clearly inferior incidence of radiolucent lines at the bone/prosthesis interface. Macroscopic observation and histologic examination carried out on two stems removed because of persistent pain to the thigh revealed partial resorption and fragmentation of the coating. The authors believe that this phenomenon, the object of other observations reported in the literature, may indicate the reduced stability of the coating in the long run, and as such further in-depth study is required.
The authors report the results of 54 primary hip arthroplasty implants performed in patients aged over 75 years. The cases examined demonstrated that this type of surgery is not contraindicated in elderly patients as the occurrence of complications and perioperative risks are not higher if compared with a "younger" population. Preoperative anesthesiological evaluation that is extremely accurate is required.
A total of 19 cases of intraoperative fractures of the femoral diaphysis occurring during prosthetic hip reimplantation are described. Incidence, predisposing factors, treatment, and influence on long-term results are discussed. The pre-existence of osteolysis or narrowing of the femoral cortex, often associated with primary cemented implantation with a metal-polyethylene combination, constitutes a factor that predisposes the patient to fracture. Fracture consolidation occurs in most cases with minimum treatment, at times without instrumentation; fracture, however, always means a delay in weight-bearing and a slowing down in recovery times. Long-term clinical evaluation shows functional results that are worse for reimplantations complicated by fracture as compared to those where there are no complications. The differences in the radiographic results instead do not reveal statistical significance.
Testing conducted on a hip joint simulator verified the Charnley hypothesis that the diameter of the prosthetic head is proportional to wear. The study was conducted by pairing heads in Ortinox TM with acetabular cups in polyethylene at high molecular weight (UHMWPE). A comparison between the different sizes of the heads (26 and 30 mm in diameter) showed a different trend in the wear rate; in particular, the head with a smaller diameter behaves better tribologically than the head with a larger diameter.