The implantation of Total Hip Replacements (THR) has become the standard treatment for advanced osteoarthritis of this joint. Since the first articular replacements using monopolar components, hardware has been improving from cemented to porous coated noncemented implants and more recently hydroxyapatite coated (HAC) prosthesis. We started using HAC replacements in 1989 and we have been increasingly using these implants since then, even expanding its indications.

From 1989 to 1999 we have implanted 140 THR using a HAC model. The clinical records and X-rays of these patients were reviewed 5 to 15 years after the implantation of the primary prosthesis.

Results: The average age at surgery was 61.71 years, ranging from 18.7 to 83.5. At an average follow up of 9.17 years, 21 of them required a revision. In two cases both the stem and cup were replaced and in 19 only the acetabular cup was replaced.

This yields a survival rate of 85% and a revision rate of 15% for cups after an average of 9.17 years and a survival rate of 98.57% and revision rate of 1.43 for femoral stems. The revision was done at an average of 1.37 years when femoral components were involved (in 2 cases) and 6.79 for isolated acetabular components (in 19 cases). The overall survival of the revised prosthesis would have been 6.28 years. The main cause for revision was related to acetabular loosening and polyethylene wear in 18 cases, 2 for component malposition and one for infection.

Discussion and conclusions: Our results show that HAC THR offer a good long and mid term survival rate. However, the design of the acetabular component and polyethylene need further investigation to improve fixation to bone and wear resistance, respectively.

Aim: Evaluate the preoperative prognostic factors of a poor result in conventional surgery of lumbar disc herniation. Methods: From November 1995 to November 2001, we performed 113 standard discectomies (63 males/50 females) with a mean-age of 42 years (21–75). All patients had been evaluated preoperatively with X-ray and C.T. scan. Fifty-nine patients (52%) had a preoperative M.R.I., and an evaluation was made of disk degeneration degree, multilevel degeneration and bone changes in vertebral end-plates (according Modic classiþcation). The postoperative mean follow-up was 46,2 months. The outcomes were evaluated considering the reoperation rate, the intensity of pain in the Visual Analogue Score, and þnal function with the Oswestry Disability Index. The results were compared using ANOVA. Results: We have found a statistical correlation between a poor result and older age (p=0.006), diabetes (p=0.005), psychological factors (p=0.006) and preoperative X-ray changes, such as disk height loss greater than a third (p< 0.001), subcondral sclerosis (p< 0.001), segmental instability (p=0.019) and ostheo-arthritis (p< 0.001). Regarding M.R.I., the multilevel degeneration and the Modic changes (type I, II or III) have been correlated in this study with poor functional result (p=0.004 and p< 0.001 respectively). Conclusions: Our results support the concept that in patients with lumbar disk herniation and with described X-ray or M.R.I. changes, especially changes in vertebral end-plate, we should strongly consider treatment for disk degeneration and not limit the intervention to the excision of disk extrusion.