No abstract

We report the updated results for a previously evaluated patient cohort who had uncemented total hip arthroplasties using the Lord femoral component. The original cohort consisted of 114 total hip arthroplasties (110 patients) performed from 1979 to 1984. The patients were followed up for an average of 21 years postoperatively. We describe the radiographic findings of 57 hips. At the last followup 11 (9.6%) of the 114 femoral components were revised or removed. Excluding infection there was an 83% 21-year survival according to Kaplan-Meier analysis. No significant radiographic changes occurred since the last publication. The prostheses are very well-fixed with no signs of loosening. Our current findings show the durability of the uncemented Lord femoral component indicating this prosthesis provides good long-term results.

Patients being treated with interferon-β should have periodic fundus examinations to determine if they have evidence of interferon-associated retinopathy.

Purpose: To analyze and understand the zonular tension and distribution of forces in the presence of zonular disinsertion in a model simulation with and without a capsular tension ring (CTR). Methods: This study was conducted at Complejo Hospitalario Universitario Albacete, University of Castilla La Mancha, Spain. Twelve load cells were arranged in a circular fashion to simulate the 360 degrees of zonulae in the eye. An elastic band was prestretched in a uniform and radial manner in 12 directions. Force measurements were taken using 12 load cells, uniformly arranged at 30° spacing around the elastic band. Tension was measured at each cell, before and after the simulated zonulardisinsertion. Every clock hour of zonular disinsertion was cycled through all 12 load cells. The tension was evaluated for zonular disinsertion ranging from 0 to 5 clock hours (0° to 150°) with and without a CTR. Results: An increase in zonular tension was recorded in the load cells adjacent to the segments of zonular disinsertion. As the zonular disinsertion progressed, opposing forces could no longer cancel each other out, leading to a displacement of thecomplex. The use of a CTR redistributed the forces, providing better centration in the presence of zonulolysis. Conclusion: This study visualizes the distribution of forces and displacement of the capsular bag complex in the presence of zonular disinsertion and demonstrates a significant increase in zonular tension in the areas adjacent to the segment of zonular disinsertion. The use of a CTR managed to redistribute the tension over the remaining zonulae, maintaining better centration in the presence of zonulolysis. The knowledge of this behavior can help surgeons tackle clinically significant zonular disinsertion.

Purpose: To evaluate the resistance to compression of commercially available capsular tension rings (CTRs) when submitted "in vitro" to a constant pressure over a period of time.Setting: Research Unit. CHU Albacete. University of Castilla La Mancha. Spain.Method: Four samples of 3 different CTR manufacturers were evaluated for resistance to compression over time while being exposed to a constant tension. The 13 millimetres CTRs were placed in a round rigid container with an 11 millimetres diameter and submerged in BSS at body temperature (37 degrees Celsius). CTRs were divided into two groups. Two samples of each model were introduced in the containers and removed and evaluated at 1 month, while the other two samples of each model were introduced in the containers and removed and evaluated at three months. Size and shape of the CTRs were measured at baseline, at 1 month and 3 months. Every measurement was repeated 3 times by two different observers. Results:The mean decrease in CTRs diameter of the 1 month compression group was 1, 5 millimetres. The mean decrease in CTRs diameter of the 3 month compression group was 1, 63 millimetres. The differences in diameter between baseline and 1 month, as well as baseline and 3 months were statistically significant. There was no statistical significance when comparing the final size between the 1 month and 3 months groups. Conclusion:All the commercially available CTRs studied have shown a decrease in diameter when exposed to a constant compression at body temperature. This could explain some of the published reports of capsular bag shrinkage or even dislocation of the entire IOL-CTR complex despite the implantation of a CTR.

Introduction: The biocompatibility of nitinol in the human body has extensively been demonstrated. Although nitinol is already being used for intraocular surgeries such as lens fragmentation and foreign body extraction, little is known about its intracapsular, long-term behavior. The purpose of this study is to evaluate the long-term uveal and capsular biocompatibility of a nitinol CTR placed in the capsular bag after cataract surgery in an animal model. Method: After approval of the study by the Institutional Animal Care and the Ethics Committee, bilateral phacoemulsification was performed in 6 rabbits; 1 eye received a nitinol CTR and the other a control polymethylmethacrylate (PMMA) open-ended ring. Ophthalmic evaluation for the presence of infections in all 12 eyes was performed after 7 days, 4 weeks, 3 months, and 6 months follow-up period. After a follow-up period of 6 months, the eyes were enucleated, and a histopathologic evaluation was performed. Results: Neither of the groups showed any clinical signs of posterior capsule opacification (PCO) or inflammation. The nitinol group showed slightly less inflammation during histopathologic examination compared to the PMMA group. No biocompatibility issues have been observed in this animal study. Conclusions: There were no histological differences between eyes implanted with nitinol and eyes implanted with PMMA rings. Nitinol has proven to show high biocompatibility when implanted in the capsular bag of the rabbit eye.