Introduction

Little guidance exists regarding the minimum screw length and number necessary to achieve fixation with reverse shoulder arthroplasty (rTSA). The goal of this study is to quantify the pre- and post-cyclic baseplate displacements associated with two baseplate designs of different sizes using multiple screw lengths and numbers in a low density polyurethane bone substitute model.

Aim of study (background): Probability of survival (Ps) is calculated presently by using the TRISS methodology for trauma patients. This utilises physiological scoring parameters, injury scoring system and the patient age. The physiological parameters need to be recorded for determining the RTS, but this data is often missed. The aim of our study was to assess how the essential variables correlate with the Ps and if any other variables contribute significantly to the Ps. Depending on the correlation of any new variables, is it time to change the formula for calculating Ps?

Material and methods: A retrospective study was carried out involving 678 trauma patients. The ISS and RTS scores were calculated from the trauma charts. The relationship between ISS, RTS, age and GCS with Ps was assessed using the correlation and regression analysis and then the affect of gender on Ps was assessed using a T test.

Results: ISS of trauma victims had a mean of 10.22. The results showed a strong negative correlation between ISS and Ps with an r value of −0.633 (p< 0.005). GCS correlated strongly with Ps, with an r value of 0.733 (p< 0.005). In the regression analysis; ISS and GCS showed a strong correlation with Ps. RTS made the weakest contribution to Ps, followed by age. GCS made the strongest unique contribution. There also no significant difference in the mean scores of Ps for males and females (p< 0.005).

Conclusion: The results indicated significantly strong correlations between ISS and GCS with Ps. There was a poor correlation between RTS and Ps. This is helpful for the patients in whom RTS scores cannot be calculated, as GCS can be used in place of RTS. There may be a need for a new system to calculate Ps using GCS and gender.

A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release.

In a prospective randomized study (ABC), 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. A fourth arm (Trident) was included involving use of a metal-backed acetabular component implanted in 209 patients.

At a mean follow-up of 35.2 months (range, 24–48 months), there was no significant difference in clinical performance between the patient cohorts. The cohort of patients included in the ABC, Trident, and extended access portion of the study represents a population of 2313 patients with no device related failures attributable to the ceramic on ceramic articulation used in these patients

This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients.