Aim

Biomechanical models of the shoulder have been used to measure forces and glenohumeral pressures. Their results have been found to vary. The aim of this study was to produce a biomechanical model to replicate the biomechanical principles of the glenohumeral joint and to measure the centre of pressure on the glenoid through a mid-range of arm movement with an intact and a compromised rotator cuff.

Antibiotic bone cement as a form of prophylaxis against deep infection for total hip joint replacements is widely used; however its efficacy has not been proven. This study aims to determine if the use of prophylactic antibiotic cement for primary total hip joint replacements in New Zealand reduces the risk of deep infection requiring revision.

Data from January 1999 to December 2007 were recovered from the New Zealand National Joint Registry. Proportional hazards regression analysis was used to study the relative revision risks or failure rates between those THJR which utilised antibiotic bone cement and those using plain bone cement.

Of the 32,646 hips included in the study 1376 were revised. The overall use of antibiotic and plain cement through this time period is relatively equal, with 18,863 (54.7%) receiving ABC compared to 16,295 (46.3%) hips receiving plain cement. The presence of antibiotics in bone cement was not found to affect whether the hip went on to get revised for deep infection (p =0.16). Nor was the type of operating theatre (p=0.13), the use of space suits (p=0.97), and the operative time (p=0.55). Younger age was found to be the most significant indicator for the need for revision for infection (p value 0.00014).

The induction of antibiotic resistance and the significant additional costs associated with antibiotic bone cement cannot be denied. While the literature supports the prophylactic use of antibiotic bone cement for patients at high risk of infection, the routine use in patients who have a low risk of infection may not be justified.