Over 62,000 total hip arthroplasty (THA) cases are performed each year in Canada, with an estimated annual healthcare system cost of $1.4 billion and resulting in 4 billion tonnes of waste annually (6,600 tonnes per day). The aims of this study were 1) Assess satisfaction of current/standard set-up amongst different stakeholders. 2) Assess energy, economic and waste cost of current set up and apply lean methodology to improve efficiency 3. Design and test SLIM setup based on lean principles and its ability to be safely implemented into everyday practice.

A Needs Assessment Survey was circulated to OR nursing staff to assess the need for change in the current THA OR setup at an academic tertiary referral hospital. Through feedback, surgeon input, and careful analysis of current instrumentation, the “SLIM setup” was created. Standard instrument tray numbers for elective THA were reduced from 9 to 3 trays. Eighty patients were then randomised to either the standard or SLIM setup. Four staff arthroplasty surgeons each randomised 20 patients to either standard or SLIM setup. OR time, blood loss, 90-day complication rates, cost/case, instrument weight (kg/case), total waste in kg/case (non-recyclable), case set-up time, and number of times and number of extra trays required were compared between groups.

The majority of nursing staff demonstrated dissatisfaction with the current THA setup and felt current processes lacked efficiency. Use of the SLIM setup, was associated with the following savings in comparison to standard (Trays = −6 (720kg/case); Waste = −1.5 kg/case; Cost = − $560 ($50.00 × 6 trays + 10min saved × $26.00 /min OR setup time)). OR time, blood loss and 90-day complication rate were not statistically different (p >0.05); however, set up time was significantly shorter in comparison to standard. Extra instrumentation was opened in < 10% of cases.

A more minimalist approach to THA can be undertaken using the SLIM setup, potentially resulting in cost, energy and waste savings. Estimate savings of $560,000 and 1.65 tonnes reduction in waste per 1,000 THAs performed may be realised.

This matched cohort study aims to (a) assess differences in spinopelvic characteristics of patients having sustained a dislocation following THA and a control THA group without dislocation; (b) identify spinopelvic characteristics associated with risk of dislocation and; (c) propose an algorithm to define the optimum cup orientation for minimizing dislocation risk.

Fifty patients with a history of THA dislocation (29 posterior-, 21 anterior dislocations) were matched for age, gender, body mass index, index diagnosis, and femoral head size with 100 controls. All patients were reviewed and underwent detailed quasi-static radiographic evaluations of the coronal- (offset; center-of-rotation; cup inclination/anteversion) and sagittal- reconstructions (pelvic tilt, pelvic incidence, lumbar lordosis, pelvic-femoral-angle, cup ante-inclination). The spinopelvic balance (PI-LL), combined sagittal index (CSI= Pelvic-femoral-angle + Cup Anteinclination) and Hip-User-Index were determined. sagittal index (CSI= Pelvic-femoral-angle + Cup Anteinclination) and Hip-User-Index were determined. Parameters were compared between the two groups (2-group analysis) and between controls and per direction of dislocation (3-group analysis).

There were marginal coronal differences between the groups. Sagittal parameters (lumbar-lordosis, pelvic-tilt, CSI, PI-LL and Hip-User-Index) differed significantly. PI-LL (>10°) and standing pelvic tilt (>18°) were the strongest predictors of dislocation risk (sensistivity:70%/specificity:70%). All hips with a standing CSI<195° dislocated posteriorly and all with CSI>260° dislocated anteriorly. A CSI between 200–245° was associated with significantly reduced risk of dislocation (OR:6; 95%CI:2.5–15.0; p<0.001). In patients with unbalanced and/or rigid lumbar spine, standing CSI of 215–245° was associated with significantly reduced dislocation risk (OR:10; 95%CI:3.2–29.8; p<0.001).

PI-LL and standing pelvic-tilt determined from pre-operative, standing, lateral spinopelvic radiograph can be useful screening tools, alerting surgeons of patients at increased dislocation risk. Measurement of the pelvic-femoral angle pre-operatively provides valuable information to determine the optimum, cup orientation associated with reduced dislocation risk by aiming for a standing CSI of 200–245°.