Shock wave lithotripsy, for the treatment of kidney stones, results in changes to routine blood tests and novel biomarkers: a prospective clinical pilot-study.

BACKGROUND: The number of patients undergoing shock wave lithotripsy (SWL) for kidney stones is increasing annually, and as such the development of post-operative complications, such as haematuria and acute kidney injury (AKI) following SWL, is likely to increase. The aim of the study was to evaluate changes in routine blood and novel biomarkers following SWL, for the treatment of kidney stones. METHODS: Twelve patients undergoing SWL for solitary unilateral kidney stones were recruited. From patients (8 males and 4 females) aged between 31 and 72 years (median 43 years), venous blood samples were collected pre-operatively (baseline), at 30, 120 and 240 min post-operatively. Routine blood tests were performed using a Sysmex XE-5000, and Beckman Coulter AU5800 and AU680 analysers. NGAL, IL-18, IL-6, TNF-α, IL-10 and IL-8 concentrations were determined using commercially available ELISA kits. RESULTS: Significant (p ≤ 0.05) changes were observed in several blood parameters following SWL. NGAL concentration significantly increased, with values peaking at 30 min post-treatment (p = 0.033). Although IL-18 concentration increased, these changes were not significant (p = 0.116). IL-6 revealed a statistically significant rise from pre-operative up to 4 h post-operatively (p < 0.001), whilst TNF-α significantly increased, peaking at 30 min post-SWL (p = 0.05). There were no significant changes to IL-10 and IL-8 concentrations post-SWL (p > 0.05). CONCLUSIONS: Changes to routine blood tests and specific biomarkers, in the future, may be more useful for clinicians. In turn, identification of a panel of biomarkers could provide valuable data on "normal" physiological response after lithotripsy. Ultimately, studies could be expanded to identify or predict those patients at increased risk of developing post-operative complications, such as acute kidney injury or. These studies, however, need validating involving larger cohorts.

The influence of tibial component malalignment on bone strain in revision total knee replacement.

Revision total knee replacement is a challenging surgical procedure typically associated with significant loss of bone stock in the proximal tibia. To increase the fixation stability, extended stems are frequently used for the tibial component in revision surgery. The design of the tibial stem influences the load transfer from tibial component to the surrounding bone and is cited as a possible cause for the clinically reported pain in the location of the stem-end. This study aimed to analyse the strain distribution of a fully cemented revision tibial component with a validated finite element model. The model was developed from a scanned composite tibia (Sawbones), with an implanted, fully cemented stemmed tibial component aligned to the mechanical axis of the tibia. Loading was applied to the tibial component with mediolateral compartment load distributions of 60:40 and 80:20. Three strain gauged composite tibias with implanted tibial components of the same design using the same loading distribution were tested to obtain experimental strains at five locations in the proximal tibia. The finite element model developed was validated against strain measurements obtained in the experimental study. The strains displayed similar patterns (R(2) = 0.988) and magnitudes with those predicted from the finite element model. The displacement of the stem-end from the natural mechanical axis in the finite element model demonstrated increased strains in the stem-end region with a close proximity of the distal stem with the cortical bone. The simulation of a mediolateral compartment load of 80:20 developed peak cortical strain values on the posterior-medial side beneath the stem. This may possibly be related to the clinically reported pain at the stem-end. Furthermore, stem positioning in close proximity or contact with the posterior cortical bone is a contributory factor for an increase in distal strain.

Strong correlation between the morphology of the proximal femur and the geometry of the distal femoral trochlea.

PURPOSE: Previous investigations suggested that the geometry of the proximal femur may be related to osteoarthritis of the tibiofemoral joint and various patellofemoral joint conditions. This study aims to investigate the correlation between proximal and distal femoral geometry. Such a correlation could aid our understanding of patient complications after total knee arthroplasty (TKA) and be of benefit for further development of kinematic approaches in TKA. METHODS: CT scans of 60 subjects (30 males, 30 females) were used to identify anatomical landmarks to calculate anatomical parameters of the femur, including the femoral neck anteversion angle, neck-shaft angle (NSA), mediolateral offset (ML-offset), condylar twist angle (CTA), trochlear sulcus angle (TSA) and medial/lateral trochlear inclination angles (MTIA/LTIA). Correlation analyses were carried out to assess the relationship between these parameters, and the effect of gender was investigated. RESULTS: The CTA, TSA and LTIA showed no correlation with any proximal parameter. The MTIA was correlated with all three proximal parameters, mostly with the NSA and ML-offset. Per 5° increase in NSA, the MTIA was 2.1° lower (p < 0.01), and for every 5 mm increase in ML-offset, there was a 2.6° increase in MTIA (p < 0.01). These results were strongest and statistically significant in females and not in males and were independent of length and weight. CONCLUSIONS: Proximal femoral geometry is distinctively linked with trochlear morphology. In order to improve knowledge on the physiological kinematics of the knee joint and to improve the concept of kinematic knee replacement, the proximal femur seems to be a factor of clinical importance. LEVEL OF EVIDENCE: III.