A cadaveric model to evaluate the effect of unloading the medial quadriceps on patellar tracking and patellofemoral joint pressure and stability

Background Vastus Medialis Muscles (VMM) damage has been widely identified following patellar dislocation. Rehabilitation programmes have been suggested to strengthen the VMM and reduce clinical symptoms of pain and instability. This controlled laboratory study investigated the hypothesis that reduced Vastus Medialis Obliquus (VMO) and Vastus Medialis Longus (VML) muscle tension would alter patellar tracking, stability and PFJ contact pressures. Methods Nine fresh-frozen dissected cadaveric knees were mounted in a rig with the quadriceps and iliotibial band loaded to 205 N. An optical tracking system measured joint kinematics and pressure sensitive film between the patella and trochlea measured PFJ contact pressures. Measurements were repeated for three conditions: 1. With all quadriceps heads and iliotibial band (ITB) loaded; 2. as 1, but with the VMO muscle unloaded and 3. as 1, but with the VMO and VML unloaded. Measurements were also repeated for the three conditions with a 10 N lateral displacement force applied to the patella. Results Reduction of VMM tension resulted in significant increases in lateral patellar tilt (2.8°) and translation (4 mm), with elevated lateral and reduced medial joint contact pressures from 0.48 to 0.14 MPa, and reduced patellar stability (all p < 0.05). Conclusions These findings provide basic scientific rationale to support the role of quadriceps strengthening to resist patellar lateral maltracking and rebalance the articular contact pressure away from the lateral facet in patients with normal patellofemoral joint anatomy

The changing patterns of access overtime to the renal replacement therapy programme in Thailand.

Based on projected numbers, approximately only 50% of those requiring renal replacement therapy (RRT) receive it. Many patients who require RRT live in low- and middle-income countries. The objective of this study was to examine the changing pattern over time of entry into the RRT programme in Thailand following RRT's inclusion in the Universal Coverage Scheme. This study was an ecological study using the age-period-cohort analysis to look at dialysis registration and kidney transplant trends during RRT programme implementation. Data from 2008 to 2016 of patients diagnosed with end-stage renal disease (ESRD) were obtained from the National Health Security Office. The study found that the numbers of new patients with ESRD, aged 20-69, registered with the dialysis programme increased over time. For patients aged 20-40 years, the dialysis programme took up to 400 new patients for every 1000 new ESRD diagnoses. For kidney transplant, the rates increased slowly. The kidney transplant programme could at best treat only around 50 cases for every 1000 new ESRD diagnoses in patients aged 20-30 years. Findings of this study highlighted the importance of promoting strategies to reduce the increasing number of patients with kidney disease, to consider conservative therapy for older/frail patients, and to improve access to kidney transplantation and live-donation

What parathyroid hormone levels should we aim for in children with stage 5 chronic kidney disease; what is the evidence?

The bone disease that occurs as a result of chronic kidney disease (CKD) is not only debilitating but also linked to poor growth and cardiovascular disease. It is suspected that abnormal bone turnover is the main culprit for these poor outcomes. Plasma parathyroid hormone (PTH) levels are used as a surrogate marker of bone turnover, and there is a small number of studies in children that have attempted to identify the range of PTH levels that correlates with normal bone histology. It is clear that high PTH levels are associated with high bone turnover, although the range is wide. However, the ability of PTH levels to distinguish between low and normal bone turnover is less clear. This is an important issue, because current guidelines for calcium and phosphate management are based upon there being an “optimum” range for PTH. This editorial takes a critical look at the evidence upon which these recommendations are based

Patellofemoral joint biomechanics: computational modelling and clinical applications

The patellofemoral joint (PFJ) plays an important role in the extensor mechanism of the knee. Several types of PFJ disorders are commonly found in about 25% of the people. It is believed that patellofemoral (PF) disorders, e.g. excessive lateral pressure syndrome and patellar maltracking, may be associated with articular cartilage contact pressure elevation, which accelerates degenerative joint disease and causes anterior knee pain. To reduce the pressures, a number of anatomical interventions have been applied to correct contact mechanics and patellar tracking. However, the rate of successful surgery is not high because the anatomical complexity of the joint itself and complex symptoms make diagnosis difficult. For this reason, various computational modelling techniques have been developed to assist in diagnosis and prognosis of PF disorders. This research aims to develop a finite element (FE) modelling method and study the feasibility of its clinical applications. The modelling methods may assist in the diagnostic and treatment planning processes. The research was divided into five phases: 1) development of an FE modelling method to analyse PFJ models 2) model validation using in vitro experimental data 3) development of subject-specific input estimation method from routine diagnosis protocols 4) model sensitivity analysis and 5) clinical applications. The FE results included joint contact force, contact pressure, subchondral bone stress and patellar kinematics. The validation and sensitivity analysis showed that the FE modelling method could adequately analyse PFJ biomechanics. Approval for a clinical study was obtained from the National Health Service (NHS) Research Ethics Committee, and groups of control subjects, anterior knee pain (AKP) patients and those with trochlear dysplasia and trochleoplasty were recruited. The modelling method was applied to analyse their knees and predict their non-operative and operative treatment outcomes. The study showed that the biomechanical responses of the PFJ and the treatment evaluations were variable. In particular, it was found that AKP was associated with significant elevation of contact pressure; thus confirming the usefulness of the FE modelling method as a powerful diagnostic and surgical planning tool for subject-specific PFJ treatment.Open Acces

Impact of acute kidney injury and renal recovery status in deceased donor to kidney transplant outcome: results from the Thai national transplant registry

Abstract The influence of acute kidney injury (AKI) and renal recovery in deceased donor (DD) on long-term kidney transplant (KT) outcome has not previously been elucidated in large registry study. Our retrospective cohort study included all DDKT performed in Thailand between 2001 and 2018. Donor data was reviewed case by case. AKI was diagnosed according to the KDIGO criteria. Renal recovery was defined if DD had an improvement in AKI to the normal or lower stage. All outcomes were determined until the end of 2020. This study enrolled 4234 KT recipients from 2198 DD. The KDIGO staging of AKI was as follows: stage 1 for 710 donors (32.3%), stage 2 for 490 donors (22.3%) and stage 3 for 342 donors (15.6%). AKI was partial and complete recovery in 265 (17.2%) and 287 (18.6%) before procurement, respectively. Persistent AKI was revealed in 1906 KT of 990 (45%) DD. The ongoing AKI in DD significantly increases the risk of DGF development in the adjusted model (HR 1.69; 95% CI 1.44–1.99; p < 0.001). KT from DD with AKI and partial/complete recovery was associated with a lower risk of transplant loss (log-rank P = 0.04) and recipient mortality (log-rank P = 0.042) than ongoing AKI. KT from a donor with ongoing stage 3 AKI was associated with a higher risk of all-cause graft loss (HR 1.8; 95% CI 1.12–2.88; p = 0.02) and mortality (HR 2.19; 95% CI 1.09–4.41; p = 0.03) than stage 3 AKI with renal recovery. Persistent AKI, but not recovered AKI, significantly increases the risk of DGF. Utilizing kidneys from donors with improving AKI is generally safe. KT from donors with persistent AKI stage 3 results in a higher risk of transplant failure and recipient mortality. Therefore, meticulous pretransplant evaluation of such kidneys and intensive surveillance after KT is recommended