The use of navigation to achieve soft tissue balance in total knee arthroplasty - a randomised clinical study

BACKGROUND

Achieving soft tissue balance is an operative goal in total knee arthroplasty. This randomised, prospective study compared computer navigation to conventional techniques in achieving soft tissue balance.

METHODS

Forty one consecutive knee arthroplasties were randomised to either a non-navigated or navigated group. In the non-navigated group, balancing was carried out using surgeon judgement. In the navigated group, balancing was carried out using navigation software. In both groups, the navigation software was used as a measuring tool.

RESULTS

Balancing of the mediolateral extension gap was superior in the navigation group (p=0.001). No significant difference was found between the two groups in balancing the mediolateral flexion gap or in achieving equal flexion and extension gaps.

CONCLUSIONS

Computer navigation offered little advantage over experienced surgeon judgement in achieving soft tissue balance in knee replacement. However, the method employed in the navigated group did provide a reproducible and objective assessment of flexion and extension gaps and may therefore benefit surgeons in training.

LEVEL OF EVIDENCE

Level I, RCT.

Adverse myocardial effects of B-vitamin therapy in subjects with chronic kidney disease and hyperhomocysteinaemia

BACKGROUND & AIMS

Hyperhomocysteinaemia (HHCY), a common finding in patients with chronic kidney disease (CKD), has been shown to contribute to adverse cardiac remodelling and failure. We hypothesised that in human subjects with CKD, HHCY would be associated with myocardial dysfunction, and that homocysteine (HCY)-lowering therapy would improve myocardial remodelling and heart-failure (HF) outcomes.

METHODS AND RESULTS

Post hoc analysis of the Homocysteinemia in Kidney and End Stage Renal Disease (HOST) trial (n=2056) was performed to determine if HCY-lowering therapy with high dose B vitamins affects HF outcomes in patients with CKD. In addition, effects on myocardial remodelling were assessed in a subgroup of 220 trial subjects who had transthoracic echocardiograms done before study randomisation and during the course of the study as part of their routine clinical care. HF outcomes were not significantly affected by treatment compared to the placebo. HCY levels were inversely correlated with diastolic function (R=-0.21; p=0.038). Vitamin therapy resulted in a significant increase in left atrial size (+0.15±0.8 cm vs. -0.13±0.07 cm; p=0.0095). No other echocardiographic parameters were significantly associated with baseline HCY levels or changes with vitamin therapy.

CONCLUSION

HHCY is associated with diastolic dysfunction in patients with CKD. However, B-vitamin therapy did not improve HF outcomes despite lowering of plasma HCY levels, and was associated with an increase in left atrial size, which is a surrogate for worsening left ventricular diastolic dysfunction. These findings suggest that high-dose B vitamin therapy may be harmful in patients with CKD.

Extension MRI is clinically useful in cervical myelopathy

INTRODUCTION

Cervical spine MRI with the neck in extension has been well described over the last 10 years, but its clinical value remains unknown.

METHODS

We performed extension imaging in 60 patients in whom the initial neutral study showed borderline cord compression. Images were assessed using a previously validated grading system for cord compression. Multiple linear and area measurements were also obtained. Images were scored blindly and randomly. Inter- and intra-rater variability were determined in a subset of 20 cases. Independent clinical assessment utilised the Ranwat criteria.

RESULTS

For most parameters inter/intra-observer variance of kappa/ICC > 0.6 was highly satisfactory. Standard MR was poor at discriminating between patients with and without myelopathy (ROC analysis, area under the curve (AUC), 0.52). This was considerably improved with extension imaging (AUC, 0.60), or by using the change in compression score between neutral and extension studies. Most measurements were not helpful; however, the ratio of cord area/CSF area at the level of maximum compression on extended images was the best discriminator (AUC, 0.71), as well as the presence of T2 change in cord substance (AUC, 0.68).

CONCLUSION

This is the first study to demonstrate added clinical value utilising extension MRI. In this cohort of difficult patients, when there was no T2 signal change in the cord, the presence of clinical myelopathy could only be predicted by utilising the data from extension imaging.

The use of bortezomib as a rescue treatment for acute antibody-mediated rejection: report of three cases and review of literature

Antibody-mediated rejection (AMR) typically occurs early after transplantation in approximately 5%-7% of recipients. The literature reports suggest that 12%-37% of kidney transplant recipients with acute AMR do not respond to treatment and eventually lose their grafts. The proteasome inhibitor bortezomib is currently approved by the Food and Drug Administration for the treatment of multiple myeloma. It has been demonstrated both in vitro and in vivo to possess apoptotic properties against mature plasma cells. Herein we have described a series of 3 patients with positive cross-matches who developed early AMR after kidney transplantation. Bortezomib rescue treatment was administered after the patients failed to respond to plasmapheresis/intravenous immunoglobulin and splenectomy. All 3 patients responded with full, durable recovery of renal function. In conclusion, bortezomib is useful to treat refractory AMR after kidney transplantation.

Abstract P6-04-12: Novel selective estrogen receptors degraders regress tumors in pre-clinical models of endocrine-resistant breast cancer

80% of all breast cancers express the estrogen receptor alpha (ERα) and thus are treated with anti-hormonal therapies that directly block ER function (e.g. Tamoxifen) or hormone synthesis (Aromatase Inhibitors). While these therapies are initially effective, acquired resistance invariably emerges. Importantly, the majority of these tumors continue to depend on ERα for growth and survival. The emerging evidence that ERα can signal in both a ligand-dependent and ligand-independent manner supports the development of agents that are not only competitive ERα antagonists but also reduce steady state levels of the receptor and thus limit both modes of signaling.

We have identified novel, non-steroidal ERα antagonists that induce degradation of ERα in breast cancer cell lines at picomolar concentrations resulting in significant reduction in steady state ERα protein levels. Using peptide-based conformational profiling, we show that these Selective Estrogen Receptor Degraders (SERDs) induce estrogen receptor conformations that are distinct from both fulvestrant and tamoxifen indicating a unique mechanism of action. This unique biological profile coupled with good oral pharmacokinetics produces tumor regressions in both tamoxifen-sensitive and -resistant models of breast cancer in vivo. Recent pre-clinical and clinical data indicate that PI3K pathway signaling can contribute to the endocrine resistant state. In a preclinical model of tamoxifen resistant breast cancer in which SERD monotherapy only produces tumor growth inhibition, SERD therapy in combination with torc1/2 inhibition results in frank tumor regressions. These orally bioavailable SERDs hold promise as a next generation therapy for the treatment of ER+ breast cancer as monotherapy, as well as in combination with agents that target other pathways involved in both intrinsic and acquired endocrine resistance.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P6-04-12.