Obesity does not influence acetabular component accuracy when using a 3D optical computer navigation system

INTRODUCTION

Improper cup positioning and leg length discrepancy (LLD) are two of the most common errors following total hip arthroplasty (THA) and are associated with potentially significant consequences. Obesity is associated with increased risk of mechanical complications, including dislocations, which may be secondary to cup malposition and failure to restore leg length and offset. 3D Optical Camera computerassisted navigation (CAN) system may reduce the risk of component malposition and LLD with real time intraoperative feedback. The aim of this study was to investigate whether the use of CAN influences acetabular component placement (CP) accuracy and leg length restoration in obese (body mass index(BMI)≥35kg/m 2 ) patients undergoing primary THA.

METHODS

A multi-center retrospective review was conducted identifying consecutive THA cases with BMI > 35kg/m 2 using CAN (Intellijoint Hip, Waterloo, CA) from 2015-2019. These patients were then matched with patients undergoing conventional THA (control) at a 1:1 ratio according to BMI, American Society of Anesthesiologists score, and gender. TraumaCad™ software (Brainlab, Chicago, IL) was used to measure cup anteversion, inclination, and change (Δ) in LLD between pre- and postoperative radiographic images. The safety target zones used as reference for precision analysis of CP were 15°-30° for anteversion and 30°-50° for inclination.

RESULTS

176 patients were included: 88 CAN and 88 control cases. CAN cases were found to have a lower ΔLLD than controls (3.53±2.12mm vs. 5.00±4.05mm; p=0.003). Additionally, more CAN cases fell within the target safe zone than controls (83% vs.60%, p=0.00083).

CONCLUSION

Our findings suggest that the use of a CAN system may be more precise in component placement, and useful in facilitating the successful restoration of preoperative leg length following THA than conventional methodology.

Evidence-based Review of Periarticular Injections and Peripheral Nerve Blocks in Total Knee Arthroplasty

Background:

Recently, post-operative pain management after Total Knee Arthroplasty (TKA) has focused on a multimodal approach for reducing opioid requirements, promoting early rehabilitation, and expediting discharge from hospital. Regional anesthesia, in the form of Periarticular Injections (PAI) and Peripheral Nerve Blocks (PNB), has shown promise as adjunctive therapy to oral analgesics.

Objective:

To review the current literature surrounding regional anesthesia for TKA.

Discussion:

PNBs provide effective analgesia after TKA. Historically, femoral nerve blocks (FNB) have been commonly employed. FNBs, however, lead to the significant motor blockade to the quadriceps musculature, which can dampen early rehabilitation efforts and increase the risk of post-operative falls. Adductor Canal Blocks (ACB) have shown excellent results in reducing post-operative pain while minimizing motor blockade. Periarticular injections (PAI), and infiltration between the popliteal Artery and Capsule of the Knee (IPACK) have similarly helped in reducing patient discomfort after TKA and providing analgesia to the posterior capsular region of the knee.

Conclusion:

PAIs, and PNBs are important elements in many multimodal postoperative pain management protocols after TKA. Current evidence appears to suggest that a combination of an ACB supplemented by posterior capsular analgesic coverage through PAI or IPACK may provide optimal results.

Impaired dopaminergic neurotransmission and microtubule-associated protein tau alterations in human LRRK2 transgenic mice

Mutations in the Leucine Rich Repeat Kinase 2 (LRRK2) gene, first described in 2004 have now emerged as the most important genetic finding in both autosomal dominant and sporadic Parkinson's disease (PD). While a formidable research effort has ensued since the initial gene discovery, little is known of either the normal or the pathological role of LRRK2. We have created lines of mice that express human wild-type (hWT) or G2019S Lrrk2 via bacterial artificial chromosome (BAC) transgenesis. In vivo analysis of the dopaminergic system revealed abnormal dopamine neurotransmission in both hWT and G2019S transgenic mice evidenced by a decrease in extra-cellular dopamine levels, which was detected without pharmacological manipulation. Immunopathological analysis revealed changes in localization and increased phosphorylation of microtubule binding protein tau in G2019S mice. Quantitative biochemical analysis confirmed the presence of differential phospho-tau species in G2019S mice but surprisingly, upon dephosphorylation the tau isoform banding pattern in G2019S mice remained altered. This suggests that other post-translational modifications of tau occur in G2019S mice. We hypothesize that Lrrk2 may impact on tau processing which subsequently leads to increased phosphorylation. Our models will be useful for further understanding of the mechanistic actions of LRRK2 and future therapeutic screening.