553 Does Patella Implant Design Affect Outcomes? Patella Resurfacing in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

Aim

To investigate whether implant design affect (1)incidence of anterior knee pain, (2)patient reported outcomes and (3)reintervention rates in a resurfaced vs non-resurfaced Total Knee Arthroplasty (TKA).

Method

MEDline, pubmed and google scholar studies were evaluated using SIGN assessment tool and data analysis was conducted using Review Manager 5.2 on only randomised controlled trials. Search terms: arthroplasty, replacement, knee (Mesh), TKA, prosthesis, patella, patellar resurfacing, patellar retaining.

Results

33 randomised controlled studies were identified. A total of 11 used the modern “patella-friendly” implants and 22 used the older “patella non-friendly” implants.

There was no significant difference in anterior knee pain rates for either surgical option. When using patella-friendly implant, patella resurfacing results in a statistically higher clinical (P 0.007, MD -0.77) and functional (P < 0.0001, MD -1.87) KSS than the non-resurfaced counterparts, but scores were not clinically significant. When the patella was not resurfaced, there was a significant increased risk of reoperation with “non-patella friendly” implant (p=0.04, OR 1.42, CI 1.01, 2.00), whilst there was no significant difference between reoperation rates for the “patella friendly” implants (OR 1.17, CI 0.59,2.30).

Conclusions

Patella implant design has been shown to significantly improve KSS scores but with no clinical significance. Risk of further procedures was significantly higher in non-resurfaced patella TKAs with “non-friendly” implants, likely due to increased rates of anterior knee pain in these older generation implants leading to secondary resurfacing. However, when utilising “patella-friendly” implants, resurfacing does not lower reintervention rates. This meta-analysis finds no clinical indication to resurface the patellar whilst performing a TKA.

663 A Multi-centre National Study of the Effectiveness of Virtual Fracture Clinic Management of Orthopaedic Trauma during the COVID-19 Pandemic (MAVCOV): A Cross-sectional Study Protocol

Aim

Virtual fracture clinics (VFCs) are advocated by recent British Orthopaedic Association Standards for Trauma and Orthopaedics (BOASTs) to efficiently manage injuries during the COVID-19 pandemic. The primary aim of this national study is to assess the impact of these standards on patient satisfaction and clinical outcome amid the pandemic. The secondary aims are to determine the impact of the pandemic on demographics of injuries presenting to the VFC and to compare outcomes and satisfaction when the BOAST guidelines were first introduced with a subsequent period when local practice would be familiar with these guidelines.

Method

This is a national cross-sectional cohort study comprising centres with VFC services across the United Kingdom. All consecutive adult patients assessed at VFC pre-lockdown (6 May 2019 to 19 May 2019) and at the peak of the first lockdown (4 May 2020 to 17 May 2020), and a randomly selected sample during the second wave (October 2020) will be eligible for the study. Data comprising local VFC practice, patient and injury characteristics, unplanned re-attendances, and complications will be collected. A telephone questionnaire will be used to determine patient satisfaction and patient-reported outcomes for patients who were discharged following VFC assessment without face-to-face consultation.

Results

As of 31 October 2020, 51 hospitals with VFC services have been recruited to participate in this study.

Conclusions

The study results will identify changes in case-mix and numbers of patients managed through VFCs, due to urgent necessity, and whether this is safe and is associated with patient satisfaction to inform future clinical practice.

Advancements in AAV-mediated Gene Therapy for Pompe Disease

Pompe disease (glycogen storage disease type II) is caused by mutations in acid α-glucosidase (GAA) resulting in lysosomal pathology and impairment of the muscular and cardio-pulmonary systems. Enzyme replacement therapy (ERT), the only approved therapy for Pompe disease, improves muscle function by reducing glycogen accumulation but this approach entails several limitations including a short drug half-life and an antibody response that results in reduced efficacy. To address these limitations, new treatments such as gene therapy are under development to increase the intrinsic ability of the affected cells to produce GAA. Key components to gene therapy strategies include the choice of vector, promoter, and the route of administration. The efficacy of gene therapy depends on the ability of the vector to drive gene expression in the target tissue and also on the recipient's immune tolerance to the transgene protein. In this review, we discuss the preclinical and clinical studies that are paving the way for the development of a gene therapy strategy for patients with early and late onset Pompe disease as well as some of the challenges for advancing gene therapy.

Routine fixation of displaced midshaft clavicle fractures is not cost-effective: a cost analysis from a randomized controlled trial

AIMS

The primary aim of this study was to establish the cost-effectiveness of the early fixation of displaced midshaft clavicle fractures.

PATIENTS AND METHODS

A cost analysis was conducted within a randomized controlled trial comparing conservative management (n = 92) versus early plate fixation (n = 86) of displaced midshaft clavicular fractures. The incremental cost-effectiveness ratio (ICER) was used to express the cost per quality-adjusted life-year (QALY). The Six-Dimension Short-Form Health Survey (SF-6D) score was used as the preference-based health index to calculate the cost per QALY at 12 months after the injury.

RESULTS

The mean 12-month SF-6D was 0.9522 (95% confidence interval (CI) 0.9355 to 0.9689) following conservative management and 0.9607 (95% CI 0.9447 to 0.9767) following fixation, giving an advantage for fixation of 0.0085, which was not statistically significant (p = 0.46). The mean cost per patient was £1322.69 for conservative management and £5405.32 for early fixation. This gave an ICER of £480 309.41 per QALY. For a threshold of £20 000 per QALY, the benefit of fixation would need to be present for 24 years to be cost-effective compared with conservative treatment. Linear regression analysis identified nonunion as the only factor to adversely influence the SF-6D at 12 months (p < 0.001).

CONCLUSION

Routine plate fixation of displaced midshaft clavicular fractures is not cost-effective. Nonunion following conservative management has an increased morbidity with comparable expense to early fixation. This may suggest that a targeted approach of fixation in patients who are at higher risk of nonunion would be more cost-effective than the routine fixation of all displaced fractures. Cite this article: Bone Joint J 2019;101-B:995-1001.

Ultrasonic cement removal in cement-in-cement revision total hip arthroplasty: What is the effect on the final cement-in-cement bond?

Objectives

Previous studies have evidenced cement-in-cement techniques as reliable in revision arthroplasty. Commonly, the original cement mantle is reshaped, aiding accurate placement of the new stem. Ultrasonic devices selectively remove cement, preserve host bone, and have lower cortical perforation rates than other techniques. As far as the authors are aware, the impact of ultrasonic devices on final cement-in-cement bonds has not been investigated. This study assessed the impact of cement removal using the Orthosonics System for Cemented Arthroplasty Revision (OSCAR; Orthosonics) on final cement-in-cement bonds.

Methods

A total of 24 specimens were manufactured by pouring cement (Simplex P Bone Cement; Stryker) into stainless steel moulds, with a central rod polished to Stryker Exeter V40 specifications. After cement curing, the rods were removed and eight specimens were allocated to each of three internal surface preparation groups: 1) burr; 2) OSCAR; and 3) no treatment. Internal holes were recemented, and each specimen was cut into 5 mm discs. Shear testing of discs was completed by a technician blinded to the original grouping, recording ultimate shear strengths. Scanning electron microscopy (SEM) was completed, inspecting surfaces of shear-tested specimens.

Results

The mean shear strength for OSCAR-prepared specimens (33.6 MPa) was significantly lower than for the control (46.3 MPa) and burr (45.8 MPa) groups (p < 0.001; one-way analysis of variance (ANOVA) with Tukey’s post hoc analysis). There was no significant difference in shear strengths between control and burr groups (p = 0.57). Scanning electron microscopy of OSCAR specimens revealed evidence of porosity undiscovered in previous studies.

Conclusion

Results show that the cement removal technique impacts on final cement-in-cement bonds. This in vitro study demonstrates significantly weaker bonds when using OSCAR prior to recementation into an old cement mantle compared with cement prepared with a burr or no treatment. This infers that care must be taken in surgical decision-making regarding cement removal techniques used during cement-in-cement revision arthroplasty, suggesting that the risks and benefits of ultrasonic cement removal need consideration.

Cite this article: A. Liddle, M. Webb, N. Clement, S. Green, J. Liddle, M. German, J. Holland. Ultrasonic cement removal in cement-in-cement revision total hip arthroplasty: What is the effect on the final cement-in-cement bond? Bone Joint Res 2019;8:246–252. DOI: 10.1302/2046-3758.86.BJR-2018-0313.R1.

Uncertainty Quantified Computational Analysis of the Energetics of Virus Capsid Assembly

Most of the existing research in assembly pathway prediction/analysis of viral capsids makes the simplifying assumption that the configuration of the intermediate states can be extracted directly from the final configuration of the entire capsid. This assumption does not take into account the conformational changes of the constituent proteins as well as minor changes to the binding interfaces that continue throughout the assembly process until stabilization. This paper presents a statistical-ensemble based approach which samples the configurational space for each monomer with the relative local orientation between monomers, to capture the uncertainties in binding and conformations. Furthermore, instead of using larger capsomers (trimers, pentamers) as building blocks, we allow all possible subassemblies to bind in all possible combinations. We represent the resulting assembly graph in two different ways: First, we use the Wilcoxon signed rank measure to compare the distributions of binding free energy computed on the sampled conformations to predict likely pathways. Second, we represent chemical equilibrium aspects of the transitions as a Bayesian Factor graph where both associations and dissociations are modeled based on concentrations and the binding free energies. We applied these protocols on the feline panleukopenia virus and the Nudaurelia capensis virus. Results from these experiments showed significant departure from those one would obtain if only the static configurations of the proteins were considered. Hence, we establish the importance of an uncertainty-aware protocol for pathway analysis, and provide a statistical framework as an important first step towards assembly pathway prediction with high statistical confidence.

The relationship between the Edinburgh Visual Gait Score, the Gait Profile Score and GMFCS levels I-III

OBJECTIVE

To determine the relationship between the Edinburgh Visual Gait Score (EVGS) and the Gait Profile Score (GPS).

METHOD

Three dimensional gait data and EVGS scores from 151 diplegic children (Gross Motor Function Classification System (GMFCS) levels I-III) were used for analysis.

RESULTS

The EVGS correlated strongly with GPS (r=0.816). There was a significant difference in both gait scores between each level of the GMFCS.

CONCLUSIONS

The strong correlation of GPS with EVGS implies that any advantages of using GPS can also be applied to centres without 3-dimensional gait analysis facilities if the EVGS is used.

Extracellular DNA oxidation stimulates activation of NRF2 and reduces the production of ROS in human mesenchymal stem cells

INTRODUCTION

Human blood normally contains circulating cell-free DNA (cirDNA). Cell-free DNA (cfDNA) present in cell culture medium is termed extracellular DNA (ecDNA). Its concentration, GC content and oxidation level depend on physiological state of the organism. cirDNA could probably be one of the aggressive factors encountered by therapeutic stem cells. The authors hypothesize that oxidized cirDNA could influence their survival rate. They aimed to uncover the effects of oxidized ecDNAs, including ecDNA of cultivated primary tumor cells and cirDNA from blood plasma of cancer patients on mesenchymal stem cells (MSCs).

AREAS COVERED

Increased concentrations of cfDNA stimulate a rapid increase in reactive oxygen species (ROS) synthesis and up-regulate antioxidant response genes (NRF2, KEAP1, SOD1, BRCA1, BCL2) in MSCs. This response is more prominent when cfDNA contains higher proportions of 8-oxo-dG. Within an hour, oxidized DNA induces a decrease in ROS production while NRF2 mRNA levels continue to augment and the NRF2 protein translocates into the nucleus. Additionally, oxidized DNA up-regulates PPRAG2 with no apparent induction of adipogenesis. This kind of response is specific for MSCs.

EXPERT OPINION

Oxidized cfDNA up-regulates NRF2 and PPARG2 and reduces ROS production in MSCs. These effects should be taken into account when considering therapeutic applications of stem cells.

Functional outcomes following ceramic total joint replacement for hallux rigidus

INTRODUCTION

The aim of this study was to evaluate functional outcomes following ceramic arthroplasty used in the treatment of osteoarthritis of the hallux metatarsophalangeal (MTP) joint.

MATERIALS AND METHODS

Thirty-seven consecutive patients who underwent press-fit ceramic joint arthroplasty were identified. Joint movement, gait pressure studies, radiographs, patient's outcome based on the American Orthopaedic Foot and Ankle Society (AOFAS) scale, hallux metatarsal phalangeal-interphalangeal index (HMPI) and visual analogue pain scales were assessed.

RESULTS

Mean follow-up was 33 (12-60) months. Ninety-two percent of patients were satisfied with the surgery. AOFAS and HMPI scores were good to excellent in more than 90%. Six implants had lucent lines of greater than 2mm at 18 months. Three of these joints also had subsidence of both components. There was no correlation between implant loosening and patient outcomes. Mean hallux pressure at toe-off decreased from 7.1 to 3.5 N cm⁻² (p<0.01) equalising with normal contralateral toe pressure. Three patients required revision surgery and one patient had a transient wound infection.

CONCLUSIONS

Good to excellent results have been achieved following ceramic total MTP joint arthroplasty. The clinical relevance of progressive lucencies around the implant is uncertain and longer follow-up may identify subsidence and ultimate failure.

Persistent decrease in proliferative potential of marrow CD34(+)cells exposed to early-acting growth factors after autologous bone marrow transplantation

Post-graft hematopoiesis is characterized by long-term quantitative deficiency in marrow progenitor cells in both autologous and allogenic settings. In order to evaluate the function of post-graft progenitor cells, the proliferative capacity of marrow CD34(+) cells was evaluated in 10 patients 6 months after autologous bone marrow transplantation (ABMT) for non-Hodgkin's lymphoma and compared to that of 10 patients before ABMT and 10 normal controls. Immuno-selected CD34(+) cells were cultured for 7 days in liquid serum-free medium with a combination of early-acting GF consisting of stem cell factor, IL-3 and IL-1beta. Clonogenic efficiency of unselected cells for CFU-GM and BFU-E was decreased in post-graft patients compared to pre-graft and control patients. However, clonogenic efficiency of selected CD34(+) cells for CFU-GM was not different in post-graft, pre-graft and control patients but BFU-E values of post-graft patients remained lower than those of control patients. Decreased percentages of CD34(+) CD38(-) cells were observed in both post-graft and pre-graft patients while those of CD34(+) c-kit(+) cells were similar in all three patient groups. After 7-day liquid culture, expansion yields of total progenitor cells were significantly lower in post-graft patients (147 +/- 28%) than in pre-graft (255 +/- 27%) and control patients (246 +/- 23%). Post-graft deficiency in progenitor cell expansion was particularly marked for BFU-E (61 +/- 24%) compared to pre-graft patients (220 +/- 82%) and to controls (349 +/- 82%). These results indicate impaired proliferative potential of marrow CD34(+) cells several months after ABMT involving erythroid progenitor cells and/or commitment towards erythroid lineage from a more immature stage (pre-CFU).

[Adrenal medullary hyperplasia: a rare etiology of arterial hypertension--report of a case]

Adrenal medullary hyperplasia is often misdiagnosed. The clinical features may resemble those of pheochromocytoma, with paroxysmal hypertension and elevated urinary catecholamine and metanephrine levels. Pathologic study shows diffuse or nodular adrenal medullary hyperplasia, determined by morphometric analysis: increased adrenal gland weight, increased relative medullary volume, increased relative medullary weight, decreased cortico-medullary ratio. Adrenal medullary hyperplasia may be primary or sporadic, but is often associated with multiple endocrine neoplasia (MEN) type II.

[Congenital hepatic fibrosis. Five cases with late occurrence in adults]

Congenital hepatic fibrosis (CHF), is an autosomal recessive disease, presenting principally in childhood with portal hypertension and/or cholangitis, and often associated with renal malformations. The forms presenting later in adults are rare, and illustrated herein by 4 cases with dominant cholangitis, and one latent form. Biological tests and radiological imaging are often normal. The histopathologic diagnosis, sometimes difficult on liver needle biopsy is based on fibrous enlargement of portal areas, with numerous and tortuous bile ducts, lined by regular, cuboidal epithelium. Interportal fibrosis can mimic cirrhosis. In CHF, cholangitis are favoured by intrahepatic biliary dilatation, sometimes related to Caroli's disease, associated in 25% of cases. Suppurative complications, sometimes fatal explain the severity of cholangitis forms of CHF, contraindicating inopportune cholangiography and biliary surgery.

[Adenomatoid tumors of the uterus. Study of 5 cases with immunohistochemical and ultrastructural confirmation of the mesothelial origin]

Five cases of adenomatoid tumors of the uterus (ATU) are reported. These benign lesions are discovered in 1% of the hysterectomy specimens, performed on 20- to 85-years-old women. Their frequency is certainly underestimated, since ATU have the same macroscopic appearance as leiomyomas. Histologically, ATU are formed by gland-like and pseudovascular lumens, lined by regular, cuboidal or flattened cells, and surrounded by hyperplastic smooth muscle bundles. Immunohistochemical coexpression of cytokeratin and vimentin confirms with a mesothelial histogenesis. The ultrastructural study, showing luminal microvilli and desmosomes supports the hamartomatous development of ATU, corresponding to mesothelial inclusions from the peritoneum into the myometrium. Some giant or diffuse ATU, which are clinically disturbing, are differentiated from carcinomatous or vascular proliferations by frozen section examination. The treatment is made by surgical excision.