Outcomes following reverse total shoulder arthroplasty vs operative fixation for proximal humerus fractures: a systematic review and meta-analysis

INTRODUCTION

Proximal humerus fractures are common in the older population. A consensus on the optimal management of complex fractures requiring surgery has yet to be reached. A systematic review and meta-analysis was performed to compare clinical outcomes between reverse total shoulder arthroplasty (RTSA) and open reduction and internal fixation (ORIF).

METHODS

A systematic search of the literature was undertaken using the Medline®, PubMed, Embase™ and Cochrane Central Register of Controlled Trials databases. Prospective and retrospective studies comparing clinical and patient reported results as primary outcome measures were included in this review, with secondary outcome measures including complications and revision surgery. A meta-analysis was conducted.

RESULTS

A total of 326 patients from 5 studies were eligible for inclusion in this review. Superior Constant-Murley scores (mean difference [MD]: 13.4, 95% confidence interval [CI]: 6.2-20.6; p<0.001), Oxford shoulder scores (MD: 4.3, 95% CI: 1.2-7.4; p=0.007), simple shoulder test scores (MD: 0.95, 95% CI: 0.01-1.89; p=0.05) and DASH (Disabilities of the Arm, Shoulder and Hand) scores (MD: 5.1 [1 study], 95% CI: 2.1-8.1; p=0.034) were noted in patients receiving RTSA. Range of motion and revision surgery rates were also superior in this group.

CONCLUSIONS

This study suggests that RTSA affords more favourable outcomes and lower revision rates than ORIF following proximal humerus fractures. Definitive conclusions are precluded, however, owing to small sample sizes and risk of bias in retrospective studies.

Cannulated screw versus Kirschner-wire fixation for Milch II lateral condyle fractures in a paediatric sawbone model: a biomechanical comparison

PURPOSE

Lateral condyle fractures of the humerus are common in the paediatric population, accounting for up to 20% of elbow fractures. Traditional management involves internal fixation with Kirschner (K)-wires, however, this has been associated with complications and insufficiently rigid fixation. Recently, cannulated screws have been proposed as a more stable method of fixation. While cannulated screws have been thought to allow earlier range of movement and shorten time to union, data regarding the biomechanical performance and optimal screw placement is scarce. We hypothesize that cannulated screw fixation is superior to K-wire fixation and screw placement can enhance the stability of the construct.

METHODS

Paediatric humerus sawbones with Milch II fractures were fixed with one of three methods. Fractures were reduced with either a single cannulated screw either through the centre of the capitellum (oblique), or placed up the lateral column across the growth plate (lateral), or fixed with two K-wires. Fixed sawbone fractures were then mechanically tested in two directions simulating in vivo forces.

RESULTS

The lateral screw construct had a higher maximum force to failure, higher stiffness and absorbed higher energy as compared with the K-wire fixation and oblique screw under an anterior force. When loaded from the posterior direction, only the lateral column screw was better than K-wire fixation.

CONCLUSIONS

Screw fixation is a biomechanically effective alternative to K-wire fixation, especially when placed up the lateral column of the distal humerus. Further clinical studies are required before transcapitellar screw fixation can be adopted.

Profile of epidermal growth factor receptor (EGFr) expression in human malignancies: effects of exposure to EGF and its biological influence on established human tumour cell lines

The aim of this study was to compare the profile of EGFr expression in transitional cell carcinoma of the bladder (TCC) and in oral squamous cell carcinoma (OSCC). In addition, to study the influence of EGF stimulation on the expression of major histocompatibility complex class I antigens, placental alkaline phosphatase (PLAP) as well as changes in tumour cell sensitivity to cisplatin using immunocytochemical staining, a colorimetric assay and SDS-gel electrophoresis. The results showed that: a) strong EGFr expression could be seen in 22/88 (27%) cases of TCCs. In oral tumours the values for non-invasive ameloblastoma and invasive OSCC were 4/25 (16%) and 30/41 (73%) respectively. b) EGFr expression in tumour cell lines paralleled that of tumour biopsies. The number of lines expressing high and low EGFr expression amongst TCCs were 4 and 4 and in OSCCs were 3 and 1 respectively. c) Exposure of tumour cell lines to EGF led to: i) an increase in EGFr expression (stimulatory indices SI, ranged from 1.06 to 2.58) for TCCs but a decrease in the case of OSCCs (SI ranged from 0.01 to 0.85). The corresponding SI values for class I antigens were 0.95-1.16 and 0.10-0.84. ii) A significant reduction in expression of PLAP by OSCC cell lines. iii) An increased susceptibility of OSCC cell lines to cisplatin by as much as 14% (p<0.001). These data demonstrated the overexpression of EGFr in a significant proportion of TCCs. As for oral tumours it depended on whether they were of an invasive or non-invasive type. In the invasive cases the majority overexpressed EGFr. The exposure of OSCC but not TCC tumour cells to EGF resulted in down regulation of EGFr and class I antigens. The expression of PLAP was also significantly reduced. Exposure of OSCC cells to EGF resulted in their increased susceptibility to cisplatin. The data supports the notion that the mitogenic activation of some tumour cells by EGF resulted in a reduction of their immune visibility, differentiation status and an increase in chemosensitivity.

Concordance between tumour cell activation by epidermal growth factor and alteration of cell sensitivity to cisplatin and lymphokine-activated killer cell activity

In this study the impact of epidermal growth factor (EGF) on chemosensitivity and susceptibility to lymphokine-activated killer (LAK) cytolysis on six cell lines (one super expressing EGFr i.e. HN5, three high expressing i.e. Hep2, KB and MCF-7 and two low expressing i.e. Fen and HN15) was investigated using the tetrazolium salt reduction assay (MTT) as measured by optical density (OD). Hep2, KB, MCF-7 and Fen lines showed a dose-related inhibition to cisplatin (from 19% to 80%). Treatment of EGFr positive cell lines, Hep2, KB and MCF-7 but not EGFr negative Fen by EGF prior to exposure to cisplatin inhibited the cells by between 10-15% (p<0.05). Exposure of HN5 line to EGF (0.1 ng/ml) prior to LAK assay, led to a decrease in tumour killing (13%, p<0.05). However, at 0.01 ng/ml the pre-treatment enhanced tumour sensitivity. These data indicated that pre-exposure of tumour cells to EGF altered their response to cisplatin and LAK killing and this depended on the degree of EGFr expression. These data may prove helpful for pre-selection of patients for an appropriate therapy.

Local anergy rather than systemic anti-tumour immunity to explain tumour growth in an animal model of oral squamous cell carcinoma

A chemically induced syngeneic hamster tumour model of human oral squamous cell carcinoma (OSCC) was used to investigate the possible influence of locally transplanted growing rumours on the immune system of the recipient. Cell activation and cell cytotoxicity assays were performed in vitro using the colorimetric MTT assay to measure any possible changes. The fast growing nature of the tumour model if grafted locally as a fragment was confirmed but not if injected as a single cell suspension (SCS). Stimulation (Concanavalin A) of spleen cells from normal and from tumour bearing animals showed that there was a minor though statistically significant decrease in the mitogenic response of the latter. Thus, the respective stimulatory indices (SI) were 4.06+/-1.61 and 2.06+/-0.87 (0.02<p>0.01). No significant difference was observed when spleen cells were stimulated with interleukin-2 (IL-2), although there was a similar trend. Pre-immunisation of animals with irradiated autologous SCS three weeks prior to grafting, resulted in a significant decrease in the tumour growth rate of subsequently grafted tumour. Thus, the mean If: SD (weight of takes in mg) for the successful takes of untreated (n=10) and treated (n=9) groups were 52.0+/-52.2 and 25.7+/-19.4 (0.02<p>0.05) respectively. The number of cases with no tumour takes were 2 of 10 (20%) and 6 of 9 (66%) respectively. In a separate experiment groups of 5 animals were immunized with an increasing number of cells as irradiated SCS, the results of which demonstrated an inverse correlation between the rate of tumour growth and the number of injected tumour cells. The addition of irradiated SCS to IL-2 activated normal spleen cells (LAK cells) in vitro led to a dose-related decrease in the efficiency of cytotoxicity of latter when tested against an xenogeneic super-sensitive surrogate tumour target cell line (Fen cells). Thus, the percent killing by IL-2-activated normal spleen cells was 56.4%. The corresponding mean values for IL-2 activated normal spleen cells in the presence of tumour SCS at 25/1 and 50/1 ratios were 35.9% (p<0.05) and 11.9% (p<0.001) respectively. Ln an attempt to establish the presence of T suppressor cells, spleen cells from tumour bearing animals were injected concomitantly with SCS into 5 recipients. After four weeks no tumour growth had occurred. In conclusion we demonstrated that the presence of injected or grafted tumour had only a minor effect on systemic immune function but induced a strong local anergic effect. This local anergic effect was demonstrable as blocking of LAK activity and thus perhaps allowed suppression of the functional activities of incoming immunocompetent cells.

Characteristics of human tumour cell lines after induction of multidrug resistance

A colorimetric technique was used to investigate some aspects of multidrug resistant (MDR)-induced cell lines. Continuous contact of the inducing agent with cells was necessary for MDR induction and this was followed by a series of phases i.e., a selection phase (ESP) lasted up to 6 days, a conditioning phase (CP) lasted up to 14 days and an expansion phase (EP) lasted up to 7 days. Gene transfection to correct missing MHC class I antigens on the Fen cell line did not affect cell behaviour. Of particular interest was the finding that the withdrawal of the MDR inducing agent did not reverse MDR phenotype immediately.

Expression of glutathione-s-transferase isotypes in relation to Doxorubicin sensitivity and prognosis in patients with renal-carcinoma

Specimens were obtained from the tumour and adjacent normal kidney in 29 patients with renal carcinoma. Expression of the alpha, pi and mu isoforms of gluthatione-S-transferase (GST) was estimated in formalin fixed paraffin embedded sections of the normal and neoplastic kidney following exposure to the appropriate polyclonal antibodies. binding of which was recognised by the indirect peroxidase technique. Expression of alpha, pi and mu GST in each tumour specimen was compared with the in vitro sensitivity of tumour cells to doxorubicin determined by drug inhibition of [Se-75] selenomethionine uptake by the appropriate tumour cells in culture. Expression of pi GST was associated with tumour cell resistance to doxorubicin. The level of alpha, pi and mu GST was not related to patient survival.

P-glycoprotein expression, tumor differentiation, chemosensitivity of tumor-cells in-vitro and clinical outcome in patients with renal-cell carcinoma

There was no association between expression of P-170 glycoprotein on cells derived from 14 renal carcinomas and the in vitro sensitivity of the cells to doxorubicin or its potentiation by verapamil. Furthermore expression of P-170 on the cells of individual tumours was unrelated to nuclear differentiation or patient prognosis. These observations may in part resolve the dilemma posed by the reported association in some tumour types between expression of P-170 and the metastatic phenotype together with the previously observed relation in renal carcinoma between P-170 expression, good tumour differentiation and therefore a favourable prognosis.

Multidrug-resistance due to p-glycoprotein

Multi-drug resistance (MDR) is due to the presence in neoplastic cells of the transmembrane glycoprotein P-170. The P-170 increases drug efflux by combining with the drug and adenosine triphosphate. This energy dependent drug efflux may be reversed by agents, e.g. verapamil, which compete with drugs for receptors on the plasma membrane. High expression of P-170 is associated with reduced sensitivity to MDR-associated cytotoxic drugs, e.g. doxorubicin in vitro by renal and breast carcinoma cells. Verapamil has been most effective in increasing the effect of chemotherapy in patients with multiple myeloma. In contrast, negative results have been reported for 'solid' tumours such as carcinoma of the colon and kidney.