Considering the scarcity of good quality primary source data there is a surprisingly vast amount of review papers and meta-analysis on flail chest. There are four important review-like papers on the topic [16, 25–27]. The most comprehensive of all is of the practice management guideline for flail chest of the Eastern Association for Surgery of the Trauma published in 2012 [16]. The literature research process yielded 37 studies published between 2005 and 2011. It replaces the previous guideline, which provided evidences for the practice 7 years ago, based on 92 studies published between 1966 and 2005 [28]. The new answer to the old question, is there a role for surgical fixation of flail chest injuries, has remained the same: yes, in certain cases. The conditional recommendations according to the GRADE approach [28] are that surgical fixation may be considered in cases of severe FC failing to wean from the ventilator. Prophylactic fracture fixation was discouraged as no benefit has been identified so far. “On the way out” osteosynthesis was included in the Recommendations [16].

A systemic review and meta-analysis of Leinicke et al. published in 2013 on 9 studies (2 RCT, 4 CS, 3 CCS) have evaluated the outcome of 538 cases [25]. There was a benefit of surgery vs pneumatic stabilization in duration of mechanical ventilation (4.52 days) and intensive care bed occupancy (3.4 days) evident in the pooled database. Relative risk (RR) for tracheostomy was 0.25 in the operative group. Statistical differences support a surgical approach for decreased mortality (RR:0.44) and pneumonia (RR:0.45), but vast heterogeneity and patient allocation in the sources cast a shadow on the validity of the observations. The paper had strong and adequate statistical power but the pre-selection bias dominating the patient pool (n: 459) seriously limited the clinical applicability of the message.

Another meta-analysis by Slobogean et al. in 2013 harvested nearly the same database [26]. The authors omitted the article of de Moya et al. from 2011 [29] focusing on pain in FC and of Althausen et al.[30] on locked plate fixation, two case-control studies considered in Leinecke’s analysis. In comparison with Leinecke’s work, Slobeogean et al. created a pool of 753 cases of which only 100 participated in publication in the new millennium having added the series of Borelly (n = 176) [31], Kim (n = 63) [32] Ohreser (n = 14) [33] and Teng (n = 60) [34]. One third of the cases was treated more than 30 years ago. The paper reports an advantage for surgical fixation in ventilator days (8 day difference) and pneumonia (odds ratio: 0.2). A decrease in intensive care bed occupancy (5 days) mortality (odds ratio: 0.31) septicemia (odds ratio: 0.36) and tracheostomy (odds ratio: 0.06) were also calculated. The extremely long time span and the heterogeneity of the pooled data counterweight the advantages of the analysis.

Bhatnagar et al. promising in their 2012 paper a focused look at the FC problem utilizing sophisticated statistical methods [27]. The message of their Markov model driven paper is clearly in favor of rib fracture fixation, however their utilized database is actually not visible to the average reader. Coding bias influencing their calculation based on US National Trauma Data Bank and shortcomings of primary reports detailed above make the paper unsuitable for bedside problem solving. Open reduction and internal fixation of ribs for flail chest in a clinically blind budget oriented analysis represents the most cost effective strategy by $8,400 USD. The main benefit of this paper is the letter to the editor of Paydar et al. [35] who are calling for a proper chest wall injury classification to be able to identify the very subset of patients who really might benefit from surgical approach.

There are two further papers to be mentioned here as they contribute to the present debate in a significant amount and manner. Nirula and Mayberry summarize the ruling opinions on potential indications for selective operative rib fracture in their paper with 116 references [36]. Open chest defects and pulmonary hernia are supported by case series. Decision for surgery in FC in cases of non-healing ribs and “thoracotomy on the way out” is supported by case series but the expert opinion is divided. Reduction of acute pain and disability are no go areas: unproven and controversial. Lafferty et al. in their 2011 current concepts review on chest wall injuries [37] concludes that there are occasional scenarios where osteosynthesis of broken ribs should be considered. The reference list is 103 items long. The operative indications in their interpretation are always relative. The individualized decision should be optimized to the pattern of rib fracture, the patient’s overall status (age, comorbidities etc.).

There are five non-randomized observational studies [29, 30, 34, 38, 39] in the last decade suggesting that hazily defined subset of patients might benefit from surgery in terms of pneumonia and other ventilation related complications. These advanced audit like retrospective studies are bravely arguing for osteosynthesis without contextualizing their own results with respect to non-surgical alternatives i.e. pneumatic stabilization by different ventilatory strategies (invasive and non-invasive methods). On the other hand Athanassiadi and colleagues [10] in their well balanced and sober analysis of 250 flail chest injuries published in 2010 identified the high Injury Severity Score (ISS) value as the most significant prognostic factor. One hundred and five of their patients (42 %) had isolated flail chest, none of them was operated on. In addition, the resort to mechanical ventilation was not found to be necessary to achieve positive outcome [10]. The authors performed six operative stabilization “on the way out” of the 11/250 patients, who required thoracotomy for other reason. It worth to mention, that this paper of vast case number is missing from all the meta-analyses discussed above. Similar conservative attitude is reported in another observational study from Turkey in 2009, where 4205 chest trauma cases were analyzed [40]. None of their 72 flail chest patients (1.7 %) seen over 10 years of experience was operated on. Similarly, only 1.3 % of 154 flail chest patients required surgical stabilization in the series of Cannon et al. between 2001 and 2010 [22]. Their highly conservative approach resulted in a 9.1 % FC-related mortality.

Further papers highlight the importance of lung contusion/acute lung injury in outcome. As early as in 1997 the milestone study of Voggenreter et al. [41] emphasized the importance of the lung contusion in the outcome of flail chest. It is worth mentioning that two recent overviews of the question also emphasize [4, 42] the definitive role of lung injury in the optimal treatment of chest wall injury, flail chest included. In spite of this warning neither the three RCTs nor the relevant cohort studies implemented this important cofactor into their analyses. This is one of the main reasons why their results and conclusions are received with some sort of doubt. Lung injury combined with rib fracture predicts respiratory failure where CT diagnosis has a definitive role [43]. In a series of 408 multiple rib fractures lung contusion was about ten times more frequent than flail chest (22 % vs 2.3 %) which latter required artificial ventilation but no surgery in eight cases out of the ten [44]. Pulmonary contusion and flail chest were recently identified as strong predictors of development of ARDS in trauma patients [45]. It is proven, that as lung contusion and resulting injury exceeds 20 % of total pulmonary parenchyma, the probability of the onset of ARDS sharply increases [46]. Chest CT in combination with the dynamic changes of blood gases are proper tailoring tools for measuring the 20–25 % threshold which excludes surgical fixation [47].