Introduction

Clavicle fractures account approximately 2.6–4% of all fractures in the adult population [1, 2]. Of them, distal clavicle fractures (DCF) account up to 28% [1, 2]. The majority of DCF occur after a direct fall over the shoulder or, in smaller part, after a fall on outstretched hand [3,4,5,6]. Management of DCF can be challenging. Most classifications for DCF are mainly based on the configurations of bone fragments (stable or unstable) and the location in relation to the coracoclavicular ligaments [3, 7,8,9,10]. Stable lesions can be treated conservatively; however, failing to identify unstable lesions could result in pseudoarthrosis/nonunion and poor shoulder function [11,12,13,14]. Several surgical techniques have been described to manage unstable DCF, but to the best of our knowledge, no consensus has been reached [11, 15,16,17,18]. Surgical management can be categorized as rigid (locking and hook plates) and elastic (Kirshner-wire fixation, tension band wiring, suture anchors, button suture systems) fracture fixation, or a combination of both. The surgical procedure can be open, arthroscopically assisted, or fully arthroscopic [17, 19].

The incidence of associated lesion after DCF is highly variable [6, 20,21,22,23,24]. Preoperative physical examination to investigate concomitant injuries to DCF can be difficult because of pain and inflammation. Moreover, MRI or diagnostic arthroscopy of the glenohumeral joint to investigate associated is not routinely performed [24]. This systematic review investigated the incidence of concomitant intra-articular glenohumeral injuries in patients undergoing surgical management of DCF using concomitant intra-operative shoulder arthroscopy.

Methods

Search strategy

This systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [25]. Two independent reviewers (T.M.F., J.M.H.) accessed PubMed, EMBASE, and Virtual Health Library databases in October 2021. The following terms "distal clavicle fracture" and "arthroscopy” were used alone and in combination with the Boolean operators AND and OR. Inclusion and exclusion criteria were established before the search and were used to identify potentially eligible studies by title and abstract screening. Disagreements between reviewers were resolved by a third investigator (E.P.). The bibliography of the included studies was screened by hand to identify additional studies.

Eligibility criteria

All the clinical studies evaluating the surgical management of DCF and using concomitant intra-operatory shoulder arthroscopy were included. Only studies in English were included. Only studies published in peer reviewed journal with a minimum of 5 patients were considered. Reviews, comments, opinions, and editorials were not eligible. Studies which reported data on insolated DCF without arthroscopy were not eligible. Studies which did not specify the concomitant injury type were also not eligible. Studies which reported shoulder injuries associated with DCF in other forms rather than a direct arthroscopic visualization were not included.

Data extraction

Two independent investigators (T.M.F., J.M.H) performed data extraction. Studies generalities (author, year, type of study, and level of evidence) were extracted. Data from the following endpoints were retrieved: number of patients, classification, incidence of intra-articular glenohumeral injuries, injury type, length of the follow-up, clinical outcomes.

Methodological quality assessment

The quantitative content assessment was performed using the Strengthening the Reporting of Observational Studies in Epidemiology: the STROBE statement checklist (SSc) [26].

Assessment of publication bias

Evaluation of the publication bias of the included studies was performed using the risk of bias assessment tool for systematic reviews (ROBIS) [27]. This tool was developed to assess the risk of bias in systematic reviews and meta-analysis. The ROBIS is composed by three parts: (1) assessment of relevance (optional), (2) identification of concerns with the review process (study eligibility criteria; identification and selection of studies; data collection and study appraisal; and synthesis and findings), and (3) evaluation of the risk of bias in the review process, results and conclusions.

Statistical analysis

The statistical analysis was performed using IBM SPSS Version 19 and Microsoft Excel 2016 (Microsoft, USA). Data were presented in tables using absolute values, standard deviations, and percentages from individual studies. Values of P < 0.05 were considered statistically significant.

Results

Search results

The initial literature search yielded 74 potentially relevant records after the removal of duplicates (N = 27). Titles and abstracts were screened, and 18 articles for full-text evaluation were retrieved. Seven studies met the predetermined eligibility criteria [21,22,23,24, 28,29,30], and three additional studies were included after citation screening [31,32,33] (Fig. 1). There were five retrospective [21, 24, 28, 31, 32] and five prospective cohort studies [22, 23, 29, 30, 33].

Fig. 1
figure 1

Flow chart of the literature search

Full size image

Methodological quality assessment

The SSc was used to assess the quality of individual studies in the present investigation (Table 1). The average SSc value was 26.30 of 32 (range 22–31), indicating a good quality of the methodological assessment.

Table 1 STROBE Statement checklist score of included cohort studies
Full size table

Assessment of publication bias

The risk of bias in the review was low (Fig. 2). A low heterogeneity among the included studies was observed in the arthroscopic assessment of intra-articular glenohumeral concomitant injuries, in the standardization of the surgical procedure, and postoperative management. Most studies clearly defined the type of lesion and referred to standardized classifications.

Fig. 2
figure 2

Assessment of publication bias

Full size image

Synthesis of Results

Eight of the included studies were conducted on patient cohorts with Neer type II injuries [21, 22, 24, 28,29,30, 32, 33]. Data pooling revealed a mean of 17.70% of concomitant glenohumeral injuries, whereas 84.21% of them required additional surgical management (Table 2).

Table 2 Incidence of intra-articular injuries in distal clavicular fractures and injury type among the included studies
Full size table

Helfen et al. [24] assessed the clinical outcomes in patients with and without concomitant injuries, finding no differences in Constant and Oxford shoulder score at last follow-up. Xiong et al. [29] reported a prolonged rehabilitation in patients with concomitant injuries. Concomitant glenohumeral injuries were summarized (Table 3).

Table 3 Distribution of concomitant injuries according to their type in distal clavicular fractures among the included studies
Full size table

Discussion

The present systematic review highlighted that 17.70% of patients with acute DCF evidenced concomitant glenohumeral injuries. Rotator cuff injuries, labral tears, and biceps pulley lesions were the most common concomitant injuries, requiring additional surgical treatment in 84.21% of cases. This incidence is similar to those reported following after acromioclavicular dislocations [20]. This similarity may result from to the similar mechanism of injury [6]. Preoperative MRI or diagnostic arthroscopy to evaluate glenohumeral associated injuries to DCF should be recommended.

The management of concomitant injuries to the DFC have demonstrated clinical improvement and may avoid persistent symptoms and early onset of degenerative changes [34,35,36]. However, the current evidence is not strong enough to ascertain whether concomitant glenohumeral injuries in DCF may affect the final outcome of management of these injuries.

DCF have been traditionally managed through open approaches with very satisfying outcomes, and further imaging or arthroscopic assessments are related to increased surgical time and costs [28, 37]. However, the acute pain following an acute DCF, or the administration of pain medications, may jeopardize the presence of concomitant shoulder injuries. Therefore, the presence of concomitant injuries should be evaluated using preoperative MRI or diagnostic arthroscopy in patients with DCF. Whether to combine the management of DCF with a simultaneous or delayed additional glenohumeral intervention should be evaluated for each patient, and surgery should be individualized.

This study has several limitations. The small number of included studies and relatively small sample size is the most important limitation of the present systematic review. The retrospective nature of 50% (5 of 10) of included studies increases the risk of selection bias. None of the included studies performed randomization or blinding, thus increasing the risk of detection bias. Most of the included studies were conducted on patients with DCF type II according to the Neer [7]. Thus, results from this systematic review may be not fully generalized. Further high-quality investigations should be performed to overcome current limitations and to evaluate the efficacy and safety of simultaneous glenohumeral interventions.

Conclusion

17.70% of patients with a DCF evidenced concomitant glenohumeral injuries. Rotator cuff injuries, labral tears, and biceps pulley lesions were the most common concomitant injuries, requiring additional surgical treatment in 84.21% of cases. Preoperative MRI or diagnostic arthroscopy to evaluate glenohumeral associated injuries to DCF should be recommended.