Surgical Management of Acute Acromioclavicular Type 3 Separation: A Systematic Review and Meta-analysis of RCTs

Acromioclavicular (AC) joint dislocations are common, particularly among active individuals, accounting for approximately 9% of all shoulder injuries [1,2]. Despite their high incidence, managing high-grade AC separations remains a subject of debate. The lack of standardized treatment protocols and the absence of robust, evidence-based guidelines contribute to the uncertainty about the best treatment approach, especially regarding the potential for chronic shoulder pain [3,4]. Additionally, clinical recommendations concerning the timing of surgery, surgical indications, and fixation methods continue to differ [5].

Research indicates a significantly higher incidence rate among young athletes engaged in contact sports, as well as in manual laborers. Moreover, ACJ injuries are about five times more common in men than in women [6]. Similarly,

According to Sim et al, 53% of injuries were linked to sports activities such as cycling, football, martial arts, ice hockey alpine skiing, and snowboarding with males accounting for 82% of these injuries [3].

In 1984, Rockwood first described his six-part classification system for AC joint separations [7]. His classification of Acromioclavicular dislocation is based on the direction as well as the degree of clavicular displacement [8]. In fact, grades I and II are considered mild and are commonly recommended for conservative management [9,10].

For Type III injuries, conservative treatment is generally preferred for patients with lower physical activity levels, underlying health conditions, or complications. However, surgical intervention is typically recommended for professional athletes or highly active individuals. As a rule, surgical management is the first choice for Type III injuries and those of higher grades [11,12]. In cases where there is minimal to no displacement (Rockwood Grades I and II), conservative management is typically sufficient, with or without splint support. Surgical options, however, are often necessary when displacement occurs, particularly in young athletic patients. These options include open reduction with methods such as temporary pinning, coracoclavicular (CC) screw fixation, hook plate, or ligament reconstruction [13,14,15]. Recent evidence suggests that for most acute Type III injuries, including those in athletes involved in contact sports, initial conservative treatment is recommended. Surgical intervention should be considered if there is significant horizontal instability, in high-performance athletes (such as throwing athletes), or when initial conservative treatments fail to address persistent pain or instability [16].

The management of Type III AC joint injuries has been debated for years, and few studies have conclusively shown that surgical treatment provides superior outcomes [17,18,19]. Although several treatment methods are available for managing high-grade AC separations, none have emerged as the definitive standard of care. These methods include CC screw fixation, suture fixation, Kirschner wire or hook plate (HP) fixation, as well as newer cortical fixation techniques like suture button constructs (SBCs) [20,21,22,23,24]. Despite the availability of these techniques, complication rates, such as hardware failure, migration, under-correction, loss of reduction (LOR), and fractures of the coracoid and clavicle, remain high [21,22,24].

The TightRope technique (Arthrex, USA) is a minimally invasive method that stabilizes the AC joint by enhancing the coracoclavicular (CC) complex with a high-strength suture. An alternative open procedure is the clavicular hook plate (AO), where the plate is fixed with screws on the superior surface of the clavicle, and the hook is transarticularly secured at the lower surface of the acromion [25]. Recent studies suggest that compared to the clavicular hook plate, the arthroscopic TightRope loop titanium button offers a minimally invasive, safe, and effective solution for treating AC joint dislocations, yielding promising clinical outcomes [12]. The TightRope technique is advantageous due to its minimally invasive nature, lower complication rates, and superior clinical results [26].

On one hand, those who support non-operative procedures argue that patients frequently achieve outstanding clinical outcomes and regain painless shoulder function, yet some individuals may experience the risk of chronic instability and pain [27,28].

Currently, the management of Grade III dislocations is determined by the surgeon's preference, the patient's age, and activity level. Studies in the scientific literature have shown comparable outcomes between surgical and non-surgical treatments. While non-operative methods lower the risks of postoperative complications, some individuals may continue to experience lingering pain and cosmetic irregularities. Surgical procedures, on the other hand, are associated with higher complication rates but can facilitate the anatomical restoration of the scapular girdle [29].

The management of acromioclavicular dislocation grade III remains a subject of ongoing debate within the orthopedic community, reflecting the complexity and variability of treatment approaches for this specific injury grade. While several studies have examined the effectiveness of surgical versus non-surgical management, findings remain inconsistent due to differences in patient populations, follow-up durations, and surgical techniques. Additionally, the role of Tightrope fixation compared to other surgical methods is not well-established. This systematic review seeks to fill the research gap by evaluating functional and cosmetic outcomes of different treatment approaches and comparing the clinical outcomes of patients undergoing operative and non-operative management following grade III acromioclavicular dislocation. This review aims to provide valuable insights into the efficacy, safety, and patient outcomes associated with these treatment modalities by analyzing the existing evidence.

Search Design

This study adhered to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to ensure transparency, reproducibility, and methodological rigor.

Search Strategy and Study design

A comprehensive literature search was conducted in PubMed, Web of Science, and Cochrane databases using the following search terms: (Acromioclavicular dislocation OR AC joint dislocation OR AC separation) AND (Type 3 OR Grade 3) AND (Acute OR recent) AND (Surgical management OR surgical treatment OR surgery OR operative treatment). A total of 480 articles were identified (275 from PubMed, 168 from Web of Science, and 37 from Cochrane). After removing duplicates, 369 articles were screened, of which 6 studies were included. Eligible studies were randomized controlled trials (RCTs) published in English without time frame limitations, reporting outcomes relevant to the research objectives, such as functional outcomes, complication rates, recurrence, and patient satisfaction. Studies were removed based on several predefined criteria, including those employing interventions misaligned with the research focus, displaying methodological inconsistencies, or appearing in languages other than English. Additionally, studies were excluded if they involved patients who lost follow-up before assessment, lacked pertinent data, or employed inappropriate studies such as meta-analyses, systematic reviews, economic analyses, animal models, in-vitro studies, cadaver studies, narrative reviews, editorials, case series, or case reports.

Moreover, exclusion criteria extended to studies involving participants with chronic conditions or comorbidities that could influence treatment results, those including participants younger than 18 years to maintain consistency within the adult population, and studies with inadequate follow-up durations potentially compromising the evaluation of long-term results. The inclusion criteria aimed to identify studies addressing patients with Grade III AC joint dislocations and reporting essential findings, such as functional performance, complication rates, and patient satisfaction. These criteria aimed to reduce potential confounding factors and ensure the inclusion of studies providing the most relevant and reliable data for comparing treatment strategies.

The randomized controlled trials (RCTs) included in this review were carefully chosen to minimize potential biases. However, certain biases may persist due to the selection process. These biases include selection bias resulting from variations in inclusion and exclusion criteria across the studies, potentially affecting the generalizability of the findings. Publication bias may also be present, as studies with positive results are more likely to be published, which could distort the overall conclusions. The limited number of included studies and the lack of diversity within the sample may also contribute to performance and detection biases.

Sampling

The sample size of 345 patients across six RCTs was deemed sufficient to provide adequate statistical power for comparing surgical and non-surgical interventions. Incorporating multiple studies enhanced the generalizability of the findings by reducing the influence of individual study biases. Patient demographics, including age, gender, and activity level, were examined to evaluate their potential impact on treatment results. These variables were systematically collected and analyzed to assess their effect on functional outcomes, complication rates, and recurrence. The inclusion of diverse patient populations aimed to strengthen the reliability and applicability of the findings to the general adult population affected by Grade III AC joint dislocations.

Data extraction

Four reviewers (M.H., R.M., J.A., and W.M.) independently performed a thorough screening of all identified studies to evaluate their eligibility for inclusion, with any discrepancies adjudicated through discussion with a fifth reviewer (A.G.). Data extraction was systematically conducted to capture critical study characteristics, including authorship, year of publication, geographic location, study design, sample size, and length of follow-up. Detailed patient demographic and clinical variables, such as age, sex, body mass index, underlying conditions (e.g., preexisting injuries or comorbidities), and symptom duration, were meticulously recorded. Data related to surgical interventions were extracted, encompassing the type of procedure, surgical techniques, fixation methods, and postoperative rehabilitation protocols. Outcomes of interest included measures of postoperative joint stability, functional outcomes (e.g., range of motion, return to activity), complication rates, patient-reported outcomes, and follow-up duration.

Handling of Missing Data & Reporting Bias

At multiple stages, data reliability and completeness were accounted for, including addressing missing data. Particular attention was given to studies not reporting on several relevant descriptors, including functional outcomes, complication rate, or recurrence rate. Qualitatively, those studies with missing important data were discussed, but they did not feature in individual analyses. Furthermore, sensitivity analyses were conducted to determine the influence that restricting analysis to studies with more available data had on global results.

Significant analysis of risk of bias was performed utilizing the Cochrane risk-of-bias tool to analyze risk of bias and ensure the studies did not demonstrate selective outcome reporting, which met the criteria that there would be no bias based on blinding, allocation concealment, sequence generation, and outcome data completeness. This study included only RCTs to reduce the risk of study selection bias. However, since only studies published in the English language were included, we cannot rule out language bias. Finally, because only statistically significant results are more likely to be published, it can still be a problem of publication bias. The systematic review was conducted with a broad search strategy, followed by a reference review of included studies to address potentially omitted relevant studies. Potential solutions Despite the above measures, there could still be the problem of missing data, underreporting or overreporting, and to deal with that, the below measures can be adopted. Hence, it would be necessary for future studies to extend the current one by including more high-quality RCTs, encompassing studies published in other languages, and searching for unpublished sources of data.

Statistical Analysis

Cochrane Review Manager 5.3 was used to perform a meta-analysis of the selected studies. For dichotomous outcomes, the pooled OR with 95% CI is given among groups. While mean difference (MD) was used for continuous outcomes. Random mode was used in order to reduce heterogeneity. The heterogeneity assumption was checked using the I² test. A leave-one-out sensitivity test was applied to solve any resulting heterogeneity. In terms of values, we interpreted the I-square as follows: not significant for 0-40%, moderate heterogeneity for 30-60%, and substantial heterogeneity for 50-90%, following the Cochrane Handbook chapter nine. A funnel plots were used to assess publication bias.

Data Collection

A comprehensive search of three databases (PubMed, Web of Science, and Cochrane) until 2^nd Nov. 2024 yielded 480 studies. After removing duplicates, thirty-six studies were available for the Title and abstract screening phase. Subsequently, a full text screening was done on 14 studies. Finally, six randomized controlled trials have met our inclusion criteria (Figure 1).

Characteristics of Included Studies

Total six randomized controlled trials were included in our meta-analysis in the form of two comparison groups (Medical vs Surgical approaches) and (Tightrope fixation vs other surgeries). The total number of patients are 164 in the first group and 181 patients in the second group. The summary features of the included studies can be found in (Table 1). Moreover, the baseline characteristics of the encompassed studies are available in (Table 2).

Primary outcome

Constant score (Functional outcome)

Surgical vs non-surgical approach in acromioclavicular joint dislocation type III: The pooled mean difference showed a lower achieved constant score in the surgical group compared to the non-surgical group [MD= -0.24 [-4.49, 4.00] 95% CI]. However, no significant statistical difference was reported between the surgical and non-surgical groups [P= 0.91] (Figure 2). The pooled result was heterogeneous (I²= 55%, P= 0.11). Hence, a sensitivity test is conducted and reduces the heterogeneity after excluding Joukainen et. al. 2014 (I²= 46%, P= 0.17) (Figure 3). A funnel plot of constant score in the surgical group compared to the non-surgical group is shown in (Figure 4).

Different Surgical approaches (Tightrope fixation vs other surgeries) in acromioclavicular joint dislocation type III

The pooled mean difference showed a higher constant score in the tightrope group compared to the other surgeries group [MD=8.34 [5.67, 11.02] 95% CI]. A significant statistical difference was noted between the Tightrope fixation and other surgical procedures [P< 0.00001]. The pooled result was homogenous (I²= 0%, P= 0.48) (Figure 5). A funnel plot of constant score in the tightrope group compared to the other surgeries group is shown in (Figure 6).

Figure 1: PRISMA flow diagram, PRISMA: Preferred Reporting Items for Systematic Review and Meta-Analysis

Table 1: Summary of the included studies

Table 1: Continue

RCT: Randomised Controlled Trial; ACJ: Acromioclavicular Joint; UCLA: University of California at Los Angeles Shoulder Rating Scale; SST: Simple Shoulder Test; AC: Acromioclavicular; NA: Not Applicable; CC: Coracoclavicular; TR: TightRope; BS: Bosworth screw; DASH: Disabilities of the Arm, Shoulder and Hand; MRI: Magnetic Resonance Imaging

Table 2: Baseline Characteristics of Participants

SD: Standard Deviation; NA: not applicable

Figure 2: Forest plot illustrating Constant Score Comparison – Surgical vs. Non-Surgical

Figure 3: Forest plot shows the Sensitivity Analysis for Constant Score Outcomes

Figure 4: Funnel plot of constant score in the surgical group compared to the non-surgical group

Figure 5: Forest plot illustrating Constant Score Comparison – Tightrope Fixation vs. Other Surgical Techniques

Figure 6: Funnel plot of constant score in the tightrope group compared to the other surgeries group

Secondary outcomes

Joint displacement distance (Postoperative joint stability)

Different Surgical approaches (Tightrope fixation vs other surgeries) in acromioclavicular joint dislocation type III: In 2 out of 3 studies, The pooled mean difference showed a lower postoperative joint stability in the tightrope group compared to the other surgeries group [MD= -2.15 [-5.89, 1.59] 95% CI]. There was no significant statistical difference between the Tightrope fixation and other surgical procedures groups in the joint displacement distance outcome [P= 0.26]. Remarkably, the pooled result was homogenous (I²= 0%, P= 0.35) (Figure 7). A funnel plot of postoperative joint stability in the tightrope group compared to the other surgeries group is shown in (Figure 8).

Figure 7: Forest plot of Postoperative Joint Displacement – Tightrope vs. Other Surgical Approaches

Figure 8: Funnel plot of postoperative joint stability in the tightrope group compared to the other surgeries group