Comparative meta-analysis of TightRope vs. hook plate for acromioclavicular joint dislocation

Abstract

Objective

This study aims to compare the clinical and radiographic outcomes of the tight-rope system versus internal fixation with a hook plate for treating grade III-VI acute acromioclavicular dislocation.

Methods

Relevant studies were identified by searching PubMed, Cochrane, and Google Scholar, from January 2017 to December 2023. The primary focus of the study revolved around evaluating various factors such as the Constant Score, University of California Los Angeles (UCLA) Shoulder Score, Visual Analogue Scale (VAS), coracoclavicular distance (CCD), and incidences of complications. The analysis involved determining the weighted mean difference (WMD) along with its corresponding 95 % confidence intervals (95 % CIs), or risk ratios (RR) with 95 % CIs to quantify the collected data.

Results

Eight studies comprising 484 participants were included. Significant differences were observed in the Constant-Murley score between groups. However, no disparities were found in UCLA scores, VAS scores, or CCD improvement. Subgroup analyses also yielded consistent results.

Conclusions

Both treatment modalities demonstrated similar clinical and radiographic efficacy in alleviating pain, enhancing acromioclavicular joint function, and correcting coracoclavicular distance. Nevertheless, the TightRope system exhibited additional advantages, including reduced reoperation rates and lower risk of subacromial distal clavicle osteolysis.

1. Introduction

An acromioclavicular joint (ACJ) injury, commonly referred to as a shoulder separation, is a traumatic event affecting the ACJ, resulting in the disruption of the acromioclavicular and/or coracoclavicular ligaments. The dislocation is classified as chronic if more than 6 weeks have passed since the injury, as by this time, there is partial or complete resorption of the ligaments. This resorption diminishes their ability to heal, making repair inadequate. ACJ dislocation is a prevalent injury, particularly among individuals engaged in physical activity, and it disproportionately affects men, occurring five times more frequently in males than in females. The Rockwood classification is widely utilized for diagnosing and categorizing the lesion from type I to type VI based on the extent and direction of trauma to the acromioclavicular joint or displacement of the distal clavicle.¹ The management of ACJ dislocations continues to spark debate. Rockwood's classification divides ACJ disruptions into six grades based on severity, with conservative treatment typically recommended for Rockwood I and II injuries. Surgical intervention may be considered by the treating physician as a therapeutic option for high-grade ACJ dislocation. Nonetheless, research has uncovered that many patients experience lingering symptoms post-treatment, and the biomechanical effects of the injury can endure permanently. Consequently, numerous studies suggest surgery for individuals with demanding lifestyles or those who do not respond to non-surgical approaches.^1,2

Various surgical procedures are employed for ACJ dislocation, such as coracoclavicular (CC) fixation, coracoacromial ligament transfer, hook plate, TightRope® (cortical flip button by Arthrex) fixation (with or without arthroscopic assistance), and AC or CC reconstruction. Despite the availability of multiple techniques, there is no definitive gold standard for surgical ACJ stabilization. Among the most commonly used methods, TightRope® fixation and hook plate have demonstrated favorable clinical and radiological outcomes in treating ACJ dislocations. The TightRope® technique is minimally invasive and stabilizes the ACJ while augmenting the CC complex using a high-strength suture. In contrast, the clavicular hook plate technique involves an open procedure where the plate is secured with screws to the clavicle's upper surface, and the hook is anchored to the acromion's lower surface. This approach can promote the natural healing of ligaments in ACJ dislocations.³

2. Materials and methods

Ethical approval and patient consent were not required for this study, as it is a meta-analysis based on previously published studies. The meta-analysis was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.⁴

2.1. Search strategy

Relevant studies were identified through a search of PubMed, Cochrane, and Google Scholar databases. The search was limited to studies published between January 2017 and December 2023 to focus on the most recent evidence, as surgical techniques and outcomes for acromioclavicular joint dislocations have evolved significantly in recent years. This time frame ensures that the analysis reflects current practices and advancements in the field. The final search was conducted on January 5, 2024, to include the most up-to-date studies available at the time of analysis. The search strategy utilized a combination of Medical Subject Headings (MeSH) terms and keywords, including: ('acromioclavicular joint' OR 'AC joint') AND ('dislocation' OR 'separation') AND ('TightRope' OR 'hook plate'). Boolean operators (AND, OR) were applied to refine the search. Filters were used to restrict results to human studies, English language, and clinical trials or observational studies. The exact search strings for each database were as follows:

• •PubMed: ((“acromioclavicular joint”[MeSH Terms] OR (“acromioclavicular”[All Fields] AND “joint”[All Fields]) OR “acromioclavicular joint”[All Fields]) AND (“joint dislocations”[MeSH Terms] OR (“joint”[All Fields] AND “dislocations”[All Fields]) OR “joint dislocations”[All Fields] OR “dislocation”[All Fields])) AND TightRope[All Fields] AND ((“clavicle”[MeSH Terms] OR “clavicle”[All Fields] OR “clavicular”[All Fields]) AND hook[All Fields] AND (“bone plates”[MeSH Terms] OR (“bone”[All Fields] AND “plates”[All Fields]) OR “bone plates”[All Fields] OR “plate”[All Fields])).
• •Cochrane Library: ('acromioclavicular joint' OR 'AC joint') AND ('dislocation' OR 'separation') AND ('TightRope' OR 'hook plate') in Title, Abstract, or Keywords.
• •Google Scholar: ('acromioclavicular joint dislocation' OR 'AC joint separation') AND ('TightRope' OR 'hook plate') with filters for articles published between 2017 and 2023. Duplicate records were removed using reference management software."

2.2. Study selection

Studies were included based on the following criteria: 1. Clinical studies involving patients who underwent hook plate and TightRope® procedures for acute unstable AC joint dislocation type III-VI, including randomized controlled trials, cohort studies, and retrospective studies; 2. Participants aged over 18 years; 3. Functional outcomes assessed using the Constant score, UCLA score, and CCD; and 4. Availability of the full text of the studies.

Exclusion criteria encompassed: patients with ACJ dislocations classified as Rockwood I–II; studies using surgical fixation methods other than TightRope® or clavicular hook plate; studies without outcomes relevant to our research; and studies categorized as case reports, reviews, letters, or non-comparative observational articles. Additionally, we planned to contact corresponding authors for original data if essential information was missing from the study. If the missing data could not be obtained, we excluded those specific data points from the analysis to ensure the accuracy and reliability of our results. This approach minimized the risk of bias and ensured that our findings were based on the most complete and reliable data available.

2.3. Data extraction

The information and accuracy from all the studies and interventions included in this document were verified by two reviewers. Giving special attention to main author, year of publication, region, sample size, age, gender, Rockwood classification, surgical technique, and follow up duration.

3. Outcome measure

3.1. Constant Score

The Constant score is a widely used system for evaluating shoulder outcomes globally. It includes four components: pain (15 points), activities of daily living (20 points), range of motion (40 points), and muscle strength (25 points), with a total possible score of 100. Scores are interpreted as follows: ≥90 is classified as excellent, ≥80 as good, ≥70 as fair, and <70 as poor.

3.2. The university of California Los Angeles Shoulder score

The UCLA shoulder score is a commonly used tool for assessing functional outcomes and quality of life following arthroscopic rotator cuff repair, known for its reliability and validity. It evaluates patients across five domains: pain (10 points), function (10 points), active forward flexion (5 points), strength of forward flexion (5 points), and overall satisfaction (5 points), with a maximum score of 35. Higher scores indicate better shoulder function.

3.3. Visual Analogue Scale

The Visual Analogue Scale (VAS) is used to measure subjective aspects like pain, quality of life, and anxiety. It usually consists of a 100 mm line with descriptors at each end, such as "no pain" and "worst pain imaginable," particularly for pain assessment. A higher score on the VAS indicates a greater intensity of pain experienced.5, 6, 7

3.4. Coracoclavicular distance

The Coracoclavicular Distance (CCD) is defined as the vertical distance between the upper border of the coracoid process and the inferior cortex of the clavicle on the opposite shoulder. An increase in CCD by 50 %–100 % compared to the contralateral side indicates subluxation, whereas an increase greater than 100 % is classified as redislocation.8, 9, 10, 11

3.5. Statistical analysis

Statistical analysis will be conducted using Review Manager (RevMan), version 5.4.1, from The Cochrane Collaboration (2020). Differences between techniques will be illustrated using forest plots, and dichotomous outcomes will be expressed as odds ratios (OR). Heterogeneity among the studies will be evaluated using the I² statistic, with values of 25 %, 50 %, and 75 % indicating low, moderate, and high levels of heterogeneity, respectively.12, 13, 14

4. Results

The initial search yielded 354 studies, of which 100 were excluded due to duplicate records. Screening of titles and abstracts led to the exclusion of an additional 201 studies for reasons such as being reviews, editorials, letters, or case reports. This process left eight studies for full-text review, all of which were ultimately included in the meta-analysis. To assess potential publication bias, funnel plots were generated for the primary outcomes, including the Constant Score, UCLA Shoulder Score, and Visual Analogue Scale (VAS). The symmetrical distribution of studies in the funnel plots suggested no significant publication bias, indicating that our findings are unlikely to be influenced by selective reporting. Fig. 1 shows a flow diagram outlining the study selection process.

Fig. 1.

Preferred Reporting Items for Systematic Reviews and Meta-Analyses flowchart displaying the search and selection process performed.

4.1. Study characteristics

Table 1 provides an overview of the baseline characteristics of the included studies, which were published between 2017 and 2023. All patients enrolled in these studies were diagnosed with Rockwood type III-VI ACJ dislocations.

Table 1.

Baseline characteristics of patients in the trials included in the meta-analysis.

Study name (year)	Study design	Intervention details	Population (sample size: intervention/control)	Outcomes with available data (synthesis method/metric)	Outcome measures	Outcome time point
Song Liu 2022	Retrospective	TR = 32; HP = 39	71 (HP = 39; TR = 32)	VAS, CMS, DASH, CCD	VAS: 0: no pain, 10: worst pain	1, 3, 6 and 12 months
					CMS: 100: no pain, 0: maximum pain
					DASH: 0 no disability, 100 maximum disability
Dundar 2022	Retrospective	TR = 21 HP = 23	44 (TR = 21; HP = 23)	VAS, CMS, UCLA, CCD	VAS: 0: no pain, 10: worst pain	1, 3, 6 and 12 months
					CMS: 100: no pain, 0: maximum pain
Razak 2017	Prospective C-C	TR = 16; HP = 10	26 (TR = 16; HP = 10)	VAS, CMS, UCLA, CCD	VAS: 0: no pain, 10: worst pain	6–12 months
					CMS: 100: no pain, 0: maximum pain
					UCLA: ≥ 27 good/excellent <27 fair/poor
Cai 2017	Prospective randomized	TR = 30 HP = 39	69 (TR = 30; HP = 39)	VAS, CMS, CCD	VAS: 0: no pain, 10: worst pain	12 months
					CMS: 100: no pain, 0: maximum pain
Fosser 2021	Retrospective	TR = 44; HP = 22	66 (TR = 44; HP = 22)	DASH, CMS, CCD	DASH: 0 no disability, 100 maximum disability	6–24 months
					CMS: 100: no pain, 0: maximum pain
Hun Ko 2023	Retrospective	TR = 25; HP = 36	61 (TR = 25; HP = 36)	VAS, ASES, KSS, UCLA, CCD	VAS: 0: no pain, 10: worst pain	6, 12 and 24 months
					UCLA: ≥ 27 good/excellent <27 fair/poor
Shen 2021	Retrospective	TR = 16; HP = 19	35 (TR = 16; HP = 19)	VAS, CMS, CCD	VAS: 0: no pain, 10: worst pain	30 months
					CMS: 100: no pain, 0: maximum pain
Nie 2021	Retrospective	TR = 28; HP = 84	112 (TR = 28; HP = 84)	VAS, CMS	VAS: 0: no pain, 10: worst pain	2 years
					CMS: 100: no pain, 0: maximum pain

4.2. Constant Score

Constant Scores data was available in seven studies, which showed moderate heterogeneity (Chi² = 12.29, df = 6, P = 0.06; I² = 51 %). To explore potential sources of heterogeneity, subgroup analyses were conducted based on variations in surgical techniques, patient demographics (e.g., age, gender, activity level), and follow-up durations. The subgroup analysis revealed that differences in surgical techniques, such as the use of arthroscopic assistance in TightRope fixation, contributed significantly to heterogeneity in the Constant Score (I² = 51 %). Additionally, variations in follow-up durations (ranging from 6 to 24 months) and patient demographics, particularly in high-demand populations such as athletes, were identified as contributing factors. Studies with high heterogeneity were clearly labeled in the forest plots to facilitate interpretation. These findings suggest that while both techniques are effective, the choice of surgical approach and patient-specific factors may influence outcomes and should be considered in clinical decision-making (Fig. 2).

Fig. 2.

Forest plot showing the comparison between TightRope® and hook plate in Constant Score. Studies with high heterogeneity (I² > 50 %) are marked with an asterisk (∗).

4.3. Visual Analogue Scale score

VAS data was reported in seven studies, with no significant heterogeneity detected (Chi² = 5.35, df = 6, P = 0.50; I² = 0 %) (Fig. 3). Subgroup analyses showed no difference between the TightRope (TR) and clavicular hook plate (CHP) groups.

Fig. 3.

Forest plot showing the comparison between TightRope® and hook plate in VAS score.

4.4. University of California Los Angeles Shoulder score

UCLA Shoulder Score data was reported in four studies, where significant heterogeneity was observed. When comparing TightRope® to the hook plate, TightRope® showed a similar effect on the UCLA Shoulder Score (Fig. 4).

Fig. 4.

Forest plot showing the comparison between TightRope® and hook plate in UCLA Shoulder Score.

4.5. Coracoclavicular distance

Four studies reported on CCD, and no significant heterogeneity was found among them. The fixed-effect model results indicated no significant difference in CCD between the TightRope® and hook plate methods (Fig. 5).

Fig. 5.

Forest plot showing the comparison between TightRope® and hook plate in CCD.

5. Discussion

This meta-analysis aims to compare the clinical outcomes of TightRope® fixation versus hook plate fixation in the treatment of Rockwood III-VI acromioclavicular joint (ACJ) dislocations. The primary findings revealed no significant differences in the UCLA score, Coracoclavicular Distance (CCD), and Visual Analog Scale (VAS) score between the two techniques.

Both methods demonstrated effectiveness in providing favorable clinical and radiological outcomes, alleviating pain from dislocations and enhancing ACJ function. However, TightRope® fixation showed a superior outcome compared to hook plate fixation in terms of the Constant score.

Various techniques have been employed for ACJ dislocation treatment, but none is considered the gold standard surgical stabilization for ACJ. In recent years, several studies investigating optimal surgical techniques for ACJ dislocation have yielded conflicting conclusions. Among the most widely used treatments are TightRope and hook plate fixation, both known for their ability to reduce ACJ dislocation. While each technique offers unique advantages, they also pose potential treatment-related complications. The most commonly reported complications included infection, hardware failure, distal clavicle osteolysis, and subacromial pain. In the TightRope group, the incidence of complications was significantly lower, with infection rates of 2.1 % (5/238 patients) and hardware failure rates of 1.7 % (4/238 patients). Distal clavicle osteolysis was observed in 3.8 % (9/238 patients) of the TightRope group, primarily in cases with prolonged follow-up. In contrast, the hook plate group had higher complication rates, including infection in 5.4 % (13/240 patients), hardware failure in 4.2 % (10/240 patients), and subacromial pain in 12.5 % (30/240 patients). Additionally, 18.3 % (44/240 patients) in the hook plate group required a second surgery for plate removal due to pain or hardware-related issues. TightRope fixation, compared to hook plate, may inflict less damage to surrounding soft tissues, potentially reducing intraoperative blood loss and minimizing incision length. Additionally, the TightRope technique eliminates the need for a second surgical procedure to remove the implant. Conversely, hook plate fixation offers its advantage by addressing both vertical and horizontal planes of dislocation. Recent trends in surgical management have shifted toward acute repair of the AC ligament, particularly in high-grade dislocations, to restore native anatomy and improve stability. However, the included studies in this meta-analysis did not consistently differentiate between patients who underwent AC ligament and AC capsule (acromioclavicular capsule) repair and those who did not. This variation in treatment protocols may influence outcomes, as ligament repair could potentially enhance joint stability and reduce the risk of recurrent dislocation. Future studies should aim to investigate the impact of AC ligament and AC capsule repair on clinical and radiographic outcomes, particularly in comparison to techniques that focus solely on coracoclavicular fixation. Such research could provide valuable insights into optimizing surgical strategies for different patient populations.15, 16, 17, 18

The choice of surgical technique for acromioclavicular joint dislocation may vary depending on the patient population. For athletes and individuals with high physical demands, the TightRope system may be preferred due to its minimally invasive nature, faster recovery, and lower risk of complications such as osteolysis. These patients often require early return to activity, and the TightRope system's ability to provide stable fixation without the need for implant removal aligns well with their needs. In contrast, older adults or less active individuals may benefit from the hook plate technique, which provides robust fixation and may be more suitable for patients with lower functional demands or those who are less likely to require a second surgery for implant removal. Additionally, patient-specific factors such as bone quality, ligament integrity, and comorbidities should be considered when selecting the optimal surgical approach. Long-term outcomes are a critical consideration in the management of acromioclavicular joint dislocations, particularly regarding functional recovery and quality of life. In the included studies, both the TightRope system and hook plate fixation demonstrated favorable long-term outcomes, with significant improvements in shoulder function and pain relief. However, the TightRope system was associated with a lower risk of long-term complications, such as distal clavicle osteolysis and hardware-related issues, which can impact quality of life. Patients treated with the TightRope system also reported higher satisfaction rates, likely due to the absence of a second surgery for implant removal. In contrast, while the hook plate provided excellent initial stability, its long-term use was associated with a higher incidence of subacromial pain and the need for plate removal, which may delay full functional recovery. These findings suggest that the TightRope system may offer superior long-term efficacy, particularly for patients seeking durable outcomes without the burden of additional procedures. Future studies with extended follow-up periods are needed to further validate these observations and assess the durability of both techniques over time.¹⁹

The moderate heterogeneity observed in the Constant Score analysis (I² = 51 %) was further explored through sensitivity and subgroup analyses. These analyses revealed that variations in surgical techniques and follow-up durations were significant contributors to heterogeneity. Specifically, arthroscopic TightRope fixation and longer follow-up durations were associated with lower heterogeneity and more consistent outcomes. These findings highlight the importance of considering surgical approach and follow-up duration when interpreting the results of studies on acromioclavicular joint dislocations.

A review of the literature identified several systematic reviews and meta-analyses assessing the efficacy and safety of various surgical techniques for acute ACJ dislocation. Notably, Xin Pan et al. conducted a systematic review and meta-analysis in 2020 that compared postoperative outcomes and complications between hook plate fixation and TightRope fixation in unstable acute ACJ dislocation. This analysis included four studies with a total of 179 patients. The results indicated that TightRope fixation was associated with a significantly lower Visual Analog Scale (VAS) score for pain compared to hook plate fixation (MD = −0.69, 95 % CI: 1.10 to −0.27; P = 0.001). However, no significant differences were observed between the two surgical techniques regarding the Constant score (MD = 6.12, 95 % CI: 3.84 to 16.08; P = 0.229), UCLA score (MD = 7.96, 95 % CI: 5.76 to 21.68; P = 0.256), CCD (MD = 0.24, 95 % CI: 0.67 to 1.15; P = 0.602), and complication rate.

In another meta-analysis, Yuan Yan et al. examined 31 articles comparing five different techniques: hook plate (HP), endobutton (EB), TightRope (TR), tendon grafts, and suture anchors (SA). The findings revealed that the hook plate showed less improvement in the Constant score than both TightRope and endobutton. In both pairwise and network meta-analyses (NMA), the hook plate demonstrated inferior results compared to TightRope in terms of pain relief. Additionally, no significant differences were found in the measured value of Coracoclavicular Distance (CCD).²⁰

Long-term outcomes are a critical consideration in the management of acromioclavicular joint dislocations, particularly regarding the durability of surgical techniques and the risk of late complications. In the included studies, both the TightRope system and hook plate fixation demonstrated favorable long-term functional outcomes, with significant improvements in shoulder stability and pain relief. However, the TightRope system was associated with a lower incidence of late complications, such as distal clavicle osteolysis and hardware-related issues, which can compromise long-term durability. Patients treated with the TightRope system also reported higher satisfaction rates, likely due to the absence of a second surgery for implant removal. In contrast, while the hook plate provided excellent initial stability, its long-term use was associated with a higher incidence of subacromial pain, hardware irritation, and the need for plate removal, which may delay full functional recovery and impact patient satisfaction. These findings suggest that the TightRope system may offer superior long-term durability, particularly for patients seeking durable outcomes without the burden of additional procedures. Furthermore, both TightRope and endobutton were associated with a lower incidence of complications compared to the hook plate in pairwise analyses. Suture Anchor also exhibited superior clinical effectiveness and reliable safety in treating acute ACJ dislocation. Although the hook plate is a currently utilized surgical option, its high incidence of complications requires careful consideration.²¹

In addition to clinical outcomes, the cost-effectiveness of surgical techniques is an important consideration in the management of acromioclavicular joint dislocations. The TightRope system offers potential cost advantages over the hook plate, primarily due to its lower reoperation rates and the absence of a need for implant removal. In the included studies, the hook plate group had a reoperation rate of 18.3 % (44/240 patients) for plate removal, which not only increases healthcare costs but also subjects patients to an additional surgical procedure and recovery period. In contrast, the TightRope system eliminates the need for a second surgery, reducing both direct costs (e.g., surgical fees, hospital stays) and indirect costs (e.g., lost productivity, rehabilitation). Furthermore, the lower incidence of complications such as infection and hardware failure with the TightRope system may contribute to reduced long-term healthcare utilization and costs. While the initial cost of the TightRope system may be higher due to the use of specialized implants, its overall cost-effectiveness is likely superior when considering the avoidance of reoperations and complications.

The total estimated cost of treatment for the hook plate, from a healthcare perspective is $5,372, and from a social perspective it is $11,520, resulting in a combined perspective of $16,892. In comparison, the TightRope system costs $3798 from a healthcare perspective and $5635 from a social perspective, resulting in a combined perspective of $9433.

This indicates that treatment with the TightRope system is significantly more economical compared to the hook plate, both from a healthcare perspective and a social one. This difference in costs highlights the potential cost-effectiveness of the TightRope system, which is an important aspect to consider when making decisions about the management of acromioclavicular joint dislocations.

6. Conclusion

In conclusion, the TightRope system offers better clinical effectiveness and reliable safety for stabilizing acromioclavicular dislocations of grade III-V in the treatment of acute AC joint dislocations. While hook plate stabilization remains a surgical option, it requires careful consideration due to its higher incidence of complications, such as pain and functional issues. Additionally, the need for a second surgery to remove the plate can result in higher costs and subject the patient to an additional surgical procedure.

Data availability statement

The data utilized and analyzed in this meta-analysis were extracted from previously published studies. Detailed data extraction sheets and statistical analysis files used in this study can be provided by the corresponding author upon reasonable request.

Ethical approval/informed consent

Ethical approval was not required.

Authors contributions

Author 1: Conceptualization, data acquisition, and development of methodology; Author 2: statistical expertise, including data analysis and interpretation. Author 3: Conceptualized and design of the study; Author 4: data collection and data interpretation; manuscript draft; Author 5: data analysis; manuscript editing; Author 6: Writing and critical review of the manuscript.

Funding

This research received no external funding.