Acromioclavicular joint (ACJ) dislocation is a common shoulder injury, particularly among young and physically active individuals, and predominantly results from sports-related trauma or a direct impact. Epidemiological data indicate that ACJ injuries account for approximately 9–12% of all shoulder injuries, occurring most frequently in young male athletes [1]. The estimated incidence is roughly 1.8 per 10,000 individuals globally, with a strong association with contact sports such as rugby and hockey [2, 3].

Radiographic and clinical assessment commonly follows the Rockwood classification system, where higher injury grades such as III, IV, V, and VI indicate increasing vertical and/or horizontal instability [4]. For Rockwood type III injuries, surgical fixation is often recommended, particularly in patients with significant instability or high functional demands, although the optimal surgical strategy for managing these injuries remains a point of debate [5]. Traditional clavicular hook plate can restore joint alignment by immediate reconstruction of the acromioclavicular relationship [6], but multiple studies report several complications, including subacromial impingement, bony changes of the distal clavicle or acromion, persistent discomfort, and a frequent need for implant removal [7, 8].

Arthroscopic TightRope fixation, a minimally invasive approach, has emerged as a promising option due to its preservation of acromial anatomy and lack of routine implant removal [9]. Compared with hook plate fixation, TightRope approach demonstrates shorter incision, less intraoperative blood loss, and alleviated postoperative pain assessed through visual analog scale (VAS), with postoperative functional outcomes by American Shoulder and Elbow Surgeons (ASES), Constant–Murley, and University of California, Los Angeles (UCLA) scores that are comparable or often better, whereas overall complication rates, such as infection and reoperation, are considerably lower [10, 11, 12]. A meta-analysis indicates that while differences in VAS, Constant–Murley scores, and coracoclavicular distance (CCD) restoration are often small, the TightRope approach effectively reduces the likelihood of reoperations and subacromial bony changes [10].

Despite extensive advances in surgical approach-related investigations, integrated assessments examining radiographic reduction quality, functional recovery, and risk factors for postoperative complications remain limited. To our knowledge, there is limited evidence on combining clinical and imaging variables to develop predictive models for individualized risk assessment before surgery.

Therefore, this study compares the efficacy and safety of arthroscopic TightRope with conventional hook plate fixation, identifies independent risk factors that shape postoperative complications and functional outcomes, and develops a complication-prediction model integrating clinical variables with radiographic indices. The study aims to provide practical, evidence-based guidance for surgical decision-making and perioperative management in patients with Rockwood III acromioclavicular (AC) dislocations.

This study compared minimally invasive fixation techniques for ACJ dislocation: TightRope suspension and clavicular hook plate. At 6 months postoperatively, TightRope showed better radiographic outcomes—improved CCD, ACD, ACI, and implant stability—suggesting superior biomechanical performance. Patients in the TightRope group also had higher functional scores (ASES, Constant–Murley, and UCLA), along with lower VAS pain. The overall incidence of complications was lower with TightRope than with the hook plate. Multivariate analysis identified fixation methods, intraoperative trauma, and implant displacement as independent predictors of recovery and stability, while fixation type, postoperative ACD, and intraoperative blood loss independently predicted complications. A risk predictive model incorporating these factors performed well in both the training (AUC = 0.84) and validation (AUC = 0.76) sets, with good calibration and clinical utility.

Clavicular hook plates offer rigid fixation by anchoring beneath the acromion and acting as a mechanical lever to maintain joint reduction [21]. Although effective at restoring vertical alignment, the hook inevitably exerts pressure on the subacromial space, which may lead to persistent impingement of surrounding soft tissues. Prolonged implant retention increases the risk of complications such as subacromial impingement and humeral head osteolysis [22, 23]. Therefore, early removal of the hook plate is often recommended after fracture or dislocation healing to minimize these risks [24].

In contrast, the TightRope system establishes a dynamic, suture-based suspension between the coracoid and clavicle, mimicking the function of the native coracoclavicular ligaments while preserving joint mobility [25, 26]. Because it avoids rigid metal intrusion into the joint space, it better maintains physiological kinematics and reduces the likelihood of mechanical irritation of the acromion. This dynamic fixation system also allows controlled micromotion, which may favor a more natural stress distribution during shoulder movement.

In the current study, the TightRope group achieved smaller CCD, ACD, and implant migration, reflecting comparable—if not superior—joint alignment relative to hook plate fixation. Previous biomechanical and clinical studies also support the ability of the TightRope construct to restore coracoclavicular stability [27]. While potentially offering less rigid fixation than metal plates, the TightRope system’s soft tissue–preserving design and dynamic-loading properties may yield superior functional stability.

Our findings align with previous evidence indicating better pain control and functional recovery with the TightRope approach. Wang et al. [28] observed significantly lower VAS scores and higher Constant–Murley scores in the TightRope group compared to the hook plate group at both 6 and 12 months postoperatively. A meta-analysis by Pan et al. [29] involving 179 patients with Rockwood type III–IV dislocations also reported substantially lower postoperative VAS scores in the TightRope group, although Constant–Murley or UCLA scores were comparable between the two groups. Likewise, a randomized controlled trial by Cai et al. [30] reported smaller incisions, reduced intraoperative blood loss, and significantly lower VAS scores at postoperative day 1, 3 months, and 12 months with TightRope; Constant–Murley scores or coracoclavicular distances at 12 months did not differ.

Multivariable regression revealed intraoperative blood loss as an independent predictor of postoperative complications (OR = 1.86, p = 0.017), indicating that greater blood loss increases the risk of adverse outcomes, likely reflecting the extent of surgical trauma and soft tissue injury, which can impede recovery. In contrast, although longer incision length was associated with higher complication risk in univariate analysis (p = 0.009), it was not statistically significant after adjustment (p = 0.322). This suggests that once intraoperative blood loss and implant stability are considered, the independent effect of incision length on complications is limited.

Considering the minimally invasive nature of TightRope fixation—smaller incisions, reduced tissue trauma, and minimal subacromial irritation—our findings highlight the importance of operation type and blood loss control in optimizing postoperative recovery. TightRope preserves soft tissue integrity and avoids direct mechanical stimulation of the acromion. In contrast, hook plate fixation often requires secondary removal due to chronic foreign-body irritation, and it can limit shoulder motion postoperatively, potentially delaying functional recovery [31]. Overall, TightRope fixation provides stable joint reduction while preserving joint mechanics, which supports superior functional outcomes.

In this study, overall complication rates were lower with TightRope than with hook plate fixation. The incidence of infection was relatively low in both groups. Other complications tended to occur less often after TightRope, although several differences were not statistically significant. Wang et al. [28] reported three cases of subacromial impingement, two cases of post-traumatic arthritis, and two wound infections in the hook plate cohort, versus one reduction failure in the TightRope group. Lin et al. [32] demonstrated that hook plate fixation can induce rotator cuff injury and subacromial impingement, leading to decreased functional scores. Our statistical analyses similarly confirmed the influence of operation type on complication risk: hook plate fixation is associated with implant tip irritation and a higher likelihood of secondary procedures, and suboptimal reduction or implant displacement increases the risk of recurrent dislocation, though re-dislocation rates did not differ significantly in our cohort.

Multivariate logistic regression identified operation type, immediate postoperative ACD, and intraoperative blood loss as independent predictors of complications. These results underscore the need for an optimal reduction and a carefully selected fixation method to minimize postoperative risk. A meta-analysis by Pan et al. [29] found no statistically significant difference in overall complication rates between the two techniques; that conclusion may be limited by heterogeneity in study design and definitions of complications. Overall, TightRope has advantages in terms of reduced surgical trauma and improved functional recovery. The trend of lower frequency of certain complications is consistent with the theoretical mechanism of avoiding mechanical damage to bones and soft tissues at the acromial hook.

Additionally, we developed and validated a complication risk prediction model incorporating surgical method, immediate postoperative ACD, and intraoperative blood loss. The model demonstrated robust discriminative power (AUC = 0.76–0.84) and favorable calibration (Hosmer-Lemeshow, p $>$ 0.05). Clinically, this model can facilitate preoperative patient counseling and guide perioperative planning by identifying high-risk individuals, thereby improving perioperative care and enhancing postoperative recovery. Linear regression analyses further showed that the surgical approach, intraoperative blood loss, and degree of implant migration significantly influenced both postoperative CCD restoration and shoulder function. Lower intraoperative trauma was associated with better anatomical reduction, likely through reduced postoperative inflammation. Implant stability was particularly critical: each 1 mm increase in implant displacement was associated with an approximately 1.8-point decrease in the Constant–Murley score ($\beta$ = –1.77), highlighting the clinical importance of minimizing postoperative implant migration.

Overall, these results suggest that TightRope fixation provides robust stability and potential for functional recovery in Rockwood III acromioclavicular joint dislocations, with lower complication rates. Given its minimally invasive profile, biomechanical advantages, and favorable patient recovery, TightRope represents a reasonable option for selected patients. However, further high-quality randomized controlled trials (RCTs) are needed to confirm their efficacy in reducing re-dislocation and overall complication rates. Treatment should remain individualized based on patient age, bone quality, economic considerations, and activity level. Postoperative management should emphasize monitoring for implant displacement and early functional rehabilitation to maximize outcomes and minimize long-term disability.

Despite compelling findings, we acknowledge several limitations. This is a single-center, retrospective cohort design with non-randomized treatment allocation, which introduces potential selection bias. Although we adjusted for known confounders such as operation type, intraoperative blood loss, and ACD, unmeasured variables (e.g., surgeon experience, soft tissue quality, and adherence to rehabilitation) may have affected outcomes. Additionally, the sample size is relatively modest and obtained from a single institution, limiting the external validity and generalizability of our findings.

To validate these findings regarding outcomes and complication risk, larger multicenter prospective randomized controlled trials (RCTs) are warranted. Long-term follow-up is also needed to assess implant durability, sustained functional recovery, and late complications. Another promising direction involves cost-effectiveness analyses to quantify the economic benefits of minimally invasive techniques such as TightRope, particularly the potential reduction in complication rates, rehabilitation duration, and overall healthcare utilization. Furthermore, future investigations should also explore the role of TightRope in higher-grade dislocations (e.g., Rockwood type V–VI), especially after high-energy trauma or when additional ligamentous injuries occur. Finally, combining TightRope with dual-suspension constructs or augmentation materials to enhance fixation strength and clinical outcomes also warrants further investigation.

This study supports the minimally invasive TightRope suspension as a biomechanically favorable, tissue-preserving alternative for managing Rockwood type III ACJ dislocations. It appears particularly suitable for patients with high functional demands or those seeking to minimize the risk of reoperation. The improvements demonstrated in stability and functional recovery highlight the clinical potential of soft-fixation strategies in managing ACJ injury. The complication risk prediction model provides a quantitative tool for individualized preoperative risk assessment and facilitates more informed surgical planning. With future validation through multicenter cohorts and cost-effectiveness analyses, the TightRope system could be adopted as a standardized, cost-effective treatment strategy that guides clinical protocols and insurance reimbursement frameworks.

• TightRope fixation demonstrated minimally invasive advantages, including shorter incision length, reduced intraoperative blood loss, and lower complication rates compared with hook plate fixation.

• Radiographic outcomes in 6 months showed superior ACJ stability in the TightRope group, with significantly improved CCD, ACD, and ACI values.

• Functional recovery was better in the TightRope cohort, evidenced by higher ASES, Constant–Murley, and UCLA scores, alongside lower VAS pain levels.

• Multivariable linear regression identified operation type, intraoperative blood loss, and implant displacement as key predictors of radiographic and functional outcomes.

• Logistic regression analysis identified TightRope fixation as an independent protective factor against complications, while greater blood loss and larger ACD were independent risk factors.

• The complication prediction model demonstrated strong discrimination, calibration, and clinical utility, with consistent performance in both the training and validation sets.

The data analyzed during the current study are available from the corresponding author upon reasonable request.

YJY contributed to conceptualization, methodology, formal analysis, writing–original draft, and visualization. RX was involved in data curation and investigation. SLH contributed to data curation, software, and validation. YHL participated in data curation and investigation. TJM was responsible for data curation, resources, and validation. HRCZ contributed to investigation and visualization. HZ was involved in investigation and resources. ZJJ contributed to investigation and validation. HXS contributed to resources and validation. FY contributed to conceptualization, project administration, and supervision. All authors contributed to revising the manuscript critically for important intellectual content. All authors approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

The study was approved by the Ethics Committee of Tongliao People’s Hospital (approval number: TLPH-EC-2025-69). As the analysis used existing medical records of the patients and presented no risk, the institutional ethics committee granted a waiver of informed consent. This study was conducted in accordance with the principles outlined in the Declaration of Helsinki.

Not applicable.

This research received no external funding.

The authors declare no conflict of interest.