Current concepts in arthroscopic rotator cuff repair
Article information
Abstract
Rotator cuff repair has experience great development, transitioning from open surgical techniques to minimally invasive arthroscopic methods. This review explores its historical development, current repair techniques, biomechanical considerations, and advances in materials and biological augmentation. It also addresses strategies for managing partial-thickness and massive tears, compares single-row and double-row repairs, and highlights the importance of individualized postoperative rehabilitation. By integrating biomechanical precision with biological innovations, modern rotator cuff repair aims to improve healing rates, reduce retear risk, and optimize functional outcomes.
HISTORICAL DEVELOPMENT OF ROTATOR CUFF REPAIR
Rotator cuff repair has undergone important development during the past century, transitioning from open surgical techniques to minimally invasive arthroscopic methods. Initial treatments for rotator cuff tears focused on nonoperative methods, primarily physical therapy and pain management. In 1934, Codman first described rotator cuff pathology and introduced surgical repair as a treatment option, laying the groundwork for advances in shoulder surgery [1]. During the 1960s and 1970s, Neer identified the role of subacromial impingement in rotator cuff disease, leading to the development of open subacromial decompression as a standard surgical intervention [2]. Open rotator cuff repairs, though effective, require large incisions and are associated with prolonged recovery periods and high complication rates. The 1980s saw the advent of arthroscopic techniques. Pioneers such as Burkhart and Snyder standardized these minimally invasive methods that offered reduced postoperative pain, faster recovery times, and improved cosmetic outcomes compared with the open technique [3,4]. Arthroscopic repair techniques became increasingly popular, establishing a foundation for further innovations.
The single-row and double-row arthroscopic repair techniques were introduced in the 1990s, and focus on optimizing biomechanical strength and healing outcomes. Single-row repairs were initially favored for their simplicity, but double-row repairs demonstrated superior footprint restoration and biomechanical stability in many cases [5]. Advances in suture anchors and materials in the early 2000s further enhanced repair strength and reduced retear rates.
In recent years, biological augmentation has emerged as a promising adjunct to surgical repair. Techniques such as platelet-rich plasma (PRP) injections and stem cell therapies have been explored to enhance tissue healing, particularly in cases of large or complex tears. These developments represent a shift toward improving both structural integrity and biological healing in rotator cuff repair [6]. Challenges such as high retear rates, uncertain rehabilitation protocols, and management of massive or irreparable tears are areas of ongoing research and innovation.
CURRENT TECHNIQUES IN ROTATOR CUFF REPAIR
Rotator cuff repair encompasses a wide range of techniques, enabling personalized treatment tailored to patient pathology and surgeon preferences. Over time, these techniques have been developed from simple approaches to advanced methods that incorporate both biomechanical and biological considerations. Single-row repair is one of the most established techniques, involving the arrangement of sutures in a single horizontal row to restore the footprint of the rotator cuff. This method is relatively simple, time-efficient, and cost-effective. However, single-row repair does not fully restore the native footprint and can lead to stress concentration at the repair site [7].
Therefore, double-row repair was developed to address the limitations of single-row repair. Using two rows of sutures, this technique effectively restores the footprint and distributes stress more evenly, enhancing biomechanical stability. Double-row repair is especially advantageous for medium to large tears, with studies demonstrating improved long-term outcomes compared with single-row repair. However, it is more technically demanding, time-consuming, and expensive than the simpler single-row technique [8].
The transosseous-equivalent technique (TOE), also known as bridge repair, is a modern approach that further reduces stress on the repair site compared to standard double-row repair by adjusting the spacing of the sutures, maximizing healing of rotator cuff tissue [9]. Partial-thickness rotator cuff tears (PTRCTs) can be addressed using techniques such as margin convergence and medialized repair. Margin convergence involves approximating the free tendon edges to reduce the tear size and tension, facilitating anatomical repair. This method has demonstrated excellent clinical outcomes and healing rates [10]. Medialized repair shifts the tendon attachment medially to decrease tension at the repair site, which can be beneficial in cases with significant retraction or poor tissue quality. This approach has shown favorable mid-term outcomes in repairing large-to-massive rotator cuff tears [11].
To enhance biomechanical stability and promote biological healing, patch augmentation techniques are used. Materials such as acellular dermal matrix patches can reinforce the repair and support tissue regeneration. Clinical studies have reported significant improvements in patient-reported outcomes and increased tendon thickness with the use of bio-inductive collagen patches [12]. Modern repair techniques focus on improving mechanical strength and individualizing treatment strategies to optimize the outcomes of each patient.
SINGLE-ROW VS. DOUBLE-ROW REPAIR TECHNIQUES
The single-row and double-row suture techniques are most commonly used for rotator cuff repair, and they have distinct advantages and limitations. The choice of repair technique depends on the specific characteristics of the tear and the surgeon's preferences, and numerous studies have compared these methods in terms of biomechanical stability and clinical outcomes.
Single-row repair is a simpler technique with shorter operative times and lower technical demands than double-row repair. Sutures are arranged in a single horizontal row, and this method is suitable for small tears or cases with good tissue quality [13]. Using this technique, basic stitches such as simple sutures or mattress sutures are often outperformed biomechanically by advanced constructs such as anterior-posterior stitches or medial-lateral stitches. The rip-stop, lasso loop, modified Mason-Allen, and massive cuff stitch techniques have shown performance superior to that of simple or mattress repair constructs in resisting failure [14].
Double-row repair was developed to address the limitations of single-row repair. Double-row techniques use two rows of sutures to more effectively restore the rotator cuff footprint, enhance tendon-to-bone contact, and distribute mechanical stress evenly across the repair site. This approach has demonstrated biomechanical stability superior to that of single-row repair, particularly in terms of initial fixation strength and load-sharing properties [15].
Numerous studies have compared the clinical outcomes of single-row and double-row rotator cuff repairs, primarily focusing on healing rates and retear rates as assessed through imaging, as well as functional outcomes measured using scales such as the American Shoulder and Elbow Surgeons (ASES) score, the Constant-Murley score, the Shoulder Strength Index (SSI), and the University of California Los Angeles (UCLA) score (Table 1).
Summary of previous clinical studies of single-row versus double-row repair techniques for rotator cuff repair
Several studies have demonstrated that double-row repair offers significantly better healing rates and retear rates than single-row repair [16-18]. However, some studies reported no significant differences between the two techniques [19-21]. When Lapner et al. [22] compared their intact and retear groups at the final follow-up, they found that smaller tears and double-row sutures were associated with higher healing rates than larger tears and single-row sutures. Similarly, Plachel et al. [23] reported that, even after more than 10 years of follow-up, double-row repair showed lower retear rates and slightly superior tendon integrity than single-row repairs. Núñez et al. [24] performed a meta-analysis of randomized controlled trials and also concluded that double-row repairs offered higher healing rates and lower retear rates than single-row repairs.
Functional outcomes were compared using ASES, Constant-Murley, SSI, and UCLA scores. Interestingly, most studies found no significant differences in functional outcomes, irrespective of the healing and retear rates (Table 1). However, studies by Park et al. [18] and Ma et al. [21] reported better functional outcomes with double-row repair for large tears (>3 cm). Núñez’s meta-analysis [24] also found no significant differences in ASES and Constant-Murley scales but reported superior UCLA score for double-row repairs.
Several studies have evaluated the clinical outcomes of various double-row repair techniques. Rhee et al. [25] compared the outcomes of knotless TOE (suture bridge) repairs incorporating a medial-row Mason-Allen equivalent with those of knotted medial-row TOE repairs. They found that the knotless technique had a significantly lower retear rate of 6%, compared with 19% in the knotted group. Similarly, Ryu et al. [26] investigated the effects of adding lateral-row stitches to a standard suture bridge repair to address dog ears. This modification was shown to enhance healing rates compared with the conventional suture bridge construct. In contrast, Kim et al. [27] observed no significant differences in retear rates or clinical outcomes between the standard double-row and TOE techniques, indicating that the approaches offer comparable efficacy in certain contexts.
ADVANCES IN SUTURE ANCHORS AND MATERIALS
Early suture anchors were primarily made of metal, with titanium and stainless steel being the most common. Titanium is strong and lightweight and forms a calcium-phosphate surface layer that enhances osseointegration with minimal inflammatory response. Conversely, stainless steel anchors often cause fibrous encapsulation and inflammatory cell infiltration. Despite their rigidity and long-term use, metal anchors are associated with complications such as migration, joint cavity incarceration, cartilage damage, and imaging interference and can release metal ions into surrounding tissues [28].
Therefore, biodegradable anchors composed of materials such as poly-L-lactic acid and copolymers such as poly-lactic-co-glycolic acid have been introduced and offer better imaging compatibility and reduced need for removal. However, early biodegradable anchors, particularly those of polyglycolic acid, degraded too quickly, leading to inflammatory reactions. Modern biocomposite anchors incorporate materials such as beta-tricalcium phosphate to enhance osteoconductivity while maintaining controlled degradation. These advances allow better bone integration than was possible with metal anchors and minimize complications such as osteolysis or cyst formation while still ensuring adequate fixation during the healing process [29].
Advances in suture materials have significantly enhanced the efficacy of rotator cuff and other shoulder surgeries. Traditional monofilament sutures, such as nylon and polyester, often exhibited limitations in tensile strength and knot security that could compromise surgical outcomes. Therefore, modern sutures are made from ultra-high-molecular-weight polyethylene fibers. These sutures offer superior tensile strength and improved handling characteristics compared with earlier materials, facilitating easier knot tying and reducing tissue damage during surgery [30].
BIOMECHANICAL CONSIDERATIONS
Restoring the anatomical footprint is a cornerstone of rotator cuff repair. The goal is to re-establish tendon-to-bone contact while ensuring uniform pressure distribution for optimal healing. Compared with single-row repair, double-row repair more closely restores the anatomy of the repair site, enhancing tendon-to-bone healing. According to Kim et al. [7], double-row repair significantly improves the initial strength of the repair and reduces gap formation compared with single-row repair. Similarly, Park et al. [31] demonstrated that the transosseous tunnel rotator cuff repair technique generates significantly larger contact area and greater pressure distribution across the footprint than suture anchor techniques, suggesting that it might facilitate stronger and faster rotator cuff healing. However, although increased contact area can enhance biological healing, some studies indicate that footprint restoration alone does not guarantee superior functional outcomes [16,18].
Stress concentration is particularly pronounced at the tendon–bone interface and the suture–tendon junction, areas commonly associated with repair failures. Biomechanical analyses have shown that the single-row and double-row suture anchor techniques often generate high stress within the tendon, especially around the places where sutures pass through the tissue [32]. This stress concentration can weaken the already compromised biomechanical properties of degenerated tendons, increasing the likelihood of failure during the healing process. For instance, Cummins and Murrell [33] reported that most revision rotator cuff repairs using suture anchors failed at the tendon–suture interface, highlighting it as a critical weak point in rotator cuff repair.
Interestingly, the transosseous technique displayed a distinct stress distribution pattern [32]. Unlike suture anchors, which concentrate stress along the tendon–bursal surface, transosseous fixation localizes stress at the site where the suture passes through the bony trough. Although that suggests a lower risk of tendon–suture failure, it also indicates that the suture thread itself could be a potential weak point in this technique.
POSTOPERATIVE RETEAR ISSUES AND PREVENTION STRATEGIES
Re-tear after rotator cuff repair is a commonly reported complication, with incidence rates ranging from 13% to 94% [34]. Various risk factors contribute to retear rates, both patient factors such as age, systemic diseases, tear size, and tissue quality and the chosen surgical techniques and rehabilitation protocols. Increasing age in rotator cuff tear patients is associated with higher retear rates following rotator cuff repair. Diebold et al. [35] analyzed retear rates in 1,600 patients based on age and reported retear rates of 5% in patients younger than 50 years and 34% in patients older than 80 years.
Systemic diseases such as diabetes and hyperlipidemia also influence retear rates. In a meta-analysis of seven studies, Zhao et al. [36] reported that diabetes is a significant risk factor for retear following arthroscopic rotator cuff repair. Similarly, in a retrospective study of 85 patients, Garcia et al. [37] observed a significantly higher retear rate in patients with hyperlipidemia. In a study by Chung et al. [38], patients with osteoporosis (bone mineral density T-score <–2.5) exhibited a 7.25-fold higher rate of failure of rotator cuff repair compared with normal controls, and those with osteopenia showed a 4.38-fold higher failure rate.
Tear size and fatty infiltration also affect surgical outcomes after repair. Park et al. [39] reported 339 patients undergoing arthroscopic repair of small- to medium-sized tears and found a healing rate of 89% for tears <2 cm, whereas tears ≥2 cm had a healing rate of only 65%. Fatty infiltration of the muscle belly is an irreversible change, and grade 2 or higher fatty infiltration of the infraspinatus muscle has been associated with high retear rates.
To mitigate this risk, several technical, biological, and rehabilitation strategies have been developed. Rotator cuff healing relies on adequate mechanical stability at the repair site until the tendon-to-bone healing is complete. Double-row and TOE repairs offer biomechanical performance superior to that of single-row techniques [40]. Biomechanical studies have consistently demonstrated that double-row and TOE techniques provide greater tensile strength, load to failure, increased footprint contact area, and higher footprint pressure, as well as improved resistance to gap formation compared to single-row techniques [31]. These advantages contribute to better tendon compression and reduced stress concentration at the tendon–bone interface. The TOE repair technique was specifically developed to address issues such as tendon strangulation, impaired vascularity, and uneven load distribution between anchors. In a systematic review of 2,048 repairs, Hein et al. found significantly lower retear rates with the double-row and TOE techniques compared with single-row repairs across small (1–3 cm), medium (<3 cm), large (>3 cm), and massive (>5 cm) tears [40].
Biological approaches are intended to optimize the healing environment at the repair site and complement mechanical stability. PRP and growth factors such as bone morphogenetic proteins have been shown to promote cellular proliferation, angiogenesis, and tissue regeneration and enhance the tendon-to-bone healing process. Jo et al. [41] conducted a randomized controlled trial to evaluate the effect of PRP on retear rates following arthroscopic repair of large to massive rotator cuff tears. At a minimum follow-up of 9 months, the retear rate in the PRP group (20%) was significantly lower than that in the conventional group (55.6%). Additionally, mesenchymal stem cells (MSCs) have demonstrated potential in improving tendon integrity by facilitating tenocyte differentiation and matrix synthesis [42]. Hernigou et al. [42] studied the effects of bone marrow–derived MSCs used as a biological augmentation in rotator cuff repair. The group that received the MSCs demonstrated better healing rates and lower retear rates than the control group.
The timing of rehabilitation, particularly the initiation of motion, remains a topic of discussion. A systematic review by Saltzman et al. found no significant difference in retear rates between early and delayed motion groups following rotator cuff repair [43]. Early motion was defined as active motion within 6 weeks or passive motion within 3 weeks postoperatively, and delayed motion began no earlier than 3 weeks after surgery. However, subgroup analyses suggested that early motion might lead to significantly higher retear rates in patients with large tears (>3 cm). To balance healing and functional recovery, a 2–4-week period of immobilization, depending on tear size and tissue quality, is generally recommended [5]. Passive motion initiated within the first 6 weeks can help prevent adhesions and stiffness, and then active motion and strengthening exercises are introduced gradually, starting at 6–8 weeks.
APPROACHES TO PARTIAL AND MASSIVE TEARS
Partial and massive rotator cuff tears pose distinct challenges and require tailored surgical strategies. Advances in arthroscopic techniques and biological augmentation have expanded the therapeutic options for these types of tears, allowing improved functional outcomes and healing rates.
Partial-Thickness Tears
The advent of arthroscopy has significantly improved the diagnosis and treatment of PTRCTs. Ellman’s classification, which categorizes tears by location (articular, bursal, and intra-tendinous) and size (<3 mm, 3–6 mm, >6 mm), remains widely used, with grade 3 tears (>6 mm) often serving as the threshold for surgical intervention [44].
The treatment of PTRCTs remains controversial. Generally, conservative treatment is prioritized for tears involving less than 50% of the tendon thickness. Surgical intervention is considered for tears greater than 50% or when conservative treatment fails. Surgical options can be broadly categorized into debridement with or without acromioplasty, in situ repair, and conversion repair. For low-grade PTRCTs (<50% thickness), debridement with or without acromioplasty has been shown to yield satisfactory outcomes. Cordasco et al. [45] reported good results in patients with PTRCTs treated with debridement. However, they also suggested that bursal-sided tears have higher failure rates than articular-sided lesions and often require more aggressive interventions.
Conversion repair involves completing a PTRCT into a full-thickness defect, followed by repair using standard arthroscopic rotator cuff repair techniques. Although this approach can damage the remaining intact cuff, unlike in situ repair, it has the advantage of removing devitalized tissue. Kim et al. [27] compared repair integrity and functional outcomes after converting articular- and bursal-sided partial tears into full-thickness tears for repair. They demonstrated improved clinical outcomes (visual analog scale, UCLA, ASES, and Constant-Murley scores) in both groups, with no significant differences in retear rates [27].
In situ repairs offer the benefit of preserving the intact lateral insertion of the rotator cuff while securing the medial articular insertion. Although this approach maintains the native anatomy, it is technically more challenging to perform than conversion repair. Biomechanical studies have shown that in situ repairs provide certain mechanical advantages over conversion repairs; however, clinical studies have not demonstrated any significant differences in outcomes between the two techniques [46].
Massive Tears
Massive rotator cuff tears are frequently associated with tendon retraction, fatty infiltration, and muscle atrophy and pose significant challenges for repair. The criteria for defining a massive tear include the number of torn tendons, total length of the tear, and the amount of humeral head exposure. Schumaier et al. [47] conducted a study using the Delphi method and defined a massive rotator cuff tear as retraction of the tendons to the glenoid rim in either the coronal or axial plane and/or a tear that exposes > 67% of the greater tuberosity, as measured in the sagittal plane.
The treatment strategies for massive rotator cuff tears are less established than those for partial-thickness tears, though various approaches have been proposed. For irreparable tears, arthroscopic debridement combined with procedures such as subacromial decompression, tuberoplasty, bursectomy, and biceps tenotomy has shown favorable outcomes. In a systematic review of 16 articles involving 643 patients, Soderlund et al. [48] reported that arthroscopic debridement, when combined with those additional procedures, resulted in clinical improvement. Moreover, in low-demand patients older than 65 years, good functional outcomes were maintained at mid- to long-term follow-up.
Partial repair is another potential treatment option. Burkhart was the first to describe partial repair for massive, irreparable cuff tears, with the goal of balancing the anterior and posterior rotator cuff to restore the transverse plane force couple and thereby stabilize the glenohumeral joint fulcrum [49]. For more than 2 years, Hallock et al. [50] followed 38 patients with massive rotator cuff tears (>30 cm2 defect) who underwent partial repair. At the final 4-year follow-up, only 5% of patients had required revision surgery, and the defect size after partial repair did not correlate with the need for revision surgery.
Tendon transfer is also considered a treatment option for chronic irreparable tears. This approach aims to restore the horizontal or vertical force couple of the rotator cuff. Common options include latissimus dorsi or lower trapezius tendon transfer. Latissimus dorsi transfer has been reported since the 1990s and showed improvements in shoulder functional outcomes [51]. Lower trapezius transfer, originally developed to restore external rotation (ER) in patients with paralysis, has also demonstrated favorable outcomes in restoring shoulder function following irreparable massive tears [52].
Superior capsular reconstruction (SCR), proposed by Mihata et al. [53], is another approach; it uses autografts or dermal allografts to restore superior shoulder stability after irreparable massive tears. When the force couple is disrupted by a massive tear, superior humeral migration occurs, altering the direction of force across the shoulder joint. SCR aims to reconstruct the superior capsule to restore superior stability. The use of fascia lata grafts in SCR has demonstrated excellent clinical and structural results, with low retear rates observed during long-term follow-up.
Interposition grafting has also gained attention as a patch graft that bridges the gap between the torn tendon and the footprint to achieve a tension-free repair. Both SCR and interposition grafting attach the lateral margin of the graft to the greater tuberosity footprint. The key difference lies in the medial attachment: in interposition grafting, the graft’s medial end is attached to the torn tendon, whereas in SCR, it is fixed to the superior glenoid. Baek et al. compared SCR and interposition grafting in a meta-analysis and reported that both techniques improved clinical outcomes for irreparable massive cuff tears [54]. Although neither the ASES scores nor retear rates differed significantly between the techniques, interposition grafting showed a significantly lower complication rate than SCR.
POSTOPERATIVE REHABILITATION PROTOCOLS
Postoperative rehabilitation is a critical component in optimizing the outcomes of rotator cuff repair. Effective rehabilitation aims to protect the repair, minimize complications, and progressively restore shoulder function while respecting the healing process of the repaired tendon. A criterion-based, individualized approach that integrates evidence-based strategies is essential to ensure a balance between tissue protection and functional recovery. Rehabilitation is typically divided into three phases, progressing from protection to mobility and finally strengthening.
Phase 1: Protection and Healing (Weeks 0–6)
In the early phase, the priority is to minimize pain and inflammation while protecting the repair site. Patients are immobilized in an abduction sling for 4–6 weeks, depending on the tear size and tissue quality. Cryotherapy and anti-inflammatory measures help manage pain and swelling. Gentle passive range of motion (PROM), primarily in the scapular plane, is introduced to prevent stiffness and excessive strain on the repaired tendon. Electromyography (EMG) studies show that therapist-assisted shoulder elevation, pendulums, and supine PROM generate minimal supraspinatus activation and are safe in the early phase [55]. ER is limited to 30°–60°, and internal rotation is typically avoided to minimize anterior tension.
Phase 2: Mobility and Early Activation (Weeks 7–12)
As tendon-to-bone healing progresses, gradual active-assisted range of motion and active range of motion (AROM) are introduced. Exercises such as wand-assisted flexion, towel slides, and gentle scapular stabilization are effective for promoting shoulder mobility without compromising repair integrity. Delayed initiation of AROM (beyond 6–8 weeks) is recommended for patients with large or massive tears to minimize retear risk. Isometric exercises, including external and internal rotation with a towel roll under the elbow, are initiated to engage the rotator cuff with minimal stress [56].
Phase 3: Strengthening and Functional Restoration (Weeks >12)
Strengthening exercises begin once full, pain-free ROM is achieved without compensatory shoulder shrugging. A progressive strengthening program targets the rotator cuff and scapular stabilizers while maintaining centralization of the humeral head. Exercises such as side-lying ER, prone horizontal abduction, and prone extension effectively activate the posterior cuff and lower trapezius without excessive strain. Electromyography studies suggest that exercises such as ER at 0° abduction with a towel roll, prone ER at 90° abduction, and diagonal movements effectively recruit the rotator cuff and improve stability [57]. For athletes and individuals requiring overhead function, advanced exercises such as prone ER and strengthening in the cocking position (90° abduction) are introduced toward the final stages of this phase.
Scapular dyskinesis, characterized by altered scapular position and movement, is common after rotator cuff injury and repair [58]. A strong emphasis on scapular stabilization exercises throughout rehabilitation is crucial to maintain glenohumeral stability. Exercises such as wall slides, prone horizontal abduction, and the serratus punch have demonstrated high activation of the serratus anterior and lower trapezius, which promotes optimal scapular mechanics. Addressing overactivation of the upper trapezius and underactivation of the middle and lower trapezius prevents impingement and restores proper scapular kinematics.
The most common postoperative complication is retear, with rates ranging from 13% to 94%, depending on tear size, tissue quality, and rehabilitation timing [34]. Immediate mobilization, once thought to prevent stiffness, might compromise tendon healing. Animal studies have shown that a 2-week period of immobilization results in better tendon–bone healing due to improved collagen alignment and reduced scar formation [59]. Patients with large or massive tears might benefit from delayed active motion to minimize strain.
CONCLUSIONS
Arthroscopic rotator cuff repair has advanced significantly, driven by innovations in surgical techniques, biomaterials, and biomechanics. Strategies to address specific challenges, such as retears, partial-thickness tears, and massive tears, have developed significantly. Although current techniques demonstrate promising results, further research into long-term outcomes, patient-specific approaches, and emerging technologies is crucial to refine treatment strategies, optimize functional recovery, and enhance patient satisfaction.
Notes
Author contributions
Conceptualization: KSL, DHK, SWC, JPY. Supervision: SWC, JPY. Validation: DHK, SWC. Writing – original draft: KSL, DHK, SWC, JPY. Writing – review & editing: KSL, SWC, JPY. All authors read and agreed to the published version of the manuscript.
Conflict of interest
Jong Pil Yoon is an editorial board member of the journal but was not involved in the peer reviewer selection, evaluation, or decision process of this article. No other potential conflicts of interest relevant to this article were reported.
Funding
This work was supported by a National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (NRF-2022R1A2C1005374). This research was supported by a grant from the Korean Health Technology R&D Project through the Korean Health Industry Development Institute (KHIDI), fundedistry of Health & Welfare, Republic of Korea (grant no. HR22C1832).
Data availability
None.
Acknowledgments
None.