暨大九型九剑九选治疗体系介绍（二） | 郑小飞教授：无结锚钉改良缝合修复与改良缝合缝线增强修复二种方式对比的一项生物力学研究

Introduction

Lateral ankle sprains represent one of the most  common sports injuries^[1,2]. Approximately 75%   of these sprains result in lateral ligament damage, involving either a partial or complete tear of    t-he anterior talofibular ligament (ATFL) ^[3]. Most  patients can achieve satisfactory outcomes with conservative treatment and functional rehabilitation after injury ^[4]. However,if 3–6 months of cons-ervative management fail to resolve symptomatic ankle instability and repeated ankle sprains, surg-ery should be considered ^[5].

In 1966, Broström described his anatomic           repair of the lateral ankle  ligaments,  particularl-y  the ATFL^[6–8].  Currently,  the Broström techniq-ue and its modifications have been widely regar-ded as the gold standard and preferred surgical  treatment for ATFL injuries. However, reports of  persistent instability have increased, with up to   25% of patients unable to return to sports ^[9]. Ad-ditionally, the efficacy of these repairs has been  questioned in patients with longstanding lateral  ankle instability and weakened native tissue, as well as in overweight patients or athletes who    may place additional stress on their ankles ^[10,11]. Anatomical graft augmentations have been     suggested^[12,13] as an alternative, but these procedures are complex, and a recent systematic      review reported a return to sports rate of only 80% ^[14].

Over the past decade, anchor systems have bee-n developed and implemented, such as securing transplants or providing knotless fixation for sutur-es ^{[15, 16]}. In particular, the technique of the sutur-e anchor repair (SAR) has played a crucial role  in arthroscopic Broström techniques ^[17].            Cottom et al. ^[18] repaired a complete ATFL injury using a single-row, two-suture anchor construct   in an open procedure, with the failure load and  stiffness measured at 156.43 ± 30.39 N and 12.10 ± 5.43 N/mm, respectively. Prosthetic augment-ation techniques using suture tape augmentation (STA), also known as “internal bracing,” have 

gained increasing interest in recent years. A multi-center, prospective, randomized trial by Kulwin 

et al. ^[19] indicated that STA with arthroscopic ass-istance could facilitate a quicker return to a preoperative level of activity compared to modified Broström technique alone, with- out resulting in increased complications or morbidity. Suture tape techniques are particularly recommended for patients with generalized ligamentous laxity, athletes, or those with poor rem- nant tissue quality, such as individuals who have undergone un- successful prior repair or reconstruction ^[20–22]. However, Vega et al. ^[23] reported that an arthroscopic all-inside ATFL repair, incorporating STA combination with suture anchors, could yield outstanding outcomes, particularly in patients exhibiting poor residual ligamentous tissue quality. Therefore, when faced with poor residual quality, the treatment of surgical options for repair or STA for the reconstruction remains controversial.

Although there have been studies on SAR and STA individually in terms of mechanics and clinical research, there is a lack of biomechanical comparisons between the SAR, STA and intact ATFL ^{[18,21,23,24]}. At the same time, anatomical and biome- chanical studies are one of the gold standards for evaluating a surgical  technique.  Besides, 

 limited  research  has  examined the use of biomechanics to evaluate and compare the efficacy

 of SAR and STA for ATFL reconstruction compared to intact ATFL. Therefore, the purpose of this study was to: (i) compare the ultimate failure lo-ad of SAR, STA, and intact ATFL; and (ii) compare 

the stiffness of SAR, STA, and intact ATFL.

2.1   |  Specimens

In this study, a total of 18 fresh-frozen (9 pairs) ankle speci- mens were included, with 9 specimens from the right ankle and 9 specimens from the l-eft ankle. The specimens were obtained from individuals who underwent below-the-knee amputa-tion. The study population consisted of 10 males and 8 females, with a mean age of 62 years (ran-ging from 55 to 73years). These ankle specimen-s were utilized for the research. This study was c-onducted in compliance with the principles of th-e Declaration of Helsinki. The study was approve-d by the Institutional Review Board (IRB) of the First Affiliated Hospital of Jinan University with IRB number KY-2023-220. The  specimens used in  this study were provided by the Department of A-natomy, Faculty of Medicine, Jinan University.

Specimens with a prior history of torn ligaments, ankle surgery, or cancer as the cause of death were excluded. To achieve a sta- tistically signific-ant result, a minimum of 6 ankle specimens is re-quired in each group, based on a priori power analysis. The anal- ysis assumes a significant difference of more than 30%, a standard error of 15%, a power of 0.8, and a significance level of 0.05. Ankles were divided into one of three groups: (1) intact ATFL group, (2) arthroscopically  rec-onstructed with  suture  tape  augmentation inter-nal brace of the ATFL (STA group), and (3) arthroscopically repaired ATFL with suture anchors (SAR group). The ankle spec- imens were preserved intact to maintain ATFL integrity. The an- terior dr-awer test and talar tilt test were performed to co-nfirm the ligaments' intactness. Throughout the e-xperiment, tissues were moistened with saline solution to prevent tissue necrosis.

2.2  |  Surgical Approach

Before the modeling process, individual ankle sp-ecimens un- derwent separate B-ultrasound examinations. The width of the ATFL in each ankle specimen was measured and recorded. The selected specimens were further assessed to ensure consistency with the included specimens. To simulate ATFL injury, a signif- icant portion of the ATFL was surgically excised under ankle ar- throscopy, resulting in a residual superior ligamentous fascicle that was less than 50% of its original.

The standard anteromedial and anterolateral port-als were cre- ated for ankle surgery procedures. An accessory anterolateral portal was established at a distance of 1–1.5cm proximal to the tip of the fibula, situated just anterior to it.  After removing synovial tissue with a planer, the senior surgeon identified the anterior tibiofibular ligament (AITFL) and ensured its visibility throughout the operation. Subsequently, the surgeon located the superior band of the AITFL and its fibular attachment. Under arthrosc-opic guidance, the superior fascicle of the ATFL was then dissected from the fibular footprint using a scalpel. Finally, an anterior drawer test was performed on the specimen.

2.3  |  Suture Anchor Repair

A cannula was inserted through the anterolateral portal to visualize the joint cavity, and the latera-l groove was observed by opening the lateral join-t capsule. A thin guide needle preceded  the  ins-ertion  of a  non-absorbable  suture  (Fiberwire, Arthrex, Naples, USA) through the lumbar puncture needle. The lumbar puncture nee-dle was t-hen inserted from the ex- terior through the inferior band of the ATFL to the interior of the ATFL. The No. 0 suture was subsequently grasped with an arthroscopic grasper via the accessory portal, where the folded suture terminated in a ferrule. Utilizing a s-uture gripper, the suture was extracted through the ferrule and tightened around the band. The ligament was repaired by insertin-g a knotless anchor  (Pushlock  2.9mm×15mm,  Arthrex,  Naples,  USA) through a suture guid-e. For anchorage, the center of the ATFL attachments was drilled at an insertion angle of 30° relative to the fibula's longitudinal axis. The anchor was t-hen threaded through the suture. After deployment, the anchor's ends were sutured  without  severing.  The  drill  sleeve  was  introduced through the anterolateral portal and p-ositioned at the talar neck's center to prevent intrusion into the subtalar joint space. Following the creation of a hole, the sutured bone anchor was inserted into the cavity through the portal. To prevent exces- sive tightness, the ankle should be in a neutral position when the talar anchor was implanted under dorsiflexion. Finally, the suture ends were cut (Figure 1).

FIGURE 1  |  Main steps of the technique of suture anchor repair. (A, F) A high-tensile-strength suture is passed through the puncture introducer into the joint cavity, from the inferior fascicle of ATFL into the medial side. (B, G) After withdrawing the joint, a high-tensile-strength suture loop is visible on the inside of the ATFL. (C, H) A knotless anchor nail was placed into the footprint area of the ATFL fibula. (D, I) After adjusting the tension, another knotless anchor nail was placed in the footprint area of the ATFL talus. (E, J) Postoperative effect.

2.4 | Suture Tape Augmentation Internal Brace of the ATFL

In six ankle specimens, the ATFL attachment was identified but not sutured. Two 3.4 mm holes were drilled in the ATFL foot- print of the fibula and talus using a calibrated drill guide. The talus was then sutured with a 4.75 mm suture anchor and a 2 mm wide suture strip made of ultra-high molecular weight polyeth- ylene  (UHMWPE)  and  polyester  fibers  (FiberTape,  Arthrex Inc.). Suture tape was woven together with the same UHMWPE and polyester fibers. The STA was inserted with appropriate ten- sion during the surgical procedure to support the repaired col- lateral ligament, and the stent was designed with a 1–2 mm gap to allow for normal physiological movement. Finally, using the opposite end of the suture tape, a second 4.75 mm suture anchor was inserted into the fibula under tension.

2.5  |  Separation of ATFL

The soft tissues of the tibia and fibula were completely removed, leaving the skin of the foot intact except for the ATFL attach- ment. The medial deltoid ligament, anterior capsule, and pos- terior  capsule were  removed,  leaving  only  the  intact  lateral ligaments. The calcaneofibular ligament and the posterior talo- fibular ligament were then excised. Finally, the tibia was re- moved, leaving only the fibula and ATFL intact (Figure 2).

FIGURE 2  | Separation of ATFL. (A) Ankle specimen of the intact ATFL after separation. (B) Ankle specimen of tape augmentation internal brace of the ATFL after separation. (C) Ankle specimen of suture anchor repair of the ATFL after separation. sf, superior fascicle of ATFL; if, inferior fascicle of ATFL; ff, fibular footprint of ATFL; tf, talus footprint of ATFL.

2.6   |  Biomechanical Test

For biomechanical testing of the structure, the ankle speci- mens were placed in 20° of varus and 10° of plantarflexion on custom-made wooden fixtures rigidly attached to the feet. The ankle specimens, customized platform, and electronic univer- sal testing machine were assembled on the electronic univer- sal testing machine's base, and calibrated to a load accuracy of 0.25%. A tensile load of 15 N was applied progressively for 10 s, followed by  maintaining  the  same  tensile  load for 5 s to eliminate potential creep. The ATFL was then stretched by  vertically  pushing  the  rod  at  20 mm/min  until  failure. Maximum load (N),  stiffness (N/mm),  and failure patterns were recorded. A universal electronic testing machine (model ATES6010, Guangzhou Aojin Industrial Automation Systems Co. Ltd., China) and its software system were employed for biomechanical testing (Figure 3).

FIGURE 3 | Biomechanical  test.  Prior to  testing,  the right  ankle specimen was securely placed on a universal electronic testing machine. The specimen was placed in 20° of varus and 10° of plantarflexion on a custom-made wooden fixture.

2.7  | Statistical Analysis

3.1  | The Failure Load

Table 1 illustrates the disparities in ultimate loads to failure and stiffness between the two techniques compared to the in- tact ATFL. The mean failure load for the STA (311.20 ± 52.56 N) (Table 1) was significantly higher than that of the intact ATFL (157.37 ± 63.87 N; p = 0.0016) (Table 1; Figure 4) and the SAR (165.27 ± 66.81 N; p = 0.0025) (Table 1; Figure 4). There was no significant difference in the mean load to failure between the SAR and the intact ATFL (p = 0.973).

TABLE 1 | Comparison of ultimate failure load and stiffness of three groups of ankle specimens.

3.2  | The Stiffness

The mean stiffness for the STA (30.10 ± 5.10 N/mm) (Table 1) was notably higher than that of the intact ATFL (14.17 ± 6.35 N/ mm; p = 0.0012) (Table 1; Figure 4) and the SAR (15.15 ± 6.89 N/ mm; p = 0.0021). There was no significant difference in mean stiffness between the SAR and the intact ATFL (p = 0.959).

3.3 | The Situation for the Avulsion of the Ligament at the Talus Footprint

The most significant finding of this study is that, compared to SAR and intact ATFL, STA demonstrates better strength and stiffness in ATFL reconstruction, indicating superior structural stability.

In this study,the ATFL reconstructed with STA demonstrated significantly higher failure loads and stiffness compared to the ATFL reconstructed with SAR and the intact ATFL. Research by Viens et al. ^[21] showed that, compared to the intact ATFL, STA increased the average failure load and stiffness by 50%. Studies by Schuh et  al.  ^[25]  also indicated that STA outper- formed SAR in terms of failure angle and failure torque. The aforementioned findings are consistent with the results of this study. Being spared from excessive stress during the early post- operative rehabilitation phase is one of the crucial factors de- termining the effectiveness of the repair ^[26]. Additionally, STA promotes the formation of scar tissue, restores ankle joint sta- bility, and serves a protective role for the ligament during the healing process ^{[27, 28]}.

4.1  | The Failure Load and Stiffness of the Intact ATFL

Compared to the previously determined ultimate failure loads of the intact ATFL by Attarian et al. ^[29], Waldrop et al. ^[26] and Viens et al. ^[21], in our study, the ultimate failure load of the  intact  ATFL  was  consistent  with  those  of  the  previous studies (Ultimate failure load:  138.9 ± 23.5 N  [Attarian et al.], 160.9 ± 72.2 N [Waldrop et al.], 154.0 ± 63.7 N [Viens et al.] vs. 157.37 ± 63.87 N). Additionally, compared to the stiffness of the intact ATFL reported by Clanton et al. ^[30] and Xiao et al. ^[31] as 14.5 ± 4.4 N/mm and 12.1 ± 3.8 N/mm, respectively, the stiff- ness of the intact ATFL in this study was 14.17 ± 6.35 N/mm. In summary, regarding the ultimate failure load and stiffness, our study's findings were consistent with those of the previous studies.

4.2  | The Failure Load and Stiffness of the SAR

In 2018, a study by Guillaume Cordier et al. ^[32] showed a total of 12 cadaveric specimens had two-fascicled and demonstrated that connecting fibers between the inferior fascicle of the ATFL and the calcaneofibular ligament was robust enough to transfer tension from one structure to the other. Therefore, we addressed a novel technique to repair ATFL using two suture anchors. In this technique, the superior and inferior fascicles of the ATFL were sutured into one unit, allowing traction to be transferred from the ATFL to the calcaneofibular ligament, thus reducing the risk of anchor avulsion. Meanwhile, we found that the ul- timate load to failure and stiffness of SAR was 165.27 ± 66.81 N and  15.15 ± 6.89 N/mm,  respectively.  The  SAR  in  our  study showed a comparable strength and stiffness to the intact ATFL. Since our results indicate a strength of SAR similar to the in- tact ligament, it demonstrates that this new SAR of the ATFL allows for early loading. Compared to the failure load and stiff- ness of the ATFL repaired with a single-row, two-suture anchor construct used by Cottom et al. ^[18], the results obtained in this study are similar (Failure load: 156.43 ± 30.39 N [Cottom et al.] vs. 165.27 ± 66.81 N; Stiffness: 12.10 ± 5.43 N/mm [Cottom et al.] vs. 15.15 ± 6.89 N/mm). In conclusion, the SAR technique can achieve reliable stability, and the results of this study are credible.

4.3  | The Failure Load and Stiffness of the STA

Before the current study, there was no information regarding the strength and stiffness of STA and SAR procedures for the ATFL compare to the intact ATFL. Therefore, we designed a biomechanical study to evaluate these procedures. Our results yielded significant biomechanical data on both STA for recon- struction and SAR of the ATFL. The mean ultimate load to failure of STA (311.20 ± 52.56 N) was significantly higher than that of SAR (165.27 ± 66.81 N). Additionally, the mean stiff- ness of STA surpassed that of SAR. The literature provided limited information on the stability of biomechanical exper- iments involving STA. In comparison to the study by Viens et al. ^[21] that used STA for ATFL repair alone, they found the ultimate failure load and stiffness to be 311.20 ± 52.56 N and 30.10 ± 5.10 N/mm, respectively, which are significantly higher  than  those  of the  intact ATFL,  consistent with  our findings. Schuh et al. ^[25] performed a biomechanical study comparing traditional Broström repair, Broström repair with SAR, and STA. The study demonstrated a 95% higher torque at failure in the STA compared to traditional Broström repair, and a 54% higher torque at failure compared to Broström with SAR, which aligned with our study. Additionally, Willegger et al.  ^[33] performed a biomechanical study and found that the utilization of STA for ATFL reconstruction yielded biome- chanical stability similar to that of a native ATFL, as demon- strated by torque and angle at failure. The authors did not find statistically significant differences for these parameters

between STA for ATFL reconstruction and the native ATFL. However, they did not evaluate the biomechanical stability of SAR. At the same time, they did not compare the strength and stiffness of the STA to that of the intact ATFL. These bio- mechanical results may also explain why the earlier weight bearing, cast removal, and return to sport are possible after STA. It is important to note that prolonged immobilization can alter fibrillar collagen remodeling and cellular orientation synthesis,  ultimately  reducing  ligament  strength  ^[34].  This is particularly relevant for athletes, as STA may facilitate an earlier return to activity and a faster return to sports, with a decreased risk of recurrent instability and the necessity for revision surgery. The outcomes of this study can also offer valuable  insights  into ATFL  injuries,  especially  in  specific populations such as overweight individuals and athletes.

4.4  | Strengths and Limitations

The study is the first to assess the biomechanical properties of intact ATFL, STA, and SAR, and therefore simulated the most prevalent  inversion  internal  rotation  mechanism  for  ankle sprains, using torsion to failure in plantar flexion and inver- sion. This provides a certain basis for a better understanding of the ankle sprains mechanism and the surgical technique mechanism.  For  patients  with  poor  residual  conditions  of 

the ATFL, the study proves that the STA technique is a good choice.

There are several limitations to this study. First, the average age of the specimens used was 62 years, which is relatively high and may not accurately represent the age of patients who typically experience lateral ankle sprains leading to chronic instability. Second, the sample size of the human specimens was small. However, a power analysis was performed to ensure that the sample size was sufficient to produce statistically significant results. Finally, the study sought to simulate in vivo conditions within a laboratory setting, which may not fully represent the in vivo loads applied to the ATFL.

Arthroscopic reconstruction of the ATFL using STA proves to be biomechanically more stable than repair using suture anchors and intact ATFL. In particular, the reconstruction of the ATFL with STA provided superior biomechanical advantages compared to the SAR. Additionally, the novel technique of all-inside arthroscopic ATFL repair with two suture anchors is a reliable technique that offers biomechanical properties similar to intact ATFL. Further study is warranted to explore the potential of constructs used for arthroscopic lateral ankle stabilization in clinical settings.