Classical anatomical view of the deltoid ligament
The deltoid ligament, also known as the medial collateral ligament, supports the stability of the ankle joint in conjunction with other structures of the ankle joint. The deltoid ligament is a composite ligament with a fan-shaped structure that consists of a superficial and a deep layer. The superficial layer consists of the tibial navicular ligament, the superficial posterior tibial talofibular ligament, the tibial heel ligament and the tibial spring ligament, of which the tibial spring ligament is the most important part of the superficial layer to maintain joint stability. The deeper layer consists of the anterior deep tibial talofibular ligament and the posterior deep tibial talofibular ligament, of which the posterior deep tibial talofibular ligament is the most solid part of the deep layer and even the entire deltoid ligament complex, with its proximal end starting from the posterior malleolus and interdigital sulcus of the medial ankle and ending distally at the medial aspect of the talus, where the tibial spring ligament is separated from the tibial heel ligament.
MiLner et al. concluded that the distinction between superficial and deep deltoid ligaments is based on the number of joints crossed by the ligament, with deep ligaments crossing only the ankle joint and superficial ligaments crossing both the ankle and subtalar joints.
Modern view of deltoid ligament anatomy
In recent years, some improvements have been made to the classic anatomical view of the deltoid ligament, and Boss et al. found that although the tibial spring ligament and the deep posterior tibial talofibular ligament were relatively constant, there were still some populations in which the tibial navicular ligament, the superficial posterior tibial talofibular ligament, the tibial heel ligament, and the deep anterior tibial talofibular ligament were not evident in the deltoid ligament. volunteers with normal ankle triangular ligaments and showed that the tibial spring ligament and the deep posterior tibial talar ligament were present in all volunteers, but the tibial navicular ligament and the deep anterior tibial talar ligament were present in only 55% of the volunteers, and no significant tibial heel ligament was found in about 12% of the volunteers. It is evident that there are individual differences in the presence of tibial navicular ligament, superficial posterior tibial talar ligament, tibial heel ligament, and deep anterior tibial talar ligament.
Mechanical characteristics of the deltoid ligament
The deltoid ligament is the tissue that connects the distal tibia to the talus and stabilizes the medial ankle, and TocHigi et al. found that the deltoid ligament was tense in neutral, plantarflexed and dorsal extension positions of the ankle. It is now accepted that the deep layer of the deltoid ligament has a much greater stabilizing effect on the ankle joint than the superficial layer, with the superficial layer acting mainly to avoid excessive talar adduction and the deep layer acting mainly to maintain joint stability by limiting excessive anterior rotation of the talus.
It has been shown that when the superficial layer of the deltoid ligament is injured, the talus is often not significantly displaced, while when both the deep and superficial layers of the deltoid ligament are injured, the stability of the inner ankle is extremely poor. In this regard, EarLL et al. conducted mechanical tests on the function of each component of the deltoid ligament and found that there was a different degree of increase in talar tilt and external rotation after cutting the posterior deep tibial talar ligament or the tibial heel ligament, respectively, and the effective joint surface was reduced by 26% to 43% after cutting the posterior deep tibial talar ligament and the tibial heel ligament simultaneously, and the center of gravity was shifted by about 4 MM, while cutting the other parts of the deltoid ligament had less effect on the stability of the ankle joint.
Diagnosis of deltoid ligament injury.
Clinical presentation.
Similar to other sports system injuries, the main clinical manifestations of deltoid ligament injury are swelling, pain and dysfunction, specifically, pressure pain in the anterior part of the affected limb of the inner ankle, local bruising and swelling, and ankle instability.DeAngeLis et al. conducted clinical statistics on 55 patients with ankle type B fractures and found that most patients had medial ankle joint pressure pain during physical examination, and some cases were found to be The deltoid ligament injury was found to be present.
Given the importance of deltoid ligament anatomy and function, deltoid ligament injury should be highly suspected when ankle instability is found on examination, and a heel lift test should be performed to exclude posterior tibial tendon injury.
Imaging examination.
The diagnosis of deltoid ligament injury mainly relies on imaging examinations (ultrasound, X-ray, MRI examination, etc.). The sensitivity and specificity of ultrasound examination for deltoid ligament injury was found to be 100% in 12 cases of ultrasound, X-ray and arthrography in patients with ankle external rotation fractures. He Xiuzhen et al. selected 32 patients with deltoid ligament injury and compared the results of ultrasound examination with MRI examination, and found that only 28 cases had the same results. They concluded that although ultrasound examination is highly feasible, the accuracy of its results is influenced by the operator’s experience and subjectivity.
MRI examination can clearly detect soft tissue edema, ischemia and discontinuity, and therefore has a high value for acute ligament injury. Therefore, it has a high value in the evaluation of acute ligament injuries. The arthroscopic technique, which has emerged in recent years, has the advantage of being more intuitive in the diagnosis of internal ankle injuries, and was reported in detail by HinTerMann et al. In contrast, CT examination is poor for soft tissue display and has less value for application and evaluation.
Triangular ligament injury treatment.
Conservative treatment.
In the 1990s, there was controversy among scholars as to whether ankle injuries required repair of the medial structures (deltoid ligaments). The traditional view was that in patients with a single ankle fracture with localized ankle injury but no significant displacement, a single external cast fixation (immobilization in the neutral ankle position) was recommended within 6 to 8 weeks of injury. However, in recent years, follow-up found that patients with a single external cast fixation were significantly more likely to have complications in the long term than surgical patients. Zhang Cheng et al. concluded that for patients with superficial deltoid ligament injuries, external fixation in a cast for 4-6 weeks (fixation in the ankle inversion position) is possible.
The histological study by ClayTon et al. found that the ligament retracted after complete dissection and the scar tissue gradually filled the gap to achieve the repair effect. In terms of long-term effects, the strength of the deltoid ligament will be weakened after rupture or scar healing, and the external ankle will be under great stress during external rotation and valgus of the talus, which will lead to ankle pain and other manifestations of traumatic arthritis in the long run. RaMMeLT et al. followed up 45 patients with traumatic ankle arthritis treated conservatively and found that ischemic necrosis of the talus occurred in 21 cases. Therefore, conservative treatment is not suitable for patients with complete rupture of the deltoid ligament.
Surgical treatment
Indications for surgery.
For deltoid ligament injury with clear imaging evidence or clinical manifestations of ankle instability (bruising and swelling of the medial aspect of the ankle joint with a hollow feeling below the medial ankle on palpation; MRI examination showing rupture of the deltoid ligament; ankle cavity radiograph showing lateral displacement of the talus or widening of the gap between the medial ankle and the talus by more than 3 MM; external stress radiograph showing lateral displacement of the talus with an angle greater than 15° to the tibial articular surface). Surgery is recommended.
Treatment of acute injury of the deltoid ligament
The treatment of triangular ligament injury in the ankle joint has its own focus, with foreign scholars preferring ligament reconstruction and domestic scholars preferring ruptured ligament repair (using wire anchor nailing technique). Triangular ligament reconstruction: MkandaWire et al. used the peroneus longus tendon instead of the deltoid ligament in their study, i.e., the peroneus longus tendon stop was selected as the surgical entry point, the peroneus longus tendon was exposed and severed there, and the severed peroneus longus tendon was passed through the talar bone tunnel to the medial ankle, then through another bone tunnel of the medial ankle to the lateral tibia, and the tendon was fixed on the lateral tibia.
The more commonly used methods for reconstruction of the deltoid ligament include the WiLTBerger method, the DeLand method, the KiTaoka method, and the HinTerMann method, but none of these methods can achieve complete restoration of ankle external rotation and valgus stability at the same time, with the KiTaoka method mainly serving to restore ankle external rotation stability and the DeLand method completely restoring ankle valgus stability. Roukis et al. modified the classic Evans procedure by placing the short fibular tendon laterally through the medial talar bone tunnel and fixing it at the midline of the distal talus plantaris, which could better restore joint stability after ankle arthroplasty.Wu et al. followed up patients with severe medial ankle injuries, even with bone defects, for an average of 3.5 years and found that the lateral femoral and latissimus dorsi muscles were selected as free flaps The long-term results were satisfactory when combined with vascularized fibular head graft to reconstruct the defective medial ankle structure.
Wire anchor technique: For acute injury of deltoid ligament, direct suturing and wire reconstruction were often used for treatment in the past. With the development of medical technology, the technique of anchor nailing with wires came into being. Chen Nong et al. retrospectively analyzed 21 cases of deltoid ligament repair using wire anchor nailing technique, in which the nail entry point was located at the talar stop of the deep deltoid ligament, and the deep deltoid ligament was repaired and reconstructed at the same time, and the superficial layer was sutured directly. The Baird-Jackson score was 85%.
The follow-up study found that the wire anchor nailing technique had a higher rate of excellent treatment for deltoid ligament injuries than the conventional procedure and was more effective in repairing deep posterior tibial distance ligament injuries. The anchor body of the wire anchor can be completely buried in the bone tissue, which does not cause great stimulation to the surrounding soft tissues after surgery and does not require secondary surgical removal; the operation is simple and can avoid secondary damage to local tissues caused by external incision; the material of the anchor body is reliable and can firmly grip the bone cortex, so that the healing process of the ligament is not disturbed; the 4-strand tension wire attached to the caudal end of the anchor can not only repair the ruptured ligament, but also play a certain degree of early The four strands of tension wire connecting the caudal end of the anchor can not only repair the ruptured ligament, but also play a role in early reconstruction of the deep layer of the deltoid ligament to some extent.
In other words, even if there is a delay in healing due to insufficient blood supply to the ruptured ligament, at least two strands of tension lines can play a mechanical role in replacing the deep layer of the deltoid ligament. The author recommends performing the operation of anchor nailing repair with wires in the ankle valgus state to obtain a good view. The tension wire at the tail of the anchor needs to be fixed and knotted in the ankle inversion state. The anchor nail should be buried at least 2 MM into the bone cortex to avoid postoperative pain. When the anterior malleolar bone block in the inner ankle is found to be too small (less than 1.7CM) intraoperatively, the deep deltoid ligament should be promptly explored and repaired. When the deep and superficial layers of the deltoid ligament need to be separated during surgery, it is recommended to start from the distal end.
Immobilization of the affected limb
Immediate postoperative functional exercise is not recommended for patients with deltoid ligament injury to avoid delayed healing or secondary injury. It is generally recommended to apply immobilization shoes for 6 weeks after repair of the proximal deltoid ligament injury, while external fixation with a tubular cast for 6 weeks is recommended when the distal tibial spring ligament is involved.
Treatment of old deltoid ligament injuries
For patients with old deltoid ligament injuries, preoperative ankle arthroscopy can be performed and the deltoid ligament should be repaired immediately if the injury is clearly present. BoHay et al. reported the reconstruction of the deltoid ligament using an autologous bunion flexor tendon, and ELLis et al. used an autologous fibularis longus transfer to treat adult patients with severe acquired flatfoot. The tibial navicular ligament was replaced by the metatarsal tendon between the medial ankle and navicular bone in the treatment of severe flatfoot.
Conclusion
The anatomical location of the deltoid ligament in the ankle joint is hidden, and if the injury is not treated promptly, it may lead to long-term complications such as traumatic arthritis. If a clear imaging basis or clinical manifestation of ankle instability occurs during the treatment, surgery is recommended.
Currently, for the treatment of deltoid ligament injury, foreign scholars tend to perform tendon grafting to reconstruct the deltoid ligament, while domestic scholars prefer ruptured ligament repair. Considering the factors of safety, convenience and reliability, the wire anchor technique is still one of the better choices in the repair of deltoid ligament.