Biomechanical studies of the lateral collateral ligaments of the ankle using amputated limbs

In order to study the biomechanical behavior of the lateral ligaments around the ankle joint, strains on the anterior talofibular and the calcaneofibular ligaments were measured under adduction and supination loads. The amount of anterior shift of the talus was also examined under anterior "drawer" force. Specially designed omega-shaped transducers and jig sets to hold a leg and to give various loads to the foot were used for the experiments. Twenty human cadaver specimens of various ages were subjected for the study. The results showed the importance of not only the anterior talofibular ligament but also the calcaneofibular ligament as the stabilizer of the ankle joint and that the calcaneofibular ligament plays an important role in adduction, and the anterior talofibular ligament in both adduction and supination. Transection studies of the ligaments revealed that the calcaneofibular ligament is responsible to some extent for producing positive anterior drawer sign for which, as hitherto considered, the anterior talofibular ligament is the main factor.     

An analysis of the function of the posterior talofibular ligament

The function of the posterior talofibular ligament was studied using an apparatus which subjected the ankle joint to a measured torque and allowed the simultaneous recording of rotatory movements in two planes. Thirty osteoligamentous preparations of ankle joints were examined, half in the sagittal and horizontal planes and the remainder in the sagittal and frontal planes. Successive section of the lateral collateral ligaments was performed, including, in particular, selective division of the short and long fibres of the posterior talofibular ligament. The function of this ligament was investigated in combination with the other two collateral lateral ligaments, with the calcaneofibular ligament alone, and finally as the only remaining intact ligament. The posterior talofibular ligament plays only a supplementary role in ankle stability when the lateral ligament complex is intact. After rupture of the anterior talofibular and the calcaneofibular ligaments, however, the short fibres of the posterior ligament restrict internal and external rotation, talar tilt, and dorsiflexion, while its long fibres inhibit only external rotation, talar tilt, and dorsiflexion. As the posterior talofibular ligament has no independent stabilizing function in the intact ankle joint, an isolated rupture of this ligament is unlikely.     

Watson-Jones tenodesis for ankle instability. A mechanical analysis in amputation specimens

The stabilizing effect of a modified Watson-Jones ankle tenodesis was studied in 10 lower extremity amputation specimens using a kinesiologic testing device. Cutting of the lateral ligaments caused maximal instability in adduction of the entire hindfoot joint complex, as well as of the talocalcaneal joint. The tenodesis restricted adduction and internal rotation when compared with the movement pattern with intact ligaments. Instability in external rotation persisted because the tenodesis did not restore the function of the calcaneofibular ligament. Our study confirms clinical observations that the Watson-Jones ankle tenodesis prevents abnormal inversion of the hindfoot, but does not restore hindfoot kinematics.     

A Rare Pattern of Ligamentous Injury of the Ankle: A Case Report and Review of the Literature

Ankle sprains are the most frequent sport related injuries with involvement of the lateral collateral ligament complex occurring in 85% of cases. Isolated anterior talofibular ligament injury is by far the commonest followed by combined anterior talofibular and calcaneofibular ligament strain. The posterior talofibular ligament is the strongest component of the lateral collateral ligament complex and is injured in severe ankle injury along with the other lateral collateral ligaments. While isolated calcaneofibular ligament strain has been reported, calcaneofibular ligament and posterior talofibular ligament strains with an intact anterior talofibular ligament are rare and reported in cadaveric studies. We present a case of radiologically diagnosed calcaneofibular ligament and posterior talofibular ligament injury and will discuss the anatomy, stress radiography, and magnetic resonance image findings and the mechanism of this particular injury.     

Proximity of the lateral talar process to the lateral stabilizing ligaments of the ankle and subtalar joint

BACKGROUND: Fractures of the lateral process of the talus have become more frequent as the sport of snowboarding has gained popularity. The anatomy of the ligamentous attachments to the process has been described, but ligament proximity to the lateral talar process has never been specified. The objective of this cadaver study was to measure the proximity of the lateral talar process to the various lateral stabilizing ligaments of the ankle and subtalar joint: the anterior talofibular ligament, lateral talocalcaneal ligament, posterior talofibular ligament, interosseous ligament, cervical ligament, and lateral root of the extensor retinaculum. METHODS: After thawing, all musculotendinous structures from 10 fresh-frozen cadaver lower limbs were carefully removed and the distal fibula was reflected to enable adequate exposure of the lateral talar process and ligamentous attachments. The apex of the lateral process was defined. Subsequently, the distance from the apex to the nearest edge and center of these surrounding ligaments was independently measured by two examiners. RESULTS: The average apex-edge distances were 9.3 mm (posterior talofibular); 8.7 mm (anterior talofibular), 3.4 mm (lateral talocalcaneal), 13.9 mm (interosseous), 19.1 mm (cervical), and 13.0 mm (lateral root of extensor retinaculum). The average apex-center distances for those ligaments found to actually insert on the lateral talar process were 18.0 mm (posterior talofibular), 15.7 mm (anterior talofibular), and 6.2 mm (lateral talocalcaneal). CONCLUSIONS: Contrary to previous reports, our cadaver dissections identified that only three ligaments attach to the lateral process of the talus: lateral talocalcaneal, anterior talofibular, and posterior talofibular. CLINICAL RELEVANCE: Familiarity with these anatomic relationships may help guide the clinical treatment of lateral talar process fractures.     

Mechanical response of ankle ligaments at low loads

BACKGROUND: The aim of this study was to examine the mechanical behavior of human ankle ligaments at low forces. Predominantly, ankle ligaments have been studied under the auspices of ligament injury. While the mechanical properties of a ligament when tested to failure provide a basis for comparisons, the loads and displacement do not reflect normal physiologic loading. METHODS: Eight fresh-frozen ankles (mean age 65) were dissected to expose the ligaments surrounding the talocrural joint. Eight ankle ligaments were studied and included: medially-anterior tibiotalar (ATTL), posterior tibiotalar (PTTL), tibiocalcaneal (TCL); laterally-anterior tibiofibular (ATiFL), posterior tibiofibular (PTiFL), anterior talofibular (ATFL), posterior talofibular (PTFL), and calcaneofibular (CFL). Stress relaxation tests were carried out at 30% and 10% strain. The peak load and area under the curve were assessed for all experiments. RESULTS: Significant differences were found for the average peak loads of the elastic response between 30% and 10% strain for each ligament (p < .05). At 10% strain the relationship between the ligaments on the medial and lateral side revealed a Pearson R value of .991 (p = .087). No significant difference was found between the strain energies of the various ligaments (p > .05). The anterior talofibular ligament was found to possess similar relaxation results to the medial ligaments. The calcaneofibular ligament relaxed up to 10% more compared to the anterior talofibular for the same relaxation period. The mechanical testing was performed in uniaxial tension and did not consider off-axis loading that may occur in vivo during ankle motion. CONCLUSIONS: The stress relaxation experiments revealed all ligaments to relax even when loaded to less than 5 N, reflecting the viscoelastic nature of ligaments. The stress relaxation results show that the anterior talofibular ligament does not relax to the same extent as the other lateral ligaments. Examining the properties of human ankle ligaments at low loads has revealed some new findings. CLINICAL RELEVANCE: This study highlights the need to understand the synergistic effects of the ligaments. This is important for reconstruction and arthroplasty procedures.     

Comparison Between the Simultaneous Reconstructions of the Anterior Talofibular Ligament and Calcaneofibular Ligament and the Single Reconstruction of the Anterior Talofibular Ligament for the Treatment of Chronic Lateral Ankle Instability

This study aimed to evaluate the procedures of reconstruction surgery for chronic lateral ankle instability. We compared single anterior talofibular ligament reconstruction to simultaneous reconstructions of the anterior talofibular and calcaneofibular ligaments. From 2015 to 2019, 14 consecutive patients diagnosed with chronic lateral ankle instability underwent arthroscopic anterior talofibular ligament reconstruction with or without calcaneofibular ligament reconstruction after conservative treatment. Seven patients underwent single anterior talofibular ligament reconstruction (group AT), and 7 patients underwent simultaneous reconstructions of the anterior talofibular ligament and calcaneofibular ligament (group AC). The Japanese Society for Surgery of the Foot scale scores and Karlsson scores significantly improved in all patients 1 year postoperatively. The radiographic measurement of the talar tilt angle and the talar anterior drawer distance at 1 year after surgery were also significantly improved compared to preoperative values. The postoperative talar tilt angle was significantly greater in group AT (median 6°, range 3°-7°) than that in group AC (median 3°, range 2°-5°; p = .038). The postoperative talar anterior drawer distance, Japanese Society for Surgery of the Foot scale score, and Karlsson score were not significantly different between the 2 groups.We found that although the clinical outcomes after the anterior talofibular ligament reconstruction with or without the calcaneofibular ligament reconstruction for chronic lateral ankle instability were good, instability of the talar tilt angle at 1 year postoperatively in patients who underwent single anterior talofibular ligament reconstruction was greater than that in patients who underwent simultaneous anterior talofibular and calcaneofibular ligament reconstructions.     

Instability of the subtalar joint

Instability of the subtalar joint can follow inversion stress injuries to the lateral ankle and hindfoot. Ligaments involved in the injury include the calcaneofibular, lateral talocalcaneal, cervical, interosseous talocalcaneal, or a combination. Although the problem most often occurs in conjunction with lateral ankle instability, it may be an isolated problem and it is not corrected equally well by the various lateral ankle ligament reconstructions. Techniques available for diagnosis include routine stress radiographs of the ankle, which also include the subtalar joint, specific subtalar stress radiographs, stress tomograms, fluoroscopy, or subtalar arthrograms. Once diagnosed, subtalar instability symptoms can be treated by either nonoperative or operative means.     

Detecting Ankle Instability With an Instrumented Ankle Arthrometer: An Experimental Study

A new instrumented device was developed to quantify ankle joint stability during an anterior talar drawer test. The aim of the present study was to validate this device comparing bone kinematics with arthrometer measurement outcomes. An anterior talar drawer test was performed with 14 cadaver legs using a custom instrumented ankle arthrometer. Using clusters of bone‐pin markers, the relative three‐dimensional movement of calcaneus, talus, and fibula was simultaneously measured. Anterior drawer test was applied on the intact foot and after sequentially sectioning the anterior talofibular ligament, the calcaneofibular ligament, and the posterior talofibular ligament. Cutting the anterior talofibular ligament caused a significant increase in bone‐pin measured anterior translations of calcaneus and talus as well as in the anterior translation of the arthrometer. Analysis of receiver operating characteristic curves indicates a fair to good ability to discriminate between the intact and the sectioned conditions with the arthrometer. Distal distraction, inversion, and internal rotation movements were observed when two and three ligaments were cut. Results revealed that the ankle arthrometer was sensitive to detect changes in bone‐to‐bone movements during an anterior talar drawer test, when the anterior talofibular ligament was sectioned. Presumably due to movements in additional planes of motion, the arthrometer was not able to differentiate between situations with one or more ligaments cut. In conclusion, the instrumented anterior talar drawer tester may augment current procedures in assessing ankle instability primarily caused by ruptures of the anterior talofibular ligament. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2019–2026, 2019     

Acute and chronic lateral ankle instability in the athlete

Ankle sprain injuries are the most common injury sustained during sporting activities. Three-quarters of ankle injuries involve the lateral ligamentous complex, comprised of the anterior talofibular ligament (ATFL), the calcaneofibular ligament (CFL), and the posterior talofibular ligament (PTFL). The most common mechanism of injury in lateral ankle sprains occurs with forced plantar flexion and inversion of the ankle as the body's center of gravity rolls over the ankle. The ATFL followed by the CFL are the most commonly injured ligaments. Eighty percent of acute ankle sprains make a full recovery with conservative management, while 20% of acute ankle sprains develop mechanical or functional instability, resulting in chronic ankle instability. Treatment of acute ankle sprains generally can be successfully managed with a short period of immobilization that is followed by functional rehabilitation. Patients with chronic ankle instability who fail functional rehabilitation are best treated with a Brostrom-Gould anatomic repair or, in those patients with poor tissue quality or undergoing revision surgery, an anatomic reconstruction.     

Experimental Ankle Injuries: Analysis of the Traumatology of the Ankle Ligaments

On 32 osteoligamentous ankle preparations forced movements were performed in varying, accurately defined directions. the sequence in which this caused rupture of the individual ligamentous structures of the ankle is described. Dorsiflexion traumas predominantly injured the posterior part of the deltoid ligament, while in plantar flexion traumas the injuries primarily involved the anterior capsule and the anterior talofibular ligament. Internal rotation traumas injured the anterior talofibular ligament and the short, anterior fibres of the posterior talofibular ligament before the calcaneofibular ligament was damaged, whereas in adduction traumas the calcaneofibular ligament ruptured first. Forced external rotation primarily caused rupture of the deep structures of the deltoid ligament, while conversely abduction traumas first caused rupture of the superficial part of this ligament.     

自体半腱肌腱重建距腓前韧带和跟腓韧带治疗踝关节外侧不稳

目的探讨自体半腱肌腱重建距腓前韧带和跟腓韧带治疗踝关节外侧不稳的临床效果及安全性。方法对16例踝关节外侧不稳患者行自体半腱肌腱重建距腓前韧带和跟腓韧带手术,观察踝关节功能情况。结果患者均获得随访,时间1~3年。术后6、12个月摄踝关节内翻应力位X线片未见距骨倾斜,均未发生复发踝关节外侧不稳。术后AOFAS评分为83.52分±7.26分,明显高于术前的50.45分±4.58分。踝关节功能评定:优8例,良7例,可1例。结论自体半腱肌腱重建距腓前韧带和跟腓韧带治疗踝关节外侧不稳疗效确切,安全性高,是一种较为理想的术式。     

Effects of lateral ligament sectioning on the stability of the ankle and subtalar joint

Patients with subtalar joint instability are often diagnosed with ankle instability. Only after a prolonged period of time in which a patient does not improve after treatment for ankle instability is subtalar joint instability considered. To develop a clinically relevant method to diagnose subtalar joint instability, the kinematics of the simulated unstable subtalar joint were examined. A 6 degree‐of‐freedom positioning and loading device was developed. Plantarflexion/dorsiflexion, inversion/eversion, and internal/external rotation were applied individually or as coupled motions along with an anterior/posterior drawer. Kinematic data were collected from sensors attached to the calcaneus, talus, and tibia by keeping all the ligaments intact, and by serially sectioning anterior talofibular ligament (ATFL), calcaneofibular ligament (CFL), cervical ligament, and talocalceneal interosseous ligament. Kinematic results were reported using Euler angles. The ATFL and CFL contributed talocrural instability, similar to previous studies. The interosseous ligament was the greatest contributor to subtalar joint stability. The hindfoot motion (calcaneus relative to tibia) showed significant increases in motion when the ankle and/or subtalar joint was made to be unstable. Therefore, it is difficult to diagnose subtalar joint instability on physical examination alone. © 2011 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29: 1459–1464, 2011     

Changes in the flexibility characteristics of the ankle complex due to damage to the lateral collateral ligaments: An in vitro and in vivo study

This study was part of a long-term effort to develop a reliable diagnostic procedure for ankle ligament injuries. Earlier efforts led to the development and validation of a six-degrees-of-freedom instrumented linkage capable of measuring the flexibility characteristics of the ankle complex in vitro and in vivo. The major goal of the present study was to determine if these flexibility measurements are sufficiently sensitive to detect the presence of damage to the lateral collateral ligaments of the ankle joint both in vitro and in vivo. The in vitro testing was conducted on the legs from six fresh cadavers before and after serial sectioning of the anterior talofibular ligament and the calcaneofibular ligament. The flexibility in inversion-eversion, anterior drawer, and internal-external rotation was measured before and after resection of the ligaments. The in vivo testing was conducted on five patients with unilateral injuries to the ankle ligament. The flexibility evaluation used for in vitro specimens was also performed on both the injured and the intact ankles. For the in vitro testing, the data analysis was based on comparison of flexibility values before and after resection of the ligaments, whereas the data analysis for the in vivo testing was based on comparison of the flexibility of the injured joint with that of the intact contralateral joint. The results of the in vitro study indicated that both an isolated rupture of the anterior talofibular ligament and combined damage of the anterior talofibular and calcaneofibular ligaments produce statistically significant changes in flexibility. Furthermore, the most sensitive parameters to the presence of ligament injuries were found to be early flexibility in anterior drawer, early flexibility in inversion, and the amount of coupling between internal rotation and inversion. These parameters provided a basis for differentiating between an isolated injury to the anterior talofibular ligament and a combined anterior talofibular and calcaneofibular ligament injury. For an isolated anterior talofibular ligament injury, a significant increase in flexibility in anterior drawer was present, whereas the increase in inversion flexibility or in the amount of coupling was insignificant. However, the increases in inversion flexibility and the amount of coupling became significant when both ligaments were involved. The results of the in vivo study indicated that significant changes in flexibility can be detected in patients with lateral ankle injuries. Finally, both the in vitro and in vivo results suggest that development of a reliable diagnostic test for ankle ligament injury based on changes in passive flexibility may be possible.     

The stress-tenogram in the diagnosis of ruptures of the lateral ligament of the ankle.

The stress-tenogram is a radiological technique for the investigation of injuries to the lateral ligament of the ankle, and combines the information previously provided by inversion and anterior stress radiographs, and the peroneal tenogram. It is designed to differentiate between stable and unstable ankles, and between isolated ruptures of the anterior talofibular ligament and combined tears of the anterior talofibular and calcaneofibular ligaments. A high degree of diagnostic accuracy has been confirmed at operative repair in a group of thirty-two patients.     

Histomorphometric evaluation of mechanoreceptors and free nerve endings in human lateral ankle ligaments

INTRODUCTION: Joint mechanoreceptors have been studied and most of investigators recognize the potential role of mechanoreceptors in the proprioceptive function of joint. The aim of this study was to analyze the general innervation and the possible existence of sensory receptors in the lateral ankle ligament. METHODS: Lateral ankle ligaments including anterior talofibular, posterior talofibular and calcaneofibular were obtained from 24 ankles of 13 male cadavers with ages ranging from 18 to 65 (mean 41.6) years. Each ligament was divided into three parts according to the bony attachments (proximal, central, and distal segments). Histologically mechanoreceptors (Ruffini, Pacini and Golgi) and free nerve endings were identified, and classified. Histomorphometric determination and evaluation of the density of the area of the receptor was performed by the point-counting methods. RESULTS: The anterior talofibular, posterior talofibular, and calcaneofibular ligaments were endowed with mechanoreceptor and free nerve endings. There was a significant prevalence of Pacini (p<0.001) compared with Ruffini and Golgi. However, there was no significant difference in the mechanoreceptors density in the different ligaments analyzed (p>0.05) CONCLUSION: Innervation of the lateral ankle ligaments was confirmed in this study, suggesting that the presence of mechanoreceptors could have clinical implication as well as relevance in the proprioceptive function. Future electrophysiological studies will be required to define the role in the proprioceptive and nociceptive system of the ankle.     

Influence of the interosseous talocalcaneal ligament injury on stability of the ankle-subtalar joint complex--a cadaveric experimental study

The present study aims to clarify the influence of the interosseous talocalcaneal ligament (ITCL) injury associated with injury to the lateral ankle ligaments on the ankle-subtalar joint complex motion under conditions of physiologic loading. We conducted mechanical tests using five fresh cadaveric lower extremities. Each specimen was mounted in the loading device and an axial cyclic load from 9.8 to 686 N was applied. Three-dimensional rotations of the ankle and the subtalar joint were measured simultaneously by a linkage electric goniometer. Mechanical tests were repeated after sectioning of the anterior talofibular ligament (ATFL), and again after additional sectioning of the ITCL. In the intact condition, the ankle and the subtalar joints rotated consistently with increase of the load. The predominant rotations were plantar flexion and adduction at the ankle joint, with some eversion demonstrated at the subtalar joint. Although ATFL sectioning did not significantly change the motion of the two joints, additional sectioning of the ITCL significantly increased adduction and total rotation of the ankle joint. The present study demonstrated that a combined injury of the ATFL and the ITCL can induce anterolateral rotatory instability of the ankle joint under conditions of axial loading.     

Comparative results of conservative treatments for isolated anterior talofibular ligament (ATFL) injury and injury to both the ATFL and calcaneofibular ligament of the ankle as assessed by subtalar arthrography

Background There have been no reports describing the results of conservative treatment of acute lateral ligament injury of the ankle in detail in terms of the severity of the injury, and the results of conservative treatment for injury with severe instability are still controversial. The purpose of this study was to assess the results of nonoperative treatment of acute lateral ligament injury according to its severity. Methods Fifty-five consecutive acute lateral ankle ligament injuries in 54 patients who were treated nonoperatively were followed up as a prospective study. Twenty-seven were male patients and 27 were female patients; the average age was 23.9 years (12–55 years). The patients were divided into two groups according to the extent of the ligament injury: patients with an isolated injury of the anterior talofibular ligament and those with combined injuries of the anterior talofibular ligament and the calcaneofibular ligament. In addition to the routine examinations for inversion ankle sprain, subtalar arthrography was mainly used to assess the condition of the calcaneofibular ligament. The arthrography was performed an average of 3.5 days after the injury (0–5 days). Results Fifty-five ankles of patients who were treated nonoperatively according to the same protocol were included in this study, and were followed up for an average of 5.0 years (37–86 months). At the time of the final follow-up, 22 of 25 (88%) ankles with an isolated injury to the anterior talofibular ligament were asymptomatic; in contrast, only 9 of 30 (30%) ankles with combined injuries of the anterior talofibular and calcaneofibular ligament were asymptomatic. The average American Orthopaedic Foot and Ankle Society score of the isolated injuries was 97.8 points, in contrast to 92.4 points for the combined injuries. Conclusions The results of nonoperative treatment with 1 week immobilization followed by a functional brace were excellent in patients with an isolated injury of the anterior talofibular ligament, but were unsatisfactory in those with combined injuries of the anterior talofibular and calcaneofibular ligaments.     

Plantaris tendon reconstruction of the lateral ankle ligaments

Numerous procedures have evolved to operatively stabilize the ankle suffering from chronic inversion instability. The use of the plantaris tendon to anatomically reconstruct the lateral collateral ankle ligaments is among those that avoid the complication of restriction of subtalar joint range of motion. The authors present a modified technique of reconstructing the calcaneofibular and anterior talofibular ligaments using a plantaris tendon that maintains its insertion. A retrospective study of eight patients that elected the procedure for chronic ankle instability was conducted. The average follow-up was 12.7 months. Significant improvement in functional score (p less than 0.01) and talar tilt (p less than 0.05) was noted following the procedure. No restriction of subtalar joint motion was observed in any patient after the procedure. The advantages and disadvantages of the procedure are discussed. The authors conclude that the procedure appears to be a desirable alternative in achieving ankle stability while maintaining normal hindfoot function.     

Experimental instability of the ankle. A radiographic investigation

For determination of the optimal position in examining the ankle joint for anterior drawer sign and talar tilting, 12 legs freshly amputated above the knee were radiographically examined after successive transection of the lateral ankle ligaments in three different sequences. Apparatuses secured the position of the ankle joint in 25 degrees of inward rotation and 10 degrees and 30 degrees, respectively, of plantarflexion. Examination for anterior drawer sign gave significantly greater displacement with the foot in 10 degrees than with the foot in 30 degrees of plantarflexion and was most pronounced after the cutting of the anterior talofibular ligament. Examination for talar tilt gave a non-significantly greater displacement at 10 degrees of plantarflexion, except when cutting both the posterior talofibular and the anterior talofibular ligament. Isolated cutting of the calcaneofibular ligament gave only little displacement irrespective of the method used. Radiographic examination should be performed with 10 degrees of plantarflexion to obtain maximal displacement and 25 degrees of inward rotation of the leg to obtain a free ankle mortise in the anteroposterior projection and concentric arcs of the joint surfaces in the side projection.