A radiological analysis of lateral ligament injuries of the ankle

Patients who presented within 5 days of an inversion injury to the ankle joint, were clinically selected for early radiological investigation and diagnosis of rupture of the lateral ligament of the ankle. Stress tenography was performed in 142 cases, and normal ranges for talar tilt and anterior draws were established in 216 normal ankles. In addition 38 cadaveric ankles were examined by peroneal tenography. No normal connection between the tendon sheath and the ankle joint was demonstrated. Sixty-five patients had positive peroneal tenograms; nine of these were positive only after manipulation. No complications occurred. Surgery was performed on 20 patients and demonstrated that common peroneal tenography was 95% accurate in diagnosing rupture of the calcaneo-fibular ligament. Of the 19 patients with proven calcaneo-fibular ligament rupture, six had a positive anterior draw sign, and nine had talar tilt. In this series both the talar tilt and anterior draw signs were found to be inaccurate. Common peroneal tenography is recommended as the method of choice for demonstrating acute rupture of the calcaneo-fibular component of the lateral ligament.     

Reconstruction of the lateral ankle ligaments. A biomechanical analysis.

The purpose of this study was to perform a biomechanical analysis of several commonly performed operative procedures used to stabilize the lateral ankle. We performed the Evans, Watson-Jones, and Chrisman-Snook procedures on 15 cadaveric ankles and tested the ankles for stability, motion, and isometry of graft placement. The Evans procedure allowed increased anterior displacement, internal rotation, and tilt of the talus when compared to ankles with intact ligaments. Subtalar joint motion was restricted by the Evans procedure. The Watson-Jones procedure controlled internal rotation and anterior displacement of the talus, but was less effective in controlling talar tilt and also restricted subtalar joint motion. The Chrisman-Snook procedure allowed increased internal rotation and anterior displacement of the talus when compared to ankles with intact ligaments. The procedure was effective in limiting talar tilt, but restricted subtalar joint motion. Based on the biomechanical data obtained, we devised a lateral ankle reconstruction with bone tunnels that reproduce the anatomic orientation of both the anterior talofibular and calcaneofibular ligaments. This ankle ligament reconstruction resists anterior displacement, internal rotation, and talar tilt without restricting subtalar joint motion. Clinical relevance: We found considerable mechanical differences among the more commonly performed lateral ankle reconstructions. It is possible to locate bone tunnels and graft placement so that a more anatomic configuration is achieved.     

Diagnostic value of stress radiography in lesions of the lateral ligaments of the ankle

The diagnostic accuracy of inversion and anterior stress radiography in rupture of the lateral ligaments of the ankle joint was assessed in 56 patients undergoing surgery. In inversion stress radiography, 58 per cent of the patients with confirmed rupture of the lateral ligaments of the ankle had a talar tilt of 10 degrees or more, allowing a predictive value of a positive test of 94 per cent. In anterior stress radiography, 53 per cent of the patients had a posterior tibiotalar distance of 9 mm or more, allowing a predictive value of a positive test of 81 per cent. In measurements of talar tilt and anterior displacement of the talus values higher than normal in the injured ankle may be a sign of a rupture of the lateral ligament.     

The accuracy of three-dimensional magnetic resonance imaging in the diagnosis of ruptures of the lateral ligaments of the ankle.

In a prospective study, the diagnostic accuracy of three-dimensional magnetic resonance imaging in the evaluation of ruptures of the lateral ligaments of the ankle was determined by comparing three-dimensional magnetic resonance findings with operative findings. In a series of 18 consecutive cases of acute significant inversion trauma to the ankle, a three-dimensional fast imaging with steady-state precession pulse sequence (3D FISP) was performed. The study included only those cases in which views showed a difference in talar tilt of 15 degrees or more, and a difference in anteroposterior drawer of 10 mm or more between the imaged and the normal ankle. All ankles were scheduled for surgical exploration. Compared with operative findings, the sensitivity, specificity, and accuracy of 3D FISP imaging were, respectively, 100%, 50%, and 94.4% for ruptures of the anterior talofibular ligament and 91.7%, 100%, and 94.4% for ruptures of the calcaneofibular ligament. We believe that 3D FISP magnetic resonance imaging is a noninvasive, fast, and very accurate diagnostic aid to operative planning for double ligament tears in younger competitive athletes.     

半腱肌移植重建踝关节外侧副韧带及踝关节不稳

目的 探讨半腱肌移植修复陈旧性踝关节外侧副韧带损伤及踝关节不稳的有效性.方法 选择陈旧性踝关节外侧副韧带损伤患者2例,其中男1例,女1例;男25岁,女17岁.左侧1例,右侧1例.患者入院前均有2年以上反复踝部旋后位扭伤的病史.踝部损伤为Ⅲ度(美国足踝外科学院分度);前抽屉试验及距骨倾斜试验阳性.应力X线片显示距骨倾斜平均21°,且在侧位片显示距骨前脱位.2例均采用同侧自体半腱肌肌腱移植重建踝关节外侧副韧带.结果 2例平均随访8个月.患足局部无肿痛,行走正常,踝关节主动活动与被动活动良好,患足前抽屉试验及距骨倾斜试验阴性,应力X线片检查显示距骨无前脱位,距骨倾斜角＜5°.根据Mazur疗效评分标准,优1例,良1例.患者对踝关节功能主观满意.结论 (1)踝关节外侧副韧带损伤是导致慢性踝关节不稳,甚至踝关节骨性关节炎的常见原因;(2)Brostr(o)m法仍不失为修复新鲜踝关节外侧副韧带损伤的有效方法,但对陈旧性损伤无效.(3)采用自体半腱肌肌腱修复重建陈旧性踝关节外侧副韧带的方法简单,有效,对于治疗踝关节不稳、防止踝关节骨性关节炎的发生具有重要的作用.     

Anatomic reconstruction of the anterior talofibular and calcaneofibular ligaments using a semitendinosus tendon allograft and interference screws

Purpose

The purpose of this study was to evaluate the functional and radiographic outcomes of a novel surgical technique devised to treat chronic lateral ankle instability. The technique involves direct repair of the anterior talofibular ligament and anatomic reconstructions of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) using a free semitendinosus tendon allograft and interference screws.

Methods

This retrospective study involved a review of the records of 27 patients (28 ankles) with chronic lateral ankle instability treated from 2007 to 2009. VAS pain scores, AOFAS scores, Karlsson–Peterson ankle scores (24 ankles), and patient satisfaction were evaluated at median of 19 (12–26)?months postoperatively. Radiographically, talar tilt angles and anterior talar translation were assessed in pre- and postoperative ankle stress views.

Results

Median patient age at surgery was 36.5 (16–57)?years. Median VAS pain score decreased from 6 (3–9) to 2 (0–4) (P?P?P?P?Conclusions The described technique, which involves anatomic reconstruction of the ATFL and CFL using the semitendinosus tendon and interference screws with direct repair of the capsule, is a viable option for treating lateral ankle instability with stable tendon fixation and provides satisfactory clinical outcomes.

Level of evidence

Case-series, Level IV.     

Anterior–posterior mobility of the talus in subjects with chronic ankle instability

ObjectivesThe effect of hypermobility or hypomobility of the talus in subjects with chronic ankle instability (CAI) has not been fully elucidated. The purpose of this study was to determine the anterior–posterior mobility of the talus in subjects with CAI.DesignRetrospective case–control study.SettingAthletic training research laboratory.ParticipantsFifteen subjects with unilateral CAI, and 15 subjects with no previous history of ankle injury participated in this study.Main outcomes measuresAnterior talar laxity was assessed with manual anterior drawer test and anterior drawer stress radiographs. Posterior talar hypomobility was assessed with a series of two posterior talar glide manual tests. Comparisons were made between the CAI and control groups and within sides of both groups.ResultsThe CAI group (mean=11.4±5.4 mm) had significantly more anterior talar displacement on both their ankles as measured on the stress views than did the control group (mean=6.7±4.7 mm). Interestingly, there was very little side to side difference between the involved and uninvolved ankles of the CAI group (11.5±5.6 vs. 11.3±5.4 mm). There were no significant differences involving either of the posterior talar glide measures or of the manual anterior drawer test.ConclusionsAn increased amount of anterior talar mobility was demonstrated in the CAI group. Although all of our subjects reported unilateral CAI, increased laxity was present in both their unstable and healthy ankles.     

The effect of external ankle support in chronic lateral ankle joint instability. An electromyographic study.

We examined the effect of ankle taping on ankle joint stability by measuring mechanical stability using standardized stress radiographs. Anterior talar translation and talar tilt, both with and without ankle tape, were examined. The reduction of anterior talar translation and talar tilt with tape as compared to without tape was insignificant. The reaction time of the peroneus muscles was measured by electromyographic signal after a simulated ankle sprain on a tilting trapdoor. The reaction time was significantly slower in the unstable ankles of 20 athletes with unilateral ankle instability than in the stable contralateral ankles. With tape, the reaction time was significantly shortened, although not back to normal. The greatest improvement in reaction time was achieved in ankles with the highest degree of mechanical instability. Thus, the mechanism behind the function of ankle tape may be to restrict the extremes of ankle motion and to help shorten the reaction time of the peroneus muscles by affecting the proprioceptive function of the ankle.     

Quantitative assessment of mechanical laxity in the functionally unstable ankle

PURPOSE: Delineating between functional and mechanical instability in those with chronic ankle dysfunction is a challenging task. Current methods of assessing ankle ligamentous laxity are subjective in nature and limit our ability to identify the site and extent of instability; therefore, a need exists for objective laxity measurements. The purpose of this study was to determine whether subjects with self-reported, functional ankle instability (FAI) demonstrated increased mechanical laxity when tested with instrumented arthrometry and stress radiography. METHODS: Both ankles were tested in 51 subjects with self-reported unilateral FAI. An instrumented ankle arthrometer measured ankle-subtalar joint motion for total anteroposterior (AP) displacement (mm) during loading at 125 N and total inversion-eversion (I-E) rotation (degrees of ROM) during loading at 4 N x m. The Telos GA-II/E device provided either anterior or lateral stress (15 kp) while fluoroscopic radiographs were recorded for anterior displacement (mm) and talar tilt (degrees). RESULTS: The arthrometry measurements of anterior and total AP displacement and the radiographic measurements of anterior displacement were greater (P < 0.05) in the FAI ankles when compared with the uninjured ankles. There were no differences in total I-E rotation, inversion rotation, or talar tilt between ankles when analyzed with either measurement technique. CONCLUSION: The ability to objectively measure mechanical instability in the functionally unstable ankle is important to understanding the nature and cause of the instability. Ankle arthrometry and stress radiographic measurements are objective assessment tools for mechanical laxity. Despite finding greater laxity in the functionally unstable ankle, the clinical significance of the observed displacement remains unanswered. Further research is needed to determine the amount of laxity that constitutes mechanical instability and how this relates to FAI.     

Clinical evaluation of a dynamic test for lateral ankle ligament laxity

The dynamic anterior ankle tester (DAAT) has shown a good reliability in testing anterior talar translation in earlier studies. The goal of the present study was first to evaluate the reliability of the DAAT in a clinical setting and second to analyze its ability to detect increased ligament laxity. In 39 patients with unilateral chronic lateral ankle instability, the anterior talar translation of the affected and non-affected side was measured pre and postoperatively using the DAAT, Telos stress radiographs, and the manual anterior drawer test. In contrast to both other tests, the DAAT was not able to accurately detect increased ligament laxity preoperatively or decreased laxity of the affected ankle postoperatively. The DAAT showed a low sensitivity to change (the difference between the mean pre and postoperative value) and a low reliability compared to both other tests. There were no correlations between the three tests. In conclusion, the DAAT showed a low reliability in effectively testing lateral ankle ligament laxity in a clinical setting. This is in contrast to earlier evaluations.     

Mechanical ankle stabilisation due to the use of orthotic devices and peroneal muscle strength. An experimental investigation.

The mechanical stabilising effect of different orthotic devices and artificially applied muscular strength to the peroneal muscles is tested in cadaveric ankle joints and in vivo. Both orthotic devices as well as muscular strengths of 150 N applied to the peroneal muscles can produce a significant reduction in mechanical ankle instability. However, none of these methods alone can stabilise the ankle joint in such way to completely normalise the talar tilt and anterior drawer sign that is found in stable ankle joints. In contrast to that, clinical results in the treatment of sprained ankles with the application of an orthosis, additional muscular strengthening is the best treatment to achieve a sufficient mechanical ankle stability during the period of ligament healing. Additional factors influencing the mechanical ankle stability are supposed.     

Value of stress ultrasound for the diagnosis of chronic ankle instability compared to manual anterior drawer test,stress radiography,magnetic resonance imaging,and arthroscopy

Purpose

Clinicians frequently diagnose chronic ankle instability using the manual anterior drawer test and stress radiography. However, both examinations can yield incorrect results and do not reveal the extent of ankle instability. Stress ultrasound has been reported to be a new diagnostic tool for the diagnosis of chronic ankle instability. The purpose of this study was to assess the diagnostic value of stress ultrasound for chronic ankle instability compared to the manual anterior drawer test, stress radiography, magnetic resonance imaging (MRI), and arthroscopy.

Methods

Twenty-eight consecutive patients who underwent ankle arthroscopy and subsequent modified Broström repair for treatment of chronic ankle instability were included. The arthroscopic findings were used as the reference standard. A standardized physical examination (manual anterior drawer test), stress radiography, MRI, and stress ultrasound were performed to assess the anterior talofibular ligament (ATFL) prior to operation. Ultrasound images were taken in the resting position and the maximal anterior drawer position.

Results

Grade 3 lateral instability was verified arthroscopically in all 28 cases with a clinical diagnosis (100 %). Twenty-two cases showed grade III instability on the manual anterior drawer test (78.6 %). Twenty-four cases displayed anterior translation exceeding 5 mm on stress radiography (86 %), and talar tilt angle exceeded 15° in three cases (11 %). Nineteen cases displayed a partial chronic tear (change in thickness or signal intensity), and nine cases displayed complete tear on MRI (100 %). Lax and wavy ATFL was evident on stress ultrasound in all cases (100 %). The mean value of the ATFL length was 2.8 ± 0.3 cm for the stressed condition and 2.1 ± 0.2 cm for the resting condition (p < 0.001).

Conclusion

Stress ultrasound may be useful for the diagnosis of chronic ankle instability in addition to the manual anterior drawer test and stress radiography.

Level of evidence

III.

     

Arthroscopic findings in chronic lateral ankle instability: do focal chondral lesions influence the results of ligament reconstruction?

BACKGROUND: There are few studies that have assessed the influence of focal chondral lesions on the results of ligament reconstruction for chronic lateral ankle instability. HYPOTHESIS: Focal chondral lesions do not influence the results of ligament reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Arthroscopic examination of the ankle was performed on 30 consecutive patients immediately before ligament reconstruction using the palmaris longus tendon. Clinical assessment was performed using the Karlsson scoring scale. A radiologic assessment was performed on stress radiographs of the ankle. Preoperative anteroposterior and lateral weightbearing radiographs of the ankle did not show any joint space narrowing in any ankle. The mean duration of follow-up was 38 months. RESULTS: On arthroscopy, focal chondral lesions were found in 19 ankles (63%). Chondral lesions were located on the medial side of the tibial plafond in 13 ankles (43%), on the lateral side in 2 ankles (7%), on the lateral side of the talar dome in 3 ankles (10%), and on the medial side in 9 ankles (30%). Postoperative mean Karlsson scores in patients without chondral lesions and in those with chondral lesions were 99.1 and 98.4 points, respectively. Postoperative mean talar tilt angles in patients without chondral lesions and in those with chondral lesions were 5.9 degrees and 4.7 degrees , respectively. There were no significant differences in the clinical and radiologic results between patients with chondral lesions and those without chondral lesions. CONCLUSIONS: Reconstruction of the lateral ligament can be successful regardless of the presence of focal chondral lesions in patients with chronic lateral ankle instability when preoperative weightbearing radiographs of the ankle do not show any joint space narrowing.     

Relationship between stress ankle radiographs and injured ligaments on MRI

Objective

This study was performed to investigate the relationship between the injured lateral ankle ligaments on MRI and stress ankle radiographs.

Materials and methods

Two hundred and twenty-nine consecutive patients (mean age 35.5 years, SD 14.6 years; 136 males and 93 females) that underwent ankle stress radiographs and MRI for lateral ankle instability were included. Tibiotalar tilt angle and anterior translation of talus were measured on stress ankle radiographs. Degree of lateral ligaments (anterior talofibular, calcaneofibular, and posterior talofibular) and deltoid ligament injuries were evaluated and scored as intact (0), partial injury (1), and complete injury (2) on MR images. Effusion of ankle joint was also recorded. The effects of gender, age, injuries of ligaments, and ankle joint effusion on stress radiographs were statistically analyzed.

Results

Gender (p?=?0.010), age (p?=?0.020), and anterior talofibular ligament (ATFL) injury (p?<?0.001) were the factors significantly affecting tibiotalar tilt angle. Posterior talofibular ligament (PTFL) injury (p?=?0.014) was found to be the only significant factor affecting the anterior translation on the anterior drawer radiographs.

Conclusions

ATFL injury and PTFL injury on MRI significantly affected tibiotalar tilt angle and anterior drawer on stress radiographs. Other factors, such as age and gender, need to be considered in evaluating radiographic lateral ankle instability.     

Diagnostic accuracy of instrumented and manual talar tilt tests in chronic ankle instability populations

Diagnostic accuracy of the talar tilt test is not well established in a chronic ankle instability (CAI) population. Our purpose was to determine the diagnostic accuracy of instrumented and manual talar tilt tests in a group with varied ankle injury history compared with a reference standard of self‐report questionnaire. Ninety‐three individuals participated, with analysis occurring on 88 (39 CAI, 17 ankle sprain copers, and 32 healthy controls). Participants completed the Cumberland Ankle Instability Tool, arthrometer inversion talar tilt tests (LTT), and manual medial talar tilt stress tests (MTT). The ability to determine CAI status using the LTT and MTT compared with a reference standard was performed. The sensitivity (95% confidence intervals) of LTT and MTT was low [LTT = 0.36 (0.23–0.52), MTT = 0.49 (0.34–0.64)]. Specificity was good to excellent (LTT: 0.72–0.94; MTT: 0.78–0.88). Positive likelihood ratio (+ LR) values for LTT were 1.26–6.10 and for MTT were 2.23–4.14. Negative LR for LTT were 0.68–0.89 and for MTT were 0.58–0.66. Diagnostic odds ratios ranged from 1.43 to 8.96. Both clinical and arthrometer laxity testing appear to have poor overall diagnostic value for evaluating CAI as stand‐alone measures. Laxity testing to assess CAI may only be useful to rule in the condition.     

Talocrural and subtalar joint instability after lateral ankle sprain

PURPOSE: Recurrence of lateral ankle sprain (LAS) is common among recreational and competitive athletes. Talocrural (TC) joint laxity has traditionally been seen as the cause of mechanical instability after LAS. The purpose of this study was to examine the use of stress fluoroscopy and physical examination in the assessment of TC and subtalar (ST) instability in subjects with and without a history of LAS. METHODS: Twelve subjects with a history of unilateral LAS and eight healthy controls were examined by two blinded examiners. The first examiner performed physical examination on each ankle by using the anterior drawer (AD), talar tilt (TTPE), and medial subtalar glide (MSTG) tests. Laxity in each ankle was assessed on a 4-point scale. The second examiner performed stress fluoroscopy taking AP views with and without a manually applied supination stress to assess TC laxity and a sidelying modified Broden view with and without stress to assess ST laxity. Subjective examination of the images was used to determine excessive TC and ST laxity. RESULTS: Seventy-five percent of previously injured subjects demonstrated unilateral laxity differences of the TC joint using stress fluoroscopy. Of the nine with excessive talar tilt on fluoroscopy, 78% demonstrated excessive laxity with the AD and MSTG tests, and 67% demonstrated laxity with the TTPE test. Sixty-seven percent of those with TC laxity also demonstrated either excessive unilateral or bilateral laxity of the ST joint under stress fluoroscopy. CONCLUSIONS: These data suggest the existence of a subpopulation of patients with a history of LAS who demonstrate a pattern of combined TC and ST laxity.     

中国青年距骨斜角正常值测定

目的 :测定中国健康青年踝关节距骨斜角正常值范围 ,从影像学方面提供急性外踝韧带损伤导致外踝不稳的定量诊断方法。方法 :随机选择无外踝韧带损伤史的健康青年学生 2 2 4人(男 1 1 8人 ,女 1 0 6人 ) ,年龄 2 0～2 3岁 ,共计 445例踝关节。在髋、膝屈曲 90°、踝跖屈 3 0°位 ,采用踝关节加压内翻拍片架拍踝跖屈内翻应力正位X线片。结果 :445例踝关节中 ,距骨斜角最小 0°,最大 1 1°,男性踝关节 2 3 5例距骨斜角 x±s为 3 99°± 1 91°,M±Q为 4°± 2°,P95为 7°;女性踝关节2 1 0例距骨斜角 x±s为 4 3 9°± 2 2 3°,M±Q为 4°±3°,P95为 8°。结论 :中国健康青年踝关节距骨斜角正常值范围为 0°～8°,急性外踝韧带损伤患者距骨斜角 >4°而≤ 8°时 ,结合临床严重的体征可考虑韧带断裂 ,距骨斜角 >8°时 ,可认为至少有一条外踝韧带断裂     

Examination of the sprained ankle: anterior drawer test or arthrography?

The accuracy of the anterior drawer test for the diagnosis of recent lateral ligament tears in the ankle was evaluated in a series of 192 patients using surgical or arthrographic findings for reference. Considerable overlapping of results was obtained in ankles with and without ligament tear. Twenty-eight per cent of the anterior talofibular ligament tears, and 38% of the combined anterior talofibular and calcaneofibular tears were not detected, and single and combined tears could not be differentiated. It is concluded that the anterior drawer test is too unreliable as a basis for any decision regarding surgical treatment of a recent sprain. Therefore, arthrography is recommended as the method of choice in such cases of recent ankle sprain, where the need of surgery has to be supported by X-ray analysis.     

Effectiveness of functional ankle taping for judo athletes: a comparison between judo bandaging and taping.

This study was conducted to compare the effectiveness of the traditional method of ankle bandaging and the new method of ankle taping for judo athletes in Japan, and to introduce a functionally effective taping method for judo players. Four university judo athletes with ankle instability were selected to undertake radiography of the ankles before and after exercise, with bandaging at one time and taping at the other. Talar tilt (TT) angles were measured in order to compare the ankle-supporting effects. The results showed that the old ankle bandaging method had no role in eliminating the talar tilt during judo practice. In contrast, the new taping method was more effective in eliminating the talar tilt and supporting the involved ankles both mechanically and functionally.     

Biomechanical evaluation against calcaneofibular ligament repair in the Brostrom procedure: a cadaveric study

The modified Brostrom procedure is commonly recommended for reconstruction of the anterior talofibular ligament (ATF) and calcaneofibular ligament (CF) with an advancement of the inferior retinaculum. However, some surgeons perform the modified Bostrom procedure with an semi-single ATF ligament reconstruction and advancement of the inferior retinaculum for simplicity. This study evaluated the initial stability of the modified Brostrom procedure and compared a two ligaments (ATF + CF) reconstruction group with a semi-single ligament (ATF) reconstruction group. Sixteen paired fresh frozen cadaveric ankle joints were used in this study. The ankle joint laxity was measured on the plane radiographs with 150 N anterior drawer force and 150 N varus stress force. The anterior displacement distances and varus tilt angles were measured before and after cutting the ATF and CF ligaments. A two ligaments (ATF + CF) reconstruction with an advancement of the inferior retinaculum was performed on eight left cadaveric ankles, and an semi-single ligament (ATF) reconstruction with an advancement of the inferior retinaculum was performed on eight right cadaveric ankles. The ankle instability was rechecked after surgery. The decreases in instability of the ankle after surgery were measured and the difference in the decrease was compared using a Mann-Whitney U test. The mean decreases in anterior displacement were 3.4 and 4.0 mm in the two ligaments reconstruction and semi-single ligament reconstruction groups, respectively. There was no significant difference between the two groups (P = 0.489). The mean decreases in the varus tilt angle in the two ligaments reconstruction and semi-single ligament reconstruction groups were 12.6 degrees and 12.2 degrees , respectively. There was no significant difference between the two groups (P = 0.399). In this cadaveric study, a substantial level of initial stability can be obtained using an anatomical reconstruction of the anterior talofibular ligament only and reinforcement with the inferior retinaculum. The modified Brostrom procedure with a semi-single ligament (Anterior talofibular ligament) reconstruction with an advancement of the inferior retinaculum can provide as much initial stability as the two ligaments (Anterior talofibular ligament and calcaneofibular ligament) reconstruction procedure.