Two ankle joint laxity testers: reliability and validity

Two test devices were manufactured to objectively measure ankle joint laxity: the dynamic anterior ankle tester (DAAT) and the quasi-static anterior ankle tester (QAAT). The primary aim was to analyse the reliability of both testers; The secondary aim was to assess validity in correlation with TELOS stress test and manual anterior drawer test. Twenty-four normal subjects and 14 patients 1 year after acute lateral ankle ligament injury were included. Both ankles were tested with the DAAT and QAAT by two different observers; one experienced orthopaedic surgeon performed the manual test; the TELOS stress X-rays were evaluated by one observer. Intra observer reliability for the DAAT varied between 0.81 and 0.94; for the QAAT between 0.71 and 0.94. Inter observer reliability for the DAAT varied between 0.84 and 0.94; for the QAAT between 0.76 and 0.82. Concurrent validity showed fair correlation between DAAT and QAAT for the first couple observers (0.71); however, a poor correlation was observed for the second couple (0.42). No significant correlations were found between neither DAAT and the TELOS and the manual test, nor QAAT and the TELOS and the manual test. In conclusion, reliability of both testers is high. Validity of the testers needs further investigation.     

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.     

Measurement of posterior tibial translation in the posterior cruciate ligament-reconstructed knee: significance of the shift in the reference position

BACKGROUND: The measurement of anterior or posterior tibial translation depends on the existence of a repeatable and accurate reference position of the knee from which the corresponding translation is measured. HYPOTHESIS: Clinical measurements of posterior tibial translation alone do not accurately reflect the laxity of posterior cruciate ligament-reconstructed knees. STUDY DESIGN: Controlled laboratory study. METHODS: Ten human cadaveric knees were tested by using a robotic/universal force-moment sensor testing system. The reference positions and the resulting kinematics in response to a 134-N anterior-posterior tibial load were determined for the intact and reconstructed knees. Posterior cruciate ligament reconstruction was performed with the graft tensioned and fixed at two different positions: 1) 90 degrees of knee flexion with a 134-N anterior tibial load and 2) full extension with no load. RESULTS: Posterior cruciate ligament reconstruction with graft fixation at full extension with no load resulted in anterior shift of the reference position by 1.5 to 3.2 mm. The reconstruction resulted in an overconstrained knee with significantly decreased total anterior-posterior translation of 2.6 to 3.2 mm. However, the posterior tibial translation measured was not significantly different from that of the intact knee. Posterior cruciate ligament reconstruction with graft fixation performed at 90 degrees of flexion with a 134-N anterior tibial load resulted in kinematics similar to those of the intact knee. CONCLUSION: Posterior tibial translations that are measured clinically can be misleading because the reference position of the knee can be shifted significantly after posterior cruciate ligament reconstruction. Clinical Relevance: The measurement of total anterior-posterior translation may be a more accurate way to assess kinematics of the reconstructed knee.     

Surgical treatment of lateral ankle instability syndrome

Lateral ankle instability syndrome is defined by pain and instability caused by ligament laxity. Anterior talofibular ligament laxity, with or without calcaneofibular laxity and other abnormalities, is often present in conjunction with peroneus brevis tendon tears, abnormal ligament placement, tibialis posterior tendon tears, osteochondritis dissecans, arthritis, synovitis, loose bodies, and tarsal coalition. Surgical reconstructions were performed on 43 ankles using a split peroneus brevis tendon graft routed through osseous tunnels in the talus, fibula, and calcaneus and resutured to the reconstructed anterior talofibular and calcaneofibular ligaments. The tunnel locations, transfer routes, and tendon reinforcement were modifications based on the Elmslie procedure. Good and excellent results were achieved in 91% of the patients. Ninety-eight percent of the patients achieved stability. Followup was from 9 months to 11 years. Twenty-one patients had preoperative and intraoperative findings that required additional procedures. Thorough evaluation of patients with lateral ankle instability syndrome increases the frequency of finding associated abnormalities, which if left uncorrected, may adversely affect the outcome of surgery.     

Kinematics and laxity of the knee joint after anterior cruciate ligament reconstruction: pre- and postoperative radiostereometric studies

BACKGROUND: Injury of the anterior cruciate ligament changes the kinematics of the knee joint. In studies of cadaveric knees, investigators have examined the effect of anterior cruciate ligament reconstruction on knee kinematics, but the effect on dynamic knee motion is not known. HYPOTHESIS: Reconstruction of the anterior cruciate ligament restores knee kinematics to normal. STUDY DESIGN: Prospective cohort study. METHODS: Nine patients were examined preoperatively and 1 year after reconstruction. Continuous radiostereometric exposures were performed at a speed of two to four exposures per second while the patients ascended an 8-cm high platform. Tibial rotation and tibial and femoral translation were measured with radiostereometric analysis. RESULTS: Tibial rotation and tibial and femoral translation were not significantly different after anterior cruciate ligament reconstruction compared with preoperative measurements. A radiostereometric evaluation of anterior knee laxity revealed restoration to within 1 mm of that on the uninjured side. Further evaluation of knee function using the Lysholm score, the Tegner activity level score, the International Knee Documentation Committee evaluation system score, and measurements of laxity using the KT-1000 arthrometer revealed significant improvements after reconstruction. CONCLUSION: Kinematics of the anterior cruciate ligament injured knee did not change significantly after ligament reconstruction, but the functional results were satisfactory and knee laxity was diminished.     

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.     

The effect of anterior cruciate ligament reconstruction on knee joint kinematics under simulated muscle loads

BACKGROUND: Numerous studies have investigated anterior stability of the knee during the anterior drawer test after anterior cruciate ligament reconstruction. Few studies have evaluated anterior cruciate ligament reconstruction under physiological loads. PURPOSE: To determine whether anterior cruciate ligament reconstruction reproduced knee motion under simulated muscle loads. STUDY DESIGN: Controlled laboratory study. METHODS: Eight human cadaveric knees were tested with the anterior cruciate ligament intact, transected, and reconstructed (using a bone-patellar tendon-bone graft) on a robotic testing system. Tibial translation and rotation were measured at 0 degrees, 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion under anterior drawer loading (130 N), quadriceps muscle loading (400 N), and combined quadriceps and hamstring muscle loading (400 N and 200 N, respectively). Repeated-measures analysis of variance and the Student-Newman-Keuls test were used to detect statistically significant differences between knee states. RESULTS: Anterior cruciate ligament reconstruction resulted in a clinically satisfactory anterior tibial translation. The anterior tibial translation of the reconstructed knee was 1.93 mm larger than the intact knee at 30 degrees of flexion under anterior load. Anterior cruciate ligament reconstruction overconstrained tibial rotation, causing significantly less internal tibial rotation in the reconstructed knee at low flexion angles (0 degrees-30 degrees) under muscle loads (P < .05). At 30 degrees of flexion, under muscle loads, the tibia of the reconstructed knee was 1.9 degrees externally rotated compared to the intact knee. CONCLUSIONS: Anterior cruciate ligament reconstruction may not restore the rotational kinematics of the intact knee under muscle loads, even though anterior tibial translation was restored to a clinically satisfactory level under anterior drawer loads. These data suggest that reproducing anterior stability under anterior tibial loads may not ensure that knee joint kinematics is restored under physiological loading conditions. CLINICAL RELEVANCE: Decreased internal rotation of the knee after anterior cruciate ligament reconstruction may lead to increased patellofemoral joint contact pressures. Future anterior cruciate ligament reconstruction techniques should aim at restoring 3-dimensional knee kinematics under physiological loads.     

Anterior drawer test for acute anterior talofibular ligament injuries of the ankle. How much load should be applied during the test?

BACKGROUND: There is a lack of consensus regarding the magnitude of load for performing the anterior drawer test in evaluating acute ankle injuries. PURPOSE: To determine how much load should be applied during the anterior drawer test to detect the integrity of the anterior talofibular ligament. METHODS: First, the anterior-posterior load-displacement response of nine cadaveric ankles was measured. Second, anterior displacement of the ankle was measured at 30 and 60 N of anterior load in 14 patients with acute tears of the anterior talofibular ligament. RESULTS: In the cadaver study, the increased displacement by sectioning of the ligament measured at 10, 20, 30, and 40 N of anterior load were significantly greater than those measured at 60 N. In vivo examination of the subjects without anesthesia demonstrated that the injured-to-normal displacement value at 30 N of anterior load was significantly greater than the value at 60 N. CONCLUSIONS: This study suggests that a large magnitude of anterior load is not necessary to detect the integrity of the ligament during the anterior drawer test. CLINICAL RELEVANCE: When evaluating the integrity of the anterior talofibular ligament in cases of acute ankle ligament injury, a relatively low-magnitude load should be applied.     

Weight-bearing knee kinematics in subjects with two types of anterior cruciate ligament reconstructions

Weight-bearing knee kinematics in patients who received two types of anterior cruciate ligament reconstruction were studied using a fluoroscopy-based three-dimensional measurement technique. Eleven patients with more than 1-year follow-up and good or excellent results participated in this study. Six subjects received anterior cruciate ligament reconstruction using a multiply folded semitendinosus and gracilis tendon graft, and five received combined intra- and extra-articular anterior cruciate ligament reconstruction using the iliotibial tract. The step up/down activity of normal and operated knees was recorded using lateral fluoroscopy. A customized three-dimensional contour model was created from two orthogonal views of each knee and all six degrees of freedom of knee movement were determined using a model matching technique. Both the normal and the reconstructed knees exhibited posterior condylar translation and internal tibial rotation with knee flexion, consistent with previous reports of normal kinematics. There were no statistically significant differences in the axial rotations or lateral or medial condylar anterior/posterior translations between operated and normal knees or between the two groups of operated knees.     

Intraarticular anterior cruciate ligament graft placement on the average most isometric line on the femur. Does it reproducibly restore knee kinematics?

In the past, there has been a plausible hypothesis that anterior cruciate ligament graft placement at isometric sites, such that the tibial and femoral attachment sites remain equidistant from each other throughout knee range of motion, would increase the likelihood of a satisfactory outcome. For a given tibial placement we wanted to determine whether placing the graft on the average of the most isometric femoral line, a fixed distance from the outlet of the intercondylar notch, would return normal laxity to all knees. The three-dimensional kinematics of seven cadaveric knees were measured for angles from full extension to 90 degrees of flexion at 15 degrees increments. Physiologic levels of quadriceps muscle forces were applied to the intact knee, after transection of the anterior cruciate ligament, and after ligament reconstruction with a patellar tendon graft. On average, the reconstruction was found to return anterior-posterior translation, internal-external rotation, and varus-valgus rotation to levels not significantly different from those of the intact knee. However, the ranges of the translation and rotations were large. Placing the graft on the average most isometric femoral line did not restore knee laxity to normal in all knees. This supports the need to customize graft placement in each knee at the time of surgery.     

The effect of posterior cruciate ligament deficiency on knee kinematics

BACKGROUND: Alteration of the kinematics of the PCL-deficient knee might be a factor in producing the articular damage. Very little is known about the in vivo weightbearing kinematics of the PCL-deficient knee. HYPOTHESIS: Isolated rupture of the posterior cruciate ligament alters knee kinematics, predisposing the patient to development of early osteoarthritis. STUDY DESIGN: Case series. METHODS: Tibiofemoral motion was assessed using open-access magnetic resonance imaging, weightbearing in a squat, through the arc of flexion from 0 degrees to 90 degrees in 6 patients with isolated rupture of the posterior cruciate ligament in one knee and a normal contralateral knee. Passive sagittal laxity was assessed by performing the posterior and anterior drawer tests while the knees were scanned, again using the same magnetic resonance imaging scanner. The tibiofemoral positions during this stress magnetic resonance imaging examination were measured from midmedial and midlateral sagittal images of the knees. RESULTS: Rupture of the posterior cruciate ligament leads to an increase in passive sagittal laxity in the medial compartment of the knee (P < .006). In the weightbearing scans, posterior cruciate ligament rupture alters the kinematics of the knee with persistent posterior subluxation of the medial tibia so that the femoral condyle rides up the anterior upslope of the medial tibial plateau. This fixed subluxation was observed throughout the extension-flexion arc and was statistically significant at all flexion angles (P < .018 at 0 degrees , P < .013 at 20 degrees , P < .014 at 45 degrees , P < .004 at 90 degrees ). The kinematics of the lateral compartment were not altered by posterior cruciate ligament rupture. The posterior drawer test showed increased laxity in the medial compartment. CONCLUSION: Posterior cruciate ligament rupture alters the kinematics of the medial compartment of the knee, resulting in "fixed" anterior subluxation of the medial femoral condyle (posterior subluxation of the medial tibial plateau). This study helps to explain the observation of increased incidence of osteoarthritis in the medial compartment, and specifically the femoral condyle, in posterior cruciate ligament-deficient knees.     

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.     

New method of diagnosis for chronic ankle instability: comparison of manual anterior drawer test,stress radiography and stress ultrasound

Purpose

To diagnose chronic ankle instability, clinicians frequently use manual anterior drawer test and stress radiography. However, both exams can yield incorrect results and do not reveal the extent of ankle instability. The use of stress ultrasound during a manual anterior drawer stress procedure might enable the diagnosis of chronic ankle instability.

Methods

Seventy-three patients with chronic ankle pain or laxity after remote ankle sprain were included. The study population included 41 males and 32 females. The mean age of the patients at the time of the operation was 29 years. A standardized physical examination (manual anterior drawer test), stress radiography and stress ultrasonography were performed to assess the anterior talofibular ligament (ATFL). Ultrasound images were taken in the resting position and the maximal anterior drawer position. The statistical significance of stress ultrasound among the three groups according to manual anterior drawer test and a specific degree (5 mm) of anterior translation of stress radiography were analysed. Correlation coefficients between stress ultrasound, stress radiography and manual anterior drawer test were calculated.

Results

There was a significant difference for ATFL length (ATFL stress) and ATFL ratio (ATFL stress/ATFL resting) among the three groups (both p < 0.001). However, there was no significant difference for anterior translation of stress radiography among three groups according to manual anterior drawer test (p = 0.159). There was a significant difference for ATFL length (ATFL stress) and ATFL ratio between two groups with 5-mm anterior translation of stress radiography (p = 0.002 and p = 0.011, respectively). The mean value of grade of manual anterior drawer test between the two groups also differed (p = 0.021). There was a moderately positive linear relationship between stress ultrasound and manual anterior drawer test. Also, there was a positive linear relationship between stress ultrasound and stress radiography.

Conclusion

The results suggest that the value of ATFL length (ATFL stress) and ATFL ratio of stress ultrasound could be used for diagnosis of chronic ankle instability in addition to manual anterior drawer test and stress radiography.

Level of evidence

III.     

The relationships between instrumented measurements of ankle and knee ligamentous laxity and generalized joint laxity

AIM: The purpose of this study was to evaluate whether lower extremity joint laxity is a function of a particular joint and/or a generalizable characteristic (trait) of the person. Validated instrumented measurements of ankle and knee joint-specific laxity in the same individual were correlated to determine whether a relationship exists. In addition, ankle and knee joint-specific laxity were correlated with generalized joint laxity using the modified Beighton mobility index. METHODS: Fifty-seven male and female athletes were studied. We examined dominant ankle laxity using an ankle arthrometer and dominate knee anterior laxity using the KT 2000. The dominant ankle was loaded in anteroposterior (AP) drawer and inversion-eversion (I-E) rotation. Laxity was measured as total AP displacement (millimeters) after +/-125 N of applied force and total I-E rotation (degrees) was measured after +/-4 N x m of applied torque. The dominant knee was loaded with an anterior drawer and laxity (millimeters) was measured after manual maximum displacement. RESULTS: Non-significant correlations were observed among the test variables for generalized joint laxity (0.21 to 0.37; P>0.05) and instrumented ankle and knee joint laxity (0.19 to 0.21; P>0.05). When examined by gender, no statistically significant correlations (0.05 to 0.40; P>0.05) were found for either generalized laxity or instrumented ankle and knee joint laxity. CONCLUSIONS: These results imply that ankle and knee joint laxity are joint-specific and not generalizable.     

高山滑雪运动踝关节急性期损伤MRI表现

目的:探讨高山滑雪运动(AS)踝关节急性期损伤MRI特点。方法:搜集27例AS运动踝关节急性损伤患者(共29个踝关节损伤)作为实验组;随机选取30例普通外伤踝关节患者(共30个踝关节损伤)作为对照组。采用3.0T MRI和相控阵线圈进行踝关节扫描。由2名放射科主治医师评估膝关节骨、软骨、韧带、肌腱等损伤。结果:实验组多结构联合损伤29(100%)个;对照组多结构联合损伤24(80.00%)个。MRI显示实验组内踝、外踝、胫骨滑车、距骨、跟骨、舟骨、骰骨挫伤/骨折分别为14、12、12、17、15、13、14个,对照组分别为7、5、5、9、8、6、6个;实验组内侧胫距关节软骨、外侧胫骨关节软骨、距下关节软骨、距跟舟关节软骨、距骰关节软骨损伤分别为16、15、14、12、13个,对照组分别为8、6、7、5、5个;实验组三角韧带、距腓前韧带、距腓后韧带、跟腓韧带、下胫腓前韧带、下胫腓后韧带损伤分别为16、17、13、16、15、12个,对照组分别为8、9、6、9、7、5个;实验组拇长屈肌肌腱、趾长屈肌肌腱、胫骨后肌肌腱、腓骨长短肌肌腱、拇长伸肌肌腱,趾长伸肌肌腱、胫骨前肌肌腱损、跟腱损伤分别为14、15、14、14、14、13、14、15个,对照组分别为7、7、6、7、6、6、7、8个。两组损伤发生率差异具有统计学意义(P均<0.05)。实验组关节软骨损伤0、Ⅰ、Ⅱ、Ⅲ、Ⅳ级分别为75、33、16、11、10个,对照组分别为119、12、7、6、6个;实验组韧带损伤0、Ⅰ、Ⅱ、Ⅲ级分别为68、58、31、17个,对照组分别为124、31、13、12个;实验组肌腱损伤0、Ⅰ、Ⅱ、Ⅲ级分别为105、82、31、14个,对照组分别为171、45、15、9个。两组损伤程度差异具有统计学意义(P均<0.001)。实验组常见多个解剖部位、多发性骨挫伤/骨折,而对照组常见直接撞击部位的骨挫伤/骨折。实验组关节软骨常表现≥Ⅱ级损伤,而对照组软骨损伤常表现Ⅰ级损伤。实验组多表现为多条韧带联合损伤,以Ⅱ级损伤居多;对照组以单条韧带损伤为主,以Ⅰ级损表现居多。实验组常表现多条肌腱Ⅰ级损伤,对照组常表现单条Ⅰ级损伤。结论:滑雪运动踝关节损伤为骨髓、软骨、韧带及肌腱的联合损伤,正确认识滑雪运动踝关节急性期损伤的MRI表现,对早期诊断、踝关节功能恢复有重要意义。     

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 anterior inferior tibiofibular ligament and talar impingement: a cadaveric study

Impingement by the distal fascicle of the anterior inferior tibiofibular ligament (AITFL) is a relatively new entity among the known causes of anterolateral impingement syndromes of the ankle. This study investigated the anatomy of the anterior inferior tibiofibular ligament and its possible role in talar impingement in 47 ankles of 27 cadavers. The length, width, insertion point to the fibula and the interactions with talus were noted, as was the relationship of the fascicle and talus during different ankle movements before and after incision of the lateral ligaments. A distal fascicle of the AITFL was found in 39 of the 47 ankles (83%) and appeared as a single-complete ligament in the remaining 8 ankles (17%). The fascicle averaged 16.1+/-2.94 mm in length (range 10-21) and 4.2+/-1.00 mm in width (range, 3-7). The insertion point of the fascicle on the fibula averaged 10.3+/-2.27 mm (5-13) distal to the joint level. Contact between the ligament and the lateral dome of the talus was observed in 42 specimens (89.3%). Bending of the fascicle was observed in 8 of these 42 ankles with forced dorsiflexion. These 8 specimens were significantly wider and longer than the specimens without bending of the fascicle. Incision of the anterior talofibular ligament led to bending in dorsiflexion in additional 11 ankles. The total 19 fascicles with bending after incision of the anterior talofibular ligament were significantly longer and inserted more distally than the remaining 20 fascisles without bending. Manual traction simulating distraction during arthroscopic procedures relieved the contact. These findings show that the presence of the distal fascicle of the AITFL and its contact with the talus is a normal finding. However, it may become pathological due to anatomical variations and/or instability of the ankle resulting from torn lateral ligaments. When observed during an ankle arthroscopy, the surgeon should look for the criteria described in the present study to decide whether it is pathological and needs to be resected.     

In vivo kinematics of the knee after anterior cruciate ligament reconstruction: a clinical and functional evaluation

BACKGROUND: Recent follow-up studies have reported a high incidence of joint degeneration in patients with anterior cruciate ligament reconstruction. Abnormal kinematics after anterior cruciate ligament reconstruction have been thought to contribute to the degeneration. HYPOTHESIS: Anterior cruciate ligament reconstruction, which was designed to restore anterior knee laxity under anterior tibial loads, does not reproduce knee kinematics under in vivo physiological loading conditions. STUDY DESIGN: Controlled laboratory study. METHODS: Both knees of 7 patients with complete unilateral rupture of the anterior cruciate ligament were magnetic resonance imaged, and 3D models were constructed from these images. The anterior cruciate ligament of the injured knee was arthroscopically reconstructed using a bone-patellar tendon-bone autograft. Three months after surgery, the kinematics of the intact contralateral and reconstructed knees were measured using a dual-orthogonal fluoroscopic system while the subjects performed a single-legged weightbearing lunge. The anterior laxity of both knees was measured using a KT-1000 arthrometer. RESULTS: The anterior laxity of the reconstructed knee as measured with the arthrometer was similar to that of the intact contralateral knee. However, under weightbearing conditions, there was a statistically significant increase in anterior translation of the reconstructed knee compared with the intact knee at full extension (approximately 2.9 mm) and 15 degrees (approximately 2.2 mm) of flexion. In addition, there was a mean increase in external tibial rotation of the anterior cruciate ligament-reconstructed knee beyond 30 degrees of flexion (approximately 2 degrees at 30 degrees of flexion), although no statistical significance was detected. CONCLUSION: The data demonstrate that although anterior laxity was restored during KT-1000 arthrometer testing, anterior cruciate ligament reconstruction did not restore normal knee kinematics under weightbearing loading conditions. CLINICAL RELEVANCE: Future reconstruction techniques should aim to restore function of the knee under physiological loading conditions.     

Knee laxity modifications after ACL rupture and surgical intra- and extra-articular reconstructions: intra-operative measures in reconstructed and healthy knees

Purpose

Quantifying the effects of anterior cruciate ligament (ACL) deficiency on knee joint laxity is fundamental for understanding the outcomes of its reconstruction techniques. The general aim of this study was to determine intra-operatively the main modifications in knee laxity before and after standard isolated intra-articular and additional extra-articular anterolateral reinforcement. Our main hypothesis was that laxity abnormalities, particularly axial rotation, can still result from these ACL reconstruction techniques.

Methods

Thirty-two patients with primary ACL deficiency were analysed by a navigation system immediately before and after each of the two reconstructions. Laxity measurements in terms of knee translations and rotations were taken during the anteroposterior drawer test, with internal–external rotation at 20° and 90° of flexion, and varus–valgus and pivot-shift tests. All these laxity measures were also taken originally from the contralateral healthy knee.

Results

With respect to the contralateral healthy knee, in the ACL-deficient knee significantly increased laxity (expressed in %) was found in the medial compared with that of the lateral compartment, respectively, 115 and 68 % in the drawer test at 20° flexion, and 55 and 46 % at 90° flexion. In the medial compartment, a significant 35 % increment was also observed for the coupled tibial anteroposterior translation during axial knee rotation at 20° of flexion. After isolated intra-articular reconstruction, normal values of anteroposterior laxity were found restored in the pivot-shift and drawer tests in the lateral compartment, but not fully in the medial compartment. After the reinforcement, laxity in the medial compartment was also found restored in the axial rotation test at 20° flexion.

Conclusion

In ACL reconstruction, with respect to the contralateral knee, intra-articular plus additional anterolateral reinforcement procedures do not restore normal joint laxity. This combined procedure over-constrained the lateral compartment, while excessive laxity still persists at the medial one.

Level of evidence

III.

     

Excessive humeral external rotation results in increased shoulder laxity

BACKGROUND: The quantitative relationship between increased anterior shoulder laxity and increased humeral external rotation observed in throwers remains unclear. HYPOTHESIS: An elongated anterior capsule, especially the anterior band of the inferior glenohumeral ligament, produced by excessive humeral external rotation will result in increased anterior shoulder laxity and increased humeral external rotation. STUDY DESIGN: Controlled laboratory study. METHODS: Seven cadaveric shoulders were tested to measure the humeral rotational range of motion, glenohumeral translations, and length of the anterior band of the inferior glenohumeral ligament. Data were collected for the intact shoulders and after nondestructive stretching of 10%, 20%, and 30% beyond maximum humeral external rotation. RESULTS: Nondestructive excessive external rotational stretching resulted in a significant increase in superior (30%, 3.3 mm) and inferior (30%, 2.3 mm) length of the anterior band of the inferior glenohumeral ligament, external rotation (30%, 35 degrees), and anterior (30%, 2.4 mm), inferior (30%, 2.2 mm), and anterior-posterior (30%, 5.1 mm) translations. There were significant positive linear correlations between the length of the anterior band of the inferior glenohumeral ligament, external rotation, and anterior translation. CONCLUSIONS: Excessive humeral external rotation results in an elongation of the anterior band of the inferior glenohumeral ligament and an increase in anterior and inferior glenohumeral translations and humeral external rotation. CLINICAL RELEVANCE: Repetitive excessive humeral external rotation observed in throwers may be one of the biomechanical causes for increased shoulder laxity and increased humeral external rotation.