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.     

Diagnostic validity of alternative manual stress radiographic technique detecting subtalar instability with concomitant ankle instability

Purpose

To incorporate a diagnostic technique for measuring subtalar motion, namely “talar rotation”, into the manual supination-anterior drawer stress radiographs for evaluation of the severity of rotational instability, and to determine its clinical relevance.

Methods

Sixty-six patients with combined injuries of the anterior talofibular (ATFL) and calcaneofibular ligament (CFL) underwent three bilateral manual stress radiographs, and mean increments of anterior talar translation (mm), talar tilt (°), and talar rotation (%) in the injured ankle compared to the normal opposite side were measured with the technique. Intraobserver and interobserver reliability of each measure was assessed, and the difference in the degree of increments was compared according to the presence of additional cervical ligament insufficiency.

Results

Ankle stress radiographic intraobserver and interobserver agreement was ICC = 0.91 and 0.82 for talar rotation (%), ICC = 0.64 and 0.51 for anterior talar translation, and ICC = 0.78 and 0.71 for talar tilt angle, respectively. In group 2 including patients with combined injuries of the ATFL and CFL along with additional cervical ligament insufficiency, a significantly higher increment of talar rotation, mean 6.4 % (SD 3.4 %), was observed compared to that of talar rotation, mean 4.1 % (SD 2.7 %), in the other group (group 1) with an intact cervical ligament (p < 0.001).

Conclusions

A new comprehensive stress radiographic technique for diagnosis of chronic lateral ankle instability presented in this study might be a reliable and representable measurement tool to assess additional injury or instability of the subtalar joint.

Level of evidence

Prospective cohort study, Level II.

     

The improvement of postural control in patients with mechanical ankle instability after lateral ankle ligaments reconstruction

Purpose

Lateral ankle sprain is the most common injury. A previous study demonstrated that patients with mechanical ankle instability suffered deficits in postural control, indicating that structural damage of the lateral ankle ligaments may produce a balance deficit. The purpose of this study was to confirm that lateral ligaments reconstruction could improve postural control in patients with mechanical ankle instability.

Methods

A total of 15 patients were included in the study. Each patient had a history of an ankle sprain with persistent symptoms of ankle instability and a positive anterior drawer test and had been treated nonoperatively for at least 3 months. All patients were diagnosed with lateral ankle ligaments tear by ultrasonography and magnetic resonance imaging. They underwent arthroscopic debridement and open lateral ankle ligaments reconstruction with a modified Broström procedure. One day before and 6 months after the operation, all of the participants underwent single-limb postural sway tests. The anterior drawer test and the American Orthopedic Foot and Ankle Society scale score were used to evaluate the clinical results in these patients.

Results

At 6 months after the operation, with the patients’ eyes closed, there was significantly decreased postural sway in the anteroposterior direction, the circumferential area, and the total path length on the operated ankles compared with those measurements before the operation. With eyes open, however, no difference was found in postural sway before and after the operation.

Conclusions

Postural control was improved by reconstructing the lateral ligaments.

Level of evidence

IV.

     

Biomechanical stability of tape augmentation for anterior talofibular ligament (ATFL) repair compared to the native ATFL

Purpose

Current methods of anterior talofibular ligament (ATFL) reconstruction fail to restore the stability of the native ATFL. Therefore, augmented anatomic ATFL reconstruction gained popularity in patients with attenuated tissue and additional stress on the lateral ankle ligament complex. The aim of the present study was to evaluate the biomechanical stability of the InternalBrace^® (Arthrex Inc., Naples, FL, USA), a tape augmentation designed to augment the traditional Broström procedure.

Methods

Twelve (12) fresh-frozen human anatomic lower leg specimens were randomized into two groups: a native ATFL (ATFL) and a tape augmentation group (IB). Dual-energy X-ray absorptiometry (DEXA) scans were carried out to determine bone mineral density (BMD) of the specimens. The ligaments were stressed by internally rotating the tibia against the inverted fixated hindfoot. Torque at failure (Nm) and angle at failure (°) were recorded.

Results

The ATFL group failed at an angle of 33 ± 10°. In the IB group, construct failure occurred at an angle of 46 ± 16°. Failure torque reached 8.3 ± 4.5 Nm in the ATFL group, whereas the IB group achieved 11.2 ± 7.1 Nm. There was no correlation between angle at ATFL or IB construct failure or torque at failure, respectively, and BMD for both groups.

Conclusion

This study reveals that tape augmentation for ATFL reconstruction shows similar biomechanical stability compared to an intact native ATFL in terms of torque at failure and angle at failure. BMD did not influence the construct stability. Tape augmentation proved an enhanced initial stability in ATFL reconstruction which may allow for an accelerated rehabilitation process.

Level of evidence

II.

     

Endoscopic reconstruction of CFL and the ATFL with a gracilis graft: a cadaveric study

Purpose

The purpose of this study was to evaluate a step-by-step approach to endoscopic reconstruction of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL).

Methods

Fourteen lower extremity cadaveric specimens were used. Four standard portals were defined and used. A step-by-step approach using several anatomical landmarks was used to reconstruct the ATFL and CFL. The feasibility of visualising the anatomical landmarks and both ligaments and their footprints was assessed. Both ligaments were reconstructed using a gracilis graft fixed in bone tunnels. The lateral side of the ankle was completely exposed and dissected. The specimen was assessed for clinical stability of the reconstruction and damage to the surrounding anatomical structures. The distance between the centre of the tunnel and the anatomical insertions of the ligaments was measured. The distance between the portals and the nerves was measured.

Results

The step-by-step approach allowed a good visualisation of the entire course of the ATFL and CFL. An endoscopic reconstruction of both ligaments was performed, and good stability was obtained. The measurements revealed a good positioning of the reconstructed ligament insertions with a maximal error of 2 mm in most specimens. Anatomical dissection revealed no damage to the surrounding anatomical structures that were at risk. The average distance to the superficial peroneal nerve was 11.9 ± 5.3 mm (standard deviation), and the average distance to the sural nerve was 17.4 ± 3.2 mm (standard deviation). A safe zone was defined with regard to the surrounding nerves.

Conclusion

The described technique, which involves an anatomical endoscopic reconstruction of the ATFL and CFL, using a gracilis graft, is a viable option to treat lateral ankle instability. This technique is reproducible and safe with regard to the surrounding anatomical structures.

     

Assessment of the feasibility of arthroscopic visualization of the lateral ligament of the ankle: a cadaveric study

Purpose

An anatomical study was performed to assess the feasibility of arthroscopic visualization of the lateral ligaments of the ankle.

Methods

The fibular, talar and calcanear insertions of the anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) were identified by standard arthroscopy portals. After dissection of the ATFL and CFL, bone tunnels were created at the estimated centres of their footprints. Dissection was then performed to identify the footprints and their position in relation to bony landmarks. The distance from the real centre of the footprint to the corresponding tunnel entrance was measured.

Results

Fourteen fresh frozen ankles were included. The ATFL and CFL were identified in all cases. The centre of the fibular ATFL footprint was found to be 16.1 ± 3.5 mm from the tip of the fibula, and the talar footprint was 18.4 ± 2.8 mm from the apex of the lateral talar process. The centre of the fibular CFL footprint was 4.2 ± 0.8 mm from the tip of the fibula, and the calcaneal footprint was 18.4 ± 2.5 mm from the fibular process of the calcaneum. The fibular tunnel was 2.9 ± 3 mm proximally from the centre of the ATFL fibular footprint, the talar tunnel was 4.4 ± 3.2 mm proximally from the centre of the talar footprint, and the calcaneal tunnel was 3.3 ± 2.8 mm too anterior from the CFL calcaneal footprint. No iatrogenic lesions were noted.

Conclusion

Arthroscopic identification of the ATFL, CFL and their corresponding footprints can be considered safe and reliable. Tunnels entrances, in preparation for arthroscopic ligament reconstruction, are precisely positioned. Arthroscopic anatomical ligament reconstruction is a feasible option.

     

Dynamic balance deficits in individuals with chronic ankle instability compared to ankle sprain copers 1 year after a first-time lateral ankle sprain injury

Purpose

To quantify the dynamic balance deficits that characterise a group with chronic ankle instability compared to lateral ankle sprain copers and non-injured controls using kinematic and kinetic outcomes.

Methods

Forty-two participants with chronic ankle instability and twenty-eight lateral ankle sprain copers were initially recruited within 2 weeks of sustaining a first-time, acute lateral ankle sprain and required to attend our laboratory 1 year later to complete the current study protocol. An additional group of non-injured individuals were also recruited to act as a control group. All participants completed the anterior, posterior-lateral and posterior-medial reach directions of the star excursion balance test. Sagittal plane kinematics of the lower extremity and associated fractal dimension of the centre of pressure path were also acquired.

Results

Participants with chronic ankle instability displayed poorer performance in the anterior, posterior-medial and posterior-lateral reach directions compared with controls bilaterally, and in the posterior-lateral direction compared with lateral ankle sprain copers on their ‘involved’ limb only. These performance deficits in the posterior-lateral and posterior-medial directions were associated with reduced flexion and dorsiflexion displacements at the hip, knee and ankle at the point of maximum reach, and coincided with reduced complexity of the centre of pressure path.

Conclusion

In comparison with lateral ankle sprain copers and controls, participants with chronic ankle instability were characterised by dynamic balance deficits as measured using the SEBT. This was attested to reduced sagittal plane motions at the hip, knee and ankle joints, and reduced capacity of the stance limb to avail of its supporting base.

Level of evidence

III.

     

Kinematics and muscle activities of the lower limb during a side-cutting task in subjects with chronic ankle instability

Purpose

The purpose of the present study was to evaluate lower limb kinematics and muscular activities during walking, side-turning while walking, and side-cutting movement in athletes with chronic ankle instability and compare the results to those of athletes without chronic ankle instability.

Methods

Lower limb kinematics and muscular activities were evaluated in 10 athletes with chronic ankle instability and 10 healthy control athletes using a three-dimensional motion analysis system and surface electromyography during the 200-ms pre-initial contact (IC) and stance phases while walking, side-turning while walking, and side-cutting.

Results

During walking or side-turning while walking, there were no significant differences in kinematics or muscle activities between the subjects with and without chronic ankle instability. For the side-cutting task, however, ankle inversion angles during the 200-ms pre-IC and late stance phases [effect sizes (ESs) = 0.95–1.43], the hip flexion angle (ESs = 0.94–0.96) and muscular activities of the gastrocnemius medialis (ESs = 1.04–1.73) during the early stance phase were significantly greater in the athletes with chronic ankle instability than in the healthy control athletes.

Conclusions

Alterations of kinematics in athletes with chronic ankle instability were found not only at the ankle but also at hip joints during the side-cutting movement. These alterations were not detected during walking or side-turning while walking. The findings of the present study indicate that clinicians should take into account the motion of the hip joint during the side-cutting movement in persons with chronic ankle instability.

Level of evidence

III.

     

A matched pairs comparison of single- versus double-bundle anterior cruciate ligament reconstructions,clinical results and manual laxity testing

Purpose

To compare the subjective clinical results as well as manual anterior and rotational stability in patients treated with either single- (SB) or double-bundle (DB) anterior cruciate ligament (ACL) reconstructions.

Methods

Sixty-four patients who had undergone SB or DB hamstring ACL reconstruction with hamstrings were included in a retrospective matched pair analysis. At follow-up IKDC subjective, CKS, KOOS, CKS and a visual analogue satisfaction scale was assessed. A blinded surgeon examined the joint laxity and completed the objective IKDC. The KT-1000 was used to bilaterally test anterior tibial translation. Patients with confounding variables, which statistically influenced the clinical outcome (passive flexion and extension deficits, persistent quadriceps deficit, tibiofemoral osteoarthritis and non-repairable medial meniscus injury), were identified and excluded from the statistical analysis (n = 10).

Results

For all subjective scores, DB patients reported increased scores compared with SB patients. While consistently higher scores were demonstrated, statistical significance was only achieved for the IKDC subjective (P = 0.04) and VAS satisfaction (P = 0.02). Graded stability results of the Lachman, anterior drawer and pivot-shift tests were significantly higher in the DB group and KT-1000 side-to-side difference was significantly better for DB (P = 0.01).

Conclusion

DB ACL reconstruction appeared to more consistently result in significantly higher subjective outcome scores and manual tests of joint stability than SB ACL reconstruction. Besides the surgical technique, normal extension and quadriceps strength after surgery were identified to be an essential component in order to provide the patient with a successful outcome.

Level of evidence

II.

     

Mechanical functions of the three bundles consisting of the human anterior cruciate ligament

Purpose

The reconstruction technique to individually reconstruct multi-bundles of the anterior cruciate ligament (ACL) has been improved in the last decade. For further improvement of the technique, the present study was conducted to determine the force sharing among the three bundles (the medial and lateral bundles (AMM and AML) of the anteromedial (AM) bundle and the posterlateral (PL) bundle) of the human ACL in response to hyperextension, passive flexion–extension and anterior force to the knee.

Methods

Using a 6-DOF robotic system, the human cadaveric knee specimens were subjected to hyperextension, passive flexion–extension and anterior–posterior tests, while recording the 6-DOF motion and force/moment of the knees. The intact knee motions recorded during the tests were reproduced after sequential bundle transection to determine the bundle forces.

Results

The bundle forces were around 10 N at 5 N-m of hyperextension and remained less than 5 N during passive flexion–extension. In response to 100 N of anterior force, the AMM and PL bundle forces were slightly higher than the AML bundle force at full extension. The AMM bundle force remained at a high level up to 90° of flexion, with significant differences versus the AML bundle force at 15°, 30° and 60° of flexion and the PL bundle force at 90° of flexion.

Conclusion

The AMM bundle is the primary stabilizer to tibial anterior drawer through wide range of motion, while the AML bundle is the secondary stabilizer in deep flexion angles. The PL bundle is the crucial stabilizer to hyperextension as well as tibial anterior drawer at full extension.

Level of evidence

Prognostic study, Level II.

     

Sectioning the anterolateral ligament did not increase tibiofemoral translation or rotation in an ACL-deficient cadaveric model

Purpose

The anterolateral ligament (ALL) has been proposed as a possible extra-articular stabiliser of the knee. Injury to the ALL may result in residual instability following surgical reconstruction of a ruptured anterior cruciate ligament (ACL). Few studies have evaluated the biomechanical role of the ALL. The purpose of this study was to investigate whether sectioning the ALL would have an influence on tibiofemoral translation or rotation during the anterior drawer, Lachman, pivot shift, external rotation, and internal rotation tests in an ACL-deficient knee.

Methods

Only whole-body specimens having an ALL were included in this study. Lachman, anterior drawer, external rotation, and internal rotation tests were performed manually. Pivot shift test was done using a mechanised pivot shifter. The amount of tibiofemoral translation and rotation was recorded by a navigation system. Each specimen was tested in its native state, after sectioning the ACL, and after combined sectioning of the ACL and the ALL.

Results

In six out of 14 cadaveric knees, an ALL could be identified. The ACL-deficient knee had significantly more tibiofemoral translation and rotation compared to the native knee (P < 0.05). However, no changes in the magnitudes of translation or rotation were seen after subsequent sectioning of the ALL compared to the ACL-deficient knee (P > 0.05).

Conclusion

Adding an ALL lesion in an ACL-deficient knee did not increase tibiofemoral instability in this cadaveric model. It remains unclear whether injury to the ALL would result in substantial knee instability in the setting of ACL injury in vivo. Further research is warranted to fully elucidate the role of the ALL during knee kinematics and to determine in which scenarios ALL repair would be warranted. Understanding the function of the ALL may improve the current treatment strategies for ACL ruptures.

     

Single-leg drop landing movement strategies in participants with chronic ankle instability compared with lateral ankle sprain ‘copers’

Purpose

To compare the movement patterns and underlying energetics of individuals with chronic ankle instability (CAI) to ankle sprain ‘copers’ during a landing task.

Methods

Twenty-eight (age 23.2 ± 4.9 years; body mass 75.5 ± 13.9 kg; height 1.7 ± 0.1 m) participants with CAI and 42 (age 22.7 ± 1.7 years; body mass 73.4 ± 11.3 kg; height 1.7 ± 0.1 m) ankle sprain ‘copers’ were evaluated 1 year after incurring a first-time lateral ankle sprain injury. Kinematics and kinetics of the hip, knee and ankle joints from 200 ms pre-initial contact (IC) to 200 ms post-IC, in addition to the vertical component of the landing ground reaction force, were acquired during performance of a drop land task.

Results

The CAI group adopted a position of increased hip flexion during the landing descent on their involved limb. This coincided with a reduced post-IC flexor pattern at the hip and increased overall hip joint stiffness compared to copers (?0.01 ± 0.05 vs 0.02 ± 0.05°/Nm kg^?1, p = 0.03).

Conclusions

Individuals with CAI display alterations in hip joint kinematics and energetics during a unipodal landing task compared to LAS ‘copers’. These alterations may be responsible for the increased risk of injury experienced by individuals with CAI during landing manoeuvres. Thus, clinicians must recognise the potential for joints proximal to the affected ankle to contribute to impaired function following an acute lateral ankle sprain injury and to develop rehabilitation protocols accordingly.

Level of evidence

Level III.

     

Global rotation has high sensitivity in ACL lesions within stress MRI

Purpose

This study aims to objectively compare side-to-side differences of P-A laxity alone and coupled with rotatory laxity within magnetic resonance imaging, in patients with total anterior cruciate ligament (ACL) rupture.

Methods

This prospective study enrolled sixty-one patients with signs and symptoms of unilateral total anterior cruciate ligament rupture, which were referred to magnetic resonance evaluation with simultaneous instrumented laxity measurements. Sixteen of those patients were randomly selected to also have the contralateral healthy knee laxity profile tested. Images were acquired for the medial and lateral tibial plateaus without pressure, with postero-anterior translation, and postero-anterior translation coupled with maximum internal and external rotation, respectively.

Results

All parameters measured were significantly different between healthy and injured knees (P < 0.05), with exception of lateral plateau without stress. The difference between injured and healthy knees for medial and lateral tibial plateaus anterior displacement (P < 0.05) and rotation (P < 0.001) was statistically significant. It was found a significant correlation between the global rotation of the lateral tibial plateau (lateral plateau with internal + external rotation) with pivot-shift, and between the anterior global translation of both tibial plateaus (medial + lateral tibial plateau) with Lachman. The anterior global translation of both tibial plateaus was the most specific test with a cut-off point of 11.1 mm (93.8 %), and the global rotation of the lateral tibial plateau was the most sensitive test with a correspondent cut-off point of 15.1 mm (92.9 %).

Conclusion

Objective laxity quantification of ACL-injured knees showed increased sagittal laxity, and simultaneously in sagittal and transversal planes, when compared to their healthy contralateral knee. Moreover, when measuring instability from anterior cruciate ligament ruptures, the anterior global translation of both tibial plateaus and global rotation of the lateral tibial plateau add diagnostic specificity and sensitivity. This work strengthens the evidence that the anterior cruciate ligament plays an important biomechanical role in controlling the anterior translation, but also both internal and external rotation. The high sensitivity and specificity of this device in objectively identifying and measuring the multiplanar instability clearly guides stability restoration clinical procedures. Level of evidence Cross-sectional study, Level III.

     

Surface electromyography and plantar pressure during walking in young adults with chronic ankle instability

Purpose

Lateral ankle sprains are common and can manifest into chronic ankle instability (CAI) resulting in altered gait mechanics that may lead to subsequent ankle sprains. Our purpose was to simultaneously analyse muscle activation patterns and plantar pressure distribution during walking in young adults with and without CAI.

Methods

Seventeen CAI and 17 healthy subjects walked on a treadmill at 4.8 km/h. Plantar pressure measures (pressure–time integral, peak pressure, time to peak pressure, contact area, contact time) of the entire foot and nine specific foot regions and medial–lateral location of centre of pressure (COP) were measured. Surface electromyography (EMG) root mean square (RMS) amplitudes throughout the entire stride cycle and area under RMS curve for 100 ms pre-initial contact (IC) and 200 ms post-IC for anterior tibialis, peroneus longus, medial gastrocnemius, and gluteus medius were collected.

Results

The CAI group demonstrated a more lateral COP throughout the stance phase (P < 0.001 and Cohen’s d > 0.9 for all 10 comparisons) and significantly increased peak pressure (P = 0.025) and pressure–time integral (P = 0.049) under the lateral forefoot. The CAI group had lower anterior tibialis RMS areas (P < 0.001) and significantly higher peroneus longus, medial gastrocnemius, and gluteus medius RMS areas during 100 ms pre-IC (P < 0.003). The CAI group had higher gluteus medius sEMG amplitudes during the final 50 % of stance and first 25 % of swing (P < 0.05).

Conclusions

The CAI group had large lateral deviations of their COP location throughout the entire stance phase and increased gluteus medius muscle activation amplitude during late stance through early swing phase.

Level of evidence

III.

     

How to drill the talar tunnel in ATFL reconstruction?

Purpose

Reconstruction of the anterior talofibular ligament may be indicated in cases of residual instability after conservative treatment. Often, a bone tunnel is used for fixation in the talar bone. The purpose of this study is to evaluate possible routes for drilling the talar tunnel.

Methods

Virtual tunnels were generated in a 3D bone model, oriented towards the following external landmarks: the talar neck, the most anterior point of the medial malleolus (MM), the most distal point of the MM, the most medial point of the MM, and the most posterior point of the MM. The parameters analysed for tunnels with lengths of 20, 25, and 30 mm were the maximum distance inside the bone and the distance from the tunnel to the bone surface. A minimal safe distance (MSD) was calculated for a tunnel with a diameter of 5 mm.

Results

The shortest measured distance before arriving outside the talar bone was 16.7 mm. The longest distances were obtained in the tunnels oriented towards the talar neck (mean value of 36.6, SD 2.8) and towards the most posterior point of the MM (mean value of 35.8, SD 0.3). Only one tunnel, measuring 20 mm in depth and oriented towards the most posterior point of the MM, revealed no individual values below the MSD.

Conclusion

External landmarks are useful for drilling a talar tunnel during reconstruction of the anterior talofibular ligament. Only one tunnel, oriented towards the most posterior point of the MM, measuring 5 mm in diameter and with a maximum depth of 20 mm, was safe in all individuals. Surgeons should be aware of these limits when treating patients with ankle instability.

     

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.

     

Lower material stiffness in rupture-repaired Achilles tendon during walking: transmission-mode ultrasound for post-surgical tendon evaluation

Purpose

This cross-sectional study used transmission-mode ultrasound to evaluate dynamic tendon properties during walking in surgically repaired and contralateral Achilles tendon (AT), with a median (range) post-operative period of 22 (4–58) months. It was hypothesised that the axial transmission speed of ultrasound (TSOU) during walking would be slower, indicating lower material stiffness in repaired compared with contralateral AT.

Methods

Ten patients [median (range) age 47 (37–69) years; height 180 (170–189) cm; weight 93 (62–119) kg], who had undergone open surgical repair of the AT and were clinically recovered according to their treating clinicians, walked barefoot on a treadmill at self-selected speed (1.0 ± 0.2 m/s). Synchronous measures of TSOU, sagittal ankle motion, vertical ground reaction force (GRF), and spatiotemporal gait parameters were recorded during 20 s of steady-state walking. Paired t tests were used to evaluate potential between-limb differences in TSOU, GRF, ankle motion, and spatiotemporal gait parameters.

Results

TSOU was significantly lower (≈175 m/s) in the repaired than in the contralateral AT over the entire gait cycle (P < 0.05). Sagittal ankle motion was significantly greater (≈3°) in the repaired than in the contralateral limb (P = 0.036). There were no significant differences in GRF or spatiotemporal parameters between limbs.

Conclusions

Repaired AT was characterised by a lower TSOU, reflecting a lower material stiffness in the repaired tendon than in the contralateral tendon. A lower material stiffness may underpin greater ankle joint motion of the repaired limb during walking and long-term deficits in the muscle-tendon unit reported with AT repair. Treatment and rehabilitation approaches that focus on increasing the material stiffness of the repaired AT may be clinically beneficial. Transmission-mode ultrasound would seem useful for quantifying tendon properties post AT rupture repair and may have the potential to individually guide rehabilitation programmes, thereby aiding safer return to physical activity.

Level of evidence

II.

     

Comparison of T2 Relaxation Values in Subtalar Cartilage between Patients with Lateral Instability of the Ankle Joint and Healthy Volunteers

Purpose

To evaluate the difference between T2 relaxation values of the subtalar cartilage in lateral ankle instability patients and healthy volunteers.

Materials and Methods

This institutional review board-approved study included 27 preoperative magnetic resonance imaging (MRI) examinations of 26 patients who underwent Broström operations. Data of previously enrolled healthy volunteers (12 volunteers, 13 MRIs) were used as controls. Two radiologists independently measured T2 values in eight posterior subtalar joint cartilage compartments: central calcaneus anterior (CCA) and posterior (CCP), central talus anterior (CTA) and posterior (CTP), lateral calcaneus anterior (LCA) and posterior (LCP), and lateral talus anterior (LTA) and posterior (LTP). Patient and control values were compared using linear regression analysis. Inter- and intraobserver agreement was calculated.

Results

Mean T2 values were significantly higher in the patient group in all measurements of subtalar joint cartilage compartments (p < 0.05) except that in LTP (p = 0.085) measured by reviewer 1. Both inter- and intraobserver agreements were excellent.

Conclusions

The T2 relaxation values of the subtalar cartilage were significantly higher in lateral ankle instability patients compared with those of controls.

Key Points

? Subtalar cartilage T2 values are increased in patients with lateral ankle instability. ? This trend was demonstrated regardless of the presence of talar dome cartilage lesions. ? Inter-and intraobserver agreements were excellent (intraclass coefficient range, 0.765-0.951) in subtalar cartilage T2 mapping.

     

Magnetic resonance imaging characterization of individual ankle syndesmosis structures in asymptomatic and surgically treated cohorts

Purpose

Historically, syndesmosis injuries have been underdiagnosed. The purpose of this study was to characterize the 3.0-T MRI presentations of the distal tibiofibular syndesmosis and its individual structures in both asymptomatic and injured cohorts.

Methods

Ten age-matched asymptomatic volunteers were imaged to characterize the asymptomatic syndesmotic anatomy. A series of 21 consecutive patients with a pre-operative 3.0-T ankle MRI and subsequent arthroscopic evaluation for suspected syndesmotic injury were reviewed and analysed. Prospectively collected pre-operative MRI findings were correlated with arthroscopy to assess diagnostic accuracy [sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)].

Results

Pathology diagnosed on pre-operative MRI correlated strongly with arthroscopic findings. Syndesmotic ligament disruption was prospectively diagnosed on MRI with excellent sensitivity, specificity, PPV, NPV, and accuracy: anterior inferior tibiofibular ligament (87.5, 100, 100, 71.4, 90.5 %); posterior inferior tibiofibular ligament (N/A, 95.2, 0.0, 100, 95.2 %); and interosseous tibiofibular ligament (66.7, 86.7, 66.7, 86.7, 81.0 %).

Conclusions

Pre-operative 3.0-T MRI demonstrated excellent accuracy in the diagnosis of syndesmotic ligament tears and allowed for the visualization of relevant individual syndesmosis structures. Using a standard clinical ankle MRI protocol at 3.0-T, associated ligament injuries could be readily identified. Clinical implementation of optimal high-field MRI sequences in a standard clinical ankle MRI exam can aid in the diagnosis of syndesmotic injuries, augment pre-operative planning, and facilitate anatomic repair by providing additional details regarding the integrity of individual syndesmotic structures not discernible through physical examination and radiographic assessments.

Level of evidence

II.

     

Acute chondrocyte response to controlling joint instability in an osteoarthritis rat model

Objective

Osteoarthritis is a common consequence of anterior cruciate ligament (ACL) injury. Joint instability induced by ACL transection is involved in the chondrocyte response in the articular cartilage degeneration process. The aim of this study was to confirm the effect of controlling joint instability after ACL injury by investigating the chondrocyte reaction in the early osteoarthritic disease process.

Methods

For inducing different joint conditions (stability and instability), 15 Wistar rats were randomized into three groups: ACL transection with joint instability (ACL-T, n = 5), controlled abnormal joint movement with ACL transection (CAJM, n = 5), and control (n = 5). One week after surgery, all rats were euthanized and their knees removed. Histological analysis was performed on the knee cartilages, which involved evaluation of cell numbers and density.

Results

There were no significant differences in chondrocyte numbers among the three groups within each articular cartilage zone (surface, middle, and deep zones) nor between zones (P > 0.05). In contrast, the chondrocyte cell density area was significantly suppressed in the CAJM compared to the ACL-T group in each zone (surface zone, P = 0.019).

Conclusions

Early control of joint instability induced by ACL injury inhibited chondrocyte hypertrophy in articular cartilage. This result indicates that knee joint instability increases mechanical stress, and the controlling of these joint movements might provide a new treatment approach for the long-term prevention of osteoarthritis.