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.

     

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 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.

     

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.     

The role of the peroneal tendons in passive stabilisation of the ankle joint: an in vitro study

Purpose

Peroneal tendons are known as active stabilizer in acute ankle sprain while an intact ankle mortise and intact lateral ligaments are required for passive stability of the ankle joint. The goal of this study is to determine the peroneal tendons as passive stabilizer in case of lateral ligament instability.

Methods

Twelve (12) human lower leg cadaver specimens underwent a torsion simulation in the testing system, 858 Mini Bionix^® (MTS^® Systems Corporation, Eden Prairie, MN, USA) and a specially designed mounting platform for the specimens. The preset torsion between tibia and calcaneus was primarily set at 30° of internal rotation during plantar flexion and hindfoot inversion. The resisting torque around mechanical tibial axis was recorded which ensures stability in ankle sprain trauma. The first series of measurements were performed on healthy specimens and the following after transecting structures in following order: ATFL (anterior talofibular ligament) in combination with CFL (calcaneofibular ligament), followed by peroneus longus tendon and finally peroneus brevis tendon.

Results

The combined lateral ATFL and CFL instability shows a decrease of the resisting torque which ensures stability in ankle sprain trauma. Only a transection of PLT with existing lateral dual-ligament instability results in a significant decrease in torque (p < 0.0001).

Conclusion

The PLT has a substantial effect on passive stability at a present lateral ligament lesion in ankle sprain trauma. A deficiency in viscoelastic properties of the peroneus longus tendon must be considered in diagnostic and treatment for ankle instability.     

Quantitative evaluation of the viscoelastic properties of the ankle joint complex in patients suffering from ankle sprain by the anterior drawer test

Purpose

Biological tissues such as ligaments exhibit viscoelastic behaviours. Injury to the ligament may induce changes of these viscoelastic properties, and these changes could serve as biomarkers to detect the injury. In the present study, a novel instrument was developed to non-invasive quantify the viscoelastic properties of the ankle in vivo by the anterior drawer test. The purpose of the study was to investigate the reliability of the instrument and to compare the viscoelastic properties of the ankle between patients suffering from ankle sprain and controls.

Methods

Eight patients and eight controls participated in the present study. The reliability test was performed on three randomly chosen subjects. In patient and control test, both ankles of each subject were tested to evaluate the viscoelastic properties of the ankle. The viscosity index was defined for quantitatively evaluating the viscosity of the ankle. Greater viscosity index was associated with lower viscosity. Injured and uninjured ankles of patient and both ankles of controls were compared.

Results

The instrument exhibited excellent test–retest reliability (r > 0.9). Injured ankles exhibited significantly less viscosity than uninjured ankles, since injured ankles of patients had significantly higher viscosity index (8,148 ± 5,266) compared with uninjured ankles of patients (948 ± 617; p = 0.008) and controls (1,326 ± 613; p < 0.001).

Conclusions

The study revealed that the viscoelastic properties of the ankle can serve as sensitive and useful clinical biomarkers to differentiate between injured and uninjured ankles. The method may provide a clinical examination for objectively evaluating lateral ankle ligament injuries.     

The coronal alignment after medial unicompartmental knee arthroplasty can be predicted: usefulness of full-length valgus stress radiography for evaluating correctability

Purpose

We aimed to clarify whether the coronal alignment after medial unicompartmental knee arthroplasty (UKA) is predictable using preoperative full-length valgus stress radiography.

Methods

Thirty-seven consecutive patients with a mean age of 71.5 ± 7.0 years awaiting medial UKA were recruited. Full-length weight-bearing radiographs of the lower limbs were obtained pre- and postoperatively. Preoperative full-length valgus stress radiography in the supine position was also performed, and the transition of the hip-knee-ankle angle (HKAA) and the weight-bearing ratio were assessed. The tibia first cut technique was used, and the distal femur was cut parallel to the cutting surface of the proximal tibia during surgery.

Results

The mean postoperative HKAA was 2.0° ± 2.1° varus, and the mean weight-bearing ratio was 43.1 ± 7.7 %; each of these parameters demonstrated significantly strong correlations with the values on the preoperative valgus stress radiographs (p < 0.01), while the correlation between the postoperative alignment and the preoperative standing alignment without stress was moderate (p < 0.01). The postoperative alignment was slightly undercorrected compared to that observed on the valgus stress radiographs (p < 0.05), and no knees exhibited evident overcorrection compared to that on the valgus stress radiographs.

Conclusion

Preoperative valgus stress radiography is useful for evaluating the correctability of varus deformities and predicting the postoperative coronal alignment. For clinical relevance, performing preoperative valgus stress radiography would help to more precisely select patients and, when combined with the tibia first cut technique, aid in achieving the expected knee alignment and avoid severe undercorrection or overcorrection.

Level of evidence

Diagnostic study, Level II.     

An alternative injection technique for performing MR ankle arthrography: the lateral mortise approach

Objectives

This study evaluates whether the recently described lateral mortise (LM) approach to therapeutic ankle injections can also be used to inject the ankle prior to magnetic resonance arthrography (MRA) without impairing the evaluation of the anterior talofibular ligament (ATFL).

Materials and methods

An IRB-approved, retrospective review of ankle MRAs performed using the LM approach between April 2009 and April 2011 was conducted. The MRAs were independently evaluated by three musculoskeletal radiologists for: ATFL assessment (well assessed, limited or unable to assess), amount of fluid in the anterolateral soft tissues (none to large), and capsular distention (underdistended to overdistended). Patient age, gender, fluoroscopy time, injection location, degree of ankle arthritis, and ankle joint narrowing on radiographs were recorded. Statistical analysis was performed using exact binomial confidence limits.

Results

Fifteen MRAs were successfully performed on 13 patients (mean age: 27 years, 11 male, 2 female). Mean fluoroscopic time was 39 s (range 9–108) and mean volume injected was 7 mL (range 5–9 mL). The ATFL was well assessed on all MRAs. A moderate to large amount of fluid was noted in the anterolateral soft tissues on 5 out of 15 MRAs. No ankle joints were underdistended, but 3 out of 15 were overdistended.

Conclusion

Since the ATFL is inferior to the location used for the LM injection, the interpretation of the ankle MRA, specifically ATFL evaluation, was not compromised in any patient. Therefore, the LM approach can be used as an alternative to the anteromedial approach for ankle MRA without sacrificing diagnostic quality.     

Anatomic single- versus double-bundle ACL reconstruction: a meta-analysis

Purpose

To determine whether anatomic double-bundle anterior cruciate ligament (ACL) reconstruction compared to anatomic single-bundle ACL reconstruction more effectively restored antero–posterior (A–P) laxity, rotatory laxity and reduced frequency of graft rupture. Our hypothesis was that anatomic double-bundle ACL reconstruction results in superior rotational knee laxity and fewer graft ruptures due to its double-bundle tension pattern, compared with anatomic single-bundle ACL reconstruction.

Methods

An electronic search was performed using the PubMed, EMBASE and Cochrane Library databases. All therapeutic trials written in English reporting knee kinematic outcomes and graft rupture rates of primary anatomic double- versus single-bundle ACL reconstruction were included. Only clinical studies of levels I–II evidence were included. Data regarding kinematic tests were extracted and included pivot-shift test, Lachman test, anterior drawer test, KT-1000 measurements, A–P laxity measures using navigation and total internal–external (IRER) laxity measured using navigation, as well as graft failure frequency.

Results

A total of 7,154 studies were identified of which 15 papers (8 randomized controlled trials and 7 prospective cohort studies, n = 970 patients) met the eligibility criteria. Anatomic ACL double-bundle reconstruction demonstrated less anterior laxity using KT-1000 arthrometer with a standard mean difference (SMD) = 0.36 (95 % CI 0.214–0.513, p < 0.001) and less A–P laxity measured with navigation (SMD = 0.29 95 % CI 0.01–0.565, p = 0.042). Anatomic double-bundle ACL reconstruction did not lead to significant improvements in pivot-shift test, Lachman test, anterior drawer test, total IRER or graft failure rates compared to anatomic single-bundle ACL reconstruction.

Conclusion

Anatomic double-bundle ACL reconstruction is superior to anatomic single-bundle reconstruction in terms of restoration of knee kinematics, primarily A–P laxity. Whether these improvements of laxity result in long-term improvement of clinical meaningful outcomes remains uncertain.

Level of evidence

II.     

Three different cruciate-sacrificing TKA designs: minor intraoperative kinematic differences and negligible clinical differences

Purpose

The goal of this study was to compare three types of mobile-bearing posterior cruciate ligament (PCL)-sacrificing TKA. The hypothesis was that the three designs provide differences in flexion stability and femoral rollback and improved clinical score at 2-year follow-up.

Methods

Three groups of patients, divided according to implant design, were analysed retrospectively. All operations were guided by a non-image-based navigation system that recorded relative femoral and tibial positions in native and implanted knees during: passive range of motion and anterior drawer test at 90° flexion. WOMAC, KSS and SF36 scores were collected pre-operatively and at 2-year follow-up.

Results

There are no differences in kinematic or clinical performance of the three implants, except for the antero-posterior translation during stress test in flexion: only Cohort B had comparable pre- and post-operative laxity test values (p < 0.001). All three TKA designs allowed to maintain pre-operative tibial rotation pattern through all range of knee flexion. All clinical scores of the three patient cohorts were significantly improved post-operatively compared to the pre-operative values (p < 0.001). Moreover, we found no differences among post-operative results of the three designs.

Conclusion

Despite design variations, mobile-bearing PCL-sacrificing TKA reproduces femoral rollback and screw-home with little or no difference in clinical or functional scores at a follow-up of 2 years.

Level of evidence

III.     

Combined arthroscopic management of concurrent posterior and anterior ankle pathologies

Purpose

To determine the technical feasibility and preliminary clinical efficacy of performing simultaneous arthroscopic management in cases with combined posterior and anterior ankle pathologies utilizing previously described standard arthroscopic procedures within a single surgical sitting.

Methods

Nineteen consecutive patients with combined anterior and posterior ankle pathologies were included in the current study, after at least 6 months of failed conservative managements. Combined standard posterior and anterior ankle arthroscopy was performed in all patients within the same surgical session; first with the patient in the prone position, then with the patient turned onto the supine position to perform the anterior procedure.

Results

All patients were available for the follow-up; the median follow-up period was 33 months (range 22–61 months). No persistent neurological deficits or infections were recorded. The American Orthopedic Foot and Ankle Society Ankle and Hind foot Scale score significantly improved from 70.2 ± 15.2 points preoperatively to reach 93.0 ± 5.4 points at 1 year post-operatively (p < 0.001). Sixteen patients (84.2 %) returned to their previous activity levels.

Conclusions

Combined arthroscopic management of concurrent posterior and anterior ankle pathologies within the same surgical session is initially clinically encouraging; it allows for an earlier return to activities of daily living without a significantly added morbidity.

Level of evidence

Case series, Level 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.

     

Anterior fibrous bundle: a cause of residual pain and restrictive plantar flexion following ankle sprain

Purpose

To describe anterior fibrous bundle as an intra-articular residual disorder following ankle sprain.

Methods

Between January 1998 and January 2009, we performed arthroscopy on 10 patients (7 males, 3 females; median age, 25 years; age range, 17–43 years) who had the uncommon problem of anterior ankle pain accompanied by restriction of plantar flexion following an ankle sprain. Pre-operative magnetic resonance imaging revealed osteochondral lesions (OCLs) of the talar dome in 3 patients, but no other findings that could explain restricted plantar flexion. All patients underwent arthroscopy for investigation and treatment of the cause of symptoms, and the 3 patients with OCL underwent additional arthroscopic drilling. Outcome was measured using the American Orthopedic Foot and Ankle Society Ankle-Hindfoot Scale (AOFAS) score, Visual Analogue Scale (VAS) for pain and active plantar flexion angle.

Results

In all patients, an anterior fibrous bundle was confirmed under arthroscopic investigation as the cause of symptoms and was resected arthroscopically. Median AOFAS and VAS scores improved significantly from 65 (range 61–82) and 70 (range 50–85) pre-operatively to 95 (range 84–100) and 4 (range 0–15) at final follow-up, respectively (p < 0.001). In addition, median active plantar flexion angle improved significantly from 40° (range 35–40) pre-operatively to 55° (range 45–55), (p < 0.01).

Conclusions

An anterior fibrous bundle is one of the intra-articular residual disorders after ankle sprain that can cause restriction of plantar flexion.

Level of evidence

Therapeutic case series, Level IV.     

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.

     

The use of a mono-fluted reamer results in decreased enlargement of the tibial tunnel when using a transtibial ACL reconstruction technique

Purpose

To evaluate whether femoral tunnel preparation using a mono-fluted reamer rather than an acorn reamer would result in less tibial tunnel deformation when using a transtibial technique for anterior cruciate ligament reconstruction.

Methods

Tibial and femoral tunnel preparation was performed in four matched pairs of cadaveric knees. The tibial tunnel was drilled using a standard acorn reamer. The femoral tunnel was prepared using a transtibial technique with a mono-fluted reamer, and then, the same femoral tunnel was re-reamed using an acorn reamer. The anterior–posterior (AP) and medial–lateral (ML) dimensions of the tibial tunnel were recorded after each reamer. We then compared the measurements following the use of each reamer using a paired two-sample t test.

Results

There was a significantly larger degree of tibial tunnel deformation following femoral tunnel preparation with the acorn reamer when compared with the mono-fluted reamer. The initial tibial tunnel measured 10.5 and 10.1 mm in the AP and ML dimensions, respectively. The resultant AP diameter of the tibial tunnel after femoral reaming was 16.7 mm (p < 0.001) for the acorn reamer compared with 11.6 mm (p < 0.001) for the mono-fluted reamer. The ML diameters were 11.3 mm (p = 0.003) versus 10.2 mm (p = 0.07) for the acorn and mono-fluted reamer, respectively.

Conclusion

The use of a mono-fluted reamer for femoral tunnel preparation results in less tibial tunnel deformation during transtibial reaming.     

The dorsal pedis artery as a new distal landmark for extramedullary tibial alignment in total knee arthroplasty

Purpose

It is better to use multiple anatomical landmarks to reduce errors in component alignment in total knee arthroplasty. Therefore, it is worthwhile to find a new landmark that can be used as an addition to conventional ones. Herein, we assessed the dorsal pedis artery as a new distal landmark for extramedullary tibial alignment.

Methods

Fifty-two ankles in patients undergoing total knee arthroplasty and 10 ankles in normal controls were included. Color Doppler ultrasonography was used to locate the dorsal pedis artery at the level of the ankle joint. Conventional landmarks, including the tibialis anterior tendon, the extensor hallucis longus tendon, the extensor digitorum longus tendon, and the malleolar centre, were also located on ultrasound images. The distances between the ankle centre and each landmark were measured and compared.

Results

The dorsal pedis artery was absent in 2 patients and impalpable but visible with ultrasonography in other 2 patients. The dorsal pedis artery was located anatomically closest to the ankle centre in patients (0.4 ± 3.4 mm lateral). Statistical analysis showed that the dorsal pedis artery, the extensor hallucis longus tendon, and the malleolar centre were located significantly closer to the ankle centre comparing with the extensor digitorum longus tendon and the tibialis anterior tendon in both patients and controls (p < 0.001).

Conclusions

As long as the dorsal pedis artery exists, it can be used as an addition to the conventional landmarks in total knee arthroplasty. Using this new landmark will help reduce errors in coronal plane alignment of tibial component.

Level of evidence

II.     

Computer-assisted surgery improves rotational positioning of the femoral component but not the tibial component in total knee arthroplasty

Purpose

Computer-assisted surgery (CAS) may facilitate better positioning of total knee arthroplasty (TKA) along the coronal and lateral axes; however, there are doubts as to its usefulness in the rotational plane.

Methods

This is a prospective study of 95 TKAs comparing two groups: the CAS group and the standard equipment group. The series comprises 95 cases. A radiography of the lower limb and computer tomographies (CTs) of the femoral condylar region, the proximal end of the tibia and the ankle were performed to measure rotational angulation. A month after TKA surgery, the radiography and the CTs were repeated to analyze the position of the prosthetic components in the rotational plane.

Results

In the coronal axis, both CAS and mechanical technique improved femoro-tibial alignment, but when there are preexisting deformities ≥4°, CAS obtains better results. A strong correlation (R = 0.94, p = 0.001) was observed between the mean rotational axis measured with CT in the tibial plateau and that measured from the axis of the ankle. The mean initial femoral rotation of the complete series was 6.7° and 2.7° at 1-month follow-up (p < 0.001). In the standard instrumentation group, the femoral rotation went from 6.8° to 2.3°, whereas in the CAS group the femoral rotation went from 6.5° to 3.1° (p = 0.039), which is very close to the ideal 3° angle of external rotation. Tibial rotation changed by 5.28° for the entire patient population, but no differences were found when comparing CAS and standard instrumentation.

Conclusion

CAS improves frontal alignment in TKA, especially in the presence of preoperative deformities. In the femoral component, navigation most closely replicated the ideal 3° external rotation of the femoral component, but tibial rotation did not differ when comparing CAS to standard instrumentation.

Level of evidence

II.     

Anatomic medial patellofemoral ligament reconstruction using patellar suture anchor fixation for recurrent patellar instability

Purpose

The purpose of this study was to prospectively evaluate clinical and radiographic outcomes following anatomic medial patellofemoral ligament (MPFL) reconstruction using patellar suture anchor fixation for recurrent patellar instability.

Methods

Twenty patients (20 knees) were enrolled in this study. The median age was 21 years, and the median follow-up was 34.5 months. Reconstruction was performed using a hamstring autograft fixed with two suture anchors at native patellar site of the MPFL. No patient had undergone additional medial tibial tuberosity transfer. Clinical scores (Kujala, Lysholm, and Tegner score) and apprehension test were completed preoperatively and at the follow-up. Preoperative and follow-up radiographic assessments included modified Insall-Salvati ratio, congruence angle, and lateral patellofemoral angle.

Results

The preoperative Kujala and Lysholm scores were 52.6 ± 12.4 and 49.2 ± 10.7, and at follow-up visits, corresponding values were 90.9 ± 4.5 (p < 0.001) and 90.9 ± 5.2 (p < 0.001). Tegner score increased from 3.0 (range 1–4) to 5.0 (range 4–7) (p < 0.001). The apprehension test was positive in all patients preoperatively, but only positive in one patient at follow-up. All radiographic assessments were significantly improved; modified Insall-Salvati index (from 1.75 to 1.65) (p = 0.002), congruence angle (from 6.3° to ?7.0°) (p < 0.001), and lateral patellofemoral angle (from 2.1° to 4.9°) (p = 0.008). No patient experienced a patellar fracture or redislocation.

Conclusion

These results are comparable to those of bone tunnel techniques reported in the literature. This study shows that anatomic MPFL reconstruction using two suture anchors is a reliable treatment option.

Level of evidence

Case series with no comparison group, Level IV.     

Evaluation of anterior talofibular ligament injury with stress radiography, ultrasonography and MR imaging

Objective  

The purpose of this study was to clarify the efficacy of stress radiography (stress X-P), ultrasonography (US), and magnetic resonance (MR) imaging in the detection of the anterior talofibular ligament (ATFL) injury.