NOVEL Award 1996: 2nd prize Tenodeses do not fully restore ankle joint loading characteristics: a biomechanical in vitro investigation in the hind foot

In vivo evaluation of ankle kinematics and tibiotalar joint contact strains using digital volume correlation and 3 T clinical MRI

BACKGROUND

In vivo evaluation of ankle joint biomechanics is key to investigating the effect of injuries on the mechanics of the joint and evaluating the effectiveness of treatments. The objectives of this study were to 1) investigate the kinematics and contact strains of the ankle joint and 2) to investigate the correlation between the tibiotalar joint contact strains and the prevalence of osteochondral lesions of the talus distribution.

METHODS

Eight healthy human ankle joints were subjected to compressive load and 3 T MRIs were obtained before and after applying load. The MR images in combination with digital volume correlation enabled non-invasive measurement of ankle joint kinematics and tibiotalar joint contact strains in three dimensions.

FINDINGS

The total translation of the calcaneus was smaller (0.48 ± 0.15 mm, p < 0.05) than the distal tibia (0.93 ± 0.16 mm) and the talus (1.03 ± 0.26 mm). These movements can produce compressive and shear joint contact strains (approaching 9%), which can cause development of lesions on joints. 87.5% of peak tensile, compressive, and shear strains in the tibiotalar joint took place in the medial and lateral zones.

INTERPRETATION

The findings suggested that ankle bones translate independently from each other, and in some cases in opposite directions. These findings help explain the distribution of osteochondral lesions of the talus which have previously been observed to be in medial and lateral regions of the talar dome in 90% of cases. They also provide a reason for the central region of talar dome being less susceptible to developing osteochondral lesions.

The Superficial Peroneal Nerve Is at Risk during the "All Inside" Arthroscopic Broström Procedure: A Cadaveric Study

Background: The arthroscopic Broström procedure is a promising treatment for chronic ankle instability. However, little is known regarding the location of the intermediate superficial peroneal nerve at the level of the inferior extensor retinaculum; knowledge about this location is important for procedural safety. The purpose of this cadaveric study was to clarify the anatomical relationship between the intermediate superficial peroneal nerve and the sural nerve at the level of the inferior extensor retinaculum. Methods: Eleven dissections of cadaveric lower extremities were performed. The origin of the experimental three-dimensional axis was defined as the location of the anterolateral portal during ankle arthroscopy. The distances from the standard anterolateral portal to the inferior extensor retinaculum, sural nerve, and intermediate superficial peroneal nerve were measured using an electronic digital caliper. The location of inferior extensor retinaculum, the tract of sural nerve, and intermediate superficial peroneal nerve were checked using average and standard deviations. For the statistical analyses, data are presented as average ± standard deviation, and then they are reported as means and standard deviations. Fisher's exact test was used to identify statistically significant differences. Results: At the level of the inferior extensor retinaculum, the mean distances from the anterolateral portal to the proximal and distal intermediate superficial peroneal nerve were 15.9 ± 4.1 (range, 11.3-23.0) mm and 30.1 ± 5.5 (range, 20.8-37.9) mm, respectively. The mean distances from the anterolateral portal to the proximal and distal sural nerve were 47.6 ± 5.7 (range, 37.4-57.2) mm and 47.2 ± 4.1 (range, 41.0-51.8) mm), respectively. Conclusions: During the arthroscopic Broström procedure, the intermediate superficial peroneal nerve may be damaged by the anterolateral portal; the proximal and distal parts of the intermediate superficial peroneal nerve were located within 15.9 and 30.1 mm, respectively, at the level of the inferior extensor retinaculum in cadavers. These areas should be considered danger zones during the arthroscopic Broström procedure.

Presurgical Perspective and Postsurgical Evaluation of Instability and Microinstability Secondary to Ankle Ligaments Injury

Injuries of the ankle ligaments complexes are very common, and ∼ 20 to 40% of patients can develop chronic ankle instability (CAI). Current concepts in CAI allow a better understanding of the ankle biomechanics needed to repair it. The surgical treatment of CAI has evolved in the last decade, and ankle arthroscopy has become an essential tool in the treatment of instability with promising results. We review the different surgical techniques to treat CAI, both those frequently used and the new approaches, as well as the normal postsurgical appearance of ankle ligaments repair and the most common complications.

Ankle Instability

Ankle sprains are a common injury among physically active populations and occur with an incidence of around 2.15 per 1000 person-years. This article discusses various surgical procedures used to treat chronic lateral ankle instability, including direct ligament repair, anatomic reconstruction, and nonanatomic reconstruction. We focus our discussion on the most common and challenging complications of ankle stabilization, both in our experience and as supported by the existing literature, including recurrent instability, superficial peroneal nerve injury, and unaddressed pathology that continues to cause symptoms and limit function. We offer possible methods to manage these conditions as well as available outcome data.

[The periosteal flap augmentation technique in chronic lateral ankle instability]

OBJECTIVE

Anatomic repair of the lateral ligament complex of the ankle joint and augmentation with an autologous pedicled periosteal flap of the distal fibula following identification and concomitant treatment of intra-articular pathologies.

INDICATIONS

Symptomatic chronic mechanical lateral ankle instability. As a modular step in the treatment of osteochondral lesions in conjunction with lateral ankle instability.

CONTRAINDICATIONS

Higher degree osteoarthritis of the ankle joint (>Kellgren/Lawrence 2 and 4 or Outerbridge 3 and 4) and/or hindfoot deformity; mechanical incompetence of both the fibulotalar anterior ligament and the fibulocalcaneal ligament preventing anatomical reinsertion; general risk factors.

SURGICAL TECHNIQUE

Diagnostic arthroscopy for identification and treatment of intraarticular pathologies; verification and grading of ligamentous instability (medial, lateral, combined). Open exposure of the distal fibula and the ruptured components of the lateral ankle ligament complex. Anatomic reinsertion of the original ligaments and assessment of their mechanical competence. Apart from the situation in the juvenile patient with a thick periosteal layer a doubled and pedicled periosteal strip of the distal fibular periosteum will suffice for the augmentation in one ligamentous component, only. Fixation in the talus or calcaneus is achieved via suture anchors, screws with a washer or transosseous fixation via interference screw.

POSTOPERATIVE MANAGEMENT

Postoperative immobilization in a lower leg split cast or a splint until wound healing (5-8 days), mobilization in a walker or an ankle orthosis with consecutive full weight-bearing for further 4-5 weeks. Proprioceptive and pronator muscle training, optionally insole or lateral wedge at the shoe sole for 6 months postoperatively. Avoidance of contact sports for 4-6 months.

RESULTS

Several studies have reported reliable restoration of ligamentous ankle stability with overall success rates >90% and good to excellent total results in >90% of patients with limited minor complications. In view of the heterogeneous data from previous studies, some recent studies have demonstrated that the outcome after periosteal augmentation is comparable to that after techniques employing free tendon graft for anatomic restoration of ligamentous ankle stability. The technique has been applied successfully in cases of poor mechanical properties of the formerly ruptured ligaments and in patients with a high functional demand.

Surgical Treatment of Chronic Lateral Ankle Instability Using an Inferior Extensor Retinaculum Flap: A Retrospective Study

Chronic lateral ankle instability causes significant problems with physical activity. The purpose of the present study was to evaluate the results of ligamentous retensioning combined with reinforcement using an extensor retinaculum flap. A consecutive series of 38 patients were included with a minimum follow-up duration of 2 years. The functional results were assessed using the Karlsson and American Orthopaedic Foot and Ankle Society scale scores. The pre- and postoperative radiologic assessment was performed using stress radiographs to measure varus tilt and anterior drawer tests. All 38 patients were followed up for 2.5 to 7.2 years, and 35 patients were satisfied. The American Orthopaedic Foot and Ankle Society scale score had improved significantly from 57 (range 20 to 70) points preoperatively to 95 (range 80 to 100) points postoperatively (p < .0001), and 35 patients believed their ankle was more stable after surgery. The patients had returned to their previous sports activities an average of 4.7 (range 2 to 12) months after surgery. On the stress radiographs, the mean talar tilt angle had improved significantly from 15.2° (range 6° to 26°) preoperatively to 3.8° (range 1° to 8°) at the final follow-up visit (p < .001), and the mean anterior talar had improved significantly from 13.2 (range 8 to 18) mm preoperatively to 4 (range 4 to 7) mm at the final follow-up visit (p < .002). Regarding the prognostic factors, a link was found between the functional result and residual radiologic laxity measured on the stress radiographs. Reconstruction of the lateral ligaments for chronic ankle instability combining capsuloligamentous retensioning and reinforcement with an extensor retinaculum flap resulted in successful outcomes, excellent ankle stability, and preservation of ankle joint mobility. This technique addressed both lateral ankle and subtalar instability by developing an extraarticular interosseous ligament.

Subtalar Joint Biomechanics: From Normal to Pathologic

Subtalar joint biomechanics are primarily driven by the shape of the articulations with contributions from the surrounding soft tissues. The joint motion occurs about a single axis oriented medially and superiorly. Joint contact forces change during different stages of gait and are affected by hindfoot alignment and traumatic alterations to their normal anatomy. A valgus subtalar joint axis is likely a contributing, and perhaps primary, risk factor for progression to adult acquired flat foot. The subtalar joint axis also contributes to the clinical picture of a cavus foot and a special subset of patients with dynamic varus.

[Lateral ligament injuries]

Due to the frequency and potentially complicated course distortion of the upper angle joint represents an important entity in the orthopedic patient clientele. The initial diagnosis includes a detailed anamnesis of the injury mechanism and an accurate clinical examination. To exclude bony, ligamentous and chondral lesions, besides basic diagnostics consisting of X‑rays and ultrasound, magnetic resonance imaging (MRI) is considered the most important tool. Lateral ankle ligament injuries are generally treated conservatively. After a short period consisting of immobilization of the affected ankle, early functional therapy with semi-rigid orthoses and proprioceptive exercises should be performed. If conservative therapy fails and thus chronic instability develops the indications for operative treatment are given. Meanwhile, surgical techniques have been established with satisfactory results. Inadequate rehabilitation could be identified as a major risk factor for re-injury, therefore phase-adapted aftercare has gained significant importance.

Surgical Procedures for Chronic Lateral Ankle Instability

Surgical procedures for managing chronic lateral ankle instability include anatomic direct repair, anatomic reconstruction with an autograft or allograft, and arthroscopic repair. Open direct repair is commonly used for patients with sufficient ligament quality. Reconstruction incorporating either an autograft or an allograft is another promising option in the short term, although the longevity of this procedure remains unclear. Use of an allograft avoids donor site morbidity, but it comes with inherent risks. Arthroscopic repair of chronic lateral ankle instability can provide good to excellent short- and long-term clinical outcomes, but the evidence supporting this technique is limited. Deterioration of the ankle joint after surgery is also a concern. Studies are needed on not only treating ligament insufficiency but also on reducing the risk of ankle joint deterioration.

Foot-ankle simulators: A tool to advance biomechanical understanding of a complex anatomical structure

In vitro gait simulations have been available to researchers for more than two decades and have become an invaluable tool for understanding fundamental foot-ankle biomechanics. This has been realised through several incremental technological and methodological developments, such as the actuation of muscle tendons, the increase in controlled degrees of freedom and the use of advanced control schemes. Furthermore, in vitro experimentation enabled performing highly repeatable and controllable simulations of gait during simultaneous measurement of several biomechanical signals (e.g. bone kinematics, intra-articular pressure distribution, bone strain). Such signals cannot always be captured in detail using in vivo techniques, and the importance of in vitro experimentation is therefore highlighted. The information provided by in vitro gait simulations enabled researchers to answer numerous clinical questions related to pathology, injury and surgery. In this article, first an overview of the developments in design and methodology of the various foot-ankle simulators is presented. Furthermore, an overview of the conducted studies is outlined and an example of a study aiming at understanding the differences in kinematics of the hindfoot, ankle and subtalar joints after total ankle arthroplasty is presented. Finally, the limitations and future perspectives of in vitro experimentation and in particular of foot-ankle gait simulators are discussed. It is expected that the biofidelic nature of the controllers will be improved in order to make them more subject-specific and to link foot motion to the simulated behaviour of the entire missing body, providing additional information for understanding the complex anatomical structure of the foot.

In Vivo Talocrural Joint Contact Mechanics With Functional Ankle Instability

BACKGROUND

Functional ankle instability (FAI) may involve abnormal kinematics and contact mechanics during ankle internal rotation. Understanding of these abnormalities is important to prevent secondary problems in patients with FAI. However, there are no in vivo studies that have investigated talocrural joint contact mechanics during weightbearing ankle internal rotation. The objective of this study to determine talocrural contact mechanics during weightbearing ankle internal rotation in patients with FAI.

METHODS

Twelve male subjects with unilateral FAI (age range, 18-26 years) were enrolled. Computed tomography and fluoroscopic imaging of both lower extremities were obtained during weightbearing passive ankle joint complex rotation. Three-dimensional bone models created from the computed tomographic images were matched to the fluoroscopic images to compute 6 degrees of freedom for talocrural joint kinematics. The closest contact area in the talocrural joint in ankle neutral rotation and maximum internal rotation during either dorsiflexion or plantar flexion was determined using geometric bone models and talocrural joint kinematics data.

RESULTS

The closest contact area in the talus shifted anteromedially during ankle dorsiflexion-internal rotation, whereas it shifted posteromedially during ankle plantar flexion-internal rotation. The closest contact area in FAI joints was significantly more medial than that in healthy joints during maximum ankle internal rotation and was associated with excessive talocrural internal rotation or inversion.

DISCUSSION

This study demonstrated abnormal talocrural kinematics and contact mechanics in FAI subjects. Such abnormal kinematics may contribute to abnormal contact mechanics and may increase cartilage stress in FAI joints.

LEVEL OF EVIDENCE

Therapeutic, Level IV: cross-sectional case-control study.

Efficacy and Safety of Split Peroneal Tendon Lateral Ankle Stabilization

Chronic lateral ankle instability is a common condition. Split peroneal tendon lateral ankle stabilization, a modification of the Chrisman-Snook procedure, is biomechanically stable and often used for severe and/or recurrent chronic lateral ankle instability. The purpose of the present study was to evaluate the efficacy and safety of this technique. Specifically, the midterm recurrence of instability and postoperative complications, such as stiffness, neurologic pain, and wound healing complications, were evaluated. We evaluated 30 consecutive procedures with a minimal follow-up period of 1 year. The mean follow-up period was 25 ± 13 (median 19, range 13 to 62) months. Five patients (17%) developed recurrent ankle instability, of whom 4 underwent revision surgery. One superficial infection and two wound disruptions developed. Two patients experienced stiffness and eight (27%) surgically induced neurologic complaints, such as sural neuritis. Finally, 2 patients developed complex regional pain syndrome.

Anatomic lateral ligament reconstruction in the ankle: a hybrid technique in the athletic population

BACKGROUND

Anatomic and checkrein tenodesis reconstruction techniques have been described as a means of treatment for chronic lateral ligament instability in the ankle. The current article describes a hybrid procedure using the most advantageous concepts of both techniques for use when insufficient normal ligament remains to fashion a direct repair of the anterior talofibular ligament (ATFL).

PURPOSE

The authors report the results at a minimum 1-year follow-up of 57 patients who underwent a hybrid anatomic lateral ligament reconstruction technique in the ankle.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fifty-seven patients underwent a hybrid anatomic lateral ligament reconstruction procedure under the care of the senior author. All patients were assessed preoperatively and postoperatively using the Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) outcome score. The mean patient age at the time of surgery was 28 years (range, 17-65 years), including 39 male and 18 female patients. The mean follow-up time was 32 months (range, 12-47 months).

RESULTS

The FAOS improved from 58 points preoperatively to 89 points postoperatively (P < .01). The SF-12 score improved from 48 points before surgery to 80 points at final follow-up (P < .01). All patients achieved mechanical stability at final clinical follow-up; 7 patients (12%) demonstrated functional instability. Functional instability was found to significantly influence not returning to sport at the previous level.

CONCLUSION

This hybrid anatomic lateral ligament reconstruction technique using a peroneus longus autograft to substitute the native ATFL provides an alternative to anatomic reconstruction when direct repair is not possible.

The effect of modified Broström-Gould repair for lateral ankle instability on in vivo tibiotalar kinematics

BACKGROUND

Lateral ankle instability leads to an increased risk of tibiotalar joint osteoarthritis. Previous studies have found abnormal tibiotalar joint motions with lateral ankle instability that may contribute to this increased incidence of osteoarthritis, including increased anterior translation and internal rotation of the talus under weightbearing loading. Surgical repairs for lateral ankle instability have shown good clinical results, but the effects of repair on in vivo ankle motion are not well understood.

HYPOTHESIS

The modified Broström-Gould lateral ligament reconstruction decreases anterior translation and internal rotation of the talus under in vivo weightbearing loading conditions.

STUDY DESIGN

Controlled laboratory study.

METHODS

Seven patients underwent modified Broström-Gould repair for unilateral lateral ankle instability. Ankle joint kinematics as a function of increasing body weight was studied with magnetic resonance imaging and biplanar fluoroscopy. Tibiotalar kinematics was measured in unstable ankles preoperatively and postoperatively at a mean follow-up of 12 months as well as in the uninjured contralateral ankles of the same patients.

RESULTS

Surgical repair resulted in statistically significant decreases (expressed as mean ± standard error of the mean) in anterior translation of the talus (0.9 ± 0.3 mm; P = .018) at 100% body weight and internal rotation of the talus at 75% (2.6° ± 0.8°; P = .019) and 100% (2.7° ± 0.8°; P = .013) body weight compared with ankle kinematics measured before repair. No statistically significant differences were detected between repaired ankles and contralateral normal ankles.

CONCLUSION

The modified Broström-Gould repair improved the abnormal joint motion observed in patients with lateral ankle instability, decreasing anterior translation and internal rotation of the talus.

CLINICAL RELEVANCE

Altered kinematics may contribute to the tibiotalar joint degeneration that occurs with chronic lateral ankle instability. The findings of the current study support the efficacy of this repair in improving the abnormal ankle motion observed in these patients.

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 < 0.05), and median AOFAS score improved from 63 (41-84) to 91 (81-100) preoperatively to final follow-up (P < 0.05). Median Karlsson-Peterson score also significantly improved from 55 (32-77) to 80 (59-100) (P < 0.05), whereas talar tilt decreased from 17.8° (10.0°-25.5°) to 6.7° (0.3°-13.0°) and the mean anterior drawer test decreased from 10.0 mm (0.6-19.4) to 4.5 mm (0.2-8.7) (P < 0.05). Eighty-eight percent (21/24) were satisfied with surgery. No complication, such as subtalar stiffness or recurrent instability, was encountered.

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.

Autologous split peroneus longus lateral ankle stabilization

Lateral ankle instability is a common clinical entity, and a variety of surgical procedures are available for stabilization after conservative management fails. Herein the authors reviewed outcomes after performing autologous split peroneus longus lateral ankle stabilization, using a previously described surgical technique to anatomically recreate the anterior talofibular and calcaneofibular ligaments. Twenty-five consecutive patients from 2 surgeons' practices underwent reconstruction between March 2007 and January 2011 with a minimum follow-up of 12 (range 12 to 51) months (mean 29.5 months). Follow-up interviews demonstrated 92.0% good or excellent outcomes with only 8.0% rating the outcome as fair and none as poor; 92.0% had no recurrent sprains or difficulty going up or down hills; 88.0% related no difficulty with uneven ground. The authors conclude that the autologous split peroneus longus lateral ankle stabilization results in a stable ankle with a low rate of complications and high patient satisfaction.

Arthroscopic four-step treatment for chronic ankle instability

BACKGROUND

Chronic lateral ankle instability is a condition of perception of giving way and persistent pain usually following multiple ankle sprains. Open reconstructive procedures carry the disadvantages of subtalar joint stiffness and potential morbidity at the harvesting site. Recently, arthroscopic treatment of chronic lateral ankle instability has been proposed in order to minimize invasiveness, reduce operating time, and allow a faster rehabilitation period. The purpose of our paper was to assess the outcomes in terms of postoperative recovery and return to sport following arthroscopic reconstruction of lateral ankle instability.

METHODS

Ninety patients with chronic lateral ankle instability were treated at our Department from 2004 to 2009. Mean age was 32.4 (range, 17 to 56) years. All patients underwent a four-step operative procedure, including: synovectomy, debridement of ATFL lesion borders, capsular shrinkage, and 21-day immobilization and nonweightbearing.

RESULTS

Followup examination at an average of 4~years after surgery showed significant improvement of mean AOFAS scale (preoperative, 63.5; postoperative, 92.3; p < 0.001) and average Karlsson score (preoperative, 61.8; postoperative, 88.4; p < 0.001). Mean Tegner rating changed from 3.6 preoperatively to 4.9 at followup (p < 0.001). Articular stability as assessed by Sefton scale significantly improved from a preoperative value of 4.0 to 1.8 (p < 0.001). Most patients (96.6%) rated the success of their surgery as good to excellent.

CONCLUSION

Based on our results, we propose arthroscopic treatment as a suitable option for moderate chronic ankle joint laxity in patients with a complete ATFL lesion.

Anatomical reconstruction of the lateral ligaments using Gracillis tendon in chronic ankle instability; a new technique

BACKGROUND

Many surgical technique have been described to assess the outcome of anatomical reconstruction of the lateral ligaments using Gracillis tendon. This technique aims to restore the stability of the ankle by reconstruction of the talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) using the Gracillis tendon.

METHODS

From January 2004 to February 2008; inclusive, 16 patients; 11 male and 5 female, underwent an anatomic reconstruction of the lateral ankle ligament for chronic ankle instability. Their ages ranged from 18 to 29 giving a mean age of 25 years. Patients were then subjected to radiologic and clinical assessments for a period of at least 33.5 months. For pain scoring the Americans Orthopaedic Foot and Ankle Society (AOFAS) scores were used; whilst subjective symptom was evaluated using the Olerud and Molander ankle scoring system.

RESULTS

All patients returned for the final evaluation and subjective excellent or good results were recorded on self-assessment, pain scores, AOFAS and Karissons scores. Additionally Olerud and Molander ankle scoring was also done. During the final follow-up, the mean post-operative AOFAS score was 96 (range 80-100), the Visual analog score was 6 (range 0-4), Karissons score was 94.7 (range 80-100) and last but not least Olerud and Molander score was 87.5 (range 70-100). It was noted that the ankle range of motion was not affected by lateral ankle reconstruction. The talar tilt was reduced from a mean of 12-4° (p<0.0001) and the anterior drawer was reduced from a mean of 11-4mm (p<0.001) by the ankle ligament reconstruction.

CONCLUSION

Anatomical reconstruction of the lateral ligaments of chronic ankle instability using Gracillis tendon graft resulted in successful results, excellent ankle stability, significant reduction in pain and negligible loss of ankle and hind foot motion.

In vivo cartilage contact strains in patients with lateral ankle instability

Damage to the anterior talofibular ligament (ATFL) and cacaneofibular ligament (CFL) during an ankle sprain may be linked to the development of osteoarthritis. Although altered tibiotalar kinematics have been demonstrated, the effects of lateral ankle instability (LAI) on in vivo cartilage strains have not been described. We hypothesized that peak cartilage strains increase, and the location is shifted in patients with ATFL injuries. We used 3-D MRI models and biplanar fluoroscopy to evaluate in vivo cartilage contact strains in seven patients with unilateral LAI. Subjects had chronic unilateral ATFL injury or combined ATFL and CFL injury, and were evaluated with increasing load while stepping onto a force plate. Peak cartilage strain and the location of the peak strain were measured using the contralateral normal ankle as a control. Ankles with LAI demonstrated significantly increased peak strain when compared with ATFL-intact controls. For example, at 100% body weight, peak strain was 29+/-8% on the injured side compared to 21+/-5% on the intact side. The position of peak strain on the injured ankle also showed significant anterior translation and medial translation. At 100% body weight, the location of peak strain in the injured ankle translated anteriorly by 15.5+/-7.1mm and medially by 12.9+/-4.3mm relative to the intact ankle. These changes correspond to the region of clinically observed osteoarthritis. Chronic LAI, therefore, may contribute to the development of tibiotalar cartilage degeneration due to altered cartilage strains.

Modified Chrisman-Snook repair for the treatment of chronic ankle ligamentous instability in children and adolescents

PURPOSE

Chronic ankle ligamentous instability is not uncommonly encountered in children and adolescents. A number of operative procedures have been developed and described in the literature, including variations on the original Chrisman-Snook (CS) repair. The purpose of this study is to describe a modification of the CS repair and report the outcomes of this surgery for the treatment of chronic ankle ligamentous instability in children and adolescents.

METHODS

A retrospective review was conducted of 100 consecutive surgeries in 66 children performed by a single surgeon who modified the CS repair using a split peroneus brevis tendon to reinforce the anterior talofibular and calcaneofibular ligaments in chronic ligamentously lax patients. All charts were reviewed for complications. Fifty-three cases had at least a 2-year follow-up and were evaluated for the following outcomes: return to activity, ligamentous laxity, pain, and subsequent sprains.

RESULTS

Of the 100 surgeries performed, no patient required repeat ligamentous repair. There were no deep wound infections. There were 10 cases of minor wound healing problems and two cases of temporary nerve dysfunction, one of which resolved without surgical intervention and the other is resolving with no plans for surgical intervention. There were two cases of sural nerve branch entrapment which required subsequent surgery due to neuroma formation. Of the 53 cases with at least a 2-year follow-up, the following outcomes were obtained: all patients returned to full activities of their choice; all but one case maintained ≤45° of ankle inversion postoperatively; all patients were pain free or had only occasional discomfort; and 23% of the ankles experienced subsequent minor sprains, but all were minor and resolved without consequence.

CONCLUSIONS

A modification of the CS repair where the split peroneus brevis tendon is used to create ankle stability has been routinely successful in 100 consecutive cases of chronic ligamentous instability in children and adolescents with very few complications.

Lateral ligament repair and reconstruction restore neither contact mechanics of the ankle joint nor motion patterns of the hindfoot

BACKGROUND

Ankle sprains may damage both the lateral ligaments of the hindfoot and the osteochondral tissue of the ankle joint. When nonoperative treatment fails, operative approaches are indicated to restore both native motion patterns at the hindfoot and ankle joint contact mechanics. The goal of the present study was to determine the effect of lateral ligament injury, repair, and reconstruction on ankle joint contact mechanics and hindfoot motion patterns.

METHODS

Eight cadaveric specimens were tested with use of robotic technology to apply combined compressive (200-N) and inversion (4.5-Nm) loads to the hindfoot at 0° and 20° of plantar flexion. Contact mechanics at the ankle joint were simultaneously measured. A repeated-measures experiment was designed with use of the intact condition as control, with the other conditions including sectioned anterior talofibular and calcaneofibular ligaments, the Broström and Broström-Gould repairs, and graft reconstruction.

RESULTS

Ligament sectioning decreased contact area and caused a medial and anterior shift in the center of pressure with inversion loads relative to those with the intact condition. There were no significant differences in inversion or coupled axial rotation with inversion between the Broström repair and the intact condition; however, medial translation of the center of pressure remained elevated after the Broström repair relative to the intact condition. The Gould modification of the Broström procedure provided additional support to the hindfoot relative to the Broström repair, reducing inversion and axial rotation with inversion beyond that of intact ligaments. There were no significant differences in center-of-pressure excursion patterns between the Broström-Gould repair and the intact ligament condition, but this repair increased contact area beyond that with the ligaments intact. Graft reconstruction more closely restored inversion motion than did the Broström-Gould repair at 20° of plantar flexion but limited coupled axial rotation. Graft reconstruction also increased contact areas beyond the lateral ligament-deficient conditions but altered center-of-pressure excursion patterns relative to the intact condition.

CONCLUSIONS

No lateral ankle ligament reconstruction completely restored native contact mechanics of the ankle joint and hindfoot motion patterns.

In vivo kinematics of the tibiotalar joint after lateral ankle instability

BACKGROUND

Previous studies have suggested that injury to the anterior talofibular ligament (ATFL) may be linked to altered kinematics and the development of osteoarthritis of the ankle joint. However, the effects of ATFL injury on the in vivo kinematics of the ankle joint are unclear.

HYPOTHESIS

Based on the orientation of the ATFL fibers, ATFL deficiency leads to increased anterior translation and increased internal rotation of the talus relative to the tibia.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The ankles of 9 patients with unilateral ATFL injuries were compared as they stepped onto a level surface. Kinematic measurements were made as a function of increasing load. With use of magnetic resonance imaging and orthogonal fluoroscopy, the in vivo kinematics of the tibiotalar joint were measured in the ATFL-deficient and intact ankles of the same individuals.

RESULTS

A statistically significant increase in internal rotation, anterior translation, and superior translation of the talus was measured in ATFL-deficient ankles, as compared with the intact contralateral controls. For example, at 100% body weight, ATFL-deficient ankles demonstrated an increase of 0.9 +/- 0.5 mm in anterior translation (P = .008), an increase of 5.7 degrees +/- 3.6 degrees in internal rotation (P = .008), and a slight increase of 0.2 +/- 0.2 mm in the superior translation (P = .02) relative to the intact contralateral ankles.

CONCLUSION

Deficiency of the ATFL increases anterior translation, internal rotation, and superior translation of the talus.

CLINICAL RELEVANCE

Altered kinematics may contribute to the degenerative changes observed with chronic lateral ankle instability. These findings might help to explain the degenerative changes frequently observed on the medial talus in patients with chronic ATFL insufficiency and so provide a baseline for improving ankle ligament reconstructions aimed at restoring normal joint motion.

An anatomic and autologous lateral ankle stabilization

A new technique for stabilization of the lateral ankle ligaments is presented. The procedure uses a split peroneus longus tendon to recreate the calcaneofibular and anterior talofibular ligaments. The new ligaments follow a precise anatomic course that replicates the pathway of the original ligaments. The procedure also capitalizes on interference screw technology so that accurate ligament tension can be obtained. This technique is most useful for severe ligamentous insufficiency involving both the calcaneofibular and anterior talofibular ligaments. Biomechanical rationale for the use of peroneus longus is also discussed.

Intraarticular pressure distribution in the talocrural joint is related to lower leg muscle forces

BACKGROUND

It is of paramount importance to know the magnitude and the distribution of joint contact stress within the most heavily loaded structures of the human foot. In the talocrural joint role of external loading and loading applied by muscles on joint contact stress is not extensively studied. The purpose was to determine the distribution of joint contact stress of the talocrural joint with varying axial tibia loading and extrinsic tendon loading.

METHODS

Five cadaveric feet were studied in the intact condition and following transsection of ligaments under seventeen different loading conditions. Joint contact stress was determined from capacitive pressure sensors implanted in the talocrural joint when the specimens were loaded in a specially designed loading simulator. Different axial tibia and extrinsic tendon loads were applied. Motions of the bony structures were assessed by an optical motion analysis system.

FINDINGS

The anterior aspect of the joint is predominantly stressed in all loading conditions. The influence of muscle force on the internal joint contact stress distribution is higher than the axial shank loading. The biggest effect on joint contact stress was initiated by the tibialis posterior muscle. The flexor hallucis homogenizes the pressure distribution in intact joint conditions. Joint angles were not substantially changed by muscle force applications.

INTERPRETATION

The functions of the muscles of the lower leg are important for maintaining physiologic joint contact stress. Reducing the force potentials of certain muscle tendon units through surgeries, immobilization, fatigue or inappropriate footwear should change the joint contact stress. Such information is helpful to understand the physiological function of the foot. It might also explain the development and manifestation of certain foot pathologies.

Clinical outcome after anatomical reconstruction of the lateral ankle ligaments using the Duquennoy technique in chronic lateral instability of the ankle

We performed a retrospective study to assess the long-term outcome of non-augmented anatomical direct repair of the lateral ankle ligaments, as originally described by Duquennoy et al, for the treatment of chronic lateral instability of the ankle. This procedure aims to restore stability by the re-insertion and tightening of the original talofibular and calcaneofibular ligaments without division of the ligament. We examined the outcome in terms of the post-operative quality of life, the function of the joint and the development of osteoarthritis.

Between 1985 and 2002, 23 patients (11 males, 12 females) with a mean age of 32 years (15 to 58) who had undergone this procedure completed the Short-Form 36 assessment of quality of life and the Olerud and Molander Ankle score for the subjective evaluation of symptoms. Clinical re-evaluation, including examination of the ankle and the completion of the American Orthopaedic Foot and Ankle Society questionnaire was performed on 21 patients after a mean follow-up of 13 years (3 to 22.2). At the final follow-up radiographs of both ankles were taken to assess the development of osteoarthritis.

The mean total Short-Form 36 and Olerud and Molander Ankle scores in 23 patients at final follow-up were 79.6 points (37 to 100) and 81.6 points (40 to 100), respectively. The mean total post-operative American Orthopaedic Foot and Ankle Society score in 21 patients was 89.7 points (72 to 100). We found a significant post-operative reduction in talar tilt and anterior drawer sign (chi-squared test, p < 0.001). The functional outcome of the procedure was excellent in ten patients (48%), good in seven (33%) and fair in four (19%). The results in terms of ankle function and stability did not deteriorate with time and there was little restriction in movement.

This procedure is simple and effective with a very low rate of complications.

The assessment of ankle joint forces during the postural balance control movement

The purpose of this study was to calculate three-dimensional angular displacements, moments and joint reaction forces of the ankle joint during the waist pulling, and then, we assessed the reaction forces and bone-on-bone forces within ankle joint during postural balance control movement. With experiments and MATLAB simulation we could calculate ankle joint kinematic and kinetic data. The results presented in this study will be useful data for understanding the injury mechanism of ankle joint during postural balance control.

Reconstruction of the lateral ankle ligaments with allograft in patients with chronic ankle instability

The management of chronic lateral instability of the ankle remains controversial. In general, the anterior talofibular ligament (ATFL) must be reconstructed in all patients. Some will also need reconstruction of the calcaneofibular ligament (CFL) (or its function) to regain stability of both the ankle and the subtalar joints, and to avoid recurrence of instability. After reconstruction, most authors report good to excellent results in 80% to 85% of patients. We describe the augmented reconstruction technique of ATFL and CFL with a semitendinosus tendon allograft through a peroneal bone tunnel fixed with biodegradable anchors, and advocate this procedure as a safe, effective method to manage lateral ankle instability.

[Clinical gait analysis]

Clinical gait analysis comprises a well defined repertoire of various methods for valid and reliable assessment. The rapid development of corresponding hardware and software has substantially decreased the efforts necessary for data processing and has promoted the clinical applicability of the procedures. The clinical question defines the amount of methodological input. Clinical gait analysis may provide diagnostic insight into the pathobiomechanics and the pathophysiology of complex gait disorders for which a profound understanding of the underlying causes is a prerequisite for adequate treatment. The methods may help in the screening of gait function following reconstructive surgery as a measure of quality control, the assessment of the severity of a gait disturbance, the evaluation of a rehabilitation process, or the quantification of the effect of orthoses, insoles or specific shoe ware. Simple procedures of gait analysis may suffice to obtain information on gait function which can not be derived by mere clinical observation and which can be incorporated into a clinical concept.

Anatomical repair of lateral ligaments in patients with chronic ankle instability

In a prospective study, 19 patients with chronic ankle instability underwent clinical and radiographic reexaminations 36 months after anatomical reconstruction. In addition, dynamic pedography was conducted and peroneal reaction time measured on a tilting platform for an evaluation of functional aspects. Prior to this examination, 32 patients had been asked to fill in a questionnaire and make a detailed subjective evaluation of current discomfort, stability, flexibility and sporting abilities. Eighty-eight percent of the patients reported satisfactory results; only 3% complained of persistent instability. In 71% the ability to take part in sports had improved after surgery, and 85% of the patients reported unrestricted walking abilities. Supination ability was impaired in 5% of the patients at the follow-up. The radiographic examination showed restored ankle stability with a significant reduction of talar tilt and talar translation; a postoperative increase in signs and symptoms of arthrosis was not observed. Dynamic pedography showed a large degree of symmetry of plantar pressure distribution after surgery. There were no significant differences in peroneal reaction time in the repaired and intact ankles. The results of the study show that it is possible to restore ankle stability with anatomical reconstruction without impairing the range of movement in the ankle joint complex. Progressive osteoarthrosis can be prevented.

Clinical biomechanics of the peritalar joint

The peritalar joint includes the articulations between the talus and calcaneus and the talus and navicular. Motion between the talus and calcaneus is described most often as rotation about an axis that points medially, anteriorly, and superiorly. This motion is considered to be triplanar, with inversion, plantar flexion, and adduction occurring together, whereas eversion, dorsiflexion, and abduction are associated. Similar motions have been described between the talus and navicular. Foot deformity, such as a pes planus or a pes cavus foot type, and hindfoot or midfoot joint fusion can alter the biomechanics of the peritalar joint.

The effect of an ankle brace on the 3-dimensional kinematics and tibio-talar contact condition for lateral ankle sprains

Ten fresh-frozen cadaveric ankles were studied to investigate the effect of an ankle brace (Air-Stirrup) on the three-dimensional (3-D) motion and contact-pressure distribution of the talo-tibial joint with lateral ligamentous injury. Three-dimensional motion and contact-pressure distribution were simultaneously measured under dynamic conditions employing a direct linear-transformation technique and a dynamic-pressure sensor, respectively. Inversion increased significantly upon severing of the anterior talo-fibular (ATF) ligament and calcaneo-fibular (CF) ligaments; however, restoration to the intact level was observed following application of the ankle brace. Internal rotation also increased upon severing of the lateral ligaments in the plantar flexion; however, this difference was not altered by using the ankle brace. The contact area on the articular surface of the talus shifted from posterior to anterior between plantar flexion and dorsal flexion; additionally, a high pressure area was evident in the medial aspect of the talus following severing of the lateral ligaments. Upon application of the ankle brace, however, no significant changes were apparent in the contact condition. The results of this study suggest that stabilization against inversion is the major function of braces in terms of protection of ankle sprains. Ankle sprains, however, often occur in combinations of inversion, plantar flexion and internal rotation; therefore, restriction of plantar flexion and internal rotation may also be an important function of the ankle brace.