External ring fixation versus screw fixation for ankle arthrodesis: a biomechanical comparison

Evaluation of three fixation methods in tibiotalocalcaneal fusion for chronic osteomyelitis following ankle fracture

Introduction

In the scenario of chronic osteomyelitis following an ankle fracture, limb salvage and ideally infection eradication, can be an alternative to amputation.Tibiotalocalcaneal arthrodesis is perhaps the most popular procedure. When performing fusion in osteomyelitis patients, external fixation is more commonly used, although there is some experience with internal fixation. In this study, we conducted a retrospective evaluation of three groups of consecutively treated patients undergoing tibiotalocalcaneal fusion using either circular or monoplanar external fixation or an intramedullary nail coated with antibiotic-loaded cement. Our objective was to assess the success of each procedure in terms of consolidation, infection remission, and improvement in the quality of life.

Materials and methods

A multicenter, retrospective, study of 17 patients treated with tibiotalocalcaneal fusion, divided into three groups based on the treatment performed: Group A: retrograde intramedullary nail coated with Polymethylmethacrylate (PMMA) with antibiotic, Group B: monoplanar LRS (Limb Reconstruction System) external fixator, and Group C: circular external fixator; all with a minimum 12 month follow-up. Quality and percentage of consolidation were evaluated through tomography. Additionally, the SF-12 form was administered to assess the quality of life at the last follow-up visit.

Results

17 patients were evaluated. Group A: 6 patients, average tibiotalar and subtalar consolidation rates were 66.24 % and 67.06 %. One patient did not achieve infection healing. SF-12 scores averaged 40 for physical and 48.13 for mental. Group B: 5 patients; 3 active smokers. Average tibiotalar and subtalar consolidation rates were 52.78 % and 62.3 %, respectively. All patients achieved infection remission. SF-12 scores averaged 46.7 for physical and 51.3 for mental. Group C:6 patients, 1 diabetic and 3 smokers. Average tibiotalar and subtalar consolidation rates were 65.9 % and 65.7 %. Half experienced infection recurrence. SF-12 scores averaged 36.7 for physical and 47.8 for mental.

Conclusion

Patients with coated retrograde nails exhibit higher consolidation rates; and patients with circular external fixation had a higher infection recurrence rate. Establishing generalizable treatment algorithms for these patients remains challenging, but our data suggest a favorable trend toward the use of internal intramedullary fixation coated with PMMA.

A biomechanical study comparing the compression force and osseous area of contact of two screws fixation techniques used in ankle joint arthrodesis model

INTRODUCTION

Arthrodesis of a (diseased) ankle joint is usually performed to achieve pain relief and stability. One basic principle of arthrodesis techniques includes rigid fixation of the surfaces until union. It seems plausible that stable anchoring and homogeneous pressure distribution should be advantageous, however, it has not been investigated yet. The aim is to achieve uniform compression, as this is expected to produce favorable results for the bony fusion of the intended arthrodesis. Numerous implants with different biomechanical concepts can be used for ankle fusion. In this study, headless compression screws (HCS, DePuy Synthes, Zuchwil, Switzerland) were compared biomechanically to an alternative fixation System, the IOFix device (Extremity Medical, Parsippany, NJ, USA) in regard to the distribution of the compression force (area of contact) and peak compression in a sawbone arthrodesis-model (Sawbones® Pacific Research Laboratories, Vashon, WA, USA). This study aims to quantify the area of contact between the bone interface that can be obtained using headless compression screws compared to the IOFix. In current literature, it is assumed, that a large contact surface with sufficient pressure between the bones brings good clinical results. However, there are no clinical or biomechanical studies, that describe the optimal compression pressure for an arthrodesis.

MATERIAL AND METHODS

Two standardized sawbone blocks were placed above each other in a custom-made jig. IOFix and headless compression screws were inserted pairwise parallel to each other using a template for a uniform drilling pattern. All screws were inserted with a predefined torque of 0.5 Nm. Pressure transducers positioned between the two sawbone blocks were compressed for the measurement of peak compression force, compression distribution, and area of contact.

RESULTS

With the IOFix, the compression force was distributed over significantly larger areas compared to the contact area of the HCS screws, resulting in a more homogenous contact area over the entire arthrodesis surface. Maximum compression force showed no significant difference.

CONCLUSION

The IOFix system distributes the compression pressure over a much larger area, resulting in more evenly spread compression at the surface. Clinical studies must show whether this leads to a lower pseudarthrosis rate.

Sustentaculum fracture fixation with lateral plate or medial screw fixation are equivalent

BACKGROUND

Fixation of sustentaculum tali fractures is important to maintain the biomechanical function of the subtalar joint. A common method of fixation is securing the sustentacular fragment by way of a laterally based locking plate (LP). A medial approach with a single screw (MS) has been proposed as an alternative method of fixation.

METHODS

Five pairs of formalin-preserved cadaveric ankles with the subtalar joint and interosseous ligaments intact ("osseous cadavers") and four pairs of fresh-frozen cadaveric ankles with soft-tissue preserved dissected from mid-tibia down ("soft tissue cadavers") were used in the study. The left ankle was randomly assigned to one of the two fixation methods (LP or MS), while the right ankle was the opposite. These same steps for fixation were repeated for six synthetic ankle models. All models were loaded with a body mass of 80 kg. Statistical differences between LP and MS stiffness were determined using a paired t-test in cadavers and un-paired t-tests in synthetic ankles.

RESULTS

For osseous cadaveric ankles, LP demonstrated a mean stiffness of 232.95(SD: 59.96) N/mm, while MS was 239.72(SD:131.09) N/mm (p = 0.9293). For soft tissue cadaveric ankles, LP mean stiffness was 133.58(SD:37.84) N/mm, while MS was 134.88(SD:20.75) N/mm (p = 0.9578). For synthetic ankles, LP mean stiffness was 220.40(SD:81.93) N/mm, while MS was 261.50(SD:100.21) N/mm (p = 0.6116).

CONCLUSIONS

Across all three models, there was no significant difference between LP and MS methods. Retrospective observational studies are recommended to assess patient outcomes from each of the methods.

Role of fibular autograft in ankle arthrodesis fixed using cannulated screws: a proportional meta-analysis and systematic review

Ankle arthrodesis is commonly performed to treat end-stage ankle osteoarthritis. The aim of this study was to determine whether the use of fibular autograft might increase the fusion rate and decrease the complication rate in ankle arthrodesis (AA) fixed using cannulated screws. To perform this PRISMA-compliant proportional meta-analysis, multiple databases were searched for studies in which patients undergone AA (using exclusively cannulated screws and augmented with fibular bone graft) were followed. The characteristics of the cohort, the study design, surgical details, the nonunion and complication rate at the longest follow-up were extracted and recorded. The modified Coleman Methodology Score (mCMS) was applied to appraise the quality of studies. Two groups were built: arthrodeses fixed with screws combined with cancellous autograft (G1) and arthrodeses fixed with screws combined with cancellous autograft and augmented with a lateral fibular onlay (G2). A third group (arthrodeses fixed with screws and no graft, G3) was extracted from previous literature for a further comparison. Overall, we included 306 ankles (296 patients) from ten series (ten studies). In G1 and G2 there were 118 ankles (111 patients) and 188 ankles (185 patients), respectively. In patients where cancellous autograft was used, a further augmentation with a fibular lateral strut autograft did not change significantly the nonunion (4% [95% CI 1-9] in G1 vs. 2% [95% CI 0-5) in G2, p = 0.99) nor the complication rate (18% [95% CI 0-36] in G1 vs. 13% [95% CI 6-21) in G2, p = 0.71). Upon comparison with 667 ankles (659 patients, G3) in which arthrodeses had been performed without grafting, the nonunion and complication rates did not differ significantly either (pooled estimates: 3% [95% CI 1-3) in G1 + G2 vs. 3% [95% CI 2-4] in G3, p = 0.73 for nonunion; 15% [8-23] in G1 + G2 vs. 13% [95% CI 9-17] in G3, p = 0.93 for complications). In ankle arthrodesis fixed with cannulated screws combined with cancellous autograft at the fusion site, a construct augmentation with a distal fibular onlay strut graft positioned laterally at the ankle joint does not reduce the risk of nonunion or complication. In general, the use of bone graft does not influence significantly the nonunion nor the complication rate as compared to non-grafted screw-fixed ankle arthrodeses.Kindly check and confirm the corresponding author mail id is correctly identified.It's all correct.

Irritation from metalwork after ankle arthrodesis fixed using screws: a proportional meta-analysis and systematic review

OBJECTIVE

Ankle arthrodesis (AA) is often fixed using cannulated screws. The irritation from metalwork is a relatively common complication, but there is no consensus regarding the need to remove the screws on a systematic basis. The aim of this study was to determine (1) the proportion of screws removed after AA and (2) whether predictors of screw removal could be identified.

METHODS

This PRISMA-compliant systematic review was part of a larger previous protocol registered on the PROSPERO platform. Multiple databases were searched including studies in which patients undergone AA using screws as exclusive fixation method were followed. Data were harvested regarding the cohort, the study design, the surgical technique, the nonunion and complication rate at the longest follow-up. Risk of bias was assessed using the modified Coleman Methodology Score (mCMS).

RESULTS

Forty-four series of patients from thirty-eight studies (1990 ankles, 1934 patients) were selected. The average follow-up was 40.8 months (range 12-110). In all studies, hardware was removed due to symptoms reported by patients and related to the screws. The pooled proportion of removal of metalwork was 3% (95% CI 2-4). The pooled proportion of fusion was 96% (95%CI 95-98), while the pooled proportion of complications and reoperations (excluding the removal of metalwork) stood at 15% (95% CI 11-18) and 3% (95% CI 2-4), respectively. The mean mCMS (50.8 ± 8.1, range 35-66) revealed only an overall fair quality of studies. The univariate analysis and the multivariate model showed that the year of publication (R = - 0.004; p = 0.01) and the number of screws (R = 0.08; p = 0.01) were associated with the screw removal rate. Specifically, we found that over time the removal rate decreased by 0.4% per year and that the use of three screws instead of two reduced the risk of removal of metalwork by 8%.

CONCLUSIONS

In this review, removal of metalwork after ankle arthrodesis using cannulated screws was needed in 3% of cases at an average follow-up of 40.8 months. It was indicated only in case of symptoms related to soft tissue irritation from screws. The use of three screws was paradoxically related to a reduced risk of removal of screws as compared to two-screw constructs.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV.

Low Preoperative Albumin Associated With Increased Risk of Superficial Surgical Site Infection Following Midfoot, Hindfoot, and Ankle Fusion

BACKGROUND

This study investigates the effect of malnutrition, defined by hypoalbuminemia, on rates of complication, readmission, reoperation, and mortality following midfoot, hindfoot, or ankle fusion.

METHODS

The National Surgical Quality Improvement Program (NSQIP) database was queried from 2005 to 2019 to identify 500 patients who underwent midfoot (n = 233), hindfoot (n = 261), or ankle (n = 117) fusion. Patients were stratified into normal (n = 452) or low (n = 48) albumin group, which was defined by preoperative serum albumin level <3.5 g/dL. Demographics, medical comorbidities, hospital length of stay (LOS), and 30-day complication, readmission, and reoperation rates were compared between groups. The mean age of the cohort was 58.7 (range, 21-89) years.

RESULTS

Hypoalbuminemia patients were significantly more likely to have diabetes (P < .001), be on dialysis (P < .001), and be functionally dependent (P < .001). The LOS was significantly greater among the low albumin group (P < .001). The hypoalbuminemia cohort also exhibited a significantly increased likelihood of superficial infection (P = .048). Readmission (P = .389) and reoperation (P = .611) rates did not differ between the groups.

CONCLUSION

This study shows that malnourished patients have an increased risk of superficial infection following foot and ankle fusions but are not at an increased risk of readmission or reoperation, suggesting that low albumin confers an elevated risk of surgical site infection.

LEVELS OF EVIDENCE

Level III, Retrospective cohort study.

Ilizarov Ankle Arthrodesis: A Simple Salvage Solution for Failed and Neglected Ankle Fractures

BACKGROUND

Infection around the ankle joint after fracture fixation, or septic arthritis with active discharging sinuses is often challenging to manage with conventional procedures of arthrodesis. The Ilizarov method of arthrodesis gives a better alternative for salvage in such cases.

METHODS

This was a retrospective study including 20 patients who were subjected to tibiotalar arthrodesis with Ilizarov method. The major pathologies included internal fixation of ankle fractures complicated by infection, posttraumatic infected ankle arthritis, and osteomyelitis. The patients were evaluated on the basis of Association for the Study and Application of the Method of Ilizarov (ASAMI) criteria. The aim of the surgery was to achieve plantigrade, stable, and painless foot with no signs of infection.

RESULTS

A total of 20 patients were operated and reviewed at our institute. The study comprised of 15 male and 5 female patients with a mean age of 43.9 years (range 33-55 years). Out of 20 patients, 4 patients had complications of pin-tract infection and one had wire breakage of the forefoot ring. According to the ASAMI criteria, 17 patients had excellent bone scores and 18 patients had good functional scores. Union was achieved in all patients with resolution of infection and the mean limb length discrepancy was 1.92 cm (range 1-2.5 cm).

CONCLUSIONS

The Ilizarov fixator for ankle arthrodesis provides an excellent way for strong bone fusion, infection eradication, early weight-bearing, and the added benefits of compression at the arthrodesis site post-operatively.

Analysis of the Effect of Posterior Lateral Malleolus Plate Fixation on the Curative Effect and Mechanical Stability of Complex Ankle Fractures

This paper investigates the effect of lateral and posterior 1/3 tubular plate bone plate fixation on the curative effect, wound healing, and mechanical stability of complex ankle fracture. 80 patients with complex ankle fractures treated in our hospital from January 2018 to July 2020 are selected for the study, and 80 patients are randomly divided into posterior fixation group and lateral fixation group according to the number table method, with 40 patients in each group. Patients in the posterior malleolus fixation group are treated with posterior lateral malleolus plate fixation, and patients in the lateral malleolus fixation group are treated with lateral malleolus plate fixation. The differences in efficacy, mechanical stability, wound healing, visual analog scale (VAS) pain score, and American Association of Foot and Ankle Surgery (AOFAS) ankle function are compared. The subjects are followed up for 6 months until January 2022. In patients with complex ankle fracture, 1/3 tubular plate osteoplate fixation in the posterior lateral malleolus can improve clinical efficacy and mechanical stability, which is helpful to promote incision healing and reduce the risk of complications. The 1/3 tubular plate osteoplate fixation in the posterior lateral malleolus is worthy of clinical promotion and application.

One-stage tibial deformity correction and ankle arthrodesis for ankle osteoarthritis and tibial malalignment after low tibial osteotomy

Introduction

There are no reports on one-stage corrective tibial opening wedge osteotomy and arthrodesis for osteoarthritis of the ankle and tibial malalignment after distal tibial osteotomy.

Presentation of case

The patient was a 70-year-old woman who presented with complaints of ankle pain and lower limb deformity after tibial osteotomy performed for ankle arthritis 17–18 years earlier. Clinical examination revealed marked swelling around the ankle joint and pain and tenderness at the joint line. Imaging showed tibial malalignment and severe osteoarthritic changes in the ankle. The patient had valgus deformity of 21° and recurvatum deformity of 4°. In two months, she admitted to Department of Orthopedics at Tokushima University Hospital in Japan and we performed one-stage corrective tibial opening wedge osteotomy and ankle arthrodesis with an anterolateral plate through a lateral longitudinal incision. After removal of the previous implants, the remaining articular cartilage and osteophytes were removed from the tibial and talar surfaces. After debridement of the talar trochlea and tibial plateau, the center of rotation and angular deformity of the tibia was cut transversely and a 1-cm bone graft obtained from the removed fibula was inserted into the osteotomy site, which decreased the tibial malalignment. An anterolateral locking plate was inserted over the anterior and lateral sides of the tibia, and the ankle was fused using 2 cannulated screws.

Discussion

The patient wore an above-knee splint for 6 weeks to avoid weight-bearing followed by gradual weightbearing with a brace thereafter. Osseous fusion was achieved after about 3.5 months. Radiographs obtained at the 2-year follow-up visit showed complete union of the tibia and talus. Full correction of valgus and recurvatum deformity was achieved, and the patient was able to perform daily activities with almost no pain.

Conclusion

We reported a rare case of ankle osteoarthritis and tibial malalignment that was successfully treated with one-stage corrective tibial opening wedge osteotomy and ankle arthrodesis using an anterolateral plate via a transfibular approach.

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Ankle osteoarthritis and malalignment can be followed by osteotomy.

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One-stage ankle arthrodesis and deformity correction should be considered.

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Anterolateral plate was useful for arthrodesis and correction.

Treatment of hindfoot and ankle infections with Ilizarov external fixator or spacer, followed by secondary arthrodesis

An established treatment strategy in surgical site infection after hindfoot and ankle surgery is a two-stage procedure with debridement and placement of a cement spacer, followed by antibiotic treatment and secondary arthrodesis. However, there is little evidence to favor this treatment over a one-stage procedure with debridement, followed by primary arthrodesis with an Ilizarov external fixator and antibiotic treatment. We compared the infection control and clinical and radiological outcome of a two-stage and a one-stage procedure. In this study, 7 patients with a two-stage revision and 11 patients with a one-stage revision between 2005 and 2015 were included. The primary outcome was infection control (absence of the Musculoskeletal Infection Society PJI criteria) 2 years after the ankle or hindfoot arthrodesis. Secondary outcome measures were the AOFAS hindfoot score and radiological consolidation rate. Infection control was 85% (6 out of 7 patients) in the two-stage group and 81% (9 out of 11 patients) in the one-stage group (p = 1.0). One patient (14%) of the two-stage and two patients (18%) in the one-stage group needed below-knee amputation. In the two-stage group, the mean postoperative AOFAS score was 74.8 (SD: ±11.3) versus 71.7 (SD: ±17.8) in the one-stage group. Radiological consolidation could be achieved in 71% in the spacer group (n = 5) and in 72% in the Ilizarov external fixator group (n = 9). Infection control, AOFAS score, and radiologic consolidation of hindfoot and ankle arthrodesis were comparable in both groups of patients with complicated postsurgical hindfoot or ankle infections.

Short- to Midterm Follow-up of Cemented Total Ankle Replacement Using the INBONE II: A Retrospective Chart Review

Background: Total ankle arthroplasty is a viable option for the treatment of end stage ankle arthritis. The purpose of this study is to report on the mid-term results with a cemented total ankle prosthesis, the Inbone™ II implant over a 5 year period. Methods: A retrospective, single-center chart and radiographic review of all patients with end stage ankle arthritis treated with Inbone™ II TAR) as the primary index procedure from 12/1/2012 to 3/1/2017. Clinical data were evaluated at 3 month, 6 month, 1 year and subsequent intervals for the study period. Preoperative diagnosis, pertinent patient demographics adjunctive procedures, implant associated complications, subsequent surgeries, and revisions were recorded. Results: 121 total ankles met our inclusion criteria. Patients had an INBONE™ II TAR implant placed with bone cement with a minimum of a 12 months follow up. Average age was 62.88 (range, 32-87) years, average body mass index was 32.74 (range, 21.8-56.04) kg/m2 and average follow up was 28.51(range, 12-69) months. Using the COFAS complication classification there were 14 minor, 11 moderate, and 5 major complications. 6/121 (5.0%) revisions which included: polyethylene exchange, device explant/fusion, and antibiotic spacer in situ. No complications over the course of this study ended in amputation. Conclusion: Total Ankle Arthroplasty utilizing the cemented INBONE™ II yielded good midterm results with regards to minor, moderate, and major complications. Rate of revision 6/121 (5.0%) was within the reported range with only 5 patients converted to fusion during the study period resulting in a 95% survivability at mid-term follow up.Levels of Evidence: Level IV: Retrospective case series.

Results and Outcomes of Combined Cross Screw and Ilizarov External Fixator Frame in Ankle Fusion

Ankle fusion is a treatment option for end-stage ankle arthritis. Fusion site stability and optimal foot positioning are crucial parameters. We present the results of our double fixation technique, combining both cross-screw fixation and Ilizarov external fixator frame via transmalleolar approach. We reviewed the files from 52 patients operated for ankle fusion in our center. In our technique, we use a transmalleolar approach, initial stabilization with 2 cannulated, half-threaded cross screws, and final stabilization with an Ilizarov external fixator frame. Fusion stability, weightbearing time, complication rates, and final functional scores were recorded and evaluated. Mean frame removal time was 11.2 ± 2.1 weeks, and 71.6% of patients were fully weightbearing at that time. Absolute fusion stability was reported in 88.46% of patients at that time, while no pseudarthrosis was noted in final follow-up at 12 months. According to the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot-ankle score evaluation at 12 months, 90.4% of patients reported excellent and 9.6% good results. None of the patients was referred for symptomatic forefoot arthritis, and there were no cases of deep infection or deep vein thrombosis. Material-related complications were reported in 1 patient who was treated with implant removal after 1 year. Ankle fusion is a salvage procedure that offers optimal results in end-stage ankle arthritis. Our technique offers absolute fusion site stability with excellent functional results, minor complications, and the advantages of early protected weightbearing. Careful patient selection in addition to fine foot positioning should be regarded as crucial for the final outcome.

Salvage arthrodesis for infected ankle fractures with segmental bone-loss using Ilizarov concepts: a prospective study

PURPOSE

Complex ankle fractures accompanied with infection and segmental bone loss are a worrying issue. This prospective study was conducted to explore the effectiveness of using Ilizarov concepts in achieving salvage arthrodesis and reconstructing post-debridement defects in such complicated scenarios.

METHODS

A total of 44 consecutive patients (mean age 35.61 ± 8.57 years, 30 males, 44 feet) of post-traumatic infected ankle fractures, who met our selection criteria, were enrolled and subjected to radical debridement and salvage arthrodesis using the bifocal bone transport concepts of Ilizarov. All patients were treated between 2012 and 2017 either by acute shortening compression of the arthrodesis site with re-lengthening (ASRL) through the created proximal metaphyseal osteotomy (group I, n = 20) or by gradual bone transport (BT) through the proximal osteotomy with gradual closure of the distal ankle defect (group II, n = 24). Plain-radiographs were used for radiological assessment. Clinically, the outcomes were objectively graded according to the Hawkins criteria, while subjectively the patients reported their satisfaction on a 1-5 points acceptance scale.

RESULTS

The mean follow-up was 37.16 ± 5.31 (30-48 months). Successful fusion was achieved in 43/44 patients, with a significantly (P < 0.05) lesser needs for bone-grafting in favour of group II. The results were good in 32 cases, fair in 11, and poor in a single case with no significant difference between the two groups. The acceptance scores were significantly (P < 0.05) superior in group II (3.08 ± 1.1 points) than that group I (2.25 ± 1.4 points).

CONCLUSIONS

Bifocal bone transport is effective in salvaging troublesome infected ankle fractures with bone loss. BT is more comprehensive and acceptable than ASRL with lesser needs for bone grafting.

External versus internal fixation for arthrodesis of chronic ankle joint infections - A comparative retrospective study

BACKGROUND

Arthrodesis of the ankle is a salvage procedure in case of chronic ankle joint infection. External fixation still is the gold standard. We compared the outcome of external fixator versus intramedullary nailing for arthrodesis of the infected ankle joint.

METHODS

All patients with ankle joint infection who received arthrodesis with either external fixator or intramedullary nail between 08/2009 and 09/2017 were retrospectively analyzed. Endpoints were the successful control of infection, osseous fusion, and mobilization with full weightbearing.

RESULTS

Seventy-one patients were included. Nineteen patients (27%) suffered reinfection. Patients with intramedullary nailing showed significantly fewer reinfections (p=0.019), achieved full weightbearing significantly more often (p=0.042) and faster and developed significantly fewer complications (p<0.001). Forty-three patients showed bone fusion without significant differences between the groups.

CONCLUSIONS

Ankle arthrodesis with intramedullary nailing appears to be a successful alternative to the established procedure of external fixation in cases of chronic ankle joint infection.

A Comparison of Talar Surface Area Occupied by 2- Versus 3-Screw Fixation for Ankle Arthrodesis

Background. Ankle arthrodesis is a procedure utilized in the treatment of end-stage ankle arthritis. Internal fixation with screws is traditionally relied on to achieve union. Although the use of screw fixation alone has produced satisfactory outcomes, nonunion rates can range from 9% to as high as 35%. Adding an additional screw to the traditional 2-screw fixation construct may improve the likelihood of union by adding strength and stiffness; however, this addition may counteract the theoretical fusion enhancement benefit by reducing the joint surface area (SA) available for fusion. Methods. A cadaver study was performed to compare the amount of SA lost from a standard 2-screw (group 1) versus the 3-screw ankle fusion construct (group 2). A total of 10 fresh cadaveric below-knee specimens were used. Cannulated 7.0-mm partially threaded screws were placed across the ankle joint. Each talus was examined to precisely determine joint SA loss following each procedure. Results. The mean total talus SA in group 1 was 1833.71 mm² compared with 2125.76 mm² in group 2. The mean SA lost by the 2-screw construct was 5.91%, versus 9.51% in the 3-screw construct group. The talus SA loss percentage difference between groups reached statistical significance (P = .0220). Conclusion. The addition of a third 7.0-mm screw to a 2-screw ankle fusion construct raised the percentage of joint surface lost from 5.91% to 9.5%. Clinical Relevance. Surgeons may consider using extra-articular plates with 1 or 2 intra-articular screws instead of the traditional 3-screw construct if there is an elevated concern for nonunion. Levels of Evidence: Level IV: Cadaveric case series.

Biomechanical comparison of conventional versus modified technique in distal chevron osteotomies of the first metatarsal: A cadaver study

BACKGROUND

Distal chevron osteotomy can be performed using a conventional or a modified technique. The aim of this biomechanical study was to compare the stability of the two techniques.

METHODS

Eighteen first metatarsals from nine pairs of fresh frozen human cadaver feet were used. A distal chevron osteotomy was performed using the conventional technique in group 1 (n=9) and using the modified technique in group 2 (n=9). The head of the first metatarsals was loaded in two different configurations (cantilever and physiological), using a materials testing machine.

RESULTS

In the cantilever configuration, the relative stiffness of the osteosynthesis in comparison with intact bone was 60% (±21%) in group 1 and 65% (±25%) in group 2 (p=0.61). In the physiological configuration, it was 47% (±29%) in group 1 and 47% (±21%) in group 2 (p=0.98). The failure strength in the cantilever configuration was 235N (±128N) in group 1 and 210N (±107N) in group 2 (p=0.47).

CONCLUSIONS

The conventional and the modified technique for distal chevron osteotomy in the treatment of hallux valgus show a comparable biomechanical loading capacity in this cadaver study.

Clinical evaluation of ankle arthrodesis with Ilizarov fixation and internal fixation

Background

Ankle arthrodesis may have internal or external stabilization.

We assessed whether the type of stabilization after ankle arthrodesis will affect: (1) functional outcome in Foot and Ankle Ability Measure (FAAM) scale, (2) pain level, (3) period of hospitalization, (4) rate of complications.

Methods

We retrospectively studied 47 individuals after ankle arthrodesis with Ilizarov fixation (group 1, n = 21) and internal stabilization (group 2, n = 26) at our institution in years 2007–2015. Clinical outcomes were measure by: (1) functional outcome in FAAM scale, (2) pain level, (3) period of hospitalization, (4) rate of complications.

Results

Total number of complications in Ilizarov group was 13, which corresponded to 0.62 complications per patient on average. In group 2 there were 15 complications, which corresponded to 0.58 complications per patient on average. The intergroup difference in rate of complications was not statistically significant (p = 0.066). In group 1 the mean VAS pain level before treatment was 4.69 and after treatment was 1.5 (p = 0.037). In group with internal stabilization the mean VAS pain level before treatment was 4.71 and after treatment was 2.9 (p = 0.044). In group 1 the mean period of hospitalization was 5.29 days, in group 2 was 5.71 days (p = 0.517). In group 1 the mean functional outcome in FAAM scale was 79.38, in group 2 was 70.11 (p = 0.458).

Conclusions

Ankle arthrodesis with Ilizarov stabilization is associated with lower prevalence of VAS pain level after surgery than after internal screws stabilization. Rate of complications, FAAM functional score and period of hospitalization were not statistically significant between group 1 and 2. Clinical outcome was satisfactory in group 1 and 2, but outcomes in Ilizarov group were slightly better than after internal stabilization.

Biomechanical Comparison of Fixation With a Single Screw Versus Two Kirschner Wires in Distal Chevron Osteotomies of the First Metatarsal: A Cadaver Study

Distal chevron osteotomy is a common procedure for surgical correction of hallux valgus. Osteosynthesis with 1 screw or 2 Kirschner wires has been commonly used. We compared the stability of the 2 techniques in distal chevron osteotomy. Sixteen first metatarsals from fresh-frozen human cadaver feet (9 different cadaveric specimens) were used. A standardized distal chevron osteotomy was performed. One first metatarsal from each pair was assigned to group 1 (3.5-mm cortical screw; n = 8) and one to group 2 (two 1.6-mm Kirschner wires; n = 8). Using a materials testing machine, the head of the first metatarsals was loaded in 2 different configurations (cantilever and physiologic) in succession. In the cantilever configuration, the relative stiffness of the osteosynthesis compared with intact bone was 59% ± 27% in group 1 and 68% ± 18% in group 2 (p = .50). In the physiologic configuration, it was 38% ± 25% in group 1 and 35% ± 7% in group 2 (p = .75). The failure strength in the cantilever configuration was 187 ± 105 N in group 1 and 259 ± 71 N in group 2 (p = .21). No statistically significant differences were found in stability between the 2 techniques. The use of 1 screw or 2 Kirschner wires had no significant differences in their biomechanical loading capacity for osteosynthesis in distal chevron osteotomies for treatment of hallux valgus.

Comparison of Monolateral External Fixation and Internal Fixation for Skeletal Stabilisation in the Management of Small Tibial Bone Defects following Successful Treatment of Chronic Osteomyelitis

Background

To compare the salvage rate and complication between internal fixation and external fixation in patients with small bone defects caused by chronic infectious osteomyelitis debridement.

Methods

125 patients with chronic infectious osteomyelitis of tibia fracture who underwent multiple irrigation, debridement procedure, and local/systemic antibiotics were enrolled. Bone defects, which were less than 4 cm, were treated with bone grafting using either internal fixation or monolateral external fixation. 12-month follow-up was conducted with an interval of 3 months to evaluate union of bone defect.

Results

Patients who underwent monolateral external fixation had higher body mass index and fasting blood glucose, longer time since injury, and larger bone defect compared with internal fixation. No significant difference was observed in incidence of complications (23.5% versus 19.3%), surgery time (156 ± 23 minutes versus 162 ± 21 minutes), and time to union (11.1 ± 3.0 months versus 10.9 ± 3.1 months) between external fixation and internal fixation. Internal fixation had no significant influence on the occurrence of postoperation complications after multivariate adjustment when compared with external fixation. Furthermore, patients who underwent internal fixation experienced higher level of daily living scales and lower level of anxiety.

Conclusions

It was relatively safe to use internal fixation for stabilization in osteomyelitis patients whose bone defects were less than 4 cm and infection was well controlled.

Radiological evaluation of ankle arthrodesis with Ilizarov fixation compared to internal fixation

INTRODUCTION

We asked whether the type of ankle joint arthrodesis stabilization will affect: (1) rate of union, (2) rate of adjacted-joint arthritis, (3) malalignment of the ankle joint.

MATERIAL AND METHODS

We retrospectively radiological studied 62 patients who underwent ankle arthrodesis with Ilizarov external fixator stabilization (group 1,n=29) or internal stabilization (group 2,n=33) from 2006 to 2015. Radiologic outcomes were mesure by: (1) rate of union, (2) rate of adjacent-joint arthritis, (3) malalignment of the ankle joint. The Levene's test,Mann-Whitney U test and Students t-test were used to the statistical analyses.

RESULTS

Ankle fusion was achieved in 100% of patients treated with external fixation and in 88% with internal stabilization. Desired frontal plane alignment was achieved in 100% of patients with external fixation and 76% with internal stabilization. Desired sagittal plane alignment was achieved in 100% of external fixation and 85% of internal stabilization. A total of 14 (48.3%) patients from group 1 showed a radiographic evidence of pre-existing adjacent-joint OA. The radiographic evidence of pre-existing adjacent-joint OA was also found in 27(81.8%) subjects from group 2. Alterations of adjacent joints were also found on postoperative radiograms of 19 (65.5%) patients subjected to Ilizarov fixation and in all 33 patients from group 2.

DISCUSION

Ilizarov fixation of ankle arthrodesis is associated with lower prevalence of adjacent-joint OA and ankle joint misalignment,and with higher fusion rates than after internal fixation.Although achieving a complex ankle fusion is generally challenging,radiological outcomes after fixation with the Ilizarov apparatus are better than after internal stabilization.

Operative Fixation Options for Elective and Diabetic Ankle Arthrodesis

Ankle arthrodesis remains one of the most definitive treatment options for end-stage arthritis, paralysis, posttraumatic and postinfectious conditions, failed total ankle arthroplasty, and severe deformities. The general aims of ankle arthrodesis are to decrease pain and instability, correct the accompanying deformity, and create a stable plantigrade foot. Several surgical approaches have been reported for ankle arthrodesis with internal fixation options. External fixation has also evolved for ankle arthrodesis in certain clinical scenarios. This article provides a comprehensive analysis of midterm to long-term outcomes for ankle arthrodesis using internal and/or external fixation each for elective and diabetic conditions.

Ankle Arthrodesis Versus Total Ankle Arthroplasty

Reoperation rates are higher in total ankle arthroplasties (TAAs) compared with ankle arthrodesis. Infection rates for primary TAAs are 1.4% to 2.4%. The survival rate of TAA is approximately 75% to 90% at 10 years. Arc of motion is maintained with TAAs compared with ankle arthrodesis. Ankle arthrodesis increases arc of motion through the talonavicular joint. Several factors are strong reasons to favor ankle fusion rather than TAA. TAA and ankle arthrodesis are effective treatments of end-stage ankle arthritis but the choice must be tailored to individual patients.

Surgical Treatment Options for the Diabetic Charcot Hindfoot and Ankle Deformity

Charcot neuroarthropathy is associated with progressive, noninfectious, osteolysis-induced bone and joint destruction. When the ankle and/or hindfoot is affected by the destruction process, management is further complicated with collapse and destruction of the talar body, which increases instability around the ankle. In this patient population, arthrodesis is the most commonly used surgical procedure. Internal fixation, external fixation, or a combination of both can be used for the treatment. Decision making between them should be individualized according to the patient characteristics.

New Technique for Tibiotalar Arthrodesis Using a New Intramedullary Nail Device: A Cadaveric Study

Introduction. Ankle arthrodesis is performed in a variety of methods. We propose a new technique for tibiotalar arthrodesis using a newly designed intramedullary nail. Methods. We proposed development of an intramedullary device for ankle arthrodesis which spared the subtalar joint using a sinus tarsi approach. Standard saw bones models and computer assisted modeling and stress analysis were used to develop different nail design geometries and determine the feasibility of insertion. After the final design was constructed, the device was tested on three cadaveric specimens. Results. Four basic nail geometries were developed. The optimal design was composed of two relatively straight segments, each with a different radius of curvature for their respective tibial and talar component. We successfully implemented this design into three cadaveric specimens. Conclusion. Our newly designed tibiotalar nail provides a new technique for isolated tibiotalar fusion. It utilizes the advantages of a tibiotalar calcaneal nail and spares the subtalar joint. This design serves as the foundation for future research to include compression options across the tibiotalar joint and eventual transition to clinical practice.

Biomechanical Comparison of External Fixation and Compression Screws for Transverse Tarsal Joint Arthrodesis

BACKGROUND

Transverse tarsal joint arthrodesis is commonly performed in the operative treatment of hindfoot arthritis and acquired flatfoot deformity. While fixation is typically achieved using screws, failure to obtain and maintain joint compression sometimes occurs, potentially leading to nonunion. External fixation is an alternate method of achieving arthrodesis site compression and has the advantage of allowing postoperative compression adjustment when necessary. However, its performance relative to standard screw fixation has not been quantified in this application. We hypothesized that external fixation could provide transverse tarsal joint compression exceeding that possible with screw fixation.

METHODS

Transverse tarsal joint fixation was performed sequentially, first with a circular external fixator and then with compression screws, on 9 fresh-frozen cadaveric legs. The external fixator was attached in abutting rings fixed to the tibia and the hindfoot and a third anterior ring parallel to the hindfoot ring using transverse wires and half-pins in the tibial diaphysis, calcaneus, and metatarsals. Screw fixation comprised two 4.3 mm headless compression screws traversing the talonavicular joint and 1 across the calcaneocuboid joint. Compressive forces generated during incremental fixator foot ring displacement to 20 mm and incremental screw tightening were measured using a custom-fabricated instrumented miniature external fixator spanning the transverse tarsal joint.

RESULTS

The maximum compressive force generated by the external fixator averaged 186% of that produced by the screws (range, 104%-391%). Fixator compression surpassed that obtainable with screws at 12 mm of ring displacement and decreased when the tibial ring was detached. No correlation was found between bone density and the compressive force achievable by either fusion method.

CONCLUSION

The compression across the transverse tarsal joint that can be obtained with a circular external fixator including a tibial ring exceeds that which can be obtained with 3 headless compression screws. Screw and external fixator performance did not correlate with bone mineral density. This study supports the use of external fixation as an alternative method of generating compression to help stimulate fusion across the transverse tarsal joints.

CLINICAL RELEVANCE

The findings provide biomechanical evidence to support the use of external fixation as a viable option in transverse tarsal joint fusion cases in which screw fixation has failed or is anticipated to be inadequate due to suboptimal bone quality.

Complex ankle arthrodesis: Review of the literature

Complex ankle arthrodesis is defined as an ankle fusion that is at high risk of delayed and nonunion secondary to patient comorbidities and/or local ankle/hindfoot factors. Risk factors that contribute to defining this group of patients can be divided into systemic factors and local factors pertaining to co-existing ankle or hindfoot pathology. Orthopaedic surgeons should be aware of these risk factors and their association with patients' outcomes after complex ankle fusions. Both external and internal fixations have demonstrated positive outcomes with regards to achieving stable fixation and minimizing infection. Recent innovations in the application of biophysical agents and devices have shown promising results as adjuncts for healing. Both osteoconductive and osteoinductive agents have been effectively utilized as biological adjuncts for bone healing with low complication rates. Devices such as pulsed electromagnetic field bone stimulators, internal direct current stimulators and low-intensity pulsed ultrasound bone stimulators have been associated with faster bone healing and improved outcomes scores when compared with controls. The aim of this review article is to present a comprehensive approach to the management of complex ankle fusions, including the use of biophysical adjuncts for healing and a proposed algorithm for their treatment.

Complex ankle arthrodesis: Review of the literature

Complex ankle arthrodesis is defined as an ankle fusion that is at high risk of delayed and nonunion secondary to patient comorbidities and/or local ankle/hindfoot factors. Risk factors that contribute to defining this group of patients can be divided into systemic factors and local factors pertaining to co-existing ankle or hindfoot pathology. Orthopaedic surgeons should be aware of these risk factors and their association with patients’ outcomes after complex ankle fusions. Both external and internal fixations have demonstrated positive outcomes with regards to achieving stable fixation and minimizing infection. Recent innovations in the application of biophysical agents and devices have shown promising results as adjuncts for healing. Both osteoconductive and osteoinductive agents have been effectively utilized as biological adjuncts for bone healing with low complication rates. Devices such as pulsed electromagnetic field bone stimulators, internal direct current stimulators and low-intensity pulsed ultrasound bone stimulators have been associated with faster bone healing and improved outcomes scores when compared with controls. The aim of this review article is to present a comprehensive approach to the management of complex ankle fusions, including the use of biophysical adjuncts for healing and a proposed algorithm for their treatment.

Effects of Ankle Arthrodesis on Biomechanical Performance of the Entire Foot

Background/Methodology

Ankle arthrodesis is one popular surgical treatment for ankle arthritis, chronic instability, and degenerative deformity. However, complications such as foot pain, joint arthritis, and bone fracture may cause patients to suffer other problems. Understanding the internal biomechanics of the foot is critical for assessing the effectiveness of ankle arthrodesis and provides a baseline for the surgical plan. This study aimed to understand the biomechanical effects of ankle arthrodesis on the entire foot and ankle using finite element analyses. A three-dimensional finite element model of the foot and ankle, involving 28 bones, 103 ligaments, the plantar fascia, major muscle groups, and encapsulated soft tissue, was developed and validated. The biomechanical performances of a normal foot and a foot with ankle arthrodesis were compared at three gait instants, first-peak, mid-stance, and second-peak.

Principal Findings/Conclusions

Changes in plantar pressure distribution, joint contact pressure and forces, von Mises stress on bone and foot deformation were predicted. Compared with those in the normal foot, the peak plantar pressure was increased and the center of pressure moved anteriorly in the foot with ankle arthrodesis. The talonavicular joint and joints of the first to third rays in the hind- and mid-foot bore the majority of the loading and sustained substantially increased loading after ankle arthrodesis. An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray. The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes. Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery. These variations can provide indications for outcome assessment of ankle arthrodesis surgery.

Calcaneal "Z" osteotomy effect on hindfoot varus after triple arthrodesis in a cadaver model

BACKGROUND

Triple arthrodesis involves subtalar, talonavicular, and calcaneocuboid joint fusion and is performed to relieve pain and correct deformity. Complications include malunion resulting in equinovarus and lateral column overload, which can lead to painful callosities and stress fractures. This study quantified the effectiveness of a closing-wedge calcaneal "Z" osteotomy for correction of the varus condition and reduction of abnormal loading of the lateral border of the foot.

METHODS

Ten fresh-frozen feet were used. Angle meters were attached to the calcaneus and second cuneiform to measure hindfoot and midfoot varus, and pressure sensors were placed under the first and fifth metatarsal heads to document loading of the borders of the foot. Tensile loads were applied to ten extrinsic tendons and the Achilles tendon while an 1187 N axial foot load was applied. Calcaneus and second cuneiform coronal plane angles and medial and lateral plantar pressures were measured initially, after triple fusion-induced varus, and after "Z" osteotomy.

RESULTS

The calcaneal "Z" osteotomy had no significant corrective effect, with hindfoot alignment virtually identical before and after the procedure under the described foot loading conditions. Similarly, second cuneiform inclination, representative of midfoot alignment, showed no change from the osteotomy. Medial and lateral peak plantar pressures after calcaneal "Z" osteotomy did not differ from those measured after varus triple fusion.

CONCLUSION

In this cadaver model of varus malunited triple arthrodesis, the closing-wedge calcaneal "Z" osteotomy was ineffective for correction of bone alignment and lateral forefoot overloading under the tested conditions.

CLINICAL RELEVANCE

The results provide additional information on which to base treatment after triple arthrodesis with varus malunion.

A biomechanical comparison of internal fixation techniques for ankle arthrodesis

The purpose of the present study was to compare the primary bending stiffness characteristics of 5 different ankle arthrodesis fixation techniques: 3 compression screws, an anterior locking plate, a lateral locking plate, an anterior locking plate with a compression screw, and a lateral locking plate with a compression screw. A total of 25 full-scale anatomic models consisting of fourth-generation composite tibiae and tali were tested using an Instron 4505 Universal Testing System. We hypothesized that the use of a compression screw with a locking plate would add considerable stiffness to the fixation construct compared with the use of a locking plate alone. The data have shown that an anterior or lateral plate with a compression screw provides significantly greater stiffness than both a plate and 3 compression screws used individually. No significant difference was seen between the anterior plate with a compression screw and the lateral plate with a compression screw. No significant differences were found among the use of an anterior plate, a lateral plate, or 3 compression screws. We have concluded that when using a locking plate in an anterior or lateral configuration, the addition of a compression screw will considerably increase the primary bending stiffness of ankle arthrodesis.

End-stage hindfoot arthrosis: outcomes of tibiocalcaneal fusion using internal and Ilizarov fixation

End-stage post-traumatic pantalar arthrosis from ankle, pilon, and talus fractures has often been complicated by infection, bone loss, and a soft tissue deficit. Patients can present with neuropathy, diabetes, tobacco use, and previously failed arthrodesis. Fusion in this population has been challenging, with nonunion rates up to 30%, often leading to amputation. We reviewed the results of a standardized protocol that combined simultaneous internal fixation with the Ilizarov technique to achieve fusion in high-risk patients. With institutional review board approval, a retrospective review of the patients treated with simultaneous internal fixation and an Ilizarov frame was undertaken. The records and radiographs allowed identification of the comorbidities and the presence or absence of successful fusion. Complications were acknowledged and treated. Fifteen patients had undergone the procedure. The mean follow-up period was 27.9 (range 9 to 67) months. Thirteen patients (86.67%) had had previous fusion failure. Twelve patients (80%) had developed post-traumatic arthrosis, 5 (33.33%) of whom had open injuries. All patients had 1 comorbidity, and 10 (66.67%) had multiple, including rheumatoid arthritis, diabetes (types 1 and 2), and smoking. Four patients (26.67%) presented with deep infection and bone loss. Union was achieved in 11 (73.33%), with 12 (80%) patients experiencing profound pain relief. Seven patients (46.67%) required symptomatic hardware removal. Three patients (20%) eventually underwent below-the-knee amputation for recalcitrant nonunion. Statistically significant correlations were found between smoking and wound infection and revision and between nonunion and amputation. Our results have indicated that combined internal fixation with Ilizarov application can provide a strong surgical option for the management of end-stage, pantalar arthritis. More studies are needed to compare the cohort outcomes and gait analysis in these patients with those who have chosen below-the-knee amputation.

Tibiocalcaneal arthrodesis using a simple external fixator

Tibiocalcaneal arthrodesis has been a salvage option for conditions with extensive loss of the talar body. In conditions that preclude the use of internal fixation, external compression arthrodesis has been the preferred technique to achieve fusion about the hindfoot. Since Sir John Charnley elucidated the technique of compression arthrodesis using compression clamps, various modifications and techniques of external compression arthrodesis have been described. Various clinical and biomechanical studies have established the superiority of triangular transfixation in external compression arthrodesis. We have described a simple technique of compression arthrodesis after the principle of triangular transfixation using easily available hardware from Ilizarov instrumentation. This technique is relatively inexpensive in terms of the cost of the materials, uses a modular construct, and allows multiplanar correction of the hindfoot. It can be used intraoperatively to distract the hindfoot joints, especially in the presence of fibrosis and poor skin conditions. We believe this device can be a reasonable alternative to the conventional external fixation techniques for tibiocalcaneal arthrodesis.

Biomechanical assessment of flexible flatfoot correction: comparison of techniques in a cadaver model

BACKGROUND

Options for surgical correction of acquired flexible flatfoot deformity involve bone and soft-tissue reconstruction. We used an advanced cadaver model to evaluate the ability of key surgical procedures to correct the deformity and to resist subsequent loss of correction.

METHODS

Stage-IIB flatfoot deformity was created in ten cadaver feet through ligament sectioning and repetitive loading. Six corrective procedures were evaluated: (1) lateral column lengthening, (2) medial displacement calcaneal osteotomy with flexor digitorum longus transfer, (3) Treatment 2 plus lateral column lengthening, (4) Treatment 3 plus "pants-over-vest" spring ligament repair, (5) Treatment 3 plus spring ligament repair with use of the distal posterior tibialis stump, and (6) Treatment 3 plus spring ligament repair with suture and anchor. Correction of metatarsal dorsiflexion and of navicular eversion were quantified initially and periodically during postoperative cyclic loading.

RESULTS

Metatarsal dorsiflexion induced by arch flattening was initially corrected by 5.5° to 10.6°, depending on the procedure. Navicular eversion was initially reduced by 2.1° to 7.7°. The correction afforded by Treatments 1, 3, 4, 5, and 6 exceeded that of Treatment 2 initially and throughout postoperative loading. Inclusion of spring ligament repair did not significantly enhance correction.

CONCLUSIONS

Under the tested conditions, medial displacement calcaneal osteotomy with flexor digitorum longus tendon transfer was inferior to the other evaluated treatments for stage-IIB deformity. Procedures incorporating lateral column lengthening provided the most sagittal and coronal midfoot deformity correction. Addition of spring ligament repair to a combination of these three procedures did not substantially improve correction.

CLINICAL RELEVANCE

An understanding of treatment effectiveness is essential for optimizing operative management of symptomatic flatfoot deformity. This study provides empirical evidence of the advantage of lateral column lengthening and novel information on resistance to postoperative loss of correction.

A biomechanical analysis of two anterior ankle arthrodesis systems

BACKGROUND

An increasingly popular ankle fusion method uses plates and screws positioned on the anterior aspect of the tibiotalar joint. This study compared the mechanical properties of 2 contemporary plate systems for ankle arthrodesis, one based on a single anterior plate and the other comprising paired anteromedial and anterolateral plates.

METHODS

Ten matched pairs of fresh-frozen cadaver ankle joints underwent arthrodesis with a single anatomically contoured anterior plate or 2 anatomic plates applied anteromedially and anterolaterally. Each arthrodesed specimen was subjected to controlled sagittal and coronal plane bending and internal and external rotation. Tibiotalar joint bending stiffness, bending angulation, torsional stiffness, and joint rotation were documented.

RESULTS

Bending stiffness of the 2-plate system was 1.5 to 5 times greater than that of the single-plate system in plantarflexion, dorsiflexion, eversion, and inversion (P = .005-.050). Angulation in each bending direction was several-fold greater than for the single plate (P = .005-.014) at the peak applied moment. Torsional stiffness of the 2-plate system nearly doubled that of the single plate in both rotation directions (P = .014, P = .005). Approximately half as much arthrodesis site rotation occurred with 2-plate fixation at the peak applied torque (P = .005, P = .007).

CONCLUSION

The tested 2-plate arthrodesis system has the potential to optimize arthrodesis site stiffness compared with fixation with a contemporary single plate.

CLINICAL RELEVANCE

Use of the stiffer 2-plate system could improve the clinical fusion rate, especially in patients with suboptimal bone quality.

Benchtop comparison of a novel dynamic compression screw to a standard cortical screw: compression integrity and gap size over time during simulated resorption

Literature reports the incidence of failed isolated foot and ankle fusions as up to 23%. A contributing factor is the natural bone resorption, which occurs resulting in loss of compression and gapping at the fusion site when standard static compression plates and screws are used. However, an innovative dynamic compression screw may provide lasting compression despite resorption. This benchtop study shows that the FxDEVICES spring-loaded dynamic POGO screw maintains more compression and more consistent compression rate during simulated resorption, as compared with a standard compression screw. The novel screw maintained much greater compression strength within the first millimeter of simulated resorption (13.57 vs 4.38 lb) and maintained greater compression strength at the test completion (1.14 vs 0 lb). The novel screw revealed a more consistent resorption rate over the duration of the simulation. Clinically, this may result in more stability and improved fusion rates.

Tibiotalar arthrodesis in posttraumatic arthritis using the tension band technique

BACKGROUND

Although a variety of surgical techniques are available for the treatment of ankle degenerative disease, arthrodesis is a common treatment especially for unilateral posttraumatic arthritis in young patients. A clear trend toward internal fixation for ankle arthrodesis is evident, but fusion site compression is known to play an integral role in primary bone healing.

METHODS

Between September 2001 and October 2009, 17 adults with painful end-stage posttraumatic ankle arthritis were treated with the tension band technique to achieve tibiotalar arthrodesis.

RESULTS

Tibiotalar fusion was obtained in all patients at a mean of 16.6 (range, 13 to 28) weeks. No patient had pain at the last postoperative follow-up examination. AOFAS and Mazur scores were preoperatively 29 and 23.1, respectively, and postoperatively 71.1 and 70.7, respectively.

CONCLUSION

Arthrodesis with a tension band was a safe and effective surgical treatment option for posttraumatic ankle arthritis in patients without infection and good bone density, as it was simple, less invasive, and inexpensive and allowed early full weight-bearing.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Talar neck fracture after tibiotalar arthrodesis: case report

Level of Evidence: V, Expert Opinion

Ankle fusion stability: a biomechanical comparison of external versus internal fixation

This biomechanical study compares bimalleolar external fixation to conventional crossed-screw construct in terms of stability and compression for ankle arthrodesis. The goals of the study were to determine which construct is more stable with bending and torsional forces, and to determine which construct achieves more compression.Fourth-generation bone composite tibia and talocalcaneal models were made to 50th percentile anatomic specifications. Fourteen ankle fusion constructs were created with bimalleolar external fixators and 14 with crossed-screw constructs. Ultimate bend, torque, and compression testing were completed on the external fixator and crossed-screw constructs using a multidirectional Materials Testing Machine (MTS Systems Corp, Eden Prairie, Minnesota). Ultimate bend testing revealed a statistically significant difference (P=.0022) with the mean peak load to failure for the external fixator constructs of 973.2 N compared to 612.5 N for the crossed-screw constructs. Ultimate torque testing revealed the mean peak torque to failure for the external fixator construct was 80.2 Nm and 28.1 Nm for the crossed-screw construct, also a statistically significant difference (P=.0001). The compression testing yielded no statistically significant difference (P=.9268) between the average failure force of the external fixator construct (81.6 kg) and the crossed-screw construct (81.2 kg).With increased stiffness in both bending and torsion and comparable compressive strengths, bimalleolar external fixation is an excellent option for tibiotalar ankle arthrodesis.

Treatment of ankle osteoarthritis: arthrodesis versus total ankle replacement

While ankle arthrodesis has remained the gold standard treatment for symptomatic primary, secondary, and posttraumatic ankle arthritis, more recently, total ankle replacement (TAR) has seen considerable improvement in terms of biomechanics, function, and complication rates. However, while in the long-term degeneration of the adjacent joints is almost always found on radiographs after ankle arthrodesis, the longevity of TAR is still insufficient and does not match that of total knee and hip joints. The current review article focuses on the treatment of ankle arthritis by means of arthrodesis and TAR.

Surgery on the rheumatoid ankle joint: efficacy versus effectiveness

This article examines synovectomy and ankle arthrodesis for the rheumatoid ankle joint. Reviews of osteoimmunology and gait analyses specific to rheumatoid arthritis are included. Comparison studies including ankle arthrodesis and total ankle arthroplasty are reviewed.