How Does a Novel In Situ Fixed-bearing Implant Design Perform in Revision Ankle Arthroplasty in the Short Term? A Survival, Clinical, and Radiologic Analysis.

BACKGROUND: Given the growing number of primary total ankle replacements (TAR), an increase in the number of patients undergoing subsequent revisions might be expected. Achieving a stable and balanced ankle while preserving the remaining bone stock as much as possible is crucial for success in revision TAR. Most reported techniques rely on bulky implants with extended fixation features. Since 2018, we have used a novel, three-component ankle prosthesis for revision that is converted in situ to a fixed-bearing, two-component ankle prosthesis once the components have found their position according to an individual's anatomy. The results of this novel concept (fixation, revision, pain, or function) have not, to our knowledge, been reported. QUESTIONS/PURPOSES: What are the short-term results with this new revision TAR design, in terms of (1) repeat revision surgery, (2) patient-reported outcomes on the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, (3) pain according to the VAS, and (4) radiographic signs of fixation? METHODS: Between February 2018 and February 2020, we performed 230 TAR surgeries (in 206 patients) for any indication in our clinic. The novel semiconstrained, uncemented Hintermann Series H2 © implant was used in 96% (220 of 230) of procedures (201 patients). Fifty-four percent (119 of 220) of these were converted from an existing TAR to H2, which was the focus of the present study. However, only 45% (54 of 119) of these conversions to H2 were eligible for analysis. These patients had a mean age of 63 ± 12 years, and 43% (23 of 54) were women. The median (range) follow-up time was 3.2 years (2.0 to 4.3). The H2 design allows in situ conversion to a fixed-bearing system, with minimal bone resection. It achieves translational and rotational stability while preserving function and supporting the periarticular soft tissues. We defined repeat revision as exchange of one or both metal components, ankle fusion, or amputation and assessed it using a cumulative incidence survivorship estimator. Factors potentially associated with revision were assessed using Cox regression analyses. Clinical and radiologic outcomes were assessed preoperatively and at the most recent follow-up interval. Clinical outcomes included pain on the VAS (average pain during normal daily activity during the past seven days) and AOFAS score. Radiologic outcomes were the tibial articular surface angle, tibiotalar surface angle, talar tilt angle in the coronal plane, and AP offset ratio in the sagittal plane, as well as radiolucent lines and radiographic signs of loosening, defined as change in position greater than 2° of the flat base of the tibia component in relation to the long axis of the tibia, subsidence of the talar component into the talus greater than 5 mm, or change in position greater than 5° relative to a line drawn from the top of the talonavicular joint to the tuberosity of the calcaneus, as seen on plain weightbearing radiographs. RESULTS: The cumulative incidence of repeat revision after 1 and 2 years was 5.6% (95% CI 0% to 11%) and 7.4% (95% CI 0% to 14%), respectively. With the numbers available, no clinical factors we analyzed were associated with the risk of repeat revision. The median values of all assessed clinical outcomes improved; however, not all patients improved by clinically important margins. The median (range) AOFAS ankle-hindfoot score increased (from 50 [16 to 94] to 78 [19 to 100], difference of medians 28; p < 0.01), and the median pain on the VAS decreased (from 5 [0 to 9] to 2 [0 to 9], difference of medians 3; p < 0.01) from before surgery to follow-up at a minimum of 2 years. Radiographically, lucency was seen in 12% (6 of 49 patients) and loosening was seen in 8% (4 of 49). One of these patients showed symptomatic loosening and was among the four patients overall who underwent revision. We could not assess risk factors for repeat revision because of the low number of events (four). CONCLUSION: The investigated new in situ fixed-bearing ankle design achieved overall better short-term results than those reported in previous research. Destabilization of the ankle joint complex, soft tissue insufficiency, and possible changes of the joint configuration need an optimal solution in revision arthroplasty. The studied implant might be the answer to this complex issue and help surgeons in the perioperative decision-making process. However, a relatively high percentage of patients did not achieve a clinically important difference. Observational studies are needed to understand long-term implant behavior and possibly to identify ankles benefiting the most from revision. LEVEL OF EVIDENCE: Level IV, therapeutic study.

The impact of COVID-19 on mobility choices in Switzerland.

We study the effect of the COVID-19 pandemic and the associated government measures on individual mobility choices in Switzerland. Our data is based on over 1,600 people for which we observe all trips during eight weeks before the pandemic and until May 2021. We find an overall reduction of travel distances by 60 percent, followed by a gradual recovery during the subsequent re-opening of the economy. Whereas driving distances have almost completely recovered, public transport re-mains under-used. The introduction of a requirement to wear a mask in public transport had no measurable impact on ridership. The individual travel response to the pandemic varies along socio-economic dimensions such as education and house-hold size, with mobility tool ownership, and with personal values and lifestyles. We find no evidence for a significant substitution of leisure travel to compensate for the reduction in work-related travel.

Effect of total ankle replacement on the 3-dimensional subtalar joint alignment in varus ankle osteoarthritis.

BACKGROUND: Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar alignment. METHODS: Fourteen patients (15 ankles, mean age 61 ± 6 years) who underwent TAR for varus ankle OA were analyzed using semi-automated measurements based on weight-bearing computed tomography. Twenty healthy individuals served as a control group. RESULTS: All angles improved between preoperative and a minimum of 1 year (mean 2.1 years) postoperative and were statistically significant in 6 out of 8 angles (P < 0.05). CONCLUSIONS: Our findings indicate that talus repositioning after TAR restores the subtalar joint alignment which may improve hindfoot biomechanics. Future studies are required to implement these findings for TAR in presence of hindfoot deformity. LEVEL OF EVIDENCE: IV.

What Are the Indications for Implant Revision in Three-component Total Ankle Arthroplasty?

BACKGROUND: Given the increasing usage of total ankle arthroplasty (TAA), a better understanding of the reasons leading to implant revision and the factors that might influence those indications is necessary to identify at-risk patients. QUESTION/PURPOSES: Using a single-design three-component ankle prosthesis, we asked: (1) What is the cumulative incidence of implant revision at 5 and 10 years? (2) What are the indications for implant revision in our population? (3) What factors are associated with an increased likelihood of implant revision during the time frame in question? METHODS: Between 2003 and 2017, primary TAA using a single-design three-component ankle implant was performed by or under the supervision of the implant designer in 1006 patients (1074 ankles) aged between 17 and 88 years to treat end-stage ankle osteoarthritis. No other TAA systems were used during the study period at the investigators' institution. In 68 patients with bilateral surgery, only the first TAA was considered. Of the patients treated with the study implant, 2% (16 of 1006) were lost to follow-up 5 to 14 years after TAA and were not known to have died or undergone revision, and 5% (55 of 1006) were deceased due to reasons unrelated to the procedure, leaving 935 patients for evaluation in this retrospective study. The mean (range) follow-up for the included patients was 8.8 ± 4.2 (0.2 to 16.8) years. Implant revision was performed 0.5 to 13.2 years after TAA in 12% (121 of 1006) of our patients. Survivorship free from revision was calculated using cumulative incidence (competing risks) survivorship, with death as a competing risk. The reason for each revision was classified into one of six categories according to a modified version of a previously published protocol: aseptic loosening, cyst formation, instability, deep infection, technical error, and pain without another cause. Two foot and ankle surgeons reviewed the records of all patients who underwent implant revision and assigned each patient's reason for revision to one of the six categories. The decision for assigning each patient to one of the six categories was made based on a consensus agreement. A subgroup classification of preoperative ankle alignment (neutral, mild, and major deformity) and variables of age, sex, BMI, etiology of ankle osteoarthritis, and number of preoperative and intraoperative hindfoot or midfoot procedures were used in a multinomial logistic regression and Cox regression analysis to estimate their association with reason for revision and implant survival until revision. RESULTS: The cumulative incidence of implant revision at the mean (range) follow-up time of 8.8 ± 4.2 years (0.2 to 16.8) was 9.8% (95% confidence interval 7.7% to 11.8%). Five and 10 years after TAA, cumulative incidence was 4.8% (95% CI 3.4 to 6.1) and 12.1% (95% CI 9.7% to 14.5%), respectively. The most common reason for revision was instability (34% [41 of 121]), followed by aseptic loosening of one or more metallic components (28% [34 of 121]), pain without another cause (12% [14 of 121]), cyst formation (10% [12 of 121]), deep infection (9% [11 of 121]), and technical error (7% [9 of 121]). Ankles with a major hindfoot deformity before TAA were more likely to undergo revision than ankles with a minor deformity (hazard ratio 1.9 [95% CI 1.2 to 3.0]; p = 0.007) or neutral alignment (HR 2.5 [95% CI 1.5 to 4.4]; p = 0.001). A preoperative hindfoot valgus deformity increased revision probability compared with a varus deformity (HR 2.1 [95% CI 1.4 to 3.4]; p = 0.001). CONCLUSION: Instability was a more common reason for implant revision after TAA with this three-component design than previously reported. All causes inducing either a varus or valgus hindfoot deformity must be meticulously addressed during TAA to prevent revision of this implant. Future studies from surgeons/institutions not involved in this implant design are needed to confirm these findings and to further investigate why a substantial number of patients had pain of unknown cause prompting revision. LEVEL OF EVIDENCE: Level III, therapeutic study.

Mid- to long-term outcome in patients treated with a mini-open sinus-tarsi approach for calcaneal fractures.

BACKGROUND: While the extended lateral approach was the gold standard for treatment of calcaneal fractures for decades, the mini-open approach through the sinus tarsi gained popularity in recent years. Although widely used, there are only a few reports available in the literature reporting on mid- to long-term results. Therefore, the purpose of the study was to report on mid- to long-term radiographic and clinical outcomes of calcaneal fractures treated surgically using a mini-open sinus tarsi approach. MATERIALS AND METHODS: In this retrospective review, radiographic and clinical outcome measures of 30 consecutive patients (34 fractures) were analyzed. Conventional radiographs were used to measure the Boehler's angle before and after surgical fixation. Computed tomography (CT) scans were analyzed to distinguish between joint depression and tongue-type calcaneal fractures. Each calcaneal fracture was additionally categorized according to the Sanders classification. The clinical outcome was measured using a 5-point Likert scale ranging from 0 (very unsatisfied) to 4 (very satisfied), the Visual Analog Scale (VAS) for pain, and the Maryland Foot Score. RESULTS: The Boehler's angle improved from 12.6 degrees preoperatively to 26.3 degrees postoperatively (P < 0.001). Loss of sagittal reduction (i.e., a decline of the Boehler's angle of > 5 degrees) from postoperative to the last follow-up was evident in nine (26%) fractures. Out of 29 patients with an available satisfaction score, 20 (69%) were very satisfied, 8 (28%) were satisfied, and one (3%) was moderately satisfied. Satisfaction at the last follow-up declined with higher age at surgery. An overall low complication rate was evident, with painful hardware needing removal being the most common complication. CONCLUSIONS: Approaching calcaneus fractures through the sinus tarsi provides satisfactory mid- to long-term radiographic and clinical outcomes, independent of the severity of the fractures according to the Sanders classification. LEVEL OF EVIDENCE: Level IV, Retrospective Case Series.

Observed impacts of the Covid-19 first wave on travel behaviour in Switzerland based on a large GPS panel.

In Switzerland, strict measures as a response to the Covid-19 pandemic were imposed on March 16, 2020, before being gradually relaxed from May 11 onwards. We report the impact of these measures on mobility behaviour based on a GPS tracking panel of 1439 Swiss residents. The participants were also exposed to online questionnaires. The impact of both the lockdown and the relaxation of the measures up until the middle of August 2020 are presented. Reductions of around 60% in the average daily distance were observed, with decreases of over 90% for public transport. Cycling increased in mode share drastically. Behavioural shifts can even be observed in response to the announcement of the measures and relaxation, a week before they came in to place. Long-term implications for policy are discussed, in particular the increased preference for cycling as a result of the pandemic.

Supramalleolar osteotomy in post-traumatic valgus ankle osteoarthritis.

PURPOSE: To assess how the level of the deformity, the stage of the osteoarthritic process, and the role of additional surgeries impact radiographic and clinical outcomes following an extra-articular medial closing supramalleolar osteotomy for treatment of post-traumatic valgus ankle osteoarthritis. METHODS: About 56 consecutive patients who underwent an extra-articular medial closing wedge osteotomy for post-traumatic valgus ankle osteoarthritis were retrospectively analyzed. Subgroups were formed according to the pre-operative level of deformity and preoperative stage of ankle osteoarthritis. Additional surgical steps required to achieve a properly balanced hindfoot were also noted. Radiographic and clinical outcomes of each subgroup were compared with each other, and the role of additional surgical steps required to achieve a balanced hindfoot was investigated. RESULTS: Radiographic and clinical outcomes improved significantly between pre-operative assessment and the last follow-up. Patients with a pre-operative supramalleolar deformity showed superior radiographic outcomes compared to patients with an intra-articular deformity. Clinical outcomes did not differ significantly between these two subgroups. The pre-operative stage of ankle osteoarthritis significantly impacted radiographic outcomes but did not influence clinical outcome measures. An additional fibula or calcaneus osteotomy was necessary for 55% and 23% of all patients, respectively. CONCLUSION: Extra-articular medial closing supramalleolar osteotomies show satisfactory mid- to long-term radiographic and clinical outcomes in patients with post-traumatic valgus ankle osteoarthritis.

Hindfoot balancing in total ankle replacement: the role of supramalleolar osteotomies.

PURPOSE: To compare the obtained deformity correction and clinical/functional outcomes between patients who underwent total ankle replacement (TAR) with or without a concurrent supramalleolar osteotomy (SMO) to address a varus and/or recurvatum deformity of the distal tibia. METHODS: Data of 23 patients treated with an additional SMO to correct a varus and/or recurvatum deformity of the distal tibia at the time of TAR were prospectively collected. Twenty-three matched patients who underwent TAR only served as controls. RESULTS: The American Orthopaedic Foot and Ankle Society (AOFAS)-hindfoot scale and pain assessed on a Visual Analogue Scale (VAS) did not significantly differ between the two groups at the final follow-up (AOFAS-hindfoot scale SMO/TAR group = 82 ± 10; TAR group = 82 ± 12; VAS pain SMO/TAR group = 1 (range, 0-4); TAR group = 1 (range, 0-5)). Ankle range of motion (ROM) did not improve in the SMO/TAR group (pre-operative = 27 ± 13 degrees, last follow-up = 30 ± 9 degrees; P = .294), but did improve in the TAR group (pre-operative = 31 ± 14 degrees, last follow-up = 39 ± 14 degrees; P = .049). Two patients who underwent SMO/TAR showed non-union of the tibial osteotomy, and two patients who underwent TAR only suffered from an intra-operative medial malleolar fracture. CONCLUSION: An additional SMO during TAR in patients with a varus and/or recurvatum deformity of the distal tibia is not beneficial in most cases and should only be considered in pronounced multiplanar deformities.

Impact of the rotational position of the hindfoot on measurements assessing the integrity of the distal tibio-fibular syndesmosis.

BACKGROUND: Approximately 20% of patients with ankle fractures demonstrate evidence of syndesmotic injuries. As intra-operative measurements have high specifity but low sensitivity for identifying injuries to the distal tibio-fibular syndesmosis, numerous measurements have been developed to assess pre-operative syndesmosis integrity. Several factors affecting measurements on conventional radiographs and computed tomography (CT) images have been identified. The influence of the rotational position of the hindfoot during imaging, however, remains unclear. METHODS: Twenty (20) healthy volunteers (mean age 49, standard deviation [SD] 7.5, range 40-66 years) underwent a weightbearing cone beam CT scan. From this dataset, digitally reconstructed radiographs (DRRs) and axial CT images of the hindfoot were reconstructed. For each image, an antero-posterior view (defined as a plane perpendicular to the longitudinal axis of the second metatarsal) was reconstructed. Then, internal and external rotation of the hindfoot was simulated in 10° increments (maximum rotation of 30°). The tibio-fibular clear space (TFCS), tibio-fibular overlap (TFO), and medial clear space (MCS) were measured on each reconstructed DRR and axial CT image. RESULTS: Internal rotation of the hindfoot substantially impacted inter-observer agreement for TFCS measurements on DRRs. Intra- und inter-observer agreement of measurements (MCS, TFCS, TFO) on axial CT images was minimally affected by hindfoot rotation. Hindfoot rotation highly impacted on absolute values of each measurement. As little as 10° of internal or external rotation significantly (P<0.05) impacted MCS and TFO measurements (DRRs and axial CT images). External rotation increased, while internal rotation decreased, MCS and TFO measurements. TFCS measurements performed on DRRs did not significantly differ for 10° (P=0.0931) and 20° (P=0.486) of external rotation or for 10° of internal (P=0.33) rotation. DISCUSSION: The rotational position of the hindfoot during imaging has a major impact on MCS, TFCS, and TFO measurements when using DRRs and axial CT images. To avoid misinterpretation of measurements, the position of the hindfoot during imaging must be standardized. CONCLUSIONS: DRRs and axial CT images require reliable reconstructions to allow accurate assessment of the TFCS, TFO, and MCS.

Is load application necessary when using computed tomography scans to diagnose syndesmotic injuries? A cadaver study.

BACKGROUND: Injuries to the distal tibio-fibular ligaments are common. While pronounced injuries can be reliably diagnosed using conventional radiographs, assessment of subtle syndesmotic injuries is challenging. This cadaver study determines the impact of loading on the assessment of incomplete and more complete syndesmotic injuries when using weightbearing computed tomography (CT) scans. METHODS: Fourteen paired male cadavers (tibial plateau to toe-tip) were included. A radiolucent frame held specimens in a plantigrade position while both non-weightbearing and weightbearing computed tomography (CT) scans were taken. The following conditions were tested: First, intact ankles (Native) were scanned. Second, one specimen from each pair underwent anterior inferior tibio-fibular ligament (AITFL) transection (Condition 1A), while the contralateral underwent deltoid transection (Condition 1B). Third, the remaining intact deltoid or AITFL was transected from each specimen (Condition 2). Finally, the distal tibiofibular interosseous membrane (IOM) was transected in all ankles (Condition 3). Eight different measurements were performed to assess the integrity of the distal tibio-fibular syndesmosis on axial CT scans. RESULTS: Load application had no impact on most measurements. While incomplete syndesmotic injuries could not be identified, cadavers with more complete injuries differentiated from native ankles when assessed using axial CT images. No significant difference was evident between discrete AITFL or deltoid ligament transection. CONCLUSIONS: In a cadaver model, load application had no effect on the assessment of the distal tibio-fibular syndesmosis in incomplete and more complete syndesmotic injuries. Only more complete injuries of the distal tibio-fibular syndesmosis could be identified using axial CT images.

Influence of the ankle position and X-ray beam angulation on the projection of the posterior facet of the subtalar joint.

OBJECTIVE: Using digitally reconstructed radiographs (DRRs), we determined how changes in the projection angle influenced the assessment of the subtalar joint. MATERIALS AND METHODS: Weightbearing computed tomography (CT) scans were acquired in 27 healthy individuals. CT scans were segmented and processed to create DRRs of the hindfoot. DRRs were obtained to represent 25 different perspectives to simulate internal rotation of the ankle with and without caudal angulation of the X-ray beam. Subtalar joint morphology was quantified by determining the joint space curvature, subtalar inclination angle (SIA), calcaneal slope (CS), and projection of the subtalar joint line on three-dimensional (3-D) reconstructions of the calcaneus. RESULTS: The curvature of the projected joint space was altered substantially over the different DRR projections. Simulated caudal angulation of the X-ray beam with respect to the ankle decreased the SIA and CS significantly. Internal rotation also had a significant impact on the SIA and CS if the X-ray beam was in neutral or in 10° of caudal angulation. An antero-posterior (AP) view of the ankle showed the posterior area of the posterior facet, whereas a more anterior area was visible with internal rotation of the foot and caudal angulation of the X-ray beam. CONCLUSION: Internal rotation of the foot of 20° is recommended to assess the posterior aspect of the posterior facet, whereas a combined 20° internal rotation of the foot and 40° caudal angulation of the X-ray beam is best to assess the anterior aspect of the posterior facet of the subtalar joint.

Currently used imaging options cannot accurately predict subtalar joint instability.

PURPOSE: To give a systematic overview of current diagnostic imaging options and surgical treatment for chronic subtalar joint instability. METHODS: A systematic literature search across the following sources was performed: PubMed, ScienceDirect, and SpringerLink. Twenty-three imaging studies and 19 outcome studies were included. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2) tool was used to assess the methodologic quality of the imaging articles, while the modified Coleman Score was used to assess the methodologic quality of the outcome studies. RESULTS: Conventional radiographs were most frequently used to assess chronic subtalar joint instability. Talar tilt, anterior talar translation, and subtalar tilt were the three most commonly used measurement methods. Surgery often included calcaneofibular ligament reconstruction. CONCLUSION: Current imaging options do not reliably predict subtalar joint instability. Distinction between chronic lateral ankle instability and subtalar joint instability remains challenging. Recognition of subtalar joint instability as an identifiable and treatable cause of ankle pain requires vigilant clinical investigation. LEVEL OF EVIDENCE: Systematic Review of Level III and Level IV Studies, Level IV.

Vascularized Bone Autograft for the Treatment of Chondroblastoma of the Talus at Imminent Risk of Joint Breakdown: Three Case Reports.

Surgical treatment options in a chondroblastoma of the talus breaching the subchondral layer with imminent risk of talar collapse in the weightbearing area are limited. A joint-preserving surgery should be advocated. Because current treatment options such as curettage, cryosurgery, or radiofrequency ablation may not be able to prevent a talar dome breakdown in large defects, nonvascularized bone grafting has been advocated to fill the void. To overcome the lack of vitality, a vascularized bone autograft might be an attractive alternative. We present 3 cases where a large talar defect owing to a chondroblastoma was treated with a vascularized bone autograft. In 1 of the cases, a free microvascular iliac crest bone graft was used, whereas in the other 2 cases, a vascularized graft was harvested from the medial femoral condyle. Computed tomographic scans demonstrated a stable incorporation of the graft in all cases. All patients were highly satisfied with the obtained results and showed a clinical functional outcome similar to the contralateral foot after 36, 60, and 72 months. At the latest radiographic follow-up, no evidence of recurrence was observed. In conclusion, a free vascularized bone autograft can be used to treat a large talar defect owing to chondroblastoma in young patients.

Subtalar joint alignment in ankle osteoarthritis.

BACKGROUND: Although it has been proposed that in mid-stage ankle osteoarthritis, the subtalar joint can compensate for deformities above the ankle joint, the evidence is weak. We thus investigated subtalar joint alignment in different stages of ankle osteoarthritis using weightbearing computed tomography (CT) scans. METHODS: The subtalar joint of 88 patients with osteoarthritis of the ankle joint and a control group of 27 healthy volunteers were assessed. Subgroups were performed according to the ankle deformity (varus and valgus) and stage of ankle joint osteoarthritis. Subtalar joint alignment was assessed on weightbearing CT scans. RESULTS: A more valgus subtalar joint alignment was found in patients with varus ankle osteoarthritis. No significant difference of the subtalar joint alignment was evident when comparing different stages of ankle osteoarthritis. CONCLUSIONS: Varus ankles compensate in the subtalar joint for deformities above the ankle joint. Compensation does not correlate with the stage of ankle osteoarthritis.

Surgical outcome in chronic syndesmotic injury: A systematic literature review.

BACKGROUND: Chronic injuries of the distal tibio-fibular syndesmosis often present with non-specific clinical and radiographic findings. If chronic instability to the distal tibio-fibular syndesmosis is verified, various reconstruction options are available. The purpose of this article is to give a systematic review of current surgical treatment options in patients with chronic syndesmotic injury. METHODS: Three major medical databases were searched from inception through December 12, 2017: PubMed, ScienceDirect, and SpringerLink. Studies were included if they were original research studies which assessed the outcome of patients treated surgically for chronic syndesmotic instability. Only studies written in English were considered. The following data were extracted from each study: number of patients and ankles included, average patients' age, gender, study design, preoperative examination, time between the initial injury and the operation, postoperative follow-up time, operative technique, complication rates, and clinical outcome. The modified Coleman Score was used to assess the methodologic quality of the included studies. RESULTS: Seventeen (17) studies were included. All studies were retrospective or prospective case series. Each study was performed at a single center. In general, good functional outcomes and low complication rates were reported. The American Orthopaedic Foot and Ankle (AOFAS) score was most frequently used outcome tool to measure postoperative outcomes. The quality of the included studies was overall satisfactory. CONCLUSIONS: A few studies have reported on the operative outcomes after treating chronic syndesmotic instability. Several different techniques were used to treat this problem. The quality of current studies is overall satisfactory but could be improved with larger patient numbers and prospective analysis. Recognition of this clinical entity as an identifiable and treatable cause of ankle pain requires vigilant clinical investigation. LEVEL OF EVIDENCE: Level IV; Systematic Review of Level IV Studies.

Imaging in syndesmotic injury: a systematic literature review.

OBJECTIVES: To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis. MATERIALS AND METHODS: A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality. RESULTS: The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice. CONCLUSIONS: Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

Bony periosteum-covered iliac crest plug transplantation for severe osteochondral lesions of the talus: a modified mosaicplasty procedure.

PURPOSE: This study reports first evidence of a modified procedure for osteochondral autologous transplantation where bony periosteum-covered plugs are harvested at the iliac crest and transplanted into the talar osteochondral lesion. METHODS: Thirteen out of 14 patients, average age 39.6 (SD 14.4) years, were followed clinically and radiographically for a median of 25 (24-28) months (minimal follow-up, 24 months). RESULTS: For these 13 patients, the American Orthopaedic Foot and Ankle Society hindfoot score increased from 47 (SD 11) points pre-operatively, to 81 (SD 14) points postoperatively (p < 0.0001). The average pain score decreased from 6.6 (SD 1.3) points pre-operatively, to 1.4 (SD 1.9) points postoperatively (p < 0.0001). Seven patients returned to sports activity. Radiographically good plug osteointegration was observed in nine out of 11 ankles. Follow-up arthroscopy showed fibrous cartilage in four ankles, periosteum hypertrophy in five ankles, and partial or total missing of coverage of the bone in three ankles. Three revision surgeries had to be performed. CONCLUSIONS: This modified mosaicplasty might be recommended for severe and recurrent osteochondral lesions of the talus and may lead to restoration of the subchondral bone stock, formation of fibro-cartilage, and stable joint function. LEVEL OF EVIDENCE: IV.

Survival and risk assessment in revision arthroplasty of the ankle.

Aims: Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined. Methods: This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up. Results: The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up. Conclusion: Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved.

Surgical technique: talar neck osteotomy to lengthen the medial column after a malunited talar neck fracture.

BACKGROUND: Treatment of malunited talar neck fractures is challenging, and few studies address anatomic reconstruction as an alternative to arthrodesis. We describe a new surgical approach attempting to improve function and avoid development of degenerative changes in the adjacent joints. DESCRIPTION OF TECHNIQUE: Indications included malunited talar neck fractures. Through a dorsomedial approach, a correcting osteotomy with interposition of an autograft or allograft was performed and internally fixed using buttress plate and/or screws. METHODS: We retrospectively reviewed seven patients in whom the new technique was indicated for malunited talar neck fractures. The mean age of the patients was 42 years (range, 17-60 years). We analyzed the patients clinically and radiographically with a minimum followup of 2.5 years (mean, 4 years; range, 2.5-9.8 years). RESULTS: At followup, all patients experienced substantial pain relief. No development of avascular necrosis or radiographic arthritic changes were observed. Physical categories of the SF-36 score showed great improvements. The American Orthopaedic Foot and Ankle Society hindfoot score increased from 41±19 preoperatively (range, 20-62) to 84±11 (range, 68-97). The average talar-first metatarsal angle increased dramatically. All but one patient showed radiographic union of the talar osteotomy. Implant removal was performed in three patients. CONCLUSIONS: Based on these observations, correctional osteotomy is a reasonable option for treating patients with malunited talar neck fractures by providing a pain-free foot with good function, recreating anatomy, and involving a low risk of postoperative complications. Further studies with longer followups are required to confirm these findings persist with time. LEVEL OF EVIDENCE: Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.