Nicola Krähenbühl

Orientation of the Subtalar Joint Measurement and Reliability Using Weightbearing CT Scans

Background: Up to 60% of patients with an osteoarthritic ankle joint develop talar tilt with progression of the osteoarthritic process. The configuration of the subtalar joint, in particular the posterior facet, may contribute to the development of this wear pattern. Recently, the subtalar vertical angle (SVA) was used to describe the posterior facet of the subtalar joint in the frontal plane. The aim of this work was to analyze if the orientation of the subtalar joint may influence the type of asymmetric ankle osteoarthritis. Methods: In total, 60 ankles were retrospectively analyzed including 40 osteoarthritic patients and 20 healthy controls. The osteoarthritic ankles were divided into 4 groups: varus ankle joints with (incongruent) or without (congruent) a tilted talus and valgus ankle joints with (incongruent) or without (congruent) a tilted talus. The orientation of the subtalar joint was described using the SVA. The SVA was determined for every patient using weightbearing CT scans. Additionally, the inter- and intraobserver reliability was assessed using intraclass correlation coefficients (ICCs). Results: The inter- and intraobserver reliability was excellent (ICC > 0.989 and >0.975, respectively). The varus groups (incongruent and congruent) had significantly lower SVA values, that is, more varus orientation of the subtalar joint than the valgus groups (P < .05). The SVA of the control group was between the values of the varus and valgus ankles. Conclusion: The SVA provided a reliable and consistent method to assess the varus/valgus configuration of the posterior facet of the subtalar joint. In our cohort, varus osteoarthritis of the ankle joint occurred with varus orientation of the subtalar joint whereas in patients with valgus osteoarthritis, valgus orientation of the subtalar joint was found. Our data suggest that the subtalar joint orientation may be a risk factor for the development of ankle joint osteoarthritis. Level of Evidence: Level III, retrospective case control study.

Mid- to Long-term Results of Supramalleolar Osteotomy

Background: Good clinical and radiographic short-term results have been reported for patients who underwent realignment surgery of the hindfoot for treatment of early- and mid-stage ankle osteoarthrosis (OA). However, no mid- to long-term results have been reported. The aim of this study was to gain a better insight into the indications and contraindications for realignment surgery. Methods: Two hundred ninety-four patients (298 ankles) underwent realignment surgery between December 1999 and June 2013. Kaplan-Meier survival analysis was performed with total ankle replacement and arthrodesis of the ankle joint as endpoints. A Cox proportional hazards model was performed to identify risk factors for failure. The mean time to follow-up was 5.0 ± 3.7 years. Results: The overall 5-year survival rate was 88%. Thirty-eight patients (12.9%) underwent either secondary total ankle replacement or ankle arthrodesis (30 total ankle replacements, 8 ankle arthrodesis). Risk factors for failure following realignment surgery were age at the time of surgery and a Takakura score of 3b preoperatively. Conclusion: Realignment surgery of the hindfoot was an excellent treatment option for young and physically active patients with early to mid-stage ankle OA. Level of Evidence: Level IV, prospective observational study.

Imaging in syndesmotic injury: a systematic literature review

ObjectivesTo give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis.Materials and methodsA 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.ResultsThe 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.ConclusionsConventional 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.

The subtalar joint: A complex mechanism

Subtalar joint anatomy is complex and can vary significantly between individuals. Movement is affected by several adjacent joints, ligaments and periarticular tendons. The subtalar joint has gained interest from foot and ankle surgeons in recent years, but its importance in hindfoot disorders is still under debate. The purpose of this article is to give a general overview of the anatomy, biomechanics and radiographic assessment of the subtalar joint. The influence of the subtalar joint on the evolution of ankle joint osteoarthritis is additionally discussed. Cite this article: EFORT Open Rev 2017;2:309-316. DOI: 10.1302/2058-5241.2.160050

Orientation of the Subtalar Joint

Background: Up to 60% of patients with an osteoarthritic ankle joint develop talar tilt with progression of the osteoarthritic process. The configuration of the subtalar joint, in particular the posterior facet, may contribute to the development of this wear pattern. Recently, the subtalar vertical angle (SVA) was used to describe the posterior facet of the subtalar joint in the frontal plane. The aim of this work was to analyze if the orientation of the subtalar joint may influence the type of asymmetric ankle osteoarthritis. Methods: In total, 60 ankles were retrospectively analyzed including 40 osteoarthritic patients and 20 healthy controls. The osteoarthritic ankles were divided into 4 groups: varus ankle joints with (incongruent) or without (congruent) a tilted talus and valgus ankle joints with (incongruent) or without (congruent) a tilted talus. The orientation of the subtalar joint was described using the SVA. The SVA was determined for every patient using weightbearing CT scans. Additionally, the inter- and intraobserver reliability was assessed using intraclass correlation coefficients (ICCs). Results: The inter- and intraobserver reliability was excellent (ICC > 0.989 and >0.975, respectively). The varus groups (incongruent and congruent) had significantly lower SVA values, that is, more varus orientation of the subtalar joint than the valgus groups (P < .05). The SVA of the control group was between the values of the varus and valgus ankles. Conclusion: The SVA provided a reliable and consistent method to assess the varus/valgus configuration of the posterior facet of the subtalar joint. In our cohort, varus osteoarthritis of the ankle joint occurred with varus orientation of the subtalar joint whereas in patients with valgus osteoarthritis, valgus orientation of the subtalar joint was found. Our data suggest that the subtalar joint orientation may be a risk factor for the development of ankle joint osteoarthritis. Level of Evidence: Level III, retrospective case control study.

Currently used imaging options cannot accurately predict subtalar joint instability

PurposeTo give a systematic overview of current diagnostic imaging options and surgical treatment for chronic subtalar joint instability.MethodsA 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.ResultsConventional 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.ConclusionCurrent 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 evidenceSystematic Review of Level III and Level IV Studies, Level IV.

Training with biofeedback devices improves clinical outcome compared to usual care in patients with unilateral TKA: a systematic review

PurposeBiofeedback following total knee arthroplasty (TKA) seems to be a feasible approach to improve rehabilitation, outcomes, mobility and reduce pain. This systematic review gives the practicing orthopedic surgeon a summary of what is available and how biofeedback affects clinical outcomes.MethodsWe reviewed the current literature regarding methods, devices and effects of biofeedback in patients who underwent total knee arthroplasty. Embase, Pubmed, Web of Science, and Cochrane Central Register of Controlled Trials were searched from inception to May 2018 for the following keywords: Biofeedback OR Feedback AND Total Knee Arthroplasty OR TKA. Data were extracted according to a predefined setting (see Protocol for systematic review on PROSPEO). Devices used for biofeedback were recorded. Demographics, training methods and effects were also collected.ResultsThe search resulted in 380 potentially eligible studies from which 11 met all inclusion criteria including 7 randomized controlled trials (RCTs), 3 cohort studies, and 1 cross-sectional study. A total of 416 patients with unilateral TKA were included, with an average of 37.8 patients per study. In patients with TKA, significant improvements in activity scores or pain were reported by 9 of 11 studies. Only two of the studies reported no significant influence of the feedback on the chosen outcome parameters. Devices for biofeedback varied between studies and included the use of a goniometer, force plate, balance board, treadmill, and/or electromyography (EMG). The most common type of feedback was visual followed by audio, with one study mentioning that the audio mode was preferred by the patients as it was easier to handle. Overall, 5 out of 6 different methods demonstrated a potential value for improving mobility and decreasing pain.ConclusionsThis review suggests that biofeedback in early postoperative rehabilitation after TKA is effective in improving gait symmetry, reducing pain and increasing activity level. It should be noted that the great variety of devices used for feedback limits comparisons between studies.Level of evidenceIIa.

Templating of Syndesmotic Ankle Lesions by Use of 3D Analysis in Weightbearing and Nonweightbearing CT

Background: Diagnosis and operative treatment of syndesmotic ankle injuries remain challenging due to the limitations of 2-dimensional imaging. The aim of this study was therefore to develop a reproducible method to quantify the displacement of a syndesmotic lesion based on 3-dimensional computed imaging techniques. Methods: Eighteen patients with a unilateral syndesmotic lesion were included. Bilateral imaging was performed with weightbearing cone-beam computed tomography (CT) in case of a high ankle sprain (n = 12) and by nonweightbearing CT in case of a fracture-associated syndesmotic lesion (n = 6). The healthy ankle was used as a template after being mirrored and superimposed on the contralateral ankle. The following anatomical landmarks of the distal fibula were computed: the most lateral aspect of the lateral malleolus and the anterior and posterior tubercle. The change in position of these landmarks relative to the stationary, healthy fibula was used to quantify the syndesmotic lesion. A control group of 7 studies was used. Results: The main clinical relevant findings demonstrated a statistically significant difference between the mean mediolateral diastasis of both the sprained (mean [SD], 1.6 [1.0] mm) and the fracture group (mean [SD], 1.7 [0.6] mm) compared to the control group (P < .001). The mean external rotation was statistically different when comparing the sprained (mean [SD], 4.7 [2.7] degrees) and the fracture group (mean [SD], 7.0 [7.1] degrees) to the control group (P < .05). Conclusion: This study evaluated an effective method for quantifying a unilateral syndesmotic lesion of the ankle. Applications in clinical practice could improve diagnostic accuracy and potentially aid in preoperative planning by determining which correction needs to be achieved to have the fibula correctly reduced in the syndesmosis. Level of Evidence: Level III, retrospective comparative study.

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.

Supramalleolar Osteotomy for Tibial Component Malposition in Total Ankle Replacement

Background: Persistent pain despite a total ankle replacement is not uncommon. A main source of pain may be an insufficiently balanced ankle. An alternative to the revision of the existing arthroplasty is the use of a corrective osteotomy of the distal tibia, above the stable implant. This strictly extraarticular procedure preserves the integrity of the replaced joint. The aim of this study was to review a series of patients in whom a corrective supramalleolar osteotomy was performed to realign a varus misaligned tibial component in total ankle replacement. We hypothesized that the supramalleolar osteotomy would correct the malpositioned tibial component, resulting in pain relief and improvement of function. Methods: Twenty-two patients (9 male, 13 female; mean age, 62.6 years; range, 44.7-80) were treated with a supramalleolar osteotomy to correct a painful ankle with a varus malpositioned tibial component. Prospectively recorded radiologic and clinical outcome data as well as complications and reoperations were analyzed. Results: The tibial anterior surface angle significantly changed from 85.2 ± 2.5 degrees preoperatively to 91.4 ± 2.9 degrees postoperatively (P < .0001), the American Orthopaedic Foot & Ankle Society hindfoot score significantly increased from 46 ± 14 to 66 ± 16 points (P < .0001) and the patient’s pain score measured with the visual analog scale significantly decreased from 5.8 ± 1.9 to 3.3 ± 2.4 (P < .001). No statistical difference was found in the tibial lateral surface angle and the range of motion of the ankle when comparing the preoperative to the postoperative measurements. The osteotomy healed in all but 3 patients on first attempt. Fifteen patients (68%) were (very) satisfied, 4 moderately satisfied, and 3 patients were not satisfied with the result. Conclusion: The supramalleolar osteotomy was found to be a reliable treatment option for correcting the varus misaligned tibial component in a painful replaced ankle. However, nonunion (14%) should be mentioned as a possible complication of this surgery. Nonetheless, as a strictly extraarticular procedure, it did not compromise function of the previously replaced ankle, and it was shown to relieve pain without having to have revised a well-fixed ankle arthroplasty. Level of evidence: Level IV, case series.