Avoidance of injury to the posterior neurovascular bundle during total ankle arthroplasty - A simple technical tip.

Iatrogenic nerve injury to the tibial nerve is a serious but avoidable complication of total ankle replacements and may be under-reported as it may go unrecognised or thought to be due to tarsal tunnel syndrome. The tibial nerve is particularly vulnerable during the saw cuts at the posteromedial corner without appropriate protection. Prior to drilling the tibial and talar pins of the adjustment block for the Infinity ankle replacement we perform a 2 cm incision behind the medial malleolus. The tibialis posterior tendon sheath is identified and incised. A periosteal elevator is used to develop a plane between the back of the tibia and the tibialis posterior tendon and then exchanged for a mini Hohmann retractor protecting the neurovascular bundle. This allows us to drill the pins and saw cuts safely. The Hohmann retractor can be felt at the tip of the saw blade providing reassurance that the blade is not too deep. Our technique has not previously been reported in the literature. It acts as a simple reproducible way of avoiding injury to structures at the back of the ankle joint.

Is Lower-limb Alignment Associated with Hindfoot Deformity in the Coronal Plane? A Weightbearing CT Analysis.

BACKGROUND: The goals of lower limb reconstruction are to restore alignment, to improve function, and to reduce pain. However, it remains unclear whether alignment of the lower limb and hindfoot are associated because an accurate assessment of hindfoot deformities has been limited by superposition on plain radiography. Consequently, surgeons often overlook hindfoot deformity when planning orthopaedic procedures of the lower limb. Therefore, we used weight-bearing CT to quantify hindfoot deformity related to lower limb alignment in the coronal plane. QUESTIONS/PURPOSES: (1) Is lower-limb alignment different in varus than in valgus hindfoot deformities for patients with and without tibiotalar joint osteoarthritis? (2) Does a hindfoot deformity correlate with lower-limb alignment in patients with and without tibiotalar joint osteoarthritis? (3) Is joint line orientation different in varus than in valgus hindfoot deformities for patients with tibiotalar joint osteoarthritis? (4) Does a hindfoot deformity correlate with joint line orientation in patients with tibiotalar joint osteoarthritis? METHODS: Between January 2015 and December 2017, one foot and ankle surgeon obtained weightbearing CT scans as second-line imaging for 184 patients with ankle and hindfoot disorders. In 69% (127 of 184 patients) of this cohort, a combined weightbearing CT and full-leg radiograph was performed when symptomatic hindfoot deformities were present. Of those, 85% (109 of 127 patients) with a median (range) age of 53 years (23 to 75) were confirmed eligible based on the inclusion and exclusion criteria of this retrospective comparative study. The Takakura classification was used to divide the cohort into patients with (n = 74) and without (n = 35) osteoarthritis of the tibiotalar joint. Lower-limb measurements, obtained from the full-leg radiographs, consisted of the mechanical tibiofemoral angle, mechanical tibia angle, and proximal tibial joint line angle. Weightbearing CT images were used to determine the hindfoot's alignment (mechanical hindfoot angle), the tibiotalar joint alignment (distal tibial joint line angle and talar tilt angle) and the subtalar joint alignment (subtalar vertical angle). These values were statistically assessed with an ANOVA and a pairwise comparison was subsequently performed with Tukey's adjustment. A linear regression analysis was performed using the Pearson correlation coefficient (r). A reliability analysis was performed using the intraclass correlation coefficient. RESULTS: Lower limb alignment differed among patients with hindfoot deformity and among patients with or without tibiotalar joint osteoarthritis. In patients with tibiotalar joint osteoarthritis, we found knee valgus in presence of hindfoot varus deformity and knee varus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle 0.3 ± 2.6° versus -1.8 ± 2.1°; p < 0.001; mechanical tibia angle -1.4 ± 2.2° versus -4.3 ± 1.9°; p < 0.001). Patients without tibiotalar joint osteoarthritis demonstrated knee varus in the presence of hindfoot varus deformity compared with knee valgus in presence of hindfoot valgus deformity (mechanical tibiofemoral angle -2.2 ± 2.2° versus 0.9 ± 2.4°; p < 0.001; mechanical tibia angle -1.8 ± 2.1° versus -4.3 ± 1.9°; p < 0.001). Patients with more valgus deformity in the hindfoot tended to have more tibiofemoral varus (r = -0.38) and tibial varus (r = -0.53), when tibiotalar joint osteoarthritis was present (p < 0.001). Conversely, patients with more valgus deformity in the hindfoot tended to have more tibiofemoral valgus (r = 0.4) and tibial valgus (r = 0.46), when tibiotalar joint osteoarthritis was absent (p < 0.001). The proximal joint line of the tibia had greater varus orientation in patients with a hindfoot valgus deformity compared with greater valgus orientation in patients with a hindfoot varus deformity (proximal tibial joint line angle 88.5 ± 2.0° versus 90.6 ± 2.2°; p < 0.05). Patients with more valgus deformity in the hindfoot tended to have more varus angulation of the proximal tibial joint line angle (r = 0.31; p < 0.05). CONCLUSIONS: In patients with osteoarthritis of the tibiotalar joint, varus angulation of the knee was associated with hindfoot valgus deformity and valgus angulation of the knee was associated with hindfoot varus deformity. Patients without tibiotalar joint osteoarthritis exhibited the same deviation at the level of the knee and hindfoot. These distinct radiographic findings were most pronounced in the alignment of the tibia relative to the hindfoot deformity. This suggests a detailed examination of hindfoot alignment before knee deformity correction at the level of the proximal tibia, to avoid postoperative increase of pre-existing hindfoot deformity. Other differences detected between the radiographic parameters were less pronounced and varied within the subgroups. Future research could identify prospectively which of these parameters contain clinical relevance by progressing osteoarthritis or deformity and how they can be altered by corrective treatment. LEVEL OF EVIDENCE: Level III, prognostic study.

Outcome after arthroscopically assisted percutaneous reconstruction of lateral ankle ligaments using a gracilis tendon autograft.

In cases of chronic instability of the lateral ligament complex following an ankle sprain, operative stabilization should be considered when conservative treatment fails. The purpose of this study is to determine the outcome of a percutaneous stabilization of the lateral ligament complex with a gracilis tendon auto-graft, after an adjuvant arthroscopy of the ankle joint. We retrospectively reviewed the medical files of patients who underwent this surgery performed by the senior author. Between 2012 and 2015, 18 ankles were stabilized. Clinical results were assessed at final follow-up at a mean post-operative period of 25 months (range, 10-42 months). The mean post-operative AOFAS ankle-hindfoot score was 90 points (range, 48-100 points). The mean Karlsson Ankle Functional Score was 85 points (range, 37-100 points). The mean VAS score was 1.2 (range, 0-7). Concomitant procedures were performed on 14 out of 18 ankles. In conclusion, we state that this arthroscopically assisted percutaneous technique is a viable treatment option for chronic lateral ankle instability. It offers an alternative for the modified Broström procedure when tissue quality is poor and carries all the advantages of a minimally invasive procedure.

EFAS Score - Multilingual development and validation of a patient-reported outcome measure (PROM) by the score committee of the European Foot and Ankle Society (EFAS).

BACKGROUND: A scientifically sound validated foot and ankle specific score validated ab initio for different languages is missing. The aim of a project of the European Foot and Ankle Society (EFAS) was to develop, validate, and publish a new score(the EFAS-Score) for different European languages. METHODS: The EFAS Score was developed and validated in three stages: (1) item (question) identification, (2) item reduction and scale exploration, (3) confirmatory analyses and responsiveness. The following score specifications were chosen: scale/subscale (Likert 0-4), questionnaire based, outcome measure, patient related outcome measurement. For stage 3, data were collected pre-operatively and at a minimum follow-up of 3 months and mean follow-up of 6 months. Item reduction, scale exploration, confirmatory analyses and responsiveness were executed using analyses from classical test theory and item response theory. RESULTS: Stage 1 resulted in 31 general and 7 sports related questions. In stage 2, a 6-item general EFAS Score was constructed using English, German, French and Swedish language data. In stage 3, internal consistency of the scale was confirmed in seven languages: the original four languages, plus Dutch, Italian and Polish (Cronbach's Alpha >0.86 in all language versions). Responsiveness was good, with moderate to large effect sizes in all languages, and significant positive association between the EFAS Score and patient-reported improvement. No sound EFAS Sports Score could be constructed. CONCLUSIONS: The multi-language EFAS Score was successfully validated in the orthopaedic ankle and foot surgery patient population, including a wide variety of foot and ankle pathologies. All score versions are freely available at www.efas.co.

Statistical shape model-based tibiofibular assessment of syndesmotic ankle lesions using weight-bearing CT.

Forced external rotation is hypothesized as the key mechanism of syndesmotic ankle injuries, inducing a three-dimensional deviation from the normal distal tibiofibular joint (DTFJ) alignment. However, current diagnostic imaging modalities are impeded by a two-dimensional assessment, without considering ligamentous stabilizers. Therefore, our aim is threefold: (1) to construct an articulated statistical shape model of the normal DTFJ with the inclusion of ligamentous morphometry, (2) to investigate the effect of weight-bearing on the DTFJ alignment, and (3) to detect differences in predicted syndesmotic ligament length of patients with syndesmotic lesions with respect to normative data. Training data comprised non-weight-bearing CT scans from asymptomatic controls (N = 76), weight-bearing CT scans from patients with syndesmotic ankle injury (N = 13), and their weight-bearing healthy contralateral side (N = 13). Path and length of the syndesmotic ligaments were predicted using a discrete element model, wrapped around bony contours. Statistical shape model evaluation was based on accuracy, generalization, and compactness. The predicted ligament length in patients with syndesmotic lesions was compared with healthy controls. With respect to the first aim, our presented skeletal shape model described the training data with an accuracy of 0.23 ± 0.028 mm. Mean prediction accuracy of ligament insertions was 0.53 ± 0.12 mm. In accordance with the second aim, our results showed an increased tibiofibular diastasis in healthy ankles after weight-bearing. Concerning our third aim, a statistically significant difference in anterior syndesmotic ligament length was found between ankles with syndesmotic lesions and healthy controls (p = 0.017). There was a significant correlation between the presence of syndesmotic injury and the positional alignment between the distal tibia and fibula (r = 0.873, p < 0,001). Clinical Significance: Statistical shape modeling combined with patient-specific ligament wrapping techniques can facilitate the diagnostic workup of syndesmosic ankle lesions under weight-bearing conditions. In doing so, an increased anterior tibiofibular distance was detected, corresponding to an "anterior open-book injury" of the ankle syndesmosis as a result of anterior inferior tibiofibular ligament elongation/rupture.

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.