Subtalar Joint Alignment in Ankle Osteoarthritis

Category: Ankle Arthritis, Hindfoot Introduction/Purpose: The influence of the subtalar joint on the evolution of ankle joint osteoarthritis is still a matter of debate. Although subtalar joint compensation of deformities above the ankle joint was proposed until mid-stage of ankle osteoarthritis, the evidence of this assumption is weak. In this study, we investigated the subtalar joint alignment in different stages of ankle joint osteoarthritis using weightbearing CT scans. The influence of the tibio-talar tilt and presence of subtalar joint osteoarthritis was additionally assessed. We hypothesized, that the subtalar joint compensates for deformities above the ankle joint in early- to mid-stage of ankle osteoarthritis. We also hypothesized, that subtalar joint compensation increases with a pronounced tibio-talar tilt and decreases with the presence of subtalar joint osteoarthritis. Methods: We included patients with ankle joint osteoarthritis treated in our institution from January 2013 to April 2016. A control group of 28 patients was additionally assessed. Varus and valgus ankles were subdivided according to the modified Takakura classification, the tilt of the talus in the ankle mortise and stage of subtalar joint osteoarthritis. The type of ankle osteoarthritis was diagnosed on a plain weightbearing anterior to posterior radiograph of the ankle. The medial distal tibial angle (TAS) and the angle between the tibial shaft and the surface of the talar dome (TTS) were measured. The subtalar joint alignment was assessed using weightbearing CT scans. Two angles were assessed: The subtalar inclination angle (SIA) was measured to investigate the subtalar compensation. For assessment of the morphology of the talus, the inftal-subtal angle (ISA) was determined. Results: This analysis showed significant differences of the subtalar inclination between varus feet and the controls (SIA, P=.001). Regarding the talar morphology, significant differences were found between varus/ valgus feet and the controls (ISA, P=.001 and .036, respectively). No significant differences of the subtalar joint inclination and talar morphology could be identified comparing different stages of ankle joint osteoarthritis inside the varus or valgus group. No relationship between the tilt of the talus in the ankle joint mortise and the subtalar joint inclination or talar morphology was identified. Neither presence nor absence of subtalar joint osteoarthritis influenced the subtalar joint inclination and talar morphology. Conclusion: Varus ankles compensate in the subtalar joint for deformities above the ankle joint. Compensation had no influence on the stage of ankle osteoarthritis, extent of the tibio-talar tilt and stage of subtalar joint osteoarthritis. Consequently, the progression of ankle joint osteoarthritis is more depended on the supramalleolar alignment and integrity of the periarticular structures (i.e. ligaments and tendons) than on the osseous alignment of the subtalar joint

Supramalleolar Osteotomy for Tibial Component Malposition in Total Ankle Replacement

Category: Ankle Introduction/Purpose: A key for success in total ankle replacement is a balanced ankle joint. If the tibial component is misaligned, the ligamentous structures, the malleoli and the tendons may be overused, which, may lead to pain and impairment during gait. A misaligned tibial component can be revised using a corrective bone resection and re-insertion of a new component or using a corrective osteotomy of the distal tibia above the stable implant. The aim of this study was to review a series of patients, in whom a corrective supramalleolar osteotomy was performed to realign a misaligned tibial component in total ankle replacement. Methods: Twenty-two patients (nine male; 13 female; mean age, 62.6 years; range, 44.7 – 80.0) were treated with a supramalleolar osteotomy to correct a painful dysbalanced ankle, following a varus implanted tibial component. Following radiological and clinical outcomes were recorded preoperatively and at the follow-up examination within the first 24 months: the tibial anterior surface angle (TAS), the tibial lateral surface angle (TLS), patient’s pain measured with the Visual Analogue Scale (VAS), the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score, range of motion (ROM) of the ankle and patient’s satisfaction. Furthermore, postoperative complications were reviewed. Results: The TAS changed on average from 85.2 ± 2.5 degrees preoperatively to 91.4 ± 2.9 degrees postoperatively (p < 0.0001), the AOFAS score increased from 46 ± 14 to 66 ± 16 points (p < .0001) and the VAS pain score decreased from 5.8 ± 1.9 to 3.3 ± 2.4 (p < .001). No statistical difference was found in the TLS and the range of motion. The osteotomy healed in 19 patients (86%), re-osteosynthesis was successful in the remaining three patients. In one of these three patients, a chronic infection of the ankle joint led to a below-knee amputation. Fifteen patients (68%) were (very) satisfied, four (18%) moderately satisfied and three (14 %) patients were not satisfied with the obtained postoperative result. Conclusion: The supramalleolar osteotomy was found to be an efficient alternative to correct the misaligned tibial component in total ankle replacement. Pain could be successfully addressed in the majority of the patients. The treatment of a malpositioned, well anchored tibial component with a supramalleolar osteotomy, instead of exchanging the tibial component, allows preservation of the bone stock. However, non-union should be mentioned as a possible complication of this surgery. Nonetheless, this method might be a feasible treatment option, especially for younger patients

Mid- to Long-Term Results of Supramalleolar Osteotomy

Category: Ankle Arthritis Introduction/Purpose: 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 osteoarthritis. However, no mid- to long-term results have been reported. The aim of this study was to gain a better insight on the indications and contraindications for supramalleolar osteotomies. More specific, we assessed the survival rate of a consecutive cohort of 294 patients who underwent supramalleolar osteotomy for ankle osteoarthritis and investigated the effect on functional outcome, pain relief and patients’ satisfaction. Risk factors for failure were additionally determined. We hypothesized, that realignment surgery is a valuable treatment option for young and physically active patients suffering from early to mid-stage ankle osteoarthritis. Methods: Two hundred and ninety-four patients (298 ankles) underwent realignment surgery between December 1999 and June 2013 in our institution. For four patients who were operated on both feet, only the measurements from the foot operated first were used for further analysis. The patients were assessed clinically and radiographically preoperatively, six and 16 weeks postoperatively and thereafter annually. The examination was done by independent examiners who were not involved in the treatment of the patients or analysis of the data. 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. Results: The mean time to follow-up was 5.0 ± 3.7 years. The overall five-year survival rate was 88%. Thirty-eight patients (12.9%) either underwent secondary total ankle replacement or ankle arthrodesis (thirty total ankle replacements, eight ankle arthrodesis). A lost to follow-up was reported in eleven patients (3.7%). Overall, the AOFAS Hindfoot score increased from 53.2 preoperatively (SD, 19.9) to 72.7 (SD, 19.2) postoperatively. Risk factors for failure following realignment surgery were age at the time of surgery and a Takakura score of 3b preoperatively. An interaction by trend was also found between age and smoking, indicating that the increased risk in elderly patients was larger in smokers than in non-smokers at the time of surgery. Conclusion: We found good mid- to long-term results for supramalleolar osteotomies in patients with ankle osteoarthritis. The present data suggests that corrective osteotomies need to be considered in the surgical treatment of young and active patients with early- to mid-stage ankle osteoarthritis (Takakura stage 1 to 3a). This is particularly important, as ankle replacement at young age cannot be considered a lifetime solution. However, care should be taken in elderly patients who smoke at the time of surgery

Invisible Injuries in Ankle Fractures

Category: Ankle, Trauma, Biomechanical Introduction/Purpose: Ankle fractures are often associated with ligamentous injuries of the distal tibiofibular syndesmosis, the deltoid ligament and are predictive of ankle instability, early joint degeneration and long-term ankle dysfunction. Detection of ligamentous injuries and the need for treatment remain subject of ongoing debate. In the classic article of Boden it was made clear that injuries of the syndesmotic ligaments were of no importance in the absence of a deltoid ligament rupture. Even in the presence of a deltoid ligament rupture, the interosseous membrane withstood lateralization of the fibula in fractures up to 4.5 mm above the ankle joint. Generally, syndesmotic ligamentous injuries are treated operatively by temporary fixation performed with positioning screws. But do syndesmotic injuries need to be treated operatively at all? Methods: The purpose of this biomechanical cadaveric study was to investigate the relative movements of the tibia and fibula, under normal physiological conditions and after sequential sectioning of the syndesmotic ligaments. Ten fresh-frozen below-knee human cadaveric specimens were tested under normal physiological loading conditions. Axial loads of 50 Newton (N) and 700 N were provided in an intact state and after sequential sectioning of the following ligaments: anterior-inferior tibiofibular (AITFL), posterior-inferior tibiofibular (PITFL), interosseous (IOL), and whole deltoid (DL). In each condition the specimens were tested in neutral position, 10 degrees of dorsiflexion, 30 degrees of plantar flexion, 10 degrees of inversion, 5 degrees of eversion, and externally rotated up to 10 Nm torque. Finally, after sectioning of the deltoid ligament, we triangulated Boden’s classic findings with modern instruments. We hypothesized that only after sectioning of the deltoid ligament; the lateralization of the talus will push the fibula away from the tibia. Results: During dorsiflexion and external rotation the ankle syndesmosis widened, and the fibula externally rotated after sequential sectioning of the syndesmotic ligaments. After the AITFL was sectioned the fibula starts rotating externally. However, the external rotation of the fibula significantly reduced when the external rotation torque was combined with axial loading up to 700 N as compared to the external rotation torque alone. The most relative moments between the tibia and fibula were observed after the deltoid ligament was sectioned. Conclusion: Significant increases in movements of the fibula relative to the tibia occur when an external rotation torque is provided. However, axial pressure seemed to limit external rotation because of the bony congruence of the tibiotalar surface. The AITFL is necessary to prevent the fibula to rotate externally when the foot is rotating externally. The deltoid ligament is the main stabilizer of the ankle mortise

Location of Activation of Tarsal Joints on SPECT CT Scan Predicts Preoperative Functional and Pain Scores on Supramalleolar Osteotomy Patients

Category: Ankle, Ankle Arthritis Introduction/Purpose: Combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT) is a hybrid imaging modality that shows a combination of metabolic and structural information about the ankle. Recently, its use has expanded for pre-operative evaluation of supramalleolar osteotomies (SMO) for asymmetric ankle arthritis. It is unclear if the location of bone scan activation in other locations in the hindfoot is related to pre and post-operative functional and scores. We hypothesize that uptake in specific locations within the hindfoot can be associated with worse pre- and post- operative functional and pain scores. Methods: 85 pre-operative SMO patients with varus (37), valgus (41), or neutral (7) alignment of the hindfoot were assessed using SPECT/CT. The level of activation on SPECT/CT scans was measured. Activation was assessed on both the tibia and talus including the talonavicular, subtalar, calcaneocuboid joints and subfibular region. Pre- and post-operative functional and pain scores (AOFAS Hindfoot, FAOS, and VAS) were recorded for each patient at an average of 3.7 years post-operatively. We compared SPECT/CT imaging with pre-operative patient scores assuming equal group variance and used a Chi-square analysis to determine if failure can be related to having activation in other joints besides the hindfoot. Results: Those with talonavicular (6) activation had worse malalignment as measured by the AOFAS Hindfoot-A (alignment) subscore; they had worse a functional status as measured by the AOFAS-F (function) subscore. Patients with subtalar joint activation (10) had significantly worse (p<.05) pre-operative VAS pain scores. They also had worse AOFAS-F, AOFAS Hindfoot, and FAOS-S (symptom) scores. Those with calcaneocuboid activation (1) did not have any correlation to pre-operative pain or functional scores. Patients with subfibular impingement (7) had worse alignment based on the AOFAS-A scores. Patients with hindfoot joint activation did not have a higher rate of failure relative to other locations in the ankle. Activation in these areas were not associated with any post-operative functional or pain scores. Conclusion: Pre-operative SPECT/CT evaluation of the hindfoot before a SMO can be used to clinically correlate patient-specific factors such as pain and function in the pre-operative period. Results from this study provide prognostic information the locations of lesions that may cause patients more functional disability and pain pre-operatively and in the future