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

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

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

Stress vs. Non-Stress Radiographs in Subtle Syndesmotic Injuries

Category: Sports Introduction/Purpose: Between 1-18% of all ankle sprains and 23% of all ankle fractures involve injury to the distal tibio-fibular syndesmosis. Syndesmotic injuries can create a substantial diagnostic and therapeutic challenge for orthopaedic surgeons. While acute injuries can be assessed using conventional radiographs, subtle syndesmotic injuries may be misdiagnosed using X-rays. Misdiagnoses may result in chronic ankle instability, pain and post-traumatic osteoarthritis of the tibio-talar joint. The purpose of this study was to investigate whether syndesmotic injury was more easily diagnosed with stress vs. non-stress radiographs.radiographs.sed with stress vs. non-stress radiographs. Methods: Five pairs of cadavers (tibia plateau to toe-tip, mean 61 years, range 52-70 years) were scanned with weight-bearing CT (170 lb, w/ and w/o 10 Nm static external rotation torque). Digitally reconstructed radiographs (DRRs), which are comparable to conventional radiographs, were reconstructed from the 3D CT data. The following conditions were tested: First, intact ankles (Native) were tested. Second, one specimen from each pair underwent AITFL resection, while the contralateral underwent deltoid resection (Condition 1). Third, the remaining intact deltoid ligament or AITFL was resected in each ankle (Condition 2). Finally, the interosseous membrane (IOM) was resected in all ankles (Condition 3). Condition 3 was defined as acute syndesmotic injury. Using antero-posterior (AP) views, the tibio-fibular clear space (TFCS), tibiofibular overlap (TFO) and medial clear space (MCS) were assessed. Statistical analysis was performed using paired (comparison within groups) and unpaired (comparison between groups) t-test where p=0.05 was considered significant. Results: Regarding the TFCS, Native vs. Condition 3 in 10 Nm stress radiographs was significantly different in the deltoid group (p=0.021). Using TFO in stress and non-stressed radiographs, Native vs. Condition 2 and 3 was significantly different for the deltoid group (p=0.043), and Native vs. Condition 3 in the syndesmotic group (p=0.027). Regarding the MCS in non-stress radiographs, Native vs. Condition 3 was significantly different in the deltoid group (p=0.007), while in stress views, Native vs. Condition 2 was significant different in the syndesmotic (p=0.026) and Native vs. Condition 3 in the deltoid group (p=0.030). No differences were found comparing the conditions of the AITFL with the same conditions of the deltoid group. Conclusion: The TFCS cannot be used to assess subtle or acute syndesmotic injuries in stress and non-stress radiographs. The TFO can be used to assess a combined injury to the AITFL and deltoid ligament in stress and non-stress radiographs. The MCS can be used to assess acute syndesmotic injuries in stress and non-stress radiographs. Radiographs (stress or non-stress) cannot be used to distinguish between injuries to the AITFL or deltoid ligament. Therefore, stress and non-stress radiographs are not useful in assessment of subtle syndesmotic injuries. Stress-radiographs are not superior compared to non-stress radiographs in assessment of acute syndesmotic injuries

Can Subtle Syndesmotic Injury Be Assessed Using Weightbearing CT Scans?

Category: Sports Introduction/Purpose: Between 1-18% of all ankle sprains and 23% of all ankle fractures involve injury to the distal tibio-fibular syndesmosis. Syndesmotic injuries can create a substantial diagnostic and therapeutic challenge for orthopaedic surgeons. While acute injuries can be assessed using conventional radiographs, subtle syndesmotic injuries may be misdiagnosed using X-rays. Misdiagnoses may result in chronic ankle instability, pain and post-traumatic osteoarthritis of the tibio-talar joint. Recently, weight-bearing computed tomography (CT) scans gained popularity with foot and ankle surgeons. This method is advantageous in that the distal tibio-fibular syndesmosis can be assessed in greater detail and under weight-bearing conditions. However, there are no studies investigating weight-bearing CT scans for assessment of subtle syndesmotic injury. Methods: Five pairs of cadavers (tibia plateau to toe-tip, mean 61 years, range 52-70 years) were scanned with weight-bearing CT (170 lb) including external rotational torque (10 Nm). The following conditions were tested: First, intact ankles (Native) were tested. Second, one specimen from each pair underwent AITFL resection, while the contralateral underwent deltoid resection (Condition 1). Third, the remaining intact deltoid ligament or AITFL was resected in each ankle (Condition 2). Finally, the interosseous membrane (IOM) was resected in all ankles (Condition 3). Using coronal CT images, the width between the anterior tibia and fibula (A), distance between the anterior tibial incisura and anterior fibula (F), the tibio-fibular overlap (TFO), and the angle between the medial malleolus and the longitudinal axis of the fibula were assessed (a). Statistical analysis was performed using paired (comparison within groups) and unpaired (comparison between groups) t-test where p=0.05 was considered significant. Results: Regarding measurement A, a significant difference (p=0.046) was observed between Condition 2 and 3 vs. Native, independent of which ligament was dissected first. Measurement F was significantly different between Condition 2 and 3 vs. Native (p=0.011) if the AITFL was dissected first, but only reached significance for Condition 3 vs. Native if the deltoid ligament was dissected first (p=0.007). The TFO and a were significant in Conditions 1, 2, and 3 vs. Native if the deltoid ligament was dissected first (p=0.050). When the AITFL was dissected first, significance was reached for the same conditions (p=0.046) with the exception of the TFO for Condition 2 vs. Native. No differences were found when comparing the conditions of the AITFL with the same conditions of the deltoid group. Conclusion: With weight-bearing CT scans and applied external rotation torque, the TFO and angle between the tibia and fibula (a) may be used to assess subtle syndesmotic injury to either the AITFL or the deltoid ligament. When both ligaments (AITFL and deltoid) were injured, the tibio-fibular width (A) and distance between the anterior part of the tibia and fibula (F) could also be used for assessment. Weight-bearing CT scans cannot be used to distinguish between injuries to the AITFL or deltoid ligament. Further studies are needed to assess weight-bearing CT scans in the clinical setting