Anteriorly Translated Talus After Total Ankle Arthroplasty
Anteriorly Translated Talus After Total Ankle Arthroplasty
Mean AOFAS ankle-hindfoot score improved from 46.2 points preoperatively to 93.0 points at the final follow-up in Group A and from 52.5 points preoperatively to 91.0 points at the final follow-up in Group B. There was no significant difference in the AOFAS score during the study period, between the two groups from preoperatively until the final follow-up (Figure 3). Mean ankle range of motion was 28.7 degrees preoperatively and 40.3 degrees at the final follow-up in Group A and 32.5 degrees preoperatively and 39.0 degrees at the final follow-up in Group B. There was also no significant difference in the ROM during the study period, between the 2 groups from preoperative evaluation until the final follow-up (Table 3) (Figure 4).
(Enlarge Image)
Figure 3.
Time course of the postoperative AOFAS scores for the patients of ankle osteoarthritis with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation. There were no significant differences at all study periods.
(Enlarge Image)
Figure 4.
Time course of the postoperative ankle range of motion in the patients with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation. There were no significant differences at all study periods.
Forty-six (92%) of 50 ankles (Group A) with anterior translation of the talus showed relocation of the talus within the mortise at 6 months after primary total ankle arthroplasty, 48 (96%) ankles showed relocation of the talus within the mortise at 12 months, and remained 2 (4%) ankles showed unchanged alignment of the talus until the final follow-up after primary total ankle arthroplasty (Figure 5). The mean tibiotalar ratio in Group A improved from 23.1% preoperatively to 34.5% at the final follow-up. In Group B with non-translation of the talus, the mean tibiotalar ratio improved from 32.4% preoperatively to 35.4% at the final follow-up (Table 4). All ankles of group B had a normal range of tibiotalar ratio postoperatively. During the follow-up period, although the mean tibiotalar ratio of Group A was restored within the normal range (29% to 41%), the mean tibiotalar ratio of Group A had a relatively lower value than that of Group B during the all study period. But, there was no significant difference at 6, 12 months, and at the final follow-up. (p = 0.068, 0.164, 0.368, respectively) (Figure 5).
(Enlarge Image)
Figure 5.
Time course of the postoperative tibiotalar ratio in the patients with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation.
Measured angles, linear values were not significantly different between the 2 groups. In Group A and Group B, the tibial components were positioned in the coronal plane at an average α angle of 89.1 degrees (range, 81.5 to 94.7 degrees) and 89.2 degrees (range, 84.1 to 95.4 degrees), respectively, and in the sagittal plane at an average β angle of 85.2 degrees (range, 81.3 to 94.1 degrees) and 85.4 degrees (range, 79.9 to 92.6 degrees), respectively. The talar component was positioned at an average lateral talar bone-component (γ) angle of 15.7 degrees (range, 7.8 to 24.6 degrees) in Group A and 14.8 degrees (range, 3.6 to 23.2 degrees) in Group B. All parameters (α, β, and γ angle) showed no significant difference (p > 0.05 for each) (Table 4). Talar component subsidence or loosening did not occur in any of the cases.
Additional procedures were carried out before or at the time of total ankle arthroplasty to correct accompanying malalignment, joint contractures, or instabilities, including 17 ankles (34.0%) in group A and 15 ankles (27.8%) in group B (p = 0.354). Preoperatively, an Ilizarov correction for complex ankle deformity was performed in 2 ankles in group B. Intraoperatively, a percutaneous Achilles tendon lengthening procedure was performed 4 ankles (8.0%) in group A and 3 ankles (7.4%) in group B. Deltoid release was performed in 6 ankles (12.0%) in group A and in 4 ankles (7.4%) in group B, and a modified Broström procedure was performed 4 (8.0%) in group A and 3 (7.4%) in group B. One medial malleolar lengthening osteotomy for ligament imbalance, Dwyer osteotomy and syndesmotic fusion were performed in each group.
Sixteen perioperative complications occurred in 11 ankles (22.0%) in group A, and 16 in 14 ankles (25.9%) in group B. There was no significant difference in terms of postoperative complications between the 2 groups (p = 0.663). One (2.0%) deep infection detected in group A at 6 months that required the changing of both tibial and talar components; the patient has had no pain and good functional results at 36 months after revision. Five (10.0%) ankles sustained an intraoperative malleolar fracture in group A and 3 (5.6%) in group B; all were non-displaced and stabilized by screw fixation, and no fracture occurred subsequently. A minor wound complication occurred in 3 (6.0%) ankles in group A and in 5 (9.3%) ankles in group B; all resolved after topical dressing changes. Two (3.7%) cases of deep peroneal neuropraxia occurred in group B, and 3 (6.0%) tendon lacerations occurred in group A (1 flexor hallucis longus and 2 extensor hallucis longus) and 1 (1.8%) in group B (flexor hallucis longus). Symptomatic heterotopic ossification was detected in 2 (4.0%) ankles in group A and 3 (5.6%) ankles in group B. Among them, 2 ankles in group B required surgical resection because of intractable pain and joint stiffness. In each group, there was a single case of medial bony impingement, both of which were managed by osteophyte resection. Tarsal tunnel release was performed on 1 ankle with tarsal tunnel syndrome in each group.
Results
Mean AOFAS ankle-hindfoot score improved from 46.2 points preoperatively to 93.0 points at the final follow-up in Group A and from 52.5 points preoperatively to 91.0 points at the final follow-up in Group B. There was no significant difference in the AOFAS score during the study period, between the two groups from preoperatively until the final follow-up (Figure 3). Mean ankle range of motion was 28.7 degrees preoperatively and 40.3 degrees at the final follow-up in Group A and 32.5 degrees preoperatively and 39.0 degrees at the final follow-up in Group B. There was also no significant difference in the ROM during the study period, between the 2 groups from preoperative evaluation until the final follow-up (Table 3) (Figure 4).
(Enlarge Image)
Figure 3.
Time course of the postoperative AOFAS scores for the patients of ankle osteoarthritis with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation. There were no significant differences at all study periods.
(Enlarge Image)
Figure 4.
Time course of the postoperative ankle range of motion in the patients with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation. There were no significant differences at all study periods.
Forty-six (92%) of 50 ankles (Group A) with anterior translation of the talus showed relocation of the talus within the mortise at 6 months after primary total ankle arthroplasty, 48 (96%) ankles showed relocation of the talus within the mortise at 12 months, and remained 2 (4%) ankles showed unchanged alignment of the talus until the final follow-up after primary total ankle arthroplasty (Figure 5). The mean tibiotalar ratio in Group A improved from 23.1% preoperatively to 34.5% at the final follow-up. In Group B with non-translation of the talus, the mean tibiotalar ratio improved from 32.4% preoperatively to 35.4% at the final follow-up (Table 4). All ankles of group B had a normal range of tibiotalar ratio postoperatively. During the follow-up period, although the mean tibiotalar ratio of Group A was restored within the normal range (29% to 41%), the mean tibiotalar ratio of Group A had a relatively lower value than that of Group B during the all study period. But, there was no significant difference at 6, 12 months, and at the final follow-up. (p = 0.068, 0.164, 0.368, respectively) (Figure 5).
(Enlarge Image)
Figure 5.
Time course of the postoperative tibiotalar ratio in the patients with or without an anteriorly translated talus after primary total ankle arthroplasty. The error bars represent the standard deviation.
Measured angles, linear values were not significantly different between the 2 groups. In Group A and Group B, the tibial components were positioned in the coronal plane at an average α angle of 89.1 degrees (range, 81.5 to 94.7 degrees) and 89.2 degrees (range, 84.1 to 95.4 degrees), respectively, and in the sagittal plane at an average β angle of 85.2 degrees (range, 81.3 to 94.1 degrees) and 85.4 degrees (range, 79.9 to 92.6 degrees), respectively. The talar component was positioned at an average lateral talar bone-component (γ) angle of 15.7 degrees (range, 7.8 to 24.6 degrees) in Group A and 14.8 degrees (range, 3.6 to 23.2 degrees) in Group B. All parameters (α, β, and γ angle) showed no significant difference (p > 0.05 for each) (Table 4). Talar component subsidence or loosening did not occur in any of the cases.
Additional Procedures
Additional procedures were carried out before or at the time of total ankle arthroplasty to correct accompanying malalignment, joint contractures, or instabilities, including 17 ankles (34.0%) in group A and 15 ankles (27.8%) in group B (p = 0.354). Preoperatively, an Ilizarov correction for complex ankle deformity was performed in 2 ankles in group B. Intraoperatively, a percutaneous Achilles tendon lengthening procedure was performed 4 ankles (8.0%) in group A and 3 ankles (7.4%) in group B. Deltoid release was performed in 6 ankles (12.0%) in group A and in 4 ankles (7.4%) in group B, and a modified Broström procedure was performed 4 (8.0%) in group A and 3 (7.4%) in group B. One medial malleolar lengthening osteotomy for ligament imbalance, Dwyer osteotomy and syndesmotic fusion were performed in each group.
Complications
Sixteen perioperative complications occurred in 11 ankles (22.0%) in group A, and 16 in 14 ankles (25.9%) in group B. There was no significant difference in terms of postoperative complications between the 2 groups (p = 0.663). One (2.0%) deep infection detected in group A at 6 months that required the changing of both tibial and talar components; the patient has had no pain and good functional results at 36 months after revision. Five (10.0%) ankles sustained an intraoperative malleolar fracture in group A and 3 (5.6%) in group B; all were non-displaced and stabilized by screw fixation, and no fracture occurred subsequently. A minor wound complication occurred in 3 (6.0%) ankles in group A and in 5 (9.3%) ankles in group B; all resolved after topical dressing changes. Two (3.7%) cases of deep peroneal neuropraxia occurred in group B, and 3 (6.0%) tendon lacerations occurred in group A (1 flexor hallucis longus and 2 extensor hallucis longus) and 1 (1.8%) in group B (flexor hallucis longus). Symptomatic heterotopic ossification was detected in 2 (4.0%) ankles in group A and 3 (5.6%) ankles in group B. Among them, 2 ankles in group B required surgical resection because of intractable pain and joint stiffness. In each group, there was a single case of medial bony impingement, both of which were managed by osteophyte resection. Tarsal tunnel release was performed on 1 ankle with tarsal tunnel syndrome in each group.
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