How Does a Novel In Situ Fixed-bearing Implant Design Perform in Revision Ankle Arthroplasty in the Short Term? A Survival, Clinical, and Radiologic Analysis.

BACKGROUND: Given the growing number of primary total ankle replacements (TAR), an increase in the number of patients undergoing subsequent revisions might be expected. Achieving a stable and balanced ankle while preserving the remaining bone stock as much as possible is crucial for success in revision TAR. Most reported techniques rely on bulky implants with extended fixation features. Since 2018, we have used a novel, three-component ankle prosthesis for revision that is converted in situ to a fixed-bearing, two-component ankle prosthesis once the components have found their position according to an individual's anatomy. The results of this novel concept (fixation, revision, pain, or function) have not, to our knowledge, been reported. QUESTIONS/PURPOSES: What are the short-term results with this new revision TAR design, in terms of (1) repeat revision surgery, (2) patient-reported outcomes on the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, (3) pain according to the VAS, and (4) radiographic signs of fixation? METHODS: Between February 2018 and February 2020, we performed 230 TAR surgeries (in 206 patients) for any indication in our clinic. The novel semiconstrained, uncemented Hintermann Series H2 © implant was used in 96% (220 of 230) of procedures (201 patients). Fifty-four percent (119 of 220) of these were converted from an existing TAR to H2, which was the focus of the present study. However, only 45% (54 of 119) of these conversions to H2 were eligible for analysis. These patients had a mean age of 63 ± 12 years, and 43% (23 of 54) were women. The median (range) follow-up time was 3.2 years (2.0 to 4.3). The H2 design allows in situ conversion to a fixed-bearing system, with minimal bone resection. It achieves translational and rotational stability while preserving function and supporting the periarticular soft tissues. We defined repeat revision as exchange of one or both metal components, ankle fusion, or amputation and assessed it using a cumulative incidence survivorship estimator. Factors potentially associated with revision were assessed using Cox regression analyses. Clinical and radiologic outcomes were assessed preoperatively and at the most recent follow-up interval. Clinical outcomes included pain on the VAS (average pain during normal daily activity during the past seven days) and AOFAS score. Radiologic outcomes were the tibial articular surface angle, tibiotalar surface angle, talar tilt angle in the coronal plane, and AP offset ratio in the sagittal plane, as well as radiolucent lines and radiographic signs of loosening, defined as change in position greater than 2° of the flat base of the tibia component in relation to the long axis of the tibia, subsidence of the talar component into the talus greater than 5 mm, or change in position greater than 5° relative to a line drawn from the top of the talonavicular joint to the tuberosity of the calcaneus, as seen on plain weightbearing radiographs. RESULTS: The cumulative incidence of repeat revision after 1 and 2 years was 5.6% (95% CI 0% to 11%) and 7.4% (95% CI 0% to 14%), respectively. With the numbers available, no clinical factors we analyzed were associated with the risk of repeat revision. The median values of all assessed clinical outcomes improved; however, not all patients improved by clinically important margins. The median (range) AOFAS ankle-hindfoot score increased (from 50 [16 to 94] to 78 [19 to 100], difference of medians 28; p < 0.01), and the median pain on the VAS decreased (from 5 [0 to 9] to 2 [0 to 9], difference of medians 3; p < 0.01) from before surgery to follow-up at a minimum of 2 years. Radiographically, lucency was seen in 12% (6 of 49 patients) and loosening was seen in 8% (4 of 49). One of these patients showed symptomatic loosening and was among the four patients overall who underwent revision. We could not assess risk factors for repeat revision because of the low number of events (four). CONCLUSION: The investigated new in situ fixed-bearing ankle design achieved overall better short-term results than those reported in previous research. Destabilization of the ankle joint complex, soft tissue insufficiency, and possible changes of the joint configuration need an optimal solution in revision arthroplasty. The studied implant might be the answer to this complex issue and help surgeons in the perioperative decision-making process. However, a relatively high percentage of patients did not achieve a clinically important difference. Observational studies are needed to understand long-term implant behavior and possibly to identify ankles benefiting the most from revision. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Open anatomical glenoid reconstruction with an iliac crest bone autograft effectively resolves off-track Hill-Sachs lesions to on-track lesions.

INTRODUCTION: The purpose of this study was to determine if "off-track" Hill-Sachs lesions in patients with dynamic anteroinferior instability were transformed into "on-track" lesions using iliac bone autografts with screw fixation. The secondary purpose was to observe if postoperative bony remodeling would occur over time, resulting in recurrent "off-track" Hill-Sachs lesions with corresponding instability. MATERIALS AND METHODS: We retrospectively reviewed clinical and CT records of 8 patients with an "off-track" Hill-Sachs lesion who underwent open anatomical glenoid reconstruction with an iliac crest bone autograft. Hill-Sachs lesions, glenoid track widths, and glenoid surface areas were measured on a preoperative and two postoperative (6 weeks, ≥ 2 years) 3D-CT models to determine graft resorption over time. All patients were available for postoperative clinical and CT final follow-up 3 years (2-4 years) postoperatively. RESULTS: In all patients, the Hill-Sachs lesions were "on-track" 6 weeks postoperatively and remained "on-track" at final-follow-up. Compared to preoperative values, the glenoid track width and glenoid surface area both were higher 6 weeks postoperatively (p < 0.001 and p = 0.023, respectively) and at final follow-up (p < 0.001 and p = 0.023, respectively). Whereas the glenoid track width between 6 weeks and final follow-up showed no decrease (p = 0.234), glenoid surface area tended to decrease (p = 0.055). The median SSV was 93 points (85-95 points), the Rowe score 90 points (80-100 points) and the WOSI 1980 points (1783-2067 points) at final follow-up. No recurrent dislocations or subluxations were observed. CONCLUSIONS: An open anatomical glenoid reconstruction with an iliac crest bone autograft technique using screw fixation effectively transformed "off-track" Hill-Sachs lesions to "on-track" lesions, resulting in good short-term clinical outcomes. Whereas glenoid surface area tended to be reduced by bony remodeling processes over time, the glenoid track width did not decrease at final follow-up and consequently no recurrence of "off-track" lesions occurred. LEVEL OF EVIDENCE: Case series; Level of evidence, IV.

Effect of total ankle replacement on the 3-dimensional subtalar joint alignment in varus ankle osteoarthritis.

BACKGROUND: Varus ankle osteoarthritis (OA) is typically associated with peritalar instability, which may result in altered subtalar joint position. This study aimed to determine the extent to which total ankle replacement (TAR) in varus ankle OA can restore the subtalar alignment. METHODS: Fourteen patients (15 ankles, mean age 61 ± 6 years) who underwent TAR for varus ankle OA were analyzed using semi-automated measurements based on weight-bearing computed tomography. Twenty healthy individuals served as a control group. RESULTS: All angles improved between preoperative and a minimum of 1 year (mean 2.1 years) postoperative and were statistically significant in 6 out of 8 angles (P < 0.05). CONCLUSIONS: Our findings indicate that talus repositioning after TAR restores the subtalar joint alignment which may improve hindfoot biomechanics. Future studies are required to implement these findings for TAR in presence of hindfoot deformity. LEVEL OF EVIDENCE: IV.

What Are the Indications for Implant Revision in Three-component Total Ankle Arthroplasty?

BACKGROUND: Given the increasing usage of total ankle arthroplasty (TAA), a better understanding of the reasons leading to implant revision and the factors that might influence those indications is necessary to identify at-risk patients. QUESTION/PURPOSES: Using a single-design three-component ankle prosthesis, we asked: (1) What is the cumulative incidence of implant revision at 5 and 10 years? (2) What are the indications for implant revision in our population? (3) What factors are associated with an increased likelihood of implant revision during the time frame in question? METHODS: Between 2003 and 2017, primary TAA using a single-design three-component ankle implant was performed by or under the supervision of the implant designer in 1006 patients (1074 ankles) aged between 17 and 88 years to treat end-stage ankle osteoarthritis. No other TAA systems were used during the study period at the investigators' institution. In 68 patients with bilateral surgery, only the first TAA was considered. Of the patients treated with the study implant, 2% (16 of 1006) were lost to follow-up 5 to 14 years after TAA and were not known to have died or undergone revision, and 5% (55 of 1006) were deceased due to reasons unrelated to the procedure, leaving 935 patients for evaluation in this retrospective study. The mean (range) follow-up for the included patients was 8.8 ± 4.2 (0.2 to 16.8) years. Implant revision was performed 0.5 to 13.2 years after TAA in 12% (121 of 1006) of our patients. Survivorship free from revision was calculated using cumulative incidence (competing risks) survivorship, with death as a competing risk. The reason for each revision was classified into one of six categories according to a modified version of a previously published protocol: aseptic loosening, cyst formation, instability, deep infection, technical error, and pain without another cause. Two foot and ankle surgeons reviewed the records of all patients who underwent implant revision and assigned each patient's reason for revision to one of the six categories. The decision for assigning each patient to one of the six categories was made based on a consensus agreement. A subgroup classification of preoperative ankle alignment (neutral, mild, and major deformity) and variables of age, sex, BMI, etiology of ankle osteoarthritis, and number of preoperative and intraoperative hindfoot or midfoot procedures were used in a multinomial logistic regression and Cox regression analysis to estimate their association with reason for revision and implant survival until revision. RESULTS: The cumulative incidence of implant revision at the mean (range) follow-up time of 8.8 ± 4.2 years (0.2 to 16.8) was 9.8% (95% confidence interval 7.7% to 11.8%). Five and 10 years after TAA, cumulative incidence was 4.8% (95% CI 3.4 to 6.1) and 12.1% (95% CI 9.7% to 14.5%), respectively. The most common reason for revision was instability (34% [41 of 121]), followed by aseptic loosening of one or more metallic components (28% [34 of 121]), pain without another cause (12% [14 of 121]), cyst formation (10% [12 of 121]), deep infection (9% [11 of 121]), and technical error (7% [9 of 121]). Ankles with a major hindfoot deformity before TAA were more likely to undergo revision than ankles with a minor deformity (hazard ratio 1.9 [95% CI 1.2 to 3.0]; p = 0.007) or neutral alignment (HR 2.5 [95% CI 1.5 to 4.4]; p = 0.001). A preoperative hindfoot valgus deformity increased revision probability compared with a varus deformity (HR 2.1 [95% CI 1.4 to 3.4]; p = 0.001). CONCLUSION: Instability was a more common reason for implant revision after TAA with this three-component design than previously reported. All causes inducing either a varus or valgus hindfoot deformity must be meticulously addressed during TAA to prevent revision of this implant. Future studies from surgeons/institutions not involved in this implant design are needed to confirm these findings and to further investigate why a substantial number of patients had pain of unknown cause prompting revision. LEVEL OF EVIDENCE: Level III, therapeutic study.

Mid- to long-term outcome in patients treated with a mini-open sinus-tarsi approach for calcaneal fractures.

BACKGROUND: While the extended lateral approach was the gold standard for treatment of calcaneal fractures for decades, the mini-open approach through the sinus tarsi gained popularity in recent years. Although widely used, there are only a few reports available in the literature reporting on mid- to long-term results. Therefore, the purpose of the study was to report on mid- to long-term radiographic and clinical outcomes of calcaneal fractures treated surgically using a mini-open sinus tarsi approach. MATERIALS AND METHODS: In this retrospective review, radiographic and clinical outcome measures of 30 consecutive patients (34 fractures) were analyzed. Conventional radiographs were used to measure the Boehler's angle before and after surgical fixation. Computed tomography (CT) scans were analyzed to distinguish between joint depression and tongue-type calcaneal fractures. Each calcaneal fracture was additionally categorized according to the Sanders classification. The clinical outcome was measured using a 5-point Likert scale ranging from 0 (very unsatisfied) to 4 (very satisfied), the Visual Analog Scale (VAS) for pain, and the Maryland Foot Score. RESULTS: The Boehler's angle improved from 12.6 degrees preoperatively to 26.3 degrees postoperatively (P < 0.001). Loss of sagittal reduction (i.e., a decline of the Boehler's angle of > 5 degrees) from postoperative to the last follow-up was evident in nine (26%) fractures. Out of 29 patients with an available satisfaction score, 20 (69%) were very satisfied, 8 (28%) were satisfied, and one (3%) was moderately satisfied. Satisfaction at the last follow-up declined with higher age at surgery. An overall low complication rate was evident, with painful hardware needing removal being the most common complication. CONCLUSIONS: Approaching calcaneus fractures through the sinus tarsi provides satisfactory mid- to long-term radiographic and clinical outcomes, independent of the severity of the fractures according to the Sanders classification. LEVEL OF EVIDENCE: Level IV, Retrospective Case Series.

Supramalleolar osteotomy in post-traumatic valgus ankle osteoarthritis.

PURPOSE: To assess how the level of the deformity, the stage of the osteoarthritic process, and the role of additional surgeries impact radiographic and clinical outcomes following an extra-articular medial closing supramalleolar osteotomy for treatment of post-traumatic valgus ankle osteoarthritis. METHODS: About 56 consecutive patients who underwent an extra-articular medial closing wedge osteotomy for post-traumatic valgus ankle osteoarthritis were retrospectively analyzed. Subgroups were formed according to the pre-operative level of deformity and preoperative stage of ankle osteoarthritis. Additional surgical steps required to achieve a properly balanced hindfoot were also noted. Radiographic and clinical outcomes of each subgroup were compared with each other, and the role of additional surgical steps required to achieve a balanced hindfoot was investigated. RESULTS: Radiographic and clinical outcomes improved significantly between pre-operative assessment and the last follow-up. Patients with a pre-operative supramalleolar deformity showed superior radiographic outcomes compared to patients with an intra-articular deformity. Clinical outcomes did not differ significantly between these two subgroups. The pre-operative stage of ankle osteoarthritis significantly impacted radiographic outcomes but did not influence clinical outcome measures. An additional fibula or calcaneus osteotomy was necessary for 55% and 23% of all patients, respectively. CONCLUSION: Extra-articular medial closing supramalleolar osteotomies show satisfactory mid- to long-term radiographic and clinical outcomes in patients with post-traumatic valgus ankle osteoarthritis.

Hindfoot balancing in total ankle replacement: the role of supramalleolar osteotomies.

PURPOSE: To compare the obtained deformity correction and clinical/functional outcomes between patients who underwent total ankle replacement (TAR) with or without a concurrent supramalleolar osteotomy (SMO) to address a varus and/or recurvatum deformity of the distal tibia. METHODS: Data of 23 patients treated with an additional SMO to correct a varus and/or recurvatum deformity of the distal tibia at the time of TAR were prospectively collected. Twenty-three matched patients who underwent TAR only served as controls. RESULTS: The American Orthopaedic Foot and Ankle Society (AOFAS)-hindfoot scale and pain assessed on a Visual Analogue Scale (VAS) did not significantly differ between the two groups at the final follow-up (AOFAS-hindfoot scale SMO/TAR group = 82 ± 10; TAR group = 82 ± 12; VAS pain SMO/TAR group = 1 (range, 0-4); TAR group = 1 (range, 0-5)). Ankle range of motion (ROM) did not improve in the SMO/TAR group (pre-operative = 27 ± 13 degrees, last follow-up = 30 ± 9 degrees; P = .294), but did improve in the TAR group (pre-operative = 31 ± 14 degrees, last follow-up = 39 ± 14 degrees; P = .049). Two patients who underwent SMO/TAR showed non-union of the tibial osteotomy, and two patients who underwent TAR only suffered from an intra-operative medial malleolar fracture. CONCLUSION: An additional SMO during TAR in patients with a varus and/or recurvatum deformity of the distal tibia is not beneficial in most cases and should only be considered in pronounced multiplanar deformities.

Survival and risk assessment in revision arthroplasty of the ankle.

Aims: Implant failure has become more common as the number of primary total ankle arthroplasties (TAAs) performed has increased. Although revision arthroplasty has gained attention for functional preservation, the long-term results remain unclear. This study aimed to assess the long-term outcomes of revision TAA using a mobile-bearing prosthesis in a considerably large cohort; the risk factors for failure were also determined. Methods: This single-centre retrospective cohort study included 116 patients (117 ankles) who underwent revision TAA for failed primary TAA between July 2000 and March 2010. Survival analysis and risk factor assessment were performed, and clinical performance and patient satisfaction were evaluated preoperatively and at last follow-up. Results: The mean duration from initial revision TAA to last follow-up was 15.0 years (SD 3.0; 11.2 to 20.5). The cumulative survival rates of the revised ankles were 81% (95% confidence interval (CI) 74% to 88%), 74% (65% to 82%), and 70% (61% to 79%) at five, ten, and 15 years, respectively. Comorbidities prior to primary TAA, aseptic loosening, instability, or grafting of cysts were found to be the most common risk factors for secondary revision. The median value for preoperative pain, as assessed using the visual analogue scale, declined from 6 (interquartile range (IQR) 5 to 8) to 2 (IQR 0 to 5) (p < 0.001) and the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot score improved from 43 (SD 17) preoperatively to 70 (SD 20) (p < 0.001) at last follow-up. Conclusion: Revision TAA offers acceptable survival rates after 15 years; it therefore offers a valuable option for treatment of implant failure in carefully selected cases. Although patient-reported outcomes improve substantially, the degree of improvement reported following primary TAA is not achieved.

Supramalleolar Osteotomy for Ankle Varus Deformity Alters Subtalar Joint Alignment.

BACKGROUND: Although correction of ankle and hindfoot deformity after supramalleolar osteotomy has been investigated extensively, the specific effect on the subtalar joint alignment remains elusive. This can be attributed to the limitations of 2-dimensional measurements, which impede an exact quantification of the 3-dimensional subtalar joint alignment. Therefore, we determined both the ankle, hindfoot, and subtalar joint alignment before and after supramalleolar osteotomy using autogenerated 3-dimensional measurements based on weightbearing CT imaging. METHODS: Twenty-nine patients with a mean age of 50.4±10.6 years were retrospectively analyzed in a pre-post study design using weightbearing CT. Inclusion criteria were correction of ankle varus deformity by an opening wedge (n = 22) or dome osteotomy (n = 7). Exclusion criteria consisted of an additional inframalleolar arthrodesis or osteotomy. Corresponding 3-dimensional bone models were reconstructed to compute following autogenerated measurements of the ankle- and hindfoot alignment: tibial anterior surface (TAS), tibiotalar surface (TTS), talar tilt (TT) angle, hindfoot angle (HA). In addition, the talocalcaneal angle (TCA) in the axial (TCAax), sagittal (TCAsag), and coronal (TCAcor) plane were measured to assess the subtalar joint alignment. RESULTS: The preoperative radiographic parameters of the ankle joint alignment (TAS=88±4 degrees, TTS=82±7 degrees, TT=5.8±4.9 degrees) improved significantly relative to their postoperative equivalents (TAS = 93±5 degrees, TTS = 88±7 degrees, TT=4.2±4.5 degrees; P < .05). The following radiographic parameters of the hindfoot and subtalar joint alignment improved significantly from preoperatively (8.7±8.9 degrees, TCAax = 41±10 degrees, TCAsag = 48±10 degrees) to postoperatively (HA=4.5±8.6 degrees, TCAax = 38±9 degrees, TCAsag = 44±11 degrees; P < .05). No significant differences could be detected in the coronal plane alignment of the subtalar joint (TCAcor) pre- compared to postoperatively (P > .05). CONCLUSION: This study quantified the 3-dimensional ankle, hindfoot, and subtalar joint alignment after a solitary supramalleolar osteotomy. We found alterations in the subtalar joint alignment, which occurred by 2 to 3 degrees in each anatomic plane. However, before recommendations can be given related to inframalleolar procedures in conjunction to supramalleolar osteotomies, further studies on the variation of subtalar joint alignment change are needed.

Long-Term Survival of HINTEGRA Total Ankle Replacement in 683 Patients: A Concise 20-Year Follow-up of a Previous Report.

LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Assessment of Progressive Collapsing Foot Deformity Using Semiautomated 3D Measurements Derived From Weightbearing CT Scans.

BACKGROUND: In progressive collapsing foot deformity (PCFD), hind- and midfoot deformities can be hard to characterize based on weightbearing plain radiography. Semiautomated 3-dimensional (3D) measurements derived from weightbearing computed tomography (WBCT) scans may provide a more accurate deformity assessment. In the present study, automated 3D measurements based on WBCT were used to compare hindfoot alignment of healthy individuals to patients with PCFD. METHODS: The WBCT scans of 20 patients treated at our institution with either a flexible (N = 10) or rigid (N = 10) PCFD were compared with the WBCT scans of a control group of 30 healthy individuals. Using semiautomated image analysis software, from each set of 3D voxel images, we measured the talar tilt (TT), hindfoot moment arm (HMA), talocalcaneal angle (TCA; axial/lateral), talonavicular coverage (TNC), and talocalcaneal overlap (TCO). The presence of medial facet subluxation as well as sinus tarsi/subfibular impingement was additionally assessed. RESULTS: With the exception of the TCA (axial/lateral), the analyzed measurements differed between healthy individuals and patients with PCFD. The TCA axial correlated with the TNC in patients with PCFD. An increased TCO combined with sinus tarsi impingement raised the probability of predicting a deformity as rigid. CONCLUSION: Using 3D measurements, in this relatively small cohort of patients, we identified relevant variables associated with a clinical presentation of flexible or rigid PCFD. An increased TCO combined with sinus tarsi impingement raised the probability of predicting a deformity as rigid. Such WBCT-based markers possibly can help the surgeon in decision-making regarding the appropriate surgical strategy (eg, osteotomies vs realignment arthrodesis). However, prospective studies are necessary to confirm the utility of the proposed parameters in the treatment of PCFD. LEVEL OF EVIDENCE: Level III, case-control study.

High Reliability for Semiautomated 3D Measurements Based on Weightbearing CT Scans.

BACKGROUND: A reliable assessment of the ankle using weightbearing radiography remains challenging. Semiautomated 3-dimensional (3D) measurements derived from weightbearing computed tomography (WBCT) scans may provide a more reliable approach. METHODS: Thirty healthy individuals without any foot and ankle disorder were analyzed. We assessed 6 widely used ankle parameters (4 angles and 2 distances) using either semiautomated 3D (based on WBCT scans) or traditional 2-dimensional (2D; based on conventional radiographs) measurements. The reliability and discrepancy between both techniques were compared using intraclass correlation coefficients and the Bland-Altman method. RESULTS: Five of 6 variables showed a lower reliability when derived from 2D measurements. The mean of 3 variables differed between the techniques: the 3D technique assessed that the talonavicular coverage angle was 18.9 degrees higher, the axial talocalcaneal angle was 5.5 degrees higher, and the talocalcaneal overlap was 3.7 mm lower when compared with 2D measurements. CONCLUSION: Semiautomated 3D measurements derived from WBCT scans provide more reliable information on ankle alignment compared with 2D measurements based on weightbearing radiographs. Future studies may show to what extent these parameters could contribute to current diagnostic algorithms and treatment concepts. LEVEL OF EVIDENCE: Not applicable.

Ankle Range of Motion Following 3-Component Total Ankle Arthroplasty.

BACKGROUND: Although surgeons have argued that preserving motion at the level of the ankle joint may be crucial for the long-term success in the treatment of end-stage ankle osteoarthritis, there is little evidence regarding the potential of total ankle arthroplasty (TAA) to increase ankle range of motion (ROM). In addition, the effect of a percutaneous heel cord lengthening (HCL) during TAA on ankle motion is poorly understood. METHODS: A total of 357 primary TAAs treated with a 3-component device (336 patients, mean age 62.6 [24-85] years) performed between May 2003 and November 2017 were retrospectively analyzed. Sagittal ankle ROM was assessed according to a previously published protocol preoperatively (PreOP), 1 year postoperatively (PostOP), and at the last available follow-up (LastFU). Pain assessed on a visual analog scale (VAS) was assessed at the same time points. The effect of a percutaneous HCL on ankle ROM and VAS for pain was also evaluated. RESULTS: Preoperative ankle ROM increased from mean 31.3 (0-69) to 33.9 (5-65) degrees 1 year postoperatively (P = .0002) and decreased to 31.9 (5-70) degrees at the LastFU (P = .007). Percutaneous HCL showed no effect on ankle ROM development after TAA (P = .141). Ankle ROM improvement after TAA (PreOP to LastFU) was higher in ankles with lower preoperative ankle motion (P < .0001). A lower ankle ROM at the last follow-up tended to be associated with a higher pain level (P = .056). CONCLUSION: Although ankles with a lower preoperative sagittal ROM gained motion, the current data suggest that TAA has little potential to increase the preoperative available ankle motion. In some patients with a high preoperative ankle ROM, a slight decrease of ankle motion was observed postoperatively. Patients with limited ankle motion at long-term follow-up tended toward experiencing higher pain levels. The short- and long-term effect of a percutaneous HCL on ankle ROM following TAA was minimal. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

3D Assessment in Posttraumatic Ankle Osteoarthritis.

BACKGROUND: Auto-generated 3-dimensional (3D) measurements based on weightbearing cone-beam computed tomography (CT) scan technology may allow for a more accurate hind- and midfoot assessment. The current study evaluated the reliability and clinical relevance of such measurements in patients with posttraumatic end-stage ankle osteoarthritis. METHODS: Seventy-two patients treated at our institution for posttraumatic end-stage ankle osteoarthritis, with available weightbearing conventional radiographs and a cone-beam CT scan, were analyzed. Twenty healthy individuals aged between 40 and 70 years served as controls. Seven variables were measured on weightbearing conventional radiographs (2D) and compared to 3D measurements that were based on reconstructions from weightbearing cone-beam CT scans. The reliability of each measurement was calculated and subgroups formed according to commonly observed deformities. RESULTS: Inter- and intraobserver reliability was superior for 3D compared to 2D measurements. The accuracy of 3D measurements performed on osteoarthritic ankles was similar to 3D measurements performed on healthy individuals. Thirty-three of the 72 included patients (46%) evidenced an inframalleolar compensation of a supramalleolar/intra-articular ankle deformity (78% = varus compensation; 22% = valgus compensation), whereas 24 of those 72 patients (33%) showed no compensation or a further increase of a supramalleolar/intra-articular ankle deformity (67% = varus deformity; 33% = valgus deformity). CONCLUSION: Auto-generated 3D measurements of the hind- and midfoot were found to be reliable in both healthy individuals and patients with posttraumatic end-stage ankle osteoarthritis. Such measurements may be crucial for a detailed understanding of the location and extent of hindfoot deformities, possibly impacting decision making in the treatment of end-stage ankle osteoarthritis. LEVEL OF EVIDENCE: Level III, comparative study.

Axial Rotational Alignment in Mobile-Bearing Total Ankle Arthroplasty.

BACKGROUND: The presence of an interface between the tibial component and the polyethylene insert (PI) in mobile-bearing total ankle arthroplasty (TAA) may allow the talus to adapt its axial position according to the patient's anatomy. However, little is known about differences of the axial talar rotation between patients following mobile-bearing TAA. Therefore, the aim of this study was to assess the relative axial rotation between the talar and tibial component intraoperatively and after a minimum follow-up of 3 years following mobile-bearing TAA. METHODS: The relative axial rotation between the talar and the tibial component was measured intraoperatively in a cohort of 58 patients who underwent mobile-bearing TAA. In addition, it was measured on weightbearing computed tomography (CT) scans in 48 patients after a mean of 6.3 (3.0-16.3) years following mobile-bearing TAA. The pre- and postoperative alignment of the ankle joint/tibial component and hindfoot assessed on conventional radiographs was correlated with the intra- and postoperatively determined relative axial rotation of the talar and tibial component. RESULTS: The mean intra- and postoperative axial talar component position was 1.7 (range, 14 internal to 14 external) and 1.4 (range, 12 internal to 20 external) degrees toward internal when compared to the tibial component (P = .960). The preoperative sagittal alignment of the distal tibia correlated with the intraoperatively determined relative axial rotation between the talar and the tibial component (P = .019). CONCLUSION: The wide range of the relative axial rotation between the tibial and talar component suggests that it is crucial to allow the talus to intraoperatively find a position that corresponds to the patient's individual anatomy. The fact that the range of axial rotation was similar after a minimum of 3 years measured under weightbearing conditions suggests that structural changes of the osteoarthritic ankle may be the main determining factors for the axial rotational position of the talus. Our findings improve current understanding of proper implant position during TAA. In addition, the current study provides a reliable method to assess the postoperative axial position of the prosthesis components. The high interindividual variability of the relative rotation between the tibial and talar component in the axial plane suggests that axial malpositioning following TAA may be a more common issue than currently expected. Our findings may help to improve the assessment of patients with persistent pain following TAA. LEVEL OF EVIDENCE: Level III, comparative series.

Syndesmotic Overload in 3-Component Total Ankle Replacement.

BACKGROUND: Mobile-bearing total ankle replacement (TAR) potentially enables motion at the tibial implant-polyethylene insert (PI) interface. Such additional freedom of movement may overload periarticular ligaments and subsequently result in coronal translation of the talus. The aim of this study was to assess whether syndesmotic overload affects clinical and radiographic outcomes following mobile-bearing TAR and whether tibiofibular fusion is an effective treatment option. METHODS: Thirty-one patients who underwent revision surgery for syndesmotic overload after mobile-bearing TAR were retrospectively analyzed. Clinical and radiographic outcomes were assessed before and after index TAR, preoperatively to revision surgery, and at the last follow-up after revision surgery. Computed tomography scans were also analyzed. RESULTS: Ankles with lateral talar translation prior to revision surgery were about 10 times more likely to have valgus tibial implant position (P = .003). A wide tibiofibular distance at the level of the syndesmosis after index TAR was associated with an increased hindfoot moment arm at revision surgery (P = .025). Decrease of PI height at revision surgery and a PI fracture were evident in 10 (32%) and 4 (13%) cases, respectively. Talar cyst formation at revision surgery was evident in 12 (39%) cases. Tibiofibular fusion was effective in restoring function of the replaced ankle and providing pain relief. CONCLUSION: Syndesmotic overload impaired clinical and radiographic outcomes after mobile-bearing TAR. Proper implant positioning and additional realignment procedures may prevent overload of periarticular soft tissue structures after mobile-bearing TAR. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Effect of age on outcome and revision in total ankle arthroplasty.

AIMS: To assess the effect of age on clinical outcome and revision rates in patients who underwent total ankle arthroplasty (TAA) for end-stage ankle osteoarthritis (OA). METHODS: A consecutive series of 811 ankles (789 patients) that underwent TAA between May 2003 and December 2013 were enrolled. The influence of age on clinical outcome, including the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score, and pain according to the visual analogue scale (VAS) was assessed. In addition, the risk for revision surgery that includes soft tissue procedures, periarticular arthrodeses/osteotomies, ankle joint debridement, and/or inlay exchange (defined as minor revision), as well as the risk for revision surgery necessitating the exchange of any of the metallic components or removal of implant followed by ankle/hindfoot fusion (defined as major revision) was calculated. RESULTS: A significant improvement in the AOFAS hindfoot score and pain relief between the preoperative assessment and the last follow-up was evident. Age had a positive effect on pain relief. The risk for a minor or major revision was 28.7 % at the mean follow-up of 5.4 years and 11.0 % at a mean follow-up of 6.9 years respectively. The hazard of revision was not affected by age. CONCLUSION: The clinical outcome, as well as the probability for revision surgery following TAA, is comparable between younger and older patients. The overall revision rate of the Hintegra total ankle is comparable with other three component designs. TAA should no longer be reserved for low demand elderly patients, but should also be recognized as a viable option for active patients of younger age. Cite this article: Bone Joint J 2020;102-B(7):925-932.