Tibiotalar Angle Research Articles

Clinical study of Cross-Union surgery for treatment of pseudarthrosis of tibia with neurofibromatosis type 1 in children

To evaluate the effectiveness of Cross-Union surgery for the treatment of pseudarthrosis of the tibia (PT) with neurofibromatosis type 1 (NF1). The clinical data of 8 children of PT with NF1 who met the selection criteria between January 2018 and December 2023 was retrospectively analyzed. There were 5 boys and 3 girls, and the operative age ranged from 1.8 to 13.3 years with a median age of 3.5 years. According to Paley classification, there were 2 cases of type 2a, 2 cases of type 3, 2 cases of type 4a, and 2 cases of type 4c. There were 5 cases of first operation and 3 cases of re-fracture after previous operation. Six cases had leg length discrepancy before operation, and 2 of them had shortening over 2.0 cm. Except for 1 case of ankle fusion, the other 7 cases had ankle valgus. Preoperative coronal/sagittal angulation was recorded. Postoperative pseudarthrosis healing and refracture were observed. Leg length discrepancy and tibiotalar angle were measured and recorded before operation and at last follow-up. Inan imaging evaluation criteria was used to evaluate the imaging effect. All patients were followed up 12-37 months (mean, 23.5 months). One pseudarthrosis failed to heal at 12 months after operation and healed at 3 months after reoperation, while the other pseudarthrosis healed with a healing rate of 87.5% and a healing time of 4-8 months (mean, 5.3 months). No refracture occurred during the follow-up. At last follow-up, there were 2 new cases with leg length discrepancy, which were 0.7 cm and 1.3 cm, respectively. In 2 cases with the leg length discrepancy more than 2.0 cm before operation, the improvement was from 4.1 cm and 12.6 cm to 2.1 cm and 9.0 cm, respectively. There was no significant difference in leg length discrepancy between pre- and post-operation in 8 cases ( P>0.05). At last follow-up, 6 patients still had ankle valgus, and there was no significant difference in the tibiotalar angle between pre- and post-operation ( P>0.05); the tibial coronal/sagittal angulation significantly improved when compared with that before operation ( P<0.05). According to Inan imaging evaluation criteria, 1 case was good, 6 cases were fair, and 1 case was poor. Cross-Union surgery is an effective method for the treatment of PT with NF1 in children, can achieve good bone healing results with a low risk of re-fracture. The surgery may not have significant effects on leg length discrepancy and ankle valgus, and further treatment may be required.

Anterior or Posterior Tibial Tendon Transfer to the Peroneus Tertius for Equinovarus Deformity.

Equinovarus deformity correction was performed by soft tissue release and bone deformity correction, and tendon transfer to maintain deformity correction. Because of the high complication rate of tendon fixation methods, partial or total anterior tibial tendon or posterior tibial tendon transfer to the peroneus tertius tendon was reported. The purpose of this study was (i) to review the results of this tendon transfer technique after release and correction of talipes equinovarus, and (ii) to analyze the complication of this technique. Between February 2017 and May 2022, 176 patients (210 feet) with equinus and/or varus foot and ankle deformities underwent anterior or posterior tibial tendon transfer to the peroneus tertius in our institute. Preoperative and postoperative foot and ankle range of motion (passive and active) were checked. The postoperative radiographic assessment included antero-posterior (AP), lateral, and hindfoot alignment radiographs. Preoperative and postoperative lateral tibio-talar, talo-calcaneal, talo-first metatarsal, tibial-sole angles, hindfoot alignment, and anterior subluxation of the talus were checked. The American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, and visual analog scale (VAS) were used to assess pain. Paired Student's t-test was used to compare the clinical scores and radiographic angles before the operation and at the last follow-up. The mean age of the patients was 23.27 ± 13.44 years (range, 3-69 years). The mean follow-up time was 25.56 ± 16.37 months (range, 12-68 months). There were significant differences between the preoperative and postoperative measurements of the lateral tibio-talar angle, lateral talo-calcaneal angle, lateral talo-first metatarsal angle, lateral tibial-sole angle, and hindfoot alignment (p < 0.001). There was significant difference between the preoperative and postoperative AOFAS and VAS scores (p < 0.001). The early complications included infection in one patient, skin necrosis in two patients, and plantar numbness in three patients. The late complications included pin infection in three patients, tibio-talar joint compression in four patients, forefoot pain in two patients, toe flexion in two patients, and plantar numbness in one patient. There were three cases of complications (1.43%) related to the transferred tendons. Tibialis anterior or posterior tendon transfer to the peroneus tertius is a safe and effective method for equinovarus deformity correction. It yielded excellent outcomes that produced high patient satisfaction and few complications.

Optimizing Outcomes in Distal Tibial Deformity Correction: The Role of Supramalleolar Osteotomy with Computer-assisted Hexapod External Fixator.

Distal tibial deformities can significantly impact patients if left uncorrected, often leading to pain, alterations in gait, and the eventual development of post-traumatic arthritis. The criteria for surgical correction in these patients continues to be a subject of debate, while supramalleolar osteotomy (SMO) is an effective method for correcting distal tibial deformities. The purpose of this study was to evaluate and compare the clinical results of SMO using internal fixation or using computer-assisted hexapod external fixator in the treatment of distal tibial deformity. A retrospective study was conducted on 290 patients who underwent SMO between June 2015 and January 2023. Forty-four patients met the inclusion and exclusion criteria. Among the participants, 19 underwent SMO combined with a computer-assisted hexapod external fixator, while 25 received SMO with plate and screw internal fixation. The tibial anterior surface (TAS) angle, tibial lateral surface (TLS) angle, the tibiotalar (TT) angle and the talocrural (TC) angle were assessed on weight-bearing X-ray films. Functional assessments were performed according to the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score. The study followed patients for an average duration of 31.7 ± 15.3 months, with a range from 12 to 67 months. Successful bone union was achieved in all cases. For patients treated with the computer-assisted hexapod external fixator, significant improvements were observed: the mean deviation in sagittal plane deformity parameters decreased from 14.3 ± 10.4 degrees preoperatively to 2.8 ± 3.8 degrees postoperatively (p < 0.05). Similarly, coronal plane deformity parameters showed a reduction from 25.9 ± 22.5 degrees preoperatively to 5.9 ± 11.0 degrees postoperatively (p < 0.05). The AOFAS ankle-hindfoot score improved markedly from 66.0 ± 14.9 to 86.1 ± 11.7 points (p < 0.05). For patients undergoing internal fixation, the absolute difference in coronal plane parameters improved from 15.4 ± 12.6 degrees preoperatively to 3.7 ± 3.4 degrees postoperatively (p < 0.05). A significant enhancement in AOFAS ankle-hindfoot score was also noted, increasing from 68.3 ± 14.3 points to 79.4 ± 13.5 points (p < 0.05). There were no significant differences in gender, side, follow-up time, postoperative deviation of deformity, pre- or postoperative AOFAS between the two groups. In conclusion, comprehensive preoperative planning of SMO combined with either internal fixation or a hexapod external fixator for treating distal tibial deformities can achieve satisfactory outcomes. The utilization of a computer-assisted hexapod external fixator facilitates a gradual and precise correction process, which proved to be an effective and relatively safe method.

Influence and risk factors of lateral hinge fracture on early effectiveness of supramalleolar osteotomy

To evaluate the influence of lateral hinge fracture (LHF) on the early effectiveness of supramalleolar osteotomy (SMO) and to explore the related risk factors for LHF. A total of 39 patients (39 feet) with varus-type ankle osteoarthritis treated with SMO between January 2016 and December 2022 were analyzed retrospectively. There were 10 males and 29 females, aged from 41 to 71 years (mean, 57.7 years). According to Takakura stage, there were 6 feet in stage Ⅱ, 19 feet in stage Ⅲa, and 14 feet in stage Ⅲb. The LHF was recognized by the immediate postoperative X-ray film. The osteotomy healing time and the changes of pain visual analogue scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, tibial anterior surface angle (TAS), tibial lateral surface angle (TLS), and tibiotalar angle (TT) before and after operation were compared between patients with and without LHF. The age, gender, affected side, body mass index, Takakura stage, preoperative VAS score, preoperative AOFAS score, preoperative TAS, preoperative TLS, preoperative TT, SMO correction angle, osteotomy distraction, distance from medial osteotomy to ankle joint line (MD), and distance from lateral osteotomy to ankle joint line (LD) were compared between with and without LHF patients, and further logistic regression analysis was used to screen the risk factors of LHF during SMO. All patients were followed up 12-54 months (mean, 27.1 months). During operation, 13 feet developed LHF (group A) and 26 feet did not develop LHF (group B). X-ray film reexamination showed that 1 patient in group A complicated with tibial articular surface cleft fracture had delayed osteotomy and healed successfully after plaster fixation; the osteotomy of other patients healed, and there was no significant difference in healing time between the two groups ( P>0.05). At last follow-up, there were significant differences in VAS score, AOFAS score, TAS, TLS, and TT of the two groups when compared with preoperative ones ( P<0.05), but there was no significant difference in the changes of above indicators before and after operation between the two groups ( P>0.05). The differences in SMO correction angle, osteotomy distraction, and LD between with and without LHF patients were significant ( P<0.05), and further logistic regression analysis showed that excessive LD was the risk factor of LHF during SMO ( P<0.05). Too high or too low lateral hinge position during SMO may lead to LHF, but as long as appropriate treatment and rehabilitation measurements are taken, the early effectiveness is similar to that of patients without LHF.

THE ROLE OF ROTATION IN TOTAL ANKLE ARTHROPLASTY

BackgroundThe importance of total ankle replacement (TAR) implant orientation in the axial plane is poorly understood with major variation in surgical technique of implants on the market. Our aims were to better understand the axial rotational profile of patients undergoing TAR.MethodsIn 157 standardised CT Scans of end-stage ankle arthritis patients planning to undergo primary TAR surgery, we measured the relationship between the knee posterior condylar axis, the tibial tuberosity, the transmalleolar axis(TMA) and the tibiotalar angle. The foot position was measured in relation to the TMA with the foot plantigrade. The variation between medial gutter line and the line bisecting both gutters was assessed.ResultsThe mean external tibial torsion was 34.5±10.3°(11.8–62°). When plantigrade the mean foot position relative to the TMA was 21±10.6°(0.7–38.4°) internally rotated. As external tibial torsion increased, the foot position became more internally rotated relative to the TMA(pearson correlation 0.6;p&lt; 0.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA(pearson correlation −0.4;p&lt; 0.01). The mean difference between the medial gutter line and a line bisecting both gutters was 4.9±2.8°(1.7°-9.4°). More than 51% of patients had a difference greater than 5°. The mean angle between the medial gutter line and a line perpendicular to the TMA was 7.5°±2.6°(2.8°-13.7°).ConclusionThere is a large variation in rotational profile of patients undergoing TAR, particularly between the medial gutter line and the transmalleolar axis. Surgeon designers and implant manufacturers need to develop consistent methods to guide surgeons towards judging appropriate axial rotation of their implanton an individual basis. We recommend careful clinical assessment and CT scanspre-operatively to enable the correct rotation to be determined.

Comparing Rates of Radiographic Baseplate Loosening Between Cement and Cementless INFINITY Total Ankle Prostheses.

Total ankle replacement is indicated for end-stage ankle osteoarthritis. Periprosthetic radiolucency, from separation between the bone and implant, is suggested to be indicative of potential prosthesis failure risk. Anchoring implants with cement may mitigate this. This study aimed to compare rates of periprosthetic radiolucency between patients with cement-affixed and cementless implants. A retrospective analysis was performed on 28 patients who underwent total ankle replacement with the INFINITY Total Ankle System (Wright Medical, Memphis, Tennessee) implant between January 2016 and May 2022. Anteroposterior, mortise, and lateral ankle X-rays were reviewed by 2 independent reviewers for tibiotalar angle, talar tilt, and periprosthetic radiolucency. The Wilcoxon rank-sum test and chi-square test were performed. The incidence of periprosthetic radiolucency at the most recent follow-up did not significantly differ between cement and cementless groups (57.1% in both groups, P = 1.0). Follow-up tibiotalar and talar tilt angles were not significantly different (P > .51 for all comparisons). Patients with cemented implants had a similar incidence of periprosthetic radiolucency compared with patients with cementless prostheses. Understanding of long-term clinical outcomes will help inform optimal operative approaches for ankle prostheses. Therapeutic, Level III, Retrospective cohort study.

Effect of a compression staple on correction of varus deformity during arthroscopic ankle arthrodesis

BackgroundArthroscopic ankle arthrodesis (AAA) has become popular because of its higher rate of bone union, lower invasiveness, and shorter hospital stays compared to those of open arthrodesis. However, postoperative malalignment is often observed for severe varus deformity, which can cause nonunion, pain, and adjacent joint arthrosis. A compression staple can provide a persistent, strong compressive force on the bone surface. This study aimed to clarify the difference in alignment correction in AAA by comparing a compression staple and screws fixation with screws-only fixation pre- and postoperatively. MethodsSeventy ankles in 67 patients undergoing AAA were retrospectively reviewed. AAA with three screws through the distal tibia was performed in 53 ankles, and 17 ankles underwent AAA with a compression staple and two screws. After the preparation of the joint surface arthroscopically, patients in the S group had three canulated cancellous screws inserted through the medial tibia. Patients in the CS group had a compression staple placed at the lateral aspect of the tibiotalar joint and two screws inserted through the medial side. Clinical scores and pre-and postoperative alignment on plain radiographs were compared between the two procedures. ResultsThere were no significant differences in the pre-and postoperative Japanese Society for Surgery of the Foot scale. One ankle in the S group exhibited nonunion. There were no significant differences in talar tilt and tibiotalar angles between the groups. The tibial plafond angle in the CS group was significantly lower than that in the S group (p < 0.05). Postoperatively, talar tilt and tibiotalar angles on the coronal image, and the lateral tibiotalar angle in the CS group were significantly lower than those in the S group (p < 0.05). ConclusionAAA with a compression staple and two-screw fixations could obtain more optimal alignments than AAA with screw-only fixation, even in cases with severe varus deformity.

Early results of combined total ankle total talus replacement in the revision setting

BackgroundRevision of failed total ankle replacement (TAR) is challenging and associated with increased morbidity. Given the increased popularity of TAR in treating end-stage ankle arthritis (ESAA), viable revision options are needed. The objective of this case series is to present a minimum 2-year clinical and radiographic outcomes of patient-specific custom 3D-printed total ankle total talus (TATR) prostheses in this unique subset of patients. Methods19 participants with ESAA and failed primary TAR who underwent TATR by a single surgeon at our institution from 2019 to 2021 were retrospectively identified. All participants were indicated for revision of primary STAR implant (Stryker, Kalamazoo, MI) and underwent replacement with 3D-printed titanium implants based on preoperative CT analysis (Additive Orthopaedics, Little Silver, NJ). Custom components included a mobile-bearing total talus and stemmed tibial system, performed through an anterior approach. Pre- and postoperative patient-reported outcomes were assessed using the Patient Reported Outcomes Measurement Information System (PROMIS). Pre- and postoperative implant alignment was assessed using medial distal tibial angle (MDTA) and tibiotalar angle (TTA) on anteroposterior, and sagittal tibial angle (STA) on lateral weight-bearing plain films. ResultsThe average patient age was 60.6 (range, 39–77) years, with an average follow-up of 37.9 (range, 25.3–57.5) months. There was statistically significant improvement in all PROMIS domains. Short-term survivorship was 100%, with two participants (11.0%) requiring reoperation for postoperative complications: one underwent open reduction internal fixation of the tibia for a periprosthetic fracture, and another underwent medial gutter debridement and tarsal tunnel release for recurrent pain. There were no significant differences in pre- versus postoperative radiographic alignment measured by MDTA (89.9 vs 86.4), TTA (89.7 vs 88.1), or STA (85.2 vs 85.3). ConclusionCustom 3D-printed TATR is a promising option for revision TAR. There was significant short-term improvement in pain and physical function, with excellent short-term survivorship and an acceptable postoperative complication rate.

Simple Talectomy is a Beneficial Surgical Procedure for Talipes Equinovarus and Other Severe Neuromuscular Foot Deformities

Noninvasive techniques are gold standard to redress Severe Neuromuscular Foot Deformity (SNFD). However, simple talectomy may be considered to obtain a stable, plantigrade, pain-free foot. We present a 10-year follow-up accessing radiological correction rates, functional outcomes, complications, and patient satisfaction. This retrospective case series evaluated talectomies in 2012 to 2022. Simple talectomy was combined with Steinman pin fixation of calcaneus to tibia for approximately 6 weeks. Diagnoses primarily included arthrogryposis multiplex congenita and cerebral palsy. Indications were pain, wounds/pressure marks, severe rigidity, and residual/recurrent deformity. The primary outcome was radiological correction. Tibiotalar angle (TiTa) and tibiocalcaneal angle (TiCa) were measured on mediolateral projections. Secondary outcomes were functional scores of pain/deformity graded as good, fair or poor. Furthermore, validated patient-reported outcome measures, that is, EQ-5D-5L and the Scoliosis Research Society-30 Questionnaire (2 items) assessed health-related quality of life and patient satisfaction. Nineteen talectomies in 11 patients were analyzed. Mean follow-up was 62 months (range 9-112 months). Mean TiTa was 137° (95%CI 128;146). TiCa improved significantly: Mean difference -24° (95%CI -44;-5, p = .02). All feet became plantigrade and pain-free with no skin issues. Functional outcomes were graded as 9/19 good, 10/19 fair and 0/19 poor. Parents/primary caregivers were mainly satisfied. Perceived health was 54 (95%CI 34;75) out of 100 on a visual analogue scale, emphasizing complex medical conditions. In conclusion, simple talectomy is a suitable salvage procedure for SNFD.

Defining and Differentiating Congenital Vertical Talus and Congenital Oblique Talus: It's Not Primarily About the Talus.

Congenital vertical talus (CVT) and congenital oblique talus (COT) are rocker-bottom foot deformities that have similar names and no objective definitions. This has led to confusion for practitioners, as well as scientific challenges for researchers. Our goal was to provide objective radiographic criteria to define and differentiate CVT and COT. We evaluated 62 pairs of maximum dorsiflexion and plantar flexion lateral radiographs of infant feet that had been clinically diagnosed with CVT. The dorsiflexion tibiotalar angle, the plantar flexion talus-first metatarsal angle, and the plantar flexion foot center of rotation of angulation (foot-CORA) were measured using transparent overlay tools. Freehand measurements were made on a subset of 10 pairs of radiographs to confirm clinical applicability. Nine contralateral pairs of radiographs of normal feet were measured for comparison. Specific values for the radiographic measurements were identified that, together, reliably differentiated the shapes of rocker-bottom feet with CVT, COT, and flexible flatfoot with a short tendo-Achilles (FFF-STA), as well as the shape of the normal foot. More severe and rigid rocker-bottom foot deformities were diagnosed with CVT. Less severe and more flexible deformities were diagnosed with COT. CVT, COT, FFF-STA, and normal feet can be reliably differentiated using 2 angular measurements and 1 bone position measurement on dorsiflexion and plantar flexion lateral radiographs. Our data indicated that the differentiation of CVT and COT is based primarily on the rigidity of the navicular dislocation rather than the verticality of the talus. The data further supported the proposition that COT is a foot deformity along a spectrum of valgus/eversion deformities of the hindfoot that requires early treatment. Application of these diagnostic criteria should lead to clinical studies that identify a specific treatment, treatment outcome, and prognosis for each deformity. Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Increased medial talar tilt may incite ankle pain and predispose ankle osteoarthritis after correction of severity of knee varus deformity among patients undergoing bilateral total knee arthroplasty: a prospective observation

PurposePatients with varus knee osteoarthritis usually compensate at the ankle and typically walk with hindfoot valgus alignment. As the neutral weight-bearing axis of the lower limbs is restored with Total Knee Arthroplasty (TKA), ankle and hindfoot biomechanics also acutely change. This study aims to investigate whether any ankle clinical-radiographical changes occur as a result of bilateral mechanical TKA in patients with bilateral Osteoarthritis knee at a minimum follow-up of 6 months.MethodsThe prospective observational study included 61 patients (122 knees) undergoing simultaneous bilateral TKA (mechanical alignment). Tibio-talar angle(TTA), tibial Anterior Surface angle (TAS), lateral distal tibial angle (LDTA), talar-tilt angle (TT), anatomical talocrural angle (aTC), ground surface and distal tibial plafond angle (GP), ground surface and an upper surface of talus angle (GT)and tibial plateau and tibial plafond angle (PP) were measured on long-film radiographs to look for changes in the ankle, whereas functional assessment was done using American Foot and Ankle Society (AOFAS), Foot and Ankle Disability Index (FADI), and Forgotten Joint (FJS-12) scores. Patients were sub-grouped based on the Hip-Knee-Ankle (HKA) axis, and the effect of the severity of knee varus on the ankles after TKA was also analyzed. The minimum follow-up was 6 months.ResultsA significant decrease in the tibial plateau-tibial plafond (PP), ground-tibial plafond (GP), and ground-talar dome (GT) angles was noted after TKA (p-value < 0.05). Postoperative functional parameters were comparable to the preoperative status except for FADI, which significantly improved (p-value-0.03). Sub-group analysis based on the severity of knee varus (HKA) revealed GT to be most significantly reduced (p-value-0.036), while the talar tilt (TT) increased (p-value-0.044). Functional outcomes of the ankles clinically improved with the correction of severe knee varus after TKA. At a mean follow-up of 13.2 months post-TKA, 7 out of 61 (11.4%) patients complained of post-TKA ipsilateral ankle pain.ConclusionMechanically aligned bilateral TKA in severe varus deformity of the knee significantly decreases the GT angle but increases the varus tilt of the talus with lateral talar incongruency and under-coverage. Although the acute correction of severe knee varus deformity aligns the tibia more neutrally, resulting in an overall clinically evident improvement in ankle functional outcome, the increased varus talar tilt remains a deep concern.Level of EvidenceProspective, observational, comparative study Level II.

Biomechanical Effects of Subtalar Joint Fusion and Medial Ligament Reconstruction in Simulated Progressive Collapsing Foot Deformity.

The purpose of this study is to investigate the biomechanical effect of medial displacement calcaneal osteotomy (MDCO), subtalar joint fusion (SF), and medial ligament reconstruction (MLR: deltoid-spring ligament) in a severe flatfoot model. We hypothesized that (1) combination of MDCO and SF improves the tibiotalar and foot alignment in severe progressive collapsing foot deformity (PCFD) cadaver model. (2) However, if a residual valgus heel alignment remains after MCDO and SF, it can lead to increased medial ligament strain, foot malalignment, and tibiotalar valgus tilt, which will be mitigated by the addition of MLR. Ten fresh-frozen cadaveric foot specimens were used to create a severe flatfoot model. The foot alignment changes, including the talo-first metatarsal angle in the axial and sagittal planes, subtalar angle, and tibiotalar angle in the coronal plane, were measured. The angles were measured at the initial condition, after creating the severe flatfoot model, and after each successive reconstructive procedure in the following order: (1) MDCO, (2) SF, and (3) MLR. Tibiotalar valgus tilt was decreased with the MDCO procedure: 4.4 vs 1.0 degrees (P = .04). Adding in situ SF to the MDCO led to increased tibiotalar tilt to 2.5 degrees was different from the initial condition (P = .01). Although the tibiotalar valgus tilt was significantly decreased after adding the MLR to the MDCO/SF procedure compared with the severe flatfoot model (0.8 vs 4.4 degrees, P = .03), no significant difference in the tibiotalar valgus tilt was observed between MDCO/SF and MDCO/SF with MLR. Our results demonstrated that MDCO significantly improved forefoot abduction and medial arch alignment, with no significant additional improvement observed with addition of SF. Following SF, a residual valgus heel alignment can contribute to subsequent tibiotalar valgus tilt. The addition of MLR did not show significantly decreased tibiotalar valgus tilt following SF. Residual valgus heel alignment after subtalar joint fusion in the surgical treatment of PCFD can lead to increased medial ligament strain. Although MLR might be considered for providing medial stability, it may not necessarily prevent the development of tibiotalar valgus tilt.

Current Trends in Total Ankle Replacement.

Ankle arthritis can result in significant pain and restriction in range of motion. Total ankle replacement (TAR) is a motion-preserving surgical option used as an alternative to total ankle arthrodesis to treat end-stage ankle arthritis. There are several generations of TAR techniques based on component design, implant material, and surgical technique. With more recent TAR implants, an attempt is made to minimize bone resection and mirror the native anatomy. There are more than 20 implant devices currently available. Implant survivorship varies among prosthesis types and generations, with improved outcomes reported with use of the more recent third- and fourth-generation ankle implants. Pre- and postoperative assessments of TAR are primarily performed by using weight-bearing radiography, with weight-bearing CT emerging as an additional imaging tool. Preoperative assessments include those of the tibiotalar angle, offset, and adjacent areas of arthritis requiring additional surgical procedures. US, nuclear medicine studies, and MRI can be used to troubleshoot complications. Effective radiologic assessment requires an understanding of the component design and corresponding normal perioperative imaging features of ankle implants, as well as recognition of common and device-specific complications. General complications seen at radiography include aseptic loosening, osteolysis, hardware subsidence, periprosthetic fracture, infection, gutter impingement, heterotopic ossification, and syndesmotic nonunion. The authors review several recent generations of TAR implants commonly used in the United States, normal pre- and postoperative imaging assessment, and imaging complications of TAR. Indications for advanced imaging of TAR are also reviewed. ©RSNA, 2023 Supplemental material is available for this article. Test Your Knowledge questions for this article are available through the Online Learning Center.

Changes in clinical outcomes and alignment of the ipsilateral knee and ankle after supramalleolar osteotomy in patients with varus osteoarthritis of the ankle: a short-term follow-up study.

The purpose of this study was to investigate the changes in clinical outcomes and alignment of the ipsilateral knee and ankle in patients with varus ankle osteoarthritis after supramalleolar osteotomy (SMO). We retrospectively reviewed 23 patients (24 ankles) with Takakura II, IIIa and IIIb ankle osteoarthritis treated with SMO between May 2017 and March 2022. The radiologic parameters of ankles contained medial distal tibial angle (TAS), tibiotalar angle (TT), tibial lateral surface (TLS), tibial plafond inclination (TPI) and talar inclination (TI). The radiologic parameters of knees contained medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), the knee joint line orientation relative to ground (G-KJLO) and WBL. Hip-knee-ankle angle (HKA) was also collected. The Takakura system was used for evaluating the ankle osteoarthritis and the Kellgren-Lawrence (KL) system was used for evaluating the knee osteoarthritis. Clinical evaluation of the ankle joints contained American Orthopedic Foot and Ankle Society (AOFAS), range of motion (ROM) and visual analogue scale (VAS). Clinical evaluation of the knee joints contained Japanese Orthopaedic Association Scores (JOA), ROM, VAS. The mean follow-up times were 20.3 ± 7.3months (range 12-38). According to the radiologic evaluation, the TAS increased from preoperative 84.7° ± 2.0° to 91.2° ± 1.8° at the last follow-up (P < 0.001). The TPI and TI decreased from 4.4° ± 4.2° and 11.0° ± 5.2° to 0.1° ± 4.7° and 4.1° ± 4.8° (P < 0.001 for both). The TT angel improved from 9.5° ± 4.1° to 4.9° ± 3.3° (P < 0.001). No significant differences were found regarding MPTA, JLCA, G-KJLO, knee WBL and HKA (P > 0.05 for all). The Takakura stage improved after SMO (P < 0.001) whilst the KL stage maintains the similar lever (P > 0.05). According to the clinical evaluation, the AOFAS significantly increased from 67.5 ± 10.6 to 88.5 ± 9.3 and the VAS of the ankle decreased from 4.7 ± 1.6 to 1.2 ± 1.1, whilst there were no changes on VAS and even the JOA and knee ROM after SMO (P > 0.05 for all). SMO can alleviate the symptoms of varus ankle osteoarthritis and delay the time for ankle replacement or arthrodesis by redistributing the abnormal stress of the ankle and restoring the congruence of the tibiotalar joint. In addition, it did not induce the clinical symptoms of knee without compromising lower limb alignment or knee joint line orientation in the short term. Level IV case series.

Comparing Rates of Radiographic Baseplate Loosening Between Cement and Cementless INFINITY Total Ankle Prostheses

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement has risen in popularity as the contemporary treatment-of-choice for end-stage ankle osteoarthritis. INFINITY™ Total Ankle System (Stryker, Kalamazoo, MI) is one of the most frequently used ankle prostheses. Prior studies established positive functional outcomes; however, aseptic baseplate loosening has reported to occur in approximately one-third of patients. Aseptic baseplate loosening is seen radiographically either as shift in talar or tibial components or evidence of periprosthetic lucency. Aseptic baseplate loosening with persistent pain defines prosthesis failure, thus an indication for early surgical revision. Implementing bone cement may fixate and stabilize prostheses, potentially reducing incidence of aseptic baseplate loosening. This study aimed to determine if patients with cemented INFINITY total ankle prostheses had different incidence of aseptic baseplate loosening than those with cementless prostheses. Methods: Patients who underwent total ankle arthroplasty using the INFINITY total ankle prosthesis system between January 2016 and May 2022 (n = 28) were retrospectively identified using keyword search for “infinity” and Current Procedural Terminology (CPT) code 27702. Fourteen patients had prostheses affixed with cement, and fourteen patients had prostheses that were not cemented. Preoperative, immediate postoperative, and most recently available anteroposterior (AP), mortise, and lateral ankle X- rays were reviewed. Tibiotalar angle, talar tilt, and presence of visible postoperative lucency were assessed independently by two reviewers. Wilcoxon rank-sum test on quantitative variables and chi-square test on categorical variables were performed with 0.05 significance level. Results: Inter-rater reliability was above 94% for all measurements. Comparing the cemented to cementless sample group, difference in average age (59.5 years vs. 56.5 years, p=0.32) and sex (57.1% vs. 50.0% female, p=0.70) were not statistically significant. Pre-operative and immediate post-operative tibiotalar and talar tilt angles were not statistically significantly different between cement and cementless groups (p&gt;0.31 for all comparisons). Only one patient in the cement group had evidence of periprosthetic lucency in the immediate postoperative period. Median follow-up was 362.5 days and 544.5 days in the cement and cementless group, respectively (p=0.52). Follow-up tibiotalar angles and talar tilt angle between cement and cementless groups were not significantly different (p&gt;0.51 for all comparisons). Periprosthetic lucency occurred in 50% of both groups in the follow- up period (p=1.0). Conclusion: Patients with cemented INFINITY total ankle prostheses had equal incidence of aseptic baseplate loosening compared to patients with cementless prostheses. Continuing to examine methods for reducing incidence of baseplate loosening is significant for potentially reducing rate of early prosthesis revision and prosthesis failure, consequently improving quality of life for patients.

Reliability of Cone Bean Weight-Bearing Measurements of the Postoperative Outcome of Total Ankle Arthroplasties and Inter-Method Reliability with Respect to the Weight Bearing x-rays

Category: Ankle Arthritis; Ankle Introduction/Purpose: Postoperative evaluation of the total ankle arthroplasty (TAA) alignment is a fundamental step in measuring the surgical outcome. The current reference standard, weight-bearing x-ray (WBXR), is subject to technical bias. Weight-bearing cone beam computer tomography (WBCT) allows visualization of the complex three-dimensional (3D) structure of the foot under the influence of its deforming forces. A WBCT-based measurement system to assess postoperative outcomes has yet to be validated. The purpose of this study was (1) to measure the surgical outcome of TAA using semiautomatic generated models, (2) to evaluate the agreement levels between two raters, and (3) to evaluate the inter-method reliability with respect to WBXR. Methods: Fifty-five consecutive patients were retrospectively viewed. Two raters independently created a 3D model using dedicated software. Each rater measured six different measurements: α angle tibiotalar angle, hind foot angle (HFA), β angle, γ angle, and Φ angle using a semiautomatic 3D model and one measurement, the tibiatalar ratio (TTR) using WBCT on sagittal view. Measurements were repeated two months apart in the same independent fashion. Results were compared to standard weight- bearing x-rays. Consequently, interobserver, intraobserver, and intermethod agreements were calculated. Results: All seven measurements showed good to excellent interobserver and interobserver reliability. (ICC 0.85-0.95). The intermethod agreement showed good agreement for the γ angle (0.79) moderate agreement levels for the α angle, TTS angle, β angle, and TTR (ICC 0.68, 0.69, 0.70, 0.69 respectively), a poor agreement for the HFA angle (ICC 0.25), and a negative agreement for the φ angle (ICC -0.2). Conclusion: Postoperative analysis of TAA using WBCT demonstrated good to excellent interobserver and intraobserver agreement and can be reliably used. When compared to WBXR, moderate to good agreement was measured for the sagittal and coronal alignment of the components. A poor agreement was measured for the coronal alignment of the hindfoot, and a negative agreement was measured for the axial rotation angle, indicating that the intermethod comparison is unreliable.

Patient Reported Outcomes Before and After Revision Total Ankle Arthroplasty Done In the First Two Years of a Single Surgeons Practice

Category: Ankle Arthritis; Ankle Introduction/Purpose: As Total Ankle Arthroplasty (TAA) volume continues to grow nationally, so is the need for revision TAA surgery. A foot and ankle surgeon fresh out of fellowship is likely to encounter these challenging cases soon after beginning practice. The learning curve for ankle replacement has been demonstrated in multiple studies but no such study exists for revision TAA due to the relative infrequency of this procedure. The experience of one high volume revision TAA surgeon in the first two years after fellowship is reviewed in this study. Radiographic, clinical, and patient reported outcomes are analyzed in this study. Methods: In this IRB approved study, we retrospectively reviewed prospectively collected data on 18 patients who underwent Revision Total Ankle Arthroplasty Surgery from January 1, 2018, to January 1, 2021. Patient-reported outcome (PRO) measures including PROMIS depression, physical function and pain interference CATs taken preoperatively and then at specific post- operative intervals were collected on all patients. Radiographic and clinical results were also reviewed. Patients being revised, whether single stage or two-stage, for infection were excluded. Patients converted from ankle arthrodesis to ankle replacement were omitted. Student t tests, chi-square test, and nonparametric alternatives (p &lt;.05) we used. Results: Eighteen patients ( Average age 65.5, 50% male) underwent revision TAA average follow up 25 months. Aseptic loosening (50%) was the most common cause for revision followed by component malpositioning (28.8%). The Scandanavian Total Ankle Replacement was the most commonly revised implant in this study 83.3%. Radiographic parameters (Tibiotalar angle Tibial component positioning) improved after revision TAA. Average Promis physical function improved from 41.18 pre-op to 47.77 (p.078), depression improved from 57.64 pre-op to 49.67(p .025*), and pain interference improved from 61.3 preop to 50.55 (p .045*) after revision TAA. No differences were seen in any outcome measure with regards to time from fellowship, when assessing for a learning curve. See attached table for complete list of results. Conclusion: Revision TAA is a technically challenging procedure. One which will continue to be more and more common as ankle replacement continues to replace arthrodesis as the preferred treatment for ankle arthritis. This study did not identify a learning curve for revision total ankle arthroplasty. Outcomes were similar independent of time after fellowship the cases occurred. Patient reported outcomes, clinical outcomes, and radiographic outcomes all improved in this cohort after revision TAA.

Weight-Bearing Computed Tomography Evaluation of Acute SER4a Ankle Fractures

Category: Ankle; Trauma Introduction/Purpose: Recent studies have reported cadaveric and early clinical data regarding Weber B supination-external- rotation (SER)4a ankle fractures. SER4a ankle fractures have discordance of the medial clear space (MCS) between weight-bearing (WB) and gravity stress (GS) radiographs, showing instability on the GS view which normalizes with WB. Unfortunately, evaluation of the medial clear space only provides a two-dimensional evaluation of a three-dimensional structure. Prior cadaveric research has shown significant decreases in the tibiotalar joint contact area with only 1 mm of displacement of the talus. The purpose of this study is to utilize weight-bearing computed tomography (WBCT) to evaluate differences in the tibiotalar joint contact area and rotational alignment in patients with acute SER4a ankle fractures compared to their contralateral uninjured ankle. Methods: Adult patients presenting within ten days of injury with an isolated Weber B fibula fracture and a normal MCS ( &lt; 5 mm) on injury radiographs were evaluated with weight-bearing and gravity stress radiographs. Patients determined to have isolated Weber B SER4a ankle fractures (GS positive but WB negative radiographs) and no history of injury to the contralateral ankle were included. The ability to place equal weight on both extremities was confirmed by standing on side-by-side scales. WBCT scans were obtained of both the healthy and injured ankles. The images were evaluated using Disior Bonelogic (Paragon28, Helsinki, Finland) software to calculate the tibiotalar joint contact area, axial tibiotalar rotation, and talocrural angle. An a priori power analysis was performed with six patients needed. Results: Five out of ten patients have been enrolled in the study to date (3 females, 2 males, average age 52.4). Preliminary data show an average 4.3% (standard deviation (SD) 4.9) increase in tibiotalar joint contact area between the injured and uninjured extremity. The average difference in axial tibiotalar angle is 3.6 (SD 6.9) degrees of internal rotation of the injured ankle. The talocrural in the injured and uninjured extremity have an average difference of 0.062 (SD 1.8) degrees. Conclusion: This study provides the first in vivo evaluation of the joint contact area changes seen in SER4 ankle fractures. Although limited in sample size, the results demonstrate that SER4a ankle fractures do not have decreased tibiotalar joint contact area relative to the healthy, uninjured side. The trend towards increased surface area in the injured ankles is hypothesized to be a result of the increased reliance on joint congruency with injury to the fibula and deltoid.

The morphology of osseous structure in subtalar joint with chronic ankle instability

BackgroundOsseous structures have been demonstrated as risk factors for chronic ankle instability (CAI). Previously, the researchers only focused on the osseous structures of ankle, but ignored the osseous structures of subtalar joint(STJ). Accordingly, the aim of our study was to investigate the morphological characteristics of STJ osseous structures in CAI. Methods52 patients with CAI and 52 sex- and age- matched control subjects were enrolled from The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University. The lateral radiographs of ankle in weight-bearing were used to compare the diversity of the two groups. Specifically, The Length of calcaneus, Calcaneal facet height and Absolute foot height, Böhler's angle, Gissane's angle, Calcaneal inclination angle, Talocalcaneal angle, Tibiotalar angle, Tibiocalcaneal angle, Talar-horizontal angle, talar declination angle, facet inclination angle were gauged in the two groups. ResultsThe Böhler's angle, Calcaneal inclination, Talocalcaneal angle, Tibiotalar angle, Talar-horizontal angle, Talar declination angle, Facet inclination angle and Absolute foot height of CAI group were significantly higher than normal control group (P < 0.05). There were no significant differences in Gissane's angle, Tibiocalcaneal angle, Length of calcaneus and Calcaneal facet height between patients with CAI and normal controls (P > 0.05). ConclusionsThe osseous structures of STJ in CAI patients are different from normal people in morphology. Therefore, we should pay more attention to the changes of STJ anatomical parameters in the diagnosis and prevention of CAI. Level of evidenceⅢ.

Short-term effectiveness of INBONE TM Ⅱ total ankle prosthesis arthroplasty in the treatment of moderate to severe varus-type ankle arthritis

To investigate the short-term effectiveness of INBONE TM Ⅱ total ankle prosthesis arthroplasty in the treatment of moderate to severe varus-type ankle arthritis. The clinical and radiographic data of patients with moderate to severe varus-type ankle arthritis, who were admitted between May 2017 and November 2021 and treated with total ankle arthroplasty (TAA) using INBONE TM Ⅱ prosthesis, was retrospectively analyzed. A total of 58 patients (58 ankles) met the selection criteria and were included in the study. Among them, there were 24 males and 34 females, with an average age of 62.6 years (range, 41-85 years). According to the preoperative tibiotalar angle (TTA), the patients were divided into a moderate varus group (group A, TTA 5°-15°, n=34) and a severe varus group (group B, TTA>15°, n=24). There was no significant difference in gender, side, etiology, preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score, ankle dorsiflexion, plantarflexion, and total range of motion, and tibial lateral surface angle (TLS) between the two groups ( P>0.05). Yet the patients in group A were younger than group B, the degrees of oesteoarthritis (Takakura stage) and ankle pain [visual analogue scale (VAS) score] were milder, and the TTA, talar tilt angle (TT), hindfoot alignment angle (HAA) were smaller while the tibial articular surface angle (TAS) was larger, showing significant differences ( P<0.05). The pre- and post-operative VAS score, AOFAS score, the occurrence of early and late complications, the radiographic parameters of the ankle (TTA, TAS, TT, HAA, TLS), ankle dorsiflexion, plantarflexion, and total range of motion were recorded and compared. All patients were followed up 19-72 months, with an average of 38.9 months. Compared with the preoperative data, the VAS score of all patients significantly decreased ( P<0.05); the AOFAS score, ankle dorsiflexion range of motion, and total range of motion significantly increased ( P<0.05); and the TTA, TAS, TT, HAA, and TLS significantly improved at last follow-up ( P<0.05); but there was no significant difference in plantarflexion range of motion ( P>0.05). Early complications occurred in 13 patients, and only 1 patient underwent revision surgery due to a larger size of the talar component. At last follow-up, there was no significant difference in the difference of clinical parameters before and after operation between the two groups ( P>0.05); there was a significant difference in the difference of other radiographic parameters ( P<0.05) except TLS. No significant difference in the incidence of complications between the two groups was found ( P>0.05). TAA using the INBONE TM Ⅱtotal ankle prosthesis is an effective treatment for moderate or severe varus-type ankle arthritis, and good clinical and radiographic results can be obtained. Correcting bony deformities and balancing soft tissue are the keys to successful surgery.