Compensatory Motion of the Subtalar Joint Following Tibiotalar Arthrodesis: An in Vivo Dual-Fluoroscopy Imaging Study

Ankle and hindfoot motion of healthy adults during running revealed by dynamic biplane radiography: Side-to-side symmetry, sex-specific differences, and comparison with walking

This study aimed to characterize ankle and hindfoot kinematics of healthy men and women during overground running using biplane radiography, and to compare these data to those previously obtained in the same cohort during overground walking. Participants ran across an elevated platform at a self-selected pace while synchronized biplane radiographs of their ankle and hindfoot were acquired. Motion of the tibia, talus, and calcaneus was tracked using a validated volumetric model-based tracking process. Tibiotalar and subtalar 6DOF kinematics were obtained. Absolute side-to-side differences in ROM and kinematics waveforms were calculated. Side-to-side and sex-specific differences were evaluated at 10 % increments of stance phase with mixed model analysis. Pearson correlation coefficients were used to assess the relationship between stance-phase running and walking kinematics. 20 participants comprised the study cohort (10 men, mean age 30.8 ± 6.3 years, mean BMI 24.1 ± 3.1). Average absolute side-to-side differences in running kinematics waveforms were 5.6°/2.0 mm or less at the tibiotalar joint and 5.2°/3.2 mm or less at the subtalar joint. No differences in running kinematics waveforms between sides or between men and women were detected. Correlations were stronger at the tibiotalar joint (42/66 [64 %] of correlations were p < 0.05), than at the tibiotalar joint (38/66 [58 %] of correlations were p < 0.05). These results provide a normative reference for evaluating native ankle and hindfoot kinematics which may be informative in surgical or rehabilitation contexts. Sex-specific differences in ankle kinematics during overground running are likely not clinically or etiologically significant. Associations seen between walking and running kinematics suggest one could be used to predict the other.

Tibiotalar nailing using an antegrade intramedullary tibial nail: a salvage procedure for unstable distal tibia and ankle fractures in the frail elderly patient

AIM

This article describes the technique of tibiotalar nailing performed using an antegrade tibial nail for salvage of distal tibia and ankle fractures in elderly patients.

MATERIALS AND METHODS

We report indications, surgical technique, and the clinical outcomes and complication rate in our series to date. A retrospective review was performed at our level 1 major trauma centre. Patient demographics, comorbidities, and 12-month post-operative course were collected. Fractures were classified using the OTA/AO and modified Gustilo-Anderson classification. Fifteen patients underwent the procedure. We present data with a minimum 12-month follow-up. The median age of the patients in this cohort was 83 years (range, 51-102). Five patients were diabetic. Six patients (6/15; 40%) presented with an open fracture.

RESULTS

At final follow-up, fourteen patients reported painless walking and had returned to baseline activity.

CONCLUSION

This technique may serve as a salvage procedure, with indications similar to those for tibio-talar-calcaneal arthrodesis. Indications would include non-constructible pilon fractures, comminuted intra-articular fractures in low-demand patients, or patients at high risk of wound complications.

LEVEL OF CLINICAL EVIDENCE

3.

Influence of Joint Line Level on Clinical Outcomes and Range of Motion in Total Ankle Arthroplasty

BACKGROUND

Ankle arthritis leads to an elevated joint line compared to the nonarthritic ankle, as measured by the "joint line height ratio" (JLHR). Previous work has shown that the JLHR may remain elevated after total ankle arthroplasty (TAA). However, the clinical impact of this has yet to be determined. This study assessed the correlation between postoperative JLHR, post-TAA range of motion (ROM), and 1-year Patient-Reported Outcome Measurement Information System (PROMIS) scores.

METHODS

A retrospective review of 150 patients who underwent primary TAA was performed. Preoperative and postoperative JLHR, as well as postoperative dorsiflexion, plantarflexion, and total ROM, was calculated on weightbearing radiographs at a minimum of 1-year follow-up. Correlation between JLHR, post-TAA ROM, and 1-year PROMIS scores was investigated using Pearson correlation and multiple linear regression models. Interobserver reliability for the JLHR was also calculated.

RESULTS

Interobserver reliability for the JLHR was excellent (r = 0.98). Mean (SD) JLHR changed from 1.66 (0.45) to 1.55 (0.26) after TAA (P < .001), indicating that the joint line was lowered after TAA. An elevated joint line was correlated with decreased post-TAA dorsiflexion (r = -0.26, P < .001), total ROM (r = -0.18, P = .025), and worse 1-year PROMIS physical function (r = -0.22, P = .046), pain intensity (r = 0.22, P = .042), and pain interference (r = 0.29, P = .007). There was no correlation between the JLHR and post-TAA plantarflexion (r = -0.025, P = .76). Regression analysis identified a 0.5-degree reduction in post-TAA dorsiflexion with each 0.1-unit increase in JLHR (Coeff. = -5.13, P = .005).

CONCLUSION

In this patient cohort, we found that an elevated joint line modestly correlated with decreased postoperative dorsiflexion, total ROM, and worse 1-year PROMIS scores. These data suggest that effort likely should be made toward restoring the native joint line at the time of TAA. In addition, future studies investigating the clinical outcomes after TAA may consider including a measure of joint line height, such as the JLHR, because we found it was associated with patient-reported outcomes.

LEVEL OF EVIDENCE

Level III, retrospective review of prospectively collected data.

The Center-Center Image Closely Approximates Other Methods for Syndesmosis Reduction Clamp Placement

BACKGROUND

The optimal placement for a syndesmosis reduction clamp remains an open question. This study compared the center-center axis, which localizes clamp placement using only an internally rotated lateral ankle X-ray, with other common approaches, whose accuracy can only be confirmed using computed tomography (CT).

METHODS

Bone models of anatomically aligned (n = 6) and malreduced (n = 48) limbs were generated from CT scans of cadaveric specimens. Four axes for guiding clamp placement (center-center, centroid, B2, and trans-syndesmotic) were then analyzed, using digitally reconstructed radiographs derived from the bone models. Each axis' location was defined using angle-height pairs that describe axis orientation along the full anatomical region where syndesmosis fixation occurs.

RESULTS

In anatomically aligned limbs, the center-center axis was located on average (±95% CI [confidence interval]), 0.64° (±0.50°) internal rotation, 1.03° (±0.73°) internal rotation, and 2.09° (±7.29°) external rotation from the centroid, B2, and trans-syndesmotic axes, respectively. Fibular displacement altered the magnitude of limb rotation needed to identify the center-center axis.

CONCLUSION

The center-center technique is a valid method that closely approximates previously described methods for syndesmosis clamp placement without using CT, and the magnitude of C-arm rotation needed to transition from a talar dome lateral to a center-center view may be a potential method for assessing syndesmosis reduction.

LEVELS OF EVIDENCE

Level III: Retrospective comparative study.

4D-foot analysis on effect of arch support on ankle, subtalar, and talonavicular joint kinematics

BACKGROUND

It has been difficult to study the effects of arch support on multiple joints simultaneously. Herein, we evaluated foot and ankle kinematics using a fully automated analysis system, "4D-Foot," consisting of a biplane X-ray imager and two-dimensional‒three-dimensional registration, with automated image segmentation and landmark detection tools.

METHODS

We evaluated the effect of arch support on ankle, subtalar, and talonavicular joint kinematics in five healthy female volunteers without a clinical history of foot and ankle disorders. Computed tomography images of the foot and ankle and X-ray videos of walking barefoot and with arch support were acquired. A kinematic analysis using the "4D-Foot" system was performed. The ankle, subtalar, and talonavicular joint kinematics were quantified from heel-strike to foot-off, with and without arch support.

RESULTS

For the ankle joint, significant differences were observed in dorsi/plantarflexion, inversion/eversion, and internal/external rotation in the late midstance phase. The dorsi/plantarflexion and inversion/eversion motions were smaller with arch support. For the subtalar joint, a significant difference was observed in all the dynamic motions in the heel-strike and late midstance phases. For the talonavicular joint, significant differences were observed in inversion/eversion and internal/external rotation in heel-strike and the late midstance phases. For the subtalar and talonavicular joints, the motion was larger with arch support. An extremely strong correlation was observed when the motion of the subtalar and talonavicular joints was compared for each condition and motion.

CONCLUSIONS

The results indicated that the arch support decreased the ankle motion and increased the subtalar and talonavicular joint motions. Additionally, our study demonstrated that the in vivo subtalar and talonavicular joints revealed a strong correlation, suggesting that the navicular and calcaneal bones were moving similarly to the talus and that the arch support stabilizes the ankle joint and compensatively increases the subtalar and talonavicular joint motions.

Automatic anatomical foot and ankle coordinate toolbox

Accurate analysis of bone position and orientation in foot and ankle studies relies on anatomical coordinate systems (ACS). Reliable ACSs are necessary for many biomechanical and clinical studies, especially those including weightbearing computed tomography and biplane fluoroscopy. Existing ACS approaches suffer from limitations such as manual input, oversimplifications, or non-physiological methods. To address these shortcomings, we introduce the Automatic Anatomical Foot and Ankle Coordinate Toolbox (AAFACT), a MATLAB-based toolbox that automates the calculation of ACSs for the major fourteen foot and ankle bones. In this manuscript, we present the development and evaluation of AAFACT, aiming to provide a standardized coordinate system toolbox for foot and ankle studies. The AAFACT was evaluated using a dataset of fifty-six models from seven pathological groups: asymptomatic, osteoarthritis, pilon fracture, progressive collapsing foot deformity, clubfoot, Charcot Marie Tooth, and cavovarus. Three analyses were conducted to assess the reliability of AAFACT. Firstly, ACSs were compared between automatically and manually segmented bone models to assess consistency. Secondly, ACSs were compared between individual bones and group mean bones to assess within-population precision. Lastly, ACSs were compared between the overall mean bone and group mean bones to assess the overall accuracy of anatomical representation. Statistical analyses, including statistical shape modeling, were performed to evaluate the reliability, accuracy, and precision of AAFACT. The comparison between automatically and manually segmented bone models showed consistency between the calculated ACSs. Additionally, the comparison between individual bones and group mean bones, as well as the comparison between the overall mean bone and group mean bones, revealed accurate and precise ACSs calculations. The AAFACT offers a practical and reliable solution for foot and ankle studies in clinical and engineering settings. It accommodates various foot and ankle pathologies while accounting for bone morphology and orientation. The automated calculation of ACSs eliminates the limitations associated with manual input and non-physiological methods. The evaluation results demonstrate the robustness and consistency of AAFACT, making it a valuable tool for researchers and clinicians. The standardized coordinate system provided by AAFACT enhances comparability between studies and facilitates advancements in foot and ankle research.

Subtalar Arthrodesis in Patients With Prior Tibiotalar Arthrodesis for Posttraumatic Osteoarthritis

BACKGROUND

The tibiotalar arthrodesis for end-stage ankle osteoarthritis is a surgical procedure that leads to a modification of the kinematics of the adjacent joints and may result in the development of secondary osteoarthritic degeneration of the subtalar joint. It has previously been observed that subtalar arthrodesis in this context shows a lower fusion rate than isolated subtalar arthrodesis. This retrospective study reports the results of subtalar joint arthrodesis with previous ipsilateral tibiotalar arthrodesis and suggests some factors that may compromise the fusion of the joint.

METHODS

Between September 2010 and October 2021, 15 arthrodeses of the subtalar joint with screw fixation were performed in 14 patients, with a fusion of the ipsilateral tibiotalar joint. Fourteen of 15 cases used an open sinus tarsi approach, 13 were augmented with iliac crest bone graft, and 11 had supplemental demineralized bone matrix (DBM). The outcome variables were fusion rate, time to fusion, and revision rate. Fusion was assessed by radiographs and computed tomography scan.

RESULTS

Twelve of the 15 subtalar arthrodeses (80%) fused at the first attempt with an average fusion time of 4.7 months.

CONCLUSION

In this limited retrospective case series, compared to the fusion rate of isolated subtalar arthrodesis reported in the literature, the rate of subtalar fusion in the presence of an ipsilateral tibiotalar arthrodesis was found to be lower.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Short-Term Risk Factors for Subtalar Arthrodesis After Primary Tibiotalar Arthrodesis

While adjacent joint arthritis is a recognized long-term downside of primary tibiotalar arthrodesis (TTA), few studies have identified risk factors for early subtalar arthrodesis (STA) after TTA. This study aims to identify the risk factors for STA within the first few years following TTA. All patients older than 18 years undergoing TTA between 2008 and 2016 were identified retrospectively. Demographic data and comorbidities were collected alongside prior operative procedures, postoperative complications, and subsequent STA. Pre-and postoperative Kellgren-Lawrence osteoarthritis grade of the subtalar joint and postoperative radiographic alignment were obtained. A total of 240 patients who underwent primary TTA were included in this study with median follow up of 13.8 months. Twenty patients (8.3%) underwent STA after TTA due to symptomatic nonunion of TTA in 13 (65%), progression of symptomatic subtalar osteoarthritis (OA) in 4 (20%), and symptomatic nonunion of primary TTA combined progressively symptomatic subtalar OA in 2 (10%). Preoperative radiographic subtalar OA severity and postoperative radiographic alignment were not correlated with subsequent STA. Diabetes mellitus, Charcot arthropathy, neuropathy, alcohol use, substance use disorder, and psychiatric disease were significantly associated with having a subsequent STA. The most common postoperative contributing factor for subsequent STA following primary TTA was the salvage of symptomatic ankle nonunion rather than subtalar joint disease. Patients considering an ankle fusion should be counseled of the risk of subsequent STA, especially if they have risk factors that include diabetes, Charcot arthropathy, neuropathy, alcohol use, substance use disorder, or psychiatric disease.

Mechanics and energetics of human feet: a contemporary perspective for understanding mobility impairments in older adults

Much of our current understanding of age-related declines in mobility has been aided by decades of investigations on the role of muscle-tendon units spanning major lower extremity joints (e.g., hip, knee and ankle) for powering locomotion. Yet, mechanical contributions from foot structures are often neglected. This is despite the emerging evidence for their critical importance in youthful locomotion. With rapid growth in the field of human foot biomechanics over the last decade, our theoretical knowledge of young asymptomatic feet has transformed, from long-held views of a stiff lever and a shock-absorber to a versatile system that can modulate mechanical power and energy output to accommodate various locomotor task demands. In this perspective review, we predict that the next set of impactful discoveries related to locomotion in older adults will emerge by integrating the novel tools and approaches that are currently transforming the field of human foot biomechanics. By illuminating the functions of feet in older adults, we envision that future investigations will refine our mechanistic understanding of mobility deficits affecting our aging population, which may ultimately inspire targeted interventions to rejuvenate the mechanics and energetics of locomotion.

Summary Report of the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society's Symposium on Targets for Osteoarthritis Research: Part 2: Treatment Options

This second of a 2-part series of articles recounts the key points presented in a collaborative symposium sponsored jointly by the Arthritis Foundation and the American Orthopaedic Foot & Ankle Society with the intent to survey current treatment options for osteoarthritis (OA) of the foot and ankle. A meeting was held virtually on December 10, 2021. A group of experts were invited to present brief synopses of the current state of knowledge and research in this area. Topics were chosen by meeting organizers, who then identified and invited the expert speakers. Part 2 overviews the current treatment options, including orthotics, non-joint destructive procedures, as well as arthroscopies and arthroplasties in ankles and feet. Opportunities for future research are also discussed, such as developments in surgical options for ankle and the first metatarsophalangeal joint. The OA scientific community, including funding agencies, academia, industry, and regulatory agencies, must recognize the importance to patients of addressing the foot and ankle with improved basic, translational, and clinical research.

LEVEL OF EVIDENCE

Level V, review article/expert opinion.

Total Ankle Replacement Provides Symmetrical Postoperative Kinematics: A Biplane Fluoroscopy Imaging Study

BACKGROUND

In vivo measurements of tibiotalar and subtalar joint motion following TAR are unavailable. Using biplane fluoroscopy, we tested the hypothesis that the prosthetic tibiotalar joint and adjacent subtalar joint would demonstrate kinematic and range of motion differences compared to the contralateral untreated limb, and control participants.

METHODS

Six patients of 41 identified candidates that all underwent unilateral Zimmer TAR (5.4 ± 1.9 years prior) and 6 control participants were imaged with biplane fluoroscopy during overground walking and a double heel-rise activity. Computed tomography scans were acquired; images were segmented and processed to serve as input for model-based tracking of the biplane fluoroscopy data. Measurements included tibiotalar and subtalar kinematics for the TAR, untreated contralateral, and control limbs. Statistical parametric mapping quantified differences in kinematics throughout overground walking and the double heel-rise activity.

RESULTS

Patients with this TAR performed walking and heel-rise activities symmetrically with no significant kinematic differences at the tibiotalar and subtalar joints between limbs. Compared to control participants, patients exhibited reduced dorsi/plantarflexion range of motion that corresponded to decreased peak dorsiflexion, but only in the late stance phase of walking. This reduction in tibiotalar dorsi/plantarflexion range of motion in the TAR group became more apparent with double heel-rise activity.

CONCLUSION

Patients with a Zimmer TAR had symmetric kinematics during activities of walking and double heel-rise, but they did exhibit minor compensations in tibiotalar kinematics as compared to controls.

CLINICAL RELEVANCE

The lack of significant kinematic compensation at the subtalar joint may explain why secondary subtalar osteoarthritis is reported as being relatively uncommon in patients with some TAR designs.

Acute Hindfoot Nailing for Ankle Fractures: A Systematic Review of Indications and Outcomes

OBJECTIVES

To assess the complication rate of hindfoot nailing of acute fractures involving the tibiotalar joint, and mortality, patient-reported outcome measures, and return to preinjury activities.

DATA SOURCES

MEDLINE; EMBASE.

STUDY SELECTION

A systematic literature search for articles in English was completed using MEDLINE and EMBASE databases on April 23, 2020. Original research articles that assessed patients with acute intra-articular fractures of the ankle joint (malleolar ankle fractures and/or pilon fractures) that were treated with a locked hindfoot intramedullary nail, inserted retrograde through the plantar surface of the foot, were selected for inclusion. Case reports (≤4 patients), studies with nonlocked implants, and non-English studies were excluded.

DATA EXTRACTION AND SYNTHESIS

A validated data extraction form was used, which included study demographics (authors, journal, date of publication, and study design), patient characteristics, implant type, and reported outcomes. Risk of bias for each included study was evaluated using the Institute of Health Economics Quality Appraisal Checklist for case series and the Risk of Bias in randomized trials tool, where appropriate. The best evidence was summarized and weighted mean values were provided when appropriate.

RESULTS

Ten case series and one randomized controlled trial were included. The overall quality of studies was poor with considerable bias. The majority of studies included elderly patients (weighted mean age 75.5 years) with diabetes (42% of patients). Overall complication rate was 16% with an 8% major complication rate (deep infection, malunion, nonunion, implant failure) and an overall infection rate of 6.2%. Pooled mortality rate was 27% with fracture union rates from 88% to 100%. Mean proportion of patients able to return to preinjury level of activity was 85%.

CONCLUSIONS

Hindfoot nailing of acute ankle and pilon fractures in elderly patients and patients with diabetes is associated with complication rates comparable with other methods of fixation. Issues with elimination of subtalar joint motion and implant complications secondary to poor implant fixation persist. The literature to date has composed of primarily Level IV studies with considerable bias. Further research is necessary to clarify the role of hindfoot nailing of acute ankle and pilon fractures.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Gait Characteristics in Youth With Transverse Myelitis

Background

Transverse myelitis (TM) in childhood is a rare disorder characterized by the presence of spinal cord inflammation. Gait difficulty in children with TM is common; however, there is a paucity of literature regarding quantitative assessment of gait in children and adolescents with TM.

Objectives

To characterize gait patterns in a cohort of ambulatory children with TM and age-matched, typically developing peers in order to better understand the functional mobility of patients diagnosed with childhood TM.

Methods

This was a retrospective study of 26 ambulatory pediatric patients with a confirmed diagnosis of TM who had undergone three-dimensional, instrumented gait analysis (3D-IGA) at 3 years of age or older. A group of 38 typically developing children served as a control group.

Results

Gait in children with TM was characterized by moderate kinematic deviations as measured by the Gait Deviation Index (GDI) and a crouched gait pattern (p < .001), increased anterior pelvic tilt (p < .001), decreased motion at the knees (p < .001), and a wider base of support (foot progression angle, p < .001). The TM group had a slower walking speed (p < .001), shorter strides (p < .001), and an increased stance phase compared to controls.

Conclusion

Our study results showed moderate kinematic deviations quantified by the GDI. Overall, the gait pattern in the TM population tested had greater hip and knee flexion with wider foot progression angle. Identification of gait characteristics in children with TM is the first step in predicting changes in gait pattern as they mature over time, which may ultimately allow for targeted intervention to maintain their ambulatory function.

Converting Ankle Arthrodesis to a Total Ankle Arthroplasty

Several articles in the literature discuss the positive results of converting a painful ankle fusion to an ankle replacement. Our results confirm that in well-selected cases a conversion to a total ankle replacement is not only possible, but also significantly improves quality of life and reduces pain. The outcome of a total ankle replacement after an ankle fusion depends to a degree on the method of fusion. Less destructive fusion that is arthroscopic has better results than conventional transfibular open fusions. Absence of a fibula should be an absolute contraindication for a conversion.

Assignment of local coordinate systems and methods to calculate tibiotalar and subtalar kinematics: A systematic review

The introduction of biplane fluoroscopy has created the ability to evaluate in vivo motion, enabling six degree-of-freedom measurement of the tibiotalar and subtalar joints. Although the International Society of Biomechanics defines a standard method of assigning local coordinate systems for the ankle joint complex, standards for the tibiotalar and subtalar joints are lacking. The objective of this systematic review was to summarize and appraise the existing literature that (1) defined coordinate systems for the tibia, talus, and/or calcaneus or (2) assigned kinematic definitions for the tibiotalar and/or subtalar joints. A systematic literature search was developed with search results limited to English Language from 2006 through 2020. Articles were screened by two independent reviewers based on title and abstract. Methodological quality was evaluated using a modified assessment tool. Following screening, 52 articles were identified as having met inclusion criteria. Methodological assessment of these articles varied in quality from 61 to 97. Included articles adopted primary methods for defining coordinate systems that included: (1) anatomical coordinate system (ACS) based on individual bone landmarks and/or geometric shapes, (2) orthogonal principal axes, and (3) interactive closest point (ICP) registration. Common methods for calculating kinematics included: (1) joint coordinate system (JCS) to calculate rotation and translation, (2) Cardan/Euler sequences, and (3) inclination and deviation angles for helical angles. The methods each have strengths and weaknesses. This summarized knowledge should provide the basis for the foot and ankle biomechanics community to create an accepted standard for calculating and reporting tibiotalar and subtalar kinematics.

Healthy ankle and hindfoot kinematics during gait: Sex differences, asymmetry and coupled motion revealed through dynamic biplane radiography

The aims of this study were to compare male versus female and dominant versus non-dominant kinematics in the ankle and hindfoot, and to characterize coupled motion between the subtalar and tibiotalar joints during the support phase of gait. Twenty healthy adults walked on a laboratory walkway while synchronized biplane radiographs of the ankle and hindfoot were collected at 100 frames/s. A validated tracking technique was used to measure tibiotalar and subtalar kinematics. Differences between male and female range of motion (ROM) were observed only in tibiotalar (AP and ML) and subtalar (ML) translation (all differences<1 mm and all p < 0.04). Statistical parametric mapping identified differences between kinematics waveforms of males and females in tibiotalar translation (AP and ML) and eversion, and subtalar ML translation. No differences between dominant and non-dominant sides were observed in ROM or kinematics waveforms. The average absolute side-to-side difference in the kinematics waveforms was 4.1° and 1.5 mm or less for all rotations and translations, respectively. Tibiotalar plantarflexion was coupled to subtalar inversion and eversion during the impact and push-off phases of stance (r = 0.90 and r = 0.87, respectively). This data may serve as a guide for evaluating ankle kinematics waveforms, ROM, symmetry, and restoration of healthy coupled motion after surgical intervention or rehabilitation. The observed kinematics differences between males and females may predispose females to higher rates of ankle and knee injury and suggest sex-dependent ankle reconstruction techniques may be beneficial.

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.