Hindfoot Joints Research Articles

Bilateral Foot Pain-Middle Distance Runner

HISTORY: A 14-year-old female middle-distance athlete presented with a history of unilateral (right) foot pain, diagnosed as a navicular stress fracture which was managed non-surgically and made a full clinical recovery. Nine months later she sustained a suspected traumatic spring ligament injury on the opposite side, with subsequent recurrence of pain in the right foot due to overload from the non-weight bearing management of the left foot injury. She therefore presented with bilateral athletics-related foot pain, one-sided apparently traumatic in nature and the other an overload injury. PHYSICAL EXAMINATION: On clinical examination she was noted to have bilateral mild cavus feet with an antalgic gait pattern. Right foot: Calf and Achilles tendon did not reveal any abnormalities (Silfverskiold negative). Ankle was asymptomatic. The hindfoot joints were mobile and non-tender. There was significant tenderness over the talar navicular bone (”N” spot). The mid and forefoot examination did not reveal any abnormalities. The foot was neurovascularly intact. Left foot: Calf and Achilles tendon did not reveal any abnormalities (Silfverskiold negative). The ankle was asymptomatic. The hindfoot joints were mobile and non-tender. There was once again significant tenderness over the talar navicular bone with mild swelling. The spring ligament was not tender. The mid and forefoot examination did not reveal any abnormalities. The foot was neurovascularly intact. DIFFERENTIAL DIAGNOSIS: Navicular stress fractures, tendinopathy of the posterior tibialis tendons, tear of the spring ligament, separation of an accessory navicular TEST AND RESULTS: Imaging with MRI revealed bilateral navicular stress fractures (figure 1), as indicated by bony edema and a fracture line. On close inspection, the navicular fracture lines were visible on x-ray (Figure 2). Further imaging with CT scans confirmed the navicular fractures and demonstrated sclerosis along the fracture borders with no cross trabeculation, suggestive of a non-union (figure 3). FINAL WORKING DIAGNOSIS: Bilateral navicular stress fractures TREATMENT AND OUTCOMES: Open reduction and internal fixation (ORIF) and bone grafting. Postop rehabilitation and graded return to activity. Back to sports with no pain or swelling in her feet 1 year post surgery.

The Effect of CAM Boots on Contact Pressures of the Ankle and Hindfoot Joints

Category:Basic Sciences/Biologics; Ankle; HindfootIntroduction/Purpose:The tall Controlled Ankle Motion (CAM) boot and the short CAM boot are commonly used devices to immobilize the foot and ankle. However, the effect of these devices on joint contact pressures is unknown. The objective of this study is to assess the effect of the tall CAM boot and short CAM boot on contact pressures of the ankle, subtalar, talonavicular, and calcaneocuboid joints. We hypothesize that both the tall CAM boot and short CAM boot will reduce contact pressures of the ankle and hindfoot joints, with the tall CAM boot having the greatest effect.Methods:Eight lower extremity cadaver specimens were mounted on a servohydraulic test frame. The specimens were loaded to 700 N at a cyclical frequency of 1 Hz with the posterior tibial, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and Achilles tendon physiologically tensioned. TekScan (TekScan, Boston, MA) pressure sensors were placed in the ankle, subtalar, talonavicular, and calcaneocuboid joints. In the sagittal plane, the specimens were loaded on a neutral surface, followed by 20o of dorsiflexion. Each specimen served as its own control, with contact pressures measured with no immobilization (control), followed by placement in a short CAM boot and tall CAM boot. In addition, contact pressures in the immobilized limbs were measured at muscle loads both equal to and half of the load applied to the control in order to account for decreased muscle activation during immobilization.Results:There was no difference in the average and peak contact pressures of the ankle, subtalar, talonavicular and calcaneocuboid joints when comparing the short CAM boot to no immobilization at equal tendon loads. The tall CAM boot significantly decreased average and peak contact pressures of the ankle, subtalar, and talonavicular joints when compared to no immobilization. The tall CAM decreased the contact pressures of the talonavicular and subtalar joint to a greater degree than the ankle joint. The reduction in contact pressures was accentuated when the load applied to the tendons was decreased in accordance with diminished muscle activation during immobilization. Neither immobilization device decreased the contact pressures of the calcaneocuboid joint at equal tendon loads. Neither CAM boot changed the center of pressure of any joint.Conclusion:Immobilization in a tall CAM boot decreases contact pressures of the ankle and hindfoot in both a neutral position and in dorsiflexion. A tall CAM boot should be used clinically if the goal of its use is to maximally reduce contact pressures of the ankle and hindfoot. The tall CAM boot is better at reducing the contact pressures of the subtalar and talonavicular joint than the ankle joint.

Preliminary Experience With SPECT/CT to Evaluate Periarticular Arthritis Progression and the Relationship With Clinical Outcome Following Ankle Arthrodesis.

Single photon emission computed tomography combined with computed tomography (SPECT/CT) could potentially aid in diagnosing periarticular arthritis/activity and progression, facilitate effective treatment options, and evaluate the effect surgery has on the clinical outcome of patients with ankle arthritis. The goal of our study was to assess SPECT/CT activity in the ankle and periarticular joints before and after ankle fusion surgery and determine whether it was associated with clinical pain and function scores. Thirty-four patients recruited into this study underwent either arthroscopic or open ankle fusion. X-ray (XR) and SPECT/CT imaging was obtained as well as completion of patient Ankle Osteoarthritis Scale (AOS) and 36-item Short Form Survey (SF-36) questionnaires preoperatively and at 6 months postoperatively. Ankle, subtalar, and talonavicular joint arthritis grading on XR and CT, along with SPECT/CT activity, was evaluated by 2 nuclear medicine radiologists. Data were assessed for normality and analyzed with the appropriate comparative test. P value was set at <.05. Thirty patients (31 ankles) completed follow-up and were analyzed. SPECT/CT activity showed no significant difference in the ankle joint at 6 months postoperatively while periarticular joint activity significantly increased (P < .05). Six months postoperatively, patients had significant improvements in their AOS and SF-36 scores (P < .05). SPECT/CT grading of all joints analyzed, however, was not associated with AOS or SF-36 scores preoperatively or at 6 months postoperatively. In this study, intensity of activity as evaluated by SPECT/CT in periarticular hindfoot joints in patients who had ankle arthrodesis was not associated with clinical/functional scores at 6 months postoperatively. Level IV, diagnostic study.

The Effect of Immobilization Devices on Contact Pressures of the Ankle and Hindfoot

Category:Ankle, HindfootIntroduction/Purpose:The tall Controlled Ankle Motion (CAM) boot and the short CAM boot are commonly used devices to immobilize the foot and ankle. These devices are preferably used instead of casts and splints as they are easily removed, allowing possible wound examination, personal hygiene, and therapeutic exercises. However, the effect of these devices on joint contact pressures is unknown. The aim of this study is to assess the effect of the tall CAM boot and short CAM boot on contact pressures of the ankle, subtalar, talonavicular, and calcaneocuboid joints. We hypothesize that both the tall CAM boot and short CAM boot will reduce contact pressures of the ankle and hindfoot joints, with the tall CAM boot having the greatest effect.Methods:Eight lower extremity cadaver specimens were mounted on a servohydraulic test frame. The specimens were loaded to 700 N at a cyclical frequency of 1 Hz with the posterior tibial, peroneus longus, peroneus brevis, flexor hallucis longus, flexor digitorum longus, and Achilles tendon physiologically tensioned. TekScan (TekScan, Boston, MA) pressure sensors were placed in the ankle, subtalar, talonavicular, and calcaneocuboid joints. In the sagittal plane, the specimens were loaded on a neutral surface, followed by 20o of dorsiflexion. Each specimen served as its own control, with contact pressures measured with no immobilization (control), followed by placement in a short CAM boot and tall CAM boot. In addition, contact pressures in the immobilized limbs were measured at muscle loads both equal to and half of the load applied to the control in order to account for decreased muscle activation during immobilization.Results:There was no difference in the average and peak contact pressures of the ankle, subtalar, talonavicular and calcaneocuboid joints when comparing the short CAM boot to no immobilization at equal tendon loads. The tall CAM boot significantly decreased average and peak contact pressures of the ankle, subtalar, and talonavicular joints when compared to no immobilization. The reduction in contact pressures was accentuated when the load applied to the tendons was decreased in accordance with diminished muscle activation during immobilization. Neither immobilization device decreased the contact pressures of the calcaneocuboid joint at equal tendon loads.Conclusion:Immobilization in a tall CAM boot decreases contact pressures of the ankle and hindfoot in both a neutral position and in dorsiflexion. A tall CAM boot should be used clinically if the goal of its use is to maximally reduce contact pressures of the ankle and hindfoot.

Can Weightbearing CT Scans Be Used to Diagnose Subtalar Joint Instability? A Cadaver Study

Category:Hindfoot, TraumaIntroduction/Purpose:Accurate assessment of subtalar joint stability is difficult. Weightbearing CT (WBCT) scans have increased in popularity among foot and ankle surgeons as it offers an accurate representation of hindfoot joint alignment under weightbearing conditions. However, the clinical utility of this imaging modality to diagnose subtalar joint instability has yet to be investigated. The purpose of this study was to assess the impact of load and torque application on the assessment of subtalar joint instability when using WBCT scans. We hypothesized that load and torque application would improve the ability to identify subtalar joint instability.Methods:Fourteen paired male cadavers (tibial plateau to toe-tip) were included. A radiolucent frame held specimens in a plantigrade position while non-weightbearing and weightbearing CT scans (with and without torque application) were taken. First, intact ankles (Native) were scanned. Second, one specimen from each pair underwent interosseous talo-calcaneal ligament (ITCL) transection (Condition 1A), while the contralateral underwent calcaneo-fibular ligament (CFL) transection (Condition 1B). Third, the lesions were reversed on the same specimens and the remaining intact ITCL or CFL was transected (Condition 2). Finally, the deltoid ligament was transected in all ankles (Condition 3). Two radiographic measurements were performed on the level of the ankle joint (talar tilt [TT], anterior talar translation [ATT]), while the subtalar tilt (STT) was measured at the anterior, middle, and posterior plane of the subtalar joint. Inter- and intra-observer agreement calculations were additionally performed.Results:Weight did not impact most measurements, while the majority of measurements differed significantly within each condition after torque application. Measurements performed at the level of the subtalar joint were more reliable and better predictors for subtalar joint instability compared to measurements performed at the level of the ankle joint. Discrete ITFL, combined ITFL/ CFL, and combined ITFL/ CFL/ deltoid ligament injuries had significantly different STT values than native ankles (Figure 1).Conclusion:Measurements to assess the stability of the subtalar joint should primarily be performed at the level of the subtalar joint rather than at the level of the ankle joint when using WBCT scans. Torque application is crucial for identifying subtalar joint instability, while the application of load should be avoided. Future clinical studies will therefore face substantial technical challenges should they attempt to determine the clinical utility of WBCT scans for assessment of subtalar joint instability.

The influence of selective arthrodesis on three-dimensional range of motion of hindfoot joint: A cadaveric study

BackgroundThe purpose of this study was to measure the three-dimensional range of motion of adjacent, unfused joint or joints after different arthrodesis of hindfoot. MethodsSixteen fresh frozen cadaver feet were immobilized in the non-weight bearing position. The three-dimensional coordinates of markers in tarsal were measured in six directions (involving dorsiflexion-plantarflexion, eversion-inversion, and adduction-abduction) before and after single (involving subtalar joint, talonavicular joint, and calcaneocuboid joint) and double (talonavicular and calcaneocuboid joints) arthrodesis with a three-dimensional coordinate instrument. The range of motion of the joint was calculated with the least square method and matrix transformation. FindingsWe found that the range of motion of joints in all direction was reduced significantly after any combination of selective arthrodesis (all p < 0.001). After arthrodesis of the subtalar joint, the motion of talonavicular joint was reduced by 72%, and that of calcaneocuboid joint by 36%. After arthrodesis of talonavicular joint, the motion of subtalar joint was diminished by 36%, and that of calcaneocuboid joint by 51%. After arthrodesis of calcaneocuboid joint, the motion of subtalar joint was decreased by 21%, and that of talonavicular joint by 42%. After double arthrodesis, the motion of subtalar joint was reduced by 62%. InterpretationIn single arthrodesis, subtalar arthrodesis had the greatest effect on the motion of unfused joints, and the least was the calcaneocuboid arthrodesis. The motion of the subtalar joint was eliminated more than half after double arthrodesis. The data provide a biomechanical rationale to ascertain the clinical implication of the arthrodesis.

Analysis of biomechanical stresses caused by hindfoot joint arthrodesis in the treatment of adult acquired flatfoot deformity: A finite element study

BackgroundTreatments of adult acquired flatfoot deformity in early stages (I–IIa–IIb) are focused on strengthening tendons, in isolation or combined with osteotomies, but in stage III, rigidity of foot deformity requires more restrictive procedures such as hindfoot joint arthrodesis. Few experimental studies have assessed the biomechanical effects of these treatments, because of the difficulty of measuring these parameters in cadavers. Our objective was to quantify the biomechanical stress caused by both isolated hindfoot arthrodesis and triple arthrodesis on the main tissues that support the plantar arch. MethodsAn innovative finite element model was used to evaluate some flatfoot scenarios treated with isolated hindfoot arthrodesis and triple arthrodesis. Results and conclusionsWhen arthrodeses are done in situ, talonavicular seems a good option, possible superior to subtalar and at least equivalent to triple. Calcaneocuboid arthrodesis reduces significantly both fascia plantar and spring ligament stresses but concentrates higher stresses around the fused joint.

Correlation between three-dimensional medial longitudinal arch joint complex mobility and medial arch angle in stage II posterior tibial tendon dysfunction

The purpose of this study was to evaluate correlation between three-dimensional medial longitudinal arch joint complex mobility and medial arch angle in stage II posterior tibial tendon dysfunction flatfoot under loading. CT scans of 15 healthy feet and 15 feet with stage II posterior tibial tendon dysfunction flatfoot were taken both in non- and simulated weight-bearing condition. The CT images of the hindfoot and medial longitudinal arch bones were reconstructed into three-dimensional models with Mimics and Geomagic reverse engineering software. The three-dimensional complex mobility of each joint in the medial longitudinal arch and their correlation with the medial arch angle change were calculated. From non- to simulated weight-bearing condition, the medial arch angle change and the medial longitudinal arch joints mobility were significant larger in stage II posterior tibial tendon dysfunction flatfoot (p<0.05). The eversion of the talocalcaneal joint, the proximal translation of the calcaneus relative to the talus, the dorsiflexion of the talonavicular joint, the dorsiflexion and abduction of the medial cuneonavicular joint, and the lateral translation of the medial cuneiform relative to the navicular, and the dorsiflexion of the first tarsometatarsal joint were all significantly correlated to the medial arch angle change in stage II posterior tibial tendon dysfunction flatfoot (all r>0.5, p<0.05). There is increased mobility in the medial longitudinal arch joints in stage II posterior tibial tendon dysfunction flatfoot and the medial arch angle change under loading causes displacement not only at hindfoot joints but also involve midfoot and forefoot joint.

Ankle and Hindfoot Kinematics of a Next Generation Total Ankle Replacement During Simulated Gait

Category: Ankle Arthritis Introduction/Purpose: Total ankle arthroplasty (TAA) has developed as a viable treatment option for end-stage ankle arthritis. The primary benefit proposed with TAA is that allows for maintained motion of the ankle and hindfoot joint compared to the alternative option of an ankle arthrodesis. Consequently, recent TAA systems have focused on designs that advance kinematic function. Cadaveric gait simulation is a valuable tool for investigating the direct effects of surgical procedures and devices on foot and ankle biomechanics. The objective of this study was to assess whether a next generation TAA system permits normal ankle and hindfoot kinematics using cadaveric gait simulation. Methods: Ten mid-tibia cadaveric specimens were secured to a static mounting fixture relative a six-degree of freedom robotic platform to simulate gait in native-intact and TAA conditions. A force plate was moved relative to the stationary specimen through an inverse tibial kinematic path calculated from in vivo data while extrinsic tendons were actuated using physiologic loads (Figure 1A). Ankle and hindfoot kinematics were measured from reflective markers attached to bones via surgical pins. TAA was performed using a next generation, fixed bearing total ankle system by a fellowship trained foot and ankle surgeon using manufacturer described protocol (Cadence Total Ankle, Integra LifeSciences). Ankle and hindfoot joint kinematics were directly measured using the same kinematic inputs and muscle force as the intact condition. Non-parametric, bias-corrected bootstrapping was used to calculate 95% confidence intervals to compare motion between intact and total ankle replacement conditions. Results: Analyses revealed that no significant difference in average ankle or hindfoot joint kinematics were found between intact and TAA conditions (Figure 1B). This result was consistent in each the ankle, subtalar, and talonavicular joints, and in each plane of motion. Conclusion: This study found that normal kinematics were permitted on average by a next generation, fixed bearing TAA. This finding may indicate that improved functional outcomes following could be expected. However, increased variability and some characteristic differences in the paths of motion throughout stance were observed qualitatively. This report represents an initial analysis of preliminary data, future work will include further analyses and investigation on the influence of factors such as component position and alignment on outcomes. That said, the findings of this study are encouraging and may represent improved kinematic performance in new TAA designs.

Relative to the Subtalar Joint, the Calcaneocuboid Joint has a Greater Range of Motion than the Talonavicular Joint in the Coronal Plane

The objective of this study was to determine the range of motion of the calcaneocuboid and talonavicular joints relative to the subtalar joint in 6 locked midfoot positions and 3 locked subtalar joint positions. Eight fresh‐frozen cadaver specimens were acquired from the Willed Body Program at Louisiana State University Health Sciences Center, Shreveport, LA. Specimens included male and female right and left lower legs transected 20 cm inferior to the knee. The interosseous membrane held the tibia and fibula together and the ankle joint was locked in neutral. The axis finder method developed by Hollister et al. (1993) was used to verify the ankle and hindfoot axes of rotation that had been reported by Inman (1969) and Manter (1941), further validating Hollister's method. The same method was then used to identify the calcaneocuboid and talonavicular midfoot joint axes relative to the subtalar hindfoot joint axis. To measure the axes of rotation, an x‐y‐z coordinate system was fixed to the anterior tibia and used as a reference. The midfoot positions included inversion, eversion, dorsiflexion, plantarflexion, abduction and adduction. The subtalar joint positions included inversion, eversion and neutral. Images (6000 × 4000 pixels) were obtained in the coronal plane for midfoot inversion and eversion, in the sagittal plane for midfoot dorsiflexion and plantarflexion and in the axial plane for midfoot abduction and adduction. A computerized drafting program (Rhinoceros, ver. 5) was used to measure the axis angles. The measurements were analyzed using Independent Sample T‐tests (SPSS, ver. 24), with P &lt;0.05 considered statistically significant.The range of motion of each joint was calculated as the absolute value of the difference in the axis angles between two midfoot positions in each subtalar joint position in the same plane. When the subtalar joint was inverted, the calcaneocuboid joint range of motion was 13.87.33° (mean.D.), whereas the talonavicular joint range of motion was 5.64.03°. When the subtalar joint was everted, the calcaneocuboid and talonavicular joint ranges of motion were 12.74.83° and 7.04.16°, respectively. When the subtalar joint was in neutral position, the calcaneocuboid and talonavicular joint ranges of motion were 15.73.89° and 6.572.12°, respectively. In all three subtalar joint positions, the calcaneocuboid joint range of motion was significantly greater than talonavicular joint range of motion (inversion and eversion, P&lt;0.05; neutral P&lt;0.001). In the sagittal and axial planes, the midfoot ranges of motion for dorsiflexion‐plantarflexion and abduction‐adduction exhibited greater variability and therefore did not differ significantly.Results of this study show that when the midfoot is inverted or everted and the subtalar joint is inverted, everted or in neutral position, the calcaneocuboid joint has a greater range of motion than the talonavicular joint. These results could be used to improve midfoot mobility in prosthetics and for correcting gait cycle abnormalities.Support or Funding InformationResearch supported by the Departments of Cellular Biology and Anatomy and Orthopedics at Louisiana State University Health Sciences Center, Shreveport, LA.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Arthroscopic Ankle Arthrodesis: A 2-15 Year Follow-up Study

The purpose of our study was to determine the results of arthroscopic ankle arthrodesis (AAA) and how the procedure affects adjoining joints and functional scores. Between 1993 and 2013, 116 patients (120 ankles) underwent AAA. Nineteen ankles were lost to follow-up due to death, insufficient radiographic studies, or inability to contact, resulting in 97 patients (101 ankles). Mean age at surgery was 61.1years (range, 35.8-79.6years); mean follow-up was 86months (range, 24-247months). Patients were assessed according to the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle and Hindfoot scale, Ankle Osteoarthritis Scale (AOS), and Foot and Ankle Outcome Score (FAOS) and underwent comprehensive clinical and radiographic examinations. A total of 94.6% of patients achieved ankle fusion on radiographs. Mean AOFAS score was 83.3 (standard deviation [SD], 13.2). Mean modified FAOS score was 87.4 (SD, 10.4). The AOS scoring system showed 75% good/excellent results. According to the Kellgren-Lawrence score and van Dijk osteoarthritis grading scale, 85% and 69% of patients had no change in talonavicular or subtalar grade of osteoarthritis, respectively. There were no cases of deep infection or other serious adverse events. All but 4 patients were able to return to work following AAA. AAA is an effective operation for treating degenerative ankle disease, even in cases of moderate tibiotalar coronal deformity. At a mean of 86months postop, nearly three quarters of our patients had good/excellent functional outcomes. Arthritis found in the adjacent hindfoot joints at the time of tibiotalar fusion appears to be a function of preexisting arthritic change and not directly caused by the tibiotalar fusion. Level IV, therapeutic case series.

Foot and Ankle Joint Biomechanical Adaptations to an Unpredictable Coronally Uneven Surface.

Coronally uneven terrain, a common yet challenging feature encountered in daily ambulation, exposes individuals to an increased risk of falling. The foot-ankle complex may adapt to improve balance on uneven terrains, a recovery strategy which may be more challenging in patients with foot-ankle pathologies. A multisegment foot model (MSFM) was used to study the biomechanical adaptations of the foot and ankle joints during a step on a visually obscured, coronally uneven surface. Kinematic, kinetic and in-shoe pressure data were collected as ten participants walked on an instrumented walkway with a surface randomly positioned ±15 deg or 0 deg in the coronal plane. Coronally uneven surfaces altered hindfoot-tibia loading, with more conformation to the surface in early than late stance. Distinct loading changes occurred for the forefoot-hindfoot joint in early and late stance, despite smaller surface conformations. Hindfoot-tibia power at opposite heel contact (@OHC) was generated and increased on both uneven surfaces, whereas forefoot-hindfoot power was absorbed and remained consistent across surfaces. Push-off work increased for the hindfoot-tibia joint on the everted surface and for the forefoot-hindfoot joint on the inverted surface. Net work across joints was generated for both uneven surfaces, while absorbed on flat terrain. The partial decoupling and joint-specific biomechanical adaptations on uneven surfaces suggest that multi-articulating interventions such as prosthetic devices and arthroplasty may improve ambulation for mobility-impaired individuals on coronally uneven terrain.

Changes in the Ankle Joint and Hindfoot Alignment Following Varus Deformity Correction of the Knee with Total Knee Arthroplasty

Category: Ankle, Hindfoot Introduction/Purpose: Compensatory changes occur in the ankle joint and the subtalar joint of the hindfoot to maintain neutral alignment in coronal plane when varus or valgus deformity is present in the knee joint. The purpose of this study is (1) to analyze how the ankle and hindfoot joint compensate the changes in mechanical axis that occur with varus deformity of the knee, (2) to analyze the changes in ankle and hindfoot joint alignment when mechanical axis alignment is corrected by correction of varus deformity of the knee with total knee arthroplasty (TKA), and (3) to radiographically evaluate the degree of changes in ankle and hindfoot joint alignment according to the degree of varus deformity correction. Methods: 375 knees that underwent TKA with varus deformity were prospectively studied. The degree of varus deformity of the knee joint was measured in standing long leg anteroposterior views taken before and 6 months after TKA. The angle between the ground surface and the superior dome of the talus, and the talar tilt were measured in standing ankle joint anteroposterior views taken before and 6 months after TKA. Preoperative tibial anterior surface angle and tibial lateral surface angle were measured. Hindfoot alignment was evaluated in hindfoot alignment views taken before and 6 months after operation by measuring the heel ratio, the heel angle, and the heel distance. These measurements were used to analyze the change in ankle joint and hindfoot alignment between before and 6 months after varus deformity correction. The relationship between the degree of varus knee correction and the change in ankle joint and hindfoot alignment was also analyzed. Results: The mean mechanical angle of the knee changed from varus 10.6±5.1° before operation to varus 0.1±3.2° after operation, which was statistically significant (P&lt;0.001). The mean correction angle was 10.6±4.6°. Before operation, the mean tibial anterior surface angle was 89.9±3.1° and the mean tibial lateral surface angle was 81.5±2.9°. Talar tilt changed significantly from 0.3±2.0° to 0.0±1.6°, implying a varus change of the ankle joint (P=0.002). All of the evaluated hindfoot alignment parameters demonstrated a significant varus change (P&lt;0.001), as the heel ratio changed from 0.2±0.2 preoperatively to 0.3±0.2 postoperatively (P&lt;0.001), the heel angle changed from 11.4±7.0° preoperatively to 5.0±7.4°postoperatively (P&lt;0.001), and the heel distance changed from 10.5±6.6 mm preoperatively to 6.4±6.4 mm postoperatively (P&lt;0.000). Conclusion: Varus knee deformity tended to be associated with valgus deformity of the ankle joint and hindfoot alignment. Alignment in the ankle joint and the hindfoot both changed to a varus trend after correction of varus deformity of the knee. Such changes in ankle joint and hindfoot alignment are considered to be due to the compensatory changes following alterations in lower limb alignment. Therefore, it is necessary to perform a meticulous examination of the ankle joint as well as the knee joint and consider subsequent alteration of ankle joint and hindfoot alignment before surgical correction of knee joint alignment.

Location of Activation of Tarsal Joints on SPECT CT Scan Predicts Preoperative Functional and Pain Scores on Supramalleolar Osteotomy Patients

Category: Ankle, Ankle Arthritis Introduction/Purpose: Combined single-photon emission computed tomography and conventional computed tomography (SPECT/CT) is a hybrid imaging modality that shows a combination of metabolic and structural information about the ankle. Recently, its use has expanded for pre-operative evaluation of supramalleolar osteotomies (SMO) for asymmetric ankle arthritis. It is unclear if the location of bone scan activation in other locations in the hindfoot is related to pre and post-operative functional and scores. We hypothesize that uptake in specific locations within the hindfoot can be associated with worse pre- and post- operative functional and pain scores. Methods: 85 pre-operative SMO patients with varus (37), valgus (41), or neutral (7) alignment of the hindfoot were assessed using SPECT/CT. The level of activation on SPECT/CT scans was measured. Activation was assessed on both the tibia and talus including the talonavicular, subtalar, calcaneocuboid joints and subfibular region. Pre- and post-operative functional and pain scores (AOFAS Hindfoot, FAOS, and VAS) were recorded for each patient at an average of 3.7 years post-operatively. We compared SPECT/CT imaging with pre-operative patient scores assuming equal group variance and used a Chi-square analysis to determine if failure can be related to having activation in other joints besides the hindfoot. Results: Those with talonavicular (6) activation had worse malalignment as measured by the AOFAS Hindfoot-A (alignment) subscore; they had worse a functional status as measured by the AOFAS-F (function) subscore. Patients with subtalar joint activation (10) had significantly worse (p&lt;.05) pre-operative VAS pain scores. They also had worse AOFAS-F, AOFAS Hindfoot, and FAOS-S (symptom) scores. Those with calcaneocuboid activation (1) did not have any correlation to pre-operative pain or functional scores. Patients with subfibular impingement (7) had worse alignment based on the AOFAS-A scores. Patients with hindfoot joint activation did not have a higher rate of failure relative to other locations in the ankle. Activation in these areas were not associated with any post-operative functional or pain scores. Conclusion: Pre-operative SPECT/CT evaluation of the hindfoot before a SMO can be used to clinically correlate patient-specific factors such as pain and function in the pre-operative period. Results from this study provide prognostic information the locations of lesions that may cause patients more functional disability and pain pre-operatively and in the future.

The Effect of Ankle Arthrodesis on the Biomechanical Function of the Foot

Category: Ankle, Ankle Arthritis, Basic Sciences/Biologics, Hindfoot Introduction/Purpose: Several studies on the effect on gait of total ankle arthroplasty (TAA) have demonstrated significant functional improvement post-operatively, compared to the patients’ preoperative function. While there are many post-operative studies showing abnormalities of gait in patients who have had ankle arthrodesis, there are very limited published data in ankle fusion which compare post-operative gait to the patients’ own preoperative function. Moreover, there are no published correlation of those gait changes with patient reported outcomes. Methods: Twenty-six consecutive ankle arthrodesis patients were prospectively studied, with pre- and post-operative three- dimensional gait analysis. Kinematic data were collected at 100 Hz with a twelve-camera digital Vicon motion capture system, and two OR6-5 AMTI force plates. Patients walked barefoot at a self-selected speed over a 10-meter walkway. A minimum 20 gait cycles were used for averaging and statistical analysis for temporal-spatial and kinematic parameters and a minimum of five force plate readings for kinetic parameters. Gait parameters were collected for both operated and unaffected limbs (i.e. control). Demographic data were compiled. Prospectively collected patient-reported outcomes included SF-36, VAS, AOFAS scores, which were repeated annually postoperatively. Results: Mean age was 56 (19 – 80) years, BMI 29.7 (18.6 - 45.6), and follow-up 21.9 (12 - 69) months. There were multiple objective parameters of gait which showed statistically significant functional improvements compared to preoperative performance. Temporal-spatial: Improvements were detected in walking speed, step length and cadence; single and double limb support time. Kinematic parameters: Increase in maximum plantarflexion, decrease in maximum dorsiflexion, but total sagittal range of motion was not diminished, and slightly increased (mean 1.8 degrees). The preservation of total sagittal motion after arthrodesis suggested either precise postoperative compensation by the hindfoot, or that most of the preoperative motion was already occurring in the surrounding hindfoot joints. Kinetic parameters: Improvement in ankle moment and hip power were detected. Patient reported outcomes (table) Conclusion: Ankle arthrodesis improves gait in end-stage arthritis, as demonstrated by statistically significant improvements in multiple, objective parameters. Moreover, the increase in sagittal plane motion of the hindfoot, presumed in the literature to be compensatory to the arthrodesis, was shown to be present pre-operatively, as well, suggesting it is also an effect of tibiotalar stiffness due to end-stage arthritis. Improvements in gait corresponded to clinical improvements as well, as demonstrated by improvements in patient reported outcomes in this population. Biomechanical improvements corresponded to clinical outcomes.

Role of Surgery in Management of Osteo-Articular Tuberculosis of the Foot and Ankle.

Background:Tuberculosis of the foot and ankle still remains to be a significant problem, especially in the developing countries, and with an increase in incidence in immunosuppressed patients. Treatment is mainly medical using multidrug chemotherapy; surgical interventions range from biopsy, synovectomy and debridement, to joint preserving procedures like distraction in early cases, and arthrodesis of hindfoot joints and the ankle in advanced disease with joint destruction.Surgical Options: All procedures should be done after initiating appropriate medical management. The ankle is the commonest joint needing intervention, followed by the subtalar and talo-navicular joint. Forefoot TB limited to the bone rarely needs surgical intervention except when the infective focus is threatening to invade a joint. Articular disease can spread rapidly, so early diagnosis and treatment can influence the outcome. Surgical interventions may need to be modified in the presence of sinuses and active disease; fusions need compression, and implants have to be chosen wisely. External fixators are the commonest devices used for compression in active disease, but intramedullary nails better stabilize pantalar arthrodesis. Arthroscopy has become a valuable tool for visualizing the ankle and hindfoot joints, and is an excellent adjunct for arthrodesis by minimally invasive methods.Conclusion:Although Osteoarticular Tb involving the foot and ankle is largely managed with chemotherapy, specific indications for surgical intervention exist. Timely done procedures could limit joint destruction, or prevent spread to adjacent joints. Fusions are the commonest procedure for sequelae of disease or for correcting residual deformity.

Correction of adult posttraumatic rigid severe pes equinovarus with tibiotalocalcaneal retrograde nailing

Introduction: Neglected pes equinovarus deformity at the adulthood is difficult to correct. It is usually a rigid deformity associated with arthritic changes of the hindfoot joint. Combined bone and soft tissue procedure is necessary to correct the deformity. Case report: We present a case of acquired severe rigid pes equinovarus in adulthood with varus ankle of 40

Arthroscopic subtalar arthrodesis through the sinus tarsi portal approach: A series of 77 cases

BackgroundSubtalar arthrodesis through an open approach carries significant risk of complications. An arthroscopic approach aims to minimise damage to the soft tissue envelope to improve recovery, union and complication rates. A two portal approach through the sinus tarsi was used. MethodsA retrospective review of all patients undergoing isolated arthroscopic arthrodesis was performed. ResultsSeventy-seven procedures were performed. Successful arthrodesis was achieved in 75 (97.4%). Two patients underwent successful revision arthrodesis for aseptic nonunion. There was one (1.3%) superficial infection and one (1.3%) partial sural nerve injury. ConclusionsTwo-portal sinus tarsi arthroscopic subtalar arthrodesis is safe and effective. Advantages over other arthroscopic approaches are the access to all three facets of the joint, avoidance of a posterolateral portal in order to minimise risk to the sural nerve, and the ability to use the same approach to arthrodese the entire triple hindfoot joint complex. Technical tips and pitfalls are discussed.

The reliability of the Adelaide in-shoe foot model

Understanding the biomechanics of the foot is essential for many areas of research and clinical practice such as orthotic interventions and footwear development. Despite the widespread attention paid to the biomechanics of the foot during gait, what largely remains unknown is how the foot moves inside the shoe. This study investigated the reliability of the Adelaide In-Shoe Foot Model, which was designed to quantify in-shoe foot kinematics and kinetics during walking. Intra-rater reliability was assessed in 30 participants over five walking trials whilst wearing shoes during two data collection sessions, separated by one week. Sufficient reliability for use was interpreted as a coefficient of multiple correlation and intra-class correlation coefficient of >0.61. Inter-rater reliability was investigated separately in a second sample of 10 adults by two researchers with experience in applying markers for the purpose of motion analysis. The results indicated good consistency in waveform estimation for most kinematic and kinetic data, as well as good inter-and intra-rater reliability. The exception is the peak medial ground reaction force, the minimum abduction angle and the peak abduction/adduction external hindfoot joint moments which resulted in less than acceptable repeatability. Based on our results, the Adelaide in-shoe foot model can be used with confidence for 24 commonly measured biomechanical variables during shod walking.

Biplane fluoroscopy for hindfoot motion analysis during gait: A model-based evaluation

The purpose of this study was to quantify the accuracy and precision of a biplane fluoroscopy system for model-based tracking of in vivo hindfoot motion during over-ground gait. Gait was simulated by manually manipulating a cadaver foot specimen through a biplane fluoroscopy system attached to a walkway. Three 1.6-mm diameter steel beads were implanted into the specimen to provide marker-based tracking measurements for comparison to model-based tracking. A CT scan was acquired to define a gold standard of implanted bead positions and to create 3D models for model-based tracking. Static and dynamic trials manipulating the specimen through the capture volume were performed. Marker-based tracking error was calculated relative to the gold standard implanted bead positions. The bias, precision, and root-mean-squared (RMS) error of model-based tracking was calculated relative to the marker-based measurements. The overall RMS error of the model-based tracking method averaged 0.43 ± 0.22mm and 0.66 ± 0.43° for static and 0.59 ± 0.10mm and 0.71 ± 0.12° for dynamic trials. The model-based tracking approach represents a non-invasive technique for accurately measuring dynamic hindfoot joint motion during in vivo, weight bearing conditions. The model-based tracking method is recommended for application on the basis of the study results.