Objectives. The objective of this study was to quantify the relative movement between the articular surfaces in the tibiotalar and subtalar joints during normal walking in asymptomatic individuals. Methods. 3D movement data of the ankle joint complex were acquired from 18 subjects using a biplanar fluoroscopic system and 3D-to-2D registration of bone models obtained from CT images. Surface relative velocity vectors (SRVVs) of the articular surfaces of the tibiotalar and subtalar joints were calculated. The relative movement of the articulating surfaces was quantified as the mean relative speed (RS) and synchronization index (SI. ENT. ) of the SRVVs. Results. SI. ENT. and mean RS data showed that the tibiotalar joint exhibited translational movement throughout the stance, with a mean SI. ENT. of 0.54 (. sd. 0.21). The mean RS of the tibiotalar joint during the 0% to 20% post heel-strike phase was 36.0 mm/s (. sd. 14.2), which was higher than for the rest of the stance period. The subtalar joint had a mean SI. ENT. value of 0.43 (. sd. 0.21) during the stance phase and exhibited a greater degree of rotational movement than the tibiotalar joint. The mean relative speeds of the subtalar joint in early (0% to 10%) and late (80% to 90%) stance were 23.9 mm/s (. sd. 11.3) and 25.1 mm/s (. sd 9.5). , respectively, which were significantly higher than the mean RS during mid-stance (10% to 80%). Conclusion. The tibiotalar and subtalar joints exhibited significant translational and rotational movement in the initial stance, whereas only the subtalar joint exhibited significant rotational movement during the late stance. The relative movement on the articular surfaces provided deeper insight into the interactions between articular surfaces, which are unobtainable using the joint coordinate system. Cite this article: C-B. Phan, D-P. Nguyen, K. M. Lee, S. Koo. Relative movement on the articular surfaces of the tibiotalar and subtalar joints during walking. Bone Joint Res 2018;7:501–507. DOI: 10.1302/2046-3758.78.BJR-2018-0014.R1

Purpose. The goal of Total Ankle Arthroplasty (TAA) is to relieve pain and restore healthy function of the intact ankle. Restoring intact ankle kinematics is an important step in restoring normal function to the joint. Previous robotic laxity testing and functional activity simulation showed the intact and implanted motion of the tibia relative to the calcaneus is similar. However there is limited data on the tibiotalar joint in either the intact or implanted state. This current study compares modern anatomically designed TAA to intact tibiotalar motion. Method. A robotic testing system including a 6 DOF load cell (AMTI, Waltham, MA) was used to evaluate a simulated functional activity before and after implantation of a modern anatomically designed TAA (Figure 1). An experienced foot and ankle surgeon performed TAA on five fresh-frozen cadaveric specimens. The specimen tibia and fibula were potted and affixed to the robot arm (KUKA Robotics Inc., Augsburg, Germany) while the calcaneus was secured to a fixed pedestal (Figure 1). Passive reflective motion capture arrays were fixed to the tibia and talus and a portable coordinate measuring machine (Hexagon Metrology Group, Stockholm, Sweden) established the location of the markers relative to anatomical landmarks palpated on the tibia. A four camera motion capture system (The Motion Monitor, Innovative Sports Training, Chicago, IL) recorded the movement of the tibia and talus. The tibia was rotated from 30 degrees plantar flexion to 15 degrees dorsiflexion to simulate motions during the stance phase of gait. At each flexion angle the robot found the orientation which zeroed all forces and torques except compressive force, which was either 44N or 200N. Results. Preliminary data indicates the tibiotalar motion of the TAA is similar to the intact ankle. The pattern and magnitude of tibiotalar translations and rotations are similar between the intact and implanted states for both 44N and 200N compressive loads (Figure 2). The most variation occurs with internal-external rotation. Increased translation especially in the anterior-posterior directions was observed in plantarflexion while the mediolateral translation remained relatively centered moving less than a millimeter. The intact talus with respect to the calcaneus had less than 3 degrees of rotation over the whole arc of ankle flexion (Figure 3). The angular motion of the implanted talus was similar in pattern to the intact talus, however there were offsets in all three angular directions which changed depending on the loading (Figure 3). This indicates that most of the motion that occurs between the intact tibial calcaneal complex occurs in the tibiotalar joint. Conclusion. Although more investigation is required, this study adds to the limited available tibiotalar kinematic data. This current study suggests the anatomical TAA design allows the tibiotalar joint to behave in similar way to the intact tibiotalar joint. Restoring intact kinematics is an important step in restoring normal function to the joint. For figures/tables, please contact authors directly.

Purpose: Indications for tibiotalar arthrodesis persist in patients with septic or inflammatory joint disease. Arthroscopic arthrodesis can be used to limit immediate postoperative morbidity. This technique has been used in our unit since 1994. The purpose of this work was to assess long-term outcome and specific complications. Material and methods: All patients who underwent arthroscopic tibiotalar arthrodesis since 1994 (16 patients) were reviewed by an independent observer. There were nine women and seven men, mean age 56 years (37–81). The cause of the tibiotalar disease was post-traumatic degeneration in 12 cases, primary osteoarthritis in two and rheumatoid polyarthritis in two. The ankle was centred preoperatively in all cases. Osteosynthesis was achieved with screw fixation in 14 cases and with an external fixator in two. Mean follow-up was 43.4 months (6–80 months). Outcome was assessed on the basis of delay to fusion, presence of residual pain, and complications induced by the technique. Results: Mean hospital stay was five days (3–11 days). There was no infectious or cutaneous complication. Three patients had a sensorial deficit in the territory of the superficial fibular nerve. Fusion was obtained in all patients. Mean delay to fusion was 3.4 months (range 2–7.5 months). All patients except one who had a painful fibulotalar non-union could walk without pain after fusion had been achieved. Discussion: Arthroscopic tibiotalar arthrodesisis a reliable procedure for the treatment of destroyed joints after centring the ankle. We were satisfied with the results of percutaneous screw fixation. Delay to fusion was comparable with delays observed after open procedures and complication rate was lower. Conclusion: Since the postoperative morbidity is low and long-term results are equivalent, we propose arthroscopic arthrodesis for the treatment of tibiotalar destruction

Purpose: Tibiotalar arthrodesis is a classical procedure for the treatment of painful deformation-destruction of the tibiotalar joint. The purpose of this retrospective study was to determine prognostic factors and tolerance to tibiotalar arthrodesis observed in 68 procedures performed with two different techniques (47 surgical fusions (Group 1), and 21 arthroscopic fusions (Group 2)). Material and methods: Between 1985 and 1999, 68 patients, mean age 51 years (22–88) underwent 55 arthrodesis procedures (47 post-traumatic, 2 paralytic, 6 rheumatoid polyarthritis, 4 sequelae of septic arthritis). All patients had major functional impairment. The tibiotalar joint was stiff in all cases and mean motion was 20 ± 15°. The subtalar facet was nearly normal in 33 cases, altered in six and had already fused in nine. The mediotarsal facet was altered in 12 cases, six had already had a double arthrodesis, and was normal in 50. On the preoperative Méary view, there was a normal axis in 13 patients, valgus in 28 and varus in 24. According to the Duquennoy radiographic criteria, there was subtalar involvement in 32 cases and mediotarsal involvement in 19. Tibiotalar arthrodeses procedures were performed arthroscopically after 1993 for cases with little axial deformation. Open surgery was used for all other cases (43 Méary technique). A plaster cast was used in all cases. All patients were reviewed using the Duguennoy score and two radiographic views: lateral weight-bearing view for the sagittal plane position (tibiopedious angle) and the Méary view for the frontal plane. Results: At a mean follow-up of four years, fusion rate was 82% (group 1 83%, group 2 81%). Mean delay to fusion was 3.2 ± 1 month irrespective of the causal disease or surgical technique. Functional outcome was very good in 28%, good in 34.5%, fair in 34.5% and poor in 3% and did not depend on the surgical technique. The subtalar was painful with zero motion in 18 cases (26.5%), generally associated with residual equine. The mediotarsal was stiff in 17 cases and very painful in four. In the frontal plane, 16 ankles were correctly axed, 27 were in valgus (mean 5.6°) and 20 in varus (mean 7.6°) with no difference between the two groups. In the sagittal plane, four ankles were in talus, nine in neutral position, and 49 had a residual equine, including 32 > 5°. In most cases, fair or poor outcome was related to subtalar pain. More than 50% of the patients with equine fusion greater than 5° had subtalar pain. Conclusion: For the same deformity, arthroscopic arthrodesis can shorten hospital stay and improve the rate and degree of trophic disorders. Arthroscopic tibiotalar arthrodesis is an elegant technique that we use for centred ankles or for patients with risk factors, particularly skin conditions. The rate of fusion with the arthroscopic approach is not however better than with open surgery. Precise clinical and radiological assessment of the subtalar facet as well as the position of the fusion in the sagittal plane at 90° without equine deviation are important prognostic factors observed in this series

Purpose: Fracture-dislocation of the talus is one of the most severe injuries of the ankle. Opinion varies widely as to the proper treatment of this injury. Since Blair’s original description of the tibiotalar fusion in 1943, there is little mention in the literature of his method. The present study reports tibiotalar arthrodesis with modification in Blair’s technique. Method: Eleven cases of modified Blair’s tibiotalar arthrodesis were retrospectively studied. The average age was 32.4 years (range, 26 to 51 years). Six patients had avascular necrosis; five had neglected fracture-dislocation of the talus. Results: All the 11 ankles united. Nine cases having 150–200 tibiopedal motion had excellent results and two ankles having 100–150 of tibiopedal motion had good result. The follow up ranged from 3 to 12 years. Conclusion: The principal modification in the present study is retention of the talar body while performing arthrodesis with anterior sliding graft. The retention of the talar body provides intraoperative stability and in long term, the retained talar body share the load transmitted to anterior and middle subtalar joints thus resulting into improved hind foot function and gait

From 1975 to 1990 we performed subtalar or triple arthrodesis on 54 patients; 48 of them were reviewed after a mean follow-up of 10 years (6 to 15). There were 17 subtalar fusions in 14 patients and 37 triple arthrodeses in 28 patients. We assessed tibiotalar ankle function using the criteria of Mazur which gives a points score of a maximum of 100. Radiological evidence of degenerative change was graded on a scale of 0 to 4. The mean Mazur score was 85 for the subtalar fusions and 78 for the triple arthrodeses. The radiological score showed no degenerative changes in 36 feet (24 triple and 12 subtalar arthrodeses) and an increase of one grade in 14 feet (10 triple and 4 subtalar), of two grades in three feet (all triple arthrodeses) and of three grades in one foot after a subtalar arthrodesis. We found no statistically significant difference in the radiological score in unilateral fusions between feet with subtalar and triple arthrodeses and the contralateral foot. In all four feet which showed an increase in degenerative changes of two or more grades, there was an abnormality of the tibiotalar joint before the fusion operation. Of the 14 feet which showed an increase of one grade, there was a similar increase on the contralateral side in nine. Our findings show that subtalar or triple arthrodesis has little adverse influence on the function of the tibiotalar joint, even after many years

Aims. Preoperative talar valgus deformity ≥ 15° is considered a contraindication for total ankle arthroplasty (TAA). We compared operative procedures and clinical outcomes of TAA in patients with talar valgus deformity ≥ 15° and < 15°. Methods. A matched cohort of patients similar for demographics and components used but differing in preoperative coronal-plane tibiotalar valgus deformity ≥ 15° (valgus, n = 50; 52% male, mean age 65.8 years (SD 10.3), mean body mass index (BMI) 29.4 (SD 5.2)) or < 15° (control, n = 50; 58% male, mean age 65.6 years (SD 9.8), mean BMI 28.7 (SD 4.2)), underwent TAA by one surgeon. Preoperative and postoperative radiographs, Ankle Osteoarthritis Scale (AOS) pain and disability and 36-item Short Form Health Survey (SF-36) version 2 scores were collected prospectively. Ancillary procedures, secondary procedures, and complications were recorded. Results. At mean 5.1 years follow-up (SD 2.6) (valgus) and 6.6 years (SD 3.3) (controls), mean AOS scores decreased and SF-36 scores increased significantly in both groups. Improvements in scores were similar for both groups – AOS pain: valgus, mean 26.2 points (SD 24.2), controls, mean 22.3 points (SD 26.4); AOS disability: valgus, mean 41.2 points (SD 25.6); controls, mean 34.6 points (SD 24.3); and SF-36 PCS: valgus, mean 9.1 points (SD 14.1), controls, mean 7.4 points (SD 9.8). Valgus ankles underwent more ancillary procedures during TAA (40 (80%) vs 13 (26%)) and more secondary procedures postoperatively (18 (36%) vs 7 (14%)) than controls. Tibiotalar deformity improved significantly (p < 0.001) towards a normal weightbearing axis in valgus ankles. Three valgus and four control ankles required subsequent fusion, including two for deep infections (one in each group). Conclusion. Satisfactory mid-term results were achieved in patients with preoperative valgus malalignment ≥ 15°, but they required more adjunctive procedures during and after TAA. Valgus coronal-plane deformity ≥ 15° is not an absolute contraindication for TAA if associated deformities are addressed. Cite this article: Bone Joint J 2020;102-B(12):1689–1696

The standard treatment of arthrosis of the ankle joint is arthrodesis while new prosthesis leed to good clinical results. Currently there is much controversial discussion, and knowledge of the fundamentals of biomechanics is becoming ever more important. Ten macroscopically and roentgenographically normal foot specimens were tested comparing tibio-talar arthodesis vs. nativ situation on a kinematic gait simulator. The stance- phase of normal walking gait was simulated from heel-contact to toe-off. Ground reaction forces were simulated by a tilting angle- and force-controlled translation stage upon which a pressure measuring platform was mounted. Force was applied to the tendons of the foot flexor and extensor muscle groups by cables attached to an additional set of six force-controlled hydraulic cylinders. Tibial rotation was produced by an electrical servo motor. The change after arthrodesis was a varying degree of relocation of average force and maximum pressure from the lateral onto the medial column of the foot; the increase force on talonavicular joint and decrease on calcaneocuboid joint is statistically significant. The average force increased from native 66.7N to 80.8N upon arthrodesis in the talonavicular joint and decreased in the calcaneocuboid joint from 71.9N to 58.5N. Peak pressure increased from 3728kPa to 4552kPa in talonavicular joint and decreased in calcaneocuboid joint from 3809kPa to 3627kPa. After arthrodesis, we measured inconsistent changes in Chopart joint. On some feet, the changes in stress were slight, but on majority, relocation of force and peak pressure was significant. The result was a change in the function of Chopart joint with increased extension load on talonavicular joint at time of highest joint load during push-off. These in vitro observations explain the clinical observations that have followed ankle arthrodesis. For one, there are reports on tibiotalar arthrodesis patients who are largely mobile and free of complaints, which correlates with the observation that not all preparations indicate a clear relocation of force and intraarticular peak pressure onto the talonavicular joint. In these cases, the ability of strong muscular plantar flexion could explain a good functional result. In contrast, and in addition to subtalar joint degeneration, arthroses in the talonavicular joint have been frequently observed following tibiotalar arthrodeses. The relocation of both force and intraarticular peak pressure onto the medial column of the foot in the majority of preparations explain the degeneration on the extensor side of the joint with osteophyte formation impressively

Purpose: The purpose of this study was to analyse changes in foot dynamics secondary to tibiotalar arthrodesis and examine the adaptation mechanisms induced by wearing shoes. Material and methods: A 3D gait analysis was performed (Vicon 370) in ten patients with a tibiotalar arthrodesis fixed in a neutral position and in ten matched controls. Recordings were made in three conditions: walking barefooted, walking at a comfortable self-chosen speed wearing shoes, and walking at maximal speed wearing shoes. We measured tibial inclination in the sagittal plane, knee flexion, and the tibia-forefoot angle produced at heel lift-off. The distance of the ground reaction force (GRF) from the heel was measured during the weight-bearing phase and at lift-off. Statistical comparisons were made with the contralateral side and the control group. Results: Heel lift-off came significantly earlier on the arthrodesis side compared with the contralateral side and with the control group. At heel lift-off, the knee was in complete extension in all three groups. The GRF moved forward more rapidly but remained more posterior on the arthodesis side at heel lift-off in comparison with the contralateral side and the control group. Wearing shoes enabled later heel lift-off on the arthrodesis side and increased tibial inclination at lift-off as well as decreased speed of the anterior displacement of the GRF. The GRF however remained more posterior than in the control group. At maximal walking speed, heelk lift-off came earlier on the arthrodesis side and at the same time a lesser anterior tibial inclination and a more posterior position of the GRF. Discussion: Early heel lift-off on the arthrodesis side allows anterior inclination of the tibia to continue and to increase stride length. Heel lift-off however occurs when the GRF has not yet advanced to the metatarsophalangeal position, thus increasing stress on the rear and mid foot. Wearing shoes improves the kinematic parameters and decreases stress on the joints below the arthrodesis. Increased walking speed aggravates the perturbed foot dynamics when walking

Ankle arthrodesis is the gold standard for treatment of end stage ankle arthritis. We analysed the data of 124 Ankle Arthrodesis (Open Ankle Arthrodesis (OAA) −27; Arthroscopic Ankle Arthrodesis (AAA)- 97) performed between January 2005 and December 2015 by fellowship trained foot and ankle surgeons in a single institution. Based on preoperative deformity (AAA- 28 degree valgus to 26 degrees varus; OAA- 41 degree valgus to 28 degree varus), they were subdivided into 2 groups based upon deformity more than 15 degrees. Union rates, time to union, length of hospital stay and patient related factors like smoking, alcoholism, diabetes, BMI were assessed. Mean age of patients was 60 years (Range 20 to 82 years)(Male:Female-87:32). Overall fusion rate was 93% in AAA and 89% in OAA (p=0.4). On sub group analysis of influence of preoperative deformity, there was no difference in union rates of AAA versus OAA. 7 patients in AAA and 3 in OAA required further procedures. Average time to union was 13.7 in AAA and 12.5 weeks in OAA (p=0.3). Average hospital stay was 2.6 days in AAA and 3.8 days in OAA (p=0.003). Smoking, alcoholism, Diabetes, BMI did not have any correlation with union rates. Although both AAA and OAA showed good union rates, hospital stay was significantly shorter in AAA. A larger deformity did not adversely affect union rates in AAA. Time to union was higher in AAA though it was statistically insignificant. Lifestyle risk factors did not have cumulative effect on union. We conclude that AAA is a reproducible method of treating end stage tibiotalar arthritis irrespective of preoperative deformity and patient related factors

Purpose: We evaluated the role of the Distal Tibial Line (DTL by Saltzman et al, 2005) in measuring the pre-operative and postoperative position of the talus on ‘lateral’ radiographs following a Total Ankle Replacement (TAR). Currently there is no validated measure of anteroposterior (AP) alignment of a TAR. Arthritis in the ankle causes considerable malalignment in the anteroposterior plane. The DTL is not affected by the destruction of the tibiotalar joint and is independent of slight variations in the positioning of the foot and radiological magnification. Method: DTL divides the talus into two sections and the proportionate length of the posterior segment is presented as a ratio. The size of the posterior segment and ratio decreases with anterior subluxation. Radiographs of 200 cases of TAR were reviewed. The anterior and posterior outlines of the talus could not be seen in all cases (e.g. preoperative talonavicular fusion). As a result 49 cases of inflammatory arthritis (49 of 119) and 6 of osteoarthritis (6 of 81) could not be assessed. Results: The osteoarthritic ankle (OA) in particular showed a tendency for anterior subluxation. The average ratio in OA cases increased from ‘34.8′ before surgery to ‘40.4’ after surgery, confirming a trend for this subluxation to reduce with a TAR. There was a lesser tendency for subluxation in the inflammatory group of patients although the body of the talus itself was more deformed. The average preoperative value was ‘36.1’ and the post operative value was ‘38.9’. Conclusion: We found the Distal Tibial line to be a reproducible parameter for measurement of AP alignment in TAR in the vast majority of OA cases. The change of anteroposterior alignment post surgery appears to be due to the restoration of soft tissue balance

Background: Complex tibiotalar (TT) and tibiotalocalcaneal (TTC) fusions are performed for significant ankle and hindfoot arthritis and/or deformity. Literature suggests several methods of fixation including crossed screws, plates, nail and external fixation. These are technically difficult operations with reported complication rates as high as 30–80%. We present a retrospective cohort study of angle blade plate and PHILOS plate fixation for these patients in our hospital. Methods: This study describes 21 consecutive patients with 22 TT or TTC fusions between December 2005 and May 2009. The surgery was performed for severe deformity or arthritis as a result of: osteoarthritis(2), post-traumatic arthritis(4), rheumatoid arthritis (7), Charcot arthropathy (5), avascular necrosis(1), and post traumatic avascular necrosis (3). The senior author performed all of the operations. In the first ten cases (two TT and eight TTC) an angle blade plate was used, A PHILOS plate was used in the subsequent ten cases (three TT and seven TTC). One patient had bilateral TTC fusions with a blade plate on one side and a PHILOS plate on the other. There were eight male and 13 female patients. All the procedures were performed through a lateral transfibular approach. The patients were followed up regularly with clinical and radiological evaluation until union or otherwise. Results: Fusion was achieved in 19 out of 21 patients (90.5%) and 20 out of 22 arthrodeses (90.9%). All five TT fusions went on to union (100%). Fifteen out of 17 TTC fusions united (88.2%). One TTC fusion using an angle blade plate needed revision surgery for non-union of subtalar joint. In the PHILOS group one patient developed MRSA infection of the surgical site leading to non-union. This necessiated removal of metal and prolonged treatment with intravenous antibiotics. The patient now has a relatively painless fibrous ankylosis. Conclusion: TT and TTC fusions are complex operations performed for severe arthritis and deformity, often on patients with significant co-morbidities. It is a salvage procedure to relieve pain and/or correct deformity of the foot and ankle. This study suggests that both the angle blade plate and PHILOS plate provide a stable fixed angle construct, which achieves a high rate of bony union with alignment correction

Aim

Post traumatic distal tibia osteomyelitis (DTOM) with an upper ankle joint involvement is a serious complication after primary osteosynthesis and can be a nightmare for the patient and the surgeon as well. Our aim was to identify mayor complications during treatment and to find the way to prevent or treat them.

Introduction: Arthrodesis has been recommended for the treatment of end-stage osteoarthritis of the ankle joint, especially as the results of prosthetic ankle replacement are not comparable with those achieved with total hip or knee replacement. In vitro studies revealed that ankle arthrodesis restricts kinematics more than total ankle replacement in terms of range of motion as well as movment transfer. However, little is known about in vivo gait patterns in patients with arthrodesis of the ankle joint.

Aim of this retropective study was to determine plantar pressure distribution in patients who underwent ankle arthrodesis with a standardized screw fixation technique in a single surgeon population.

Methods: 21 patients (7 male/14 female) who underwent isolated unilateral ankle arthrodesis with 3 crossed 7,3 mm AO screws (Synthes Gmbh, Austria) in a standardized technique by a single surgeon between October 2000 and January 2008 have been included in this study. At a mean follow-up of 25 months (range 12 – 75) pedobarograhy (Novel GmbH., Munich), clinical evaluation using the AOFAS hindfoot score and weight-bearing x-rays of the foot were performed.

Results: Pedobarographic assessment revealed no statistically significant difference between the operated foot and the contralateral foot eighter in terms of peak pressure, maximum force, contact area and contact time or the gait line parameters velocity of center of pressure, lateral-medial force indices or lateral-medial area indices.

The average AOFAS score was 80,5 (range 46 – 92) and mean tibioplantar angle determined on the lateral standing radiograph was 91° (82° – 100°). Non-union didn’t occur in any patient.

Discussion: The results of the present study indicate that ankle arthrodesis restores plantar pressure distribution patterns to those of healthy feet. Therefore, the functional outcome of ankle arthrodesis seems to be good as long as the fusion is in fixed in an appropriate position.

Aims

Postoperative rehabilitation regimens following ankle arthrodesis vary considerably. A systematic review was conducted to determine the evidence for weightbearing recommendations following ankle arthrodesis, and to compare outcomes between different regimens.

To be able to assess the biomechanical and functional effects of ankle injury and disease it is necessary to characterise healthy ankle kinematics. Due to the anatomical complexity of the ankle, it is difficult to accurately measure the Tibiotalar and Subtalar joint angles using traditional marker-based motion capture techniques. Biplane Video X-ray (BVX) is an imaging technique that allows direct measurement of individual bones using high-speed, dynamic X-rays. The objective is to develop an in-vivo protocol for the hindfoot looking at the tibiotalar and subtalar joint during different activities of living. A bespoke raised walkway was manufactured to position the foot and ankle inside the field of view of the BVX system. Three healthy volunteers performed three gait and step-down trials while capturing Biplane Video X-Ray (125Hz, 1.25ms, 80kVp and 160 mA) and underwent MR imaging (Magnetom 3T Prisma, Siemens) which were manually segmented into 3D bone models (Simpleware Scan IP, Synopsis). Bone position and orientation for the Talus, Calcaneus and Tibia were calculated by manual matching of 3D Bone models to X-Rays (DSX Suite, C-Motion, Inc.). Kinematics were calculated using MATLAB (MathWorks, Inc. USA). Pilot results showed that for the subtalar joint there was greater range of motion (ROM) for Inversion and Dorsiflexion angles during stance phase of gait and reduced ROM for Internal Rotation compared with step down. For the tibiotalar joint, Gait had greater inversion and internal rotation ROM and reduced dorsiflexion ROM when compared with step down. The developed protocol successfully calculated the in-vivo kinematics of the tibiotalar and subtalar joints for different dynamic activities of daily living. These pilot results show the different kinematic profiles between two different activities of daily living. Future work will investigate translation kinematics of the two joints to fully characterise healthy kinematics

The April 2024 Foot & Ankle Roundup. 360. looks at: Safety of arthroscopy combined with radial extracorporeal shockwave therapy for osteochondritis of the talus; Bipolar allograft transplantation of the ankle; Identifying risk factors for osteonecrosis after talar fracture; Balancing act: immediate versus delayed weightbearing in ankle fracture recovery; Levelling the field: proximal supination osteotomy’s efficacy in severe and super-severe hallux valgus; Restoring balance: how adjusting the tibiotalar joint line influences movement after ankle surgery

Aims. The aim of this study was to report the results of three forms of reconstruction for patients with a ditsl tibial bone tumour: an intercalary resection and reconstruction, an osteoarticular reconstruction, and arthrodesis of the ankle. Methods. A total of 73 patients with a median age of 19 years (interquartile range (IQR) 14 to 36) were included in this retrospective, multicentre study. Results. Reconstructions included intercalary resection in 17 patients, osteoarticular reconstruction in 11, and ankle arthrodesis in 45. The median follow-up was 77 months (IQR 35 to 130). Local recurrence occurred in eight patients after a median of 14 months (IQR 9 to 36), without a correlation with adequacy of margins or reconstructive technique. Major complications included fracture of the graft in ten patients, nonunion of the proximal osteotomy in seven, and infection in five. In the osteoarticular group, three of 11 patients developed radiological evidence of severe osteoarthritis, but only one was symptomatic and required conversion to ankle arthrodesis. Functional evaluation showed higher values of the Musculoskeletal Tumour Society (MSTS) and American Orthopaedic Foot and Ankle Society (AOFAS) scores in the intercalary group compared with the others. Conclusion. Preservation of the epiphysis in patients with a distal tibial bone tumour is a safe and effective form of limb-sparing treatment. It requires rigorous preoperative planning after accurate analysis of the imaging. When joint-sparing resection is not indicated, ankle arthrodesis, either isolated tibiotalar or combined tibiotalar and subtalar arthrodesis, should be preferred over osteoarticular reconstruction. Cite this article: Bone Joint J 2020;102-B(11):1567–1573

Background. The 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. Methods. In 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. Results. The 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< 0.0001). As the tibiotalar angle became more valgus, the foot became more externally rotated relative to the TMA(pearson correlation −0.4;p< 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°). Conclusion. There 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

Background. Ankle and hindfoot fusion in the presence of large bony defects represents a challenging problem. Treatment options include acute shortening and fusion or void filling with metal cages or structural allograft, which both have historically low union rates. Impaction grafting is an alternative option. Methods. A 2 centre retrospective review of consecutive series of 32 patients undergoing hindfoot fusions with impaction bone grafting of morselised femoral head allograft to fill large bony void defects was performed. Union was assessed clinically and with either plain radiography or weightbearing CT scanning. Indications included failed total ankle replacement (24 patients), talar osteonecrosis (6 patients) and fracture non-union (2 patients). Mean depth of the defect was 29 ±10.7 mm and mean maximal cross-sectional area was 15.9 ±5.8 cm. 2. Tibiotalocalcaneal (TTC) arthrodesis was performed in 24 patients, ankle arthrodesis in 7 patients and triple arthrodesis in 1 patient. Results. Mean age was 57 years (19–76 years). Mean follow-up of 22.8 ±8.3 months. 22% were smokers. There were 4 tibiotalar non-unions (12.5%), two of which were symptomatic. 10 TTC arthrodesis patients united at the tibiotalar joint but not at the subtalar joint (31.3%), but only two of these were symptomatic. The combined symptomatic non-union rate was 12.5%. Mean time to union was 9.6 ±5.9 months. One subtalar non-union patient underwent re-operation at 78 months post-operatively after failure of metalwork. Two (13%) patients developed a stress fracture above the metalwork that healed with non-operative measures. There was no bone graft collapse with all patients maintaining bone length. Conclusion. Impaction of morselised femoral head allograft can be used to fill large bony voids around the ankle and hindfoot when undertaking arthrodesis, with rapid graft incorporation and no graft collapse despite early loading. This technique offers satisfactory union outcomes without the need for shortening or synthetic cages