scholarly journals Syndesmotic Instability After Total Ankle Replacement

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0010
Author(s):  
Roxa Ruiz ◽  
Lukas Zwicky ◽  
Beat Hintermann

Category: Ankle Arthritis Introduction/Purpose: Total ankle replacement (TAR) evolved over the last decades and has been shown to be an effective concept in the treatment of ankle osteoarthritis (OA). In three-component designs, the second interface between polyethylene insert (PI) and tibial component allows the PI to find its position according the individual physiological properties. This was believed to decrease shear forces within the ankle joint. However, it is not clarified to which extent such an additional degree of freedom may overload the ligamentous structures of the ankle joint over time. This may in particular be the case for the syndesmotic ligaments. Therefore, the purpose of this study was to analyze all ankles after TAR that showed a symptomatic overload of the syndesmotic ligaments and to determine the potential consequences. Methods: Between 2003 and 2017, 31 ankles (females, 17; males 14; mean age 60 [40-79] years) were treated with a tibio-fibular fusion for a symptomatic instability of the syndesmosis. The indication for TAR was posttraumatic OA in 27 (87%), primary OA in 3 (10%), and hemochromatosis in one ankle (3%). The 31 ankles included 23 primary TAR (74%), 6 revision TAR (19%), and two take-down of a fusion and conversion to TAR (7%). Criteria for fusion were the presence of at least two of the followings: (1) tenderness over the syndesmosis, (2) pain while compressing the fibula against the tibia (squeeze test), (3) pain while rotating the foot externally (external rotation test), (4) widening of the syndesmosis on an anteroposterior view. Alignment of TAR (tibial articular surface [TAS] angle) and hindfoot alignment were measured on standard radiographs. Intraoperatively, the syndesmotic instability was confirmed before fusion. The wear of PI was documented. Results: After a mean of 63 (range, 4 – 152) months after TAR, all patients evidenced pain at the level of the syndesmosis of at least 3 months. 25 ankles (81%; 24 after posttraumatic OA) showed a widening of the syndesmotic space and 22 ankles (71%) of the medial clear space with lateral translation of the talus. The PI was seen to overlap the tibial component in 15 ankles (48%). Nine ankles (29%) evidenced cyst formation, and eight ankles (26%) showed a decrease in height of the PI; whereas, in 3 ankles (10%) a fracture of the PI was found. A valgus misalignment of the heel was found in 25 ankles (81%), a valgus TAS in 16 (52%) and a varus TAS in 11 ankles (36%). Conclusion: A syndesmotic instability after a three-component TAR apparently occurred mostly after posttraumatic OA, in particular if the heel was left in valgus. If the talus starts to move lateralward, the PI seems to be at risk for increased wear and finally mechanical failure (Figure 1). Therefore, a valgus misaligned heel should always be corrected during TAR implantation. If there is any sign of syndesmotic instability, a fusion should be considered. Further studies must proof whether in cases with a syndesmotic instability the use of a two-component design will be superior, as it stabilizes the talus in the coronal plane.

2019 ◽  
Vol 40 (12) ◽  
pp. 1408-1415
Author(s):  
Thos Harnroongroj ◽  
Lauren G. Volpert ◽  
Scott J. Ellis ◽  
Carolyn M. Sofka ◽  
Jonathan T. Deland ◽  
...  

Background: Bone quality in the distal tibia and talus is an important factor contributing to initial component stability in total ankle replacement (TAR). However, the effect of ankle arthritis on bone density in the tibia and talus remains unclear. The objective of this study was to compare bone density of tibia and talus in arthritic and nonarthritic ankles as a function of distance from ankle joint. Methods: We retrospectively reviewed 93 end-stage ankle arthritis patients who had preoperative nonweightbearing ankle computed tomography (CT) and identified a cohort of 83 nonarthritic ankle patients as a demographic-matched control group. A region of interest tool was used to calculate Hounsfield unit (HU) values in the cancellous region of the tibia and talus. Measurements were obtained on axial cut CTs from 6 to 12 mm above the tibial plafond, and 1 to 4 mm below the talar dome. HU measurements between groups and the decrease of HU at the relative level in each group were compared. Results: Arthritic ankles demonstrated significantly greater mean bone density than nonarthritic ankles at between 6 and 10 mm above the joint in the tibia ( P < .05). No significant difference in bone density between 10 and 12 mm from the joint in the tibia nor at any level of the talus was found between groups. In both groups, bone density decreased significantly at each successive level away from the ankle joint. Conclusion: Ankle arthritis patients demonstrated greater or equal bone density in both the tibia and talus compared to demographic-matched controls. In both groups, bone density decreased with increasing distance away from the articular surface. In TAR, tibial bone resection between 6 and 8 mm may provide improved initial implant stability. Level of Evidence: Level III, comparative study.


2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0000
Author(s):  
Manja Deforth ◽  
Nicola Krähenbühl ◽  
Lukas Zwicky ◽  
Markus Knupp ◽  
Beat Hintermann

Category: Ankle Introduction/Purpose: A key for success in total ankle replacement is a balanced ankle joint. If the tibial component is misaligned, the ligamentous structures, the malleoli and the tendons may be overused, which, may lead to pain and impairment during gait. A misaligned tibial component can be revised using a corrective bone resection and re-insertion of a new component or using a corrective osteotomy of the distal tibia above the stable implant. The aim of this study was to review a series of patients, in whom a corrective supramalleolar osteotomy was performed to realign a misaligned tibial component in total ankle replacement. Methods: Twenty-two patients (nine male; 13 female; mean age, 62.6 years; range, 44.7 – 80.0) were treated with a supramalleolar osteotomy to correct a painful dysbalanced ankle, following a varus implanted tibial component. Following radiological and clinical outcomes were recorded preoperatively and at the follow-up examination within the first 24 months: the tibial anterior surface angle (TAS), the tibial lateral surface angle (TLS), patient’s pain measured with the Visual Analogue Scale (VAS), the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score, range of motion (ROM) of the ankle and patient’s satisfaction. Furthermore, postoperative complications were reviewed. Results: The TAS changed on average from 85.2 ± 2.5 degrees preoperatively to 91.4 ± 2.9 degrees postoperatively (p < 0.0001), the AOFAS score increased from 46 ± 14 to 66 ± 16 points (p < .0001) and the VAS pain score decreased from 5.8 ± 1.9 to 3.3 ± 2.4 (p < .001). No statistical difference was found in the TLS and the range of motion. The osteotomy healed in 19 patients (86%), re-osteosynthesis was successful in the remaining three patients. In one of these three patients, a chronic infection of the ankle joint led to a below-knee amputation. Fifteen patients (68%) were (very) satisfied, four (18%) moderately satisfied and three (14 %) patients were not satisfied with the obtained postoperative result. Conclusion: The supramalleolar osteotomy was found to be an efficient alternative to correct the misaligned tibial component in total ankle replacement. Pain could be successfully addressed in the majority of the patients. The treatment of a malpositioned, well anchored tibial component with a supramalleolar osteotomy, instead of exchanging the tibial component, allows preservation of the bone stock. However, non-union should be mentioned as a possible complication of this surgery. Nonetheless, this method might be a feasible treatment option, especially for younger patients.


2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0009
Author(s):  
James Nunley ◽  
Samuel Adams ◽  
James DeOrio ◽  
Mark Easley

Category: Ankle Arthritis Introduction/Purpose: Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported longterm for MB-TAR and at intermediate-to-longterm follow-up for newer generation FB-TAR. Although comparisons between the two total ankle designs have been reported, to our knowledge, no investigation has compared the two designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis. Methods: This investigation was approved by our institution’s IRB committee. Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65, range 35 to 85) were enrolled; demographic comparison between the two cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees or extensive talar dome wear pattern (“flat top talus”). Prospective patient-reported outcomes, physical exam and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score (VAS), short form 36 (SF-36), foot and ankle disability index (FADI), short musculoskeletal functional assessment (SMFA) and AOFAS ankle-hindfoot score. Surgeries were performed by non-design team orthopaedic foot and ankle specialists with total ankle replacement expertise. Statistically analysis was performed by a qualified statistician. Results: At average follow-up of 4.5 years (range 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, one had died, 4 were withdrawn after enrolling but prior to surgery and 4 were lost to follow-up. In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up. There was no statistically significant difference in improvement in clinical outcomes between the two groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FB-TAR, respectively. Re-operations were performed in 8 MB-TAR and 3 FB-TAR, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants. Conclusion: For the first time, with a high level of evidence, our study confirms that patient reported and clinical outcomes are favorable for both designs and that there is no significant difference in clinical improvement between the two implants. The incidence of lucency/cyst formation was similar for MB-TAR and FB-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not correlate with radiographic findings. Re-operations were more common for MB-TAR and in the majority of cases were to relieve impingement or treat cysts rather than revise or remove metal implants.


2019 ◽  
Vol 40 (11) ◽  
pp. 1239-1248 ◽  
Author(s):  
James A. Nunley ◽  
Samuel B. Adams ◽  
Mark E. Easley ◽  
James K. DeOrio

Background: Outcomes of total ankle replacement for the treatment of end-stage ankle arthritis continue to improve. Debate continues whether a mobile-bearing total ankle replacement (MB-TAR) or a fixed-bearing total ankle replacement (FB-TAR) is superior, with successful outcomes reported long term for MB-TAR and at intermediate- to long-term follow-up for newer generation FB-TAR. Although comparisons between the 2 total ankle designs have been reported, to our knowledge, no investigation has compared the 2 designs with a high level of evidence. This prospective, randomized controlled trial conducted at a single institution compares patient satisfaction, functional outcomes, and radiographic results of the mobile-bearing STAR and the fixed-bearing Salto-Talaris in the treatment of end-stage ankle arthritis. Methods: Between November 2011 and November 2014, adult patients with end-stage ankle osteoarthritis failing nonoperative treatment were introduced to the study. With informed consent, 100 patients (31 male and 69 female, average age 65 years, range 35-85 years) were enrolled; a demographic comparison between the 2 cohorts was similar. Exclusion criteria included inflammatory arthropathy, neuropathy, weight exceeding 250 pounds, radiographic coronal plane deformity greater than 15 degrees, or extensive talar dome wear pattern (“flat-top talus”). Prospective patient-reported outcomes, physical examination, and standardized weightbearing ankle radiographs were obtained preoperatively, at 6 and 12 months postoperatively, and then at yearly intervals. Data collection included visual analog pain score, Short Form 36, Foot and Ankle Disability Index, Short Musculoskeletal Functional Assessment, and American Orthopaedic Foot & Ankle Society ankle-hindfoot score. Surgeries were performed by a nondesign team of orthopedic foot and ankle specialists with total ankle replacement expertise. Statistical analysis was performed by a qualified statistician. At average follow-up of 4.5 years (range, 2-6 years) complete clinical data and radiographs were available for 84 patients; 7 had incomplete data, 1 had died, 4 were withdrawn after enrolling but prior to surgery, and 4 were lost to follow-up. Results: In all outcome measures, the entire cohort demonstrated statistically significant improvements from preoperative evaluation to most recent follow-up with no statistically significant difference between the 2 groups. Radiographically, tibial lucency/cyst formation was 26.8% and 20.9% for MB-TAR and FB-TAR, respectively. Tibial settling/subsidence occurred in 7.3% of MB-TAR. Talar lucency/cyst formation occurred in 24.3% and 2.0% of MB-TAR and FB-TAR, respectively. Talar subsidence was observed in 21.9% and 2.0% of MB-TAR and FH-TAR, respectively. Reoperations were performed in 8 MB-TARs and 3 FH-TARs, with the majority of procedures being to relieve impingement or treat cysts and not to revise or remove metal implants. Conclusion: With a high level of evidence, our study found that patient-reported and clinical outcomes were favorable for both designs and that there was no significant difference in clinical improvement between the 2 implants. The incidence of lucency/cyst formation was similar for MB-TAR and FH-TAR for the tibial component, but the MB-TAR had greater talar lucency/cyst formation and tibial and talar subsidence. As has been suggested in previous studies, clinical outcomes do not necessarily correlate with radiographic findings. Reoperations were more common for MB-TAR and, in most cases, were to relieve impingement or treat cysts rather than revise or remove metal implants. Level of Evidence: Level I, prospective randomized study.


2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0004
Author(s):  
Francois Lintz ◽  
Jef Mast ◽  
Nazim Mehdi ◽  
Alessio Bernasconi ◽  
Cesar de Cesar Netto ◽  
...  

Category: Ankle, Ankle Arthritis Introduction/Purpose: Peri-prosthetic cysts (PPC) in Total Ankle Replacement (TAR) are a common failure cause but the mechanisms of their development remains unclear. One possible explanation could be hindfoot malalignment and subsequent unequal distribution of load inside the joint. However, how residual malalignment influences the evolution of PPC remains unclear. Computed tomography (CT) has demonstrated superiority on conventional radiography in the follow up of PPC. Weight Bearing CT (WBCT), by combining 3D imaging and weight bearing measurements seems a valid tool to investigate this further. The objective for this work was to study the effects of residual hindfoot deformity on the distribution of PPC in the coronal plane. We hypothesized that cysts would be found predominantly medially in varus configuration, and laterally in valgus configuration. Methods: Retrospective comparative study, ethics committee approved. Forty-eight cases of TAR were included, with relevant demographics. Inclusion criteria were cases of primary TAR with available WBCT imaging of their ankle as part of normal follow up. Exclusion criteria were subsequent implant revision or cyst grafting. In each case, the localization and size of PPC’s were documented and their volume calculated by approximation of the closest ellipsoid. Hindfoot alignment was evaluated by the percentage Foot Ankle Offset (FAO) (foot-length normalized 3D ratio between the midline of the foot and the center of the ankle) using a WBCT dedicated semi-automatic software. The mean FAO value with 95%CI for the population was calculated. The difference in medial and lateral cyst volume defined by their position relative to the median axis in the coronal plane was compared in varus and valgus cases by a Mann-Whitney non-parametric test for unpaired samples. Results: Demographic distributions of the series were 32% female, mean age 65 (45-85) years. Mean FAO value was 0.12% (95%CI -1.09 to 1.33). Mean follow up was 43 months (6 to 239). The mean total cyst volume per case was 1190,7 mm3. In varus cases (defined by FAO<-1.09%), the volume of medial cysts was greater than laterally by a mean 197 mm3, whereas in valgus cases (defined by FAO>1.33%), the volume of lateral cysts was greater than medially by a mean 332 mm3. The difference was statistically significant (p<0.05). There was a weak, significant positive correlation (r=0.25, p<0,001) between FAO and total cyst volume and a moderate, significant correlation (r=0,56, p<0,001) between time to follow up and total cyst volume. Conclusion: Our hypothesis was confirmed. Periprosthetic cysts volume in this series of primary TAR was found to be relatively greater medially in postoperative varus configurations and vice-versa laterally in valgus. This confirms a possible correlation between the direction of residual hindfoot malalignment and the coronal localization of PPC in TAR, although this is certainly not the only pathophysiologic factor involved in PPC onset. Weightbearing CT may be helpful in Total Ankle Replacement follow up, in order to early detect PPC development and possibly to identify situations at risk of a more rapid evolution.


2017 ◽  
Vol 38 (9) ◽  
pp. 952-956 ◽  
Author(s):  
Manja Deforth ◽  
Nicola Krähenbühl ◽  
Lukas Zwicky ◽  
Markus Knupp ◽  
Beat Hintermann

Background: Persistent pain despite a total ankle replacement is not uncommon. A main source of pain may be an insufficiently balanced ankle. An alternative to the revision of the existing arthroplasty is the use of a corrective osteotomy of the distal tibia, above the stable implant. This strictly extraarticular procedure preserves the integrity of the replaced joint. The aim of this study was to review a series of patients in whom a corrective supramalleolar osteotomy was performed to realign a varus misaligned tibial component in total ankle replacement. We hypothesized that the supramalleolar osteotomy would correct the malpositioned tibial component, resulting in pain relief and improvement of function. Methods: Twenty-two patients (9 male, 13 female; mean age, 62.6 years; range, 44.7-80) were treated with a supramalleolar osteotomy to correct a painful ankle with a varus malpositioned tibial component. Prospectively recorded radiologic and clinical outcome data as well as complications and reoperations were analyzed. Results: The tibial anterior surface angle significantly changed from 85.2 ± 2.5 degrees preoperatively to 91.4 ± 2.9 degrees postoperatively ( P < .0001), the American Orthopaedic Foot & Ankle Society hindfoot score significantly increased from 46 ± 14 to 66 ± 16 points ( P < .0001) and the patient’s pain score measured with the visual analog scale significantly decreased from 5.8 ± 1.9 to 3.3 ± 2.4 ( P < .001). No statistical difference was found in the tibial lateral surface angle and the range of motion of the ankle when comparing the preoperative to the postoperative measurements. The osteotomy healed in all but 3 patients on first attempt. Fifteen patients (68%) were (very) satisfied, 4 moderately satisfied, and 3 patients were not satisfied with the result. Conclusion: The supramalleolar osteotomy was found to be a reliable treatment option for correcting the varus misaligned tibial component in a painful replaced ankle. However, nonunion (14%) should be mentioned as a possible complication of this surgery. Nonetheless, as a strictly extraarticular procedure, it did not compromise function of the previously replaced ankle, and it was shown to relieve pain without having to have revised a well-fixed ankle arthroplasty. Level of evidence: Level IV, case series.


2008 ◽  
Vol 1 (4) ◽  
pp. 276-294 ◽  
Author(s):  
Junitha M. Michael ◽  
Ashkahn Golshani ◽  
Shawn Gargac ◽  
Tarun Goswami

2010 ◽  
Vol 31 (10) ◽  
pp. 871-879 ◽  
Author(s):  
Arno Frigg ◽  
Benno Nigg ◽  
Laura Hinz ◽  
Victor Valderrabano ◽  
Iain Russell

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0002
Author(s):  
Camilla Maccario ◽  
Cristian Indino ◽  
Luigi Manzi ◽  
Federico Giuseppe Usuelli ◽  
Claudia Di Silvestri

Category: Ankle, Ankle Arthritis Introduction/Purpose: Primary ankle osteoarthritis is very uncomon, in fact 70-78% of the case ankle arthritis has a post- traumatic cause. Ankle arthrodesis (AA), has been considered a reliable procedure for resolution of ankle osteoarthritis. Recent modifications in Total ankle replacement (TAR) designs have challenged the perception that AA is the treatment of choice for end-stage ankle arthritis. Trabecular Metal Total Ankle system is a fixed-bearing prosthesis. The new design is flanked by use of new materials. The tibial articular surface is constructed of highly crosslinked UHMWPE and Trabecular Metal lining the talar and the tibial base component. The purpose of this retrospective study was to show the preliminary result in 31 patients underwent to ankle replacement using Zimmer Trabecular Metal Total Ankle system. Methods: We retrospectively assessed prospectively collected data on the initial cohort of 31 patients undergoing TAR with this implant. Clinical evaluation was determined pre and postoperatively for a minimum of 24 months after surgery. Pain was rated using the visual analogue scale (VAS). Functional results were assessed as well as ankle range of motion (ROM). Clinical outcomes used where the Short Form SF-12 Quality of Life score, the American Foot and Ankle Society (AOFAS). The imaging follow-up included ankle radiographs done at 6, 12 and 24 months. Radiological parameters were angles??(normal values 90 +- 2),?? (normal value 85 +- 2),??? normal values 20 +- 2) and TTratio? normal values: 27% to 42%). Results: The study included 31 ankles of TM Ankle Replacement in 31 consecutive patients over a period of 2 years (2013–2015). Out of 31 patients, 13 were females and 18 were males (average age 49.4 years, range, 30–75 years). All procedures were performed by a single surgeon. The ROM plantarflexion and dorsiflexion improved significantly (p <0.001) at the last follow up. The mean VAS pain score decreased significantly from 7.42 points (range 4 – 10 points) preoperatively to 1.42 points (range, 0 - 3 points) at the time of the latest follow-up (p <0.001). AOFAS and SF-12 scores both improved from postoperatively to the last follow up. (Table 1). We noted stable implants based on our radiographic parameters, with no corrections loosening. (Table 2) Conclusion: Our study evaluated the new fixed bearing Zimmer TM total ankle replacement approved by the US FDA in 2012 and is the first studies to evaluate the clinical and radiographic outcomes of this prosthesis. Of 31 ankles treated with a new transfibular arthroplasty system, only two asymptomatic fibular delayed union were registered. No implant failure was noted at 24 months postoperatively. Four ankles underwent secondary surgery for symptomatic fibular hardware with good outcome. The findings suggest that this total ankle system is safe and effective at short-term follow-up.


2019 ◽  
Vol 4 (4) ◽  
pp. 2473011419S0020
Author(s):  
Thos Harnroongroj ◽  
Lauren Volpert ◽  
Daniel Sturnick ◽  
Carolyn Sofka ◽  
Scott J. Ellis ◽  
...  

Category: Ankle Arthritis Introduction/Purpose: Initial implant fixation is critical for long-term success of total ankle replacement (TAR). One important factor which contributes to implant stability is the quality of the surrounding bone. Previous studies characterized a decrease in bone density with increasing distance from the level of the joint in the tibia and talus in non-arthritic ankles. However, ankle arthritis affects bone density remains unclear. The objective of this study is to compare the bone density in patients with and without ankle arthritis as a function of resection level from the joint. We hypothesized that there would be no difference in bone densities at each resection level between groups and bone density would decrease with greater distance from articular surface in both groups. Methods: We retrospectively reviewed 93 end-stage ankle arthritis patients with available preoperative non-weight bearing ankle computed tomography scans (CT)(Group A) and identified another cohort of 83 patients with non-arthritic ankles as a demographic-matched control group(Group B). Patients with retained ankle hardware, history of osteomyelitis, osteoporosis, and cysts greater than 1 cm in diameter at the ankle were excluded. There was no difference in term of gender, age and body mass index (BMI) between the groups(Table 1). The ROI tool in Sectra IDS7 picture archiving and communication system (PACS) was used to calculate Hounsfield Unit (HU) values in the cancellous region of the tibia and talus around the ankle joint. Measurements were obtained on axial CTs from 6 mm to 12 mm above the distal tibial plafond, and from 1 mm to 4 mm below the talar dome. The HU measurements and percentage decrease of HU values at each level were compared between groups. Results: Patients with ankle arthritis demonstrated significantly greater bone density than the control group between 6 mm and 10 mm from the joint in the tibia. There was no significant difference in bone density between 10 mm and 12 mm from the joint on the tibia, and at all levels in the talus between groups (Table 1). In both groups, bone density decreased significantly at each successive level from the joint for the tibia and talus. In addition, the percentage decrease of HU values at each relative level was the same in both groups. Conclusion: Patients with ankle arthritis demonstrated greater bone density at 6 mm to 10 mm from the joint in the tibia compared to demographic-matched controls. The increased bone density close to the joint may stem from bone eburnation that occurs as part of the arthritic process. In TAR, a tibial bone resection between 6 mm and 10 mm may provide improved initial stability of the implant. Contrary to traditional thinking, fixation into the talus may be of less concern.


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