Mobile Bearing Research Articles

A well performing medial fixed bearing UKA with promising survivorship at 15years.

Unicompartmental knee arthroplasty (UKA) accounts for 10% of knee arthroplasty procedures in Europe. Fixed bearing UKA designs have shown favorable survivorship in registries when compared with mobile bearings. This study analyses long-term follow-up of patients with a medial fixed bearing metal backed tibial UKA and reports 15years survivorship and clinical outcomes. Data were collected prospectively for 148 medial unicompartmental fixed bearing metal backed UKAs implanted in 148 patients in two high volumes knee arthroplasty centers between January 2005 and December 2007. The indication was osteoarthritis in all but 2 patients. Patients' reported outcome scores were documented at last follow up. The mean patient age at time of surgery was 65years. At final follow up, outcome and survivorship data were collected for 124 medial fixed bearing UKAs. Thirteen patients underwent revision; average time to revision was 77months (SD 35.31). The Kaplan-Meier analysis demonstrated a survivorship of 97.65% at 69months and of 89,52%. at 120months and 173months of follow-up. When revisions for infection were excluded, the survivorship of the implant was 90.3% at the last of follow up. The mean OKS was 43.02 (SD 5.1) at the last follow-up, and the mean FJS was 77.6 (SD 6.9). This Medial fixed bearing metal backed UKA demonstrates promising long-term survivorship and patient outcomes. It appears to be a suitable and reasonably lasting option for the treatment of medial compartment OA.

Effect of tibial component overhang on survivorship in medial mobile-bearing unicompartmental knee arthroplasty

BackgroundSome studies have shown that the position of the tibial component in Oxford unicompartmental knee arthroplasty with a mobile bearing will affect the clinical outcome of patients. Hence, our study aimed to investigate the relationship between the overhang distance of the tibial component and the survival of the implant. MethodsA retrospective analysis of patients who underwent unicompartmental knee arthroplasty at the same institution from 2014 to 2018 was presented. The study was divided into three groups: minor underhang group (underhang between −3 and 0 mm); minor overhang group (overhang 0–3 mm); and major overhang group (overhang ≥ 3 mm). Demographic and clinical profile characteristics of each group were compared, and survival curves of each group were also compared using Kaplan–Meier and modeled using multivariate Cox regression. ResultsA total of 351 knees were included in this study with a minimum follow up of three years and a mean follow up of 4.8 ± 1.5 years. The revision rates in each group were 3.6% (minor underhang group), 2.7% (minor overhang group), and 20.9% (major overhang group) (P < 0.001). From the three groups’ cumulative survival rates, the major overhang group was significantly lower than the other two groups (log rank P < 0.001). Multivariate Cox regression showed an association between the major overhang group and implant survival rate (hazard ratio = 7.515, 95% confidence interval = 2.500–22.593, P < 0.001) ConclusionThe risk of revision will increase if the tibial component overhangs more than 3 mm medially. Moreover, the reasons for revision are generally bearing dislocation and aseptic loosening.

Mid term outcome of total knee arthroplasty using sub vastus approach and mobile bearing rotating platform implant design: A prospective study

In orthopaedic surgery, long-term outcome and prognosis are very crucial. Surgical methods to the knee joint and its surrounding structures vary, but they are all designed to provide the best access to a pathological area while protecting vital surrounding tissues. A perfectly aligned knee is required for installing a rotating platform device, which MPA can easily create. The subvastus method, on the other hand, allows for a perfect lateral exposure and a completely positioned knee.Currently, the medial patellar approach is favoured for Total Knee Replacement, however our theory suggests that the lateral corner can be better viewed with the subvastus approach, making it a superior option for Rotating Platform Device insertion in varus, valgus, and stiff knee situations. To determine the outcome of subvastus approach in all types of knee pathologies using mobile bearing rotating platform implant design. We conducted prospective analysis of patients with limited preoperative ROM (flexion ≤90°) of the knee who underwent TKA using subvastus approach and presenting the 6 months results. There were a total 60 patients (60 knees) with mean age 63 (range 49–79 years) years. The mean preoperative flexion was 44°. Postoperatively knee flexion improved by mean 95° (P &amp;#60; 0.05) which was significant as assed by paired t-test. The mean knee society score improved from 34 (range 20–60) preoperative to 78 (range 70–90) postoperatively (P &amp;#60; 0.05). Our findings show that employing the subvastus method, gratifying TKA results can be achieved in varus, valgus, and stiff knee cases with restricted preoperative ROM while maintaining the benefits of early mobilisation, reduced post-operative discomfort, and patient satisfaction.

Mobile Bearing versus Fixed Bearing for Unicompartmental Arthroplasty in Monocompartmental Osteoarthritis of the Knee: A Meta-Analysis.

Introduction: Whether mobile-bearing (MB) unicompartmental knee arthroplasty (UKA) performs better than fixed-bearing (FB) implants in patients with monocompartmental osteoarthritis (OA) still remains unclear. Therefore, a meta-analysis comparing MB versus FB for UKA was conducted to investigate the possible advantages of MB versus FB in patient-reported outcome measures (PROMs), range of motion (ROM), and complications. We hypothesised that the MB design performs better than FB. Methods: This systematic review was conducted according to the 2020 PRISMA guidelines. In December 2021, PubMed, Web of Science, Google Scholar, and Embase were accessed, with no time constraints. All the clinical investigations comparing MB versus FB bearing for UKA were accessed. Only studies published in peer-reviewed journals were considered. Studies reporting data on revision settings were excluded, as were those combining unicompartmental and total knee arthroplasty. Results: Data from 25 studies (4696 patients) were collected; 58% (2724 of 4696 patients) were women. The mean length of follow-up was 45.8 ± 43.2. The mean age of the patients was 65.0 ± 5.6 years. No difference was found in range of motion (p = 0.05), Knee Scoring System (p = 0.9), function subscale (p = 0.2), and Oxford Knee Score (p = 0.4). No difference was found in the rate of revision (p = 0.2), aseptic loosening (p = 0.9), deep infections (p = 0.99), fractures (p = 0.6), and further extension of OA to the contralateral joint compartment (p = 0.2). Conclusion: The present meta-analysis failed to identify the possible superiority of the MB implants over the FB for UKA in patients with monocompartmental knee osteoarthritis. Long observational investigations are required to evaluate possible long-term complications and implant survivorship. These results should be interpreted within the limitations of the present study.

Long-Term Clinical Performance of an Uncemented, Mobile Bearing, Anterior Stabilized Knee System and the Impact of Previous Knee Surgery

BackgroundThe aim of this study is to report long-term survival and patient-reported outcome measures (PROMs) of the uncemented low contact stress total knee system and explore the potential association between prior knee surgery and outcomes. MethodsA total of 1,289 procedures in 1,068 patients performed between 2000 and 2010 (mean follow-up 11.1 years) were retrospectively identified. All patients received an uncemented, mobile bearing, anterior stabilized (cruciate sacrificing) knee implant with a porous coating on the bone-prosthesis surface. Implant survival was calculated using competing risk analyses at 5, 10, and 15 years. PROMs include the Oxford Knee Score, Knee Society Score (domain function), EuroQol 5D-3L, and Numeric Rating Scale for pain during rest and activity, and for overall satisfaction. The association between previous surgery (no surgery versus meniscectomy versus arthroscopy versus corrective osteotomies) and implant survival was assessed with multivariable Cox proportional hazards analysis; the association with PROMs was assessed with multivariable linear regression analyses. ResultsSurvival after 5, 10, and 15 years was 97.0% (95% CI 96.0-98.0), 96.3% (95% CI 95.3-97.3), and 96.0% (95% CI 94.8-97.2), respectively. The most common reason for revision was aseptic loosening of the tibial tray (23/49 revisions, 47%). All PROMs were comparable with the reference values of the Dutch Arthroplasty Register. History of knee surgery prior to TKA was not associated with survival or PROMs. ConclusionThe low contact stress uncemented mobile bearing knee implant provides excellent survival and patient satisfaction in our cohort. Previous surgery does not seem to compromise results in our population.

Bearing Separation From the Lateral Wall of the Tibial Component Is a Risk of Anterior Dislocation of the Mobile Bearing in Oxford Unicompartmental Knee Arthroplasty

Bearing dislocation is a serious complication after Oxford unicompartmental knee arthroplasty. Bearing separation from the lateral wall can cause it to spin (90° horizontal rotation) and eventually dislocate because there is just a 2 mm difference in height in both the lateral and medial sides from the bottom of the bearing, compared with the anterior (5 mm) and posterior (3 mm) sides. The details of this problem have not been previously examined. Twenty-one dislocations in 12 patients were retrospectively analyzed. Bearing separation was defined as the bearing position being sufficiently distant from the lateral wall of the tibial component to allow spinning. We analyzed the incidence of separation, the direction and the recurrence of the dislocations, and their causes and treatments. Five of the 12 patients had separation. Of the total of 21 dislocations, 11 occurred in cases of separation (52%). Seven of 11 anterior dislocations were found to have separation, whereas nine of 13 posterior dislocations occurred without separation (P= .0237). Three of 5 patients with separation had recurrence of dislocation, and eventually 2 underwent revision to fixed-bearing unicompartmental knee arthroplasty. Bearing separation from the lateral wall of the tibial component can cause bearing dislocation, especially in an anterior direction. To prevent separation, the wall-bearing distance should be evaluated before the keel slot preparation, with manipulation as necessary. Conversely, posterior dislocation was predominant in our nonseparation cases.

Effects of a 1-mm difference in bearing thickness on intraoperative bearing movement and kinematics in Oxford unicompartmental knee arthroplasty

BackgroundThe choice of mobile bearing (MB) thickness is essential for obtaining successful results after mobile-bearing Oxford unicompartmental knee arthroplasty (UKA). This study aimed to investigate the effects of a 1-mm difference in bearing thickness on intraoperative MB movement and intraoperative knee kinematics in Oxford UKAs.MethodsWe prospectively investigated the effects of a 1-mm difference in bearing thickness on intraoperative MB movement and knee kinematics in 25 patients who underwent Oxford UKAs when surgeons didn’t know which bearing thickness to choose with 1-mm difference. A trial tibial component that was scaled every 2 mm was used to measure the intraoperative MB movement, and the tibial internal rotation relative to the femur and the knee varus angle was simultaneously evaluated using the navigation system as the knee kinematics. We separately evaluated sets of two MB thicknesses with 1-mm differences, and we compared the intraoperative parameters at maximum extension; 30º, 45º, 60º, and 90º flexion; and maximum flexion between the thicker MB (thick group) and the thinner MB (thin group).ResultsThe MB in the thin group was located significantly posteriorly at 90º flexion compared with that in the thick group; however, there were no differences at the other flexion angles. There was significantly less tibial internal rotation in the thin group at 90º flexion than that in the thick group; however, there were no differences at the other flexion angles. The knee varus angles in the thick group were significantly smaller than those in the thin group by approximately one degree at all angles other than at 30º and 45º flexion.ConclusionThe thicker MB could bring the less posterior MB movement and the more tibial internal rotation at 90º flexion, additionally the valgus correction angle in the thicker MB should be paid attention. These results could help surgeons to decide the thickness of MBs when they wonder the thickness of MB.

Personalized Hip Joint Replacement with Large Diameter Head: Current Concepts.

Hip arthroplasty is a common procedure in elective orthopaedic surgery that has excellent outcomes. Hip replacement surgery aims to create a “forgotten” joint, i.e., a pain-free joint akin to a native articulation. To achieve such goals, hip arthroplasty must be personalised. This is achieved by restoring: the centre of rotation of the native hip; leg length equality; femoral offset; femoral orientation; soft tissue tension; joint stability with an unrestricted hip range of motion; and having appropriate stress transfer to the bone. In addition, the whole pathway should provide an uneventful and swift postoperative recovery and lifetime implant survivorship with unrestricted activities. At our institution, the preferred option is a personalized total hip arthroplasty (THA) with a large diameter head (LDH) using either monobloc or dual-mobility configuration for the acetabular component. LDH THA offers an impingement-free range of motion and a reduced risk of dislocation. The larger head-neck offset allows for a supraphysiologic range of motion (ROM). This can compensate for a patient’s abnormal spinopelvic mobility and surgical imprecision. Additionally, LDH bearing with a small clearance exerts a high suction force, which provides greater hip micro-stability. With appropriate biomechanical reconstruction, LDH THA can restore normal gait parameters. This results in unrestricted activities and higher patient satisfaction scores. We use LDH ceramic on ceramic for our patients with a life expectancy of more than 20 years and use LDH dual mobility bearings for all others.

Midterm Outcomes in Lateral Unicompartment Knee Replacement: The Effect of Patient Age and Bearing Choice.

Isolated lateral compartment knee osteoarthritis (OA) affects between 7 and 10% of patients with knee OA. Although lateral unicompartmental knee arthroplasty (UKA) is an accepted treatment to manage this condition, it is performed relatively infrequently. The aim of this study was to evaluate the mid-term survivorship, radiographic outcomes, and patient-reported outcome measures (PROMs). We performed a retrospective review of a prospectively maintained database of consecutive isolated lateral UKAs performed by a single surgeon at an academic institution between September 2007 and December 2015. Our primary outcome was failure defined as revision surgery to total knee arthroplasty (TKA). Secondary outcomes included any additional surgery for any other reason. Forty-nine consecutive patients (27 females) with median age of 54.7 years (45.2-82.2) met the inclusion criteria. The survival rate for the whole cohort was 86.1% (95% confidence interval [CI]: 73.2-99.0) at 10 years as defined by conversion to TKA. There were a total of four lateral UKAs (all mobile bearings) revised to TKAs. The entire cohort demonstrated statistically significant improvements from preoperative PROMs compared with the most recent postoperative PROMs including the Western Ontario and McMaster Universities Osteoarthritis Index, Knee injury and Osteoarthritis Outcome Score, and Tegner activity scale at a median 8.8 (1.7-12.2) years follow-up. Patients with mobile bearing underwent higher revision to TKA and reoperation for all indications compared with fixed-bearing lateral UKA. In this relatively young cohort, lateral UKA yielded acceptable long-term survival and satisfactory improvement in functional outcomes. Patients who had fixed-bearing implants had similar improvement and trended toward lower revision rates than those with mobile-bearing implants. Level III therapeutic: retrospective Study was performed.

Application of a robotics path planning algorithm to assess the risk of mobile bearing dislocation in lateral unicompartmental knee replacement

Due to ligament laxity, bearing dislocation occurs in 1–6% of Oxford Domed Lateral (ODL) replacements with most dislocations occurring medially. Dislocations were studied using a previously built mechanical rig, however testing using the rig was inefficient. The aim of this study was to develop a better tool that was more reliable and efficient. An established robotics software package, the Open Motion Planning Library, was modified to accept the ODL components. Using a robotics path planning algorithm, the mobile bearing was allowed to find a way out from between the femoral and tibial components i.e. to dislocate. Testing assessed a range of clinically relevant positions of the femoral component relative to the tibial component. Dislocations were labelled as medial, lateral, anterior or posterior depending on the dislocation direction. The Distraction to Dislocation (DD) measured the minimum vertical distraction of the femoral component from the tibial component for a dislocation to occur. Results were validated against the mechanical rig. Statistical analysis of medial dislocation showed excellent agreement with an intraclass correlation value of 0.993 (95% CI 0.982–0.998). All DDs from the dislocation analysis tool were within 1 mm of the mechanical rig DDs with results sharing a remarkably similar trend. The robotics dislocation analysis tool output DDs which were marginally higher than the manual mechanical rig: 0.50 mm anteriorly, 0.25 mm posteriorly and 0.50 mm laterally. Medially, the computational DD differed on average by 0.09 mm (stand deviation: 0.2026 mm). Our study describes the development and validation of a novel robotics dislocation analysis tool, which allows mobile bearing dislocation risk quantification. The tool may also be used to improve surgical implantation parameters and to assess new implant designs that aim to reduce the medial dislocation risk to an acceptable level.

META analysis of mobile bearing and fixed bearing unicondyle replacement for medial knee osteoarthritis

To evaluate of the clinical effects of mobile-bearing(MB) and fixed-bearing(FB) unicompartmental knee arthroplasty(UKA) in the treatment of knee osteoarthritis by Meta-analysis. The literature on FB UKA and MB UKA in the treatment of knee osteoarthritis in PubMed, CNKI, Wanfang, Cochrane and EMBASE database were searched by computer from January 2000 to April 2020. According to the inclusion and exclusion criteria, two authors were selected independently and the selected literature was evaluated for quality.After literature data were extracted, Review Manager 5.3 software was used to analyze knee function score, postoperative activity, revision rate, polyethylene wear rate, pad dislocation, aseptic loosening, postoperative pain, knee arthritis progression, mechanical shaft alignment of lower limbs, and imaging clarity line respectively. A total of 13 literatures were included in this meta-analysis, including 2 randomized controlled studies and 11 cohort studies. A total of 1 871 patients were included, including 913 in FB UKA group and 958 in MB UKA group. Meta analysis results showed that:postoperative knee joint function score[MD=-0.84, 95%CI(-1.46, -0.21), P=0.008] and postoperative knee joint range of motion [MD=-1.51, 95%CI(-2.84, -0.18), P=0.03] in FB UKA group were better than those in MB UKA group. Compared with FB UKA group, MB UKA group had a higher lower limb mechanical axis alignment rate[OR=2.08, 95%CI(1.27, 3.39), P=0.003], and the wear rate of polyethylene [OR=0.11, 95%CI(0.01, 0.91), P=0.04] was lower. There were no differences between two groups in the renovation rate [OR=1.16, 95%CI(0.75, 1.80), P=0.50), liner dislocation rate[OR=3.78, 95%CI(0.93, 15.29), P=0.06], aseptic loosening [OR=2.11, 95%CI(0.81, 5.51), P=0.13], postoperative pain[OR=1.13, 95%CI(0.37, 3.43), P=0.83], osteoarthritis progression[OR=1.28, 95%CI(0.67, 2.47), P=0.46)and imaging radiolucent line[OR=1.62, 95%CI(0.09, 30.22), P=0.75]. FB UKA has a higher postoperative functional score and range of motion.MB UKA has more advantages in the correction of lower limb mechanical axis, and the wear rate of polyethylene is also lower. There was no significant difference between the two groups in revision rate, dislocation of the liner, aseptic loosening, postoperative pain, progression of osteoarthritis, and postoperative translucency.

Comparative retrieval analysis of contemporary mobile and fixed unicompartmental knee bearing designs

There are two different concepts behind Unicompartmental Knee Replacement (UKR). Mobile bearings, as exemplified by the Oxford UKR, and fixed bearings, as exemplified by the Physica ZUK. These are the two most commonly implanted UKRs in the UK. For the first time, a comparison of the tribological features of 19 explanted Oxford and 19 explanted Physica ZUK UKRs was undertaken. Surface damage on the polyethylene (PE) inserts of the Oxford and Physica ZUK cohorts were assessed using an established semi-quantitative scoring method. The femoral components of both cohorts were assessed using a non-contact 3D profilometer to measure roughness values. It was found that the PE inserts of the Oxford cohort (22.54 ± 9.14) had statistically significant greater damage scores than the Physica ZUK cohort (16.50 ± 5.17) (p = 0.04). However, the femoral components of the Oxford cohort showed lower roughness values than the Physica ZUK cohort (p = 0.00). This is the first study that reports a comparative roughness analysis between retrieved Oxford and Physica ZUK UKR designs.

Late Failure of a Polyethylene Unicompartmental Knee Insert -Retrieval Analysis Protocol and Results

This study reports the investigation of a degraded polyethylene insert retrieved after the catastrophic failure of a mobile bearing knee implant, occurred after a traumatic event and leading to a late revision. Understanding wear mechanisms of polyethylene components is important to improve the implants for joint replacement. This model of unicompartmental arthroplasty, due to its mobile, congruent insert and design, has the potential to attain low rates of wear, leading to an improved survival of the prosthesis over fixed-bearing knee implants. During the surgical technique, however, it is critical to avoid any source of impingement or incongruent articulation, as this are associated with increased rates of polyethylene wear and may contribute to the early necessity for revision surgery. The investigated insert presented a macroscopic fragmentation, surface and bulk defects and debris. Characterization of the retrieved polyethylene implant fragments was performed by macroscopic examination, by scanning electron microscopy and Fourier transform infrared spectroscopy. Due to a systematic retrieval analysis according to current standards, we can question that, in our case, third body wear is rarely pure bone or pure cement debris related but a combination of the two mentioned. The combination enhanced contribution of polyethylene debris in severe wear initiation and progression. Complete examination of the explants exhibiting breakage or severe wear may help in understanding pathogenic ways of failure in unicompartmental knee.

Ten-Year Outcomes of MobilityTM Total Ankle Replacement Confirms Radiological Loosening is Not Conclusive or Reliable for Long Term Survival Analysis

Category:Ankle; Ankle ArthritisIntroduction/Purpose:Different designs of Ankle replacement are being performed nowadays, long-term outcome data is the better way to understand these implants behaviour and survival. We compared the differences in demographic data, clinical, Radiological, and patient-reported outcomes among patients who underwent total ankle replacement performed with use of the uncemented stemmed mobile bearing (MOBILITY) Total Ankle System with 10 year follow up.Methods:We analysed 156 (15 bilateral ankles (3 non-mobility) Mobility TAR (of which 41, 45, 22 for OA, PTOA, Inflammatory arthritis respectively). Mean age 61.7 (SD 11.4) (Range 33-90). 70 Ankles had 10 years of follow up, 115 had 5 years follow up,. 96 were males, with 30 patients deceased before 10 years follow up covering 33 ankles. All from our local registry looking at the patient's demographic data, and patient-reported outcomes as measured with use of WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index), the Foot and Ankle Outcome Score (FAOS), the 36-item Short-Form (SF-36) Health Survey, clinical and radiological outcomes and patient-satisfaction scores, collected preoperatively and at 1,3,5 and 10 years postoperatively.Results:Of the 156 ankles18 had wound complications after surgery two only needed surgical debridement. 5 CRPS,16 stress fractures 2 only requiring surgical fixation,11 had subsequent STJ fusion.77 had no signs of radiolucency. The rest had some degree of radiolucency on x-ray (55% on the tibia side) only 11 where symptomatic to require further surgery (6 revised to another TAR, 2 fused, and3 required bone grafting). 11 needed osteotomies after surgery. Aseptic loosening and infection are the least common complications requiring revision. There was significant improvement in WOMAC for pain (35.9 to 67.9), function (40.6 to 66.9) and stiffness (39.4 to 62.5) from pre-op to 1 year (p<0.05), this was maintained for 10 years. Although improvement noted in the composite physical component of SF=36 (28.3 to 34.5) there was no significant increase for composite mental component score. 77.5% reported satisfaction from pain relief,72.4% with return to ADL, 40% were dissatisfied with return to recreational activities and15.5% reported dissatisfaction with overall results of surgery. Mobility TAR shown about 86% survival in our 10 years cohort.Conclusion:With improved PROMS at 1,3,5,10 years showing Patient satisfaction score at 10 years indicates that uncemented mobile bearing implants have good long-term results, osteolysis and aseptic loosening as the least common cause of revision. It is pertinent that reporting of radiological loosening in an uncemented ankle is not conclusive or reliable for long term survival analysis.

Does Sagittal Tibiotalar Alignment of TAR Predict Failure?

Category:Ankle ArthritisIntroduction/Purpose:The long term outcome of total ankle replacement is contingent on restoring the anatomic tibiotalar alignment of the ankle joint. Prior studies have mainly looked at the effect of coronal and hindfoot alignment of TAR on outcome and failure with few studies focusing on the effect of sagittal tibiotalar alignment. From these, we know that sagittal alignment has a greater impact on joint mechanics and that proper positioning of the talar component in the sagittal plane results in greater postoperative pain relief and better functional outcome, especially ankle range of motion. The goal of this study was to define a sagittal radiographic value that predicts failure in TAR.Methods:We analyzed the data of a retrospective patient cohort of consecutive TAR patients, which were treated from 2004 and 2011. Patients with two types of prosthesis were included, Salto Talaris (fixed bearing) and STAR (mobile bearing). All measurements were completed by two blinded observers, including the sagittal distal tibial articular angle (sDTAA), the lateral talar station (LTS) and the talar component inclination angle (γ angle). A total of 90 patients were included, 51 were male and 39 female patients. Seventy-seven patients received a Salto and 13 patients a STAR prosthesis. The average age was 63.7 years.Results:The mean sDTAA was 83.9 degrees and the mean γ angle was 21 degrees, both without significant difference in the two different prosthesis designs. A significant association (p=0.03) between post-op LTS as a continuous variable per unit increase and clinical failure was demonstrated, which included all the revision cases, with an odds ratio of 1.25. In addition a significant association (p=0.03) between increased LTS and sDTAA change of >5°, which is indicative of anterior subsidence, was shown. This was associated with an odds ratio of clinical TAR failure of 1.27.Conclusion:The abnormal radiographic post-op lateral talar station appears to predict clinical TAR failure and correlates with the abnormal sDTAA; the anterior translated talus loads the anterior tibia leading to anterior subsidence of the prosthesis. Limitation of this study is the inclusion of two different types of prosthesis designs.

Total Ankle Replacement vs Ankle Arthrodesis (TARVA): A Randomised, Multi-Centre Trial in Patients Over 50 with End Stage Ankle OA, Comparing Clinical and Cost-Effectiveness

Category:Ankle Arthritis; Ankle; OtherIntroduction/Purpose:Both ankle replacement and ankle arthrodesis are offered as treatments to patients with end stage ankle osteoarthritis. Systematic reviews have confirmed that both procedures are effective but there has never been a robust randomised multicentre level I study comparing the two treatments. Our objective was to investigate and compare the clinical and cost effectiveness and complication rates of ankle replacement against ankle arthrodesis in the treatment of end-stage ankle osteoarthritis in patients aged 50-85 years.Methods:17 NHS centres and 35 surgeons across the United Kingdom participated. Formal Ethics committee approvals were obtained. A Trial Management Group was overseen by a Trial Steering Committee, and an Independent Data Monitoring Committee. Randomisation was carried out using a secure on-line service and was stratified by surgeon and the presence or absence of adjacent joint OA (based on an independently reviewed preoperative MRI scan). Participants were randomised 1:1 to either TAR or ankle fusion. The primary outcome was the change in the Manchester Oxford Foot & Ankle Questionnaire (MOXFQ) walking/standing domain scores between pre-operation and 52 weeks post-operation. Secondary outcomes measures included FAAM; FAAM (ADL); and Sport subscale scores. Quality of life was measured using the EQ-5D-5L. Total range of motion was measured using a validated method. Radiological parameters and adverse events were captured. Health economic analysis used mean incremental cost per quality-adjusted life years (QALY) gained.Results:1600 patients were screened for eligibility. 330 participants were consented and 303 were randomised; 282 underwent surgery and attended follow-up visits. Mean age was 68 years (71% male). The aetiology of OA was post-trauma in 60%, with 6% patients having inflammatory OA. 42% had MRI evidence of OA in the adjacent joints. The groups were well balanced at baseline on all other parameters including deformity, range of motion and baseline clinical and quality of life scores.42% had MRI evidence of OA in the adjacent joints. 54% TARs used were fixed bearing; 46% were mobile bearing. 61% of fusions were performed arthroscopically. We present all outcomes including adverse effects (death; thromboembolic events; reoperation and revision); radiological findings; and range of motion. We also present subgroup analyses looking at the performance of fixed versus mobile bearing implants; differences by age; and by the presence or absence of adjacent joint OA.Conclusion:This is the first publicly funded, multicentre, prospective, randomised clinical trial comparing the clinical and cost effectiveness of ankle replacement against ankle fusion. It is also the first study in surgery to have detailed prospectively captured health economic data to be able to feed into the reimbursement discussions on these life transforming treatments. Due to contractual requirements of the funders the formal results cannot be released until the final report has been submitted for peer review which will not happen until the end of April 2021. The paper is submitted on behalf of the TARVA Study Group.

Особенности хирургической тактики в лечении переломов проксимального отдела бедренной кости у геронтологических пациентов

The paper is dedicated to improving the treatment outcomes and consequences in elderly patients with femoral neck fracture by improving the diagnostics, osteosynthesis and total hip arthroplasty. The main causes and factors influencing the complication rates and final treatment outcomes in elderly patients with femoral neck fracture were identified. The evidence based diagnostic and treatment algorithm for such patients was designed. The proposed treatment system helped to reduce lethality, general and local complication rates among these patients. The active surgery helps to solve massive healthcare problems by easing the pain in elderly patients, restoring the hip joint mobility and weight bearing ability of extremity, enhancing independent living skills, and improving vitality and psychological state.

Comparison of Fixed-Bearing and Mobile Bearing Total Knee Arthroplasty in and around Kanchipuram Population

Comparison of Fixed-Bearing and Mobile Bearing Total Knee Arthroplasty in and around Kanchipuram Population

Effect of Packaging on Polyethylene Fractures, Implant Survivorship and Cyst Formation in Mobile Bearing Total Ankle Replacements

Category:Ankle Arthritis; AnkleIntroduction/Purpose:The Scandinavian Total Ankle Replacement (STAR) is the most widely used mobile bearing total ankle arthroplasty (TAA) in the US. The polyethylene component is ultrahigh molecular weight polyethylene and is designed to articulate with both the tibial and talar component. Initial data on the STAR in the US reported polyethylene fracture rates of greater than 10% as well as a concern for cyst formation due to osteolysis. The manufacturer changed the packaging to foil to prevent potential oxidation of the polyethylene, which could predispose the polyethylene to failure. The objective of the study was to evaluate a cohort of patients with STAR performed before and after converting to foil packaging to determine if there is a difference in polyethylene survivorship and cyst formation.Methods:All primary TARs performed by the senior author from 2010-2017 were reviewed. Patients with a minimum 48 month follow up were included in the study. The two groups were stratified by those performed prior to August 2014 (PRE) and those performed after August 2014 (POST). Preoperative and most recent postoperative alignment was determined on weight bearing radiographs. The outcomes included polyethylene fractures and cyst formation in the two groups. Cysts were defined as those measuring greater than 1cm2 on plain radiographs. Patients were recommended to have surgery if cyst volume was greater than 2cm2. Chi-squared tests were used to detect significant differences in the rate of cyst formation between the two groups. Paired t- tests were used to determine difference in preoperative versus postoperative alignment, follow up length, and polyethylene component thickness and patient age at time of procedure between the two groups.Results:The PRE group had 35 patients with an average follow up of 75 months (range 48-118). The POST group had 15 patients with average follow up 55 months (range 48-60). There was no difference in preoperative versus postoperative radiographic alignment between the groups (p>0.05). Cysts were present in 9 (26%) patients in the PRE group versus 4 patients (26%) in the POST group. Nine patients (26%) needed a second surgery due to cyst formation in the PRE group versus two (16%) in the POST group (p>0.05). Four patients (11%) had a fracture of the polyethylene in the PRE group with an average thickness of 6.7mm (range 6-9) and 77 months (range 68-84) versus zero in the POST group. The average time to polyethylene exchange for cyst(s) or polyethylene fracture was 58.3 months.Conclusion:This study suggests that changes in packaging to limit oxidation of the polyethylene from plastic to foil did not appear to represent a difference in periprosthetic cyst formation. However, there was a trend for additional surgery related to periprosthetic cysts and increased risk for polyethylene fracture in the PRE group. These results could suggest the potential for oxidation changes that alter the wear characteristics and fragility of the polyethylene component. Confounding factors could include postoperative time and component thickness. Further investigation and longer follow-up will be needed to further delineate oxygenation impacts on TAA polyethylene components.

Motion is Maintained at the Tibial and Polyethylene Component Interface in a Mobile-Bearing Total Ankle Arthroplasty at Mid and Long-Term Follow-Up

Category:Ankle Arthritis; Ankle; HindfootIntroduction/Purpose:Normal biomechanics of the ankle joint includes sagittal motion, but also anterior-posterior (AP) translation (1mm) as well as axial rotation (5-8 degrees). Sagittal motion is well described in total ankle arthroplasty (TAA), however, current understanding of mobile-bearing motion at the tibial-polyethylene interface in TAA is limited to AP motion and short-term data on axial rotation. The purpose of our study was to determine if polyethylene components maintain mobility adjacent to the tibial component in mobile bearing TAA at mid and long-term follow-up in both the sagittal and axial planes in patients more than 48 months post-operatively.Methods:Patients who were a minimum of 48 months postoperative from a third-generation mobile-bearing TAAwere identified. Fluoroscopic images perpendicular to the tibial component were saved at maximum internal and external rotation on AP, and the lateral images were saved in maximum plantarflexion and dorsiflexion. Sagittal range of motion and AP translation of the polyethylene component were measured from the lateral images. Axial rotation was determined by measuring the relative position of the two wires within the polyethylene component on AP internal and external rotation imaging. This relationship was compared to a table previously developed from fluoroscopic images taken at standardized degrees of axial rotation of a nonimplanted polyethylene with the associated length relationship of the two imbedded wires. Total axial motion was determined by the difference between angle value determined for maximum internal and external rotation.Results:Eight patients were included in this investigation, 5 (62.5%) were female and average age was 72.6 (range, 59-83) years. Time from surgery averaged 94.2 (range, 54.7-118.6) months. Total sagittal range of motion between the talar and the polyethylene component averaged 20.3 (range, 10-30) degrees. All patients (100%) maintained motion at the tibia-polyethylene interface. Axial motion for total internal and external rotation of the polyethylene component articulation on the tibial component averaged 5.3 (range, 2-12) degrees. AP translation of the polyethylene component relative to the tibial component averaged 1.1 (range, 0.4-2.6) mm during plantarflexion and dorsiflexion. There was no relationship between axial rotation or AP translation of the polyethylene component and ankle joint range of motion (P >.05).Conclusion:To our knowledge, this is the first investigation to measure axial and sagittal motion of the polyethylene component in mobile bearing TAA at the tibial implant interface in patients at mid and long-term follow-up. Based on our results, motion is maintained an average of 8 years post-operatively and concludes that a mobile-bearing TAA has the potential to fall within the parameters of normal polyaxial ankle motion several years after implantation. Such maintenance of motion may have a positive influence on gait pattern, polyethylene wear, joint reaction forces and implant longevity.