Customised individually made implants(CIM) total knee arthroplasty(TKA) are custom-made to better fit patients native anatomy and aim to improve outcomes which can be variable with conventional off-the-shelf(OTS). A systematic review and meta-analysis was conducted searching the MEDLINE and Embase databases. Studies reporting on patient reported outcome measures, clinical or radiological outcomes were included. 23 studies satisfied the search criteria (case-control studies14, case series8, cross-sectional studies1). There were 2,856(CIM) and 1,877(OTS) implants. The overall revision-rate was higher in CIM 5.9%vs3.7%OTS [OR 1.46(95% CI 0.82–2.62)]. MUA was higher in the CIM group 2.2%vs.1.1%OTS [OR 2.95(95% CI 0.95–9.13)] and overall complications rate was also higher in the CIM group 5% vs. 4.5%OTS [OR 1.45(95% CI 0.53–3.96)]. LOS was significantly shorter in the CIM group 2.9 days vs. 3.5 days [MD −0.51(95% CI −0.82–0.20)]. Pooled analysis for KSS showed no difference between CIM and OTS groups(Knee=90.5 vs. 90.6 [MD-0.27,(95% CI −4.27–3.73)] and Function=86.1 vs. 90.6[MD 1.51 (95% CI −3.69–6.70)] component of the scores. There was no significant difference in post-operative ROM between CIM and OTS groups 117.3° vs. 115.0° [MD 0.02,(95% CI −1.70–1.74)]. CIM TKAs has theoretical benefits over OTS TKAs however in this review they were associated with higher complication, MUA and revision rates with no difference in outcome scores and no improvement in target alignment. The findings of this review does not support the use of CIM over OTS prosthesis in total knee arthroplasty.Abstract
The aim of this study was to compare the actual cost of a cemented and cementless total knee arthroplasty (TKA) procedure. The cost of operative time, implants, cement, and cementing accessories were included in the overall cost of the TKA procedure. Operative time was determined from a previously published study comparing cemented and cementless implants of the same design. The cost of operative time, implants, cement, and cementing accessories was determined from market and institutional data.Aims
Materials and Methods
Patients presenting with loosening or a fracture between ipsilateral hip and knee replacements provide a unique reconstructive challenge. We present mid-term results of the cement-over megaprosthesis (COM) when managing these complex cases. A COM is cement-linked to the stem of a well-fixed existing implant. We report the largest series to date and show that this may be preferable to total femoral replacement in a cohort of patients who often have significant co-morbidities. A retrospective analysis of patients undergoing COM between 2002–2022 was performed. Primary outcomes were defined as implant survival, displayed with survival analysis. Secondary outcomes included mortality and surgical complications. Functional outcomes included Visual Analogue Score (VAS), EuroQol-5D-3L and Musculoskeletal Tumour Society (MSTS) score at one year post operatively.Abstract
Introduction
Methodology
In revision knee arthroplasty, rotating hinge implants (RHK) have been considered to result in higher complication rates and lower survivorship when compared to constrained condylar implants (CCK). The aims of this study were to compare patient reported outcome measures (PROMs), complication rates and survivorship of RHK and CCK used in revision arthroplasty at a single, high volume elective orthopaedic centre with previously validated bespoke database. One hundred and eight patients who underwent revision knee arthroplasty with either CCK or RHK and matched our inclusion criteria were identified. EQ5D, Health State and Oxford Knee Scores were collected pre-operatively and at 1 year post-operatively. Complication data was collected at 6 weeks, 6 months, 1 year and 2 years post-operatively. NJR data was interrogated, in addition to our own database, to investigate implant survival.Abstract
Introduction
Methodology
Pitting damage on implants has been reported and attributed to use of electrocautery. This study aimed to distinguish how different TKA bearing surfaces are susceptible to this type of damage and whether surgeons were aware that this damage can occur. A survey was sent to Hip and Knee Society members to determine what percentage of adult reconstructive surgeons use electrocautery after implantation of components. Three bearing surfaces for primary TKA were selected: CoCr, Oxinium, and zirconium nitride (ZrN) to be damaged by electrocautery with a monopolar (MP, Bovie) and bipolar (BP, Aquamantys) electrocautery with three different energy settings. A comparison of surface damage and backscatter elemental analysis using SEM was performed. Average roughness (Ra), maximal peak-to-valley height (Rz,), kurtosis (Rk), and skewness (Rsk) measurements were collected using a profilometer (DektakXT, Bruker, Tucson, AZ) with a 2.5µm radius stylus to assess an area of 3.8mm by 3.2mm in the central portion of the area for each MP and BP energy setting used to impart damage to the bearing surfaces. A similar undamaged area for each bearing surface was also measured for roughness parameter comparison.Introduction
Methods
Pressure to control health care costs may limit the ability of new implants to enter the market. Customized individually made (CIM) knee implants are produced from CT scans of each patient and may result in improved clinical outcomes based on early data showing less blood loss, reduced bone resection, and better implant function and alignment. Limited economic evidence suggests that the use of CIM technology may result in cost savings, particularly when post-discharge expenses are included. The purpose of this study was to evaluate real-world cost data to determine episode spending in a Medicare population receiving either CIM or off-the-shelf (OTS) implants. The Yale Center for Musculoskeletal Care and Baker Tilly Healthcare Management reviewed episode expenditures among Medicare beneficiaries who received CIM and OTS implants for TKA between 01/01/2015 and 12/31/2015. Episode costs included the pre-operative CT scan, index TKA procedure, and 12-month post-index spending for inpatient (IP), outpatient (OP), emergency room (ER), skilled nursing facility (SNF), and home health (HH) services. CIM patients were identified through a matching process utilizing de-identified patient demographic and procedural information and the presence of a CT scan 28–365 days before index. OTS patients included those without a CT scan within one year of index. CIM and OTS cohorts were propensity matched to produce comparable cohorts at a one-to-five ratio based on age range, gender, race, geographical location, and comorbidities. Average expenditure was used to calculate one-year costs of care differences between the CIM and the OTS technologies. A Generalized Linear Model (GLM) and two-part model (logistics and GLM) were used to test statistical significance.Introduction
Methods
Aims. Robotic-assisted unicompartmental knee arthroplasty (UKA) promises accurate implant placement with the potential of improved survival and functional outcomes. The aim of this study was to present the current evidence for robotic-assisted UKA and describe the outcome in terms of implant positioning, range of movement (ROM), function and survival, and the types of robot and implants that are currently used. Materials and Methods. A search of PubMed and Medline was performed in October 2018 in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Search terms included “robotic”, “knee”, and “surgery”. The criteria for inclusion was any study describing the use of robotic UKA and reporting implant positioning, ROM, function, and survival for clinical, cadaveric, or dry bone studies. Results. A total of 528 articles were initially identified from the databases and reference lists. Following full text screening, 38 studies that satisfied the inclusion criteria were included. In all, 20 studies reported on implant positioning, 18 on functional outcomes, 16 on survivorship, and six on ROM. The Mako (Stryker, Mahwah, New Jersey) robot was used in 32 studies (84%), the BlueBelt Navio (Blue Belt Technologies, Plymouth, Minnesota) in three (8%), the Sculptor RGA (Stanmore
Objectives. Bone void fillers are increasingly being used for dead space management in arthroplasty revision surgery. The aim of this study was to investigate the influence of calcium sulphate bone void filler (CS-BVF) on the damage and wear of total knee arthroplasty using experimental wear simulation. Methods. A total of 18 fixed-bearing U2 total knee arthroplasty system implants (United Orthopedic Corp., Hsinchu, Taiwan) were used.
The aims were to assess whether joint-specific outcome after total knee arthroplasty (TKA) was influenced by implant design over a 12-year follow-up period, and whether patient-related factors were associated with loss to follow-up and mortality risk. Long-term follow-up of a randomized controlled trial was undertaken. A total of 212 patients were allocated a Triathlon or a Kinemax TKA. Patients were assessed preoperatively, and one, three, eight, and 12 years postoperatively using the Oxford Knee Score (OKS). Reasons for patient lost to follow-up, mortality, and revision were recorded.Aims
Methods
Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies. In 137 robotic-assisted TKAs, extension and flexion stressed gap laxities and bone resections were measured. The primary outcome was the proportion and magnitude of medial and lateral SPI (gap differential > 2.0 mm) for KA, MA, and FA. Secondary outcomes were the proportion of knees with severe (> 4.0 mm) SPI, and resection thicknesses for each technique, with KA as reference.Aims
Methods
Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised. This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups.Aims
Methods
A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis. Overall, 50 subjects were randomized (21 EF-TKA and 23 Std-TKA in the final analysis), and had follow-up visits at six weeks, and six, 12, and 24 months to assess migration of the tibial component. Low viscosity bone cement with tobramycin was used in a standardized fashion for all subjects. Patient-reported outcome measure data was captured at preoperative and all postoperative visits.Aims
Methods
Micromotion of the polyethylene (PE) inlay may contribute to backside PE wear in addition to articulate wear of total knee arthroplasty (TKA). Using radiostereometric analysis (RSA) with tantalum beads in the PE inlay, we evaluated PE micromotion and its relationship to PE wear. A total of 23 patients with a mean age of 83 years (77 to 91), were available from a RSA study on cemented TKA with Maxim tibial components (Zimmer Biomet). PE inlay migration, PE wear, tibial component migration, and the anatomical knee axis were evaluated on weightbearing stereoradiographs. PE inlay wear was measured as the deepest penetration of the femoral component into the PE inlay.Aims
Methods
We have previously reported the mid-term outcomes of revision total knee arthroplasty (TKA) for flexion instability. At a mean of four years, there were no re-revisions for instability. The aim of this study was to report the implant survivorship and clinical and radiological outcomes of the same cohort of of patients at a mean follow-up of ten years. The original publication included 60 revision TKAs in 60 patients which were undertaken between 2000 and 2010. The mean age of the patients at the time of revision TKA was 65 years, and 33 (55%) were female. Since that time, 21 patients died, leaving 39 patients (65%) available for analysis. The cumulative incidence of any re-revision with death as a competing risk was calculated. Knee Society Scores (KSSs) were also recorded, and updated radiographs were reviewed.Aims
Methods
The aim of this study was to determine the risk of tibial eminence avulsion intraoperatively for bi-unicondylar knee arthroplasty (Bi-UKA), with consideration of the effect of implant positioning, overstuffing, and sex, compared to the risk for isolated medial unicondylar knee arthroplasty (UKA-M) and bicruciate-retaining total knee arthroplasty (BCR-TKA). Two experimentally validated finite element models of tibia were implanted with UKA-M, Bi-UKA, and BCR-TKA. Intraoperative loads were applied through the condyles, anterior cruciate ligament (ACL), medial collateral ligament (MCL), and lateral collateral ligament (LCL), and the risk of fracture (ROF) was evaluated in the spine as the ratio of the 95th percentile maximum principal elastic strains over the tensile yield strain of proximal tibial bone.Aims
Methods
This study compared the cobalt and chromium serum ion concentration of patients treated with two different metal-on-metal (MoM) hinged total knee arthroplasty (TKA) systems, as well as a titanium nitride (TiN)-coated variant. A total of 63 patients (65 implants) were treated using either a MoM-coated (n = 29) or TiN-coated (n = 7) hinged TKA (GenuX mobile bearing, MUTARS; Implantcast, Germany) versus the BPKS (Brehm, Germany) hinged TKA (n = 27), in which the weight placed on the MoM hinge is diffused through a polyethylene (PE) inlay, reducing the direct load on the MoM hinge. Serum cobalt and chromium ion concentrations were assessed after minimum follow-up of 12 months, as well as functional outcome and quality of life.Aims
Methods
Knee arthroplasty surgery is a highly effective treatment for arthritis and disorders of the knee. There are a wide variety of implant brands and types of knee arthroplasty available to surgeons. As a result of a number of highly publicized failures, arthroplasty surgery is highly regulated in the UK and many other countries through national registries, introduced to monitor implant performance, surgeons, and hospitals. With time, the options available within many brand portfolios have grown, with alternative tibial or femoral components, tibial insert materials, or shapes and patella resurfacings. In this study we have investigated the effect of the expansion of implant brand portfolios and where there may be a lack of transparency around a brand name. We also aimed to establish the potential numbers of compatible implant construct combinations. Hypothetical implant brand portfolios were proposed, and the number of compatible implant construct combinations was calculated.Aims
Methods
The aim of this study was to compare the clinical outcomes of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) during the first six weeks and at one year postoperatively. A per protocol analysis of 76 patients, 43 of whom underwent TKA and 34 of whom underwent bi-UKA, was performed from a prospective, single-centre, randomized controlled trial. Diaries kept by the patients recorded pain, function, and the use of analgesics daily throughout the first week and weekly between the second and sixth weeks. Patient-reported outcome measures (PROMs) were compared preoperatively, and at three months and one year postoperatively. Data were also compared longitudinally and a subgroup analysis was conducted, stratified by preoperative PROM status.Aims
Methods
Single-stage revision total knee arthroplasty (rTKA) is gaining popularity in treating chronic periprosthetic joint infections (PJIs). We have introduced this approach to our clinical practice and sought to evaluate rates of reinfection and re-revision, along with predictors of failure of both single- and two-stage rTKA for chronic PJI. A retrospective comparative cohort study of all rTKAs for chronic PJI between 1 April 2003 and 31 December 2018 was undertaken using prospective databases. Patients with acute infections were excluded; rTKAs were classified as single-stage, stage 1, or stage 2 of two-stage revision. The primary outcome measure was failure to eradicate or recurrent infection. Variables evaluated for failure by regression analysis included age, BMI, American Society of Anesthesiologists grade, infecting organisms, and the presence of a sinus. Patient survivorship was also compared between the groups.Aims
Methods
This study aimed to determine outcomes of isolated tibial insert exchange (ITIE) during revision total knee arthroplasty (TKA). From 1985 to 2016, 270 ITIEs were performed at one institution for instability (55%, n = 148), polyethylene wear (39%, n = 105), insert fracture/dissociation (5%, n = 14), or stiffness (1%, n = 3). Patients with component loosening, implant malposition, infection, and extensor mechanism problems were excluded.Aims
Methods
