Robotic-arm assisted total knee arthroplasty is associated with improved accuracy and patient reported outcomes: a systematic review and meta-analysis.

This systematic review and meta-analysis were conducted to compare the accuracy of component positioning, alignment and balancing techniques employed, patient-reported outcomes, and complications of robotic-arm assisted total knee arthroplasty (RATKA) with manual TKA (mTKA) and the associated learning curve. Searches of PubMed, Medline and Google Scholar were performed in October 2020 using PRISMA guidelines. Search terms included "robotic", "knee" and "arthroplasty". The criteria for inclusion were published clinical research articles reporting the learning curve for RATKA and those comparing the component position accuracy, alignment and balancing techniques, functional outcomes, or complications with mTKA. There were 198 articles identified, following full text screening, 16 studies satisfied the inclusion criteria and reported the learning curve of rTKA (n=5), component positioning accuracy (n=6), alignment and balancing techniques (n=7), functional outcomes (n=7), or complications (n=5). Two studies reported the learning curve using CUSUM analysis to establish an inflexion point for proficiency which ranged from 7 to 11 cases and there was no learning curve for component positioning accuracy. The meta-analysis showed a significantly lower difference between planned component position and implanted component position, and the spread was narrower for RATKA compared with the mTKA group (Femur coronal: mean 1.31, 95% confidence interval (CI) 1.08-1.55, p<0.00001; Tibia coronal: mean 1.56, 95% CI 1.32-1.81, p<0.00001). Three studies reported using different alignment and balancing techniques between mTKA and RATKA, two studies used the same for both group and two studies did not state the methods used in their RATKA groups. RATKA resulted in better Knee Society Score compared to mTKA in the short-to-mid-term follow up (95%CI [- 1.23, - 0.51], p=0.004). There was no difference in arthrofibrosis, superficial and deep infection, wound dehiscence, or overall complication rates. RATKA demonstrated improved accuracy of component positioning and patient-reported outcomes. The learning curve of RATKA for operating time was between 7 and 11 cases. Future well-powered studies on RATKAs should report on the knee alignment and balancing techniques utilised to enable better comparisons on which techniques maximise patient outcomes.Level of evidence III.

Revision of Unicompartmental to Total Knee Arthroplasty: Does the Unicompartmental Implant (Metal-Backed vs All-Polyethylene) Impact the Total Knee Arthroplasty?

BACKGROUND: The aim of this study is to investigate differences in implant requirement, outcomes, and re-revision when total knee arthroplasty (TKA) was performed following unicompartmental knee arthroplasties (UKAs) with metal-backed (MB) compared to all-polyethylene (AP) tibial components. METHODS: Retrospective study of 60 UKAs converted to 60 TKAs at mean 7.3 years (0.1 to 17) after implantation in 55 patients (mean age, 64 [49-83]; 44% male): 44 MB and 16 AP. TKA implant requirement was investigated in addition to mode of failure, Oxford Knee Score, and TKA survival at mean 5.4 years (0.5 to 17). RESULTS: Progression of osteoarthritis was the commonest mode of failure in MB UKAs (P = .03) and unexplained pain in AP (P = .011) where revisions were performed earlier (4.8 ± 3.2 vs 8.2 ± 4.5, P = .012). In 56 of 60 (93%) cases, unconstrained TKA implants were used. The use of standard cruciate-retaining TKAs without augments or stems was less likely following MB UKA compared to AP (12 of 38 [32%] vs 10/14 [71%], P = .013). Specifically MB UKA implants were associated with more tibial stem use (P = .04) and more use of cruciate-substituting polyethylene (P = .05). There was no difference in the use of constrained implants. Multivariate analysis showed tibial resection depth to predict stem requirement. Seven were re-revised giving 7-year TKA survival: from MB UKA 70.3 (95% CI, 47.0 to 93.6) and from AP UKA 87.5 (95% CI, 64.6 to 100; P = .191). CONCLUSION: MB UKA implants increase the chances of a complex revision requiring tibial stems and cruciate substitution but reduce the chances of early revision compared to AP UKA which often fail early with pain.

Aseptic Revision Knee Arthroplasty With Total Stabilizer Prostheses Achieves Similar Functional Outcomes to Primary Total Knee Arthroplasty at 2 Years: A Longitudinal Cohort Study.

BACKGROUND: Patient function is poorly characterized following revision total knee arthroplasty (TKA), although is generally accepted to be inferior to that following primary procedures. METHODS: Fifty-three consecutive aseptic revisions to total stabilizer devices were prospectively evaluated, preoperatively and at 6, 26, 52, and 104 weeks postoperatively, using the Oxford Knee Score (OKS), range of motion, pain rating scale, and timed functional performance battery. Data were assessed longitudinally and in comparison to primary TKA data with identical outcome assessments at equivalent time points. RESULTS: Mean outcome changes were: 13 point increase in the OKS (from 17.5 [standard deviation-SD 7.4]-32.4 [SD 7.9] points); 21 degree improvement in the knee flexion (80.6 [SD 20.5]-101.5 [SD 13.2] degrees); 60% reduction in the pain report (7.7 [SD 2.3]-1.3 [SD 0.4] points); and 15 second improvement in the timed performance assessment (47.2 [SD 19.1]-32.0 [SD 7.0] seconds; P < .001). No difference was seen between primary and revision cohorts in OKS or pain scores (analysis of variance, P = .2 and .19). Knee flexion and timed performance assessment were different between primary and revision groups (analysis of variance, P = .03 and P = .02); however, this was due to differing preoperative values. The revision cohort achieved the same postoperative scores as the primary cohort at all postoperative time points. CONCLUSION: Patients undergoing revision TKA for aseptic failure with total stabilizer implants made substantial improvements in the initial 2 years following surgery in both patient-reported and directly assessed function, comparable with that achieved following primary knee arthroplasty.

Complications related to therapeutic anticoagulation in total hip arthroplasty.

Bleeding-related wound complications cause significant morbidity in lower limb arthroplasty surgery. Patients who require therapeutic anticoagulation in the perioperative period are potentially at higher risk for these complications. This is a retrospective case-control study reviewing all primary total hip arthroplasties performed in a single center during a 5-year period and comparing outcomes of the patients on warfarin with a double-matched control group of patients not on warfarin. The warfarin group had a significantly higher risk of deep joint infection (9% vs 2.2%), hematoma/wound ooze (28% vs 4%), and superficial infection (13.5% vs 2.2%). Managing patients undergoing total hip arthroplasty with therapeutic anticoagulation is a balance between the risk of thromboembolic disease and bleeding-related complications. Improved understanding of this risk will better allow patients to make an informed decision regarding their elective arthroplasty surgery.

Early muscle recovery following robotic-assisted unicompartmental knee arthroplasty.

BACKGROUND: Robotic-assisted unicompartmental knee arthroplasty (UKA) improves implant accuracy, however whether this translates to patient function is less clear. Various outcomes have been reported but muscle recovery has not been previously investigated. OBJECTIVE: To explore sequential change in lower limb muscle strength following robotic-assisted UKA with isokinetic dynamometry. RESULTS: 12 participants undergoing rUKA for medial compartment osteoarthritis were assessed pre-operatively, and at 6- and 12-weeks post-operatively. Maximal muscle strength changed over time in both quadriceps (p = 0.006) and hamstrings (p = 0.018) muscle groups. Quadriceps strength reduced from 88.52(39.86)Nm to 74.47(27.58)Nm by 6-weeks (p = 0.026), and then recovered to 90.41(38.76)Nm by 12-weeks (p = 0.018). Hamstring strength reduced from 62.45(23.18)Nm to 54.12(20.49)Nm by 6-weeks (p = 0.016), and then recovered to 55.07(17.99)Nm by 12-weeks (p = 0.028). By 12-weeks quadriceps strength was 70% and hamstrings 83% of the values achieved in the un-operated limb. Substantial improvement was seen in all other measures over time, with sequential positive change in Timed-up-and-go test (p = 0.015), 10 m walk test (p = 0.021), range of knee flexion (p = 0.016) and PROMs (p < 0.025).

Scaling digital radiographs for templating in total hip arthroplasty using conventional acetate templates independent of calibration markers.

We describe a scaling method for templating digital radiographs using conventional acetate templates independent of template magnification without the need for a calibration marker. The mean magnification factor for the radiology department was determined (119.8%; range, 117%-123.4%). This fixed magnification factor was used to scale the radiographs by the method described. Thirty-two femoral heads on postoperative total hip arthroplasty radiographs were then measured and compared with the actual size. The mean absolute accuracy was within 0.5% of actual head size (range, 0%-3%) with a mean absolute difference of 0.16 mm (range, 0-1 mm; SD, 0.26 mm). Intraclass correlation coefficient showed excellent reliability for both interobserver and intraobserver measurements with intraclass correlation coefficient scores of 0.993 (95% CI, 0.988-0.996) for interobserver measurements and intraobserver measurements ranging between 0.990 and 0.993 (95% CI, 0.980-0.997).

Robotic arm-assisted versus manual total hip arthroplasty : a systematic review and meta-analysis.

AIMS: The aims of this systematic review were to assess the learning curve of semi-active robotic arm-assisted total hip arthroplasty (rTHA), and to compare the accuracy, patient-reported functional outcomes, complications, and survivorship between rTHA and manual total hip arthroplasty (mTHA). METHODS: Searches of PubMed, Medline, and Google Scholar were performed in April 2020 in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Search terms included "robotic", "hip", and "arthroplasty". The criteria for inclusion were published clinical research articles reporting the learning curve for rTHA (robotic arm-assisted only) and those comparing the implantation accuracy, functional outcomes, survivorship, or complications with mTHA. RESULTS: There were 501 articles initially identified from databases and references. Following full text screening, 17 articles that satisfied the inclusion criteria were included. Four studies reported the learning curve of rTHA, 13 studies reported on implant positioning, five on functional outcomes, ten on complications, and four on survivorship. The meta-analysis showed a significantly greater number of cases of acetabular component placement in the safe zone compared with the mTHA group (95% confidence interval (CI) 4.10 to 7.94; p < 0.001) and that rTHA resulted in a significantly better Harris Hip Score compared to mTHA in the short- to mid-term follow-up (95% CI 0.46 to 5.64; p = 0.020). However, there was no difference in infection rates, dislocation rates, overall complication rates, and survival rates at short-term follow-up. CONCLUSION: The learning curve of rTHA was between 12 and 35 cases, which was dependent on the assessment goal, such as operating time, accuracy, and team working. Robotic arm-assisted total hip arthroplasty was associated with improved accuracy of component positioning and functional outcome, however no difference in complication rates or survival were observed at short- to mid-term follow-up. Overall, there remains an absence of high-quality level I evidence and cost analysis comparing rTHA and mTHA. Cite this article: Bone Joint J 2021;103-B(6):1009-1020.

In vitro comparison of Refobacin-Palacos R with Refobacin Bone Cement and Palacos R + G.

BACKGROUND: Refobacin Palacos R (RPR) is no longer produced and Palacos R + G (PRG) and Refobacin Bone Cement R (RBC) have been introduced to supersede it. We performed an in vitro study to ascertain whether the handling and mechanical properties of the more recent cement preparations are different to those of their predecessor. METHODS: The 3 cements were tested to ISO 5833 and German DIN 53435 standards. In addition, their gentamicin elution, shrinkage, viscosity, and handling characteristics were studied. RESULTS: All 3 cements had comparable mechanical properties exceeding the ISO 5833 and DIN 53435 standards. They eluted similar amounts of gentamicin and had comparable shrinkage. In the batches tested, RBC showed statistically significantly longer handling curves. Both PRG and RBC had statistically significantly lower viscosities as they cured compared to their predecessor. INTERPRETATION: Surgeons must be aware that both successor cements do not appear to have handling curves and viscoelastic properties identical to those of RPR.

Inter- and intra-batch variability in the handling characteristics and viscosity of commonly used antibiotic-loaded bone cements.

BACKGROUND: Several factors can affect the viscosity of a cement and therefore its handling characteristics. We performed an in vitro study to ascertain whether anecdotal observations of differences in handling between batches of the same brand of cement actually existed. METHODS: 3 batches of Simplex P Tobramycin (SPT), Refobacin Bone Cement (RBC), SmartSet GHV (SSG) and Palacos R+G (PRG) were tested. 6 replicates of each batch were vacuum-mixed and their viscosity in relation to time was measured under laboratory conditions using a rheometer. We examined the handling characteristics of 6 replicates of each batch after they were hand-mixed under theater conditions. RESULTS: Inter- and intra-batch variability was seen in the viscosity of all brands of cement tested. Interbatch calculations were influenced by high intra-batch variability in viscosity. The viscosity of RBC cement was similar to that of SSG, but different to that of PRG (p = 0.01 at 5 N and p = 0.009 at 40 N). INTERPRETATION: Our results suggest that in clinical practice, extrinsic factors such as preparation conditions and methods probably play a more important role than the intrinsic variability of cements. However, variability in handling and viscosity will exist in all brands of cement prepared under theater conditions and the surgeon must be aware of why they may act differently.

Ewing's Sarcoma of the Upper Extremity: Presenting Symptoms, Diagnostic Delay and Outcome.

PURPOSE: To look at the presenting features, Enneking stage, size of primary tumour, method of treatment and patient and doctor delays in upper extremity Ewing's sarcoma to observe the effects on local recurrence, metastasis and survival. PATIENTS AND METHODS: Nineteen patients with upper extremity Ewing's sarcoma were identified using the Scottish Bone Tumour Registry over the past 40 years. RESULTS: With increasing tumour Enneking stage at presentation there was a significantly higher mortality (P=0.02). Patients with a higher Enneking stage also had an increased trend towards local recurrence (P=0.08). Stage did not influence the occurrence of metastasis. Patients with larger tumours tended to have a higher mortality (50 vs. 27% dead at 5 years). All patients presented clinically with pain and all but two complained of some sort of swelling. There was a trend towards a higher Enneking Stage in patients presenting with a longer duration of symptoms (P=0.1). No difference in survival was noted between patients undergoing surgery and chemotherapy and patients undergoing radiotherapy and chemotherapy. Disease-free survival was 100% at both 5 and 10 years for Enneking stage IIA, 56% at 5 and 10 years for stage IIB and 0% at 5 years for stage III. DISCUSSION: This study re-emphasises the potential importance of a diagnostic delay on outcome. Longer symptom duration is associated with a higher Enneking stage at presentation. In turn a higher presenting stage results in a higher mortality. Pain and swelling are prominent clinical findings at first presentation in upper extremity Ewing's.