Patellar Resurfacing Research Articles

RISK OF REVISION FOLLOWING TOTAL HIP AND KNEE ARTHROPLASTY PERFORMED USING COMPUTER-ASSISTED TECHNOLOGIES VERSUS CONVENTIONAL TECHNIQUE: AN ANALYSIS OF NATIONAL JOINT REGISTRY DATA

AbstractIntroductionComponent mal-positioning in total hip replacement (THR) and total knee replacement (TKR) can increase the risk of revision for various reasons. Compared to conventional surgery, relatively improved accuracy of implant positioning can be achieved using computer assisted technologies including navigation, patient-specific jigs, and robotic systems. However, it is not known whether application of these technologies has improved prosthesis survival in the real-world. This study aimed to compare risk of revision for all-causes following primary THR and TKR, and revision for dislocation following primary THR performed using computer assisted technologies compared to conventional technique.MethodsWe performed an observational study using National Joint Registry data. All adult patients undergoing primary THR and TKR for osteoarthritis between 01/04/2003 to 31/12/2020 were eligible. Patients who received metal-on-metal bearing THR were excluded. We generated propensity score weights, using Sturmer weight trimming, based on: age, gender, ASA grade, side, operation funding, year of surgery, approach, and fixation. Specific additional variables included position and bearing for THR and patellar resurfacing for TKR. For THR, effective sample sizes and duration of follow up for conventional versus computer-guided and robotic-assisted analyses were 9,379 and 10,600 procedures, and approximately 18 and 4 years, respectively. For TKR, effective sample sizes and durations of follow up for conventional versus computer-guided, patient-specific jigs, and robotic-assisted groups were 92,579 procedures over 18 years, 11,665 procedures over 8 years, and 644 procedures over 3 years, respectively. Outcomes were assessed using Kaplan-Meier analysis and expressed using hazard ratios (HR) and 95% confidence intervals (CI).ResultsFor THR, analysis comparing computer-guided versus conventional technique demonstrated HR of 0.771 (95%CI 0.573–1.036) p=0.085, and 0.594 (95%CI 0.297–1.190) p=0.142, for revision for all-causes and dislocation, respectively. When comparing robotic-assisted versus conventional technique, HR for revision for all-causes was 0.480 (95%CI 0.067 –3.452) p=0.466. For TKR, compared to conventional surgery, HR for all-cause revision for procedures performed using computer guidance and patient-specific jigs were 0.967 (95% CI 0.888–1.052) p=0.430, and 0.937 (95% CI 0.708–1.241) p=0.65, respectively. HR for analysis comparing robotic-assisted versus conventional technique was 2.0940 (0.2423, 18.0995) p = 0.50.ConclusionsThis is the largest study investigating this topic utilising propensity score analysis methods. We did not find a statistically significant difference in revision for all-causes and dislocation although these analyses are underpowered to detect smaller differences in effect size between groups. Additional comparison for revision for dislocation between robotic-assisted versus conventionally performed THR was not performed as this is a subset of revision for all-causes and wide confidence intervals were already observed for that analysis. It is also important to mention this NJR analysis study is of an observational study design which has inherent limitations. Nonetheless, this is the most feasible study design to answer this research question requiring use of a large data set due to revision being a rare outcome.Declaration of Interest(b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

FUNCTIONAL OUTCOME OF TOTAL KNEE REPLACEMENT WITH AND WITHOUT PATELLAR RESURFACING

FUNCTIONAL OUTCOME OF TOTAL KNEE REPLACEMENT WITH AND WITHOUT PATELLAR RESURFACING

REASONS FOR TOTAL KNEE ARTHROPLASTY REVISIONS: A RETROSPECTIVE COHORT STUDY

The aim of this retrospective cohort study was to investigate the reasons for total knee arthroplasty (TKA) revisions at a tertiary hospital over a four-year period. The study aimed to identify the primary causes of TKA revisions and shed light on the implications for patient care and outcomes.The study included 31 patients who underwent revisions after primary knee arthroplasty between January 2017 and December 2020. A retrospective approach was employed, utilizing medical records and radiological findings to identify the reasons for TKA revisions. The study excluded oncology patients to focus on non-oncologic indications for revision surgeries. Patient demographics, including age and gender, were recorded. Data analysis involved categorizing the reasons for revision based on clinical assessments and radiological evidence.Among the 31 patients included in the study, 9 were males and 22 were females. The age of the patients ranged from 43 to 81, with a median age of 65 and an interquartile range of 18.5. The primary reasons for TKA revisions were identified as aseptic loosening (10 cases) and prosthetic joint infection (PJI) (13 cases). Additional reasons included revision from surgitech hemicap (1 case), patella osteoarthritis (1 case), stiffness (2 cases), patella maltracking (2 cases), periprosthetic fracture (1 case), and patella resurfacing (1 case). The findings of this retrospective cohort study highlight aseptic loosening and PJI as the leading causes of TKA revisions in the examined patient population.These results emphasize the importance of optimizing surgical techniques, implant selection, and infection control measures to reduce the incidence of TKA revisions. Future research efforts should focus on preventive strategies to enhance patient outcomes and mitigate the need for revision surgeries in TKA procedures.

Cementless and Cemented Total Knee Arthroplasties Have Similar Outcomes but Cementless Patellar Component Migration was Observed in a Paired Randomized Control Trial

BackgroundCementless total knee arthroplasty (TKA) has become increasingly popular. Some surgeons are concerned about pain, implant stability, and metal-backed patellar component survivorship. This study investigated the outcomes of cementless compared with cemented TKA in bilateral cases. MethodsWe randomized 80 knees in 40 osteoarthritic knee patients who underwent bilateral TKA with patellar resurfacing under one anesthesia. All participants received cementless prostheses in one knee and cemented prostheses in the other. The outcomes were knee function measured by the forgotten joint scores, modified Western Ontario and McMaster Universities Osteoarthritis Index, knee ranges of motion, pain levels, operative times, radiographic outcomes, and complications. All knees were followed for a minimum of 2 years (2 to 3 years). ResultsCementless and cemented TKA had similar functional outcomes in forgotten joint score (97 ± 5 versus 98 ± 3 points, P = .52), modified Western Ontario and McMaster Universities Osteoarthritis Index score (3 ± 4 versus 3 ± 2 points, P = .96), and ranges of motion (134 ± 7° versus 134 ± 7°, P = .16). The postoperative pain was also similar (P > .05). There were 4 cementless patellar components had superior migration for an average of 3.5 mm (range, 1.77 to 4.16) without loosening. The mean time of migration was 4 (range, 2 to 6) weeks. ConclusionsCementless TKA had similar functional outcomes and recovery patterns compared with cemented TKA. However, there was concern of cementless component migration at patellae.

What are the Outcomes of Secondary Patella Resurfacing for Dissatisfaction Following Primary Knee Arthroplasty? A Systematic Review and Meta-Analysis of 604 Knees

BackgroundSecondary patella resurfacing is often performed for dissatisfaction following primary knee arthroplasty where the native patella was retained. The purpose of this meta-analysis was to evaluate outcomes of secondary patella resurfacing. MethodsThe systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies reporting on patients who underwent secondary patella resurfacing after previous primary knee arthroplasty with retention of the native patella were considered eligible. The risk of bias was assessed using the Methodological Index for Non-Randomized studies tool. A random-effects model and the inverse-variance weighting method was used for meta-analysis. There were sixteen retrospective studies including 604 knees (594 patients) with a mean follow up of 42 months (range, 2 to 197). ResultsAn overall improvement in patient-reported outcomes (PROMs) was achieved in 53% of cases from pooled data available for 293 knees [95% Confidence Interval (CI) (0.44, 0.62), I2=68% - moderate heterogeneity]. The pooled proportion of patients satisfied with the procedure was 59% [95% CI (48, 68), I2 = 70% - moderate heterogeneity] in a sample size of 415. There was a minimal rate (2%) of complication incidence when performing secondary patella resurfacing and a pooled rate of revision surgery of 10%. ConclusionsAn improvement in pain, satisfaction, and PROMs was achieved in slightly more than half of the patients following secondary patella resurfacing. However, studies lacked standardized objective selection criteria for the procedure and the available data was predominantly retrospective, with high heterogeneity and variation in outcome reporting.

The effect of femoral prosthesis design on patellofemoral contact stresses in total knee arthroplasty: a case–control study with mid-term follow-up minimum 3-year follow-up

BackgroundTo investigate the differences in postoperative patellofemoral pressures and patellar tracking during at least three years of follow-up in patients using three prostheses of different designs in total knee arthroplasty (TKA) without patellar resurfacing.Methods: Radiographic investigationsThe study included 401 patients who had a total of 480 knee prostheses implanted without patellar resurfacing. The prostheses used were Genesis II (external rotation design of femoral prosthesis), Triathlon (design with deep trochlear grooves), and Gemini MK II (deepening of trochlear groove and lateral condylar protrusion that closely follows the anatomical shape). The patients' patellar tracking was assessed by measuring patellar tilt and displacement during postoperative follow-up. Furthermore, postoperative knee function and pain were evaluated through range of motion, Knee Society scores (KSS), and Forgotten Joint Score (FJS) to compare the different groups.Finite element analysisConstructing a finite element model of the knee joint of a normal volunteer after total knee arthroplasty using different prostheses for nonpatellar replacement. The three models' von Mises stress distribution heat map, peak contact pressure, and patellar transverse displacement were compared at 30°, 60°, and 90°, respectively.Results: Radiographic investigationsA total of 456 knees of 384 patients were investigated at a 3-year follow-up after TKA without patellar resurfacing. There were no significant differences in patellar tracking between the three groups. Patients with all three prostheses demonstrated favorable clinical outcomes at 3 years postoperatively, with no statistically significant differences in knee scores (91.9 vs 92.3 vs 91.8) or range of motion (127.9° vs 128.5° vs 127.7°) between the groups. However, there was a significant difference between Genesis II and Gemini MK II in the Forgotten Joint Score (59.7 vs 62.4). Patients with persistent postoperative anterior knee pain were present in all three groups (16 vs 12 vs 10), but the incidence was not significantly different.Finite element analysisThe von Mises stress distribution heat map showed that during flexion, the patellofemoral stresses were mainly concentrated on the lateral side of the prosthesis side, and the contact site gradually shifted downward with increasing flexion angle. At the same time, the peak contact stress of the patellofemoral joint increased with the gradual increase in the flexion angle. Genesis II, with a wider and shallower trochlear groove, showed greater patellofemoral stresses and lateral patellar displacement after TKA without patellar resurfacing. The Gemini MK II with a deeper trochlear groove and slightly protruding lateral condyle is more in line with anatomical design, with smaller patellofemoral joint pressure and better patellar tracking.ConclusionsIn TKA without patellar resurfacing, a prosthesis with a deeper trochlear groove, a slightly higher lateral femoral condyle, and a more anatomically designed knee that better matches the patellar morphology should be a better choice.

Development of application and surgical technique of total knee arthroplasties: a systematic comparative analysis using worldwide registers

PurposeThe aim was to compare total knee arthroplasty (TKA) between countries with regard to epidemiologic data and surgical technique by the use of worldwide registers and compare findings with a previous report after one decade.MethodsA systematic search was carried out in November 2022 and compared to previous reports from 2010. We extracted data regarding implanted TKAs, patients’ age distribution, procedure types, fixation and revision rates. After identification of 28 national arthroplasty registers, 8of them, namely Australia, Canada, Denmark, England and Wales, New Zealand, Norway, Scotland and Sweden, offered sufficient data and were included in final analysis.ResultsA large variation was found in the annual number of implantations per 100,000 inhabitants with a range from 77 to 210.2 (mean 132.8). The fixation type varied strongly as well, e.g. over 95% of totally cemented TKAs in Sweden versus 61.2% cemented fixation in Denmark. Another significant difference was the use of patellar resurfacing in TKA, ranging from 47.3% (Canada) using a patellar button in TKA to less than 5% (Sweden). Within the period of one decade, the mean overall number of annual implantations increased (10%), whilst relative number of revisions decreased, the use of cemented TKA decreased from 87 to 74%, and the use of patella button remained largely inhomogeneous.ConclusionComparison of arthroplasty registers revealed large differences regarding the annual number of primary TKAs per inhabitant as well as primary TKA procedure types with an increase of annual implantations, decrease of relative number of revisions, and a decrease of the use of cemented systems over the period of one decade.

Knee

The October 2023 Knee Roundup360 looks at: Cementless total knee arthroplasty is associated with more revisions within a year; Kinematically and mechanically aligned total knee arthroplasties: long-term follow-up; Aspirin thromboprophylaxis following primary total knee arthroplasty is associated with a lower rate of early periprosthetic joint infection compared with other agents; The impact of a revision arthroplasty network on patient outcomes; Re-revision knee arthroplasty in a tertiary centre: how does infection impact on outcomes?; Does the knee joint have its own microbiome?; Revision knee surgery provision in Scotland; Aspirin is a safe and effective thromboembolic prophylaxis after total knee arthroplasty: a systematic review and meta-analysis; Patellar resurfacing and kneeling ability after total knee arthroplasty: a systematic review.

Predictors of Undergoing Revision Within 5 Years of Total Knee Arthroplasty: A Population-Based Study

BackgroundThe objective of this study was to identify the rate and risk factors for revision total knee arthroplasty (TKA) within the first 5 years postoperative. Our secondary objective was to identify the rate of additional surgical procedures and death. MethodsWe conducted a retrospective cohort study among patients in Ontario, Canada who underwent an elective, primary TKA between April 1, 2007, and March 31, 2014, for osteoarthritis. We excluded patients under 40 years and who had undergone a TKA within the previous 15 years. Our final study cohort included 94,193 patients. We reported the proportion of the study cohort who experienced revision surgery within 2 and 5 years of the primary TKA; secondary surgery within 5 years. We conducted Cochran-Armitage tests for trends to assess changes in the proportion of patients who experienced each of the study outcomes, and multivariable logistic regressions to evaluate predictors of a revision TKA. ResultsThere were 3,112 (3.3%) patients who had a revision within 5 years, and 1,866 (2.0%) within 2 years of their primary TKA. 3,316 (3.5%) had a secondary surgery (0.6% patellar resurfacing; 1.6% manipulation; 1.3% synovectomy; 0.5% washout; 0.9% debridement). Lower age, men, lower income, higher comorbidity score, depression, previous arthroscopy, lower surgeon volume, and general anesthesia were all significant positive predictors of revision. ConclusionsIn our study cohort, 2.0% of patients had a revision TKA within 2 years, and 3.3% within 5 years of their primary TKA. Preoperative identification of risk factors may reduce the future prevalence of revision TKAs.

To resurface or not to resurface? Investigating the impact of patellar resurfacing on anterior knee pain in rheumatoid arthritis patients undergoing total knee replacement

BackgroundRoutine patellar resurfacing is a controversial issue in total knee replacement (TKR), especially for rheumatoid arthritis (RA). Anterior knee pain (AKP) is a common complaint after TKR that may be related to patellofemoral joint condition. The aim of this study was to investigate the prevalence and factors associated with AKP after TKR for RA compared between non-resurfaced patella (NRP) and resurfaced patella (RP). MethodsThis retrospective study included RA patients who underwent TKR at our institute from 2002 to 2019. All included patients had at least 1 year of follow up. Patients were divided into the NRP and RP groups. At the last follow up visit, the prevalence of AKP, and the severity of AKP, including visual analogue pain score (VAPS) and Kujala score, were compared between groups. Univariate and multivariate logistic regression analysis was performed to identify independent predictors of AKP. ResultsA total of 141 RA patients (median age: 60 years, 90% female, 219 knees) were included. There was no significant difference in AKP between the NRP and RP groups (12.7% vs. 7.3%, P = 0.185). Regarding AKP severity, there was no significant difference in VAPS or Kujala score between groups (P = 0.147 and P = 0.067, respectively). No independent predictors of AKP were identified. ConclusionAlthough patellar resurfacing is recommended in TKR for RA, this study found no significant difference in prevalence of AKP, VAPS and Kujala score between those with and without patellar resurfacing during TKR.

Current State of Knee Arthroplasty in Russia: Analysis of 36,350 Сases from the Register of the Vreden National Medical Research Center of Traumatology and Orthopedics

Background.Nowadays the knee arthroplasty register of the Vreden National Medical Research Center of Traumatology and Orthopedics (hereinafter referred to as the Vreden Center) contains clinical and statistical data on more than 39,000 primary and revision knee replacements, that mimics current state of this kind of surgery in Russia.
 Aimofthestudy to analyze the last decade trends in primary knee arthroplasty in largest Russian arthroplasty center.
 Methods.Data were obtained from the register of the Vreden Center for the period from 2011 to 2022. Information on knee arthroplasty included epidemiologic and numerous peri-operative data including type of surgery and implant, degree of constrain, primary patella resurfacing etc.
 Resultsanddiscussion.From 2011 to 2022, 36,350 (92.3%) primary arthroplasties performed at the Vreden Center.
 The number of interventions increased more than twice: from 1,678 in 2011 to 3,924 in 2022. Similar trends observed in Australia and Sweden, where the number of knee arthroplasties increased by 8.2% and 8% in 2021 compared to 2020, respectively. The frequency of primary patellar resurfacing at the Vreden Center was 2.2% over the entire period of observation. On the contrary, the rate of patella replacement increased from 41% in 2005 to 76.1% in 2021 in Australia and from 24.4% in 2015 to 31.9% in 2020 in Switzerland. The partial knee arthroplasty showed enormous growth more than 14 times: from 0.3% in 2011 to 4.3% in 2022 at the Vreden Center. Worldwide unicompartmental knee replacement is still less popular than total and its number widely varies: 4.2% in the USA, 6.9% in Australia, 9.2% in Canada, 11.9% in Norway, 12.8% in Sweden, and 18.4% in Switzerland. Posterior cruciate ligament (PCL) retaining total knee arthroplasties (TKA) prevailed at the Vreden Center: 68.3%, while in other countries it utilize even more widely: 70.5% in Norway, 75% in New Zealand and 93.5% in Sweden.
 The total length of hospital stay (LOS) decreased dramatically from 19.6 in 2011 to 8.6 in 2022 at the Vreden Center. Nevertheless, there are still opportunities to improve it: by the way in Canada the average LOS for TKA is 2.3 and the USA 0.8 and 1.7 for partial and total arthroplasty, respectively.
 Conclusion.The main current trends of knee arthroplasty in Russia are the following: increase the number of surgeries, reduced LOS, TKA without patella resurfacing and with PCL retention, finally the growth of partial knee arthroplasties.

Transillumination method in total knee arthroplasty: new approach with old tools

PurposeIn this study, we evaluated the possibility of precise intraoperative localization of the lateral genicular arteries by an orthopaedic surgeon using the transillumination method.MethodsTwelve patients underwent cemented TKA with patella-friendly Zimmer Biomet NexGen Legacy Posterior Stabilized prostheses (without patellar resurfacing), seven right knees and five left knees. The mean age of patients in the study group was 66.636 ± 7.003 years. The minimal follow-up period was 13 months (mean—16.363 ± 2.5 months). Functional outcomes were assessed using Knee Society and a specific patellar questionnaire—Kujala Score. Intraoperative detection of insufficient patellar stability and/or patellar maltracking was based on the no-thumb technique. In pre- and postoperative period X-ray investigation, standard standing X-ray and Merchant view were used to evaluate implant position and patellofemoral congruency.ResultsIn this study, ten out of twelve knee joints (83.3%) had at least one artery visible by the proposed method in the lateral parapatellar area. Five out of ten knee joints had more than one artery that could be visualized and identified as an arterial vessel. Postoperative Knee Society Score showed significant improvement from a mean 51.181 ± 3.868 to a mean 88.727 ± 3.663. Mean hospital length of stay is 8.545 ± 1.863 days. X-ray assessment using standard anteroposterior, lateral, and Merchant skyline views showed appropriate implant positioning and patellofemoral congruency. The mean Kujala Score in the postoperative period (3 and 6 months) was 67.3 ± 6.75 and 75.6 ± 6.42, respectively.ConclusionsUsing the proposed transillumination method can help preserve the lateral blood supply to the patella and to avoid devascularized patella-related complications.Trial registrationRetrospectively registered on 5 of May 2023, Registration number – 3/3-1757.

Preoperative patellar bone marrow lesions with full thickness cartilage defects correlate with residual anterior knee pain in total knee arthroplasty without patellar resurfacing.

Residual anterior knee pain is one of the most common problems after total knee arthroplasty (TKA). However, the contributing factors affecting postoperative anterior knee pain (AKP) remain poorly understood. This study aimed to evaluate the effect of preoperative patellar bone marrow lesions (BMLs) and patellar cartilage defects on postoperative AKP after patellar non-resurfacing TKA. This retrospective study included 336 patients who underwent unilateral TKA without patella resurfacing. All patients underwent preoperative magnetic resonance imaging (MRI) to assess the presence of BMLs and the degree of cartilage defects in the patella. Patients were categorized into four groups according to the presence of BMLs (with or without BMLs) and the degree of cartilage defects (with or without full thickness cartilage defects). The Kujala Anterior Knee Pain Scale (AKPS) and the Hospital for Special Surgery Knee Rating Scale (HSS) scores at 2 years after TKA were compared among the groups. Preoperative BMLs in the patella were found in 132 (39.3%) of 336 cases. Among the four groups, the group with both BMLs and full-thickness cartilage defects demonstrated significantly lower AKPS compared to the other groups at 2 years after TKA (p < 0.01), but no significant difference was shown in the HSS scores, between these groups. There were no significant differences in either AKPS or HSS scores among the other three patient groups. The presence of preoperative BMLs with full-thickness cartilage defects in the patella was associated with worse postoperative AKP after TKA without patella resurfacing. Patella resurfacing should be considered in this patient group to minimize the risk of developing residual AKP after TKA. III.

Relationships between position of patellar ridge high point and morphology of resected surface for patellar resurfacing in total knee arthroplasty.

Reproducing the native patellar ridge high point while maximizing osseous coverage is important for the success of patellar replacement, but it cannot always be achieved simultaneously. This study aimed to thoroughly investigate the relationships and their influencing factors between the positions of the high point of patellar ridge (HPPR) and the morphology of the patellar resected surface. Four hundred seventy-three patients (265 men, 208 women) aged 18 to 50 years with knee injuries before arthroscopy were retrospectively collected for this cross-sectional study. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to construct 3D computer models of the patella and patellar cartilage. The morphometric characteristics of the patellar cut after virtual resection and the HPPR position relative to the patellar cut centre were measured and analyzed. The medial displacements of the HPPR were positively correlated with Wiberg's classification and index (all P<0.001). The mean values of HPPR's medial displacements were 0.15 of the medial width of patellar cut, and 93.2% of all patella ranged from 0 to 0.3. When the implant's apex were placed at 0.15 of the medial width of patellar cut medialized, the proportion of implant placement errors within 1 mm of the native high point was 12% more in female patella (P=0.01), and 7% more in all patella (P=0.03) than 3 mm medialized. Wiberg's system can roughly predicted the medial-lateral position of the HPPR. The HPPR was mainly medially located at the 0.15 of the medial patellar width approximately, and 15% medialized of the implant's apex can better reproduce the native patellar high point than 3 mm medialized. The current results provide basic data for patellar implant selection, preoperative planning, and implant design to reproduce the native patellar high point better while maximizing osseous coverage for patellar resurfacing.

The Effect of Surgeon Volume on Revision for Periprosthetic Joint Infection: An Analysis of 602,919 Primary Total Knee Arthroplasties.

Periprosthetic joint infection (PJI) is a devastating complication of total knee arthroplasty (TKA). An association between low surgeon volume and higher rates of infection following primary TKA has been suggested. The purpose of the present study was to determine if there was a relationship between surgeon volume and the rate of revision for infection after primary TKA. We searched the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to identify all primary TKA procedures that were performed for the treatment of osteoarthritis from September 1, 1999, to December 31, 2020, and were subsequently revised because of infection. Surgeon volume was defined as the annual volume of procedures performed by a surgeon during the same year in which the primary TKA (which was subsequently revised for infection) was performed. Surgeon volume was defined as <25, 25 to 49, 50 to 74, 75 to 99, or ≥100 primary TKA procedures/year. The cumulative percent revision (CPR) for infection was determined with use of Kaplan-Meier estimates. Cox proportional hazards methods were used to compare rates of revision for infection by surgeon volume, with subanalyses for patellar resurfacing and polyethylene use. Further analyses for patients <65 years of age and male patients were undertaken. Overall, 602,919 primary TKA procedures were performed for the treatment of osteoarthritis, of which 5,295 were revised because of infection. High-volume surgeons (≥100 TKAs/year) had a significantly lower rate of revision for infection, with a CPR at 1 and 19 years of 0.4% (95% confidence interval [CI], 0.3 to 0.4) and 1.5% (95% CI, 1.2 to 2.0), respectively, compared with 0.6% (95% CI, 0.5 to 0.7) and 2.1% (95% CI, 1.8 to 2.3), respectively, for low-volume surgeons (<25 TKAs/year). Hazard ratios (HRs), adjusted for age and sex, comparing these 2 groups varied, depending on the time point, between 3.07 (95% CI, 2.02 to 4.68) and 1.44 (95% CI, 1.26 to 1.63) but remained significant (p < 0.001). When the analysis was adjusted for age, sex, American Society of Anesthesiologists (ASA) classification, and body mass index (BMI), there remained an increased risk of revision for PJI for all lower surgeon volume levels in comparison with the high- surgeon-volume group (≥100 TKAs/year). The results were similar when stratified by patellar resurfacing and cross-linked polyethylene (XLPE) and adjusted for age and sex. High-volume surgeons had lower rates of revision for infection. A better understanding of how surgical volume contributes to decreasing this complication is important and requires in-depth study. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Resurfacing Versus Non-resurfacing Patella in Total Knee Replacement: When and What to Choose.

The opinion on the necessity of patella resurfacing has been deeply divided in the scientific community. There are three approaches to the management of the patella in total knee arthroplasty (TKA). The first method involves always resurfacing the patella, the second method involves never resurfacing it, and the third method involves resurfacing the patella only under specific circumstances. Different data support each of these strategies, but no consensus on the best management has been reached. This is a retrospective study of 106 cases of TKA (including 29 resurfaced patellas and 77 non-resurfaced patellas), over 5 years, at the Trauma-Orthopedics Department of theCheikh Khalifa International University Hospital, Mohammed VI University of Health Sciences, Casablanca, Morocco. Our objective is to conduct a comparative study between TKA with patella resurfacing and those without resurfacing, by analyzing the functional and radiological results obtained after the operation, to show each technique's advantages and disadvantages. The average age of our patients was 65 years with extremes ranging from 46 to 80 years. There was a clear female predominance with a sex ratio of 0.2. The left side was predominantly affected. Primary gonarthrosis was the main diagnosis. Our results showed no significant difference between the two groups in terms of patient satisfaction and Knee Society Score (KSS). Nevertheless, complications generated by resurfacing, such as infection, anterior pain, stiffness, and loosening of the patellar component, as well as additional costs and increased operative time, were observed. In the majority of meta-analyses, there was no discernible difference in clinical and functional results between the resurfaced and non-resurfaced groups, suggesting that patellar resurfacing is not beneficial and, therefore, unnecessary. It appears that regular resurfacing is not necessary. However, there is agreement that resurfacing the patella is the best course of action for patients with inflammatory arthropathy, considerable patella malalignment, and severe patellofemoral osteoarthritis. There are arguments in favor of each of the patella resurfacing techniques, but none of them are particularly compelling, each of these strategies has itsadvantages and should not be considered bad. The final decision, therefore, rests on each surgeon's practice, training, and experience.

PATELLA RESURFACING DOES NOT IMPROVE OUTCOMES IN PATIENTS WITH POSTOPERATIVE FLEXION CONTRACTURE AFTER PRIMARY TOTAL KNEE ARTHROPLASTY

Objective: Biomechanical studies have shown that flexion contracture leads to higher patellofemoral compressive forces with potentially poorer outcomes. We studied the outcome of primary knee arthroplasty with or without patella resurfacing in patients presenting with postoperative flexion contracture to determine if patella resurfacing improves the outcome. Materials and Methods: We retrospectively reviewed the registry data at the Singapore General Hospital from 1998-2014. Of 18074 primary knee replacements carried out, 665 knees were identified with postoperative flexion contracture greater than 10 degrees at 2 years follow-ups, out of which 562 knees were included in the study. One hundred and three patients were lost to follow-ups. All the infected cases were excluded from the study. Knees with patella resurfaced (227) were compared with knees with patella non-resurfaced (335) using Oxford Knee Score, Knee Society Clinical Scoring System, and SF-36. A handheld goniometer was used for measurements by an independent assessor and a physiotherapist. Analysis of factors for prognostic importance was performed using the R statistics. Results: At two years follow-ups, the non-resurfaced patella group had significantly higher median knee flexion compared to the resurfaced group. Age, male gender, preoperative flexion, and patella resurfacing were found to be significant predictors for knee flexion at two years. Outcome scores did not differ significantly between the two groups. Conclusion: No significant difference in outcome scores was observed in resurfaced versus non-resurfaced patella groups in patients with more than 10 degrees’ postoperative flexion contracture after primary knee arthroplasty. Keywords: Patella Resurfacing, Flexion contracture

Low readmission and reattendance rate in day-case total knee arthroplasties.

The rate of day-case total knee arthroplasty (TKA) in the UK is currently approximately 0.5%. Reducing length of stay allows orthopaedic providers to improve efficiency, increase operative throughput, and tackle the rising demand for joint arthroplasty surgery and the COVID-19-related backlog. Here, we report safe delivery of day-case TKA in an NHS trust via inpatient wards with no additional resources. Day-case TKAs, defined as patients discharged on the same calendar day as surgery, were retrospectively reviewed with a minimum follow-up of six months. Analysis of hospital and primary care records was performed to determine readmission and reattendance rates. Telephone interviews were conducted to determine patient satisfaction. Since 2016, 301/7350 TKAs (4.1%) in 290 patients at our institution were discharged on the day of surgery. Mean follow-up was 31.4 months (6.2 to 70.0). In all, 28 patients (9.3%) attended the emergency department or other acute care settings within 90 days of surgery, most often with wound concerns or leg swelling; six patients (2.0%) were readmitted. No patients underwent a subsequent revision procedure, and there were no periprosthetic infections. Two patients (0.7%) underwent secondary patella resurfacing, and one patient underwent arthroscopic arthrolysis after previous manipulation under anaesthetic (MUA). Three patients (1.0%) underwent MUA alone. Primary care consultation records, available for 206 patients, showed 16 patients (7.8%) contacted their general practitioner within two weeks postoperatively; two (1.0%) were referred to secondary care. Overall, 115/121 patients (95%) telephoned stated they would have day-case TKA again. Day-case TKA can be safely delivered in the NHS with no additional resources. We found low incidence of contact with primary and secondary care in the postoperative period, and high patient satisfaction.

Surgical treatment of knee osteoarthritis focusing on the patellofemoral joint

Background: Surgical management of the osteoarthritic knee joint consists of osteotomies such as a high tibial osteotomy (HTO), uni-compartmental knee arthroplasty (UKA), and total knee arthroplasty (TKA). These surgeries mainly treat the tibiofemoral joint but can also have an impact on the patellofemoral (PF) joint. These changes in PF joint can affect the surgical outcome.Current Concepts: PF joint problems are relative contraindications in UKA. However, recent studies have reported that these problems do not markedly affect the result of UKA. During HTO, the patella height and tracking can change, affecting the PF joint problem. The effect of the PF joint can be minimized through various methods of closing wedge HTO or modified opening wedge (OW) HTO, such as retro-tubercular biplanar OWHTO. However, this method is controversial regarding its impact on clinical outcomes. In TKA, pain caused by PF joint problems can be reduced using techniques such as patella resurfacing, patelloplasty, and denervation; however, there is no clear consensus.Discussion and Conclusion: The surgical treatment of degenerative knee osteoarthritis has an impact on the PF joint, which can affect the outcome of surgery and vice versa. However, these impacts only occasionally cause clinical difference. Conclusively, these surgeries should be done by considering the PF joint because changes in the joint can affect the surgical outcome.

LONG-TERM SURVIVAL RATES ARE SIMILAR WITH OR WITHOUT PATELLAR RESURFACING AFTER TOTAL KNEE ARTHROPLASTY, HOWEVER, HIGHER REVISION RATE WITHOUT PATELLAR RESURFACING CAN BE PROSTHETIC-SPECIFIC: A NATIONAL JOINT REGISTRY ANALYSIS

AbstractIntroductionThe role of patellar resurfacing in total knee arthroplasty remains controversial. We questioned the effect of patellar resurfacing on the early and late revision rates after total knee arthroplasty.Materials and MethodsWe analysed the data of cumulative revisions of primary knee replacement from the NJR 19th Annual Report. NJR included secondary patellar resurfacing as a revision. We compared differences in the 3-year and 15-year revision rates between the patellar resurfacing and non-resurfacing for the different combinations of total knee replacements using a paired t-test. We performed subgroup analysis for the five combinations with the highest volumes.ResultsTwenty-seven implant combinations had the 15-year revision rates reported. Patellar resurfacing group had lower mean 3-year revision rate of 1.68 (SD 0.7) compared to 2.02 (SD 0.9) in non-resurfacing group (p=0.05). However, 15-year revision rate was similar between the two groups (mean 5.7, SD 2.1 vs. mean 5.7, SD 2.2; p = 0.46).High volume implants showed that two combinations (NexGen CR and PS) had similar revision rates at 3 and 15 years between resurfacing and non-resurfacing groups. Three combinations (PFC Sigma CR and PS and Genesis 2 CR) had higher revision rate in non-resurfacing group at 3 years (p=0.01) and the difference persisted at 15 years (p=0.05).ConclusionsAlthough revision rate in total knee arthroplasty was higher without patellar resurfacing at 3 years, at 15 years the difference was not significant. However, the higher revision without patellar resurfacing can be prosthetic combination specific which surgeons need to be aware of.