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

The influence of implant factors on patient outcomes in primary total knee arthroplasty

Background

The influence of implant factors on patient-reported outcome measures (PROMS) after total knee arthroplasty (TKA) has previously been studied but findings are often inconsistent, restricted in scope and biased by confounding factors. This study aims to determine the association between implant-related factors and early post-operative PROMs after TKA.

Methods

Using data from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) PROMs program, the study included 9487 primary TKA procedures performed in 43 hospitals from July 31, 2018 to December 31, 2020. Data included baseline demographic data, surgical details and PROMs collected pre- and 6 months post-operatively. Seven prosthesis characteristics were incorporated in the multivariable model, with proportional odds ordinal regression analysis used to assess their effects on post-operative Oxford knee score (OKS) and joint pain. Adjustments were made for pre-operative OKS and joint pain, as well as potential patient confounders.

Results

At six months, fixed bearing implants showed higher odds of better OKS compared to mobile bearing implants (odds ratio [OR] = 1.20, 95 % confidence interval [CI] 1.06-1.37. p < 0.004). Similar findings were found with the use of image derived instrumentation (IDI) (OR = 1.27, 95 % CI 1.11-1.46, p < 0.001), robotic assisted vs. non-navigated knees (OR = 1.21, 95 % CI 1.06-1.38, p < 0.005) and no patella resurfacing (OR = 1.10, 95 % CI 1.01-1.20, p < 0.032). For lower pain scores at six months, the use of highly crosslinked polyethylene (OR = 1.12, 95 % CI 1.02-1.22, p < 0.015), cemented femoral components (OR = 1.11, 95 % CI 1.01-1.22, p < 0.024), IDI (OR = 1.20, 95 % CI 1.05-1.37, p < 0.009) or no patella resurfacing (OR = 1.10, 95 % CI 1.01-1.20, p < 0.034) were associated.

Conclusion

Utilizing a fixed bearing or robotic assistance correlated with improved OKS scores, whereas highly crosslinked polyethylene or cemented femoral components were associated with improved pain scores. At six months, the use of IDI compared to non-navigated TKA, and patellar resurfacing showed both improved OKS and pain scores.

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

BACKGROUND

Secondary 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.

METHODS

The 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).

RESULTS

An 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%.

CONCLUSIONS

An 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.

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

PURPOSE

The 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.

METHODS

A 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.

RESULTS

A 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.

CONCLUSION

Comparison 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.

The AAHKS Clinical Research Award: Resurfacing the Thin Native Patella: Is It Safe?

BACKGROUND

Whether to resurface the patella during total knee arthroplasty (TKA) remains debated. One often cited reason for not resurfacing is inadequate patellar thickness. The aim of this study was to describe the implant survivorships, reoperations, complications and clinical outcomes in patients who underwent patellar resurfacing of a thin native patella.

METHODS

From 2000 to 2010, 7,477 patients underwent primary TKA with patellar resurfacing and had an intraoperatively, caliper-measured patella thickness at our institution. Of these, 200 (2.7%) had a preresection patellar thickness of ≤19 millimeters (mm). Mean preresection thickness was 18 mm (range, 12-19). Mean age was 69 years, mean body mass index was 31 kg/m², and 93% of the patients were women. Median follow-up was 10 years (range, 2-20).

RESULTS

At 10 years, survivorships free of any patella revision, patella-related reoperation, and periprosthetic patella fracture were 98%, 98%, and 99%, respectively. There were 3 patella revisions (1 aseptic loosening, 2 periprosthetic joint infections). There were 2 additional patella-related reoperations for patellar clunk. There were 3 nonoperatively managed periprosthetic patella fractures. Radiographically, all nonrevised knees had well-fixed patellae. Knee society scores improved from mean 36 points (interquartile range [IQR] 24-49) preoperatively to mean 81 points (IQR 77-81) at 10-year follow-up.

CONCLUSION

Resurfacing the thin native patella was associated with high survivorship free of patellar revision at 10-year follow-up. Nevertheless, there was 1 case of patellar loosening and 3 periprosthetic patella fractures. These risks must be weighed against the known higher incidence of revision when the thin native patella is left unresurfaced.

Patellar Resurfacing in Total Knee Arthroplasty, a Never-Ending Controversy; Case Report and Literature Review

Total knee arthroplasty (TKA) remains a lifesaving procedure for advanced gonarthrosis. However, patella resurfacing (PR) in TKA remains a controversial procedure, leading to extensive discussions amongst orthopedic surgeons, regarding its indications and results. Based on these premises, we present a clinical case of a 70-year-old Caucasian woman admitted for pain, swelling and limitation of left knee joint mobility. Her medical history records an Ahlback stage IV gonarthrosis with simultaneous bilateral TKA surgery performed in different hospital, when two NexGen cemented total prostheses were implanted with patellar resurfacing being performed only on the right side. Our clinical (American Knee Society Score, Lonner and Feller scales) and radiological evaluations (CT scan and Xray) revealed left patellar arthrosis and a slight lateral subluxation of the patella. The chosen treatment plan was revision surgery for PR and patellar prosthesis with a cemented patellar component, cross-linked polyethylene, no 32 NexGen model with 8.5 mm thickness. The immediate and distant postoperative evolution was favorable. Extensive literature review shows that, at present, PR remains at surgeon's discretion mainly based on his previous results. Therefore, we believe there is an imperative need to develop high quality studies based on accurate scientific evidence to universally establish valid guidelines for PR in TKA.

Does Choice of Patellar Implant in Total Knee Arthroplasty Matter?: A Randomized Comparative Trial of 3 Commonly Used Designs

BACKGROUND

There is currently a lack of evidence to identify the optimal patellar implant design in total knee arthroplasty (TKA). The aim of this study was to assess clinical, intraoperative, radiographic, and scintigraphic differences between inlay (IN), onlay round (OR), and onlay oval (OO) patellar implants.

METHODS

A parallel-group, double-blinded, randomized trial compared IN, OR, and OO patellar implants using the same posterior-stabilized TKA prosthesis for each. Patient outcomes were prospectively followed for a minimum of 2 years, with survivorship outcomes followed for a mean of 5 years. The primary outcome was the between-group differences in the mean Kujala score change from preoperatively to 2 years postoperatively. The secondary outcomes included differences in other knee-specific and general health outcomes, intraoperative characteristics, radiographic parameters, patellar vascularity, and implant survivorship.

RESULTS

A total of 121 participants (40 in the IN group, 41 in OR group, 40 in the OO group) were allocated to 1 of 3 implant designs. At 2 years postoperatively, there were no significant differences in Kujala score changes between groups (p = 0.7; Kruskal-Wallis test). Compared with the IN group, the OR group showed greater improvements in Knee injury and Osteoarthritis Outcome Score (KOOS) Activities of Daily Living and in KOOS Quality of Life compared with the OO group. However, the OO design exhibited better bone coverage and lower lateral facetectomy rates compared with the IN and OR designs. The IN group had more lateral contact compared with the OO group (p = 0.02; Fisher exact test), but the overall value for lateral contact was not significant (p = 0.09; chi-square test). There were no differences in postoperative scintigraphic vascularity (p = 0.8; chi-square test). There was 1 revision for infection at 3 years postoperatively in the OO group, and no revision in the other groups.

CONCLUSIONS

Patellar design did not influence patellofemoral outcomes or survivorship. However, OR implants showed improvements in some secondary patient-reported outcome measures, and OO implants exhibited superior bone coverage and improvements in several intraoperative, radiographic, and scintigraphic outcomes. These findings, combined with superior long-term implant survivorship from previous studies, add support for the use of onlay designs in TKA.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Higher use of fixed-bearing over mobile-bearing and posterior-stabilized over medial pivot designs in total knee arthroplasty (TKA): a systematic comparative analysis using worldwide arthroplasty registers from England and Wales, Australia, Norway, New Zealand, Germany and Switzerland

INTRODUCTION

The aim of this study was to compare the use of mobile-bearing, fixed-bearing, posterior-stabilized (PS) and medial pivot design to describe epidemiological differences and subsequent outcomes.

MATERIALS AND METHODS

A systematic literature search was performed using the NORE website to identify the relevant arthroplasty registers. Inclusion criteria were the following: (1) reports had to be publicly available, (2) reports had to be written in German or English language, (3) differentiation between mobile- and fixed-bearing, posterior-stabilized, and if possible, medial pivot designs had to be possible from the present reports, and (4) data had to be reported for at least three consecutive years and the latest report had to be from the year 2020 to retrieve recent data.

RESULTS

Six registries (England and Wales, Australia, Norway, New Zealand, Germany, Switzerland) offered sufficient data according to the inclusion criteria. In all countries, the dominant type of bearing used for total knee arthroplasty (TKA) was fixed-bearing, with percentages ranging from 60.8% to 84.1% in 2018, 63.6% to 85.7% in 2019 and 66.2% to 87.4% in 2020. A large variation was observed concerning mobile-bearing design, which showed a range from 2.8% to 39.2% in 2018, 2.6% to 36.4% in 2019 and 2.9% to 33.8% in 2020. Some variation was found regarding the use of PS TKA, as its percentage frequency ranged from 9.7% to 29.2% in 2018, 9.8% to 29.4% in 2019 and 10.1% to 28.5% in 2020. Medial pivot design had a share of 9.1% in 2018, 8.6% in 2019 and 8.4% in 2020 in Australia, while it only accounted for 1.4% in 2018, 2.1% in 2019 and 2.5% in 2020 in Germany.

CONCLUSION

The comparison of arthroplasty registers from England and Wales, Australia, Norway, New Zealand, Germany and Switzerland revealed large differences regarding the application of posterior-stabilized designs, but also common ground considering the overwhelming use of fixed-bearing inserts, which, when inserted correctly, eradicate the potential complication of bearing dislocation. Arthroplasty registers offer a real-world clinical perspective with the aim to improve quality and patient safety.

Application and Surgical Technique of ACL Reconstruction Using Worldwide Registry Datasets: What Can We Extract?

Anterior cruciate ligament (ACL) injuries are among the most common knee injuries. The purpose of this study was to compare surgical reconstruction of the ACL between different countries and regions in order to describe differences regarding epidemiological data, reconstruction frequency, and graft choice. A systematic literature search was performed using the ACL study group website in order to identify the relevant knee ligament registers. Four national registries were included, comprising those from Sweden, the UK, New Zealand, and Norway. A large variation was found concerning the total number of primary ACL reconstructions with a reported range from 4.1 to 51.3 per 100,000 inhabitants. The country-specific delay between injury and reconstruction varied between an average of 6.0 months and 17.6 months. The leading sports activities resulting in ACL injury included soccer, alpine skiing, handball, rugby, and netball. Moreover, a strong variability in graft choice for primary reconstruction was found. The comparison of ACL registers revealed large differences, indicating different clinical implications regarding conservative or surgical therapy and choice of the preferable graft. ACL registers offer a real-world clinical perspective with the aim to improve quality and patient safety by investigating factors associated with subsequent surgical outcomes.

Controversy: supporting patellar resurfacing in total knee arthroplasty - do it

Patellar resurfacing during total knee arthroplasty remains a controversial topic.Some surgeons routinely resurface the patella to avoid the increased rates of postoperative anterior knee pain and reoperation for secondary resurfacing, whilst others selectively resurface based on the presence of preoperative anterior knee pain, damaged articular cartilage, inflammatory arthritis, isolated patellofemoral arthritis, and patellar subluxation and/or maltracking. A third group of surgeons never resurface the patella.The anatomy and biomechanics of the patellofemoral joint as well as the advances in surgical techniques and prosthetic design must be taken into account when making a decision about whether to resurface the patella. Accurate component implantation if the patella is resurfaced becomes crucial to avoid complications.In our institution before 2008 we were performing a selective resurfacing of the patella, but in the last decade we have decided to always resurface it, with good outcomes and low complication rate. A reproducible surgical technique may be helpful in reducing the risk of postoperative anterior knee pain and complications related to implants.In this article we analyse the current trend and controversial topics in dealing with the patella in total knee arthroplasty, and discuss the available literature in order to sustain our choice. Cite this article: EFORT Open Rev 2020;5:785-792. DOI: 10.1302/2058-5241.5.190075.

A systematic review of pain outcomes reported by randomised trials of hip and knee arthroplasty

It is difficult to pool results from randomised clinical trials that report different outcomes. We want to develop a core set of pain-related outcomes after total hip or knee arthroplasty, the first stage of which is to systematically review published outcomes. We searched PubMed, Embase and CENTRAL for relevant trials to January 2020. We identified 165 outcomes from 565 trials with 50,668 participants, which we categorised into six domains: pain; analgesic consumption; quality of care; adverse events; mobility; and patient-reported outcome measures. The outcome in each domain reported by most trials was: visual analogue score for pain, 401 (71%); morphine consumption, 212 (38%); length of hospital stay, 166 (29%); nausea or vomiting, 425 (75%); range of motion, 173 (31%); and patient satisfaction score, 181 (32%). A primary outcome was reported in 281 (50%) trials: 101 (18%) trials reported consumption of rescue analgesics and 95 (17%) trials reported pain. We plan to publish a consensus on outcomes that should be reported in postoperative pain trials after hip or knee arthroplasty.

Survival Rate and Application Number of Total Hip Arthroplasty in Patients With Femoral Neck Fracture: An Analysis of Clinical Studies and National Arthroplasty Registers

BACKGROUND

Total hip arthroplasty (THA) is an increasingly popular treatment option for fractured neck of femur (NOF). The primary aim of this study is to systematically review all literature on primary THA and hemiarthroplasty (HA) after fractured NOF to calculate an overall revision rate. Furthermore, we wanted to compare primary THA implantations after fractured NOF between different countries in terms of THA number per inhabitant.

METHODS

All clinical studies on THA and HA for femoral neck fractures between 1999 and 2019 were reviewed and evaluated with a special interest on revision rate. Revision rate was calculated as "revision per 100 component years." THA registers were compared between different countries with respect to the number of primary implantations per inhabitant.

RESULTS

THA studies showed a mean revision rate of 11.8% after 10 years, which was lower than a 24.6% 10-year revision rate for HA. We identified 8 arthroplasty registers that revealed an annual average incidence of THA for fractured NOF of 9.7 per 100,000 inhabitants.

CONCLUSION

This study showed that patients with THA were less likely to be revised at 10 years compared to HA. We found similar annual numbers of THAs for fractured NOF per inhabitant across countries. The results of this analysis can be used to rank present and future national THA numbers within an international context.

The Effect of Surgeon Preference for Selective Patellar Resurfacing on Revision Risk in Total Knee Replacement: An Instrumental Variable Analysis of 136,116 Procedures from the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

The optimum strategy regarding resurfacing the patella in total knee replacement (TKR) remains debated, with wide national and international variability. To minimize the confounders of a direct comparison of cases with or without resurfacing, we performed an instrumental variable analysis examining revision risk on the basis of surgeon preference for patellar resurfacing in TKR, specifically examining the subsequent patellar revision risk and all-cause revision risk among cases of surgeons preferring to perform resurfacing on a selective basis compared with those whose preference is to routinely resurface or who infrequently perform resurfacing.

METHODS

Data from the Australian Orthopaedic Association National Joint Replacement Registry from 1999 to 2016 were obtained to assess the cumulative percent revision, hazard ratio, and revision diagnoses for 3 cohorts, grouped according the surgeons' patellar-resurfacing preferences: infrequently (<10% of the time), selectively (10% to <90% of the time), or routinely (≥90% of the time). To avoid confounding from implant design or surgeon performance, only minimally stabilized TKRs using hybrid or cemented fixation and performed by surgeons performing ≥50 TKR procedures per year were included.

RESULTS

A total of 136,116 procedures were included, with patients in all 3 cohorts having similar demographics. The selectively resurfaced cohort had a higher patellar revision risk compared with the routinely resurfaced cohort, with this risk being greatest in the first 4.5 years following the primary procedure, including 306% higher in the first 1.5 years, and remaining 50% higher after 4.5 years. In a subgroup analysis, increased revision risk was observed among males, females, those <65 years of age, and those ≥65 years of age. The infrequently resurfaced cohort had the highest risk of subsequent patellar revision, up to 482% higher, as seen in the first 1.5 years after the primary procedure, compared with the routinely resurfaced cohort. Additionally, the risk of all-cause revision was 20% higher for the selectively resurfaced cohort compared with routinely resurfaced.

CONCLUSIONS

Surgeons who preferred selective resurfacing of the patella had a higher risk of patellar revision than those who had preference for routine resurfacing of the patella. Overall, a greater preference for resurfacing resulted in a lower risk of patellar revision.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Arthroplasty implant registries over the past five decades: Development, current, and future impact

Local, regional, and national registries have played an important role in the development of hip and knee arthroplasty and the treatment of patients with various maladies of these joints. Four arthroplasty registries stand out as leading forces behind the drive to popularize the use of registries and pursue the concept of evidence based medicine. The Mayo registry, started by Mark Coventry, is recognized as the oldest continuing registry for arthroplasty. The Harris Registry at Massachusetts General Hospital, along with the Mayo Registry, has greatly contributed to the advancement of arthroplasty surgery and have served an important role of identifying poorly performing implants and techniques in the United States. The Swedish Knee Arthroplasty Registry is the oldest national registry dedicated to joint arthroplasty and along with the Swedish Hip Arthroplasty Registry have established the infrastructure, analysis and reporting mechanisms, and leadership that has enabled other countries to subsequently develop national registries around the world. As more countries have adopted the concept of national registries, a new area of research is possible by pooling the resources of large registries as is now occurring with the Nordic countries. Several international organizations have been formed to promote future collaboration and develop international standards. The process of globalization of registries is a result of continued efforts over the past 50 years in improving and disseminating the knowledge gained from the early registries. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2319-2330, 2018.

Trends and Economic Impact of Hip and Knee Arthroplasty in Central Europe: Findings from the Austrian National Database

Arthroplasty registers were originally established in Scandinavia to receive clinically relevant information from pooled data, to improve quality and reduce revision surgeries, with socioeconomic benefit. In Austria, where the highest rate of total knee arthroplasties (TKA) per inhabitant of all OECD countries was reached in 2014, arthroplasties are centrally reported since 2009. Study purpose was to perform the first analysis of the Austrian database, aiming to obtain data on trends in arthroplasty in Austria over time in relation to demographic development. Between 2009 and 2015 an almost continuous increase of total hip arthroplasties (THA; 18.052) by 14% and TKA (17.324) by 13% were observed, representing 210 THA and 202 TKA per 100k inhabitants in 2015. A similar increase was found for revision surgeries, with 1.290 re-implanted THA (7.1% of all THA) and 919 re-implanted TKA (5.3% of all TKA) in 2015. Implantation of mega or tumor prosthesis for the knee and hip joint remained constant and was mainly performed in two university hospitals. Patellar resurfacing decreased by 31.6%. Demographic development will further increase the number of primary and revision surgeries. Inclusion of more detailed information on used and revised components was established and will improve efficacy in quality control.

Registry Data-Valuable Lessons But Beware the Confounders

A mature national joint registry with widespread adoption and audit can successfully demonstrate trends and influence future orthopedic practice. Correlations can be identified; however, this should not be misinterpreted as causality. It is essential to consider confounding when analyzing observational datasets.

[Anesthetic requirements measured by bilateral bispectral analysis and femoral blockade in total knee arthroplasty]

BACKGROUND AND OBJECTIVES

A continuous peripheral nerve blockade has proved benefits on reducing postoperative morphine consumption; the combination of a femoral blockade and general anesthesia on reducing intraoperative anesthetic requirements has not been studied. The objective of this study was to determine the relevance of timing in the performance of femoral block to intraoperative anesthetic requirements during general anesthesia for total knee arthroplasty.

METHODS

A single-center, prospective cohort study on patients scheduled for total knee arthroplasty, were sequentially allocated to receive 20mL of 2% mepivacaine throughout a femoral catheter, prior to anesthesia induction (Preoperative) or when skin closure started (Postoperative). An algorithm based on bispectral values guided intraoperative anesthetic management. Postoperative analgesia was done with an elastomeric pump of levobupivacaine 0.125% connected to the femoral catheter and complemented with morphine patient control analgesia for 48hours. The Kruskall Wallis and the chi-square tests were used to compare variables. Statistical significance was set at p<0.05.

RESULTS

There were 94 patients, 47 preoperative and 47 postoperative. Lower fentanyl and sevoflurane were needed intraoperatively in the Preoperative group; median values and range: 250 (100-600) vs 450 (200-600)μg and 21 (12-48) vs 32 (18-67)mL p=0.001, respectively. There were no differences in the median verbal numeric rating scale values 4 (0-10) vs 3 (0-10); and in median morphine consumption 9 (2-73) vs 8 (0-63)mg postoperatively.

CONCLUSIONS

A preoperative femoral blockade is useful in decreasing anesthetic requirements in total knee arthroplasty surgery but no added effect in the postoperative analgesic control.

Is Selectively Not Resurfacing the Patella an Acceptable Practice in Primary Total Knee Arthroplasty?

BACKGROUND

To resurface or not to resurface the patella remains a controversy in total knee arthroplasty (TKA). The purpose of this study was to assess the long-term outcomes associated with selectively not resurfacing the patella.

METHODS

This was a historical cohort study of 15,497 patients with 21,371 primary TKA procedures performed at a single institution between 1985 and 2010. The cohort included 402 (2%) knees with unresurfaced patellae and 20,969 knees with all-polyethylene patellae designs. Reasons for not resurfacing the patella were documented. Multivariable Cox regression analyses were used to estimate the risk of complications and revisions among procedures with unresurfaced patellae.

RESULTS

According to the surgeon, reasons for not resurfacing were normal cartilage (226, 56%), young patient (30, 8%), thin patella (53, 13%), and surgeons' choice (93, 23%). In age, sex, and calendar year-adjusted analyses, the risk of complications (hazard ratio [HR]: 1.25, 95% confidence interval [CI]: 1.06, 1.46) and all-cause revisions (HR: 1.39, 95% CI: 1.02, 1.89) were significantly higher after TKA with unresurfaced patellae. However, after adjusting for femoral component types and operative diagnoses, these associations were no longer significant. The only group with significantly worse outcomes were those with a thin patellae with increased risk of complications (HR: 2.66, 95% CI: 1.70, 4.17) and revisions (HR: 5.94, 95% CI: 2.35, 15.02). Yet, the excess risk in the thin patellae group was mainly due to infections, and not related to unresurfaced patellae.

CONCLUSION

Selectively not resurfacing the patella seemed to provide similar results compared with routine resurfacing.

Impact of preoperative antithrombotic therapy on blood management after implantation of primary total knee arthroplasty

Red blood cell concentrates (RCC) substitution after total knee arthroplasty (TKA) is correlated with multifold of complications and an independent predictor for higher postoperative mortality. TKA is mainly performed in elderly patients with pre-existing polymorbidity, often requiring permanent preoperative antithrombotic therapy (PAT). The aim of this retrospective analysis was to investigate the impact of demand for PAT on inpatient blood management in patients undergoing TKA. In this study 200 patients were retrospectively evaluated after TKA for differences between PAT and non-PAT regarding demographic parameters, preoperative ASA score > 2, duration of operation, pre-, and intraoperative hemoglobin level, and postoperative parameters including amount of wound drainage, RCC requirement, and inpatient time. In a multivariate logistic regression analysis the independent influences of PAT, demographic parameters, ASA score > 2, and duration of the operation on RCC demand following TKA were analyzed. Patients with PAT were significantly older, more often had an ASA > 2 at surgery, needed a higher number of RCCs units and more frequently and had lower perioperative hemoglobin levels. Multivariate logistic regression revealed PAT was an independent predictor for RCC requirement. PAT patients are more likely to require RCC following TKA and should be accurately monitored with respect to postoperative blood loss.

Buprenorphine added to bupivacaine prolongs femoral nerve block duration and improves analgesia in patients undergoing primary total knee arthroplasty-a randomised prospective double-blind study

The aim of the study was to determine whether the addition the long-acting opioid buprenorphine as an adjuvant to the local anaesthetic agent would improve quality and prolong duration of femoral nerve blockade in post-operative analgesia following primary total knee arthroplasty. The study involved 48 patients. The femoral nerve was anaesthetised with a 0.25% solution of bupivacaine with adrenaline or with the addition of 0.3mg of buprenorphine. The duration of the sensory block and analgesic effect was assessed according to NRS scale at 12, 24, 36, 48, 60 and 72 hours post-surgery. Patients who received buprenorphine as an adjuvant to the local anaesthetic had significantly longer sensory blockade and lower NRS-rated pain intensity with the difference reaching statistical significance at 12 hours post-surgery.

Knee osteoarthritis and role for surgical intervention: lessons learned from randomized clinical trials and population-based cohorts

PURPOSE OF REVIEW

Over the last decade, there has been increased recognition of the importance of high-quality randomized controlled trials in determining the role of surgery for knee osteoarthritis. This review highlights key findings from the best available studies, and considers whether or not this knowledge has resulted in better evidence-based care.

RECENT FINDINGS

Use of arthroscopy to treat knee osteoarthritis has not declined despite strong evidence-based recommendations that do not sanction its use. A large randomized controlled trial has demonstrated that arthroscopic partial meniscectomy followed by a standardized physical therapy program results in similar improvements in pain and function at 6 and 12 months in comparison to physical therapy alone in patients with knee osteoarthritis and a symptomatic meniscal tear, confirming the findings of two previous trials. Two recent randomized controlled trials have demonstrated that decision aids help people to reach better-informed decisions about total knee arthroplasty. A majority of studies have indicated that for people with obesity the positive results of total knee arthroplasty may be compromised by postoperative complications, particularly infection.

SUMMARY

More efforts are needed to overcome significant evidence-practice gaps in the surgical management of knee osteoarthritis, particularly arthroscopy. Decision aids are a promising tool.

Gender-specific outcome after implantation of low-contact-stress mobile-bearing total knee arthroplasty with a minimum follow-up of ten years

PURPOSE

The study aim was an analysis of gender-specific outcome differences after implantation of the low-contact-stress (LCS) mobile-bearing total knee arthroplasty (TKA) with a minimum follow-up of ten years.

METHODS

We retrospectively analysed 138 prostheses in 108 patients (82 women and 26 men) using our hospital database and a minimum follow-up of ten years (mean 14, range 11-23). Data was extracted with respect to quality of life, clinical outcome parameters [range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, visual analogue scale (VAS), Knee Society Score (KSS), and complications.

RESULTS

At follow-up, we observed no statistically significant differences in all outcome parameters between female and male patients after LCS TKA, except for VAS score, which revealed no clinical relevance due to the low difference (1.53 vs 1.03, p = 0.043).

CONCLUSIONS

Ten years after implantation of the LCS TKA, gender did not influence its beneficial outcome.

The patella in total knee arthroplasty: to resurface or not is the question

The decision to resurface the patella during total knee arthroplasty remains controversial. Even though some surgeons routinely resurface the patella to avoid the increased rates of postoperative anterior knee pain and reoperation for secondary resurfacing, others selectively resurface based on the presence of anterior knee pain, notably damaged articular cartilage, inflammatory arthritis, isolated patellofemoral arthritis, and patellar subluxation and maltracking. The anatomy and biomechanics of the patellofemoral joint, combined with advances in surgical technique and prostheses must be taken into account when making a decision to resurface the patella. Accurate component implantation is imperative for a successful outcome if the patella is resurfaced.

Pre-operative autologous blood donation versus no blood donation in total knee arthroplasty: a prospective randomised trial

PURPOSE

During total knee arthroplasty (TKA) blood loss can be significant and in spite of all techniques for reducing blood loss there is still a significant possibility for blood transfusions. For blood loss management during TKA, pre-operative autologous blood donation (PABD) is still a standard of care. In this prospective randomised study we have evaluated the efficacy of PABD in patients undergoing TKA to answer the question whether there is any need for autologous blood donations during TKA and, if yes, for which group of patients.

METHODS

Patients were randomised to three groups. In group 1 patients did not donate autologous blood, in group 2 patients donated 1 dose 72 hours prior to TKA and in group 3 patients donated autologous blood 14 days prior to TKA. In all patients haemoglobin, haematocrit, thrombocyte and reticulocyte values, iron concentrations (Fe, unsaturated iron binding capacity, total iron binding capacity), activated partial thromboplastin time, prothrombin time, and intra-operative and post-operative blood loss were measured and compared.

RESULTS

With PABD there was no reduction in allogeneic blood transfusions and a large number of taken doses of autologous blood was discarded, which significantly increased the cost of treatment for these patients. For patients undergoing TKA, PABD can provoke iatrogenic anaemia and thereby increase the likelihood of the need for allogeneic blood transfusion.

CONCLUSIONS

Results of our study showed that PABD in non-anaemic patients is not justified and is not economically feasible.