Younger age is associated with a higher risk of early periprosthetic joint infection and aseptic mechanical failure after total knee arthroplasty

Methodological Assessment of the 100 Most-Cited Articles in Total Knee Arthroplasty in the Last Decade Compared to the All-Time List

BACKGROUND

Recent advances in total knee arthroplasty (TKA) have been driven by a growing focus on evidence-based medicine. This transition is reflected in the critical appraisal of both, the quality of work and the potential impact on the orthopedic community. The purpose of our study was to (1) identify the top 100 most-cited articles in TKA in the last decade and from all-time, and (2) compare methodological rigor of the most-cited articles in TKA in the last decade to articles all-time by level of evidence.

METHODS

The top 100 cited articles were recorded for manuscripts from the last decade, January 1, 2012 to December 31, 2022, and manuscripts from all-time for TKA. We collected authors, year of publication, journal of the article, country of origin of authors, article type (basic science article, clinical research article), level of evidence, methodological index for non-randomized studies score, physiotherapy evidence database scale, and citation density (total citations/years published).

RESULTS

The largest number of studies for all-time TKA (53.0%) and decade TKA (42.0%) were Level III. The average methodological index for non-randomized studies score for comparative studies was 18.7 for all-time TKA and 20.7 for decade TKA (P < .001). The average physiotherapy evidence database score was 6.1 for all-time TKA and 8.1 for decade TKA (P > .05). The highest citation density for all-time TKA was 111 and for past decade was 63. The number of level II studies in TKA increased from 19.0% from all time to 38.0% from the last decade (P < .05).

CONCLUSIONS

Our findings of improved methodologies over time reflect positive steps toward evidence-based practice in TKA. A continued focus on producing methodologically sound studies may guide evidence-based clinical decision-making.

Predictors of reoperation and survival experience for primary total knee arthroplasty in young patients with degenerative and inflammatory arthritis

INTRODUCTION

While total knee arthroplasty (TKA) is typically implemented in patients > 65 years old, young patients may need to undergo TKA for pain relief and functional improvement. Current data are limited by older cohorts and short-term survival rates. This study aimed to examine a large sample size of patients with degenerative and inflammatory conditions who underwent primary TKA at a young (≤ 40) age to identify predictors of reoperation, as well 15-year survivorship.

MATERIALS AND METHODS

A retrospective study was performed on 77 patients (92 surgeries) who underwent primary TKA at ≤ 40 years old, between January 1990 and January 2020. Patient charts were reviewed and a multivariable logistic regression model identified independent predictors of reoperation. Kaplan-Meier analysis was employed to build survival curves and log-rank tests analyzed survival between groups.

RESULTS

Of the 77 patients, the median age at the time of surgery was 35.7 years (IQR: 31.2-38.7) and median follow-up time was 6.88 years. Twenty-one (22.8%) primary TKAs underwent 24 reoperations, most commonly due to stiffness (n = 9, 32.1%) and infection (n = 13, 46.4%) more significantly in the OA group (p = 0.049). There were no independent predictors of reoperation in multivariable analysis, and 15-year revision-free survivorship after TKA did not differ by indication (77.3% for OA/PTOA vs. 96.7% for autoimmune, p = 0.09) or between ≤ 30 and 31-40 year age groups (94.7% vs. 83.6%, p = 0.55).

CONCLUSIONS

In this cohort of patients ≤ 40 years old, revision-free survival was comparable to that reported in the literature for older TKA patients with osteoarthritis/autoimmune conditions (81-94% at 15-years). Though nearly a quarter of TKAs required reoperation and causes of secondary surgery differed between degenerative and inflammatory arthritis patients, there were no significant predictors of increased reoperation rate. Very young patients ≤ 30 years old did not have an increased risk of revision compared to those aged 31-40 years.

Effect of body mass index on acute postoperative complications following Total Ankle Arthroplasty (TAA)

BACKGROUND

Total ankle arthroplasty (TAA) is an effective treatment for various ankle pathologies, but some concern remains for the high associated complication and failure rates relative to major joint arthroplasty of the hip and knee. Patient body mass index (BMI) is a modifiable and potentially important preoperative variable when evaluating postoperative complications. The purpose of this study is to evaluate the effect of BMI, age and sex on the acute postoperative complication rate after TAA.

METHODS

We retrospectively reviewed adult patients who underwent TAA between 2006 and 2021 from the NSQIP database. Using overweight patients as the reference BMI group, we utilized log-binomial models to estimate risk ratios on outcomes while adjusting for sex and age to investigate whether there were significant adjusted differences in complication rates among the BMI groups.

RESULTS

We found that, relative to overweight patients, there were no statistically significant differences in the risk of acute complications for underweight (BMI < 18.5) (P = .118), healthy weight (18.5≤BMI < 25) (P = .544), obese (30≤BMI < 40) (P = .930), or morbidly obese (BMI < 40) (P = .602) patients who underwent TAA. There were also no statistically significant differences in the risk of acute complications based on age category (P = .482,.824) or sex (P = .440) for TAA. Additionally, there were no significant differences between the BMI groups for either major complications (P = .980) or minor complications (P = .168).

CONCLUSION

Ultimately, we found that BMI, age, and sex did not lead to statistically significant differences in the risk of complications within 30 days postoperatively for TAA, even when stratified by major vs minor complications.

LEVEL OF EVIDENCE

Level III.

Outcomes After Total Ankle Arthroplasty in Patients Aged ≤50 Years at Midterm Follow-up

BACKGROUND

Ankle arthritis differs from arthritis of the hip and knee in that 80% is posttraumatic and thus often occurs in a younger patient population. The literature supporting total ankle arthroplasty (TAA) in younger patients has increased over recent years and has bolstered the argument that in the short term, TAA in younger patients has successful outcomes that are comparable to older, lower-demand patients.The purpose of our study was to evaluate patient-reported outcomes (PROs) and implant survivorship at midterm after primary TAA in patients ≤ 50 years of age at the time of surgery.

METHODS

A retrospective chart review was conducted of patients ≤ 50 years of age who underwent primary TAA at a single institution from 2000 to 2017. Patient demographics, outcome measures, and complications were recorded. All patients had a minimum clinical follow-up of 5 years. PRO measures were evaluated at preoperative, 1-year postoperative, and final follow-up visits. Paired t tests were performed to compare individual patient changes in PROs from preoperative. Implant survivorship was evaluated based on need for revision of either the tibial or talar component. The need for additional surgery related to the TAA was also evaluated.

RESULTS

A total of 58 patients were included. The average age at the time of the index surgery was 43.3 years (range 22-50 years). All patients had a minimum follow-up of 5 years with a mean follow-up of 8.8 years. A total of 11 patients required additional surgery related to their TAA. Six patients (10.3%) required bone grafting of peri-implant cysts, 3 patients (5.2 %) required gutter debridement, and 1 patient underwent complete revision of metal components. Mean visual analog scale, 36-item Short Form Health Survey, Short Musculoskeletal Function Assessment, and American Orthopaedic Foot & Ankle Society hindfoot scores significantly improved from preoperative to 1-year postoperative and final postoperative follow-up.

CONCLUSION

The patients aged ≤50 years treated with a TAA whom we have been able to observe for a minimum of 5 years showed generally maintained improvement in functional scores and thus far have had a relatively low rate of secondary surgeries.Level of Evidence:Level III, retrospective cohort study.

High survivorship rate and good clinical outcomes after high tibial osteotomy in patients with radiological advanced medial knee osteoarthritis: a systematic review

INTRODUCTION

The role of valgus producing high tibial osteotomy (HTO) for the treatment of advanced knee osteoarthritis (OA) is still controversial. The aim of the current systematic review was to assess survivorship and patient-reported outcomes (PROMs) of high tibial osteotomy in patients with radiological advanced medial knee OA.

METHODS

A systematic search of PubMed, Cochrane and EMBASE database was performed in July 2023 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines. Inclusion and exclusion criteria were applied to identify studies investigating the survivorship rate and PROMs of valgus-producing high tibial osteotomy in patients with advanced knee OA at x-ray assessment in the medial compartment at minimum-two-years follow up. Advanced radiological OA was defined as Kellgren Lawrence (K-L) ≥ 3 or Ahlbäch ≥ 2. Survivorship was defined as percentage of patients free of total knee arthroplasty (TKA) at follow-up. Clinical interpretation of provided PROMs were performed according to minimal clinically important difference (MCID) and patient acceptable symptom state (PASS) target values reported in literature. Survivorship data and PROMs scores were extracted, and studies were stratified based on selected study features. The quality of included studies was assessed with modified Coleman score.

RESULTS

A total of 18 studies, totalling 1296 knees with a mean age between 46.9 and 67 years old, were included. Average survivorship was of 74.6% (range 60 - 98.1%) at 10-years follow up. The subjective scoring systems showed good results according to MCID and PASS, and postoperative improvements were partially maintained until final follow-up.

CONCLUSION

HTO is worth considering as treatment choice even in patients affected by radiological advanced medial knee osteoarthritis. Long term survivorship and good patient reported clinical outcomes could be expected in this population.

LEVEL OF EVIDENCE

IV; systematic review of level III-IV studies.

Results of a Highly Porous Metal-Backed Cementless Patella Implant: A Minimum 5-Year Follow-Up

Initial design cementless metal-backed patellar implants failed due to multiple reasons including implant design, use of first-generation polyethylene, and surgical technique. This study evaluates clinical outcomes and survivorship of total knee arthroplasty (TKA) using a current generation highly porous metal-backed patellar component. One-hundred twenty-five consecutive primary cementless TKAs with a compression molded highly porous metal-backed patella were reviewed. One-hundred three TKAs (82.4%) with 5-year clinical and radiographic follow-up were available for review. These were matched with 103 consecutive TKAs using a cemented patella of the same implant design. The cementless cohort had a mean age of 65.5 years, body mass index (BMI) of 33.0, and follow-up of 64.4 months. Indications for cementless TKA were based on multiple factors including age, BMI, and bone quality. There were no revisions for loosening or mechanical failure of the cementless patella compared with two cemented patellae revised for aseptic loosening. Eight patients required revisions in the cementless cohort: three for prosthetic joint infection (PJI), two for instability, one periprosthetic femur fracture, one for patella instability, and one for extensor mechanism rupture. Five patients required revisions in the cemented cohort: two for aseptic patellar loosening, one for aseptic femoral loosening, one for PJI, and one for instability. All-cause survivorship at 5 years was 92.2 and 95.1% for the cementless metal-backed implant and cemented implant cohorts, respectively. Use of a compression molded highly porous metal-backed patella component demonstrated excellent clinical and radiographic results at 5-year follow-up. Longer follow-up is required to evaluate the ability of highly porous cementless patella implants to provide durable long-term fixation.

The Current Epidemiology of Revision Total Knee Arthroplasty in the United States From 2016 to 2022

BACKGROUND

The number of revision total knee arthroplasties (TKAs) is projected to reach 268,200 cases annually by 2030 in the United States. The growing demand for revision TKA can be attributed to the successes of primary TKAs combined with an aging population, patient desires to remain active, as well as expanded indications for younger patients. Given the evolving nature of revision TKAs, an epidemiological analysis of: (1) etiologies; (2) demographics, including age and region; as well as (3) lengths of stay (LOS) offers a way to minimize the gap between appropriate understanding and effective intervention.

METHODS

From 2016 to 2022, a national, all-payer database was queried. Incidences and indications were analyzed for a total of 135,983 patients who had revision TKA procedures.

RESULTS

The most common etiologies for revision TKA procedures were infection (19.3%) and aseptic loosening (12.8%), followed by mechanical complications (7.9%). The largest age group was 65 to 74 years (34.9%) followed by 55 to 64 years (32.2%), then age >75 years (20.5%). The South had the largest total procedure cohort (39.8%), followed by the Midwest (28.6%), then the Northeast (18.6%), and the West (13.0%). The mean length of stay was 3.86 days (range, 1.0 to 15.0).

CONCLUSIONS

Our study details the current status of revision TKA through 2022. While infection and aseptic loosening remain leading causes, we found a low aseptic loosening rate of 12.8%.

Uncemented trabecular metal high-flex posterior-stabilized monoblock total knee arthroplasty in patients aged 60 years or younger

BACKGROUND

Uncemented trabecular metal (TM) monoblock tibial components in total knee arthroplasty (TKA) have shown excellent clinical results for up to 10 years. However, these studies were performed in highly specialized units, with few surgeons and often excluding knees with secondary osteoarthritis (OA), severe malalignments and previous surgery. The purpose of this study was to investigate implant survivorship and clinical and radiological outcome of the uncemented TM high-flex posterior stabilized (PS) monoblock tibial component in routine clinical practice.

METHODS

A retrospective study of 339 knees (282 patients) operated with the implant in routine clinical practice at two hospitals on patients aged 60 years or younger between 2007 and 2015. The operations were performed by 12 surgeons and there were no specific contraindications for use of the implant. Follow up ended in 2020. The status of the implant of deceased patients at death and those not attending follow up was checked with the Swedish Knee Arthroplasty Register. Clinical follow up consisted of clinical investigation, PROMs, and knee X-ray.

RESULTS

Follow up was mean (range) 8.5 (5-13.8) years, and the 8-year survival rate was 0.98 (standard error 0.007). Five patients five knees) were deceased, five knees were revised (none due to aseptic loosening), and 16 patients did not attend the clinical follow up. Forty-four percent of the knees had secondary OA and 45% had had previous operations. 93% were satisfied or very satisfied with the operation and forgotten joint score (FJS) was median (interquartile range) 81 (44-94). Radiographic analysis revealed bone in close contact with the tibial tray and pegs in most cases, and in only 2% of the knees were potential radiolucent lines found.

CONCLUSION

The results indicate that this uncemented implant performs excellently in routine clinical practice and also in younger patients with secondary OA or previous knee operations.

New Horizons of Cementless Total Knee Arthroplasty

BACKGROUND

Considering the increasing number of young and active patients needing TKA, orthopedic surgeons are looking for a long-lasting and physiological bond for the prosthetic implant. Multiple advantages have been associated with cementless fixation including higher preservation of the native bone stock, avoidance of cement debris with subsequent potential third-body wear, and the achievement of a natural bond and osseointegration between the implant and the bone that will provide a durable and stable fixation.

DISCUSSION

Innovations in technology and design have helped modern cementless TKA implants to improve dramatically. Better coefficient of friction and reduced Young's modulus mismatch between the implant and host bone have been related to the use of porous metal surfaces. Moreover, biologically active coatings have been used on modern implants such as periapatite and hydroxyapatite. These factors have increased the potential for ingrowth by reducing micromotion and increasing osteoconductive properties. New materials with better biocompatibility, porosity, and roughness have been introduced to increase implant stability.

CONCLUSIONS

Innovations in technology and design have helped modern cementless TKA implants improve primary stability in both the femur and tibia. This means that short-term follow-up are comparable to cemented. These positive prognostic factors may lead to a future in which cementless fixation may be considered the gold-standard technique in young and active patients.

Engaging Patients and Caregivers to Develop a Patient-Centered Agenda for Comparative Effectiveness Research Focused on the Treatment of Complex Knee Problems

Complex articular cartilage loss in the knee is being diagnosed more frequently and earlier in life, and patients are faced with major decisions regarding invasive surgical interventions at increasingly younger ages. There is a critical unmet need to provide patient-centered comparative effectiveness research for the hundreds of thousands of patients faced with these treatment decisions each year. Toward filling the need, we developed the Patient AdvisoR Team iN Orthopaedic ReSearch (PARTNORS) program. We recruited a diverse group of patients and caregivers with lived experiences in dealing with complex knee problems to define patient-centered research priorities for comparative biological and artificial knee surgery research for middle-aged adults. Adapting the Stakeholder Engagement in Question Development and Prioritization Method, PARTNORS defined a 20-question list of patient-centered research questions of factors influencing a patients' choice between biological and artificial knee surgeries. The highest prioritized research question related to functional level postsurgery as it relates to daily activities and recreational activities. The second highest prioritized research questions related to insurance coverage and financial costs. Other prioritized research areas included caregiving needs, implant longevity, recovery and rehabilitation time, patient satisfaction and success rates, individual characteristics, and risks. By engaging a group of patients and caregivers and including them as members of a multidisciplinary research team, comparative effectiveness research that includes patient-centered factors that go beyond typical clinical success indicators for knee surgery can be designed to allow physicians and patients to work together toward evidence-based shared decisions. This shared decision-making process helps to align patients' and health care team's goals and expectations to improve outcomes.

Cementless metal-backed patellar components in primary total knee arthroplasty using an implant of modern design

Aims

The use of cementless total knee arthroplasty (TKA) components has increased during the past decade. The initial design of cementless metal-backed patellar components had shown high failure rates due to many factors. The aim of this study was to evaluate the clinical results of a second-generation cementless, metal-backed patellar component of a modern design.

Methods

This was a retrospective review of 707 primary TKAs in 590 patients from a single institution, using a cementless, metal-backed patellar component with a mean follow-up of 6.9 years (2 to 12). A total of 409 TKAs were performed in 338 females and 298 TKAs in 252 males. The mean age of the patients was 63 years (34 to 87) and their mean BMI was 34.3 kg/m2 (18.8 to 64.5). The patients were chosen to undergo a cementless procedure based on age and preoperative radiological and intraoperative bone quality. Outcome was assessed using the Knee Society knee and function scores and range of motion (ROM), complications, and revisions.

Results

A total of 24 TKAs (3.4%) in 24 patients failed and required revision surgery, of which five were due to patellar complications (0.71%): one for aseptic patellar loosening (0.14%) and four for polyethylene dissociation (0.57%). A total of 19 revisions (2.7%) were undertaken in 19 patients for indications which did not relate to the patella: four for aseptic tibial loosening (0.57%), one for aseptic femoral loosening (0.14%), nine for periprosthetic infection (1.3%), one for popliteus impingement (0.14%), and four for instability (0.57%). Knee Society knee and function scores, and ROM, improved significantly when comparing pre- and postoperative values. Survival of the metal-backed patellar component for all-cause failure was 97.5% (95% confidence interval 94.9% to 100%) at 12 years.

Conclusion

The second-generation cementless TKA design of metal-backed patellar components showed a 97.5% survival at 12 years, with polyethylene dissociation from the metal-backing being the most common cause of patellar failure. In view of the increased use of TKA, especially in younger, more active, or obese patients, these findings are encouraging at mean follow-up of seven years.

Survivorship and Clinical Outcomes of Primary Total Knee Arthroplasty Performed in Patients 35 Years of Age and Younger

BACKGROUND

Total knee arthroplasties (TKAs) for patients aged ≤35 years are rare but necessary for patients who have diseases such as juvenile idiopathic arthritis, osteonecrosis, osteoarthritis, and rheumatoid arthritis. Few studies have examined the 10-year and 20-year survivorship and clinical outcomes of TKAs for young patients.

METHODS

A retrospective registry review identified 185 TKAs in 119 patients aged ≤ 35 years performed between 1985 and 2010 at a single institution. The primary outcome was implant survivorship free of revision. Patient-reported outcomes were assessed at 2 time points: 2011 to 2012 and 2018 to 2019. The average age was 26 years (range, 12 to 35). Mean follow-up was 17 years (range, 8 to 33).

RESULTS

Survivorship decreased from 84% (95% confidence interval [CI]: 79 to 90) at 5 years to 70% (95% CI: 64 to 77) at 10 years and to 37% (95% CI: 29 to 45) at 20 years. The most common reasons for revision were aseptic loosening (6%) and infection (4%). Risk factors for revision included increasing age at time of surgery (Hazards Ratio [HR] 1.3, P = .01) and use of constrained (HR 1.7, P = .05) or hinged prostheses (HR 4.3, P = .02). There were 86% of patients reporting that their surgery resulted in "a great improvement" or better.

CONCLUSION

Survivorship of TKAs in young patients is less favorable than expected. However, for the patients who responded to our surveys, TKA demonstrated substantial pain relief and improvement in function at 17-year follow-up. Revision risk increased with older age and higher levels of constraint.

Highly lubricious SPMK-g-PEEK implant surfaces to facilitate rehydration of articular cartilage

To enable long lasting osteochondral defect repairs which preserve the native function of synovial joint counter-face, it is essential to develop surfaces which are optimised to support healthy cartilage function by providing a hydrated, low friction and compliant sliding interface. PEEK surfaces were modified using a biocompatible 3-sulfopropyl methacrylate potassium salt (SPMK) through UV photo-polymerisation, resulting in a ∼350 nm thick hydrophilic coating rich in hydrophilic anionic sulfonic acid groups. Characterisation was done through Fourier Transformed Infrared Spectroscopy, Focused Ion Beam Scanning Electron Microscopy, and Water Contact Angle measurements. Using a Bruker UMT TriboLab, bovine cartilage sliding tests were conducted with real-time strain and shear force measurements, comparing untreated PEEK, SPMK functionalised PEEK (SPMK-g-PEEK), and Cobalt Chrome Molybdenum alloy. Tribological tests over 2.5 h at physiological loads (0.75 MPa) revealed that SPMK-g-PEEK maintains low friction (μ< 0.024) and minimises equilibrium strain, significantly reducing forces on the cartilage interface. Post-test analysis showed no notable damage to the cartilage interfacing against the SPMK functionalised surfaces. The application of a constitutive biphasic cartilage model to the experimental strain data reveals that SPMK surfaces increase the interfacial permeability of cartilage in sliding, facilitating fluid and strain recovery. Unlike previous demonstrations of sliding-induced tribological rehydration requiring specific hydrodynamic conditions, the SPMK-g-PEEK introduces a novel mode of tribological rehydration operating at low speeds and in a stationary contact area. SPMK-g-PEEK surfaces provide an enhanced cartilage counter-surface, which provides a highly hydrated and lubricious boundary layer along with supporting biphasic lubrication. Soft polymer surface functionalisation of orthopaedic implant surfaces are a promising approach for minimally invasive synovial joint repair with an enhanced bioinspired polyelectrolyte interface for sliding against cartilage. These hydrophilic surface coatings offer an enabling technology for the next generation of focal cartilage repair and hemiarthroplasty implant surfaces.

Why and What Happens to Patients Younger Than 60 Years Who Need Revision Total Knee Arthroplasty?

BACKGROUND

With the increasing number of young patients undergoing primary total knee arthroplasty (TKA), there will be an increase in the number of patients who require revision. While the results of TKA in younger patients are well known, there is little information regarding to the outcomes of revision TKA in this population. The purpose of this study was to evaluate the clinical outcomes in patients <60 years of age undergoing aseptic revision TKA.

METHODS

We retrospectively reviewed 433 patients undergoing aseptic revision TKA between 2008 and 2019. There were 189 patients <60 years compared to a group of 244 patients >60 years undergoing revision TKA for aseptic failures in terms of implant survivorships, complications, and clinical outcomes. Patients were followed for a mean of 48 months (range, 24 to 149).

RESULTS

A total of 28 (14.8%) patients less than 60 years of age required repeat revision compared to 25 (10.2%) 60 years or older (odds ratio (OR) 1.94, 95% confidence interval (CI) 0.73-5.22, P = .187). There were no differences regarding postprocedural Patient-Reported Outcomes Measurement Information System (PROMIS) physical health scores (72.3 ± 13.7 versus 72.0 ± 12.0, P = .66) and PROMIS mental health scores (66.6 ± 17.4 versus 65.8. ± 14.7, P = .72), at an average of 32.9 and 30.7 months, respectively. Postoperative infection occurred in 3 (1.6%) patients <60 years of age, while 12 (4.9%) postoperative infections occurred in patients 60 years or older (OR 0.75, 95% CI 0.06-10.2, P = .83).

CONCLUSION

There were no statistically significant differences in clinical outcomes between patients <60 versus > 60 years of age undergoing aseptic revision TKA.

Does interaction occur between risk factors for revision total knee arthroplasty?

INTRODUCTION

Several risk factors for revision TKA have previously been identified, but interactions between risk factors may occur and affect risk of revision. To our knowledge, such interactions have not been previously studied. As patients often exhibit multiple risk factors for revision, knowledge of these interactions can help improve risk stratification and patient education prior to TKA.

MATERIALS AND METHODS

The State Inpatient Databases (SID), part of the Healthcare Cost and Utilization Project (HCUP), were queried to identify patients who underwent TKA between January 1, 2006 and December 31, 2015. Risk factors for revision TKA were identified, and interactions between indication for TKA and other risk factors were analyzed.

RESULTS

Of 958,944 patients who underwent TKA, 33,550 (3.5%) underwent revision. Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA were significantly associated with revision (p < 0.05). Age was the strongest predictor (p  < 0.0001), with younger patients exhibiting higher revision risk. Risks associated with age were modified by an interaction with indication for TKA (p < 0.0001). There was no significant interaction between sex and indication for TKA (p = 0.535) or race and indication for TKA (p = 0.187).

CONCLUSIONS

Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA are significantly associated with revision TKA. Interaction occurs between age and indication.

Functional Outcomes of Knee Arthrodesis for Infected Total Knee Arthroplasty

INTRODUCTION

As the occurrence of total knee arthroplasties (TKAs) is forecasted to continue rising, so too will the frequency of prosthetic joint infections (PJIs) and revision TKAs. Multiple revisions can result in an unreconstructible knee. In such instances, the knee may be salvaged through arthrodesis. We evaluated whether height, BMI, and age impacted patient-reported outcome measures (PROMs) in patients who underwent knee arthrodesis after revision TKA due to PJI.

METHODS

We conducted a retrospective review of patients undergoing arthrodesis for an infected TKA at a dedicated orthopedic infection service from 2014 to 2022. Patient demographics and PROMs from 36-Item Short Form Survey (SF-36) and Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaires were collected. Correlation analysis was performed to determine if any association between height, BMI, and age was present with the various PROMs and sub-scores.

RESULTS

Forty-four patients (19 males, 25 females) were included, with a mean follow-up of 48 months. Increases in height (>166 cm), BMI (>30), and age (>62 years) had a statistically significant negative impact on three SF-36 components: health changes (P = 0.016), physical functioning ability (P = 0.0096), and general health components (P = 0.0075).

CONCLUSION

Our results suggest that a knee arthrodesis is an acceptable option in patients with a persistent knee PJI with good functional PROMs and ambulatory status. Patients with shorter height, lower BMI, and younger age showed overall better outcomes. Knee arthrodesis can be an alternative option for amputation in patients with an infected TKA and provide good functional outcomes in selected patients.

The BioPoly Partial Resurfacing Knee Implant Provides Beneficial Clinical Outcomes: A Concise Follow-up, at 5 Years, of a Previous Report

Abstract

We previously conducted a single-arm, prospective study in which 31 patients (mean age [and standard deviation], 42.5 ± 11.3 years) with cartilage lesions were treated with use of the BioPoly Partial Resurfacing Knee Implant. Treatment outcomes were compared with those reported for the standard of care, microfracture. We found that the mean KOOS (Knee injury and Osteoarthritis Outcome Score) Quality of Life score at 5 years in the BioPoly cohort was noninferior to (p = 0.004), and indeed greater than (p = 0.021), that in the microfracture cohort. The BioPoly cohort demonstrated improvement in the mean scores for all KOOS domains at every postoperative time point (p < 0.025). The mean score for the visual analog scale (VAS) for pain significantly improved (p < 0.025) at all time points up to 4 years and trended toward significant improvement at 5 years (p = 0.027). This study indicated that the BioPoly implant was safe, provided significant improvement starting at 6 months and continuing to 5 years, and provided greater improvement than microfracture for some outcome measures.

Level of Evidence

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

Increased complications rates and inferior patient reported outcomes following total knee arthroplasty due to post-traumatic osteoarthritis with previous fracture treatment: a systematic review

PURPOSE

This study aims to present the existing literature relating to patient-reported outcome measures (PROMs) and complications in patients undergoing total knee arthroplasty (TKA) due to posttraumatic osteoarthritis (PTOA) with prior fracture treatment around the knee compared with patients who underwent TKA because of primary osteoarthritis (OA).

METHODS

A systematic review was undertaken and synthesised in accordance with the PRISMA guidelines by searching existing literature in the following databases: PubMed, Scopus, Cochrane Library and EMBASE. A search string according to the PECO was used. After analysing 2781 studies, 18 studies (5729 PTOA patients/149,843 OA patients) were included for a final review. An analysis revealed that 12 (67%) were retrospective cohort studies, four (22%) were register studies and the remaining two (11%) were prospective cohort studies. The mean Critical Appraisal Skills Programme (CASP) score was 23.6 out of 28, signifying studies of moderate quality.

RESULTS

The most frequently reported outcome measure were postoperative complications, reported in all eighteen studies. Intraoperative complications were reported in ten (4165 PTOA/124.511 OA) and patient-reported outcome measures (PROMs) in six studies (210 PTOA/2768 OA). A total of nine different PROMs were evaluated. As far as PROMs were concerned, the scores were inferior for PTOA but did not differ statistically from OA, except for one study, which favoured the OA group. Across all studies, postoperative complications were higher in the PTOA group, reporting infections as the most common complication. Furthermore, a higher revision rate was reported in the PTOA group.

CONCLUSION

PROM analysis suggests that both patient groups benefit from a TKA in terms of functional outcome and pain relief, however, patient-reported outcomes could be inferior for PTOA patients. There is consistent evidence for increased complication rates following PTOA TKA. Patients undergoing TKA due to PTOA after fracture treatment should be informed about the risk for inferior results and refrain from comparing their knee function to patients with TKA after OA. Surgeons should be aware of the challenges that PTOA TKA poses.

LEVEL OF EVIDENCE

Level III.

2-year results of middle-aged patients with two-compartment cartilage lesions in one knee treated with two patient specific metal implants

PURPOSE

Focal chondral lesions of the femur are currently treated with biological repair or arthroplasty. However, some patients are not suitable for either one due to lesion size, age, or prior biological treatment attempts. While singular patient-specific focal mini metal implants already showed good results, the outcomes of bicompartmental implantation of these implants have not been discussed in the literature yet. This study aims to evaluate clinical outcomes of patients who underwent bicompartmental implantation of two patient-specific implants.

METHODS

This prospective, non-randomized, non-comparative pilot study evaluates results up to two years after bicompartmental implantation of two implants (Episealer Implant, Episurf, Stockholm, Sweden). A damage report is compiled using a special MRI program and patient specific implants are manufactured, including 3D-printed surgical instruments to provide exact placement of the implant. The patients were assessed repeatedly using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analogue Scale (VAS) for pain during the follow-up.

RESULTS

The scores were evaluated three, 12, and 24 months after surgery and showed good results. The median in both scores improved from 37.7 for the KOOS5 preoperatively to 69.1 after 24 months and from 69 for the VAS for pain preoperatively to 9 after 24 months.

CONCLUSION

Overall, for the small study group presented, the early results are promising. With noticeable improvement in KOOS and VAS for pain after two years, patient specific implants appear to become relevant in future standardized treatment of femoral chondral lesions. Especially with bicompartmental implantation, full arthroplasty can be delayed even further.

LEVEL OF EVIDENCE

IV.

Does high activity after total and unicompartmental knee arthroplasty increase the risk for aseptic revision?

INTRODUCTION

It has been suggested that high activity might negatively impact implant survival following total and unicompartmental knee arthroplasty (TKA/UKA) and many surgeons advise their patients to only participate in moderate level sport activities. To date, it remains unclear whether such restraints are necessary to assure longevity of the implants.

MATERIALS AND METHODS

We conducted a retrospective study on 1906 knees (1745 TKA, 161 UKA) in 1636 patients aged 45-75 years who underwent primary arthroplasty for primary osteoarthritis. Lower extremity activity scale (LEAS) at a two year follow-up was assessed to define the activity level. Cases were grouped in low (LEAS ≤ 6), moderate (LEAS 7-13) and high activity (LEAS ≥ 14). Cohorts were compared with Kruskal-Wallis- or Pearson-Chi2-Test. Univariate logistic regression was conducted to test for association between activity level at two years and later revisions. Odds ratio was reported and converted to predicted probability. A Kaplan-Meier curve was plotted to predict implant survival.

RESULTS

The predicted implant survival for UKA was 100.0% at two years and 98.1% at five years. The predicted implant survival for TKA was 99.8% at two years, 98.1% at five years. The difference was not significant (p = 0.410). 2.5% of the UKA underwent revision, one knee in the low and three knees in the moderate activity group, differences between the moderate and high activity group were not significant (p = 0.292). The revision rate in the high activity TKA group was lower than in the low and moderate activity groups (p = 0.008). A higher LEAS two years after surgery was associated with a lower risk for future revision (p = 0.001). A one-point increase in LEAS two years after surgery lowered the odds for undergoing revision surgery by 19%.

CONCLUSIONS

The study suggests that participating in sports activity following both UKA and TKA is safe and not a risk factor for revision surgery at a mid-term follow-up. Patients should not be prevented from an active lifestyle following knee replacement.

Incidence and risk factors of in-hospital prosthesis-related complications following total shoulder arthroplasty

BACKGROUND

The occurrence of prosthesis-related complications after total shoulder arthroplasty is devastating and costly. The purpose was to determine the incidence and risk of in-hospital prosthesis-related complications after total shoulder arthroplasty utilizing a large-scale sample database.

METHODS

A retrospective database analysis was performed based on Nationwide Inpatient Sample from 2010 to 2014. Patients who underwent total shoulder arthroplasty were included. Patient demographics, hospital characteristics, length of stay, economic indicators, in-hospital mortality, comorbidities, and peri-operative complications were evaluated.

RESULTS

A total of 34,198 cases were capture from the Nationwide Inpatient Sample database. There were 343 cases of in-hospital prosthesis-related complications after total shoulder arthroplasty and the overall incidence was 1%, with a more than 2.5-fold decrease from 2010 to 2014. Dislocation was the most common category among prosthesis-related complications (0.1%). The occurrence of in-hospital prosthesis-related complications was associated with significantly more total charges and slightly longer length of stay while less usage of Medicare. Risk factors of prosthesis-related complications were identified including younger age (<64 years), female, the native American, hospital in the South, alcohol abuse, depression, uncomplicated diabetes, diabetes with chronic complications, fluid and electrolyte disorders, metastatic cancer, neurological disorders, and renal failure. Interestingly, advanced age (≥65 years) and proprietary hospital were found as protective factors. Furthermore, prosthesis-related complications were associated with aseptic necrosis, rheumatoid arthritis, rotator cuff tear arthropathy, Parkinson's disease, prior shoulder arthroscopy, and blood transfusion.

CONCLUSIONS

It is of benefit to study risk factors of prosthesis-related complications following total shoulder arthroplasty to ensure the appropriate management and optimize consequences although a relatively low incidence was identified.

Short-term clinical outcomes of primary total knee arthroplasty with a new-type kinematic retaining implant: A comparison with preexisting cruciate retaining prosthesis

Despite the success of total knee arthroplasty (TKA), current implant designs could not consistently restore the physiological knee kinematics, especially in cruciate-retaining (CR) implants. This study aimed to investigate the short-term clinical outcomes, particularly patient satisfaction, of primary TKA employing a new-type kinematic retaining (KR) implant. We analyzed 149 cases applied the KR implant at our institutions during June 2017 to May 2019. The effectiveness of this implant design was compared with another CR one (171 cases). Both groups underwent primary TKA in the same period and all patients completed 2 years of follow-up. Perioperative changes in range of motion (ROM), Knee Score, function score, and patient satisfaction by Forgotten Joint Score-12 (FJS-12) method were evaluated. Postoperative ROM, Knee Score, and function score were significantly improved at 1 year after surgeries and maintained for another year in both KR and CR groups. The improvement rate of ROM in KR group (108.1%) was substantially higher than that in CR (104.5%), even 4% increase could have affected patients' satisfaction in a real-world setting. Regarding the patient satisfaction, such 4 items as climbing stairs, walking on a bumpy road, doing housework or gardening, and taking a walk or hiking were significantly enhanced in KR cases compared to CR. There were no loosening or revision cases and the short-term survivorships of both implants were 100%. In addition, there has been no case of obvious complications in both groups during and after surgeries. The results of the present study suggest that this novel KR prosthesis can reproduce physiological knee kinematics, recover its functions, and contribute to pain relief after TKA. TKA procedure using the KR implant should be a good surgical option to improve postoperative outcomes.

Evaluation of the changes in incidence and patient age of knee arthroscopy along with changes in time between knee arthroscopy and arthroplasty between 1998 and 2018: a nationwide register study

BACKGROUND

Recent evidence has led to guidelines to refrain from recommending knee arthroscopy for patients with an osteoarthritis diagnosis. The aim of this study was to evaluate the latest changes in the incidence of arthroscopic surgery for degenerative knee disease, changes in the ages of those patients and the delay between knee arthroscopy and arthroplasty, in Finland between 1998 and 2018.

METHOD

The data for were collected from the Finnish National Hospital Discharge Register (NHDR). All knee arthroplasties and arthroscopies performed due to osteoarthritis, degenerative meniscal tears, and traumatic meniscal tears were included. Incidence rates (per 100,000 person-years) as well as the median age of patients were calculated.

RESULTS

The incidence of arthroscopy decreased 74% (413 to 106 per 100,000 person-years) and knee arthroplasty increased 179% (94 to 262 per 100,000 person-years) between 1998 and 2018. The incidence of all arthroscopies increased until 2006. Subsequently, the incidence of arthroscopy due to OA decreased by 91% and arthroscopic partial meniscectomy (APM) for degenerative meniscal tears decreased by 77% until 2018. The decrease of traumatic meniscal tears begun later, leading to decrease of 57% between 2011 and 2018. Conversely, the incidence of patients undergoing APM of traumatic meniscal tear increased 375%. The median age of patients who underwent knee arthroscopy decreased from 51 to 46 and from 71 to 69 in knee arthroplasty patients.

CONCLUSIONS

Increasing evidence that recommends refraining from knee arthroscopy in OA and degenerative meniscal tears has led to a dramatic decrease in the incidence of arthroscopies. Simultaneously, the median age of the patients who undergo these operations has continued to decrease.

Improved 2-Year Freedom from Arthroplasty in Patients with High-Risk SIFK Scores and Medial Knee Osteoarthritis Treated with an Implantable Shock Absorber versus Non-Operative Care

OBJECTIVE

Subchondral insufficiency fracture of the knee (SIFK) is associated with high rates of osteoarthritis (OA) and arthroplasty. The implantable shock absorber (ISA) is an extra-capsular implant that unloads the medial knee compartment. This study compared the 2-year freedom from arthroplasty rates in subjects with medial knee OA and SIFK when treated with an ISA versus a matched cohort of patients treated non-surgically.

DESIGN

This retrospective case-control study compared 2-year conversion rates to arthroplasty in SIFK score-, age-, and body mass index (BMI)-matched control subjects without prior surgical history with ISA-implanted subjects from an ongoing prospective study. Baseline and final radiographs, and MRIs were reviewed for evaluation of meniscus or ligament injuries, insufficiency fractures, and subchondral edema. Kaplan-Meier analysis assessed survival.

RESULTS

Forty-two patients (21 Control: 21 ISA), mean age = 52.3 ± 8.7 years, BMI = 29.5 ± 3.9 kg/m2, 40% female were evaluated. Both ISA and Control arms had the same numbers of low (n = 4), medium (n = 11), and high-risk (n = 6) SIFK scores. One- and 2-year freedom-from-arthroplasty rates were both 100% for ISA subjects, and 76% and 55%, respectively, for Controls (P = 0.001 for cross-group comparison). Control knees with low, medium, and high-risk SIFK scores had respective 1- and 2-year survival rates of 100% and 100%, 90% and 68% (P = 0.07 vs. ISA), and 33% and 0% (P = 0.002 vs. ISA).

CONCLUSIONS

ISA intervention was strongly associated with avoidance of arthroplasty at a minimum 2 years, especially in patients with high-risk SIFK scores. SIFK severity scoring predicted relative risk of conversion to arthroplasty through at least 2 years in non-surgically treated subjects.

Cementless Compared to Cemented Total Knee Arthroplasty is Associated With More Revisions Within 1 Year of Index Surgery

Background

Cementless total knee arthroplasties (TKAs) have gained renewed interest due to improved implant designs and lower rates of revision than its cemented counterparts. The purpose of this study was to compare revision rates between cemented vs cementless TKAs within 1 year of primary arthroplasty.

Methods

This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had undergone cemented and cementless TKAs and subsequent surgical revisions. An unadjusted univariate analysis of patient demographics, Charlson Comorbidity Index score, and surgical revisions at 90 days and 1 year after TKA was performed using chi-squared testing. Multivariate logistic regression analyses were subsequently performed for 1-year surgical complications requiring revision.

Results

Of 324,508 patients, 312,988 (96.45%) underwent cemented TKAs, and 11,520 (3.55%) underwent cementless TKAs. Patients undergoing cementless TKA tended to be younger than patients undergoing cemented TKA (63.67 ± 9.15 cementless vs 66.22 ± 8.85 cemented, P < .001). Univariate chi-squared testing showed that cementless patients were more likely to require 1-component femoral or tibial revision at 90 days and 1 year, irrigation and debridement at 90 days and 1 year, and arthroscopy with lysis of adhesions at 1 year only. Similar findings were observed for these 3 revision procedures at 1 year after correcting for age, gender, and Charlson Comorbidity Index score using multivariate logistic regression analysis as cementless TKA patients had higher odds ratios for each of the revisions.

Conclusions

Small but significant differences were found in surgical revisions among cementless TKAs when compared to cemented TKAs within 1 year of the index procedure.

Cementless Metal-Backed Patellar Components in Primary Total Knee Arthroplasty: An Average 10-Year Follow-Up

BACKGROUND

Historically, 1st generation metal-backed cementless patellar implants demonstrated high failure rates due to multiple factors. The 2nd generation cementless implants were developed with purported improvements in component design and polyethylene wear characteristics. This study evaluated clinical results of a current generation cementless metal-backed patellar implant with a minimum 5-year follow-up.

METHODS

One hundred and thirty-six primary total knee arthroplasties (TKAs) with metal-backed cementless patellae were compared to 183 cemented patellae with the same implant design. The cementless group mean age was 61 years (range, 40 to 81), mean body mass index (BMI) of 34.9 (range, 22.6 to 64.5), and mean follow-up of 10 years (range, 5 to 13). The cemented group mean age was 65 years (range, 32 to 89), mean BMI of 32.5 (range, 18.2 to 56.6), and mean follow-up of 10 years (range, 5 to 12). Significant demographic differences of age (P < .001), BMI (P < .01), and sex (P < .001) were found, with cementless patients being younger, heavier, and with more men.

RESULTS

There were no statistical differences in non-revision procedures (P = .214), TKA revisions (P = .639), patellar revisions (P = .151), and patellar aseptic loosening (P = .737). The 10-year survivorship of the cementless metal-backed patella was 95.9% with all-cause failure as the endpoint. The 10-year survivorship of the cemented patellar component was 98.9%.

CONCLUSION

This study demonstrated noninferiority of a 2nd generation HA-coated cementless metal-backed patellar implant in primary TKA compared to cemented patellae with 10-year survivorship of 95.9%. Advances in implant design and polyethylene wear properties have led to improved clinical results with metal-backed patellar components in primary TKA.

Implantable Shock Absorber Provides Superior Pain Relief and Functional Improvement Compared With High Tibial Osteotomy in Patients with Mild-to-Moderate Medial Knee Osteoarthritis: A 2-Year Report

OBJECTIVE

Up to 10 million Americans below the age of 65 years have symptomatic knee osteoarthritis (OA) and may not yet be candidates for arthroplasty. In response, a subcutaneous implantable shock absorber (ISA) that unloads the knee has been developed. The safety and effectiveness of ISA treatment were compared against a surgical unloading control, high tibial osteotomy (HTO).

DESIGN

This was a prospective open-label cohort study with a historical control arm. Subjects underwent ISA placement or HTO. The primary endpoint was a composite variable combining pain, function, specific adverse events, integrity of implant or hardware, and conversion to subsequent surgery. Pain and function outcomes (Western Ontario and McMaster Universities Arthritis Index scores) were assessed through 24 months. Adverse events were tracked.

RESULTS

The primary endpoint demonstrated superiority of the ISA arm versus the HTO arm, with 85.6% of ISA subjects meeting all criteria compared with 65.5% of HTO subjects. In addition, all 5 secondary endpoints showed superiority of ISA over HTO. At 24 months, the proportions of subjects considered responders were 95.8% (ISA) versus 87.9% (HTO) for pain and 91.7% (ISA) versus 81.3% (HTO) for function. The ISA procedure was well tolerated, with 13.4 days to full weightbearing status versus 58.0 days for the HTO arm.

CONCLUSIONS

Treatment with an ISA demonstrated noninferiority and superiority versus treatment with HTO in subjects aged 25-65 years who had OA of the medial knee. Treatment with ISA has high clinical benefit and is durable through at least 24 months.

Impact of time to revision total knee arthroplasty on outcomes following aseptic failure

INTRODUCTION

Prior studies have demonstrated an association between time to revision total knee arthroplasty (rTKA) and indication; however, the impact of early versus late revision on post-operative outcomes has not been reported.

MATERIALS AND METHODS

A retrospective, observational study examined patients who underwent unilateral, aseptic rTKA at an academic orthopedic hospital between 6/2011 and 4/2020 with > 1-year of follow-up. Patients were early revisions if they were revised within 2 years of primary TKA (pTKA) or late revisions if revised after greater than 2 years. Patient demographics, surgical factors, and post-operative outcomes were compared.

RESULTS

470 rTKA were included (199 early, 271 late). Early rTKA patients were younger by 2.5 years (p = 0.002). The predominant indications for early rTKA were instability (28.6%) and arthrofibrosis/stiffness (26.6%), and the predominant indications for late rTKA were aseptic loosening (45.8%) and instability (26.2%; p < 0.001). Late rTKA had longer operative times (119.20 ± 51.94 vs. 103.93 ± 44.66 min; p < 0.001). There were no differences in rTKA type, disposition, hospital length of stay, all-cause 90-day emergency department visits and readmissions, reoperations, and number of re-revisions.

CONCLUSIONS

Aseptic rTKA performed before 2 years had different indications but demonstrated similar outcomes to those performed later. Early revisions had shorter surgical times, which could be attributed to differences in rTKA indication.

LEVEL OF EVIDENCE

III, retrospective observational analysis.

An implantable shock absorber yields an 85% survival-from-arthroplasty rate through 5 years in working-age patients with medial compartment knee osteoarthritis

PURPOSE

To evaluate the 5-year rate of survival without undergoing arthroplasty or high tibial osteotomy (HTO) in subjects with mild-to-moderate medial compartment knee osteoarthritis (OA) who were treated with an implantable shock absorber (ISA) system.

METHODS

Three prospective, sequential, multicenter, international, single-arm clinical trials were conducted comprising subjects who received an ISA for symptomatic medial knee OA after failing ≥ 6 months of conservative therapy. Study outcomes were analyzed cumulatively and by enrollment group when all subjects' follow-up data exceeded the 2-year threshold after ISA implantation. Primary outcome was survival rate without conversion to arthroplasty/HTO. Secondary outcomes were changes in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and function scores after ISA implantation.

RESULTS

All 171 enrolled subjects (age 51 ± 9 years, body-mass index 28.5 ± 3.5 kg/m², 38% female; study knee Kellgren-Lawrence score 2.7 ± 0.9 points) were followed for a minimum of 2, and up to 5, years after device implantation. Overall, 90.6% (155/171) of subjects survived without requiring arthroplasty/HTO at last follow-up (mean 3.2 ± 1.6 years). The Kaplan-Meyer median 3- and 5-year survival-without-arthroplasty point estimates were 89.8% (95% CI 86.5‒95.7%) and 84.9% (95% CI 75.1‒91.1%), respectively. The median 3-year estimated survival rate for the most recent study (n = 81) was 97.3%. The mean WOMAC Pain score decreased 71% from baseline to last follow-up after ISA implantation, from 58 ± 13 to 16 ± 17 points (p < 0.0001). The Function score improved 69%, decreasing from 56 ± 18 to 17 ± 17 points (p < 0.0001).

CONCLUSIONS

In younger patients with mild-to-moderate symptomatic medial compartment knee OA, implantation of the ISA device resulted in a 5-year survival rate of 85% from undergoing arthroplasty or HTO. The ISA system may be an effective treatment option for working-age patients with medial knee OA who are not candidates for or do not desire more invasive surgical approaches.

LEVEL OF EVIDENCE

II.

Initial Outcomes After Unicompartmental Tibiofemoral Bipolar Osteochondral and Meniscal Allograft Transplantation in the Knee Using MOPS-Preserved Fresh (Viable) Tissues

BACKGROUND

Unicompartmental tibiofemoral bipolar osteochondral allograft transplantation (OCAT) with meniscal allograft transplantation (MAT) has not historically been associated with consistently successful outcomes for treatment of knee articular cartilage defects with meniscal deficiency.

HYPOTHESIS

Primary OCAT and MAT using fresh tissues will be associated with successful short-term outcomes based on statistically significant and clinically meaningful improvements in pain and function in the majority of patients.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients were prospectively enrolled into a registry for outcomes after OCAT and MAT. Patients included those who underwent primary OCAT and MAT using Missouri Osteochondral Preservation System (MOPS)-preserved allografts for treatment of large bipolar tibiofemoral articular cartilage defects with meniscal deficiency and had a minimum of 2-year follow-up data.

RESULTS

A total of 76 patients (n = 52 male; 68%) met inclusion criteria (mean follow-up, 52 months). The mean age was 41.1 years (range, 15-69 years), and the mean body mass index was 28.9 (range, 17-46); 48 patients underwent another OCAT in addition to the unicompartmental bipolar tibiofemoral OCAT and MAT; 23 patients (30.3%) were documented to be nonadherent to the prescribed postoperative restriction and rehabilitation protocol. The initial success rate (>2 years) was 77.6%, with 8 patients (10.5%) undergoing revision and 9 (11.8%) converting to arthroplasty. Variables associated with an increased risk for treatment failure (revision or arthroplasty) included ipsilateral osteotomy (P = .046; odds ratio [OR] = 3.3), ipsilateral concurrent procedure (P = .0057; OR = 5.5), and nonadherence (P = .0009; OR = 7.2). None of the patients undergoing revision surgery required arthroplasty at the time of data analysis such that the overall success rate for primary and revision unicompartmental bipolar OCA plus MAT was 88.2%. There were statistically significant (P < .0001) and clinically important improvements for all patient-reported outcomes at each annual follow-up time point.

CONCLUSION

Unicompartmental tibiofemoral bipolar OCAT and MAT can result in successful short-term outcomes (2-6 years) and satisfaction in the majority of patients (78%). Primary MOPS-preserved OCAT with MAT for treatment of femoral condyle and tibial plateau articular cartilage defects with concurrent meniscal deficiency was associated with statistically significant and clinically meaningful improvements in patient-reported measures of pain and function.

The Impact of Frailty Is Age Dependent in Patients Undergoing Primary Total Knee Arthroplasty: The Age-Adjusted Modified Frailty Index

BACKGROUND

Frailty is a well-established risk factor in patients undergoing total knee arthroplasty (TKA). How age modifies the impact of frailty on outcomes in these patients, however, remains unknown. In this study, we aimed to describe and evaluate the applicability of a novel risk stratification tool-the age-adjusted modified Frailty Index (aamFI)-in patients undergoing TKA.

METHODS

A national database was queried for all patients undergoing primary TKA from 2015 to 2019. There were 271,271 patients who met inclusion criteria for this study. First, outcomes were compared between chronologically young and old frail patients. In accordance with previous studies, the 75th percentile of age of all included patients (73 years) was used as a binary cutoff. Then, frailty was classified using the novel aamFI, which constitutes the 5-item mFI with the addition of 1 point for patients ≥73 years. Multivariable logistic regressions were then used to investigate the relationship between aamFI and postoperative outcomes.

RESULTS

Frail patients ≥73 years had a higher incidence of complications compared to frail patients <73 years. There was a strong association between aamFI and complications. An aamFI of ≥3 (reference aamFI of 0) was associated with an increased odds of 30-day mortality (odds ratio [OR] 8.6, 95% CI 5.0-14.8), any complication (OR 3.1, 95% CI 2.9-3.3), deep vein thrombosis (OR 1.5, 95% CI 1.2-1.8), and nonhome discharge (OR 6.1, 95% CI 5.8-6.4; all P < .001).

CONCLUSION

Although frailty negatively influences outcomes following TKA in patients of all ages, chronologically old, frail patients are particularly vulnerable. The aamFI accounts for this and represents a simple, but powerful tool for stratifying risk in patients undergoing primary TKA.

Profiling the Immune Response to Periprosthetic Joint Infection and Non-Infectious Arthroplasty Failure

Arthroplasty failure is a major complication of joint replacement surgery. It can be caused by periprosthetic joint infection (PJI) or non-infectious etiologies, and often requires surgical intervention and (in select scenarios) resection and reimplantation of implanted devices. Fast and accurate diagnosis of PJI and non-infectious arthroplasty failure (NIAF) is critical to direct medical and surgical treatment; differentiation of PJI from NIAF may, however, be unclear in some cases. Traditional culture, nucleic acid amplification tests, metagenomic, and metatranscriptomic techniques for microbial detection have had success in differentiating the two entities, although microbiologically negative apparent PJI remains a challenge. Single host biomarkers or, alternatively, more advanced immune response profiling-based approaches may be applied to differentiate PJI from NIAF, overcoming limitations of microbial-based detection methods and possibly, especially with newer approaches, augmenting them. In this review, current approaches to arthroplasty failure diagnosis are briefly overviewed, followed by a review of host-based approaches for differentiation of PJI from NIAF, including exciting futuristic combinational multi-omics methodologies that may both detect pathogens and assess biological responses, illuminating causes of arthroplasty failure.

First-time revision knee arthroplasty using a hinged prosthesis : temporal trends, indications, and risk factors associated with re-revision using data from the National Joint Registry for 3,855 patients

AIMS

The aim of this study was to identify variables associated with time to revision, demographic details associated with revision indication, and type of prosthesis employed, and to describe the survival of hinge knee arthroplasty (HKA) when used for first-time knee revision surgery and factors that were associated with re-revision.

METHODS

Patient demographic details, BMI, American Society of Anesthesiologists (ASA) grade, indication for revision, surgical approach, surgeon grade, implant type (fixed and rotating), time of revision from primary implantation, and re-revision if undertaken were obtained from the National Joint Registry data for England, Wales, Northern Ireland, and the Isle of Man over an 18-year period (2003 to 2021).

RESULTS

There were 3,855 patient episodes analyzed with a median age of 73 years (interquartile range (IQR) 66 to 80), and the majority were female (n = 2,480, 64.3%). The median time to revision from primary knee arthroplasty was 1,219 days (IQR 579 to 2,422). Younger age (p < 0.001), decreasing ASA grade (p < 0.001), and indications for revision of sepsis (p < 0.001), unexplained pain (p < 0.001), non-polyethylene wear (p < 0.001), and malalignment (p < 0.001) were all associated with an earlier time to revision from primary implantation. The median follow-up was 4.56 years (range 0.00 to 17.52), during which there were 410 re-revisions. The overall unadjusted probability of re-revision for all revision HKAs at one, five, and ten years after surgery were 2.7% (95% confidence interval (CI) 2.2 to 3.3), 10.7% (95% CI 9.6 to 11.9), and 16.2% (95% CI 14.5 to 17.9), respectively. Male sex (p < 0.001), younger age (p < 0.001), revision for septic indications (p < 0.001) or implant fracture (p = 0.010), a fixed hinge (p < 0.001), or surgery performed by a non-consultant grade (p = 0.023) were independently associated with an increased risk of re-revision.

CONCLUSION

There were several factors associated with time to first revision. The re-revision rate was 16.2% at ten years; however, the risk factors associated with an increased risk of re-revision could be used to counsel patients regarding their outcome.Cite this article: Bone Joint J 2023;105-B(1):47-55.

Linkage Between Databases in Joint Arthroplasty and Orthopaedics: The Way Forward?

Each large observational database contains specific data elements. The number of data elements are chosen carefully to cover the essential needs of the database as well as to avoid excessive burden of collection. Frequently, an important study question cannot be answered because one database does not contain some essential data elements. This deficiency may be present because the proposed study is cross-disciplinary, because the study requires more granular information on a specific topic than is practical to collect in a broad-based registry, or because the relevant questions, and hence essential data elements, have changed over time. An obvious way to overcome some such challenges, when one database contains some of the information and another contains the further needed data, is to link different databases. While the prospect of linking databases is appealing, the practicalities of doing so often are daunting. Challenges may be practical (information-technology barriers to crosstalk between the registries), legal, and financial. In the first section of this paper, Dr. Nathanael Heckmann discusses linking large orthopaedic databases, focusing on linking databases with detailed, short-term data to those with longer-term longitudinal data. In the second part of this paper, Nathan Glusenkamp discusses efforts to link the American Joint Replacement Registry (AJRR) to other data sources, an ambition not yet fully realized but one that will bear fruit in the near future.

A Novel Quantitative Evaluation of Bone Formation After Opening Wedge High Tibial Osteotomy Using Tomosynthesis

This study aimed to establish and validate a novel evaluation method using digital tomosynthesis to quantify bone formation in the gap after opening wedge high tibial osteotomy (OW-HTO). We retrospectively analyzed bone formation in the gap in 22 patients who underwent OW-HTO using digital tomosynthesis at 1, 2, 3, 6, 9, and 12 months postoperatively. Bone formation was semi-quantitatively assessed using the modified van Hemert's score and density measurements on digital tomosynthesis images. The gap filling value (GFV) was calculated as the ratio of the intensities of the opening gap and the tibial shaft. In addition, the relationship between the modified van Hemert's score and GFV was evaluated. The reproducibility of GFV had an interclass correlation coefficient (ICC [1,2]) of 0.958 for intraobserver reliability and an ICC (2,1) of 0.975 for interobserver reliability. The GFV increased in a time-dependent manner and was moderately correlated with the modified van Hemert's score (r = 0.630, p < 0.001). The GFV plateaued at 6 months postoperatively. In addition, the GFV was higher in patients with a modified van Hemert's score of 2 than in patients with a modified van Hemert's score of 3 (p = 0.008). The GFVs obtained using digital tomosynthesis can be used to assess postoperative bone formation in the opening gap after OW-HTO with high accuracy and reproducibility.

Development and validation of a nomogram to predict complications in patients undergoing simultaneous bilateral total knee arthroplasty: A retrospective study from two centers

Purpose

Complications were significantly increased 30 days after Simultaneous bilateral total knee arthroplasty (SBTKA). In this study, an individualized nomogram was established and validated to predict the complications within 30 days after SBTKA.

Methods

The general data of 861 patients (training set) who received SBTKA in The Affiliated Hospital of Qingdao University between January 1, 2012 and March 31, 2017 were retrospectively analyzed. All patients were divided into complication group (n = 96) and non-complication group (n = 765) according to the incidence of complications within 30 years after SBTKA. Independent risk factors for postoperative SBTKA complications were identified and screened by binary logistic regression analyses, and then a nomogram prediction model was constructed using R software. The area under curve (AUC), calibration curve, and decision curve analysis (DCA) were selected to evaluate the line-chart. Meanwhile, 396 patients receiving SBTKA in the Third Hospital of Hebei Medical University who met the inclusion and exclusion criteria (test set) were selected to verify the nomogram.

Results

Five independent predictors were identified by binary logistic regression analyses and a nomogram was established. The AUC of this nomogram curve is 0.851 (95% CI: 0.819–0.883) and 0.818 (95% CI: 0.735–0.900) in the training and testing sets, respectively. In the training set and test set, calibration curves show that nomogram prediction results are in good agreement with actual observation results, and DCA shows that nomogram prediction results have good clinical application value.

Conclusion

Older age, lower preoperative hemoglobin level, higher preoperative blood urea nitrogen (BUN) level, longer operation time, ASA grade ≥ III are independent predictors of SBTKA complications within 30 days after surgery. A nomogram containing these five predictors can accurately predict the risk of complications within 30 days after SBTKA.

Does systemic lupus erythematosus impact the peri-operative complication rates following primary total knee arthroplasty? A national inpatient sample-based large-scale study

INTRODUCTION

Consequent to improved life expectancies, there has been a substantial increase in the proportion of patients with systemic lupus erythematosus (SLE) undergoing total knee arthroplasty (TKA) over the past 2 decades. In comparison to the other inflammatory disorders, the complication rates and post-operative outcome in patients with SLE are less clearly understood, owing to the paucity of evidence in the literature.

METHODS

Patients who underwent TKA between 2016 and 2019 were identified (ICD-10CMP code) using the National Inpatient Sample (NIS) database and then classified into one of the two groups, namely those with SLE (ICD-10-CM; code710.0) and those without SLE (NSLE). Demographic details, co-morbidities, details regarding hospital stay, costs incurred, and complications encountered of this patient cohort were analysed and compared between the two groups.

RESULTS

Overall, among 5,58,361 patients undergoing TKA, 2,094 (0.38%) patients had SLE. The SLE group was significantly younger than NSLE population (62.2 ± 9.9 vs 66.7 ± 9.5 years; p < 0.001). The proportion of female and African-American patients was higher in the SLE group (p < 0.001). SLE patients had a significantly longer hospital stay (p < 0.001) and greater hospital-related expenditure (p < 0.001). Among the peri-operative complications, SLE patients had significantly greater risk of developing post-operative anemia (19.2% in SLE vs 15.3% in NSLE; p < 0.001), requiring blood transfusion (2.8% in SLE vs 1.5% in NSLE; p < 0.001), and acquiring peri-prosthetic joint infections (1.9% in SLE vs 1% in NSLE; p < 0.001).

CONCLUSION

The presence of SLE significantly lengthens hospital stay, and augments the health-care-related costs in patients undergoing TKA. The rates of peri-prosthetic infections, post-operative anemia, and need for blood transfusions are significantly greater in SLE patients.

Dually Insured Medicare/Medicaid Patients Undergoing Primary TJA Have More Comorbidities, Higher Complication Rates, and Lower Reimbursements Compared to Privately Insured Patients

BACKGROUND

Dual eligibility status (DES: qualifying for both Medicare and a Medicaid supplement) was recently proposed by the Center for Medicare and Medicaid Services as a socioeconomic qualifier for risk adjustment in primary total joint arthroplasty. However, the profile and outcomes of DES patients have never been compared to privately insured patients.

METHODS

A retrospective case-control study of the Mariner database within the PearlDiver server between 2010 and 2017 was performed. Patients aged 60 to 80 undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) (separately) were stratified based upon payer type: DES versus private payer. A propensity score-matched analysis with nearest neighbor pairing (1:1 ratio) was performed to compare 90-day outcomes and reimbursements.

RESULTS

A total of 315,664 private and 3961 DES THA patients and 670,899 private and 2255 DES TKA patients were identified. DES patients were older and had a greater prevalence of comorbidities (31/36, P < .001). The THA DES matched cohort had greater transfusion rates (6.8% versus 3.9%, P < .001), higher 90-day emergency department visits (22.8% versus 16.3%, P < .001) and readmissions (16.8% versus 9.5%, P < .001), and lower reimbursements ($19,615 versus $13,036, P < .001). The TKA DES matched cohort had more cardiac events (0.4% versus 0.09%, P = .03), emergency department visits (25.2% versus 19.9%, P < .001), readmissions (14.4% versus 11.2%, P = .001), and reoperations (0.85% versus 0.35%, P = .03) CONCLUSION: DES patients have different comorbidity profiles, and even after propensity score matching have a greater risk of complications and are reimbursed less compared to privately insured patients. In the setting of alternative payment models, these differences should be accounted for through risk adjustment.

Pharmacological thromboprophylaxis as a risk factor for early periprosthetic joint infection following primary total joint arthroplasty

Venous thromboembolism (VTE) prophylaxis has been suggested for patients who underwent total join arthroplasty (TJA). However, the morbidity of surgical site complications (SSC) and periprosthetic joint infection (PJI) has not been well evaluated. We aimed to evaluate the impact of VTE prophylaxis on the risk of early postoperative SSC and PJI in a Taiwanese population. We retrospectively reviewed 7511 patients who underwent primary TJA performed by a single surgeon from 2010 through 2019. We evaluated the rates of SSC and PJI in the early postoperative period (30-day, 90-day) as well as 1-year reoperations. Multivariate regression analysis was used to identify possible risk factors associated with SSC and PJI, including age, sex, WHO classification of weight status, smoking, diabetes mellitus (DM), rheumatoid arthritis(RA), Charlson comorbidity index (CCI), history of VTE, presence of varicose veins, total knee or hip arthroplasty procedure, unilateral or bilateral procedure, or receiving VTE prophylaxis or blood transfusion. The overall 90-day rates of SSC and PJI were 1.1% (N = 80) and 0.2% (N = 16). VTE prophylaxis was a risk factor for 90-day readmission for SSC (aOR: 1.753, 95% CI 1.081-2.842), 90-day readmission for PJI (aOR: 3.267, 95% CI 1.026-10.402) and all 90-day PJI events (aOR: 3.222, 95% CI 1.200-8.656). Other risk factors included DM, underweight, obesity, bilateral TJA procedure, younger age, male sex and RA. Pharmacological thromboprophylaxis appears to be a modifiable risk factor for SSC and PJI in the early postoperative period. The increased infection risk should be carefully weighed in patients who received pharmacological VTE prophylaxis.

The Age-Adjusted Modified Frailty Index: An Improved Risk Stratification Tool for Patients Undergoing Primary Total Hip Arthroplasty

BACKGROUND

Frailty and increasing age are well-established risk factors in patients undergoing total hip arthroplasty (THA). However, these variables have only been considered independently. This study assesses the interplay between age and frailty and introduces a novel age-adjusted modified frailty index (aamFI) for more refined risk stratification of THA patients.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried from 2015 to 2019 for patients undergoing primary THA. First, outcomes were compared between chronologically younger and older frail patients. Then, to establish the aamFI, one additional point was added to the previously described mFI-5 for patients aged ≥73 years (the 75th percentile for age in our study population). The association of aamFI with postoperative complications and resource utilization was then analyzed categorically.

RESULTS

A total of 165,957 THA patients were evaluated. Older frail patients had a higher incidence of complications than younger frail patients. Regression analysis demonstrated a strong association between aamFI and complications. For instance, an aamFI of ≥3 (compared to aamFI of 0) was associated with an increased odds of mortality (OR: 22.01, 95% confidence interval [CI] 11.62-41.68), any complication (OR: 3.50, 95% CI 3.23-3.80), deep vein thrombosis (OR: 2.85, 95% CI 2.03-4.01), and nonhome discharge (OR 9.61, 95% CI 9.04-10.21; all P < .001).

CONCLUSION

Chronologically, older patients are impacted more by frailty than younger patients. The aamFI accounts for this and outperforms the mFI-5 in prediction of postoperative complications and resource utilization in patients undergoing primary THA.

Trends in Complications and Outcomes in Patients Aged 65 Years and Younger Undergoing Total Knee Arthroplasty: Data From the American Joint Replacement Registry

The purpose of this study was to identify common complications and the rates of readmission and revision in total knee arthroplasty (TKA) patients younger than 65 years.

Decreased Implant Survival is Associated With Younger Patients Undergoing Total Knee Arthroplasty

Background: Younger patients are undergoing total knee arthroplasty (TKA) at increasing rates and may face multiple revisions during their lifetimes due to mechanical complications or infections. Questions/Purposes: We sought to compare the early complication rates and revision-free implant-survival rates across age groups of patients undergoing TKA, with particular focus on implant survival in younger patients. Methods: We conducted a retrospective analysis of data taken from a national insurance database on patients who underwent primary TKA from 2007 to 2015. Kaplan-Meier curve survival analysis and log rank test were performed to evaluate revision rates in 7 age groups (younger than 40, 40-49, 50-59, 60-69, 70-79, 80-89, and 90 or more years of age). Complication rates were compared to rates in the age 60 to 79 years age groups using multiple logistic regression, controlling for baseline demographics and comorbidities. Results: There were 114,698 patients included in the analysis. Patients in the younger than 40 years, 40 to 49 years, and 50 to 59 years age groups had increased rates of early mechanical complications; 90-day readmission rates were significantly higher in those age groups as well. Revision-free implant survival at 5 years was significantly worse in patients younger than 60 years of age, particularly those less than 40 years, who had a 77% revision-free implant-survival rate at 5 years. Conclusions: Younger patients had a higher risk of early revision after TKA, as well as an increased rate of mechanical complications and readmissions at 90 days. These outcomes suggest more study is needed to better understand these discrepancies and to better guide preoperative counseling for young patients considering TKA.

Antibiotic-free antimicrobial poly (methyl methacrylate) bone cements: A state-of-the-art review

Prosthetic joint infection (PJI) is the most serious complication following total joint arthroplasty, this being because it is associated with, among other things, high morbidity and low quality of life, is difficult to prevent, and is very challenging to treat/manage. The many shortcomings of antibiotic-loaded poly (methyl methacrylate) (PMMA) bone cement (ALBC) as an agent for preventing and treating/ managing PJI are well-known. One is that microorganisms responsible for most PJI cases, such as methicillin-resistant S. aureus, have developed or are developing resistance to gentamicin sulfate, which is the antibiotic in the vast majority of approved ALBC brands. This has led to many research efforts to develop cements that do not contain gentamicin (or, for that matter, any antibiotic) but demonstrate excellent antimicrobial efficacy. There is a sizeable body of literature on these so-called “antibiotic-free antimicrobial” PMMA bone cements (AFAMBCs). The present work is a comprehensive and critical review of this body. In addition to summaries of key trends in results of characterization studies of AFAMBCs, the attractive features and shortcomings of the literature are highlighted. Shortcomings provide motivation for future work, with some ideas being formulation of a new generation of AFAMBCs by, example, adding a nanostructured material and/or an extract from a natural product to the powder and/or liquid of the basis cement, respectively.

Outcomes of Total Knee Arthroplasty in Patients With a Prior Contralateral Above-Knee Amputation: A Retrospective Review of a Nationwide Database

Background

Total knee arthroplasty (TKA) in patients with a prior contralateral above-knee amputation (AKA) is uncommon, with limited literature describing the outcomes. We used a national database to compare the outcomes of primary TKA in above-knee amputees and nonamputees.

Methods

A retrospective review of TKA recipients with prior contralateral AKA was performed using the PearlDiver database from 2010 to Q2 of 2019. Subjects and outcomes were identified using Current Procedural Terminology and International Classification of Diseases, Ninth and Tenth Revisions (ICD-9 and ICD-10). Patients were identified and matched at a 1-to-3 ratio with nonamputee (AKA group = 931; nonamputee group = 2792 patients). Perioperative outcomes and length of stay (LOS) were compared at 90 days, 6 months, 1 year, 3 years, and 5 years after TKA.

Results

The AKA group had a longer LOS (5.19 vs 3.00, P < .001) and higher overall complications rate (33.8% vs 11.8%). At all studied time intervals, the AKA group had higher periprosthetic infections, revisions, mechanical complications, and respiratory failure (P < .001), as well as surgical site infection, pneumonia, and blood transfusion (P < .05).

Conclusion

Our study revealed higher overall complications and longer LOS among TKAs in prior contralateral above-knee amputees. Surgeons should evaluate the risks and benefits of performing a TKA on patients with prior contralateral AKA.

A Coronal Landmark for Tibial Component Positioning With Anatomical Alignment in Total Knee Arthroplasty: A Radiological and Clinical Study

Objective

The purpose of this study was to investigate the value of the lateral point of articular surface of distal tibia (LADT) for anatomical alignment in total knee arthroplasty.

Methods

We reconstructed 148 three-dimensional pre-arthritic tibias and measured the tibial component inclination angle corresponding to the distal landmark of LADT. A retrospective study included 81 TKA recipients divided into the AA group and MA group. Clinical assessments including ROM, HSS, WOMAC, satisfaction for surgery, and radiological assessment were evaluated at one-year follow-up.

Results

The tibial component varus angle corresponding to the distal landmark of LADT in the male and female groups were 3.4 ± 0.3° (2.6~4.2°) and 3.2 ± 0.3° (2.3~4.0°), respectively (P &lt;0.05). Using LADT as the distal landmark for extramedullary tibial cutting guidance, the medial proximal tibia angle (MPTA) of the AA group was 87.0±1.2° (85.0~90.0°), and the AA and MA technique showed no difference in improvement in postoperative knee functional recovery at final follow-up.

Conclusions

This study preliminarily indicated that LADT can be a reliable and economical landmark for coronal plane alignment of the tibial component.

Good subjective outcome and low risk of revision surgery with a novel customized metal implant for focal femoral chondral lesions at a follow-up after a minimum of 5 years

BACKGROUND AND PURPOSE

Patients with focal cartilage lesions experience functional impairment. Results for biological treatments in the middle-aged patient is poor. Previous studies with focal prosthetic inlay resurfacing have shown a higher risk of conversion to total knee replacement at mid-term follow-up. A novel customized implant (Episealer, Episurf, Stockholm, Sweden) has been proposed to improve implant positioning and survival. The primary objective was to assess subjective-, objective function and implant survival at a minimum of five years after surgery.

MATERIALS AND METHODS

The inclusion criteria were patients aged 30-65 years with symptomatic focal chondral defects in the medial femoral condyle, International Cartilage Research Society grade 3 or 4 and failed conservative or surgical treatment. Minimum follow-up of 5 years. Clinical and radiologic assessments were made. Patient-reported outcome measurements at the latest follow-up were compared with the baseline data for the Knee injury and Osteoarthritis Outcome Score (KOOS), the EuroQoL (EQ-5D), the Tegner Activity Scale and a Visual Analog Scale of pain (VAS 0-10).

RESULTS

Ten patients with the mean follow-up period of 75 months (60-86 months, SD 10) were included. Signs of osteoarthritis were seen in one patient (Ahlbäck 1). No cases with revision to knee replacement. VAS for pain and KOOS showed improvements that reached significance for VAS (p ≤ 0.001) and the KOOS subscores Pain (p = 0.01), ADL (p = 0.003), Sport and Recreation (p = 0.024) and Quality of Life (p = 0.003).

CONCLUSION

A good subjective outcome, a low risk of progression to degenerative changes and the need for subsequent surgery were seen at the mid-term follow-up with this customized focal knee-resurfacing implant.

LEVEL OF EVIDENCE

Prospective case series, level 4.

Hospital volume-outcome relationship in total knee arthroplasty: a systematic review and dose-response meta-analysis

PURPOSE

This systematic review and dose-response meta-analysis aimed to investigate the relationship between hospital volume and outcomes for total knee arthroplasty (TKA).

METHODS

MEDLINE, Embase, CENTRAL and CINAHL were searched up to February 2020 for randomised controlled trials and cohort studies that reported TKA performed in hospitals with at least two different volumes and any associated patient-relevant outcomes. The adjusted effect estimates (odds ratios, OR) were pooled using a random-effects, linear dose-response meta-analysis. Heterogeneity was quantified using the I²-statistic. ROBINS-I and the GRADE approach were used to assess the risk of bias and the confidence in the cumulative evidence, respectively.

RESULTS

A total of 68 cohort studies with data from 1985 to 2018 were included. The risk of bias for all outcomes ranged from moderate to critical. Higher hospital volume may be associated with a lower rate of early revision ≤ 12 months (narrative synthesis of k = 7 studies, n = 301,378 patients) and is likely associated with lower mortality ≤ 3 months (OR = 0.91 per additional 50 TKAs/year, 95% confidence interval [0.87-0.95], k = 9, n = 2,638,996, I² = 51%) and readmissions ≤ 3 months (OR = 0.98 [0.97-0.99], k = 3, n = 830,381, I² = 44%). Hospital volume may not be associated with the rates of deep infections within 1-4 years, late revision (1-10 years) or adverse events ≤ 3 months. The confidence in the cumulative evidence was moderate for mortality and readmission rates; low for early revision rates; and very low for deep infection, late revision and adverse event rates.

CONCLUSION

An inverse volume-outcome relationship probably exists for some TKA outcomes, including mortality and readmissions, and may exist for early revisions. Small reductions in unfavourable outcomes may be clinically relevant at the population level, supporting centralisation of TKA to high-volume hospitals.

LEVEL OF EVIDENCE

III.

REGISTRATION NUMBER

The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO CRD42019131209 available at: https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=131209 ).

A Matched Comparison of the Long-Term Outcomes of Cemented and Cementless Total Knee Replacements: An Analysis from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man

BACKGROUND

Total knee replacements (TKRs) can be implanted with or without the use of cement. It is currently uncertain how cemented and cementless TKRs compare overall and in different age groups of the population in the long term.

METHODS

The National Joint Registry collects information on knee replacements inserted in England, Wales, Northern Ireland, and the Isle of Man and was linked for multiple confounders to the National Health Service Hospital Episode Statistics database. With use of propensity score matching techniques, 44,954 cemented and cementless TKRs were compared. Regression models were used to compare the outcomes of revision, reoperation, and mortality both overall and in different age strata.

RESULTS

The 10-year implant survival rate with revision as the end point for cemented and cementless TKRs was 96.0% and 95.5%, respectively (hazard ratio [HR] = 1.14; p = 0.01). The 10-year survival rate with reoperation as the end point was 82.7% and 81.4%, respectively (HR = 1.08; p = 0.001). The rate of revision for pain was higher for cementless TKRs (0.5% [cemented] compared with 0.7% [cementless]; p = 0.002), but the rate of revision for infection was lower (0.7% [cemented] compared with 0.5% [cementless]; p = 0.003). No significant interactions with age existed for the outcomes of revision (p = 0.24), reoperation (p = 0.30), or mortality (p = 0.58).

CONCLUSIONS

We found that matched cemented and cementless TKRs both have 10-year implant survival rates of >95%. Cementless TKRs had a higher revision rate (absolute difference, 0.5%) and reoperation rate (absolute difference, 1.3%). The rate of revision for infection was lower in the cementless group, although the rate of revision for pain was higher. Age did not significantly affect the relative performances.

LEVEL OF EVIDENCE

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

Risk factors of postoperative complications following total knee arthroplasty in Korea: A nationwide retrospective cohort study

BACKGROUND

The number of patients undergoing total knee arthroplasty (TKA) is gradually increasing and there is also increase in postoperative complications. The patient's demographic, socio-economic factors, hospital and clinical factors are all factors that can influence postoperative complications. The purpose of this study was to determine the risk factors associated with complications following TKA in a large national cohort.

METHODS

Among patients diagnosed with primary knee arthrosis, a total of 560,954 patients older than 50 years who underwent TKA from January 1, 2005 to December 31, 2018 were included in the study. The risk of postoperative complications (surgical site infection, sepsis, cardiovascular complications, respiratory complications, pulmonary embolism, stroke, acute renal failure, periprosthetic joint infection, and periprosthetic fracture) were assessed with eight independent variables: gender, age, place of residence, household income, hospital bed size, procedure type (unilateral or bilateral, primary or revision TKA), length of stay (LOS), use of transfusion. Multivariable Cox Proportional Hazard model analysis was used. The significant predictors for complications (P < .05) were as follows.

RESULTS

Surgical site infection: male, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Sepsis: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Cardiovascular complications: male, age, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Respiratory complications: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Pulmonary embolism: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Stroke: male, age, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Acute renal failure: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Periprosthetic joint infection: male, household income, procedure type (bilateral, revision), LOS (≥35 days), transfusion. Periprosthetic fracture: male, procedure type (bilateral, revision), LOS (≥35 days), transfusion.

CONCLUSION

In summary, male, procedure type (bilateral, revision), LOS (≥35 days), and use of transfusion were shown to be risk factors of postoperative complications following TKA.

Successful Treatment of Femoral Chondral Lesions with a Novel Customized Metal Implant at Midterm Follow-Up

BACKGROUND

Full-depth cartilage lesions do not heal spontaneously and may progress to osteoarthritis (OA). Treatment for these lesions is warranted when symptomatic. At younger age, biological treatment remains the gold standard, but treatment in the middle-aged patient remains a clinical challenge and focal metal implants have been proposed. We aim to present the subjective outcome at 2 years and the risk of reoperation for any reason at midterm after surgery with a novel customized implant for focal femoral chondral lesions in the knee.

METHODS

In a prospective cohort study, 30 patients were included between January 2013 and December 2017 at 9 different clinics in Sweden. The primary outcome was subjective outcome measurements (Visual Analogue Scale [VAS], EuroQoL [EQ5D], Knee injury and Osteoarthritis Outcome Score [KOOS]) at a minimum of 2 years. The secondary outcome was reoperations for any reason during the follow-up period until December 2019 (mean of 55 months) studied retrospectively by analyzing medical records.

RESULTS

The VAS, EQ5D, and all the KOOS subscales showed significant improvements from preoperatively to the 2-year follow-up. The VAS showed the greatest improvement at the early (3 months) postoperative stage (P < 0.001). Five (7%) patients underwent reoperations and one of these was revised to hemiarthroplasty due to OA progression. No implant loosening was detected in any of the cases.

CONCLUSIONS

This customized resurfacing metal implant showed good safety and patient satisfaction. The risk of OA progression and implant loosening is low. Subjective function and pain improved significantly.