Total knee arthroplasty in patients with juvenile idiopathic arthritis

Robotic-assisted total knee arthroplasty is associated with the use of thinner polyethylene liners compared to navigation-guided and manual techniques

PURPOSE

The purpose of this study was to examine the effects of intraoperative technology use on the rate of using polyethylene liners 15 mm or greater during primary total knee arthroplasty (TKA).

METHODS

There were 103,295 implants from 16,386 primary unilateral TKAs performed on 14,253 patients at a single institution between 1 January 2018, and 30 June 2022, included in the current study. Robotic assistance and navigation guidance were used in 1274 (8%) and 8345 (51%) procedures, respectively. The remaining 6767 TKAs (41%) were performed manually. Polyethylene liners were manually identified and further subcategorised by implant thickness. Patients who underwent robotic-assisted TKA were younger (p < 0.001) and more likely to be male (p < 0.001) compared to patients who underwent navigation-guided or manual TKAs.

RESULTS

Average polyethylene liner thickness was similar between groups (10.5 ± 1.5 mm for robotic-assisted TKAs, 10.9 ± 1.8 mm for navigation-guided TKAs and 10.8 ± 1.8 mm for manual TKAs). The proportions of polyethylene liners 15 mm or greater used were 4.9%, 3.8% and 1.9% for navigation-guided, manual and robotic-assisted procedures, respectively (p < 0.001). Multivariate regression analyses demonstrated that navigation-guided (odds ratio [OR]: 2.6, 95% confidence Interval [CI]: [1.75-4.07], p < 0.001) and manual (OR: 2.0, 95% CI: [1.34-3.20], p = 0.001) procedures were associated with an increased use of polyethylene liners 15 mm or greater.

CONCLUSION

Robotic-assisted TKA was associated with a lower proportion of polyethylene liners 15 mm or greater used compared to navigation-guided and manual TKA. These findings suggest that robotic assistance can reduce human error via a more precise cutting system, limit over-resection of the tibia and flexion-extension gap mismatch and ultimately allow for more appropriately sized implants.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

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.

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.

Mid-term clinical outcomes of a posterior stabilized total knee prosthesis for Japanese patients: A minimum follow-up of 5 years

BACKGROUND

A high-flexion posterior-stabilized total knee prosthesis has been developed for the Asian population. The component design was based on computed tomography images of Japanese osteoarthritic knees. The femoral component is composed of zirconia ceramics, which exhibit low friction and high durability. The present study aimed to evaluate the mid-term clinical outcomes of this implant.

METHODS

This study included 334 knees of 210 patients who underwent primary total knee arthroplasty with this implant at our hospital between October 2010 and December 2014. The patients comprised 28 men and 172 women with an average age of 73 years. The average follow-up period was 5.9 years, and the follow-up rate was 71.1%. Clinical outcomes were assessed using the Knee Society scoring system, 2011 Knee Society questionnaire, and Knee Injury and Osteoarthritis Outcome Score. Kaplan-Meier survivorship analysis was performed to determine the cumulative prosthesis survival rate.

RESULTS

In terms of clinical outcomes at the final follow-up, the average ranges of motion were -2.0 in extension and 126.7 in flexion. The Knee Society knee and function scores were 94.2% and 72.6%, respectively. With revision surgery or radiographic failure for any reason as the endpoint, the survival rates at 5 and 9 years were 98.2% and 95.5%, respectively. The most common reason for revision surgery or radiological failure was aseptic loosening.

CONCLUSIONS

Despite several revision cases mainly due to aseptic loosening, the present study found that this new high-flexion posterior-stabilized total knee arthroplasty prosthesis design showed comparable results for Asian populations with other PS prosthesis.

LEVELS OF EVIDENCE

Level Ⅱ (Prospective cohort study).

Case Report of Successful Bilateral Total Knee Arthroplasty: 46 Years and Still Going

CASE

A 63-year-old woman with 46-year-old bilateral cemented total knee arthroplasty (TKA) presented to our clinic for routine evaluation. She was diagnosed with idiopathic juvenile arthritis at the age of 17. Radiographically she had well-fixed implants bilaterally without bone-cement lucency. She is ambulating without a limp, pain, or an assistance aid.

CONCLUSION

We report TKA implants that lasted for 46 years. Literature suggests that most TKAs can last up to 20 to 25 years, but there are few reports that document implant survivorship longer than that. Our report demonstrates the possibility of long survivorship in TKA implants.

Surgical Treatment of Juvenile Idiopathic Arthritis in the Era of Novel Drug Therapies

Juvenile idiopathic arthritis is the most common chronic rheumatic disease encountered in children under the age of sixteen and causes significant impairments in daily life. Over the last two decades, the introduction of new drug treatments (including disease-modifying antirheumatic drugs and biologics) has changed the course of this disease, thus reducing the indication for surgery. However, some patients fail to respond to drug therapy and thus require personalized surgical management, e.g., the local reduction of joint effusion or a synovial pannus (via intra-articular corticosteroid injections, synovectomy, or soft tissue release), and management of the sequelae of arthritis (such as growth disorders and joint degeneration). Here, we provide an overview of the surgical indications and outcomes of the following interventions: intra-articular corticosteroid injections, synovectomy, soft tissue release, surgery for growth disorders, and arthroplasty.

Tumors Constitute a Majority of Total Knee Arthroplasty in Patients <21 Years Old: A United States Nationwide Analysis

BACKGROUND

Total knee arthroplasty (TKA) is rarely performed in patients under 21 years old, but the frequency of utilization of TKA in this population in the United States is not known. The purpose of this study was to evaluate trends in the use of TKA in patients <21 in the United States. Additionally, we aimed to determine the characteristics of these patients and the hospitals in which this procedure is performed.

METHODS

We retrospectively reviewed the Kids' Inpatient Database, a national weighted sample of all inpatient hospital admissions in the United States in patients <21 years of age. We used International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 codes to identify patients undergoing TKA from 2000 to 2019 and determine a primary diagnosis. Descriptive statistics were calculated using the appropriate sample weights.

RESULTS

The total weighted number of TKAs performed in patients <21 years from 2000 to 2019 was 1,535. There were 70.9% of TKAs performed for a primary diagnosis of tumor, and the use of TKA for malignant tumors has increased. In contrast, the use of TKA for inflammatory arthritis/juvenile idiopathic arthritis decreased significantly over the study period. The majority of TKAs were performed in urban teaching hospitals with a large bed size.

CONCLUSION

Approximately 1,535 TKAs have been performed in patients <21 years from 2000 to 2019 in the United States. The majority of these procedures were performed for reconstruction after resection of a malignant tumor. The rate of TKA for inflammatory arthritis/juvenile idiopathic arthritis has decreased over the past two decades.

The Effect of Working Time and Application Technique on Cement Penetration into a Tibial Model

Background

Aseptic loosening of the cemented tibial component is a source of failure in total knee arthroplasty. This study examined common techniques for cement application by quantifying depth and volume of penetration into tibia models.

Material and methods

Thirty-six composite tibia models were cemented with a tibial component using 3 application techniques (gun, osteotome, and layered) with either early or late cement working time. Computed tomography and 3D-modeling were used to quantify volume and depth of penetration. Statistical analysis was conducted with analysis of variance with Bonferroni correction and Student’s t-test.

Results

No difference was found in overall volume of penetration between early and late cement application (P = .16). Beneath the baseplate, the layered technique had significantly less penetration and averaged less than 3 mm with early and late cement. The gun technique had the greatest depth of penetration with early cement and averaged greater than 3 mm in all zones regardless of cement working time. The osteotome technique achieved significantly greater depth of penetration around the keel with early and late cement, P < .01.

Conclusions

Using a cement gun ensures adequate penetration beneath the baseplate regardless of cement working time while the osteotome technique is effective to increase penetration around the implant keel. According to our study, applying cement early in its working time may not increase volume of penetration. This study raises concern regarding adequate cement penetration using the layered technique for cementing the tibial component in total knee arthroplasty, and future research is warranted.

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.

Two-Staged Total Knee Arthroplasty in Juvenile Rheumatoid Arthritis with Severe Flexion Deformity: A Case Report

CASE

Juvenile rheumatoid arthritis (JRA) is associated with severe flexion contracture of the knees disabling a patient's ability to walk. Although various treatment modalities are available in the literature, we report a 2-stage procedure in a case of a 22-year-old female JRA patient with bilateral severe flexion deformity of the knee: stage 1-correction of the flexion contracture deformity by ring fixators and stage 2-total knee arthroplasty (TKA) for arthritis. To the best of our knowledge, no such approach has been reported previously.

CONCLUSIONS

An Ilizarov ring fixator is a safe technique for gradual correction of a severe flexion deformity. Subsequent TKA can be performed as a standard procedure.

Good result for twelve years after bilateral hip and knee arthroplasties for ankylosis with juvenile idiopathic arthritis: a case report

Juvenile idiopathic arthritis (JIA) can lead to joint deformity and bone destruction, which can cause gait disturbances. To the best of our knowledge, there are no case reports with over 10 years of follow-up on quadruple joint arthroplasties (QJA) for bilateral hip and knee ankylosis associated with JIA. We present the case of a 29-year-old woman with JIA. The patient suffered from bilateral ankylosis of the hips and knees and developed a swing gait requiring double crutches. We performed staged QJA with careful attention to postoperative rehabilitation and her physical features, which included excessive pelvic anteversion, poor bone quality, and short statue of bones. Twelve years after surgery, the patient was able to walk without any support and showed good clinical functional scores. In addition, no radiological loosening following QJA was observed. We hereby introduce a surgical strategy for total hip arthroplasty for excessive pelvic anteversion, which involves two methods to calculate pelvic tilt on a pelvic anteroposterior radiograph. These methods were able to approximately predict postoperative pelvic changes.

Early Joint Replacement in Juvenile Idiopathic Arthritis: Trend Over Time and Factors Influencing Implant Survival

OBJECTIVE

To describe early prosthesis implantations in a cohort of patients with juvenile idiopathic arthritis (JIA) followed in a tertiary referral hospital and to analyze possible factors influencing implant survival.

METHODS

This was a retrospective cohort study. Charts of all patients with JIA who underwent total joint replacement at Gaetano Pini Hospital, Milan, Italy from January 1992 to June 2019 were retrieved, and relevant data were analyzed.

RESULTS

Eighty-five patients met the inclusion criteria for this study, with a median follow-up period of 17.2 years. The median age at first prosthesis was 22.7 years. The total number of replaced joints was 198 over a period of 27 years. The hip was the most frequently replaced joint, accounting for almost two-thirds of the total number of implants; the other one-third refers mostly to knee implants. Polyarticular JIA and systemic JIA were the most represented JIA categories in the study cohort. A significant upward trend of the age at arthroplasty and of disease duration before arthroplasty over decades was found. The rates of implant survival at 5, 10, and 15 years were comparable (from 84% to 89%); 50% of implants lasted ≥20 years.

CONCLUSION

We reported retrospective data on early joint replacement in a cohort of patients with JIA. We observed a progressive and significant upward trend of both age at arthroplasty and disease duration before the first arthroplasty over time. The JIA category, year of implant, and presence of complications significantly affected implant survivorship.

General Principles of the Surgical Management of Juvenile Inflammatory Arthritis

Surgical management of Juvenile Inflammatory Arthritis (JIA) presents many challenges for the patient, healthcare team and especially the orthopedic surgeon. Collaborative care efforts must be endorsed early on in order to facilitate maximal postoperative functional ability. Developmental levels, both physically and emotionally must be established preoperatively. It is important to determine bone age and growth plate closure to establish the best surgical intervention and avoid leg-length discrepancies later in life. Emotional maturity may impede the ability of the patient to manage pain or follow directions throughout the recuperative process. Surgical challenges require a team approach that includes rheumatologists who can manage disease modifying agents and the effects of discontinuing medications or planning surgery around dosing regimens in order to decrease immunosuppression. Managing multiple joint issues will require an expert team of occupational and physical therapists to prepare adaptive devices and rehabilitate patients who have significant functional limitations and decreased muscular strength. Because of an anticipated longer and more difficult recovery for JIA patients, case managers must engage in support systems and plan for postoperative care prior to surgery. Implant specific devices need to accommodate small bone structure, bone loss and complex deformities along with diaphyseal or epiphyseal dysplasia. Neurologic assessments will avoid cervical spine compromise during anesthesia administration. Bilateral procedures in the lower extremities should be considered whenever flexion contractures are present and should take place prior to upper extremity joint replacements. Restoring function to the hand and wrist takes priority over elbow and shoulder replacement, respectively. The key factors of appropriate surgical management in JIA patients are to decrease pain, restore function and avoid loss of ambulation at a young age. Extensive preoperative planning and communication with the patient, support system and healthcare team are warranted to address the complexities in this patient population.

Juvenile idiopathic arthritis is associated with higher healthcare utilization after total knee or hip replacement

Objective: To assess whether juvenile idiopathic arthritis (JIA) is associated with healthcare utilization and in-hospital complications after total hip or knee arthroplasty (THA/TKA). Method: We used the 1998-2014 US National Inpatient Sample. We performed multivariable-adjusted logistic regression, adjusted for age, race/ethnicity, gender, income, Deyo-Charlson comorbidity index, insurance payer, and the underlying diagnosis. Results: Of the 4 116 485 THAs and 8 127 282 TKAs, 1882 people with JIA had THAs (0.02%) and 1388 had TKAs (0.01%). Compared to people without JIA, people with JIA post-THA and post-TKA had higher odds ratio [OR (95% confidence interval), respectively] of total hospital charges above the median [1.30 (1.05, 1.60) and 1.37 (1.08, 1.74)], length of hospital stay > 3 days [1.64 (1.27, 2.12) and 1.44 (1.07, 1.93)], and discharge to non-home settings [1.37 (1.07, 1.76)] post-THA, but not post-TKA [1.02 (0.77, 1.36)]. People with JIA also had higher OR of transfusion post-TKA [1.92 (1.44, 2.55)], but not post-THA [1.00 (0.77, 1.30)]. Sensitivity analyses that adjusted for hospital characteristics confirmed the main study findings with minimal or no attenuation of OR. Conclusions: People with JIA utilized more healthcare services post-THA/TKA and were more likely to receive transfusions post-TKA. Interventions to reduce the risk of higher resource utilization are needed in people with JIA.

Causes of Revision in Young Patients Undergoing Total Hip Arthroplasty

BACKGROUND

The purpose of this study was to identify reasons for revision of total hip arthroplasty (THA) in patients who underwent primary THA at or before the age of 35 years. We hypothesized that the reasons for revision in younger patients would be different from the general older population of patients undergoing THA because of the differences in diagnoses, complexity of deformities, and differences in activity level.

METHODS

Data for 108 hips in 82 patients who underwent primary THA at our institution before the age of 35 years from 1982-2007 and subsequently underwent revision THA were reviewed. Operative reports and clinic notes were reviewed to determine baseline characteristics, reason for revision, timing of revision, and components revised.

RESULTS

The mean age at index surgery was 25.4 years, and mean time from index to revision surgery was 10.1 years. The most common preoperative diagnoses included avascular necrosis, juvenile idiopathic arthritis, developmental dysplasia of the hip, and posttraumatic arthritis. The most common reasons for revision were acetabular loosening (30.1%), femoral loosening (23.7%), and polyethylene wear (24.7%). 8.3% of patients underwent primary THA with highly cross-linked polyethylene, while the remainder of the patients underwent THA when conventional polyethylene was used. There was no statistically significant association between which component(s) were revised and initial fixation (ie cemented or uncemented prosthesis) (P = .26).

CONCLUSION

Causes of revision in this population appear to differ from the general THA population. In young patients, acetabular loosening, femur loosening, and polyethylene wear were the most common causes of revision. Instability and infection were less common compared with literature reports of causes of revision in older patients. Findings in this study may be useful in counseling young patients undergoing THA, though results were likely influenced by the use of conventional rather than highly cross-linked polyethylene in this cohort.

Resurfacing hemiarthroplasty of the shoulder for patients with juvenile idiopathic arthritis

BACKGROUND

This study reports the outcome of resurfacing hemiarthroplasty (RHA) in a cohort of patients with juvenile idiopathic arthritis (JIA) affecting the shoulder joint METHODS: Fourteen uncemented RHA procedures were performed for 11 consecutive patients who required surgery because of JIA. Mean age at surgery was 36.4 years. Mean clinical follow-up was 10.4 years (range, 5.8-13.9 years). A significant humeral head defect (up to 40% surface area) was found in 5 shoulders and filled with autograft from the distal clavicle or femoral head allograft.

RESULTS

At latest follow-up, no patient required revision. There was excellent relief from pain. The mean Oxford Shoulder Score and Constant-Murley Score improved significantly. No shoulder had a poor outcome, and 6 had a very good or excellent outcome. Worse outcome was associated with an intraoperative finding of significant humeral head erosion. Two shoulders required early arthroscopic subacromial decompression, but there were no other reoperations. There were no instances of radiographic implant loosening or proximal migration. Painless glenoid erosion was seen in 5 shoulders but was not associated with worse outcome.

CONCLUSIONS

The midterm results of RHA for JIA are at least comparable to those for stemmed hemiarthroplasty, with the added benefit of bone conservation.

In-vivo kinematics of high-flex posterior-stabilized total knee prosthesis designed for Asian populations

PURPOSE

The purpose of this study was to determine in-vivo kinematics of our developed posterior-stabilized (PS) total knee prosthesis for Asian populations in comparison with a popular high-flexion PS prosthesis.

METHODS

We analyzed 62 osteoarthritic knees: 31 knees with the new PS prosthesis (group A) and 31 knees with a popular high-flexion PS prosthesis (group B). Radiographic knee images were taken during standing, lunge, and kneeling activities. The three-dimensional position and orientation of the implant components were determined using model-based shape matching techniques.

RESULTS

Group A showed slightly greater implant flexion angles compared with knees with conventional prosthesis at maximum lunge (average: 119 vs. 110°, p = 0.001), and at maximum kneeling (121 vs. 114°, p = 0.004), although the range of motion was not significantly different. The femoral centre positions were more posterior in group A at standing, at 90° lunge, at maximum lunge (-9 and -7 mm, p = 0.004), at 90° kneeling, and at maximum kneeling (-9 vs. -7 mm, p = 0.016), and posterior translations of the femoral center were greater at 90° knee flexion postures. The femoral centre positions had a strong negative correlation with implant flexion angles at maximum lunge in group B (r = -0.893, p < 0.001), but not in group A (p = 0.242).

CONCLUSIONS

The new PS prosthesis designed for Asian knee morphology achieved flexion angles and range of motion at least comparable to that of conventional high-flexion PS prosthesis. The femoral roll-back pattern, however, is different from a conventional knee, reflecting the post/cam design.

Treatment of Secondary Osteonecrosis of the Knee With Local Debridement and Osteoprogenitor Cell Grafting

Secondary osteonecrosis of the knee (SOK) affects young individuals with chronic diseases and corticosteroid use. We report a series of young patients in whom the osteonecrotic lesion was openly debrided, and concentrated bone marrow osteoprogenitor cells (OPCs) harvested from the iliac crest were placed in the defect. Twelve patients (fourteen knees) have undergone debridement and grafting of distal femoral osteonecrotic lesions. Age at surgery averaged 23 years. Follow-up averaged 5 years. None of the patients have undergone further surgery, or were taking medications for ipsilateral knee pain. Knee Society Score and Knee Function Score averaged 87 and 85 respectively. The technique of open debridement and osteoprogenitor cell grafting for SOK is relatively simple, efficacious, has low morbidity, and does not preclude future interventions.

Survivorship of hip and knee implants in pediatric and young adult populations: analysis of registry and published data

BACKGROUND

One of the least researched areas in orthopaedic pediatrics is the safety and effectiveness of joint replacement, in part because it is uncommon and is undertaken for a wide range of conditions not common for adult joint replacement. This study used data from the AOANJRR (Australian Orthopaedic Association National Joint Replacement Registry) to analyze the use of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the pediatric population and to provide preliminary data on the outcome of these procedures.

METHODS

The AOANJRR, which is part of the ICOR (International Consortium of Orthopaedic Registries), provided information on pediatric procedures reported to the registry by hospitals undertaking arthroplasty procedures in Australia. All THA and TKA procedures reported to the registry from 1999 to 2012 were included. The cumulative percent revision and the hazard ratio from Cox proportional-hazards models were used for analysis. All tests were two-tailed, with a 5% level of significance. Additionally, an overview of the literature is presented to provide a point of reference.

RESULTS

Primary conventional THA was performed in 297 patients twenty years of age or younger; the cumulative percent revision at five years was 4.5%. Primary conventional THA was performed in 975 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 5.4%. Primary THA was performed in 105 patients twenty years of age or younger; the cumulative percent revision at five years was 4.6%. Primary TKA was performed in 159 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 10.3%.

CONCLUSIONS

Compared with older adults, pediatric patients and young adults undergoing THA and TKA have very different diagnoses, including a high prevalence of tumor. Although the reported rate of revision surgery is currently similar to that for older patients, the number of reported procedures and the follow-up period remain limited. It is important for registries to continue to collect and analyze data relevant to this cohort and to coordinate these activities in order to better understand the safety and effectiveness of joint arthroplasty in the pediatric population.

What design and material factors impact the wear and corrosion performance in total elbow arthroplasties?

The survivorship of total elbow arthroplasties is lower than surgeons and patients would like it to be, especially in patients with posttraumatic arthritis of the elbow. To improve durability, it is important to understand the failure modes of existing implants. Total elbow arthroplasties were designed primarily for low-demand rheumatoid patients. As surgical indications have extended to more active patient populations, the mechanical performance of current designs must meet an increased mechanical burden. Evaluating the degree to which they do this will guide conclusions about which contemporary devices might still meet the need and, as importantly, what design and material changes might be needed to improve performance. WHERE ARE WE NOW?: The reasons for failures of total elbow arthroplasties include infection, loosening, polyethylene wear, locking mechanism failure, periprosthetic fracture, implant fracture, and instability. Implant design factors that have influenced wear include implant constraint, material, coatings, and metal backing. Surgical factors associated with increased wear and subsequent total elbow arthroplasty failure include soft tissue balancing and restoration of alignment and implant positioning. WHERE DO WE NEED TO GO?: A clear need exists for improving the performance of total elbow arthroplasty. Many of the failures that have limited the survivorship of elbow arthroplasties thus far are mechanical in nature with wear-related problems a dominating influence. Much of what we know about the results of total elbow arthroplasty is from small studies frequently involving the designer of the implant. The establishment of total elbow arthroplasty registries coupled with the increasing regulatory burden of postmarket surveillance would lead to a better understanding of the complications and survivorship of elbow arthroplasties. Another primary goal must be to achieve a better understanding of the biomechanics of the normal elbow and how the mechanics are altered after the insertion of elbow arthroplasty components. HOW DO WE GET THERE?: Improving the performance and survivorship of total elbow arthroplasty will require the integration of clinical and implant performance data gained through the establishment of registries with a concerted basic science effort to better understand the functional loads across the joint and to incorporate these loads into experimental and computational models to allow assessment of design and material changes intended to improve durability.

Surgical management of the juvenile idiopathic arthritis patient with multiple joint involvement

Juvenile idiopathic arthritis (JIA) is recognized as a heterogenous group of disorders in which the common factor is persistent arthritis in at least 1 joint occurring before the age of 16 years. Although conservative management with nonsteroidal anti-inflammatory drugs and disease-modifying antirheumatic drugs can be effective, approximately 10% of JIA patients have end-stage degenerative changes requiring total hip arthroplasties (THAs) and total knee arthroplasties (TKAs). This article discusses the overall epidemiology, coordination of care, and medical and surgical management of JIA patients undergoing THA and TKA.

Causes of failure after total knee arthroplasty in osteoarthritis patients 55 years of age or younger

Purpose

To identify the modes of failure after total knee arthroplasty (TKA) in patients >55 years of age and to compare with those >55 years of age in patients who underwent revision TKA.

Materials and Methods

We retrospectively reviewed 256 revision TKAs among patients who underwent TKA for knee osteoarthritis between January 1992 and December 2012. The causes of TKA failure were analyzed and compared between the groups.

Results

Thirty-one revision TKAs were performed in patients ≤55 years of age at the time of primary TKA, whereas 225 cases were in those >55 years of age at primary TKA. In the ≤55 years of age group, the most common cause of TKA failure was polyethylene wear (45%) followed by infection (26%) and loosening (17%). The interval from primary TKA to revision was 8.6 years (range, 1 to 17 years). There were relatively lower infection rate and higher loosening rate in patients ≤55 years of age, but the difference was not statistically significant.

Conclusions

The main causes of failure after TKA in patients ≤55 years of age were polyethylene wear, infection and loosening, and there was no significant difference in the modes of failure after TKA between the two groups.