Treatment Options for End-Stage Hip Disease in Adolescents: To Replace, Fuse, or Reconstruct?

Total hip arthroplasty in adolescents: a systematic review and meta-analysis

PURPOSE

Total hip arthroplasty (THA) has demonstrated excellent results in elderly patients, however, the indications, outcomes, and long-term results in adolescent patients are less understood. This study aims to assess the outcomes of THA in patients under 21, providing insights for clinical decision-making in this exceptional population.

METHODS

A systematic review in PubMed, Ovid MEDLINE, and Embase database was performed. We included studies reporting clinical, radiological, and functional outcomes of THA in patients younger than 21 years, for any cause, with a with a minimum follow-up of one year. The ten year survivorship estimate was pooled using a meta-analysis methodology and each study was weighted according to its standard error, calculated from published confidence intervals.

RESULTS

We included 25 studies involving 1166 hips. Median age was 17 years old, 60% were females, and the average follow-up was 8.1 years. Juvenile inflammatory arthritis was the main indication for total hip arthroplasty (THA). The all-cause revision rate was 14.4% and aseptic loosening was the most common cause. Only eight studies reported ten year survival rates and form the pooled analysis an 84.91% survival rate (95% CI 70.56 - 99.27) was obtained. An average score of 88.08 in the Harris Hip Score (HHS) was observed. We found a 3.43% complication rate.

CONCLUSIONS

Hip arthroplasty is an acceptable option for adolescents with end-stage arthritis. However, the altered hip anatomy, the elevated revision rate, and the long-term implant survival must be considered before performing a THA in adolescent patients.

Total Hip Arthroplasty in the Ultrayoung

Background

Total hip arthroplasty (THA) procedures provide a surgical option for "ultrayoung" patients ≤30 years old with end-stage hip arthropathy. This has historically been coupled with concerns over early component failure and challenging surgical technique leading to increased risk of overall morbidity. The purpose of this study is to better elucidate the poorly defined indications and outcomes for THA in ultrayoung patients with end-stage hip disease.

Methods

A total of 40 THAs in 35 patients ≤30 years old performed at our institution from 2009 to 2016 were retrospectively followed for an average of 2 years (median 11 months, interquartile range 1-31.25). Primary outcome measure was THA revision. Patient demographics were compared against outcomes. The effects on revision rate of hip joint pathology and type of bearing surface were investigated. T-test, chi-square test, and bivariate correlation were performed to determine statistical significance (P < .05). Machine learning was used to determine the normalized important factor leading to THA revision.

Results

Fifteen male and 25 female patients were included. Median patient age was 23 (interquartile range 19-27) years, with an average body mass index of 27.0 ± 7.9. A majority of THAs were indicated for osteonecrosis (32) and bearing surface type was predominantly metal-on-highly cross-linked polyethylene (36). The overall revision rate was 7.5%, without a correlation between revision and demographic characteristics. Revision surgery was significantly correlated with bearing surface type (P = .028). Important factors for revision were age (100%), bearing surface type (84.7%), and body mass index (52.1%).

Conclusions

In patients ≤30 years old, THAs performed with the use of modern implants and surgical methods show satisfactory survivorship and functional outcomes with short-term follow-up.

MiR-362-5p inhibits cartilage repair in osteoarthritis via targeting plexin B1

BACKGROUND AND OBJECTIVES

Chondrogenesis of bone marrow mesenchymal stem cells (BMSCs) exerts great function during the pathogenesis of osteoarthritis (OA). Studies have reported the association of plexin B1 (PLXNB1) with OA pathogenesis. In this study, the upstream mechanism and function of PLXNB1 in this disease were explored.

METHODS

Flow cytometry was applied to test BMSC characterization. Chondrogenic differentiation of BMSCs was evaluated by Alcian blue staining. The expression of PLXNB1, miR-362-5p, miR-501-5p, miR-1827, miR-500-5p was measured using RT-qPCR analysis. The protein levels of PLXNB1, Aggrecan, and Silent information regulator factor 2-related enzyme 1 (SIRT1) were determined by western blotting. Binding relationship between miR-362-5p and PLXNB1 was confirmed using bioinformatics analysis and luciferase reporter assay. The in vivo model of OA was established in Sprague-Dawley rats which received medial meniscus instability surgery. For histopathological examination, cartilage tissues in the knee joint of rats were stained with hematoxylin and eosin. Micro-CT analysis was employed to observe the changes of morphometric indices including average trabecular separation, average trabecular thickness, and bone volume fraction.

RESULTS

BMSCs were identified to possess the characteristics of mesenchymal stem cells. PLXNB1 was observed to be highly expressed during chondrogenic differentiation of BMSCs and PLXNB1 overexpression promoted BMSC chondrogenic differentiation. Mechanically, PLXNB1 was targeted by miR-362-5p. In rescue assays, miR-362-5p reversed the effects of PLXNB1 on chondrogenic differentiation of BMSCs. In the in vivo experiments, upregulated PLXNB1 expression alleviated joint injury of OA rats. Additionally, overexpressed miR-362-5p and downregulated PLXNB1 expression levels were detected in OA rats.

CONCLUSION

MiR-362-5p promotes OA progression by suppressing PLXNB1.

MiR-145-5p restrains chondrogenic differentiation of synovium-derived mesenchymal stem cells by suppressing TLR4

Osteoarthritis (OA) is a progressive degeneration of articular cartilage with involvement of synovial membrane, and subchondral bone. Recently, cell-based therapies, including the application of stem cells such as mesenchymal stem cells (MSCs), have been introduced for restoration of the articular cartilage. Toll-like receptors (TLRs) were reported to participate in OA progression and MSC chondrogenesis. Here, the role and molecular mechanism of toll like receptor 4 (TLR4) in chondrogenic differentiation of synovium-derived MSCs (SMSCs) were investigated. Molecular markers (CD44, CD90, CD45 and CD14) on SMSC surfaces were identified by flow cytometry. Multi-potential differentiation capacities of SMSCs for chondrogenesis, adipogenesis and osteogenesis were examined by Alcian blue, oil red O and Alizarin red staining, respectively. TLR4 and miR-145-5p levels in SMSCs were assessed using RT-qPCR. The protein expression of TGFB3, Col II, SOX9 and Aggrecan in SMSCs was tested by western blotting. Cytokine secretions were analyzed with ELISA for IL-1β and IL-6. Intracellular NAD⁺ content and NAD⁺/NADH ratio were assessed. The interaction between miR-145-5p and TLR4 was confirmed by RNA pulldown and luciferase reporter assays. In this study, SMSCs were identified to have immunophenotypic characteristics of MSCs. TLR4 knockdown inhibited chondrogenic and osteogenic differentiation of SMSCs. Mechanistically, TLR4 was targeted by miR-145-5p in SMSCs. Moreover, TLR4 elevation offset the inhibitory impact of miR-145-5p upregulation on chondrogenic differentiation of SMSCs. Overall, miR-145-5p restrains chondrogenesis of SMSCs by suppressing TLR4.

Cementless Ceramic-on-Ceramic Total Hip Replacement in Children and Adolescents

Background: total hip replacement (THR) is a rare surgical option in children and adolescents with disabling hip diseases. The aim of this study is to report results from a retrospective cohort of patients aged 18 years or less who underwent cementless Ceramic-on-Ceramic (CoC) THR at a single institution, investigating clinical and radiographic outcomes, survival rates, and reasons for revision of the implants. Materials and methods: we queried the Registry of Prosthetic Orthopedic Implants (RIPO) to identify all children and adolescents undergoing THR between 2000 and 2019 at a single Institution. Inclusion criteria were patients undergoing cementless CoC THR, aged less than 18 years at surgery, followed for at least 2 years. Sixty-eight patients (74 hips) matched all the inclusion criteria and were enrolled in the study. We assessed the clinical and radiographic outcomes, the rate of complications, the survival rate, and reasons for revision of the implants. Results: The mean follow-up was 6.6 ± 4.4 years (range 2-20). The most frequent reason for THR was post-traumatic or chemotherapy-induced avascular necrosis (38%). The overall survival rate of the cohort was 97.6% (95% CI: 84.9-99.7%) at 5 years of follow-up, 94.4% (95% CI: 79.8-98.6%) at 10 years and 15 years of follow-up. Two THR in two patients (2.7%) required revision. With the numbers available, Cox regression analysis could not detect any significant interaction between preoperative or intraoperative variables and implant survivorship (p-value 0.242 to 0.989)." The average HOOS was 85 ± 14.3 (range 30.6-100). Overall, 23 patients (48%) reported excellent HOOS scores (>90 points), 21 patients (44%) reported acceptable HOOS scores (60-90 points) while 4 patients (8%) reported poor outcomes (<60 points). Twenty-one patients (43%) were regularly involved into moderate- to high-intensity sport activities (UCLA ≥ 6). Conclusions: Cementless CoC THR is a successful procedure in children and teenagers, having demonstrated high implant survivorship and low rates of complications and failure. A meticulous preoperative planning and implant selection is mandatory, to avoid implant malposition, which is the main reason of failure and revision in these cases. Further studies are needed to assess the impact of the THR on the psychosocial wellbeing of teenagers, as well as risks and benefits and cost-effectiveness in comparison to the hip preserving surgical procedures.