Future trends for unicompartmental arthritis of the knee: injectables & stem cells

Revisiting the role of hyperbaric oxygen therapy in knee injuries: Potential benefits and mechanisms

Knee injury negatively impacts routine activities and quality of life of millions of people every year. Disruption of tendons, ligaments, and articular cartilage are major causes of knee lesions, leading to social and economic losses. Besides the attempts for an optimal recovery of knee function after surgery, the joint healing process is not always adequate given the nature of intra-articular environment. Based on that, different therapeutic methods attempt to improve healing capacity. Hyperbaric oxygen therapy (HBOT) is an innovative biophysical approach that can be used as an adjuvant treatment post-knee surgery, to potentially prevent chronic disorders that commonly follows knee injuries. Given the well-recognized role of HBOT in improving wound healing, further research is necessary to clarify the benefits of HBOT in damaged musculoskeletal tissues, especially knee disorders. Here, we review important mechanisms of action for HBOT-induced healing including the induction of angiogenesis, modulation of inflammation and extracellular matrix components, and activation of parenchyma cells-key events to restore knee function after injury. This review discusses the basic science of the healing process in knee injuries, the role of oxygen during cicatrization, and shed light on the promising actions of HBOT in treating knee disorders, such as tendon, ligament, and cartilage injuries.

Thermosensitive In Situ Gels for Joint Disorders: Pharmaceutical Considerations in Intra-Articular Delivery

The intra-articular administration of conventional drug solutions or dispersions in joint diseases such as osteoarthritis has a relatively short retention time and, therefore, limited therapeutic effect. Thermosensitive polymer solutions that exhibit a sol-gel phase transition near body temperature after injection can prolong drug retention by providing a depot from which the drug release is sustained while relieving inflammation and preventing degradation of the joint complex. Thermosensitive hydrogels have in recent times garnered considerable attention in the intra-articular therapeutics of joint diseases such as osteoarthritis. Among the stimuli-responsive gelling systems, most research has focused on thermosensitive hydrogels. These gels are preferred over other stimuli-sensitive hydrogels since they have well-controlled in situ gelling properties and are also easier to load with drugs. Temperature-sensitive polymers, such as block copolymers or poloxamers, are frequently used to modify their gelation properties, usually in combination with other polymers. They are compatible with most drugs but may pose formulation challenges in terms of their low-response time, highly fragile nature, and low biocompatibility. The stability and biodegradability of implant hydrogels can control the drug release rate and treatment efficacy. This review stresses the application of thermosensitive gels in joint disorders and summarizes recent developments for intra-articular application, including the incorporation of nanoparticles. The hydrogel composition, drug release mechanisms, and the challenges involved in their formulation and storage are also discussed.

Intra-Articular Platelet-Rich Plasma Injections in Knee Osteoarthritis: A Review of Their Current Molecular Mechanisms of Action and Their Degree of Efficacy

Knee osteoarthritis (OA) is estimated to affect more than 10% of the population, with a lifetime risk of 45%. Contemporary guidelines advise control of body weight, therapeutic physical exercise, drug treatment (oral non-steroidal anti-inflammatory drugs, paracetamol, opioids), and mechanical aids (walking aids, braces, orthoses). Nevertheless, these treatments typically have only short-term benefits. Intra-articular corticosteroids are typically advised, but only for short-term pain alleviation, given that their benefits last only a few weeks. The efficacy of hyaluronic acid is controversial. When the aforesaid options fail, total knee arthroplasty is generally recommended as an efficacious treatment. However, it is costly and can involve medical and postoperative complications. Therefore, determining alternate safe and effective treatments for knee OA is paramount. Platelet-rich plasma (PRP) has lately been investigated for the treatment of knee OA. This article reviews recent knowledge concerning PRP’s molecular mechanisms of action. The effectiveness of intra-articular PRP injections in the knee joint remains controversial, although most recent publications show pain alleviation in the short term. Orthopedic surgeons treating people with knee OA are becoming increasingly interested in PRP, despite indecisive clinical data and basic science information. Further studies comparing PRP with placebo are required.

Efficacy of platelet-rich plasma and plasma for symptomatic treatment of knee osteoarthritis: a double-blinded placebo-controlled randomized clinical trial

Background

Platelet-rich plasma (PRP) has a still conflicting efficacy for knee osteoarthritis (KOA) and might be a minimally invasive and safe treatment alternative. The potential benefit of only plasma (non-enriched) has never been investigated. Our aim was to evaluate the efficacy of intra-articular platelet-rich plasma (PRP) and plasma to improve pain and function in participants with KOA over 24 weeks.

Methods

Randomized, double-blind, placebo-controlled trial with 3 groups (n = 62): PRP (n = 20), plasma (n = 21) and saline (n = 21). Two ultrasound-guided knee injections were performed with a 2-week interval. The primary outcome was visual analog scale 0-10 cm (VAS) for overall pain at week 24, with intermediate assessments at weeks 6 and 12. Main secondary outcomes were: KOOS, OMERACT-OARSI criteria and TUGT.

Results

At baseline, 92% of participants were female, with a mean age of 65 years, mean BMI of 28.0 Kg/m²and mean VAS pain of 6.2 cm. Change in pain from baseline at week 24 were -2.9 (SD 2.5), -2.4 (SD 2.5) and -3.5 cm (SD 3.3) for PRP, plasma and saline, respectively (p intergroup = 0.499). There were no differences between the three groups at weeks 6 and 12. Similarly, there were no differences between groups regarding secondary outcomes. The PRP group showed higher frequency of adverse events (65% versus 24% and 33% for plasma and saline, respectively, p = 0.02), mostly mild transitory increase in pain.

Conclusions

PRP and plasma were not superior to placebo for pain and function improvement in KOA over 24 weeks. The PRP group had a higher frequency of mild transitory increase in pain.

Trial registration

ClinicalTrials.gov, NCT03138317, 03/05/2017.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04706-7.

Assessment of the efficacy of intra-articular platelet rich plasma treatment in an ACLT experimental model by dynamic contrast enhancement MRI of knee subchondral bone marrow and MRI T2∗ measurement of articular cartilage

OBJECTIVE

The vascularization of subchondral bone plays a significant role in the progression of knee osteoarthritis (OA). Treatment with platelet-rich plasma (PRP) has positive effects on cartilage lesions. However, PRP's efficacy for subchondral bone marrow lesions and the relationship of these lesions to cartilage are still undiscovered. Therefore, our aims were first to longitudinally investigate the change in subchondral flow by dynamic contrast enhanced MRI and degeneration of cartilage by MRI T2∗ in an anterior cruciate transection rodent (ACLT) model, and second to examine changes in parameters after intra-articular PRP injection.

DESIGN

A 32-week investigation in 18 rats allocated to sham-control, ACLT with normal saline injection (ACLT + NS), and ACLT with PRP injection groups ended with histological evaluation. Another rat was used as a donor of allogenic PRP.

RESULTS

Compared to the sham-control group, the ACLT + NS group had higher subchondral blood volume A (0.051, 95% confidence interval: 0.009, 0.092) and lower venous washout kel (-0.030: -0.055, -0.005) from week 4; lower permeability kep from week 18 (-0.954: -1.339, -0.569); higher cartilage T2∗ values (1.803: 1.504, 2.102) reflecting collagen loss beginning at week 10. For the PRP treatment group, subchondral bone marrow A and cartilage T2∗ decreased from week 10. Histological results confirmed and were correlated with the MRI findings.

CONCLUSION

Subchondral hyper-perfusion plays a vital role in the pathogenesis of OA and was associated with cartilage degeneration. The efficacy of PRP can be observed from reduced perfusion and MRI T2∗ values.

BIOLOGICAL ENHANCEMENTS FOR ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION

The anterior cruciate ligament (ACL) is mostly responsible for providing knee stability. ACL injury has a marked effect on daily activities, causing pain, dysfunction, and elevated healthcare costs. ACL reconstruction (ACLR) is the standard treatment for this injury. However, despite good results, ACLR is associated with a significant rate of failure. In this context, the mechanical and biological causes must be considered. From a biological perspective, the ACLR depends on the osseointegration of the graft in the adjacent bone and the process of intra-articular ligamentization for good results. Here, we discuss the mechanisms underlying the normal graft healing process after ACLR and its biological modulation, thus, presenting novel strategies for biological enhancements of the ACL graft. Level of evidence III, Systematic review of level III studies.

Evidence-based guidelines for intra-articular injection in knee osteoarthritis: Formulating and evaluating research questions

OBJECTIVE

To formulate and evaluate clinical questions about intra-articular injection for knee osteoarthritis in developing clinical practice guidelines and to introduce a new methodology for framing relevant questions.

METHODS

We framed the clinical questions and evaluated the importance of these questions according to the following four steps: (a) first round questionnaire survey intended to get the clinical questions from doctors; (b) evaluating importance of questions via second round questionnaire survey intended to summarize and rank the clinical questions; (c) consensus conference was conducted by clinical and methodological experts; and (d) confirm the important clinical questions according to PICO (Patients, Intervention, Comparison and Outcomes) principles.

RESULTS

After the first round questionnaire survey, the number of clinical questions was 26. Thirteen of these 26 questions were regarded as important questions by the second questionnaire survey. Ultimately, the 13 important clinical questions were determined in a consensus conference. All included questions were deconstructed by clinical experts and methodologists based on the PICO principles.

CONCLUSION

The present study describes an approach about the selection of clinical questions and importance evaluation. Relevant important clinical questions about intra-articular injection for knee osteoarthritis are determined according to the methodology. It could help other guideline developers to utilize this method to frame clinical questions.

A protocol for developing a clinical practice guideline for intra-articular injection for treating knee osteoarthritis

Introduction

Osteoarthritis (OA) is the most prevalent disorder of articulating joints in humans. As one of the steps of advanced pharmacological management, intra-articular treatment is applied in knee OA. However, there is no clinical practice guideline (CPG) involving intra-articular injection for knee OA. Here, we will develop a CPG according to a recognized methodology.

Methods and analysis

We will develop the new CPG according to the Institute of Medicine, the Appraisal of Guidelines for Research & Evaluation Ⅱ (AGREE Ⅱ), and WHO guideline handbook and make recommendations based on systematic reviews. We will establish a Guideline Working Group (including a Guideline Steering Subgroup, a Guideline Development Subgroup, and a Guideline Secretary Subgroup); formulate clinical questions in the form of Population, Intervention, Comparison, Outcomes (PICO); and complete a literature search. The consensus will be developed through evidence syntheses and the Delphi method. We will also consider patients' values or preferences, peer review results, and declaration of interests in developing CPG. The present CPG was registered on the International Practice Guidelines Registry Platform (http://www.guidelines-registry.org/), and the registration number is IPGRP-2016CN004.

Ethics and dissemination

The protocol will provide us a roadmap to systematically develop evidence-based CPG for intra-articular injection for knee OA. The work will be disseminated electronically and in print. The guideline would be the first CPG that is developed primarily by orthopedic specialists in China and strictly based on systematic methodology.

Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

Intra-articular treatment of knee osteoarthritis: from anti-inflammatories to products of regenerative medicine

OBJECTIVES

Knee osteoarthritis (OA) is a debilitating condition that may ultimately require total knee arthroplasty (TKA). Non-operative treatments are bracing, oral analgesics, physical therapy, and intra-articular knee injection (IAKI). The objective of this paper is to provide a systematic literature review regarding intra-articular treatment of knee OA and insight into promising new products of regenerative medicine that may eventually have a substantial effect on treatment.

METHODS

A literature search was executed using Medline, Cochrane, and Embase with keywords "knee osteoarthritis" and "injection." Specifically, 45 articles that discussed intra-articular knee injection using corticosteroids, hyaluronic acid, analgesics, local anesthetics, and newer products of regenerative medicine, such as platelet-rich plasma (PRP) and mesenchymal stem cells (MSC), were analyzed. Of these, eleven were level 1, three were level 2, twelve were level 3, two were level 4, and seventeen were level 5 evidence. Papers included animal models.

RESULTS

Local anesthetics have potential side effects and may only be effective for a few hours. Morphine and ketorolac may provide significant pain relief for 24 hours. Corticosteroids may give patients weeks to months of effective analgesia, but complications may occur, such as systemic hyperglycemia, septic arthritis, and joint degradation . Hyaluronic acid is a natural component of synovial fluid, but efficacy with respect to analgesia is controversial. Platelet-rich plasma formulations, autologous conditioned serum, autologous protein solution, and mesenchymal stem cell injections contain anti-inflammatory molecules and have been proposed to attenuate joint destruction or potentially remodel the joint.

CONCLUSIONS

Currently, knee OA treatment does not address the progressively inflammatory environment of the joint. More investigation is needed regarding products of regenerative medicine, but they may ultimately have profound implications in the way knee OA is managed.