Keywords
arthroscopy - articular cartilage - biomarkers - physical exercise - intra-articular
infiltrations - knee - osteoarthritis - physical exercise
Introduction
Osteoarthritis (OA) causes cartilage degradation, bone remodeling, osteophyte formation,
and synovial inflammation, resulting in pain, stiffness, edema, and loss of joint
function. It is a significant cause of disability among adults and older subjects.[1]
[2] Populational aging and the progressively higher prevalence of obesity are increasing
the incidence of this disease.[2]
The most common knee disease, OA may result in repeated joint effusion and functional
limitation.[3] A slow and steady understanding of the pathophysiology of knee OA has been witnessed
in recent decades. However, gaps regarding its pathogenesis remain, negatively impacting
drug development and innovation. The lack of new medications and modifying drugs for
knee OA treatment highlights the need for lifestyle changes to delay surgical intervention.[4] Furthermore, medical societies recommend low-impact physical activity, and surgical
interventions may have conflicting outcomes.[5]
[6]
[7]
Additionally, the use of biological therapies has been increasing as alternatives
to OA treatment, particularly intra-articular (IA) infiltrations. Hyaluronic acid
(HA) is widely known as a safe conservative treatment for OA in the knee and other
joints.[8] It provides pain relief, stimulates synovial fluid production, and cushions and
lubricates joint surfaces.[9]
A growing body of scientific literature supports the use of IA infiltrations with
HA for knee OA over placebo and other therapies. Acharya et al.[10] analyzed the effectiveness of IA with HA regarding pain, functional capacity, and
quality of life in patients with early primary knee OA. These authors[10] reported short-term beneficial effects (up to one year), observing a decreasing
trend in pain intensity and a progressive improvement in physical functioning and
health-related quality of life after a single intervention.
Knee OA is multifactorial and influenced by several local, systemic, and external
aspects. In addition, its progress and therapeutic responses highly depend on the
characteristics of each subject. To better understand this condition, the present
study aimed to gather information about its pathophysiology, clinical diagnosis, and
updates on its treatment.
Pathophysiology of Knee Osteoarthritis
Pathophysiology of Knee Osteoarthritis
Osteoarthritis results from complex biological processes affecting cartilage, bone,
ligaments, synovium, meniscus, periarticular fat, and muscles. It usually presents
with joint space narrowing (JSN) due to articular cartilage loss, meniscal degeneration,
and bone changes, including subchondral bone sclerosis and osteophytes.[11]
[12]
The biomechanical environment can influence OA development. Varus alignment shifts
the load medially, increasing the risk of knee OA in the medial compartment, while
valgus alignment shifts the load laterally, triggering OA in the lateral compartment.
Additionally, previous knee trauma increases the risk of OA by 3.86 times.[13]
Mechanical overload often accounts for starting the process of cartilage damage, which
later evolves into inflammation, causing joint degradation. The primary precursors
of this inflammation process include interleukin-1 (IL-1) and tumor necrosis factor
(TNF). These molecules maximize the expression of metalloproteinases and nitric oxide,
the main catabolic agents synthesized by chondrocytes in response to injury.[14] Therefore, OA is an inflammatory disease of the entire synovial joint, comprising
the mechanical and structural degeneration of the articular cartilage and triggering
functional changes in the entire joint.[4]
The development of OA is slow, and the pain can be progressive;[12] OA is a major cause of pain and disability, directly affecting quality of life.[2] It may result from several factors, including age, body weight disorders, knee joint
overload, prolonged hyperflexion, and axis deviations.[3]
According to Primorac et al.,[15] the prevalence of knee OA is higher in adults aged ≥ 60 years, representing one
of the most significant causes of disability among elderly subjects. In addition,
the risk is higher in obese people (body mass index [BMI] ≥ 30 kg/m2) than in non-obese people (19.7% versus 10.9% respectively).
Clinical Diagnosis and Classification Systems
Clinical Diagnosis and Classification Systems
The diagnosis is initially clinical, based on symptoms of pain, stiffness, and functional
limitations, as well as a thorough physical examination with crepitus, pain, restricted
mobility, joint sensitivity, and bone enlargement observation.[2] Weight-bearing knee radiographs help confirm the diagnosis and enable the classification
of knee OA and the observation of structural damage. In addition, they improve specificity
when osteophytes or JSN are present.[16]
Magnetic resonance imaging (MRI) reveals the effects of knee OA on the cartilage,
meniscus, synovial membrane, and subchondral bone. Moreover, a tool developed by Cho
et al.[17] uses infrared immunoliposomes against type-II collagen antibodies for early OA diagnosis
and treatment.
Classifications are critical in knee surgery since effective classification systems
can guide prognostic estimates. The recent publication by Pires et al.[18], “Classifications and flowcharts in knee surgery,” is a Brazilian reference study
that combines several classifications, flowcharts, and questionnaires to aid in the
diagnosis and decision-making by specialists.
Following the classifications for degenerative lesions,[18] the most common method for radiographic definition is the Kellgren-Lawrence classification
system. The overall joint score classifies OA as follows: grade 0 represents no pathological
findings; grade 1 indicates potential JSN and edge osteophytes; grade 2 indicates
potential JSN and definitive osteophytes; grade 3 establishes the presence of JSN,
multiple osteophytes, some subchondral sclerosis, and potential bone contour deformity;
and grade 4 denotes notable JSN, severe subchondral sclerosis, definitive bone contour
deformity, and the presence of large osteophytes.[19]
Clinical Examination and Imaging
Clinical Examination and Imaging
About 40% of the population aged over 65 years has symptomatic knee OA. Early detection
and intervention are paramount to reduce morbidity and disability, resulting in better
self-reliance. Radiography is the first investigation of choice for OA patients presenting
with knee pain. Community-based studies[19] have shown that 40% to 80% of subjects with OA and radiographic knee changes are
symptomatic, and that severe radiographic findings are associated with reports of
pain that is more intense. However, there is a high degree of discordance between
clinical and radiographic findings, and radiological OA classification is inaccurate
in the early stages. The multifactorial origin of pain may explain this discrepancy
between pain and radiographic findings.[19]
The discrepancy between the physical and imaging examinations, especially concerning
symptoms, can be explained by the propensity of some OA patients to develop sensitized
central nociceptive circuits that increase pain during various states of aggression
to peripheral tissues.[20]
[21] This abnormality, known as central sensitization, is a maladaptive nociceptive process
involving complex neuroplastic changes amplifying pain at multiple levels of the neuraxis.[20] Since central sensitization correlates with the activation of neural circuits implicated
in the descending facilitation of pain and, as such, is a risk factor for the development
and maintenance of chronic pain, it is essential to identify which patients present
abnormal responses to relevant painful stimuli.
Biomarkers
An accurate and reliable biomarker must present specificity for a given condition
and reflect the actual activity of the disease, monitor the changes achieved with
therapy, and predict the prognosis.[20] Thus, most biochemical markers of OA characterize cartilage renewal. The most commonly
investigated markers include the following: for extracellular matrix (ECM) degradation
– urinary C-telopeptide fragments of type-II collagen (uCTX-II), Coll2–1, C2C, C2M,
Coll2–1NO2, cartilage oligomeric matrix protein (COMP), aggrecan epitopes (ARGS, TEGE,
FFGV), fibulin-3 epitopes (Fib3–1, Fib3–2, Fib3–3) etc.; and, for ECM synthesis, PIIANP,
PIIBNP, CPII, CS846 etc.[21] The uCTX-II) is one of the best-known biochemical markers of OA, achieving a superior
predictive profile compared to others.
According to the literature, several conditions can affect biomarker levels. Some
evidence suggests that physical activity, hormonal levels, medications, and the sex
of the patient may result in biomarker level fluctuations. Tanishi et al.[22] observed that uCTX-II levels differed significantly between men and women and in
premenopausal and post-menopausal women.
Due to its ability to distinguish between healthy subjects and OA patients, another
potential biochemical marker widely reported in the literature is COMP,[23] which also has some potential prognostic capabilities. Although some studies have
reported conflicting results, a meta-analysis[23] showed that these biochemical markers (that is, COMP and CTX-II) may be effective
to diagnose OA, assess prognosis progression, and differentiate between healthy subjects
and those with OA.
The emergence of these biomarkers is relatively recent, and the best strategies for
their application remain under study, in terms of technology and medical research,
with the goal of developing reliable detection methods.
Treatments
The first-line treatment for knee OA does not involve surgical interventions, and
management may be multimodal. However, if these therapies are unsuccessful, one must
consider surgical treatment. Although OA has no cure, several surgical and non-surgical
treatment options are available to help manage pain and maintain the health of the
affected patients.[12]
The following section will discuss the most widespread treatments according to their
current level of recommendation.
Materials and Methods
Search Strategy
A bibliographical survey was performed in PubMed, MEDLINE, and Embase for studies
published until February 20, 2023. The descriptors included Updates; Knee
Osteoarthrosis, and Treatment, and the filters included Randomized Controlled Trial, Randomized Clinical Trial, Meta-Analysis, Systematic Reviews, and Cohort.
Eligibility and Selection Criteria
The retrieved studies met the following inclusion criteria:
-
Studies related to the proposed topic;
-
Studies with level of evidence of I to III;
-
Articles in English, Spanish, and Portuguese;
-
Research carried out on humans;
-
Articles available in full versions.
The exclusion criterium was the following:
Results
Identification of Studies and Characteristics
Following the search strategy, we found 41 studies with the aforementioned descriptors.
These studies underwent a new assessment regarding their design, relevance, study
type filters, and inclusion criteria. This assessment resulted in eight studies available
in full and included according to category and type of treatment.
Surgical Treatments
Arthroscopy
Arthroscopy removes debris and crystals released in the joint cavity affected by OA,
regularizing the joint surface.[24] A literature survey retrieved 26 systematic reviews and meta-analyses describing
the results of 6,418 patients with a mean age of 47 ± 19 years ([Figs. 1] and [2]).
Fig. 1 Graphical representation of the outcomes of studies assessing arthroscopy for the
treatment of knee degenerative disease.
Fig. 2 Temporal description of the literature included by year of publication.
Arthroscopic surgery for degenerative knee disease has been the focus of several recently
published randomized clinical trials (RCTs), high-quality systematic reviews, and
meta-analyses. Although pioneering studies have demonstrated that minimally-invasive
arthroscopy had promising results, their strength was insufficient for a recommendation.
Current clinical studies comparing arthroscopic joint debridement with placebo surgery
or conservative treatment have demonstrated that arthroscopy is no longer effective
and has no recommendation.[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[25]
A recent systematic review[11] published in the British Medical Journal strongly recommended against arthroscopy in patients with degenerative knee disease,
emphasizing the importance of fully utilizing appropriate conservative treatment options.
In particular, the recommendations directed clinicians to maximize exercise therapy,
as the results presented in RCTs demonstrate that arthroscopic surgeries are not superior
to complete physiotherapy protocols.[11] Another systematic review of eight RCTs evaluating arthroscopic surgery in degenerative
meniscal injuries found moderate evidence suggesting no clinical benefit of arthroscopic
meniscal debridement for degenerative meniscal tears compared to non-surgical or sham
treatments in middle-aged OA patients.[10]
[26]
[27]
[28]
In a prospective cohort, Navarro et al.[29] aimed to ascertain whether knee arthroscopy to treat meniscal damage by OA delayed
knee replacement compared with physiotherapy alone. The main findings were that the
cumulative incidence of knee replacement was modest but significantly higher for subjects
undergoing arthroscopy than physical therapy alone (risk ratio: 1.30; 95% confidence
interval: 1. 17–1.44; p < 0.001). The authors[29] concluded that, for patients with meniscal damage complicated by OA, those who underwent
arthroscopy were 30% more likely to have partial or total knee replacement surgery
at any point during follow-up compared with those undergoing physical therapy alone.
Indications
For all these reasons, many researchers limit the indications for arthroscopy. The
technique still presents advantages in the early stages of OA, in which movement limitation
is mechanical, and there are free articular bodies. However, physical therapy must
accompany arthroscopy.[26]
For Zhao et al.,[27] arthroscopy presents no advantages over the several surgical options due to the
weak and scarce evidence supporting its application. Likewise, recent studies suggest
that arthroscopy may not be beneficial for patients with chronic degenerative meniscal
tears, emphasizing the importance of conservative follow-up for the management of
knee OA.[28]
The small and inconsequential benefit observed in interventions including arthroscopy
for the degenerated knee is time-limited and absent within one to two years after
surgery. Knee arthroscopy is associated with harm. Together, these findings do not
support arthroscopic surgery for middle-aged or elderly patients with knee pain with
or without signs of OA.
Arthroplasty
Arthroplasty is a surgical option to treat patients with extreme cases of knee joint
degeneration; it can be total (total knee replacement, TKR) or unicompartmental (partial
knee replacement, PKR), depending on the degree of OA.[30]
In the literature survey, we found 22 systematic reviews and meta-analyses describing
the outcomes of 14,095 patients with a mean age of 58 ± 21 years ([Figs. 3] and [4]).
Fig. 3 Graphical representation of the outcomes of studies assessing (total or partial)
arthroplasty for the treatment of knee degenerative disease.
Fig. 4 Temporal description of the literature included by year of publication.
For OA limited to a single compartment, PKR or unloading osteotomy may be an option.
Their recommendation includes young, active patients because of the risks and limited
durability of TKR. In contrast, TKR is a common, safe method in elderly patients with
advanced knee OA and the gold-standard surgical treatment for advanced cases.[30]
An RCT[31] demonstrated that TKR is superior to non-surgical treatment alone in relieving pain
in patients with moderate to severe knee OA and in improving function and quality
of life after one year. However, both groups presented clinically relevant improvements,
and patients undergoing TKR had more severe side effects. Furthermore, resection of
the interpatellar fat pad during TKR is the subject of ongoing debate, with no clear
consensus.[31]
Indications
The indication for TKR includes patients with advanced joint degeneration process
and subjects older than 60 years. It is also the gold-standard treatment in this last
group of patients. The indication for PKR includes young, active patients due to the
risks and limited durability of TKR.
Osteotomy
High tibial osteotomy (HTO) has been used for over sixty years as a clinical exercise.
This technique, performed around the knee, aims to maintain a regular anatomical structure,
achieve better functional recovery of the knee joint, attenuate joint softness, reduce
the cartilage degeneration rate, and prevent or postpone joint replacement.[32] This technique relies on a controlled osteotomy, transferring the weight-bearing
axis from the degenerate compartment to the healthy compartment to realign the lower
limb.[33] As a result, this procedure interferes little with soft tissues and often has no
harmful effects on the stability and mobility of the knee joint.[34]
In the literature survey, we found 19 systematic reviews and meta-analyses describing
the outcomes of 8,412 patients with a mean age of 51 ± 7 years ([Figs. 5] and [6]).
Fig. 5 Graphical representation of the outcomes of studies assessing osteotomy for the treatment
of knee degenerative disease.
Fig. 6 Temporal description of the literature included by year of publication.
High tibial osteotomy comprises two main techniques: closing-wedge HTO (CWHTO) and
opening-wedge OTA (OWHTO).[34] These procedures may occur proximal or distal to the knee joint. In general, if
knee OA is in the medial compartment, HTO is most commonly performed by operating
on the upper tibia. In OA affecting the lateral compartment, HTO is usually performed
on the lower femur. However, one must always measure the distal lateral femoral angles
and the medial proximal tibial angle to optimize the correct osteotomy location and
whether it will be an addition or subtraction following the principles described by
Paley and Tetsworth.[35]
The indication for HTO includes young, active subjects, often under the age 50. Several
factors may influence HTO outcomes.[36] Valeiy Evgenievich et al.[37] demonstrated a greater efficiency of HTO in the second stage of knee OA than in
the third stage. These authors also noted that age and correction angle do not affect
the outcome, but high BMI is associated with worse results and complications. The
literature heterogeneously reports its imprecision, including lower functional outcomes,
OA progression, and conversion to arthroplasty.
Lastly, HTO is an autonomous treatment, but the process of limb alignment intrinsically
relates to the joint and stabilizing knee structures. Therefore, one must consider
combining HTO with other osteotomies and arthroplasties. In addition, it may be a
treatment strategy in procedures aiming to stabilize the knee and restore the cartilage.
Indications
High tibial osteotomy is suitable for young patients, especially those with OA and
partially preserved cartilage. For knee biomechanics correction, the highest efficacy
of HTO occurs in patients with second-stage knee OA compared to the third stage.
Proximal fibular osteotomy (PFO) is more suitable for patients with many complications
and low surgical tolerance, as it can reduce operative time, intraoperative bleeding,
hospitalization time, and postoperative complications, with some advantages.
Non-surgical Treatments
Pharmacological Therapies
Pharmacological therapy for OA is purely symptomatic and, in most cases, successfully
assures the maintenance of the patient's mobility. It may include paracetamol, topical
or oral non-steroidal anti-inflammatory drugs (NSAIDs), or intra-articular corticosteroids.
Although paracetamol is a drug of considerable efficacy, safety, and low cost, the
Osteoarthritis Research Society International (OARSI) guidelines recommend its administration
in conservative doses and periods because of the increased risk of gastrointestinal
and liver disorders.[38]
In parallel, NSAIDs are the first-line pharmacological treatment for OA, with evidence
proven by placebo-controlled trials. Topical NSAIDs often result in less gastrointestinal
toxicity than oral NSAIDs. However, one must discuss alternatives to NSAIDs for patients
who are susceptible or present risk factors for the adverse effects of the medication.
It is worth highlighting that drugs should complement, not replace, the non-pharmacological
treatment.
Indications
Patients with symptomatic OA.
Intra-articular Infiltrations
Biological therapies have been increasingly sought after as alternatives for OA treatment.
Intra-articular infiltrations stand out as treatments approved by the Food and Drug
Administration (FDA) and the European Medicines Agency (EMA).[39] These infiltrations enable the administration of a concentrated drug dosage and
its distribution locally and throughout the joint. Thus, these drugs can access places
that it would not with oral intake. Furthermore, IA infiltrations offer much better
bioavailability and limit the systemic drug passage, reducing the risk of side effects.[39]
[40]
Indications
Intra-articular infiltrations are an adjuvant therapy for OA treatment, especially
in patients already under chronic systemic treatment, such as elderly subjects.
Hyaluronic Acid (HA)
A natural substance found in the synovial fluid surrounding joints, HA is a polysaccharide
from the glycosaminoglycan family that smoothly reduces attrition during movement,
cushioning the shock between loads. Subjects with OA present lower HA levels. Therefore,
exogenous HA infiltrations can help restore the elastic and viscous properties of
the synovial fluid, minimizing pain and improving function.[12] Hyaluronic acid also increases shock absorption, provides synovial fluid lubrication,
and acts on joint nociceptive response with reflex quadriceps muscle inhibition. The
anti-inflammatory, analgesic, and chondroprotective action of HA results from the
modulation of intra- and extracellular inflammation cascades. In addition to being
safe and effective in treating pain due to patellar chondropathy, it improves mobility
and slows down the degenerative process.[8]
Russu et al.[41] investigated the treatment of knee OA with HA derivative infiltrations and observed
satisfactory outcomes six months after the procedure, showing therapeutic efficiency
in treating moderate to severe knee OA. In contrast, HA application alone yielded
less significant outcomes concerning pain in patients under treatment when compared
to HA combined with platelet-rich plasma (PRP).[42]
However, some authors mention the occurrence of allergic side effects related to the
product's origin. Pain and swelling after injection may result from the high molecular
weight and different pharmaceutical formulations of HA. The other major challenge
of HA treatment is the need for multiple injections to obtain the desired efficacy.
As such, multiple injections could result in more cost, pain, and potential infection.
Therefore, updates and innovations in single-dose high molecular weight medications
have gained prominence in the therapeutic arsenal, with good outcomes in the joint
functional status.
Indications
Infiltration of HA is an adjuvant therapy for OA treatment, mainly regarding symptoms
and function, but its evidence still lacks scientific strength.
Platelet-Rich Plasma (PRP)
A blood-derived product with a high platelet concentration in a small plasma volume,
PRP plays a role in the release of several growth factors (insulin-like growth factor
1 [IGF-1], platelet-derived growth factor [PDGF], epidermal growth factor [EGF], vascular
epidermal growth factor [VEGF], and transforming growth factor-β [TGF-β]). All of
these molecules act in the initial phase of healing and tissue regeneration. The type
of growth factors in PRP and their levels vary in each subject. Moreover, its mechanism
is not fully understood, and it is difficult to determine the effects of each type
of factor.[43] The use of PRP in studies has already demonstrated considerable and complex biological
activities, such as cell proliferation, anti-apoptotic activity, cartilage regeneration,
collagen synthesis, and angiogenesis maximization.[43]
Saita et al.[44] studied 517 patients receiving 3 PRP injections and analyzed the outcomes per the
severity of knee OA. The authors state that the therapy is approximately 60% effective
depending on the severity of the disease. Furthermore, this efficacy is independent
of age, gender, body weight, or platelet count.[44]
[45] Knop et al.,[46] based on RCTs, reported that PRP significantly improves joint pain and function
when compared with HA, including sustained response for up to two years in milder
knee OA cases.
Furthermore, it is worth highlighting that the Brazilian Federal Council of Medicine
(Conselho Federal de Medicinas, CFM, in Portuguese), in its Resolution no. 2,128/2015,
considers PRP an experimental procedure and only allows its use in clinical trials
within the protocols of the Brazilian Research Ethics Committee/Research Ethics National
Committee (Comitês de Ética em Pesquisa/Comissão Nacional de Ética em Pesquisa CEP/CONEP,
in Portuguese) system. Likewise, the Brazilian National Health Regulatory Agency (Agência
Nacional de Vigilância Sanitária, ANVISA, in Portuguese), in Technical Note no. 12/2015,
ratified the experimental use of PRP as a product with no proven therapeutic utility,
requiring more scientific evidence for clinical use.
Indications
Platelet-rich plasma is an adjuvant therapy for OA treatment, mainly concerning pain;
it significantly improves pain and joint function compared to HA, including sustained
response for up to two years in milder cases of knee OA.
Stem Cells
Stem-cell therapy emerges as a milestone in regenerative medicine for knee OA treatment,
and its potential is deemed high.[47] Mesenchymal stromal/stem cells (MSCs), such as bone marrow, adipose tissue, and
synovium stem cells, aid in damaged cartilage regeneration and are reportedly safe.[48]
In a trial,[49] nine patients diagnosed with knee OA received a single injection of adipose-derived
mesenchymal stem cells (AD-MSCs) at a concentration of 0.5–1.0 × 107 cells. The follow-up period was of 18 months. The results showed significant improvement
in all aspects evaluated in the initial six months, being sustained up to the end
of the treatment.[49] An RCT by Chen et al.[50] assessed the safety and efficacy of allogeneic adipose-derived stem cells (ADSCs;
ELIXCYTE, UnicoCell Biomed Co., Ltd., Taipei, Taiwan) infiltration for knee OA treatment.
Patients either received one dose of HA or three doses of ELIXCYTE. ELIXCYTE was more
effective than HA, providing an early pain reduction and functional improvements.[50]
Although studies have shown that MSCs yield promising results in improving patients'
clinical and structural conditions, there is still limited evidence, a lack of procedural
standardization, and no long-term advantages.
Indications
Mesenchymal stem cells are adjuvant therapy for OA treatment, mainly for pain.
Prolotherapy with dextrose
The fundamental principle of dextrose prolotherapy is the injection of small volumes
of an irritating solution into areas of painful attachments (ligaments, tendons, and
adjacent joint spaces) at several treatment sessions. The mechanism of action remains
unclear. However, hypotheses suggest that prolotherapy stimulates local healing of
chronically-damaged extra- and intra-articular tissue, but with no definitive evidence.
The literature[51] reports that prolotherapy injections may be appropriate to treat the multifactorial
cause of OA-related knee pain.
Indications
Dextrose prolotherapy is an adjuvant method for OA treatment, mainly concerning pain,
but there is no current evidence about it.
Genicular Nerve Block
In the literature survey, we retrieved seven randomized studies and one systematic
review.
Genicular nerve block (GNB) is a therapeutic alternative aimed at blocking the three
sensory nerves of the knee: the lateral and medial superior genicular nerve and the
medial inferior genicular nerve. The block hinders the transmission of pain to the
central nervous system and results in functional improvement.[52] Ultrasound can guide GNB, enabling direct visualization of the structures and real-time
control of the anesthetic application.[53] Thus, the block is performed more efficiently, generating lower latency, dependence
on anatomical information, and lower use of the anesthetic solution, in addition to
providing greater safety.[54]
A study[54] analyzed four elderly patients with advanced knee OA, presenting limited movement
and chronic pain, who underwent ultrasound-guided GNB. The outcomes were satisfactory,
with a significant improvement in pain and functional capacity and no complications.[54] A twelve-week analysis[55] compared the efficiency of IA block therapy and GNB. Both techniques resulted in
satisfactory outcomes, minimizing pain, improving nighttime sleep quality, and facilitating
the performance of daily activities. However, the study reports that GNB represents
a safer, minimally-invasive, and highly-efficient alternative.[55]
Indications
There is reasonable evidence to at least target the superior medial genicular nerve,
the inferior medial genicular nerve, and the inferior medial genicular nerve using
local anesthetics, corticosteroids, or alcohol to reduce pain and improve knee function
in patients with chronic knee OA under ultrasound guidance. The procedure is safe,
but more research is needed to determine the ideal interventional approach.
Acupuncture
Acupuncture is a well-known technique to treat several conditions by inserting fine
needles in specific anatomical points.[56] Studies on acupuncture to minimize knee OA pain and provide functional rehabilitation
have been increasing, demonstrating that this therapy acts to mitigate symptoms due
to the activation of various chemical elements that present bioactivity through peripheral,
spinal, and supraspinal mechanisms.[57]
Teixeira et al.[6] evaluated the treatment of two patients with knee OA through one weekly, thirty-minute
acupuncture session (for six weeks) at four local points. The researchers[6] reported pain minimization and increased range and mobility of the knee joint flexion,
demonstrating that the technique is efficient as an alternative or complementary treatment
for OA, even in a short period. In general, acupuncture can improve the subjective
perception of the quality of life of patients with OA, enabling a better performance
of daily activities. Nevertheless, one must consider factors such as the number and
duration of acupuncture sessions, the patient's health status, and the time of prevalence
of the disease.
Indications
Acupuncture plays a role in OA treatment, especially concerning pain.
Physical Exercises
Clinical guidelines for knee OA management suggest that patients should receive a
core set of non-pharmacological interventions, including education, weight loss, and
low-impact exercise (strengthening, cardiovascular exercise, and/or mind-body exercises,
such as yoga or tai chi).[58] A recent systematic review[59] evaluated different RCTs on the effectiveness of land-based physical activities
for patients with knee OA. In these studies, patients with this joint condition either
underwent exercises or did not perform exercises or receive any treatment. The authors[59] found that the group performing land-based physical activities consistently presented
reduced pain and improved their physical shape and quality of life.
Indications
Current research[60] indicates that aerobic activity for 150 minutes a week at moderate intensity, moderate/vigorous
physical activity, or muscle strengthening exercises 2 days a week bring many benefits
to subjects with preexisting knee OA.
Miscellaneous Interventions
Another therapeutic resource is the lateral wedge insole. Recent research[61] concluded that a customized external orthosis (fixed below the sole) resulted in
a higher improvement in pain and functional status than a control orthosis. Likewise,
varus or valgus correction orthoses (altering biomechanics) and shifting the load
to the least compromised compartment are alternatives to gain function and improve
pain.
Final Considerations
Knee OA is a highly prevalent and disabling disease. In the past few years, we gained
significant information about the cause and pathogenesis of OA, leading to a new era
in OA therapy. However, management should not be generalized and requires adaptation
according to each subject, enabling the establishment of the ideal intervention for
each case.
Changing lifestyles, practicing physical exercise, and acupuncture, among others,
are minimally-invasive methods for initial treatment, leaving surgical procedures
as alternatives for cases in which these methods do not provide satisfactory responses.
Therefore, the search for disease-modifying drugs for OA treatment has become a priority
in orthopedics. Hyaluronic acid is safe and effective in treating OA-related pain
in the knee and other joints, confirming that it may have some disease-modifying properties.
In conclusion, further studies on this topic are required to achieve better scientific
knowledge and then understand and fill the remaining gaps.
