Early Diagnosis and Management of Knee OA
Knee osteoarthritis (OA) is the most common type of joint disease and leading cause of disability in elderly more than 70 years. It has a huge financial burden costing US$ 100 billion annually in USA.1 OA is an active disease process involving cartilage destruction, subchondral bone thickening, synovial inflammation and new bone formation. The functional changes occurring in an individual can be mild, moderate and severe.2
The main causes for knee OA are:2
Signs and Symptoms:
There are several signs and symptoms of OA, the most prominent of which are pain, stiffness, swelling and crepitus.3 Knee X-ray is generally used for the diagnosis. Kellgren–Lawrence grading system is a radiological classification of knee OA. It progresses from grade 0 to grade 4 and is based on x-rays.4 Knee Society function score is an objective scoring system to rate the knee and patient’s functional abilities such as walking and stair climbing.5
The process underlying OA cannot be reversed, but symptoms can usually be effectively managed with lifestyle changes, physical and other therapies, medications, and surgery. Lifestyle and home remedies include patient education, heat and cold, weight loss, exercise and physical therapy.6 American Academy of Orthopaedic Surgeons (AAOS) 2013 recommendation for symptomatic knee OA includes oral nonsteroidal anti-inflammatory drugs (NSAIDs), topical NSAIDs and tramadol for pain relief.7
Physiotherapy and self-exercises help in joint stiffness, effusion and synovitis, aid in swelling; whereas, physiotherapy and quadriceps strengthening exercises provide relief in crepitus.8
Other modalities of treatment include viscosupplement intra-articular injection such as Synvisc-One® which is cross-linked, has high molecular weight, and mimics healthy and young synovial fluid. The sites of injection are extension superolateral and flexion inferolateral.9-11
Total knee replacement (TKR) is an effective treatment for end-stage disease of the knee. TKR indications are frequent painkillers, reduced walking distance and night pain. The criteria for TKR include older patients with modest activity, younger patients with disabling systemic arthritis and post-traumatic arthritis.12
The leading cause of failure after TKR was polyethylene wear, followed by infection, arthrofibrosis, malalignment/malposition and component loosening. Although the infection rate was lower and the incidence of component loosening was higher in the younger patients when compared to patients >55 years of age, the differences did not demonstrate statistical significance.13
Early diagnosis is important to support and empower the patient to attend to lifestyle factors that influence the disease. In the early stages of the knee OA, X-rays are frequently normal. As the disease progresses, loss of joint space, subchondral sclerosis and osteophyte formation are seen. Regular follow-up helps to maintain management and adherence.14
Early multimodal approach in the treatment of KOA
Knee osteoarthritis (KOA) is a heterogeneous group of conditions that lead to joint symptoms and signs, which are associated with defective integrity of cartilage, in addition to related changes in the underlying bone, synovial tissue, capsule and muscles.1,2 It is an imbalance between cartilage regeneration and damage.2 Hyaline cartilages have an extremely poor regenerative capacity.3
The lifetime risk of KOA is 44.7% with peak prevalence at the age of 65.1,4 Women are affected much more than men.1 It is 4th most common disability worldwide.5 Knee is the largest weight-bearing joint, which bears the brunt of the disease.6
The commonest presentation is pain on activity with morning stiffness and swelling.7 Advanced presentation includes deformities, contractures, stiffness and muscle wastings.7,8 Clinical signs include coronal deformities, capsular contractures, swellings due to free fluids and bony outgrowths.7,8 Diagnosis is performed by clinical examination and radiological imaging.8 There may be a great disparity between clinical presentation and radiological changes.7–9
Despite great advances made in understanding the pathophysiology of KOA, no treatment is currently available that can halt the biochemical and cellular cascade in osteoarthritis (OA).10 Current treatment still focuses on pain relief, maintaining function and halting the progress of early and moderate KOA.11 Surgical treatment is reserved for advanced KOA, unicompartmental diseases, isolated cartilage lesions, mechanical symptoms and severe deformities and stiffness.11,12
Treatment of early and moderate KOA is individualised and multimodal in nature with patient education, lifestyle modification, weight loss, physical therapy, analgesics and injections. Either hyaluronic acid (HA) or steroid injections are used for flare-ups.13–23 Considering a multimodal approach earlier in treatment targets early-stage OA and offers the potential to limit the symptom progression and structural deterioration.16,24
The optimal management of KOA requires a combination of non-pharmacological and pharmacological treatment modalities13–23
HA is a naturally occurring joint product that serves to lubricate joints.25 It also acts as a shock absorber and promotes cartilage regeneration and synthesis of ground substance.25,26 Externally administered HA also provides anti-inflammatory and analgesic properties and enhances endogenous HA production.25,26 HAs and hylan products have been shown to have an excellent safety and tolerability profile with a few serious side effects.26 In addition, combining HAs with other pharmacotherapies can also be considered, as this approach has been shown to be effective.26 American College of Rheumatology (ACR) and Osteoarthritis Research Society International (OARSI) position HA as a second-line treatment following non-pharmacologic therapies for persons who are unresponsive to acetaminophen or nonsteroidal anti-inflammatory drugs or cannot take these medications.26
Hylan G-F 20, a highly cross-linked HA provides far superior clinical properties compared to low-molecular noncross-linked HA products. With a molecular weight of 6 million daltons, it mimics endogenous HA.27 A single GF-20 injection can provide 6 months of symptomatic relief.27 Studies have shown that the combination of hylan G-F 20 with a corticosteroid improved pain scores for the first week compared to those injected with hylan G-F 20 alone. Patients diagnosed with OA within a year were more likely to benefit from hylan G-F 20 than those patients who had been diagnosed longer than a year.26
In conclusion, multimodal approach combining non-pharmacological and pharmacological treatments is still the best option for the management of OA, as recommended in the guidelines of ACR and OARSI.
PRP helps in knee OA: Myths and facts
What is platelet-rich plasma (PRP)?
Osteoarthritis (OA) is a degenerative disease involving joint damage; an inadequate healing response and progressive deterioration of the joint architecture that commonly affects the knee and/or hip joints. 1 Autologous blood-derived products possess much promise in the repair and regeneration of tissue and have important roles in inflammation, angiogenesis, cell migration and metabolism in pathological conditions, including OA.1
Even though blood is mainly a liquid (called plasma), it also contains small solid components (red cells, white cells and platelets). Platelets are best known for their importance in clotting blood. However, platelets also contain hundreds of proteins known as growth factors that are significant in the healing of injuries.2
PRP is plasma with many more platelets than in blood. The concentration of platelets and, thereby, the concentration of growth factors can be 5–10 times greater (or richer) than usual.2
Which are the conditions where PRP can be used for treatment?2
How is PRP prepared?
30–60 mL of blood is drawn from the patient’s arm.
Separate the platelets:3
Extract platelet-rich plasma:1,3
Extract 2–6 mL of platelet-rich plasma.
How does PRP work?
Although it is not exactly clear how PRP works, laboratory studies have shown that the increased concentration of growth factors in PRP can potentially speed up the healing process.2
This can be done in either of the two ways:2
Role of PRP in knee OA1
When can PRP be used in OA?
Is PRP effective in advanced stages of OA?
What is the difference between viscosupplementation and PRP?
Myths and facts6,7
If you are considering PRP or thinking it would work for you, make sure you separate the fact from myths before you move forward with the treatment.
PRP could be effective only in the early stages and when there is injury and some cartilage left for healing, and not in the advanced stages. Initial studies on the use of PRP in OA are positive, but further studies should be conducted prior to its recommended use.