Dr David Su, Medical Director at The Orthopaedic Centre, shares the common causes of chronic knee pain and other knee problems like knee osteoarthritis and Anterior cruciate ligament (ACL) tears.
Chronic knee pain for people below 45 is commonly caused by overdoing and overuse from sports. As for those above 45, the common cause is age-related wear and tear leading to degenerative knee conditions. Three common knee pain problems are Patellofemoral Pain Syndrome (runner’s knee), knee osteoarthritis and knee ligament and cartilage injuries.
Runner’s knee happens when the kneecap is misaligned and rubs against the lower end of the femur. This is often caused by repetitive stress on the knees due to an excessive running or cycling routine. Dr David Su recommended that runners incorporate cross-training in their fitness routine to get a good mix of load on joints and muscles. Some supplements can help to stimulate the formation and repair of the cartilage or keep it from deteriorating.
Knee osteoarthritis, which is the wearing away of the knee cartilage, is the most common form of knee arthritis. There is no cure for this degenerative disease but there are ways to decelerate the cartilage erosion. Shedding 5kg of weight, especially for those who are overweight, can reduce knee pain by 50%. Knee joint injections like hyaluronic acid and platelet rich plasma (PRP) therapy are common temporary measures as well.
ACL tear is the most common ligament injury, especially for soccer players. Physical therapy is often used to restore the knee. However, orthopaedic specialists may advise for ACL reconstruction in the case of complete ACL tears.
Anterior knee pain amongst runners and athletes is very common. It is sometimes referred to as “runner’s knee”. It is a symptom that should not be taken lightly or neglected. Being a “weekend warrior”, it is even more important to pay attention to this symptom as your muscles, tendons and ligaments may not be as well conditioned as that of an active professional athlete.
There are several structures in the front of the knee, the most prominent of which is the patellar bone. This is also sometimes referred to as the kneecap. A tendon called the quadriceps tendon attaches above the patella & a tendon called the patellar tendon attaches below the patella. The patella glides in the front of the knee over the knee bone called the femur, making up the patella-femoral joint.
As we run the muscles contract and move the kneecap in the front of the femur. If our thigh muscles are weak, the pull on this quadriceps tendon is not strong and the kneecap is not able to glide well in the front of the femur. This abnormal gliding can give rise to mechanical knee pain as the patella knocks abnormally on the femur causing pain. Similarly the tendons above and below the knee cap could be inflamed from overuse causing pain. This is known as a tendinosis.
The structures within the knee like the menisci or the cruciate ligaments could also be injured to give the sharp pain. The most common structure to be injured within the knee is the meniscus. The meniscus is a type of cushion that protects the cartilage within the knee during impact. When we accidently twist the knee or land awkwardly while running, its possible for the meniscus to be injured. Sometimes the cartilage on the patella gets injured and the cartilage injury can cause severe pain, especially if there has been repetitive injury to the kneecap. The cartilage over the patella-femoral joint becomes thinned out and that condition is known as chondromalacia. However a cartilage injury of the patellar is uncommon.
It is best to seek an expert medical opinion with an orthopedic surgeon if the knee pain persists. Once a ligament or meniscal knee injury has been ruled out, physiotherapy can be started to strengthen the muscles. A structured physiotherapy program is useful to return a person to sports. Some patients do very well with knee taping and by changing their running pattern. Occasionally if there is structural damage to the knee and when physiotherapy has failed, surgery may be necessary. Knee surgery is usually done via arthroscopic (keyhole) surgery and there is minimal downtime following surgery.
Visual adapted from: https://www.123rf.com/stock-photo/14310222 , last assessed 20th Mar 2018
Seek Early Treatment for Your Knee
Knee pain is the most common problem in patients that Dr Tan sees. He recalls seeing a 69-year-old patient who was asking if there were any other alternatives to total knee replacement surgery for his condition. However, his knee arthritis was already too severe for other treatments to work.
The alternatives to total knee replacement surgery this patient had asked about can be broadly termed as knee preservation surgery. Knee preservation surgery primarily uses minimally invasive keyhole techniques to preserve vital knee components.
The vital components that determine the knee’s functionality include the menisci, cartilage and ligament:
Seeking early treatment is key to the viability of knee preservation surgery. No alternatives to total knee replacement would be available if the knee arthritis or other conditions gets too severe.
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
1. Osteoarthritis Action Alliance. Osteoarthritis Is Widespread and Costly – Both to Individuals and to the Nation. Available at: https://oaaction.unc.edu/policy/cost-of-osteoarthritis. Accessed on 7 May 2019. 2. Chen D, et al. Osteoarthritis: Toward a comprehensive understanding of pathological mechanism. Bone Res. 2017;5:16044. 3. Heidari B. Knee osteoarthritis prevalence, risk factors, pathogenesis and features: Part I. Caspian J Int Med. 2011;2(2):205–212. 4. Felson DT, et al. Defining radiographic incidence and progression of knee osteoarthritis: Suggested modifications of the Kellgren and Lawrence scale. Ann Rheum Dis. 2011;70(11):1884–1886. 5. Scuderi GR, et al. The new knee society knee scoring system. Clin Orthop Relat Res. 2012;470(1):3–19. 6. Mayo Clinic. Osteoarthritis. Available at: https://www.mayoclinic.org/diseases-conditions/osteoarthritis/diagnosis-treatment/drc-20351930. Accessed on 7 May 2019. 7. AAOS. Treatment of Osteoarthritis of the Knee: Evidence-based Guideline 2nd Edition. 2013. Available at: https://www.aaos.org/research/guidelines/treatmentofosteoarthritisofthekneeguideline.pdf. Accessed on 7 May 2019. 8. Anwer S, et al. Effect of home exercise program in patients with knee osteoarthritis: A systematic review and meta-analysis. J Geriatr Phys Ther. 2016;39(1):38–48. 9. Stitik TP, et al. Synvisc® in knee osteoarthritis. Future Rheumatol. 2008;3(3):215–222. 10. SYNVISC/Synvisc-One European Prescribing Information. Naarden, The Netherlands; Genzyme Europe B.V.; 2013. 11. Balazs EA, et al. Hyaluronic acid in synovial fluid. I. Molecular parameters of hyaluronic acid in normal and arthritic human fluids. Arthritis Rheum. 1967;10(4):357–376. 12. Medical Advisory Secretariat. Total knee replacement: An evidence-based analysis. Ont Health Technol Assess Ser. 2005;5(9):1–51. 13. Kim KT, et al. Causes of failure after total knee arthroplasty in osteoarthritis patients 55 years of age or younger. Knee Surg Relat Res. 2014;26(1):13–19. 14. Favero M, et al. Early knee osteoarthritis. RMD Open. 2015;1(Suppl 1):e000062. doi:10.1136/rmdopen-2015-000062.