Knee Pain
The knee is a hinge joint formed between the tibia and femur (tibio-femoral). The patella glides over the front of femoral condyles to form a patellofemoral joint. The stability of the knee depends primarily upon its ligaments.
Causes
- Traumatic injuries to the knee joint
- Injuries to the ligaments of the knee
- Injuries to the menisci of the knee
- Tuberculosis of knee
- Osteoarthritis of knee joint
- Rheumatoid arthritis of knee joint
- Deformities of knee joint- genu valgum, genu varum, genu recurvatum
- Popliteal cyst
Osteoarthritis Knee
Osteoarthritis (OA) is a degenerative joint disease. Aetiology is multifactorial, and still not understood. Commonly it is thought to be wear and tear of joints as one ages. It occurs in elderly people, mostly in the major joints of the lower limb, frequently bilaterally.
Types: Two types of Osteoarthritis are recognized – Primary & Secondary.
- Primary OA: It occurs in old age, mainly in the weight bearing joints (knee and hip). Primary OA is commoner than secondary OA.
- Secondary OA: In this type, there is an underlying primary disease of the joint which leads to degeneration of the joint, often many years later. It may occur at any age after adolescence, and occurs commonly at the hip.
Predisposing Factors are:
- Congenital Maldevelopment of a Joint
- Irregularity of the joint surfaces from previous trauma
- Previous Disease producing a damaged Articular surface
- Internal derangement of the knee, such as a loose body
- mal-alignment (bow legs etc.)
- obesity and excessive weight.
Pathology
Osteoarthritis is a degenerative condition primarily affecting the articular cartilage. The first change observed is an increase in water content and depletion of the proteoglycans from the cartilage matrix. Repeated weight bearing on such a cartilage leads to its fbrillation. The cartilage gets abraded by the grinding mechanism at work at the points of contact between the apposing articular surfaces, until eventually the underlying bone is exposed. With further ‘rubbing’, the subchondral bone becomes hard and glossy. Meanwhile,the bone at the margins of the joint hypertrophies to form a rim of projecting spurs known as osteophytes. The loose flakes of cartilage incite synovial inflammation and thickening of the capsule, leading to deformity and stiffness of the joint.
Clinical Features
- Pain is the earliest symptom. It occurs intermittently in the beginning, but becomes constant over months or years. Initially, it is dull pain and comes on starting an activity after a period of rest, but later it becomes worse cramp-like, and comes after activity.
- Coarse crepitus may be complained by some patients.
- Swelling of the joint is usually a late feature, and is due to the effusion caused by inflammation of the synovial tissues
- Stiffness is initially due to pain and muscle spasm; but later, capsular contracture and incongruity of the joint surface contribute to it.
- Other symptoms are: a feeling of 'instability' of the joint, and 'locking' resulting from loose bodies and frayed menisci
- Terminal limitation of joint movement
Stages of Osteoarthritis
- Garade-0 normal, no pathological features
- Grade -1 narrowing of joint space, possible osteophyte formation.
- Grade-2 definite osteophyte formation and possible narrowing of joint space
- Grade-3 moderate multiple osteophytes, definite narrowing of joint space,sclerosis, possible deformity of bony ends
- Grade -4 large osteophytes, marked narrowing of joint space, sclerosis, definite deformity of bony ends.
