Knee joint

Deformities of the knee joint In normal adult the knee are in 5-7 degree valgus ; any deviation from this may regarded as deformity . The three common deformities are : 1- bow leg deformity (genu varum) . 2- knock knee (genu valgum) . 3- hyper extension(genu recurvatum) .

Deformities of knee cont. Bow legs & knock knee in babies are so common that are consider to be normal stage of development (physiological) ; in addition to this , rickets may play a role in developing these deformities physiological or renal rickets . Measurement : Bilateral bow leg : distance between the femoral condyls with the legs held in full extension , and the heel touching ; it should be less than 6 cm . Knock knee : the distance between the medial malliolie when the knee are held touching; it is usually less than 8 cm .

Deformities cont. When the cause of the deformity is physiological , it will be corrected spontaneously . And when caused by rickets it will be corrected by treating the rickets . Surgical correction is indicated after this age by stapling or osteotomy usually after the age of 10 .

BLOUNT’S DISEASE It is progressive bow leg deformity due to abnormal growth of the posteromedial part of the proximal tibial epiphysis , which is some time fragmented ; the metaphysis is some what beak shape . The deformity is usually bilateral and it is progressive . The treatment is by corrective osteotomy .

PATELLO-FEMORAL PAIN SYNDROME (CHONDROMALACIA OF THE PATELLA pain and tenderness in the anterior part of the knee. This syndrome is common among active adolescents and young adults. It is often (but not invariably) associated with softening and fibrillation of the articular surface of the patella (chondromalacia patellae) . Treatment : conservative : by physiotherapy . operative .

Loose bodies The knee joint is a common site for loose bodies ; these may be produced by : 1- injuries (chip of bone or cartilage) 2- osteochondritis dissicans . 3- osteoarthritis(piece of bone or cartilage osteophyte) . 4- charcot’s disease . 5- synovial chondromatosis

Clinically It can be symptom less . The usual complaint is attack of sudden locking without injury , the joint get stuck in a position which varies from one attack to another . Some time the locking is momentary and usually the patient can wriggle the knee until it suddenly unlocked . Some time we can feel the L.B. and it usually tend to slip away during palpation so called joint mouse .

X-RAY : Most of the loose bodies are radio opaque so they can be seen by the ordinary x- ray. TREATMENT : Loose bodies should be removed unless the joint is severely affected by osteoarthritis

Acute knee swelling Causes : 1 – haemoarthrosis . 2 – traumatic synovitis . 3 – acute septic arthritis . 4 – aseptic non traumatic synovitis .

haemoarthrosis Swelling immediately after the injury mean blood inside the joint . The knee is very painful and it feel warm, tense and tender …. Later there may be doughy feel . X-ray : important to detect any fracture . Treatment: aspiration under aseptic condition , crepe bandage and back slab , quadriceps ex. Start from the beginning .

Traumatic synovitis Injury stimulate reactive synovitis , typically the swelling appear only after some hours and subside spontaneously over a period of days . The knee may need to be splinted for several days , quadriceps ex. Some time if fluid amount is large , it need aspiration .

Aseptic non traumatic synovitis Acute swelling without history of trauma or sign of infection , suggest gout or pseudo gout . Aspiration from the joint show turbid fluid resembling pus but it is sterile Microscopic ex. By polarized microscope show crystals . Treatment : by anti inflammatory drugs

Chronic swelling of knee Causes : 1 – T.B. 2 – rheumatoid arthritis . 3 – osteoarthritis .