deformities of the knee

1. Deformities of the knee
Knock knee (genu valgum)
Bow legs (genu varum)
Genu recurvatum

2. Genuvalgum
(Gum– kneesin
contact)
 This is a condition where the knees are abnormally
approximated and the ankles abnormally divergent.

3. Causes
 Idiopathic
 Post-traumatic
• Fractures of the lateral femoral or tibial condyles.
• Damage to the lat. Side of the lower femoral or upper
tibial epiphysis or epiphyseal plates.
 Post-inflammatory – damage to the lateral side of the
lower femoral or upper tibial epiphyses or epiphyseal
plates by infection.
 Neoplastic causes – a tumour causing a growth disparity
at the epiphyseal plate e.g. chondroblastoma.
 Bone softening
• Rickets and osteomalacia
• Bone dysplasias
• Rheumatoid arthritis.

4. Causes
 Stretching of joints
• Charcot’s disease
• Paralytic disease
 Cartilage thinning
• OA of the lateral compartment of the knee.

5. Clinicalfeatures
 Physiological genu valgum appears at the age of 2-3
years and nearly always corrects by the age of 6 years.
It may be associated with flat feet. The degree of
deformity is estimated by measuring the intermalleolar
distance, with the child lying supine, with the knees in
contact. In genu valgum secondary to a disease such as
rickets, there will be findings suggestive of the primary
disease.

6. Treatment
 Spontaneous recovery occurs in most idiopathic cases.
A medial shoe raise (3/16 inch) is sometimes
prescribed. It has no proven scientific rationale but
does help in satisfying anxious parents. It the
intermalleolar distance is 10 cm or more by the age 4,
the child may need an operation. A supracondylar
closed wedge osteotomy is performed.

7. Genuvarum
(Rum– knees
apart)
 This is a condition where the knee are abnormally
divergent (bow like) and ankles abnormally
approximated.

8. Causes
 Idiopathic is the commonest type. In others, causes
similar to those for genu valgum can be identified,
except that the defective growth is on the medial side
of the epiphyseal plate. Blounts’s disease is a special
type of genu varum where the postero-medial part of
the proximal tibial epiphysis fails to grow during the
first 3 years of life.

9. Clinicalfeatures
 An ugly deformity is the main complaint. Severity of
deformity can be estimated by measuring the distance
between the two knees with the ankles held together. If
the distance is more than 8 cm, further investigations
for an underlying cause are required.

10. Treatment
 Idiopathic type usually corrects spontaneously. Shoes
with an outer raise (3/16 inch) are usually prescribed.
If bowing persists beyond childhood, surgical
corrections may be required.

11. Genu
recurvatum
 This means hyperextension at the knee joint. It may be
congenital or acquired. Polio is the commonest cause of
acquired genu recurvatum. Other causes are
i) Diseases known to produce lax ligaments. (Marfan’s
syndrome, Charcot’s arthropy)
ii) Epiphyseal growth defects
iii) Malunited fractures

12. Treatment
 It is difficult. Generally, support with braces is
required. It some cases, upper tibial corrective
osteotomy may be required.

13. Poplitealcyst
 This follows a synovial rupture or its herniation in the
popliteal region. It may be osteoarthritic (Morrant-
Baker’s cyst) or secondary to rheumatoid arthritis.
 The lump is in the midline and fluctant, but is not
tender. It may shrink following knee aspiration if it is
connected to the knee, or may leak or rupture so that
the fluid tracks down the calf. Arthroscopic excision is
the treatment of choice for symptomatic cases not
responding to conservative treatment.

14. Loosebodiesin
joints
 This is a common problem, seen most frequently in the
knee joint. A fractured osteophyte, becoming loose in
an osteoarthritic, is the commonest cause. Other
causes are knee osteochondritis, osteochondral
fractures, synovial chondromatosis, etc. in synovial
chondromatosis, the number of bodies is more than 50-
60. The complaint of the patient with a loose body in
the joint is sudden locking of the joint. Often he can
feel the loose body within the joint. Most loose bodies
are radiopaque and can be seen on plain X-rays. In
some, an arthroscopic examination may be required.
Treatment is removal of the body arthroscopically or by
opening the joint.