Orthopaedics of the knee:

Bow legs and knock knees:

Normally 5-7 degrees of valgus. More genu valgum, less genu varum. Catchy only if: progressive, unilateral, of recent onset.

Gauging:

Genu varum: intercondylar distance of 6cm

Genu valgum: intermalleolar distance of 8cm

Physiologic bow legs and knock knees:

Bow legs normal in babies, knock knees in 4 years olds. Only reassurance and 6 months follow up.

If deformity continues at 10 years, stabling of physis is recommended.

Compensatory deformities:

As result of proximal femur deformities.

Ant-eversion: squinting patellae, genu valgum, tibial torsion, and valgus heels.

Genu varum and valgum in adults:

May be a sequel of childhood deformities, no concern normally unless combined with knee instability= predisposing to OA, in medial compartment or lateral.

Genu valgum may cause mal-tracking of patella leading to OA in patello-femoral joint.

Knee deformities are also common in OA (varum), RA (valgum).

Genu recurvatum (hyperextension deformity):

-Congenital: due to intra-uterine mal-position, recovers spontaneously.

-Lax ligaments: usually they stand with knees back-set, prolonged traction on a frame or hyperextension bracing causes the same.

- paralytic conditions: polyo= equinus at ankle, leading to recurvatum if plantigrade is to be achieved (useful if mild).

Meniscus lesions:

Advantages of menisci:

1- Increase stability and congruence of knee

2- Controls the complex rolling and gliding

3- Load distribution

The menisci are made mainly of circumferential fibres making them difficult to be torn in width (except middle life and after, where fibrillation has taken place).

Pathology:

Medial meniscus mainly (less mobile).

Types of tear: pocket handle (locking).

Anterior horn, posterior tear.

Menisci are avascular except of outer third.

Clinical features:

Yung adult, flexing the knee while taking weight and twisting (grinding twisting).

Swelling occurs a day after, pain localised to knee line.

Investigations:

X-rays: normal

MRI: excellent

Arthroscopy: immediate Rx.

Rx:

Conservative: 3-4 weeks in extension cast

Operative: only if symptoms recurrent and unlockable knee.

Patello-femoral overload syndrome (patellar pain syndrome, chondromalacia of the patella):

Anterior or patello-femoral knee pain

Chondro-malacia is the cause??

Pathology:

Repetitive mechanical overload of the patello-femoral joint due to incongruence of joint or mal-alignment of the extensor mechanism.

Clinical features:

Young adult or girl teenager, anterior knee pain, aggravated by climbing stairs, and standing after prolonged sitting.

Pain due to test.

Rx:

Conservative: vast majority adjustment of stressful activities and pt.

Vastus medialis strengthening.