evised by
Goldthwait consists in exposing, by means of a vertical incision, the
whole length of the patellar ligament, splitting it longitudinally,
separating the lateral half from the tibia, passing it under the
medial portion and suturing it to the periosteum; this gives the
quadriceps a straight line of pull. We have achieved the same result
by dividing the lax capsule and synovial membrane on the medial side
of the patella, and overlapping the edges with a double line of catgut
sutures.

Lateral dislocation of the patella is met with in extreme forms of
_knock-knee_, and after correction of this deformity by osteotomy, and
its possible occurrence should be guarded against at the time of the
operation.

#Genu Recurvatum.#--In this deformity the knee is hyper-extended, the
thigh and leg forming an angle which is open forwards; the attitude
may be permanent or may only appear on walking. It is an extremely
disabling and unsightly deformity.

There are several varieties. In the _congenital form_, which is
apparently due to a faulty attitude of the lower extremities _in
utero_, the patella may be imperfectly developed or absent; the knee
is convex backwards, and attempts to flex the joint cause pain. Other
deformities frequently coexist. The treatment consists in flexing the
joint to a right angle under an anaesthetic, and maintaining this
attitude by means of plaster-of-Paris or splints until the growth of
parts overcomes any tendency to relapse.

_Acquired Forms._--The most common acquired form is the result of
anterior poliomyelitis, and is described in the next section.

The deformity may also be due to rickets which has caused a backward
bend of the tibia immediately below its upper epiphysis--sometimes
combined with an exaggerated forward curve of the femur. If there is
no prospect of spontaneous rectification, the upper end of the tibia
should be divided with the osteotome, and the limb straightened.

It may result also from fracture or from separation of one of the
epiphyses in the region of the knee, or from cicatricial contraction
of the quadriceps. As a result of bone and joint disease, it is met
with chiefly in neuro-arthropathies when the knee has become
disorganised and flail-like.

#Deformities of the Knee resulting from Anterior Poliomyelitis and
from Spastic Paralysis.#--When there is paralysis of all the muscles
acting on the knee, the joint may be so flail-like that the patient is
unable to s