Download Patellofemoral (Kneecap) Realignment

Information for Patients
Patellofemoral
(Kneecap)
Realignment
DMI ref: 1992-07.indd(RP)
Department of Orthopaedic Surgery
Tel: 01473 702107
Issue 1: August 2007
© The Ipswich Hospital NHS Trust, 2007. All rights reserved. Not to be
reproduced in whole, or in part, without the permission of the copyright owner.
Page Further information is also available in the separate Patellofemoral
(Kneecap) Problems booklet.
The patellofemoral joint
The patellofemoral joint of the knee is formed by the kneecap
(patella) moving up and down a smooth groove on the front of the
thigh bone (femur). This groove is called the trochlea.
The moving surfaces of the patella and trochlea are covered with
articular cartilage, which provides a smooth and cushioning joint
surface.
The patella is held within the trochlea by two tendons. The quadriceps
tendon passes upwards from the top of the patella and joins the
quadriceps muscle (the main muscle at the front of the thigh). The
patella tendon passes downwards from the bottom of the patella
and attaches to a bump on the front of the tibia called the tibial
tuberosity.
Why is a patellofemoral realignment performed?
A patellofemoral realignment is performed to correct maltracking of
the patella. Maltracking occurs when the patella does not glide evenly
within its groove. This produces pain, clicking and sometimes the knee
gives way. Patellar maltracking is also known as patellar subluxation.
The most extreme form of maltracking is a dislocation. In a dislocation
the patella comes out of its groove completely. This can either be due
to an injury or it can happen spontaneously. In some people further
episodes of dislocation can happen (known as recurrent dislocation).
Page What causes patellar maltracking?
Certain features can alter the normal mechanics of the knee:
• Weakness of the quadriceps muscle
• A high patella
• A lateral (off-centre) tibial tuberosity
• Stretched medial tissues (the capsule and ligaments on the inner
side of the knee)
• Tight lateral tissues (the capsule on the outer side of the knee)
Who should consider a patellofemoral realignment?
The following patients may be suitable for a patellofemoral
realignment operation:
• Patients who have had recurrent (repeated) dislocations of the
patella.
• Patients who have subluxation of the patella (maltracking of the
patella which makes the knee give way)
• Patients who have anterior knee pain with maltracking
Surgery is not indicated for anterior knee pain with normal patella
tracking.
What are the alternatives to a patellofemoral
realignment?
The surgical and non-surgical alternatives are described in our
separate booklet Patellofemoral (Kneecap) Problems.
Page What is a patellofemoral realignment?
A patellofemoral realignment operation involves some or all of the
following:
1 A ‘lateral release’ of the tight capsule on the outer side of the
patella.
2 The tibial tuberosity may be moved sideways, downwards and
forwards as needed (known as a TT transfer). The tuberosity is
then fixed in its new position with a screw.
3 A ‘VMO advancement’ is performed to move the inner part of the
quadriceps muscle across the patella to improve its mechanical
efficiency. Alternatively, a MPFL reconstruction may be performed
to replace the ligament which is commonly torn when the patella
dislocates.
4 Patella chondroplasty: any rough areas of joint surface are shaved
smooth.
Rarely, a trochleaplasty is performed to deepen an abnormally shallow
trochlea groove.
Following a patellofemoral realignment operation, the recovery takes
several months and a specific rehabilitation programme will need
to be followed. If a TT transfer has been performed then the screw
fixation will need to be protected by limiting knee movement in a
knee brace.
A diagram illustrating the various steps
involved in a patellofemoral realignment
operation.
TT = tibial tuberosity.
VMO = inner part of the quadriceps muscle.
Page What are the benefits of having a patellofemoral
realignment?
1 A stable knee. The patella tracks more normally and should not
dislocate.
2 Less pain. A patella that tracks more normally is likely to be less
painful, although some pain may persist, depending on the extent
of any damage that has already happened.
A patellofemoral realignment operation is generally a very successful
operation in preventing further dislocation of the patella: 95% (or 19
out of 20 patients) will never dislocate again.
Patients with anterior knee pain and maltracking typically have a 75%
chance of a good outcome. In other words, three out of four patients
have good relief of their symptoms of anterior knee pain and giving
way.
Your surgeon will discuss your injury and the treatment options with
you. However it is your decision whether or not to have surgery.
What are the risks of having a patellofemoral
realignment?
Some of the risks are listed below. Although there seem to be a large
number of possible risks, the chance of a significant problem is less
than 10% (one patient in 10).
Medical problems
The risk of developing a major illness, such as a chest infection, is
uncommon after a patellofemoral realignment.
Blood clots (DVT and PE)
Following surgery to the legs blood clots can form in the deep veins
of the calf or thigh (deep vein thrombosis or DVT). This usually
causes pain and swelling in the calf or thigh. Occasionally part of
the blood clot can break free and travel in the bloodstream to the
lungs (a pulmonary embolism or PE). A PE can be life threatening but
fortunately this is extremely rare after a patellofemoral realignment.
Page Infection
A wound infection may occur but usually responds to antibiotics. A
more serious infection within the knee joint is rare (less than one in
400).
Bleeding
Some bleeding occurs after any operation. Occasionally a deep
collection of blood (called a haematoma) may persist. This usually
responds to ice and physiotherapy.
Nerve injury
A patch of numbness around the scars is usual. The numb area tends
to shrink with time.
Metalwork irritation
Usually the screw used to fix the tibial tuberosity is left in
permanently. However, if it is uncomfortable it can be removed.
Kneeling discomfort
Some tenderness of the scar can cause persistent discomfort on
kneeling.
Stiffness
Over the first few months after surgery it requires hard work and
commitment to maximise the movement you gain from your new
knee. Moving the tibial tuberosity downwards can tighten the
quadriceps muscle and mean that it may be difficult to bend the knee
fully. Occasionally the knee can remain stiff. This may be due to excess
scarring within the knee, which may require a further operation.
Osteoarthritis
Some patients develop osteoarthritis (arthritis due to ‘wear and
tear’) after a patellofemoral realignment. Usually this is the result of
damage to the joint surfaces sustained before the operation.
Page What does a patellofemoral realignment operation
involve?
Before the operation
It is advisable to continue a non-operative treatment programme
(such as straight leg raises, hamstring stretches, weight loss, etc) as this
can help keep your symptoms under control and also help speed up
your recovery following the operation.
Further details about a non-operative treatment programme are in
our separate booklet Patellofemoral (Kneecap) Problems.
The operation
Usually you will be admitted on the morning of the operation. The
operation may be performed under general anaesthesia (when you
are fully asleep) or occasionally spinal anaesthesia (an injection of
local anaesthetic into the back leads to numbness of the legs). Your
anaesthetist will discuss the exact type of anaesthetic with you when
you are admitted to hospital.
The operation itself lasts about 1-2 hours. Including preparation and
recovery, you will be away from the ward for at least three hours.
Recovery in hospital
Physiotherapy is started as soon as possible after you have recovered
from the anaesthetic. If your tibial tuberosity has been moved, you
will be fitted with a brace that restricts how far you can bend your
knee. The brace will protect the tibial tuberosity until it has healed
in its new position (this usually takes 6-8 weeks). Usually the range of
movement allowed by the brace will be gradually increased over the
weeks. You may also need crutches to help you walk. Most patients
will be able to go home within 2-3 days.
The wound may be closed with surgical clips or stitched with an
absorbable or non-absorbable stitch. The ward nurses will give you
advice about your wound before you go home.
Page After leaving hospital
The discomfort of the operation settles steadily but you may need
to continue with pain relief medication for a few weeks. Initially it is
normal to have some swelling, bruising and weakness of the leg.
The end result depends greatly on your rehabilitation after the
operation. You will need to work hard on both regaining the full
movement of the knee and building up the strength of the muscles.
Your physiotherapist will guide you through a specific rehabilitation
programme. The following is a guideline:
• First six weeks. Initially you may need crutches to walk. Applying an
ice pack for short periods will help reduce any swelling. If you have
been fitted with a brace this will restrict how far you can bend your
knee. Usually the range of movement allowed by the brace will be
gradually increased over 6-8 weeks and you should aim to regain as
much movement as the brace will allow. Quadriceps strengthening
exercises will be started.
• 6-12 weeks. You should be reviewed in the outpatient clinic 6-8
weeks after the operation. If you have been fitted with a brace,
you will be allowed to stop wearing this once your surgeon has
checked on your x-rays that the tibial tuberosity has healed well.
You can then work on regaining a full range of motion and walking
normally. You will also start further strengthening exercises.
• 12 weeks – six months. Agility work and low-risk sporting activity
can begin. Later on you may start sport-specific exercises.
Return to work
Office workers may be able to return to work after 1-2 weeks. Return to
other forms of work should be discussed with your surgeon.
Return to driving
You may return to driving when it is comfortable and safe. If the
right knee has been reconstructed, you must be able to walk without
crutches and you must be able to stamp hard on the brake pedal
without flinching so that you can perform a safe emergency stop if
needed.
Page Return to sport
You should make a gradual return to full training and competitive
sport only when your strength, range of motion and coordination
have recovered fully.
Your surgeon may recommend some restrictions to your sporting
activity. For example, if significant damage to the joint surfaces is seen
at the time of surgery, you may be advised to minimise any repetitive
weight-bearing involving bending and straightening of the knee (such
as running uphill, stair-climbing, stepping exercises).
X-rays (side views) of a knee before and after a successful
patellofemoral realignment operation.
Before the operation (left) the patella is higher than normal.
After the operation (right) a fixation screw can be seen. This is fixing
the tibial tuberosity, which has been moved downwards to lower the
position of the patella.
Page 10
Further information
If you have any queries, please contact your consultant’s secretary.
If you have any concerns during your recovery after a patellofemoral
realignment operation, please contact your consultant’s secretary or
the ward on which you stayed. They may be contacted via the hospital
switchboard on 01473 712233.
Page 11
Produced by:
The Ipswich Hospital NHS Trust
Heath Road, Ipswich, Suffolk IP4 5PD
Hospital switchboard: 01473 712233
www.ipswichhospital.nhs.uk