MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
Anteromedial parapatellar approach1,2
(ii) Surgical approaches
to the knee joint
Indications
Total knee arthroplasty (standard approach), exploration of knee
joint, drainage of sepsis, synovectomy.
Jeremy ES Stanton
Structures at risk
Infrapatellar branch of saphenous nerve, patellar tendon.
Chinmay M Gupte
Vishy Mahadevan
Approach
The patient is positioned supine on the table to allow free flexion
and extension of the knee. A lateral side-support is used in
conjunction with a padded bar or bolster placed where the foot
will lie when the knee is flexed. A tourniquet (if used) is placed
around the thigh above the operative field.
A longitudinal, anterior midline skin incision is commenced 6
cm proximal to the superior border of the patella, and carried
distally to the level of the tibial tubercle.
The midline incision is deepened along its length through
the subcutaneous fat and pre-patellar bursa to the level of
the fascia overlying the patellar tendon, patella and quadriceps tendon. Soft tissue flaps are raised laterally and
medially by dissection to the lateral and medial borders of the
patella.
A medial parapatellar arthrotomy is performed (Figure 1).
An incision is made just superior to the patella at the junction
of the medial one-third and lateral two-thirds of the quadriceps
tendon. The incision is extended proximally in the line of the
tendons of rectus femoris and vastus intermedius to make use
of the skin incision. Distally, the arthrotomy incision parallels
the medial border of the patella, preserving a 10 mm cuff of
capsule on the medial edge of the patella to facilitate closure at
the end of the procedure. At the junction of the proximal twothirds and distal one-third of the patella, the incision follows
a gentle curve towards the midline and continues along the
medial border of the patellar tendon to the level of the tibial
tubercle.
In surgery for arthroplasty, a limited medial release can aid
access to the knee joint. The anterior horn of the medial
meniscus is divided from its intercondylar attachment and
reflected medially. The inferior fibres of the medial retinaculum
are then dissected from the anteromedial surface of the tibia.
With the knee in extension the patella is everted laterally. With
the patella held laterally, the knee is gently flexed, thereby
exposing the knee joint.
Accidental avulsion of the patellar tendon from the tibial
tubercle is difficult to repair. If this attachment is threatened it
is better to detach the patellar tendon with an underlying block
of bone3 (Figure 2). In knee arthroplasty surgery, reattachment
of the bone block may be compromised by the tibial implant.
An alternative is a quadriceps turndown.4 The quadriceps
tendon is incised in an inverted ‘v’ (i.e. L) orientation
(Figure 3).
Abstract
There are various surgical approaches to the knee joint and its
surrounding structures, and such approaches are generally designed to
allow the best access to an area of pathology whilst safeguarding important surrounding structures. In this article we provide a concise account of
the commonly used approaches to the knee joint. Many knee procedures
nowadays are routinely performed via arthroscopic or arthroscopic assisted methods. However, knowledge of open surgical access to the knee
remains vital for knee arthroplasty surgery and cases where arthroscopy
is not possible or practical.
Keywords approach; arthroplasty; knee; surgery
Introduction
Notwithstanding the many advances in arthroscopic knee
surgery and the ever expanding list of surgical conditions of the
knee that can be treated arthroscopically, there are several clinical situations where arthroscopic approaches may be inadvisable, unfeasible or even frankly contraindicated. Thus,
familiarity with the surgical anatomy and technical steps
involved in a certain number of ‘open’ surgical approaches
should be deemed essential, and these approaches should be
a mandatory part of the surgeon’s repertoire.
In this article it is our aim to present a concise description of
the steps and anatomical sequences involved in the execution of
each of a select number of key surgical approaches to the knee. It
is our view that this list of approaches is sufficiently wideranging to take account of most clinical situations.
As a general rule, longitudinal, extensile incisions are recommended. Transverse incisions should be avoided in the knee
region. Furthermore, in the elderly, in those with longstanding
significant arthritis and in those with chronic peripheral vascular
insufficiency, great caution must be exercised during skin
mobilization.
Jeremy ES Stanton MRCS MB ChB Registrar Orthopaedics, Guy’s St
Thomas’ NHS Trust, London, UK.
Chinmay M Gupte PhD FRCS (Tr & Orth) MA (Oxon) MRCS BM BCh Consultant,
Guy’s St Thomas’ NHS Trust, London, UK.
Sub-vastus approach5
A shorter midline incision is performed. A transverse arthrotomy is made at the mid-patellar level (Figure 4). The lower
fibres of vastus medialis are bluntly dissected from the retinaculum before the capsule is incised. Enthusiasts of this approach
Vishy Mahadevan PhD FRCS(Ed) FRCS Professor of Surgical Anatomy and
Barbers’ Company Reader in Anatomy, Raven Department of Education,
The Royal College of Surgeons of England, London, UK.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
Figure 1 Medial parapatellar arthrotomy.
Figure 3 Quadriceps turndown.
claim to have less intra-operative blood loss and more rapid
rehabilitation following total knee arthroplasty.6 However,
exposure of the joint is somewhat restricted in this approach, as
is adequate eversion of the patella. A Cochrane meta-analysis is
currently underway to evaluate surgical approaches in knee
arthroplasty.7
Anterolateral parapatellar approach9,10
Indications
Total knee arthroplasty in the valgus knee, exploration of knee
joint.
Structures at risk
Superior lateral genicular artery, patellar tendon.
Mid-vastus approach8
Similar to sub-vastus technique, blunt dissection is performed
through the muscle of vastus medialis itself to facilitate
exposure.
Approach
The patient is positioned supine on the table to allow free flexion
and extension of the knee. A lateral side-support is used in
Figure 2 Patellar tendonetibial tuberosity osteotomy.
ORTHOPAEDICS AND TRAUMA 24:2
Figure 4 Sub-vastus arthrotomy.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
conjunction with a padded bar or bolster placed where the foot is
likely to lie when the knee is flexed. A tourniquet (if used) is placed
around the upper thigh, well proximal to the operative field.
The skin is incised longitudinally in the midline; the incision
commencing 6 cm proximal to the upper border of the patella
and extending distally to the level of the tibial tubercle.
The midline incision is deepened along its length through the
subcutaneous fat and pre-patellar bursa to the level of the fascia
overlying the patellar tendon, patella and quadriceps tendon. Soft
tissue flaps are raised laterally and medially by dissection to the
lateral and medial borders of the patella.
A lateral parapatellar arthrotomy is performed. An incision is
made just superior to the patella along the lateral border of the
quadriceps tendon. The incision is extended proximally in the
line of the tendons of rectus femoris and vastus intermedius to
make use of the skin incision. Distally, the arthrotomy follows
the lateral border of the patella; a cuff of capsule being preserved
for closure. At the junction of the proximal two-thirds and distal
one-third of the patella the incision follows a gentle curve
towards the midline and continues along the lateral border of the
patellar tendon to the level of the tibial tubercle.
With the knee in extension the patella is everted medially.
With the patella held medially, the knee is gently flexed, thereby
exposing the knee joint.
Figure 5 Medial arthrotomy.
Limited medial approach (meniscus)11
Medial approach4,11
Indications
Open meniscal repair or resection.
Indications
Medial collateral ligament repair/reconstruction, access to
medial meniscus.
Structures at risk
Medial meniscus, medial collateral ligament, infrapatellar branch
of saphenous nerve.
Structures at risk
Infrapatellar branch of saphenous nerve, medial meniscus, long
saphenous vein.
Approach
The patient is positioned supine so that the knee can be flexed
over a bolster held in a foam gutter. Our preferred method is to
flex the knee over the edge of the operating table with the foot
resting in the lap of the operating surgeon.
The skin incision is started at the level of the middle of the
patella at the medial edge. The incision runs obliquely in an
inferomedial direction to a point 1 cm distal to the joint line
(Figure 5). The approach is deepened in line with the skin incision down to the level of the medial patellar retinaculum. A
medial arthrotomy is formed above the level of the joint line. The
patellar retinaculum is divided in line with its fibres and the
underlying synovium is divided. The arthrotomy is then
extended proximally and distally under direct vision so as to
avoid accidental damage to the femoral condyle cartilage, medial
meniscus and coronary ligament.
To access the posterior portion of the medial meniscus,
a second incision may be required positioned posterior to the
medial co-lateral ligament. A blunt clip is passed through the
anterior arthrotomy and is advanced along the inside of the joint
capsule towards the posterior aspect of the knee. The posterior
edge of the medial collateral ligament is identified by palpation
with the clip. Once identified, an incision is made in the skin in
line with the posterior edge of the collateral ligament. The incision is deepened to the joint capsule, which is incised.
Approach
The patient is positioned supine and the operated leg is placed in
the so-called ‘Figure 4’ position. The hip is externally rotated, the
knee flexed to 60 degrees, and the foot is rested on the contralateral shin.
The skin incision is started just anterior and proximal to the
adductor tubercle of the medial femoral condyle (Figure 6). The
incision is curved anteroinferiorly, running over the femoral
condyle and down along the proximal tibia. The middle third of
the skin incision lies parallel with the patella and the distal
portion runs in line with the tibia.
The incision is deepened along its length down to the fascia.
Soft tissue flaps are raised anterior towards the patella and
posterior towards the posteromedial corner. The infrapatellar
branches of the saphenous nerve cross the inferior aspect of the
incision and are sacrificed. The saphenous nerve itself should be
preserved along with the long saphenous vein. The deep fascia is
incised along the anterior edge of the sartorius muscle (Figure 7).
The sartorius muscle is best identified near its insertion into the
tibia at the pes anserinus; the incision should be started here and
continued superiorly in line with its fibres. The knee is flexed,
allowing posterior retraction of the sartorius to reveal the semitendinosus and gracilis tendons. Retraction of all three muscles
allows visualization of the tibial insertion of the medial collateral
ligament (Figure 8). The femoral insertion of the medial
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
Figure 8 Deep structures medial approach.
the medial collateral ligament. The arthrotomy is begun away
from the joint line to avoid inadvertent damage to the posterior
horn of the medial meniscus.
Figure 6 Skin incision medial approach.
collateral ligament is exposed by anterior retraction of the fascia
and vastus medialis muscle while extending the knee.
The anterior aspect of the knee joint is accessed via an incision of the medial patellar retinaculum. As previously described,
the incision runs inferior and medial from a point just medial to
the mid-portion of the patella to the joint line between the vastus
medialis muscle and the medial border of the anterior fat pad.
The posteromedial joint capsule lies posterior to the medial
collateral ligament. Further exposure is possible to almost the
midline posteriorly. The medial head of gastrocnemius is separated from semimembranosus. With the knee fully flexed the
medial gastrocnemius may be dissected away from the posteromedial capsule.
The posterior aspect of the knee joint may be accessed via an
arthrotomy just posterior and parallel to the posterior border of
Limited lateral approach (meniscus)11
Indications
Open meniscal repair or resection.
Structures at risk
Lateral inferior genicular artery, lateral meniscus, lateral collateral ligament.
Approach
The patient is positioned supine, with the operated leg hanging
over the side or end of the table.
The skin incision is started with the knee flexed at 90
degrees, from the lateral border of the mid-point of the patella.
The incision is extended in an oblique line distally and laterally.
The skin incision just crosses the joint line but does not cross
over the lateral collateral ligament (Figure 9). The incision is
deepened down to and through the lateral patellar retinaculum,
in the line of the skin incision. The knee joint is entered above
the joint line initially and then the arthrotomy is extended under
direct vision. This measure avoids accidental damage to the
lateral meniscus.
This oblique incision offers a limited view of the back of the
knee. An improved view is obtained by flexing the knee past 90
degrees. An alternative is to fully extend the knee and apply
a varus force across the joint.
Lateral approach4,11
Indications
Exploration of lateral collateral ligament and posterolateral
corner, access to anterior and posterior intra-articular structures.
Structures at risk
Lateral superior and inferior genicular arteries, common peroneal
nerve, lateral collateral ligament, popliteus tendon, lateral
meniscus.
Figure 7 Superficial dissection medial approach.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
The incision is deepened in the line of the skin incision down
to the deep fascia. Soft tissue flaps are raised anterior to the
patella and posterior to the mid-point of the biceps femoris
tendon. The common peroneal nerve runs on the posterior
border of the biceps femoris tendon. The deep fascia is divided
along the interval between the biceps femoris and the iliotibial
band (Figure 11). The iliotibial band is retracted anteriorly and
the biceps femoris is retracted posteriorly, to reveal the lateral
collateral ligament running from the lateral femoral condyle to
the fibular head.
The posterior lateral joint may be accessed by an arthrotomy
performed between the lateral collateral ligament and lateral
head of gastrocnemius; the capsule is incised in the direction of
the lateral collateral ligament (Figure 12). The capsule should be
entered well above the joint line so as to avoid accidental damage
to the lateral meniscus and popliteus tendon, running deep to the
capsule and superficial to the meniscus. The lateral inferior
genicular artery runs between the lateral head of gastrocnemius
and the joint capsule at the level of the tibial plateau. It may be
encountered when extending the posterolateral arthrotomy and
should be ligated.
The anterior joint may also be accessed via this lateral
approach. A separate anterior arthrotomy is performed just
lateral and parallel to the patella tendon (Figure 11).
Figure 9 Lateral arthrotomy.
Approach
The patient is positioned supine on the operating table;
a sandbag under the buttock of the operated side will help
internally rotate the femur. The knee is flexed to 90 degrees.
The incision is begun laterally in line with the femur and
curves around the knee to run in line with the tibia. The midportion of the incision runs parallel with the patella. The incision crosses the joint line at the level of Gerdy’s tubercle and
continues in line with the tibia (Figure 10).
Posterior approach4,11
Indications
Exploration of the popliteal fossa and neurovascular structures,
repair of posterior cruciate ligament avulsion fracture, excision of
popliteal cysts.
Structures at risk
Popliteal artery and veins, long and short saphenous veins, sural
nerve, common peroneal nerve, tibial nerve, medial and lateral
genicular vessels.
Figure 10 Skin incision lateral approach.
ORTHOPAEDICS AND TRAUMA 24:2
Figure 11 Superficial dissection lateral approach.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
The approach is deepened down to the deep fascia. Soft tissue
flaps are raised proximally and distally. The short saphenous
nerve perforates the deep fascia close to the midline, distal to the
popliteal fossa. The vein is readily identified if the leg has not
been fully exsanguinated prior to tourniquet insufflation. The
medial sural cutaneous nerve runs just lateral to the vein and
should be preserved.
The deep fascia is incised lateral to the short saphenous vein
and divided in the midline up to the proximal part of the exposure. The medial sural nerve is dissected from distal to proximal
as it lies with the short saphenous vein between the medial and
lateral heads of the gastrocnemius muscle (Figure 14). The sural
nerve runs deep in the popliteal fossa to join the tibial nerve. The
tibial nerve is dissected superiorly to the apex of the popliteal
fossa. The apex is formed by the semimembranosus and biceps
femoris muscles. At the apex, the common peroneal nerve
divides from the tibial nerve to run distolaterally, just medial to
the tendon of biceps femoris muscle. The common peroneal
nerve is dissected free from the biceps femoris to allow later
retraction of the muscle without crushing the nerve.
The popliteal artery and vein lie medial to the tibial nerve
within the popliteal fossa. The artery gives paired branches of
superior and inferior genicular arteries and a single middle genicular artery. The popliteal vein lies posterolateral to the artery at
the apex of the popliteal fossa and crosses the artery as it runs
distally to lie on the medial side (Figure 15). At the base of the
popliteal fossa both artery and vein pass deep to the tibial nerve
from medial to lateral.
The posterior capsule of the knee is exposed by retraction of
the muscles that form the borders of the popliteal fossa. Further
exposure of the posteromedial capsule is gained by dividing the
medial head of gastrocnemius at its insertion onto the femur. The
muscle is then retracted laterally to expose the joint capsule
while protecting the nerve and vessels. The posterolateral
capsule is exposed by separating the lateral head of gastrocnemius from the biceps femoris and dividing its attachment to the
Figure 12 Deep dissection lateral approach.
Approach
The patient is positioned prone on the table.
The skin is incised in a gentle curve from lateral to medial
across the popliteal fossa. The incision begins over the biceps
femoris muscle laterally, and then extends inferomedially to run
obliquely over the popliteal fossa. The incision curves inferiorly
to run over the medial head of gastrocnemius and distal over the
calf (Figure 13).
Figure 13 Skin incision posterior approach.
ORTHOPAEDICS AND TRAUMA 24:2
Figure 14 Posterior dissection through deep fascia.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
Figure 15 Deep posterior dissection of neurovascular structures.
Figure 16 ‘Over the top’ approach to distal femur.
femur. The muscle is then retracted medially, protecting the
nerve and vessels, to expose the joint capsule.
Approach
Based on medial and lateral oblique arthrotomy approaches, as
described above. The patella is retracted rather than everted.
Special retractors are required. These approaches are used in unicondylar arthroplasty.
Lateral approach to distal femur (over the top)11
Indications
Open anterior cruciate reconstruction, used in conjunction with
a medial arthrotomy.
Arthroscopy portals
Indications
Access to medial, lateral and posterior intra-articular structures.
Structures at risk
Lateral superior genicular artery, popliteal artery.
Structures at risk
Menisci, articular cartilage, anterior cruciate ligament.
Approach
The patient is positioned supine, with the knee flexed over
a sandbag.
The skin is incised overlying and in line with the anterior
border of the iliotibial band. The incision is deepened through
the subcutaneous fat and fascia. The deep fascia is divided just
anterior to the iliotibial band. A plane is developed between the
vastus lateralis muscle and the lateral intermuscular septum;
branches of the superior lateral genicular artery should be
identified and ligated or coagulated (Figure 16). The periosteum
over the lateral femur is divided and elevated in a posteroinferior
direction. Blunt dissection is continued using a large curved clip
until the posterior intercondylar notch is entered (Figure 16).
During blunt dissection, the knee should be flexed to allow the
posterior capsule and vessels to fall away from the posterior
femur. The tip of the clip can be viewed in the femoral notch via
a medial arthrotomy.
Approach
Anterolateral: just below the angle of the lateral border of the
patellar tendon and patella (Figure 17). Performed ‘blind’
Minimally invasive surgery for knee arthroplasty12
Indications
Knee arthroplasty.
Structures at risk
As for medial parapatellar approach.
ORTHOPAEDICS AND TRAUMA 24:2
Figure 17 Arthroscopy portals: 1 e antrolateral, 2 e anteromedial, 3 e
superolateral.
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MINI-SYMPOSIUM: SOFT TISSUE SURGERY IN THE KNEE
Superolateral: commonly used as a drainage portal (Figure 17).
Allows visualization of the superior pole of the patella and
patellar tracking in the trochlea.
Posteromedial: after location of the optimal portal sight by
a needle, a stab incision is made in the skin over the palpable
posterior superior edge of the medial femoral condyle
(Figure 18). Used for access to the posterior tibia during posterior
cruciate ligament reconstruction.
A
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4 Abbott LC, Carpenter WF. Surgical approaches to the knee joint.
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12 Pagnano MW. MIS total knee arthroplasty with a subvastus approach.
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Figure 18 Posteromedial arthroscopy portal.
through a stab incision using a pointed scalpel blade. Arthroscopy sleeve is inserted over blunt trocar. Primarily used for
arthroscopy camera access. The position of this portal may be
subtly altered to suit the procedure e.g. a more proximal and
medial portal is often used in anterior cruciate ligament reconstruction to provide an optimal view of the lateral femoral notch.
The anterior arthroscopic portals should be positioned to avoid
unnecessary damage to the anterior fat pad (of Hoffa). This
structure lies deep to the patella tendon and is widest at the
insertion of the patellar tendon onto the tibia. The fat pad is well
innervated and has been shown to be one of the greatest sources
of pain during arthroscopic stimulation.13
Anteromedial: medial to the patellar tendon and above the
medial meniscus (Figure 17). Performed under arthroscopic
vision, a 16-gauge needle is inserted perpendicular to the skin
and observed entering the knee joint. The needle may be repositioned to the desired entry point into the joint capsule. The
needle is removed and a stab incision made in the direction of the
needle. The scalpel blade is arthroscopically observed entering
the knee joint, to avoid accidental damage to cartilage. Usually
used for instrument access to the knee. The exact positioning of
the anteromedial portal is dictated by the access desired. A more
medial portal will provide better instrument access to the lateral
compartment. A more inferior and lateral portal will give better
access to the femoral notch.
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