ACL-Restoration with Semitendinosus Tendon
Commented Step-by-step Illustrations
Main text: Operative Technique | Back to the title page
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- Preparation and Positioning of the Patient
- Fig: Positioning with Knee-joint at 100°
(14KB)
The leg part of the operating table remains extended. The knee is flexed to 100° and the
foot is supported by a roll fixed to the table. No special leg-holder is required and no
tourniquet is used.
- Fig: Positioning with Knee-joint at 140°
(17KB)
The knee-joint can be fully flexed to about 140° and stabilized in this position by the
roll in front of the toes and the lateral abduction post. The full amount of flexion
allows safe placement of the femoral socket close to the "over the top
position".
- Fig: Marking of Skin Incisions (12KB)
Arthroscopy portals and skin incisions are marked on the skin with a marking pen. A 2 cm
long transverse high medial parapatellar incision lies approximately 1 cm distal to the
superior patellar pole and is centered over the medial border of the patella. The whole
procedure can be performed without a tourniquet if the incisions and the knee-joint are
infiltrated with epinephrine / buivacain solution.
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- Graft-Harvest
- Fig: Skin Incision for the Semi-T Harvest (in preparation)
The leg is externally rotated and the knee-joint flexed to 80°. The skin is incised 2 cm
distally and 1 cm medially to the tibial tuberosity along Langer's lines approximately 4
cm in length. The incision should be centered over the inferior part of the pes anserine,
whose superior margin often can be palpated fairly distinctly underneath the skin. The
most superficial layer of the pes anserine, the thin fascia of the sartorius muscle, is
opened in line with the skin incision. The gracilis- and semitendinosus-tendon can be
identified by palpation as they separate and pass over the postero-medial border of the
tibia.
- Fig: Opening of the Sartorius Fascia
(15KB)
The Sartorius Fascia is incised without damaging to the underlying structure
- Fig: Hamstring tendon (10KB)
The more inferior of the two tendons, the Semitendinosus-tendon, is delivered from the
posterior part of the incision using a tendon hook. The tendon is further liberated using
closed Metzenbaum scissors.
- Fig: Detachment of Semi-T Tendon (10KB)
All tendinous slips to the fascia of the medial Gastrocnemius muscle have to be identified
and transected.
- Fig: Insertion of the Tendon Stripper
(8KB)
The tendon is pulled as far as possible out of the wound and an open ended tendon stripper
is attached to the tendon proximally to all tendon slips.
- Fig: Stripping of the Semi-T (8KB)
With slight oscillating motions the tendon stripper is advanced to about 17 cm of length
and the tendon is transected.
- Fig: Cleaning of Soft-Tissue (8KB)
The distally still attached tendon can be freed from soft-tissues using the blade of large
scissors.
- Fig: Tendon Suture (5KB)
The free end of the tendon is captured with a large resorbable suture using a modified
Bunnel stitch (fishing hook). The needle is left attached to the suture for later use.
- Fig: Bony Trough for Bone Plug Harvest (in preparation)
To allow the later insertion of the graft into the knee-joint, the Semitendinosus tendon
is harvested with a small bone plug attached from its distal insertion into the tibia. A
specially designed chisel, which is shaped like a pyramid, is used exactly at the tendon
attachment site to indent the cortical bone in order to make a small trough.
- Fig: Harvest of the Bone Plug (13KB)
The 10 mm Helical Tube Saw (HTS)-Osteotom (KaltecŪ, Edwardstown, South Australia) is fed
around the tightly held tendon. The surgeon stabilizes the osteotom in the bony trough
with his fingers. Using light oscillating motions a small bone plug is harvested
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- Graft-Preparation
- Fig: The Harvested Semi-T Tendon (11KB)
The harvested Semi-T tendon and the attached bone plug have an approximate length of 22
cm.
- Fig: Predrilling of the Bone Plug (10KB)
The bone plug is pierced using a 1.5 mm drill-bit. Drilling is facilitated by the use of
the drill-guide-clamp. If the bone plug is fairly short one should insert the K-wire
obliquely to the long axis into the cortical bone of the plug.
- Fig: Insertion of a Threaded K-Wire (in preparation)
A threaded 2 mm K-wire is inserted into the bone plug. It is imperative that the K-wire
sits well in order to achieve later a successful graft passage into the joint.
- Fig: Folding the Tendon (12KB)
A threaded 2 mm K-wire is inserted into the bone plug. It is imperative that the K-wire
sits well in order to achieve later a successful graft passage into the joint. After
folding the tendon, the free end is passed through a small cut near the bone plug
- Fig: Fixation of Tendon to Bone Plug (4KB)
The smooth end of the K-wire (the bone plug is on the threaded end) is slightly bent and
fixed tightly into the 2 mm hole of the working station. The tendon is folded to one third
of its original length and is placed in such a manner over the top of the bone plug that
the free end of the tendon is approximately 5 mm shorter than the tendinous sling. In this
position the tendon is secured to the bone plug using a 3-0 resorbable suture.
- Fig: Preparation of Tendon End (in preparation)
The previously attached suture of the free end of the tendon is pierced through the axilla
of the tendon loop. That way the free end of the tendon will rest inside the tendon loop
which itself is secured with a large non-absorbable suture (SyntofilŪ).
- Fig: Baseball-Stich of Tendon (4KB)
Both holding sutures are pulled around the hook at the end of the working station. They
are tensioned so that the K-wire bends in a curve. There is approximately a 45° angle
between the bony end and the tendinous part of the graft. In this position the sutures are
clamped together. Using a baseball stitch and absorbable suture material the three tendon
strands are sewn to each other at the area where they will be held with the interference
screw inside the femoral socket.
- Fig: Diameter of the bony end of the graft (in preparation)
The length and the diameter of the graft is checked using the sizing holes of the working
station. The diameter at the bony end should be 10 mm.
- Fig: Diameter the free end of the graft (4KB)
The diameter of the free end should be 8 mm.
- Fig: Length of the graft (14KB)
The length of the graft should now be about 70 mm. The graft is covered with a moist
sponge and stored until its insertion inside the groove of the working bench.
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- Debridement and Notch-Plasty
- Fig: Debridement of old ACL (in preparation)
Via the low medial working portal just above the joint line all remnants of the old ACL
are removed. The femoral as well as the tibial attachments of the old ACL should be
cleaned of all soft-tissues. Often one has to remove additional hypertrophic hoffa flaps
in order to visualize clearly the future site of the tibial socket. If the view to the
posterior part of the notch is insufficient, one should remove 2 or 3 mm of bone from the
lateral wall.
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- Femoral Socket
- Fig: Femoral Pilot-Hole (6KB)
With the knee bent to 100° one can palpate the posterior cortical border of the notch
using an angled bone pick. The tool is pulled 5 mm forward and a pilot hole is made in the
left knee at 1-2 O'clock and in the right at 10-11 O'clock. In this way only approximately
2 mm of bony bridge will remain posteriorly.
- Fig: Completion of Pilot Hole (10KB)
The knee-joint is now fully bent to 140° and the foot is placed on the table in front of
the roll. By fully flexing the knee joint the pilot hole is well visualized without
hindrance by the so-called resident's ridge. The Synos screwdriver should be used turning
counterclockwise to penetrate the cancellous bone.
- Fig: Creation of Femoral Socket (10KB)
The 7 mm femoral dilator is pushed into the bone using a mallet. The blade of the dilator
should be held vertically in order to allow the blade to be deviated anteriorly and not to
penetrate the hard posterior wall. Once the 40 mm long dilator is fully inserted, an
oscillating motion of the dilator will create a cylindrical hole.
- Fig: Enlargement of Femoral Socket (in preparation)
The correct shape and depth of the socket can be verified using a 7 mm sizer. Depending on
the previously measured cross section of the graft, the socket may have to be enlarged to
8 or 9 mm.
- Fig: Femoral Screw Hole (in preparation)
At the superior border of the entrance of the socket a small indentation is created using
the screw notcher. This indentation will later prevent the screw from accidentally
rotating around the graft during screw insertion.
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- Tibial Socket
- Fig: Entrance of Tibial Socket (arthroscopy)
(10KB)
The angled pick is introduced through the anteromedial arthroscopy portal. In different
angles of extension under direct arthroscopic vision the center of the future tibial
socket is determined.
- Fig: Entrance of Tibial Socket (tibial plateau)
(8KB)
The center of the socket should lie in the postero-medial aspect of the original ACL were
it intercepts a line drawn from the posterior border of the anterior horn of the lateral
meniscus to the medial tibial spine. This point should also be as medial as possible so
the graft will cross the notch in front of the posterior cruciate ligament.
- Fig: Entrance of Tibial Socket (marking)
(6KB)
Again the entrance of the tibial socket is checked in different angles of extension and
under direct vision. A marking hole is made at the ideal location.
- Fig: Medial Parapatellar Skin Insion (in preparation)
With the knee joint bent to 100° a 4 cm long vertical skin incision is made just at the
medial border of the patella and 1 cm distal to the superior patellar pole. The skin is
mobilized subcutaneously and 10 mm of the underlying capsule is opened in line with the
skin incision.
- Fig: Tibial Pilot-Hole (7KB)
The SysorbŪ screw driver is inserted from above into the medial parapatellar incision and
pushed into the previously made marking hole of the tibia as parallel as possible to the
long axis of the tibia.
- Fig: Creation of Tibial Socket (8KB)
The hole is enlarged to 9 mm width and 20 mm depth using the sharply cut tibial dilator.
The dilator should not be fully inserted until the most superior cortical and subchondral
bone is opened by fully rotating motions.
- Fig: Enlargement of Tibial Socket (in preparation)
- The socket is completed using the 10 mm dilator. Soft tissue debris and sharp edges are
removed from the edge of the socket using a shaver or rasp.
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- Graft-Passage
- Fig: Insertion of Beath Pin (17KB)
The knee-joint is fully flexed to 140°. A 2.4 mm beath pin is inserted via the
anteromedial arthroscopy portal through the femoral socket and out through the lateral
femoral condyle and the skin. With the beath-pin a large suture loop is pulled through the
knee-joint.
- Fig: Pull-Through Suture (in preparation)
With the knee-joint flexed to 100° an arthroscopic grasping clamp is used to pull the
suture form the anteromedial arthroscopy portal out the medial parapatellar incision. Both
ends of the suture are fixed together with a clamp.
- Fig: Pull-Through Suture (in preparation)
With the knee-joint flexed to 100° an arthroscopic grasping clamp is used to pull a
suture loop from the anteromedial arthroscopy portal out the medial parapatellar incision.
The ends are secured by pulling the free ends through the suture loop.
- Fig: Graft-Passage (6KB)
The graft is introduced into the parapatellar incision and pushed carefully into the
tibial socket. Occasionally a hypertrophic medial plica prevents the passage and has
therefore to be removed. Sometimes slight extension of the knee-joint facilitates the
passage of the graft beneath the patella. Under direct endoscopic vision a mallet is
tapped onto the guide wire until the tibial end is fully seated inside the tibial socket.
The guide wire is removed using a vise-grip.
- Fig: Femoral Seating of Graft (16KB)
The holding sutures from the femoral end of the graft are put through the sling of the
pull-through suture. With slight extension of the knee-joint, first the pull-through
suture and subsequently under direct arthroscopic vision the femoral end of the graft are
pulled into the femoral socket.
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- Graft-Fixation
- Fig: Tibial Fixation (10KB)
The knee is flexed to 100° and the first SysorbŪ-screw is inserted from the parapatellar
incision into the tibial socket. The previously created notch prevents the screw from
spinning around the graft. The graft is held tightly with the holding-sutures to prevent
the screw from catching some of the superficial graft-fibers. The tibial screw is screwed
just underneath the joint surface
- Fig: Femoral Fixation (6KB)
80 Newton of tension is applied to the femoral graft and the joint is brought several
times through a full arc of motion. The knee is fully bent and the femoral SysorbŪ-screw
is inserted via the anteromedial arthroscopy portal.
- Fig: The Fully Restored ACL (7KB)
The restored anterior cruciate ligament using tibial and femoral bioabsorbable
interferences screws.