ACL-Restoration: (SemiT): List of figures

ACL-Restoration with Semitendinosus Tendon

Commented Step-by-step Illustrations

Main text: Operative Technique | Back to the title page

Back to the main text

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.

Back to the main text

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 (Kaltec®, 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

Back to the main text

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 (Syntofil®).
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.

Back to the main text

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.

Back to the main text

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.

Back to the main text

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 Sysorb® 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.

Back to the main text

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.

Back to the main text

Graft-Fixation

Fig: Tibial Fixation (10KB)
The knee is flexed to 100° and the first Sysorb®-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 Sysorb®-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.