Endoscopic Bone-Patellar-Tendon-Bone ACL Reconstruction

E. Lyle Cain Jr

Michael K. Ryan

Setup/Equipment

• A 10-mm double-10 blade scalpel facilitates an even tendon cut and prevents tendon splitting.

• A small saggital saw with a 10-mm blade and ¼-in curved osteotomes facilitate optimal graft harvest.

• PEEK interference screws (Arthrex, Naples, FL) are inert, do not cause cysts, do not disintegrate, will not break during insertion, and produce minimal artifact if subsequent MRI is needed.

• A 5.5-mm arthroscopic burr facilitates adequate notchplasty.

• A tibial drill guide (tip-aiming guide set at 53 degrees).

• Acorn reamers (10 mm) optimize femoral tunnel drilling with a transtibial technique and allow variable transtibial placement of the femoral tunnel.

Positioning/Draping

• Placing the patient supine on a flat table allows access to the posteromedial knee if a meniscocapsular junction (ramp lesion) repair is needed.

• High thigh tourniquet.

• The bump is clamped at the end of the table on the operative side (Fig. 40-1A).

• This is positioned just beneath the Achilles tendon, just proximal to the heel so knee is at 60 degrees with the midfoot on the bump and 90 degrees with the toes on the bump (Fig. 40-1B).

• The kidney post is clamped to the ipsilateral side, about four fingerbreadths above the superior pole of the patella to allow valgus stress to be applied.

• The patient is moved close to the post, so that his thigh easily contacts it when placing a valgus force.

Graft Harvest

• The tourniquet is elevated, and a 6-cm midline incision is made from the inferior pole of the patella to the medial aspect of the tubercle.

• The skin and subcutaneous tissue are incised sharply (Fig. 40-2A).

Figure 40-1 | A. Anterior view demonstrating the position of the bump behind the distal calf with the leg fully extended, and the location of the lateral post, which facilitates a valgus force to optimally view the medial compartment. B. Lateral view demonstrating the knee at 90 degrees of flexion with the toes on the bump, the location of the tourniquet proximally on the thigh, and the location for the lateral post.

• Dissection with cautery is carried through adipose tissue to the paratenon; then, subcutaneous flaps are developed medially and laterally to allow arthroscopic portal placement (Fig. 40-2B).

• The paratenon is incised in the midline in line with the skin incision.

• Metzenbaum scissors are used to release the paratenon proximally and distally and separate it from the tendon (Fig. 40-2C).

• The medial and lateral borders of tendon need to be visible for measurement.

Figure 40-2 | Midline approach for graft harvest: (A) midline incision from inferior patellar pole to tibial tubercle; (B) subcutaneous flaps developed medial and lateral to borders of tendon to allow portal placement and smooth instrument insertion; (C) paratenon dissection, medial and lateral flaps created to allow closure over tendon and to prevent soft tissue from blocking portal sites.

• A 10-mm double-blade scalpel is used to incise the middle one-third of the tendon from the inferior pole of the patella down to the tubercle (if tendon width is <30 mm in width, a 9-mm tendon graft is harvested) (Fig. 40-3).

Figure 40-3 | Central third of patellar tendon is incised with a 10-mm-wide double-10 blade. Tendon width of <30 mm requires a 9-mm graft harvest.

• A hemostat clamp is placed behind the graft and pushed down to bone. Measurement is made from the inferior aspect of the hemostat (in cases of Osgood-Schlatter or Sinding-Larsen-Johansson, care should be taken to measure the tendon insertion properly on preoperative radiographs, so as not to inaccurately include the bony ossicle).

• A ruler is used to measure the length of the tibial and patellar plugs.

• The tibial plug (femur) should be about 25 mm.

• The patellar plug (tibia) should be about 20 mm (15 mm in very small patients).

• For tibial plug harvest, a small 10 mm wide saggital saw is used to score the tibial cuts (vertical first) and then cuts are made to full depth at an angle of 70-90 degrees on the medial and lateral sides. The transverse cut is made completely through the anterior cortical bone (Fig. 40-4A).

• A ¼-in curved osteotome is used to free the plug from distal cut (Fig. 40-4B).

• Occasionally, an osteotome may be needed in the medial and lateral cuts if the plug is not freed from the distal cut.

Figure 40-4 | Tibial cut: (A) small 10 mm wide saggital saw used to make vertical cuts through anterior cortex, followed by distal horizontal cut, making sure to connect the corners; (B) a ¼-in curved osteotome frees the plug from its bed easily if cuts were complete.

• Once the bony plug is free, Metzenbaum scissors are used to gently release any soft tissue attachments.

• During cutting of the patellar plug, an assistant holds the graft or the surgeon holds it in his or her noncutting hand, moving it away from the side being cut.

• The patellar plug is cut starting from the distal patellar pole and moving slowly proximally in line with the measured cuts, making sure to keep the blade angled ˜30 degrees out of the sagittal plane in each direction (Fig. 40-5A).

• A 10-mm blade has ˜2-mm excursion; so as long as the corner of the blade remains above the anterior surface of the patella, the cut will not be too deep. Angling the blade 30 degrees from the sagittal plane results in a narrow posterior bone plug to prevent a stress riser and subsequent patellar fracture.

• The proximal cut is scored with the corner of the blade, and then a full cut is made to a depth of 10 mm (avoiding a wide transverse patellar cut to prevent patellar fracture).

• An osteotome is used to release the plug proximally, and from medial and lateral if needed (Fig. 40-5B).

Figure 40-5 | Patellar cut: (A) patellar plug is cut from distal to proximal, not anterior to posterior to better control depth. If tip of blade is just above the anterior cortex, depth is no more than 10 mm; (B) a ¼-in curved osteotome frees the patellar plug; as with the tibial plug, cuts must be complete and corners must meet.

• The tendon is closed with an interrupted no. 0 braided absorbable suture.

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