Overview
Campbell's preferred treatment for pathologic ACL laxity in an active, healthy patient who wants to stay active is arthroscopic reconstruction with bone–patellar tendon–bone (BPTB) autograft. Surgery is outpatient in almost all patients. Physical therapy is used first to regain muscle tone and motion, usually over 10 to 21 days before surgery. (Campbell)
Successful reconstruction depends on secure anatomic graft placement and physiologic treatment of all secondary stabilizers, including the menisci. (Campbell)
Indications
Pathologic ACL laxity in an active patient who wishes to remain active. (Campbell)
Graft choice. The most commonly used autografts are central one-third patellar tendon, quadrupled hamstrings of 8 mm or more, and quadriceps tendon. Each has enough strength and stiffness to replace the ligament. (Campbell)
Patellar tendon: lower retear rate in young athletes. Harvest risks patellar tendinitis and, if the graft is cut too deep, acute or delayed patellar stress fracture.
Hamstrings: harvest of both tendons weakens knee flexion by about 20%, and saphenous nerve injury can be detrimental. Graft creep may be more frequent than with patellar or quadriceps tendon.
Autograft should routinely be used in young athletes. MOON data in 14- to 22-year-olds showed 2.1 times more failure with hamstring than with patellar tendon autograft.
Allografts are not recommended in younger patients but may be considered in older or lower-demand patients. Their failure rate in athletes and young patients is two to five times that of autograft.
Factors that raise failure risk. Preoperative pivot shift, or hyperextension of more than 5 degrees. Abnormal varus alignment or tibial slope. Adding an anterolateral ligament reconstruction or lateral extraarticular tenodesis lowers failure to under 3%, 2.5 times lower than isolated BPTB reconstruction. (Campbell)
Double-bundle ACL reconstruction has not shown a clinically significant functional benefit. (Campbell)
Technique 56.16: Anatomic Single-Bundle Endoscopic ACL Reconstruction with BPTB Graft (Campbell)
Setup
Place the patient supine. After general endotracheal anesthesia, examine the uninjured knee for reference laxity, then the injured knee for Lachman and pivot shift.
Apply a thigh tourniquet and a well-padded lateral post. Tape a 5-L saline bag to the table as a stop to hold 90 degrees of knee flexion.
Prepare and drape with standard arthroscopy drapes, exsanguinate with an Esmarch wrap, and inflate the tourniquet to 100 mm Hg above systolic pressure.
If preoperative examination showed obvious laxity, proceed to patellar tendon harvest. If the status of the ACL is in question, or more than 90 minutes of tourniquet time is anticipated, make arthroscopy portals and do the joint evaluation and notch debridement before inflating the tourniquet and harvesting.
Infiltrate portals with lidocaine and epinephrine. An arthroscopy pump maintains distention and limits bone bleeding.
Unless contraindicated, give antibiotics and ketorolac before tourniquet inflation (30 mg IV under age 65, 15 mg if over 65 or under 50 kg).
Graft harvest
With the knee at 90 degrees, make a 4- to 6-cm medial parapatellar incision from below the patella to medial to the tibial tuberosity.
Expose the patella and tendon by subcutaneous dissection. Incise the peritenon in the midline and raise flaps medially and laterally.
With the knee flexed, measure tendon width. Harvest a graft 10 mm wide or one third of the tendon, whichever is smaller, from the central portion, starting at the inferior patellar tip. Keep the incisions straight and in single fiber planes. Size is individualized: 11 mm or double-bundle for a large lineman, 8–9 mm for a small patient.
Make the bone cuts with an oscillating saw with a 1-cm blade, run about 15 degrees oblique to a line perpendicular to the anterior patellar cortex, with 2 mm of blade visible. The patellar plug is about 10 mm wide × 20 mm long and 8 mm deep.
Make 22-mm cuts distally and free the tibial plug with a curved osteotome. Flip the plug back into the harvest site. Drill a 2-mm hole 3 mm from its distal tip and pass a No. 5 suture, which an assistant holds to keep the graft clean.
Complete the patellar cut at the inferior pole, 7–8 mm deep and parallel to the anterior cortex.
Graft preparation
Secure the graft on the back table (a graft preparation board makes tensioning easier).
Contour the plugs so that the whole graft passes through a 10-mm sizing trial. Bullet the end of the bone plug.
Drill two holes in each plug (the tibial plug should be 20 mm).
Pass a No. 5 nonabsorbable suture through the better bone plug, which goes into the femoral tunnel, and an 18-gauge wire through the other plug, which goes into the tibial tunnel. The wire prevents cutout before firm fixation.
Mark the bone–tendon junction on the cancellous side at both ends with methylene blue, measure the total graft length, wrap in a saline-soaked sponge and set aside.
Raise an inverted-L flap of tibial periosteum, starting about 2.5 cm below the joint line and extending distally 1 cm medial to the tuberosity. Reflect it medially to expose the proximal tibia.
Arthroscopic evaluation and notch preparation
Make standard anteromedial and anterolateral portals without injuring the remaining patellar tendon.
Examine the knee systematically and treat associated pathology. Suture meniscal repairs before securing the ACL graft.
With the scope in the anterolateral portal and a 5.5-mm full-radius resector in the anteromedial portal, release the ligamentum mucosum and partially resect the fat pad.
Remove soft tissue from the notch and tibial stump by sliding the resector between the ACL stump and the PCL, with the blade opening always facing superiorly or laterally to protect the PCL.
Leave the tibial and femoral footprint outlines intact as references. Identify the lateral intercondylar ridge and lateral bifurcate ridge. Mark the posterosuperior footprint with an awl so the tunnel will have a 2-mm posterior wall and sit about 5 mm from articular cartilage.
With the knee at 30 degrees, assess space between the PCL and lateral wall. Do a limited notchplasty with a 5.5-mm burr, opening the notch to an inverted U. Often only 2–3 mm superiorly and laterally is needed. Do not extend too far medially or superiorly, which would interfere with the patellofemoral joint. Make the notch wide enough posteriorly for the 10-mm reamer, and smooth the edges.
Tibial tunnel
Place the tibial guide with the intended tunnel length and direction in mind. The starting point is about 1 cm proximal to the pes anserinus and 1.5 cm medial to the tibial tuberosity, forming a 30- to 40-degree angle with the tibial shaft. If the femoral tunnel will be drilled transtibially, the tunnel angle is about 45 degrees in the sagittal plane, starting just lateral to the medial collateral ligament. More acute angles undercut the articular surface.
Intraarticular reference points: the ACL stump, the inner edge of the anterior horn of the lateral meniscus, the medial tibial spine and the PCL. In the AP plane the wire should exit just anterior to a line extended from the inner edge of the lateral meniscus, about 7 mm anterior to the PCL and 2–3 mm anterior to the peak of the medial spine.
A guide set at 55–60 degrees to the plateau gives enough tunnel length. The tunnel must contain at least 20 mm of bone. If the tendinous portion is 50 mm or less, increase the guide angle for a tunnel of 45–50 mm.
Advance the wire about 10 mm into the knee and clamp it. Ream first with a reamer 2 mm smaller than the final size. Check the tunnel for impingement through a full range of motion, adjust with the 8-mm reamer, then ream to graft size.
Leave a 2-mm posterior wall between the tibial tunnel and the PCL, and aim the tunnel just lateral to the PCL so the graft lies on it without bowstringing.
Contour the edges with the full-radius resector and rasp.
Femoral tunnel
View from a high anteromedial portal just medial to the patellar tip.
Locate a low medial portal with a spinal needle, about 2.5 cm medial to the patellar tendon and just above the meniscus.
Place the guide so the tunnel is just anterior to the anteromedial bundle, leaving a 2-mm posterior wall and about 4–5 mm from the articular surface.
Flex the knee to about 120 degrees and use a flat-blade reamer to avoid cartilage damage. Advance 1 mm and recheck position, then ream a 30-mm tunnel if possible. Do not enlarge the tunnel or blow out the posterior wall.
Smooth the edges and use a notcher to make a 25-mm slot over the guidewire.
Graft passage and fixation
Pass a suture loop through the femoral tunnel and out through the lateral thigh with an eyelet guidewire. Use it to pull the graft up through the tibial tunnel and into the femoral tunnel. The cancellous surface of the femoral plug faces anteriorly.
Make sure at least 2 cm of bone plug stays in the tibial tunnel. If necessary, recess the graft into the femoral tunnel and use a longer interference screw.
Place a flexible guidewire through the medial portal parallel to the graft and fix with an interference screw, passed through a sheath in a straight line with the tunnel. The screw should engage bone and sit flush with the aperture.
Cycle the knee while holding tension distally. If the graft tightens by more than 2 mm in flexion, remove it and move the femoral tunnel, or both, slightly posterior with a rasp. Slight tightening in extension is normal.
Rotate the tibial plug (counterclockwise in a right knee) so the cancellous side faces laterally, matching ACL fiber orientation.
If there is no pistoning or impingement, hold tension for about 3 minutes while cycling the knee for stress relaxation. Tension the graft with 8 to 10 lb of pull. Overtensioning can cause joint capture or graft necrosis.
Fix the tibial side with a screw equal to the gap size plus 5 mm with the knee in full extension. If the plug lies completely outside the tibial tunnel (for example with an allograft mismatch), use a biocomposite or noncutting screw 1 mm smaller than the tunnel for soft-tissue fixation.
Take the knee through full range of motion and check the graft with a probe: it should be slightly tighter than a normal ACL, with no impingement and no protruding bone or screw.
Check Lachman and pivot shift. The knee should be just slightly tighter than the uninjured side.
Remove the 18-gauge wire and tension sutures.
Closure
Loosely approximate the patellar tendon with simple absorbable sutures through its anterior fibers.
Pack bone from the plug contouring into the patellar defect and close the peritenon.
Remove the thigh and tibial plug sutures, trim protruding bone distally and close the periosteal flap over the tunnel.
Close the subcutaneous layer with interrupted 2-0 absorbable sutures and the skin with a running subcuticular 4-0 suture. Apply loose adhesive strips, a sterile dressing, a cooling sleeve and an elastic wrap.
Two-incision variant (Technique 56.17)
Useful for revision, posterior wall blowout, graft–tunnel mismatch with a long patellar tendon graft, and pediatric patients. It adds a 4-cm lateral incision over the iliotibial band, splitting the band and elevating the vastus lateralis to expose the over-the-top spot. (Campbell)
Postoperative Care
Campbell's rehabilitation protocol (Box 56.12), summarized:
0–2 weeks. Patellar mobilization, quadriceps sets and straight-leg raises, passive extension (full extension emphasized), flexion to 90 degrees, edema control, partial weight bearing 50%–75% on crutches (or without crutches if the brace is locked in extension), brace locked in extension for sleep. Goals: full extension, 90 degrees of flexion, good quadriceps contraction, normal gait.
2–4 weeks. Brace opened for full ROM, flexion progressed to 120 degrees by 4 weeks, stationary bike, full weight bearing and weaning from crutches when gait is normal, early closed-chain work.
4–6 weeks. Full ROM by 6 weeks, progressive closed-chain strengthening, hamstring and quadriceps isokinetic work.
8–10 weeks onward. Slow running progressions, lunges, then sport-specific work. Plyometrics from 16–20 weeks. (Campbell)
Graft incorporation: bone plugs heal in the tunnel at about 6 weeks, and soft-tissue grafts take 2 to 3 weeks longer. (Campbell)
Complications
Donor-site morbidity. Patellar tendinitis (especially with larger grafts) and patellar stress fracture if the graft is cut too deep. (Campbell)
Graft and tunnel problems. Nonanatomic placement, impingement, graft–tunnel mismatch, screw divergence, fixation slippage and excessive graft stress from malalignment. Graft creep and overtensioning also contribute. (Campbell)
Arthrofibrosis and CRPS. Early surgery before motion and muscle tone return is associated with arthrofibrosis, as is combined meniscal repair. Complex regional pain syndrome may be reduced by better patient selection, shorter operating time and early therapy. (Campbell)
Infection. Treat with early arthroscopic irrigation and debridement. About 85% of grafts can be salvaged. (Campbell)
DVT. Consider prophylaxis in high-risk patients and when weight bearing is limited. (Campbell)
Retear. The main outcome concern in young, high-demand athletes. Use autograft and consider addressing anterolateral laxity. (Campbell)
References
Bernholt DL, Mihalko MJ. Arthroscopy of the lower extremity. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 56, Techniques 56.16–56.17, Box 56.12.