Sports Medicine
ACL Reconstruction
Arthroscopic ACL reconstruction using the graft best suited to your anatomy, activity level, and goals — with a milestones-based return-to-sport program.
Overview
Why the ACL doesn’t heal on its own
The anterior cruciate ligament is one of the primary stabilizers of the knee, running diagonally through the joint and controlling rotational movement. Unlike many other soft tissues in the body, the ACL has a very poor capacity for self-repair. It sits inside the joint surrounded by synovial fluid, which interferes with the normal clotting and healing cascade. A torn ACL will not grow back together on its own — reconstruction is required to restore stability and protect the other structures of the knee. Learn more from Dr. Hacker who performs ACL reconstruction in San Diego.
Without treatment, repeated episodes of giving way can damage the menisci and articular cartilage, accelerating the development of arthritis. Reconstruction replaces the torn ligament with a graft — a tendon harvested from your own body or from a donor — that is secured into bone tunnels and serves as a scaffold for a new ligament to grow.
Causes & Risk Factors
How ACL tears happen
ACL tears most commonly occur during twisting, pivoting, sudden deceleration, or hyperextension of the knee. Approximately 70% are non-contact injuries — meaning no collision occurred. Landing awkwardly from a jump, cutting sharply in soccer or basketball, or planting and pivoting in football are classic mechanisms.
Women are 5 to 6 times more likely than men to sustain an ACL injury, even when playing the same sport at the same level of intensity. Differences in anatomy (wider pelvis, increased Q angle), hormonal influences on ligament laxity, and neuromuscular patterns during landing all contribute to this elevated risk.
Symptoms
- A loud pop at the time of injury, often felt and heard
- Immediate swelling — the knee fills with blood (hemarthrosis) within hours
- Giving way or buckling with pivoting or lateral movement
- Loss of full range of motion
- Inability to return to play or activity that same day
Diagnosis
Confirming the diagnosis
The Lachman test and pivot-shift test are the two most sensitive physical examination findings for an ACL tear. In the Lachman test, the tibia is pulled forward on the femur with the knee partially bent — a positive test feels like a soft, undefined endpoint rather than a firm stop. The pivot-shift test assesses rotational instability and is strongly correlated with functional impairment.
MRI is obtained to confirm the ACL tear, assess for associated meniscus or cartilage injuries (which occur in 50–70% of ACL tears), and evaluate the other ligaments. X-rays rule out associated fractures, including the subtle Segond fracture that is pathognomonic for ACL disruption.
Associated injuries to evaluate
- Medial or lateral meniscus tear
- Medial collateral ligament (MCL) sprain
- Articular cartilage damage
- Bone bruising (bone contusion on MRI)
- Posterolateral corner injury
The Procedure
Arthroscopic reconstruction
ACL reconstruction is performed arthroscopically as an outpatient procedure — you go home the same day. The surgery typically takes 60 to 90 minutes. Through two small portals, a camera and instruments are inserted into the knee joint. The torn ACL remnant is removed, the joint is inspected, and any associated meniscus or cartilage injuries are addressed at the same setting.
The graft is then prepared and passed through two precisely placed bone tunnels — one in the tibia and one in the femur — that reproduce the anatomic origin and insertion of the native ACL. The graft is secured with fixation devices and will incorporate into the bone tunnels over the following months.
Graft options
- Bone-patellar tendon-bone (BPTB): the gold standard for competitive athletes; excellent stiffness and bone-to-bone healing. Harder to get the ‘perfect spot’ for placement
- Hamstring autograft: lower donor-site morbidity than BPTB; strong and reliable in most patients
- Quadriceps tendon: a newer option
- Allograft (donor tissue): no donor-site harvest or extra post operative pain; suitable for many patients; longer biologic integration timeline, technically better positioning.
Graft selection is individualized and discussed thoroughly at your preoperative consultation based on your age, sport, prior injuries, and anatomy.
Recovery
A milestones-based rehabilitation program
ACL rehabilitation is not driven by a calendar — it is driven by achieving specific functional benchmarks before progressing to the next phase. This philosophy reduces re-tear risk and ensures your neuromuscular system has truly adapted before increasing demand.
Weeks 0–2
Swelling and pain control. Elevation, ice, compression. Quad sets and straight-leg raises begin immediately. Walking with crutches as tolerated.
Weeks 2–12
Progressive weight-bearing. Restore full range of motion. Begin closed-chain quad and hamstring strengthening. Stationary bike introduced.
Months 3–6
Running and straight-line jogging when quad strength reaches 70% of the opposite leg. Sport-specific agility and plyometric drills introduced progressively.
Months 6–12
Return to full sport when strength symmetry exceeds 90% and functional testing is passed. Most competitive athletes return at 9–12 months.
Potential complications
ACL reconstruction is a safe and well-established procedure. Complications are uncommon but include: superficial numbness near the incision site (particularly with patellar tendon graft), surgical site infection, deep vein thrombosis, graft failure or re-tear (most common in young athletes returning to pivoting sports), and post-operative stiffness (arthrofibrosis). A careful, progressive rehabilitation program significantly reduces these risks.
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