When does an ACL tear need surgery?
Not every ACL tear requires reconstruction. Older, less active patients with isolated ACL injuries and stable knees can sometimes manage without surgery. However, for patients who want to return to pivoting sports, who have concomitant meniscus or cartilage injuries, or who experience recurrent giving way in daily activities, ACL reconstruction is generally recommended.
The decision is made on the basis of MRI findings, clinical examination (Lachman test, pivot-shift), your activity goals, and the presence of other injuries. I discuss this in detail at the first consultation.
Graft choice
ACL reconstruction requires a tendon graft to replace the torn ligament. The three main autograft (your own tissue) options are hamstring tendon (HT), bone-patellar tendon-bone (BPTB), and quadriceps tendon (QT). All three are well-studied, and quadriceps tendon can be harvested either as an all-soft-tissue graft or with a small bone plug taken from the upper pole of the patella.
What the evidence shows: A systematic review and meta-analysis (Mouarbes et al., Am J Sports Med, 2019) comparing all three graft types found no significant differences in knee stability, functional scores, or graft failure rates between HT, BPTB, and QT. However, QT autograft showed significantly less harvest-site pain than BPTB, and slightly better functional scores compared to HT. A more recent meta-analysis of randomised trials (White et al., Knee Surg Sports Traumatol Arthrosc, 2026) reached the same overall conclusion — graft failure, laxity, and patient-reported outcomes are comparable across all three grafts, with QT tending toward lower donor-site morbidity. All three remain appropriate choices; graft selection should be individualised based on anatomy, activity level, and surgeon experience.
My standard graft for primary ACL reconstruction is quadriceps tendon autograft harvested with a bone plug, fixed as a single-bundle reconstruction. I favour this combination for a specific set of reasons, set out below — but hamstring tendon and BPTB remain entirely reasonable choices, and I use them when a patient's anatomy or history points that way.
Why quadriceps tendon with a bone plug, for most of my patients
- The bone plug allows bone-to-bone healing at the femoral tunnel, which generally incorporates faster and more predictably than soft-tissue-to-bone healing
- Quadriceps tendon provides a larger cross-sectional area and more consistent graft diameter than hamstring tendon, which can be thin or hypoplastic in some patients — this matters for graft strength and reduces the need to fall back on allograft augmentation
- Donor-site morbidity (anterior knee pain, sensory change) is generally lower than with BPTB harvest, and hamstring strength is preserved for patients who need it for pivoting or kicking sports
- It leaves hamstring tendon available as a graft option later, which is useful if revision surgery is ever needed
What the evidence shows: A 2025 systematic review and meta-analysis of over 7,700 patients (Malinowski et al., EFORT Open Rev) comparing quadriceps tendon harvested with a bone plug versus all-soft-tissue quadriceps tendon found comparable functional outcomes and knee laxity between the two, with some evidence of a lower revision rate in the bone-plug group — though the authors noted the certainty of evidence for that specific finding was limited and called for more randomised comparisons. Bone-plug harvest carries its own small, specific risk (patellar fracture has been reported in case series, generally in well under 1% of patients) that all-soft-tissue harvest avoids, which is a genuine trade-off worth discussing rather than a one-sided argument.
Single-bundle vs. double-bundle ("two-tunnel") technique
The native ACL has two functional bundles — anteromedial (AM) and posterolateral (PL) — that tension differently through the range of knee motion. Single-bundle reconstruction restores the ligament as one tunnel in the femur and one in the tibia, positioned within the combined AM-PL footprint. Double-bundle reconstruction uses two separate femoral and two separate tibial tunnels (sometimes described by patients as the "2-route" technique) to reconstruct each bundle individually, aiming to more closely reproduce the ACL's native rotational control.
Double-bundle technique generated a lot of interest in the 2000s and early 2010s on the theory that restoring two bundles should control rotational (pivot-shift) laxity better than one. In practice, the accumulated randomised trial evidence has not shown a clear advantage.
What the evidence shows: A 2024 systematic review and meta-analysis of 13 randomised controlled trials (Xu et al., Arthroscopy) comparing anatomic double-bundle with single-bundle reconstruction found no significant differences in subjective scores (IKDC, Lysholm, Tegner), objective laxity (side-to-side difference, pivot-shift, Lachman), or radiographic osteoarthritis at a minimum of 12 months, when both techniques were performed to a high standard of anatomic tunnel placement. The single-bundle group in this analysis had a higher overall complication rate, though the authors cautioned that complication reporting was inconsistent across the included trials and this finding should be interpreted with some caution rather than as a settled conclusion.
In my own practice I use single-bundle reconstruction for the large majority of primary ACL cases. With correct anatomic tunnel placement, the outcome evidence does not support routinely adding the technical complexity, longer operative time, and additional tunnels of a double-bundle approach — and a simpler single-bundle construct is generally easier to revise later if that ever becomes necessary. Double-bundle technique is a reasonable option in some surgeons' hands and in specific anatomical situations, but it is not something I default to.
The surgery
ACL reconstruction is performed arthroscopically — through small incisions using a camera and instruments. The torn ligament is removed and a tunnel is drilled in both the femur and tibia to position the new graft in the anatomical ACL footprint. The graft is fixed with screws or buttons — with a bone-plug quadriceps tendon graft, the bone plug itself is typically secured in the femoral tunnel with a small interference screw.
The procedure is performed under general or spinal anaesthesia. Meniscus tears, if present, are addressed at the same time.
Recovery milestones
- Week 1–2: Partial weight-bearing, swelling control
- Week 4–6: Full weight-bearing, stationary bike
- Month 3: Light jogging, gym work
- Month 6: Sport-specific training
- Month 9–12: Return to competitive sport (depending on graft maturation)
PCL reconstruction
Posterior cruciate ligament (PCL) tears are less common than ACL tears and are often managed non-operatively in isolation. Surgical reconstruction is recommended for grade III PCL injuries, multi-ligament injuries, or persistent instability after conservative treatment. The principles are similar to ACL reconstruction — arthroscopic, graft-based, anatomical footprint restoration.
For complex instability involving the outer structures of the knee alongside a cruciate tear, see the article on posterolateral corner (PLC) reconstruction. For concurrent meniscus injuries, see meniscus surgery.
Driving, Work & Follow-Up
Typical logistics (individual recovery varies — we'll set your specific timeline together)
- Driving: Often 2–4 weeks for an automatic transmission (longer if your surgery is on your right leg or you drive manual).
- Desk / remote work: Often within 1–2 weeks.
- Physical or manual work: Physical work or a return to pivoting sport follows the strength and rehabilitation milestones described above — typically several months, not weeks.
- Follow-up visits: Around 2 weeks, 6 weeks, 3 months, 6 months, and 1 year, including strength and return-to-sport testing before clearance.
Frequently Asked Questions
Can I travel to Japan or coordinate this from abroad?
Yes. I regularly coordinate care for international and expatriate patients. Initial questions and your imaging can often be reviewed remotely, with the consultation and surgery itself scheduled around a visit to Tokyo. I'll help you plan the timing, and follow-up afterward can be managed with a mix of in-person visits and remote communication with you or your local physician.
References (PubMed)
Mouarbes D, et al. Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis of Outcomes for Quadriceps Tendon Autograft Versus Bone-Patellar Tendon-Bone and Hamstring-Tendon Autografts. Am J Sports Med. 2019;47(14):3531–3540. DOI: 10.1177/0363546518825340
White T, Castro M, Antonio L, Hing W, Tudor F, et al. Quadriceps, hamstring and patella tendon autografts for primary anterior cruciate ligament reconstruction demonstrate similar clinical outcomes, including graft failure, joint laxity and complications: a systematic review with meta-analysis of randomised controlled trials. Knee Surg Sports Traumatol Arthrosc. 2026;34:1631–1646. DOI: 10.1002/ksa.12755
Malinowski K, Kim DW, Surma J, Macius Z, Tollefson L, LaPrade RF, Pękala P, Mostowy M. Quadriceps tendon-bone vs all soft-tissue autografts for primary anterior cruciate ligament reconstruction: a systematic review and meta-analysis of 7,748 patients. EFORT Open Rev. 2025;10(12):865–881. DOI: 10.1530/EOR-2024-0204
Xu Y, Ma T, Li Z, et al. Anatomic Double-Bundle and Single-Bundle Reconstructions Yield Similar Outcomes Following Anterior Cruciate Ligament Rupture: A Systematic Review and Meta-analysis. Arthroscopy. 2024;40(2):481–494. DOI: 10.1016/j.arthro.2023.05.017