Question 1

Which graft is best - hamstring, patellar tendon, or allograft?

Accepted Answer

NO SINGLE BEST GRAFT - all have pros and cons. HAMSTRING (most common in Australia, 60-70%): Less anterior knee pain, smaller scars, faster early recovery. Disadvantages: hamstring weakness, slightly higher failure rate in some studies (6-9% vs 3-5%). PATELLAR TENDON (gold standard, 30-40% in Australia): Bone-to-bone healing, lowest failure rate (3-5%), no hamstring weakness. Disadvantages: anterior knee pain (10-30%), kneecap problems, larger scar. ALLOGRAFT (uncommon in Australia, less than 10%): No harvest site pain, shorter surgery. Disadvantages: highest failure rate (10-15%), slower incorporation (12-18 months), disease transmission risk (very low). QUADRICEPS TENDON (emerging, 5-10%): Strong graft, less anterior knee pain than patellar, no hamstring weakness. Disadvantages: less long-term data, not all surgeons experienced. RECOMMENDATION: Young high-demand athletes (under 25, pivoting sports) - patellar tendon or quadriceps (lower failure rate). Recreational athletes (over 30) - hamstring (less donor site pain, adequate outcomes). Revision ACL - allograft or quadriceps (spares previously harvested tissue). DISCUSS WITH SURGEON - choice based on age, activity level, sport, surgeon expertise, patient preference regarding potential complications.

Question 2

When can I return to sport after ACL reconstruction?

Accepted Answer

MINIMUM 9 MONTHS, IDEALLY 12 MONTHS for pivoting/contact sports (soccer, basketball, netball, AFL, rugby, skiing). Returning earlier than 9 months DOUBLES re-tear risk. GRADUATED TIMELINE: 3 months - swimming, cycling. 4-6 months - jogging, light running. 6-9 months - agility drills, sport-specific training, non-contact practice. 9-12 months - return to full competition (clearance requires passing ALL return to sport criteria below). RETURN TO SPORT CRITERIA (must pass ALL): (1) TIME - minimum 9 months post-surgery (12 months preferred by many surgeons). (2) STRENGTH - isokinetic testing showing 90% or greater strength of operated leg compared to uninjured leg (quadriceps and hamstring). (3) HOP TESTING - single leg hop for distance, triple hop, crossover hop all within 90% of uninjured leg. (4) FUNCTIONAL MOVEMENT - single leg squat, landing mechanics assessed by physiotherapist (no knee valgus, good control). (5) PSYCHOLOGICAL READINESS - ACL-Return to Sport after Injury (ACL-RSI) scale score greater than 56 (measures confidence, emotions about returning). (6) SURGEON AND PHYSIOTHERAPIST CLEARANCE. REALITY CHECK: Even with successful surgery, only 65-80% of athletes return to pre-injury sport level. Reasons for not returning: fear of re-injury, changed life priorities, moved to different sport, persistent symptoms, psychological barriers. RE-TEAR RISK: 6-9% overall graft failure rate. Higher risk: age under 20 (15-25%), return less than 9 months (up to 20%), same-leg injury. Also 10-15% risk of injuring OTHER knee (new ACL tear in opposite knee).

Question 3

What is the difference between single bundle and double bundle ACL reconstruction?

Accepted Answer

SINGLE BUNDLE (standard technique, 95% of ACL reconstructions): Uses ONE graft to reconstruct ACL. Graft positioned to recreate anteromedial bundle (main functional component of ACL). Single femoral tunnel, single tibial tunnel. Simpler technique, well-established outcomes. DOUBLE BUNDLE (specialized technique, less than 5% of reconstructions): Uses TWO grafts to separately reconstruct both bundles of native ACL (anteromedial and posterolateral bundles). Two femoral tunnels, two tibial tunnels. Goal is more anatomic reconstruction of native ACL structure. THEORETICAL ADVANTAGES OF DOUBLE BUNDLE: Better rotational stability, more anatomic restoration, potentially better long-term outcomes. REALITY - EVIDENCE SHOWS: Multiple high-quality studies and meta-analyses show NO SIGNIFICANT DIFFERENCE in clinical outcomes, re-tear rates, return to sport, or patient satisfaction between single and double bundle at 2-10 year follow-up. DISADVANTAGES OF DOUBLE BUNDLE: (1) Longer, more complex surgery. (2) Requires more graft tissue (need to harvest more hamstring or use two separate grafts). (3) Higher cost (more tunnels, more implants). (4) Not all surgeons trained in technique. (5) Technically difficult in smaller knees. CURRENT CONSENSUS: Single bundle ACL reconstruction remains GOLD STANDARD. Double bundle largely abandoned by most surgeons (was popular 2005-2015 but fell out of favor when studies showed no benefit). ANATOMIC SINGLE BUNDLE: Modern approach focuses on anatomic tunnel positioning (placing tunnels at native ACL footprints) rather than adding second bundle - provides rotational stability benefits without complexity of double bundle. AUSTRALIAN PRACTICE: Greater than 95% of ACL reconstructions in Australia are single bundle anatomic technique. Double bundle only performed by small number of specialized surgeons in research/academic centers.

Question 4

Why does ACL reconstruction take 9-12 months to return to sport when other knee surgeries are faster?

Accepted Answer

ACL GRAFT REMODELING takes 9-12 months (sometimes longer) - this is BIOLOGICAL HEALING process that cannot be rushed. GRAFT REMODELING PHASES: (1) NECROSIS phase (0-4 weeks): Graft cells die after harvest (blood supply lost). Graft weakest during this phase. (2) REVASCULARIZATION (4-12 weeks): New blood vessels grow into graft from surrounding bone and synovium. Graft still weak, prone to failure if overstressed. (3) CELLULAR REPOPULATION (3-6 months): Fibroblasts migrate into graft, start producing new collagen. Graft gradually regains strength. (4) REMODELING (6-18 months): Collagen fibers reorganize along lines of mechanical stress. Graft strength continues to improve. Graft reaches 80-90% of native ACL strength by 12 months (some studies suggest full maturation takes 18-24 months). GRAFT IS WEAKEST at 6-12 weeks (revascularization phase) - this is why early protected weight-bearing and gradual loading critical. RETURN TO SPORT TOO EARLY (less than 9 months): Graft not fully remodeled, increased re-tear risk. Studies show returning less than 9 months doubles graft failure rate (up to 20% vs 10% for those who wait 9+ months). NEUROMUSCULAR RECOVERY also takes 9-12 months: Muscle wasting after surgery (quadriceps inhibition - brain doesn't activate muscle properly post-op). Proprioception deficits (balance, joint position sense). Landing mechanics need retraining. These neuromuscular factors independent of graft strength but equally important for safe return. PSYCHOLOGICAL RECOVERY: Fear of re-injury, confidence rebuilding, trust in knee all take time (often underestimated but critical for performance). CONTRAST WITH OTHER SURGERIES: Meniscectomy (simple removal of torn meniscus) - 4-6 weeks return because no graft remodeling needed. Meniscal repair - 4-6 months (need healing but shorter than ACL). Cartilage procedures - 6-12 months (similar biological constraints). BOTTOM LINE: 9-12 month ACL timeline is BIOLOGICAL REALITY, not arbitrary. Graft needs time to incorporate, remodel, and regain strength. No shortcuts.

Medical Disclaimer

ACL Reconstruction Surgery

📖What is ACL Reconstruction Surgery?

🔬What Causes It?

⚠️Risk Factors

You may be at higher risk if:

🛡️Prevention