ACL Reconstruction.
Hamstring · patellar tendon · allograft.
ACL reconstruction replaces a torn anterior cruciate ligament with the patient's own tissue — typically hamstring or patellar tendon — using arthroscopic keyhole technique. Graft choice is matched to each patient's age, sport, and clinical priorities.
Procedure overview
Arthroscopic keyhole surgery using small portals. Bone tunnels are drilled through the tibia and femur along the anatomical course of the native ACL. The graft is passed through the tunnels and fixed at both ends — most commonly with an endo-button on the femoral side and an interference screw on the tibial side.
Graft options
Three graft choices, each with trade-offs:
Hamstring
The most common choice in New Zealand. Smaller incision, less anterior knee pain post-operatively. A slightly higher re-injury risk has been reported in young athletes returning to high-pivot sport.
Patellar tendon
A larger graft with bone blocks at both ends. Lower re-injury risk; some patients experience longer-term anterior knee pain or kneeling discomfort. Recovery is slightly longer.
Allograft
Donor tissue. Reserved for revision cases or multiple-ligament reconstruction where additional autograft is unavailable.
Pre-surgery requirements
Pre-operative range of motion is essential — a stiff knee at the time of surgery commonly leads to a stiff knee afterwards. Physiotherapy in the weeks before surgery to regain full extension and minimise swelling is part of the standard pathway.
Phased recovery timeline (0–12+ months)
- Week 0–2 — protection, pain control, swelling reduction, full extension
- Week 2–6 — range of motion, gentle quadriceps activation
- Week 6–12 — strengthening phase, gym-based programme
- Month 3–6 — running progression, change of direction work
- Month 6–9 — sport-specific drills
- Month 9–12 — return to sport readiness testing
- Month 12+ — full return to pivoting sport
Graft healing biology
The graft takes approximately 8 weeks for the bone-tunnel healing phase, then matures over 12–18 months as it remodels into ACL-like tissue. Strength continues to improve throughout the first post-operative year.
Outcomes
Return to sport rates are high in well-rehabilitated patients. The re-rupture rate is approximately 5%; risk is highest in young patients returning to high-pivot sport before 12 months.
Return to driving and work
Driving: 3–4 weeks for right knee with automatic vehicle; longer for manual.
Work: 1–2 weeks office; 6+ weeks manual depending on duties.
Ready to discuss your case?
Bring a GP referral, prior imaging, and any ACC claim information.