Healing of acute anterior cruciate ligament rupture on MRI and outcomes following non-surgical management

Key points

1. 01Standard treatment for an acute ACL tear is reconstruction with a tendon graft, which has roughly an 80% success rate but carries downsides such as donor-site morbidity and loss of proprioception.
2. 02This technique stitches the patient's own torn ACL back together, drills microfracture holes at the femoral attachment to release bone marrow cells, and injects platelet-rich plasma (PRP) to biologically stimulate healing.
3. 03In 50 young athletes with partial ACL tears, knee laxity, function scores, and return to sport improved significantly at 5 years.
4. 04Only 4 of 50 patients (8%) had a re-rupture, far below the up-to-90% failure rates seen with older primary-repair methods.
5. 05The approach is reserved for partial tears with strict patient selection, and reconstruction remains available as a fallback if repair fails.

How it was conducted

Design

Prospective case series (single arm, no control group)

Participants

50 young athletes (mean age 28.3 years) with acute partial ACL tears

Tear types

30 partial anteromedial bundle, 8 partial posterolateral bundle, 12 both bundles partial, 0 complete tears

Intervention

Arthroscopic primary suture repair plus femoral footprint microfracture (bone marrow stimulation) and activated PRP injection

Outcomes

KT-2000 side-to-side laxity, IKDC objective score, Tegner/SANE/Marx/Noyes/Lysholm scores, return to sport, second-look arthroscopy

Follow-up

5 years; all patients available at final follow-up

What they found

• Anterior translation difference versus the unaffected side fell from 4.1 mm preoperatively to 1.4 mm at 5-year follow-up (P < .05).
• Final IKDC objective score was normal in 39 patients (78%), nearly normal in 10, and abnormal in 1, giving 98% normal or near-normal.
• 39 patients (78%) fully resumed sport activity.
• 4 patients (8%) had a retear during sport and underwent reconstruction within 2 years of the primary repair.
• Significant improvement was seen in Tegner, SANE, Marx, Noyes, and Lysholm scores at 5 years (P < .05).
• Second-look arthroscopy in 6 patients (12%) revealed a healed ACL that was stable on probing with minimal fibrous tissue.
• No infections or major postoperative complications occurred, and the technique was reported as having a 90% mid-term success rate.

Limitations

• There was no control group, including untreated partial-tear patients, so spontaneous healing cannot be ruled out and the technique cannot be directly compared with reconstruction.
• This is a small single-center, single-arm case series limited to carefully selected young athletes with partial (not complete) tears, which limits generalizability.
• Healing was confirmed by second-look arthroscopy in only 6 of 50 patients, and outcomes depend heavily on strict patient selection and rehabilitation compliance.
• The 11 patients with nearly normal or abnormal IKDC scores all had associated meniscal or chondral lesions, complicating interpretation of the repair's effect.

Why it matters

For patients

If you are a young, active person with a partial (not complete) ACL tear, repairing and biologically healing your own ligament may restore stability and let you return to sport while preserving the natural ligament, though it is not yet proven better than a graft.

For clinicians

For carefully selected partial ACL tears, primary repair with bone marrow stimulation and PRP gave a low 8% re-rupture rate at 5 years and keeps reconstruction available as a fallback, but the absence of a control group means it should be offered cautiously and not yet as a replacement for reconstruction.

For readers

This study reflects a shift toward biological repair of the ACL rather than replacement, but the evidence is early-stage and needs controlled, long-term trials before changing practice.