Does an ACL rupture always need surgery?

Does an ACL rupture always need surgery?

Anterior cruciate ligament (ACL) rupture has long been managed on a default pathway toward early reconstruction for young, active patients. Australia, in particular, has some of the highest ACL reconstruction rates globally, and despite there being an ongoing growing body of evidence into why the bodies and sports played in Australia lead to this heightened risk, there is renewed scrutiny of who really needs surgery, and when. 

A growing body of evidence, spanning Australian cohorts and international randomized trials, suggests that non-operative pathways and modern repair techniques deserve a seat at the table alongside reconstruction. The question is not “surgery or nothing,” but “which first-line strategy best fits this patient, at this time, given their goals and tear characteristics?” Reviewing recent data with a focus on the Australian Cross-Bracing Protocol (CBP) and contemporary ACL repair trials brings to light a new angle of approach.

The Cross-Bracing Protocol

The CBP was pioneered in Australia by Dr Merv Cross and Dr Tom Cross. It treats acute ACL rupture by immobilising the knee at 90° flexion for four weeks, then gradually unlocking range of motion to 12 weeks, alongside supervised rehabilitation. The rationale is orthopaedic first principles: reduction and immobilisation to approximate torn ACL ends and provide a mechanical milieu for healing. In the initial prospective cohort (n=80) managed within 4 weeks of injury, MRI at ~3 months showed evidence of ACL continuity in 90% (50% “continuous and thickened”; 40% “continuous but thinned/elongated”). Greater MRI healing was associated with better 12-month patient-reported outcomes, lower knee laxity, and higher return to pre-injury sport; re-injury occurred in 14%. These results don’t prove superiority over surgery just yet, but they demonstrate biological healing is possible and clinically meaningful in many patients. A head-to-head randomised trial (EMBRACE) is now recruiting in Australia to compare CBP with early reconstruction. 

Two points are crucial for clinicians considering CBP. First, timing matters: the protocol is designed for acute ruptures commenced as early as feasible (ideally within 10 days, up to 4 weeks), reflecting a potential “healing window.” Second, the program is structured, supervised, and not benign, patients are anticoagulated for DVT prophylaxis during bracing and undergo carefully staged rehab. For appropriately selected patients who can adhere to the protocol, the early Australian experience suggests CBP can convert a proportion of ACL ruptures into a healing trajectory without immediate surgery. 

Is there evidence for “spontaneous” healing and non-operative rehab?

CBP sits within a broader shift in how we think about ACL biology. The KANON randomised trial (rehabilitation with optional delayed reconstruction vs. early reconstruction) has been re-analysed with modern MRI criteria: about one-third of patients randomised to initial rehab demonstrated ACL healing on MRI by two years, and healing correlated with better symptoms and quality of life at both 2 and 5 years. This does not mean everyone heals spontaneously (far from it) but it challenges the dogma that the ACL “cannot heal,” and reinforces that structured rehab with selective, delayed surgery can yield outcomes comparable to early reconstruction for many. Meta-analysis likewise suggests similar patient-reported outcomes between primary rehab with optional surgery and early surgery, with a possible trend toward less radiographic osteoarthritis, though certainty remains low.

Historical failures to contemporary outcomes

ACL repair was largely abandoned in the 1980s due to high failure rates. Newer techniques including suture repair with internal bracing, dynamic intraligamentary stabilisation (DIS), and biologically augmented methods such as bridge-enhanced ACL restoration (BEAR), aim to address prior biomechanical and biological limitations.

BEAR has the strongest randomised data to date. In a young, active US cohort treated within 45 days of injury, BEAR was non-inferior to autograft reconstruction at two years for IKDC symptoms and instrumented laxity, with superior hamstring strength; re-injury rates were numerically higher in BEAR but not statistically different (14% vs 6%). The technique has since received broader regulatory clearance for midsubstance/proximal tears, and ongoing studies are tracking longer-term durability and osteoarthritis risk. 

Across techniques, a 2024 meta-analysis of randomised and cohort studies (n=549) found no significant differences between repair and reconstruction in failure rate, anteroposterior laxity, or PROMs, though repair had higher rates of hardware removal, driven in part by DIS implants. These pooled results suggest that, in carefully selected acute tears (especially proximal), repair can be an acceptable alternative to reconstruction in the right hands. Heterogeneity is substantial, and indications, surgeon experience, and implant choices matter. 

Internal brace augmentation of reconstruction (reinforcing a graft with suture-tape) is also attracting interest. Early randomised and comparative studies indicate similar short-term function and laxity vs. standard reconstruction, with possible early strength or confidence benefits; however, robust longer-term clinical advantages (and any trade-offs) remain to be proven. 

Practical implications for Australians

Not every ACL tear needs surgery straight away, anymore. Patients with ongoing knee instability, high pivoting demands, or associated injuries such as meniscal tears usually still benefit from early reconstruction. But for motivated patients with fresh tears and good tissue quality, trying the Cross-Bracing Protocol or structured rehabilitation first can be a safe, evidence-based option – provided they’re closely followed and surgery remains on the table if instability continues.

Modern ACL repair techniques, including BEAR and suture-anchor repair with internal bracing, work best when used early for proximal or midsubstance tears with healthy tissue. These repairs can achieve short-term results similar to reconstruction, though long-term outcomes and osteoarthritis risk are still being studied. In Australia, where reconstruction rates are among the highest in the world, especially in young athletes, validated non-operative pathways could help reduce unnecessary surgeries and their costs. The key is ensuring clinicians have the experience, infrastructure, and follow-up systems to deliver high-quality bracing and rehabilitation safely when non-operative options are explored.

Regardless of treatment, rehabilitation remains the most important determinant of outcome. ACL management is no longer one-size-fits-all, and the Cross-Bracing Protocol offers a promising non-surgical route for some. This modern repair provides a middle ground, and reconstruction remains essential for others. The art lies in matching the right patient to the right pathway, supported by high-quality rehabilitation and evolving evidence.

Filbay SR, Dowsett M, Chaker Jomaa M, et al. Healing of acute anterior cruciate ligament rupture on MRI and outcomes following non-surgical management with the Cross Bracing Protocol. Br J Sports Med. 2023;57(23):1490-1497. doi:10.1136/bjsports-2023-106931

Frobell, Richard B., et al. “A randomized trial of treatment for acute anterior cruciate ligament tears.” New England Journal of Medicine 363.4 (2010): 331-342.