Proximal ACL Tears and Non-Surgical Improvement
Proximal ACL tears can spontaneously heal without surgery in select cases, with one study demonstrating complete healing and return to athletic activity in 14 patients with proximal third tears, though this represents a small subset and two patients experienced rerupture at 2.5 years. 1
Evidence for Spontaneous Healing
Documented Healing Rates
A retrospective study of 14 patients with complete proximal ACL ruptures (8 in proximal third, 6 midligament) showed spontaneous healing without specific rehabilitation or bracing, with all patients returning to their former activity level at mean 30-month follow-up. 1
At final follow-up, mean Lysholm-Gillquist score was 97, with 10 knees rated normal and 4 nearly normal by IKDC criteria. 1
MRI confirmation showed end-to-end continuous ACL with homogeneous signal in all healed cases. 1
Critical caveat: Two patients (14%) experienced ACL rerupture 2.5 years after initial injury, indicating that spontaneous healing may not provide the same long-term stability as surgical reconstruction. 1
Location-Specific Healing Potential
Proximal third tears demonstrated healing capacity in this cohort, though the mechanism and predictability remain unclear. 1
The average age was 31 years (range 23-41), suggesting this may be more relevant for adult recreational athletes rather than younger competitive athletes. 1
Long-Term Outcomes: Surgery vs. Non-Surgical Management
Osteoarthritis Risk
The most important finding from a quality-of-life and morbidity perspective is that there is very low certainty evidence showing no difference in osteoarthritis odds between ACL reconstruction and rehabilitation alone over 5-37 year follow-up. 2
This challenges the traditional assumption that surgery prevents long-term degenerative changes. 2
Both surgical and non-surgical approaches carry similar osteoarthritis risk, suggesting the decision should be based on functional needs rather than presumed joint preservation. 2
Functional Outcomes Without Surgery
Non-surgical management with rehabilitation can yield successful results in less active patients with sedentary occupations. 3
Activity modification without reconstruction is considered appropriate for older patients with ACL injuries, as activity levels generally decrease with age and ACL deficiency becomes better tolerated. 4
Clinical Decision Framework
Candidates for Non-Surgical Management
The American Academy of Orthopaedic Surgeons recommends non-surgical management as first-line treatment for older patients (>55 years), considering reduced risk and consequences of subsequent meniscal tears with age. 4
Patients with lower activity demands and sedentary occupations are appropriate candidates. 3
Those willing to accept activity modification and avoid jumping, cutting, or pivoting sports. 3
Candidates Requiring Surgery
Active patients wanting to resume jumping, cutting, or pivoting sports, those with physically demanding occupations, or patients who fail non-surgical management should undergo ACL reconstruction. 3
When surgery is indicated for acute isolated ACL tears, early reconstruction (within 3 months) is strongly recommended because risk of additional cartilage and meniscal injury increases after this timeframe. 2
This represents a strong recommendation from the American Academy of Orthopaedic Surgeons. 2
Common Pitfalls
Overestimating the frequency of spontaneous healing: While the study by Costa-Paz et al. showed healing in 14 patients, this represents a highly selected population where surgery was postponed for various reasons, not a generalizable healing rate. 1
Assuming surgery prevents osteoarthritis: The evidence shows no difference in long-term osteoarthritis development between surgical and non-surgical management. 2
Delaying surgery beyond 3 months in surgical candidates: This increases risk of secondary meniscal and cartilage damage. 2
Failing to recognize that spontaneous healing, even when it occurs, may not provide equivalent long-term stability: The 14% rerupture rate at 2.5 years in the healing cohort is concerning. 1
Practical Recommendation
For most patients with proximal ACL tears, the decision should not be based on expectation of spontaneous healing, but rather on functional demands and activity goals. While spontaneous healing can occur, it is unpredictable and may not provide durable stability. 1 The choice between surgery and rehabilitation should prioritize the patient's activity level, with surgery reserved for those requiring high-demand activities and rehabilitation appropriate for lower-demand patients, recognizing that long-term osteoarthritis risk is similar regardless of treatment choice. 2, 3