Lifetime Risk of Total Knee Arthroplasty After ACL Reconstruction and Meniscus Repair
Patients who undergo ACL reconstruction with meniscus repair have a significantly increased lifetime risk of requiring total knee arthroplasty (TKA) compared to the general population, with a cumulative incidence of 1.4% at 15 years post-reconstruction, which is seven times higher than matched controls (0.2%). 1
Risk Factors for Osteoarthritis Development After ACL Reconstruction
- ACL reconstruction with medial meniscectomy increases osteoarthritis odds 3.14 times compared to ACL reconstruction alone (95% CI: 2.20 to 4.48) 2, 3
- ACL reconstruction with partial meniscectomy increases osteoarthritis odds 1.87 times compared to ACL reconstruction alone (95% CI: 1.45 to 2.42) 2, 3
- Cartilage injury at the time of ACL reconstruction increases osteoarthritis odds 2.31 times compared to no or less severe injury (95% CI: 1.35 to 3.94) 2, 3
- Multiple structure injuries (ACL with meniscal injuries) present an even higher risk for osteoarthritis development compared to single structure injuries 4
- Following ACL injury, approximately 20% of patients will develop osteoarthritis regardless of treatment 5
Patient-Specific Risk Factors for TKA After ACL Reconstruction
- Age ≥50 years at time of ACL reconstruction significantly increases TKA risk (hazard ratio: 37.28) 1
- Female sex increases TKA risk (hazard ratio: 1.58) 1
- Higher comorbidity score (≥5 points) increases TKA risk (hazard ratio: 5.91) 1
- Male sex (hazard ratio: 0.63) and age <20 years at ACL reconstruction (hazard ratio: 0.07) are protective factors against requiring future TKA 1
Surgical Factors Affecting TKA Risk
- Low surgeon annual volume of ACL reconstructions (≤12 cases/year) increases subsequent TKA risk (hazard ratio: 2.53) 1
- ACL reconstruction performed in university-affiliated hospitals increases TKA risk (hazard ratio: 1.51) 1
- Concurrent meniscal repair or debridement at time of ACL reconstruction does not appear to increase arthroscopy risk 1
Challenges of TKA After ACL Reconstruction
- TKA following ACL reconstruction has longer operative times compared to primary TKA (88 vs. 73 minutes) 6
- Risk of reoperation after TKA is 5.5 times higher in patients with prior ACL reconstruction 6
- 50% of patients with prior ACL reconstruction require implant removal during TKA 6
- Tibial exposure during TKA can be more difficult after ACL reconstruction, requiring tibial tubercle osteotomy in 14% of cases 7
- Post-operative stiffness requiring manipulation under anesthesia is more common after TKA in patients with prior ACL reconstruction (23% vs. 0% in controls) 7
- Performing TKA within 9 months of any knee arthroscopy increases complication risk 8
Clinical Implications
- Despite the increased risk, the absolute lifetime risk of requiring TKA after ACL reconstruction with meniscus repair remains relatively low at 1.4% after 15 years 1
- The most common complications after TKA in patients with prior ACL reconstruction are instability and stiffness, suggesting difficulties in achieving proper soft tissue balance 5
- Male patients and those with prior ACL reconstruction specifically for ACL injury have higher complication rates after subsequent TKA 8
- Patients should be counseled about the increased lifetime risk of TKA, particularly those with additional risk factors such as older age, female sex, and higher comorbidity scores 1