Does meniscal damage after ACL injury reduce load sharing and accelerate osteoarthritis?

ACL injury commonly coexists with meniscal pathology, and preservation of meniscal function is important because the meniscus is a primary tibiofemoral load-sharing structure. The overall evidence supports the claim, with the strongest findings for altered joint mechanics and for the clinical association between meniscal loss and later osteoarthritis.

Biomechanical evidence

• The meniscus distributes tibiofemoral load, increases the effective contact area between femur and tibia, and attenuates focal cartilage loading.
• In a cadaveric ACL-reconstruction model of medial bucket-handle tears, meniscectomy versus meniscal repair reduced tibiofemoral contact area and increased both mean and peak contact pressures in both joint compartments at every tested flexion angle.
• These findings directly support the mechanism that meniscal loss or dysfunction—including extrusion—concentrates load onto articular cartilage rather than distributing it across the joint surface.

Osteoarthritis implications

• Longitudinal and systematic-review evidence consistently links concomitant meniscal surgery, particularly meniscectomy, with greater later radiographic osteoarthritis after ACL reconstruction.
• A systematic review reported increased radiographic OA at 5–10 years after partial meniscectomy; complete-meniscectomy series reported radiographic OA in nearly all cases.
• Broader review evidence estimates OA risk after meniscectomy at roughly two- to ten-fold higher, and both medial and lateral meniscal surgery have been identified as independent OA risk factors.

Mechanistic imaging findings

• ACL-injured knees show greater progression of medial meniscal extrusion than contralateral knees.
• Greater posterior meniscal extrusion is associated with higher cartilage T1ρ and T2 relaxation values in the posterior medial femoral condyle, MRI markers consistent with cartilage-matrix alteration.
• Together, these observations align mechanical overload with early cartilage degeneration, although elevated contact stress is best regarded as a strongly supported mechanistic contributor rather than an isolated proven cause of clinical OA.

Bottom line

• Meniscal damage, extrusion, or loss after ACL injury substantially impairs load distribution and raises cartilage contact stress; meniscectomy is also strongly associated with accelerated post-traumatic osteoarthritis.