What is the treatment plan for a central root attachment tear of the posterior horn medial meniscus with moderate medial subluxation of the meniscal body from the medial femoral tibial compartment of the knee?

Management of Medial Meniscus Posterior Root Tear with Meniscal Subluxation

Arthroscopic surgical repair using a pullout technique should be performed for this central root attachment tear of the posterior horn medial meniscus, as non-operative management leads to poor outcomes with 87% failure rates, progressive arthritis, and high conversion to arthroplasty at 5-year follow-up. 1

Why Surgery is Indicated for Root Tears

Root Tears Are Biomechanically Distinct from Degenerative Tears

• Posterior root tears of the medial meniscus disrupt the circumferential hoop stress mechanism, making them biomechanically equivalent to total meniscectomy. 2
• Root avulsions cause significant medial meniscal extrusion (3.28 mm versus 1.60 mm in intact menisci) and gap formation between the root attachment site and meniscal body. 3
• This biomechanical failure leads to deleterious alteration of medial compartment loading profiles with decreased contact area and increased mean contact pressure at all flexion angles beyond 0°. 2

Natural History Without Repair is Poor

• Non-operative treatment of medial meniscus posterior root tears results in 87% overall failure rate at 5-year follow-up. 1
• 31% of patients progress to total knee arthroplasty at mean 30 months after diagnosis. 1
• Mean Kellgren-Lawrence grades progress significantly over time (1.5 to 2.4), with arthritis rates increasing from 51% to 78%. 1
• Female patients have particularly poor outcomes with lower IKDC scores (49 versus 75 in males) and higher arthroplasty rates. 1

Surgical Technique: Arthroscopic Pullout Repair

Recommended Approach

• The pullout repair technique reattaches the torn meniscus to the tibial plateau immediately medial or anteromedial to the posterior cruciate ligament using sutures passed through a trans-tibial tunnel. 4, 5
• Two 2-0 PDS sutures (or No. 2 Ethibond sutures) are placed through the meniscus root: one through the red-red zone 3-5 mm medial to the torn edge, and another through the meniscocapsular junction 3-5 mm medial to the torn edge. 4, 5
• A 5-mm diameter tibial tunnel is created from the anteromedial proximal tibia to the prepared tibial plateau site. 5
• Sutures are pulled through the tunnel and fixed distally using either an EndoButton along the anterolateral tibial cortex or a 3.5-mm cortical screw with washer. 4, 5

Biomechanical Restoration

• Surgical repair restores meniscal displacement to near-intact levels (1.46 mm versus 1.60 mm in native knees), compared to 3.28 mm in avulsed state. 3
• Repair significantly reduces gap formation at the defect site under both unloaded and loaded conditions. 3
• In situ pullout repair restores contact area and mean contact pressure to levels statistically indistinguishable from the intact meniscus. 2
• This restoration of joint mechanics helps halt progression of cartilage degeneration and osteoarthritis. 4

Key Differences from Degenerative Meniscal Tears

Why Standard Guidelines Don't Apply

• Root tears are traumatic injuries that disrupt meniscal function completely, unlike degenerative tears where conservative management is first-line. 6, 7
• The AAOS guidelines recommending conservative management for degenerative tears specifically exclude patients with mechanical derangement and do not address root tears. 8
• Root tears cause true mechanical dysfunction through loss of hoop stress, not just degenerative symptoms. 2

Common Pitfalls to Avoid

• Do not treat this as a standard degenerative meniscal tear—root tears require different management due to their unique biomechanical consequences. 1, 2
• Delaying surgical intervention allows progressive cartilage damage and arthritis development that may become irreversible. 1, 4
• Non-operative management should not be offered as first-line treatment given the 87% failure rate and poor natural history. 1
• Partial meniscectomy is inappropriate as it does not restore the root attachment or hoop stress mechanism. 2

Expected Recovery

• Recovery from arthroscopic root repair typically requires 2-6 weeks. 6
• At least 1-2 weeks off work is necessary, with longer periods for physically demanding occupations. 6
• Post-operative rehabilitation should include early mobilization and structured physical therapy focusing on quadriceps and hamstring strengthening. 6