Meniscus Tear

**The menisci** are two C-shaped cartilage structures (medial and lateral) sitting between the femur (thighbone) and tibia (shinbone) within the knee joint. They serve crucial functions: - **Shock absorption** — distribute up to 50% of joint load - **Stability** — provide secondary restraint to knee motion - **Lubrication** — help distribute synovial fluid - **Proprioception** — provide sensory feedback about knee position **A meniscus tear** is a partial or complete disruption of this cartilage. Tears are classified by: **By Mechanism:** - **Acute (Traumatic) Tears**: Sudden injury — twisting, cutting, or pivoting on a planted foot; common in sports - **Degenerative Tears**: Gradual wear-and-tear over years; often without specific injury; associated with osteoarthritis **By Pattern (Visualized on MRI):** - **Vertical/Longitudinal**: Common in young athletes; can cause "bucket handle" tears - **Horizontal**: More common in degenerative tears - **Radial**: Run from inner edge outward; often disrupt meniscal function significantly - **Complex**: Combination patterns, common in older patients - **Bucket handle**: Large vertical tear with displaced fragment — can cause locking **By Location (Vascular Supply):** - **Red zone (outer 1/3)**: Has blood supply — can heal; surgical repair attempted - **Red-white zone (middle 1/3)**: Limited blood supply - **White zone (inner 2/3)**: No blood supply — cannot heal; often requires removal **Treatment Implications:** - Tears in the **red zone** of younger patients can often be repaired (preserving the meniscus) - Tears in the **white zone** typically require partial meniscectomy (removal of the torn portion) - **Degenerative tears** often respond as well to physical therapy as to surgery — modern evidence strongly favors conservative trial first

## Root Causes **Acute Traumatic Tears:** - **Twisting injury** — most common mechanism; foot planted, knee rotates - **Hyperflexion** — squatting deeply with rotation - **Direct contact** — blow to the knee in football, hockey - **Combined ACL injury** — meniscus tears in 50-70% of ACL ruptures - Common in: soccer, basketball, football, skiing, tennis, wrestling **Degenerative Tears:** - **Age-related cartilage degeneration** — meniscus becomes less elastic and more brittle - **Cumulative microtrauma** — years of wear and tear - **Knee osteoarthritis** — meniscus degenerates as part of joint deterioration - **Genetic predisposition** — family history of meniscus problems - Often associated with prior knee injury or surgery **Risk Factors:** - **Age >50** for degenerative tears - **Sports requiring cutting/pivoting** for acute tears - **Prior knee surgery** — increases meniscus vulnerability - **Previous meniscus tear** — recurrence risk 5-10% - **Knee misalignment** — varus (bow-legged) or valgus (knock-knee) - **Obesity** — increases knee load - **Occupational kneeling/squatting** (carpet layers, miners, gardeners) - **Female sex** — hormonal effects on cartilage in some studies

## Conservative Treatment (First-Line for Most Tears) **Strongest evidence for**: degenerative tears, small tears, tears in older patients, tears without mechanical symptoms **1. Activity Modification:** - Reduce or temporarily stop activities causing pain - Avoid deep squatting, twisting, and pivoting during acute phase - Cross-train with low-impact activities (swimming, cycling, elliptical) **2. Physical Therapy (Cornerstone of Treatment):** *Acute Phase (Weeks 1-2):* - Pain management — RICE protocol - Pain-free range of motion exercises - Quadriceps activation (straight leg raises, isometrics) - Avoid positions that aggravate symptoms *Strengthening Phase (Weeks 3-8):* - **Quadriceps strengthening** — most important for knee stability - **Hip strengthening** — gluteus medius and maximus (offload the knee) - **Hamstring strengthening** — knee stabilizers - **Calf strengthening** — supports lower limb mechanics - Closed-chain exercises (squats to comfortable depth, leg press) *Functional Phase (Weeks 8-12):* - Sport-specific or activity-specific training - Plyometrics for athletes - Progressive return to activities - Address dynamic movement patterns **3. Pain Management:** - NSAIDs (ibuprofen, naproxen) for 2-4 weeks during flares - Topical NSAIDs for localized application - Acetaminophen as adjunct - Cortisone injection — controversial; provides short-term relief but may accelerate cartilage damage with repeated use **4. Hyaluronic Acid Injection (for Degenerative Cases):** - May provide modest symptom relief - Works better for early arthritis than isolated meniscus tears **5. PRP (Platelet-Rich Plasma):** - Emerging evidence for meniscus tears, particularly with associated arthritis - Not yet considered standard treatment ## Surgical Treatment **Modern Evidence Has Shifted Away from Surgery for Most Degenerative Tears** Multiple landmark studies (FIDELITY trial, METEOR study, Sihvonen et al) have shown that arthroscopic surgery for degenerative meniscus tears provides NO BENEFIT over physical therapy. Conservative treatment is now first-line for degenerative tears. **Surgery is Still Indicated For:** **Acute Traumatic Tears:** - Locked knee that cannot be reduced - Bucket handle tears with mechanical symptoms - Failed 3-6 months of conservative treatment in younger active patients - Tears in young athletes wishing rapid return to sport **Procedures:** - **Arthroscopic Partial Meniscectomy**: Removes torn portion; quick recovery (2-4 weeks); but increases long-term arthritis risk by 30-50% - **Meniscus Repair**: Suturing the torn pieces; preferred when possible (red zone tears in younger patients); longer recovery (4-6 months); preserves meniscus tissue - **Meniscus Transplant**: Donor meniscus for patients with severe cartilage loss; specialized procedure - **Meniscus Root Repair**: For root tears (where meniscus attaches to bone); critical to repair as untreated root tears progress to severe arthritis **Outcomes:** - Partial meniscectomy: 80-90% short-term satisfaction, but 30-50% develop arthritis within 10-15 years - Meniscus repair: 70-90% healing rate; better long-term joint preservation - Recovery: meniscectomy 2-4 weeks; repair 4-6 months for full activity