What treatment options are available for a patient experiencing pain and instability on the left medial meniscus, particularly when going down stairs?

Treatment of Medial Meniscus Pain and Instability

Start with conservative management consisting of structured physical therapy focused on quadriceps and hamstring strengthening, combined with activity modification and NSAIDs for pain control, while immediately evaluating for concurrent ACL injury before considering any surgical intervention. 1, 2

Initial Diagnostic Priority: Rule Out ACL Deficiency

Before addressing the meniscus, you must evaluate for ACL injury because:

• Meniscal tears are typically a consequence rather than the primary cause of knee instability 2
• Studies show 6% of patients develop anterior instability and 22% develop medial instability after isolated meniscal procedures when ligamentous injury is missed 3
• MRI has 96% sensitivity and 97% specificity for detecting both meniscal tears and concurrent ligamentous injuries 2
• If ACL deficiency exists, address the ligamentous instability first or concurrently, as ACL-deficient knees have significantly elevated risk of subsequent meniscal damage due to altered biomechanics 2

Conservative Management Protocol (First-Line Treatment)

The BMJ guidelines strongly recommend against arthroscopic surgery for degenerative meniscal tears, showing no benefit over exercise therapy 1. This applies to your situation unless there is a locked knee or true mechanical obstruction.

Specific Conservative Interventions:

• Structured physical therapy with semimembranosus tendon stretching and passive range of motion exercises twice weekly for 8 weeks reduces medial meniscal extrusion by an average of 0.6 mm in non-weight-bearing and 0.5 mm in weight-bearing positions 4
• Quadriceps and hamstring strengthening to restore dynamic knee stability 2
• NSAIDs and cryotherapy (ice through wet towel for 10-minute periods) for pain and swelling control 2
• Activity modification to reduce repetitive loading and stress, particularly avoiding stairs initially 5
• Weight-bearing as tolerated, but modify activities that provoke pain 2

Expected Outcomes with Conservative Treatment:

Research demonstrates significant improvements after 8 weeks of physical therapy: knee pain reduction from 7.0 to 1.1 on numerical rating scale, and knee extension ROM improvement from -12.3° to -3.1° 4. The mechanism appears to be restoration of medial collateral ligament tension, which reduces meniscal extrusion 4.

When Surgery May Be Appropriate

Arthroscopic intervention is only appropriate for:

• Bucket-handle tears causing true mechanical locking (persistent objective locked knee, not just clicking or catching) 1, 6
• Peripheral, well-vascularized tears in younger patients where repair is feasible 6
• Failure of 8-12 weeks of structured conservative management in patients with persistent functional limitations 1

Critical Surgical Considerations:

• Meniscal repair is strongly preferred over partial meniscectomy to avoid premature osteoarthritis 6
• If instability persists after partial meniscectomy, consider that the procedure itself may have unmasked or contributed to ligamentous instability (occurs in 6-22% of cases) 3
• For rare cases of meniscal dislocation with instability interfering with daily activities, operative stabilization by reconstruction of meniscotibial ligaments may be curative 7

Common Pitfalls to Avoid

• Do not proceed with isolated meniscal surgery without evaluating ACL integrity - this is the most critical error, as unaddressed ACL deficiency leads to continued instability and further meniscal damage 2, 3
• Do not rush to arthroscopy for mechanical symptoms alone (clicking, catching) - these are not indications for surgery unless there is persistent objective locking 1
• Avoid complete immobilization - early mobilization reduces pain and prevents muscular atrophy 2
• Do not use compression bandaging - insufficient evidence supports its use for knee injuries, unlike ankle sprains 1

Return to Activity Timeline

If conservative management succeeds:

• Return to sedentary work: 1-2 weeks 2
• Return to physical labor/sports: minimum 6 weeks 2
• Stair descent pain typically improves within 4-8 weeks with appropriate physical therapy 4