Arthroscopic Partial Meniscectomy

Indication. A symptomatic meniscal tear that is not amenable to repair, producing genuine mechanical symptoms (locking, catching, giving way — true mechanical, not pain alone), that has failed conservative management (about 3 to 6 months of physiotherapy, activity modification and NSAIDs). The exception is a bucket-handle tear with a truly locked knee, which is reduced urgently. The objective is to remove only the unstable, torn tissue and leave the maximum amount of stable, contoured meniscus behind. Repair versus resection is the one decision that drives everything. It rests on the tear zone, the pattern, the patient and the joint:

Consent specifically for: acceleration of osteoarthritis (proportional to tissue removed, especially in the young), incomplete pain relief or persistent symptoms, iatrogenic chondral or nerve injury, infection, haemarthrosis, stiffness and loss of extension, and DVT/PE. Setup. Supine with a leg holder allowing 0 to 120 degrees of flexion; a lateral post at mid-thigh to apply valgus stress (medial compartment) and varus stress (lateral compartment). Tourniquet optional and often omitted — a bloodless field is not essential, and the tourniquet adds post-operative pain and may impair assessment of meniscal vascularity. Prophylactic antibiotics (single dose cefazolin 2g or per local protocol). Confirm full passive range of motion before draping — an inability to extend suggests a locked tear.

The goal: establish safe viewing and working portals, perform a systematic diagnostic arthroscopy, classify the tear, then resect only the unstable tissue to a smooth, stable, contoured rim while protecting the articular cartilage, the saphenous nerve, the popliteus tendon and the MCL. The exposure — precise portal placement — is the foundation of the whole operation.

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Rehabilitation | Phase | Timing | Weight-bearing / immobilisation | Rehabilitation | |-------|--------|--------------------------------|----------------| | 1 | 0 to 2 weeks | WBAT immediately; crutches for comfort 1 to 3 days; no brace | Full extension day 1 (critical); quad sets, straight leg raises, ankle pumps; ice and elevation | | 2 | 2 to 4 weeks | Wean crutches by day 7 to 10 | Full ROM by week 2; stationary cycling; closed-chain mini-squats and step-ups; quad strength toward 70 to 80 percent of contralateral | | 3 | 4 to 6 weeks | Full | Progressive resistance (leg press, hamstring curls); running programme; agility; sport-specific drills | | Return to sport | 4 to 6 weeks | — | Full painless ROM; no effusion with activity; quad strength at least 90 percent; functional hop tests greater than 90 percent; sport-specific drills pain-free | Full extension is non-negotiable from day one — any loss beyond 5 degrees signals arthrofibrosis risk and needs aggressive extension work (prone hangs, extension splinting). Long-term, advise activity modification (reduce high-impact loading), weight management (every 1kg increases medial compartment load by 2 to 4kg), quadriceps maintenance, and annual OA surveillance in younger patients; consider a high tibial osteotomy if symptomatic OA develops with malalignment.

Epidemiology & natural history. Meniscal tears are among the most common knee injuries, with an incidence rising with age as degenerative tears accumulate; about a third of adults over 50 have a meniscal tear on MRI, often asymptomatic. Meniscectomy is an established independent risk factor for radiographic knee OA — the classic Fairbank changes (joint-space narrowing, marginal ridging, condylar flattening) — and the relationship is dose-dependent: more tissue resected means higher contact stress and greater OA risk, because even the inner avascular meniscus contributes to hoop-stress load transmission. A systematic review (Petty and Lubowitz, 8 to 16 year follow-up) found radiographic OA significantly more common in operated knees than the contralateral control, but clinical symptoms were not consistently observed and did not correlate with radiographic change. Long-term cohorts show progressive radiographic OA in roughly 40 to 50 percent by 15 to 20 years, more with larger resections and malalignment. Degenerative tears are best understood as a marker of early OA rather than an isolated injury. Functional anatomy. The menisci transmit 50 to 70 percent of knee load in extension and 85 percent at 90 degrees of flexion; loss of meniscal function increases tibiofemoral contact stress two to threefold. They are secondary stabilisers resisting anteroposterior translation (the posterior horn of the medial meniscus is critical in the ACL-deficient knee) and carry mechanoreceptors for proprioception. The blood supply comes from the superior and inferior genicular arteries via a perimeniscal capillary plexus, penetrating the outer 10 to 30 percent (the red-red zone); vascularity is more extensive in children and significantly reduced over age 50.

Portal anatomy.

Key evidence and global guidance. For the degenerative middle-aged knee, high-level evidence has shifted practice decisively toward exercise therapy first-line. The METEOR trial (Katz, NEJM 2013) randomised 351 patients aged 45 and older with a meniscal tear and mild-to-moderate OA to arthroscopic partial meniscectomy plus PT versus PT alone, and found no significant difference in WOMAC physical function at 6 and 12 months (30 percent of the PT group crossed over). The Kise RCT (BMJ 2016) randomised 140 middle-aged patients (mean age 49.5, 96 percent without definite radiographic OA) to supervised exercise versus meniscectomy and found no clinically relevant difference in KOOS4 at 2 years, with superior thigh-muscle strength in the exercise group. The ESSKA meniscus consensus (Beaufils, 2016/2017) concluded arthroscopic partial meniscectomy should not be first-line for degenerative lesions.

Where guidance genuinely differs. For a traumatic tear in a young patient with mechanical symptoms, every society supports early arthroscopic intervention (repair preferred over resection). The divergence is narrow and concerns the degenerative middle-aged knee, where the RCT evidence (METEOR, Kise) supports exercise therapy first-line. True mechanical locking with a displaced unstable fragment remains a surgical indication, while established OA (Kellgren-Lawrence grade 3 to 4) is not helped by arthroscopy and may be worsened. Outcomes and prognostic factors. Short-term results are good — 80 to 90 percent good or excellent at 2 years, 85 to 90 percent return to sport — but deteriorate as OA develops. By 10 to 20 years, roughly 40 to 50 percent have radiographic OA (KL grade 2 or more), 20 to 40 percent symptomatic OA, and 10 to 20 percent have converted to TKA. Outcomes are favourable with minimal resection, neutral alignment, a traumatic tear in a younger patient, no chondral damage and maintained quadriceps strength, and unfavourable with extensive resection (greater than 50 percent), varus or valgus malalignment, a degenerative pattern, concomitant grade 3 to 4 chondral injury, age greater than 50, or BMI greater than 30.