Knee Arthroscopy Approach

What it exposes. Knee arthroscopy gives minimally invasive diagnostic and therapeutic access to every intra-articular compartment of the knee — the suprapatellar pouch, medial and lateral gutters, patellofemoral joint, both tibiofemoral compartments and the intercondylar notch (ACL and PCL). It is among the most frequently performed orthopaedic procedures worldwide. Primary indications:

• Meniscal pathology — tears managed by repair or partial meniscectomy
• ACL and PCL reconstruction
• Cartilage procedures — microfracture, debridement, OATS
• Loose body removal
• Synovectomy for inflammatory arthritis or PVNS
• Lateral release for selected patellofemoral disorders
• Diagnostic arthroscopy when imaging is inconclusive Advantages: small incisions, direct visualisation of intra-articular structures, same-day surgery in most cases, rapid rehabilitation versus open procedures, and the ability to combine diagnosis with treatment in one sitting. Disadvantages: requires specialised equipment and training, fluid extravasation with compartment-syndrome risk, limited access to some structures without accessory portals, and a learning curve for complex procedures. Position & landmarks. Supine on the operating table with the leg hanging free off the side of the table or in a leg holder maintaining 70-90 degrees of flexion. A thigh tourniquet (about 300mmHg after exsanguination) is optional; a lateral post at thigh level allows valgus stress for medial-compartment access. The knee is palpated with the joint at 90 degrees to mark the patella (poles and borders), the patellar tendon (inferior patella to tibial tubercle), the joint line (the soft spot adjacent to the tendon) and the tibial tubercle.

The exposure is the standard two-portal technique: establish the anterolateral (viewing) portal first, then create the anteromedial (working) portal under direct vision, triangulate the instruments, and only then add accessory portals if the pathology demands. There is no true internervous plane — arthroscopy uses small stab incisions through skin and capsule directly into the joint.

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Neurovascular structures at risk, by portal

The infrapatellar branch of the saphenous nerve (IPBSN). The IPBSN emerges from beneath sartorius and runs horizontally across the anterior knee about 3-5mm below the standard portal sites. It is the most commonly injured structure — injury occurs in 10-30 percent of cases and produces anterolateral or anteromedial knee numbness, usually well tolerated. Prevention uses horizontal skin incisions parallel to the nerve, staying at joint-line level, and avoiding overtight sutures. Complications

Compartment syndrome — recognise extravasation early. Fluid extravasation through a capsular defect into the calf or thigh is the mechanism. Risk factors are prolonged surgery, high pump pressures and capsular tears. Watch for increasing leg swelling, pain out of proportion and tense compartments; prevention means monitoring pump pressure (keep less than 60mmHg), periodically palpating the calf and thigh, limiting operative time, and recognising capsular tears. Established compartment syndrome is an orthopaedic emergency treated by immediate four-compartment fasciotomy.

Instrument breakage. Shavers, graspers and other instruments can break intra-articularly; perform an instrument count before and after the case, retrieve broken fragments immediately (a loose metal body damages cartilage), and add portals or convert to a mini-open approach if needed. Extensile options. When the two-portal set-up is insufficient: add far medial/lateral portals for ACL femoral tunnel drilling and better triangulation; use posteromedial and posterolateral portals with transillumination; convert to inside-out or outside-in meniscal-repair techniques; or extend a portal to a mini-open arthrotomy (for example a mini-open posterior-horn meniscal repair). Pump pressure can be raised (up to 60mmHg) for bleeding control, but only with awareness of the extravasation risk.

• ACL reconstruction — patellar tendon (BTB) autograft and ACL reconstruction — hamstring autograft — the principal ligament reconstructions performed through these portals.
• ACL reconstruction technique and revision ACL reconstruction — including the far AM portal for anatomic femoral tunnel drilling.
• PCL reconstruction — requires a posteromedial portal.
• Arthroscopic partial meniscectomy and meniscal repair — all-inside and inside-out.
• MPFL reconstruction — for patellofemoral instability.
• Cartilage procedures (microfracture, debridement, OATS), loose body removal, synovectomy, lateral release, and diagnostic arthroscopy.

Guidelines, registries and global practice. Volumes for degenerative meniscal pathology have fallen substantially since the FIDELITY and METEOR trials. The global consensus across major societies now favours non-operative management first for degenerative tears and meniscal preservation (repair) over resection in younger patients with traumatic, repairable tears.

Practice points with global validity:

• Document that non-operative management (structured physiotherapy, activity modification, weight optimisation) was offered before arthroscopy for any degenerative tear.
• Reserve arthroscopy for true mechanical symptoms (locking blocking full extension), a failed conservative trial, or an acute traumatic tear pattern.
• Counsel that surgery does not slow the natural history of osteoarthritis progression.
• Favour repair over resection in young patients with peripheral, vertical longitudinal tears, especially with concurrent ACL reconstruction.