Tibia Posterolateral Approach

What it exposes. The posterolateral approach gives direct access to the posterolateral tibial plateau, the posterior tibial cortex, and — via the Frosch modification — the lateral articular surface for direct visualisation and posterior buttress plating. It is the workhorse exposure for displaced posterolateral corner fragments of the tibial plateau. Why this approach (and not anterolateral). The tibial plateau has an inherent 7 to 10 degree posterior slope, and posterolateral fragments displace posteriorly under axial load combined with valgus stress. The posterolateral corner is the least supported region, and a fragment here simply cannot be buttressed from an anterolateral approach. Only a true posterolateral exposure places the plate on the posterior surface to resist that posterior displacement; malreduction leads to posterior subluxation and early post-traumatic arthritis. Indications. - Posterolateral tibial plateau fractures (isolated posterolateral column)

• Schatzker II fractures with a significant posterolateral split-depression component
• Bicondylar fractures (Schatzker V/VI) requiring posterolateral column fixation
• Revision surgery for posterolateral fragment malunion
• Access to the posterior tibial cortex for bone grafting (diaphyseal variant) Contraindications. - Medical unfitness for prone positioning (spinal cord injury, recent myocardial infarction)
• Active infection of the skin over the approach
• Severe posterior soft tissue compromise (delay surgery until recovery)
• Isolated anterior or medial fractures (use the appropriate alternative approach) Alternative approaches. - Anterolateral approach — for lateral plateau split/depression without a posterolateral fragment
• Posteromedial approach — for posteromedial fragments (saphenous nerve at risk, sensory only; generally considered safer)
• Extended lateral with fibular osteotomy — when combined anterolateral and posterolateral access is needed in one incision
• Anteromedial approach — for medial plateau fractures Position and landmarks. The patient is placed prone on a radiolucent table with chest rolls or a Wilson frame, all pressure points padded (face, chest, pelvis, patellae, ankles), arms abducted less than 90 degrees, and the C-arm verified to access from the lateral aspect. The affected knee is slightly flexed over a bolster — this relaxes the common peroneal nerve and reduces traction risk. A high-thigh tourniquet is used if planned (tourniquet-free surgery is also reasonable). Palpable landmarks are the fibular head, the biceps femoris tendon (inserting on the fibular head), Gerdy's tubercle (anterolateral tibial insertion of the iliotibial band), the lateral joint line, and the common peroneal nerve rolling over the fibular neck. The incision is longitudinal, behind the fibular head and anterior to the biceps tendon proximally, curving distally along the lateral fibular border for 8 to 12cm depending on the exposure required.

Work from skin down to the posterolateral tibial plateau along the fibular border, protecting the common peroneal nerve at every layer, then develop the peroneus-longus / soleus interval to apply a posterior buttress plate. The Frosch technique — a single incision combining a lateral arthrotomy with the posterolateral exposure, without fibular osteotomy — is the current standard.

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Structures at risk, by layer

CPN injury management. If the nerve is found transected intra-operatively, perform a primary repair. For a suspected neurapraxia, observe and document, then arrange urgent EMG / nerve conduction studies at 3 weeks (after Wallerian degeneration if the injury is axonal). For a post-operative foot drop with no clinical or EMG recovery by 3 months, consider nerve exploration; an established permanent foot drop is managed with an ankle-foot orthosis and, if refractory, tendon transfer (tibialis posterior to the dorsum).

Extensile options. - Fibular osteotomy — when the standard approach gives inadequate exposure of a large or complex posterolateral fragment: an oblique osteotomy of the fibular neck (posterolateral to anteromedial), performed only after the CPN is identified and protected, repaired at the end with a small plate or tension band. It adds morbidity — fibular nonunion in about 5 percent and higher CPN risk.

• Proximal extension — along the biceps femoris toward the posterolateral femoral condyle; the CPN becomes more superficial proximally, increasing risk.
• Distal extension — along the fibula to reach the tibial diaphysis for fractures extending into the shaft, staying in the same intermuscular plane.
• Combined approaches — for bicondylar Schatzker V/VI fractures: posterolateral for the PL fragment plus posteromedial (PM fragment) and/or anterolateral (lateral column), planned around positioning (see below). Complications

Outcomes by fracture pattern. Good outcomes track anatomic articular reduction. Isolated posterolateral split fractures achieve good or excellent results in roughly 85 to 90 percent with 15 to 20 percent OA at 10 years; posterolateral split-depression 75 to 85 percent with 25 to 30 percent OA; and bicondylar (Schatzker V/VI) 60 to 75 percent with 40 to 50 percent OA. Of CPN injuries, about 60 percent recover fully, 30 percent partially, and 10 percent are permanent. Closure summary. Irrigate, achieve haemostasis, drain (away from the CPN) if preferred, close capsule and fascia with absorbable suture, approximate subcutaneous tissue and close skin. Rehabilitate with non-weight-bearing or touch weight-bearing for 6 to 12 weeks, early ROM aiming for 0 to 90 degrees by 6 weeks, and DVT prophylaxis until mobile.

• Posterolateral tibial plateau fracture ORIF (isolated posterolateral column) — the principal operation, with posterior buttress plating.
• Schatzker II lateral split-depression with a significant posterolateral component.
• Bicondylar Schatzker V/VI — posterior column fixation (combined with posteromedial and/or anterolateral approaches in prone or floating position).
• Revision ORIF for posterolateral fragment malunion.
• Posterolateral tibial diaphyseal exposure and posterior tibial cortex bone grafting (distal/shaft variant).
• The fibular-osteotomy modification for complex or large fragments needing wider exposure.

Guidelines, Registries & Global Practice Tibial plateau fractures are managed at trauma centres worldwide, and the principles are convergent across examination systems. CT-based assessment of every operatively considered plateau fracture and the three-column concept (Luo) are now near-universal in defining the posterior columns and selecting the approach. Side-by-side principles (where guidance converges): | Body | Position on plateau fractures |

|------|------------------------------| | AO Foundation | CT mandatory for articular fractures; posterior fragments need dedicated posterior / posterolateral approaches and buttress fixation; staged management with spanning external fixation for high-energy injuries with soft-tissue compromise | | BOA / BOAST (open and soft tissue) | Early soft-tissue assessment, photographic documentation, joint orthoplastic care for open injuries; definitive fixation only once soft tissues permit | | OTA / AAOS | Anatomic articular reduction and restoration of the mechanical axis as primary goals; CT-based planning is standard of care | Registry / population evidence: - Population-based incidence is approximately 10 per 100,000 per year, with a bimodal distribution (high-energy in younger men, fragility pattern in women older than 50).

• Long-term ORIF cohorts show post-traumatic arthritis in roughly 30 percent at long follow-up, strongly driven by residual malalignment greater than 5 degrees rather than age. Global practice variation. In high-resource settings, dedicated posterolateral plates, fragment-specific implants and routine CT are standard. In resource-limited settings, the same biomechanical principle (posterior buttress) is achieved with contoured one-third tubular or small-fragment T/L plates, and external fixation has a larger role for temporisation and occasionally definitive treatment. Consent (globally applicable): discuss common peroneal nerve injury (approximately 3 to 5 percent in this approach, mostly transient), infection (2 to 5 percent, higher with soft-tissue compromise), post-traumatic arthritis (long-term roughly 20 to 40 percent), stiffness, and the possibility of future total knee arthroplasty if articular damage is severe.