Tibial Tubercle Osteotomy for Extensile Knee Exposure

What it exposes. The tibial tubercle osteotomy (TTO) is an extensile exposure that gives wide access to the whole knee joint - from the tibial plateau to the suprapatellar pouch - in a knee that otherwise cannot be delivered. It works by releasing the extensor mechanism distally: the patellar tendon, patella and quadriceps remain in continuity with the osteotomised tubercle fragment, so the entire mechanism can be lifted proximally and subluxed laterally. Crucially, the quadriceps tendon itself is not divided, so - unlike the V-Y turndown - quadriceps continuity and extensor power are largely preserved. Primary indications. The unifying indication is a stiff, scarred or ankylosed knee in which forcing eversion would avulse the patellar tendon or fracture the patella. - Revision total knee arthroplasty - the classic indication: stiff revision knees, multiple prior operations, infected revisions requiring wide access, or stiff capsular scarring that prevents patellar eversion

• Arthrofibrosis after TKA - open lysis of adhesions and manipulation requiring full joint visualisation
• Complex primary TKA - the ankylosed or severely stiff knee, severe fixed valgus with a tight extensor mechanism, post-traumatic arthritis with scarring, or a knee with a prior tibial osteotomy
• Patella infera (baja) - where the low-riding patella cannot be delivered into the field, the osteotomy transposes the extensor mechanism proximally; the TTO is the only release that addresses a low patella
• Septic TKA - two-stage exchange where wide access is needed for radical debridement and component removal
• Selected supracondylar or intra-articular distal femoral fractures around a TKA where standard fixation access is blocked Contraindications. - Poor skin over the tibial tubercle - multiple anterior scars, thin atrophic skin, or a previous wound that jeopardises healing over the osteotomy (the tubercle is subcutaneous and the fragment is prominent after refixation)
• Severe osteopenia or a highly comminuted proximal tibia - the fragment may be too fragile to hold screws and rigid refixation becomes impossible
• A previous tibial tubercle osteotomy or proximal tibial osteotomy with altered bony anatomy and compromised vascularity
• Active infection with sinus tracking across the tubercle (relative - choose another exposure)
• High anaesthetic or medical risk for a longer, more blood-stained revision procedure Alternative extensile exposures and how to choose. Most surgeons escalate from least to most morbid. A quadriceps snip is attempted first; if the extensor mechanism still will not deliver, a tibial tubercle osteotomy is the usual next step because it preserves quadriceps continuity and gives excellent exposure. The V-Y turndown is reserved for the worst ankylosed knees because of its real cost in extensor power.

The quadriceps tendon, patella, patellar tendon and tibial tubercle form a continuous extensor chain. The TTO detaches the distal end of this chain (the tubercle) so the whole chain can be mobilised proximally and everted laterally. Because the quadriceps tendon is never cut, the mechanism retains its length and the patient is far less likely to suffer an extensor lag than after a V-Y turndown. The single most important anatomical concept is the vascularity of the fragment. The proximal tibia has a dual extraosseous blood supply: a medial and a lateral contribution. The flat osteotomy strips the medial side but deliberately leaves the lateral soft-tissue hinge intact - the tibialis anterior muscle origin and the lateral periosteum. The fragment is therefore vascularised from lateral to medial through this hinge. This is why the fragment is everted laterally (not medially) and why the lateral hinge must be protected: it is the blood supply on which union depends.

Structures at risk, by layer.

Extensile options. Proximally, the osteotomy connects seamlessly with the medial parapatellar arthrotomy; if still more proximal release is needed, a quadriceps snip can be added, but the TTO alone usually suffices. Distally, the osteotomy can be lengthened along the tibial crest for more proximal-tibial exposure when required. Protecting the osteotomy - rehabilitation and union monitoring. Rigid screw fixation is what makes it possible to balance the two competing goals of protecting the osteotomy so the fragment unites and regaining movement in a knee that was stiff in the first place. - A knee brace locked in extension is used for comfort during mobilisation and sleep; most protocols unlock it early for controlled range-of-motion because the rigid fixation is designed to tolerate it.

• Touch-down or partial weight-bearing for the first 6 weeks, progressing to full weight-bearing guided by radiographic union and absence of pain, typically at 6 to 12 weeks.
• Early passive and active-assisted flexion prevents recurrent arthrofibrosis; active resisted extension is protected until union is secure (the direction of quadriceps pull on the fragment). Quadriceps isometrics, straight-leg raises and ankle pumps begin immediately; closed-chain strengthening follows once union is established.
• Radiographs (AP and lateral) at 2, 6 and 12 weeks. Watch specifically for proximal migration of the fragment (impending nonunion). A new extensor lag in the early weeks warrants urgent imaging - it may be the first sign of fixation failure.
• Wound care: the prominent tubercle and thin revision soft tissues make wound breakdown a real risk; monitor closely, avoid tension on the closure, and keep the knee gently flexed to off-load the anterior skin. Complications and their prevention.

• Revision total knee arthroplasty - the principal operation done through this exposure, including component extraction and stem, cone or sleeve placement.
• Tibial tubercle osteotomy (Fulkerson or Maquet procedure) - the same osteotomy used for realignment; this extensile-exposure variant differs in its long flat fragment and rigid screw refixation.
• Medial parapatellar approach - the parent approach that the osteotomy extends.
• Open lysis of adhesions for arthrofibrosis after TKA.
• Complex primary TKA in the ankylosed, severely valgus or post-traumatic knee.
• Patella infera (baja) - transposition of the extensor mechanism proximally.
• Septic TKA two-stage exchange - wide access for radical debridement and component removal.
• Selected supracondylar or intra-articular distal femoral fractures around a TKA.

Guidelines, Registries & Global Practice

The tibial tubercle osteotomy for exposure is a long-established technique used worldwide in revision and complex knee arthroplasty. The principles converge across examination systems: a long flat fragment, a proximal step, a preserved lateral hinge, and rigid refixation, used when standard exposure fails in the stiff or revision knee.

Global practice variation: In high-resource settings, rigid screw fixation with modern small-fragment implants and routine CT assessment of union are standard. In resource-limited settings, the same biomechanical principles are achieved with available small-fragment screws or tension-band wire fixation; the lateral hinge and a long fragment remain the universal safeguards against nonunion regardless of implant. Consent (globally applicable): discuss the specific risks of this exposure - nonunion or migration of the tubercle fragment with an extensor lag, fracture of the fragment or the tibia, wound breakdown over the prominence, and (rare) injury to the anterior tibial vessels - alongside the usual revision-arthroplasty risks of infection, blood loss, stiffness and reoperation.