High-yield overview

A long, lateralised osteotomy of the tibial tubercle that releases the extensor mechanism distally, converting an impossible exposure in the stiff or revision knee into a wide, safe one.

6-8 cmTypical osteotomy fragment length

SupinePatient position

3-4Cortical lag screws for refixation

LateralSoft-tissue hinge carrying the blood supply

Critical Must-Knows

A long flat osteotomy of the anterior tibial cortex (about 6 to 8 cm) carries the tibial tubercle up with the whole extensor mechanism as one continuous unit.
A proximal step cut is mandatory - it prevents proximal escape of the fragment under quadriceps pull.
The lateral tibialis-anterior and periosteal hinge is preserved and carries the blood supply; the medial side is stripped, so the mechanism is everted laterally.
There is no true internervous plane - this is an extensile osteotomy of the extensor mechanism, not an inter-nerval interval.
Rigid screw refixation (3 to 4 bicortical cortical screws engaging the posterior cortex) is required to avoid nonunion and proximal migration.

When & Why

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.

Extensile Exposures of the Stiff or Revision Knee
Technique	Level of release	Exposure gained	Morbidity and weakness	Best use
Quadriceps snip (Insall)	Proximal	Moderate	Low - repaired side-to-side, slight extensor lag, recover quickly	First-line for mild-to-moderate stiffness
V-Y turndown (Coonse-Adams)	Proximal	Extensive	High - extension lag, quadriceps weakness, patella baja risk	Severe stiffness only, last resort
Tibial tubercle osteotomy	Distal	Extensive	Low-to-moderate - quadriceps intact; depends on union	Stiff or revision knee, patella baja
Pie-crusting of the quadriceps expansion	Proximal	Modest	Low	Mild tightness, adjunct rather than primary release

The Exposure

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.

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Image Needed: Clinical PhotoHigh Priority

Intra-operative photograph of a tibial tubercle osteotomy for extensile knee exposure: a long anterior incision over the proximal tibia, a flat osteotomy of the anteromedial cortex with a proximal step cut, the tibial tubercle fragment hinged laterally on the tibialis-anterior attachment carrying the whole extensor mechanism, and the knee joint widely exposed.

Context: A verified image is being sourced for this exposure.

Pending image generation or sourcing

Exposure sequence

Step 1Position, incision and arthrotomy

Supine on a radiolucent table with a bump under the ipsilateral hip to control external rotation; tourniquet high on the thigh; foot of the table dropped or a sandbag under the foot so the knee flexes freely past 90 degrees.
Use the previous anterior scar (revision) or a long longitudinal anterior incision extending far enough distally onto the tibial crest to expose the full intended fragment (typically to the crest 8 to 10 cm below the joint line).
Landmarks: tibial tubercle, patellar tendon, patella, joint line, anterior tibial crest, and Gerdy's tubercle (the anterolateral IT-band insertion, just medial to the lateral hinge).
Carry out a standard medial parapatellar arthrotomy. Assess whether the patella can be everted; if it cannot, proceed to the osteotomy.

Step 2Mark the osteotomy

Outline a long trapezoidal fragment on the anteromedial tibia: wide proximally across the base of the tubercle, tapering distally along the crest, about 6 to 8 cm long.
Plan a deliberate proximal step cut at the proximal extent - this is not optional.

Step 3The proximal step cut (mandatory)

First make the transverse step cut at the proximal extent of the fragment, angled so it creates a bony buttress pointing distally.
This is what prevents the fragment migrating proximally under quadriceps pull - without it the fragment escapes and the construct fails.

Step 4The long flat cut

With an oscillating saw, make the medial and distal cuts along the marked lines, staying on the anteromedial cortex.
The cut is flat (or very slightly oblique), broad proximally and tapering distally.
Keep the saw blade shallow, especially proximally, to avoid penetrating the posterior cortex and endangering the anterior tibial vessels.

Step 5Complete the osteotomy laterally - preserve the hinge

Use osteotomes to crack the lateral cortex as a hinge rather than cutting it completely.
The fragment now remains attached laterally by the tibialis-anterior and periosteal hinge - the blood supply; the medial side is freed subperiosteally.

Step 6Evert the extensor mechanism

With the tubercle fragment mobile on its lateral hinge, lift the whole extensor mechanism - quadriceps, patella, tendon and tubercle - and evert it laterally, hinging on the preserved lateral attachment.
The knee joint is now widely exposed from the tibial plateau to the suprapatellar pouch; flex the knee to deliver the joint into the wound.

Step 7Perform the index procedure

With wide exposure, carry out the planned work: component extraction, bone grafting, lysis of adhesions, stem, cone or sleeve placement in revision, or fracture fixation as required.

Step 8Reduce and rigidly fix the fragment

Bring the extensor mechanism back and reduce the tubercle fragment anatomically into its bed.
Fix it with rigid compression: typically 3 to 4 bicortical 4.5 mm cortical screws in lag or interfragmentary fashion engaging the posterior tibial cortex.
Measure length carefully - the screw tips should just perforate the far cortex without threatening the posterior neurovascular bundle. In poor bone, supplement with a small-fragment plate, tension-band wires or cables.

Step 9Soft-tissue closure

Repair the medial retinaculum and arthrotomy in the usual layered fashion over the reduced, fixed fragment.
Close the skin meticulously - the prominent tubercle and the often-thin revision soft tissues make wound breakdown a real risk.

The anterior tibial vessels and the lateral hinge are the two things you must not injure

The anterior tibial artery and deep peroneal nerve pass forwards over the upper border of the interosseous membrane just distal to the knee and run distally on its anterior surface. They are closest to the cut at the proximal end of the osteotomy through the posterior cortex - the danger zone for the saw, the osteotome and over-long screws. Keep the proximal cut shallow, complete it under control with osteotomes, and measure screws to the far cortex only. Equally, never divide the lateral tibialis-anterior hinge - it is the blood supply on which union of the fragment depends.

There is no true internervous plane

This is not an internervous-plane approach in the Hoppenfeld sense. The tibial tubercle osteotomy is an extensile osteotomy of the extensor mechanism. Dissection passes subperiosteally on the anteromedial tibia between the patellar tendon and the tibial cortex; the tibialis anterior (deep peroneal nerve) is deliberately left attached laterally, not developed as an inter-nerval interval. If asked in the viva, state plainly: there is no internervous plane; the fragment is kept vascularised through its lateral hinge.

Dangers & Extensions

Structures at risk, by layer.

Danger structures and how to protect them
Layer	Structure at risk	How it is endangered	Protection
Superficial	Patellar tendon	Forcing eversion before the osteotomy is complete	Complete the osteotomy before everting; never lever against the tendon
Superficial	Infrapatellar branch of the saphenous nerve	Skin incision	Accept sensory numbness; protect where possible
Deep (proximal)	Anterior tibial artery and veins	Saw or osteotome penetrating the posterior cortex at the proximal cut; over-long screws	Keep the proximal cut shallow; complete with osteotomes; measure screws to the far cortex only
Deep	Deep peroneal nerve	Same deep or posterior penetration	Stay on the anterior cortex; shallow proximal cut
Bone	Tibial tubercle fragment	Too thin leads to intra-operative fracture; omitted step or short fragment leads to migration; inadequate fixation leads to nonunion	Cut a long, adequately thick fragment with a proximal step; preserve the lateral hinge; rigid fixation
Late	Tibial diaphysis	Stress fracture through screw holes	Use the minimum number of screws; do not over-countersink

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.

Complications of the tibial tubercle osteotomy
Complication	Prevention	Management
Fragment migration or nonunion	Long fragment, proximal step, lateral hinge, rigid fixation	Protected mobilisation; surgical re-fixation if established (screws, tension band, cables, plate)
Intra-operative fragment fracture	Cut an adequately thick fragment; do not over-thin	Revise fixation with a plate or tension band
Anterior tibial vessel or deep peroneal nerve injury	Keep the proximal cut shallow; measure screws to the far cortex	Intra-operative vascular repair if recognised; post-operative exploration if ischaemia
Wound breakdown or infection	Meticulous soft-tissue handling; avoid tension; prophylactic antibiotics	Wound care, debridement, suppressive or staged management as severity dictates
Tibial stress fracture (through screw holes)	Use the minimum number of screws; do not over-countersink	Protected weight-bearing; fixation if displaced
Extensor lag	Preserve quadriceps continuity; achieve union; structured rehabilitation	Brace, quadriceps rehabilitation; allograft if the mechanism is disrupted

Procedures Through This Approach

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.

Viva & Exam Focus

Mnemonic

TUBERCLETUBERCLE - the extensile-exposure osteotomy

Tibial tubercle carried up

With the whole extensor mechanism as one continuous unit

Un-evertable patella

Used for the stiff, scarred or ankylosed revision knee

Bone fragment long and thick

About 6 to 8 cm, with a proximal bevel or step cut

Evert laterally

On the preserved tibialis-anterior hinge

Rigid screw refixation

3 to 4 bicortical cortical lag screws engaging the posterior cortex

Closure anatomical

Reduce the fragment, repair the retinaculum, flex to confirm tracking

Lateral hinge is the blood supply

The medial side is stripped, so preserve the lateral side at all costs

Extensible

Connects proximally with the medial parapatellar arthrotomy and distally along the crest

Mnemonic

SAFERSAFER - avoiding tubercle fragment failure

Step cut proximally

Mandatory - mechanically prevents proximal migration under quadriceps pull

Anterior tibial artery protected

And deep peroneal nerve - keep the proximal cut shallow, measure screws to the far cortex

Fragment long

Greater than 6 cm and not too thin - short or wafer-thin fragments migrate, fracture or fail to unite

Evert on the lateral hinge

Preserve the tibialis-anterior hinge - it is the blood supply on which union depends

Rigid interfragmentary fixation

3 to 4 cortical lag screws; add a plate, wires or cables in poor bone

Exam Viva Scenarios

Practise clinical reasoning and management decisions out loud

Viva scenarioStandard

Clinical prompt

“You are performing a revision total knee arthroplasty in a 68-year-old woman with a stiff, multiply-operated knee. Through your medial parapatellar arthrotomy the patella will not evert without avulsing the tendon. How do you gain safe extensile exposure?”

Practical approach

This is the classic indication for a tibial tubercle osteotomy. Forcing eversion risks patellar tendon avulsion or patellar fracture, so I release the extensor mechanism distally. **Decision:** I have already made a standard medial parapatellar arthrotomy. A quadriceps snip is the usual first escalation, but in a knee this stiff and scarred - and especially if there is any patella baja - I proceed directly to a tibial tubercle osteotomy because it gives the widest exposure while preserving quadriceps continuity. **Technique:** I mark a long, trapezoidal fragment on the anteromedial tibia, about 6 to 8 cm long, broad proximally across the base of the tubercle and tapering distally along the crest. I first make a transverse proximal step cut - this is mandatory, because it prevents the fragment migrating proximally under quadriceps pull. With an oscillating saw I make the medial and distal cuts on the anteromedial cortex, keeping the blade shallow proximally to avoid penetrating the posterior cortex and endangering the anterior tibial vessels. I complete the cut laterally with osteotomes, leaving the lateral cortex and the tibialis-anterior attachment intact as a vascularised hinge. The fragment is then everted laterally on this hinge, carrying the whole extensor mechanism with it and exposing the joint widely. **The danger structures I protect:** the patellar tendon (by completing the osteotomy before everting), the anterior tibial artery and deep peroneal nerve (by keeping the proximal cut shallow and measuring screws to the far cortex), and the blood supply of the fragment itself (the lateral hinge). **Fixation and closure:** once the revision work is done I reduce the fragment anatomically and fix it with 3 to 4 bicortical cortical lag screws engaging the posterior cortex, then repair the retinaculum and close meticulously over the prominent tubercle. I protect the extensor mechanism post-operatively.

Key clinical points

Classic indication: a stiff, scarred revision knee where the patella will not evert

Tubercle osteotomy releases the extensor mechanism distally while preserving quadriceps continuity

Long fragment (greater than 6 cm) with a mandatory proximal step cut to prevent proximal migration

Preserve the lateral tibialis-anterior hinge - it is the blood supply

Evert laterally on the hinge for wide exposure

Anterior tibial vessels endangered at the proximal cut - keep it shallow and measure screws

Rigid 3-to-4-screw lag fixation gives reliable union

Common pitfalls

Forcing eversion and avulsing the patellar tendon before completing the osteotomy

Cutting a short fragment or omitting the proximal step - the fragment migrates proximally and fails

Dividing the lateral hinge and devascularising the fragment

Deep posterior penetration at the proximal cut injuring the anterior tibial artery

Not knowing how this contrasts with the quadriceps snip and the V-Y turndown

Further questions

“What is your post-operative rehabilitation and weight-bearing regime after this osteotomy?”

Viva scenarioChallenging

Clinical prompt

“Six weeks after a revision knee arthroplasty performed with a tibial tubercle osteotomy, a patient presents with an increasing extensor lag and pain over the tubercle. A lateral radiograph shows the fragment has migrated proximally. What has gone wrong and how do you manage it?”

Practical approach

The fragment has failed by proximal migration - the complication the technique is specifically designed to prevent. The most likely technical causes are a fragment that was too short, omission or inadequacy of the proximal step cut, or insufficient fixation. **Assessment:** I examine the extensor mechanism for an extensor lag and any palpable defect, review the operative note (fragment length, whether a step cut was made, fixation used), and obtain weight-bearing AP and lateral radiographs plus a CT to confirm migration, the state of the fragment, and early nonunion. I look for wound breakdown over the prominent fragment. **Why it happened:** a short fragment has a small surface area for union and is easily pulled proximally by the quadriceps; without a buttressing proximal step there is nothing to resist that force; and inadequate fixation (too few screws, poor bone, single-wire fixation) allows motion at the osteotomy. **Initial management:** if the fragment is still in reasonable apposition and there is no complete extensor failure, I may protect the limb in a cylinder cast or brace in extension and restrict active extension while reassessing. However, an established proximal migration with an extensor lag usually requires surgery. **Surgical management:** I would revise the fixation. Options depend on fragment and bone quality - rigid re-fixation with bicortical screws if the fragment is substantial, supplemented by a tension band, a small-fragment plate, or cables if the bone is poor. If the fragment is comminuted or the extensor mechanism is disrupted, reconstruction with an extensor mechanism allograft or, in selected cases, a mesh and graft may be required. I would counsel the patient about a guarded prognosis and a residual extensor lag. **Prevention is key:** this is why the technique insists on a long fragment, a proximal step cut, the lateral hinge, and rigid screw fixation.

Key clinical points

Proximal migration is the hallmark complication of an inadequate TTO

Technical causes: short fragment, absent or inadequate proximal step cut, insufficient fixation

Assess with radiographs and CT; examine for an extensor lag and wound breakdown

Early cases may be managed protectively; established migration with lag needs surgery

Revision options: rigid screw re-fixation, tension band, plate, cables, or extensor mechanism allograft for disruption

Prevention rests on the long fragment, the step cut, the lateral hinge and rigid fixation

Common pitfalls

Reassuring the patient that the lag will recover without imaging the fragment

Re-fixing into poor bone without augmentation (tension band, cables, plate)

Not recognising extensor mechanism disruption that needs allograft reconstruction

Blaming patient factors without analysing the technical cause of migration

Further questions

“What intra-operative steps specifically prevent proximal migration of the fragment?”

Viva scenarioStandard

Clinical prompt

“Compare and contrast the quadriceps snip, the V-Y turndown and the tibial tubercle osteotomy as extensile exposures of the stiff knee. When would you use each?”

Practical approach

These three releases form a spectrum from least to most morbid, and from proximal to distal. The choice depends on how much extra exposure is needed and how much weakness the patient can accept. **Quadriceps snip (Insall):** a proximal oblique cut made at the apex of the medial parapatellar arthrotomy through the rectus and quadriceps tendon, angled superolaterally. It is repaired side-to-side. It gives moderate additional exposure, heals reliably, and produces only a slight extensor lag that recovers with quadriceps rehabilitation. It is the first-line release for mild-to-moderate stiffness because of its low morbidity. **V-Y turndown (Coonse-Adams, modified by Insall):** an inverted V or Y cut of the quadriceps expansion that allows the whole extensor mechanism to be turned down distally. It gives the most extensive exposure of the three but at significant cost: an extension lag, quadriceps weakness, and a risk of patella baja. It is reserved for the most severely ankylosed knees where the other releases are insufficient, and the patient must accept the weakness. **Tibial tubercle osteotomy:** a distal release - a long flat osteotomy of the anteromedial tibia that elevates the tubercle with the whole extensor mechanism, which is then everted laterally on a preserved tibialis-anterior hinge. It gives extensive exposure comparable to the V-Y but, because the quadriceps tendon is never divided, quadriceps continuity and power are largely preserved. Its morbidity is low-to-moderate and depends on union of the fragment, which is reliable with a long fragment, a proximal step and rigid screw fixation. It is my choice for the stiff or revision knee once a snip is insufficient, and it is the only release that addresses patella baja by transposing the mechanism proximally. **In practice:** I start with the snip; if the patella still will not deliver, I add a tibial tubercle osteotomy; I reserve the V-Y for the worst ankylosed knees.

Key clinical points

Snip: proximal, moderate exposure, low morbidity, first-line

V-Y turndown: proximal, most exposure, high morbidity (lag, weakness, patella baja), last resort

Tibial tubercle osteotomy: distal, extensive exposure, low-to-moderate morbidity, quadriceps preserved

TTO is the only release that addresses patella baja

Decision logic: escalate from snip to TTO, with V-Y reserved for severe ankylosis

TTO morbidity depends on union of the fragment - prevent migration with a long fragment and step cut

Common pitfalls

Confusing the level of release (snip and V-Y are proximal; TTO is distal)

Overstating snip exposure or understating V-Y morbidity

Forgetting that the TTO preserves quadriceps continuity unlike the V-Y

Not knowing that TTO is the option for patella baja

Further questions

“How does each release affect post-operative rehabilitation and weight-bearing?”

Exam day cheat sheet

Tibial tubercle osteotomy for extensile exposure - exam-day essentials

Indications

Stiff or revision TKA where the patella will not evert
Arthrofibrosis requiring open lysis of adhesions
Complex primary in the ankylosed, severely valgus or post-traumatic knee
Patella infera (baja) blocking delivery of the patella
Selected septic revisions and supracondylar fractures around a TKA

Position & Landmarks

Supine with a hip bump, tourniquet, knee free to flex past 90 degrees
Landmarks: tibial tubercle, patellar tendon, patella, joint line, anterior tibial crest, Gerdy's tubercle
Use the previous scar or a long anterior incision extending distally onto the crest
Incorporate a standard medial parapatellar arthrotomy
Prep the whole anterior tibial crest into the field

The Osteotomy Technique

Long flat osteotomy of the anteromedial cortex, about 6 to 8 cm, broad proximally tapering distally
Mandatory proximal step cut - prevents proximal migration under quadriceps pull
Cut the medial and distal limbs with a saw; keep the proximal cut shallow
Complete laterally with osteotomes, leaving the lateral cortex as a hinge
Preserve the tibialis-anterior and periosteal lateral hinge - the blood supply
Evert the whole extensor mechanism laterally on the hinge for wide exposure

Internervous Plane & Vascularity

No true internervous plane - this is an extensile osteotomy of the extensor mechanism
Subperiosteal dissection between the patellar tendon and the tibial cortex
Medial side stripped; lateral side intact and vascularised
Fragment blood supply runs lateral-to-medial through the tibialis-anterior hinge
No motor nerve is divided

Danger Structures

Patellar tendon - avulsion if eversion is forced before the osteotomy is complete
Anterior tibial artery - crosses the upper border of the interosseous membrane just distal to the knee
Deep peroneal nerve - runs with the anterior tibial artery on the interosseous membrane
Posterior cortex at the proximal cut is the danger zone for saw, osteotome and screws
Late: tibial stress fracture through screw holes; wound breakdown over the prominent fragment

Fixation, Closure & Complications

Reduce anatomically and fix rigidly - 3 to 4 bicortical 4.5 mm cortical lag screws
Measure screws to the far cortex only; supplement with plate, wires or cables in poor bone
Repair the retinaculum and close meticulously over the fragment
Avoid nonunion and migration: long fragment, proximal step, lateral hinge, rigid fixation
Contrast with snip (least morbid) and V-Y (most morbid); TTO preserves quadriceps continuity

References

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 (advanced orthopaedic practice or advanced orthopaedic practice, DNB or MS, MRCS, SICOT): 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.

Where global guidance converges on the stiff or revision knee exposure
Body	Position on the stiff or revision knee exposure
AAOS (US)	An extensor-mechanism release (snip, V-Y or tibial tubercle osteotomy) is justified when the patella cannot be safely everted; the choice balances exposure gained against extensor morbidity
NICE and BOA (UK)	In revision arthroplasty, protect the extensor mechanism and avoid avulsion; document the exposure strategy and its consented risks (nonunion, lag, wound breakdown)
EFORT and European consensus	TTO is an accepted extensile exposure for revision and ankylosed knees; emphasise rigid fixation and soft-tissue cover over the prominent tubercle
AO Foundation	Principles of small-fragment fixation apply: lag screws for compression, neutralisation if the fragment is fragile, and protection of soft-tissue vascularity for union

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.

Orthopaedic relevance

For the operative surgery and revision-arthroplasty stations, be able to describe the tibial tubercle osteotomy systematically: the indication (the knee that will not evert), the long flat fragment with a proximal step, the lateral tibialis-anterior hinge as the blood supply, the absence of a true internervous plane, the danger to the anterior tibial vessels, and the rigid screw refixation. Know how it contrasts with the quadriceps snip and the V-Y turndown.

Evidence

Exposure in difficult total knee arthroplasty: tibial tubercle osteotomy

LoE 4

Whiteside LA • Clinical Orthopaedics and Related Research (1995)

Key Findings:

The landmark description of the flat tibial tubercle osteotomy with an intact lateral soft-tissue hinge for wide exposure in difficult and revision total knee arthroplasty
The fragment remains attached laterally to the tibialis anterior, preserving its blood supply, and is re-fixed with screws
Reported reliable healing of the osteotomy and preservation of extensor mechanism function
Established the technique as the standard extensile exposure for the stiff or revision knee

Evidence

Osteotomy of the tibial tubercle in total knee replacement: a technical note

LoE 4

Dolin MG • Acta Orthopaedica Scandinavica (1983)

Key Findings:

An early technical description of elevating the tibial tubercle with the extensor mechanism to improve exposure in total knee replacement
Outlined the osteotomy and refixation principles on which later standardised techniques were built
Recognised the need to preserve soft-tissue attachment to the fragment for healing
Provided the foundation for the modern extensile-exposure osteotomy

Evidence

The results of tibial tubercle osteotomy after total knee arthroplasty

LoE 4

Mendes MW, Caldwell P, Jiranek WA • The Knee (2004)

Key Findings:

Reported the outcomes and complications of tibial tubercle osteotomy performed in the setting of total knee arthroplasty
Identified nonunion and proximal migration of the fragment as the principal complications
Complications were frequently associated with short fragments or inadequate fixation
Supported the use of a long fragment with rigid screw fixation to minimise failure

Evidence

Mechanical comparison of fixation techniques for the tibial tubercle osteotomy

LoE 4

Davis K, Caldwell P, Wayne J, Jiranek WA • Journal of Arthroplasty (2000)

Key Findings:

A biomechanical study comparing methods of refixation of the tibial tubercle osteotomy
Rigid screw fixation provided superior construct stability compared with wire-only techniques
Supported the clinical preference for interfragmentary screw fixation to resist quadriceps pull
Informed fixation choice in poor-quality bone where augmentation may be needed

Evidence

Arthroplasty for the stiff or ankylosed knee

LoE 4

Aglietti P, Windsor RE, Buzzi R, Insall JN • Journal of Arthroplasty (1989)

Key Findings:

A classic description of total knee arthroplasty in the stiff and ankylosed knee, where standard exposure is impossible
Defined the role of extensile exposures including quadriceps snip, V-Y turndown and tibial tubercle osteotomy
Highlighted the balance between gaining exposure and preserving extensor mechanism function
Established the conceptual framework for escalating from the snip to the tibial tubercle osteotomy