A distal extensile exposure of the knee — a long, laterally-pedicled osteotomy of the anterior tibial crest that lets the entire extensor mechanism be everted as one unit with the patellar tendon kept on bone.
- TTO preserves extensor mechanism continuity. A long osteotomy of the anterior tibial cortex carrying the tibial tubercle and attached patellar tendon allows the entire extensor mechanism (quadriceps-patella-patellar tendon-tubercle) to be everted and reflected as a single unit, keeping the patellar tendon in continuity with bone and avoiding the tendon disruption inherent to a quadriceps snip, V-Y quadricepsplasty or turndown.
- Primary indication is revision TKA with difficult exposure — a stiff knee (less than 70-90 degrees flexion), an ankylosed knee or severe arthrofibrosis where a medial parapatellar arthrotomy with lateral release will not allow safe patellar eversion or component access. TTO is the DISTAL extensile option; the quadriceps snip and V-Y quadricepsplasty are the PROXIMAL options (Younger 1998).
- Make the fragment LONG. A long anterior tibial fragment (longer than the patellar tendon insertion, commonly 6-10 cm; about 1-1.5 cm thick by 2-3 cm wide) spreads fixation forces over a long lever arm and resists the transverse stress-riser fracture seen with short button osteotomies. Whiteside's classic technique extends the cut 8-10 cm down the tibial crest.
- The pedicle is LATERAL, not medial. The fragment is hinged on a lateral musculoperiosteal sleeve (anterolateral periosteum and the origin of the anterior compartment musculature, including tibialis anterior) that maintains vascularity so it heals as a vascularised bone flap. Do NOT strip this lateral hinge bare. The medial side is where wires or screws are anchored — the pes anserinus is a medial structure and is NOT the pedicle.
- Secure fixation. Whiteside fixed the fragment with 2-3 transverse wires passed through the lateral edge of the fragment into the medial tibial cortex; lag screw fixation (2-3 cortical screws perpendicular to the osteotomy for interfragmentary compression, with washers if bone is poor) is a widely used alternative. Because the fragment is loaded in tension by the extensor mechanism, protected weight-bearing is needed until union.
- TTO keeps the tendon on bone. Bone-to-bone healing of the tubercle is generally more robust than the tendon or muscle healing required after a turndown, and it avoids the extensor lag and quadriceps weakness associated with a formal quadriceps turndown — making TTO the preferred distal extensile exposure when one is required.
When & Why
What it exposes. The tibial tubercle osteotomy (TTO) is an extensile exposure of the knee created by osteotomising a long pedicled segment of anterior tibial cortex that carries the tibial tubercle and the attached patellar tendon. Reflecting this fragment proximally lets the whole extensor mechanism (quadriceps-patella-patellar tendon-tubercle) be everted as one unit, giving wide access to the femoral, tibial and patellar components while keeping the patellar tendon in continuity with bone. Why TTO and not a proximal extensile option. Within a sensible escalation of exposure, a medial parapatellar arthrotomy with thorough scar excision and lateral release is tried first. If patellar eversion or component access is still inadequate, a quadriceps snip (quick, low-morbidity, allows immediate weight-bearing) or a distal TTO is added, with V-Y quadricepsplasty and femoral peel reserved for the most contracted knees (Younger 1998). The snip and the V-Y quadricepsplasty extend exposure PROXIMALLY; TTO extends it DISTALLY. The decisive advantage of TTO over a quadriceps turndown is that the patellar tendon stays on bone and the osteotomy heals bone-to-bone, avoiding the extensor lag and quadriceps weakness of a formal tendon disruption. Historical context. Leo Whiteside defined the long extended tibial tubercle and tibial crest osteotomy for difficult and revision knee arthroplasty: rather than a small tubercle button, the cut is carried 8-10 cm distally down the anterior tibia and hinged on a lateral musculoperiosteal sleeve. In his 1995 report of 136 TKAs (primary, revision, repeat-revision and infected) the fragment was reattached with 2-3 transverse wires into the medial cortex; there were no non-unions, only 2 partial proximal avulsions that did not displace widely, and quadriceps function was not compromised in any case (Clin Orthop Relat Res 1995;(321):32-5). Many surgeons now substitute cortical lag screws for wires. Position and landmarks. Supine with a leg holder on the proximal thigh (or the foot of the bed flexed with a bump under the thigh) so the knee can be flexed and extended without an assistant; a lateral post prevents external rotation. Use an upper-thigh tourniquet (some surgeons deflate it for the osteotomy and closure to confirm perfusion of the lateral pedicle), and position C-arm from the contralateral side for intra-operative fluoroscopy. Palpable landmarks are the tibial tubercle (patellar tendon insertion), the subcutaneous medial border of the tibial shaft (medial extent of the cut), Gerdy's tubercle laterally (lateral extent), and the inferior pole of the patella (marks the proximal tendon and the reference for osteotomy length). Indications. - Absolute: revision TKA with a stiff knee (less than 70 degrees flexion), an ankylosed knee or severe arthrofibrosis where standard exposure is inadequate; revision TKA needing extensive removal of well-fixed components or metaphyseal sleeves or cones (where forceful retraction risks extensor mechanism avulsion); acute or chronic patellar tendon avulsion repair (anatomic bone-to-bone reattachment); severe patellofemoral maltracking needing combined tubercle medialisation, distalisation and/or anteriorisation (Fulkerson osteotomy).
- Relative: primary TKA in a very stiff knee (less than 50 degrees flexion) where a quadriceps snip would otherwise be needed; extensor mechanism reconstruction in chronic patellar tendon rupture; tibial tubercle fracture malunion with patella baja (tubercle distalisation restores patellar height).
The Exposure
Work distal-to-proximal through the anterior tibial cortex, freeing the medial and distal borders while preserving the lateral musculoperiosteal pedicle, then hinge the fragment open laterally so the whole extensor mechanism can be everted as a unit.
Exposure sequence
- Supine with a leg holder or a bump under the thigh; upper-thigh tourniquet. Re-open the previous TKA incision (revision) or use a standard midline anterior incision (primary), extending it 8-10 cm distal to the tibial tubercle to reach the distal extent of the planned osteotomy.
- Raise full-thickness skin flaps deep to the fascia to expose the anterior tibial cortex from the tubercle to 8-10 cm distally, and clear the medial and lateral borders of the patellar tendon.
- Some surgeons deflate the tourniquet for the osteotomy and closure to confirm perfusion of the lateral pedicle.
- Mark a LONG fragment on the anterior tibia: length 6-8 cm (Whiteside carries it 8-10 cm down the crest), thickness about 1-1.5 cm (anterior cortex plus a thin layer of cancellous bone), width 2-3 cm centred on the tubercle. It must extend at least 1-2 cm distal to the patellar tendon insertion so the tendon stays on bone.
- Draw the medial border (parallel to the tendon), the lateral border, and the transverse distal line. Template the length on the pre-operative lateral X-ray before you start.
- Dimensions are non-negotiable: too short or too thin and the fragment fractures or avulses; too thick and closure is difficult with prominent hardware.
- With electrocautery, incise periosteum along the MEDIAL border (tubercle to distal extent) and across the DISTAL transverse line; elevate just enough sub-periosteum to define the medial cut.
- Do NOT strip the anterolateral periosteum or the anterior compartment muscle (the tibialis anterior origin). This lateral musculoperiosteal sleeve is the vascular pedicle and must stay attached to the fragment.
- The fragment is therefore freed medially and distally, hinging on the lateral cortex and periosteum until last.
- Drill a line of 2.0-3.2 mm holes (5-10 mm spacing) along the medial border and the distal line, aiming the cut to taper from the anterior cortex toward — but not through — the lateral cortex, so a thin anterior wafer is raised on a lateral hinge. Keep the cut shallow (anterior cortex plus a thin layer of cancellous bone); never penetrate the posterior cortex.
- Connect the holes with a thin 10-15 mm osteotome, working distal-to-proximal and freeing the medial and distal borders first, leaving the lateral hinge until last. Pre-drilling reduces the force needed to propagate the cut and lowers the fracture risk.
- Insert a wide 20-25 mm osteotome at the medial edge and gently lever the fragment open like a book, hinging it LATERALLY on its soft-tissue pedicle. Take the cut through bone, not along the lateral periosteum, so the musculoperiosteal sleeve stays attached.
- With the tubercle hinged laterally, evert the entire extensor mechanism (quadriceps-patella-patellar tendon-tubercle) as a single unit — the tendon stays in continuity with bone. Pad the fragment with a moist sponge and avoid excessive traction.
- The reflected extensor mechanism gives extensile exposure of the femoral, tibial and patellar components. Perform the intended work — component removal, cement extraction and reimplantation; anatomic tendon reattachment; or tubercle realignment.
- Keep the lateral pedicle moist and irrigate frequently to avoid heat necrosis from power tools.
- Return the fragment to its exact anatomical position (no shift unless realignment is planned), hold with pointed reduction clamps or K-wires, and confirm congruent bone contact — graft the surfaces if they are comminuted.
- Whiteside's classic fixation: 2-3 transverse wires passed through the lateral edge of the fragment into the medial tibial cortex, a tension band against the medial cortex that is especially useful when screw purchase is poor (osteoporosis).
- Widely used alternative: 2-3 cortical lag screws (4.0 or 4.5 mm) placed perpendicular to the osteotomy for interfragmentary compression, with washers in poor bone; bicortical purchase is essential.
- Confirm fixation fluoroscopically (AP and lateral — screws bicortical, not intra-articular) and flex the knee to 90 degrees: the fragment must be immobile, with no toggle.
- Reapproximate the medial periosteum and soft tissue over the reduced fragment (0-Vicryl) to recreate a periosteal sleeve; close in layers; apply a sterile dressing and a knee immobiliser in extension.
- Post-op: touch weight-bearing with an immobiliser for about 6 weeks, passive and active-assisted ROM 0-90 degrees, plus quadriceps sets and straight-leg raises; advance to partial weight-bearing at 6-12 weeks when early callus appears; full weight-bearing at 12 weeks once bridging callus is confirmed. Follow-up X-rays at 2, 6, 12 and 24 weeks.
The TTO fragment is vulnerable to intra-operative fracture or post-operative avulsion if its dimensions are inadequate or handling is traumatic. Five principles minimise the risk. (1) Adequate dimensions — a generous long anterior tibial fragment (6-10 cm length, longer than the tendon insertion; about 1-1.5 cm thickness for fixation purchase; 2-3 cm width) distributes load and resists a stress-riser fracture. (2) Preserve the lateral pedicle — leave the anterolateral periosteum and anterior compartment muscle attached so the fragment heals as a vascularised bone flap; do not strip it bare. (3) Gentle handling — propagate the cut with pre-drilled holes and osteotomes rather than a saw alone, and elevate slowly with wide instruments. (4) Secure fixation — Whiteside's 2-3 transverse wires into the medial cortex, or 2-3 cortical lag screws perpendicular to the osteotomy with washers in poor bone. (5) Protected weight-bearing — touch or partial weight-bearing for about 6 weeks (often in extension splintage), advancing to full weight-bearing once radiographic union is confirmed (commonly 8-12 weeks). In Whiteside's series of 136 TKAs there were no non-unions and only 2 partial proximal avulsions that did not displace widely.
In a stiff knee, choose and perform the extensile exposure EARLY rather than risk avulsing the patellar tendon by forced eversion (Younger 1998). If a medial parapatellar arthrotomy plus lateral release will not allow safe eversion, add a quadriceps snip for moderate needs or a distal TTO for the contracted knee, and reserve the V-Y quadricepsplasty for the most severe cases.
Examiners test whether you know which soft tissue keeps the fragment alive. The blood supply is the LATERAL musculoperiosteal sleeve (anterolateral periosteum and the tibialis anterior origin); the pes anserinus (sartorius, gracilis, semitendinosus) inserts medially and is not the pedicle. Free the medial and distal borders first and hinge on the lateral cortex last.
Dangers & Extensions
Contraindications.
Active knee infection (the osteotomy will not heal in the presence of infection); severe osteopenia or osteoporosis with inadequate bone for fixation; a previous failed TTO with non-union (repeat osteotomy carries a high failure risk — consider extensor mechanism allograft).
Adequate exposure achievable by less invasive means (standard medial parapatellar, subvastus, quadriceps snip); a poor soft-tissue envelope from multiple previous surgeries or radiation; a patient who cannot comply with a protected weight-bearing protocol (avulsion or non-union risk).
Structures at risk, by layer.
- Structure at risk
- Infrapatellar branch of the saphenous nerve (anteromedial knee numbness)
- Protection
- Identify if visible and retract; numbness is usually not functionally limiting but may be unavoidable
- Structure at risk
- Lateral musculoperiosteal pedicle (tibialis anterior origin and anterolateral periosteum)
- Protection
- Free the medial and distal borders first and hinge on the lateral cortex last; never strip the pedicle bare
- Structure at risk
- Popliteal neurovascular bundle
- Protection
- Keep the cut in the anterior 30-40% of the tibia (never beyond the midline on a lateral X-ray); use lateral fluoroscopy to confirm depth
- Structure at risk
- Extensor mechanism — proximal avulsion by patellar tendon pull
- Protection
- Rigid fixation (minimum 2-3 screws or wires in compression), touch weight-bearing for about 6 weeks, immobiliser for ambulation
Extensile alternatives — TTO versus the proximal options.
- Tibial Tubercle Osteotomy
- Excellent — entire extensor mechanism reflected proximally
- Quadriceps Turndown
- Excellent — full-thickness inverted-V incision gives wide exposure
- Quadriceps Snip
- Moderate — oblique cut across the proximal quadriceps tendon into vastus lateralis
- Tibial Tubercle Osteotomy
- DISTAL extensile option
- Quadriceps Turndown
- Proximal
- Quadriceps Snip
- Proximal
- Tibial Tubercle Osteotomy
- PRESERVED — patellar tendon stays in continuity on bone
- Quadriceps Turndown
- DISRUPTED — full-thickness muscle and tendon incision that must heal
- Quadriceps Snip
- Largely preserved — oblique tendon cut, vastus lateralis fibres incised
- Tibial Tubercle Osteotomy
- Bone-to-bone — generally robust union
- Quadriceps Turndown
- Tendon-to-tendon — requires tendon healing
- Quadriceps Snip
- Tendon and muscle reapproximation — reliable healing
- Tibial Tubercle Osteotomy
- Power well preserved; no compromise in Whiteside's series
- Quadriceps Turndown
- Highest risk of residual extensor lag and quadriceps weakness
- Quadriceps Snip
- Little reported strength loss
- Tibial Tubercle Osteotomy
- Fragment avulsion or non-union (mitigated by a long fragment, lateral pedicle, secure fixation)
- Quadriceps Turndown
- Extensor mechanism disruption and lag — the most morbid failure
- Quadriceps Snip
- May give insufficient exposure, then add TTO — low intrinsic morbidity
- Tibial Tubercle Osteotomy
- Touch weight-bearing for about 6 weeks
- Quadriceps Turndown
- Full weight-bearing immediately
- Quadriceps Snip
- Full weight-bearing immediately
- Tibial Tubercle Osteotomy
- HIGH — osteotomy, fixation expertise, pedicle preservation
- Quadriceps Turndown
- MODERATE — careful inverted-V design and meticulous closure
- Quadriceps Snip
- LOW — simple lateral release, easy closure
- Tibial Tubercle Osteotomy
- Stiff-knee revision TKA (less than 70 degrees flexion), extensive component removal, extensor mechanism repair
- Quadriceps Turndown
- Historical — largely replaced by TTO; only if TTO is contraindicated
- Quadriceps Snip
- Moderate exposure needs and simple revisions with adequate flexion
- The quadriceps snip suits moderate exposure needs — quick, low-morbidity, immediate weight-bearing; if it still does not allow safe eversion, escalate to a TTO or a V-Y quadricepsplasty (Younger 1998).
- Decide on the extensile manoeuvre EARLY rather than risk avulsing the patellar tendon by forced eversion (Younger 1998). Complications, by timing.
- Timing and recognition
- Intra-operative; cracks or shatters during elevation; more likely with a short or thin fragment
- Management
- Small non-displaced crack: proceed with compression fixation. Large or comminuted: abort to a snip or turndown, or fix the pieces with wires and bone graft (accepting higher non-union risk)
- Timing and recognition
- Intra-operative; the fragment is completely free and devascularised
- Management
- Preserve all remaining soft tissue, return it anatomically, rigid 3-screw fixation, bone graft, and extended protected weight-bearing (8-10 weeks)
- Timing and recognition
- Intra-operative; a drill or osteotome more than 1.5 cm deep risks the popliteal bundle
- Management
- Keep the cut in the anterior 30-40% of the tibia and confirm depth on lateral fluoroscopy; if arterial bleeding, extend and obtain a vascular surgery opinion
- Timing and recognition
- Early; dehiscence, drainage, or exposed prominent hardware
- Management
- Superficial: local wound care. Deep infection: irrigation and debridement with IV antibiotics (hardware removal if uncontrolled). Exposed hardware: soft-tissue or gastrocnemius flap cover
- Timing and recognition
- Weeks 2-6; a fall or premature weight-bearing; loss of straight-leg raise with proximal fragment migration
- Management
- URGENT return to theatre within 24-48 hours for reduction and AUGMENTED fixation (new screws in fresh holes plus cerclage wires and bone graft), with an immobiliser and 8-10 weeks of protected weight-bearing
- Timing and recognition
- Late; pain beyond 4-6 months with persistent lucency and no bridging callus
- Management
- Revision fixation with cancellous bone graft (autograft or allograft; consider BMP in high-risk patients); about 85-90% unite after revision and grafting
- Timing and recognition
- Late; painful screw heads with kneeling or direct pressure
- Management
- Observation if asymptomatic; remove hardware after union (typically 12-18 months), then protect from re-fracture for 4-6 weeks
- Timing and recognition
- Late after realignment; persistent maltracking or patella baja
- Management
- Revision osteotomy if symptomatic (high failure risk of 20-30%); observe if asymptomatic
Closure and extensile options. Extend the incision distally along the anterior tibial crest for more screw purchase, or proximally along the previous TKA incision. Reattach any medialised or distalised tubercle in its planned new position, repair the periosteal sleeve, close in layers, and splint in extension. If the reduction is not congruent (comminuted surfaces, a gap at the osteotomy), add cancellous bone graft to improve the healing biology.
Procedures Through This Approach
The principal use: stiff, ankylosed or arthrofibrotic knees (less than 70 degrees flexion), removal of well-fixed components and metaphyseal sleeves or cones, and septic two-stage exchange (spacer removal and reimplantation).
Acute or chronic patellar tendon avulsion — the osteotomy allows anatomic bone-to-bone reattachment of the tendon, and chronic extensor mechanism reconstruction where bone-to-bone healing is preferred.
Fulkerson anteromedialisation for lateral maltracking with lateral or distal facet chondrosis (medialisation recentres the patella, anteriorisation unloads the diseased facet), and tubercle distalisation for patella baja.
Viva & Exam Focus
TUBERCLETUBERCLE — the TTO technique, step by step
PEDICLEPEDICLE — preserving the lateral soft-tissue hinge
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“You are performing a revision TKA on a 72-year-old woman with a stiff knee (25 degrees flexion, 5 degrees extension) from severe arthrofibrosis 18 months after primary TKA. A standard medial parapatellar approach gives inadequate exposure, so you perform a tibial tubercle osteotomy. During elevation the fragment fractures into two pieces. What do you do immediately, and what are your options for proceeding?”
“A 68-year-old man had a revision TKA with tibial tubercle osteotomy fixed with three screws, the fragment well positioned on the post-op X-ray, and was counselled on strict touch weight-bearing for 6 weeks. At 4 weeks he presents with acute inability to perform a straight-leg raise after a fall at home. X-ray shows proximal displacement of the TTO fragment, pulled 15 mm from its original position. What has occurred, why, and what is your management plan?”
“A 55-year-old active man has severe anterior knee pain and recurrent patellar dislocations. Imaging shows lateral patellar maltracking with a TT-TG distance of 25 mm (normal less than 20 mm), an Insall-Salvati ratio of 0.65 (patella baja; normal 0.8-1.2), and focal lateral patellar facet Outerbridge grade 4 cartilage loss. What type of tibial tubercle osteotomy would you perform, what are the biomechanical goals, and what specific corrections are needed?”
Critical anatomy
- TTO fragment: long (commonly 6-10 cm) by about 1-1.5 cm thick by 2-3 cm wide, hinged on its LATERAL soft tissue
- Lateral pedicle: anterolateral periosteum plus anterior compartment muscle (tibialis anterior origin) — the blood supply and CRITICAL for healing; the medial pes anserinus is NOT the pedicle
- Osteotomy plane: oblique 30-45 degrees from the anterior cortex, tapering posteriorly distally to avoid a stress riser
- Patellar tendon insertion: the centre of the tibial tubercle — the osteotomy must include the entire insertion width
- Infrapatellar branch of the saphenous nerve: runs subcutaneously; anteromedial knee numbness if injured, usually not functionally limiting
Primary indications
- Revision TKA with a stiff knee (less than 70 degrees flexion) — extensile exposure without extensor mechanism disruption
- Revision TKA with well-fixed components needing extensive removal (power tools risk avulsion with forceful retraction)
- Patellar tendon avulsion repair (acute or chronic) — anatomic bone-to-bone reattachment
- Severe patellofemoral maltracking needing combined realignment (Fulkerson medialisation, anteriorisation, distalisation)
- Patella baja with extensor mechanism dysfunction (distalisation restores patellar height)
Surgical steps
- Position: supine with a leg holder; deflate the tourniquet for the osteotomy and closure to confirm pedicle perfusion (surgeon preference)
- Incision: extend the standard TKA incision 8-10 cm below the tubercle to reach the distal osteotomy
- Periosteum: free the MEDIAL and DISTAL borders only, hinging on the LATERAL musculoperiosteal pedicle (blood supply)
- Osteotomy: multiple drill holes at 5-10 mm spacing, connected with an osteotome, elevated distal-to-proximal with gentle wide instruments
- Fixation: 2-3 cortical screws (4.0 or 4.5 mm) perpendicular to the osteotomy for compression, or cerclage wires if osteoporotic
- Post-op: touch weight-bearing 6 weeks, partial 6-12 weeks, full from 12 weeks once radiographic union is confirmed
Complications
- Intra-operative fragment fracture — much more likely with a short or thin fragment; salvage if the pieces are large enough, otherwise abort to a snip or turndown
- Post-operative avulsion (weeks 2-6) — urgent return to theatre for reduction and augmented fixation (more screws and wires plus bone graft)
- Non-union — revision fixation with bone graft (BMP or autograft in high-risk patients); uncommon with a long pedicled fragment and secure fixation
- Prominent hardware — removal after union (often 12-18 months); protect from re-fracture after removal; kneeling discomfort may persist
- Intra-operative loss of the lateral pedicle — bone graft, extended protected weight-bearing, accept a higher non-union risk
Evidence
- Whiteside (Clin Orthop 1995;(321):32-5): extended TTO in 136 difficult TKAs with wire fixation — no non-unions, only 2 partial avulsions, quadriceps function preserved (PMID 7497683)
- Younger, Duncan and Masri (JAAOS 1998): perform the extensile manoeuvre EARLY (snip or turndown proximally, TTO distally) to avoid patellar tendon disruption (PMID 9692941)
- Segur (Arch Orthop Trauma Surg 2014): TTO in 26 septic two-stage revisions — 84.6% healed, 88.4% infection-free, 96.1% improved scores (PMID 25052772)
- Karamehmetoglu (Acta Orthop Traumatol Turc 2007): Fulkerson anteromedialisation for Outerbridge III-IV malalignment — 85.7% excellent, very good or good; mean anteriorisation 10.5 mm (PMID 17483632)
- Hurley and Sherman (Bone Joint J 2023): international Delphi — no consensus on TTO weight-bearing or immobilisation protocols, so quote ranges (PMID 38035602)
Exam-day power phrases
- TTO keeps the patellar tendon in continuity with bone and heals bone-to-bone, avoiding the extensor lag and quadriceps weakness of a formal quadriceps turndown — it is the preferred DISTAL extensile exposure when one is required
- The pedicle is LATERAL, not medial — the fragment hinges on the anterolateral periosteum and anterior compartment muscle, which keep it vascularised; the medial pes anserinus is not the pedicle
- Make the fragment LONG (longer than the tendon insertion, commonly 6-10 cm; about 1-1.5 cm thick by 2-3 cm wide) to spread fixation forces and resist a transverse stress-riser fracture — Whiteside extended his cut 8-10 cm down the crest
- Secure fixation matters: Whiteside used 2-3 transverse wires from the lateral fragment into the medial cortex; lag screws perpendicular to the osteotomy give interfragmentary compression — test stability by flexing the knee, then protect weight-bearing until union
- Fragment avulsion occurs in the vulnerable weeks 2-6 from a fall or premature weight-bearing — it needs URGENT return to theatre for reduction and augmented fixation, and the patient must be warned of the higher re-failure risk
- Fulkerson anteromedialisation combines anteriorisation (unloading the lateral or distal patellar facet) with medialisation (recentring the patella) for patellofemoral malalignment with lateral chondrosis — about 86% good or excellent results (Karamehmetoglu 2007)
References
Extended tibial tubercle osteotomy for difficult TKA exposure (landmark series)
- 136 total knee arthroplasties (1986-1994) exposed via an extended tibial tubercle and tibial crest osteotomy: 26 primary, 76 revision, 10 repeat revision, 19 infected and 5 repeat-revision for infection.
- The osteotomy gave adequate exposure without any need for further quadriceps mechanism release.
- Fixation was 2-3 wires passed through the lateral edge of the tibial tubercle and through the medial tibial cortex to reattach the bone fragment and patellar tendon.
- Outcomes: no non-unions (including the infected and repeat-elevation cases); only 2 tubercles had partial proximal avulsion fractures that did not displace widely; mean ROM 93.7 degrees (range 15-140 degrees) at 2 years.
- Quadriceps function was not compromised in any case; 3 wires were removed for pain.
Surgical exposures in revision TKA (escalation of extensile options)
- A well-planned approach must allow component removal, soft-tissue balancing, management of bone loss and reimplantation without damaging skin, the extensor mechanism, collateral ligaments, bone stock or neurovascular structures.
- Skin necrosis is avoided by appropriate incision selection and dissecting deep to the fascia (raising full-thickness flaps).
- Extensile exposure by scar excision, quadriceps snip or turndown, tibial tubercle osteotomy or medial epicondylar osteotomy should be performed EARLY to prevent patellar tendon disruption.
- In selected cases the distal femur is exposed circumferentially with a quadriceps myocutaneous flap or femoral peel.
- Special care is required in the infected or ankylosed knee.
TTO in septic (two-stage) revision TKA
- 26 patients underwent TTO as the approach at the second stage of a two-stage revision for prosthetic infection (mean follow-up 3.4 years).
- The osteotomy healed without complications in 22 patients (84.6%); non-union occurred in 2 patients.
- One patient had a residual 5 degree extension lag; 23 patients (88.4%) were free from infection.
- 25 patients (96.1%) had improved Knee Society and WOMAC scores after the procedure.
- TTO provided a wide operative field for spacer removal and reimplantation without damaging the extensor mechanism or altering rehabilitation.
Fulkerson (anteromedialisation) osteotomy for patellofemoral malalignment and arthrosis
- 21 knees in 18 patients (mean age 28.6 years) with chronic patellofemoral malalignment and severe lateral or distal patellar chondrosis (Outerbridge III-IV) treated with anteromedial tibial tubercle transfer.
- Mean anteriorisation 10.5 mm (range 7-15 mm); the vastus medialis obliquus was advanced in 7 knees.
- Results by Fulkerson criteria were excellent, very good or good in 18 knees (85.7%), fair in 2 (9.5%) and poor in 1 (4.8%); pain and instability scores improved significantly.
- Patellofemoral congruence angle and patellofemoral index improved significantly on tangential radiographs.
- Complications: one tibial tubercle avulsion, one DVT and four mild flexion contractures; no wound problems, compartment syndrome, peroneal palsy or proximal tibial fracture.
International Delphi consensus on patellar instability (anteromedialisation TTO)
- Modified Delphi process with 60 surgeons from 11 countries addressing MPFL reconstruction, anteromedialisation tibial tubercle osteotomy, trochleoplasty and rehabilitation in patellar instability.
- Of 41 statements, 19 reached strong consensus, 15 reached consensus and 7 reached no consensus.
- No consensus was reached on post-operative immobilisation or weight-bearing protocols — reflecting genuine global variation in TTO aftercare.
- Provides a contemporary, multinational reference frame for indications and adjuncts to tubercle osteotomy in instability.